[V13,12/12] PCI: tegra: Add Tegra194 PCIe support

Add support for Synopsys DesignWare core IP based PCIe host controller
present in Tegra194 SoC.

Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
---
V13:
* Modified according to modifications in PATCH V13 01/12

V12:
* None

V11:
* None

V10:
* Used _relaxed() versions of readl() & writel()

V9:
* Made it dependent on ARCH_TEGRA_194_SOC directly

V8:
* Addressed review comments from Thierry

V7:
* Removed code around "nvidia,disable-aspm-states" DT property
* Refactored code to remove code duplication

V6:
* Addressed review comments from Thierry

V5:
* None

V4:
* None

V3:
* Changed 'nvidia,init-speed' to 'nvidia,init-link-speed'
* Changed 'nvidia,pex-wake' to 'nvidia,wake-gpios'
* Removed .runtime_suspend() & .runtime_resume() implementations

V2:
* Made CONFIG_PCIE_TEGRA194 as 'm' by default from its previous 'y' state
* Modified code as per changes made to DT documentation
* Refactored code to address Bjorn & Thierry's review comments
* Added goto to avoid recursion in tegra_pcie_dw_host_init() API
* Merged .scan_bus() of dw_pcie_host_ops implementation to tegra_pcie_dw_host_init() API

 drivers/pci/controller/dwc/Kconfig         |   10 +
 drivers/pci/controller/dwc/Makefile        |    1 +
 drivers/pci/controller/dwc/pcie-tegra194.c | 1632 ++++++++++++++++++++
 3 files changed, 1643 insertions(+)
 create mode 100644 drivers/pci/controller/dwc/pcie-tegra194.c

On Wed, Jul 10, 2019 at 11:52:12AM +0530, Vidya Sagar wrote:

[...]

> +#if defined(CONFIG_PCIEASPM)
> +static void disable_aspm_l11(struct tegra_pcie_dw *pcie)
> +{
> +	u32 val;
> +
> +	val = dw_pcie_readl_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub);
> +	val &= ~PCI_L1SS_CAP_ASPM_L1_1;
> +	dw_pcie_writel_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub, val);
> +}
> +
> +static void disable_aspm_l12(struct tegra_pcie_dw *pcie)
> +{
> +	u32 val;
> +
> +	val = dw_pcie_readl_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub);
> +	val &= ~PCI_L1SS_CAP_ASPM_L1_2;
> +	dw_pcie_writel_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub, val);
> +}
> +
> +static inline u32 event_counter_prog(struct tegra_pcie_dw *pcie, u32 event)
> +{
> +	u32 val;
> +
> +	val = dw_pcie_readl_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid]);
> +	val &= ~(EVENT_COUNTER_EVENT_SEL_MASK << EVENT_COUNTER_EVENT_SEL_SHIFT);
> +	val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
> +	val |= event << EVENT_COUNTER_EVENT_SEL_SHIFT;
> +	val |= EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
> +	dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid], val);
> +	val = dw_pcie_readl_dbi(&pcie->pci, event_cntr_data_offset[pcie->cid]);
> +	return val;
> +}
> +
> +static int aspm_state_cnt(struct seq_file *s, void *data)
> +{
> +	struct tegra_pcie_dw *pcie = (struct tegra_pcie_dw *)
> +				     dev_get_drvdata(s->private);
> +	u32 val;
> +
> +	seq_printf(s, "Tx L0s entry count : %u\n",
> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_Tx_L0S));
> +
> +	seq_printf(s, "Rx L0s entry count : %u\n",
> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_Rx_L0S));
> +
> +	seq_printf(s, "Link L1 entry count : %u\n",
> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1));
> +
> +	seq_printf(s, "Link L1.1 entry count : %u\n",
> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1_1));
> +
> +	seq_printf(s, "Link L1.2 entry count : %u\n",
> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1_2));
> +
> +	/* Clear all counters */
> +	dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid],
> +			   EVENT_COUNTER_ALL_CLEAR);
> +
> +	/* Re-enable counting */
> +	val = EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
> +	val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
> +	dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid], val);
> +
> +	return 0;
> +}
> +#endif
> +
> +static int init_debugfs(struct tegra_pcie_dw *pcie)
> +{
> +#if defined(CONFIG_PCIEASPM)
> +	struct dentry *d;
> +
> +	d = debugfs_create_devm_seqfile(pcie->dev, "aspm_state_cnt",
> +					pcie->debugfs, aspm_state_cnt);
> +	if (IS_ERR_OR_NULL(d))
> +		dev_err(pcie->dev,
> +			"Failed to create debugfs file \"aspm_state_cnt\"\n");
> +#endif
> +	return 0;
> +}

I prefer writing it:

#if defined(CONFIG_PCIEASPM)
static void disable_aspm_l11(struct tegra_pcie_dw *pcie)
{
...
}

static void disable_aspm_l12(struct tegra_pcie_dw *pcie)
{
...
}

static inline u32 event_counter_prog(struct tegra_pcie_dw *pcie, u32 event)
{
...
}

static int aspm_state_cnt(struct seq_file *s, void *data)
{
...
}

static int init_debugfs(struct tegra_pcie_dw *pcie)
{
	struct dentry *d;

	d = debugfs_create_devm_seqfile(pcie->dev, "aspm_state_cnt",
					pcie->debugfs, aspm_state_cnt);
	if (IS_ERR_OR_NULL(d))
		dev_err(pcie->dev,
			"Failed to create debugfs file \"aspm_state_cnt\"\n");
	return 0;
}
#else
static inline int init_debugfs(struct tegra_pcie_dw *pcie) { return 0; }
#endif

> +
> +static void tegra_pcie_enable_system_interrupts(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> +	u32 val;
> +	u16 val_w;
> +
> +	val = appl_readl(pcie, APPL_INTR_EN_L0_0);
> +	val |= APPL_INTR_EN_L0_0_LINK_STATE_INT_EN;
> +	appl_writel(pcie, val, APPL_INTR_EN_L0_0);
> +
> +	val = appl_readl(pcie, APPL_INTR_EN_L1_0_0);
> +	val |= APPL_INTR_EN_L1_0_0_LINK_REQ_RST_NOT_INT_EN;
> +	appl_writel(pcie, val, APPL_INTR_EN_L1_0_0);
> +
> +	if (pcie->enable_cdm_check) {
> +		val = appl_readl(pcie, APPL_INTR_EN_L0_0);
> +		val |= APPL_INTR_EN_L0_0_CDM_REG_CHK_INT_EN;
> +		appl_writel(pcie, val, APPL_INTR_EN_L0_0);
> +
> +		val = appl_readl(pcie, APPL_INTR_EN_L1_18);
> +		val |= APPL_INTR_EN_L1_18_CDM_REG_CHK_CMP_ERR;
> +		val |= APPL_INTR_EN_L1_18_CDM_REG_CHK_LOGIC_ERR;
> +		appl_writel(pcie, val, APPL_INTR_EN_L1_18);
> +	}
> +
> +	val_w = dw_pcie_readw_dbi(&pcie->pci, pcie->pcie_cap_base +
> +				  PCI_EXP_LNKSTA);
> +	pcie->init_link_width = (val_w & PCI_EXP_LNKSTA_NLW) >>
> +				PCI_EXP_LNKSTA_NLW_SHIFT;
> +
> +	val_w = dw_pcie_readw_dbi(&pcie->pci, pcie->pcie_cap_base +
> +				  PCI_EXP_LNKCTL);
> +	val_w |= PCI_EXP_LNKCTL_LBMIE;
> +	dw_pcie_writew_dbi(&pcie->pci, pcie->pcie_cap_base + PCI_EXP_LNKCTL,
> +			   val_w);
> +}
> +
> +static void tegra_pcie_enable_legacy_interrupts(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> +	u32 val;
> +
> +	/* Enable legacy interrupt generation */
> +	val = appl_readl(pcie, APPL_INTR_EN_L0_0);
> +	val |= APPL_INTR_EN_L0_0_SYS_INTR_EN;
> +	val |= APPL_INTR_EN_L0_0_INT_INT_EN;
> +	appl_writel(pcie, val, APPL_INTR_EN_L0_0);
> +
> +	val = appl_readl(pcie, APPL_INTR_EN_L1_8_0);
> +	val |= APPL_INTR_EN_L1_8_INTX_EN;
> +	val |= APPL_INTR_EN_L1_8_AUTO_BW_INT_EN;
> +	val |= APPL_INTR_EN_L1_8_BW_MGT_INT_EN;
> +	if (IS_ENABLED(CONFIG_PCIEAER))
> +		val |= APPL_INTR_EN_L1_8_AER_INT_EN;
> +	appl_writel(pcie, val, APPL_INTR_EN_L1_8_0);
> +}
> +
> +static void tegra_pcie_enable_msi_interrupts(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> +	u32 val;
> +
> +	dw_pcie_msi_init(pp);
> +
> +	/* Enable MSI interrupt generation */
> +	val = appl_readl(pcie, APPL_INTR_EN_L0_0);
> +	val |= APPL_INTR_EN_L0_0_SYS_MSI_INTR_EN;
> +	val |= APPL_INTR_EN_L0_0_MSI_RCV_INT_EN;
> +	appl_writel(pcie, val, APPL_INTR_EN_L0_0);
> +}
> +
> +static void tegra_pcie_enable_interrupts(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> +
> +	/* Clear interrupt statuses before enabling interrupts */
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L0);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_0_0);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_1);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_2);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_3);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_6);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_7);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_8_0);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_9);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_10);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_11);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_13);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_14);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_15);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_17);
> +
> +	tegra_pcie_enable_system_interrupts(pp);
> +	tegra_pcie_enable_legacy_interrupts(pp);
> +	if (IS_ENABLED(CONFIG_PCI_MSI))
> +		tegra_pcie_enable_msi_interrupts(pp);
> +}
> +
> +static void config_gen3_gen4_eq_presets(struct tegra_pcie_dw *pcie)
> +{
> +	struct dw_pcie *pci = &pcie->pci;
> +	u32 val, offset, i;
> +
> +	/* Program init preset */
> +	for (i = 0; i < pcie->num_lanes; i++) {
> +		dw_pcie_read(pci->dbi_base + CAP_SPCIE_CAP_OFF
> +				 + (i * 2), 2, &val);
> +		val &= ~CAP_SPCIE_CAP_OFF_DSP_TX_PRESET0_MASK;
> +		val |= GEN3_GEN4_EQ_PRESET_INIT;
> +		val &= ~CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_MASK;
> +		val |= (GEN3_GEN4_EQ_PRESET_INIT <<
> +			   CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_SHIFT);
> +		dw_pcie_write(pci->dbi_base + CAP_SPCIE_CAP_OFF
> +				 + (i * 2), 2, val);
> +
> +		offset = dw_pcie_find_ext_capability(pci,
> +						     PCI_EXT_CAP_ID_PL_16GT) +
> +				PCI_PL_16GT_LE_CTRL;
> +		dw_pcie_read(pci->dbi_base + offset + i, 1, &val);
> +		val &= ~PCI_PL_16GT_LE_CTRL_DSP_TX_PRESET_MASK;
> +		val |= GEN3_GEN4_EQ_PRESET_INIT;
> +		val &= ~PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_MASK;
> +		val |= (GEN3_GEN4_EQ_PRESET_INIT <<
> +			PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_SHIFT);
> +		dw_pcie_write(pci->dbi_base + offset + i, 1, val);
> +	}
> +
> +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
> +	val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
> +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
> +
> +	val = dw_pcie_readl_dbi(pci, GEN3_EQ_CONTROL_OFF);
> +	val &= ~GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK;
> +	val |= (0x3ff << GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_SHIFT);
> +	val &= ~GEN3_EQ_CONTROL_OFF_FB_MODE_MASK;
> +	dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, val);
> +
> +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
> +	val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
> +	val |= (0x1 << GEN3_RELATED_OFF_RATE_SHADOW_SEL_SHIFT);
> +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
> +
> +	val = dw_pcie_readl_dbi(pci, GEN3_EQ_CONTROL_OFF);
> +	val &= ~GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK;
> +	val |= (0x360 << GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_SHIFT);
> +	val &= ~GEN3_EQ_CONTROL_OFF_FB_MODE_MASK;
> +	dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, val);
> +
> +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
> +	val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
> +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
> +}
> +
> +static int tegra_pcie_dw_host_init(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> +	u32 val, tmp, offset, speed;
> +	unsigned int count;
> +	u16 val_w;
> +
> +core_init:

Why should we restart from here ? What's the effect of the reset
on following registers set-up ?

> +	count = 200;
> +#if defined(CONFIG_PCIEASPM)
> +	offset = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_L1SS);
> +	pcie->cfg_link_cap_l1sub = offset + PCI_L1SS_CAP;
> +#endif

Can we group it in the #ifdef above ?

> +	val = dw_pcie_readl_dbi(pci, PCI_IO_BASE);
> +	val &= ~(IO_BASE_IO_DECODE | IO_BASE_IO_DECODE_BIT8);
> +	dw_pcie_writel_dbi(pci, PCI_IO_BASE, val);
> +
> +	val = dw_pcie_readl_dbi(pci, PCI_PREF_MEMORY_BASE);
> +	val |= CFG_PREF_MEM_LIMIT_BASE_MEM_DECODE;
> +	val |= CFG_PREF_MEM_LIMIT_BASE_MEM_LIMIT_DECODE;
> +	dw_pcie_writel_dbi(pci, PCI_PREF_MEMORY_BASE, val);
> +
> +	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 0);
> +
> +	/* Configure FTS */
> +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL);
> +	val &= ~(N_FTS_MASK << N_FTS_SHIFT);
> +	val |= N_FTS_VAL << N_FTS_SHIFT;
> +	dw_pcie_writel_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL, val);
> +
> +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_GEN2_CTRL);
> +	val &= ~FTS_MASK;
> +	val |= FTS_VAL;
> +	dw_pcie_writel_dbi(pci, PORT_LOGIC_GEN2_CTRL, val);
> +
> +	/* Enable as 0xFFFF0001 response for CRS */
> +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT);
> +	val &= ~(AMBA_ERROR_RESPONSE_CRS_MASK << AMBA_ERROR_RESPONSE_CRS_SHIFT);
> +	val |= (AMBA_ERROR_RESPONSE_CRS_OKAY_FFFF0001 <<
> +		AMBA_ERROR_RESPONSE_CRS_SHIFT);
> +	dw_pcie_writel_dbi(pci, PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT, val);
> +
> +	/* Configure Max Speed from DT */
> +	if (pcie->max_speed && pcie->max_speed != -EINVAL) {
> +		val = dw_pcie_readl_dbi(pci, pcie->pcie_cap_base +
> +					PCI_EXP_LNKCAP);
> +		val &= ~PCI_EXP_LNKCAP_SLS;
> +		val |= pcie->max_speed;
> +		dw_pcie_writel_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP,
> +				   val);
> +	}
> +
> +	/* Configure Max lane width from DT */
> +	val = dw_pcie_readl_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP);
> +	val &= ~PCI_EXP_LNKCAP_MLW;
> +	val |= (pcie->num_lanes << PCI_EXP_LNKSTA_NLW_SHIFT);
> +	dw_pcie_writel_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP, val);
> +
> +	config_gen3_gen4_eq_presets(pcie);
> +
> +#if defined(CONFIG_PCIEASPM)
> +	/* Enable ASPM counters */
> +	val = EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
> +	val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
> +	dw_pcie_writel_dbi(pci, event_cntr_ctrl_offset[pcie->cid], val);
> +
> +	/* Program T_cmrt and T_pwr_on values */
> +	val = dw_pcie_readl_dbi(pci, pcie->cfg_link_cap_l1sub);
> +	val &= ~(PCI_L1SS_CAP_CM_RESTORE_TIME | PCI_L1SS_CAP_P_PWR_ON_VALUE);
> +	val |= (pcie->aspm_cmrt << 8);
> +	val |= (pcie->aspm_pwr_on_t << 19);
> +	dw_pcie_writel_dbi(pci, pcie->cfg_link_cap_l1sub, val);
> +
> +	/* Program L0s and L1 entrance latencies */
> +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL);
> +	val &= ~L0S_ENTRANCE_LAT_MASK;
> +	val |= (pcie->aspm_l0s_enter_lat << L0S_ENTRANCE_LAT_SHIFT);
> +	val |= ENTER_ASPM;
> +	dw_pcie_writel_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL, val);
> +#endif

It would be good to group all init guarded in CONFIG_PCIEASPM in
one function and related ifdef guard.

> +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
> +	val &= ~GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL;
> +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
> +
> +	if (pcie->update_fc_fixup) {
> +		val = dw_pcie_readl_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF);
> +		val |= 0x1 << CFG_TIMER_CTRL_ACK_NAK_SHIFT;
> +		dw_pcie_writel_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF, val);
> +	}
> +
> +	dw_pcie_setup_rc(pp);
> +
> +	clk_set_rate(pcie->core_clk, GEN4_CORE_CLK_FREQ);
> +
> +	/* Assert RST */
> +	val = appl_readl(pcie, APPL_PINMUX);
> +	val &= ~APPL_PINMUX_PEX_RST;
> +	appl_writel(pcie, val, APPL_PINMUX);

What's the effect of this RST on the registers programmed above ?

> +	usleep_range(100, 200);
> +
> +	/* Enable LTSSM */
> +	val = appl_readl(pcie, APPL_CTRL);
> +	val |= APPL_CTRL_LTSSM_EN;
> +	appl_writel(pcie, val, APPL_CTRL);
> +
> +	/* De-assert RST */
> +	val = appl_readl(pcie, APPL_PINMUX);
> +	val |= APPL_PINMUX_PEX_RST;
> +	appl_writel(pcie, val, APPL_PINMUX);
> +
> +	msleep(100);
> +
> +	val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
> +	while (!(val_w & PCI_EXP_LNKSTA_DLLLA)) {
> +		if (count) {
> +			dev_dbg(pci->dev, "Waiting for link up\n");
> +			usleep_range(1000, 2000);
> +			val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
> +						  PCI_EXP_LNKSTA);
> +			count--;
> +			continue;
> +		}
> +
> +		val = appl_readl(pcie, APPL_DEBUG);
> +		val &= APPL_DEBUG_LTSSM_STATE_MASK;
> +		val >>= APPL_DEBUG_LTSSM_STATE_SHIFT;
> +		tmp = appl_readl(pcie, APPL_LINK_STATUS);
> +		tmp &= APPL_LINK_STATUS_RDLH_LINK_UP;
> +		if (!(val == 0x11 && !tmp)) {
> +			dev_info(pci->dev, "Link is down\n");
> +			return 0;
> +		}
> +
> +		dev_info(pci->dev, "Link is down in DLL");
> +		dev_info(pci->dev, "Trying again with DLFE disabled\n");
> +		/* Disable LTSSM */
> +		val = appl_readl(pcie, APPL_CTRL);
> +		val &= ~APPL_CTRL_LTSSM_EN;
> +		appl_writel(pcie, val, APPL_CTRL);
> +
> +		reset_control_assert(pcie->core_rst);
> +		reset_control_deassert(pcie->core_rst);
> +
> +		offset = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_DLF);
> +		val = dw_pcie_readl_dbi(pci, offset + PCI_DLF_CAP);
> +		val &= ~PCI_DLF_EXCHANGE_ENABLE;
> +		dw_pcie_writel_dbi(pci, offset, val);
> +
> +		/* Retry now with DLF Exchange disabled */
> +		goto core_init;

See above.

> +	}
> +	dev_dbg(pci->dev, "Link is up\n");
> +
> +	speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
> +		PCI_EXP_LNKSTA_CLS;
> +	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
> +
> +	tegra_pcie_enable_interrupts(pp);
> +
> +	return 0;
> +}
> +
> +static int tegra_pcie_dw_link_up(struct dw_pcie *pci)
> +{
> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> +	u32 val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
> +
> +	return !!(val & PCI_EXP_LNKSTA_DLLLA);
> +}
> +
> +static void tegra_pcie_set_msi_vec_num(struct pcie_port *pp)
> +{
> +	pp->num_vectors = MAX_MSI_IRQS;
> +}
> +
> +static const struct dw_pcie_ops tegra_dw_pcie_ops = {
> +	.link_up = tegra_pcie_dw_link_up,
> +};
> +
> +static struct dw_pcie_host_ops tegra_pcie_dw_host_ops = {
> +	.rd_own_conf = tegra_pcie_dw_rd_own_conf,
> +	.wr_own_conf = tegra_pcie_dw_wr_own_conf,
> +	.host_init = tegra_pcie_dw_host_init,
> +	.set_num_vectors = tegra_pcie_set_msi_vec_num,
> +};
> +
> +static void tegra_pcie_disable_phy(struct tegra_pcie_dw *pcie)
> +{
> +	unsigned int phy_count = pcie->phy_count;
> +
> +	while (phy_count--) {
> +		phy_power_off(pcie->phys[phy_count]);
> +		phy_exit(pcie->phys[phy_count]);
> +	}
> +}
> +
> +static int tegra_pcie_enable_phy(struct tegra_pcie_dw *pcie)
> +{
> +	unsigned int i;
> +	int ret;
> +
> +	for (i = 0; i < pcie->phy_count; i++) {
> +		ret = phy_init(pcie->phys[i]);
> +		if (ret < 0)
> +			goto phy_power_off;
> +
> +		ret = phy_power_on(pcie->phys[i]);
> +		if (ret < 0)
> +			goto phy_exit;
> +	}
> +
> +	return 0;
> +
> +phy_power_off:
> +	while (i--) {
> +		phy_power_off(pcie->phys[i]);
> +phy_exit:
> +		phy_exit(pcie->phys[i]);
> +	}
> +
> +	return ret;
> +}
> +
> +static int tegra_pcie_dw_parse_dt(struct tegra_pcie_dw *pcie)
> +{
> +	struct device_node *np = pcie->dev->of_node;
> +	int ret;
> +
> +	ret = of_property_read_u32(np, "nvidia,aspm-cmrt-us", &pcie->aspm_cmrt);
> +	if (ret < 0) {
> +		dev_info(pcie->dev, "Failed to read ASPM T_cmrt: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = of_property_read_u32(np, "nvidia,aspm-pwr-on-t-us",
> +				   &pcie->aspm_pwr_on_t);
> +	if (ret < 0)
> +		dev_info(pcie->dev, "Failed to read ASPM Power On time: %d\n",
> +			 ret);
> +
> +	ret = of_property_read_u32(np, "nvidia,aspm-l0s-entrance-latency-us",
> +				   &pcie->aspm_l0s_enter_lat);
> +	if (ret < 0)
> +		dev_info(pcie->dev,
> +			 "Failed to read ASPM L0s Entrance latency: %d\n", ret);
> +
> +	ret = of_property_read_u32(np, "num-lanes", &pcie->num_lanes);
> +	if (ret < 0) {
> +		dev_err(pcie->dev, "Failed to read num-lanes: %d\n", ret);
> +		return ret;
> +	}
> +
> +	pcie->max_speed = of_pci_get_max_link_speed(np);
> +
> +	ret = of_property_read_u32_index(np, "nvidia,bpmp", 1, &pcie->cid);
> +	if (ret) {
> +		dev_err(pcie->dev, "Failed to read Controller-ID: %d\n", ret);
> +		return ret;
> +	}
> +
> +	pcie->phy_count = of_property_count_strings(np, "phy-names");
> +	if (pcie->phy_count < 0) {
> +		dev_err(pcie->dev, "Failed to find PHY entries: %d\n",
> +			pcie->phy_count);
> +		return pcie->phy_count;
> +	}
> +
> +	if (of_property_read_bool(np, "nvidia,update-fc-fixup"))
> +		pcie->update_fc_fixup = true;
> +
> +	pcie->supports_clkreq =
> +		of_property_read_bool(pcie->dev->of_node, "supports-clkreq");
> +
> +	pcie->enable_cdm_check =
> +		of_property_read_bool(np, "snps,enable-cdm-check");
> +
> +	return 0;
> +}
> +
> +static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
> +					  bool enable)
> +{
> +	struct mrq_uphy_response resp;
> +	struct tegra_bpmp_message msg;
> +	struct mrq_uphy_request req;
> +	int err;
> +
> +	if (pcie->cid == 5)
> +		return 0;
> +
> +	memset(&req, 0, sizeof(req));
> +	memset(&resp, 0, sizeof(resp));
> +
> +	req.cmd = CMD_UPHY_PCIE_CONTROLLER_STATE;
> +	req.controller_state.pcie_controller = pcie->cid;
> +	req.controller_state.enable = enable;
> +
> +	memset(&msg, 0, sizeof(msg));
> +	msg.mrq = MRQ_UPHY;
> +	msg.tx.data = &req;
> +	msg.tx.size = sizeof(req);
> +	msg.rx.data = &resp;
> +	msg.rx.size = sizeof(resp);
> +
> +	if (irqs_disabled())
> +		err = tegra_bpmp_transfer_atomic(pcie->bpmp, &msg);
> +	else
> +		err = tegra_bpmp_transfer(pcie->bpmp, &msg);
> +
> +	return err;
> +}
> +
> +static void tegra_pcie_downstream_dev_to_D0(struct tegra_pcie_dw *pcie)
> +{
> +	struct pcie_port *pp = &pcie->pci.pp;
> +	struct pci_dev *pdev;
> +	struct pci_bus *child;
> +
> +	list_for_each_entry(child, &pp->root_bus->children, node) {
> +		/* Bring downstream devices to D0 if they are not already in */
> +		if (child->parent == pp->root_bus)
> +			break;
> +	}
> +	list_for_each_entry(pdev, &child->devices, bus_list) {
> +		if (PCI_SLOT(pdev->devfn) == 0) {
> +			if (pci_set_power_state(pdev, PCI_D0))
> +				dev_err(pcie->dev,
> +					"Failed to transition %s to D0 state\n",
> +					dev_name(&pdev->dev));
> +		}
> +	}
> +}
> +
> +static int tegra_pcie_config_controller(struct tegra_pcie_dw *pcie,
> +					bool en_hw_hot_rst)
> +{
> +	int ret;
> +	u32 val;
> +
> +	ret = tegra_pcie_bpmp_set_ctrl_state(pcie, true);
> +	if (ret) {
> +		dev_err(pcie->dev,
> +			"Failed to enable controller %u: %d\n", pcie->cid, ret);
> +		return ret;
> +	}
> +
> +	ret = regulator_enable(pcie->pex_ctl_supply);
> +	if (ret < 0) {
> +		dev_err(pcie->dev, "Failed to enable regulator: %d\n", ret);
> +		goto fail_reg_en;
> +	}
> +
> +	ret = clk_prepare_enable(pcie->core_clk);
> +	if (ret) {
> +		dev_err(pcie->dev, "Failed to enable core clock: %d\n", ret);
> +		goto fail_core_clk;
> +	}
> +
> +	ret = reset_control_deassert(pcie->core_apb_rst);
> +	if (ret) {
> +		dev_err(pcie->dev, "Failed to deassert core APB reset: %d\n",
> +			ret);
> +		goto fail_core_apb_rst;
> +	}
> +
> +	if (en_hw_hot_rst) {
> +		/* Enable HW_HOT_RST mode */
> +		val = appl_readl(pcie, APPL_CTRL);
> +		val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
> +			 APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
> +		val |= APPL_CTRL_HW_HOT_RST_EN;
> +		appl_writel(pcie, val, APPL_CTRL);
> +	}
> +
> +	ret = tegra_pcie_enable_phy(pcie);
> +	if (ret) {
> +		dev_err(pcie->dev, "Failed to enable PHY: %d\n", ret);
> +		goto fail_phy;
> +	}
> +
> +	/* Update CFG base address */
> +	appl_writel(pcie, pcie->dbi_res->start & APPL_CFG_BASE_ADDR_MASK,
> +		    APPL_CFG_BASE_ADDR);
> +
> +	/* Configure this core for RP mode operation */
> +	appl_writel(pcie, APPL_DM_TYPE_RP, APPL_DM_TYPE);
> +
> +	appl_writel(pcie, 0x0, APPL_CFG_SLCG_OVERRIDE);
> +
> +	val = appl_readl(pcie, APPL_CTRL);
> +	appl_writel(pcie, val | APPL_CTRL_SYS_PRE_DET_STATE, APPL_CTRL);
> +
> +	val = appl_readl(pcie, APPL_CFG_MISC);
> +	val |= (APPL_CFG_MISC_ARCACHE_VAL << APPL_CFG_MISC_ARCACHE_SHIFT);
> +	appl_writel(pcie, val, APPL_CFG_MISC);
> +
> +	if (!pcie->supports_clkreq) {
> +		val = appl_readl(pcie, APPL_PINMUX);
> +		val |= APPL_PINMUX_CLKREQ_OUT_OVRD_EN;
> +		val |= APPL_PINMUX_CLKREQ_OUT_OVRD;
> +		appl_writel(pcie, val, APPL_PINMUX);
> +	}
> +
> +	/* Update iATU_DMA base address */
> +	appl_writel(pcie,
> +		    pcie->atu_dma_res->start & APPL_CFG_IATU_DMA_BASE_ADDR_MASK,
> +		    APPL_CFG_IATU_DMA_BASE_ADDR);
> +
> +	reset_control_deassert(pcie->core_rst);
> +
> +	pcie->pcie_cap_base = dw_pcie_find_capability(&pcie->pci,
> +						      PCI_CAP_ID_EXP);
> +
> +#if defined(CONFIG_PCIEASPM)
> +	/* Disable ASPM-L1SS advertisement as there is no CLKREQ routing */
> +	if (!pcie->supports_clkreq) {
> +		disable_aspm_l11(pcie);
> +		disable_aspm_l12(pcie);
> +	}
> +#endif
> +	return ret;
> +
> +fail_phy:
> +	reset_control_assert(pcie->core_apb_rst);
> +fail_core_apb_rst:
> +	clk_disable_unprepare(pcie->core_clk);
> +fail_core_clk:
> +	regulator_disable(pcie->pex_ctl_supply);
> +fail_reg_en:
> +	tegra_pcie_bpmp_set_ctrl_state(pcie, false);
> +
> +	return ret;
> +}
> +
> +static int __deinit_controller(struct tegra_pcie_dw *pcie)
> +{
> +	int ret;
> +
> +	ret = reset_control_assert(pcie->core_rst);
> +	if (ret) {
> +		dev_err(pcie->dev, "Failed to assert \"core\" reset: %d\n",
> +			ret);
> +		return ret;
> +	}
> +	tegra_pcie_disable_phy(pcie);
> +	ret = reset_control_assert(pcie->core_apb_rst);
> +	if (ret) {
> +		dev_err(pcie->dev, "Failed to assert APB reset: %d\n", ret);
> +		return ret;
> +	}
> +	clk_disable_unprepare(pcie->core_clk);
> +	ret = regulator_disable(pcie->pex_ctl_supply);
> +	if (ret) {
> +		dev_err(pcie->dev, "Failed to disable regulator: %d\n", ret);
> +		return ret;
> +	}
> +	ret = tegra_pcie_bpmp_set_ctrl_state(pcie, false);
> +	if (ret) {
> +		dev_err(pcie->dev, "Failed to disable controller %d: %d\n",
> +			pcie->cid, ret);
> +		return ret;
> +	}
> +	return ret;
> +}
> +
> +static int tegra_pcie_init_controller(struct tegra_pcie_dw *pcie)
> +{
> +	struct dw_pcie *pci = &pcie->pci;
> +	struct pcie_port *pp = &pci->pp;
> +	int ret;
> +
> +	ret = tegra_pcie_config_controller(pcie, false);
> +	if (ret < 0)
> +		return ret;
> +
> +	pp->root_bus_nr = -1;

Useless, drop it, it is initialized in dw_pcie_host_init().

> +	pp->ops = &tegra_pcie_dw_host_ops;
> +
> +	ret = dw_pcie_host_init(pp);
> +	if (ret < 0) {
> +		dev_err(pcie->dev, "Failed to add PCIe port: %d\n", ret);
> +		goto fail_host_init;
> +	}
> +
> +	return 0;
> +
> +fail_host_init:
> +	return __deinit_controller(pcie);
> +}
> +
> +static int tegra_pcie_try_link_l2(struct tegra_pcie_dw *pcie)
> +{
> +	u32 val;
> +
> +	if (!tegra_pcie_dw_link_up(&pcie->pci))
> +		return 0;
> +
> +	val = appl_readl(pcie, APPL_RADM_STATUS);
> +	val |= APPL_PM_XMT_TURNOFF_STATE;
> +	appl_writel(pcie, val, APPL_RADM_STATUS);
> +
> +	return readl_poll_timeout_atomic(pcie->appl_base + APPL_DEBUG, val,
> +				 val & APPL_DEBUG_PM_LINKST_IN_L2_LAT,
> +				 1, PME_ACK_TIMEOUT);
> +}
> +
> +static void tegra_pcie_dw_pme_turnoff(struct tegra_pcie_dw *pcie)
> +{
> +	u32 data;
> +	int err;
> +
> +	if (!tegra_pcie_dw_link_up(&pcie->pci)) {
> +		dev_dbg(pcie->dev, "PCIe link is not up...!\n");
> +		return;
> +	}
> +
> +	if (tegra_pcie_try_link_l2(pcie)) {
> +		dev_info(pcie->dev, "Link didn't transition to L2 state\n");
> +		/*
> +		 * TX lane clock freq will reset to Gen1 only if link is in L2
> +		 * or detect state.
> +		 * So apply pex_rst to end point to force RP to go into detect
> +		 * state
> +		 */
> +		data = appl_readl(pcie, APPL_PINMUX);
> +		data &= ~APPL_PINMUX_PEX_RST;
> +		appl_writel(pcie, data, APPL_PINMUX);
> +
> +		err = readl_poll_timeout_atomic(pcie->appl_base + APPL_DEBUG,
> +						data,
> +						((data &
> +						APPL_DEBUG_LTSSM_STATE_MASK) >>
> +						APPL_DEBUG_LTSSM_STATE_SHIFT) ==
> +						LTSSM_STATE_PRE_DETECT,
> +						1, LTSSM_TIMEOUT);
> +		if (err) {
> +			dev_info(pcie->dev, "Link didn't go to detect state\n");
> +		} else {
> +			/* Disable LTSSM after link is in detect state */
> +			data = appl_readl(pcie, APPL_CTRL);
> +			data &= ~APPL_CTRL_LTSSM_EN;
> +			appl_writel(pcie, data, APPL_CTRL);
> +		}
> +	}
> +	/*
> +	 * DBI registers may not be accessible after this as PLL-E would be
> +	 * down depending on how CLKREQ is pulled by end point
> +	 */
> +	data = appl_readl(pcie, APPL_PINMUX);
> +	data |= (APPL_PINMUX_CLKREQ_OVERRIDE_EN | APPL_PINMUX_CLKREQ_OVERRIDE);
> +	/* Cut REFCLK to slot */
> +	data |= APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE_EN;
> +	data &= ~APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE;
> +	appl_writel(pcie, data, APPL_PINMUX);
> +}
> +
> +static int tegra_pcie_deinit_controller(struct tegra_pcie_dw *pcie)
> +{
> +	/*
> +	 * link doesn't go into L2 state with some of the endpoints with Tegra
> +	 * if they are not in D0 state. So, need to make sure that immediate
> +	 * downstream devices are in D0 state before sending PME_TurnOff to put
> +	 * link into L2 state
> +	 */
> +	tegra_pcie_downstream_dev_to_D0(pcie);
> +	dw_pcie_host_deinit(&pcie->pci.pp);
> +	tegra_pcie_dw_pme_turnoff(pcie);
> +	return __deinit_controller(pcie);
> +}
> +
> +static int tegra_pcie_config_rp(struct tegra_pcie_dw *pcie)
> +{
> +	struct pcie_port *pp = &pcie->pci.pp;
> +	struct device *dev = pcie->dev;
> +	char *name;
> +	int ret;
> +
> +	if (IS_ENABLED(CONFIG_PCI_MSI)) {
> +		pp->msi_irq = of_irq_get_byname(dev->of_node, "msi");
> +		if (!pp->msi_irq) {
> +			dev_err(dev, "Failed to get MSI interrupt\n");
> +			return -ENODEV;
> +		}
> +	}
> +
> +	pm_runtime_enable(dev);
> +	ret = pm_runtime_get_sync(dev);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to get runtime sync for PCIe dev: %d\n",
> +			ret);
> +		pm_runtime_disable(dev);
> +		return ret;
> +	}
> +
> +	tegra_pcie_init_controller(pcie);
> +
> +	pcie->link_state = tegra_pcie_dw_link_up(&pcie->pci);
> +
> +	if (!pcie->link_state) {
> +		ret = -ENOMEDIUM;
> +		goto fail_host_init;
> +	}
> +
> +	name = devm_kasprintf(dev, GFP_KERNEL, "%pOFP", dev->of_node);
> +	if (!name) {
> +		ret = -ENOMEM;
> +		goto fail_host_init;
> +	}
> +
> +	pcie->debugfs = debugfs_create_dir(name, NULL);
> +	if (!pcie->debugfs)
> +		dev_err(dev, "Failed to create debugfs\n");
> +	else
> +		init_debugfs(pcie);
> +
> +	return ret;
> +
> +fail_host_init:
> +	tegra_pcie_deinit_controller(pcie);
> +	pm_runtime_put_sync(dev);
> +	pm_runtime_disable(dev);
> +	return ret;
> +}
> +
> +static const struct tegra_pcie_soc tegra_pcie_rc_of_data = {
> +	.mode = DW_PCIE_RC_TYPE,
> +};
> +
> +static const struct of_device_id tegra_pcie_dw_of_match[] = {
> +	{
> +		.compatible = "nvidia,tegra194-pcie",
> +		.data = &tegra_pcie_rc_of_data,
> +	},
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, tegra_pcie_dw_of_match);

Move it closer to end of file where MODULE_DESCRIPTION() et al are.

> +
> +static int tegra_pcie_dw_probe(struct platform_device *pdev)
> +{
> +	const struct tegra_pcie_soc *data;
> +	struct device *dev = &pdev->dev;
> +	struct resource *atu_dma_res;
> +	struct tegra_pcie_dw *pcie;
> +	struct resource *dbi_res;
> +	struct pcie_port *pp;
> +	struct dw_pcie *pci;
> +	struct phy **phys;
> +	char *name;
> +	int ret;
> +	u32 i;
> +
> +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> +	if (!pcie)
> +		return -ENOMEM;
> +
> +	pci = &pcie->pci;
> +	pci->dev = &pdev->dev;
> +	pci->ops = &tegra_dw_pcie_ops;
> +	pp = &pci->pp;
> +	pcie->dev = &pdev->dev;
> +
> +	data = (struct tegra_pcie_soc *)of_device_get_match_data(dev);
> +	if (!data)
> +		return -EINVAL;
> +	pcie->mode = (enum dw_pcie_device_mode)data->mode;
> +
> +	ret = tegra_pcie_dw_parse_dt(pcie);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to parse device tree: %d\n", ret);
> +		return ret;
> +	}
> +
> +	pcie->pex_ctl_supply = devm_regulator_get(dev, "vddio-pex-ctl");
> +	if (IS_ERR(pcie->pex_ctl_supply)) {
> +		dev_err(dev, "Failed to get regulator: %ld\n",
> +			PTR_ERR(pcie->pex_ctl_supply));
> +		return PTR_ERR(pcie->pex_ctl_supply);
> +	}
> +
> +	pcie->core_clk = devm_clk_get(dev, "core");
> +	if (IS_ERR(pcie->core_clk)) {
> +		dev_err(dev, "Failed to get core clock: %ld\n",
> +			PTR_ERR(pcie->core_clk));
> +		return PTR_ERR(pcie->core_clk);
> +	}
> +
> +	pcie->appl_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> +						      "appl");
> +	if (!pcie->appl_res) {
> +		dev_err(dev, "Failed to find \"appl\" region\n");
> +		return PTR_ERR(pcie->appl_res);
> +	}

Add an empty line.

> +	pcie->appl_base = devm_ioremap_resource(dev, pcie->appl_res);
> +	if (IS_ERR(pcie->appl_base))
> +		return PTR_ERR(pcie->appl_base);
> +
> +	pcie->core_apb_rst = devm_reset_control_get(dev, "apb");
> +	if (IS_ERR(pcie->core_apb_rst)) {
> +		dev_err(dev, "Failed to get APB reset: %ld\n",
> +			PTR_ERR(pcie->core_apb_rst));
> +		return PTR_ERR(pcie->core_apb_rst);
> +	}
> +
> +	phys = devm_kcalloc(dev, pcie->phy_count, sizeof(*phys), GFP_KERNEL);
> +	if (!phys)
> +		return PTR_ERR(phys);
> +
> +	for (i = 0; i < pcie->phy_count; i++) {
> +		name = kasprintf(GFP_KERNEL, "p2u-%u", i);
> +		if (!name) {
> +			dev_err(dev, "Failed to create P2U string\n");
> +			return -ENOMEM;
> +		}
> +		phys[i] = devm_phy_get(dev, name);
> +		kfree(name);
> +		if (IS_ERR(phys[i])) {
> +			ret = PTR_ERR(phys[i]);
> +			dev_err(dev, "Failed to get PHY: %d\n", ret);
> +			return ret;
> +		}
> +	}
> +
> +	pcie->phys = phys;
> +
> +	dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
> +	if (!dbi_res) {
> +		dev_err(dev, "Failed to find \"dbi\" region\n");
> +		return PTR_ERR(dbi_res);
> +	}
> +	pcie->dbi_res = dbi_res;
> +
> +	pci->dbi_base = devm_ioremap_resource(dev, dbi_res);
> +	if (IS_ERR(pci->dbi_base))
> +		return PTR_ERR(pci->dbi_base);
> +
> +	/* Tegra HW locates DBI2 at a fixed offset from DBI */
> +	pci->dbi_base2 = pci->dbi_base + 0x1000;
> +
> +	atu_dma_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> +						   "atu_dma");
> +	if (!atu_dma_res) {
> +		dev_err(dev, "Failed to find \"atu_dma\" region\n");
> +		return PTR_ERR(atu_dma_res);
> +	}
> +	pcie->atu_dma_res = atu_dma_res;

Add an empty line.

I have just skimmed over it, I need more time to review the driver more
thoroughly, I will try to go over it tomorrow and we can see if we can
hit v5.3 but I can't guarantee anything, sorry but there was a
significant backlog on the PCI patch queue.

The rest of the series is fine but it is useless to merge it
without this patch so let's see how it goes.

Lorenzo

> +	pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);
> +	if (IS_ERR(pci->atu_base))
> +		return PTR_ERR(pci->atu_base);
> +
> +	pcie->core_rst = devm_reset_control_get(dev, "core");
> +	if (IS_ERR(pcie->core_rst)) {
> +		dev_err(dev, "Failed to get core reset: %ld\n",
> +			PTR_ERR(pcie->core_rst));
> +		return PTR_ERR(pcie->core_rst);
> +	}
> +
> +	pp->irq = platform_get_irq_byname(pdev, "intr");
> +	if (!pp->irq) {
> +		dev_err(dev, "Failed to get \"intr\" interrupt\n");
> +		return -ENODEV;
> +	}
> +
> +	ret = devm_request_irq(dev, pp->irq, tegra_pcie_irq_handler,
> +			       IRQF_SHARED, "tegra-pcie-intr", pcie);
> +	if (ret) {
> +		dev_err(dev, "Failed to request IRQ %d: %d\n", pp->irq, ret);
> +		return ret;
> +	}
> +
> +	pcie->bpmp = tegra_bpmp_get(dev);
> +	if (IS_ERR(pcie->bpmp))
> +		return PTR_ERR(pcie->bpmp);
> +
> +	platform_set_drvdata(pdev, pcie);
> +
> +	if (pcie->mode == DW_PCIE_RC_TYPE) {
> +		ret = tegra_pcie_config_rp(pcie);
> +		if (ret && ret != -ENOMEDIUM)
> +			goto fail;
> +		else
> +			return 0;
> +	}
> +
> +fail:
> +	tegra_bpmp_put(pcie->bpmp);
> +	return ret;
> +}
> +
> +static int tegra_pcie_dw_remove(struct platform_device *pdev)
> +{
> +	struct tegra_pcie_dw *pcie = platform_get_drvdata(pdev);
> +
> +	if (pcie->mode != DW_PCIE_RC_TYPE)
> +		return 0;
> +
> +	if (!pcie->link_state)
> +		return 0;
> +
> +	debugfs_remove_recursive(pcie->debugfs);
> +	tegra_pcie_deinit_controller(pcie);
> +	pm_runtime_put_sync(pcie->dev);
> +	pm_runtime_disable(pcie->dev);
> +	tegra_bpmp_put(pcie->bpmp);
> +
> +	return 0;
> +}
> +
> +static int tegra_pcie_dw_suspend_late(struct device *dev)
> +{
> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
> +	u32 val;
> +
> +	if (!pcie->link_state)
> +		return 0;
> +
> +	/* Enable HW_HOT_RST mode */
> +	val = appl_readl(pcie, APPL_CTRL);
> +	val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
> +		 APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
> +	val |= APPL_CTRL_HW_HOT_RST_EN;
> +	appl_writel(pcie, val, APPL_CTRL);
> +
> +	return 0;
> +}
> +
> +static int tegra_pcie_dw_suspend_noirq(struct device *dev)
> +{
> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
> +
> +	if (!pcie->link_state)
> +		return 0;
> +
> +	/* Save MSI interrupt vector */
> +	pcie->msi_ctrl_int = dw_pcie_readl_dbi(&pcie->pci,
> +					       PORT_LOGIC_MSI_CTRL_INT_0_EN);
> +	tegra_pcie_downstream_dev_to_D0(pcie);
> +	tegra_pcie_dw_pme_turnoff(pcie);
> +	return __deinit_controller(pcie);
> +}
> +
> +static int tegra_pcie_dw_resume_noirq(struct device *dev)
> +{
> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
> +	int ret;
> +
> +	if (!pcie->link_state)
> +		return 0;
> +
> +	ret = tegra_pcie_config_controller(pcie, true);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = tegra_pcie_dw_host_init(&pcie->pci.pp);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to init host: %d\n", ret);
> +		goto fail_host_init;
> +	}
> +
> +	/* Restore MSI interrupt vector */
> +	dw_pcie_writel_dbi(&pcie->pci, PORT_LOGIC_MSI_CTRL_INT_0_EN,
> +			   pcie->msi_ctrl_int);
> +
> +	return 0;
> +fail_host_init:
> +	return __deinit_controller(pcie);
> +}
> +
> +static int tegra_pcie_dw_resume_early(struct device *dev)
> +{
> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
> +	u32 val;
> +
> +	if (!pcie->link_state)
> +		return 0;
> +
> +	/* Disable HW_HOT_RST mode */
> +	val = appl_readl(pcie, APPL_CTRL);
> +	val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
> +		 APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
> +	val |= APPL_CTRL_HW_HOT_RST_MODE_IMDT_RST <<
> +	       APPL_CTRL_HW_HOT_RST_MODE_SHIFT;
> +	val &= ~APPL_CTRL_HW_HOT_RST_EN;
> +	appl_writel(pcie, val, APPL_CTRL);
> +
> +	return 0;
> +}
> +
> +static void tegra_pcie_dw_shutdown(struct platform_device *pdev)
> +{
> +	struct tegra_pcie_dw *pcie = platform_get_drvdata(pdev);
> +
> +	if (pcie->mode != DW_PCIE_RC_TYPE)
> +		return;
> +
> +	if (!pcie->link_state)
> +		return;
> +
> +	debugfs_remove_recursive(pcie->debugfs);
> +	tegra_pcie_downstream_dev_to_D0(pcie);
> +
> +	disable_irq(pcie->pci.pp.irq);
> +	if (IS_ENABLED(CONFIG_PCI_MSI))
> +		disable_irq(pcie->pci.pp.msi_irq);
> +
> +	tegra_pcie_dw_pme_turnoff(pcie);
> +	__deinit_controller(pcie);
> +}
> +
> +static const struct dev_pm_ops tegra_pcie_dw_pm_ops = {
> +	.suspend_late = tegra_pcie_dw_suspend_late,
> +	.suspend_noirq = tegra_pcie_dw_suspend_noirq,
> +	.resume_noirq = tegra_pcie_dw_resume_noirq,
> +	.resume_early = tegra_pcie_dw_resume_early,
> +};
> +
> +static struct platform_driver tegra_pcie_dw_driver = {
> +	.probe = tegra_pcie_dw_probe,
> +	.remove = tegra_pcie_dw_remove,
> +	.shutdown = tegra_pcie_dw_shutdown,
> +	.driver = {
> +		.name	= "tegra194-pcie",
> +		.pm = &tegra_pcie_dw_pm_ops,
> +		.of_match_table = tegra_pcie_dw_of_match,
> +	},
> +};
> +module_platform_driver(tegra_pcie_dw_driver);
> +
> +MODULE_AUTHOR("Vidya Sagar <vidyas@nvidia.com>");
> +MODULE_DESCRIPTION("NVIDIA PCIe host controller driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.17.1
>

On 7/10/2019 10:32 PM, Lorenzo Pieralisi wrote:
> On Wed, Jul 10, 2019 at 11:52:12AM +0530, Vidya Sagar wrote:
> 
> [...]
> 
>> +#if defined(CONFIG_PCIEASPM)
>> +static void disable_aspm_l11(struct tegra_pcie_dw *pcie)
>> +{
>> +	u32 val;
>> +
>> +	val = dw_pcie_readl_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub);
>> +	val &= ~PCI_L1SS_CAP_ASPM_L1_1;
>> +	dw_pcie_writel_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub, val);
>> +}
>> +
>> +static void disable_aspm_l12(struct tegra_pcie_dw *pcie)
>> +{
>> +	u32 val;
>> +
>> +	val = dw_pcie_readl_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub);
>> +	val &= ~PCI_L1SS_CAP_ASPM_L1_2;
>> +	dw_pcie_writel_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub, val);
>> +}
>> +
>> +static inline u32 event_counter_prog(struct tegra_pcie_dw *pcie, u32 event)
>> +{
>> +	u32 val;
>> +
>> +	val = dw_pcie_readl_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid]);
>> +	val &= ~(EVENT_COUNTER_EVENT_SEL_MASK << EVENT_COUNTER_EVENT_SEL_SHIFT);
>> +	val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
>> +	val |= event << EVENT_COUNTER_EVENT_SEL_SHIFT;
>> +	val |= EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
>> +	dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid], val);
>> +	val = dw_pcie_readl_dbi(&pcie->pci, event_cntr_data_offset[pcie->cid]);
>> +	return val;
>> +}
>> +
>> +static int aspm_state_cnt(struct seq_file *s, void *data)
>> +{
>> +	struct tegra_pcie_dw *pcie = (struct tegra_pcie_dw *)
>> +				     dev_get_drvdata(s->private);
>> +	u32 val;
>> +
>> +	seq_printf(s, "Tx L0s entry count : %u\n",
>> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_Tx_L0S));
>> +
>> +	seq_printf(s, "Rx L0s entry count : %u\n",
>> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_Rx_L0S));
>> +
>> +	seq_printf(s, "Link L1 entry count : %u\n",
>> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1));
>> +
>> +	seq_printf(s, "Link L1.1 entry count : %u\n",
>> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1_1));
>> +
>> +	seq_printf(s, "Link L1.2 entry count : %u\n",
>> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1_2));
>> +
>> +	/* Clear all counters */
>> +	dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid],
>> +			   EVENT_COUNTER_ALL_CLEAR);
>> +
>> +	/* Re-enable counting */
>> +	val = EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
>> +	val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
>> +	dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid], val);
>> +
>> +	return 0;
>> +}
>> +#endif
>> +
>> +static int init_debugfs(struct tegra_pcie_dw *pcie)
>> +{
>> +#if defined(CONFIG_PCIEASPM)
>> +	struct dentry *d;
>> +
>> +	d = debugfs_create_devm_seqfile(pcie->dev, "aspm_state_cnt",
>> +					pcie->debugfs, aspm_state_cnt);
>> +	if (IS_ERR_OR_NULL(d))
>> +		dev_err(pcie->dev,
>> +			"Failed to create debugfs file \"aspm_state_cnt\"\n");
>> +#endif
>> +	return 0;
>> +}
> 
> I prefer writing it:
> 
> #if defined(CONFIG_PCIEASPM)
> static void disable_aspm_l11(struct tegra_pcie_dw *pcie)
> {
> ...
> }
> 
> static void disable_aspm_l12(struct tegra_pcie_dw *pcie)
> {
> ...
> }
> 
> static inline u32 event_counter_prog(struct tegra_pcie_dw *pcie, u32 event)
> {
> ...
> }
> 
> static int aspm_state_cnt(struct seq_file *s, void *data)
> {
> ...
> }
> 
> static int init_debugfs(struct tegra_pcie_dw *pcie)
> {
> 	struct dentry *d;
> 
> 	d = debugfs_create_devm_seqfile(pcie->dev, "aspm_state_cnt",
> 					pcie->debugfs, aspm_state_cnt);
> 	if (IS_ERR_OR_NULL(d))
> 		dev_err(pcie->dev,
> 			"Failed to create debugfs file \"aspm_state_cnt\"\n");
> 	return 0;
> }
> #else
> static inline int init_debugfs(struct tegra_pcie_dw *pcie) { return 0; }
> #endif
I'll address it in the next patch.

> 
>> +
>> +static void tegra_pcie_enable_system_interrupts(struct pcie_port *pp)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
>> +	u32 val;
>> +	u16 val_w;
>> +
>> +	val = appl_readl(pcie, APPL_INTR_EN_L0_0);
>> +	val |= APPL_INTR_EN_L0_0_LINK_STATE_INT_EN;
>> +	appl_writel(pcie, val, APPL_INTR_EN_L0_0);
>> +
>> +	val = appl_readl(pcie, APPL_INTR_EN_L1_0_0);
>> +	val |= APPL_INTR_EN_L1_0_0_LINK_REQ_RST_NOT_INT_EN;
>> +	appl_writel(pcie, val, APPL_INTR_EN_L1_0_0);
>> +
>> +	if (pcie->enable_cdm_check) {
>> +		val = appl_readl(pcie, APPL_INTR_EN_L0_0);
>> +		val |= APPL_INTR_EN_L0_0_CDM_REG_CHK_INT_EN;
>> +		appl_writel(pcie, val, APPL_INTR_EN_L0_0);
>> +
>> +		val = appl_readl(pcie, APPL_INTR_EN_L1_18);
>> +		val |= APPL_INTR_EN_L1_18_CDM_REG_CHK_CMP_ERR;
>> +		val |= APPL_INTR_EN_L1_18_CDM_REG_CHK_LOGIC_ERR;
>> +		appl_writel(pcie, val, APPL_INTR_EN_L1_18);
>> +	}
>> +
>> +	val_w = dw_pcie_readw_dbi(&pcie->pci, pcie->pcie_cap_base +
>> +				  PCI_EXP_LNKSTA);
>> +	pcie->init_link_width = (val_w & PCI_EXP_LNKSTA_NLW) >>
>> +				PCI_EXP_LNKSTA_NLW_SHIFT;
>> +
>> +	val_w = dw_pcie_readw_dbi(&pcie->pci, pcie->pcie_cap_base +
>> +				  PCI_EXP_LNKCTL);
>> +	val_w |= PCI_EXP_LNKCTL_LBMIE;
>> +	dw_pcie_writew_dbi(&pcie->pci, pcie->pcie_cap_base + PCI_EXP_LNKCTL,
>> +			   val_w);
>> +}
>> +
>> +static void tegra_pcie_enable_legacy_interrupts(struct pcie_port *pp)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
>> +	u32 val;
>> +
>> +	/* Enable legacy interrupt generation */
>> +	val = appl_readl(pcie, APPL_INTR_EN_L0_0);
>> +	val |= APPL_INTR_EN_L0_0_SYS_INTR_EN;
>> +	val |= APPL_INTR_EN_L0_0_INT_INT_EN;
>> +	appl_writel(pcie, val, APPL_INTR_EN_L0_0);
>> +
>> +	val = appl_readl(pcie, APPL_INTR_EN_L1_8_0);
>> +	val |= APPL_INTR_EN_L1_8_INTX_EN;
>> +	val |= APPL_INTR_EN_L1_8_AUTO_BW_INT_EN;
>> +	val |= APPL_INTR_EN_L1_8_BW_MGT_INT_EN;
>> +	if (IS_ENABLED(CONFIG_PCIEAER))
>> +		val |= APPL_INTR_EN_L1_8_AER_INT_EN;
>> +	appl_writel(pcie, val, APPL_INTR_EN_L1_8_0);
>> +}
>> +
>> +static void tegra_pcie_enable_msi_interrupts(struct pcie_port *pp)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
>> +	u32 val;
>> +
>> +	dw_pcie_msi_init(pp);
>> +
>> +	/* Enable MSI interrupt generation */
>> +	val = appl_readl(pcie, APPL_INTR_EN_L0_0);
>> +	val |= APPL_INTR_EN_L0_0_SYS_MSI_INTR_EN;
>> +	val |= APPL_INTR_EN_L0_0_MSI_RCV_INT_EN;
>> +	appl_writel(pcie, val, APPL_INTR_EN_L0_0);
>> +}
>> +
>> +static void tegra_pcie_enable_interrupts(struct pcie_port *pp)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
>> +
>> +	/* Clear interrupt statuses before enabling interrupts */
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L0);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_0_0);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_1);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_2);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_3);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_6);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_7);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_8_0);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_9);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_10);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_11);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_13);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_14);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_15);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_17);
>> +
>> +	tegra_pcie_enable_system_interrupts(pp);
>> +	tegra_pcie_enable_legacy_interrupts(pp);
>> +	if (IS_ENABLED(CONFIG_PCI_MSI))
>> +		tegra_pcie_enable_msi_interrupts(pp);
>> +}
>> +
>> +static void config_gen3_gen4_eq_presets(struct tegra_pcie_dw *pcie)
>> +{
>> +	struct dw_pcie *pci = &pcie->pci;
>> +	u32 val, offset, i;
>> +
>> +	/* Program init preset */
>> +	for (i = 0; i < pcie->num_lanes; i++) {
>> +		dw_pcie_read(pci->dbi_base + CAP_SPCIE_CAP_OFF
>> +				 + (i * 2), 2, &val);
>> +		val &= ~CAP_SPCIE_CAP_OFF_DSP_TX_PRESET0_MASK;
>> +		val |= GEN3_GEN4_EQ_PRESET_INIT;
>> +		val &= ~CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_MASK;
>> +		val |= (GEN3_GEN4_EQ_PRESET_INIT <<
>> +			   CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_SHIFT);
>> +		dw_pcie_write(pci->dbi_base + CAP_SPCIE_CAP_OFF
>> +				 + (i * 2), 2, val);
>> +
>> +		offset = dw_pcie_find_ext_capability(pci,
>> +						     PCI_EXT_CAP_ID_PL_16GT) +
>> +				PCI_PL_16GT_LE_CTRL;
>> +		dw_pcie_read(pci->dbi_base + offset + i, 1, &val);
>> +		val &= ~PCI_PL_16GT_LE_CTRL_DSP_TX_PRESET_MASK;
>> +		val |= GEN3_GEN4_EQ_PRESET_INIT;
>> +		val &= ~PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_MASK;
>> +		val |= (GEN3_GEN4_EQ_PRESET_INIT <<
>> +			PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_SHIFT);
>> +		dw_pcie_write(pci->dbi_base + offset + i, 1, val);
>> +	}
>> +
>> +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
>> +	val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
>> +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
>> +
>> +	val = dw_pcie_readl_dbi(pci, GEN3_EQ_CONTROL_OFF);
>> +	val &= ~GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK;
>> +	val |= (0x3ff << GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_SHIFT);
>> +	val &= ~GEN3_EQ_CONTROL_OFF_FB_MODE_MASK;
>> +	dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, val);
>> +
>> +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
>> +	val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
>> +	val |= (0x1 << GEN3_RELATED_OFF_RATE_SHADOW_SEL_SHIFT);
>> +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
>> +
>> +	val = dw_pcie_readl_dbi(pci, GEN3_EQ_CONTROL_OFF);
>> +	val &= ~GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK;
>> +	val |= (0x360 << GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_SHIFT);
>> +	val &= ~GEN3_EQ_CONTROL_OFF_FB_MODE_MASK;
>> +	dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, val);
>> +
>> +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
>> +	val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
>> +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
>> +}
>> +
>> +static int tegra_pcie_dw_host_init(struct pcie_port *pp)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
>> +	u32 val, tmp, offset, speed;
>> +	unsigned int count;
>> +	u16 val_w;
>> +
>> +core_init:
> 
> Why should we restart from here ? What's the effect of the reset
> on following registers set-up ?
before jumping to 'core_init' label, PCIe IP core is put through reset cycle and
registers in the core get their default values and hence need to be programmed again.

> 
>> +	count = 200;
>> +#if defined(CONFIG_PCIEASPM)
>> +	offset = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_L1SS);
>> +	pcie->cfg_link_cap_l1sub = offset + PCI_L1SS_CAP;
>> +#endif
> 
> Can we group it in the #ifdef above ?
I'll address it in the next patch.

> 
>> +	val = dw_pcie_readl_dbi(pci, PCI_IO_BASE);
>> +	val &= ~(IO_BASE_IO_DECODE | IO_BASE_IO_DECODE_BIT8);
>> +	dw_pcie_writel_dbi(pci, PCI_IO_BASE, val);
>> +
>> +	val = dw_pcie_readl_dbi(pci, PCI_PREF_MEMORY_BASE);
>> +	val |= CFG_PREF_MEM_LIMIT_BASE_MEM_DECODE;
>> +	val |= CFG_PREF_MEM_LIMIT_BASE_MEM_LIMIT_DECODE;
>> +	dw_pcie_writel_dbi(pci, PCI_PREF_MEMORY_BASE, val);
>> +
>> +	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 0);
>> +
>> +	/* Configure FTS */
>> +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL);
>> +	val &= ~(N_FTS_MASK << N_FTS_SHIFT);
>> +	val |= N_FTS_VAL << N_FTS_SHIFT;
>> +	dw_pcie_writel_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL, val);
>> +
>> +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_GEN2_CTRL);
>> +	val &= ~FTS_MASK;
>> +	val |= FTS_VAL;
>> +	dw_pcie_writel_dbi(pci, PORT_LOGIC_GEN2_CTRL, val);
>> +
>> +	/* Enable as 0xFFFF0001 response for CRS */
>> +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT);
>> +	val &= ~(AMBA_ERROR_RESPONSE_CRS_MASK << AMBA_ERROR_RESPONSE_CRS_SHIFT);
>> +	val |= (AMBA_ERROR_RESPONSE_CRS_OKAY_FFFF0001 <<
>> +		AMBA_ERROR_RESPONSE_CRS_SHIFT);
>> +	dw_pcie_writel_dbi(pci, PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT, val);
>> +
>> +	/* Configure Max Speed from DT */
>> +	if (pcie->max_speed && pcie->max_speed != -EINVAL) {
>> +		val = dw_pcie_readl_dbi(pci, pcie->pcie_cap_base +
>> +					PCI_EXP_LNKCAP);
>> +		val &= ~PCI_EXP_LNKCAP_SLS;
>> +		val |= pcie->max_speed;
>> +		dw_pcie_writel_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP,
>> +				   val);
>> +	}
>> +
>> +	/* Configure Max lane width from DT */
>> +	val = dw_pcie_readl_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP);
>> +	val &= ~PCI_EXP_LNKCAP_MLW;
>> +	val |= (pcie->num_lanes << PCI_EXP_LNKSTA_NLW_SHIFT);
>> +	dw_pcie_writel_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP, val);
>> +
>> +	config_gen3_gen4_eq_presets(pcie);
>> +
>> +#if defined(CONFIG_PCIEASPM)
>> +	/* Enable ASPM counters */
>> +	val = EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
>> +	val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
>> +	dw_pcie_writel_dbi(pci, event_cntr_ctrl_offset[pcie->cid], val);
>> +
>> +	/* Program T_cmrt and T_pwr_on values */
>> +	val = dw_pcie_readl_dbi(pci, pcie->cfg_link_cap_l1sub);
>> +	val &= ~(PCI_L1SS_CAP_CM_RESTORE_TIME | PCI_L1SS_CAP_P_PWR_ON_VALUE);
>> +	val |= (pcie->aspm_cmrt << 8);
>> +	val |= (pcie->aspm_pwr_on_t << 19);
>> +	dw_pcie_writel_dbi(pci, pcie->cfg_link_cap_l1sub, val);
>> +
>> +	/* Program L0s and L1 entrance latencies */
>> +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL);
>> +	val &= ~L0S_ENTRANCE_LAT_MASK;
>> +	val |= (pcie->aspm_l0s_enter_lat << L0S_ENTRANCE_LAT_SHIFT);
>> +	val |= ENTER_ASPM;
>> +	dw_pcie_writel_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL, val);
>> +#endif
> 
> It would be good to group all init guarded in CONFIG_PCIEASPM in
> one function and related ifdef guard.
> 
>> +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
>> +	val &= ~GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL;
>> +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
>> +
>> +	if (pcie->update_fc_fixup) {
>> +		val = dw_pcie_readl_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF);
>> +		val |= 0x1 << CFG_TIMER_CTRL_ACK_NAK_SHIFT;
>> +		dw_pcie_writel_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF, val);
>> +	}
>> +
>> +	dw_pcie_setup_rc(pp);
>> +
>> +	clk_set_rate(pcie->core_clk, GEN4_CORE_CLK_FREQ);
>> +
>> +	/* Assert RST */
>> +	val = appl_readl(pcie, APPL_PINMUX);
>> +	val &= ~APPL_PINMUX_PEX_RST;
>> +	appl_writel(pcie, val, APPL_PINMUX);
> 
> What's the effect of this RST on the registers programmed above ?
This register is software interface to toggle PERST sideband signal going to
downstream devices. Nothing happens to the registers programmed above because
of applying fundamental reset to downstream devices.

> 
>> +	usleep_range(100, 200);
>> +
>> +	/* Enable LTSSM */
>> +	val = appl_readl(pcie, APPL_CTRL);
>> +	val |= APPL_CTRL_LTSSM_EN;
>> +	appl_writel(pcie, val, APPL_CTRL);
>> +
>> +	/* De-assert RST */
>> +	val = appl_readl(pcie, APPL_PINMUX);
>> +	val |= APPL_PINMUX_PEX_RST;
>> +	appl_writel(pcie, val, APPL_PINMUX);
>> +
>> +	msleep(100);
>> +
>> +	val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
>> +	while (!(val_w & PCI_EXP_LNKSTA_DLLLA)) {
>> +		if (count) {
>> +			dev_dbg(pci->dev, "Waiting for link up\n");
>> +			usleep_range(1000, 2000);
>> +			val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
>> +						  PCI_EXP_LNKSTA);
>> +			count--;
>> +			continue;
>> +		}
>> +
>> +		val = appl_readl(pcie, APPL_DEBUG);
>> +		val &= APPL_DEBUG_LTSSM_STATE_MASK;
>> +		val >>= APPL_DEBUG_LTSSM_STATE_SHIFT;
>> +		tmp = appl_readl(pcie, APPL_LINK_STATUS);
>> +		tmp &= APPL_LINK_STATUS_RDLH_LINK_UP;
>> +		if (!(val == 0x11 && !tmp)) {
>> +			dev_info(pci->dev, "Link is down\n");
>> +			return 0;
>> +		}
>> +
>> +		dev_info(pci->dev, "Link is down in DLL");
>> +		dev_info(pci->dev, "Trying again with DLFE disabled\n");
>> +		/* Disable LTSSM */
>> +		val = appl_readl(pcie, APPL_CTRL);
>> +		val &= ~APPL_CTRL_LTSSM_EN;
>> +		appl_writel(pcie, val, APPL_CTRL);
>> +
>> +		reset_control_assert(pcie->core_rst);
>> +		reset_control_deassert(pcie->core_rst);
>> +
>> +		offset = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_DLF);
>> +		val = dw_pcie_readl_dbi(pci, offset + PCI_DLF_CAP);
>> +		val &= ~PCI_DLF_EXCHANGE_ENABLE;
>> +		dw_pcie_writel_dbi(pci, offset, val);
>> +
>> +		/* Retry now with DLF Exchange disabled */
>> +		goto core_init;
> 
> See above.
> 
>> +	}
>> +	dev_dbg(pci->dev, "Link is up\n");
>> +
>> +	speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
>> +		PCI_EXP_LNKSTA_CLS;
>> +	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
>> +
>> +	tegra_pcie_enable_interrupts(pp);
>> +
>> +	return 0;
>> +}
>> +
>> +static int tegra_pcie_dw_link_up(struct dw_pcie *pci)
>> +{
>> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
>> +	u32 val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
>> +
>> +	return !!(val & PCI_EXP_LNKSTA_DLLLA);
>> +}
>> +
>> +static void tegra_pcie_set_msi_vec_num(struct pcie_port *pp)
>> +{
>> +	pp->num_vectors = MAX_MSI_IRQS;
>> +}
>> +
>> +static const struct dw_pcie_ops tegra_dw_pcie_ops = {
>> +	.link_up = tegra_pcie_dw_link_up,
>> +};
>> +
>> +static struct dw_pcie_host_ops tegra_pcie_dw_host_ops = {
>> +	.rd_own_conf = tegra_pcie_dw_rd_own_conf,
>> +	.wr_own_conf = tegra_pcie_dw_wr_own_conf,
>> +	.host_init = tegra_pcie_dw_host_init,
>> +	.set_num_vectors = tegra_pcie_set_msi_vec_num,
>> +};
>> +
>> +static void tegra_pcie_disable_phy(struct tegra_pcie_dw *pcie)
>> +{
>> +	unsigned int phy_count = pcie->phy_count;
>> +
>> +	while (phy_count--) {
>> +		phy_power_off(pcie->phys[phy_count]);
>> +		phy_exit(pcie->phys[phy_count]);
>> +	}
>> +}
>> +
>> +static int tegra_pcie_enable_phy(struct tegra_pcie_dw *pcie)
>> +{
>> +	unsigned int i;
>> +	int ret;
>> +
>> +	for (i = 0; i < pcie->phy_count; i++) {
>> +		ret = phy_init(pcie->phys[i]);
>> +		if (ret < 0)
>> +			goto phy_power_off;
>> +
>> +		ret = phy_power_on(pcie->phys[i]);
>> +		if (ret < 0)
>> +			goto phy_exit;
>> +	}
>> +
>> +	return 0;
>> +
>> +phy_power_off:
>> +	while (i--) {
>> +		phy_power_off(pcie->phys[i]);
>> +phy_exit:
>> +		phy_exit(pcie->phys[i]);
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static int tegra_pcie_dw_parse_dt(struct tegra_pcie_dw *pcie)
>> +{
>> +	struct device_node *np = pcie->dev->of_node;
>> +	int ret;
>> +
>> +	ret = of_property_read_u32(np, "nvidia,aspm-cmrt-us", &pcie->aspm_cmrt);
>> +	if (ret < 0) {
>> +		dev_info(pcie->dev, "Failed to read ASPM T_cmrt: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	ret = of_property_read_u32(np, "nvidia,aspm-pwr-on-t-us",
>> +				   &pcie->aspm_pwr_on_t);
>> +	if (ret < 0)
>> +		dev_info(pcie->dev, "Failed to read ASPM Power On time: %d\n",
>> +			 ret);
>> +
>> +	ret = of_property_read_u32(np, "nvidia,aspm-l0s-entrance-latency-us",
>> +				   &pcie->aspm_l0s_enter_lat);
>> +	if (ret < 0)
>> +		dev_info(pcie->dev,
>> +			 "Failed to read ASPM L0s Entrance latency: %d\n", ret);
>> +
>> +	ret = of_property_read_u32(np, "num-lanes", &pcie->num_lanes);
>> +	if (ret < 0) {
>> +		dev_err(pcie->dev, "Failed to read num-lanes: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	pcie->max_speed = of_pci_get_max_link_speed(np);
>> +
>> +	ret = of_property_read_u32_index(np, "nvidia,bpmp", 1, &pcie->cid);
>> +	if (ret) {
>> +		dev_err(pcie->dev, "Failed to read Controller-ID: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	pcie->phy_count = of_property_count_strings(np, "phy-names");
>> +	if (pcie->phy_count < 0) {
>> +		dev_err(pcie->dev, "Failed to find PHY entries: %d\n",
>> +			pcie->phy_count);
>> +		return pcie->phy_count;
>> +	}
>> +
>> +	if (of_property_read_bool(np, "nvidia,update-fc-fixup"))
>> +		pcie->update_fc_fixup = true;
>> +
>> +	pcie->supports_clkreq =
>> +		of_property_read_bool(pcie->dev->of_node, "supports-clkreq");
>> +
>> +	pcie->enable_cdm_check =
>> +		of_property_read_bool(np, "snps,enable-cdm-check");
>> +
>> +	return 0;
>> +}
>> +
>> +static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
>> +					  bool enable)
>> +{
>> +	struct mrq_uphy_response resp;
>> +	struct tegra_bpmp_message msg;
>> +	struct mrq_uphy_request req;
>> +	int err;
>> +
>> +	if (pcie->cid == 5)
>> +		return 0;
>> +
>> +	memset(&req, 0, sizeof(req));
>> +	memset(&resp, 0, sizeof(resp));
>> +
>> +	req.cmd = CMD_UPHY_PCIE_CONTROLLER_STATE;
>> +	req.controller_state.pcie_controller = pcie->cid;
>> +	req.controller_state.enable = enable;
>> +
>> +	memset(&msg, 0, sizeof(msg));
>> +	msg.mrq = MRQ_UPHY;
>> +	msg.tx.data = &req;
>> +	msg.tx.size = sizeof(req);
>> +	msg.rx.data = &resp;
>> +	msg.rx.size = sizeof(resp);
>> +
>> +	if (irqs_disabled())
>> +		err = tegra_bpmp_transfer_atomic(pcie->bpmp, &msg);
>> +	else
>> +		err = tegra_bpmp_transfer(pcie->bpmp, &msg);
>> +
>> +	return err;
>> +}
>> +
>> +static void tegra_pcie_downstream_dev_to_D0(struct tegra_pcie_dw *pcie)
>> +{
>> +	struct pcie_port *pp = &pcie->pci.pp;
>> +	struct pci_dev *pdev;
>> +	struct pci_bus *child;
>> +
>> +	list_for_each_entry(child, &pp->root_bus->children, node) {
>> +		/* Bring downstream devices to D0 if they are not already in */
>> +		if (child->parent == pp->root_bus)
>> +			break;
>> +	}
>> +	list_for_each_entry(pdev, &child->devices, bus_list) {
>> +		if (PCI_SLOT(pdev->devfn) == 0) {
>> +			if (pci_set_power_state(pdev, PCI_D0))
>> +				dev_err(pcie->dev,
>> +					"Failed to transition %s to D0 state\n",
>> +					dev_name(&pdev->dev));
>> +		}
>> +	}
>> +}
>> +
>> +static int tegra_pcie_config_controller(struct tegra_pcie_dw *pcie,
>> +					bool en_hw_hot_rst)
>> +{
>> +	int ret;
>> +	u32 val;
>> +
>> +	ret = tegra_pcie_bpmp_set_ctrl_state(pcie, true);
>> +	if (ret) {
>> +		dev_err(pcie->dev,
>> +			"Failed to enable controller %u: %d\n", pcie->cid, ret);
>> +		return ret;
>> +	}
>> +
>> +	ret = regulator_enable(pcie->pex_ctl_supply);
>> +	if (ret < 0) {
>> +		dev_err(pcie->dev, "Failed to enable regulator: %d\n", ret);
>> +		goto fail_reg_en;
>> +	}
>> +
>> +	ret = clk_prepare_enable(pcie->core_clk);
>> +	if (ret) {
>> +		dev_err(pcie->dev, "Failed to enable core clock: %d\n", ret);
>> +		goto fail_core_clk;
>> +	}
>> +
>> +	ret = reset_control_deassert(pcie->core_apb_rst);
>> +	if (ret) {
>> +		dev_err(pcie->dev, "Failed to deassert core APB reset: %d\n",
>> +			ret);
>> +		goto fail_core_apb_rst;
>> +	}
>> +
>> +	if (en_hw_hot_rst) {
>> +		/* Enable HW_HOT_RST mode */
>> +		val = appl_readl(pcie, APPL_CTRL);
>> +		val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
>> +			 APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
>> +		val |= APPL_CTRL_HW_HOT_RST_EN;
>> +		appl_writel(pcie, val, APPL_CTRL);
>> +	}
>> +
>> +	ret = tegra_pcie_enable_phy(pcie);
>> +	if (ret) {
>> +		dev_err(pcie->dev, "Failed to enable PHY: %d\n", ret);
>> +		goto fail_phy;
>> +	}
>> +
>> +	/* Update CFG base address */
>> +	appl_writel(pcie, pcie->dbi_res->start & APPL_CFG_BASE_ADDR_MASK,
>> +		    APPL_CFG_BASE_ADDR);
>> +
>> +	/* Configure this core for RP mode operation */
>> +	appl_writel(pcie, APPL_DM_TYPE_RP, APPL_DM_TYPE);
>> +
>> +	appl_writel(pcie, 0x0, APPL_CFG_SLCG_OVERRIDE);
>> +
>> +	val = appl_readl(pcie, APPL_CTRL);
>> +	appl_writel(pcie, val | APPL_CTRL_SYS_PRE_DET_STATE, APPL_CTRL);
>> +
>> +	val = appl_readl(pcie, APPL_CFG_MISC);
>> +	val |= (APPL_CFG_MISC_ARCACHE_VAL << APPL_CFG_MISC_ARCACHE_SHIFT);
>> +	appl_writel(pcie, val, APPL_CFG_MISC);
>> +
>> +	if (!pcie->supports_clkreq) {
>> +		val = appl_readl(pcie, APPL_PINMUX);
>> +		val |= APPL_PINMUX_CLKREQ_OUT_OVRD_EN;
>> +		val |= APPL_PINMUX_CLKREQ_OUT_OVRD;
>> +		appl_writel(pcie, val, APPL_PINMUX);
>> +	}
>> +
>> +	/* Update iATU_DMA base address */
>> +	appl_writel(pcie,
>> +		    pcie->atu_dma_res->start & APPL_CFG_IATU_DMA_BASE_ADDR_MASK,
>> +		    APPL_CFG_IATU_DMA_BASE_ADDR);
>> +
>> +	reset_control_deassert(pcie->core_rst);
>> +
>> +	pcie->pcie_cap_base = dw_pcie_find_capability(&pcie->pci,
>> +						      PCI_CAP_ID_EXP);
>> +
>> +#if defined(CONFIG_PCIEASPM)
>> +	/* Disable ASPM-L1SS advertisement as there is no CLKREQ routing */
>> +	if (!pcie->supports_clkreq) {
>> +		disable_aspm_l11(pcie);
>> +		disable_aspm_l12(pcie);
>> +	}
>> +#endif
>> +	return ret;
>> +
>> +fail_phy:
>> +	reset_control_assert(pcie->core_apb_rst);
>> +fail_core_apb_rst:
>> +	clk_disable_unprepare(pcie->core_clk);
>> +fail_core_clk:
>> +	regulator_disable(pcie->pex_ctl_supply);
>> +fail_reg_en:
>> +	tegra_pcie_bpmp_set_ctrl_state(pcie, false);
>> +
>> +	return ret;
>> +}
>> +
>> +static int __deinit_controller(struct tegra_pcie_dw *pcie)
>> +{
>> +	int ret;
>> +
>> +	ret = reset_control_assert(pcie->core_rst);
>> +	if (ret) {
>> +		dev_err(pcie->dev, "Failed to assert \"core\" reset: %d\n",
>> +			ret);
>> +		return ret;
>> +	}
>> +	tegra_pcie_disable_phy(pcie);
>> +	ret = reset_control_assert(pcie->core_apb_rst);
>> +	if (ret) {
>> +		dev_err(pcie->dev, "Failed to assert APB reset: %d\n", ret);
>> +		return ret;
>> +	}
>> +	clk_disable_unprepare(pcie->core_clk);
>> +	ret = regulator_disable(pcie->pex_ctl_supply);
>> +	if (ret) {
>> +		dev_err(pcie->dev, "Failed to disable regulator: %d\n", ret);
>> +		return ret;
>> +	}
>> +	ret = tegra_pcie_bpmp_set_ctrl_state(pcie, false);
>> +	if (ret) {
>> +		dev_err(pcie->dev, "Failed to disable controller %d: %d\n",
>> +			pcie->cid, ret);
>> +		return ret;
>> +	}
>> +	return ret;
>> +}
>> +
>> +static int tegra_pcie_init_controller(struct tegra_pcie_dw *pcie)
>> +{
>> +	struct dw_pcie *pci = &pcie->pci;
>> +	struct pcie_port *pp = &pci->pp;
>> +	int ret;
>> +
>> +	ret = tegra_pcie_config_controller(pcie, false);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	pp->root_bus_nr = -1;
> 
> Useless, drop it, it is initialized in dw_pcie_host_init().
Ok.

> 
>> +	pp->ops = &tegra_pcie_dw_host_ops;
>> +
>> +	ret = dw_pcie_host_init(pp);
>> +	if (ret < 0) {
>> +		dev_err(pcie->dev, "Failed to add PCIe port: %d\n", ret);
>> +		goto fail_host_init;
>> +	}
>> +
>> +	return 0;
>> +
>> +fail_host_init:
>> +	return __deinit_controller(pcie);
>> +}
>> +
>> +static int tegra_pcie_try_link_l2(struct tegra_pcie_dw *pcie)
>> +{
>> +	u32 val;
>> +
>> +	if (!tegra_pcie_dw_link_up(&pcie->pci))
>> +		return 0;
>> +
>> +	val = appl_readl(pcie, APPL_RADM_STATUS);
>> +	val |= APPL_PM_XMT_TURNOFF_STATE;
>> +	appl_writel(pcie, val, APPL_RADM_STATUS);
>> +
>> +	return readl_poll_timeout_atomic(pcie->appl_base + APPL_DEBUG, val,
>> +				 val & APPL_DEBUG_PM_LINKST_IN_L2_LAT,
>> +				 1, PME_ACK_TIMEOUT);
>> +}
>> +
>> +static void tegra_pcie_dw_pme_turnoff(struct tegra_pcie_dw *pcie)
>> +{
>> +	u32 data;
>> +	int err;
>> +
>> +	if (!tegra_pcie_dw_link_up(&pcie->pci)) {
>> +		dev_dbg(pcie->dev, "PCIe link is not up...!\n");
>> +		return;
>> +	}
>> +
>> +	if (tegra_pcie_try_link_l2(pcie)) {
>> +		dev_info(pcie->dev, "Link didn't transition to L2 state\n");
>> +		/*
>> +		 * TX lane clock freq will reset to Gen1 only if link is in L2
>> +		 * or detect state.
>> +		 * So apply pex_rst to end point to force RP to go into detect
>> +		 * state
>> +		 */
>> +		data = appl_readl(pcie, APPL_PINMUX);
>> +		data &= ~APPL_PINMUX_PEX_RST;
>> +		appl_writel(pcie, data, APPL_PINMUX);
>> +
>> +		err = readl_poll_timeout_atomic(pcie->appl_base + APPL_DEBUG,
>> +						data,
>> +						((data &
>> +						APPL_DEBUG_LTSSM_STATE_MASK) >>
>> +						APPL_DEBUG_LTSSM_STATE_SHIFT) ==
>> +						LTSSM_STATE_PRE_DETECT,
>> +						1, LTSSM_TIMEOUT);
>> +		if (err) {
>> +			dev_info(pcie->dev, "Link didn't go to detect state\n");
>> +		} else {
>> +			/* Disable LTSSM after link is in detect state */
>> +			data = appl_readl(pcie, APPL_CTRL);
>> +			data &= ~APPL_CTRL_LTSSM_EN;
>> +			appl_writel(pcie, data, APPL_CTRL);
>> +		}
>> +	}
>> +	/*
>> +	 * DBI registers may not be accessible after this as PLL-E would be
>> +	 * down depending on how CLKREQ is pulled by end point
>> +	 */
>> +	data = appl_readl(pcie, APPL_PINMUX);
>> +	data |= (APPL_PINMUX_CLKREQ_OVERRIDE_EN | APPL_PINMUX_CLKREQ_OVERRIDE);
>> +	/* Cut REFCLK to slot */
>> +	data |= APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE_EN;
>> +	data &= ~APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE;
>> +	appl_writel(pcie, data, APPL_PINMUX);
>> +}
>> +
>> +static int tegra_pcie_deinit_controller(struct tegra_pcie_dw *pcie)
>> +{
>> +	/*
>> +	 * link doesn't go into L2 state with some of the endpoints with Tegra
>> +	 * if they are not in D0 state. So, need to make sure that immediate
>> +	 * downstream devices are in D0 state before sending PME_TurnOff to put
>> +	 * link into L2 state
>> +	 */
>> +	tegra_pcie_downstream_dev_to_D0(pcie);
>> +	dw_pcie_host_deinit(&pcie->pci.pp);
>> +	tegra_pcie_dw_pme_turnoff(pcie);
>> +	return __deinit_controller(pcie);
>> +}
>> +
>> +static int tegra_pcie_config_rp(struct tegra_pcie_dw *pcie)
>> +{
>> +	struct pcie_port *pp = &pcie->pci.pp;
>> +	struct device *dev = pcie->dev;
>> +	char *name;
>> +	int ret;
>> +
>> +	if (IS_ENABLED(CONFIG_PCI_MSI)) {
>> +		pp->msi_irq = of_irq_get_byname(dev->of_node, "msi");
>> +		if (!pp->msi_irq) {
>> +			dev_err(dev, "Failed to get MSI interrupt\n");
>> +			return -ENODEV;
>> +		}
>> +	}
>> +
>> +	pm_runtime_enable(dev);
>> +	ret = pm_runtime_get_sync(dev);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to get runtime sync for PCIe dev: %d\n",
>> +			ret);
>> +		pm_runtime_disable(dev);
>> +		return ret;
>> +	}
>> +
>> +	tegra_pcie_init_controller(pcie);
>> +
>> +	pcie->link_state = tegra_pcie_dw_link_up(&pcie->pci);
>> +
>> +	if (!pcie->link_state) {
>> +		ret = -ENOMEDIUM;
>> +		goto fail_host_init;
>> +	}
>> +
>> +	name = devm_kasprintf(dev, GFP_KERNEL, "%pOFP", dev->of_node);
>> +	if (!name) {
>> +		ret = -ENOMEM;
>> +		goto fail_host_init;
>> +	}
>> +
>> +	pcie->debugfs = debugfs_create_dir(name, NULL);
>> +	if (!pcie->debugfs)
>> +		dev_err(dev, "Failed to create debugfs\n");
>> +	else
>> +		init_debugfs(pcie);
>> +
>> +	return ret;
>> +
>> +fail_host_init:
>> +	tegra_pcie_deinit_controller(pcie);
>> +	pm_runtime_put_sync(dev);
>> +	pm_runtime_disable(dev);
>> +	return ret;
>> +}
>> +
>> +static const struct tegra_pcie_soc tegra_pcie_rc_of_data = {
>> +	.mode = DW_PCIE_RC_TYPE,
>> +};
>> +
>> +static const struct of_device_id tegra_pcie_dw_of_match[] = {
>> +	{
>> +		.compatible = "nvidia,tegra194-pcie",
>> +		.data = &tegra_pcie_rc_of_data,
>> +	},
>> +	{},
>> +};
>> +MODULE_DEVICE_TABLE(of, tegra_pcie_dw_of_match);
> 
> Move it closer to end of file where MODULE_DESCRIPTION() et al are.
Ok.

> 
>> +
>> +static int tegra_pcie_dw_probe(struct platform_device *pdev)
>> +{
>> +	const struct tegra_pcie_soc *data;
>> +	struct device *dev = &pdev->dev;
>> +	struct resource *atu_dma_res;
>> +	struct tegra_pcie_dw *pcie;
>> +	struct resource *dbi_res;
>> +	struct pcie_port *pp;
>> +	struct dw_pcie *pci;
>> +	struct phy **phys;
>> +	char *name;
>> +	int ret;
>> +	u32 i;
>> +
>> +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
>> +	if (!pcie)
>> +		return -ENOMEM;
>> +
>> +	pci = &pcie->pci;
>> +	pci->dev = &pdev->dev;
>> +	pci->ops = &tegra_dw_pcie_ops;
>> +	pp = &pci->pp;
>> +	pcie->dev = &pdev->dev;
>> +
>> +	data = (struct tegra_pcie_soc *)of_device_get_match_data(dev);
>> +	if (!data)
>> +		return -EINVAL;
>> +	pcie->mode = (enum dw_pcie_device_mode)data->mode;
>> +
>> +	ret = tegra_pcie_dw_parse_dt(pcie);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to parse device tree: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	pcie->pex_ctl_supply = devm_regulator_get(dev, "vddio-pex-ctl");
>> +	if (IS_ERR(pcie->pex_ctl_supply)) {
>> +		dev_err(dev, "Failed to get regulator: %ld\n",
>> +			PTR_ERR(pcie->pex_ctl_supply));
>> +		return PTR_ERR(pcie->pex_ctl_supply);
>> +	}
>> +
>> +	pcie->core_clk = devm_clk_get(dev, "core");
>> +	if (IS_ERR(pcie->core_clk)) {
>> +		dev_err(dev, "Failed to get core clock: %ld\n",
>> +			PTR_ERR(pcie->core_clk));
>> +		return PTR_ERR(pcie->core_clk);
>> +	}
>> +
>> +	pcie->appl_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>> +						      "appl");
>> +	if (!pcie->appl_res) {
>> +		dev_err(dev, "Failed to find \"appl\" region\n");
>> +		return PTR_ERR(pcie->appl_res);
>> +	}
> 
> Add an empty line.
Ok.

> 
>> +	pcie->appl_base = devm_ioremap_resource(dev, pcie->appl_res);
>> +	if (IS_ERR(pcie->appl_base))
>> +		return PTR_ERR(pcie->appl_base);
>> +
>> +	pcie->core_apb_rst = devm_reset_control_get(dev, "apb");
>> +	if (IS_ERR(pcie->core_apb_rst)) {
>> +		dev_err(dev, "Failed to get APB reset: %ld\n",
>> +			PTR_ERR(pcie->core_apb_rst));
>> +		return PTR_ERR(pcie->core_apb_rst);
>> +	}
>> +
>> +	phys = devm_kcalloc(dev, pcie->phy_count, sizeof(*phys), GFP_KERNEL);
>> +	if (!phys)
>> +		return PTR_ERR(phys);
>> +
>> +	for (i = 0; i < pcie->phy_count; i++) {
>> +		name = kasprintf(GFP_KERNEL, "p2u-%u", i);
>> +		if (!name) {
>> +			dev_err(dev, "Failed to create P2U string\n");
>> +			return -ENOMEM;
>> +		}
>> +		phys[i] = devm_phy_get(dev, name);
>> +		kfree(name);
>> +		if (IS_ERR(phys[i])) {
>> +			ret = PTR_ERR(phys[i]);
>> +			dev_err(dev, "Failed to get PHY: %d\n", ret);
>> +			return ret;
>> +		}
>> +	}
>> +
>> +	pcie->phys = phys;
>> +
>> +	dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
>> +	if (!dbi_res) {
>> +		dev_err(dev, "Failed to find \"dbi\" region\n");
>> +		return PTR_ERR(dbi_res);
>> +	}
>> +	pcie->dbi_res = dbi_res;
>> +
>> +	pci->dbi_base = devm_ioremap_resource(dev, dbi_res);
>> +	if (IS_ERR(pci->dbi_base))
>> +		return PTR_ERR(pci->dbi_base);
>> +
>> +	/* Tegra HW locates DBI2 at a fixed offset from DBI */
>> +	pci->dbi_base2 = pci->dbi_base + 0x1000;
>> +
>> +	atu_dma_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>> +						   "atu_dma");
>> +	if (!atu_dma_res) {
>> +		dev_err(dev, "Failed to find \"atu_dma\" region\n");
>> +		return PTR_ERR(atu_dma_res);
>> +	}
>> +	pcie->atu_dma_res = atu_dma_res;
> 
> Add an empty line.
> 
> I have just skimmed over it, I need more time to review the driver more
> thoroughly, I will try to go over it tomorrow and we can see if we can
> hit v5.3 but I can't guarantee anything, sorry but there was a
> significant backlog on the PCI patch queue.
> 
> The rest of the series is fine but it is useless to merge it
> without this patch so let's see how it goes.
Ok. I'll wait for your thorough review and then push next patch.
Thanks for the review.

> 
> Lorenzo
> 
>> +	pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);
>> +	if (IS_ERR(pci->atu_base))
>> +		return PTR_ERR(pci->atu_base);
>> +
>> +	pcie->core_rst = devm_reset_control_get(dev, "core");
>> +	if (IS_ERR(pcie->core_rst)) {
>> +		dev_err(dev, "Failed to get core reset: %ld\n",
>> +			PTR_ERR(pcie->core_rst));
>> +		return PTR_ERR(pcie->core_rst);
>> +	}
>> +
>> +	pp->irq = platform_get_irq_byname(pdev, "intr");
>> +	if (!pp->irq) {
>> +		dev_err(dev, "Failed to get \"intr\" interrupt\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	ret = devm_request_irq(dev, pp->irq, tegra_pcie_irq_handler,
>> +			       IRQF_SHARED, "tegra-pcie-intr", pcie);
>> +	if (ret) {
>> +		dev_err(dev, "Failed to request IRQ %d: %d\n", pp->irq, ret);
>> +		return ret;
>> +	}
>> +
>> +	pcie->bpmp = tegra_bpmp_get(dev);
>> +	if (IS_ERR(pcie->bpmp))
>> +		return PTR_ERR(pcie->bpmp);
>> +
>> +	platform_set_drvdata(pdev, pcie);
>> +
>> +	if (pcie->mode == DW_PCIE_RC_TYPE) {
>> +		ret = tegra_pcie_config_rp(pcie);
>> +		if (ret && ret != -ENOMEDIUM)
>> +			goto fail;
>> +		else
>> +			return 0;
>> +	}
>> +
>> +fail:
>> +	tegra_bpmp_put(pcie->bpmp);
>> +	return ret;
>> +}
>> +
>> +static int tegra_pcie_dw_remove(struct platform_device *pdev)
>> +{
>> +	struct tegra_pcie_dw *pcie = platform_get_drvdata(pdev);
>> +
>> +	if (pcie->mode != DW_PCIE_RC_TYPE)
>> +		return 0;
>> +
>> +	if (!pcie->link_state)
>> +		return 0;
>> +
>> +	debugfs_remove_recursive(pcie->debugfs);
>> +	tegra_pcie_deinit_controller(pcie);
>> +	pm_runtime_put_sync(pcie->dev);
>> +	pm_runtime_disable(pcie->dev);
>> +	tegra_bpmp_put(pcie->bpmp);
>> +
>> +	return 0;
>> +}
>> +
>> +static int tegra_pcie_dw_suspend_late(struct device *dev)
>> +{
>> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
>> +	u32 val;
>> +
>> +	if (!pcie->link_state)
>> +		return 0;
>> +
>> +	/* Enable HW_HOT_RST mode */
>> +	val = appl_readl(pcie, APPL_CTRL);
>> +	val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
>> +		 APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
>> +	val |= APPL_CTRL_HW_HOT_RST_EN;
>> +	appl_writel(pcie, val, APPL_CTRL);
>> +
>> +	return 0;
>> +}
>> +
>> +static int tegra_pcie_dw_suspend_noirq(struct device *dev)
>> +{
>> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
>> +
>> +	if (!pcie->link_state)
>> +		return 0;
>> +
>> +	/* Save MSI interrupt vector */
>> +	pcie->msi_ctrl_int = dw_pcie_readl_dbi(&pcie->pci,
>> +					       PORT_LOGIC_MSI_CTRL_INT_0_EN);
>> +	tegra_pcie_downstream_dev_to_D0(pcie);
>> +	tegra_pcie_dw_pme_turnoff(pcie);
>> +	return __deinit_controller(pcie);
>> +}
>> +
>> +static int tegra_pcie_dw_resume_noirq(struct device *dev)
>> +{
>> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
>> +	int ret;
>> +
>> +	if (!pcie->link_state)
>> +		return 0;
>> +
>> +	ret = tegra_pcie_config_controller(pcie, true);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	ret = tegra_pcie_dw_host_init(&pcie->pci.pp);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to init host: %d\n", ret);
>> +		goto fail_host_init;
>> +	}
>> +
>> +	/* Restore MSI interrupt vector */
>> +	dw_pcie_writel_dbi(&pcie->pci, PORT_LOGIC_MSI_CTRL_INT_0_EN,
>> +			   pcie->msi_ctrl_int);
>> +
>> +	return 0;
>> +fail_host_init:
>> +	return __deinit_controller(pcie);
>> +}
>> +
>> +static int tegra_pcie_dw_resume_early(struct device *dev)
>> +{
>> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
>> +	u32 val;
>> +
>> +	if (!pcie->link_state)
>> +		return 0;
>> +
>> +	/* Disable HW_HOT_RST mode */
>> +	val = appl_readl(pcie, APPL_CTRL);
>> +	val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
>> +		 APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
>> +	val |= APPL_CTRL_HW_HOT_RST_MODE_IMDT_RST <<
>> +	       APPL_CTRL_HW_HOT_RST_MODE_SHIFT;
>> +	val &= ~APPL_CTRL_HW_HOT_RST_EN;
>> +	appl_writel(pcie, val, APPL_CTRL);
>> +
>> +	return 0;
>> +}
>> +
>> +static void tegra_pcie_dw_shutdown(struct platform_device *pdev)
>> +{
>> +	struct tegra_pcie_dw *pcie = platform_get_drvdata(pdev);
>> +
>> +	if (pcie->mode != DW_PCIE_RC_TYPE)
>> +		return;
>> +
>> +	if (!pcie->link_state)
>> +		return;
>> +
>> +	debugfs_remove_recursive(pcie->debugfs);
>> +	tegra_pcie_downstream_dev_to_D0(pcie);
>> +
>> +	disable_irq(pcie->pci.pp.irq);
>> +	if (IS_ENABLED(CONFIG_PCI_MSI))
>> +		disable_irq(pcie->pci.pp.msi_irq);
>> +
>> +	tegra_pcie_dw_pme_turnoff(pcie);
>> +	__deinit_controller(pcie);
>> +}
>> +
>> +static const struct dev_pm_ops tegra_pcie_dw_pm_ops = {
>> +	.suspend_late = tegra_pcie_dw_suspend_late,
>> +	.suspend_noirq = tegra_pcie_dw_suspend_noirq,
>> +	.resume_noirq = tegra_pcie_dw_resume_noirq,
>> +	.resume_early = tegra_pcie_dw_resume_early,
>> +};
>> +
>> +static struct platform_driver tegra_pcie_dw_driver = {
>> +	.probe = tegra_pcie_dw_probe,
>> +	.remove = tegra_pcie_dw_remove,
>> +	.shutdown = tegra_pcie_dw_shutdown,
>> +	.driver = {
>> +		.name	= "tegra194-pcie",
>> +		.pm = &tegra_pcie_dw_pm_ops,
>> +		.of_match_table = tegra_pcie_dw_of_match,
>> +	},
>> +};
>> +module_platform_driver(tegra_pcie_dw_driver);
>> +
>> +MODULE_AUTHOR("Vidya Sagar <vidyas@nvidia.com>");
>> +MODULE_DESCRIPTION("NVIDIA PCIe host controller driver");
>> +MODULE_LICENSE("GPL v2");
>> -- 
>> 2.17.1
>>

On Wed, Jul 10, 2019 at 11:52:12AM +0530, Vidya Sagar wrote:

[...]

> diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
> new file mode 100644
> index 000000000000..189779edd976
> --- /dev/null
> +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
> @@ -0,0 +1,1632 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * PCIe host controller driver for Tegra194 SoC
> + *
> + * Copyright (C) 2019 NVIDIA Corporation.
> + *
> + * Author: Vidya Sagar <vidyas@nvidia.com>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/debugfs.h>
> +#include <linux/delay.h>
> +#include <linux/gpio.h>
> +#include <linux/interrupt.h>
> +#include <linux/iopoll.h>
> +#include <linux/kernel.h>
> +#include <linux/kfifo.h>
> +#include <linux/kthread.h>

What do you need these two headers for ?

[...]

> +struct tegra_pcie_dw {
> +	struct device *dev;
> +	struct resource *appl_res;
> +	struct resource *dbi_res;
> +	struct resource *atu_dma_res;
> +	void __iomem *appl_base;
> +	struct clk *core_clk;
> +	struct reset_control *core_apb_rst;
> +	struct reset_control *core_rst;
> +	struct dw_pcie pci;
> +	enum dw_pcie_device_mode mode;
> +	struct tegra_bpmp *bpmp;
> +
> +	bool supports_clkreq;
> +	bool enable_cdm_check;
> +	u8 init_link_width;
> +	bool link_state;
> +	u32 msi_ctrl_int;
> +	u32 num_lanes;
> +	u32 max_speed;
> +	u32 cid;
> +	bool update_fc_fixup;
> +	u32 cfg_link_cap_l1sub;
> +	u32 pcie_cap_base;
> +	u32 aspm_cmrt;
> +	u32 aspm_pwr_on_t;
> +	u32 aspm_l0s_enter_lat;o

Nit: You should try to group variables according to their usage,
it would make sense to group booleans together.

> +	struct regulator *pex_ctl_supply;
> +
> +	unsigned int phy_count;
> +	struct phy **phys;
> +
> +	struct dentry *debugfs;
> +};
> +
> +static inline struct tegra_pcie_dw *to_tegra_pcie(struct dw_pcie *pci)
> +{
> +	return container_of(pci, struct tegra_pcie_dw, pci);
> +}
> +
> +static inline void appl_writel(struct tegra_pcie_dw *pcie, const u32 value,
> +			       const u32 reg)
> +{
> +	writel_relaxed(value, pcie->appl_base + reg);
> +}
> +
> +static inline u32 appl_readl(struct tegra_pcie_dw *pcie, const u32 reg)
> +{
> +	return readl_relaxed(pcie->appl_base + reg);
> +}
> +
> +struct tegra_pcie_soc {
> +	enum dw_pcie_device_mode mode;
> +};
> +
> +static void apply_bad_link_workaround(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> +	u32 current_link_width;
> +	u16 val;
> +
> +	/*
> +	 * NOTE:- Since this scenario is uncommon and link as such is not
> +	 * stable anyway, not waiting to confirm if link is really
> +	 * transitioning to Gen-2 speed
> +	 */
> +	val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
> +	if (val & PCI_EXP_LNKSTA_LBMS) {
> +		current_link_width = (val & PCI_EXP_LNKSTA_NLW) >>
> +				     PCI_EXP_LNKSTA_NLW_SHIFT;
> +		if (pcie->init_link_width > current_link_width) {
> +			dev_warn(pci->dev, "PCIe link is bad, width reduced\n");
> +			val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
> +						PCI_EXP_LNKCTL2);
> +			val &= ~PCI_EXP_LNKCTL2_TLS;
> +			val |= PCI_EXP_LNKCTL2_TLS_2_5GT;
> +			dw_pcie_writew_dbi(pci, pcie->pcie_cap_base +
> +					   PCI_EXP_LNKCTL2, val);
> +
> +			val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
> +						PCI_EXP_LNKCTL);
> +			val |= PCI_EXP_LNKCTL_RL;
> +			dw_pcie_writew_dbi(pci, pcie->pcie_cap_base +
> +					   PCI_EXP_LNKCTL, val);
> +		}
> +	}
> +}
> +
> +static irqreturn_t tegra_pcie_rp_irq_handler(struct tegra_pcie_dw *pcie)
> +{
> +	struct dw_pcie *pci = &pcie->pci;
> +	struct pcie_port *pp = &pci->pp;
> +	u32 val, tmp;
> +	u16 val_w;
> +
> +	val = appl_readl(pcie, APPL_INTR_STATUS_L0);
> +	if (val & APPL_INTR_STATUS_L0_LINK_STATE_INT) {
> +		val = appl_readl(pcie, APPL_INTR_STATUS_L1_0_0);
> +		if (val & APPL_INTR_STATUS_L1_0_0_LINK_REQ_RST_NOT_CHGED) {
> +			appl_writel(pcie, val, APPL_INTR_STATUS_L1_0_0);
> +
> +			/* SBR & Surprise Link Down WAR */
> +			val = appl_readl(pcie, APPL_CAR_RESET_OVRD);
> +			val &= ~APPL_CAR_RESET_OVRD_CYA_OVERRIDE_CORE_RST_N;
> +			appl_writel(pcie, val, APPL_CAR_RESET_OVRD);
> +			udelay(1);
> +			val = appl_readl(pcie, APPL_CAR_RESET_OVRD);
> +			val |= APPL_CAR_RESET_OVRD_CYA_OVERRIDE_CORE_RST_N;
> +			appl_writel(pcie, val, APPL_CAR_RESET_OVRD);
> +
> +			val = dw_pcie_readl_dbi(pci, PORT_LOGIC_GEN2_CTRL);
> +			val |= PORT_LOGIC_GEN2_CTRL_DIRECT_SPEED_CHANGE;
> +			dw_pcie_writel_dbi(pci, PORT_LOGIC_GEN2_CTRL, val);
> +		}
> +	}
> +
> +	if (val & APPL_INTR_STATUS_L0_INT_INT) {
> +		val = appl_readl(pcie, APPL_INTR_STATUS_L1_8_0);
> +		if (val & APPL_INTR_STATUS_L1_8_0_AUTO_BW_INT_STS) {
> +			appl_writel(pcie,
> +				    APPL_INTR_STATUS_L1_8_0_AUTO_BW_INT_STS,
> +				    APPL_INTR_STATUS_L1_8_0);
> +			apply_bad_link_workaround(pp);
> +		}
> +		if (val & APPL_INTR_STATUS_L1_8_0_BW_MGT_INT_STS) {
> +			appl_writel(pcie,
> +				    APPL_INTR_STATUS_L1_8_0_BW_MGT_INT_STS,
> +				    APPL_INTR_STATUS_L1_8_0);
> +
> +			val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
> +						  PCI_EXP_LNKSTA);
> +			dev_dbg(pci->dev, "Link Speed : Gen-%u\n", val_w &
> +				PCI_EXP_LNKSTA_CLS);
> +		}
> +	}
> +
> +	val = appl_readl(pcie, APPL_INTR_STATUS_L0);
> +	if (val & APPL_INTR_STATUS_L0_CDM_REG_CHK_INT) {
> +		val = appl_readl(pcie, APPL_INTR_STATUS_L1_18);
> +		tmp = dw_pcie_readl_dbi(pci, PCIE_PL_CHK_REG_CONTROL_STATUS);
> +		if (val & APPL_INTR_STATUS_L1_18_CDM_REG_CHK_CMPLT) {
> +			dev_info(pci->dev, "CDM check complete\n");
> +			tmp |= PCIE_PL_CHK_REG_CHK_REG_COMPLETE;
> +		}
> +		if (val & APPL_INTR_STATUS_L1_18_CDM_REG_CHK_CMP_ERR) {
> +			dev_err(pci->dev, "CDM comparison mismatch\n");
> +			tmp |= PCIE_PL_CHK_REG_CHK_REG_COMPARISON_ERROR;
> +		}
> +		if (val & APPL_INTR_STATUS_L1_18_CDM_REG_CHK_LOGIC_ERR) {
> +			dev_err(pci->dev, "CDM Logic error\n");
> +			tmp |= PCIE_PL_CHK_REG_CHK_REG_LOGIC_ERROR;
> +		}
> +		dw_pcie_writel_dbi(pci, PCIE_PL_CHK_REG_CONTROL_STATUS, tmp);
> +		tmp = dw_pcie_readl_dbi(pci, PCIE_PL_CHK_REG_ERR_ADDR);
> +		dev_err(pci->dev, "CDM Error Address Offset = 0x%08X\n", tmp);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t tegra_pcie_irq_handler(int irq, void *arg)
> +{
> +	struct tegra_pcie_dw *pcie = arg;
> +
> +	if (pcie->mode == DW_PCIE_RC_TYPE)
> +		return tegra_pcie_rp_irq_handler(pcie);

What's the point of registering the handler if mode != DW_PCIE_RC_TYPE ?

> +	return IRQ_NONE;
> +}
> +
> +static int tegra_pcie_dw_rd_own_conf(struct pcie_port *pp, int where, int size,
> +				     u32 *val)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +
> +	/*
> +	 * This is an endpoint mode specific register happen to appear even
> +	 * when controller is operating in root port mode and system hangs
> +	 * when it is accessed with link being in ASPM-L1 state.
> +	 * So skip accessing it altogether
> +	 */
> +	if (where == PORT_LOGIC_MSIX_DOORBELL) {
> +		*val = 0x00000000;
> +		return PCIBIOS_SUCCESSFUL;
> +	}
> +
> +	return dw_pcie_read(pci->dbi_base + where, size, val);
> +}
> +
> +static int tegra_pcie_dw_wr_own_conf(struct pcie_port *pp, int where, int size,
> +				     u32 val)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +
> +	/*
> +	 * This is an endpoint mode specific register happen to appear even
> +	 * when controller is operating in root port mode and system hangs
> +	 * when it is accessed with link being in ASPM-L1 state.
> +	 * So skip accessing it altogether
> +	 */
> +	if (where == PORT_LOGIC_MSIX_DOORBELL)
> +		return PCIBIOS_SUCCESSFUL;
> +
> +	return dw_pcie_write(pci->dbi_base + where, size, val);
> +}
> +
> +#if defined(CONFIG_PCIEASPM)
> +static void disable_aspm_l11(struct tegra_pcie_dw *pcie)
> +{
> +	u32 val;
> +
> +	val = dw_pcie_readl_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub);
> +	val &= ~PCI_L1SS_CAP_ASPM_L1_1;
> +	dw_pcie_writel_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub, val);
> +}
> +
> +static void disable_aspm_l12(struct tegra_pcie_dw *pcie)
> +{
> +	u32 val;
> +
> +	val = dw_pcie_readl_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub);
> +	val &= ~PCI_L1SS_CAP_ASPM_L1_2;
> +	dw_pcie_writel_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub, val);
> +}
> +
> +static inline u32 event_counter_prog(struct tegra_pcie_dw *pcie, u32 event)
> +{
> +	u32 val;
> +
> +	val = dw_pcie_readl_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid]);
> +	val &= ~(EVENT_COUNTER_EVENT_SEL_MASK << EVENT_COUNTER_EVENT_SEL_SHIFT);
> +	val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
> +	val |= event << EVENT_COUNTER_EVENT_SEL_SHIFT;
> +	val |= EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
> +	dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid], val);
> +	val = dw_pcie_readl_dbi(&pcie->pci, event_cntr_data_offset[pcie->cid]);
> +	return val;
> +}
> +
> +static int aspm_state_cnt(struct seq_file *s, void *data)
> +{
> +	struct tegra_pcie_dw *pcie = (struct tegra_pcie_dw *)
> +				     dev_get_drvdata(s->private);
> +	u32 val;
> +
> +	seq_printf(s, "Tx L0s entry count : %u\n",
> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_Tx_L0S));
> +
> +	seq_printf(s, "Rx L0s entry count : %u\n",
> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_Rx_L0S));
> +
> +	seq_printf(s, "Link L1 entry count : %u\n",
> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1));
> +
> +	seq_printf(s, "Link L1.1 entry count : %u\n",
> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1_1));
> +
> +	seq_printf(s, "Link L1.2 entry count : %u\n",
> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1_2));
> +
> +	/* Clear all counters */
> +	dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid],
> +			   EVENT_COUNTER_ALL_CLEAR);
> +
> +	/* Re-enable counting */
> +	val = EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
> +	val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
> +	dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid], val);
> +
> +	return 0;
> +}
> +#endif
> +
> +static int init_debugfs(struct tegra_pcie_dw *pcie)
> +{
> +#if defined(CONFIG_PCIEASPM)
> +	struct dentry *d;
> +
> +	d = debugfs_create_devm_seqfile(pcie->dev, "aspm_state_cnt",
> +					pcie->debugfs, aspm_state_cnt);
> +	if (IS_ERR_OR_NULL(d))
> +		dev_err(pcie->dev,
> +			"Failed to create debugfs file \"aspm_state_cnt\"\n");
> +#endif
> +	return 0;
> +}
> +
> +static void tegra_pcie_enable_system_interrupts(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> +	u32 val;
> +	u16 val_w;
> +
> +	val = appl_readl(pcie, APPL_INTR_EN_L0_0);
> +	val |= APPL_INTR_EN_L0_0_LINK_STATE_INT_EN;
> +	appl_writel(pcie, val, APPL_INTR_EN_L0_0);
> +
> +	val = appl_readl(pcie, APPL_INTR_EN_L1_0_0);
> +	val |= APPL_INTR_EN_L1_0_0_LINK_REQ_RST_NOT_INT_EN;
> +	appl_writel(pcie, val, APPL_INTR_EN_L1_0_0);
> +
> +	if (pcie->enable_cdm_check) {
> +		val = appl_readl(pcie, APPL_INTR_EN_L0_0);
> +		val |= APPL_INTR_EN_L0_0_CDM_REG_CHK_INT_EN;
> +		appl_writel(pcie, val, APPL_INTR_EN_L0_0);
> +
> +		val = appl_readl(pcie, APPL_INTR_EN_L1_18);
> +		val |= APPL_INTR_EN_L1_18_CDM_REG_CHK_CMP_ERR;
> +		val |= APPL_INTR_EN_L1_18_CDM_REG_CHK_LOGIC_ERR;
> +		appl_writel(pcie, val, APPL_INTR_EN_L1_18);
> +	}
> +
> +	val_w = dw_pcie_readw_dbi(&pcie->pci, pcie->pcie_cap_base +
> +				  PCI_EXP_LNKSTA);
> +	pcie->init_link_width = (val_w & PCI_EXP_LNKSTA_NLW) >>
> +				PCI_EXP_LNKSTA_NLW_SHIFT;
> +
> +	val_w = dw_pcie_readw_dbi(&pcie->pci, pcie->pcie_cap_base +
> +				  PCI_EXP_LNKCTL);
> +	val_w |= PCI_EXP_LNKCTL_LBMIE;
> +	dw_pcie_writew_dbi(&pcie->pci, pcie->pcie_cap_base + PCI_EXP_LNKCTL,
> +			   val_w);
> +}
> +
> +static void tegra_pcie_enable_legacy_interrupts(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> +	u32 val;
> +
> +	/* Enable legacy interrupt generation */
> +	val = appl_readl(pcie, APPL_INTR_EN_L0_0);
> +	val |= APPL_INTR_EN_L0_0_SYS_INTR_EN;
> +	val |= APPL_INTR_EN_L0_0_INT_INT_EN;
> +	appl_writel(pcie, val, APPL_INTR_EN_L0_0);
> +
> +	val = appl_readl(pcie, APPL_INTR_EN_L1_8_0);
> +	val |= APPL_INTR_EN_L1_8_INTX_EN;
> +	val |= APPL_INTR_EN_L1_8_AUTO_BW_INT_EN;
> +	val |= APPL_INTR_EN_L1_8_BW_MGT_INT_EN;
> +	if (IS_ENABLED(CONFIG_PCIEAER))
> +		val |= APPL_INTR_EN_L1_8_AER_INT_EN;
> +	appl_writel(pcie, val, APPL_INTR_EN_L1_8_0);
> +}
> +
> +static void tegra_pcie_enable_msi_interrupts(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> +	u32 val;
> +
> +	dw_pcie_msi_init(pp);
> +
> +	/* Enable MSI interrupt generation */
> +	val = appl_readl(pcie, APPL_INTR_EN_L0_0);
> +	val |= APPL_INTR_EN_L0_0_SYS_MSI_INTR_EN;
> +	val |= APPL_INTR_EN_L0_0_MSI_RCV_INT_EN;
> +	appl_writel(pcie, val, APPL_INTR_EN_L0_0);
> +}
> +
> +static void tegra_pcie_enable_interrupts(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> +
> +	/* Clear interrupt statuses before enabling interrupts */
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L0);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_0_0);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_1);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_2);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_3);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_6);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_7);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_8_0);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_9);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_10);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_11);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_13);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_14);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_15);
> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_17);
> +
> +	tegra_pcie_enable_system_interrupts(pp);
> +	tegra_pcie_enable_legacy_interrupts(pp);
> +	if (IS_ENABLED(CONFIG_PCI_MSI))
> +		tegra_pcie_enable_msi_interrupts(pp);
> +}
> +
> +static void config_gen3_gen4_eq_presets(struct tegra_pcie_dw *pcie)
> +{
> +	struct dw_pcie *pci = &pcie->pci;
> +	u32 val, offset, i;
> +
> +	/* Program init preset */
> +	for (i = 0; i < pcie->num_lanes; i++) {
> +		dw_pcie_read(pci->dbi_base + CAP_SPCIE_CAP_OFF
> +				 + (i * 2), 2, &val);
> +		val &= ~CAP_SPCIE_CAP_OFF_DSP_TX_PRESET0_MASK;
> +		val |= GEN3_GEN4_EQ_PRESET_INIT;
> +		val &= ~CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_MASK;
> +		val |= (GEN3_GEN4_EQ_PRESET_INIT <<
> +			   CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_SHIFT);
> +		dw_pcie_write(pci->dbi_base + CAP_SPCIE_CAP_OFF
> +				 + (i * 2), 2, val);
> +
> +		offset = dw_pcie_find_ext_capability(pci,
> +						     PCI_EXT_CAP_ID_PL_16GT) +
> +				PCI_PL_16GT_LE_CTRL;
> +		dw_pcie_read(pci->dbi_base + offset + i, 1, &val);
> +		val &= ~PCI_PL_16GT_LE_CTRL_DSP_TX_PRESET_MASK;
> +		val |= GEN3_GEN4_EQ_PRESET_INIT;
> +		val &= ~PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_MASK;
> +		val |= (GEN3_GEN4_EQ_PRESET_INIT <<
> +			PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_SHIFT);
> +		dw_pcie_write(pci->dbi_base + offset + i, 1, val);
> +	}
> +
> +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
> +	val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
> +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
> +
> +	val = dw_pcie_readl_dbi(pci, GEN3_EQ_CONTROL_OFF);
> +	val &= ~GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK;
> +	val |= (0x3ff << GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_SHIFT);
> +	val &= ~GEN3_EQ_CONTROL_OFF_FB_MODE_MASK;
> +	dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, val);
> +
> +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
> +	val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
> +	val |= (0x1 << GEN3_RELATED_OFF_RATE_SHADOW_SEL_SHIFT);
> +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
> +
> +	val = dw_pcie_readl_dbi(pci, GEN3_EQ_CONTROL_OFF);
> +	val &= ~GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK;
> +	val |= (0x360 << GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_SHIFT);
> +	val &= ~GEN3_EQ_CONTROL_OFF_FB_MODE_MASK;
> +	dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, val);
> +
> +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
> +	val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
> +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
> +}
> +
> +static int tegra_pcie_dw_host_init(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> +	u32 val, tmp, offset, speed;
> +	unsigned int count;
> +	u16 val_w;
> +
> +core_init:

I think it would be cleaner to include all registers programming
within a function and we remove this label (and goto) below.

> +	count = 200;

It would be easier to read if we could inizialize this value closer
to where it is actually used. Actually explaining why 200 as value
was chosen would be appreciated.

> +#if defined(CONFIG_PCIEASPM)
> +	offset = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_L1SS);
> +	pcie->cfg_link_cap_l1sub = offset + PCI_L1SS_CAP;
> +#endif

Please try to factor this out within a single #ifdef guard.

> +	val = dw_pcie_readl_dbi(pci, PCI_IO_BASE);
> +	val &= ~(IO_BASE_IO_DECODE | IO_BASE_IO_DECODE_BIT8);
> +	dw_pcie_writel_dbi(pci, PCI_IO_BASE, val);
> +
> +	val = dw_pcie_readl_dbi(pci, PCI_PREF_MEMORY_BASE);
> +	val |= CFG_PREF_MEM_LIMIT_BASE_MEM_DECODE;
> +	val |= CFG_PREF_MEM_LIMIT_BASE_MEM_LIMIT_DECODE;
> +	dw_pcie_writel_dbi(pci, PCI_PREF_MEMORY_BASE, val);
> +
> +	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 0);
> +
> +	/* Configure FTS */
> +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL);
> +	val &= ~(N_FTS_MASK << N_FTS_SHIFT);
> +	val |= N_FTS_VAL << N_FTS_SHIFT;
> +	dw_pcie_writel_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL, val);
> +
> +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_GEN2_CTRL);
> +	val &= ~FTS_MASK;
> +	val |= FTS_VAL;
> +	dw_pcie_writel_dbi(pci, PORT_LOGIC_GEN2_CTRL, val);
> +
> +	/* Enable as 0xFFFF0001 response for CRS */
> +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT);
> +	val &= ~(AMBA_ERROR_RESPONSE_CRS_MASK << AMBA_ERROR_RESPONSE_CRS_SHIFT);
> +	val |= (AMBA_ERROR_RESPONSE_CRS_OKAY_FFFF0001 <<
> +		AMBA_ERROR_RESPONSE_CRS_SHIFT);
> +	dw_pcie_writel_dbi(pci, PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT, val);
> +
> +	/* Configure Max Speed from DT */
> +	if (pcie->max_speed && pcie->max_speed != -EINVAL) {
> +		val = dw_pcie_readl_dbi(pci, pcie->pcie_cap_base +
> +					PCI_EXP_LNKCAP);
> +		val &= ~PCI_EXP_LNKCAP_SLS;
> +		val |= pcie->max_speed;
> +		dw_pcie_writel_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP,
> +				   val);
> +	}
> +
> +	/* Configure Max lane width from DT */
> +	val = dw_pcie_readl_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP);
> +	val &= ~PCI_EXP_LNKCAP_MLW;
> +	val |= (pcie->num_lanes << PCI_EXP_LNKSTA_NLW_SHIFT);
> +	dw_pcie_writel_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP, val);
> +
> +	config_gen3_gen4_eq_presets(pcie);
> +
> +#if defined(CONFIG_PCIEASPM)
> +	/* Enable ASPM counters */
> +	val = EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
> +	val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
> +	dw_pcie_writel_dbi(pci, event_cntr_ctrl_offset[pcie->cid], val);
> +
> +	/* Program T_cmrt and T_pwr_on values */
> +	val = dw_pcie_readl_dbi(pci, pcie->cfg_link_cap_l1sub);
> +	val &= ~(PCI_L1SS_CAP_CM_RESTORE_TIME | PCI_L1SS_CAP_P_PWR_ON_VALUE);
> +	val |= (pcie->aspm_cmrt << 8);
> +	val |= (pcie->aspm_pwr_on_t << 19);
> +	dw_pcie_writel_dbi(pci, pcie->cfg_link_cap_l1sub, val);
> +
> +	/* Program L0s and L1 entrance latencies */
> +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL);
> +	val &= ~L0S_ENTRANCE_LAT_MASK;
> +	val |= (pcie->aspm_l0s_enter_lat << L0S_ENTRANCE_LAT_SHIFT);
> +	val |= ENTER_ASPM;
> +	dw_pcie_writel_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL, val);
> +#endif

See above.

> +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
> +	val &= ~GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL;
> +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
> +
> +	if (pcie->update_fc_fixup) {
> +		val = dw_pcie_readl_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF);
> +		val |= 0x1 << CFG_TIMER_CTRL_ACK_NAK_SHIFT;
> +		dw_pcie_writel_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF, val);
> +	}
> +
> +	dw_pcie_setup_rc(pp);
> +
> +	clk_set_rate(pcie->core_clk, GEN4_CORE_CLK_FREQ);
> +
> +	/* Assert RST */
> +	val = appl_readl(pcie, APPL_PINMUX);
> +	val &= ~APPL_PINMUX_PEX_RST;
> +	appl_writel(pcie, val, APPL_PINMUX);
> +
> +	usleep_range(100, 200);
> +
> +	/* Enable LTSSM */
> +	val = appl_readl(pcie, APPL_CTRL);
> +	val |= APPL_CTRL_LTSSM_EN;
> +	appl_writel(pcie, val, APPL_CTRL);
> +
> +	/* De-assert RST */
> +	val = appl_readl(pcie, APPL_PINMUX);
> +	val |= APPL_PINMUX_PEX_RST;
> +	appl_writel(pcie, val, APPL_PINMUX);
> +
> +	msleep(100);
> +
> +	val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
> +	while (!(val_w & PCI_EXP_LNKSTA_DLLLA)) {
> +		if (count) {
> +			dev_dbg(pci->dev, "Waiting for link up\n");
> +			usleep_range(1000, 2000);
> +			val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
> +						  PCI_EXP_LNKSTA);
> +			count--;
> +			continue;
> +		}
> +
> +		val = appl_readl(pcie, APPL_DEBUG);
> +		val &= APPL_DEBUG_LTSSM_STATE_MASK;
> +		val >>= APPL_DEBUG_LTSSM_STATE_SHIFT;
> +		tmp = appl_readl(pcie, APPL_LINK_STATUS);
> +		tmp &= APPL_LINK_STATUS_RDLH_LINK_UP;
> +		if (!(val == 0x11 && !tmp)) {
> +			dev_info(pci->dev, "Link is down\n");
> +			return 0;
> +		}
> +
> +		dev_info(pci->dev, "Link is down in DLL");
> +		dev_info(pci->dev, "Trying again with DLFE disabled\n");
> +		/* Disable LTSSM */
> +		val = appl_readl(pcie, APPL_CTRL);
> +		val &= ~APPL_CTRL_LTSSM_EN;
> +		appl_writel(pcie, val, APPL_CTRL);
> +
> +		reset_control_assert(pcie->core_rst);
> +		reset_control_deassert(pcie->core_rst);
> +
> +		offset = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_DLF);
> +		val = dw_pcie_readl_dbi(pci, offset + PCI_DLF_CAP);
> +		val &= ~PCI_DLF_EXCHANGE_ENABLE;
> +		dw_pcie_writel_dbi(pci, offset, val);
> +
> +		/* Retry now with DLF Exchange disabled */
> +		goto core_init;

This goto upwards honestly is a bit horrible. Use some functions
to make the code more readable.

> +	}
> +	dev_dbg(pci->dev, "Link is up\n");
> +
> +	speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
> +		PCI_EXP_LNKSTA_CLS;
> +	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
> +
> +	tegra_pcie_enable_interrupts(pp);
> +
> +	return 0;
> +}
> +
> +static int tegra_pcie_dw_link_up(struct dw_pcie *pci)
> +{
> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> +	u32 val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
> +
> +	return !!(val & PCI_EXP_LNKSTA_DLLLA);

It looks like this can be common code reusable by other DWC drivers ?

Not mandatory, just a hint.

> +}
> +
> +static void tegra_pcie_set_msi_vec_num(struct pcie_port *pp)
> +{
> +	pp->num_vectors = MAX_MSI_IRQS;
> +}
> +
> +static const struct dw_pcie_ops tegra_dw_pcie_ops = {
> +	.link_up = tegra_pcie_dw_link_up,
> +};
> +
> +static struct dw_pcie_host_ops tegra_pcie_dw_host_ops = {
> +	.rd_own_conf = tegra_pcie_dw_rd_own_conf,
> +	.wr_own_conf = tegra_pcie_dw_wr_own_conf,
> +	.host_init = tegra_pcie_dw_host_init,
> +	.set_num_vectors = tegra_pcie_set_msi_vec_num,
> +};
> +
> +static void tegra_pcie_disable_phy(struct tegra_pcie_dw *pcie)
> +{
> +	unsigned int phy_count = pcie->phy_count;
> +
> +	while (phy_count--) {
> +		phy_power_off(pcie->phys[phy_count]);
> +		phy_exit(pcie->phys[phy_count]);
> +	}
> +}
> +
> +static int tegra_pcie_enable_phy(struct tegra_pcie_dw *pcie)
> +{
> +	unsigned int i;
> +	int ret;
> +
> +	for (i = 0; i < pcie->phy_count; i++) {
> +		ret = phy_init(pcie->phys[i]);
> +		if (ret < 0)
> +			goto phy_power_off;
> +
> +		ret = phy_power_on(pcie->phys[i]);
> +		if (ret < 0)
> +			goto phy_exit;
> +	}
> +
> +	return 0;
> +
> +phy_power_off:
> +	while (i--) {
> +		phy_power_off(pcie->phys[i]);
> +phy_exit:
> +		phy_exit(pcie->phys[i]);
> +	}
> +
> +	return ret;
> +}
> +
> +static int tegra_pcie_dw_parse_dt(struct tegra_pcie_dw *pcie)
> +{
> +	struct device_node *np = pcie->dev->of_node;
> +	int ret;
> +
> +	ret = of_property_read_u32(np, "nvidia,aspm-cmrt-us", &pcie->aspm_cmrt);
> +	if (ret < 0) {
> +		dev_info(pcie->dev, "Failed to read ASPM T_cmrt: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = of_property_read_u32(np, "nvidia,aspm-pwr-on-t-us",
> +				   &pcie->aspm_pwr_on_t);
> +	if (ret < 0)
> +		dev_info(pcie->dev, "Failed to read ASPM Power On time: %d\n",
> +			 ret);
> +
> +	ret = of_property_read_u32(np, "nvidia,aspm-l0s-entrance-latency-us",
> +				   &pcie->aspm_l0s_enter_lat);
> +	if (ret < 0)
> +		dev_info(pcie->dev,
> +			 "Failed to read ASPM L0s Entrance latency: %d\n", ret);
> +
> +	ret = of_property_read_u32(np, "num-lanes", &pcie->num_lanes);
> +	if (ret < 0) {
> +		dev_err(pcie->dev, "Failed to read num-lanes: %d\n", ret);
> +		return ret;
> +	}
> +
> +	pcie->max_speed = of_pci_get_max_link_speed(np);
> +
> +	ret = of_property_read_u32_index(np, "nvidia,bpmp", 1, &pcie->cid);
> +	if (ret) {
> +		dev_err(pcie->dev, "Failed to read Controller-ID: %d\n", ret);
> +		return ret;
> +	}
> +
> +	pcie->phy_count = of_property_count_strings(np, "phy-names");
> +	if (pcie->phy_count < 0) {
> +		dev_err(pcie->dev, "Failed to find PHY entries: %d\n",
> +			pcie->phy_count);
> +		return pcie->phy_count;
> +	}
> +
> +	if (of_property_read_bool(np, "nvidia,update-fc-fixup"))
> +		pcie->update_fc_fixup = true;
> +
> +	pcie->supports_clkreq =
> +		of_property_read_bool(pcie->dev->of_node, "supports-clkreq");
> +
> +	pcie->enable_cdm_check =
> +		of_property_read_bool(np, "snps,enable-cdm-check");
> +
> +	return 0;
> +}
> +
> +static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
> +					  bool enable)
> +{
> +	struct mrq_uphy_response resp;
> +	struct tegra_bpmp_message msg;
> +	struct mrq_uphy_request req;
> +	int err;
> +
> +	if (pcie->cid == 5)
> +		return 0;

What's wrong with cid == 5 ? Explain please.

> +	memset(&req, 0, sizeof(req));
> +	memset(&resp, 0, sizeof(resp));
> +
> +	req.cmd = CMD_UPHY_PCIE_CONTROLLER_STATE;
> +	req.controller_state.pcie_controller = pcie->cid;
> +	req.controller_state.enable = enable;
> +
> +	memset(&msg, 0, sizeof(msg));
> +	msg.mrq = MRQ_UPHY;
> +	msg.tx.data = &req;
> +	msg.tx.size = sizeof(req);
> +	msg.rx.data = &resp;
> +	msg.rx.size = sizeof(resp);
> +
> +	if (irqs_disabled())

Can you explain to me what this check is meant to achieve please ?

> +		err = tegra_bpmp_transfer_atomic(pcie->bpmp, &msg);
> +	else
> +		err = tegra_bpmp_transfer(pcie->bpmp, &msg);
> +
> +	return err;
> +}
> +
> +static void tegra_pcie_downstream_dev_to_D0(struct tegra_pcie_dw *pcie)
> +{
> +	struct pcie_port *pp = &pcie->pci.pp;
> +	struct pci_dev *pdev;
> +	struct pci_bus *child;
> +
> +	list_for_each_entry(child, &pp->root_bus->children, node) {
> +		/* Bring downstream devices to D0 if they are not already in */
> +		if (child->parent == pp->root_bus)
> +			break;
> +	}
> +	list_for_each_entry(pdev, &child->devices, bus_list) {
> +		if (PCI_SLOT(pdev->devfn) == 0) {
> +			if (pci_set_power_state(pdev, PCI_D0))
> +				dev_err(pcie->dev,
> +					"Failed to transition %s to D0 state\n",
> +					dev_name(&pdev->dev));
> +		}
> +	}
> +}
> +
> +static int tegra_pcie_config_controller(struct tegra_pcie_dw *pcie,
> +					bool en_hw_hot_rst)
> +{
> +	int ret;
> +	u32 val;
> +
> +	ret = tegra_pcie_bpmp_set_ctrl_state(pcie, true);
> +	if (ret) {
> +		dev_err(pcie->dev,
> +			"Failed to enable controller %u: %d\n", pcie->cid, ret);
> +		return ret;
> +	}
> +
> +	ret = regulator_enable(pcie->pex_ctl_supply);
> +	if (ret < 0) {
> +		dev_err(pcie->dev, "Failed to enable regulator: %d\n", ret);
> +		goto fail_reg_en;
> +	}
> +
> +	ret = clk_prepare_enable(pcie->core_clk);
> +	if (ret) {
> +		dev_err(pcie->dev, "Failed to enable core clock: %d\n", ret);
> +		goto fail_core_clk;
> +	}
> +
> +	ret = reset_control_deassert(pcie->core_apb_rst);
> +	if (ret) {
> +		dev_err(pcie->dev, "Failed to deassert core APB reset: %d\n",
> +			ret);
> +		goto fail_core_apb_rst;
> +	}
> +
> +	if (en_hw_hot_rst) {
> +		/* Enable HW_HOT_RST mode */
> +		val = appl_readl(pcie, APPL_CTRL);
> +		val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
> +			 APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
> +		val |= APPL_CTRL_HW_HOT_RST_EN;
> +		appl_writel(pcie, val, APPL_CTRL);
> +	}
> +
> +	ret = tegra_pcie_enable_phy(pcie);
> +	if (ret) {
> +		dev_err(pcie->dev, "Failed to enable PHY: %d\n", ret);
> +		goto fail_phy;
> +	}
> +
> +	/* Update CFG base address */
> +	appl_writel(pcie, pcie->dbi_res->start & APPL_CFG_BASE_ADDR_MASK,
> +		    APPL_CFG_BASE_ADDR);
> +
> +	/* Configure this core for RP mode operation */
> +	appl_writel(pcie, APPL_DM_TYPE_RP, APPL_DM_TYPE);
> +
> +	appl_writel(pcie, 0x0, APPL_CFG_SLCG_OVERRIDE);
> +
> +	val = appl_readl(pcie, APPL_CTRL);
> +	appl_writel(pcie, val | APPL_CTRL_SYS_PRE_DET_STATE, APPL_CTRL);
> +
> +	val = appl_readl(pcie, APPL_CFG_MISC);
> +	val |= (APPL_CFG_MISC_ARCACHE_VAL << APPL_CFG_MISC_ARCACHE_SHIFT);
> +	appl_writel(pcie, val, APPL_CFG_MISC);
> +
> +	if (!pcie->supports_clkreq) {
> +		val = appl_readl(pcie, APPL_PINMUX);
> +		val |= APPL_PINMUX_CLKREQ_OUT_OVRD_EN;
> +		val |= APPL_PINMUX_CLKREQ_OUT_OVRD;
> +		appl_writel(pcie, val, APPL_PINMUX);
> +	}
> +
> +	/* Update iATU_DMA base address */
> +	appl_writel(pcie,
> +		    pcie->atu_dma_res->start & APPL_CFG_IATU_DMA_BASE_ADDR_MASK,
> +		    APPL_CFG_IATU_DMA_BASE_ADDR);
> +
> +	reset_control_deassert(pcie->core_rst);
> +
> +	pcie->pcie_cap_base = dw_pcie_find_capability(&pcie->pci,
> +						      PCI_CAP_ID_EXP);
> +
> +#if defined(CONFIG_PCIEASPM)
> +	/* Disable ASPM-L1SS advertisement as there is no CLKREQ routing */
> +	if (!pcie->supports_clkreq) {
> +		disable_aspm_l11(pcie);
> +		disable_aspm_l12(pcie);
> +	}
> +#endif
> +	return ret;
> +
> +fail_phy:
> +	reset_control_assert(pcie->core_apb_rst);
> +fail_core_apb_rst:
> +	clk_disable_unprepare(pcie->core_clk);
> +fail_core_clk:
> +	regulator_disable(pcie->pex_ctl_supply);
> +fail_reg_en:
> +	tegra_pcie_bpmp_set_ctrl_state(pcie, false);
> +
> +	return ret;
> +}
> +
> +static int __deinit_controller(struct tegra_pcie_dw *pcie)
> +{
> +	int ret;
> +
> +	ret = reset_control_assert(pcie->core_rst);
> +	if (ret) {
> +		dev_err(pcie->dev, "Failed to assert \"core\" reset: %d\n",
> +			ret);
> +		return ret;
> +	}
> +	tegra_pcie_disable_phy(pcie);
> +	ret = reset_control_assert(pcie->core_apb_rst);
> +	if (ret) {
> +		dev_err(pcie->dev, "Failed to assert APB reset: %d\n", ret);
> +		return ret;
> +	}
> +	clk_disable_unprepare(pcie->core_clk);
> +	ret = regulator_disable(pcie->pex_ctl_supply);
> +	if (ret) {
> +		dev_err(pcie->dev, "Failed to disable regulator: %d\n", ret);
> +		return ret;
> +	}
> +	ret = tegra_pcie_bpmp_set_ctrl_state(pcie, false);
> +	if (ret) {
> +		dev_err(pcie->dev, "Failed to disable controller %d: %d\n",
> +			pcie->cid, ret);
> +		return ret;
> +	}
> +	return ret;
> +}
> +
> +static int tegra_pcie_init_controller(struct tegra_pcie_dw *pcie)
> +{
> +	struct dw_pcie *pci = &pcie->pci;
> +	struct pcie_port *pp = &pci->pp;
> +	int ret;
> +
> +	ret = tegra_pcie_config_controller(pcie, false);
> +	if (ret < 0)
> +		return ret;
> +
> +	pp->root_bus_nr = -1;
> +	pp->ops = &tegra_pcie_dw_host_ops;
> +
> +	ret = dw_pcie_host_init(pp);
> +	if (ret < 0) {
> +		dev_err(pcie->dev, "Failed to add PCIe port: %d\n", ret);
> +		goto fail_host_init;
> +	}
> +
> +	return 0;
> +
> +fail_host_init:
> +	return __deinit_controller(pcie);
> +}
> +
> +static int tegra_pcie_try_link_l2(struct tegra_pcie_dw *pcie)
> +{
> +	u32 val;
> +
> +	if (!tegra_pcie_dw_link_up(&pcie->pci))
> +		return 0;
> +
> +	val = appl_readl(pcie, APPL_RADM_STATUS);
> +	val |= APPL_PM_XMT_TURNOFF_STATE;
> +	appl_writel(pcie, val, APPL_RADM_STATUS);
> +
> +	return readl_poll_timeout_atomic(pcie->appl_base + APPL_DEBUG, val,
> +				 val & APPL_DEBUG_PM_LINKST_IN_L2_LAT,
> +				 1, PME_ACK_TIMEOUT);
> +}
> +
> +static void tegra_pcie_dw_pme_turnoff(struct tegra_pcie_dw *pcie)
> +{
> +	u32 data;
> +	int err;
> +
> +	if (!tegra_pcie_dw_link_up(&pcie->pci)) {
> +		dev_dbg(pcie->dev, "PCIe link is not up...!\n");
> +		return;
> +	}
> +
> +	if (tegra_pcie_try_link_l2(pcie)) {
> +		dev_info(pcie->dev, "Link didn't transition to L2 state\n");
> +		/*
> +		 * TX lane clock freq will reset to Gen1 only if link is in L2
> +		 * or detect state.
> +		 * So apply pex_rst to end point to force RP to go into detect
> +		 * state
> +		 */
> +		data = appl_readl(pcie, APPL_PINMUX);
> +		data &= ~APPL_PINMUX_PEX_RST;
> +		appl_writel(pcie, data, APPL_PINMUX);
> +
> +		err = readl_poll_timeout_atomic(pcie->appl_base + APPL_DEBUG,
> +						data,
> +						((data &
> +						APPL_DEBUG_LTSSM_STATE_MASK) >>
> +						APPL_DEBUG_LTSSM_STATE_SHIFT) ==
> +						LTSSM_STATE_PRE_DETECT,
> +						1, LTSSM_TIMEOUT);
> +		if (err) {
> +			dev_info(pcie->dev, "Link didn't go to detect state\n");
> +		} else {
> +			/* Disable LTSSM after link is in detect state */
> +			data = appl_readl(pcie, APPL_CTRL);
> +			data &= ~APPL_CTRL_LTSSM_EN;
> +			appl_writel(pcie, data, APPL_CTRL);
> +		}
> +	}
> +	/*
> +	 * DBI registers may not be accessible after this as PLL-E would be
> +	 * down depending on how CLKREQ is pulled by end point
> +	 */
> +	data = appl_readl(pcie, APPL_PINMUX);
> +	data |= (APPL_PINMUX_CLKREQ_OVERRIDE_EN | APPL_PINMUX_CLKREQ_OVERRIDE);
> +	/* Cut REFCLK to slot */
> +	data |= APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE_EN;
> +	data &= ~APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE;
> +	appl_writel(pcie, data, APPL_PINMUX);
> +}
> +
> +static int tegra_pcie_deinit_controller(struct tegra_pcie_dw *pcie)
> +{
> +	/*
> +	 * link doesn't go into L2 state with some of the endpoints with Tegra
> +	 * if they are not in D0 state. So, need to make sure that immediate
> +	 * downstream devices are in D0 state before sending PME_TurnOff to put
> +	 * link into L2 state
> +	 */
> +	tegra_pcie_downstream_dev_to_D0(pcie);
> +	dw_pcie_host_deinit(&pcie->pci.pp);
> +	tegra_pcie_dw_pme_turnoff(pcie);
> +	return __deinit_controller(pcie);
> +}
> +
> +static int tegra_pcie_config_rp(struct tegra_pcie_dw *pcie)
> +{
> +	struct pcie_port *pp = &pcie->pci.pp;
> +	struct device *dev = pcie->dev;
> +	char *name;
> +	int ret;
> +
> +	if (IS_ENABLED(CONFIG_PCI_MSI)) {
> +		pp->msi_irq = of_irq_get_byname(dev->of_node, "msi");
> +		if (!pp->msi_irq) {
> +			dev_err(dev, "Failed to get MSI interrupt\n");
> +			return -ENODEV;
> +		}
> +	}
> +
> +	pm_runtime_enable(dev);
> +	ret = pm_runtime_get_sync(dev);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to get runtime sync for PCIe dev: %d\n",
> +			ret);
> +		pm_runtime_disable(dev);
> +		return ret;
> +	}
> +
> +	tegra_pcie_init_controller(pcie);
> +
> +	pcie->link_state = tegra_pcie_dw_link_up(&pcie->pci);
> +
> +	if (!pcie->link_state) {
> +		ret = -ENOMEDIUM;
> +		goto fail_host_init;
> +	}
> +
> +	name = devm_kasprintf(dev, GFP_KERNEL, "%pOFP", dev->of_node);
> +	if (!name) {
> +		ret = -ENOMEM;
> +		goto fail_host_init;
> +	}
> +
> +	pcie->debugfs = debugfs_create_dir(name, NULL);
> +	if (!pcie->debugfs)
> +		dev_err(dev, "Failed to create debugfs\n");
> +	else
> +		init_debugfs(pcie);
> +
> +	return ret;
> +
> +fail_host_init:
> +	tegra_pcie_deinit_controller(pcie);
> +	pm_runtime_put_sync(dev);
> +	pm_runtime_disable(dev);
> +	return ret;
> +}
> +
> +static const struct tegra_pcie_soc tegra_pcie_rc_of_data = {
> +	.mode = DW_PCIE_RC_TYPE,
> +};
> +
> +static const struct of_device_id tegra_pcie_dw_of_match[] = {
> +	{
> +		.compatible = "nvidia,tegra194-pcie",
> +		.data = &tegra_pcie_rc_of_data,
> +	},
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, tegra_pcie_dw_of_match);
> +
> +static int tegra_pcie_dw_probe(struct platform_device *pdev)
> +{
> +	const struct tegra_pcie_soc *data;
> +	struct device *dev = &pdev->dev;
> +	struct resource *atu_dma_res;
> +	struct tegra_pcie_dw *pcie;
> +	struct resource *dbi_res;
> +	struct pcie_port *pp;
> +	struct dw_pcie *pci;
> +	struct phy **phys;
> +	char *name;
> +	int ret;
> +	u32 i;
> +
> +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> +	if (!pcie)
> +		return -ENOMEM;
> +
> +	pci = &pcie->pci;
> +	pci->dev = &pdev->dev;
> +	pci->ops = &tegra_dw_pcie_ops;
> +	pp = &pci->pp;
> +	pcie->dev = &pdev->dev;
> +
> +	data = (struct tegra_pcie_soc *)of_device_get_match_data(dev);
> +	if (!data)
> +		return -EINVAL;
> +	pcie->mode = (enum dw_pcie_device_mode)data->mode;
> +
> +	ret = tegra_pcie_dw_parse_dt(pcie);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to parse device tree: %d\n", ret);
> +		return ret;
> +	}
> +
> +	pcie->pex_ctl_supply = devm_regulator_get(dev, "vddio-pex-ctl");
> +	if (IS_ERR(pcie->pex_ctl_supply)) {
> +		dev_err(dev, "Failed to get regulator: %ld\n",
> +			PTR_ERR(pcie->pex_ctl_supply));
> +		return PTR_ERR(pcie->pex_ctl_supply);
> +	}
> +
> +	pcie->core_clk = devm_clk_get(dev, "core");
> +	if (IS_ERR(pcie->core_clk)) {
> +		dev_err(dev, "Failed to get core clock: %ld\n",
> +			PTR_ERR(pcie->core_clk));
> +		return PTR_ERR(pcie->core_clk);
> +	}
> +
> +	pcie->appl_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> +						      "appl");
> +	if (!pcie->appl_res) {
> +		dev_err(dev, "Failed to find \"appl\" region\n");
> +		return PTR_ERR(pcie->appl_res);
> +	}
> +	pcie->appl_base = devm_ioremap_resource(dev, pcie->appl_res);
> +	if (IS_ERR(pcie->appl_base))
> +		return PTR_ERR(pcie->appl_base);
> +
> +	pcie->core_apb_rst = devm_reset_control_get(dev, "apb");
> +	if (IS_ERR(pcie->core_apb_rst)) {
> +		dev_err(dev, "Failed to get APB reset: %ld\n",
> +			PTR_ERR(pcie->core_apb_rst));
> +		return PTR_ERR(pcie->core_apb_rst);
> +	}
> +
> +	phys = devm_kcalloc(dev, pcie->phy_count, sizeof(*phys), GFP_KERNEL);
> +	if (!phys)
> +		return PTR_ERR(phys);
> +
> +	for (i = 0; i < pcie->phy_count; i++) {
> +		name = kasprintf(GFP_KERNEL, "p2u-%u", i);
> +		if (!name) {
> +			dev_err(dev, "Failed to create P2U string\n");
> +			return -ENOMEM;
> +		}
> +		phys[i] = devm_phy_get(dev, name);
> +		kfree(name);
> +		if (IS_ERR(phys[i])) {
> +			ret = PTR_ERR(phys[i]);
> +			dev_err(dev, "Failed to get PHY: %d\n", ret);
> +			return ret;
> +		}
> +	}
> +
> +	pcie->phys = phys;
> +
> +	dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
> +	if (!dbi_res) {
> +		dev_err(dev, "Failed to find \"dbi\" region\n");
> +		return PTR_ERR(dbi_res);
> +	}
> +	pcie->dbi_res = dbi_res;
> +
> +	pci->dbi_base = devm_ioremap_resource(dev, dbi_res);
> +	if (IS_ERR(pci->dbi_base))
> +		return PTR_ERR(pci->dbi_base);
> +
> +	/* Tegra HW locates DBI2 at a fixed offset from DBI */
> +	pci->dbi_base2 = pci->dbi_base + 0x1000;
> +
> +	atu_dma_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> +						   "atu_dma");
> +	if (!atu_dma_res) {
> +		dev_err(dev, "Failed to find \"atu_dma\" region\n");
> +		return PTR_ERR(atu_dma_res);
> +	}
> +	pcie->atu_dma_res = atu_dma_res;
> +	pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);
> +	if (IS_ERR(pci->atu_base))
> +		return PTR_ERR(pci->atu_base);
> +
> +	pcie->core_rst = devm_reset_control_get(dev, "core");
> +	if (IS_ERR(pcie->core_rst)) {
> +		dev_err(dev, "Failed to get core reset: %ld\n",
> +			PTR_ERR(pcie->core_rst));
> +		return PTR_ERR(pcie->core_rst);
> +	}
> +
> +	pp->irq = platform_get_irq_byname(pdev, "intr");
> +	if (!pp->irq) {
> +		dev_err(dev, "Failed to get \"intr\" interrupt\n");
> +		return -ENODEV;
> +	}
> +
> +	ret = devm_request_irq(dev, pp->irq, tegra_pcie_irq_handler,
> +			       IRQF_SHARED, "tegra-pcie-intr", pcie);
> +	if (ret) {
> +		dev_err(dev, "Failed to request IRQ %d: %d\n", pp->irq, ret);
> +		return ret;
> +	}
> +
> +	pcie->bpmp = tegra_bpmp_get(dev);
> +	if (IS_ERR(pcie->bpmp))
> +		return PTR_ERR(pcie->bpmp);
> +
> +	platform_set_drvdata(pdev, pcie);
> +
> +	if (pcie->mode == DW_PCIE_RC_TYPE) {
> +		ret = tegra_pcie_config_rp(pcie);
> +		if (ret && ret != -ENOMEDIUM)
> +			goto fail;
> +		else
> +			return 0;

So if the link is not up we still go ahead and make probe
succeed. What for ?

> +	}
> +
> +fail:
> +	tegra_bpmp_put(pcie->bpmp);
> +	return ret;
> +}
> +
> +static int tegra_pcie_dw_remove(struct platform_device *pdev)
> +{
> +	struct tegra_pcie_dw *pcie = platform_get_drvdata(pdev);
> +
> +	if (pcie->mode != DW_PCIE_RC_TYPE)
> +		return 0;
> +
> +	if (!pcie->link_state)
> +		return 0;
> +
> +	debugfs_remove_recursive(pcie->debugfs);
> +	tegra_pcie_deinit_controller(pcie);
> +	pm_runtime_put_sync(pcie->dev);
> +	pm_runtime_disable(pcie->dev);
> +	tegra_bpmp_put(pcie->bpmp);
> +
> +	return 0;
> +}
> +
> +static int tegra_pcie_dw_suspend_late(struct device *dev)
> +{
> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
> +	u32 val;
> +
> +	if (!pcie->link_state)
> +		return 0;
> +
> +	/* Enable HW_HOT_RST mode */
> +	val = appl_readl(pcie, APPL_CTRL);
> +	val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
> +		 APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
> +	val |= APPL_CTRL_HW_HOT_RST_EN;
> +	appl_writel(pcie, val, APPL_CTRL);
> +
> +	return 0;
> +}
> +
> +static int tegra_pcie_dw_suspend_noirq(struct device *dev)
> +{
> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
> +
> +	if (!pcie->link_state)
> +		return 0;
> +
> +	/* Save MSI interrupt vector */
> +	pcie->msi_ctrl_int = dw_pcie_readl_dbi(&pcie->pci,
> +					       PORT_LOGIC_MSI_CTRL_INT_0_EN);
> +	tegra_pcie_downstream_dev_to_D0(pcie);

I think this requires some comments. AFAIU this is allowed by
the PCI specs (PCI Express Base 4.0 r1.0 September 29-2017,
5.2 Link State Power Management). However, I would like to
understand how this plays with the D state the devices are left
in upon system suspend.

"As the following example illustrates, it is also possible to remove
power without first placing all Functions into D3Hot".

I assume that's what happens on this platform to allow L2 entry but
again, this needs clarification.

Lorenzo

> +	tegra_pcie_dw_pme_turnoff(pcie);
> +	return __deinit_controller(pcie);
> +}
> +
> +static int tegra_pcie_dw_resume_noirq(struct device *dev)
> +{
> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
> +	int ret;
> +
> +	if (!pcie->link_state)
> +		return 0;
> +
> +	ret = tegra_pcie_config_controller(pcie, true);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = tegra_pcie_dw_host_init(&pcie->pci.pp);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to init host: %d\n", ret);
> +		goto fail_host_init;
> +	}
> +
> +	/* Restore MSI interrupt vector */
> +	dw_pcie_writel_dbi(&pcie->pci, PORT_LOGIC_MSI_CTRL_INT_0_EN,
> +			   pcie->msi_ctrl_int);
> +
> +	return 0;
> +fail_host_init:
> +	return __deinit_controller(pcie);
> +}
> +
> +static int tegra_pcie_dw_resume_early(struct device *dev)
> +{
> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
> +	u32 val;
> +
> +	if (!pcie->link_state)
> +		return 0;
> +
> +	/* Disable HW_HOT_RST mode */
> +	val = appl_readl(pcie, APPL_CTRL);
> +	val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
> +		 APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
> +	val |= APPL_CTRL_HW_HOT_RST_MODE_IMDT_RST <<
> +	       APPL_CTRL_HW_HOT_RST_MODE_SHIFT;
> +	val &= ~APPL_CTRL_HW_HOT_RST_EN;
> +	appl_writel(pcie, val, APPL_CTRL);
> +
> +	return 0;
> +}
> +
> +static void tegra_pcie_dw_shutdown(struct platform_device *pdev)
> +{
> +	struct tegra_pcie_dw *pcie = platform_get_drvdata(pdev);
> +
> +	if (pcie->mode != DW_PCIE_RC_TYPE)
> +		return;
> +
> +	if (!pcie->link_state)
> +		return;
> +
> +	debugfs_remove_recursive(pcie->debugfs);
> +	tegra_pcie_downstream_dev_to_D0(pcie);
> +
> +	disable_irq(pcie->pci.pp.irq);
> +	if (IS_ENABLED(CONFIG_PCI_MSI))
> +		disable_irq(pcie->pci.pp.msi_irq);
> +
> +	tegra_pcie_dw_pme_turnoff(pcie);
> +	__deinit_controller(pcie);
> +}
> +
> +static const struct dev_pm_ops tegra_pcie_dw_pm_ops = {
> +	.suspend_late = tegra_pcie_dw_suspend_late,
> +	.suspend_noirq = tegra_pcie_dw_suspend_noirq,
> +	.resume_noirq = tegra_pcie_dw_resume_noirq,
> +	.resume_early = tegra_pcie_dw_resume_early,
> +};
> +
> +static struct platform_driver tegra_pcie_dw_driver = {
> +	.probe = tegra_pcie_dw_probe,
> +	.remove = tegra_pcie_dw_remove,
> +	.shutdown = tegra_pcie_dw_shutdown,
> +	.driver = {
> +		.name	= "tegra194-pcie",
> +		.pm = &tegra_pcie_dw_pm_ops,
> +		.of_match_table = tegra_pcie_dw_of_match,
> +	},
> +};
> +module_platform_driver(tegra_pcie_dw_driver);
> +
> +MODULE_AUTHOR("Vidya Sagar <vidyas@nvidia.com>");
> +MODULE_DESCRIPTION("NVIDIA PCIe host controller driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.17.1
>

On 7/11/2019 6:24 PM, Lorenzo Pieralisi wrote:
> On Wed, Jul 10, 2019 at 11:52:12AM +0530, Vidya Sagar wrote:
> 
> [...]
> 
>> diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
>> new file mode 100644
>> index 000000000000..189779edd976
>> --- /dev/null
>> +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
>> @@ -0,0 +1,1632 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +/*
>> + * PCIe host controller driver for Tegra194 SoC
>> + *
>> + * Copyright (C) 2019 NVIDIA Corporation.
>> + *
>> + * Author: Vidya Sagar <vidyas@nvidia.com>
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/debugfs.h>
>> +#include <linux/delay.h>
>> +#include <linux/gpio.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/iopoll.h>
>> +#include <linux/kernel.h>
>> +#include <linux/kfifo.h>
>> +#include <linux/kthread.h>
> 
> What do you need these two headers for ?
These were added for a different reason. They are not required
and I'll remove them.

> 
> [...]
> 
>> +struct tegra_pcie_dw {
>> +	struct device *dev;
>> +	struct resource *appl_res;
>> +	struct resource *dbi_res;
>> +	struct resource *atu_dma_res;
>> +	void __iomem *appl_base;
>> +	struct clk *core_clk;
>> +	struct reset_control *core_apb_rst;
>> +	struct reset_control *core_rst;
>> +	struct dw_pcie pci;
>> +	enum dw_pcie_device_mode mode;
>> +	struct tegra_bpmp *bpmp;
>> +
>> +	bool supports_clkreq;
>> +	bool enable_cdm_check;
>> +	u8 init_link_width;
>> +	bool link_state;
>> +	u32 msi_ctrl_int;
>> +	u32 num_lanes;
>> +	u32 max_speed;
>> +	u32 cid;
>> +	bool update_fc_fixup;
>> +	u32 cfg_link_cap_l1sub;
>> +	u32 pcie_cap_base;
>> +	u32 aspm_cmrt;
>> +	u32 aspm_pwr_on_t;
>> +	u32 aspm_l0s_enter_lat;o
> 
> Nit: You should try to group variables according to their usage,
> it would make sense to group booleans together.
Ok.

> 
>> +	struct regulator *pex_ctl_supply;
>> +
>> +	unsigned int phy_count;
>> +	struct phy **phys;
>> +
>> +	struct dentry *debugfs;
>> +};
>> +
>> +static inline struct tegra_pcie_dw *to_tegra_pcie(struct dw_pcie *pci)
>> +{
>> +	return container_of(pci, struct tegra_pcie_dw, pci);
>> +}
>> +
>> +static inline void appl_writel(struct tegra_pcie_dw *pcie, const u32 value,
>> +			       const u32 reg)
>> +{
>> +	writel_relaxed(value, pcie->appl_base + reg);
>> +}
>> +
>> +static inline u32 appl_readl(struct tegra_pcie_dw *pcie, const u32 reg)
>> +{
>> +	return readl_relaxed(pcie->appl_base + reg);
>> +}
>> +
>> +struct tegra_pcie_soc {
>> +	enum dw_pcie_device_mode mode;
>> +};
>> +
>> +static void apply_bad_link_workaround(struct pcie_port *pp)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
>> +	u32 current_link_width;
>> +	u16 val;
>> +
>> +	/*
>> +	 * NOTE:- Since this scenario is uncommon and link as such is not
>> +	 * stable anyway, not waiting to confirm if link is really
>> +	 * transitioning to Gen-2 speed
>> +	 */
>> +	val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
>> +	if (val & PCI_EXP_LNKSTA_LBMS) {
>> +		current_link_width = (val & PCI_EXP_LNKSTA_NLW) >>
>> +				     PCI_EXP_LNKSTA_NLW_SHIFT;
>> +		if (pcie->init_link_width > current_link_width) {
>> +			dev_warn(pci->dev, "PCIe link is bad, width reduced\n");
>> +			val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
>> +						PCI_EXP_LNKCTL2);
>> +			val &= ~PCI_EXP_LNKCTL2_TLS;
>> +			val |= PCI_EXP_LNKCTL2_TLS_2_5GT;
>> +			dw_pcie_writew_dbi(pci, pcie->pcie_cap_base +
>> +					   PCI_EXP_LNKCTL2, val);
>> +
>> +			val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
>> +						PCI_EXP_LNKCTL);
>> +			val |= PCI_EXP_LNKCTL_RL;
>> +			dw_pcie_writew_dbi(pci, pcie->pcie_cap_base +
>> +					   PCI_EXP_LNKCTL, val);
>> +		}
>> +	}
>> +}
>> +
>> +static irqreturn_t tegra_pcie_rp_irq_handler(struct tegra_pcie_dw *pcie)
>> +{
>> +	struct dw_pcie *pci = &pcie->pci;
>> +	struct pcie_port *pp = &pci->pp;
>> +	u32 val, tmp;
>> +	u16 val_w;
>> +
>> +	val = appl_readl(pcie, APPL_INTR_STATUS_L0);
>> +	if (val & APPL_INTR_STATUS_L0_LINK_STATE_INT) {
>> +		val = appl_readl(pcie, APPL_INTR_STATUS_L1_0_0);
>> +		if (val & APPL_INTR_STATUS_L1_0_0_LINK_REQ_RST_NOT_CHGED) {
>> +			appl_writel(pcie, val, APPL_INTR_STATUS_L1_0_0);
>> +
>> +			/* SBR & Surprise Link Down WAR */
>> +			val = appl_readl(pcie, APPL_CAR_RESET_OVRD);
>> +			val &= ~APPL_CAR_RESET_OVRD_CYA_OVERRIDE_CORE_RST_N;
>> +			appl_writel(pcie, val, APPL_CAR_RESET_OVRD);
>> +			udelay(1);
>> +			val = appl_readl(pcie, APPL_CAR_RESET_OVRD);
>> +			val |= APPL_CAR_RESET_OVRD_CYA_OVERRIDE_CORE_RST_N;
>> +			appl_writel(pcie, val, APPL_CAR_RESET_OVRD);
>> +
>> +			val = dw_pcie_readl_dbi(pci, PORT_LOGIC_GEN2_CTRL);
>> +			val |= PORT_LOGIC_GEN2_CTRL_DIRECT_SPEED_CHANGE;
>> +			dw_pcie_writel_dbi(pci, PORT_LOGIC_GEN2_CTRL, val);
>> +		}
>> +	}
>> +
>> +	if (val & APPL_INTR_STATUS_L0_INT_INT) {
>> +		val = appl_readl(pcie, APPL_INTR_STATUS_L1_8_0);
>> +		if (val & APPL_INTR_STATUS_L1_8_0_AUTO_BW_INT_STS) {
>> +			appl_writel(pcie,
>> +				    APPL_INTR_STATUS_L1_8_0_AUTO_BW_INT_STS,
>> +				    APPL_INTR_STATUS_L1_8_0);
>> +			apply_bad_link_workaround(pp);
>> +		}
>> +		if (val & APPL_INTR_STATUS_L1_8_0_BW_MGT_INT_STS) {
>> +			appl_writel(pcie,
>> +				    APPL_INTR_STATUS_L1_8_0_BW_MGT_INT_STS,
>> +				    APPL_INTR_STATUS_L1_8_0);
>> +
>> +			val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
>> +						  PCI_EXP_LNKSTA);
>> +			dev_dbg(pci->dev, "Link Speed : Gen-%u\n", val_w &
>> +				PCI_EXP_LNKSTA_CLS);
>> +		}
>> +	}
>> +
>> +	val = appl_readl(pcie, APPL_INTR_STATUS_L0);
>> +	if (val & APPL_INTR_STATUS_L0_CDM_REG_CHK_INT) {
>> +		val = appl_readl(pcie, APPL_INTR_STATUS_L1_18);
>> +		tmp = dw_pcie_readl_dbi(pci, PCIE_PL_CHK_REG_CONTROL_STATUS);
>> +		if (val & APPL_INTR_STATUS_L1_18_CDM_REG_CHK_CMPLT) {
>> +			dev_info(pci->dev, "CDM check complete\n");
>> +			tmp |= PCIE_PL_CHK_REG_CHK_REG_COMPLETE;
>> +		}
>> +		if (val & APPL_INTR_STATUS_L1_18_CDM_REG_CHK_CMP_ERR) {
>> +			dev_err(pci->dev, "CDM comparison mismatch\n");
>> +			tmp |= PCIE_PL_CHK_REG_CHK_REG_COMPARISON_ERROR;
>> +		}
>> +		if (val & APPL_INTR_STATUS_L1_18_CDM_REG_CHK_LOGIC_ERR) {
>> +			dev_err(pci->dev, "CDM Logic error\n");
>> +			tmp |= PCIE_PL_CHK_REG_CHK_REG_LOGIC_ERROR;
>> +		}
>> +		dw_pcie_writel_dbi(pci, PCIE_PL_CHK_REG_CONTROL_STATUS, tmp);
>> +		tmp = dw_pcie_readl_dbi(pci, PCIE_PL_CHK_REG_ERR_ADDR);
>> +		dev_err(pci->dev, "CDM Error Address Offset = 0x%08X\n", tmp);
>> +	}
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +static irqreturn_t tegra_pcie_irq_handler(int irq, void *arg)
>> +{
>> +	struct tegra_pcie_dw *pcie = arg;
>> +
>> +	if (pcie->mode == DW_PCIE_RC_TYPE)
>> +		return tegra_pcie_rp_irq_handler(pcie);
> 
> What's the point of registering the handler if mode != DW_PCIE_RC_TYPE ?
Currently this driver supports only root port mode but we have a plan to add
support for endpoint mode (as Tegra194 as dual mode controllers) also in future
and when that happens, we'll have a corresponding tegra_pcie_ep_irq_handler()
to take care of ep specific interrupts.

> 
>> +	return IRQ_NONE;
>> +}
>> +
>> +static int tegra_pcie_dw_rd_own_conf(struct pcie_port *pp, int where, int size,
>> +				     u32 *val)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> +
>> +	/*
>> +	 * This is an endpoint mode specific register happen to appear even
>> +	 * when controller is operating in root port mode and system hangs
>> +	 * when it is accessed with link being in ASPM-L1 state.
>> +	 * So skip accessing it altogether
>> +	 */
>> +	if (where == PORT_LOGIC_MSIX_DOORBELL) {
>> +		*val = 0x00000000;
>> +		return PCIBIOS_SUCCESSFUL;
>> +	}
>> +
>> +	return dw_pcie_read(pci->dbi_base + where, size, val);
>> +}
>> +
>> +static int tegra_pcie_dw_wr_own_conf(struct pcie_port *pp, int where, int size,
>> +				     u32 val)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> +
>> +	/*
>> +	 * This is an endpoint mode specific register happen to appear even
>> +	 * when controller is operating in root port mode and system hangs
>> +	 * when it is accessed with link being in ASPM-L1 state.
>> +	 * So skip accessing it altogether
>> +	 */
>> +	if (where == PORT_LOGIC_MSIX_DOORBELL)
>> +		return PCIBIOS_SUCCESSFUL;
>> +
>> +	return dw_pcie_write(pci->dbi_base + where, size, val);
>> +}
>> +
>> +#if defined(CONFIG_PCIEASPM)
>> +static void disable_aspm_l11(struct tegra_pcie_dw *pcie)
>> +{
>> +	u32 val;
>> +
>> +	val = dw_pcie_readl_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub);
>> +	val &= ~PCI_L1SS_CAP_ASPM_L1_1;
>> +	dw_pcie_writel_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub, val);
>> +}
>> +
>> +static void disable_aspm_l12(struct tegra_pcie_dw *pcie)
>> +{
>> +	u32 val;
>> +
>> +	val = dw_pcie_readl_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub);
>> +	val &= ~PCI_L1SS_CAP_ASPM_L1_2;
>> +	dw_pcie_writel_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub, val);
>> +}
>> +
>> +static inline u32 event_counter_prog(struct tegra_pcie_dw *pcie, u32 event)
>> +{
>> +	u32 val;
>> +
>> +	val = dw_pcie_readl_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid]);
>> +	val &= ~(EVENT_COUNTER_EVENT_SEL_MASK << EVENT_COUNTER_EVENT_SEL_SHIFT);
>> +	val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
>> +	val |= event << EVENT_COUNTER_EVENT_SEL_SHIFT;
>> +	val |= EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
>> +	dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid], val);
>> +	val = dw_pcie_readl_dbi(&pcie->pci, event_cntr_data_offset[pcie->cid]);
>> +	return val;
>> +}
>> +
>> +static int aspm_state_cnt(struct seq_file *s, void *data)
>> +{
>> +	struct tegra_pcie_dw *pcie = (struct tegra_pcie_dw *)
>> +				     dev_get_drvdata(s->private);
>> +	u32 val;
>> +
>> +	seq_printf(s, "Tx L0s entry count : %u\n",
>> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_Tx_L0S));
>> +
>> +	seq_printf(s, "Rx L0s entry count : %u\n",
>> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_Rx_L0S));
>> +
>> +	seq_printf(s, "Link L1 entry count : %u\n",
>> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1));
>> +
>> +	seq_printf(s, "Link L1.1 entry count : %u\n",
>> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1_1));
>> +
>> +	seq_printf(s, "Link L1.2 entry count : %u\n",
>> +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1_2));
>> +
>> +	/* Clear all counters */
>> +	dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid],
>> +			   EVENT_COUNTER_ALL_CLEAR);
>> +
>> +	/* Re-enable counting */
>> +	val = EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
>> +	val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
>> +	dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid], val);
>> +
>> +	return 0;
>> +}
>> +#endif
>> +
>> +static int init_debugfs(struct tegra_pcie_dw *pcie)
>> +{
>> +#if defined(CONFIG_PCIEASPM)
>> +	struct dentry *d;
>> +
>> +	d = debugfs_create_devm_seqfile(pcie->dev, "aspm_state_cnt",
>> +					pcie->debugfs, aspm_state_cnt);
>> +	if (IS_ERR_OR_NULL(d))
>> +		dev_err(pcie->dev,
>> +			"Failed to create debugfs file \"aspm_state_cnt\"\n");
>> +#endif
>> +	return 0;
>> +}
>> +
>> +static void tegra_pcie_enable_system_interrupts(struct pcie_port *pp)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
>> +	u32 val;
>> +	u16 val_w;
>> +
>> +	val = appl_readl(pcie, APPL_INTR_EN_L0_0);
>> +	val |= APPL_INTR_EN_L0_0_LINK_STATE_INT_EN;
>> +	appl_writel(pcie, val, APPL_INTR_EN_L0_0);
>> +
>> +	val = appl_readl(pcie, APPL_INTR_EN_L1_0_0);
>> +	val |= APPL_INTR_EN_L1_0_0_LINK_REQ_RST_NOT_INT_EN;
>> +	appl_writel(pcie, val, APPL_INTR_EN_L1_0_0);
>> +
>> +	if (pcie->enable_cdm_check) {
>> +		val = appl_readl(pcie, APPL_INTR_EN_L0_0);
>> +		val |= APPL_INTR_EN_L0_0_CDM_REG_CHK_INT_EN;
>> +		appl_writel(pcie, val, APPL_INTR_EN_L0_0);
>> +
>> +		val = appl_readl(pcie, APPL_INTR_EN_L1_18);
>> +		val |= APPL_INTR_EN_L1_18_CDM_REG_CHK_CMP_ERR;
>> +		val |= APPL_INTR_EN_L1_18_CDM_REG_CHK_LOGIC_ERR;
>> +		appl_writel(pcie, val, APPL_INTR_EN_L1_18);
>> +	}
>> +
>> +	val_w = dw_pcie_readw_dbi(&pcie->pci, pcie->pcie_cap_base +
>> +				  PCI_EXP_LNKSTA);
>> +	pcie->init_link_width = (val_w & PCI_EXP_LNKSTA_NLW) >>
>> +				PCI_EXP_LNKSTA_NLW_SHIFT;
>> +
>> +	val_w = dw_pcie_readw_dbi(&pcie->pci, pcie->pcie_cap_base +
>> +				  PCI_EXP_LNKCTL);
>> +	val_w |= PCI_EXP_LNKCTL_LBMIE;
>> +	dw_pcie_writew_dbi(&pcie->pci, pcie->pcie_cap_base + PCI_EXP_LNKCTL,
>> +			   val_w);
>> +}
>> +
>> +static void tegra_pcie_enable_legacy_interrupts(struct pcie_port *pp)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
>> +	u32 val;
>> +
>> +	/* Enable legacy interrupt generation */
>> +	val = appl_readl(pcie, APPL_INTR_EN_L0_0);
>> +	val |= APPL_INTR_EN_L0_0_SYS_INTR_EN;
>> +	val |= APPL_INTR_EN_L0_0_INT_INT_EN;
>> +	appl_writel(pcie, val, APPL_INTR_EN_L0_0);
>> +
>> +	val = appl_readl(pcie, APPL_INTR_EN_L1_8_0);
>> +	val |= APPL_INTR_EN_L1_8_INTX_EN;
>> +	val |= APPL_INTR_EN_L1_8_AUTO_BW_INT_EN;
>> +	val |= APPL_INTR_EN_L1_8_BW_MGT_INT_EN;
>> +	if (IS_ENABLED(CONFIG_PCIEAER))
>> +		val |= APPL_INTR_EN_L1_8_AER_INT_EN;
>> +	appl_writel(pcie, val, APPL_INTR_EN_L1_8_0);
>> +}
>> +
>> +static void tegra_pcie_enable_msi_interrupts(struct pcie_port *pp)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
>> +	u32 val;
>> +
>> +	dw_pcie_msi_init(pp);
>> +
>> +	/* Enable MSI interrupt generation */
>> +	val = appl_readl(pcie, APPL_INTR_EN_L0_0);
>> +	val |= APPL_INTR_EN_L0_0_SYS_MSI_INTR_EN;
>> +	val |= APPL_INTR_EN_L0_0_MSI_RCV_INT_EN;
>> +	appl_writel(pcie, val, APPL_INTR_EN_L0_0);
>> +}
>> +
>> +static void tegra_pcie_enable_interrupts(struct pcie_port *pp)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
>> +
>> +	/* Clear interrupt statuses before enabling interrupts */
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L0);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_0_0);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_1);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_2);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_3);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_6);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_7);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_8_0);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_9);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_10);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_11);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_13);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_14);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_15);
>> +	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_17);
>> +
>> +	tegra_pcie_enable_system_interrupts(pp);
>> +	tegra_pcie_enable_legacy_interrupts(pp);
>> +	if (IS_ENABLED(CONFIG_PCI_MSI))
>> +		tegra_pcie_enable_msi_interrupts(pp);
>> +}
>> +
>> +static void config_gen3_gen4_eq_presets(struct tegra_pcie_dw *pcie)
>> +{
>> +	struct dw_pcie *pci = &pcie->pci;
>> +	u32 val, offset, i;
>> +
>> +	/* Program init preset */
>> +	for (i = 0; i < pcie->num_lanes; i++) {
>> +		dw_pcie_read(pci->dbi_base + CAP_SPCIE_CAP_OFF
>> +				 + (i * 2), 2, &val);
>> +		val &= ~CAP_SPCIE_CAP_OFF_DSP_TX_PRESET0_MASK;
>> +		val |= GEN3_GEN4_EQ_PRESET_INIT;
>> +		val &= ~CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_MASK;
>> +		val |= (GEN3_GEN4_EQ_PRESET_INIT <<
>> +			   CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_SHIFT);
>> +		dw_pcie_write(pci->dbi_base + CAP_SPCIE_CAP_OFF
>> +				 + (i * 2), 2, val);
>> +
>> +		offset = dw_pcie_find_ext_capability(pci,
>> +						     PCI_EXT_CAP_ID_PL_16GT) +
>> +				PCI_PL_16GT_LE_CTRL;
>> +		dw_pcie_read(pci->dbi_base + offset + i, 1, &val);
>> +		val &= ~PCI_PL_16GT_LE_CTRL_DSP_TX_PRESET_MASK;
>> +		val |= GEN3_GEN4_EQ_PRESET_INIT;
>> +		val &= ~PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_MASK;
>> +		val |= (GEN3_GEN4_EQ_PRESET_INIT <<
>> +			PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_SHIFT);
>> +		dw_pcie_write(pci->dbi_base + offset + i, 1, val);
>> +	}
>> +
>> +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
>> +	val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
>> +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
>> +
>> +	val = dw_pcie_readl_dbi(pci, GEN3_EQ_CONTROL_OFF);
>> +	val &= ~GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK;
>> +	val |= (0x3ff << GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_SHIFT);
>> +	val &= ~GEN3_EQ_CONTROL_OFF_FB_MODE_MASK;
>> +	dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, val);
>> +
>> +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
>> +	val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
>> +	val |= (0x1 << GEN3_RELATED_OFF_RATE_SHADOW_SEL_SHIFT);
>> +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
>> +
>> +	val = dw_pcie_readl_dbi(pci, GEN3_EQ_CONTROL_OFF);
>> +	val &= ~GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK;
>> +	val |= (0x360 << GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_SHIFT);
>> +	val &= ~GEN3_EQ_CONTROL_OFF_FB_MODE_MASK;
>> +	dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, val);
>> +
>> +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
>> +	val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
>> +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
>> +}
>> +
>> +static int tegra_pcie_dw_host_init(struct pcie_port *pp)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
>> +	u32 val, tmp, offset, speed;
>> +	unsigned int count;
>> +	u16 val_w;
>> +
>> +core_init:
> 
> I think it would be cleaner to include all registers programming
> within a function and we remove this label (and goto) below.
Some background:
As per spec r4.0 v1.0, downstream ports that support 16.0 GT/s must
support Scaled Flow Control (sec 3.4.2) and Tegra194's downstream ports
being 16.0 GT/s capable, enable scaled flow control by having
Data Link Feature (sec 7.7.4) enabled by default. There is one
endpoint (ASMedia USB3.0 controller) that doesn't link up with root port
because of this (i.e. DLF being enabled). The way we are detecting this situation
is to check for partial linkup i.e. one of application logic registers (i.e. from
"appl" region) says link is up but the same is not reflected in configuration space
of root port. Recommendation from our hardware team in this situation is to disable
DLF in root port and try link up with endpoint again.  To achieve this, we put the
core through reset cycle, disable DLF and proceed with configuring all other registers
and check for link up.

Initially in Patch-1, I didn't have goto statement but a recursion with depth-1 (as the
above situation occurs only once). It was reviewed @ http://patchwork.ozlabs.org/patch/1065707/
and Thierry said it would be simpler to use a goto instead of calling the same
function again. So, I modified the code accordingly. Please do let me know if you strongly
feel we should call tegra_pcie_dw_host_init() instead of goto here. I'll change it.

> 
>> +	count = 200;
> 
> It would be easier to read if we could inizialize this value closer
> to where it is actually used. Actually explaining why 200 as value
> was chosen would be appreciated.
Ok.

> 
>> +#if defined(CONFIG_PCIEASPM)
>> +	offset = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_L1SS);
>> +	pcie->cfg_link_cap_l1sub = offset + PCI_L1SS_CAP;
>> +#endif
> 
> Please try to factor this out within a single #ifdef guard.
Ok.

> 
>> +	val = dw_pcie_readl_dbi(pci, PCI_IO_BASE);
>> +	val &= ~(IO_BASE_IO_DECODE | IO_BASE_IO_DECODE_BIT8);
>> +	dw_pcie_writel_dbi(pci, PCI_IO_BASE, val);
>> +
>> +	val = dw_pcie_readl_dbi(pci, PCI_PREF_MEMORY_BASE);
>> +	val |= CFG_PREF_MEM_LIMIT_BASE_MEM_DECODE;
>> +	val |= CFG_PREF_MEM_LIMIT_BASE_MEM_LIMIT_DECODE;
>> +	dw_pcie_writel_dbi(pci, PCI_PREF_MEMORY_BASE, val);
>> +
>> +	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 0);
>> +
>> +	/* Configure FTS */
>> +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL);
>> +	val &= ~(N_FTS_MASK << N_FTS_SHIFT);
>> +	val |= N_FTS_VAL << N_FTS_SHIFT;
>> +	dw_pcie_writel_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL, val);
>> +
>> +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_GEN2_CTRL);
>> +	val &= ~FTS_MASK;
>> +	val |= FTS_VAL;
>> +	dw_pcie_writel_dbi(pci, PORT_LOGIC_GEN2_CTRL, val);
>> +
>> +	/* Enable as 0xFFFF0001 response for CRS */
>> +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT);
>> +	val &= ~(AMBA_ERROR_RESPONSE_CRS_MASK << AMBA_ERROR_RESPONSE_CRS_SHIFT);
>> +	val |= (AMBA_ERROR_RESPONSE_CRS_OKAY_FFFF0001 <<
>> +		AMBA_ERROR_RESPONSE_CRS_SHIFT);
>> +	dw_pcie_writel_dbi(pci, PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT, val);
>> +
>> +	/* Configure Max Speed from DT */
>> +	if (pcie->max_speed && pcie->max_speed != -EINVAL) {
>> +		val = dw_pcie_readl_dbi(pci, pcie->pcie_cap_base +
>> +					PCI_EXP_LNKCAP);
>> +		val &= ~PCI_EXP_LNKCAP_SLS;
>> +		val |= pcie->max_speed;
>> +		dw_pcie_writel_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP,
>> +				   val);
>> +	}
>> +
>> +	/* Configure Max lane width from DT */
>> +	val = dw_pcie_readl_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP);
>> +	val &= ~PCI_EXP_LNKCAP_MLW;
>> +	val |= (pcie->num_lanes << PCI_EXP_LNKSTA_NLW_SHIFT);
>> +	dw_pcie_writel_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP, val);
>> +
>> +	config_gen3_gen4_eq_presets(pcie);
>> +
>> +#if defined(CONFIG_PCIEASPM)
>> +	/* Enable ASPM counters */
>> +	val = EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
>> +	val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
>> +	dw_pcie_writel_dbi(pci, event_cntr_ctrl_offset[pcie->cid], val);
>> +
>> +	/* Program T_cmrt and T_pwr_on values */
>> +	val = dw_pcie_readl_dbi(pci, pcie->cfg_link_cap_l1sub);
>> +	val &= ~(PCI_L1SS_CAP_CM_RESTORE_TIME | PCI_L1SS_CAP_P_PWR_ON_VALUE);
>> +	val |= (pcie->aspm_cmrt << 8);
>> +	val |= (pcie->aspm_pwr_on_t << 19);
>> +	dw_pcie_writel_dbi(pci, pcie->cfg_link_cap_l1sub, val);
>> +
>> +	/* Program L0s and L1 entrance latencies */
>> +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL);
>> +	val &= ~L0S_ENTRANCE_LAT_MASK;
>> +	val |= (pcie->aspm_l0s_enter_lat << L0S_ENTRANCE_LAT_SHIFT);
>> +	val |= ENTER_ASPM;
>> +	dw_pcie_writel_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL, val);
>> +#endif
> 
> See above.
Ok.

> 
>> +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
>> +	val &= ~GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL;
>> +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
>> +
>> +	if (pcie->update_fc_fixup) {
>> +		val = dw_pcie_readl_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF);
>> +		val |= 0x1 << CFG_TIMER_CTRL_ACK_NAK_SHIFT;
>> +		dw_pcie_writel_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF, val);
>> +	}
>> +
>> +	dw_pcie_setup_rc(pp);
>> +
>> +	clk_set_rate(pcie->core_clk, GEN4_CORE_CLK_FREQ);
>> +
>> +	/* Assert RST */
>> +	val = appl_readl(pcie, APPL_PINMUX);
>> +	val &= ~APPL_PINMUX_PEX_RST;
>> +	appl_writel(pcie, val, APPL_PINMUX);
>> +
>> +	usleep_range(100, 200);
>> +
>> +	/* Enable LTSSM */
>> +	val = appl_readl(pcie, APPL_CTRL);
>> +	val |= APPL_CTRL_LTSSM_EN;
>> +	appl_writel(pcie, val, APPL_CTRL);
>> +
>> +	/* De-assert RST */
>> +	val = appl_readl(pcie, APPL_PINMUX);
>> +	val |= APPL_PINMUX_PEX_RST;
>> +	appl_writel(pcie, val, APPL_PINMUX);
>> +
>> +	msleep(100);
>> +
>> +	val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
>> +	while (!(val_w & PCI_EXP_LNKSTA_DLLLA)) {
>> +		if (count) {
>> +			dev_dbg(pci->dev, "Waiting for link up\n");
>> +			usleep_range(1000, 2000);
>> +			val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
>> +						  PCI_EXP_LNKSTA);
>> +			count--;
>> +			continue;
>> +		}
>> +
>> +		val = appl_readl(pcie, APPL_DEBUG);
>> +		val &= APPL_DEBUG_LTSSM_STATE_MASK;
>> +		val >>= APPL_DEBUG_LTSSM_STATE_SHIFT;
>> +		tmp = appl_readl(pcie, APPL_LINK_STATUS);
>> +		tmp &= APPL_LINK_STATUS_RDLH_LINK_UP;
>> +		if (!(val == 0x11 && !tmp)) {
>> +			dev_info(pci->dev, "Link is down\n");
>> +			return 0;
>> +		}
>> +
>> +		dev_info(pci->dev, "Link is down in DLL");
>> +		dev_info(pci->dev, "Trying again with DLFE disabled\n");
>> +		/* Disable LTSSM */
>> +		val = appl_readl(pcie, APPL_CTRL);
>> +		val &= ~APPL_CTRL_LTSSM_EN;
>> +		appl_writel(pcie, val, APPL_CTRL);
>> +
>> +		reset_control_assert(pcie->core_rst);
>> +		reset_control_deassert(pcie->core_rst);
>> +
>> +		offset = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_DLF);
>> +		val = dw_pcie_readl_dbi(pci, offset + PCI_DLF_CAP);
>> +		val &= ~PCI_DLF_EXCHANGE_ENABLE;
>> +		dw_pcie_writel_dbi(pci, offset, val);
>> +
>> +		/* Retry now with DLF Exchange disabled */
>> +		goto core_init;
> 
> This goto upwards honestly is a bit horrible. Use some functions
> to make the code more readable.
Updated my comments above.

> 
>> +	}
>> +	dev_dbg(pci->dev, "Link is up\n");
>> +
>> +	speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
>> +		PCI_EXP_LNKSTA_CLS;
>> +	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
>> +
>> +	tegra_pcie_enable_interrupts(pp);
>> +
>> +	return 0;
>> +}
>> +
>> +static int tegra_pcie_dw_link_up(struct dw_pcie *pci)
>> +{
>> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
>> +	u32 val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
>> +
>> +	return !!(val & PCI_EXP_LNKSTA_DLLLA);
> 
> It looks like this can be common code reusable by other DWC drivers ?
> 
> Not mandatory, just a hint.
Well, each DesignWare core based implementation has a different way to find out
if the link is up and hence this hook is provided by DWC framework to let host controller
drivers implement their implementation specific link up check. In Tegra194, we are just
relying on spec defined configuration space register for link up.

> 
>> +}
>> +
>> +static void tegra_pcie_set_msi_vec_num(struct pcie_port *pp)
>> +{
>> +	pp->num_vectors = MAX_MSI_IRQS;
>> +}
>> +
>> +static const struct dw_pcie_ops tegra_dw_pcie_ops = {
>> +	.link_up = tegra_pcie_dw_link_up,
>> +};
>> +
>> +static struct dw_pcie_host_ops tegra_pcie_dw_host_ops = {
>> +	.rd_own_conf = tegra_pcie_dw_rd_own_conf,
>> +	.wr_own_conf = tegra_pcie_dw_wr_own_conf,
>> +	.host_init = tegra_pcie_dw_host_init,
>> +	.set_num_vectors = tegra_pcie_set_msi_vec_num,
>> +};
>> +
>> +static void tegra_pcie_disable_phy(struct tegra_pcie_dw *pcie)
>> +{
>> +	unsigned int phy_count = pcie->phy_count;
>> +
>> +	while (phy_count--) {
>> +		phy_power_off(pcie->phys[phy_count]);
>> +		phy_exit(pcie->phys[phy_count]);
>> +	}
>> +}
>> +
>> +static int tegra_pcie_enable_phy(struct tegra_pcie_dw *pcie)
>> +{
>> +	unsigned int i;
>> +	int ret;
>> +
>> +	for (i = 0; i < pcie->phy_count; i++) {
>> +		ret = phy_init(pcie->phys[i]);
>> +		if (ret < 0)
>> +			goto phy_power_off;
>> +
>> +		ret = phy_power_on(pcie->phys[i]);
>> +		if (ret < 0)
>> +			goto phy_exit;
>> +	}
>> +
>> +	return 0;
>> +
>> +phy_power_off:
>> +	while (i--) {
>> +		phy_power_off(pcie->phys[i]);
>> +phy_exit:
>> +		phy_exit(pcie->phys[i]);
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static int tegra_pcie_dw_parse_dt(struct tegra_pcie_dw *pcie)
>> +{
>> +	struct device_node *np = pcie->dev->of_node;
>> +	int ret;
>> +
>> +	ret = of_property_read_u32(np, "nvidia,aspm-cmrt-us", &pcie->aspm_cmrt);
>> +	if (ret < 0) {
>> +		dev_info(pcie->dev, "Failed to read ASPM T_cmrt: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	ret = of_property_read_u32(np, "nvidia,aspm-pwr-on-t-us",
>> +				   &pcie->aspm_pwr_on_t);
>> +	if (ret < 0)
>> +		dev_info(pcie->dev, "Failed to read ASPM Power On time: %d\n",
>> +			 ret);
>> +
>> +	ret = of_property_read_u32(np, "nvidia,aspm-l0s-entrance-latency-us",
>> +				   &pcie->aspm_l0s_enter_lat);
>> +	if (ret < 0)
>> +		dev_info(pcie->dev,
>> +			 "Failed to read ASPM L0s Entrance latency: %d\n", ret);
>> +
>> +	ret = of_property_read_u32(np, "num-lanes", &pcie->num_lanes);
>> +	if (ret < 0) {
>> +		dev_err(pcie->dev, "Failed to read num-lanes: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	pcie->max_speed = of_pci_get_max_link_speed(np);
>> +
>> +	ret = of_property_read_u32_index(np, "nvidia,bpmp", 1, &pcie->cid);
>> +	if (ret) {
>> +		dev_err(pcie->dev, "Failed to read Controller-ID: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	pcie->phy_count = of_property_count_strings(np, "phy-names");
>> +	if (pcie->phy_count < 0) {
>> +		dev_err(pcie->dev, "Failed to find PHY entries: %d\n",
>> +			pcie->phy_count);
>> +		return pcie->phy_count;
>> +	}
>> +
>> +	if (of_property_read_bool(np, "nvidia,update-fc-fixup"))
>> +		pcie->update_fc_fixup = true;
>> +
>> +	pcie->supports_clkreq =
>> +		of_property_read_bool(pcie->dev->of_node, "supports-clkreq");
>> +
>> +	pcie->enable_cdm_check =
>> +		of_property_read_bool(np, "snps,enable-cdm-check");
>> +
>> +	return 0;
>> +}
>> +
>> +static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
>> +					  bool enable)
>> +{
>> +	struct mrq_uphy_response resp;
>> +	struct tegra_bpmp_message msg;
>> +	struct mrq_uphy_request req;
>> +	int err;
>> +
>> +	if (pcie->cid == 5)
>> +		return 0;
> 
> What's wrong with cid == 5 ? Explain please.
Controller with ID=5 doesn't need any programming to enable it which is
done here through calling firmware API.

> 
>> +	memset(&req, 0, sizeof(req));
>> +	memset(&resp, 0, sizeof(resp));
>> +
>> +	req.cmd = CMD_UPHY_PCIE_CONTROLLER_STATE;
>> +	req.controller_state.pcie_controller = pcie->cid;
>> +	req.controller_state.enable = enable;
>> +
>> +	memset(&msg, 0, sizeof(msg));
>> +	msg.mrq = MRQ_UPHY;
>> +	msg.tx.data = &req;
>> +	msg.tx.size = sizeof(req);
>> +	msg.rx.data = &resp;
>> +	msg.rx.size = sizeof(resp);
>> +
>> +	if (irqs_disabled())
> 
> Can you explain to me what this check is meant to achieve please ?
Firmware interface provides different APIs to be called when there are no
interrupts enabled in the system (noirq context) and otherwise hence
checking that situation here and calling appropriate API.

> 
>> +		err = tegra_bpmp_transfer_atomic(pcie->bpmp, &msg);
>> +	else
>> +		err = tegra_bpmp_transfer(pcie->bpmp, &msg);
>> +
>> +	return err;
>> +}
>> +
>> +static void tegra_pcie_downstream_dev_to_D0(struct tegra_pcie_dw *pcie)
>> +{
>> +	struct pcie_port *pp = &pcie->pci.pp;
>> +	struct pci_dev *pdev;
>> +	struct pci_bus *child;
>> +
>> +	list_for_each_entry(child, &pp->root_bus->children, node) {
>> +		/* Bring downstream devices to D0 if they are not already in */
>> +		if (child->parent == pp->root_bus)
>> +			break;
>> +	}
>> +	list_for_each_entry(pdev, &child->devices, bus_list) {
>> +		if (PCI_SLOT(pdev->devfn) == 0) {
>> +			if (pci_set_power_state(pdev, PCI_D0))
>> +				dev_err(pcie->dev,
>> +					"Failed to transition %s to D0 state\n",
>> +					dev_name(&pdev->dev));
>> +		}
>> +	}
>> +}
>> +
>> +static int tegra_pcie_config_controller(struct tegra_pcie_dw *pcie,
>> +					bool en_hw_hot_rst)
>> +{
>> +	int ret;
>> +	u32 val;
>> +
>> +	ret = tegra_pcie_bpmp_set_ctrl_state(pcie, true);
>> +	if (ret) {
>> +		dev_err(pcie->dev,
>> +			"Failed to enable controller %u: %d\n", pcie->cid, ret);
>> +		return ret;
>> +	}
>> +
>> +	ret = regulator_enable(pcie->pex_ctl_supply);
>> +	if (ret < 0) {
>> +		dev_err(pcie->dev, "Failed to enable regulator: %d\n", ret);
>> +		goto fail_reg_en;
>> +	}
>> +
>> +	ret = clk_prepare_enable(pcie->core_clk);
>> +	if (ret) {
>> +		dev_err(pcie->dev, "Failed to enable core clock: %d\n", ret);
>> +		goto fail_core_clk;
>> +	}
>> +
>> +	ret = reset_control_deassert(pcie->core_apb_rst);
>> +	if (ret) {
>> +		dev_err(pcie->dev, "Failed to deassert core APB reset: %d\n",
>> +			ret);
>> +		goto fail_core_apb_rst;
>> +	}
>> +
>> +	if (en_hw_hot_rst) {
>> +		/* Enable HW_HOT_RST mode */
>> +		val = appl_readl(pcie, APPL_CTRL);
>> +		val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
>> +			 APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
>> +		val |= APPL_CTRL_HW_HOT_RST_EN;
>> +		appl_writel(pcie, val, APPL_CTRL);
>> +	}
>> +
>> +	ret = tegra_pcie_enable_phy(pcie);
>> +	if (ret) {
>> +		dev_err(pcie->dev, "Failed to enable PHY: %d\n", ret);
>> +		goto fail_phy;
>> +	}
>> +
>> +	/* Update CFG base address */
>> +	appl_writel(pcie, pcie->dbi_res->start & APPL_CFG_BASE_ADDR_MASK,
>> +		    APPL_CFG_BASE_ADDR);
>> +
>> +	/* Configure this core for RP mode operation */
>> +	appl_writel(pcie, APPL_DM_TYPE_RP, APPL_DM_TYPE);
>> +
>> +	appl_writel(pcie, 0x0, APPL_CFG_SLCG_OVERRIDE);
>> +
>> +	val = appl_readl(pcie, APPL_CTRL);
>> +	appl_writel(pcie, val | APPL_CTRL_SYS_PRE_DET_STATE, APPL_CTRL);
>> +
>> +	val = appl_readl(pcie, APPL_CFG_MISC);
>> +	val |= (APPL_CFG_MISC_ARCACHE_VAL << APPL_CFG_MISC_ARCACHE_SHIFT);
>> +	appl_writel(pcie, val, APPL_CFG_MISC);
>> +
>> +	if (!pcie->supports_clkreq) {
>> +		val = appl_readl(pcie, APPL_PINMUX);
>> +		val |= APPL_PINMUX_CLKREQ_OUT_OVRD_EN;
>> +		val |= APPL_PINMUX_CLKREQ_OUT_OVRD;
>> +		appl_writel(pcie, val, APPL_PINMUX);
>> +	}
>> +
>> +	/* Update iATU_DMA base address */
>> +	appl_writel(pcie,
>> +		    pcie->atu_dma_res->start & APPL_CFG_IATU_DMA_BASE_ADDR_MASK,
>> +		    APPL_CFG_IATU_DMA_BASE_ADDR);
>> +
>> +	reset_control_deassert(pcie->core_rst);
>> +
>> +	pcie->pcie_cap_base = dw_pcie_find_capability(&pcie->pci,
>> +						      PCI_CAP_ID_EXP);
>> +
>> +#if defined(CONFIG_PCIEASPM)
>> +	/* Disable ASPM-L1SS advertisement as there is no CLKREQ routing */
>> +	if (!pcie->supports_clkreq) {
>> +		disable_aspm_l11(pcie);
>> +		disable_aspm_l12(pcie);
>> +	}
>> +#endif
>> +	return ret;
>> +
>> +fail_phy:
>> +	reset_control_assert(pcie->core_apb_rst);
>> +fail_core_apb_rst:
>> +	clk_disable_unprepare(pcie->core_clk);
>> +fail_core_clk:
>> +	regulator_disable(pcie->pex_ctl_supply);
>> +fail_reg_en:
>> +	tegra_pcie_bpmp_set_ctrl_state(pcie, false);
>> +
>> +	return ret;
>> +}
>> +
>> +static int __deinit_controller(struct tegra_pcie_dw *pcie)
>> +{
>> +	int ret;
>> +
>> +	ret = reset_control_assert(pcie->core_rst);
>> +	if (ret) {
>> +		dev_err(pcie->dev, "Failed to assert \"core\" reset: %d\n",
>> +			ret);
>> +		return ret;
>> +	}
>> +	tegra_pcie_disable_phy(pcie);
>> +	ret = reset_control_assert(pcie->core_apb_rst);
>> +	if (ret) {
>> +		dev_err(pcie->dev, "Failed to assert APB reset: %d\n", ret);
>> +		return ret;
>> +	}
>> +	clk_disable_unprepare(pcie->core_clk);
>> +	ret = regulator_disable(pcie->pex_ctl_supply);
>> +	if (ret) {
>> +		dev_err(pcie->dev, "Failed to disable regulator: %d\n", ret);
>> +		return ret;
>> +	}
>> +	ret = tegra_pcie_bpmp_set_ctrl_state(pcie, false);
>> +	if (ret) {
>> +		dev_err(pcie->dev, "Failed to disable controller %d: %d\n",
>> +			pcie->cid, ret);
>> +		return ret;
>> +	}
>> +	return ret;
>> +}
>> +
>> +static int tegra_pcie_init_controller(struct tegra_pcie_dw *pcie)
>> +{
>> +	struct dw_pcie *pci = &pcie->pci;
>> +	struct pcie_port *pp = &pci->pp;
>> +	int ret;
>> +
>> +	ret = tegra_pcie_config_controller(pcie, false);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	pp->root_bus_nr = -1;
>> +	pp->ops = &tegra_pcie_dw_host_ops;
>> +
>> +	ret = dw_pcie_host_init(pp);
>> +	if (ret < 0) {
>> +		dev_err(pcie->dev, "Failed to add PCIe port: %d\n", ret);
>> +		goto fail_host_init;
>> +	}
>> +
>> +	return 0;
>> +
>> +fail_host_init:
>> +	return __deinit_controller(pcie);
>> +}
>> +
>> +static int tegra_pcie_try_link_l2(struct tegra_pcie_dw *pcie)
>> +{
>> +	u32 val;
>> +
>> +	if (!tegra_pcie_dw_link_up(&pcie->pci))
>> +		return 0;
>> +
>> +	val = appl_readl(pcie, APPL_RADM_STATUS);
>> +	val |= APPL_PM_XMT_TURNOFF_STATE;
>> +	appl_writel(pcie, val, APPL_RADM_STATUS);
>> +
>> +	return readl_poll_timeout_atomic(pcie->appl_base + APPL_DEBUG, val,
>> +				 val & APPL_DEBUG_PM_LINKST_IN_L2_LAT,
>> +				 1, PME_ACK_TIMEOUT);
>> +}
>> +
>> +static void tegra_pcie_dw_pme_turnoff(struct tegra_pcie_dw *pcie)
>> +{
>> +	u32 data;
>> +	int err;
>> +
>> +	if (!tegra_pcie_dw_link_up(&pcie->pci)) {
>> +		dev_dbg(pcie->dev, "PCIe link is not up...!\n");
>> +		return;
>> +	}
>> +
>> +	if (tegra_pcie_try_link_l2(pcie)) {
>> +		dev_info(pcie->dev, "Link didn't transition to L2 state\n");
>> +		/*
>> +		 * TX lane clock freq will reset to Gen1 only if link is in L2
>> +		 * or detect state.
>> +		 * So apply pex_rst to end point to force RP to go into detect
>> +		 * state
>> +		 */
>> +		data = appl_readl(pcie, APPL_PINMUX);
>> +		data &= ~APPL_PINMUX_PEX_RST;
>> +		appl_writel(pcie, data, APPL_PINMUX);
>> +
>> +		err = readl_poll_timeout_atomic(pcie->appl_base + APPL_DEBUG,
>> +						data,
>> +						((data &
>> +						APPL_DEBUG_LTSSM_STATE_MASK) >>
>> +						APPL_DEBUG_LTSSM_STATE_SHIFT) ==
>> +						LTSSM_STATE_PRE_DETECT,
>> +						1, LTSSM_TIMEOUT);
>> +		if (err) {
>> +			dev_info(pcie->dev, "Link didn't go to detect state\n");
>> +		} else {
>> +			/* Disable LTSSM after link is in detect state */
>> +			data = appl_readl(pcie, APPL_CTRL);
>> +			data &= ~APPL_CTRL_LTSSM_EN;
>> +			appl_writel(pcie, data, APPL_CTRL);
>> +		}
>> +	}
>> +	/*
>> +	 * DBI registers may not be accessible after this as PLL-E would be
>> +	 * down depending on how CLKREQ is pulled by end point
>> +	 */
>> +	data = appl_readl(pcie, APPL_PINMUX);
>> +	data |= (APPL_PINMUX_CLKREQ_OVERRIDE_EN | APPL_PINMUX_CLKREQ_OVERRIDE);
>> +	/* Cut REFCLK to slot */
>> +	data |= APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE_EN;
>> +	data &= ~APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE;
>> +	appl_writel(pcie, data, APPL_PINMUX);
>> +}
>> +
>> +static int tegra_pcie_deinit_controller(struct tegra_pcie_dw *pcie)
>> +{
>> +	/*
>> +	 * link doesn't go into L2 state with some of the endpoints with Tegra
>> +	 * if they are not in D0 state. So, need to make sure that immediate
>> +	 * downstream devices are in D0 state before sending PME_TurnOff to put
>> +	 * link into L2 state
>> +	 */
>> +	tegra_pcie_downstream_dev_to_D0(pcie);
>> +	dw_pcie_host_deinit(&pcie->pci.pp);
>> +	tegra_pcie_dw_pme_turnoff(pcie);
>> +	return __deinit_controller(pcie);
>> +}
>> +
>> +static int tegra_pcie_config_rp(struct tegra_pcie_dw *pcie)
>> +{
>> +	struct pcie_port *pp = &pcie->pci.pp;
>> +	struct device *dev = pcie->dev;
>> +	char *name;
>> +	int ret;
>> +
>> +	if (IS_ENABLED(CONFIG_PCI_MSI)) {
>> +		pp->msi_irq = of_irq_get_byname(dev->of_node, "msi");
>> +		if (!pp->msi_irq) {
>> +			dev_err(dev, "Failed to get MSI interrupt\n");
>> +			return -ENODEV;
>> +		}
>> +	}
>> +
>> +	pm_runtime_enable(dev);
>> +	ret = pm_runtime_get_sync(dev);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to get runtime sync for PCIe dev: %d\n",
>> +			ret);
>> +		pm_runtime_disable(dev);
>> +		return ret;
>> +	}
>> +
>> +	tegra_pcie_init_controller(pcie);
>> +
>> +	pcie->link_state = tegra_pcie_dw_link_up(&pcie->pci);
>> +
>> +	if (!pcie->link_state) {
>> +		ret = -ENOMEDIUM;
>> +		goto fail_host_init;
>> +	}
>> +
>> +	name = devm_kasprintf(dev, GFP_KERNEL, "%pOFP", dev->of_node);
>> +	if (!name) {
>> +		ret = -ENOMEM;
>> +		goto fail_host_init;
>> +	}
>> +
>> +	pcie->debugfs = debugfs_create_dir(name, NULL);
>> +	if (!pcie->debugfs)
>> +		dev_err(dev, "Failed to create debugfs\n");
>> +	else
>> +		init_debugfs(pcie);
>> +
>> +	return ret;
>> +
>> +fail_host_init:
>> +	tegra_pcie_deinit_controller(pcie);
>> +	pm_runtime_put_sync(dev);
>> +	pm_runtime_disable(dev);
>> +	return ret;
>> +}
>> +
>> +static const struct tegra_pcie_soc tegra_pcie_rc_of_data = {
>> +	.mode = DW_PCIE_RC_TYPE,
>> +};
>> +
>> +static const struct of_device_id tegra_pcie_dw_of_match[] = {
>> +	{
>> +		.compatible = "nvidia,tegra194-pcie",
>> +		.data = &tegra_pcie_rc_of_data,
>> +	},
>> +	{},
>> +};
>> +MODULE_DEVICE_TABLE(of, tegra_pcie_dw_of_match);
>> +
>> +static int tegra_pcie_dw_probe(struct platform_device *pdev)
>> +{
>> +	const struct tegra_pcie_soc *data;
>> +	struct device *dev = &pdev->dev;
>> +	struct resource *atu_dma_res;
>> +	struct tegra_pcie_dw *pcie;
>> +	struct resource *dbi_res;
>> +	struct pcie_port *pp;
>> +	struct dw_pcie *pci;
>> +	struct phy **phys;
>> +	char *name;
>> +	int ret;
>> +	u32 i;
>> +
>> +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
>> +	if (!pcie)
>> +		return -ENOMEM;
>> +
>> +	pci = &pcie->pci;
>> +	pci->dev = &pdev->dev;
>> +	pci->ops = &tegra_dw_pcie_ops;
>> +	pp = &pci->pp;
>> +	pcie->dev = &pdev->dev;
>> +
>> +	data = (struct tegra_pcie_soc *)of_device_get_match_data(dev);
>> +	if (!data)
>> +		return -EINVAL;
>> +	pcie->mode = (enum dw_pcie_device_mode)data->mode;
>> +
>> +	ret = tegra_pcie_dw_parse_dt(pcie);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to parse device tree: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	pcie->pex_ctl_supply = devm_regulator_get(dev, "vddio-pex-ctl");
>> +	if (IS_ERR(pcie->pex_ctl_supply)) {
>> +		dev_err(dev, "Failed to get regulator: %ld\n",
>> +			PTR_ERR(pcie->pex_ctl_supply));
>> +		return PTR_ERR(pcie->pex_ctl_supply);
>> +	}
>> +
>> +	pcie->core_clk = devm_clk_get(dev, "core");
>> +	if (IS_ERR(pcie->core_clk)) {
>> +		dev_err(dev, "Failed to get core clock: %ld\n",
>> +			PTR_ERR(pcie->core_clk));
>> +		return PTR_ERR(pcie->core_clk);
>> +	}
>> +
>> +	pcie->appl_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>> +						      "appl");
>> +	if (!pcie->appl_res) {
>> +		dev_err(dev, "Failed to find \"appl\" region\n");
>> +		return PTR_ERR(pcie->appl_res);
>> +	}
>> +	pcie->appl_base = devm_ioremap_resource(dev, pcie->appl_res);
>> +	if (IS_ERR(pcie->appl_base))
>> +		return PTR_ERR(pcie->appl_base);
>> +
>> +	pcie->core_apb_rst = devm_reset_control_get(dev, "apb");
>> +	if (IS_ERR(pcie->core_apb_rst)) {
>> +		dev_err(dev, "Failed to get APB reset: %ld\n",
>> +			PTR_ERR(pcie->core_apb_rst));
>> +		return PTR_ERR(pcie->core_apb_rst);
>> +	}
>> +
>> +	phys = devm_kcalloc(dev, pcie->phy_count, sizeof(*phys), GFP_KERNEL);
>> +	if (!phys)
>> +		return PTR_ERR(phys);
>> +
>> +	for (i = 0; i < pcie->phy_count; i++) {
>> +		name = kasprintf(GFP_KERNEL, "p2u-%u", i);
>> +		if (!name) {
>> +			dev_err(dev, "Failed to create P2U string\n");
>> +			return -ENOMEM;
>> +		}
>> +		phys[i] = devm_phy_get(dev, name);
>> +		kfree(name);
>> +		if (IS_ERR(phys[i])) {
>> +			ret = PTR_ERR(phys[i]);
>> +			dev_err(dev, "Failed to get PHY: %d\n", ret);
>> +			return ret;
>> +		}
>> +	}
>> +
>> +	pcie->phys = phys;
>> +
>> +	dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
>> +	if (!dbi_res) {
>> +		dev_err(dev, "Failed to find \"dbi\" region\n");
>> +		return PTR_ERR(dbi_res);
>> +	}
>> +	pcie->dbi_res = dbi_res;
>> +
>> +	pci->dbi_base = devm_ioremap_resource(dev, dbi_res);
>> +	if (IS_ERR(pci->dbi_base))
>> +		return PTR_ERR(pci->dbi_base);
>> +
>> +	/* Tegra HW locates DBI2 at a fixed offset from DBI */
>> +	pci->dbi_base2 = pci->dbi_base + 0x1000;
>> +
>> +	atu_dma_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>> +						   "atu_dma");
>> +	if (!atu_dma_res) {
>> +		dev_err(dev, "Failed to find \"atu_dma\" region\n");
>> +		return PTR_ERR(atu_dma_res);
>> +	}
>> +	pcie->atu_dma_res = atu_dma_res;
>> +	pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);
>> +	if (IS_ERR(pci->atu_base))
>> +		return PTR_ERR(pci->atu_base);
>> +
>> +	pcie->core_rst = devm_reset_control_get(dev, "core");
>> +	if (IS_ERR(pcie->core_rst)) {
>> +		dev_err(dev, "Failed to get core reset: %ld\n",
>> +			PTR_ERR(pcie->core_rst));
>> +		return PTR_ERR(pcie->core_rst);
>> +	}
>> +
>> +	pp->irq = platform_get_irq_byname(pdev, "intr");
>> +	if (!pp->irq) {
>> +		dev_err(dev, "Failed to get \"intr\" interrupt\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	ret = devm_request_irq(dev, pp->irq, tegra_pcie_irq_handler,
>> +			       IRQF_SHARED, "tegra-pcie-intr", pcie);
>> +	if (ret) {
>> +		dev_err(dev, "Failed to request IRQ %d: %d\n", pp->irq, ret);
>> +		return ret;
>> +	}
>> +
>> +	pcie->bpmp = tegra_bpmp_get(dev);
>> +	if (IS_ERR(pcie->bpmp))
>> +		return PTR_ERR(pcie->bpmp);
>> +
>> +	platform_set_drvdata(pdev, pcie);
>> +
>> +	if (pcie->mode == DW_PCIE_RC_TYPE) {
>> +		ret = tegra_pcie_config_rp(pcie);
>> +		if (ret && ret != -ENOMEDIUM)
>> +			goto fail;
>> +		else
>> +			return 0;
> 
> So if the link is not up we still go ahead and make probe
> succeed. What for ?
We may need root port to be available to support hot-plugging of endpoint
devices, so, we don't fail the probe.

> 
>> +	}
>> +
>> +fail:
>> +	tegra_bpmp_put(pcie->bpmp);
>> +	return ret;
>> +}
>> +
>> +static int tegra_pcie_dw_remove(struct platform_device *pdev)
>> +{
>> +	struct tegra_pcie_dw *pcie = platform_get_drvdata(pdev);
>> +
>> +	if (pcie->mode != DW_PCIE_RC_TYPE)
>> +		return 0;
>> +
>> +	if (!pcie->link_state)
>> +		return 0;
>> +
>> +	debugfs_remove_recursive(pcie->debugfs);
>> +	tegra_pcie_deinit_controller(pcie);
>> +	pm_runtime_put_sync(pcie->dev);
>> +	pm_runtime_disable(pcie->dev);
>> +	tegra_bpmp_put(pcie->bpmp);
>> +
>> +	return 0;
>> +}
>> +
>> +static int tegra_pcie_dw_suspend_late(struct device *dev)
>> +{
>> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
>> +	u32 val;
>> +
>> +	if (!pcie->link_state)
>> +		return 0;
>> +
>> +	/* Enable HW_HOT_RST mode */
>> +	val = appl_readl(pcie, APPL_CTRL);
>> +	val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
>> +		 APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
>> +	val |= APPL_CTRL_HW_HOT_RST_EN;
>> +	appl_writel(pcie, val, APPL_CTRL);
>> +
>> +	return 0;
>> +}
>> +
>> +static int tegra_pcie_dw_suspend_noirq(struct device *dev)
>> +{
>> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
>> +
>> +	if (!pcie->link_state)
>> +		return 0;
>> +
>> +	/* Save MSI interrupt vector */
>> +	pcie->msi_ctrl_int = dw_pcie_readl_dbi(&pcie->pci,
>> +					       PORT_LOGIC_MSI_CTRL_INT_0_EN);
>> +	tegra_pcie_downstream_dev_to_D0(pcie);
> 
> I think this requires some comments. AFAIU this is allowed by
> the PCI specs (PCI Express Base 4.0 r1.0 September 29-2017,
> 5.2 Link State Power Management). However, I would like to
> understand how this plays with the D state the devices are left
> in upon system suspend.
> 
> "As the following example illustrates, it is also possible to remove
> power without first placing all Functions into D3Hot".
> 
> I assume that's what happens on this platform to allow L2 entry but
> again, this needs clarification.
Yes. It is true that in the case of Tegra194, it brings devices back to D0
before putting link to L2 state.

> 
> Lorenzo
> 
>> +	tegra_pcie_dw_pme_turnoff(pcie);
>> +	return __deinit_controller(pcie);
>> +}
>> +
>> +static int tegra_pcie_dw_resume_noirq(struct device *dev)
>> +{
>> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
>> +	int ret;
>> +
>> +	if (!pcie->link_state)
>> +		return 0;
>> +
>> +	ret = tegra_pcie_config_controller(pcie, true);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	ret = tegra_pcie_dw_host_init(&pcie->pci.pp);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to init host: %d\n", ret);
>> +		goto fail_host_init;
>> +	}
>> +
>> +	/* Restore MSI interrupt vector */
>> +	dw_pcie_writel_dbi(&pcie->pci, PORT_LOGIC_MSI_CTRL_INT_0_EN,
>> +			   pcie->msi_ctrl_int);
>> +
>> +	return 0;
>> +fail_host_init:
>> +	return __deinit_controller(pcie);
>> +}
>> +
>> +static int tegra_pcie_dw_resume_early(struct device *dev)
>> +{
>> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
>> +	u32 val;
>> +
>> +	if (!pcie->link_state)
>> +		return 0;
>> +
>> +	/* Disable HW_HOT_RST mode */
>> +	val = appl_readl(pcie, APPL_CTRL);
>> +	val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
>> +		 APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
>> +	val |= APPL_CTRL_HW_HOT_RST_MODE_IMDT_RST <<
>> +	       APPL_CTRL_HW_HOT_RST_MODE_SHIFT;
>> +	val &= ~APPL_CTRL_HW_HOT_RST_EN;
>> +	appl_writel(pcie, val, APPL_CTRL);
>> +
>> +	return 0;
>> +}
>> +
>> +static void tegra_pcie_dw_shutdown(struct platform_device *pdev)
>> +{
>> +	struct tegra_pcie_dw *pcie = platform_get_drvdata(pdev);
>> +
>> +	if (pcie->mode != DW_PCIE_RC_TYPE)
>> +		return;
>> +
>> +	if (!pcie->link_state)
>> +		return;
>> +
>> +	debugfs_remove_recursive(pcie->debugfs);
>> +	tegra_pcie_downstream_dev_to_D0(pcie);
>> +
>> +	disable_irq(pcie->pci.pp.irq);
>> +	if (IS_ENABLED(CONFIG_PCI_MSI))
>> +		disable_irq(pcie->pci.pp.msi_irq);
>> +
>> +	tegra_pcie_dw_pme_turnoff(pcie);
>> +	__deinit_controller(pcie);
>> +}
>> +
>> +static const struct dev_pm_ops tegra_pcie_dw_pm_ops = {
>> +	.suspend_late = tegra_pcie_dw_suspend_late,
>> +	.suspend_noirq = tegra_pcie_dw_suspend_noirq,
>> +	.resume_noirq = tegra_pcie_dw_resume_noirq,
>> +	.resume_early = tegra_pcie_dw_resume_early,
>> +};
>> +
>> +static struct platform_driver tegra_pcie_dw_driver = {
>> +	.probe = tegra_pcie_dw_probe,
>> +	.remove = tegra_pcie_dw_remove,
>> +	.shutdown = tegra_pcie_dw_shutdown,
>> +	.driver = {
>> +		.name	= "tegra194-pcie",
>> +		.pm = &tegra_pcie_dw_pm_ops,
>> +		.of_match_table = tegra_pcie_dw_of_match,
>> +	},
>> +};
>> +module_platform_driver(tegra_pcie_dw_driver);
>> +
>> +MODULE_AUTHOR("Vidya Sagar <vidyas@nvidia.com>");
>> +MODULE_DESCRIPTION("NVIDIA PCIe host controller driver");
>> +MODULE_LICENSE("GPL v2");
>> -- 
>> 2.17.1
>>

On Fri, Jul 12, 2019 at 09:02:49PM +0530, Vidya Sagar wrote:

[...]

> > > +static irqreturn_t tegra_pcie_irq_handler(int irq, void *arg)
> > > +{
> > > +	struct tegra_pcie_dw *pcie = arg;
> > > +
> > > +	if (pcie->mode == DW_PCIE_RC_TYPE)
> > > +		return tegra_pcie_rp_irq_handler(pcie);
> > 
> > What's the point of registering the handler if mode != DW_PCIE_RC_TYPE ?
> Currently this driver supports only root port mode but we have a plan
> to add support for endpoint mode (as Tegra194 as dual mode
> controllers) also in future and when that happens, we'll have a
> corresponding tegra_pcie_ep_irq_handler() to take care of ep specific
> interrupts.

Sure, that's why you should add tegra_pcie_dw->mode when it is needed,
not in this patch.

[...]

> > > +static int tegra_pcie_dw_host_init(struct pcie_port *pp)
> > > +{
> > > +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> > > +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> > > +	u32 val, tmp, offset, speed;
> > > +	unsigned int count;
> > > +	u16 val_w;
> > > +
> > > +core_init:
> > 
> > I think it would be cleaner to include all registers programming
> > within a function and we remove this label (and goto) below.
> Some background: As per spec r4.0 v1.0, downstream ports that support
> 16.0 GT/s must support Scaled Flow Control (sec 3.4.2) and Tegra194's
> downstream ports being 16.0 GT/s capable, enable scaled flow control
> by having Data Link Feature (sec 7.7.4) enabled by default. There is
> one endpoint (ASMedia USB3.0 controller) that doesn't link up with
> root port because of this (i.e. DLF being enabled). The way we are
> detecting this situation is to check for partial linkup i.e. one of
> application logic registers (i.e. from "appl" region) says link is up
> but the same is not reflected in configuration space of root port.
> Recommendation from our hardware team in this situation is to disable
> DLF in root port and try link up with endpoint again.  To achieve
> this, we put the core through reset cycle, disable DLF and proceed
> with configuring all other registers and check for link up.
> 
> Initially in Patch-1, I didn't have goto statement but a recursion
> with depth-1 (as the above situation occurs only once). It was
> reviewed @ http://patchwork.ozlabs.org/patch/1065707/ and Thierry said
> it would be simpler to use a goto instead of calling the same function
> again. So, I modified the code accordingly. Please do let me know if
> you strongly feel we should call tegra_pcie_dw_host_init() instead of
> goto here. I'll change it.

I did not say we should call tegra_pcie_dw_host_init(), sorry for
not being clear. What I asked is factoring out registers programming
in a function and call it where core_init: label is and call it
again if DLF enablement causes link up to fail.

[...]

> > > +static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
> > > +					  bool enable)
> > > +{
> > > +	struct mrq_uphy_response resp;
> > > +	struct tegra_bpmp_message msg;
> > > +	struct mrq_uphy_request req;
> > > +	int err;
> > > +
> > > +	if (pcie->cid == 5)
> > > +		return 0;
> > 
> > What's wrong with cid == 5 ? Explain please.
> Controller with ID=5 doesn't need any programming to enable it which is
> done here through calling firmware API.
> 
> > 
> > > +	memset(&req, 0, sizeof(req));
> > > +	memset(&resp, 0, sizeof(resp));
> > > +
> > > +	req.cmd = CMD_UPHY_PCIE_CONTROLLER_STATE;
> > > +	req.controller_state.pcie_controller = pcie->cid;
> > > +	req.controller_state.enable = enable;
> > > +
> > > +	memset(&msg, 0, sizeof(msg));
> > > +	msg.mrq = MRQ_UPHY;
> > > +	msg.tx.data = &req;
> > > +	msg.tx.size = sizeof(req);
> > > +	msg.rx.data = &resp;
> > > +	msg.rx.size = sizeof(resp);
> > > +
> > > +	if (irqs_disabled())
> > 
> > Can you explain to me what this check is meant to achieve please ?
> Firmware interface provides different APIs to be called when there are
> no interrupts enabled in the system (noirq context) and otherwise
> hence checking that situation here and calling appropriate API.

That's what I am questioning. Being called from {suspend/resume}_noirq()
callbacks (if that's the code path this check caters for) does not mean
irqs_disabled() == true.

Actually, if tegra_bpmp_transfer() requires IRQs to be enabled you may
even end up in a situation where that blocking call does not wake up
because the IRQ in question was disabled in the NOIRQ suspend/resume
phase.

[...]

> > > +static int tegra_pcie_dw_probe(struct platform_device *pdev)
> > > +{
> > > +	const struct tegra_pcie_soc *data;
> > > +	struct device *dev = &pdev->dev;
> > > +	struct resource *atu_dma_res;
> > > +	struct tegra_pcie_dw *pcie;
> > > +	struct resource *dbi_res;
> > > +	struct pcie_port *pp;
> > > +	struct dw_pcie *pci;
> > > +	struct phy **phys;
> > > +	char *name;
> > > +	int ret;
> > > +	u32 i;
> > > +
> > > +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> > > +	if (!pcie)
> > > +		return -ENOMEM;
> > > +
> > > +	pci = &pcie->pci;
> > > +	pci->dev = &pdev->dev;
> > > +	pci->ops = &tegra_dw_pcie_ops;
> > > +	pp = &pci->pp;
> > > +	pcie->dev = &pdev->dev;
> > > +
> > > +	data = (struct tegra_pcie_soc *)of_device_get_match_data(dev);
> > > +	if (!data)
> > > +		return -EINVAL;
> > > +	pcie->mode = (enum dw_pcie_device_mode)data->mode;
> > > +
> > > +	ret = tegra_pcie_dw_parse_dt(pcie);
> > > +	if (ret < 0) {
> > > +		dev_err(dev, "Failed to parse device tree: %d\n", ret);
> > > +		return ret;
> > > +	}
> > > +
> > > +	pcie->pex_ctl_supply = devm_regulator_get(dev, "vddio-pex-ctl");
> > > +	if (IS_ERR(pcie->pex_ctl_supply)) {
> > > +		dev_err(dev, "Failed to get regulator: %ld\n",
> > > +			PTR_ERR(pcie->pex_ctl_supply));
> > > +		return PTR_ERR(pcie->pex_ctl_supply);
> > > +	}
> > > +
> > > +	pcie->core_clk = devm_clk_get(dev, "core");
> > > +	if (IS_ERR(pcie->core_clk)) {
> > > +		dev_err(dev, "Failed to get core clock: %ld\n",
> > > +			PTR_ERR(pcie->core_clk));
> > > +		return PTR_ERR(pcie->core_clk);
> > > +	}
> > > +
> > > +	pcie->appl_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > > +						      "appl");
> > > +	if (!pcie->appl_res) {
> > > +		dev_err(dev, "Failed to find \"appl\" region\n");
> > > +		return PTR_ERR(pcie->appl_res);
> > > +	}
> > > +	pcie->appl_base = devm_ioremap_resource(dev, pcie->appl_res);
> > > +	if (IS_ERR(pcie->appl_base))
> > > +		return PTR_ERR(pcie->appl_base);
> > > +
> > > +	pcie->core_apb_rst = devm_reset_control_get(dev, "apb");
> > > +	if (IS_ERR(pcie->core_apb_rst)) {
> > > +		dev_err(dev, "Failed to get APB reset: %ld\n",
> > > +			PTR_ERR(pcie->core_apb_rst));
> > > +		return PTR_ERR(pcie->core_apb_rst);
> > > +	}
> > > +
> > > +	phys = devm_kcalloc(dev, pcie->phy_count, sizeof(*phys), GFP_KERNEL);
> > > +	if (!phys)
> > > +		return PTR_ERR(phys);
> > > +
> > > +	for (i = 0; i < pcie->phy_count; i++) {
> > > +		name = kasprintf(GFP_KERNEL, "p2u-%u", i);
> > > +		if (!name) {
> > > +			dev_err(dev, "Failed to create P2U string\n");
> > > +			return -ENOMEM;
> > > +		}
> > > +		phys[i] = devm_phy_get(dev, name);
> > > +		kfree(name);
> > > +		if (IS_ERR(phys[i])) {
> > > +			ret = PTR_ERR(phys[i]);
> > > +			dev_err(dev, "Failed to get PHY: %d\n", ret);
> > > +			return ret;
> > > +		}
> > > +	}
> > > +
> > > +	pcie->phys = phys;
> > > +
> > > +	dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
> > > +	if (!dbi_res) {
> > > +		dev_err(dev, "Failed to find \"dbi\" region\n");
> > > +		return PTR_ERR(dbi_res);
> > > +	}
> > > +	pcie->dbi_res = dbi_res;
> > > +
> > > +	pci->dbi_base = devm_ioremap_resource(dev, dbi_res);
> > > +	if (IS_ERR(pci->dbi_base))
> > > +		return PTR_ERR(pci->dbi_base);
> > > +
> > > +	/* Tegra HW locates DBI2 at a fixed offset from DBI */
> > > +	pci->dbi_base2 = pci->dbi_base + 0x1000;
> > > +
> > > +	atu_dma_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > > +						   "atu_dma");
> > > +	if (!atu_dma_res) {
> > > +		dev_err(dev, "Failed to find \"atu_dma\" region\n");
> > > +		return PTR_ERR(atu_dma_res);
> > > +	}
> > > +	pcie->atu_dma_res = atu_dma_res;
> > > +	pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);
> > > +	if (IS_ERR(pci->atu_base))
> > > +		return PTR_ERR(pci->atu_base);
> > > +
> > > +	pcie->core_rst = devm_reset_control_get(dev, "core");
> > > +	if (IS_ERR(pcie->core_rst)) {
> > > +		dev_err(dev, "Failed to get core reset: %ld\n",
> > > +			PTR_ERR(pcie->core_rst));
> > > +		return PTR_ERR(pcie->core_rst);
> > > +	}
> > > +
> > > +	pp->irq = platform_get_irq_byname(pdev, "intr");
> > > +	if (!pp->irq) {
> > > +		dev_err(dev, "Failed to get \"intr\" interrupt\n");
> > > +		return -ENODEV;
> > > +	}
> > > +
> > > +	ret = devm_request_irq(dev, pp->irq, tegra_pcie_irq_handler,
> > > +			       IRQF_SHARED, "tegra-pcie-intr", pcie);
> > > +	if (ret) {
> > > +		dev_err(dev, "Failed to request IRQ %d: %d\n", pp->irq, ret);
> > > +		return ret;
> > > +	}
> > > +
> > > +	pcie->bpmp = tegra_bpmp_get(dev);
> > > +	if (IS_ERR(pcie->bpmp))
> > > +		return PTR_ERR(pcie->bpmp);
> > > +
> > > +	platform_set_drvdata(pdev, pcie);
> > > +
> > > +	if (pcie->mode == DW_PCIE_RC_TYPE) {
> > > +		ret = tegra_pcie_config_rp(pcie);
> > > +		if (ret && ret != -ENOMEDIUM)
> > > +			goto fail;
> > > +		else
> > > +			return 0;
> > 
> > So if the link is not up we still go ahead and make probe
> > succeed. What for ?
> We may need root port to be available to support hot-plugging of
> endpoint devices, so, we don't fail the probe.

We need it or we don't. If you do support hotplugging of endpoint
devices point me at the code, otherwise link up failure means
failure to probe.

> > > +	}
> > > +
> > > +fail:
> > > +	tegra_bpmp_put(pcie->bpmp);
> > > +	return ret;
> > > +}
> > > +
> > > +static int tegra_pcie_dw_remove(struct platform_device *pdev)
> > > +{
> > > +	struct tegra_pcie_dw *pcie = platform_get_drvdata(pdev);
> > > +
> > > +	if (pcie->mode != DW_PCIE_RC_TYPE)
> > > +		return 0;
> > > +
> > > +	if (!pcie->link_state)
> > > +		return 0;
> > > +
> > > +	debugfs_remove_recursive(pcie->debugfs);
> > > +	tegra_pcie_deinit_controller(pcie);
> > > +	pm_runtime_put_sync(pcie->dev);
> > > +	pm_runtime_disable(pcie->dev);
> > > +	tegra_bpmp_put(pcie->bpmp);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int tegra_pcie_dw_suspend_late(struct device *dev)
> > > +{
> > > +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
> > > +	u32 val;
> > > +
> > > +	if (!pcie->link_state)
> > > +		return 0;
> > > +
> > > +	/* Enable HW_HOT_RST mode */
> > > +	val = appl_readl(pcie, APPL_CTRL);
> > > +	val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
> > > +		 APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
> > > +	val |= APPL_CTRL_HW_HOT_RST_EN;
> > > +	appl_writel(pcie, val, APPL_CTRL);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int tegra_pcie_dw_suspend_noirq(struct device *dev)
> > > +{
> > > +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
> > > +
> > > +	if (!pcie->link_state)
> > > +		return 0;
> > > +
> > > +	/* Save MSI interrupt vector */
> > > +	pcie->msi_ctrl_int = dw_pcie_readl_dbi(&pcie->pci,
> > > +					       PORT_LOGIC_MSI_CTRL_INT_0_EN);
> > > +	tegra_pcie_downstream_dev_to_D0(pcie);
> > 
> > I think this requires some comments. AFAIU this is allowed by
> > the PCI specs (PCI Express Base 4.0 r1.0 September 29-2017,
> > 5.2 Link State Power Management). However, I would like to
> > understand how this plays with the D state the devices are left
> > in upon system suspend.
> > 
> > "As the following example illustrates, it is also possible to remove
> > power without first placing all Functions into D3Hot".
> > 
> > I assume that's what happens on this platform to allow L2 entry but
> > again, this needs clarification.
> Yes. It is true that in the case of Tegra194, it brings devices back
> to D0 before putting link to L2 state.

Comment it, extensively, so that anyone reading the code understands
why it is done so and what happens to devices then.

Lorenzo

On 7/12/2019 9:37 PM, Lorenzo Pieralisi wrote:
> On Fri, Jul 12, 2019 at 09:02:49PM +0530, Vidya Sagar wrote:
> 
> [...]
> 
>>>> +static irqreturn_t tegra_pcie_irq_handler(int irq, void *arg)
>>>> +{
>>>> +	struct tegra_pcie_dw *pcie = arg;
>>>> +
>>>> +	if (pcie->mode == DW_PCIE_RC_TYPE)
>>>> +		return tegra_pcie_rp_irq_handler(pcie);
>>>
>>> What's the point of registering the handler if mode != DW_PCIE_RC_TYPE ?
>> Currently this driver supports only root port mode but we have a plan
>> to add support for endpoint mode (as Tegra194 as dual mode
>> controllers) also in future and when that happens, we'll have a
>> corresponding tegra_pcie_ep_irq_handler() to take care of ep specific
>> interrupts.
> 
> Sure, that's why you should add tegra_pcie_dw->mode when it is needed,
> not in this patch.
Ok.

> 
> [...]
> 
>>>> +static int tegra_pcie_dw_host_init(struct pcie_port *pp)
>>>> +{
>>>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>>>> +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
>>>> +	u32 val, tmp, offset, speed;
>>>> +	unsigned int count;
>>>> +	u16 val_w;
>>>> +
>>>> +core_init:
>>>
>>> I think it would be cleaner to include all registers programming
>>> within a function and we remove this label (and goto) below.
>> Some background: As per spec r4.0 v1.0, downstream ports that support
>> 16.0 GT/s must support Scaled Flow Control (sec 3.4.2) and Tegra194's
>> downstream ports being 16.0 GT/s capable, enable scaled flow control
>> by having Data Link Feature (sec 7.7.4) enabled by default. There is
>> one endpoint (ASMedia USB3.0 controller) that doesn't link up with
>> root port because of this (i.e. DLF being enabled). The way we are
>> detecting this situation is to check for partial linkup i.e. one of
>> application logic registers (i.e. from "appl" region) says link is up
>> but the same is not reflected in configuration space of root port.
>> Recommendation from our hardware team in this situation is to disable
>> DLF in root port and try link up with endpoint again.  To achieve
>> this, we put the core through reset cycle, disable DLF and proceed
>> with configuring all other registers and check for link up.
>>
>> Initially in Patch-1, I didn't have goto statement but a recursion
>> with depth-1 (as the above situation occurs only once). It was
>> reviewed @ http://patchwork.ozlabs.org/patch/1065707/ and Thierry said
>> it would be simpler to use a goto instead of calling the same function
>> again. So, I modified the code accordingly. Please do let me know if
>> you strongly feel we should call tegra_pcie_dw_host_init() instead of
>> goto here. I'll change it.
> 
> I did not say we should call tegra_pcie_dw_host_init(), sorry for
> not being clear. What I asked is factoring out registers programming
> in a function and call it where core_init: label is and call it
> again if DLF enablement causes link up to fail.
Ok.

> 
> [...]
> 
>>>> +static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
>>>> +					  bool enable)
>>>> +{
>>>> +	struct mrq_uphy_response resp;
>>>> +	struct tegra_bpmp_message msg;
>>>> +	struct mrq_uphy_request req;
>>>> +	int err;
>>>> +
>>>> +	if (pcie->cid == 5)
>>>> +		return 0;
>>>
>>> What's wrong with cid == 5 ? Explain please.
>> Controller with ID=5 doesn't need any programming to enable it which is
>> done here through calling firmware API.
>>
>>>
>>>> +	memset(&req, 0, sizeof(req));
>>>> +	memset(&resp, 0, sizeof(resp));
>>>> +
>>>> +	req.cmd = CMD_UPHY_PCIE_CONTROLLER_STATE;
>>>> +	req.controller_state.pcie_controller = pcie->cid;
>>>> +	req.controller_state.enable = enable;
>>>> +
>>>> +	memset(&msg, 0, sizeof(msg));
>>>> +	msg.mrq = MRQ_UPHY;
>>>> +	msg.tx.data = &req;
>>>> +	msg.tx.size = sizeof(req);
>>>> +	msg.rx.data = &resp;
>>>> +	msg.rx.size = sizeof(resp);
>>>> +
>>>> +	if (irqs_disabled())
>>>
>>> Can you explain to me what this check is meant to achieve please ?
>> Firmware interface provides different APIs to be called when there are
>> no interrupts enabled in the system (noirq context) and otherwise
>> hence checking that situation here and calling appropriate API.
> 
> That's what I am questioning. Being called from {suspend/resume}_noirq()
> callbacks (if that's the code path this check caters for) does not mean
> irqs_disabled() == true.
Agree.
Actually, I got a hint of having this check from the following.
Both tegra_bpmp_transfer_atomic() and tegra_bpmp_transfer() are indirectly
called by APIs registered with .master_xfer() and .master_xfer_atomic() hooks of
struct i2c_algorithm and the decision to call which one of these is made using the
following check in i2c-core.h file.
static inline bool i2c_in_atomic_xfer_mode(void)
{
	return system_state > SYSTEM_RUNNING && irqs_disabled();
}
I think I should use this condition as is IIUC.
Please let me know if there are any concerns with this.

> 
> Actually, if tegra_bpmp_transfer() requires IRQs to be enabled you may
> even end up in a situation where that blocking call does not wake up
> because the IRQ in question was disabled in the NOIRQ suspend/resume
> phase.
> 
> [...]
> 
>>>> +static int tegra_pcie_dw_probe(struct platform_device *pdev)
>>>> +{
>>>> +	const struct tegra_pcie_soc *data;
>>>> +	struct device *dev = &pdev->dev;
>>>> +	struct resource *atu_dma_res;
>>>> +	struct tegra_pcie_dw *pcie;
>>>> +	struct resource *dbi_res;
>>>> +	struct pcie_port *pp;
>>>> +	struct dw_pcie *pci;
>>>> +	struct phy **phys;
>>>> +	char *name;
>>>> +	int ret;
>>>> +	u32 i;
>>>> +
>>>> +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
>>>> +	if (!pcie)
>>>> +		return -ENOMEM;
>>>> +
>>>> +	pci = &pcie->pci;
>>>> +	pci->dev = &pdev->dev;
>>>> +	pci->ops = &tegra_dw_pcie_ops;
>>>> +	pp = &pci->pp;
>>>> +	pcie->dev = &pdev->dev;
>>>> +
>>>> +	data = (struct tegra_pcie_soc *)of_device_get_match_data(dev);
>>>> +	if (!data)
>>>> +		return -EINVAL;
>>>> +	pcie->mode = (enum dw_pcie_device_mode)data->mode;
>>>> +
>>>> +	ret = tegra_pcie_dw_parse_dt(pcie);
>>>> +	if (ret < 0) {
>>>> +		dev_err(dev, "Failed to parse device tree: %d\n", ret);
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	pcie->pex_ctl_supply = devm_regulator_get(dev, "vddio-pex-ctl");
>>>> +	if (IS_ERR(pcie->pex_ctl_supply)) {
>>>> +		dev_err(dev, "Failed to get regulator: %ld\n",
>>>> +			PTR_ERR(pcie->pex_ctl_supply));
>>>> +		return PTR_ERR(pcie->pex_ctl_supply);
>>>> +	}
>>>> +
>>>> +	pcie->core_clk = devm_clk_get(dev, "core");
>>>> +	if (IS_ERR(pcie->core_clk)) {
>>>> +		dev_err(dev, "Failed to get core clock: %ld\n",
>>>> +			PTR_ERR(pcie->core_clk));
>>>> +		return PTR_ERR(pcie->core_clk);
>>>> +	}
>>>> +
>>>> +	pcie->appl_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>>>> +						      "appl");
>>>> +	if (!pcie->appl_res) {
>>>> +		dev_err(dev, "Failed to find \"appl\" region\n");
>>>> +		return PTR_ERR(pcie->appl_res);
>>>> +	}
>>>> +	pcie->appl_base = devm_ioremap_resource(dev, pcie->appl_res);
>>>> +	if (IS_ERR(pcie->appl_base))
>>>> +		return PTR_ERR(pcie->appl_base);
>>>> +
>>>> +	pcie->core_apb_rst = devm_reset_control_get(dev, "apb");
>>>> +	if (IS_ERR(pcie->core_apb_rst)) {
>>>> +		dev_err(dev, "Failed to get APB reset: %ld\n",
>>>> +			PTR_ERR(pcie->core_apb_rst));
>>>> +		return PTR_ERR(pcie->core_apb_rst);
>>>> +	}
>>>> +
>>>> +	phys = devm_kcalloc(dev, pcie->phy_count, sizeof(*phys), GFP_KERNEL);
>>>> +	if (!phys)
>>>> +		return PTR_ERR(phys);
>>>> +
>>>> +	for (i = 0; i < pcie->phy_count; i++) {
>>>> +		name = kasprintf(GFP_KERNEL, "p2u-%u", i);
>>>> +		if (!name) {
>>>> +			dev_err(dev, "Failed to create P2U string\n");
>>>> +			return -ENOMEM;
>>>> +		}
>>>> +		phys[i] = devm_phy_get(dev, name);
>>>> +		kfree(name);
>>>> +		if (IS_ERR(phys[i])) {
>>>> +			ret = PTR_ERR(phys[i]);
>>>> +			dev_err(dev, "Failed to get PHY: %d\n", ret);
>>>> +			return ret;
>>>> +		}
>>>> +	}
>>>> +
>>>> +	pcie->phys = phys;
>>>> +
>>>> +	dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
>>>> +	if (!dbi_res) {
>>>> +		dev_err(dev, "Failed to find \"dbi\" region\n");
>>>> +		return PTR_ERR(dbi_res);
>>>> +	}
>>>> +	pcie->dbi_res = dbi_res;
>>>> +
>>>> +	pci->dbi_base = devm_ioremap_resource(dev, dbi_res);
>>>> +	if (IS_ERR(pci->dbi_base))
>>>> +		return PTR_ERR(pci->dbi_base);
>>>> +
>>>> +	/* Tegra HW locates DBI2 at a fixed offset from DBI */
>>>> +	pci->dbi_base2 = pci->dbi_base + 0x1000;
>>>> +
>>>> +	atu_dma_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>>>> +						   "atu_dma");
>>>> +	if (!atu_dma_res) {
>>>> +		dev_err(dev, "Failed to find \"atu_dma\" region\n");
>>>> +		return PTR_ERR(atu_dma_res);
>>>> +	}
>>>> +	pcie->atu_dma_res = atu_dma_res;
>>>> +	pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);
>>>> +	if (IS_ERR(pci->atu_base))
>>>> +		return PTR_ERR(pci->atu_base);
>>>> +
>>>> +	pcie->core_rst = devm_reset_control_get(dev, "core");
>>>> +	if (IS_ERR(pcie->core_rst)) {
>>>> +		dev_err(dev, "Failed to get core reset: %ld\n",
>>>> +			PTR_ERR(pcie->core_rst));
>>>> +		return PTR_ERR(pcie->core_rst);
>>>> +	}
>>>> +
>>>> +	pp->irq = platform_get_irq_byname(pdev, "intr");
>>>> +	if (!pp->irq) {
>>>> +		dev_err(dev, "Failed to get \"intr\" interrupt\n");
>>>> +		return -ENODEV;
>>>> +	}
>>>> +
>>>> +	ret = devm_request_irq(dev, pp->irq, tegra_pcie_irq_handler,
>>>> +			       IRQF_SHARED, "tegra-pcie-intr", pcie);
>>>> +	if (ret) {
>>>> +		dev_err(dev, "Failed to request IRQ %d: %d\n", pp->irq, ret);
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	pcie->bpmp = tegra_bpmp_get(dev);
>>>> +	if (IS_ERR(pcie->bpmp))
>>>> +		return PTR_ERR(pcie->bpmp);
>>>> +
>>>> +	platform_set_drvdata(pdev, pcie);
>>>> +
>>>> +	if (pcie->mode == DW_PCIE_RC_TYPE) {
>>>> +		ret = tegra_pcie_config_rp(pcie);
>>>> +		if (ret && ret != -ENOMEDIUM)
>>>> +			goto fail;
>>>> +		else
>>>> +			return 0;
>>>
>>> So if the link is not up we still go ahead and make probe
>>> succeed. What for ?
>> We may need root port to be available to support hot-plugging of
>> endpoint devices, so, we don't fail the probe.
> 
> We need it or we don't. If you do support hotplugging of endpoint
> devices point me at the code, otherwise link up failure means
> failure to probe.
Currently hotplugging of endpoint is not supported, but it is one of the use cases that
we may add support for in future.
But, why should we fail probe if link up doesn't happen? As such, nothing went wrong in
terms of root port initialization right?
I checked other DWC based implementations and following are not failing the probe
pci-dra7xx.c, pcie-armada8k.c, pcie-artpec6.c, pcie-histb.c, pcie-kirin.c, pcie-spear13xx.c,
pci-exynos.c, pci-imx6.c, pci-keystone.c, pci-layerscape.c

Although following do fail the probe if link is not up.
pcie-qcom.c, pcie-uniphier.c, pci-meson.c

So, to me, it looks more like a choice we can make whether to fail the probe or not and in this
case we are choosing not to fail.
> 
>>>> +	}
>>>> +
>>>> +fail:
>>>> +	tegra_bpmp_put(pcie->bpmp);
>>>> +	return ret;
>>>> +}
>>>> +
>>>> +static int tegra_pcie_dw_remove(struct platform_device *pdev)
>>>> +{
>>>> +	struct tegra_pcie_dw *pcie = platform_get_drvdata(pdev);
>>>> +
>>>> +	if (pcie->mode != DW_PCIE_RC_TYPE)
>>>> +		return 0;
>>>> +
>>>> +	if (!pcie->link_state)
>>>> +		return 0;
>>>> +
>>>> +	debugfs_remove_recursive(pcie->debugfs);
>>>> +	tegra_pcie_deinit_controller(pcie);
>>>> +	pm_runtime_put_sync(pcie->dev);
>>>> +	pm_runtime_disable(pcie->dev);
>>>> +	tegra_bpmp_put(pcie->bpmp);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int tegra_pcie_dw_suspend_late(struct device *dev)
>>>> +{
>>>> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
>>>> +	u32 val;
>>>> +
>>>> +	if (!pcie->link_state)
>>>> +		return 0;
>>>> +
>>>> +	/* Enable HW_HOT_RST mode */
>>>> +	val = appl_readl(pcie, APPL_CTRL);
>>>> +	val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
>>>> +		 APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
>>>> +	val |= APPL_CTRL_HW_HOT_RST_EN;
>>>> +	appl_writel(pcie, val, APPL_CTRL);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int tegra_pcie_dw_suspend_noirq(struct device *dev)
>>>> +{
>>>> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
>>>> +
>>>> +	if (!pcie->link_state)
>>>> +		return 0;
>>>> +
>>>> +	/* Save MSI interrupt vector */
>>>> +	pcie->msi_ctrl_int = dw_pcie_readl_dbi(&pcie->pci,
>>>> +					       PORT_LOGIC_MSI_CTRL_INT_0_EN);
>>>> +	tegra_pcie_downstream_dev_to_D0(pcie);
>>>
>>> I think this requires some comments. AFAIU this is allowed by
>>> the PCI specs (PCI Express Base 4.0 r1.0 September 29-2017,
>>> 5.2 Link State Power Management). However, I would like to
>>> understand how this plays with the D state the devices are left
>>> in upon system suspend.
>>>
>>> "As the following example illustrates, it is also possible to remove
>>> power without first placing all Functions into D3Hot".
>>>
>>> I assume that's what happens on this platform to allow L2 entry but
>>> again, this needs clarification.
>> Yes. It is true that in the case of Tegra194, it brings devices back
>> to D0 before putting link to L2 state.
> 
> Comment it, extensively, so that anyone reading the code understands
> why it is done so and what happens to devices then.
I added comment in tegra_pcie_deinit_controller() where this API is called
but I think I should move the comment inside tegra_pcie_downstream_dev_to_D0()
API and also add more info to it.
I'll take care of it in the next patch.

> 
> Lorenzo
>

On Sat, Jul 13, 2019 at 12:34:34PM +0530, Vidya Sagar wrote:

[...]

> > > > > +static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
> > > > > +					  bool enable)
> > > > > +{
> > > > > +	struct mrq_uphy_response resp;
> > > > > +	struct tegra_bpmp_message msg;
> > > > > +	struct mrq_uphy_request req;
> > > > > +	int err;
> > > > > +
> > > > > +	if (pcie->cid == 5)
> > > > > +		return 0;
> > > > 
> > > > What's wrong with cid == 5 ? Explain please.
> > > Controller with ID=5 doesn't need any programming to enable it which is
> > > done here through calling firmware API.
> > > 
> > > > 
> > > > > +	memset(&req, 0, sizeof(req));
> > > > > +	memset(&resp, 0, sizeof(resp));
> > > > > +
> > > > > +	req.cmd = CMD_UPHY_PCIE_CONTROLLER_STATE;
> > > > > +	req.controller_state.pcie_controller = pcie->cid;
> > > > > +	req.controller_state.enable = enable;
> > > > > +
> > > > > +	memset(&msg, 0, sizeof(msg));
> > > > > +	msg.mrq = MRQ_UPHY;
> > > > > +	msg.tx.data = &req;
> > > > > +	msg.tx.size = sizeof(req);
> > > > > +	msg.rx.data = &resp;
> > > > > +	msg.rx.size = sizeof(resp);
> > > > > +
> > > > > +	if (irqs_disabled())
> > > > 
> > > > Can you explain to me what this check is meant to achieve please ?
> > > Firmware interface provides different APIs to be called when there are
> > > no interrupts enabled in the system (noirq context) and otherwise
> > > hence checking that situation here and calling appropriate API.
> > 
> > That's what I am questioning. Being called from {suspend/resume}_noirq()
> > callbacks (if that's the code path this check caters for) does not mean
> > irqs_disabled() == true.
> Agree.
> Actually, I got a hint of having this check from the following.
> Both tegra_bpmp_transfer_atomic() and tegra_bpmp_transfer() are indirectly
> called by APIs registered with .master_xfer() and .master_xfer_atomic() hooks of
> struct i2c_algorithm and the decision to call which one of these is made using the
> following check in i2c-core.h file.
> static inline bool i2c_in_atomic_xfer_mode(void)
> {
> 	return system_state > SYSTEM_RUNNING && irqs_disabled();
> }
> I think I should use this condition as is IIUC.
> Please let me know if there are any concerns with this.

It is not a concern, it is just that I don't understand how this code
can be called with IRQs disabled, if you can give me an execution path I
am happy to leave the check there. On top of that, when called from
suspend NOIRQ context, it is likely to use the blocking API (because
IRQs aren't disabled at CPU level) behind which there is most certainly
an IRQ required to wake the thread up and if the IRQ in question was
disabled in the suspend NOIRQ phase this code is likely to deadlock.

I want to make sure we can justify adding this check, I do not
want to add it because we think it can be needed when it may not
be needed at all (and it gets copy and pasted over and over again
in other drivers).

> > Actually, if tegra_bpmp_transfer() requires IRQs to be enabled you may
> > even end up in a situation where that blocking call does not wake up
> > because the IRQ in question was disabled in the NOIRQ suspend/resume
> > phase.
> > 
> > [...]
> > 
> > > > > +static int tegra_pcie_dw_probe(struct platform_device *pdev)
> > > > > +{
> > > > > +	const struct tegra_pcie_soc *data;
> > > > > +	struct device *dev = &pdev->dev;
> > > > > +	struct resource *atu_dma_res;
> > > > > +	struct tegra_pcie_dw *pcie;
> > > > > +	struct resource *dbi_res;
> > > > > +	struct pcie_port *pp;
> > > > > +	struct dw_pcie *pci;
> > > > > +	struct phy **phys;
> > > > > +	char *name;
> > > > > +	int ret;
> > > > > +	u32 i;
> > > > > +
> > > > > +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> > > > > +	if (!pcie)
> > > > > +		return -ENOMEM;
> > > > > +
> > > > > +	pci = &pcie->pci;
> > > > > +	pci->dev = &pdev->dev;
> > > > > +	pci->ops = &tegra_dw_pcie_ops;
> > > > > +	pp = &pci->pp;
> > > > > +	pcie->dev = &pdev->dev;
> > > > > +
> > > > > +	data = (struct tegra_pcie_soc *)of_device_get_match_data(dev);
> > > > > +	if (!data)
> > > > > +		return -EINVAL;
> > > > > +	pcie->mode = (enum dw_pcie_device_mode)data->mode;
> > > > > +
> > > > > +	ret = tegra_pcie_dw_parse_dt(pcie);
> > > > > +	if (ret < 0) {
> > > > > +		dev_err(dev, "Failed to parse device tree: %d\n", ret);
> > > > > +		return ret;
> > > > > +	}
> > > > > +
> > > > > +	pcie->pex_ctl_supply = devm_regulator_get(dev, "vddio-pex-ctl");
> > > > > +	if (IS_ERR(pcie->pex_ctl_supply)) {
> > > > > +		dev_err(dev, "Failed to get regulator: %ld\n",
> > > > > +			PTR_ERR(pcie->pex_ctl_supply));
> > > > > +		return PTR_ERR(pcie->pex_ctl_supply);
> > > > > +	}
> > > > > +
> > > > > +	pcie->core_clk = devm_clk_get(dev, "core");
> > > > > +	if (IS_ERR(pcie->core_clk)) {
> > > > > +		dev_err(dev, "Failed to get core clock: %ld\n",
> > > > > +			PTR_ERR(pcie->core_clk));
> > > > > +		return PTR_ERR(pcie->core_clk);
> > > > > +	}
> > > > > +
> > > > > +	pcie->appl_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > > > > +						      "appl");
> > > > > +	if (!pcie->appl_res) {
> > > > > +		dev_err(dev, "Failed to find \"appl\" region\n");
> > > > > +		return PTR_ERR(pcie->appl_res);
> > > > > +	}
> > > > > +	pcie->appl_base = devm_ioremap_resource(dev, pcie->appl_res);
> > > > > +	if (IS_ERR(pcie->appl_base))
> > > > > +		return PTR_ERR(pcie->appl_base);
> > > > > +
> > > > > +	pcie->core_apb_rst = devm_reset_control_get(dev, "apb");
> > > > > +	if (IS_ERR(pcie->core_apb_rst)) {
> > > > > +		dev_err(dev, "Failed to get APB reset: %ld\n",
> > > > > +			PTR_ERR(pcie->core_apb_rst));
> > > > > +		return PTR_ERR(pcie->core_apb_rst);
> > > > > +	}
> > > > > +
> > > > > +	phys = devm_kcalloc(dev, pcie->phy_count, sizeof(*phys), GFP_KERNEL);
> > > > > +	if (!phys)
> > > > > +		return PTR_ERR(phys);
> > > > > +
> > > > > +	for (i = 0; i < pcie->phy_count; i++) {
> > > > > +		name = kasprintf(GFP_KERNEL, "p2u-%u", i);
> > > > > +		if (!name) {
> > > > > +			dev_err(dev, "Failed to create P2U string\n");
> > > > > +			return -ENOMEM;
> > > > > +		}
> > > > > +		phys[i] = devm_phy_get(dev, name);
> > > > > +		kfree(name);
> > > > > +		if (IS_ERR(phys[i])) {
> > > > > +			ret = PTR_ERR(phys[i]);
> > > > > +			dev_err(dev, "Failed to get PHY: %d\n", ret);
> > > > > +			return ret;
> > > > > +		}
> > > > > +	}
> > > > > +
> > > > > +	pcie->phys = phys;
> > > > > +
> > > > > +	dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
> > > > > +	if (!dbi_res) {
> > > > > +		dev_err(dev, "Failed to find \"dbi\" region\n");
> > > > > +		return PTR_ERR(dbi_res);
> > > > > +	}
> > > > > +	pcie->dbi_res = dbi_res;
> > > > > +
> > > > > +	pci->dbi_base = devm_ioremap_resource(dev, dbi_res);
> > > > > +	if (IS_ERR(pci->dbi_base))
> > > > > +		return PTR_ERR(pci->dbi_base);
> > > > > +
> > > > > +	/* Tegra HW locates DBI2 at a fixed offset from DBI */
> > > > > +	pci->dbi_base2 = pci->dbi_base + 0x1000;
> > > > > +
> > > > > +	atu_dma_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > > > > +						   "atu_dma");
> > > > > +	if (!atu_dma_res) {
> > > > > +		dev_err(dev, "Failed to find \"atu_dma\" region\n");
> > > > > +		return PTR_ERR(atu_dma_res);
> > > > > +	}
> > > > > +	pcie->atu_dma_res = atu_dma_res;
> > > > > +	pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);
> > > > > +	if (IS_ERR(pci->atu_base))
> > > > > +		return PTR_ERR(pci->atu_base);
> > > > > +
> > > > > +	pcie->core_rst = devm_reset_control_get(dev, "core");
> > > > > +	if (IS_ERR(pcie->core_rst)) {
> > > > > +		dev_err(dev, "Failed to get core reset: %ld\n",
> > > > > +			PTR_ERR(pcie->core_rst));
> > > > > +		return PTR_ERR(pcie->core_rst);
> > > > > +	}
> > > > > +
> > > > > +	pp->irq = platform_get_irq_byname(pdev, "intr");
> > > > > +	if (!pp->irq) {
> > > > > +		dev_err(dev, "Failed to get \"intr\" interrupt\n");
> > > > > +		return -ENODEV;
> > > > > +	}
> > > > > +
> > > > > +	ret = devm_request_irq(dev, pp->irq, tegra_pcie_irq_handler,
> > > > > +			       IRQF_SHARED, "tegra-pcie-intr", pcie);
> > > > > +	if (ret) {
> > > > > +		dev_err(dev, "Failed to request IRQ %d: %d\n", pp->irq, ret);
> > > > > +		return ret;
> > > > > +	}
> > > > > +
> > > > > +	pcie->bpmp = tegra_bpmp_get(dev);
> > > > > +	if (IS_ERR(pcie->bpmp))
> > > > > +		return PTR_ERR(pcie->bpmp);
> > > > > +
> > > > > +	platform_set_drvdata(pdev, pcie);
> > > > > +
> > > > > +	if (pcie->mode == DW_PCIE_RC_TYPE) {
> > > > > +		ret = tegra_pcie_config_rp(pcie);
> > > > > +		if (ret && ret != -ENOMEDIUM)
> > > > > +			goto fail;
> > > > > +		else
> > > > > +			return 0;
> > > > 
> > > > So if the link is not up we still go ahead and make probe
> > > > succeed. What for ?
> > > We may need root port to be available to support hot-plugging of
> > > endpoint devices, so, we don't fail the probe.
> > 
> > We need it or we don't. If you do support hotplugging of endpoint
> > devices point me at the code, otherwise link up failure means
> > failure to probe.
> Currently hotplugging of endpoint is not supported, but it is one of
> the use cases that we may add support for in future. 

You should elaborate on this, I do not understand what you mean,
either the root port(s) supports hotplug or it does not.

> But, why should we fail probe if link up doesn't happen? As such,
> nothing went wrong in terms of root port initialization right?  I
> checked other DWC based implementations and following are not failing
> the probe pci-dra7xx.c, pcie-armada8k.c, pcie-artpec6.c, pcie-histb.c,
> pcie-kirin.c, pcie-spear13xx.c, pci-exynos.c, pci-imx6.c,
> pci-keystone.c, pci-layerscape.c
> 
> Although following do fail the probe if link is not up.  pcie-qcom.c,
> pcie-uniphier.c, pci-meson.c
> 
> So, to me, it looks more like a choice we can make whether to fail the
> probe or not and in this case we are choosing not to fail.

I disagree. I had an offline chat with Bjorn and whether link-up should
fail the probe or not depends on whether the root port(s) is hotplug
capable or not and this in turn relies on the root port "Slot
implemented" bit in the PCI Express capabilities register.

It is a choice but it should be based on evidence.

Lorenzo

On Tue, Jul 16, 2019 at 12:22:25PM +0100, Lorenzo Pieralisi wrote:
> On Sat, Jul 13, 2019 at 12:34:34PM +0530, Vidya Sagar wrote:

> > > > > So if the link is not up we still go ahead and make probe
> > > > > succeed. What for ?
> > > > We may need root port to be available to support hot-plugging of
> > > > endpoint devices, so, we don't fail the probe.
> > > 
> > > We need it or we don't. If you do support hotplugging of endpoint
> > > devices point me at the code, otherwise link up failure means
> > > failure to probe.
> > Currently hotplugging of endpoint is not supported, but it is one of
> > the use cases that we may add support for in future. 
> 
> You should elaborate on this, I do not understand what you mean,
> either the root port(s) supports hotplug or it does not.
> 
> > But, why should we fail probe if link up doesn't happen? As such,
> > nothing went wrong in terms of root port initialization right?  I
> > checked other DWC based implementations and following are not failing
> > the probe pci-dra7xx.c, pcie-armada8k.c, pcie-artpec6.c, pcie-histb.c,
> > pcie-kirin.c, pcie-spear13xx.c, pci-exynos.c, pci-imx6.c,
> > pci-keystone.c, pci-layerscape.c
> > 
> > Although following do fail the probe if link is not up.  pcie-qcom.c,
> > pcie-uniphier.c, pci-meson.c
> > 
> > So, to me, it looks more like a choice we can make whether to fail the
> > probe or not and in this case we are choosing not to fail.
> 
> I disagree. I had an offline chat with Bjorn and whether link-up should
> fail the probe or not depends on whether the root port(s) is hotplug
> capable or not and this in turn relies on the root port "Slot
> implemented" bit in the PCI Express capabilities register.

There might be a little more we can talk about in this regard.  I did
bring up the "Slot implemented" bit, but after thinking about it more,
I don't really think the host bridge driver should be looking at that.
That's a PCIe concept, and it's really *downstream* from the host
bridge itself.  The host bridge is logically a device on the CPU bus,
not the PCI bus.

I'm starting to think that the host bridge driver probe should be
disconnected from question of whether the root port links are up.

Logically, the host bridge driver connects the CPU bus to a PCI root
bus, so it converts CPU-side accesses to PCI config, memory, or I/O
port transactions.  Given that, the PCI core can enumerate devices on
the root bus and downstream buses.

Devices on the root bus typically include Root Ports, but might also
include endpoints, Root Complex Integrated Endpoints, Root Complex
Event Collectors, etc.  I think in principle, we would want the host
bridge probe to succeed so we can use these devices even if none of
the Root Ports have a link.

If a Root Port is present, I think users will expect to see it in the
"lspci" output, even if its downstream link is not up.  That will
enable things like manually poking the Root Port via "setpci" for
debug.  And if it has a connector, the generic pciehp should be able
to handle hot-add events without any special help from the host bridge
driver.

On ACPI systems there is no concept of the host bridge driver probe
failing because of lack of link on a Root Port.  If a Root Port
doesn't have an operational link, we still keep the pci_root.c driver,
and we'll enumerate the Root Port itself.  So I tend to think DT
systems should behave the same way, i.e., the driver probe should
succeed unless it fails to allocate resources or something similar.  I
think this is analogous to a NIC or USB adapter driver, where the
probe succeeds even if there's no network cable or USB device
attached.

Bjorn

> -----Original Message-----
> From: devicetree-owner@vger.kernel.org <devicetree-owner@vger.kernel.org>
> On Behalf Of Bjorn Helgaas
> Sent: Wednesday, July 17, 2019 12:30 AM
> To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Cc: Vidya Sagar <vidyas@nvidia.com>; robh+dt@kernel.org;
> mark.rutland@arm.com; thierry.reding@gmail.com; Jonathan Hunter
> <jonathanh@nvidia.com>; kishon@ti.com; catalin.marinas@arm.com;
> will.deacon@arm.com; jingoohan1@gmail.com;
> gustavo.pimentel@synopsys.com; digetx@gmail.com; Mikko Perttunen
> <mperttunen@nvidia.com>; linux-pci@vger.kernel.org;
> devicetree@vger.kernel.org; linux-tegra@vger.kernel.org; linux-
> kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org; Krishna Thota
> <kthota@nvidia.com>; Manikanta Maddireddy <mmaddireddy@nvidia.com>;
> sagar.tv@gmail.com
> Subject: Re: [PATCH V13 12/12] PCI: tegra: Add Tegra194 PCIe support
> 
> On Tue, Jul 16, 2019 at 12:22:25PM +0100, Lorenzo Pieralisi wrote:
> > On Sat, Jul 13, 2019 at 12:34:34PM +0530, Vidya Sagar wrote:
> 
> > > > > > So if the link is not up we still go ahead and make probe
> > > > > > succeed. What for ?
> > > > > We may need root port to be available to support hot-plugging of
> > > > > endpoint devices, so, we don't fail the probe.
> > > >
> > > > We need it or we don't. If you do support hotplugging of endpoint
> > > > devices point me at the code, otherwise link up failure means
> > > > failure to probe.
> > > Currently hotplugging of endpoint is not supported, but it is one of
> > > the use cases that we may add support for in future.
> >
> > You should elaborate on this, I do not understand what you mean,
> > either the root port(s) supports hotplug or it does not.
> >
> > > But, why should we fail probe if link up doesn't happen? As such,
> > > nothing went wrong in terms of root port initialization right?  I
> > > checked other DWC based implementations and following are not
> > > failing the probe pci-dra7xx.c, pcie-armada8k.c, pcie-artpec6.c,
> > > pcie-histb.c, pcie-kirin.c, pcie-spear13xx.c, pci-exynos.c,
> > > pci-imx6.c, pci-keystone.c, pci-layerscape.c
> > >
> > > Although following do fail the probe if link is not up.
> > > pcie-qcom.c, pcie-uniphier.c, pci-meson.c
> > >
> > > So, to me, it looks more like a choice we can make whether to fail
> > > the probe or not and in this case we are choosing not to fail.
> >
> > I disagree. I had an offline chat with Bjorn and whether link-up
> > should fail the probe or not depends on whether the root port(s) is
> > hotplug capable or not and this in turn relies on the root port "Slot
> > implemented" bit in the PCI Express capabilities register.
> 
> There might be a little more we can talk about in this regard.  I did bring up the
> "Slot implemented" bit, but after thinking about it more, I don't really think the
> host bridge driver should be looking at that.
> That's a PCIe concept, and it's really *downstream* from the host bridge itself.
> The host bridge is logically a device on the CPU bus, not the PCI bus.
> 
> I'm starting to think that the host bridge driver probe should be disconnected
> from question of whether the root port links are up.
> 
> Logically, the host bridge driver connects the CPU bus to a PCI root bus, so it
> converts CPU-side accesses to PCI config, memory, or I/O port transactions.
> Given that, the PCI core can enumerate devices on the root bus and downstream
> buses.
> 
> Devices on the root bus typically include Root Ports, but might also include
> endpoints, Root Complex Integrated Endpoints, Root Complex Event Collectors,
> etc.  I think in principle, we would want the host bridge probe to succeed so we
> can use these devices even if none of the Root Ports have a link.
> 
> If a Root Port is present, I think users will expect to see it in the "lspci" output,
> even if its downstream link is not up.  That will enable things like manually
> poking the Root Port via "setpci" for debug.  And if it has a connector, the
> generic pciehp should be able to handle hot-add events without any special help
> from the host bridge driver.
> 
> On ACPI systems there is no concept of the host bridge driver probe failing
> because of lack of link on a Root Port.  If a Root Port doesn't have an
> operational link, we still keep the pci_root.c driver, and we'll enumerate the
> Root Port itself.  So I tend to think DT systems should behave the same way, i.e.,
> the driver probe should succeed unless it fails to allocate resources or something
> similar.  I think this is analogous to a NIC or USB adapter driver, where the probe
> succeeds even if there's no network cable or USB device attached.
> 
> Bjorn
Thanks Bjorn for your valuable inputs. I hope we are good here to not power down host
even if there are no endpoints detected.

- Vidya Sagar

On 7/16/2019 4:52 PM, Lorenzo Pieralisi wrote:
> On Sat, Jul 13, 2019 at 12:34:34PM +0530, Vidya Sagar wrote:
> 
> [...]
> 
>>>>>> +static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
>>>>>> +					  bool enable)
>>>>>> +{
>>>>>> +	struct mrq_uphy_response resp;
>>>>>> +	struct tegra_bpmp_message msg;
>>>>>> +	struct mrq_uphy_request req;
>>>>>> +	int err;
>>>>>> +
>>>>>> +	if (pcie->cid == 5)
>>>>>> +		return 0;
>>>>>
>>>>> What's wrong with cid == 5 ? Explain please.
>>>> Controller with ID=5 doesn't need any programming to enable it which is
>>>> done here through calling firmware API.
>>>>
>>>>>
>>>>>> +	memset(&req, 0, sizeof(req));
>>>>>> +	memset(&resp, 0, sizeof(resp));
>>>>>> +
>>>>>> +	req.cmd = CMD_UPHY_PCIE_CONTROLLER_STATE;
>>>>>> +	req.controller_state.pcie_controller = pcie->cid;
>>>>>> +	req.controller_state.enable = enable;
>>>>>> +
>>>>>> +	memset(&msg, 0, sizeof(msg));
>>>>>> +	msg.mrq = MRQ_UPHY;
>>>>>> +	msg.tx.data = &req;
>>>>>> +	msg.tx.size = sizeof(req);
>>>>>> +	msg.rx.data = &resp;
>>>>>> +	msg.rx.size = sizeof(resp);
>>>>>> +
>>>>>> +	if (irqs_disabled())
>>>>>
>>>>> Can you explain to me what this check is meant to achieve please ?
>>>> Firmware interface provides different APIs to be called when there are
>>>> no interrupts enabled in the system (noirq context) and otherwise
>>>> hence checking that situation here and calling appropriate API.
>>>
>>> That's what I am questioning. Being called from {suspend/resume}_noirq()
>>> callbacks (if that's the code path this check caters for) does not mean
>>> irqs_disabled() == true.
>> Agree.
>> Actually, I got a hint of having this check from the following.
>> Both tegra_bpmp_transfer_atomic() and tegra_bpmp_transfer() are indirectly
>> called by APIs registered with .master_xfer() and .master_xfer_atomic() hooks of
>> struct i2c_algorithm and the decision to call which one of these is made using the
>> following check in i2c-core.h file.
>> static inline bool i2c_in_atomic_xfer_mode(void)
>> {
>> 	return system_state > SYSTEM_RUNNING && irqs_disabled();
>> }
>> I think I should use this condition as is IIUC.
>> Please let me know if there are any concerns with this.
> 
> It is not a concern, it is just that I don't understand how this code
> can be called with IRQs disabled, if you can give me an execution path I
> am happy to leave the check there. On top of that, when called from
> suspend NOIRQ context, it is likely to use the blocking API (because
> IRQs aren't disabled at CPU level) behind which there is most certainly
> an IRQ required to wake the thread up and if the IRQ in question was
> disabled in the suspend NOIRQ phase this code is likely to deadlock.
> 
> I want to make sure we can justify adding this check, I do not
> want to add it because we think it can be needed when it may not
> be needed at all (and it gets copy and pasted over and over again
> in other drivers).
I had a discussion internally about this and the prescribed usage of these APIs
seem to be that
use tegra_bpmp_transfer() in .probe() and other paths where interrupts are
enabled as this API needs interrupts to be enabled for its working.
Use tegra_bpmp_transfer_atomic() surrounded by local_irq_save()/local_irq_restore()
in other paths where interrupt servicing is disabled.
I'll go ahead and make next patch series with this if this looks fine to you.

> 
>>> Actually, if tegra_bpmp_transfer() requires IRQs to be enabled you may
>>> even end up in a situation where that blocking call does not wake up
>>> because the IRQ in question was disabled in the NOIRQ suspend/resume
>>> phase.
>>>
>>> [...]
>>>
>>>>>> +static int tegra_pcie_dw_probe(struct platform_device *pdev)
>>>>>> +{
>>>>>> +	const struct tegra_pcie_soc *data;
>>>>>> +	struct device *dev = &pdev->dev;
>>>>>> +	struct resource *atu_dma_res;
>>>>>> +	struct tegra_pcie_dw *pcie;
>>>>>> +	struct resource *dbi_res;
>>>>>> +	struct pcie_port *pp;
>>>>>> +	struct dw_pcie *pci;
>>>>>> +	struct phy **phys;
>>>>>> +	char *name;
>>>>>> +	int ret;
>>>>>> +	u32 i;
>>>>>> +
>>>>>> +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
>>>>>> +	if (!pcie)
>>>>>> +		return -ENOMEM;
>>>>>> +
>>>>>> +	pci = &pcie->pci;
>>>>>> +	pci->dev = &pdev->dev;
>>>>>> +	pci->ops = &tegra_dw_pcie_ops;
>>>>>> +	pp = &pci->pp;
>>>>>> +	pcie->dev = &pdev->dev;
>>>>>> +
>>>>>> +	data = (struct tegra_pcie_soc *)of_device_get_match_data(dev);
>>>>>> +	if (!data)
>>>>>> +		return -EINVAL;
>>>>>> +	pcie->mode = (enum dw_pcie_device_mode)data->mode;
>>>>>> +
>>>>>> +	ret = tegra_pcie_dw_parse_dt(pcie);
>>>>>> +	if (ret < 0) {
>>>>>> +		dev_err(dev, "Failed to parse device tree: %d\n", ret);
>>>>>> +		return ret;
>>>>>> +	}
>>>>>> +
>>>>>> +	pcie->pex_ctl_supply = devm_regulator_get(dev, "vddio-pex-ctl");
>>>>>> +	if (IS_ERR(pcie->pex_ctl_supply)) {
>>>>>> +		dev_err(dev, "Failed to get regulator: %ld\n",
>>>>>> +			PTR_ERR(pcie->pex_ctl_supply));
>>>>>> +		return PTR_ERR(pcie->pex_ctl_supply);
>>>>>> +	}
>>>>>> +
>>>>>> +	pcie->core_clk = devm_clk_get(dev, "core");
>>>>>> +	if (IS_ERR(pcie->core_clk)) {
>>>>>> +		dev_err(dev, "Failed to get core clock: %ld\n",
>>>>>> +			PTR_ERR(pcie->core_clk));
>>>>>> +		return PTR_ERR(pcie->core_clk);
>>>>>> +	}
>>>>>> +
>>>>>> +	pcie->appl_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>>>>>> +						      "appl");
>>>>>> +	if (!pcie->appl_res) {
>>>>>> +		dev_err(dev, "Failed to find \"appl\" region\n");
>>>>>> +		return PTR_ERR(pcie->appl_res);
>>>>>> +	}
>>>>>> +	pcie->appl_base = devm_ioremap_resource(dev, pcie->appl_res);
>>>>>> +	if (IS_ERR(pcie->appl_base))
>>>>>> +		return PTR_ERR(pcie->appl_base);
>>>>>> +
>>>>>> +	pcie->core_apb_rst = devm_reset_control_get(dev, "apb");
>>>>>> +	if (IS_ERR(pcie->core_apb_rst)) {
>>>>>> +		dev_err(dev, "Failed to get APB reset: %ld\n",
>>>>>> +			PTR_ERR(pcie->core_apb_rst));
>>>>>> +		return PTR_ERR(pcie->core_apb_rst);
>>>>>> +	}
>>>>>> +
>>>>>> +	phys = devm_kcalloc(dev, pcie->phy_count, sizeof(*phys), GFP_KERNEL);
>>>>>> +	if (!phys)
>>>>>> +		return PTR_ERR(phys);
>>>>>> +
>>>>>> +	for (i = 0; i < pcie->phy_count; i++) {
>>>>>> +		name = kasprintf(GFP_KERNEL, "p2u-%u", i);
>>>>>> +		if (!name) {
>>>>>> +			dev_err(dev, "Failed to create P2U string\n");
>>>>>> +			return -ENOMEM;
>>>>>> +		}
>>>>>> +		phys[i] = devm_phy_get(dev, name);
>>>>>> +		kfree(name);
>>>>>> +		if (IS_ERR(phys[i])) {
>>>>>> +			ret = PTR_ERR(phys[i]);
>>>>>> +			dev_err(dev, "Failed to get PHY: %d\n", ret);
>>>>>> +			return ret;
>>>>>> +		}
>>>>>> +	}
>>>>>> +
>>>>>> +	pcie->phys = phys;
>>>>>> +
>>>>>> +	dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
>>>>>> +	if (!dbi_res) {
>>>>>> +		dev_err(dev, "Failed to find \"dbi\" region\n");
>>>>>> +		return PTR_ERR(dbi_res);
>>>>>> +	}
>>>>>> +	pcie->dbi_res = dbi_res;
>>>>>> +
>>>>>> +	pci->dbi_base = devm_ioremap_resource(dev, dbi_res);
>>>>>> +	if (IS_ERR(pci->dbi_base))
>>>>>> +		return PTR_ERR(pci->dbi_base);
>>>>>> +
>>>>>> +	/* Tegra HW locates DBI2 at a fixed offset from DBI */
>>>>>> +	pci->dbi_base2 = pci->dbi_base + 0x1000;
>>>>>> +
>>>>>> +	atu_dma_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>>>>>> +						   "atu_dma");
>>>>>> +	if (!atu_dma_res) {
>>>>>> +		dev_err(dev, "Failed to find \"atu_dma\" region\n");
>>>>>> +		return PTR_ERR(atu_dma_res);
>>>>>> +	}
>>>>>> +	pcie->atu_dma_res = atu_dma_res;
>>>>>> +	pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);
>>>>>> +	if (IS_ERR(pci->atu_base))
>>>>>> +		return PTR_ERR(pci->atu_base);
>>>>>> +
>>>>>> +	pcie->core_rst = devm_reset_control_get(dev, "core");
>>>>>> +	if (IS_ERR(pcie->core_rst)) {
>>>>>> +		dev_err(dev, "Failed to get core reset: %ld\n",
>>>>>> +			PTR_ERR(pcie->core_rst));
>>>>>> +		return PTR_ERR(pcie->core_rst);
>>>>>> +	}
>>>>>> +
>>>>>> +	pp->irq = platform_get_irq_byname(pdev, "intr");
>>>>>> +	if (!pp->irq) {
>>>>>> +		dev_err(dev, "Failed to get \"intr\" interrupt\n");
>>>>>> +		return -ENODEV;
>>>>>> +	}
>>>>>> +
>>>>>> +	ret = devm_request_irq(dev, pp->irq, tegra_pcie_irq_handler,
>>>>>> +			       IRQF_SHARED, "tegra-pcie-intr", pcie);
>>>>>> +	if (ret) {
>>>>>> +		dev_err(dev, "Failed to request IRQ %d: %d\n", pp->irq, ret);
>>>>>> +		return ret;
>>>>>> +	}
>>>>>> +
>>>>>> +	pcie->bpmp = tegra_bpmp_get(dev);
>>>>>> +	if (IS_ERR(pcie->bpmp))
>>>>>> +		return PTR_ERR(pcie->bpmp);
>>>>>> +
>>>>>> +	platform_set_drvdata(pdev, pcie);
>>>>>> +
>>>>>> +	if (pcie->mode == DW_PCIE_RC_TYPE) {
>>>>>> +		ret = tegra_pcie_config_rp(pcie);
>>>>>> +		if (ret && ret != -ENOMEDIUM)
>>>>>> +			goto fail;
>>>>>> +		else
>>>>>> +			return 0;
>>>>>
>>>>> So if the link is not up we still go ahead and make probe
>>>>> succeed. What for ?
>>>> We may need root port to be available to support hot-plugging of
>>>> endpoint devices, so, we don't fail the probe.
>>>
>>> We need it or we don't. If you do support hotplugging of endpoint
>>> devices point me at the code, otherwise link up failure means
>>> failure to probe.
>> Currently hotplugging of endpoint is not supported, but it is one of
>> the use cases that we may add support for in future.
> 
> You should elaborate on this, I do not understand what you mean,
> either the root port(s) supports hotplug or it does not.
> 
>> But, why should we fail probe if link up doesn't happen? As such,
>> nothing went wrong in terms of root port initialization right?  I
>> checked other DWC based implementations and following are not failing
>> the probe pci-dra7xx.c, pcie-armada8k.c, pcie-artpec6.c, pcie-histb.c,
>> pcie-kirin.c, pcie-spear13xx.c, pci-exynos.c, pci-imx6.c,
>> pci-keystone.c, pci-layerscape.c
>>
>> Although following do fail the probe if link is not up.  pcie-qcom.c,
>> pcie-uniphier.c, pci-meson.c
>>
>> So, to me, it looks more like a choice we can make whether to fail the
>> probe or not and in this case we are choosing not to fail.
> 
> I disagree. I had an offline chat with Bjorn and whether link-up should
> fail the probe or not depends on whether the root port(s) is hotplug
> capable or not and this in turn relies on the root port "Slot
> implemented" bit in the PCI Express capabilities register.
> 
> It is a choice but it should be based on evidence.
> 
> Lorenzo
With Bjorn's latest comment on top of this, I think we are good not to fail
the probe here.

- Vidya Sagar
>

On Tue, Jul 23, 2019 at 08:14:08PM +0530, Vidya Sagar wrote:
> On 7/16/2019 4:52 PM, Lorenzo Pieralisi wrote:
> > On Sat, Jul 13, 2019 at 12:34:34PM +0530, Vidya Sagar wrote:
> > 
> > [...]
> > 
> > > > > > > +static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
> > > > > > > +					  bool enable)
> > > > > > > +{
> > > > > > > +	struct mrq_uphy_response resp;
> > > > > > > +	struct tegra_bpmp_message msg;
> > > > > > > +	struct mrq_uphy_request req;
> > > > > > > +	int err;
> > > > > > > +
> > > > > > > +	if (pcie->cid == 5)
> > > > > > > +		return 0;
> > > > > > 
> > > > > > What's wrong with cid == 5 ? Explain please.
> > > > > Controller with ID=5 doesn't need any programming to enable it which is
> > > > > done here through calling firmware API.
> > > > > 
> > > > > > 
> > > > > > > +	memset(&req, 0, sizeof(req));
> > > > > > > +	memset(&resp, 0, sizeof(resp));
> > > > > > > +
> > > > > > > +	req.cmd = CMD_UPHY_PCIE_CONTROLLER_STATE;
> > > > > > > +	req.controller_state.pcie_controller = pcie->cid;
> > > > > > > +	req.controller_state.enable = enable;
> > > > > > > +
> > > > > > > +	memset(&msg, 0, sizeof(msg));
> > > > > > > +	msg.mrq = MRQ_UPHY;
> > > > > > > +	msg.tx.data = &req;
> > > > > > > +	msg.tx.size = sizeof(req);
> > > > > > > +	msg.rx.data = &resp;
> > > > > > > +	msg.rx.size = sizeof(resp);
> > > > > > > +
> > > > > > > +	if (irqs_disabled())
> > > > > > 
> > > > > > Can you explain to me what this check is meant to achieve please ?
> > > > > Firmware interface provides different APIs to be called when there are
> > > > > no interrupts enabled in the system (noirq context) and otherwise
> > > > > hence checking that situation here and calling appropriate API.
> > > > 
> > > > That's what I am questioning. Being called from {suspend/resume}_noirq()
> > > > callbacks (if that's the code path this check caters for) does not mean
> > > > irqs_disabled() == true.
> > > Agree.
> > > Actually, I got a hint of having this check from the following.
> > > Both tegra_bpmp_transfer_atomic() and tegra_bpmp_transfer() are indirectly
> > > called by APIs registered with .master_xfer() and .master_xfer_atomic() hooks of
> > > struct i2c_algorithm and the decision to call which one of these is made using the
> > > following check in i2c-core.h file.
> > > static inline bool i2c_in_atomic_xfer_mode(void)
> > > {
> > > 	return system_state > SYSTEM_RUNNING && irqs_disabled();
> > > }
> > > I think I should use this condition as is IIUC.
> > > Please let me know if there are any concerns with this.
> > 
> > It is not a concern, it is just that I don't understand how this code
> > can be called with IRQs disabled, if you can give me an execution path I
> > am happy to leave the check there. On top of that, when called from
> > suspend NOIRQ context, it is likely to use the blocking API (because
> > IRQs aren't disabled at CPU level) behind which there is most certainly
> > an IRQ required to wake the thread up and if the IRQ in question was
> > disabled in the suspend NOIRQ phase this code is likely to deadlock.
> > 
> > I want to make sure we can justify adding this check, I do not
> > want to add it because we think it can be needed when it may not
> > be needed at all (and it gets copy and pasted over and over again
> > in other drivers).
> I had a discussion internally about this and the prescribed usage of these APIs
> seem to be that
> use tegra_bpmp_transfer() in .probe() and other paths where interrupts are
> enabled as this API needs interrupts to be enabled for its working.
> Use tegra_bpmp_transfer_atomic() surrounded by local_irq_save()/local_irq_restore()
> in other paths where interrupt servicing is disabled.

Why tegra_bpmp_transfer_atomic() needs IRQs to be disabled ? And why
is it needed in this piece of code where IRQs are _never_ disabled
at CPU level ?

IRQs are enabled when you call a suspend_noirq() callback, so the
blocking API can be used as long as the IRQ descriptor backing
the IRQ that will wake-up the blocked call is marked as
IRQF_NO_SUSPEND.

The problem is not IRQs enabled/disabled at CPU level, the problem is
the IRQ descriptor of the IRQ required to handle the blocking BPMP call,
mark it as IRQF_NO_SUSPEND and remove the tegra_bpmp_transfer_atomic()
call from this code (or please give me a concrete example pinpointing
why it is needed).

Thanks,
Lorenzo

> I'll go ahead and make next patch series with this if this looks fine to you.
> 
> > 
> > > > Actually, if tegra_bpmp_transfer() requires IRQs to be enabled you may
> > > > even end up in a situation where that blocking call does not wake up
> > > > because the IRQ in question was disabled in the NOIRQ suspend/resume
> > > > phase.
> > > > 
> > > > [...]
> > > > 
> > > > > > > +static int tegra_pcie_dw_probe(struct platform_device *pdev)
> > > > > > > +{
> > > > > > > +	const struct tegra_pcie_soc *data;
> > > > > > > +	struct device *dev = &pdev->dev;
> > > > > > > +	struct resource *atu_dma_res;
> > > > > > > +	struct tegra_pcie_dw *pcie;
> > > > > > > +	struct resource *dbi_res;
> > > > > > > +	struct pcie_port *pp;
> > > > > > > +	struct dw_pcie *pci;
> > > > > > > +	struct phy **phys;
> > > > > > > +	char *name;
> > > > > > > +	int ret;
> > > > > > > +	u32 i;
> > > > > > > +
> > > > > > > +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> > > > > > > +	if (!pcie)
> > > > > > > +		return -ENOMEM;
> > > > > > > +
> > > > > > > +	pci = &pcie->pci;
> > > > > > > +	pci->dev = &pdev->dev;
> > > > > > > +	pci->ops = &tegra_dw_pcie_ops;
> > > > > > > +	pp = &pci->pp;
> > > > > > > +	pcie->dev = &pdev->dev;
> > > > > > > +
> > > > > > > +	data = (struct tegra_pcie_soc *)of_device_get_match_data(dev);
> > > > > > > +	if (!data)
> > > > > > > +		return -EINVAL;
> > > > > > > +	pcie->mode = (enum dw_pcie_device_mode)data->mode;
> > > > > > > +
> > > > > > > +	ret = tegra_pcie_dw_parse_dt(pcie);
> > > > > > > +	if (ret < 0) {
> > > > > > > +		dev_err(dev, "Failed to parse device tree: %d\n", ret);
> > > > > > > +		return ret;
> > > > > > > +	}
> > > > > > > +
> > > > > > > +	pcie->pex_ctl_supply = devm_regulator_get(dev, "vddio-pex-ctl");
> > > > > > > +	if (IS_ERR(pcie->pex_ctl_supply)) {
> > > > > > > +		dev_err(dev, "Failed to get regulator: %ld\n",
> > > > > > > +			PTR_ERR(pcie->pex_ctl_supply));
> > > > > > > +		return PTR_ERR(pcie->pex_ctl_supply);
> > > > > > > +	}
> > > > > > > +
> > > > > > > +	pcie->core_clk = devm_clk_get(dev, "core");
> > > > > > > +	if (IS_ERR(pcie->core_clk)) {
> > > > > > > +		dev_err(dev, "Failed to get core clock: %ld\n",
> > > > > > > +			PTR_ERR(pcie->core_clk));
> > > > > > > +		return PTR_ERR(pcie->core_clk);
> > > > > > > +	}
> > > > > > > +
> > > > > > > +	pcie->appl_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > > > > > > +						      "appl");
> > > > > > > +	if (!pcie->appl_res) {
> > > > > > > +		dev_err(dev, "Failed to find \"appl\" region\n");
> > > > > > > +		return PTR_ERR(pcie->appl_res);
> > > > > > > +	}
> > > > > > > +	pcie->appl_base = devm_ioremap_resource(dev, pcie->appl_res);
> > > > > > > +	if (IS_ERR(pcie->appl_base))
> > > > > > > +		return PTR_ERR(pcie->appl_base);
> > > > > > > +
> > > > > > > +	pcie->core_apb_rst = devm_reset_control_get(dev, "apb");
> > > > > > > +	if (IS_ERR(pcie->core_apb_rst)) {
> > > > > > > +		dev_err(dev, "Failed to get APB reset: %ld\n",
> > > > > > > +			PTR_ERR(pcie->core_apb_rst));
> > > > > > > +		return PTR_ERR(pcie->core_apb_rst);
> > > > > > > +	}
> > > > > > > +
> > > > > > > +	phys = devm_kcalloc(dev, pcie->phy_count, sizeof(*phys), GFP_KERNEL);
> > > > > > > +	if (!phys)
> > > > > > > +		return PTR_ERR(phys);
> > > > > > > +
> > > > > > > +	for (i = 0; i < pcie->phy_count; i++) {
> > > > > > > +		name = kasprintf(GFP_KERNEL, "p2u-%u", i);
> > > > > > > +		if (!name) {
> > > > > > > +			dev_err(dev, "Failed to create P2U string\n");
> > > > > > > +			return -ENOMEM;
> > > > > > > +		}
> > > > > > > +		phys[i] = devm_phy_get(dev, name);
> > > > > > > +		kfree(name);
> > > > > > > +		if (IS_ERR(phys[i])) {
> > > > > > > +			ret = PTR_ERR(phys[i]);
> > > > > > > +			dev_err(dev, "Failed to get PHY: %d\n", ret);
> > > > > > > +			return ret;
> > > > > > > +		}
> > > > > > > +	}
> > > > > > > +
> > > > > > > +	pcie->phys = phys;
> > > > > > > +
> > > > > > > +	dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
> > > > > > > +	if (!dbi_res) {
> > > > > > > +		dev_err(dev, "Failed to find \"dbi\" region\n");
> > > > > > > +		return PTR_ERR(dbi_res);
> > > > > > > +	}
> > > > > > > +	pcie->dbi_res = dbi_res;
> > > > > > > +
> > > > > > > +	pci->dbi_base = devm_ioremap_resource(dev, dbi_res);
> > > > > > > +	if (IS_ERR(pci->dbi_base))
> > > > > > > +		return PTR_ERR(pci->dbi_base);
> > > > > > > +
> > > > > > > +	/* Tegra HW locates DBI2 at a fixed offset from DBI */
> > > > > > > +	pci->dbi_base2 = pci->dbi_base + 0x1000;
> > > > > > > +
> > > > > > > +	atu_dma_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > > > > > > +						   "atu_dma");
> > > > > > > +	if (!atu_dma_res) {
> > > > > > > +		dev_err(dev, "Failed to find \"atu_dma\" region\n");
> > > > > > > +		return PTR_ERR(atu_dma_res);
> > > > > > > +	}
> > > > > > > +	pcie->atu_dma_res = atu_dma_res;
> > > > > > > +	pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);
> > > > > > > +	if (IS_ERR(pci->atu_base))
> > > > > > > +		return PTR_ERR(pci->atu_base);
> > > > > > > +
> > > > > > > +	pcie->core_rst = devm_reset_control_get(dev, "core");
> > > > > > > +	if (IS_ERR(pcie->core_rst)) {
> > > > > > > +		dev_err(dev, "Failed to get core reset: %ld\n",
> > > > > > > +			PTR_ERR(pcie->core_rst));
> > > > > > > +		return PTR_ERR(pcie->core_rst);
> > > > > > > +	}
> > > > > > > +
> > > > > > > +	pp->irq = platform_get_irq_byname(pdev, "intr");
> > > > > > > +	if (!pp->irq) {
> > > > > > > +		dev_err(dev, "Failed to get \"intr\" interrupt\n");
> > > > > > > +		return -ENODEV;
> > > > > > > +	}
> > > > > > > +
> > > > > > > +	ret = devm_request_irq(dev, pp->irq, tegra_pcie_irq_handler,
> > > > > > > +			       IRQF_SHARED, "tegra-pcie-intr", pcie);
> > > > > > > +	if (ret) {
> > > > > > > +		dev_err(dev, "Failed to request IRQ %d: %d\n", pp->irq, ret);
> > > > > > > +		return ret;
> > > > > > > +	}
> > > > > > > +
> > > > > > > +	pcie->bpmp = tegra_bpmp_get(dev);
> > > > > > > +	if (IS_ERR(pcie->bpmp))
> > > > > > > +		return PTR_ERR(pcie->bpmp);
> > > > > > > +
> > > > > > > +	platform_set_drvdata(pdev, pcie);
> > > > > > > +
> > > > > > > +	if (pcie->mode == DW_PCIE_RC_TYPE) {
> > > > > > > +		ret = tegra_pcie_config_rp(pcie);
> > > > > > > +		if (ret && ret != -ENOMEDIUM)
> > > > > > > +			goto fail;
> > > > > > > +		else
> > > > > > > +			return 0;
> > > > > > 
> > > > > > So if the link is not up we still go ahead and make probe
> > > > > > succeed. What for ?
> > > > > We may need root port to be available to support hot-plugging of
> > > > > endpoint devices, so, we don't fail the probe.
> > > > 
> > > > We need it or we don't. If you do support hotplugging of endpoint
> > > > devices point me at the code, otherwise link up failure means
> > > > failure to probe.
> > > Currently hotplugging of endpoint is not supported, but it is one of
> > > the use cases that we may add support for in future.
> > 
> > You should elaborate on this, I do not understand what you mean,
> > either the root port(s) supports hotplug or it does not.
> > 
> > > But, why should we fail probe if link up doesn't happen? As such,
> > > nothing went wrong in terms of root port initialization right?  I
> > > checked other DWC based implementations and following are not failing
> > > the probe pci-dra7xx.c, pcie-armada8k.c, pcie-artpec6.c, pcie-histb.c,
> > > pcie-kirin.c, pcie-spear13xx.c, pci-exynos.c, pci-imx6.c,
> > > pci-keystone.c, pci-layerscape.c
> > > 
> > > Although following do fail the probe if link is not up.  pcie-qcom.c,
> > > pcie-uniphier.c, pci-meson.c
> > > 
> > > So, to me, it looks more like a choice we can make whether to fail the
> > > probe or not and in this case we are choosing not to fail.
> > 
> > I disagree. I had an offline chat with Bjorn and whether link-up should
> > fail the probe or not depends on whether the root port(s) is hotplug
> > capable or not and this in turn relies on the root port "Slot
> > implemented" bit in the PCI Express capabilities register.
> > 
> > It is a choice but it should be based on evidence.
> > 
> > Lorenzo
> With Bjorn's latest comment on top of this, I think we are good not to fail
> the probe here.
> 
> - Vidya Sagar
> > 
>

On 7/30/2019 9:19 PM, Lorenzo Pieralisi wrote:
> On Tue, Jul 23, 2019 at 08:14:08PM +0530, Vidya Sagar wrote:
>> On 7/16/2019 4:52 PM, Lorenzo Pieralisi wrote:
>>> On Sat, Jul 13, 2019 at 12:34:34PM +0530, Vidya Sagar wrote:
>>>
>>> [...]
>>>
>>>>>>>> +static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
>>>>>>>> +					  bool enable)
>>>>>>>> +{
>>>>>>>> +	struct mrq_uphy_response resp;
>>>>>>>> +	struct tegra_bpmp_message msg;
>>>>>>>> +	struct mrq_uphy_request req;
>>>>>>>> +	int err;
>>>>>>>> +
>>>>>>>> +	if (pcie->cid == 5)
>>>>>>>> +		return 0;
>>>>>>>
>>>>>>> What's wrong with cid == 5 ? Explain please.
>>>>>> Controller with ID=5 doesn't need any programming to enable it which is
>>>>>> done here through calling firmware API.
>>>>>>
>>>>>>>
>>>>>>>> +	memset(&req, 0, sizeof(req));
>>>>>>>> +	memset(&resp, 0, sizeof(resp));
>>>>>>>> +
>>>>>>>> +	req.cmd = CMD_UPHY_PCIE_CONTROLLER_STATE;
>>>>>>>> +	req.controller_state.pcie_controller = pcie->cid;
>>>>>>>> +	req.controller_state.enable = enable;
>>>>>>>> +
>>>>>>>> +	memset(&msg, 0, sizeof(msg));
>>>>>>>> +	msg.mrq = MRQ_UPHY;
>>>>>>>> +	msg.tx.data = &req;
>>>>>>>> +	msg.tx.size = sizeof(req);
>>>>>>>> +	msg.rx.data = &resp;
>>>>>>>> +	msg.rx.size = sizeof(resp);
>>>>>>>> +
>>>>>>>> +	if (irqs_disabled())
>>>>>>>
>>>>>>> Can you explain to me what this check is meant to achieve please ?
>>>>>> Firmware interface provides different APIs to be called when there are
>>>>>> no interrupts enabled in the system (noirq context) and otherwise
>>>>>> hence checking that situation here and calling appropriate API.
>>>>>
>>>>> That's what I am questioning. Being called from {suspend/resume}_noirq()
>>>>> callbacks (if that's the code path this check caters for) does not mean
>>>>> irqs_disabled() == true.
>>>> Agree.
>>>> Actually, I got a hint of having this check from the following.
>>>> Both tegra_bpmp_transfer_atomic() and tegra_bpmp_transfer() are indirectly
>>>> called by APIs registered with .master_xfer() and .master_xfer_atomic() hooks of
>>>> struct i2c_algorithm and the decision to call which one of these is made using the
>>>> following check in i2c-core.h file.
>>>> static inline bool i2c_in_atomic_xfer_mode(void)
>>>> {
>>>> 	return system_state > SYSTEM_RUNNING && irqs_disabled();
>>>> }
>>>> I think I should use this condition as is IIUC.
>>>> Please let me know if there are any concerns with this.
>>>
>>> It is not a concern, it is just that I don't understand how this code
>>> can be called with IRQs disabled, if you can give me an execution path I
>>> am happy to leave the check there. On top of that, when called from
>>> suspend NOIRQ context, it is likely to use the blocking API (because
>>> IRQs aren't disabled at CPU level) behind which there is most certainly
>>> an IRQ required to wake the thread up and if the IRQ in question was
>>> disabled in the suspend NOIRQ phase this code is likely to deadlock.
>>>
>>> I want to make sure we can justify adding this check, I do not
>>> want to add it because we think it can be needed when it may not
>>> be needed at all (and it gets copy and pasted over and over again
>>> in other drivers).
>> I had a discussion internally about this and the prescribed usage of these APIs
>> seem to be that
>> use tegra_bpmp_transfer() in .probe() and other paths where interrupts are
>> enabled as this API needs interrupts to be enabled for its working.
>> Use tegra_bpmp_transfer_atomic() surrounded by local_irq_save()/local_irq_restore()
>> in other paths where interrupt servicing is disabled.
> 
> Why tegra_bpmp_transfer_atomic() needs IRQs to be disabled ? And why
> is it needed in this piece of code where IRQs are _never_ disabled
> at CPU level ?
> 
> IRQs are enabled when you call a suspend_noirq() callback, so the
> blocking API can be used as long as the IRQ descriptor backing
> the IRQ that will wake-up the blocked call is marked as
> IRQF_NO_SUSPEND.
> 
> The problem is not IRQs enabled/disabled at CPU level, the problem is
> the IRQ descriptor of the IRQ required to handle the blocking BPMP call,
> mark it as IRQF_NO_SUSPEND and remove the tegra_bpmp_transfer_atomic()
> call from this code (or please give me a concrete example pinpointing
> why it is needed).
Ideally, using tegra_bpmp_transfer() alone in all paths (.probe() as well as .resume_noirq())
should have worked as the corresponding IRQ is already flagged as IRQF_NO_SUSPEND, but,
because of the way BPMP-FW driver in kernel making its interface available through .resume_early(),
tegra_bpmp_transfer() wasn't working as expected and I pushed a patch (CC'ing you) at
http://patchwork.ozlabs.org/patch/1140973/ to make it .resume_noirq() from .resume_early().
With that in place, we can just use tegra_bpmp_trasnfer().
I'll push a new patch with this change once my BPMP-FW driver patch is approved.

Thanks,
Vidya Sagar
> 
> Thanks,
> Lorenzo
> 
>> I'll go ahead and make next patch series with this if this looks fine to you.
>>
>>>
>>>>> Actually, if tegra_bpmp_transfer() requires IRQs to be enabled you may
>>>>> even end up in a situation where that blocking call does not wake up
>>>>> because the IRQ in question was disabled in the NOIRQ suspend/resume
>>>>> phase.
>>>>>
>>>>> [...]
>>>>>
>>>>>>>> +static int tegra_pcie_dw_probe(struct platform_device *pdev)
>>>>>>>> +{
>>>>>>>> +	const struct tegra_pcie_soc *data;
>>>>>>>> +	struct device *dev = &pdev->dev;
>>>>>>>> +	struct resource *atu_dma_res;
>>>>>>>> +	struct tegra_pcie_dw *pcie;
>>>>>>>> +	struct resource *dbi_res;
>>>>>>>> +	struct pcie_port *pp;
>>>>>>>> +	struct dw_pcie *pci;
>>>>>>>> +	struct phy **phys;
>>>>>>>> +	char *name;
>>>>>>>> +	int ret;
>>>>>>>> +	u32 i;
>>>>>>>> +
>>>>>>>> +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
>>>>>>>> +	if (!pcie)
>>>>>>>> +		return -ENOMEM;
>>>>>>>> +
>>>>>>>> +	pci = &pcie->pci;
>>>>>>>> +	pci->dev = &pdev->dev;
>>>>>>>> +	pci->ops = &tegra_dw_pcie_ops;
>>>>>>>> +	pp = &pci->pp;
>>>>>>>> +	pcie->dev = &pdev->dev;
>>>>>>>> +
>>>>>>>> +	data = (struct tegra_pcie_soc *)of_device_get_match_data(dev);
>>>>>>>> +	if (!data)
>>>>>>>> +		return -EINVAL;
>>>>>>>> +	pcie->mode = (enum dw_pcie_device_mode)data->mode;
>>>>>>>> +
>>>>>>>> +	ret = tegra_pcie_dw_parse_dt(pcie);
>>>>>>>> +	if (ret < 0) {
>>>>>>>> +		dev_err(dev, "Failed to parse device tree: %d\n", ret);
>>>>>>>> +		return ret;
>>>>>>>> +	}
>>>>>>>> +
>>>>>>>> +	pcie->pex_ctl_supply = devm_regulator_get(dev, "vddio-pex-ctl");
>>>>>>>> +	if (IS_ERR(pcie->pex_ctl_supply)) {
>>>>>>>> +		dev_err(dev, "Failed to get regulator: %ld\n",
>>>>>>>> +			PTR_ERR(pcie->pex_ctl_supply));
>>>>>>>> +		return PTR_ERR(pcie->pex_ctl_supply);
>>>>>>>> +	}
>>>>>>>> +
>>>>>>>> +	pcie->core_clk = devm_clk_get(dev, "core");
>>>>>>>> +	if (IS_ERR(pcie->core_clk)) {
>>>>>>>> +		dev_err(dev, "Failed to get core clock: %ld\n",
>>>>>>>> +			PTR_ERR(pcie->core_clk));
>>>>>>>> +		return PTR_ERR(pcie->core_clk);
>>>>>>>> +	}
>>>>>>>> +
>>>>>>>> +	pcie->appl_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>>>>>>>> +						      "appl");
>>>>>>>> +	if (!pcie->appl_res) {
>>>>>>>> +		dev_err(dev, "Failed to find \"appl\" region\n");
>>>>>>>> +		return PTR_ERR(pcie->appl_res);
>>>>>>>> +	}
>>>>>>>> +	pcie->appl_base = devm_ioremap_resource(dev, pcie->appl_res);
>>>>>>>> +	if (IS_ERR(pcie->appl_base))
>>>>>>>> +		return PTR_ERR(pcie->appl_base);
>>>>>>>> +
>>>>>>>> +	pcie->core_apb_rst = devm_reset_control_get(dev, "apb");
>>>>>>>> +	if (IS_ERR(pcie->core_apb_rst)) {
>>>>>>>> +		dev_err(dev, "Failed to get APB reset: %ld\n",
>>>>>>>> +			PTR_ERR(pcie->core_apb_rst));
>>>>>>>> +		return PTR_ERR(pcie->core_apb_rst);
>>>>>>>> +	}
>>>>>>>> +
>>>>>>>> +	phys = devm_kcalloc(dev, pcie->phy_count, sizeof(*phys), GFP_KERNEL);
>>>>>>>> +	if (!phys)
>>>>>>>> +		return PTR_ERR(phys);
>>>>>>>> +
>>>>>>>> +	for (i = 0; i < pcie->phy_count; i++) {
>>>>>>>> +		name = kasprintf(GFP_KERNEL, "p2u-%u", i);
>>>>>>>> +		if (!name) {
>>>>>>>> +			dev_err(dev, "Failed to create P2U string\n");
>>>>>>>> +			return -ENOMEM;
>>>>>>>> +		}
>>>>>>>> +		phys[i] = devm_phy_get(dev, name);
>>>>>>>> +		kfree(name);
>>>>>>>> +		if (IS_ERR(phys[i])) {
>>>>>>>> +			ret = PTR_ERR(phys[i]);
>>>>>>>> +			dev_err(dev, "Failed to get PHY: %d\n", ret);
>>>>>>>> +			return ret;
>>>>>>>> +		}
>>>>>>>> +	}
>>>>>>>> +
>>>>>>>> +	pcie->phys = phys;
>>>>>>>> +
>>>>>>>> +	dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
>>>>>>>> +	if (!dbi_res) {
>>>>>>>> +		dev_err(dev, "Failed to find \"dbi\" region\n");
>>>>>>>> +		return PTR_ERR(dbi_res);
>>>>>>>> +	}
>>>>>>>> +	pcie->dbi_res = dbi_res;
>>>>>>>> +
>>>>>>>> +	pci->dbi_base = devm_ioremap_resource(dev, dbi_res);
>>>>>>>> +	if (IS_ERR(pci->dbi_base))
>>>>>>>> +		return PTR_ERR(pci->dbi_base);
>>>>>>>> +
>>>>>>>> +	/* Tegra HW locates DBI2 at a fixed offset from DBI */
>>>>>>>> +	pci->dbi_base2 = pci->dbi_base + 0x1000;
>>>>>>>> +
>>>>>>>> +	atu_dma_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>>>>>>>> +						   "atu_dma");
>>>>>>>> +	if (!atu_dma_res) {
>>>>>>>> +		dev_err(dev, "Failed to find \"atu_dma\" region\n");
>>>>>>>> +		return PTR_ERR(atu_dma_res);
>>>>>>>> +	}
>>>>>>>> +	pcie->atu_dma_res = atu_dma_res;
>>>>>>>> +	pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);
>>>>>>>> +	if (IS_ERR(pci->atu_base))
>>>>>>>> +		return PTR_ERR(pci->atu_base);
>>>>>>>> +
>>>>>>>> +	pcie->core_rst = devm_reset_control_get(dev, "core");
>>>>>>>> +	if (IS_ERR(pcie->core_rst)) {
>>>>>>>> +		dev_err(dev, "Failed to get core reset: %ld\n",
>>>>>>>> +			PTR_ERR(pcie->core_rst));
>>>>>>>> +		return PTR_ERR(pcie->core_rst);
>>>>>>>> +	}
>>>>>>>> +
>>>>>>>> +	pp->irq = platform_get_irq_byname(pdev, "intr");
>>>>>>>> +	if (!pp->irq) {
>>>>>>>> +		dev_err(dev, "Failed to get \"intr\" interrupt\n");
>>>>>>>> +		return -ENODEV;
>>>>>>>> +	}
>>>>>>>> +
>>>>>>>> +	ret = devm_request_irq(dev, pp->irq, tegra_pcie_irq_handler,
>>>>>>>> +			       IRQF_SHARED, "tegra-pcie-intr", pcie);
>>>>>>>> +	if (ret) {
>>>>>>>> +		dev_err(dev, "Failed to request IRQ %d: %d\n", pp->irq, ret);
>>>>>>>> +		return ret;
>>>>>>>> +	}
>>>>>>>> +
>>>>>>>> +	pcie->bpmp = tegra_bpmp_get(dev);
>>>>>>>> +	if (IS_ERR(pcie->bpmp))
>>>>>>>> +		return PTR_ERR(pcie->bpmp);
>>>>>>>> +
>>>>>>>> +	platform_set_drvdata(pdev, pcie);
>>>>>>>> +
>>>>>>>> +	if (pcie->mode == DW_PCIE_RC_TYPE) {
>>>>>>>> +		ret = tegra_pcie_config_rp(pcie);
>>>>>>>> +		if (ret && ret != -ENOMEDIUM)
>>>>>>>> +			goto fail;
>>>>>>>> +		else
>>>>>>>> +			return 0;
>>>>>>>
>>>>>>> So if the link is not up we still go ahead and make probe
>>>>>>> succeed. What for ?
>>>>>> We may need root port to be available to support hot-plugging of
>>>>>> endpoint devices, so, we don't fail the probe.
>>>>>
>>>>> We need it or we don't. If you do support hotplugging of endpoint
>>>>> devices point me at the code, otherwise link up failure means
>>>>> failure to probe.
>>>> Currently hotplugging of endpoint is not supported, but it is one of
>>>> the use cases that we may add support for in future.
>>>
>>> You should elaborate on this, I do not understand what you mean,
>>> either the root port(s) supports hotplug or it does not.
>>>
>>>> But, why should we fail probe if link up doesn't happen? As such,
>>>> nothing went wrong in terms of root port initialization right?  I
>>>> checked other DWC based implementations and following are not failing
>>>> the probe pci-dra7xx.c, pcie-armada8k.c, pcie-artpec6.c, pcie-histb.c,
>>>> pcie-kirin.c, pcie-spear13xx.c, pci-exynos.c, pci-imx6.c,
>>>> pci-keystone.c, pci-layerscape.c
>>>>
>>>> Although following do fail the probe if link is not up.  pcie-qcom.c,
>>>> pcie-uniphier.c, pci-meson.c
>>>>
>>>> So, to me, it looks more like a choice we can make whether to fail the
>>>> probe or not and in this case we are choosing not to fail.
>>>
>>> I disagree. I had an offline chat with Bjorn and whether link-up should
>>> fail the probe or not depends on whether the root port(s) is hotplug
>>> capable or not and this in turn relies on the root port "Slot
>>> implemented" bit in the PCI Express capabilities register.
>>>
>>> It is a choice but it should be based on evidence.
>>>
>>> Lorenzo
>> With Bjorn's latest comment on top of this, I think we are good not to fail
>> the probe here.
>>
>> - Vidya Sagar
>>>
>>

On Fri, Aug 02, 2019 at 05:36:43PM +0530, Vidya Sagar wrote:
> On 7/30/2019 9:19 PM, Lorenzo Pieralisi wrote:
> > On Tue, Jul 23, 2019 at 08:14:08PM +0530, Vidya Sagar wrote:
> > > On 7/16/2019 4:52 PM, Lorenzo Pieralisi wrote:
> > > > On Sat, Jul 13, 2019 at 12:34:34PM +0530, Vidya Sagar wrote:
> > > > 
> > > > [...]
> > > > 
> > > > > > > > > +static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
> > > > > > > > > +					  bool enable)
> > > > > > > > > +{
> > > > > > > > > +	struct mrq_uphy_response resp;
> > > > > > > > > +	struct tegra_bpmp_message msg;
> > > > > > > > > +	struct mrq_uphy_request req;
> > > > > > > > > +	int err;
> > > > > > > > > +
> > > > > > > > > +	if (pcie->cid == 5)
> > > > > > > > > +		return 0;
> > > > > > > > 
> > > > > > > > What's wrong with cid == 5 ? Explain please.
> > > > > > > Controller with ID=5 doesn't need any programming to enable it which is
> > > > > > > done here through calling firmware API.
> > > > > > > 
> > > > > > > > 
> > > > > > > > > +	memset(&req, 0, sizeof(req));
> > > > > > > > > +	memset(&resp, 0, sizeof(resp));
> > > > > > > > > +
> > > > > > > > > +	req.cmd = CMD_UPHY_PCIE_CONTROLLER_STATE;
> > > > > > > > > +	req.controller_state.pcie_controller = pcie->cid;
> > > > > > > > > +	req.controller_state.enable = enable;
> > > > > > > > > +
> > > > > > > > > +	memset(&msg, 0, sizeof(msg));
> > > > > > > > > +	msg.mrq = MRQ_UPHY;
> > > > > > > > > +	msg.tx.data = &req;
> > > > > > > > > +	msg.tx.size = sizeof(req);
> > > > > > > > > +	msg.rx.data = &resp;
> > > > > > > > > +	msg.rx.size = sizeof(resp);
> > > > > > > > > +
> > > > > > > > > +	if (irqs_disabled())
> > > > > > > > 
> > > > > > > > Can you explain to me what this check is meant to achieve please ?
> > > > > > > Firmware interface provides different APIs to be called when there are
> > > > > > > no interrupts enabled in the system (noirq context) and otherwise
> > > > > > > hence checking that situation here and calling appropriate API.
> > > > > > 
> > > > > > That's what I am questioning. Being called from {suspend/resume}_noirq()
> > > > > > callbacks (if that's the code path this check caters for) does not mean
> > > > > > irqs_disabled() == true.
> > > > > Agree.
> > > > > Actually, I got a hint of having this check from the following.
> > > > > Both tegra_bpmp_transfer_atomic() and tegra_bpmp_transfer() are indirectly
> > > > > called by APIs registered with .master_xfer() and .master_xfer_atomic() hooks of
> > > > > struct i2c_algorithm and the decision to call which one of these is made using the
> > > > > following check in i2c-core.h file.
> > > > > static inline bool i2c_in_atomic_xfer_mode(void)
> > > > > {
> > > > > 	return system_state > SYSTEM_RUNNING && irqs_disabled();
> > > > > }
> > > > > I think I should use this condition as is IIUC.
> > > > > Please let me know if there are any concerns with this.
> > > > 
> > > > It is not a concern, it is just that I don't understand how this code
> > > > can be called with IRQs disabled, if you can give me an execution path I
> > > > am happy to leave the check there. On top of that, when called from
> > > > suspend NOIRQ context, it is likely to use the blocking API (because
> > > > IRQs aren't disabled at CPU level) behind which there is most certainly
> > > > an IRQ required to wake the thread up and if the IRQ in question was
> > > > disabled in the suspend NOIRQ phase this code is likely to deadlock.
> > > > 
> > > > I want to make sure we can justify adding this check, I do not
> > > > want to add it because we think it can be needed when it may not
> > > > be needed at all (and it gets copy and pasted over and over again
> > > > in other drivers).
> > > I had a discussion internally about this and the prescribed usage of these APIs
> > > seem to be that
> > > use tegra_bpmp_transfer() in .probe() and other paths where interrupts are
> > > enabled as this API needs interrupts to be enabled for its working.
> > > Use tegra_bpmp_transfer_atomic() surrounded by local_irq_save()/local_irq_restore()
> > > in other paths where interrupt servicing is disabled.
> > 
> > Why tegra_bpmp_transfer_atomic() needs IRQs to be disabled ? And why
> > is it needed in this piece of code where IRQs are _never_ disabled
> > at CPU level ?
> > 
> > IRQs are enabled when you call a suspend_noirq() callback, so the
> > blocking API can be used as long as the IRQ descriptor backing
> > the IRQ that will wake-up the blocked call is marked as
> > IRQF_NO_SUSPEND.
> > 
> > The problem is not IRQs enabled/disabled at CPU level, the problem is
> > the IRQ descriptor of the IRQ required to handle the blocking BPMP call,
> > mark it as IRQF_NO_SUSPEND and remove the tegra_bpmp_transfer_atomic()
> > call from this code (or please give me a concrete example pinpointing
> > why it is needed).
> Ideally, using tegra_bpmp_transfer() alone in all paths (.probe() as
> well as .resume_noirq()) should have worked as the corresponding IRQ
> is already flagged as IRQF_NO_SUSPEND, but, because of the way BPMP-FW
> driver in kernel making its interface available through
> .resume_early(), tegra_bpmp_transfer() wasn't working as expected and
> I pushed a patch (CC'ing you) at
> http://patchwork.ozlabs.org/patch/1140973/ to make it .resume_noirq()
> from .resume_early().  With that in place, we can just use
> tegra_bpmp_trasnfer().  I'll push a new patch with this change once my
> BPMP-FW driver patch is approved.

Does this leave you with a resume_noirq() callbacks ordering issue to
sort out ?

a.k.a How will you guarantee that the BPMP will resume before the host
bridge ?

Thanks,
Lorenzo

> Thanks,
> Vidya Sagar
> > 
> > Thanks,
> > Lorenzo
> > 
> > > I'll go ahead and make next patch series with this if this looks fine to you.
> > > 
> > > > 
> > > > > > Actually, if tegra_bpmp_transfer() requires IRQs to be enabled you may
> > > > > > even end up in a situation where that blocking call does not wake up
> > > > > > because the IRQ in question was disabled in the NOIRQ suspend/resume
> > > > > > phase.
> > > > > > 
> > > > > > [...]
> > > > > > 
> > > > > > > > > +static int tegra_pcie_dw_probe(struct platform_device *pdev)
> > > > > > > > > +{
> > > > > > > > > +	const struct tegra_pcie_soc *data;
> > > > > > > > > +	struct device *dev = &pdev->dev;
> > > > > > > > > +	struct resource *atu_dma_res;
> > > > > > > > > +	struct tegra_pcie_dw *pcie;
> > > > > > > > > +	struct resource *dbi_res;
> > > > > > > > > +	struct pcie_port *pp;
> > > > > > > > > +	struct dw_pcie *pci;
> > > > > > > > > +	struct phy **phys;
> > > > > > > > > +	char *name;
> > > > > > > > > +	int ret;
> > > > > > > > > +	u32 i;
> > > > > > > > > +
> > > > > > > > > +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> > > > > > > > > +	if (!pcie)
> > > > > > > > > +		return -ENOMEM;
> > > > > > > > > +
> > > > > > > > > +	pci = &pcie->pci;
> > > > > > > > > +	pci->dev = &pdev->dev;
> > > > > > > > > +	pci->ops = &tegra_dw_pcie_ops;
> > > > > > > > > +	pp = &pci->pp;
> > > > > > > > > +	pcie->dev = &pdev->dev;
> > > > > > > > > +
> > > > > > > > > +	data = (struct tegra_pcie_soc *)of_device_get_match_data(dev);
> > > > > > > > > +	if (!data)
> > > > > > > > > +		return -EINVAL;
> > > > > > > > > +	pcie->mode = (enum dw_pcie_device_mode)data->mode;
> > > > > > > > > +
> > > > > > > > > +	ret = tegra_pcie_dw_parse_dt(pcie);
> > > > > > > > > +	if (ret < 0) {
> > > > > > > > > +		dev_err(dev, "Failed to parse device tree: %d\n", ret);
> > > > > > > > > +		return ret;
> > > > > > > > > +	}
> > > > > > > > > +
> > > > > > > > > +	pcie->pex_ctl_supply = devm_regulator_get(dev, "vddio-pex-ctl");
> > > > > > > > > +	if (IS_ERR(pcie->pex_ctl_supply)) {
> > > > > > > > > +		dev_err(dev, "Failed to get regulator: %ld\n",
> > > > > > > > > +			PTR_ERR(pcie->pex_ctl_supply));
> > > > > > > > > +		return PTR_ERR(pcie->pex_ctl_supply);
> > > > > > > > > +	}
> > > > > > > > > +
> > > > > > > > > +	pcie->core_clk = devm_clk_get(dev, "core");
> > > > > > > > > +	if (IS_ERR(pcie->core_clk)) {
> > > > > > > > > +		dev_err(dev, "Failed to get core clock: %ld\n",
> > > > > > > > > +			PTR_ERR(pcie->core_clk));
> > > > > > > > > +		return PTR_ERR(pcie->core_clk);
> > > > > > > > > +	}
> > > > > > > > > +
> > > > > > > > > +	pcie->appl_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > > > > > > > > +						      "appl");
> > > > > > > > > +	if (!pcie->appl_res) {
> > > > > > > > > +		dev_err(dev, "Failed to find \"appl\" region\n");
> > > > > > > > > +		return PTR_ERR(pcie->appl_res);
> > > > > > > > > +	}
> > > > > > > > > +	pcie->appl_base = devm_ioremap_resource(dev, pcie->appl_res);
> > > > > > > > > +	if (IS_ERR(pcie->appl_base))
> > > > > > > > > +		return PTR_ERR(pcie->appl_base);
> > > > > > > > > +
> > > > > > > > > +	pcie->core_apb_rst = devm_reset_control_get(dev, "apb");
> > > > > > > > > +	if (IS_ERR(pcie->core_apb_rst)) {
> > > > > > > > > +		dev_err(dev, "Failed to get APB reset: %ld\n",
> > > > > > > > > +			PTR_ERR(pcie->core_apb_rst));
> > > > > > > > > +		return PTR_ERR(pcie->core_apb_rst);
> > > > > > > > > +	}
> > > > > > > > > +
> > > > > > > > > +	phys = devm_kcalloc(dev, pcie->phy_count, sizeof(*phys), GFP_KERNEL);
> > > > > > > > > +	if (!phys)
> > > > > > > > > +		return PTR_ERR(phys);
> > > > > > > > > +
> > > > > > > > > +	for (i = 0; i < pcie->phy_count; i++) {
> > > > > > > > > +		name = kasprintf(GFP_KERNEL, "p2u-%u", i);
> > > > > > > > > +		if (!name) {
> > > > > > > > > +			dev_err(dev, "Failed to create P2U string\n");
> > > > > > > > > +			return -ENOMEM;
> > > > > > > > > +		}
> > > > > > > > > +		phys[i] = devm_phy_get(dev, name);
> > > > > > > > > +		kfree(name);
> > > > > > > > > +		if (IS_ERR(phys[i])) {
> > > > > > > > > +			ret = PTR_ERR(phys[i]);
> > > > > > > > > +			dev_err(dev, "Failed to get PHY: %d\n", ret);
> > > > > > > > > +			return ret;
> > > > > > > > > +		}
> > > > > > > > > +	}
> > > > > > > > > +
> > > > > > > > > +	pcie->phys = phys;
> > > > > > > > > +
> > > > > > > > > +	dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
> > > > > > > > > +	if (!dbi_res) {
> > > > > > > > > +		dev_err(dev, "Failed to find \"dbi\" region\n");
> > > > > > > > > +		return PTR_ERR(dbi_res);
> > > > > > > > > +	}
> > > > > > > > > +	pcie->dbi_res = dbi_res;
> > > > > > > > > +
> > > > > > > > > +	pci->dbi_base = devm_ioremap_resource(dev, dbi_res);
> > > > > > > > > +	if (IS_ERR(pci->dbi_base))
> > > > > > > > > +		return PTR_ERR(pci->dbi_base);
> > > > > > > > > +
> > > > > > > > > +	/* Tegra HW locates DBI2 at a fixed offset from DBI */
> > > > > > > > > +	pci->dbi_base2 = pci->dbi_base + 0x1000;
> > > > > > > > > +
> > > > > > > > > +	atu_dma_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > > > > > > > > +						   "atu_dma");
> > > > > > > > > +	if (!atu_dma_res) {
> > > > > > > > > +		dev_err(dev, "Failed to find \"atu_dma\" region\n");
> > > > > > > > > +		return PTR_ERR(atu_dma_res);
> > > > > > > > > +	}
> > > > > > > > > +	pcie->atu_dma_res = atu_dma_res;
> > > > > > > > > +	pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);
> > > > > > > > > +	if (IS_ERR(pci->atu_base))
> > > > > > > > > +		return PTR_ERR(pci->atu_base);
> > > > > > > > > +
> > > > > > > > > +	pcie->core_rst = devm_reset_control_get(dev, "core");
> > > > > > > > > +	if (IS_ERR(pcie->core_rst)) {
> > > > > > > > > +		dev_err(dev, "Failed to get core reset: %ld\n",
> > > > > > > > > +			PTR_ERR(pcie->core_rst));
> > > > > > > > > +		return PTR_ERR(pcie->core_rst);
> > > > > > > > > +	}
> > > > > > > > > +
> > > > > > > > > +	pp->irq = platform_get_irq_byname(pdev, "intr");
> > > > > > > > > +	if (!pp->irq) {
> > > > > > > > > +		dev_err(dev, "Failed to get \"intr\" interrupt\n");
> > > > > > > > > +		return -ENODEV;
> > > > > > > > > +	}
> > > > > > > > > +
> > > > > > > > > +	ret = devm_request_irq(dev, pp->irq, tegra_pcie_irq_handler,
> > > > > > > > > +			       IRQF_SHARED, "tegra-pcie-intr", pcie);
> > > > > > > > > +	if (ret) {
> > > > > > > > > +		dev_err(dev, "Failed to request IRQ %d: %d\n", pp->irq, ret);
> > > > > > > > > +		return ret;
> > > > > > > > > +	}
> > > > > > > > > +
> > > > > > > > > +	pcie->bpmp = tegra_bpmp_get(dev);
> > > > > > > > > +	if (IS_ERR(pcie->bpmp))
> > > > > > > > > +		return PTR_ERR(pcie->bpmp);
> > > > > > > > > +
> > > > > > > > > +	platform_set_drvdata(pdev, pcie);
> > > > > > > > > +
> > > > > > > > > +	if (pcie->mode == DW_PCIE_RC_TYPE) {
> > > > > > > > > +		ret = tegra_pcie_config_rp(pcie);
> > > > > > > > > +		if (ret && ret != -ENOMEDIUM)
> > > > > > > > > +			goto fail;
> > > > > > > > > +		else
> > > > > > > > > +			return 0;
> > > > > > > > 
> > > > > > > > So if the link is not up we still go ahead and make probe
> > > > > > > > succeed. What for ?
> > > > > > > We may need root port to be available to support hot-plugging of
> > > > > > > endpoint devices, so, we don't fail the probe.
> > > > > > 
> > > > > > We need it or we don't. If you do support hotplugging of endpoint
> > > > > > devices point me at the code, otherwise link up failure means
> > > > > > failure to probe.
> > > > > Currently hotplugging of endpoint is not supported, but it is one of
> > > > > the use cases that we may add support for in future.
> > > > 
> > > > You should elaborate on this, I do not understand what you mean,
> > > > either the root port(s) supports hotplug or it does not.
> > > > 
> > > > > But, why should we fail probe if link up doesn't happen? As such,
> > > > > nothing went wrong in terms of root port initialization right?  I
> > > > > checked other DWC based implementations and following are not failing
> > > > > the probe pci-dra7xx.c, pcie-armada8k.c, pcie-artpec6.c, pcie-histb.c,
> > > > > pcie-kirin.c, pcie-spear13xx.c, pci-exynos.c, pci-imx6.c,
> > > > > pci-keystone.c, pci-layerscape.c
> > > > > 
> > > > > Although following do fail the probe if link is not up.  pcie-qcom.c,
> > > > > pcie-uniphier.c, pci-meson.c
> > > > > 
> > > > > So, to me, it looks more like a choice we can make whether to fail the
> > > > > probe or not and in this case we are choosing not to fail.
> > > > 
> > > > I disagree. I had an offline chat with Bjorn and whether link-up should
> > > > fail the probe or not depends on whether the root port(s) is hotplug
> > > > capable or not and this in turn relies on the root port "Slot
> > > > implemented" bit in the PCI Express capabilities register.
> > > > 
> > > > It is a choice but it should be based on evidence.
> > > > 
> > > > Lorenzo
> > > With Bjorn's latest comment on top of this, I think we are good not to fail
> > > the probe here.
> > > 
> > > - Vidya Sagar
> > > > 
> > > 
>

On 8/5/2019 7:31 PM, Lorenzo Pieralisi wrote:
> On Fri, Aug 02, 2019 at 05:36:43PM +0530, Vidya Sagar wrote:
>> On 7/30/2019 9:19 PM, Lorenzo Pieralisi wrote:
>>> On Tue, Jul 23, 2019 at 08:14:08PM +0530, Vidya Sagar wrote:
>>>> On 7/16/2019 4:52 PM, Lorenzo Pieralisi wrote:
>>>>> On Sat, Jul 13, 2019 at 12:34:34PM +0530, Vidya Sagar wrote:
>>>>>
>>>>> [...]
>>>>>
>>>>>>>>>> +static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
>>>>>>>>>> +					  bool enable)
>>>>>>>>>> +{
>>>>>>>>>> +	struct mrq_uphy_response resp;
>>>>>>>>>> +	struct tegra_bpmp_message msg;
>>>>>>>>>> +	struct mrq_uphy_request req;
>>>>>>>>>> +	int err;
>>>>>>>>>> +
>>>>>>>>>> +	if (pcie->cid == 5)
>>>>>>>>>> +		return 0;
>>>>>>>>>
>>>>>>>>> What's wrong with cid == 5 ? Explain please.
>>>>>>>> Controller with ID=5 doesn't need any programming to enable it which is
>>>>>>>> done here through calling firmware API.
>>>>>>>>
>>>>>>>>>
>>>>>>>>>> +	memset(&req, 0, sizeof(req));
>>>>>>>>>> +	memset(&resp, 0, sizeof(resp));
>>>>>>>>>> +
>>>>>>>>>> +	req.cmd = CMD_UPHY_PCIE_CONTROLLER_STATE;
>>>>>>>>>> +	req.controller_state.pcie_controller = pcie->cid;
>>>>>>>>>> +	req.controller_state.enable = enable;
>>>>>>>>>> +
>>>>>>>>>> +	memset(&msg, 0, sizeof(msg));
>>>>>>>>>> +	msg.mrq = MRQ_UPHY;
>>>>>>>>>> +	msg.tx.data = &req;
>>>>>>>>>> +	msg.tx.size = sizeof(req);
>>>>>>>>>> +	msg.rx.data = &resp;
>>>>>>>>>> +	msg.rx.size = sizeof(resp);
>>>>>>>>>> +
>>>>>>>>>> +	if (irqs_disabled())
>>>>>>>>>
>>>>>>>>> Can you explain to me what this check is meant to achieve please ?
>>>>>>>> Firmware interface provides different APIs to be called when there are
>>>>>>>> no interrupts enabled in the system (noirq context) and otherwise
>>>>>>>> hence checking that situation here and calling appropriate API.
>>>>>>>
>>>>>>> That's what I am questioning. Being called from {suspend/resume}_noirq()
>>>>>>> callbacks (if that's the code path this check caters for) does not mean
>>>>>>> irqs_disabled() == true.
>>>>>> Agree.
>>>>>> Actually, I got a hint of having this check from the following.
>>>>>> Both tegra_bpmp_transfer_atomic() and tegra_bpmp_transfer() are indirectly
>>>>>> called by APIs registered with .master_xfer() and .master_xfer_atomic() hooks of
>>>>>> struct i2c_algorithm and the decision to call which one of these is made using the
>>>>>> following check in i2c-core.h file.
>>>>>> static inline bool i2c_in_atomic_xfer_mode(void)
>>>>>> {
>>>>>> 	return system_state > SYSTEM_RUNNING && irqs_disabled();
>>>>>> }
>>>>>> I think I should use this condition as is IIUC.
>>>>>> Please let me know if there are any concerns with this.
>>>>>
>>>>> It is not a concern, it is just that I don't understand how this code
>>>>> can be called with IRQs disabled, if you can give me an execution path I
>>>>> am happy to leave the check there. On top of that, when called from
>>>>> suspend NOIRQ context, it is likely to use the blocking API (because
>>>>> IRQs aren't disabled at CPU level) behind which there is most certainly
>>>>> an IRQ required to wake the thread up and if the IRQ in question was
>>>>> disabled in the suspend NOIRQ phase this code is likely to deadlock.
>>>>>
>>>>> I want to make sure we can justify adding this check, I do not
>>>>> want to add it because we think it can be needed when it may not
>>>>> be needed at all (and it gets copy and pasted over and over again
>>>>> in other drivers).
>>>> I had a discussion internally about this and the prescribed usage of these APIs
>>>> seem to be that
>>>> use tegra_bpmp_transfer() in .probe() and other paths where interrupts are
>>>> enabled as this API needs interrupts to be enabled for its working.
>>>> Use tegra_bpmp_transfer_atomic() surrounded by local_irq_save()/local_irq_restore()
>>>> in other paths where interrupt servicing is disabled.
>>>
>>> Why tegra_bpmp_transfer_atomic() needs IRQs to be disabled ? And why
>>> is it needed in this piece of code where IRQs are _never_ disabled
>>> at CPU level ?
>>>
>>> IRQs are enabled when you call a suspend_noirq() callback, so the
>>> blocking API can be used as long as the IRQ descriptor backing
>>> the IRQ that will wake-up the blocked call is marked as
>>> IRQF_NO_SUSPEND.
>>>
>>> The problem is not IRQs enabled/disabled at CPU level, the problem is
>>> the IRQ descriptor of the IRQ required to handle the blocking BPMP call,
>>> mark it as IRQF_NO_SUSPEND and remove the tegra_bpmp_transfer_atomic()
>>> call from this code (or please give me a concrete example pinpointing
>>> why it is needed).
>> Ideally, using tegra_bpmp_transfer() alone in all paths (.probe() as
>> well as .resume_noirq()) should have worked as the corresponding IRQ
>> is already flagged as IRQF_NO_SUSPEND, but, because of the way BPMP-FW
>> driver in kernel making its interface available through
>> .resume_early(), tegra_bpmp_transfer() wasn't working as expected and
>> I pushed a patch (CC'ing you) at
>> http://patchwork.ozlabs.org/patch/1140973/ to make it .resume_noirq()
>> from .resume_early().  With that in place, we can just use
>> tegra_bpmp_trasnfer().  I'll push a new patch with this change once my
>> BPMP-FW driver patch is approved.
> 
> Does this leave you with a resume_noirq() callbacks ordering issue to
> sort out ?
Not really.

> 
> a.k.a How will you guarantee that the BPMP will resume before the host
> bridge ?
It is already taken care of in the following way.
PCIe controller's device-tree node has an entry with a phandle of BPMP-FW's node
to get a handle of it and PCIe driver uses tegra_bpmp_get() API for that.
This API returns -EPROBE_DEFER if BPMP-FW's driver is not ready yet, which guarantees
that PCIe driver gets loaded only after BPMP-FW's driver and this order is followed
during noirq phase also.

> 
> Thanks,
> Lorenzo
> 
>> Thanks,
>> Vidya Sagar
>>>
>>> Thanks,
>>> Lorenzo
>>>
>>>> I'll go ahead and make next patch series with this if this looks fine to you.
>>>>
>>>>>
>>>>>>> Actually, if tegra_bpmp_transfer() requires IRQs to be enabled you may
>>>>>>> even end up in a situation where that blocking call does not wake up
>>>>>>> because the IRQ in question was disabled in the NOIRQ suspend/resume
>>>>>>> phase.
>>>>>>>
>>>>>>> [...]
>>>>>>>
>>>>>>>>>> +static int tegra_pcie_dw_probe(struct platform_device *pdev)
>>>>>>>>>> +{
>>>>>>>>>> +	const struct tegra_pcie_soc *data;
>>>>>>>>>> +	struct device *dev = &pdev->dev;
>>>>>>>>>> +	struct resource *atu_dma_res;
>>>>>>>>>> +	struct tegra_pcie_dw *pcie;
>>>>>>>>>> +	struct resource *dbi_res;
>>>>>>>>>> +	struct pcie_port *pp;
>>>>>>>>>> +	struct dw_pcie *pci;
>>>>>>>>>> +	struct phy **phys;
>>>>>>>>>> +	char *name;
>>>>>>>>>> +	int ret;
>>>>>>>>>> +	u32 i;
>>>>>>>>>> +
>>>>>>>>>> +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
>>>>>>>>>> +	if (!pcie)
>>>>>>>>>> +		return -ENOMEM;
>>>>>>>>>> +
>>>>>>>>>> +	pci = &pcie->pci;
>>>>>>>>>> +	pci->dev = &pdev->dev;
>>>>>>>>>> +	pci->ops = &tegra_dw_pcie_ops;
>>>>>>>>>> +	pp = &pci->pp;
>>>>>>>>>> +	pcie->dev = &pdev->dev;
>>>>>>>>>> +
>>>>>>>>>> +	data = (struct tegra_pcie_soc *)of_device_get_match_data(dev);
>>>>>>>>>> +	if (!data)
>>>>>>>>>> +		return -EINVAL;
>>>>>>>>>> +	pcie->mode = (enum dw_pcie_device_mode)data->mode;
>>>>>>>>>> +
>>>>>>>>>> +	ret = tegra_pcie_dw_parse_dt(pcie);
>>>>>>>>>> +	if (ret < 0) {
>>>>>>>>>> +		dev_err(dev, "Failed to parse device tree: %d\n", ret);
>>>>>>>>>> +		return ret;
>>>>>>>>>> +	}
>>>>>>>>>> +
>>>>>>>>>> +	pcie->pex_ctl_supply = devm_regulator_get(dev, "vddio-pex-ctl");
>>>>>>>>>> +	if (IS_ERR(pcie->pex_ctl_supply)) {
>>>>>>>>>> +		dev_err(dev, "Failed to get regulator: %ld\n",
>>>>>>>>>> +			PTR_ERR(pcie->pex_ctl_supply));
>>>>>>>>>> +		return PTR_ERR(pcie->pex_ctl_supply);
>>>>>>>>>> +	}
>>>>>>>>>> +
>>>>>>>>>> +	pcie->core_clk = devm_clk_get(dev, "core");
>>>>>>>>>> +	if (IS_ERR(pcie->core_clk)) {
>>>>>>>>>> +		dev_err(dev, "Failed to get core clock: %ld\n",
>>>>>>>>>> +			PTR_ERR(pcie->core_clk));
>>>>>>>>>> +		return PTR_ERR(pcie->core_clk);
>>>>>>>>>> +	}
>>>>>>>>>> +
>>>>>>>>>> +	pcie->appl_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>>>>>>>>>> +						      "appl");
>>>>>>>>>> +	if (!pcie->appl_res) {
>>>>>>>>>> +		dev_err(dev, "Failed to find \"appl\" region\n");
>>>>>>>>>> +		return PTR_ERR(pcie->appl_res);
>>>>>>>>>> +	}
>>>>>>>>>> +	pcie->appl_base = devm_ioremap_resource(dev, pcie->appl_res);
>>>>>>>>>> +	if (IS_ERR(pcie->appl_base))
>>>>>>>>>> +		return PTR_ERR(pcie->appl_base);
>>>>>>>>>> +
>>>>>>>>>> +	pcie->core_apb_rst = devm_reset_control_get(dev, "apb");
>>>>>>>>>> +	if (IS_ERR(pcie->core_apb_rst)) {
>>>>>>>>>> +		dev_err(dev, "Failed to get APB reset: %ld\n",
>>>>>>>>>> +			PTR_ERR(pcie->core_apb_rst));
>>>>>>>>>> +		return PTR_ERR(pcie->core_apb_rst);
>>>>>>>>>> +	}
>>>>>>>>>> +
>>>>>>>>>> +	phys = devm_kcalloc(dev, pcie->phy_count, sizeof(*phys), GFP_KERNEL);
>>>>>>>>>> +	if (!phys)
>>>>>>>>>> +		return PTR_ERR(phys);
>>>>>>>>>> +
>>>>>>>>>> +	for (i = 0; i < pcie->phy_count; i++) {
>>>>>>>>>> +		name = kasprintf(GFP_KERNEL, "p2u-%u", i);
>>>>>>>>>> +		if (!name) {
>>>>>>>>>> +			dev_err(dev, "Failed to create P2U string\n");
>>>>>>>>>> +			return -ENOMEM;
>>>>>>>>>> +		}
>>>>>>>>>> +		phys[i] = devm_phy_get(dev, name);
>>>>>>>>>> +		kfree(name);
>>>>>>>>>> +		if (IS_ERR(phys[i])) {
>>>>>>>>>> +			ret = PTR_ERR(phys[i]);
>>>>>>>>>> +			dev_err(dev, "Failed to get PHY: %d\n", ret);
>>>>>>>>>> +			return ret;
>>>>>>>>>> +		}
>>>>>>>>>> +	}
>>>>>>>>>> +
>>>>>>>>>> +	pcie->phys = phys;
>>>>>>>>>> +
>>>>>>>>>> +	dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
>>>>>>>>>> +	if (!dbi_res) {
>>>>>>>>>> +		dev_err(dev, "Failed to find \"dbi\" region\n");
>>>>>>>>>> +		return PTR_ERR(dbi_res);
>>>>>>>>>> +	}
>>>>>>>>>> +	pcie->dbi_res = dbi_res;
>>>>>>>>>> +
>>>>>>>>>> +	pci->dbi_base = devm_ioremap_resource(dev, dbi_res);
>>>>>>>>>> +	if (IS_ERR(pci->dbi_base))
>>>>>>>>>> +		return PTR_ERR(pci->dbi_base);
>>>>>>>>>> +
>>>>>>>>>> +	/* Tegra HW locates DBI2 at a fixed offset from DBI */
>>>>>>>>>> +	pci->dbi_base2 = pci->dbi_base + 0x1000;
>>>>>>>>>> +
>>>>>>>>>> +	atu_dma_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>>>>>>>>>> +						   "atu_dma");
>>>>>>>>>> +	if (!atu_dma_res) {
>>>>>>>>>> +		dev_err(dev, "Failed to find \"atu_dma\" region\n");
>>>>>>>>>> +		return PTR_ERR(atu_dma_res);
>>>>>>>>>> +	}
>>>>>>>>>> +	pcie->atu_dma_res = atu_dma_res;
>>>>>>>>>> +	pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);
>>>>>>>>>> +	if (IS_ERR(pci->atu_base))
>>>>>>>>>> +		return PTR_ERR(pci->atu_base);
>>>>>>>>>> +
>>>>>>>>>> +	pcie->core_rst = devm_reset_control_get(dev, "core");
>>>>>>>>>> +	if (IS_ERR(pcie->core_rst)) {
>>>>>>>>>> +		dev_err(dev, "Failed to get core reset: %ld\n",
>>>>>>>>>> +			PTR_ERR(pcie->core_rst));
>>>>>>>>>> +		return PTR_ERR(pcie->core_rst);
>>>>>>>>>> +	}
>>>>>>>>>> +
>>>>>>>>>> +	pp->irq = platform_get_irq_byname(pdev, "intr");
>>>>>>>>>> +	if (!pp->irq) {
>>>>>>>>>> +		dev_err(dev, "Failed to get \"intr\" interrupt\n");
>>>>>>>>>> +		return -ENODEV;
>>>>>>>>>> +	}
>>>>>>>>>> +
>>>>>>>>>> +	ret = devm_request_irq(dev, pp->irq, tegra_pcie_irq_handler,
>>>>>>>>>> +			       IRQF_SHARED, "tegra-pcie-intr", pcie);
>>>>>>>>>> +	if (ret) {
>>>>>>>>>> +		dev_err(dev, "Failed to request IRQ %d: %d\n", pp->irq, ret);
>>>>>>>>>> +		return ret;
>>>>>>>>>> +	}
>>>>>>>>>> +
>>>>>>>>>> +	pcie->bpmp = tegra_bpmp_get(dev);
>>>>>>>>>> +	if (IS_ERR(pcie->bpmp))
>>>>>>>>>> +		return PTR_ERR(pcie->bpmp);
>>>>>>>>>> +
>>>>>>>>>> +	platform_set_drvdata(pdev, pcie);
>>>>>>>>>> +
>>>>>>>>>> +	if (pcie->mode == DW_PCIE_RC_TYPE) {
>>>>>>>>>> +		ret = tegra_pcie_config_rp(pcie);
>>>>>>>>>> +		if (ret && ret != -ENOMEDIUM)
>>>>>>>>>> +			goto fail;
>>>>>>>>>> +		else
>>>>>>>>>> +			return 0;
>>>>>>>>>
>>>>>>>>> So if the link is not up we still go ahead and make probe
>>>>>>>>> succeed. What for ?
>>>>>>>> We may need root port to be available to support hot-plugging of
>>>>>>>> endpoint devices, so, we don't fail the probe.
>>>>>>>
>>>>>>> We need it or we don't. If you do support hotplugging of endpoint
>>>>>>> devices point me at the code, otherwise link up failure means
>>>>>>> failure to probe.
>>>>>> Currently hotplugging of endpoint is not supported, but it is one of
>>>>>> the use cases that we may add support for in future.
>>>>>
>>>>> You should elaborate on this, I do not understand what you mean,
>>>>> either the root port(s) supports hotplug or it does not.
>>>>>
>>>>>> But, why should we fail probe if link up doesn't happen? As such,
>>>>>> nothing went wrong in terms of root port initialization right?  I
>>>>>> checked other DWC based implementations and following are not failing
>>>>>> the probe pci-dra7xx.c, pcie-armada8k.c, pcie-artpec6.c, pcie-histb.c,
>>>>>> pcie-kirin.c, pcie-spear13xx.c, pci-exynos.c, pci-imx6.c,
>>>>>> pci-keystone.c, pci-layerscape.c
>>>>>>
>>>>>> Although following do fail the probe if link is not up.  pcie-qcom.c,
>>>>>> pcie-uniphier.c, pci-meson.c
>>>>>>
>>>>>> So, to me, it looks more like a choice we can make whether to fail the
>>>>>> probe or not and in this case we are choosing not to fail.
>>>>>
>>>>> I disagree. I had an offline chat with Bjorn and whether link-up should
>>>>> fail the probe or not depends on whether the root port(s) is hotplug
>>>>> capable or not and this in turn relies on the root port "Slot
>>>>> implemented" bit in the PCI Express capabilities register.
>>>>>
>>>>> It is a choice but it should be based on evidence.
>>>>>
>>>>> Lorenzo
>>>> With Bjorn's latest comment on top of this, I think we are good not to fail
>>>> the probe here.
>>>>
>>>> - Vidya Sagar
>>>>>
>>>>
>>

On Mon, Aug 05, 2019 at 10:24:42PM +0530, Vidya Sagar wrote:

[...]

> > > > IRQs are enabled when you call a suspend_noirq() callback, so the
> > > > blocking API can be used as long as the IRQ descriptor backing
> > > > the IRQ that will wake-up the blocked call is marked as
> > > > IRQF_NO_SUSPEND.
> > > > 
> > > > The problem is not IRQs enabled/disabled at CPU level, the problem is
> > > > the IRQ descriptor of the IRQ required to handle the blocking BPMP call,
> > > > mark it as IRQF_NO_SUSPEND and remove the tegra_bpmp_transfer_atomic()
> > > > call from this code (or please give me a concrete example pinpointing
> > > > why it is needed).
> > > Ideally, using tegra_bpmp_transfer() alone in all paths (.probe() as
> > > well as .resume_noirq()) should have worked as the corresponding IRQ
> > > is already flagged as IRQF_NO_SUSPEND, but, because of the way BPMP-FW
> > > driver in kernel making its interface available through
> > > .resume_early(), tegra_bpmp_transfer() wasn't working as expected and
> > > I pushed a patch (CC'ing you) at
> > > http://patchwork.ozlabs.org/patch/1140973/ to make it .resume_noirq()
> > > from .resume_early().  With that in place, we can just use
> > > tegra_bpmp_trasnfer().  I'll push a new patch with this change once my
> > > BPMP-FW driver patch is approved.
> > 
> > Does this leave you with a resume_noirq() callbacks ordering issue to
> > sort out ?
> Not really.
> 
> > 
> > a.k.a How will you guarantee that the BPMP will resume before the host
> > bridge ?
> It is already taken care of in the following way.  PCIe controller's
> device-tree node has an entry with a phandle of BPMP-FW's node to get
> a handle of it and PCIe driver uses tegra_bpmp_get() API for that.
> This API returns -EPROBE_DEFER if BPMP-FW's driver is not ready yet,
> which guarantees that PCIe driver gets loaded only after BPMP-FW's
> driver and this order is followed during noirq phase also.

OK, thanks, this makes much more sense than the original code.

Lorenzo

> > Thanks,
> > Lorenzo
> > 
> > > Thanks,
> > > Vidya Sagar
> > > > 
> > > > Thanks,
> > > > Lorenzo
> > > > 
> > > > > I'll go ahead and make next patch series with this if this looks fine to you.
> > > > > 
> > > > > > 
> > > > > > > > Actually, if tegra_bpmp_transfer() requires IRQs to be enabled you may
> > > > > > > > even end up in a situation where that blocking call does not wake up
> > > > > > > > because the IRQ in question was disabled in the NOIRQ suspend/resume
> > > > > > > > phase.
> > > > > > > > 
> > > > > > > > [...]
> > > > > > > > 
> > > > > > > > > > > +static int tegra_pcie_dw_probe(struct platform_device *pdev)
> > > > > > > > > > > +{
> > > > > > > > > > > +	const struct tegra_pcie_soc *data;
> > > > > > > > > > > +	struct device *dev = &pdev->dev;
> > > > > > > > > > > +	struct resource *atu_dma_res;
> > > > > > > > > > > +	struct tegra_pcie_dw *pcie;
> > > > > > > > > > > +	struct resource *dbi_res;
> > > > > > > > > > > +	struct pcie_port *pp;
> > > > > > > > > > > +	struct dw_pcie *pci;
> > > > > > > > > > > +	struct phy **phys;
> > > > > > > > > > > +	char *name;
> > > > > > > > > > > +	int ret;
> > > > > > > > > > > +	u32 i;
> > > > > > > > > > > +
> > > > > > > > > > > +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> > > > > > > > > > > +	if (!pcie)
> > > > > > > > > > > +		return -ENOMEM;
> > > > > > > > > > > +
> > > > > > > > > > > +	pci = &pcie->pci;
> > > > > > > > > > > +	pci->dev = &pdev->dev;
> > > > > > > > > > > +	pci->ops = &tegra_dw_pcie_ops;
> > > > > > > > > > > +	pp = &pci->pp;
> > > > > > > > > > > +	pcie->dev = &pdev->dev;
> > > > > > > > > > > +
> > > > > > > > > > > +	data = (struct tegra_pcie_soc *)of_device_get_match_data(dev);
> > > > > > > > > > > +	if (!data)
> > > > > > > > > > > +		return -EINVAL;
> > > > > > > > > > > +	pcie->mode = (enum dw_pcie_device_mode)data->mode;
> > > > > > > > > > > +
> > > > > > > > > > > +	ret = tegra_pcie_dw_parse_dt(pcie);
> > > > > > > > > > > +	if (ret < 0) {
> > > > > > > > > > > +		dev_err(dev, "Failed to parse device tree: %d\n", ret);
> > > > > > > > > > > +		return ret;
> > > > > > > > > > > +	}
> > > > > > > > > > > +
> > > > > > > > > > > +	pcie->pex_ctl_supply = devm_regulator_get(dev, "vddio-pex-ctl");
> > > > > > > > > > > +	if (IS_ERR(pcie->pex_ctl_supply)) {
> > > > > > > > > > > +		dev_err(dev, "Failed to get regulator: %ld\n",
> > > > > > > > > > > +			PTR_ERR(pcie->pex_ctl_supply));
> > > > > > > > > > > +		return PTR_ERR(pcie->pex_ctl_supply);
> > > > > > > > > > > +	}
> > > > > > > > > > > +
> > > > > > > > > > > +	pcie->core_clk = devm_clk_get(dev, "core");
> > > > > > > > > > > +	if (IS_ERR(pcie->core_clk)) {
> > > > > > > > > > > +		dev_err(dev, "Failed to get core clock: %ld\n",
> > > > > > > > > > > +			PTR_ERR(pcie->core_clk));
> > > > > > > > > > > +		return PTR_ERR(pcie->core_clk);
> > > > > > > > > > > +	}
> > > > > > > > > > > +
> > > > > > > > > > > +	pcie->appl_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > > > > > > > > > > +						      "appl");
> > > > > > > > > > > +	if (!pcie->appl_res) {
> > > > > > > > > > > +		dev_err(dev, "Failed to find \"appl\" region\n");
> > > > > > > > > > > +		return PTR_ERR(pcie->appl_res);
> > > > > > > > > > > +	}
> > > > > > > > > > > +	pcie->appl_base = devm_ioremap_resource(dev, pcie->appl_res);
> > > > > > > > > > > +	if (IS_ERR(pcie->appl_base))
> > > > > > > > > > > +		return PTR_ERR(pcie->appl_base);
> > > > > > > > > > > +
> > > > > > > > > > > +	pcie->core_apb_rst = devm_reset_control_get(dev, "apb");
> > > > > > > > > > > +	if (IS_ERR(pcie->core_apb_rst)) {
> > > > > > > > > > > +		dev_err(dev, "Failed to get APB reset: %ld\n",
> > > > > > > > > > > +			PTR_ERR(pcie->core_apb_rst));
> > > > > > > > > > > +		return PTR_ERR(pcie->core_apb_rst);
> > > > > > > > > > > +	}
> > > > > > > > > > > +
> > > > > > > > > > > +	phys = devm_kcalloc(dev, pcie->phy_count, sizeof(*phys), GFP_KERNEL);
> > > > > > > > > > > +	if (!phys)
> > > > > > > > > > > +		return PTR_ERR(phys);
> > > > > > > > > > > +
> > > > > > > > > > > +	for (i = 0; i < pcie->phy_count; i++) {
> > > > > > > > > > > +		name = kasprintf(GFP_KERNEL, "p2u-%u", i);
> > > > > > > > > > > +		if (!name) {
> > > > > > > > > > > +			dev_err(dev, "Failed to create P2U string\n");
> > > > > > > > > > > +			return -ENOMEM;
> > > > > > > > > > > +		}
> > > > > > > > > > > +		phys[i] = devm_phy_get(dev, name);
> > > > > > > > > > > +		kfree(name);
> > > > > > > > > > > +		if (IS_ERR(phys[i])) {
> > > > > > > > > > > +			ret = PTR_ERR(phys[i]);
> > > > > > > > > > > +			dev_err(dev, "Failed to get PHY: %d\n", ret);
> > > > > > > > > > > +			return ret;
> > > > > > > > > > > +		}
> > > > > > > > > > > +	}
> > > > > > > > > > > +
> > > > > > > > > > > +	pcie->phys = phys;
> > > > > > > > > > > +
> > > > > > > > > > > +	dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
> > > > > > > > > > > +	if (!dbi_res) {
> > > > > > > > > > > +		dev_err(dev, "Failed to find \"dbi\" region\n");
> > > > > > > > > > > +		return PTR_ERR(dbi_res);
> > > > > > > > > > > +	}
> > > > > > > > > > > +	pcie->dbi_res = dbi_res;
> > > > > > > > > > > +
> > > > > > > > > > > +	pci->dbi_base = devm_ioremap_resource(dev, dbi_res);
> > > > > > > > > > > +	if (IS_ERR(pci->dbi_base))
> > > > > > > > > > > +		return PTR_ERR(pci->dbi_base);
> > > > > > > > > > > +
> > > > > > > > > > > +	/* Tegra HW locates DBI2 at a fixed offset from DBI */
> > > > > > > > > > > +	pci->dbi_base2 = pci->dbi_base + 0x1000;
> > > > > > > > > > > +
> > > > > > > > > > > +	atu_dma_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > > > > > > > > > > +						   "atu_dma");
> > > > > > > > > > > +	if (!atu_dma_res) {
> > > > > > > > > > > +		dev_err(dev, "Failed to find \"atu_dma\" region\n");
> > > > > > > > > > > +		return PTR_ERR(atu_dma_res);
> > > > > > > > > > > +	}
> > > > > > > > > > > +	pcie->atu_dma_res = atu_dma_res;
> > > > > > > > > > > +	pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);
> > > > > > > > > > > +	if (IS_ERR(pci->atu_base))
> > > > > > > > > > > +		return PTR_ERR(pci->atu_base);
> > > > > > > > > > > +
> > > > > > > > > > > +	pcie->core_rst = devm_reset_control_get(dev, "core");
> > > > > > > > > > > +	if (IS_ERR(pcie->core_rst)) {
> > > > > > > > > > > +		dev_err(dev, "Failed to get core reset: %ld\n",
> > > > > > > > > > > +			PTR_ERR(pcie->core_rst));
> > > > > > > > > > > +		return PTR_ERR(pcie->core_rst);
> > > > > > > > > > > +	}
> > > > > > > > > > > +
> > > > > > > > > > > +	pp->irq = platform_get_irq_byname(pdev, "intr");
> > > > > > > > > > > +	if (!pp->irq) {
> > > > > > > > > > > +		dev_err(dev, "Failed to get \"intr\" interrupt\n");
> > > > > > > > > > > +		return -ENODEV;
> > > > > > > > > > > +	}
> > > > > > > > > > > +
> > > > > > > > > > > +	ret = devm_request_irq(dev, pp->irq, tegra_pcie_irq_handler,
> > > > > > > > > > > +			       IRQF_SHARED, "tegra-pcie-intr", pcie);
> > > > > > > > > > > +	if (ret) {
> > > > > > > > > > > +		dev_err(dev, "Failed to request IRQ %d: %d\n", pp->irq, ret);
> > > > > > > > > > > +		return ret;
> > > > > > > > > > > +	}
> > > > > > > > > > > +
> > > > > > > > > > > +	pcie->bpmp = tegra_bpmp_get(dev);
> > > > > > > > > > > +	if (IS_ERR(pcie->bpmp))
> > > > > > > > > > > +		return PTR_ERR(pcie->bpmp);
> > > > > > > > > > > +
> > > > > > > > > > > +	platform_set_drvdata(pdev, pcie);
> > > > > > > > > > > +
> > > > > > > > > > > +	if (pcie->mode == DW_PCIE_RC_TYPE) {
> > > > > > > > > > > +		ret = tegra_pcie_config_rp(pcie);
> > > > > > > > > > > +		if (ret && ret != -ENOMEDIUM)
> > > > > > > > > > > +			goto fail;
> > > > > > > > > > > +		else
> > > > > > > > > > > +			return 0;
> > > > > > > > > > 
> > > > > > > > > > So if the link is not up we still go ahead and make probe
> > > > > > > > > > succeed. What for ?
> > > > > > > > > We may need root port to be available to support hot-plugging of
> > > > > > > > > endpoint devices, so, we don't fail the probe.
> > > > > > > > 
> > > > > > > > We need it or we don't. If you do support hotplugging of endpoint
> > > > > > > > devices point me at the code, otherwise link up failure means
> > > > > > > > failure to probe.
> > > > > > > Currently hotplugging of endpoint is not supported, but it is one of
> > > > > > > the use cases that we may add support for in future.
> > > > > > 
> > > > > > You should elaborate on this, I do not understand what you mean,
> > > > > > either the root port(s) supports hotplug or it does not.
> > > > > > 
> > > > > > > But, why should we fail probe if link up doesn't happen? As such,
> > > > > > > nothing went wrong in terms of root port initialization right?  I
> > > > > > > checked other DWC based implementations and following are not failing
> > > > > > > the probe pci-dra7xx.c, pcie-armada8k.c, pcie-artpec6.c, pcie-histb.c,
> > > > > > > pcie-kirin.c, pcie-spear13xx.c, pci-exynos.c, pci-imx6.c,
> > > > > > > pci-keystone.c, pci-layerscape.c
> > > > > > > 
> > > > > > > Although following do fail the probe if link is not up.  pcie-qcom.c,
> > > > > > > pcie-uniphier.c, pci-meson.c
> > > > > > > 
> > > > > > > So, to me, it looks more like a choice we can make whether to fail the
> > > > > > > probe or not and in this case we are choosing not to fail.
> > > > > > 
> > > > > > I disagree. I had an offline chat with Bjorn and whether link-up should
> > > > > > fail the probe or not depends on whether the root port(s) is hotplug
> > > > > > capable or not and this in turn relies on the root port "Slot
> > > > > > implemented" bit in the PCI Express capabilities register.
> > > > > > 
> > > > > > It is a choice but it should be based on evidence.
> > > > > > 
> > > > > > Lorenzo
> > > > > With Bjorn's latest comment on top of this, I think we are good not to fail
> > > > > the probe here.
> > > > > 
> > > > > - Vidya Sagar
> > > > > > 
> > > > > 
> > > 
>