[2/2] PCI: keembay: Add support for Intel Keem Bay

Add driver for Intel Keem Bay SoC PCIe controller. This controller
is based on DesignWare PCIe core.

In root complex mode, only internal reference clock is possible for
Keem Bay A0. For Keem Bay B0, external reference clock can be used
and will be the default configuration. Currently, keembay_pcie_of_data
structure has one member. It will be expanded later to handle this
difference.

Endpoint mode link initialization is handled by the boot firmware.

Signed-off-by: Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/pci/controller/dwc/Kconfig        |  24 +
 drivers/pci/controller/dwc/Makefile       |   1 +
 drivers/pci/controller/dwc/pcie-keembay.c | 658 ++++++++++++++++++++++
 3 files changed, 683 insertions(+)
 create mode 100644 drivers/pci/controller/dwc/pcie-keembay.c

On Tue, Oct 27, 2020 at 02:00:11PM +0800, Wan Ahmad Zainie wrote:
> Add driver for Intel Keem Bay SoC PCIe controller. This controller
> is based on DesignWare PCIe core.
> 
> In root complex mode, only internal reference clock is possible for
> Keem Bay A0. For Keem Bay B0, external reference clock can be used
> and will be the default configuration. Currently, keembay_pcie_of_data
> structure has one member. It will be expanded later to handle this
> difference.
> 
> Endpoint mode link initialization is handled by the boot firmware.
> 
> Signed-off-by: Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>
> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  drivers/pci/controller/dwc/Kconfig        |  24 +
>  drivers/pci/controller/dwc/Makefile       |   1 +
>  drivers/pci/controller/dwc/pcie-keembay.c | 658 ++++++++++++++++++++++
>  3 files changed, 683 insertions(+)
>  create mode 100644 drivers/pci/controller/dwc/pcie-keembay.c
> 
> diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
> index bc049865f8e0..694a1fcacb73 100644
> --- a/drivers/pci/controller/dwc/Kconfig
> +++ b/drivers/pci/controller/dwc/Kconfig
> @@ -219,6 +219,30 @@ config PCIE_INTEL_GW
>  	  The PCIe controller uses the DesignWare core plus Intel-specific
>  	  hardware wrappers.
>  
> +config PCIE_KEEMBAY
> +	bool
> +
> +config PCIE_KEEMBAY_HOST
> +	bool "Intel Keem Bay PCIe controller - Host mode"
> +	depends on ARCH_KEEMBAY || (ARM64 && COMPILE_TEST)

Why only ARM64 for compile test?

> +	depends on PCI && PCI_MSI_IRQ_DOMAIN
> +	select PCIE_DW_HOST
> +	select PCIE_KEEMBAY
> +	help
> +	  Say Y here to enable support for the PCIe controller in Keem Bay
> +	  to work in host mode. This uses the DesignWare core.
> +
> +config PCIE_KEEMBAY_EP
> +	bool "Intel Keem Bay PCIe controller - Endpoint mode"
> +	depends on ARCH_KEEMBAY || (ARM64 && COMPILE_TEST)
> +	depends on PCI && PCI_MSI_IRQ_DOMAIN
> +	depends on PCI_ENDPOINT
> +	select PCIE_DW_EP
> +	select PCIE_KEEMBAY
> +	help
> +	  Say Y here to enable support for the PCIe controller in Keem Bay
> +	  to work in endpoint mode. This uses the DesignWare core.
> +
>  config PCIE_KIRIN
>  	depends on OF && (ARM64 || COMPILE_TEST)
>  	bool "HiSilicon Kirin series SoCs PCIe controllers"
> diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
> index a751553fa0db..95da2c62c426 100644
> --- a/drivers/pci/controller/dwc/Makefile
> +++ b/drivers/pci/controller/dwc/Makefile
> @@ -14,6 +14,7 @@ obj-$(CONFIG_PCIE_QCOM) += pcie-qcom.o
>  obj-$(CONFIG_PCIE_ARMADA_8K) += pcie-armada8k.o
>  obj-$(CONFIG_PCIE_ARTPEC6) += pcie-artpec6.o
>  obj-$(CONFIG_PCIE_INTEL_GW) += pcie-intel-gw.o
> +obj-$(CONFIG_PCIE_KEEMBAY) += pcie-keembay.o
>  obj-$(CONFIG_PCIE_KIRIN) += pcie-kirin.o
>  obj-$(CONFIG_PCIE_HISI_STB) += pcie-histb.o
>  obj-$(CONFIG_PCI_MESON) += pci-meson.o
> diff --git a/drivers/pci/controller/dwc/pcie-keembay.c b/drivers/pci/controller/dwc/pcie-keembay.c
> new file mode 100644
> index 000000000000..30401ef223ca
> --- /dev/null
> +++ b/drivers/pci/controller/dwc/pcie-keembay.c
> @@ -0,0 +1,658 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * PCIe controller driver for Intel Keem Bay
> + * Copyright (C) 2020 Intel Corporation
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/bits.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/init.h>
> +#include <linux/iopoll.h>
> +#include <linux/kernel.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.h>
> +
> +#include "pcie-designware.h"
> +
> +/* PCIE_REGS_APB_SLV Registers */
> +#define PCIE_REGS_PCIE_CFG		0x0004
> +#define  PCIE_DEVICE_TYPE		BIT(8)
> +#define  PCIE_RSTN			BIT(0)
> +#define PCIE_REGS_PCIE_APP_CNTRL	0x0008
> +#define  APP_LTSSM_ENABLE		BIT(0)
> +
> +#define PCIE_REGS_PCIE_INTR_ENABLE	0x0018
> +#define  LBC_CII_EVENT_EN		BIT(18)
> +#define PCIE_REGS_PCIE_INTR_FLAGS	0x001c
> +#define PCIE_REGS_PCIE_ERR_INTR_ENABLE	0x0020
> +#define  LINK_REQ_RST_EN		BIT(15)
> +#define PCIE_REGS_PCIE_ERR_INTR_FLAGS	0x0024
> +#define PCIE_REGS_INTERRUPT_ENABLE	0x0028
> +#define  MSI_CTRL_INT_EN		BIT(8)
> +#define  EDMA_INT_EN			GENMASK(7, 0)
> +#define PCIE_REGS_INTERRUPT_STATUS	0x002c
> +#define  MSI_CTRL_INT			BIT(8)
> +
> +#define PCIE_REGS_PCIE_SII_PM_STATE	0x00b0
> +#define  SMLH_LINK_UP			BIT(19)
> +#define  RDLH_LINK_UP			BIT(8)
> +#define PCIE_REGS_PCIE_PHY_CNTL		0x0164
> +#define  PHY0_SRAM_BYPASS		BIT(8)
> +#define PCIE_REGS_PCIE_PHY_STAT		0x0168
> +#define  PHY0_MPLLA_STATE		BIT(1)
> +#define PCIE_REGS_LJPLL_STA		0x016c
> +#define  LJPLL_LOCK			BIT(0)
> +#define PCIE_REGS_LJPLL_CNTRL_0		0x0170
> +#define  LJPLL_EN			BIT(29)
> +#define  LJPLL_FOUT_EN			GENMASK(24, 21)
> +#define PCIE_REGS_LJPLL_CNTRL_2		0x0178
> +#define  LJPLL_REF_DIV			GENMASK(17, 12)
> +#define  LJPLL_FB_DIV			GENMASK(11, 0)
> +#define PCIE_REGS_LJPLL_CNTRL_3		0x017c
> +#define  LJPLL_POST_DIV3A		GENMASK(24, 22)
> +#define  LJPLL_POST_DIV2A		GENMASK(18, 16)
> +
> +#define PCIE_REGS_MEM_ACCESS_IRQ_ENABLE	0x0184
> +#define  MEM_ACCESS_IRQ_ENABLE		GENMASK(31, 0)
> +
> +#define PCIE_DBI2_MASK		BIT(20)
> +#define PERST_DELAY_US		1000
> +#define AUX_CLK_RATE_HZ		24000000
> +
> +struct keembay_pcie {
> +	struct dw_pcie		*pci;

Make this a struct, not a pointer. Then one less alloc.

> +	void __iomem		*apb_base;
> +	enum dw_pcie_device_mode mode;
> +
> +	int			irq;
> +	int			ev_irq;
> +	int			err_irq;
> +	int			mem_access_irq;

There's no need to store the irq numbers forever.

> +
> +	struct clk		*clk_master;
> +	struct clk		*clk_aux;
> +	struct gpio_desc	*reset;
> +};
> +
> +struct keembay_pcie_of_data {
> +	enum dw_pcie_device_mode mode;
> +};
> +
> +static inline u32 keembay_pcie_readl(struct keembay_pcie *pcie, u32 offset)
> +{
> +	return readl(pcie->apb_base + offset);
> +}
> +
> +static inline void keembay_pcie_writel(struct keembay_pcie *pcie, u32 offset,
> +				       u32 value)
> +{
> +	writel(value, pcie->apb_base + offset);
> +}
> +
> +static void keembay_ep_reset_assert(struct keembay_pcie *pcie)
> +{
> +	gpiod_set_value_cansleep(pcie->reset, 1);
> +	usleep_range(PERST_DELAY_US, PERST_DELAY_US + 500);
> +}
> +
> +static void keembay_ep_reset_deassert(struct keembay_pcie *pcie)
> +{
> +	/* Ensure that PERST has been asserted for at least 100ms */
> +	msleep(100);
> +
> +	gpiod_set_value_cansleep(pcie->reset, 0);
> +	usleep_range(PERST_DELAY_US, PERST_DELAY_US + 500);
> +}
> +
> +static void keembay_pcie_ltssm_enable(struct keembay_pcie *pcie, bool enable)
> +{
> +	u32 val;
> +
> +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_APP_CNTRL);
> +	if (enable)
> +		val |= APP_LTSSM_ENABLE;
> +	else
> +		val &= ~APP_LTSSM_ENABLE;
> +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_APP_CNTRL, val);
> +}
> +
> +static int keembay_pcie_link_up(struct dw_pcie *pci)
> +{
> +	struct keembay_pcie *pcie = dev_get_drvdata(pci->dev);
> +	u32 val, mask;
> +
> +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_SII_PM_STATE);
> +	mask = SMLH_LINK_UP | RDLH_LINK_UP;
> +
> +	return !!((val & mask) == mask);
> +}
> +
> +static int keembay_pcie_establish_link(struct dw_pcie *pci)

_start_link() to align with the ops name.

> +{
> +	return 0;

Shouldn't this call keembay_pcie_ltssm_enable?

> +}
> +
> +static void keembay_pcie_stop_link(struct dw_pcie *pci)
> +{
> +	struct keembay_pcie *pcie = dev_get_drvdata(pci->dev);
> +
> +	keembay_pcie_ltssm_enable(pcie, false);
> +}
> +
> +static const struct dw_pcie_ops keembay_pcie_ops = {
> +	.link_up	= keembay_pcie_link_up,
> +	.start_link	= keembay_pcie_establish_link,
> +	.stop_link	= keembay_pcie_stop_link,
> +};
> +
> +/*
> + * Initialize the internal PCIe PLL in Host mode.
> + * See the following sections in Keem Bay data book,
> + * (1) 6.4.6.1 PCIe Subsystem Example Initialization,
> + * (2) 6.8 PCIe Low Jitter PLL for Ref Clk Generation.
> + */
> +static int keembay_pcie_pll_init(struct keembay_pcie *pcie)
> +{
> +	struct dw_pcie *pci = pcie->pci;
> +	u32 val;
> +	int ret;
> +
> +	val = FIELD_PREP(LJPLL_REF_DIV, 0) | FIELD_PREP(LJPLL_FB_DIV, 0x32);
> +	keembay_pcie_writel(pcie, PCIE_REGS_LJPLL_CNTRL_2, val);
> +
> +	val = FIELD_PREP(LJPLL_POST_DIV3A, 0x2) |
> +		FIELD_PREP(LJPLL_POST_DIV2A, 0x2);
> +	keembay_pcie_writel(pcie, PCIE_REGS_LJPLL_CNTRL_3, val);
> +
> +	val = FIELD_PREP(LJPLL_EN, 0x1) | FIELD_PREP(LJPLL_FOUT_EN, 0xc);
> +	keembay_pcie_writel(pcie, PCIE_REGS_LJPLL_CNTRL_0, val);
> +
> +	ret = readl_poll_timeout(pcie->apb_base + PCIE_REGS_LJPLL_STA,
> +				 val, val & LJPLL_LOCK, 20,
> +				 500 * USEC_PER_MSEC);
> +	if (ret)
> +		dev_err(pci->dev, "Low jitter PLL is not locked\n");
> +
> +	return ret;
> +}
> +
> +static irqreturn_t keembay_pcie_irq_handler(int irq, void *arg)
> +{
> +	struct keembay_pcie *pcie = arg;
> +	struct dw_pcie *pci = pcie->pci;
> +	struct pcie_port *pp = &pci->pp;
> +	u32 val, mask, status;
> +
> +	val = keembay_pcie_readl(pcie, PCIE_REGS_INTERRUPT_STATUS);
> +	mask = keembay_pcie_readl(pcie, PCIE_REGS_INTERRUPT_ENABLE);
> +
> +	status = val & mask;
> +	if (!status)
> +		return IRQ_NONE;
> +
> +	if (status & MSI_CTRL_INT)
> +		dw_handle_msi_irq(pp);
> +
> +	keembay_pcie_writel(pcie, PCIE_REGS_INTERRUPT_STATUS, status);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t keembay_pcie_ev_irq_handler(int irq, void *arg)
> +{
> +	struct keembay_pcie *pcie = arg;
> +	u32 val, mask, status;
> +
> +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_INTR_FLAGS);
> +	mask = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_INTR_ENABLE);
> +
> +	status = val & mask;
> +	if (!status)
> +		return IRQ_NONE;
> +
> +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_INTR_FLAGS, status);

Why an interrupt handler that doesn't do anything?

> +
> +	return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t keembay_pcie_err_irq_handler(int irq, void *arg)
> +{
> +	struct keembay_pcie *pcie = arg;
> +	u32 val, mask, status;
> +
> +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_ERR_INTR_FLAGS);
> +	mask = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_ERR_INTR_ENABLE);
> +
> +	status = val & mask;
> +	if (!status)
> +		return IRQ_NONE;
> +
> +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_ERR_INTR_FLAGS, status);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int keembay_pcie_setup_irq(struct keembay_pcie *pcie)
> +{
> +
> +	struct dw_pcie *pci = pcie->pci;
> +	struct device *dev = pci->dev;
> +	struct platform_device *pdev = to_platform_device(dev);
> +	int ret;
> +
> +	pcie->irq = platform_get_irq_byname(pdev, "intr");
> +	if (pcie->irq < 0)
> +		return pcie->irq;
> +
> +	pcie->ev_irq = platform_get_irq_byname(pdev, "ev_intr");
> +	if (pcie->ev_irq < 0)
> +		return pcie->ev_irq;
> +
> +	pcie->err_irq = platform_get_irq_byname(pdev, "err_intr");
> +	if (pcie->err_irq < 0)
> +		return pcie->err_irq;
> +
> +	if (pcie->mode == DW_PCIE_EP_TYPE) {
> +		int irq;
> +
> +		irq = platform_get_irq_byname(pdev, "mem_access_intr");
> +		if (irq < 0)
> +			return irq;
> +
> +		pcie->mem_access_irq = irq;
> +		return 0;
> +	}
> +
> +	ret = devm_request_irq(dev, pcie->irq, keembay_pcie_irq_handler,
> +			       IRQF_SHARED | IRQF_NO_THREAD, "pcie-intr", pcie);
> +	if (ret) {
> +		dev_err(dev, "Failed to request IRQ: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = devm_request_irq(dev, pcie->ev_irq, keembay_pcie_ev_irq_handler,
> +			       0, "pcie-ev-intr", pcie);
> +	if (ret) {
> +		dev_err(dev, "Failed to request event IRQ: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = devm_request_irq(dev, pcie->err_irq, keembay_pcie_err_irq_handler,
> +			       0, "pcie-err-intr", pcie);
> +	if (ret)
> +		dev_err(dev, "Failed to request error IRQ: %d\n", ret);
> +
> +	return ret;
> +}
> +
> +static int keembay_pcie_rc_establish_link(struct dw_pcie *pci)
> +{
> +	struct keembay_pcie *pcie = dev_get_drvdata(pci->dev);
> +	u32 val;
> +	int ret;
> +
> +	if (dw_pcie_link_up(pci))
> +		return 0;
> +
> +	keembay_pcie_ltssm_enable(pcie, false);
> +
> +	ret = readl_poll_timeout(pcie->apb_base + PCIE_REGS_PCIE_PHY_STAT,
> +				 val, val & PHY0_MPLLA_STATE, 20,
> +				 500 * USEC_PER_MSEC);
> +	if (ret) {
> +		dev_err(pci->dev, "MPLLA is not locked\n");
> +		return ret;
> +	}
> +
> +	keembay_pcie_ltssm_enable(pcie, true);
> +
> +	return dw_pcie_wait_for_link(pci);
> +}
> +
> +static void keembay_pcie_enable_interrupts(struct keembay_pcie *pcie)
> +{
> +	u32 val;
> +
> +	/* Enable interrupt */
> +	val = keembay_pcie_readl(pcie, PCIE_REGS_INTERRUPT_ENABLE);
> +
> +	if (IS_ENABLED(CONFIG_PCI_MSI))
> +		val |= MSI_CTRL_INT_EN;
> +
> +	keembay_pcie_writel(pcie, PCIE_REGS_INTERRUPT_ENABLE, val);
> +
> +	/* Enable event interrupt */
> +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_INTR_ENABLE);
> +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_INTR_ENABLE, val);
> +
> +	/* Enable error interrupt */
> +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_ERR_INTR_ENABLE);
> +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_ERR_INTR_ENABLE, val);
> +}
> +
> +static int __init keembay_pcie_host_init(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct keembay_pcie *pcie = dev_get_drvdata(pci->dev);
> +	int ret;
> +
> +	dw_pcie_setup_rc(pp);
> +	ret = keembay_pcie_rc_establish_link(pci);
> +	if (ret)
> +		return ret;
> +
> +	if (IS_ENABLED(CONFIG_PCI_MSI))
> +		dw_pcie_msi_init(pp);
> +
> +	keembay_pcie_enable_interrupts(pcie);
> +
> +	/* Disable BARs */

Why? I don't see other DWC drivers doing this.

> +	dw_pcie_dbi_ro_wr_en(pci);
> +	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0 | PCIE_DBI2_MASK, 0);
> +	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_1 | PCIE_DBI2_MASK, 0);
> +	dw_pcie_dbi_ro_wr_dis(pci);
> +
> +	return 0;
> +}
> +
> +static const struct dw_pcie_host_ops keembay_pcie_host_ops = {
> +	.host_init	= keembay_pcie_host_init,
> +};
> +
> +static void keembay_pcie_ep_init(struct dw_pcie_ep *ep)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> +	struct keembay_pcie *pcie = dev_get_drvdata(pci->dev);
> +	u32 val;
> +
> +	/* Enable DMA completion/error interrupts */
> +	val = keembay_pcie_readl(pcie, PCIE_REGS_INTERRUPT_ENABLE);
> +	keembay_pcie_writel(pcie, PCIE_REGS_INTERRUPT_ENABLE,
> +			    val | EDMA_INT_EN);
> +
> +	/* Enable CII event interrupt */
> +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_INTR_ENABLE);
> +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_INTR_ENABLE,
> +			    val | LBC_CII_EVENT_EN);
> +
> +	/* Enable link request reset */
> +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_ERR_INTR_ENABLE);
> +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_ERR_INTR_ENABLE,
> +			    val | LINK_REQ_RST_EN);
> +
> +	/* Enable host memory access interrupt */
> +	keembay_pcie_writel(pcie, PCIE_REGS_MEM_ACCESS_IRQ_ENABLE,
> +			    MEM_ACCESS_IRQ_ENABLE);
> +}
> +
> +static int keembay_pcie_ep_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
> +				     enum pci_epc_irq_type type,
> +				     u16 interrupt_num)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> +
> +	switch (type) {
> +	case PCI_EPC_IRQ_LEGACY:
> +		/* Legacy interrupts are not supported in Keem Bay */
> +		dev_err(pci->dev, "Unsupported IRQ type\n");
> +		return -EINVAL;
> +	case PCI_EPC_IRQ_MSI:
> +		return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
> +	case PCI_EPC_IRQ_MSIX:
> +		return dw_pcie_ep_raise_msix_irq(ep, func_no, interrupt_num);
> +	default:
> +		dev_err(pci->dev, "Unknown IRQ type\n");
> +		return -EINVAL;
> +	}
> +}
> +
> +static const struct pci_epc_features keembay_pcie_epc_features = {
> +	.linkup_notifier	= false,
> +	.msi_capable		= true,
> +	.msix_capable		= true,
> +	.reserved_bar		= BIT(BAR_1) | BIT(BAR_3) | BIT(BAR_5),
> +	.bar_fixed_64bit	= BIT(BAR_0) | BIT(BAR_2) | BIT(BAR_4),
> +	.align			= SZ_16K,
> +};
> +
> +static const struct pci_epc_features *
> +keembay_pcie_get_features(struct dw_pcie_ep *ep)
> +{
> +	return &keembay_pcie_epc_features;
> +}
> +
> +static const struct dw_pcie_ep_ops keembay_pcie_ep_ops = {
> +	.ep_init	= keembay_pcie_ep_init,
> +	.raise_irq	= keembay_pcie_ep_raise_irq,
> +	.get_features	= keembay_pcie_get_features,
> +};
> +
> +static inline struct clk *keembay_pcie_probe_clock(struct device *dev,
> +						   const char *id, u64 rate)
> +{
> +	struct clk *clk;
> +	int ret;
> +
> +	clk = devm_clk_get(dev, id);
> +	if (IS_ERR(clk))
> +		return clk;
> +
> +	if (rate) {
> +		ret = clk_set_rate(clk, rate);
> +		if (ret)
> +			return ERR_PTR(ret);
> +	}
> +
> +	ret = clk_prepare_enable(clk);
> +	if (ret)
> +		return ERR_PTR(ret);
> +
> +	ret = devm_add_action_or_reset(dev,
> +				       (void(*)(void *))clk_disable_unprepare,
> +				       clk);
> +	if (ret)
> +		return ERR_PTR(ret);
> +
> +	return clk;
> +}
> +
> +static int keembay_pcie_probe_clocks(struct keembay_pcie *pcie)
> +{
> +	struct dw_pcie *pci = pcie->pci;
> +	struct device *dev = pci->dev;
> +
> +	pcie->clk_master = keembay_pcie_probe_clock(dev, "master", 0);
> +	if (IS_ERR(pcie->clk_master))
> +		return dev_err_probe(dev, PTR_ERR(pcie->clk_master),
> +				     "Failed to enable master clock");
> +
> +	pcie->clk_aux = keembay_pcie_probe_clock(dev, "aux", AUX_CLK_RATE_HZ);
> +	if (IS_ERR(pcie->clk_aux))
> +		return dev_err_probe(dev, PTR_ERR(pcie->clk_aux),
> +				     "Failed to enable auxiliary clock");
> +
> +	return 0;
> +}
> +
> +static int keembay_pcie_add_pcie_port(struct keembay_pcie *pcie,
> +				      struct platform_device *pdev)
> +{
> +	struct dw_pcie *pci = pcie->pci;
> +	struct pcie_port *pp = &pci->pp;
> +	struct device *dev = &pdev->dev;
> +	u32 val;
> +	int ret;
> +
> +	pcie->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(pcie->reset))
> +		return PTR_ERR(pcie->reset);
> +
> +	ret = keembay_pcie_probe_clocks(pcie);
> +	if (ret)
> +		return ret;
> +
> +	/* Set SRAM bypass mode. */
> +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_PHY_CNTL);
> +	val |= PHY0_SRAM_BYPASS;
> +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_PHY_CNTL, val);
> +
> +	/* Set the PCIe controller to be a Root Complex. */
> +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_CFG, PCIE_DEVICE_TYPE);
> +
> +	ret = keembay_pcie_pll_init(pcie);
> +	if (ret)
> +		return ret;
> +
> +	/* Deassert PCIe subsystem power-on-reset. */
> +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_CFG);
> +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_CFG, val | PCIE_RSTN);

Doesn't EP mode need to do all this setup too?

> +
> +	keembay_ep_reset_deassert(pcie);
> +
> +	ret = keembay_pcie_setup_irq(pcie);
> +	if (ret)
> +		return ret;
> +
> +	pp->ops = &keembay_pcie_host_ops;
> +
> +	ret = dw_pcie_host_init(pp);
> +	if (ret) {
> +		keembay_ep_reset_assert(pcie);
> +		dev_err(dev, "Failed to initialize host: %d\n", ret);
> +	}
> +
> +	return ret;
> +}
> +
> +static int keembay_pcie_add_pcie_ep(struct keembay_pcie *pcie,
> +				    struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct dw_pcie *pci = pcie->pci;
> +	struct dw_pcie_ep *ep;
> +	struct resource *res;
> +	int ret;
> +
> +	ep = &pci->ep;
> +	ep->ops = &keembay_pcie_ep_ops;
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "addr_space");
> +	if (!res)
> +		return -EINVAL;
> +
> +	ep->phys_base = res->start;
> +	ep->addr_size = resource_size(res);
> +
> +	ret = keembay_pcie_setup_irq(pcie);

Both RC and EP mode call this. Should be done from a common spot 
(probe?).

> +	if (ret)
> +		return ret;
> +
> +	ret = dw_pcie_ep_init(ep);
> +	if (ret)
> +		dev_err(dev, "Failed to initialize endpoint: %d\n", ret);
> +
> +	return ret;
> +}
> +
> +static int keembay_pcie_probe(struct platform_device *pdev)
> +{
> +	const struct keembay_pcie_of_data *data;
> +	struct device *dev = &pdev->dev;
> +	struct keembay_pcie *pcie;
> +	struct dw_pcie *pci;
> +	enum dw_pcie_device_mode mode;
> +	int ret;
> +
> +	data = device_get_match_data(dev);
> +	if (!data)
> +		return -ENODEV;
> +
> +	mode = (enum dw_pcie_device_mode)data->mode;
> +
> +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> +	if (!pcie)
> +		return -ENOMEM;
> +
> +	pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
> +	if (!pci)
> +		return -ENOMEM;
> +
> +	pci->dev = dev;
> +	pci->ops = &keembay_pcie_ops;
> +
> +	pcie->pci = pci;
> +	pcie->mode = mode;
> +
> +	pcie->apb_base = devm_platform_ioremap_resource_byname(pdev, "apb");
> +	if (IS_ERR(pcie->apb_base))
> +		return PTR_ERR(pcie->apb_base);
> +
> +	pci->dbi_base = devm_platform_ioremap_resource_byname(pdev, "dbi");
> +	if (IS_ERR(pci->dbi_base))
> +		return PTR_ERR(pci->dbi_base);
> +
> +	/* DBI2 shadow register */
> +	pci->dbi_base2 = pci->dbi_base + PCIE_DBI2_MASK;

This should be a 'dbi2' reg entry in DT.

FYI, I'm working on moving that and 'dbi' setup into the core code.

> +
> +	platform_set_drvdata(pdev, pcie);
> +
> +	switch (pcie->mode) {
> +	case DW_PCIE_RC_TYPE:
> +		if (!IS_ENABLED(CONFIG_PCIE_KEEMBAY_HOST))
> +			return -ENODEV;
> +
> +		ret = keembay_pcie_add_pcie_port(pcie, pdev);
> +		if (ret < 0)
> +			return ret;
> +		break;
> +	case DW_PCIE_EP_TYPE:
> +		if (!IS_ENABLED(CONFIG_PCIE_KEEMBAY_EP))
> +			return -ENODEV;
> +
> +		ret = keembay_pcie_add_pcie_ep(pcie, pdev);
> +		if (ret < 0)
> +			return ret;
> +		break;
> +	default:
> +		dev_err(dev, "Invalid device type %d\n", pcie->mode);
> +		return -ENODEV;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct keembay_pcie_of_data keembay_pcie_rc_of_data = {
> +	.mode = DW_PCIE_RC_TYPE,
> +};
> +
> +static const struct keembay_pcie_of_data keembay_pcie_ep_of_data = {
> +	.mode = DW_PCIE_EP_TYPE,
> +};
> +
> +static const struct of_device_id keembay_pcie_of_match[] = {
> +	{
> +		.compatible = "intel,keembay-pcie",
> +		.data = &keembay_pcie_rc_of_data,
> +	},
> +	{
> +		.compatible = "intel,keembay-pcie-ep",
> +		.data = &keembay_pcie_ep_of_data,
> +	},
> +	{}
> +};
> +
> +static struct platform_driver keembay_pcie_driver = {
> +	.driver = {
> +		.name = "keembay-pcie",
> +		.of_match_table = keembay_pcie_of_match,
> +		.suppress_bind_attrs = true,
> +	},
> +	.probe  = keembay_pcie_probe,
> +};
> +builtin_platform_driver(keembay_pcie_driver);
> -- 
> 2.17.1
>

On Wed, Oct 28, 2020 at 09:22:47AM -0500, Rob Herring wrote:
> On Tue, Oct 27, 2020 at 02:00:11PM +0800, Wan Ahmad Zainie wrote:

...

> > +config PCIE_KEEMBAY_HOST
> > +	bool "Intel Keem Bay PCIe controller - Host mode"
> > +	depends on ARCH_KEEMBAY || (ARM64 && COMPILE_TEST)
> 
> Why only ARM64 for compile test?

It's just for consistency with other Keem Bay drivers which may or may not use
ARM64 specific call. Since DWC3 core PCI driver is used on many platforms and
is being tested on other architectures, I think it's fine. This glue driver is
for certain platform. But what I'm wondering now is if the existing glue code
for some other platform can be reused here.

> > +	depends on PCI && PCI_MSI_IRQ_DOMAIN
> > +	select PCIE_DW_HOST
> > +	select PCIE_KEEMBAY

Hi Rob.

Thanks for the review.

> -----Original Message-----
> From: Rob Herring <robh@kernel.org>
> Sent: Wednesday, October 28, 2020 10:23 PM
> To: Wan Mohamad, Wan Ahmad Zainie
> <wan.ahmad.zainie.wan.mohamad@intel.com>
> Cc: bhelgaas@google.com; lorenzo.pieralisi@arm.com; linux-
> pci@vger.kernel.org; devicetree@vger.kernel.org;
> andriy.shevchenko@linux.intel.com; mgross@linux.intel.com; Raja
> Subramanian, Lakshmi Bai <lakshmi.bai.raja.subramanian@intel.com>
> Subject: Re: [PATCH 2/2] PCI: keembay: Add support for Intel Keem Bay
> 
> On Tue, Oct 27, 2020 at 02:00:11PM +0800, Wan Ahmad Zainie wrote:
> > Add driver for Intel Keem Bay SoC PCIe controller. This controller is
> > based on DesignWare PCIe core.
> >
> > In root complex mode, only internal reference clock is possible for
> > Keem Bay A0. For Keem Bay B0, external reference clock can be used and
> > will be the default configuration. Currently, keembay_pcie_of_data
> > structure has one member. It will be expanded later to handle this
> > difference.
> >
> > Endpoint mode link initialization is handled by the boot firmware.
> >
> > Signed-off-by: Wan Ahmad Zainie
> > <wan.ahmad.zainie.wan.mohamad@intel.com>
> > Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > ---
> >  drivers/pci/controller/dwc/Kconfig        |  24 +
> >  drivers/pci/controller/dwc/Makefile       |   1 +
> >  drivers/pci/controller/dwc/pcie-keembay.c | 658
> > ++++++++++++++++++++++
> >  3 files changed, 683 insertions(+)
> >  create mode 100644 drivers/pci/controller/dwc/pcie-keembay.c
> >
> > diff --git a/drivers/pci/controller/dwc/Kconfig
> > b/drivers/pci/controller/dwc/Kconfig
> > index bc049865f8e0..694a1fcacb73 100644
> > --- a/drivers/pci/controller/dwc/Kconfig
> > +++ b/drivers/pci/controller/dwc/Kconfig
> > @@ -219,6 +219,30 @@ config PCIE_INTEL_GW
> >  	  The PCIe controller uses the DesignWare core plus Intel-specific
> >  	  hardware wrappers.
> >
> > +config PCIE_KEEMBAY
> > +	bool
> > +
> > +config PCIE_KEEMBAY_HOST
> > +	bool "Intel Keem Bay PCIe controller - Host mode"
> > +	depends on ARCH_KEEMBAY || (ARM64 && COMPILE_TEST)
> 
> Why only ARM64 for compile test?

Andy did response to this.
https://lore.kernel.org/linux-pci/20201028153454.GV4077@smile.fi.intel.com/

I did not receive it my mailbox, so I copy paste here, in case.

> 
> > +	depends on PCI && PCI_MSI_IRQ_DOMAIN
> > +	select PCIE_DW_HOST
> > +	select PCIE_KEEMBAY
> > +	help
> > +	  Say Y here to enable support for the PCIe controller in Keem Bay
> > +	  to work in host mode. This uses the DesignWare core.
> > +
> > +config PCIE_KEEMBAY_EP
> > +	bool "Intel Keem Bay PCIe controller - Endpoint mode"
> > +	depends on ARCH_KEEMBAY || (ARM64 && COMPILE_TEST)
> > +	depends on PCI && PCI_MSI_IRQ_DOMAIN
> > +	depends on PCI_ENDPOINT
> > +	select PCIE_DW_EP
> > +	select PCIE_KEEMBAY
> > +	help
> > +	  Say Y here to enable support for the PCIe controller in Keem Bay
> > +	  to work in endpoint mode. This uses the DesignWare core.
> > +
> >  config PCIE_KIRIN
> >  	depends on OF && (ARM64 || COMPILE_TEST)
> >  	bool "HiSilicon Kirin series SoCs PCIe controllers"
> > diff --git a/drivers/pci/controller/dwc/Makefile
> > b/drivers/pci/controller/dwc/Makefile
> > index a751553fa0db..95da2c62c426 100644
> > --- a/drivers/pci/controller/dwc/Makefile
> > +++ b/drivers/pci/controller/dwc/Makefile
> > @@ -14,6 +14,7 @@ obj-$(CONFIG_PCIE_QCOM) += pcie-qcom.o
> >  obj-$(CONFIG_PCIE_ARMADA_8K) += pcie-armada8k.o
> >  obj-$(CONFIG_PCIE_ARTPEC6) += pcie-artpec6.o
> >  obj-$(CONFIG_PCIE_INTEL_GW) += pcie-intel-gw.o
> > +obj-$(CONFIG_PCIE_KEEMBAY) += pcie-keembay.o
> >  obj-$(CONFIG_PCIE_KIRIN) += pcie-kirin.o
> >  obj-$(CONFIG_PCIE_HISI_STB) += pcie-histb.o
> >  obj-$(CONFIG_PCI_MESON) += pci-meson.o diff --git
> > a/drivers/pci/controller/dwc/pcie-keembay.c
> > b/drivers/pci/controller/dwc/pcie-keembay.c
> > new file mode 100644
> > index 000000000000..30401ef223ca
> > --- /dev/null
> > +++ b/drivers/pci/controller/dwc/pcie-keembay.c
> > @@ -0,0 +1,658 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * PCIe controller driver for Intel Keem Bay
> > + * Copyright (C) 2020 Intel Corporation  */
> > +
> > +#include <linux/bitfield.h>
> > +#include <linux/bits.h>
> > +#include <linux/clk.h>
> > +#include <linux/delay.h>
> > +#include <linux/err.h>
> > +#include <linux/gpio/consumer.h>
> > +#include <linux/init.h>
> > +#include <linux/iopoll.h>
> > +#include <linux/kernel.h>
> > +#include <linux/mod_devicetable.h>
> > +#include <linux/pci.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/property.h>
> > +
> > +#include "pcie-designware.h"
> > +
> > +/* PCIE_REGS_APB_SLV Registers */
> > +#define PCIE_REGS_PCIE_CFG		0x0004
> > +#define  PCIE_DEVICE_TYPE		BIT(8)
> > +#define  PCIE_RSTN			BIT(0)
> > +#define PCIE_REGS_PCIE_APP_CNTRL	0x0008
> > +#define  APP_LTSSM_ENABLE		BIT(0)
> > +
> > +#define PCIE_REGS_PCIE_INTR_ENABLE	0x0018
> > +#define  LBC_CII_EVENT_EN		BIT(18)
> > +#define PCIE_REGS_PCIE_INTR_FLAGS	0x001c
> > +#define PCIE_REGS_PCIE_ERR_INTR_ENABLE	0x0020
> > +#define  LINK_REQ_RST_EN		BIT(15)
> > +#define PCIE_REGS_PCIE_ERR_INTR_FLAGS	0x0024
> > +#define PCIE_REGS_INTERRUPT_ENABLE	0x0028
> > +#define  MSI_CTRL_INT_EN		BIT(8)
> > +#define  EDMA_INT_EN			GENMASK(7, 0)
> > +#define PCIE_REGS_INTERRUPT_STATUS	0x002c
> > +#define  MSI_CTRL_INT			BIT(8)
> > +
> > +#define PCIE_REGS_PCIE_SII_PM_STATE	0x00b0
> > +#define  SMLH_LINK_UP			BIT(19)
> > +#define  RDLH_LINK_UP			BIT(8)
> > +#define PCIE_REGS_PCIE_PHY_CNTL		0x0164
> > +#define  PHY0_SRAM_BYPASS		BIT(8)
> > +#define PCIE_REGS_PCIE_PHY_STAT		0x0168
> > +#define  PHY0_MPLLA_STATE		BIT(1)
> > +#define PCIE_REGS_LJPLL_STA		0x016c
> > +#define  LJPLL_LOCK			BIT(0)
> > +#define PCIE_REGS_LJPLL_CNTRL_0		0x0170
> > +#define  LJPLL_EN			BIT(29)
> > +#define  LJPLL_FOUT_EN			GENMASK(24, 21)
> > +#define PCIE_REGS_LJPLL_CNTRL_2		0x0178
> > +#define  LJPLL_REF_DIV			GENMASK(17, 12)
> > +#define  LJPLL_FB_DIV			GENMASK(11, 0)
> > +#define PCIE_REGS_LJPLL_CNTRL_3		0x017c
> > +#define  LJPLL_POST_DIV3A		GENMASK(24, 22)
> > +#define  LJPLL_POST_DIV2A		GENMASK(18, 16)
> > +
> > +#define PCIE_REGS_MEM_ACCESS_IRQ_ENABLE	0x0184
> > +#define  MEM_ACCESS_IRQ_ENABLE		GENMASK(31, 0)
> > +
> > +#define PCIE_DBI2_MASK		BIT(20)
> > +#define PERST_DELAY_US		1000
> > +#define AUX_CLK_RATE_HZ		24000000
> > +
> > +struct keembay_pcie {
> > +	struct dw_pcie		*pci;
> 
> Make this a struct, not a pointer. Then one less alloc.

I will fix in v2.

> 
> > +	void __iomem		*apb_base;
> > +	enum dw_pcie_device_mode mode;
> > +
> > +	int			irq;
> > +	int			ev_irq;
> > +	int			err_irq;
> > +	int			mem_access_irq;
> 
> There's no need to store the irq numbers forever.

I will fix this in v2.
Need to modify keembay_pcie_setup_irq().

> 
> > +
> > +	struct clk		*clk_master;
> > +	struct clk		*clk_aux;
> > +	struct gpio_desc	*reset;
> > +};
> > +
> > +struct keembay_pcie_of_data {
> > +	enum dw_pcie_device_mode mode;
> > +};
> > +
> > +static inline u32 keembay_pcie_readl(struct keembay_pcie *pcie, u32
> > +offset) {
> > +	return readl(pcie->apb_base + offset); }
> > +
> > +static inline void keembay_pcie_writel(struct keembay_pcie *pcie, u32
> offset,
> > +				       u32 value)
> > +{
> > +	writel(value, pcie->apb_base + offset); }
> > +
> > +static void keembay_ep_reset_assert(struct keembay_pcie *pcie) {
> > +	gpiod_set_value_cansleep(pcie->reset, 1);
> > +	usleep_range(PERST_DELAY_US, PERST_DELAY_US + 500); }
> > +
> > +static void keembay_ep_reset_deassert(struct keembay_pcie *pcie) {
> > +	/* Ensure that PERST has been asserted for at least 100ms */
> > +	msleep(100);
> > +
> > +	gpiod_set_value_cansleep(pcie->reset, 0);
> > +	usleep_range(PERST_DELAY_US, PERST_DELAY_US + 500); }
> > +
> > +static void keembay_pcie_ltssm_enable(struct keembay_pcie *pcie, bool
> > +enable) {
> > +	u32 val;
> > +
> > +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_APP_CNTRL);
> > +	if (enable)
> > +		val |= APP_LTSSM_ENABLE;
> > +	else
> > +		val &= ~APP_LTSSM_ENABLE;
> > +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_APP_CNTRL, val); }
> > +
> > +static int keembay_pcie_link_up(struct dw_pcie *pci) {
> > +	struct keembay_pcie *pcie = dev_get_drvdata(pci->dev);
> > +	u32 val, mask;
> > +
> > +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_SII_PM_STATE);
> > +	mask = SMLH_LINK_UP | RDLH_LINK_UP;
> > +
> > +	return !!((val & mask) == mask);
> > +}
> > +
> > +static int keembay_pcie_establish_link(struct dw_pcie *pci)
> 
> _start_link() to align with the ops name.

I will fix in v2.

> 
> > +{
> > +	return 0;
> 
> Shouldn't this call keembay_pcie_ltssm_enable?

Prior to changes in for-kernelci branch, start_link ops is
used for endpoint mode only. Since Keem Bay endpoint
initialization is done by boot firmware, I override this ops
to return 0.

> 
> > +}
> > +
> > +static void keembay_pcie_stop_link(struct dw_pcie *pci) {
> > +	struct keembay_pcie *pcie = dev_get_drvdata(pci->dev);
> > +
> > +	keembay_pcie_ltssm_enable(pcie, false); }
> > +
> > +static const struct dw_pcie_ops keembay_pcie_ops = {
> > +	.link_up	= keembay_pcie_link_up,
> > +	.start_link	= keembay_pcie_establish_link,
> > +	.stop_link	= keembay_pcie_stop_link,
> > +};
> > +
> > +/*
> > + * Initialize the internal PCIe PLL in Host mode.
> > + * See the following sections in Keem Bay data book,
> > + * (1) 6.4.6.1 PCIe Subsystem Example Initialization,
> > + * (2) 6.8 PCIe Low Jitter PLL for Ref Clk Generation.
> > + */
> > +static int keembay_pcie_pll_init(struct keembay_pcie *pcie) {
> > +	struct dw_pcie *pci = pcie->pci;
> > +	u32 val;
> > +	int ret;
> > +
> > +	val = FIELD_PREP(LJPLL_REF_DIV, 0) | FIELD_PREP(LJPLL_FB_DIV,
> 0x32);
> > +	keembay_pcie_writel(pcie, PCIE_REGS_LJPLL_CNTRL_2, val);
> > +
> > +	val = FIELD_PREP(LJPLL_POST_DIV3A, 0x2) |
> > +		FIELD_PREP(LJPLL_POST_DIV2A, 0x2);
> > +	keembay_pcie_writel(pcie, PCIE_REGS_LJPLL_CNTRL_3, val);
> > +
> > +	val = FIELD_PREP(LJPLL_EN, 0x1) | FIELD_PREP(LJPLL_FOUT_EN, 0xc);
> > +	keembay_pcie_writel(pcie, PCIE_REGS_LJPLL_CNTRL_0, val);
> > +
> > +	ret = readl_poll_timeout(pcie->apb_base + PCIE_REGS_LJPLL_STA,
> > +				 val, val & LJPLL_LOCK, 20,
> > +				 500 * USEC_PER_MSEC);
> > +	if (ret)
> > +		dev_err(pci->dev, "Low jitter PLL is not locked\n");
> > +
> > +	return ret;
> > +}
> > +
> > +static irqreturn_t keembay_pcie_irq_handler(int irq, void *arg) {
> > +	struct keembay_pcie *pcie = arg;
> > +	struct dw_pcie *pci = pcie->pci;
> > +	struct pcie_port *pp = &pci->pp;
> > +	u32 val, mask, status;
> > +
> > +	val = keembay_pcie_readl(pcie, PCIE_REGS_INTERRUPT_STATUS);
> > +	mask = keembay_pcie_readl(pcie, PCIE_REGS_INTERRUPT_ENABLE);
> > +
> > +	status = val & mask;
> > +	if (!status)
> > +		return IRQ_NONE;
> > +
> > +	if (status & MSI_CTRL_INT)
> > +		dw_handle_msi_irq(pp);
> > +
> > +	keembay_pcie_writel(pcie, PCIE_REGS_INTERRUPT_STATUS, status);
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static irqreturn_t keembay_pcie_ev_irq_handler(int irq, void *arg) {
> > +	struct keembay_pcie *pcie = arg;
> > +	u32 val, mask, status;
> > +
> > +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_INTR_FLAGS);
> > +	mask = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_INTR_ENABLE);
> > +
> > +	status = val & mask;
> > +	if (!status)
> > +		return IRQ_NONE;
> > +
> > +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_INTR_FLAGS, status);
> 
> Why an interrupt handler that doesn't do anything?

I will fix in v2, remove unused interrupt handler.

> 
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static irqreturn_t keembay_pcie_err_irq_handler(int irq, void *arg) {
> > +	struct keembay_pcie *pcie = arg;
> > +	u32 val, mask, status;
> > +
> > +	val = keembay_pcie_readl(pcie,
> PCIE_REGS_PCIE_ERR_INTR_FLAGS);
> > +	mask = keembay_pcie_readl(pcie,
> PCIE_REGS_PCIE_ERR_INTR_ENABLE);
> > +
> > +	status = val & mask;
> > +	if (!status)
> > +		return IRQ_NONE;
> > +
> > +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_ERR_INTR_FLAGS,
> status);
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static int keembay_pcie_setup_irq(struct keembay_pcie *pcie) {
> > +
> > +	struct dw_pcie *pci = pcie->pci;
> > +	struct device *dev = pci->dev;
> > +	struct platform_device *pdev = to_platform_device(dev);
> > +	int ret;
> > +
> > +	pcie->irq = platform_get_irq_byname(pdev, "intr");
> > +	if (pcie->irq < 0)
> > +		return pcie->irq;
> > +
> > +	pcie->ev_irq = platform_get_irq_byname(pdev, "ev_intr");
> > +	if (pcie->ev_irq < 0)
> > +		return pcie->ev_irq;
> > +
> > +	pcie->err_irq = platform_get_irq_byname(pdev, "err_intr");
> > +	if (pcie->err_irq < 0)
> > +		return pcie->err_irq;
> > +
> > +	if (pcie->mode == DW_PCIE_EP_TYPE) {
> > +		int irq;
> > +
> > +		irq = platform_get_irq_byname(pdev, "mem_access_intr");
> > +		if (irq < 0)
> > +			return irq;
> > +
> > +		pcie->mem_access_irq = irq;
> > +		return 0;
> > +	}
> > +
> > +	ret = devm_request_irq(dev, pcie->irq, keembay_pcie_irq_handler,
> > +			       IRQF_SHARED | IRQF_NO_THREAD, "pcie-intr",
> pcie);
> > +	if (ret) {
> > +		dev_err(dev, "Failed to request IRQ: %d\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	ret = devm_request_irq(dev, pcie->ev_irq,
> keembay_pcie_ev_irq_handler,
> > +			       0, "pcie-ev-intr", pcie);
> > +	if (ret) {
> > +		dev_err(dev, "Failed to request event IRQ: %d\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	ret = devm_request_irq(dev, pcie->err_irq,
> keembay_pcie_err_irq_handler,
> > +			       0, "pcie-err-intr", pcie);
> > +	if (ret)
> > +		dev_err(dev, "Failed to request error IRQ: %d\n", ret);
> > +
> > +	return ret;
> > +}
> > +
> > +static int keembay_pcie_rc_establish_link(struct dw_pcie *pci) {
> > +	struct keembay_pcie *pcie = dev_get_drvdata(pci->dev);
> > +	u32 val;
> > +	int ret;
> > +
> > +	if (dw_pcie_link_up(pci))
> > +		return 0;
> > +
> > +	keembay_pcie_ltssm_enable(pcie, false);
> > +
> > +	ret = readl_poll_timeout(pcie->apb_base +
> PCIE_REGS_PCIE_PHY_STAT,
> > +				 val, val & PHY0_MPLLA_STATE, 20,
> > +				 500 * USEC_PER_MSEC);
> > +	if (ret) {
> > +		dev_err(pci->dev, "MPLLA is not locked\n");
> > +		return ret;
> > +	}
> > +
> > +	keembay_pcie_ltssm_enable(pcie, true);
> > +
> > +	return dw_pcie_wait_for_link(pci);
> > +}
> > +
> > +static void keembay_pcie_enable_interrupts(struct keembay_pcie *pcie)
> > +{
> > +	u32 val;
> > +
> > +	/* Enable interrupt */
> > +	val = keembay_pcie_readl(pcie, PCIE_REGS_INTERRUPT_ENABLE);
> > +
> > +	if (IS_ENABLED(CONFIG_PCI_MSI))
> > +		val |= MSI_CTRL_INT_EN;
> > +
> > +	keembay_pcie_writel(pcie, PCIE_REGS_INTERRUPT_ENABLE, val);
> > +
> > +	/* Enable event interrupt */
> > +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_INTR_ENABLE);
> > +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_INTR_ENABLE, val);
> > +
> > +	/* Enable error interrupt */
> > +	val = keembay_pcie_readl(pcie,
> PCIE_REGS_PCIE_ERR_INTR_ENABLE);
> > +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_ERR_INTR_ENABLE,
> val); }
> > +
> > +static int __init keembay_pcie_host_init(struct pcie_port *pp) {
> > +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> > +	struct keembay_pcie *pcie = dev_get_drvdata(pci->dev);
> > +	int ret;
> > +
> > +	dw_pcie_setup_rc(pp);
> > +	ret = keembay_pcie_rc_establish_link(pci);
> > +	if (ret)
> > +		return ret;
> > +
> > +	if (IS_ENABLED(CONFIG_PCI_MSI))
> > +		dw_pcie_msi_init(pp);
> > +
> > +	keembay_pcie_enable_interrupts(pcie);
> > +
> > +	/* Disable BARs */
> 
> Why? I don't see other DWC drivers doing this.

Looks like it is a Keem Bay specific requirement.

It is specified in Keem Bay data book [1]. I quote Section 6.4.9.3.2,
"As BAR0 is configured to have its incoming requests routed to TRGT0 in EP mode,
then you must disable that BAR (through a DBI write) when operating the controller
in RC mode."

[1] https://cdrdv2.intel.com/v1/dl/getContent/615086

> 
> > +	dw_pcie_dbi_ro_wr_en(pci);
> > +	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0 | PCIE_DBI2_MASK,
> 0);
> > +	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_1 | PCIE_DBI2_MASK,
> 0);
> > +	dw_pcie_dbi_ro_wr_dis(pci);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct dw_pcie_host_ops keembay_pcie_host_ops = {
> > +	.host_init	= keembay_pcie_host_init,
> > +};
> > +
> > +static void keembay_pcie_ep_init(struct dw_pcie_ep *ep) {
> > +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > +	struct keembay_pcie *pcie = dev_get_drvdata(pci->dev);
> > +	u32 val;
> > +
> > +	/* Enable DMA completion/error interrupts */
> > +	val = keembay_pcie_readl(pcie, PCIE_REGS_INTERRUPT_ENABLE);
> > +	keembay_pcie_writel(pcie, PCIE_REGS_INTERRUPT_ENABLE,
> > +			    val | EDMA_INT_EN);
> > +
> > +	/* Enable CII event interrupt */
> > +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_INTR_ENABLE);
> > +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_INTR_ENABLE,
> > +			    val | LBC_CII_EVENT_EN);
> > +
> > +	/* Enable link request reset */
> > +	val = keembay_pcie_readl(pcie,
> PCIE_REGS_PCIE_ERR_INTR_ENABLE);
> > +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_ERR_INTR_ENABLE,
> > +			    val | LINK_REQ_RST_EN);
> > +
> > +	/* Enable host memory access interrupt */
> > +	keembay_pcie_writel(pcie, PCIE_REGS_MEM_ACCESS_IRQ_ENABLE,
> > +			    MEM_ACCESS_IRQ_ENABLE);
> > +}
> > +
> > +static int keembay_pcie_ep_raise_irq(struct dw_pcie_ep *ep, u8
> func_no,
> > +				     enum pci_epc_irq_type type,
> > +				     u16 interrupt_num)
> > +{
> > +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > +
> > +	switch (type) {
> > +	case PCI_EPC_IRQ_LEGACY:
> > +		/* Legacy interrupts are not supported in Keem Bay */
> > +		dev_err(pci->dev, "Unsupported IRQ type\n");
> > +		return -EINVAL;
> > +	case PCI_EPC_IRQ_MSI:
> > +		return dw_pcie_ep_raise_msi_irq(ep, func_no,
> interrupt_num);
> > +	case PCI_EPC_IRQ_MSIX:
> > +		return dw_pcie_ep_raise_msix_irq(ep, func_no,
> interrupt_num);
> > +	default:
> > +		dev_err(pci->dev, "Unknown IRQ type\n");
> > +		return -EINVAL;
> > +	}
> > +}
> > +
> > +static const struct pci_epc_features keembay_pcie_epc_features = {
> > +	.linkup_notifier	= false,
> > +	.msi_capable		= true,
> > +	.msix_capable		= true,
> > +	.reserved_bar		= BIT(BAR_1) | BIT(BAR_3) | BIT(BAR_5),
> > +	.bar_fixed_64bit	= BIT(BAR_0) | BIT(BAR_2) | BIT(BAR_4),
> > +	.align			= SZ_16K,
> > +};
> > +
> > +static const struct pci_epc_features *
> > +keembay_pcie_get_features(struct dw_pcie_ep *ep) {
> > +	return &keembay_pcie_epc_features;
> > +}
> > +
> > +static const struct dw_pcie_ep_ops keembay_pcie_ep_ops = {
> > +	.ep_init	= keembay_pcie_ep_init,
> > +	.raise_irq	= keembay_pcie_ep_raise_irq,
> > +	.get_features	= keembay_pcie_get_features,
> > +};
> > +
> > +static inline struct clk *keembay_pcie_probe_clock(struct device *dev,
> > +						   const char *id, u64 rate)
> > +{
> > +	struct clk *clk;
> > +	int ret;
> > +
> > +	clk = devm_clk_get(dev, id);
> > +	if (IS_ERR(clk))
> > +		return clk;
> > +
> > +	if (rate) {
> > +		ret = clk_set_rate(clk, rate);
> > +		if (ret)
> > +			return ERR_PTR(ret);
> > +	}
> > +
> > +	ret = clk_prepare_enable(clk);
> > +	if (ret)
> > +		return ERR_PTR(ret);
> > +
> > +	ret = devm_add_action_or_reset(dev,
> > +				       (void(*)(void *))clk_disable_unprepare,
> > +				       clk);
> > +	if (ret)
> > +		return ERR_PTR(ret);
> > +
> > +	return clk;
> > +}
> > +
> > +static int keembay_pcie_probe_clocks(struct keembay_pcie *pcie) {
> > +	struct dw_pcie *pci = pcie->pci;
> > +	struct device *dev = pci->dev;
> > +
> > +	pcie->clk_master = keembay_pcie_probe_clock(dev, "master", 0);
> > +	if (IS_ERR(pcie->clk_master))
> > +		return dev_err_probe(dev, PTR_ERR(pcie->clk_master),
> > +				     "Failed to enable master clock");
> > +
> > +	pcie->clk_aux = keembay_pcie_probe_clock(dev, "aux",
> AUX_CLK_RATE_HZ);
> > +	if (IS_ERR(pcie->clk_aux))
> > +		return dev_err_probe(dev, PTR_ERR(pcie->clk_aux),
> > +				     "Failed to enable auxiliary clock");
> > +
> > +	return 0;
> > +}
> > +
> > +static int keembay_pcie_add_pcie_port(struct keembay_pcie *pcie,
> > +				      struct platform_device *pdev) {
> > +	struct dw_pcie *pci = pcie->pci;
> > +	struct pcie_port *pp = &pci->pp;
> > +	struct device *dev = &pdev->dev;
> > +	u32 val;
> > +	int ret;
> > +
> > +	pcie->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> > +	if (IS_ERR(pcie->reset))
> > +		return PTR_ERR(pcie->reset);
> > +
> > +	ret = keembay_pcie_probe_clocks(pcie);
> > +	if (ret)
> > +		return ret;
> > +
> > +	/* Set SRAM bypass mode. */
> > +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_PHY_CNTL);
> > +	val |= PHY0_SRAM_BYPASS;
> > +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_PHY_CNTL, val);
> > +
> > +	/* Set the PCIe controller to be a Root Complex. */
> > +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_CFG,
> PCIE_DEVICE_TYPE);
> > +
> > +	ret = keembay_pcie_pll_init(pcie);
> > +	if (ret)
> > +		return ret;
> > +
> > +	/* Deassert PCIe subsystem power-on-reset. */
> > +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_CFG);
> > +	keembay_pcie_writel(pcie, PCIE_REGS_PCIE_CFG, val | PCIE_RSTN);
> 
> Doesn't EP mode need to do all this setup too?

For Keem Bay, endpoint mode link initialization should be done by
boot firmware.

> 
> > +
> > +	keembay_ep_reset_deassert(pcie);
> > +
> > +	ret = keembay_pcie_setup_irq(pcie);
> > +	if (ret)
> > +		return ret;
> > +
> > +	pp->ops = &keembay_pcie_host_ops;
> > +
> > +	ret = dw_pcie_host_init(pp);
> > +	if (ret) {
> > +		keembay_ep_reset_assert(pcie);
> > +		dev_err(dev, "Failed to initialize host: %d\n", ret);
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> > +static int keembay_pcie_add_pcie_ep(struct keembay_pcie *pcie,
> > +				    struct platform_device *pdev) {
> > +	struct device *dev = &pdev->dev;
> > +	struct dw_pcie *pci = pcie->pci;
> > +	struct dw_pcie_ep *ep;
> > +	struct resource *res;
> > +	int ret;
> > +
> > +	ep = &pci->ep;
> > +	ep->ops = &keembay_pcie_ep_ops;
> > +
> > +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> "addr_space");
> > +	if (!res)
> > +		return -EINVAL;
> > +
> > +	ep->phys_base = res->start;
> > +	ep->addr_size = resource_size(res);
> > +
> > +	ret = keembay_pcie_setup_irq(pcie);
> 
> Both RC and EP mode call this. Should be done from a common spot
> (probe?).

I will fix in v2, call keembay_pcie_setup_irq() from probe().

> 
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = dw_pcie_ep_init(ep);
> > +	if (ret)
> > +		dev_err(dev, "Failed to initialize endpoint: %d\n", ret);
> > +
> > +	return ret;
> > +}
> > +
> > +static int keembay_pcie_probe(struct platform_device *pdev) {
> > +	const struct keembay_pcie_of_data *data;
> > +	struct device *dev = &pdev->dev;
> > +	struct keembay_pcie *pcie;
> > +	struct dw_pcie *pci;
> > +	enum dw_pcie_device_mode mode;
> > +	int ret;
> > +
> > +	data = device_get_match_data(dev);
> > +	if (!data)
> > +		return -ENODEV;
> > +
> > +	mode = (enum dw_pcie_device_mode)data->mode;
> > +
> > +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> > +	if (!pcie)
> > +		return -ENOMEM;
> > +
> > +	pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
> > +	if (!pci)
> > +		return -ENOMEM;
> > +
> > +	pci->dev = dev;
> > +	pci->ops = &keembay_pcie_ops;
> > +
> > +	pcie->pci = pci;
> > +	pcie->mode = mode;
> > +
> > +	pcie->apb_base =
> devm_platform_ioremap_resource_byname(pdev, "apb");
> > +	if (IS_ERR(pcie->apb_base))
> > +		return PTR_ERR(pcie->apb_base);
> > +
> > +	pci->dbi_base = devm_platform_ioremap_resource_byname(pdev,
> "dbi");
> > +	if (IS_ERR(pci->dbi_base))
> > +		return PTR_ERR(pci->dbi_base);
> > +
> > +	/* DBI2 shadow register */
> > +	pci->dbi_base2 = pci->dbi_base + PCIE_DBI2_MASK;
> 
> This should be a 'dbi2' reg entry in DT.
> 
> FYI, I'm working on moving that and 'dbi' setup into the core code.

Noted. I did take a look into for-kernelci branch.

I need advice on how I should move forward.
Should I rebase my changes to for-kernelci or mainline branch?

> 
> > +
> > +	platform_set_drvdata(pdev, pcie);
> > +
> > +	switch (pcie->mode) {
> > +	case DW_PCIE_RC_TYPE:
> > +		if (!IS_ENABLED(CONFIG_PCIE_KEEMBAY_HOST))
> > +			return -ENODEV;
> > +
> > +		ret = keembay_pcie_add_pcie_port(pcie, pdev);
> > +		if (ret < 0)
> > +			return ret;
> > +		break;
> > +	case DW_PCIE_EP_TYPE:
> > +		if (!IS_ENABLED(CONFIG_PCIE_KEEMBAY_EP))
> > +			return -ENODEV;
> > +
> > +		ret = keembay_pcie_add_pcie_ep(pcie, pdev);
> > +		if (ret < 0)
> > +			return ret;
> > +		break;
> > +	default:
> > +		dev_err(dev, "Invalid device type %d\n", pcie->mode);
> > +		return -ENODEV;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct keembay_pcie_of_data keembay_pcie_rc_of_data = {
> > +	.mode = DW_PCIE_RC_TYPE,
> > +};
> > +
> > +static const struct keembay_pcie_of_data keembay_pcie_ep_of_data = {
> > +	.mode = DW_PCIE_EP_TYPE,
> > +};
> > +
> > +static const struct of_device_id keembay_pcie_of_match[] = {
> > +	{
> > +		.compatible = "intel,keembay-pcie",
> > +		.data = &keembay_pcie_rc_of_data,
> > +	},
> > +	{
> > +		.compatible = "intel,keembay-pcie-ep",
> > +		.data = &keembay_pcie_ep_of_data,
> > +	},
> > +	{}
> > +};
> > +
> > +static struct platform_driver keembay_pcie_driver = {
> > +	.driver = {
> > +		.name = "keembay-pcie",
> > +		.of_match_table = keembay_pcie_of_match,
> > +		.suppress_bind_attrs = true,
> > +	},
> > +	.probe  = keembay_pcie_probe,
> > +};
> > +builtin_platform_driver(keembay_pcie_driver);
> > --
> > 2.17.1
> >

Best regards,
Zainie

On Tue, Oct 27, 2020 at 02:00:11PM +0800, Wan Ahmad Zainie wrote:

> +static int keembay_pcie_link_up(struct dw_pcie *pci)
> +{
> +	struct keembay_pcie *pcie = dev_get_drvdata(pci->dev);
> +	u32 val, mask;
> +
> +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_SII_PM_STATE);
> +	mask = SMLH_LINK_UP | RDLH_LINK_UP;
> +
> +	return !!((val & mask) == mask);

I think the "!!" is redundant since you're applying it to a value
that's a boolean already.  So you should be able to do:

  return (val & mask) == mask;

But it seems like "mask" just obfuscates a little bit, too.
Personally I think it'd be easier to add something like:

  #define PCIE_REGS_PCIE_SII_LINK_UP  (SMLH_LINK_UP | RDLH_LINK_UP)

and then:

  if ((val & PCIE_REGS_PCIE_SII_LINK_UP) == PCIE_REGS_PCIE_SII_LINK_UP)
    return 1;
  return 0;

or even:

  return (val & PCIE_REGS_PCIE_SII_LINK_UP) == PCIE_REGS_PCIE_SII_LINK_UP;

> +static int keembay_pcie_establish_link(struct dw_pcie *pci)
> +{
> +	return 0;
> +}

Are you sure you need this?  I see other cases where the .start_link
pointer is left NULL, e.g., pci-exynos.c, pci-imx6.c,
dw_ls1021_pcie_ops, etc.

> +static int keembay_pcie_ep_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
> +				     enum pci_epc_irq_type type,
> +				     u16 interrupt_num)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> +
> +	switch (type) {
> +	case PCI_EPC_IRQ_LEGACY:
> +		/* Legacy interrupts are not supported in Keem Bay */
> +		dev_err(pci->dev, "Unsupported IRQ type\n");

Might be nice to mention "legacy" here.

> +		return -EINVAL;
> +	case PCI_EPC_IRQ_MSI:
> +		return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
> +	case PCI_EPC_IRQ_MSIX:
> +		return dw_pcie_ep_raise_msix_irq(ep, func_no, interrupt_num);
> +	default:
> +		dev_err(pci->dev, "Unknown IRQ type\n");

And maybe include the %d of "type"?

On Tue, Nov 03, 2020 at 04:22:23PM -0600, Bjorn Helgaas wrote:
> On Tue, Oct 27, 2020 at 02:00:11PM +0800, Wan Ahmad Zainie wrote:
> > +static int keembay_pcie_link_up(struct dw_pcie *pci)
> > +{
> > +	struct keembay_pcie *pcie = dev_get_drvdata(pci->dev);
> > +	u32 val, mask;
> > +
> > +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_SII_PM_STATE);
> > +	mask = SMLH_LINK_UP | RDLH_LINK_UP;
> > +
> > +	return !!((val & mask) == mask);
> 
> I think the "!!" is redundant since you're applying it to a value
> that's a boolean already.  So you should be able to do:
> 
>   return (val & mask) == mask;
> 
> But it seems like "mask" just obfuscates a little bit, too.
> Personally I think it'd be easier to add something like:
> 
>   #define PCIE_REGS_PCIE_SII_LINK_UP  (SMLH_LINK_UP | RDLH_LINK_UP)
> 
> and then:

>   if ((val & PCIE_REGS_PCIE_SII_LINK_UP) == PCIE_REGS_PCIE_SII_LINK_UP)
>     return 1;
>   return 0;

The !! is usual way to guarantee that *int* type out of boolean will be only
0 or 1. That said, the above proposal suits better.

> or even:
> 
>   return (val & PCIE_REGS_PCIE_SII_LINK_UP) == PCIE_REGS_PCIE_SII_LINK_UP;

> -----Original Message-----
> From: Bjorn Helgaas <helgaas@kernel.org>
> Sent: Wednesday, November 4, 2020 6:22 AM
> To: Wan Mohamad, Wan Ahmad Zainie
> <wan.ahmad.zainie.wan.mohamad@intel.com>
> Cc: bhelgaas@google.com; robh+dt@kernel.org; lorenzo.pieralisi@arm.com;
> linux-pci@vger.kernel.org; devicetree@vger.kernel.org;
> andriy.shevchenko@linux.intel.com; mgross@linux.intel.com; Raja
> Subramanian, Lakshmi Bai <lakshmi.bai.raja.subramanian@intel.com>
> Subject: Re: [PATCH 2/2] PCI: keembay: Add support for Intel Keem Bay
> 
> On Tue, Oct 27, 2020 at 02:00:11PM +0800, Wan Ahmad Zainie wrote:
> 
> > +static int keembay_pcie_link_up(struct dw_pcie *pci) {
> > +	struct keembay_pcie *pcie = dev_get_drvdata(pci->dev);
> > +	u32 val, mask;
> > +
> > +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_SII_PM_STATE);
> > +	mask = SMLH_LINK_UP | RDLH_LINK_UP;
> > +
> > +	return !!((val & mask) == mask);
> 
> I think the "!!" is redundant since you're applying it to a value that's a boolean
> already.  So you should be able to do:
> 
>   return (val & mask) == mask;
> 
> But it seems like "mask" just obfuscates a little bit, too.
> Personally I think it'd be easier to add something like:
> 
>   #define PCIE_REGS_PCIE_SII_LINK_UP  (SMLH_LINK_UP | RDLH_LINK_UP)
> 
> and then:
> 
>   if ((val & PCIE_REGS_PCIE_SII_LINK_UP) == PCIE_REGS_PCIE_SII_LINK_UP)
>     return 1;
>   return 0;

I will fix in v2, using the above as agreed by Andy.

> 
> or even:
> 
>   return (val & PCIE_REGS_PCIE_SII_LINK_UP) ==
> PCIE_REGS_PCIE_SII_LINK_UP;
> 
> > +static int keembay_pcie_establish_link(struct dw_pcie *pci) {
> > +	return 0;
> > +}
> 
> Are you sure you need this?  I see other cases where the .start_link pointer is
> left NULL, e.g., pci-exynos.c, pci-imx6.c, dw_ls1021_pcie_ops, etc.

Yes, as in endpoint mode, link initialization is done in boot firmware.
Leaving it NULL will cause pcie-designware-ep.c::dw_pcie_ep_start()
to return -EINVAL.

Rob is refactoring DWC code and looks like .start_link is used in root complex
mode too. I will make changes to above function in v2, by renaming to
keembay_pci2_start_link and add link initialization code for root complex
mode.

> 
> > +static int keembay_pcie_ep_raise_irq(struct dw_pcie_ep *ep, u8
> func_no,
> > +				     enum pci_epc_irq_type type,
> > +				     u16 interrupt_num)
> > +{
> > +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > +
> > +	switch (type) {
> > +	case PCI_EPC_IRQ_LEGACY:
> > +		/* Legacy interrupts are not supported in Keem Bay */
> > +		dev_err(pci->dev, "Unsupported IRQ type\n");
> 
> Might be nice to mention "legacy" here.

I will fix in v2, using string "Legacy IRQ is not supported".

> 
> > +		return -EINVAL;
> > +	case PCI_EPC_IRQ_MSI:
> > +		return dw_pcie_ep_raise_msi_irq(ep, func_no,
> interrupt_num);
> > +	case PCI_EPC_IRQ_MSIX:
> > +		return dw_pcie_ep_raise_msix_irq(ep, func_no,
> interrupt_num);
> > +	default:
> > +		dev_err(pci->dev, "Unknown IRQ type\n");
> 
> And maybe include the %d of "type"?

I will fix in v2, to show the value of "type".

Best regards,
Zainie