[v5,2/5] pci:host: Add Altera PCIe host controller driver

This patch adds the Altera PCIe host controller driver.

Signed-off-by: Ley Foon Tan <lftan@altera.com>
---
 drivers/pci/host/Kconfig       |   7 +
 drivers/pci/host/Makefile      |   1 +
 drivers/pci/host/pcie-altera.c | 588 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 596 insertions(+)
 create mode 100644 drivers/pci/host/pcie-altera.c

On 25/08/15 10:35, Ley Foon Tan wrote:
> This patch adds the Altera PCIe host controller driver.
> 
> Signed-off-by: Ley Foon Tan <lftan@altera.com>
> ---
>  drivers/pci/host/Kconfig       |   7 +
>  drivers/pci/host/Makefile      |   1 +
>  drivers/pci/host/pcie-altera.c | 588 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 596 insertions(+)
>  create mode 100644 drivers/pci/host/pcie-altera.c
> 
> diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
> index 675c2d1..4b4754a 100644
> --- a/drivers/pci/host/Kconfig
> +++ b/drivers/pci/host/Kconfig
> @@ -145,4 +145,11 @@ config PCIE_IPROC_BCMA
>  	  Say Y here if you want to use the Broadcom iProc PCIe controller
>  	  through the BCMA bus interface
>  
> +config PCIE_ALTERA
> +	tristate "Altera PCIe controller"
> +	depends on ARCH_SOCFPGA
> +	help
> +	  Say Y here if you want to enable PCIe controller support for Altera
> +	  SoCFPGA family of SoCs.
> +
>  endmenu
> diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
> index 140d66f..6954f76 100644
> --- a/drivers/pci/host/Makefile
> +++ b/drivers/pci/host/Makefile
> @@ -17,3 +17,4 @@ obj-$(CONFIG_PCI_VERSATILE) += pci-versatile.o
>  obj-$(CONFIG_PCIE_IPROC) += pcie-iproc.o
>  obj-$(CONFIG_PCIE_IPROC_PLATFORM) += pcie-iproc-platform.o
>  obj-$(CONFIG_PCIE_IPROC_BCMA) += pcie-iproc-bcma.o
> +obj-$(CONFIG_PCIE_ALTERA) += pcie-altera.o
> diff --git a/drivers/pci/host/pcie-altera.c b/drivers/pci/host/pcie-altera.c
> new file mode 100644
> index 0000000..c168ec7
> --- /dev/null
> +++ b/drivers/pci/host/pcie-altera.c
> @@ -0,0 +1,588 @@
> +/*
> + * Copyright Altera Corporation (C) 2013-2015. All rights reserved
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/irqchip/chained_irq.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_pci.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +#define A2P_ADDR_MAP_LO0		0x1000
> +#define A2P_ADDR_MAP_HI0		0x1004
> +#define RP_TX_REG0			0x2000
> +#define RP_TX_REG1			0x2004
> +#define RP_TX_CNTRL			0x2008
> +#define RP_TX_EOP			0x2
> +#define RP_TX_SOP			0x1
> +#define RP_RXCPL_STATUS		0x2010
> +#define RP_RXCPL_EOP			0x2
> +#define RP_RXCPL_SOP			0x1
> +#define RP_RXCPL_REG0			0x2014
> +#define RP_RXCPL_REG1			0x2018
> +#define P2A_INT_STATUS			0x3060
> +#define P2A_INT_STS_ALL			0xF
> +#define P2A_INT_ENABLE			0x3070
> +#define P2A_INT_ENA_ALL			0xF
> +#define RP_LTSSM			0x3C64
> +#define LTSSM_L0			0xF
> +
> +/* TLP configuration type 0 and 1 */
> +#define TLP_FMTTYPE_CFGRD0		0x04	/* Configuration Read Type 0 */
> +#define TLP_FMTTYPE_CFGWR0		0x44	/* Configuration Write Type 0 */
> +#define TLP_FMTTYPE_CFGRD1		0x05	/* Configuration Read Type 1 */
> +#define TLP_FMTTYPE_CFGWR1		0x45	/* Configuration Write Type 1 */
> +#define TLP_PAYLOAD_SIZE		0x01
> +#define TLP_READ_TAG			0x1D
> +#define TLP_WRITE_TAG			0x10
> +#define TLP_CFG_DW0(fmttype)		(((fmttype) << 24) | TLP_PAYLOAD_SIZE)
> +#define TLP_CFG_DW1(reqid, tag)		(((reqid) << 16) | (tag << 8) | 0xF)
> +#define TLP_CFG_DW2(bus, devfn, offset)	\
> +				(((bus) << 24) | ((devfn) << 16) | (offset))
> +#define TLP_REQ_ID(bus, devfn)		(((bus) << 8) | (devfn))
> +#define TLP_COMPL_STATUS(hdr)		(((hdr) & 0xE0) >> 13)
> +#define TLP_HDR_SIZE			3
> +#define TLP_LOOP			10
> +
> +#define INTX_NUM		4
> +
> +/* Address translation table entry size */
> +#define ATT_ENTRY_SIZE		8
> +
> +#define DWORD_MASK		3
> +
> +struct altera_pcie {
> +	struct platform_device	*pdev;
> +	void __iomem		*cra_base;
> +	int			irq;
> +	u8			root_bus_nr;
> +	struct irq_domain		*irq_domain;
> +	struct resource		bus_range;
> +	struct list_head		resources;
> +};
> +
> +struct tlp_rp_regpair_t {
> +	u32 ctrl;
> +	u32 reg0;
> +	u32 reg1;
> +};
> +
> +static void altera_pcie_retrain(struct pci_dev *dev)
> +{
> +	u16 linkcap, linkstat;
> +
> +	/*
> +	 * Set the retrain bit if the PCIe rootport support > 2.5GB/s, but
> +	 * current speed is 2.5 GB/s.
> +	 */
> +	pcie_capability_read_word(dev, PCI_EXP_LNKCAP, &linkcap);
> +
> +	if ((linkcap & PCI_EXP_LNKCAP_SLS) <= PCI_EXP_LNKCAP_SLS_2_5GB)
> +		return;
> +
> +	pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &linkstat);
> +	if ((linkstat & PCI_EXP_LNKSTA_CLS) == PCI_EXP_LNKSTA_CLS_2_5GB)
> +		pcie_capability_set_word(dev, PCI_EXP_LNKCTL,
> +					 PCI_EXP_LNKCTL_RL);
> +}
> +DECLARE_PCI_FIXUP_EARLY(PCI_ANY_ID, PCI_ANY_ID, altera_pcie_retrain);

Do I read this correctly? This function is being called on any PCI
device, without any filtering? What if the platform is not using this
driver despite the driver being compiled in?

> +
> +static void altera_pcie_fixup_res(struct pci_dev *dev)
> +{
> +	/*
> +	 * Prevent enumeration of root port.
> +	 */
> +	if (!dev->bus->parent && dev->devfn == 0) {
> +		int i;
> +
> +		for (i = 0; i < PCI_NUM_RESOURCES; i++) {
> +			dev->resource[i].start = 0;
> +			dev->resource[i].end   = 0;
> +			dev->resource[i].flags   = 0;
> +		}
> +	}
> +}
> +DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, altera_pcie_fixup_res);

Same here. I also question the validity of nuking the resources, but I'm
not a PCI expert.

> +
> +static inline void cra_writel(struct altera_pcie *pcie, u32 value, u32 reg)
> +{
> +	writel_relaxed(value, pcie->cra_base + reg);
> +}
> +
> +static inline u32 cra_readl(struct altera_pcie *pcie, u32 reg)
> +{
> +	return readl_relaxed(pcie->cra_base + reg);
> +}
> +
> +static void tlp_read_rx(struct altera_pcie *pcie,
> +			struct tlp_rp_regpair_t *tlp_rp_regdata)
> +{
> +	tlp_rp_regdata->ctrl = cra_readl(pcie, RP_RXCPL_STATUS);
> +	tlp_rp_regdata->reg0 = cra_readl(pcie, RP_RXCPL_REG0);
> +	tlp_rp_regdata->reg1 = cra_readl(pcie, RP_RXCPL_REG1);
> +}
> +
> +static void tlp_write_tx(struct altera_pcie *pcie,
> +			 struct tlp_rp_regpair_t *tlp_rp_regdata)
> +{
> +	cra_writel(pcie, tlp_rp_regdata->reg0, RP_TX_REG0);
> +	cra_writel(pcie, tlp_rp_regdata->reg1, RP_TX_REG1);
> +	cra_writel(pcie, tlp_rp_regdata->ctrl, RP_TX_CNTRL);
> +}
> +
> +static bool altera_pcie_link_is_up(struct altera_pcie *pcie)
> +{
> +	return !!(cra_readl(pcie, RP_LTSSM) & LTSSM_L0);
> +}
> +
> +static bool altera_pcie_valid_config(struct altera_pcie *pcie,
> +				     struct pci_bus *bus, int dev)
> +{
> +	/* If there is no link, then there is no device */
> +	if (bus->number != pcie->root_bus_nr) {
> +		if (!altera_pcie_link_is_up(pcie))
> +			return false;
> +	}
> +
> +	/* access only one slot on each root port */
> +	if (bus->number == pcie->root_bus_nr && dev > 0)
> +		return false;
> +
> +	/*
> +	 * Do not read more than one device on the bus directly attached
> +	 * to RC.
> +	 */
> +	if (bus->primary == pcie->root_bus_nr && dev > 0)
> +		return false;
> +
> +	 return true;
> +}
> +
> +static int tlp_read_packet(struct altera_pcie *pcie, u32 *value)
> +{
> +	u8 loop;
> +	struct tlp_rp_regpair_t tlp_rp_regdata;
> +
> +	for (loop = 0; loop < TLP_LOOP; loop++) {
> +		tlp_read_rx(pcie, &tlp_rp_regdata);
> +		if (tlp_rp_regdata.ctrl & RP_RXCPL_EOP) {
> +			if (value)
> +				*value = tlp_rp_regdata.reg0;
> +			return PCIBIOS_SUCCESSFUL;
> +		}
> +		udelay(5);
> +	}
> +
> +	return -ENOENT;
> +}
> +
> +static void tlp_write_packet_unaligned(struct altera_pcie *pcie, u32 *headers,
> +				       u32 data)
> +{
> +	struct tlp_rp_regpair_t tlp_rp_regdata;
> +
> +	tlp_rp_regdata.reg0 = headers[0];
> +	tlp_rp_regdata.reg1 = headers[1];
> +	tlp_rp_regdata.ctrl = RP_TX_SOP;
> +	tlp_write_tx(pcie, &tlp_rp_regdata);
> +
> +	tlp_rp_regdata.reg0 = headers[2];
> +	tlp_rp_regdata.reg1 = data;
> +	tlp_rp_regdata.ctrl = RP_TX_EOP;
> +	tlp_write_tx(pcie, &tlp_rp_regdata);
> +}
> +
> +static void tlp_write_packet_aligned(struct altera_pcie *pcie, u32 *headers,
> +				     u32 data)
> +{
> +	struct tlp_rp_regpair_t tlp_rp_regdata;
> +
> +	tlp_rp_regdata.reg0 = headers[0];
> +	tlp_rp_regdata.reg1 = headers[1];
> +	tlp_rp_regdata.ctrl = RP_TX_SOP;
> +	tlp_write_tx(pcie, &tlp_rp_regdata);
> +
> +	tlp_rp_regdata.reg0 = headers[2];
> +	tlp_rp_regdata.reg1 = 0;
> +	tlp_rp_regdata.ctrl = 0;
> +	tlp_write_tx(pcie, &tlp_rp_regdata);
> +
> +	tlp_rp_regdata.reg0 = data;
> +	tlp_rp_regdata.reg1 = 0;
> +	tlp_rp_regdata.ctrl = RP_TX_EOP;
> +	tlp_write_tx(pcie, &tlp_rp_regdata);
> +}
> +
> +static int tlp_cfg_dword_read(struct altera_pcie *pcie, u8 bus, u32 devfn,
> +			      int where, u32 *value)
> +{
> +	int ret;
> +	u32 headers[TLP_HDR_SIZE];
> +
> +	if (bus == pcie->root_bus_nr)
> +		headers[0] = TLP_CFG_DW0(TLP_FMTTYPE_CFGRD0);
> +	else
> +		headers[0] = TLP_CFG_DW0(TLP_FMTTYPE_CFGRD1);
> +
> +	headers[1] = TLP_CFG_DW1(TLP_REQ_ID(pcie->root_bus_nr, devfn),
> +					TLP_READ_TAG);
> +	headers[2] = TLP_CFG_DW2(bus, devfn, where);
> +
> +	tlp_write_packet_unaligned(pcie, headers, 0);
> +
> +	ret = tlp_read_packet(pcie, value);
> +	if (ret != PCIBIOS_SUCCESSFUL)
> +		*value = ~0UL;	/* return 0xFFFFFFFF if error */
> +
> +	return ret;
> +}
> +
> +static int tlp_cfg_dword_write(struct altera_pcie *pcie, u8 bus, u32 devfn,
> +			       int where, u32 value)
> +{
> +	u32 headers[TLP_HDR_SIZE];
> +	int ret;
> +
> +	if (bus == pcie->root_bus_nr)
> +		headers[0] = TLP_CFG_DW0(TLP_FMTTYPE_CFGWR0);
> +	else
> +		headers[0] = TLP_CFG_DW0(TLP_FMTTYPE_CFGWR1);
> +
> +	headers[1] = TLP_CFG_DW1(TLP_REQ_ID(pcie->root_bus_nr, devfn),
> +					TLP_WRITE_TAG);
> +	headers[2] = TLP_CFG_DW2(bus, devfn, where);
> +
> +	/* check alignment to Qword */
> +	if ((where & 0x7) == 0)
> +		tlp_write_packet_aligned(pcie, headers, value);
> +	else
> +		tlp_write_packet_unaligned(pcie, headers, value);
> +
> +	ret = tlp_read_packet(pcie, NULL);
> +	if (ret != PCIBIOS_SUCCESSFUL)
> +		return ret;
> +
> +	/* Keep an eye out for changes to the root bus number */
> +	if ((bus == pcie->root_bus_nr) && (where == PCI_PRIMARY_BUS))
> +		pcie->root_bus_nr = (u8)(value);
> +
> +	return PCIBIOS_SUCCESSFUL;
> +}
> +
> +static int altera_pcie_cfg_read(struct pci_bus *bus, unsigned int devfn,
> +				int where, int size, u32 *value)
> +{
> +	struct altera_pcie *pcie = bus->sysdata;
> +	int ret;
> +
> +	if (!altera_pcie_valid_config(pcie, bus, PCI_SLOT(devfn))) {
> +		*value = ~0UL;
> +		return PCIBIOS_DEVICE_NOT_FOUND;
> +	}
> +
> +	ret = tlp_cfg_dword_read(pcie, bus->number, devfn,
> +				 (where & ~DWORD_MASK), value);
> +	if (ret != PCIBIOS_SUCCESSFUL)
> +		return ret;
> +
> +	if (size == 1)
> +		*value = (*value >> (8 * (where & 0x3))) & 0xff;
> +	else if (size == 2)
> +		*value = (*value >> (8 * (where & 0x2))) & 0xffff;

Please write this as a switch/case statement, with a default handling case.

> +
> +	return PCIBIOS_SUCCESSFUL;
> +}
> +
> +static int altera_pcie_cfg_write(struct pci_bus *bus, unsigned int devfn,
> +				 int where, int size, u32 value)
> +{
> +	struct altera_pcie *pcie = bus->sysdata;
> +	u32 data32 = value;
> +	u32 shift = 8 * (where & 3);
> +	int ret;
> +
> +	if (!altera_pcie_valid_config(pcie, bus, PCI_SLOT(devfn)))
> +		return PCIBIOS_DEVICE_NOT_FOUND;
> +
> +	/* write partial */
> +	if (size != sizeof(u32)) {
> +		ret = tlp_cfg_dword_read(pcie, bus->number, devfn,
> +					 where & ~DWORD_MASK, &data32);
> +		if (ret)
> +			return ret;
> +
> +		if (size == 2)
> +			data32 = (data32 & ~(0xffff << shift)) |
> +					((value & 0xffff) << shift);
> +		 else if (size == 1)
> +			data32 = (data32 & ~(0xff << shift)) |
> +					((value & 0xff) << shift);

Same here.

> +	}
> +
> +	return tlp_cfg_dword_write(pcie, bus->number, devfn,
> +		(where & ~DWORD_MASK), data32);
> +}
> +
> +static struct pci_ops altera_pcie_ops = {
> +	.read = altera_pcie_cfg_read,
> +	.write = altera_pcie_cfg_write,
> +};
> +
> +static int altera_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
> +				irq_hw_number_t hwirq)
> +{
> +	irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
> +	irq_set_chip_data(irq, domain->host_data);
> +	set_irq_flags(irq, IRQF_VALID);
> +
> +	return 0;
> +}
> +
> +static const struct irq_domain_ops intx_domain_ops = {
> +	.map = altera_pcie_intx_map,
> +};
> +
> +static void altera_pcie_isr(unsigned int irq, struct irq_desc *desc)
> +{
> +	struct irq_chip *chip = irq_desc_get_chip(desc);
> +	struct altera_pcie *pcie;
> +	unsigned long status;
> +	u32 bit;
> +	u32 virq;
> +
> +	chained_irq_enter(chip, desc);
> +	pcie = irq_desc_get_handler_data(desc);
> +
> +	do {
> +		status = cra_readl(pcie, P2A_INT_STATUS) & P2A_INT_STS_ALL;
> +		if (!status)
> +			break;
> +
> +		do {
> +			bit = find_first_bit(&status, INTX_NUM);
> +			/* clear interrupts */
> +			cra_writel(pcie, 1 << bit, P2A_INT_STATUS);
> +
> +			virq = irq_find_mapping(pcie->irq_domain, bit + 1);
> +			if (virq)
> +				generic_handle_irq(virq);
> +			else
> +				dev_info(&pcie->pdev->dev, "unexpected IRQ\n");
> +
> +			/* Clear the bit from status and repeat without reading
> +			 * again status register. */
> +			__clear_bit(bit, &status);
> +		} while (status);
> +	} while (1);

Please rewrite similarily to the way I proposed in your MSI driver.

> +
> +	chained_irq_exit(chip, desc);
> +}
> +
> +static void altera_pcie_release_of_pci_ranges(struct altera_pcie *pcie)
> +{
> +	pci_free_resource_list(&pcie->resources);
> +}
> +
> +static int altera_pcie_parse_request_of_pci_ranges(struct altera_pcie *pcie)
> +{
> +	int err, res_valid = 0;
> +	struct device *dev = &pcie->pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	resource_size_t iobase;
> +	struct resource_entry *win;
> +
> +	err = of_pci_get_host_bridge_resources(np, 0, 0xff, &pcie->resources,
> +					       &iobase);
> +	if (err)
> +		return err;
> +
> +	resource_list_for_each_entry(win, &pcie->resources) {
> +		struct resource *parent, *res = win->res;
> +
> +		switch (resource_type(res)) {
> +		case IORESOURCE_MEM:
> +			parent = &iomem_resource;
> +			res_valid |= !(res->flags & IORESOURCE_PREFETCH);
> +			break;
> +		default:
> +			continue;
> +		}
> +
> +		err = devm_request_resource(dev, parent, res);
> +		if (err)
> +			goto out_release_res;
> +	}
> +
> +	if (!res_valid) {
> +		dev_err(dev, "non-prefetchable memory resource required\n");
> +		err = -EINVAL;
> +		goto out_release_res;
> +	}
> +
> +	return 0;
> +
> +out_release_res:
> +	altera_pcie_release_of_pci_ranges(pcie);
> +	return err;
> +}
> +
> +static void altera_pcie_free_irq_domain(struct altera_pcie *pcie)
> +{
> +	int i;
> +	u32 irq;
> +
> +	for (i = 0; i < INTX_NUM; i++) {
> +		irq = irq_find_mapping(pcie->irq_domain, i);
> +		if (irq > 0)
> +			irq_dispose_mapping(irq);
> +	}
> +
> +	irq_domain_remove(pcie->irq_domain);
> +}
> +
> +static int altera_pcie_init_irq_domain(struct altera_pcie *pcie)
> +{
> +	struct device *dev = &pcie->pdev->dev;
> +	struct device_node *node = dev->of_node;
> +
> +	/* Setup INTx */
> +	pcie->irq_domain = irq_domain_add_linear(node, INTX_NUM,
> +					&intx_domain_ops, pcie);
> +	if (!pcie->irq_domain) {
> +		dev_err(dev, "Failed to get a INTx IRQ domain\n");
> +		return -ENOMEM;
> +	}
> +
> +	return 0;
> +}
> +
> +static int altera_pcie_parse_dt(struct altera_pcie *pcie)
> +{
> +	struct resource *cra;
> +	struct platform_device *pdev = pcie->pdev;
> +
> +	cra = platform_get_resource_byname(pdev, IORESOURCE_MEM, "Cra");
> +	if (!cra) {
> +		cra = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cra");
> +		if (!cra) {
> +			dev_err(&pdev->dev,
> +				"no cra memory resource defined\n");
> +			return -ENODEV;
> +		}
> +	}
> +
> +	pcie->cra_base = devm_ioremap_resource(&pdev->dev, cra);
> +	if (IS_ERR(pcie->cra_base)) {
> +		dev_err(&pdev->dev, "failed to map cra memory\n");
> +		return PTR_ERR(pcie->cra_base);
> +	}
> +
> +	/* setup IRQ */
> +	pcie->irq = platform_get_irq(pdev, 0);
> +	if (pcie->irq <= 0) {
> +		dev_err(&pdev->dev, "failed to get IRQ: %d\n", pcie->irq);
> +		return -EINVAL;
> +	}
> +
> +	irq_set_chained_handler_and_data(pcie->irq, altera_pcie_isr, pcie);
> +
> +	return 0;
> +}
> +
> +static int altera_pcie_probe(struct platform_device *pdev)
> +{
> +	struct altera_pcie *pcie;
> +	struct pci_bus *bus;
> +	int ret;
> +
> +	pcie = devm_kzalloc(&pdev->dev, sizeof(*pcie), GFP_KERNEL);
> +	if (!pcie)
> +		return -ENOMEM;
> +
> +	pcie->pdev = pdev;
> +
> +	ret = altera_pcie_parse_dt(pcie);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Parsing DT failed\n");
> +		return ret;
> +	}
> +
> +	INIT_LIST_HEAD(&pcie->resources);
> +
> +	ret = altera_pcie_parse_request_of_pci_ranges(pcie);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed add resources\n");
> +		return ret;
> +	}
> +
> +	ret = altera_pcie_init_irq_domain(pcie);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed creating IRQ Domain\n");
> +		return ret;
> +	}
> +
> +	pcie->root_bus_nr = 0;
> +
> +	/* clear all interrupts */
> +	cra_writel(pcie, P2A_INT_STS_ALL, P2A_INT_STATUS);
> +	/* enable all interrupts */
> +	cra_writel(pcie, P2A_INT_ENA_ALL, P2A_INT_ENABLE);
> +
> +	bus = pci_scan_root_bus(&pdev->dev, pcie->root_bus_nr, &altera_pcie_ops,
> +				pcie, &pcie->resources);
> +	if (!bus)
> +		return -ENOMEM;
> +
> +	pci_fixup_irqs(pci_common_swizzle, of_irq_parse_and_map_pci);
> +	pci_assign_unassigned_bus_resources(bus);
> +	pci_bus_add_devices(bus);
> +
> +	platform_set_drvdata(pdev, pcie);
> +	return ret;
> +}
> +
> +static int __exit altera_pcie_remove(struct platform_device *pdev)
> +{
> +	struct altera_pcie *pcie = platform_get_drvdata(pdev);
> +
> +	altera_pcie_free_irq_domain(pcie);
> +	platform_set_drvdata(pdev, NULL);
> +	return 0;
> +}
> +
> +static const struct of_device_id altera_pcie_of_match[] = {
> +	{ .compatible = "altr,pcie-root-port-1.0", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, altera_pcie_of_match);
> +
> +static struct platform_driver altera_pcie_driver = {
> +	.probe		= altera_pcie_probe,
> +	.remove		= altera_pcie_remove,
> +	.driver = {
> +		.name	= "altera-pcie",
> +		.of_match_table = altera_pcie_of_match,
> +	},
> +};
> +
> +module_platform_driver(altera_pcie_driver);
> +
> +MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>");
> +MODULE_DESCRIPTION("Altera PCIe host controller driver");
> +MODULE_LICENSE("GPL v2");
> 

Thanks,

	M.

On Tue, Aug 25, 2015 at 7:39 PM, Marc Zyngier <marc.zyngier@arm.com> wrote:
>

> > +
> > +static void altera_pcie_retrain(struct pci_dev *dev)
> > +{
> > +     u16 linkcap, linkstat;
> > +
> > +     /*
> > +      * Set the retrain bit if the PCIe rootport support > 2.5GB/s, but
> > +      * current speed is 2.5 GB/s.
> > +      */
> > +     pcie_capability_read_word(dev, PCI_EXP_LNKCAP, &linkcap);
> > +
> > +     if ((linkcap & PCI_EXP_LNKCAP_SLS) <= PCI_EXP_LNKCAP_SLS_2_5GB)
> > +             return;
> > +
> > +     pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &linkstat);
> > +     if ((linkstat & PCI_EXP_LNKSTA_CLS) == PCI_EXP_LNKSTA_CLS_2_5GB)
> > +             pcie_capability_set_word(dev, PCI_EXP_LNKCTL,
> > +                                      PCI_EXP_LNKCTL_RL);
> > +}
> > +DECLARE_PCI_FIXUP_EARLY(PCI_ANY_ID, PCI_ANY_ID, altera_pcie_retrain);
>
> Do I read this correctly? This function is being called on any PCI
> device, without any filtering? What if the platform is not using this
> driver despite the driver being compiled in?
Will change it to Altera vendor ID.

>
> > +
> > +static void altera_pcie_fixup_res(struct pci_dev *dev)
> > +{
> > +     /*
> > +      * Prevent enumeration of root port.
> > +      */
> > +     if (!dev->bus->parent && dev->devfn == 0) {
> > +             int i;
> > +
> > +             for (i = 0; i < PCI_NUM_RESOURCES; i++) {
> > +                     dev->resource[i].start = 0;
> > +                     dev->resource[i].end   = 0;
> > +                     dev->resource[i].flags   = 0;
> > +             }
> > +     }
> > +}
> > +DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, altera_pcie_fixup_res);
>
> Same here. I also question the validity of nuking the resources, but I'm
> not a PCI expert.
We want to hide the host BARs from kernel as their content doesn't fix
well in the resource management and cause the pci enumeration failed.
Some other controllers also using same way to hide the host BARs resources.
>
> > +
> > +static inline void cra_writel(struct altera_pcie *pcie, u32 value, u32 reg)
> > +{
> > +     writel_relaxed(value, pcie->cra_base + reg);
> > +}
> > +
> > +static inline u32 cra_readl(struct altera_pcie *pcie, u32 reg)
> > +{
> > +     return readl_relaxed(pcie->cra_base + reg);
> > +}
> > +
> > +static void tlp_read_rx(struct altera_pcie *pcie,
> > +                     struct tlp_rp_regpair_t *tlp_rp_regdata)
> > +{
> > +     tlp_rp_regdata->ctrl = cra_readl(pcie, RP_RXCPL_STATUS);
> > +     tlp_rp_regdata->reg0 = cra_readl(pcie, RP_RXCPL_REG0);
> > +     tlp_rp_regdata->reg1 = cra_readl(pcie, RP_RXCPL_REG1);
> > +}
> > +
> > +static void tlp_write_tx(struct altera_pcie *pcie,
> > +                      struct tlp_rp_regpair_t *tlp_rp_regdata)
> > +{
> > +     cra_writel(pcie, tlp_rp_regdata->reg0, RP_TX_REG0);
> > +     cra_writel(pcie, tlp_rp_regdata->reg1, RP_TX_REG1);
> > +     cra_writel(pcie, tlp_rp_regdata->ctrl, RP_TX_CNTRL);
> > +}
> > +
> > +static bool altera_pcie_link_is_up(struct altera_pcie *pcie)
> > +{
> > +     return !!(cra_readl(pcie, RP_LTSSM) & LTSSM_L0);
> > +}
> > +
> > +static bool altera_pcie_valid_config(struct altera_pcie *pcie,
> > +                                  struct pci_bus *bus, int dev)
> > +{
> > +     /* If there is no link, then there is no device */
> > +     if (bus->number != pcie->root_bus_nr) {
> > +             if (!altera_pcie_link_is_up(pcie))
> > +                     return false;
> > +     }
> > +
> > +     /* access only one slot on each root port */
> > +     if (bus->number == pcie->root_bus_nr && dev > 0)
> > +             return false;
> > +
> > +     /*
> > +      * Do not read more than one device on the bus directly attached
> > +      * to RC.
> > +      */
> > +     if (bus->primary == pcie->root_bus_nr && dev > 0)
> > +             return false;
> > +
> > +      return true;
> > +}
> > +
> > +static int tlp_read_packet(struct altera_pcie *pcie, u32 *value)
> > +{
> > +     u8 loop;
> > +     struct tlp_rp_regpair_t tlp_rp_regdata;
> > +
> > +     for (loop = 0; loop < TLP_LOOP; loop++) {
> > +             tlp_read_rx(pcie, &tlp_rp_regdata);
> > +             if (tlp_rp_regdata.ctrl & RP_RXCPL_EOP) {
> > +                     if (value)
> > +                             *value = tlp_rp_regdata.reg0;
> > +                     return PCIBIOS_SUCCESSFUL;
> > +             }
> > +             udelay(5);
> > +     }
> > +
> > +     return -ENOENT;
> > +}
> > +
> > +static void tlp_write_packet_unaligned(struct altera_pcie *pcie, u32 *headers,
> > +                                    u32 data)
> > +{
> > +     struct tlp_rp_regpair_t tlp_rp_regdata;
> > +
> > +     tlp_rp_regdata.reg0 = headers[0];
> > +     tlp_rp_regdata.reg1 = headers[1];
> > +     tlp_rp_regdata.ctrl = RP_TX_SOP;
> > +     tlp_write_tx(pcie, &tlp_rp_regdata);
> > +
> > +     tlp_rp_regdata.reg0 = headers[2];
> > +     tlp_rp_regdata.reg1 = data;
> > +     tlp_rp_regdata.ctrl = RP_TX_EOP;
> > +     tlp_write_tx(pcie, &tlp_rp_regdata);
> > +}
> > +
> > +static void tlp_write_packet_aligned(struct altera_pcie *pcie, u32 *headers,
> > +                                  u32 data)
> > +{
> > +     struct tlp_rp_regpair_t tlp_rp_regdata;
> > +
> > +     tlp_rp_regdata.reg0 = headers[0];
> > +     tlp_rp_regdata.reg1 = headers[1];
> > +     tlp_rp_regdata.ctrl = RP_TX_SOP;
> > +     tlp_write_tx(pcie, &tlp_rp_regdata);
> > +
> > +     tlp_rp_regdata.reg0 = headers[2];
> > +     tlp_rp_regdata.reg1 = 0;
> > +     tlp_rp_regdata.ctrl = 0;
> > +     tlp_write_tx(pcie, &tlp_rp_regdata);
> > +
> > +     tlp_rp_regdata.reg0 = data;
> > +     tlp_rp_regdata.reg1 = 0;
> > +     tlp_rp_regdata.ctrl = RP_TX_EOP;
> > +     tlp_write_tx(pcie, &tlp_rp_regdata);
> > +}
> > +
> > +static int tlp_cfg_dword_read(struct altera_pcie *pcie, u8 bus, u32 devfn,
> > +                           int where, u32 *value)
> > +{
> > +     int ret;
> > +     u32 headers[TLP_HDR_SIZE];
> > +
> > +     if (bus == pcie->root_bus_nr)
> > +             headers[0] = TLP_CFG_DW0(TLP_FMTTYPE_CFGRD0);
> > +     else
> > +             headers[0] = TLP_CFG_DW0(TLP_FMTTYPE_CFGRD1);
> > +
> > +     headers[1] = TLP_CFG_DW1(TLP_REQ_ID(pcie->root_bus_nr, devfn),
> > +                                     TLP_READ_TAG);
> > +     headers[2] = TLP_CFG_DW2(bus, devfn, where);
> > +
> > +     tlp_write_packet_unaligned(pcie, headers, 0);
> > +
> > +     ret = tlp_read_packet(pcie, value);
> > +     if (ret != PCIBIOS_SUCCESSFUL)
> > +             *value = ~0UL;  /* return 0xFFFFFFFF if error */
> > +
> > +     return ret;
> > +}
> > +
> > +static int tlp_cfg_dword_write(struct altera_pcie *pcie, u8 bus, u32 devfn,
> > +                            int where, u32 value)
> > +{
> > +     u32 headers[TLP_HDR_SIZE];
> > +     int ret;
> > +
> > +     if (bus == pcie->root_bus_nr)
> > +             headers[0] = TLP_CFG_DW0(TLP_FMTTYPE_CFGWR0);
> > +     else
> > +             headers[0] = TLP_CFG_DW0(TLP_FMTTYPE_CFGWR1);
> > +
> > +     headers[1] = TLP_CFG_DW1(TLP_REQ_ID(pcie->root_bus_nr, devfn),
> > +                                     TLP_WRITE_TAG);
> > +     headers[2] = TLP_CFG_DW2(bus, devfn, where);
> > +
> > +     /* check alignment to Qword */
> > +     if ((where & 0x7) == 0)
> > +             tlp_write_packet_aligned(pcie, headers, value);
> > +     else
> > +             tlp_write_packet_unaligned(pcie, headers, value);
> > +
> > +     ret = tlp_read_packet(pcie, NULL);
> > +     if (ret != PCIBIOS_SUCCESSFUL)
> > +             return ret;
> > +
> > +     /* Keep an eye out for changes to the root bus number */
> > +     if ((bus == pcie->root_bus_nr) && (where == PCI_PRIMARY_BUS))
> > +             pcie->root_bus_nr = (u8)(value);
> > +
> > +     return PCIBIOS_SUCCESSFUL;
> > +}
> > +
> > +static int altera_pcie_cfg_read(struct pci_bus *bus, unsigned int devfn,
> > +                             int where, int size, u32 *value)
> > +{
> > +     struct altera_pcie *pcie = bus->sysdata;
> > +     int ret;
> > +
> > +     if (!altera_pcie_valid_config(pcie, bus, PCI_SLOT(devfn))) {
> > +             *value = ~0UL;
> > +             return PCIBIOS_DEVICE_NOT_FOUND;
> > +     }
> > +
> > +     ret = tlp_cfg_dword_read(pcie, bus->number, devfn,
> > +                              (where & ~DWORD_MASK), value);
> > +     if (ret != PCIBIOS_SUCCESSFUL)
> > +             return ret;
> > +
> > +     if (size == 1)
> > +             *value = (*value >> (8 * (where & 0x3))) & 0xff;
> > +     else if (size == 2)
> > +             *value = (*value >> (8 * (where & 0x2))) & 0xffff;
>
> Please write this as a switch/case statement, with a default handling case.
Okay.

>
> > +
> > +     return PCIBIOS_SUCCESSFUL;
> > +}
> > +
> > +static int altera_pcie_cfg_write(struct pci_bus *bus, unsigned int devfn,
> > +                              int where, int size, u32 value)
> > +{
> > +     struct altera_pcie *pcie = bus->sysdata;
> > +     u32 data32 = value;
> > +     u32 shift = 8 * (where & 3);
> > +     int ret;
> > +
> > +     if (!altera_pcie_valid_config(pcie, bus, PCI_SLOT(devfn)))
> > +             return PCIBIOS_DEVICE_NOT_FOUND;
> > +
> > +     /* write partial */
> > +     if (size != sizeof(u32)) {
> > +             ret = tlp_cfg_dword_read(pcie, bus->number, devfn,
> > +                                      where & ~DWORD_MASK, &data32);
> > +             if (ret)
> > +                     return ret;
> > +
> > +             if (size == 2)
> > +                     data32 = (data32 & ~(0xffff << shift)) |
> > +                                     ((value & 0xffff) << shift);
> > +              else if (size == 1)
> > +                     data32 = (data32 & ~(0xff << shift)) |
> > +                                     ((value & 0xff) << shift);
>
> Same here.
Okay.

> > +     }
> > +
> > +     return tlp_cfg_dword_write(pcie, bus->number, devfn,
> > +             (where & ~DWORD_MASK), data32);
> > +}
> > +
> > +static struct pci_ops altera_pcie_ops = {
> > +     .read = altera_pcie_cfg_read,
> > +     .write = altera_pcie_cfg_write,
> > +};
> > +
> > +static int altera_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
> > +                             irq_hw_number_t hwirq)
> > +{
> > +     irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
> > +     irq_set_chip_data(irq, domain->host_data);
> > +     set_irq_flags(irq, IRQF_VALID);
> > +
> > +     return 0;
> > +}
> > +
> > +static const struct irq_domain_ops intx_domain_ops = {
> > +     .map = altera_pcie_intx_map,
> > +};
> > +
> > +static void altera_pcie_isr(unsigned int irq, struct irq_desc *desc)
> > +{
> > +     struct irq_chip *chip = irq_desc_get_chip(desc);
> > +     struct altera_pcie *pcie;
> > +     unsigned long status;
> > +     u32 bit;
> > +     u32 virq;
> > +
> > +     chained_irq_enter(chip, desc);
> > +     pcie = irq_desc_get_handler_data(desc);
> > +
> > +     do {
> > +             status = cra_readl(pcie, P2A_INT_STATUS) & P2A_INT_STS_ALL;
> > +             if (!status)
> > +                     break;
> > +
> > +             do {
> > +                     bit = find_first_bit(&status, INTX_NUM);
> > +                     /* clear interrupts */
> > +                     cra_writel(pcie, 1 << bit, P2A_INT_STATUS);
> > +
> > +                     virq = irq_find_mapping(pcie->irq_domain, bit + 1);
> > +                     if (virq)
> > +                             generic_handle_irq(virq);
> > +                     else
> > +                             dev_info(&pcie->pdev->dev, "unexpected IRQ\n");
> > +
> > +                     /* Clear the bit from status and repeat without reading
> > +                      * again status register. */
> > +                     __clear_bit(bit, &status);
> > +             } while (status);
> > +     } while (1);
>
> Please rewrite similarily to the way I proposed in your MSI driver.
Okay.

Thanks.

Regards
Ley Foon
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