Subject: [PATCH v3] pcie: Add Xilinx PCIe Host Bridge IP driver

From: [email-masked] (Bjorn Helgaas)
Date: Wed, 30 Apr 2014 15:41:09 -0600

On Tue, Apr 15, 2014 at 05:08:31PM +0530, Srikanth Thokala wrote:
> This is the driver for Xilinx AXI PCIe Host Bridge Soft IP
> 
> Signed-off-by: Srikanth Thokala <[email-masked]>
> ---
> Changes in v3:
> - Rebased on v3.15.0-rc1
> - Added support for interrupt-map DT functionality.
> - Removed map_irq() wrapper, instead using of_irq_parse_and_map_pci().
> - Modified resource mapping logic as per the series
>   "PCI: ARM: add support for generic PCI host controller"
> - Modified devicetree binding documentation to update with interrupt-
>   map properties.
> - Use devm calls wherever applicable.
> - Fixed minor comments from Jason
> - Thanks Jason for the review and suggestions.
> 
> Changes in v2:
> - Rebased on v3.14.0-rc8
> - Removed IP specific DT properties like include-rc, axibar-num etc.,
>   as suggested by Jason and Bjorn, Thanks
> ---
>  .../devicetree/bindings/pci/xilinx-pcie.txt        |   62 ++
>  drivers/pci/host/Kconfig                           |    7 +
>  drivers/pci/host/Makefile                          |    1 +
>  drivers/pci/host/pci-xilinx.c                      |  999 ++++++++++++++++++++
>  4 files changed, 1069 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pci/xilinx-pcie.txt
>  create mode 100644 drivers/pci/host/pci-xilinx.c
> 
> diff --git a/Documentation/devicetree/bindings/pci/xilinx-pcie.txt b/Documentation/devicetree/bindings/pci/xilinx-pcie.txt
> new file mode 100644
> index 0000000..2fb28e0
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pci/xilinx-pcie.txt
> @@ -0,0 +1,62 @@
> +* Xilinx AXI PCIe Root Port Bridge DT description
> +
> +Required properties:
> +- #address-cells: Address representation for root ports, set to <3>
> +- #size-cells: Size representation for root ports, set to <2>
> +- #interrupt-cells: specifies the number of cells needed to encode an
> +	interrupt source. The value must be 1.
> +- compatible: Should contain "xlnx,axi-pcie-host-1.00.a"
> +- reg: Should contain AXI PCIe registers location and length
> +- device_type: must be "pci"
> +- interrupts: Should contain AXI PCIe interrupt
> +- interrupt-map-mask,
> +  interrupt-map: standard PCI properties to define the mapping of the
> +	PCI interface to interrupt numbers.
> +- ranges: ranges for the PCI memory regions (I/O space region is noti
> +	supported by hardware)
> +	Please refer to the standard PCI bus binding document for a more
> +	detailed explanation
> +
> +Optional properties:
> +- bus-range: PCI bus numbers covered
> +
> +Interrupt controller child node
> ++++++++++++++++++++++++++++++++
> +Required properties:
> +- interrupt-controller: identifies the node as an interrupt controller
> +- #address-cells: specifies the number of cells needed to encode an
> +	address. The value must be 0.
> +- #interrupt-cells: specifies the number of cells needed to encode an
> +	interrupt source. The value must be 1.
> +
> +NOTE:
> +The core provides a single interrupt for both INTx/MSI messages. So,
> +created a interrupt controller node to support 'interrupt-map' DT
> +functionality.  The driver will create an IRQ domain for this map, decode
> +the four INTx interrupts in ISR and route them to this domain.
> +
> +
> +Example:
> +++++++++
> +
> +	pci_express: axi-pcie at 50000000 {
> +		#address-cells = <3>;
> +		#size-cells = <2>;
> +		#interrupt-cells = <1>;
> +		compatible = "xlnx,axi-pcie-host-1.00.a";
> +		reg = < 0x50000000 0x10000000 >;
> +		device_type = "pci";
> +		interrupts = < 0 52 4 >;
> +		interrupt-map-mask = <0 0 0 7>;
> +		interrupt-map = <0 0 0 1 &pcie_intc 1>,
> +				<0 0 0 2 &pcie_intc 2>,
> +				<0 0 0 3 &pcie_intc 3>,
> +				<0 0 0 4 &pcie_intc 4>;
> +		ranges = < 0x02000000 0 0x60000000 0x60000000 0 0x10000000 >;
> +
> +		pcie_intc: interrupt-controller {
> +			interrupt-controller;
> +			#address-cells = <0>;
> +			#interrupt-cells = <1>;
> +		}
> +	};
> diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
> index a6f67ec..71afdcd 100644
> --- a/drivers/pci/host/Kconfig
> +++ b/drivers/pci/host/Kconfig
> @@ -33,4 +33,11 @@ config PCI_RCAR_GEN2
>  	  There are 3 internal PCI controllers available with a single
>  	  built-in EHCI/OHCI host controller present on each one.
>  
> +config PCI_XILINX
> +	bool "Xilinx AXI PCIe host bridge support"
> +	depends on ARCH_ZYNQ
> +	help
> +	  Say 'Y' here if you want kernel to support the Xilinx AXI PCIe
> +	  Host Bridge driver.
> +
>  endmenu
> diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
> index 13fb333..4e9c843 100644
> --- a/drivers/pci/host/Makefile
> +++ b/drivers/pci/host/Makefile
> @@ -4,3 +4,4 @@ obj-$(CONFIG_PCI_IMX6) += pci-imx6.o
>  obj-$(CONFIG_PCI_MVEBU) += pci-mvebu.o
>  obj-$(CONFIG_PCI_TEGRA) += pci-tegra.o
>  obj-$(CONFIG_PCI_RCAR_GEN2) += pci-rcar-gen2.o
> +obj-$(CONFIG_PCI_XILINX) += pci-xilinx.o
> diff --git a/drivers/pci/host/pci-xilinx.c b/drivers/pci/host/pci-xilinx.c
> new file mode 100644
> index 0000000..d9afe66
> --- /dev/null
> +++ b/drivers/pci/host/pci-xilinx.c
> @@ -0,0 +1,999 @@
> +/*
> + * PCIe host controller driver for Xilinx AXI PCIe Bridge
> + *
> + * Copyright (c) 2012 - 2014 Xilinx, Inc.
> + *
> + * Based on the Tegra PCIe driver
> + *
> + * Bits taken from Synopsys Designware Host controller driver and
> + * ARM PCI Host generic driver.
> + *
> + * This program is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation, either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/irqdomain.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/msi.h>
> +#include <linux/of_address.h>
> +#include <linux/of_pci.h>
> +#include <linux/of_platform.h>
> +#include <linux/of_irq.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +
> +/* Register definitions */
> +#define XILINX_PCIE_REG_VSECC		0x00000128
> +#define XILINX_PCIE_REG_VSECH		0x0000012c
> +#define XILINX_PCIE_REG_BIR		0x00000130
> +#define XILINX_PCIE_REG_BSCR		0x00000134
> +#define XILINX_PCIE_REG_IDR		0x00000138
> +#define XILINX_PCIE_REG_IMR		0x0000013c
> +#define XILINX_PCIE_REG_BLR		0x00000140
> +#define XILINX_PCIE_REG_PSCR		0x00000144
> +#define XILINX_PCIE_REG_RPSC		0x00000148
> +#define XILINX_PCIE_REG_MSIBASE1	0x0000014c
> +#define XILINX_PCIE_REG_MSIBASE2	0x00000150
> +#define XILINX_PCIE_REG_RPEFR		0x00000154
> +#define XILINX_PCIE_REG_RPIFR1		0x00000158
> +#define XILINX_PCIE_REG_RPIFR2		0x0000015c
> +#define XILINX_PCIE_REG_VSECC2		0x00000200
> +#define XILINX_PCIE_REG_VSECH2		0x00000204
> +
> +/* Interrupt registers definitions */
> +#define XILINX_PCIE_INTR_LINK_DOWN	BIT(0)
> +#define XILINX_PCIE_INTR_ECRC_ERR	BIT(1)
> +#define XILINX_PCIE_INTR_STR_ERR	BIT(2)
> +#define XILINX_PCIE_INTR_HOT_RESET	BIT(3)
> +#define XILINX_PCIE_INTR_CFG_COMPL	GENMASK(7, 5)
> +#define XILINX_PCIE_INTR_CFG_TIMEOUT	BIT(8)
> +#define XILINX_PCIE_INTR_CORRECTABLE	BIT(9)
> +#define XILINX_PCIE_INTR_NONFATAL	BIT(10)
> +#define XILINX_PCIE_INTR_FATAL		BIT(11)
> +#define XILINX_PCIE_INTR_INTX		BIT(16)
> +#define XILINX_PCIE_INTR_MSI		BIT(17)
> +#define XILINX_PCIE_INTR_SLV_UNSUPP	BIT(20)
> +#define XILINX_PCIE_INTR_SLV_UNEXP	BIT(21)
> +#define XILINX_PCIE_INTR_SLV_COMPL	BIT(22)
> +#define XILINX_PCIE_INTR_SLV_ERRP	BIT(23)
> +#define XILINX_PCIE_INTR_SLV_CMPABT	BIT(24)
> +#define XILINX_PCIE_INTR_SLV_ILLBUR	BIT(25)
> +#define XILINX_PCIE_INTR_MST_DECERR	BIT(26)
> +#define XILINX_PCIE_INTR_MST_SLVERR	BIT(27)
> +#define XILINX_PCIE_INTR_MST_ERRP	BIT(28)
> +#define XILINX_PCIE_IMR_ALL_MASK	0x1FF30FED
> +#define XILINX_PCIE_IDR_ALL_MASK	0xFFFFFFFF
> +
> +/* Root Port Error FIFO Read Register definitions */
> +#define XILINX_PCIE_RPEFR_ERR_VALID	BIT(18)
> +#define XILINX_PCIE_RPEFR_REQ_ID	GENMASK(15, 0)
> +#define XILINX_PCIE_RPEFR_ALL_MASK	0xFFFFFFFF
> +
> +/* Root Port Interrupt FIFO Read Register 1 definitions */
> +#define XILINX_PCIE_RPIFR1_INTR_VALID	BIT(31)
> +#define XILINX_PCIE_RPIFR1_MSI_INTR	BIT(30)
> +#define XILINX_PCIE_RPIFR1_INTR_ASSRT	BIT(29)
> +#define XILINX_PCIE_RPIFR1_INTR_MASK	GENMASK(28, 27)
> +#define XILINX_PCIE_RPIFR1_MSI_ADR_MASK	GENMASK(26, 16)
> +#define XILINX_PCIE_RPIFR1_ALL_MASK	0xFFFFFFFF
> +#define XILINX_PCIE_RPIFR1_INTR_SHIFT		27
> +#define XILINX_PCIE_RPIFR1_MSI_ADR_SHIFT	16
> +
> +/* Bridge Info Register definitions */
> +#define XILINX_PCIE_BIR_ECAM_SZ_MASK	GENMASK(18, 16)
> +#define XILINX_PCIE_BIR_ECAM_SZ_SHIFT	16
> +
> +/* Root Port Interrupt FIFO Read Register 2 definitions */
> +#define XILINX_PCIE_RPIFR2_MSG_DATA	GENMASK(15, 0)
> +
> +/* Root Port Status/control Register definitions */
> +#define XILINX_PCIE_REG_RPSC_BEN	BIT(0)
> +
> +/* Phy Status/Control Register definitions */
> +#define XILINX_PCIE_REG_PSCR_LNKUP	BIT(11)
> +
> +/* ECAM definitions */
> +#define ECAM_BUS_NUM_SHIFT		20
> +#define ECAM_DEV_NUM_SHIFT		12
> +
> +/* PCI Configuration space Bus Number Register definitions */
> +#define PCI_SECONDARY_BUS_NUM_SHIFT	8
> +#define PCI_SUBORDINATE_BUS_NUM_SHIFT	16
> +#define PCI_LATENCY_TIMER_MASK		GENMASK(31, 24)
> +
> +/* Number of MSI IRQs */
> +#define XILINX_NUM_MSI_IRQS		128
> +
> +/* Number of Memory Resources */
> +#define XILINX_MAX_NUM_RESOURCES	3
> +
> +/**
> + * struct xilinx_pcie_port - PCIe port information
> + * @reg_base: IO Mapped Register Base
> + * @irq: Interrupt number
> + * @msg_addr: MSI message address
> + * @root_busno: Root Bus number
> + * @link_up: Link status flag
> + * @dev: Device pointer
> + * @irq_domain: IRQ domain pointer
> + */
> +struct xilinx_pcie_port {
> +	void __iomem *reg_base;
> +	u32 irq;
> +	unsigned long msg_addr;
> +	u8 root_busno;
> +	bool link_up;
> +	struct device *dev;
> +	struct irq_domain *irq_domain;
> +};
> +
> +static DECLARE_BITMAP(msi_irq_in_use, XILINX_NUM_MSI_IRQS);
> +
> +static inline struct xilinx_pcie_port *sys_to_pcie(struct pci_sys_data *sys)
> +{
> +	return sys->private_data;
> +}
> +
> +static inline u32 pcie_read(struct xilinx_pcie_port *port, u32 reg)
> +{
> +	return readl(port->reg_base + reg);
> +}
> +
> +static inline void pcie_write(struct xilinx_pcie_port *port,
> +			      u32 val, u32 reg)
> +{
> +	writel(val, port->reg_base + reg);
> +}
> +
> +static inline bool xilinx_pcie_is_link_up(struct xilinx_pcie_port *port)
> +{
> +	return (pcie_read(port, XILINX_PCIE_REG_PSCR) &
> +		XILINX_PCIE_REG_PSCR_LNKUP) ? 1 : 0;
> +}
> +
> +/**
> + * xilinx_pcie_clear_err_interrupts - Clear Error Interrupts
> + * @port: PCIe port information
> + */
> +static inline void
> +xilinx_pcie_clear_err_interrupts(struct xilinx_pcie_port *port)
> +{
> +	u32 val = pcie_read(port, XILINX_PCIE_REG_RPEFR);
> +
> +	if (val & XILINX_PCIE_RPEFR_ERR_VALID) {
> +		dev_dbg(port->dev, "Requester ID %d\n",
> +			val & XILINX_PCIE_RPEFR_REQ_ID);
> +		pcie_write(port, XILINX_PCIE_RPEFR_ALL_MASK,
> +			   XILINX_PCIE_REG_RPEFR);
> +	}
> +}
> +
> +/**
> + * xilinx_pcie_verify_config - Verify configuration
> + * @bus: Bus structure of current bus
> + * @devfn: device/function
> + *
> + * Return: 0 on success and PCIBIOS_DEVICE_NOT_FOUND on error

This comment about the return value doesn't match the code.

> + */
> +static int xilinx_pcie_verify_config(struct pci_bus *bus,
> +				     unsigned int devfn)
> +{
> +	struct xilinx_pcie_port *port = sys_to_pcie(bus->sysdata);
> +
> +	/* Check if link is up when trying to access downstream ports */
> +	if (bus->number != port->root_busno)
> +		if (!xilinx_pcie_is_link_up(port))
> +			return 0;
> +
> +	/* Only one device down on each root port */
> +	if (bus->number == port->root_busno && devfn > 0)
> +		return 0;
> +
> +	/*
> +	 * Do not read more than one device on the bus directly attached
> +	 * to RC.
> +	 */
> +	if (bus->primary == port->root_busno && devfn > 0)
> +		return 0;
> +
> +	return 1;
> +}
> +
> +/**
> + * xilinx_pcie_get_config_base - Get configuration base
> + * @bus: Bus structure of current bus

There's not really a concept of a "current" bus here.  I think these
function comments that repeat what the function and argument names already
tell us are of minimal value.  But I know some people do like them.

> + * @devfn: Device/function
> + * @where: Offset from base
> + *
> + * Return: Base address of the configuration space needed to be
> + *	   accessed.
> + */
> +static void __iomem *xilinx_pcie_get_config_base(struct pci_bus *bus,
> +						 unsigned int devfn,
> +						 int where)
> +{
> +	struct xilinx_pcie_port *port = sys_to_pcie(bus->sysdata);
> +	int relbus;
> +
> +	relbus = (bus->number << ECAM_BUS_NUM_SHIFT) |
> +		 (devfn << ECAM_DEV_NUM_SHIFT);
> +
> +	return port->reg_base + relbus + where;
> +}
> +
> +/**
> + * xilinx_pcie_read_config - Read configuration space
> + * @bus: Bus structure of current bus
> + * @devfn: Device/function
> + * @where: Offset from base
> + * @size: Byte/word/dword
> + * @val: Value to be read
> + *
> + * Return: PCIBIOS_SUCCESSFUL on success
> + *	   EINVAL/PCIBIOS_DEVICE_NOT_FOUND/PCIBIOS_BAD_REGISTER_NUMBER
> + *	   on failure.
> + */
> +static int xilinx_pcie_read_config(struct pci_bus *bus,
> +				   unsigned int devfn, int where,
> +				   int size, u32 *val)
> +{
> +	struct xilinx_pcie_port *port = sys_to_pcie(bus->sysdata);
> +	void __iomem *addr;
> +
> +	if (!port) {
> +		BUG();
> +		return -EINVAL;
> +	}
> +
> +	if (!xilinx_pcie_verify_config(bus, devfn)) {
> +		*val = 0xFFFFFFFF;
> +		return PCIBIOS_DEVICE_NOT_FOUND;
> +	}
> +
> +	addr = xilinx_pcie_get_config_base(bus, devfn, where);
> +
> +	switch (size) {
> +	case 1:
> +		*val = readb(addr);
> +		break;
> +	case 2:
> +		*val = readw(addr);
> +		break;
> +	default:
> +		*val = readl(addr);
> +		break;
> +	}
> +
> +	return PCIBIOS_SUCCESSFUL;
> +}
> +
> +/**
> + * xilinx_pcie_write_config - Write configuration space
> + * @bus: Bus structure of current bus
> + * @devfn: Device/function
> + * @where: Offset from base
> + * @size: Byte/word/dword
> + * @val: Value to be written to device
> + *
> + * Return: PCIBIOS_SUCCESSFUL on success,
> + *	   EINVAL/PCIBIOS_DEVICE_NOT_FOUND/PCIBIOS_BAD_REGISTER_NUMBER
> + *	   on failure.
> + */
> +static int xilinx_pcie_write_config(struct pci_bus *bus,
> +				    unsigned int devfn, int where,
> +				    int size, u32 val)
> +{
> +	struct xilinx_pcie_port *port = sys_to_pcie(bus->sysdata);
> +	void __iomem *addr;
> +
> +	if (!port) {
> +		BUG();
> +		return -EINVAL;
> +	}
> +
> +	if (!xilinx_pcie_verify_config(bus, devfn))
> +		return PCIBIOS_DEVICE_NOT_FOUND;
> +
> +	addr = xilinx_pcie_get_config_base(bus, devfn, where);
> +
> +	switch (size) {
> +	case 1:
> +		writeb(val, addr);
> +		break;
> +	case 2:
> +		writew(val, addr);
> +		break;
> +	default:
> +		writel(val, addr);
> +		break;
> +	}
> +
> +	return PCIBIOS_SUCCESSFUL;
> +}
> +
> +/* PCIe operations */
> +static struct pci_ops xilinx_pcie_ops = {
> +	.read  = xilinx_pcie_read_config,
> +	.write = xilinx_pcie_write_config,
> +};
> +
> +/* MSI functions */
> +
> +/**
> + * xilinx_pcie_destroy_msi - Free MSI number
> + * @irq: IRQ to be freed
> + */
> +static void xilinx_pcie_destroy_msi(unsigned int irq)
> +{
> +	struct irq_desc *desc;
> +	struct msi_desc *msi;
> +	struct xilinx_pcie_port *port;
> +
> +	desc = irq_to_desc(irq);
> +	msi = irq_desc_get_msi_desc(desc);
> +	port = sys_to_pcie(msi->dev->bus->sysdata);
> +	if (!port) {
> +		BUG();
> +		return;
> +	}
> +
> +	if (!test_bit(irq, msi_irq_in_use))
> +		dev_err(port->dev, "Trying to free unused MSI#%d\n", irq);
> +	else
> +		clear_bit(irq, msi_irq_in_use);
> +}
> +
> +/**
> + * xilinx_pcie_assign_msi - Allocate MSI number
> + * @port: PCIe port structure
> + *
> + * Return: A valid IRQ on success and error value on failure.
> + */
> +static int xilinx_pcie_assign_msi(struct xilinx_pcie_port *port)
> +{
> +	int pos;
> +
> +	pos = find_first_zero_bit(msi_irq_in_use, XILINX_NUM_MSI_IRQS);
> +	if (pos < XILINX_NUM_MSI_IRQS)
> +		set_bit(pos, msi_irq_in_use);
> +	else
> +		return -ENOSPC;
> +
> +	return irq_find_mapping(port->irq_domain, pos);
> +}
> +
> +/**
> + * xilinx_msi_teardown_irq - Destroy the MSI
> + * @chip: MSI Chip descriptor
> + * @irq: MSI IRQ to destroy
> + */
> +static void xilinx_msi_teardown_irq(struct msi_chip *chip, unsigned int irq)
> +{
> +	xilinx_pcie_destroy_msi(irq);
> +}
> +
> +/**
> + * xilinx_pcie_msi_setup_irq - Setup MSI request
> + * @chip: MSI chip pointer
> + * @pdev: PCIe device pointer
> + * @desc: MSI descriptor pointer
> + *
> + * Return: '0' on success and error value on failure
> + */
> +static int xilinx_pcie_msi_setup_irq(struct msi_chip *chip,
> +				     struct pci_dev *pdev,
> +				     struct msi_desc *desc)
> +{
> +	struct xilinx_pcie_port *port = sys_to_pcie(pdev->bus->sysdata);
> +	int irq;
> +	struct msi_msg msg;
> +
> +	if (!port) {
> +		BUG();
> +		return -EINVAL;
> +	}
> +
> +	irq = xilinx_pcie_assign_msi(port);
> +	if (irq < 0)
> +		return irq;
> +
> +	irq_set_msi_desc(irq, desc);
> +
> +	msg.address_hi = 0;
> +	msg.address_lo = virt_to_phys((void *)port->msg_addr);
> +	msg.data = irq;
> +
> +	write_msi_msg(irq, &msg);
> +
> +	return 0;
> +}
> +
> +/* MSI Chip Descriptor */
> +static struct msi_chip xilinx_pcie_msi_chip = {
> +	.setup_irq = xilinx_pcie_msi_setup_irq,
> +	.teardown_irq = xilinx_msi_teardown_irq,
> +};
> +
> +/* HW Interrupt Chip Descriptor */
> +static struct irq_chip xilinx_msi_irq_chip = {
> +	.name = "Xilinx PCIe MSI",
> +	.irq_enable = unmask_msi_irq,
> +	.irq_disable = mask_msi_irq,
> +	.irq_mask = mask_msi_irq,
> +	.irq_unmask = unmask_msi_irq,
> +};
> +
> +/**
> + * xilinx_pcie_msi_map - Set the handler for the MSI and mark IRQ as valid
> + * @domain: IRQ domain
> + * @irq: Virtual IRQ number
> + * @hwirq: HW interrupt number
> + *
> + * Return: Always returns 0.
> + */
> +static int xilinx_pcie_msi_map(struct irq_domain *domain, unsigned int irq,
> +			       irq_hw_number_t hwirq)
> +{
> +	irq_set_chip_and_handler(irq, &xilinx_msi_irq_chip, handle_simple_irq);
> +	irq_set_chip_data(irq, domain->host_data);
> +	set_irq_flags(irq, IRQF_VALID);
> +
> +	return 0;
> +}
> +
> +/* IRQ Domain operations */
> +static const struct irq_domain_ops msi_domain_ops = {
> +	.map = xilinx_pcie_msi_map,
> +};
> +
> +/**
> + * xilinx_pcie_enable_msi - Enable MSI support
> + * @port: PCIe port information
> + */
> +static void xilinx_pcie_enable_msi(struct xilinx_pcie_port *port)
> +{
> +	port->msg_addr = __get_free_pages(GFP_KERNEL, 0);
> +
> +	pcie_write(port, 0x0, XILINX_PCIE_REG_MSIBASE1);
> +	pcie_write(port, virt_to_phys((void *)port->msg_addr),
> +		   XILINX_PCIE_REG_MSIBASE2);
> +}
> +
> +/**
> + * xilinx_pcie_add_bus - Add MSI chip info to PCIe bus
> + * @bus: PCIe bus
> + */
> +static void xilinx_pcie_add_bus(struct pci_bus *bus)
> +{
> +	if (IS_ENABLED(CONFIG_PCI_MSI)) {
> +		struct xilinx_pcie_port *port = sys_to_pcie(bus->sysdata);
> +
> +		if (!port)
> +			return;
> +
> +		xilinx_pcie_msi_chip.dev = port->dev;
> +		bus->msi = &xilinx_pcie_msi_chip;
> +	}
> +}
> +
> +/* INTx Functions */
> +
> +/**
> + * xilinx_pcie_intx_map - Set the handler for the INTx and mark IRQ as valid
> + * @domain: IRQ domain
> + * @irq: Virtual IRQ number
> + * @hwirq: HW interrupt number
> + *
> + * Return: Always returns 0.
> + */
> +static int xilinx_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;
> +}
> +
> +/* INTx IRQ Domain operations */
> +static const struct irq_domain_ops intx_domain_ops = {
> +	.map = xilinx_pcie_intx_map,
> +};
> +
> +/* PCIe HW Functions */
> +
> +/**
> + * xilinx_pcie_intr_handler - Interrupt Service Handler
> + * @irq: IRQ number
> + * @data: PCIe port information
> + *
> + * Return: IRQ_HANDLED on success and IRQ_NONE on failure
> + */
> +static irqreturn_t xilinx_pcie_intr_handler(int irq, void *data)
> +{
> +	struct xilinx_pcie_port *port = (struct xilinx_pcie_port *)data;
> +	u32 val, mask, status, msi_data;
> +
> +	/* Read interrupt decode and mask registers */
> +	val = pcie_read(port, XILINX_PCIE_REG_IDR);
> +	mask = pcie_read(port, XILINX_PCIE_REG_IMR);
> +
> +	status = val & mask;
> +	if (!status)
> +		return IRQ_NONE;
> +
> +	if (status & XILINX_PCIE_INTR_LINK_DOWN)
> +		dev_warn(port->dev, "Link Down\n");
> +
> +	if (status & XILINX_PCIE_INTR_ECRC_ERR)
> +		dev_warn(port->dev, "ECRC failed\n");
> +
> +	if (status & XILINX_PCIE_INTR_STR_ERR)
> +		dev_warn(port->dev, "Streaming error\n");
> +
> +	if (status & XILINX_PCIE_INTR_HOT_RESET)
> +		dev_info(port->dev, "Hot reset\n");
> +
> +	if (status & XILINX_PCIE_INTR_CFG_TIMEOUT)
> +		dev_warn(port->dev, "ECAM access timeout\n");
> +
> +	if (status & XILINX_PCIE_INTR_CORRECTABLE) {
> +		dev_warn(port->dev, "Correctable error message\n");
> +		xilinx_pcie_clear_err_interrupts(port);
> +	}
> +
> +	if (status & XILINX_PCIE_INTR_NONFATAL) {
> +		dev_warn(port->dev, "Non fatal error message\n");
> +		xilinx_pcie_clear_err_interrupts(port);
> +	}
> +
> +	if (status & XILINX_PCIE_INTR_FATAL) {
> +		dev_warn(port->dev, "Fatal error message\n");
> +		xilinx_pcie_clear_err_interrupts(port);
> +	}
> +
> +	if (status & XILINX_PCIE_INTR_INTX) {
> +		/* INTx interrupt received */
> +		val = pcie_read(port, XILINX_PCIE_REG_RPIFR1);
> +
> +		/* Check whether interrupt valid */
> +		if (!(val & XILINX_PCIE_RPIFR1_INTR_VALID)) {
> +			dev_warn(port->dev, "RP Intr FIFO1 read error\n");
> +			return IRQ_HANDLED;
> +		}
> +
> +		/* Clear interrupt FIFO register 1 */
> +		pcie_write(port, XILINX_PCIE_RPIFR1_ALL_MASK,
> +			   XILINX_PCIE_REG_RPIFR1);
> +
> +		/* Handle INTx Interrupt */
> +		val = ((val & XILINX_PCIE_RPIFR1_INTR_MASK) >>
> +			XILINX_PCIE_RPIFR1_INTR_SHIFT) + 1;
> +		generic_handle_irq(irq_find_mapping(port->irq_domain, val));
> +	}
> +
> +	if (status & XILINX_PCIE_INTR_MSI) {
> +		/* MSI Interrupt */
> +		val = pcie_read(port, XILINX_PCIE_REG_RPIFR1);
> +
> +		if (!(val & XILINX_PCIE_RPIFR1_INTR_VALID)) {
> +			dev_warn(port->dev, "RP Intr FIFO1 read error\n");
> +			return IRQ_HANDLED;
> +		}
> +
> +		if (val & XILINX_PCIE_RPIFR1_MSI_INTR) {
> +			msi_data = pcie_read(port, XILINX_PCIE_REG_RPIFR2) &
> +				   XILINX_PCIE_RPIFR2_MSG_DATA;
> +
> +			/* Clear interrupt FIFO register 1 */
> +			pcie_write(port, XILINX_PCIE_RPIFR1_ALL_MASK,
> +				   XILINX_PCIE_REG_RPIFR1);
> +
> +			if (IS_ENABLED(CONFIG_PCI_MSI)) {
> +				/* Handle MSI Interrupt */
> +				generic_handle_irq(msi_data);
> +			}
> +		}
> +	}
> +
> +	if (status & XILINX_PCIE_INTR_SLV_UNSUPP)
> +		dev_warn(port->dev, "Slave unsupported request\n");
> +
> +	if (status & XILINX_PCIE_INTR_SLV_UNEXP)
> +		dev_warn(port->dev, "Slave unexpected completion\n");
> +
> +	if (status & XILINX_PCIE_INTR_SLV_COMPL)
> +		dev_warn(port->dev, "Slave completion timeout\n");
> +
> +	if (status & XILINX_PCIE_INTR_SLV_ERRP)
> +		dev_warn(port->dev, "Slave Error Poison\n");
> +
> +	if (status & XILINX_PCIE_INTR_SLV_CMPABT)
> +		dev_warn(port->dev, "Slave Completer Abort\n");
> +
> +	if (status & XILINX_PCIE_INTR_SLV_ILLBUR)
> +		dev_warn(port->dev, "Slave Illegal Burst\n");
> +
> +	if (status & XILINX_PCIE_INTR_MST_DECERR)
> +		dev_warn(port->dev, "Master decode error\n");
> +
> +	if (status & XILINX_PCIE_INTR_MST_SLVERR)
> +		dev_warn(port->dev, "Master slave error\n");
> +
> +	if (status & XILINX_PCIE_INTR_MST_ERRP)
> +		dev_warn(port->dev, "Master error poison\n");
> +
> +	/* Clear the Interrupt Decode register */
> +	pcie_write(port, status, XILINX_PCIE_REG_IDR);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +/**
> + * xilinx_pcie_free_irq_domain - Free IRQ domain
> + * @port: PCIe port information
> + */
> +static void xilinx_pcie_free_irq_domain(struct xilinx_pcie_port *port)
> +{
> +	int i;
> +	u32 irq, num_irqs;
> +
> +	/* Free IRQ Domain */
> +	if (IS_ENABLED(CONFIG_PCI_MSI)) {
> +		free_pages(port->msg_addr, 0);
> +
> +		num_irqs = XILINX_NUM_MSI_IRQS;
> +	} else {
> +		/* INTx */
> +		num_irqs = 4;
> +	}
> +
> +	for (i = 0; i < num_irqs; i++) {
> +		irq = irq_find_mapping(port->irq_domain, i);
> +		if (irq > 0)
> +			irq_dispose_mapping(irq);
> +	}
> +
> +	irq_domain_remove(port->irq_domain);
> +}
> +
> +/**
> + * xilinx_pcie_init_irq_domain - Initialize IRQ domain
> + * @port: PCIe port information
> + *
> + * Return: '0' on success and error value on failure
> + */
> +static int xilinx_pcie_init_irq_domain(struct xilinx_pcie_port *port)
> +{
> +	struct device *dev = port->dev;
> +	struct device_node *node = dev->of_node;
> +
> +	if (IS_ENABLED(CONFIG_PCI_MSI)) {
> +		/* Setup MSI */
> +		int i;
> +
> +		port->irq_domain = irq_domain_add_linear(node,
> +							 XILINX_NUM_MSI_IRQS,
> +							 &msi_domain_ops,
> +							 &xilinx_pcie_msi_chip);
> +		if (!port->irq_domain) {
> +			dev_err(dev, "Failed to get a MSI IRQ domain\n");
> +			return PTR_ERR(port->irq_domain);
> +		}
> +
> +		for (i = 0; i < XILINX_NUM_MSI_IRQS; i++)
> +			irq_create_mapping(port->irq_domain, i);
> +
> +		xilinx_pcie_enable_msi(port);
> +	} else {

This means that you can't set up INTx if CONFIG_PCI_MSI is defined.  Is
that what you want?  The hardware doesn't know whether we have
CONFIG_PCI_MSI defined, of course, so I would think it would still support
INTx either way.

> +		/* Setup INTx */
> +		struct device_node *pcie_intc_node =
> +				 of_get_next_child(node, NULL);
> +
> +		if (!pcie_intc_node) {
> +			dev_err(dev, "No PCIe Intc node found\n");
> +			return PTR_ERR(pcie_intc_node);
> +		}
> +
> +		port->irq_domain = irq_domain_add_linear(pcie_intc_node, 4,
> +							 &intx_domain_ops,
> +							 port);
> +		if (!port->irq_domain) {
> +			dev_err(dev, "Failed to get a INTx IRQ domain\n");
> +			return PTR_ERR(port->irq_domain);
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +/**
> + * xilinx_pcie_init_port - Initialize hardware
> + * @port: PCIe port information
> + */
> +static void xilinx_pcie_init_port(struct xilinx_pcie_port *port)
> +{
> +	/* Check if PCIe link is up? */

Superfluous comment, since it's obvious from the function name and dev_info
text.

> +	port->link_up = xilinx_pcie_is_link_up(port);
> +	if (!port->link_up)
> +		dev_info(port->dev, "PCIe Link is DOWN\n");
> +	else
> +		dev_info(port->dev, "PCIe Link is UP\n");
> +
> +	/* Disable all interrupts*/
> +	pcie_write(port, ~XILINX_PCIE_IDR_ALL_MASK,
> +		   XILINX_PCIE_REG_IMR);
> +
> +	/* Clear pending interrupts */
> +	pcie_write(port, pcie_read(port, XILINX_PCIE_REG_IDR) &
> +			 XILINX_PCIE_IMR_ALL_MASK,
> +		   XILINX_PCIE_REG_IDR);
> +
> +	/* Enable all interrupts*/
> +	pcie_write(port, XILINX_PCIE_IMR_ALL_MASK, XILINX_PCIE_REG_IMR);
> +
> +	/* Enable the Bridge enable bit */
> +	pcie_write(port, pcie_read(port, XILINX_PCIE_REG_RPSC) |
> +			 XILINX_PCIE_REG_RPSC_BEN,
> +		   XILINX_PCIE_REG_RPSC);
> +}
> +
> +/**
> + * xilinx_pcie_setup - Setup memory resources
> + * @nr: Bus number
> + * @sys: Per controller structure
> + *
> + * Return: '1' on success and error value on failure
> + */
> +static int xilinx_pcie_setup(int nr, struct pci_sys_data *sys)
> +{
> +	struct xilinx_pcie_port *port = sys_to_pcie(sys);
> +	struct device *dev = port->dev;
> +	struct device_node *node = dev->of_node;
> +	struct resource *mem;
> +	resource_size_t offset;
> +	struct of_pci_range_parser parser;
> +	struct of_pci_range range;
> +	struct pci_host_bridge_window *win;
> +	int err = 0, mem_resno = 0;
> +
> +	/* Get the ranges */
> +	if (of_pci_range_parser_init(&parser, node)) {
> +		dev_err(dev, "missing \"ranges\" property\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Parse the ranges and add the resources found to the list */
> +	for_each_of_pci_range(&parser, &range) {
> +
> +		if (mem_resno >= XILINX_MAX_NUM_RESOURCES) {
> +			dev_err(dev, "Maximum memory resources exceeded\n");
> +			return -EINVAL;
> +		}
> +
> +		mem = devm_kmalloc(dev, sizeof(*mem), GFP_KERNEL);
> +		if (!mem) {
> +			err = -ENOMEM;
> +			goto free_resources;
> +		}
> +
> +		of_pci_range_to_resource(&range, node, mem);
> +
> +		switch (mem->flags & IORESOURCE_TYPE_BITS) {
> +		case IORESOURCE_MEM:
> +			offset = range.cpu_addr - range.pci_addr;
> +			mem_resno++;
> +			break;
> +		default:
> +			err = -EINVAL;
> +			break;
> +		}
> +
> +		if (err < 0) {
> +			dev_warn(dev, "Invalid resource found\n");

It'd be nice for debugging to print something useful here, e.g,
%pR of "mem".

> +			continue;
> +		}
> +
> +		err = request_resource(&iomem_resource, mem);
> +		if (err)
> +			goto free_resources;
> +
> +		pci_add_resource_offset(&sys->resources, mem, offset);
> +	}
> +
> +	return 1;
> +
> +free_resources:
> +	release_child_resources(&iomem_resource);
> +	list_for_each_entry(win, &sys->resources, list)
> +		devm_kfree(dev, win->res);
> +	pci_free_resource_list(&sys->resources);
> +
> +	return err;
> +}
> +
> +/**
> + * xilinx_pcie_scan_bus - Scan PCIe bus for devices
> + * @nr: Bus number
> + * @sys: Per controller structure
> + *
> + * Return: Valid Bus pointer on success and NULL on failure
> + */
> +static struct pci_bus __init *xilinx_pcie_scan_bus(int nr,
> +						   struct pci_sys_data *sys)
> +{
> +	struct xilinx_pcie_port *port = sys_to_pcie(sys);
> +	struct pci_bus *bus;
> +
> +	if (port) {
> +		port->root_busno = sys->busnr;
> +		bus = pci_scan_root_bus(port->dev, sys->busnr, &xilinx_pcie_ops,
> +					sys, &sys->resources);

I don't think you're supplying a bus number resource here, and you should.
There's a discussion about this issue in a different driver here:

http://lkml.kernel.org/r/1396261856-22465-2-git-send-email-phil.edworthy at renesas.com

> +	} else {
> +		bus = NULL;
> +		BUG();
> +	}
> +
> +	return bus;
> +}
> +
> +/**
> + * xilinx_pcie_parse_dt - Parse Device tree
> + * @port: PCIe port information
> + *
> + * Return: '0' on success and error value on failure
> + */
> +static int xilinx_pcie_parse_dt(struct xilinx_pcie_port *port)
> +{
> +	struct device *dev = port->dev;
> +	struct device_node *node = dev->of_node;
> +	struct resource regs, busn;
> +	const char *type;
> +	int err;
> +
> +	/* Check for device type */
> +	type = of_get_property(node, "device_type", NULL);
> +	if (!type || strcmp(type, "pci")) {
> +		dev_err(dev, "invalid \"device_type\" %s\n", type);
> +		return -EINVAL;
> +	}
> +
> +	/* Map the register space */
> +	err = of_address_to_resource(node, 0, &regs);
> +	if (err) {
> +		dev_err(dev, "missing \"reg\" property\n");
> +		return err;
> +	}
> +
> +	port->reg_base = devm_ioremap_resource(dev, &regs);
> +	if (IS_ERR(port->reg_base))
> +		return PTR_ERR(port->reg_base);
> +
> +	/* Map IRQ */
> +	port->irq = irq_of_parse_and_map(node, 0);
> +	err = devm_request_irq(dev, port->irq, xilinx_pcie_intr_handler,
> +			       IRQF_SHARED, "xilinx-pcie", port);
> +	if (err) {
> +		dev_err(dev, "unable to request irq %d\n", port->irq);
> +		return err;
> +	}
> +
> +	/* Get the bus range */
> +	if (of_pci_parse_bus_range(node, &busn)) {
> +		u32 val = pcie_read(port, XILINX_PCIE_REG_BIR);
> +		u8 last;
> +
> +		last = (val & XILINX_PCIE_BIR_ECAM_SZ_MASK) >>
> +			XILINX_PCIE_BIR_ECAM_SZ_SHIFT;
> +
> +		busn = (struct resource) {
> +			.name	= node->name,
> +			.start	= 0,
> +			.end	= last,
> +			.flags	= IORESOURCE_BUS,
> +		};

This doesn't actually *do* anything, does it?  You're filling in "busn",
but that's just a local variable, and I don't see that you save the
information anywhere.

> +	}
> +
> +	return 0;
> +}
> +
> +/**
> + * xilinx_pcie_probe - Probe function
> + * @pdev: Platform device pointer
> + *
> + * Return: '0' on success and error value on failure
> + */
> +static int xilinx_pcie_probe(struct platform_device *pdev)
> +{
> +	struct xilinx_pcie_port *port;
> +	struct hw_pci hw;
> +	struct device *dev = &pdev->dev;
> +	int err;
> +
> +	if (!dev->of_node)
> +		return -ENODEV;
> +
> +	port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
> +	if (!port)
> +		return -ENOMEM;
> +
> +	port->dev = dev;
> +
> +	/* Parse the device tree */

All the comments here are superfluous.

> +	err = xilinx_pcie_parse_dt(port);
> +	if (err) {
> +		dev_err(dev, "Parsing DT failed\n");
> +		return err;
> +	}
> +
> +	/* Initialize the hardware */
> +	xilinx_pcie_init_port(port);
> +
> +	/* Setup IRQ Domain */
> +	err = xilinx_pcie_init_irq_domain(port);
> +	if (err) {
> +		dev_err(dev, "Failed creating IRQ Dommain\n");
> +		return err;
> +	}
> +
> +	/* Initialize hw_pci structure */
> +	memset(&hw, 0, sizeof(hw));
> +	hw = (struct hw_pci) {
> +		.nr_controllers	= 1,
> +		.private_data	= (void **)&port,
> +		.setup		= xilinx_pcie_setup,
> +		.map_irq	= of_irq_parse_and_map_pci,
> +		.add_bus	= xilinx_pcie_add_bus,
> +		.scan		= xilinx_pcie_scan_bus,
> +		.ops		= &xilinx_pcie_ops,
> +	};
> +
> +	/* Register the device */
> +	pci_common_init_dev(dev, &hw);
> +
> +	platform_set_drvdata(pdev, port);
> +
> +	return 0;
> +}
> +
> +/**
> + * xilinx_pcie_remove - Remove function
> + * @pdev: Platform device pointer
> + *
> + * Return: '0' always
> + */
> +static int xilinx_pcie_remove(struct platform_device *pdev)
> +{
> +	struct xilinx_pcie_port *port = platform_get_drvdata(pdev);
> +
> +	xilinx_pcie_free_irq_domain(port);
> +
> +	return 0;
> +}
> +
> +static struct of_device_id xilinx_pcie_of_match[] = {
> +	{ .compatible = "xlnx,axi-pcie-host-1.00.a" ,},

The "," inside the closing brace look unnecessary, but if you want to keep
it, the space should go after the comma instead of before it.

> +	{}
> +};
> +
> +static struct platform_driver xilinx_pcie_driver = {
> +	.driver = {
> +		.name = "xilinx-pcie",
> +		.owner = THIS_MODULE,
> +		.of_match_table = xilinx_pcie_of_match,
> +		.suppress_bind_attrs = true,
> +	},
> +	.probe = xilinx_pcie_probe,
> +	.remove = xilinx_pcie_remove,
> +};
> +module_platform_driver(xilinx_pcie_driver);
> +
> +MODULE_AUTHOR("Xilinx Inc");
> +MODULE_DESCRIPTION("Xilinx AXI PCIe driver");
> +MODULE_LICENSE("GPLv2");
> -- 
> 1.7.9.5
>