Re: [PATCH v6 2/3] PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP driver

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Tue, Feb 27, 2018 at 07:20:24AM -0500, Subrahmanya Lingappa wrote:
> Adds driver for Mobiveil AXI PCIe Host Bridge Soft IP -
> GPEX 4.0, a PCIe gen4 IP. This IP has upto 8
> outbound and inbound windows for the address translation.
> 
> Signed-off-by: Subrahmanya Lingappa <l.subrahmanya@mobiveil.co.in>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Cc: Marc Zyngier <marc.zyngier@arm.com>
> Cc: linux-pci@vger.kernel.org
> Cc: devicetree@vger.kernel.org
> ---
>  drivers/pci/host/pcie-mobiveil.c | 692 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 692 insertions(+)
>  create mode 100644 drivers/pci/host/pcie-mobiveil.c
> 
> diff --git a/drivers/pci/host/pcie-mobiveil.c b/drivers/pci/host/pcie-mobiveil.c
> new file mode 100644
> index 0000000..4270387
> --- /dev/null
> +++ b/drivers/pci/host/pcie-mobiveil.c
> @@ -0,0 +1,692 @@
> +/*
> + * PCIe host controller driver for Mobiveil PCIe Host controller
> + *
> + * SPDX-License-Identifier: GPL-2.0
> + * Copyright (c) 2017 Mobiveil Inc.
> + * Author: Subrahmanya Lingappa <l.subrahmanya@mobiveil.co.in>
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/init.h>

Nit: swap init.h and interrupt.h, alphabetical order.

[...]

> +/* supported number of interrupts */
> +#define PCI_NUM_INTX    4

It is already defined in PCI includes, remove it.

> +#define PAB_INTA_POS    5
                       ^^^^
This ought to be a tab.

> +/* outbound and inbound window definitions */
> +#define WIN_NUM_0		0
> +#define WIN_NUM_1		1
> +#define CFG_WINDOW_TYPE		0
> +#define IO_WINDOW_TYPE		1
> +#define MEM_WINDOW_TYPE		2
> +#define IB_WIN_SIZE		(256 * 1024 * 1024 * 1024)
> +#define MAX_PIO_WINDOWS		8
> +
> +/* Parameters for the waiting for link up routine */
> +#define LINK_WAIT_MAX_RETRIES	10
> +#define LINK_WAIT_MIN		90000
> +#define LINK_WAIT_MAX		100000
> +
> +struct mobiveil_pcie {
> +	struct platform_device *pdev;
> +	struct list_head resources;
> +	void __iomem *config_axi_slave_base;	/* endpoint config base */
> +	void __iomem *csr_axi_slave_base;   /* root port config base */
					^^^^

A tab please.

> +	void __iomem *pcie_reg_base;    /* Physical PCIe Controller Base */
Ditto.

> +	struct irq_domain *intx_domain;
> +	raw_spinlock_t intx_mask_lock;
> +	int irq;
> +	int apio_wins;
> +	int ppio_wins;
> +	int ob_wins_configured;	/*  configured outbound windows */
> +	int ib_wins_configured;	/*  configured inbound windows */
> +	struct resource *ob_io_res;
> +	char root_bus_nr;
> +};
> +
> +static inline void csr_writel(struct mobiveil_pcie *pcie, const u32 value,
> +		const u32 reg)
> +{
> +	writel_relaxed(value, pcie->csr_axi_slave_base + reg);
> +}
> +
> +static inline u32 csr_readl(struct mobiveil_pcie *pcie,	const u32 reg)
> +{
> +	return readl_relaxed(pcie->csr_axi_slave_base + reg);
> +}
> +
> +/*
> + * Routine to check the downstream link status, its recommended to
> + * check the link status before accessing downstream config resources.
> + */
> +static bool mobiveil_pcie_link_up(struct mobiveil_pcie *pcie)
> +{
> +	return (csr_readl(pcie, LTSSM_STATUS) &
> +		LTSSM_STATUS_L0_MASK) == LTSSM_STATUS_L0;
> +}
> +
> +static bool mobiveil_pcie_valid_device(struct pci_bus *bus, unsigned int devfn)
> +{
> +	struct mobiveil_pcie *pcie = bus->sysdata;
> +
> +	/* Check if link is up when trying to access downstream ports */
> +	if (bus->number != pcie->root_bus_nr)
> +		if (!mobiveil_pcie_link_up(pcie))

Do you really need this racy check ? Bjorn wants to remove it
from other drivers - what happens on surprise link loss on
your platform ?

> +			return false;
> +
> +	/* Only one device down on each root port */
> +	if ((bus->number == pcie->root_bus_nr) && (devfn > 0))
> +		return false;
> +
> +	/*
> +	 * Do not read more than one device on the bus directly
> +	 * attached to RC
> +	 */
> +	if ((bus->primary == pcie->root_bus_nr) && (devfn > 0))
> +		return false;
> +
> +	return true;
> +}
> +
> +/*
> + * mobiveil_pcie_map_bus - routine to get the configuration base of either
> + * root port or endpoint
> + */
> +static void __iomem *mobiveil_pcie_map_bus(struct pci_bus *bus,
> +					unsigned int devfn, int where)
> +{
> +	struct mobiveil_pcie *pcie = bus->sysdata;
> +
> +	if (!mobiveil_pcie_valid_device(bus, devfn))
> +		return NULL;
> +
> +	if (bus->number == pcie->root_bus_nr) {
> +		/* RC config access */
> +		return pcie->csr_axi_slave_base + where;
> +	} else {
> +		/*
> +		 * EP config access (in Config/APIO space)
> +		 * Program PEX Address base (31..16 bits) with appropriate value
> +		 * (BDF) in PAB_AXI_AMAP_PEX_WIN_L0 Register.
> +		 * Relies on pci_lock serialization
> +		 */
> +		csr_writel(pcie,
> +			bus->number << PAB_BUS_SHIFT |
> +			PCI_SLOT(devfn) << PAB_DEVICE_SHIFT |
> +			PCI_FUNC(devfn) << PAB_FUNCTION_SHIFT,
> +			PAB_AXI_AMAP_PEX_WIN_L(WIN_NUM_0));
> +		return pcie->config_axi_slave_base + where;
> +	}
> +}
> +
> +static struct pci_ops mobiveil_pcie_ops = {
> +	.map_bus = mobiveil_pcie_map_bus,
> +	.read = pci_generic_config_read,
> +	.write = pci_generic_config_write,
> +};
> +
> +static void mobiveil_pcie_isr(struct irq_desc *desc)
> +{
> +	struct irq_chip *chip = irq_desc_get_chip(desc);
> +	struct mobiveil_pcie *pcie = irq_desc_get_handler_data(desc);
> +	struct device *dev = &pcie->pdev->dev;
> +	unsigned long shifted_status;
> +	u32 bit, virq;
> +	u32 val, mask;

Nit: why two lines for same type.

> +	/*
> +	 * The core provides a single interrupt for both INTx/MSI messages.
> +	 * So we'll read both INTx and MSI status

Add a comment for INTX and update it in the next patch. This patch
only deals with INTX and the comment should reflect that.

> +	 */
> +
> +	chained_irq_enter(chip, desc);
> +
> +	/* read INTx status */
> +	val = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT);
> +	mask = csr_readl(pcie, PAB_INTP_AMBA_MISC_ENB);
> +	intr_status = val & mask;
> +
> +	/* Handle INTx */
> +	if (intr_status & PAB_INTP_INTX_MASK) {
> +		shifted_status = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT) >>
> +			PAB_INTA_POS;
> +		do {
> +			for_each_set_bit(bit, &shifted_status, PCI_NUM_INTX) {
> +				virq = irq_find_mapping(pcie->intx_domain,
> +						bit + 1);

It must be bit, not bit + 1. See DT bindings comment.

> +				if (virq)
> +					generic_handle_irq(virq);
> +				else
> +					dev_err_ratelimited(dev,
> +						"unexpected IRQ, INT%d\n", bit);
> +
> +				/* clear interrupt */
> +				csr_writel(pcie, shifted_status << PAB_INTA_POS,
> +						PAB_INTP_AMBA_MISC_STAT);
> +			}
> +		} while ((shifted_status >>  PAB_INTA_POS) != 0);
> +	}
> +
> +	/* Clear the interrupt status */
> +	csr_writel(pcie, intr_status, PAB_INTP_AMBA_MISC_STAT);
> +	chained_irq_exit(chip, desc);
> +}
> +
> +static int mobiveil_pcie_parse_dt(struct mobiveil_pcie *pcie)
> +{
> +	struct device *dev = &pcie->pdev->dev;
> +	struct platform_device *pdev = pcie->pdev;
> +	struct device_node *node = dev->of_node;
> +	struct resource *res;
> +	const char *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 config resource */
> +	res = platform_get_resource_byname(pdev,
> +		IORESOURCE_MEM, "config_axi_slave");

What can fit in a line should stay in a line, so update this wrapping.

	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
					   "config_axi_slave");

> +	pcie->config_axi_slave_base = devm_pci_remap_cfg_resource(dev, res);
> +	if (IS_ERR(pcie->config_axi_slave_base))
> +		return PTR_ERR(pcie->config_axi_slave_base);
> +	pcie->ob_io_res = res;
> +
> +	/* map csr resource */
> +	res = platform_get_resource_byname(pdev,
> +		IORESOURCE_MEM, "csr_axi_slave");

	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
					   "csr_axi_slave");

> +	pcie->csr_axi_slave_base = devm_pci_remap_cfg_resource(dev, res);
> +	if (IS_ERR(pcie->csr_axi_slave_base))
> +		return PTR_ERR(pcie->csr_axi_slave_base);
> +	pcie->pcie_reg_base = res->start;
> +
> +	/* read the number of windows requested */
> +	if (of_property_read_u32(node, "apio-wins", &pcie->apio_wins))
> +		pcie->apio_wins = MAX_PIO_WINDOWS;
> +
> +	if (of_property_read_u32(node, "ppio-wins", &pcie->ppio_wins))
> +		pcie->ppio_wins = MAX_PIO_WINDOWS;
> +
> +	pcie->irq = platform_get_irq(pdev, 0);
> +	if (pcie->irq <= 0) {
> +		dev_err(dev, "failed to map IRQ: %d\n", pcie->irq);
> +		return -ENODEV;
> +	}
> +
> +	irq_set_chained_handler_and_data(pcie->irq, mobiveil_pcie_isr, pcie);
> +
> +	return 0;
> +}
> +
> +/*
> + * select_paged_register - routine to access paged register of root complex
> + *
> + * registers of RC are paged, for this scheme to work
> + * extracted higher 6 bits of the offset will be written to pg_sel
> + * field of PAB_CTRL register and rest of the lower 10 bits enabled with
> + * PAGE_SEL_EN are used as offset of the register.
> + *
> + */
> +static void select_paged_register(struct mobiveil_pcie *pcie, u32 offset)
> +{
> +	int pab_ctrl_dw, pg_sel;
> +
> +	/* clear pg_sel field */
> +	pab_ctrl_dw = csr_readl(pcie, PAB_CTRL);
> +	pab_ctrl_dw = (pab_ctrl_dw & ~(PAGE_SEL_MASK << PAGE_SEL_SHIFT));
> +
> +	/* set pg_sel field */
> +	pg_sel = (offset >> PAGE_SEL_OFFSET_SHIFT) & PAGE_SEL_MASK;
> +	pab_ctrl_dw |= ((pg_sel << PAGE_SEL_SHIFT));
> +	csr_writel(pcie, pab_ctrl_dw, PAB_CTRL);
> +}
> +
> +static void write_paged_register(struct mobiveil_pcie *pcie,
> +		u32 val, u32 offset)
> +{
> +	u32 off = (offset & PAGE_LO_MASK) | PAGE_SEL_EN;
> +
> +	select_paged_register(pcie, offset);
> +	csr_writel(pcie, val, off);
> +}
> +
> +static u32 read_paged_register(struct mobiveil_pcie *pcie, u32 offset)
> +{
> +	u32 off = (offset & PAGE_LO_MASK) | PAGE_SEL_EN;
> +
> +	select_paged_register(pcie, offset);
> +	return csr_readl(pcie, off);
> +}
> +
> +static void program_ib_windows(struct mobiveil_pcie *pcie, int win_num,
> +		int pci_addr, u32 type,	int size)

size must certainly not be a signed int and must be u64, for this reason
current windows are truncated if I am not mistaken so this is a bug.

> +{
> +	int pio_ctrl_val;
> +	int amap_ctrl_dw;
> +	u64 size64 =  ~(size-1);

Nit: 1 space before ~ is enough and you should add on both sides of
the minus sign (-).

I think you should round it though.

u64 mask = (1ULL << fls(size - 1)) - 1;

(mask or whatever you may call it)

> +
> +	if ((pcie->ib_wins_configured + 1) > pcie->ppio_wins) {
> +		dev_err(&pcie->pdev->dev,
> +			"ERROR: max inbound windows reached !\n");
> +		return;
> +	}
> +
> +	pio_ctrl_val = csr_readl(pcie, PAB_PEX_PIO_CTRL);
> +	csr_writel(pcie,
> +		pio_ctrl_val | (1 << PIO_ENABLE_SHIFT), PAB_PEX_PIO_CTRL);
> +	amap_ctrl_dw =	read_paged_register(pcie, PAB_PEX_AMAP_CTRL(win_num));
> +	amap_ctrl_dw = (amap_ctrl_dw | (type << AMAP_CTRL_TYPE_SHIFT));
> +	amap_ctrl_dw = (amap_ctrl_dw | (1 << AMAP_CTRL_EN_SHIFT));
> +
> +	write_paged_register(pcie, amap_ctrl_dw | lower_32_bits(size64),
> +				PAB_PEX_AMAP_CTRL(win_num));
> +
> +	write_paged_register(pcie, upper_32_bits(size64),
> +				PAB_EXT_PEX_AMAP_SIZEN(win_num));
> +
> +	write_paged_register(pcie, pci_addr, PAB_PEX_AMAP_AXI_WIN(win_num));
> +	write_paged_register(pcie, pci_addr, PAB_PEX_AMAP_PEX_WIN_L(win_num));
> +	write_paged_register(pcie, 0, PAB_PEX_AMAP_PEX_WIN_H(win_num));
> +}
> +
> +/*
> + * routine to program the outbound windows
> + */
> +static void program_ob_windows(struct mobiveil_pcie *pcie, int win_num,
> +		u64 cpu_addr, u64 pci_addr, u32 config_io_bit,
> +		int size)

You have a funny way of wrapping lines, even when that's not needed,
as in the last line.

> +{
> +
> +	u32 value, type;
> +	u64 size64 =  ~(size-1);

See above.

> +	if ((pcie->ob_wins_configured + 1) > pcie->apio_wins) {
> +		dev_err(&pcie->pdev->dev,
> +			"ERROR: max outbound windows reached !\n");
> +		return;
> +	}
> +
> +	/*
> +	 * program Enable Bit to 1, Type Bit to (00) base 2, AXI Window Size Bit
> +	 * to 4 KB in PAB_AXI_AMAP_CTRL register
> +	 */
> +	type = config_io_bit;
> +	value = csr_readl(pcie, PAB_AXI_AMAP_CTRL(win_num));
> +	csr_writel(pcie,
> +			1 << WIN_ENABLE_SHIFT |

What fits in a line should stay in a line.

> +			type << WIN_TYPE_SHIFT |
> +			lower_32_bits(size64),
> +			PAB_AXI_AMAP_CTRL(win_num));

Here:
	csr_writel(pcie, 1 << WIN_ENABLE_SHIFT |
			type << WIN_TYPE_SHIFT |
			lower_32_bits(size64), PAB_AXI_AMAP_CTRL(win_num));
> +	write_paged_register(pcie, upper_32_bits(size64),
> +				PAB_EXT_AXI_AMAP_SIZE(win_num));
> +
> +	/*
> +	 * program AXI window base with appropriate value in
> +	 * PAB_AXI_AMAP_AXI_WIN0 register
> +	 */
> +	value = csr_readl(pcie, PAB_AXI_AMAP_AXI_WIN(win_num));
> +	csr_writel(pcie,
> +			cpu_addr >> AXI_WINDOW_BASE_SHIFT <<
> +			AXI_WINDOW_BASE_SHIFT, PAB_AXI_AMAP_AXI_WIN(win_num));

Can you explain to me what this >> << is there for ?

> +	value = csr_readl(pcie, PAB_AXI_AMAP_PEX_WIN_H(win_num));
> +
> +	csr_writel(pcie, lower_32_bits(pci_addr),
> +			PAB_AXI_AMAP_PEX_WIN_L(win_num));
> +	csr_writel(pcie, upper_32_bits(pci_addr),
> +			PAB_AXI_AMAP_PEX_WIN_H(win_num));
> +
> +	pcie->ob_wins_configured++;
> +}
> +
> +static int mobiveil_bringup_link(struct mobiveil_pcie *pcie)
> +{
> +	int retries;
> +
> +	/* check if the link is up or not */
> +	for (retries = 0; retries < LINK_WAIT_MAX_RETRIES; retries++) {
> +		if (mobiveil_pcie_link_up(pcie))
> +			return 0;
> +
> +		usleep_range(LINK_WAIT_MIN, LINK_WAIT_MAX);
> +	}
> +	dev_err(&pcie->pdev->dev, "link never came up\n");
> +	return -ETIMEDOUT;
> +}
> +
> +static int mobiveil_host_init(struct mobiveil_pcie *pcie)
> +{
> +	u32 value;
> +	u32 type = 0;
> +	u32 pab_ctrl;

Why do you need three lines for the same type ?

> +	int err;
> +	struct resource_entry *win, *tmp;
> +
> +	err = mobiveil_bringup_link(pcie);
> +	if (err) {
> +		dev_info(&pcie->pdev->dev, "link bring-up failed\n");
> +		return err;
> +	}
> +
> +	/*
> +	 * program Bus Master Enable Bit in Command Register in PAB Config
> +	 * Space
> +	 */
> +	value = csr_readl(pcie, PCI_COMMAND);
> +	csr_writel(pcie, value | PCI_COMMAND_IO | PCI_COMMAND_MEMORY |
> +		PCI_COMMAND_MASTER,	PCI_COMMAND);
				   ^

Tab not needed, just a space.

> +	/*
> +	 * program PIO Enable Bit to 1 (and PEX PIO Enable to 1) in PAB_CTRL
> +	 * register
> +	 */
> +	pab_ctrl = csr_readl(pcie, PAB_CTRL);
> +	csr_writel(pcie, pab_ctrl | (1 << AMBA_PIO_ENABLE_SHIFT) |
> +		(1 << PEX_PIO_ENABLE_SHIFT),
> +		PAB_CTRL);
> +
> +	csr_writel(pcie, (PAB_INTP_INTX_MASK | PAB_INTP_MSI_MASK),
> +		PAB_INTP_AMBA_MISC_ENB);
> +
> +	/* program PIO Enable Bit to 1 and Config Window Enable Bit to 1 in
> +	 * PAB_AXI_PIO_CTRL Register
> +	 */
> +	value = csr_readl(pcie, PAB_AXI_PIO_CTRL);
> +	csr_writel(pcie, value | APIO_EN_MASK, PAB_AXI_PIO_CTRL);
> +
> +	/*
> +	 * we'll program one outbound window for config reads and
> +	 * another default inbound window for all the upstream traffic
> +	 * rest of the outbound windows will be configured according to
> +	 * the "ranges" field defined in device tree
> +	 */
> +
> +	/* config outbound translation window */
> +	program_ob_windows(pcie, pcie->ob_wins_configured,
> +			pcie->ob_io_res->start,	0, CFG_WINDOW_TYPE,
> +			resource_size(pcie->ob_io_res));
> +
> +	/* memory inbound  translation window */
> +	program_ib_windows(pcie, WIN_NUM_1, 0, MEM_WINDOW_TYPE, IB_WIN_SIZE);
> +
> +	/* Get the I/O and memory ranges from DT */
> +	resource_list_for_each_entry_safe(win, tmp, &pcie->resources) {
> +		type = 0;
> +		if (resource_type(win->res) == IORESOURCE_MEM)
> +			type = MEM_WINDOW_TYPE;
> +		if (resource_type(win->res) == IORESOURCE_IO)
> +			type = IO_WINDOW_TYPE;
> +		if (type) {
> +			/* configure outbound translation window */
> +			program_ob_windows(pcie, pcie->ob_wins_configured,
> +				win->res->start, 0, type,
> +				resource_size(win->res));
> +		}
> +	}
> +
> +	return err;
> +}
> +
> +static void mobiveil_mask_intx_irq(struct irq_data *data)
> +{
> +	struct irq_desc *desc = irq_to_desc(data->irq);
> +	struct mobiveil_pcie *pcie;
> +	unsigned long flags;
> +	u32 mask;
> +	u32 shifted_val;

All u32 variables in one line please.

> +	pcie = irq_desc_get_chip_data(desc);
> +	mask = 1 << ((data->hwirq + PAB_INTA_POS) - 1);
> +	raw_spin_lock_irqsave(&pcie->intx_mask_lock, flags);
> +	shifted_val = csr_readl(pcie, PAB_INTP_AMBA_MISC_ENB);
> +	csr_writel(pcie, (shifted_val & (~mask)), PAB_INTP_AMBA_MISC_ENB);
> +	raw_spin_unlock_irqrestore(&pcie->intx_mask_lock, flags);
> +}
> +
> +static void mobiveil_unmask_intx_irq(struct irq_data *data)
> +{
> +	struct irq_desc *desc = irq_to_desc(data->irq);
> +	struct mobiveil_pcie *pcie;
> +	unsigned long flags;
> +	u32 shifted_val;
> +	u32 mask;

All u32 in one line.

> +
> +	pcie = irq_desc_get_chip_data(desc);
> +	mask = 1 << ((data->hwirq + PAB_INTA_POS) - 1);
> +	raw_spin_lock_irqsave(&pcie->intx_mask_lock, flags);
> +	shifted_val = csr_readl(pcie, PAB_INTP_AMBA_MISC_ENB);
> +	csr_writel(pcie, (shifted_val | mask), PAB_INTP_AMBA_MISC_ENB);
> +	raw_spin_unlock_irqrestore(&pcie->intx_mask_lock, flags);
> +}
> +
> +static struct irq_chip intx_irq_chip = {
> +	.name = "mobiveil_pcie:intx",
> +	.irq_enable = mobiveil_unmask_intx_irq,
> +	.irq_disable = mobiveil_mask_intx_irq,
> +	.irq_mask = mobiveil_mask_intx_irq,
> +	.irq_unmask = mobiveil_unmask_intx_irq,
> +};
> +
> +/* routine to setup the INTx related data */
> +static int mobiveil_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
> +		irq_hw_number_t hwirq)
> +{
> +	irq_set_chip_and_handler(irq, &intx_irq_chip, handle_simple_irq);
> +	irq_set_chip_data(irq, domain->host_data);
> +	return 0;
> +}
> +
> +/* INTx domain operations structure */
> +static const struct irq_domain_ops intx_domain_ops = {
> +	.map = mobiveil_pcie_intx_map,
> +	.xlate = pci_irqd_intx_xlate,

I do not think you need this xlate if you follow what's discussed in DT
bindings.

> +};
> +
> +static int mobiveil_pcie_init_irq_domain(struct mobiveil_pcie *pcie)
> +{
> +	struct device *dev = &pcie->pdev->dev;
> +	struct device_node *node = dev->of_node;
> +	int ret;
> +
> +	/* setup INTx */
> +	pcie->intx_domain = irq_domain_add_linear(node,
> +				PCI_NUM_INTX + 1, &intx_domain_ops, pcie);

Remove (+1).

> +	if (!pcie->intx_domain) {
> +		dev_err(dev, "Failed to get a INTx IRQ domain\n");
> +		return -ENODEV;
> +	}
> +
> +	raw_spin_lock_init(&pcie->intx_mask_lock);
> +
> +	return 0;
> +}
> +
> +static int mobiveil_pcie_probe(struct platform_device *pdev)
> +{
> +	struct mobiveil_pcie *pcie;
> +	struct pci_bus *bus;
> +	struct pci_bus *child;
> +	struct pci_host_bridge *bridge;
> +	struct device *dev = &pdev->dev;
> +	struct device_node *node = dev->of_node;
> +	resource_size_t iobase;
> +	int ret;
> +
> +	/* allocate the PCIe port */
> +	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
> +	if (!bridge)
> +		return -ENODEV;
> +
> +	pcie = pci_host_bridge_priv(bridge);
> +	if (!pcie)
> +		return -ENOMEM;
> +
> +	pcie->pdev = pdev;
> +
> +	ret = mobiveil_pcie_parse_dt(pcie);
> +	if (ret) {
> +		dev_err(dev, "Parsing DT failed, ret: %x\n", ret);
> +		return ret;
> +	}
> +
> +	INIT_LIST_HEAD(&pcie->resources);
> +
> +	/* parse the host bridge base addresses from the device tree file */
> +	ret = of_pci_get_host_bridge_resources(node,
> +			0, 0xff, &pcie->resources, &iobase);
> +	if (ret) {
> +		dev_err(dev, "Getting bridge resources failed\n");
> +		return -ENOMEM;
> +	}
> +
> +	/*
> +	 * configure all inbound and outbound windows and prepare the RC for
> +	 * config access
> +	 */
> +	ret = mobiveil_host_init(pcie);
> +	if (ret) {
> +		dev_err(dev, "Failed to initialize host\n");
> +		goto error;
> +	}
> +
> +	/* fixup for PCIe class register */
> +	csr_writel(pcie, 0x060402ab, PAB_INTP_AXI_PIO_CLASS);
> +
> +	/* initialize the IRQ domains */
> +	ret = mobiveil_pcie_init_irq_domain(pcie);
> +	if (ret) {
> +		dev_err(dev, "Failed creating IRQ Domain\n");
> +		goto error;
> +	}
> +
> +	ret = devm_request_pci_bus_resources(dev, &pcie->resources);
> +	if (ret)
> +		goto error;
> +
> +	/* Initialize bridge */
> +	list_splice_init(&pcie->resources, &bridge->windows);
> +	bridge->dev.parent = dev;
> +	bridge->sysdata = pcie;
> +	bridge->busnr = pcie->root_bus_nr;
> +	bridge->ops = &mobiveil_pcie_ops;
> +	bridge->map_irq = of_irq_parse_and_map_pci;
> +	bridge->swizzle_irq = pci_common_swizzle;
> +
> +	/* setup the kernel resources for the newly added PCIe root bus */
> +	ret = pci_scan_root_bus_bridge(bridge);
> +	if (ret)
> +		goto error;
> +
> +	bus = bridge->bus;
> +
> +	pci_assign_unassigned_bus_resources(bus);
> +	list_for_each_entry(child, &bus->children, node)
> +		pcie_bus_configure_settings(child);
> +	pci_bus_add_devices(bus);
> +
> +	platform_set_drvdata(pdev, pcie);

What's this needed for ?

> +	return 0;
> +error:
> +	pci_free_resource_list(&pcie->resources);
> +	return ret;
> +}
> +
> +static const struct of_device_id mobiveil_pcie_of_match[] = {
> +	{.compatible = "mbvl,gpex40-pcie",},
> +};
> +
> +MODULE_DEVICE_TABLE(of, mobiveil_pcie_of_match);
> +
> +static struct platform_driver mobiveil_pcie_driver = {
> +	.probe = mobiveil_pcie_probe,
> +	.driver = {
> +			.name = "mobiveil-pcie",
> +			.of_match_table = mobiveil_pcie_of_match,
> +			.suppress_bind_attrs = true,
> +		},
> +};
> +
> +builtin_platform_driver(mobiveil_pcie_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("Mobiveil PCIe host controller driver");
> +MODULE_AUTHOR("Subrahmanya Lingappa <l.subrahmanya@mobiveil.co.in>");

Thanks,
Lorenzo