/*
 * PCIe driver for Renesas R-Car SoCs
 *  Copyright (C) 2014 Renesas Electronics Europe Ltd
 *
 * Based on:
 *  arch/sh/drivers/pci/pcie-sh7786.c
 *  arch/sh/drivers/pci/ops-sh7786.c
 *  Copyright (C) 2009 - 2011  Paul Mundt
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2.  This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_pci.h>
#include <linux/of_platform.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#define DRV_NAME "rcar-pcie"

#define PCIECAR			0x000010
#define PCIECCTLR		0x000018
#define  CONFIG_SEND_ENABLE	(1 << 31)
#define  TYPE0			(0 << 8)
#define  TYPE1			(1 << 8)
#define PCIECDR			0x000020
#define PCIEMSR			0x000028
#define PCIEINTXR		0x000400

/* Transfer control */
#define PCIETCTLR		0x02000
#define  CFINIT			1
#define PCIETSTR		0x02004
#define  DATA_LINK_ACTIVE	1
#define PCIEERRFR		0x02020
#define  UNSUPPORTED_REQUEST	(1 << 4)

/* root port address */
#define PCIEPRAR(x)		(0x02080 + ((x) * 0x4))

/* local address reg & mask */
#define PCIELAR(x)		(0x02200 + ((x) * 0x20))
#define PCIELAMR(x)		(0x02208 + ((x) * 0x20))
#define  LAM_PREFETCH		(1 << 3)
#define  LAM_64BIT		(1 << 2)
#define  LAR_ENABLE		(1 << 1)

/* PCIe address reg & mask */
#define PCIEPARL(x)		(0x03400 + ((x) * 0x20))
#define PCIEPARH(x)		(0x03404 + ((x) * 0x20))
#define PCIEPAMR(x)		(0x03408 + ((x) * 0x20))
#define PCIEPTCTLR(x)		(0x0340c + ((x) * 0x20))
#define  PAR_ENABLE		(1 << 31)
#define  IO_SPACE		(1 << 8)

/* Configuration */
#define PCICONF(x)		(0x010000 + ((x) * 0x4))
#define PMCAP(x)		(0x010040 + ((x) * 0x4))
#define EXPCAP(x)		(0x010070 + ((x) * 0x4))
#define VCCAP(x)		(0x010100 + ((x) * 0x4))

/* link layer */
#define IDSETR1			0x011004
#define TLCTLR			0x011048
#define MACSR			0x011054
#define MACCTLR			0x011058
#define  SCRAMBLE_DISABLE	(1 << 27)

/* R-Car H1 PHY */
#define H1_PCIEPHYADRR		0x04000c
#define  WRITE_CMD		(1 << 16)
#define  PHY_ACK		(1 << 24)
#define  RATE_POS		12
#define  LANE_POS		8
#define  ADR_POS		0
#define H1_PCIEPHYDOUTR		0x040014
#define H1_PCIEPHYSR		0x040018

#define RCONF(x)	(PCICONF(0)+(x))
#define RPMCAP(x)	(PMCAP(0)+(x))
#define REXPCAP(x)	(EXPCAP(0)+(x))
#define RVCCAP(x)	(VCCAP(0)+(x))

#define  PCIE_CONF_BUS(b)	(((b) & 0xff) << 24)
#define  PCIE_CONF_DEV(d)	(((d) & 0x1f) << 19)
#define  PCIE_CONF_FUNC(f)	(((f) & 0x7) << 16)

#define PCI_MAX_RESOURCES 4
#define MAX_NR_INBOUND_MAPS 6

/* Structure representing the PCIe interface */
struct rcar_pcie {
	struct device		*dev;
	void __iomem		*base;
	struct resource		res[PCI_MAX_RESOURCES];
	struct resource		busn;
	int			root_bus_nr;
	struct clk		*clk;
	struct clk		*bus_clk;
};

static inline struct rcar_pcie *sys_to_pcie(struct pci_sys_data *sys)
{
	return sys->private_data;
}

static void pci_write_reg(struct rcar_pcie *pcie, unsigned long val,
			  unsigned long reg)
{
	writel(val, pcie->base + reg);
}

static unsigned long pci_read_reg(struct rcar_pcie *pcie, unsigned long reg)
{
	return readl(pcie->base + reg);
}

enum {
	PCI_ACCESS_READ,
	PCI_ACCESS_WRITE,
};

static void rcar_rmw32(struct rcar_pcie *pcie, int where, u32 mask, u32 data)
{
	int shift = 8 * (where & 3);
	u32 val = pci_read_reg(pcie, where & ~3);

	val &= ~(mask << shift);
	val |= data << shift;
	pci_write_reg(pcie, val, where & ~3);
}

static u32 rcar_read_conf(struct rcar_pcie *pcie, int where)
{
	int shift = 8 * (where & 3);
	u32 val = pci_read_reg(pcie, where & ~3);

	return val >> shift;
}

/* Serialization is provided by 'pci_lock' in drivers/pci/access.c */
static int rcar_pcie_config_access(struct rcar_pcie *pcie,
		unsigned char access_type, struct pci_bus *bus,
		unsigned int devfn, int where, u32 *data)
{
	int dev, func, reg, index;

	dev = PCI_SLOT(devfn);
	func = PCI_FUNC(devfn);
	reg = where & ~3;
	index = reg / 4;

	/*
	 * While each channel has its own memory-mapped extended config
	 * space, it's generally only accessible when in endpoint mode.
	 * When in root complex mode, the controller is unable to target
	 * itself with either type 0 or type 1 accesses, and indeed, any
	 * controller initiated target transfer to its own config space
	 * result in a completer abort.
	 *
	 * Each channel effectively only supports a single device, but as
	 * the same channel <-> device access works for any PCI_SLOT()
	 * value, we cheat a bit here and bind the controller's config
	 * space to devfn 0 in order to enable self-enumeration. In this
	 * case the regular ECAR/ECDR path is sidelined and the mangled
	 * config access itself is initiated as an internal bus transaction.
	 */
	if (pci_is_root_bus(bus)) {
		if (dev != 0)
			return PCIBIOS_DEVICE_NOT_FOUND;

		if (access_type == PCI_ACCESS_READ) {
			*data = pci_read_reg(pcie, PCICONF(index));
		} else {
			/* Keep an eye out for changes to the root bus number */
			if (pci_is_root_bus(bus) && (reg == PCI_PRIMARY_BUS))
				pcie->root_bus_nr = *data & 0xff;

			pci_write_reg(pcie, *data, PCICONF(index));
		}

		return PCIBIOS_SUCCESSFUL;
	}

	if (pcie->root_bus_nr < 0)
		return PCIBIOS_DEVICE_NOT_FOUND;

	/* Clear errors */
	pci_write_reg(pcie, pci_read_reg(pcie, PCIEERRFR), PCIEERRFR);

	/* Set the PIO address */
	pci_write_reg(pcie, PCIE_CONF_BUS(bus->number) | PCIE_CONF_DEV(dev) |
				PCIE_CONF_FUNC(func) | reg, PCIECAR);

	/* Enable the configuration access */
	if (bus->parent->number == pcie->root_bus_nr)
		pci_write_reg(pcie, CONFIG_SEND_ENABLE | TYPE0, PCIECCTLR);
	else
		pci_write_reg(pcie, CONFIG_SEND_ENABLE | TYPE1, PCIECCTLR);

	/* Check for errors */
	if (pci_read_reg(pcie, PCIEERRFR) & UNSUPPORTED_REQUEST)
		return PCIBIOS_DEVICE_NOT_FOUND;

	/* Check for master and target aborts */
	if (rcar_read_conf(pcie, RCONF(PCI_STATUS)) &
		(PCI_STATUS_REC_MASTER_ABORT | PCI_STATUS_REC_TARGET_ABORT))
		return PCIBIOS_DEVICE_NOT_FOUND;

	if (access_type == PCI_ACCESS_READ)
		*data = pci_read_reg(pcie, PCIECDR);
	else
		pci_write_reg(pcie, *data, PCIECDR);

	/* Disable the configuration access */
	pci_write_reg(pcie, 0, PCIECCTLR);

	return PCIBIOS_SUCCESSFUL;
}

static int rcar_pcie_read_conf(struct pci_bus *bus, unsigned int devfn,
			       int where, int size, u32 *val)
{
	struct rcar_pcie *pcie = sys_to_pcie(bus->sysdata);
	int ret;

	if ((size == 2) && (where & 1))
		return PCIBIOS_BAD_REGISTER_NUMBER;
	else if ((size == 4) && (where & 3))
		return PCIBIOS_BAD_REGISTER_NUMBER;

	ret = rcar_pcie_config_access(pcie, PCI_ACCESS_READ,
				      bus, devfn, where, val);
	if (ret != PCIBIOS_SUCCESSFUL) {
		*val = 0xffffffff;
		return ret;
	}

	if (size == 1)
		*val = (*val >> (8 * (where & 3))) & 0xff;
	else if (size == 2)
		*val = (*val >> (8 * (where & 2))) & 0xffff;

	dev_dbg(&bus->dev, "pcie-config-read: bus=%3d devfn=0x%04x "
		"where=0x%04x size=%d val=0x%08lx\n", bus->number,
		devfn, where, size, (unsigned long)*val);

	return ret;
}

/* Serialization is provided by 'pci_lock' in drivers/pci/access.c */
static int rcar_pcie_write_conf(struct pci_bus *bus, unsigned int devfn,
				int where, int size, u32 val)
{
	struct rcar_pcie *pcie = sys_to_pcie(bus->sysdata);
	int shift, ret;
	u32 data;

	if ((size == 2) && (where & 1))
		return PCIBIOS_BAD_REGISTER_NUMBER;
	else if ((size == 4) && (where & 3))
		return PCIBIOS_BAD_REGISTER_NUMBER;

	ret = rcar_pcie_config_access(pcie, PCI_ACCESS_READ,
				      bus, devfn, where, &data);
	if (ret != PCIBIOS_SUCCESSFUL)
		return ret;

	dev_dbg(&bus->dev, "pcie-config-write: bus=%3d devfn=0x%04x "
		"where=0x%04x size=%d val=0x%08lx\n", bus->number,
		devfn, where, size, (unsigned long)val);

	if (size == 1) {
		shift = 8 * (where & 3);
		data &= ~(0xff << shift);
		data |= ((val & 0xff) << shift);
	} else if (size == 2) {
		shift = 8 * (where & 2);
		data &= ~(0xffff << shift);
		data |= ((val & 0xffff) << shift);
	} else
		data = val;

	ret = rcar_pcie_config_access(pcie, PCI_ACCESS_WRITE,
				      bus, devfn, where, &data);

	return ret;
}

static struct pci_ops rcar_pcie_ops = {
	.read	= rcar_pcie_read_conf,
	.write	= rcar_pcie_write_conf,
};

static void rcar_pcie_setup_window(int win, struct resource *res,
				   struct rcar_pcie *pcie)
{
	/* Setup PCIe address space mappings for each resource */
	resource_size_t size;
	u32 mask;

	pci_write_reg(pcie, 0x00000000, PCIEPTCTLR(win));

	/*
	 * The PAMR mask is calculated in units of 128Bytes, which
	 * keeps things pretty simple.
	 */
	size = resource_size(res);
	mask = (roundup_pow_of_two(size) / SZ_128) - 1;
	pci_write_reg(pcie, mask << 7, PCIEPAMR(win));

	pci_write_reg(pcie, upper_32_bits(res->start), PCIEPARH(win));
	pci_write_reg(pcie, lower_32_bits(res->start), PCIEPARL(win));

	/* First resource is for IO */
	mask = PAR_ENABLE;
	if (res->flags & IORESOURCE_IO)
		mask |= IO_SPACE;

	pci_write_reg(pcie, mask, PCIEPTCTLR(win));
}

static int rcar_pcie_setup(int nr, struct pci_sys_data *sys)
{
	struct rcar_pcie *pcie = sys_to_pcie(sys);
	struct resource *res;
	int i;

	pcie->root_bus_nr = -1;

	/* Setup PCI resources */
	for (i = 0; i < PCI_MAX_RESOURCES; i++) {

		res = &pcie->res[i];
		if (!res->flags)
			continue;

		rcar_pcie_setup_window(i, res, pcie);

		if (res->flags & IORESOURCE_IO)
			pci_ioremap_io(nr * SZ_64K, res->start);
		else
			pci_add_resource(&sys->resources, res);
	}
	pci_add_resource(&sys->resources, &pcie->busn);

	return 1;
}

struct hw_pci rcar_pci = {
	.setup          = rcar_pcie_setup,
	.map_irq        = of_irq_parse_and_map_pci,
	.ops            = &rcar_pcie_ops,
};

static void rcar_pcie_enable(struct rcar_pcie *pcie)
{
	struct platform_device *pdev = to_platform_device(pcie->dev);

	rcar_pci.nr_controllers = 1;
	rcar_pci.private_data = (void **)&pcie;

	pci_common_init_dev(&pdev->dev, &rcar_pci);
#ifdef CONFIG_PCI_DOMAINS
	rcar_pci.domain++;
#endif
}

static int phy_wait_for_ack(struct rcar_pcie *pcie)
{
	unsigned int timeout = 100;

	while (timeout--) {
		if (pci_read_reg(pcie, H1_PCIEPHYADRR) & PHY_ACK)
			return 0;

		udelay(100);
	}

	dev_err(pcie->dev, "Access to PCIe phy timed out\n");

	return -ETIMEDOUT;
}

static void phy_write_reg(struct rcar_pcie *pcie,
				 unsigned int rate, unsigned int addr,
				 unsigned int lane, unsigned int data)
{
	unsigned long phyaddr;

	phyaddr = WRITE_CMD |
		((rate & 1) << RATE_POS) |
		((lane & 0xf) << LANE_POS) |
		((addr & 0xff) << ADR_POS);

	/* Set write data */
	pci_write_reg(pcie, data, H1_PCIEPHYDOUTR);
	pci_write_reg(pcie, phyaddr, H1_PCIEPHYADRR);

	/* Ignore errors as they will be dealt with if the data link is down */
	phy_wait_for_ack(pcie);

	/* Clear command */
	pci_write_reg(pcie, 0, H1_PCIEPHYDOUTR);
	pci_write_reg(pcie, 0, H1_PCIEPHYADRR);

	/* Ignore errors as they will be dealt with if the data link is down */
	phy_wait_for_ack(pcie);
}

static int rcar_pcie_wait_for_dl(struct rcar_pcie *pcie)
{
	unsigned int timeout = 10;

	while (timeout--) {
		if ((pci_read_reg(pcie, PCIETSTR) & DATA_LINK_ACTIVE))
			return 0;

		msleep(5);
	}

	return -ETIMEDOUT;
}

static int rcar_pcie_hw_init(struct rcar_pcie *pcie)
{
	int err;

	/* Begin initialization */
	pci_write_reg(pcie, 0, PCIETCTLR);

	/* Set mode */
	pci_write_reg(pcie, 1, PCIEMSR);

	/*
	 * Initial header for port config space is type 1, set the device
	 * class to match. Hardware takes care of propagating the IDSETR
	 * settings, so there is no need to bother with a quirk.
	 */
	pci_write_reg(pcie, PCI_CLASS_BRIDGE_PCI << 16, IDSETR1);

	/*
	 * Setup Secondary Bus Number & Subordinate Bus Number, even though
	 * they aren't used, to avoid bridge being detected as broken.
	 */
	rcar_rmw32(pcie, RCONF(PCI_SECONDARY_BUS), 0xff, 1);
	rcar_rmw32(pcie, RCONF(PCI_SUBORDINATE_BUS), 0xff, 1);

	/* Initialize default capabilities. */
	rcar_rmw32(pcie, REXPCAP(0), 0, PCI_CAP_ID_EXP);
	rcar_rmw32(pcie, REXPCAP(PCI_EXP_FLAGS),
		PCI_EXP_FLAGS_TYPE, PCI_EXP_TYPE_ROOT_PORT << 4);
	rcar_rmw32(pcie, RCONF(PCI_HEADER_TYPE), 0x7f,
		PCI_HEADER_TYPE_BRIDGE);

	/* Enable data link layer active state reporting */
	rcar_rmw32(pcie, REXPCAP(PCI_EXP_LNKCAP), 0, PCI_EXP_LNKCAP_DLLLARC);

	/* Write out the physical slot number = 0 */
	rcar_rmw32(pcie, REXPCAP(PCI_EXP_SLTCAP), PCI_EXP_SLTCAP_PSN, 0);

	/* Set the completion timer timeout to the maximum 50ms. */
	rcar_rmw32(pcie, TLCTLR+1, 0x3f, 50);

	/* Terminate list of capabilities (Next Capability Offset=0) */
	rcar_rmw32(pcie, RVCCAP(0), 0xfff0, 0);

	/* Enable MAC data scrambling. */
	rcar_rmw32(pcie, MACCTLR, SCRAMBLE_DISABLE, 0);

	/* Finish initialization - establish a PCI Express link */
	pci_write_reg(pcie, CFINIT, PCIETCTLR);

	/* This will timeout if we don't have a link. */
	err = rcar_pcie_wait_for_dl(pcie);
	if (err)
		return err;

	/* Enable INTx interrupts */
	rcar_rmw32(pcie, PCIEINTXR, 0, 0xF << 8);

	/* Enable slave Bus Mastering */
	rcar_rmw32(pcie, RCONF(PCI_STATUS), PCI_STATUS_DEVSEL_MASK,
		PCI_COMMAND_IO | PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER |
		PCI_STATUS_CAP_LIST | PCI_STATUS_DEVSEL_FAST);

	wmb();

	return 0;
}

static int rcar_pcie_hw_init_h1(struct rcar_pcie *pcie)
{
	unsigned int timeout = 10;

	/* Initialize the phy */
	phy_write_reg(pcie, 0, 0x42, 0x1, 0x0EC34191);
	phy_write_reg(pcie, 1, 0x42, 0x1, 0x0EC34180);
	phy_write_reg(pcie, 0, 0x43, 0x1, 0x00210188);
	phy_write_reg(pcie, 1, 0x43, 0x1, 0x00210188);
	phy_write_reg(pcie, 0, 0x44, 0x1, 0x015C0014);
	phy_write_reg(pcie, 1, 0x44, 0x1, 0x015C0014);
	phy_write_reg(pcie, 1, 0x4C, 0x1, 0x786174A0);
	phy_write_reg(pcie, 1, 0x4D, 0x1, 0x048000BB);
	phy_write_reg(pcie, 0, 0x51, 0x1, 0x079EC062);
	phy_write_reg(pcie, 0, 0x52, 0x1, 0x20000000);
	phy_write_reg(pcie, 1, 0x52, 0x1, 0x20000000);
	phy_write_reg(pcie, 1, 0x56, 0x1, 0x00003806);

	phy_write_reg(pcie, 0, 0x60, 0x1, 0x004B03A5);
	phy_write_reg(pcie, 0, 0x64, 0x1, 0x3F0F1F0F);
	phy_write_reg(pcie, 0, 0x66, 0x1, 0x00008000);

	while (timeout--) {
		if (pci_read_reg(pcie, H1_PCIEPHYSR))
			return rcar_pcie_hw_init(pcie);

		msleep(5);
	}

	return -ETIMEDOUT;
}

static int rcar_pcie_get_resources(struct platform_device *pdev,
				   struct rcar_pcie *pcie)
{
	struct resource res;
	int err;

	err = of_address_to_resource(pdev->dev.of_node, 0, &res);
	if (err)
		return err;

	pcie->clk = devm_clk_get(&pdev->dev, "pcie");
	if (IS_ERR(pcie->clk)) {
		dev_err(pcie->dev, "cannot get platform clock\n");
		return PTR_ERR(pcie->clk);
	}
	err = clk_prepare_enable(pcie->clk);
	if (err)
		goto fail_clk;

	pcie->bus_clk = devm_clk_get(&pdev->dev, "pcie_bus");
	if (IS_ERR(pcie->bus_clk)) {
		dev_err(pcie->dev, "cannot get pcie bus clock\n");
		err = PTR_ERR(pcie->bus_clk);
		goto fail_clk;
	}
	err = clk_prepare_enable(pcie->bus_clk);
	if (err)
		goto err_map_reg;

	pcie->base = devm_ioremap_resource(&pdev->dev, &res);
	if (IS_ERR(pcie->base)) {
		err = PTR_ERR(pcie->base);
		goto err_map_reg;
	}

	return 0;

err_map_reg:
	clk_disable_unprepare(pcie->bus_clk);
fail_clk:
	clk_disable_unprepare(pcie->clk);

	return err;
}

static int rcar_pcie_inbound_ranges(struct rcar_pcie *pcie,
				    struct of_pci_range *range,
				    int *index)
{
	u64 restype = range->flags;
	u64 cpu_addr = range->cpu_addr;
	u64 cpu_end = range->cpu_addr + range->size;
	u64 pci_addr = range->pci_addr;
	u32 flags = LAM_64BIT | LAR_ENABLE;
	u64 mask;
	u64 size;
	int idx = *index;

	if (restype & IORESOURCE_PREFETCH)
		flags |= LAM_PREFETCH;

	/*
	 * If the size of the range is larger than the alignment of the start
	 * address, we have to use multiple entries to perform the mapping.
	 */
	if (cpu_addr > 0) {
		unsigned long nr_zeros = __ffs64(cpu_addr);
		u64 alignment = 1ULL << nr_zeros;
		size = min(range->size, alignment);
	} else {
		size = range->size;
	}
	/* Hardware supports max 4GiB inbound region */
	size = min(size, 1ULL << 32);

	mask = roundup_pow_of_two(size) - 1;
	mask &= ~0xf;

	while (cpu_addr < cpu_end) {
		/*
		 * Set up 64-bit inbound regions as the range parser doesn't
		 * distinguish between 32 and 64-bit types.
		 */
		pci_write_reg(pcie, lower_32_bits(pci_addr), PCIEPRAR(idx));
		pci_write_reg(pcie, lower_32_bits(cpu_addr), PCIELAR(idx));
		pci_write_reg(pcie, lower_32_bits(mask) | flags, PCIELAMR(idx));

		pci_write_reg(pcie, upper_32_bits(pci_addr), PCIEPRAR(idx+1));
		pci_write_reg(pcie, upper_32_bits(cpu_addr), PCIELAR(idx+1));
		pci_write_reg(pcie, 0, PCIELAMR(idx+1));

		pci_addr += size;
		cpu_addr += size;
		idx += 2;

		if (idx > MAX_NR_INBOUND_MAPS) {
			dev_err(pcie->dev, "Failed to map inbound regions!\n");
			return -EINVAL;
		}
	}
	*index = idx;

	return 0;
}

static int pci_dma_range_parser_init(struct of_pci_range_parser *parser,
				     struct device_node *node)
{
	const int na = 3, ns = 2;
	int rlen;

	parser->node = node;
	parser->pna = of_n_addr_cells(node);
	parser->np = parser->pna + na + ns;

	parser->range = of_get_property(node, "dma-ranges", &rlen);
	if (!parser->range)
		return -ENOENT;

	parser->end = parser->range + rlen / sizeof(__be32);
	return 0;
}

static int rcar_pcie_parse_map_dma_ranges(struct rcar_pcie *pcie,
					  struct device_node *np)
{
	struct of_pci_range range;
	struct of_pci_range_parser parser;
	int index = 0;
	int err;

	if (pci_dma_range_parser_init(&parser, np))
		return -EINVAL;

	/* Get the dma-ranges from DT */
	for_each_of_pci_range(&parser, &range) {
		u64 end = range.cpu_addr + range.size - 1;
		dev_dbg(pcie->dev, "0x%08x 0x%016llx..0x%016llx -> 0x%016llx\n",
			range.flags, range.cpu_addr, end, range.pci_addr);

		err = rcar_pcie_inbound_ranges(pcie, &range, &index);
		if (err)
			return err;
	}

	return 0;
}

static const struct of_device_id rcar_pcie_of_match[] = {
	{ .compatible = "renesas,pcie-r8a7779", .data = rcar_pcie_hw_init_h1 },
	{ .compatible = "renesas,pcie-r8a7790", .data = rcar_pcie_hw_init },
	{ .compatible = "renesas,pcie-r8a7791", .data = rcar_pcie_hw_init },
	{},
};
MODULE_DEVICE_TABLE(of, rcar_pcie_of_match);

static int rcar_pcie_probe(struct platform_device *pdev)
{
	struct rcar_pcie *pcie;
	unsigned int data;
	struct of_pci_range range;
	struct of_pci_range_parser parser;
	const struct of_device_id *of_id;
	int err, win = 0;
	int (*hw_init_fn)(struct rcar_pcie *);

	pcie = devm_kzalloc(&pdev->dev, sizeof(*pcie), GFP_KERNEL);
	if (!pcie)
		return -ENOMEM;

	pcie->dev = &pdev->dev;
	platform_set_drvdata(pdev, pcie);

	/* Get the bus range */
	if (of_pci_parse_bus_range(pdev->dev.of_node, &pcie->busn)) {
		dev_err(&pdev->dev, "failed to parse bus-range property\n");
		return -EINVAL;
	}

	if (of_pci_range_parser_init(&parser, pdev->dev.of_node)) {
		dev_err(&pdev->dev, "missing ranges property\n");
		return -EINVAL;
	}

	err = rcar_pcie_get_resources(pdev, pcie);
	if (err < 0) {
		dev_err(&pdev->dev, "failed to request resources: %d\n", err);
		return err;
	}

	for_each_of_pci_range(&parser, &range) {
		of_pci_range_to_resource(&range, pdev->dev.of_node,
						&pcie->res[win++]);

		if (win > PCI_MAX_RESOURCES)
			break;
	}

	 err = rcar_pcie_parse_map_dma_ranges(pcie, pdev->dev.of_node);
	 if (err)
		return err;

	of_id = of_match_device(rcar_pcie_of_match, pcie->dev);
	if (!of_id || !of_id->data)
		return -EINVAL;
	hw_init_fn = of_id->data;

	/* Failure to get a link might just be that no cards are inserted */
	err = hw_init_fn(pcie);
	if (err) {
		dev_info(&pdev->dev, "PCIe link down\n");
		return 0;
	}

	data = pci_read_reg(pcie, MACSR);
	dev_info(&pdev->dev, "PCIe x%d: link up\n", (data >> 20) & 0x3f);

	rcar_pcie_enable(pcie);

	return 0;
}

static struct platform_driver rcar_pcie_driver = {
	.driver = {
		.name = DRV_NAME,
		.owner = THIS_MODULE,
		.of_match_table = rcar_pcie_of_match,
		.suppress_bind_attrs = true,
	},
	.probe = rcar_pcie_probe,
};
module_platform_driver(rcar_pcie_driver);

MODULE_AUTHOR("Phil Edworthy <phil.edworthy@renesas.com>");
MODULE_DESCRIPTION("Renesas R-Car PCIe driver");
MODULE_LICENSE("GPLv2");