linux-vybrid_public/drivers/pci/host/pci-tegra.c

/*
 * PCIe host controller driver for Tegra SoCs
 *
 * Copyright (c) 2010, CompuLab, Ltd.
 * Author: Mike Rapoport <mike@compulab.co.il>
 *
 * Based on NVIDIA PCIe driver
 * Copyright (c) 2008-2009, NVIDIA Corporation.
 *
 * Bits taken from arch/arm/mach-dove/pcie.c
 *
 * 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.
 *
 * This program is distributed in the hope that 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, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <linux/clk.h>
#include <linux/clk/tegra.h>
#include <linux/delay.h>
#include <linux/export.h>
#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/pci.h>
#include <linux/platform_device.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/tegra-cpuidle.h>
#include <linux/tegra-powergate.h>
#include <linux/vmalloc.h>
#include <linux/regulator/consumer.h>

#include <asm/mach/irq.h>
#include <asm/mach/map.h>
#include <asm/mach/pci.h>

#define INT_PCI_MSI_NR (8 * 32)

/* register definitions */

#define AFI_AXI_BAR0_SZ	0x00
#define AFI_AXI_BAR1_SZ	0x04
#define AFI_AXI_BAR2_SZ	0x08
#define AFI_AXI_BAR3_SZ	0x0c
#define AFI_AXI_BAR4_SZ	0x10
#define AFI_AXI_BAR5_SZ	0x14

#define AFI_AXI_BAR0_START	0x18
#define AFI_AXI_BAR1_START	0x1c
#define AFI_AXI_BAR2_START	0x20
#define AFI_AXI_BAR3_START	0x24
#define AFI_AXI_BAR4_START	0x28
#define AFI_AXI_BAR5_START	0x2c

#define AFI_FPCI_BAR0	0x30
#define AFI_FPCI_BAR1	0x34
#define AFI_FPCI_BAR2	0x38
#define AFI_FPCI_BAR3	0x3c
#define AFI_FPCI_BAR4	0x40
#define AFI_FPCI_BAR5	0x44

#define AFI_CACHE_BAR0_SZ	0x48
#define AFI_CACHE_BAR0_ST	0x4c
#define AFI_CACHE_BAR1_SZ	0x50
#define AFI_CACHE_BAR1_ST	0x54

#define AFI_MSI_BAR_SZ		0x60
#define AFI_MSI_FPCI_BAR_ST	0x64
#define AFI_MSI_AXI_BAR_ST	0x68

#define AFI_MSI_VEC0		0x6c
#define AFI_MSI_VEC1		0x70
#define AFI_MSI_VEC2		0x74
#define AFI_MSI_VEC3		0x78
#define AFI_MSI_VEC4		0x7c
#define AFI_MSI_VEC5		0x80
#define AFI_MSI_VEC6		0x84
#define AFI_MSI_VEC7		0x88

#define AFI_MSI_EN_VEC0		0x8c
#define AFI_MSI_EN_VEC1		0x90
#define AFI_MSI_EN_VEC2		0x94
#define AFI_MSI_EN_VEC3		0x98
#define AFI_MSI_EN_VEC4		0x9c
#define AFI_MSI_EN_VEC5		0xa0
#define AFI_MSI_EN_VEC6		0xa4
#define AFI_MSI_EN_VEC7		0xa8

#define AFI_CONFIGURATION		0xac
#define  AFI_CONFIGURATION_EN_FPCI	(1 << 0)

#define AFI_FPCI_ERROR_MASKS	0xb0

#define AFI_INTR_MASK		0xb4
#define  AFI_INTR_MASK_INT_MASK	(1 << 0)
#define  AFI_INTR_MASK_MSI_MASK	(1 << 8)

#define AFI_INTR_CODE			0xb8
#define  AFI_INTR_CODE_MASK		0xf
#define  AFI_INTR_AXI_SLAVE_ERROR	1
#define  AFI_INTR_AXI_DECODE_ERROR	2
#define  AFI_INTR_TARGET_ABORT		3
#define  AFI_INTR_MASTER_ABORT		4
#define  AFI_INTR_INVALID_WRITE		5
#define  AFI_INTR_LEGACY		6
#define  AFI_INTR_FPCI_DECODE_ERROR	7

#define AFI_INTR_SIGNATURE	0xbc
#define AFI_UPPER_FPCI_ADDRESS	0xc0
#define AFI_SM_INTR_ENABLE	0xc4
#define  AFI_SM_INTR_INTA_ASSERT	(1 << 0)
#define  AFI_SM_INTR_INTB_ASSERT	(1 << 1)
#define  AFI_SM_INTR_INTC_ASSERT	(1 << 2)
#define  AFI_SM_INTR_INTD_ASSERT	(1 << 3)
#define  AFI_SM_INTR_INTA_DEASSERT	(1 << 4)
#define  AFI_SM_INTR_INTB_DEASSERT	(1 << 5)
#define  AFI_SM_INTR_INTC_DEASSERT	(1 << 6)
#define  AFI_SM_INTR_INTD_DEASSERT	(1 << 7)

#define AFI_AFI_INTR_ENABLE		0xc8
#define  AFI_INTR_EN_INI_SLVERR		(1 << 0)
#define  AFI_INTR_EN_INI_DECERR		(1 << 1)
#define  AFI_INTR_EN_TGT_SLVERR		(1 << 2)
#define  AFI_INTR_EN_TGT_DECERR		(1 << 3)
#define  AFI_INTR_EN_TGT_WRERR		(1 << 4)
#define  AFI_INTR_EN_DFPCI_DECERR	(1 << 5)
#define  AFI_INTR_EN_AXI_DECERR		(1 << 6)
#define  AFI_INTR_EN_FPCI_TIMEOUT	(1 << 7)
#define  AFI_INTR_EN_PRSNT_SENSE	(1 << 8)

#define AFI_PCIE_CONFIG					0x0f8
#define  AFI_PCIE_CONFIG_PCIE_DISABLE(x)		(1 << ((x) + 1))
#define  AFI_PCIE_CONFIG_PCIE_DISABLE_ALL		0xe
#define  AFI_PCIE_CONFIG_SM2TMS0_XBAR_CONFIG_MASK	(0xf << 20)
#define  AFI_PCIE_CONFIG_SM2TMS0_XBAR_CONFIG_SINGLE	(0x0 << 20)
#define  AFI_PCIE_CONFIG_SM2TMS0_XBAR_CONFIG_420	(0x0 << 20)
#define  AFI_PCIE_CONFIG_SM2TMS0_XBAR_CONFIG_DUAL	(0x1 << 20)
#define  AFI_PCIE_CONFIG_SM2TMS0_XBAR_CONFIG_222	(0x1 << 20)
#define  AFI_PCIE_CONFIG_SM2TMS0_XBAR_CONFIG_411	(0x2 << 20)

#define AFI_FUSE			0x104
#define  AFI_FUSE_PCIE_T0_GEN2_DIS	(1 << 2)

#define AFI_PEX0_CTRL			0x110
#define AFI_PEX1_CTRL			0x118
#define AFI_PEX2_CTRL			0x128
#define  AFI_PEX_CTRL_RST		(1 << 0)
#define  AFI_PEX_CTRL_CLKREQ_EN		(1 << 1)
#define  AFI_PEX_CTRL_REFCLK_EN		(1 << 3)

#define AFI_PEXBIAS_CTRL_0		0x168

#define RP_VEND_XP	0x00000F00
#define  RP_VEND_XP_DL_UP	(1 << 30)

#define RP_LINK_CONTROL_STATUS			0x00000090
#define  RP_LINK_CONTROL_STATUS_DL_LINK_ACTIVE	0x20000000
#define  RP_LINK_CONTROL_STATUS_LINKSTAT_MASK	0x3fff0000

#define PADS_CTL_SEL		0x0000009C

#define PADS_CTL		0x000000A0
#define  PADS_CTL_IDDQ_1L	(1 << 0)
#define  PADS_CTL_TX_DATA_EN_1L	(1 << 6)
#define  PADS_CTL_RX_DATA_EN_1L	(1 << 10)

#define PADS_PLL_CTL_TEGRA20			0x000000B8
#define PADS_PLL_CTL_TEGRA30			0x000000B4
#define  PADS_PLL_CTL_RST_B4SM			(1 << 1)
#define  PADS_PLL_CTL_LOCKDET			(1 << 8)
#define  PADS_PLL_CTL_REFCLK_MASK		(0x3 << 16)
#define  PADS_PLL_CTL_REFCLK_INTERNAL_CML	(0 << 16)
#define  PADS_PLL_CTL_REFCLK_INTERNAL_CMOS	(1 << 16)
#define  PADS_PLL_CTL_REFCLK_EXTERNAL		(2 << 16)
#define  PADS_PLL_CTL_TXCLKREF_MASK		(0x1 << 20)
#define  PADS_PLL_CTL_TXCLKREF_DIV10		(0 << 20)
#define  PADS_PLL_CTL_TXCLKREF_DIV5		(1 << 20)
#define  PADS_PLL_CTL_TXCLKREF_BUF_EN		(1 << 22)

#define PADS_REFCLK_CFG0			0x000000C8
#define PADS_REFCLK_CFG1			0x000000CC

/*
 * Fields in PADS_REFCLK_CFG*. Those registers form an array of 16-bit
 * entries, one entry per PCIe port. These field definitions and desired
 * values aren't in the TRM, but do come from NVIDIA.
 */
#define PADS_REFCLK_CFG_TERM_SHIFT		2  /* 6:2 */
#define PADS_REFCLK_CFG_E_TERM_SHIFT		7
#define PADS_REFCLK_CFG_PREDI_SHIFT		8  /* 11:8 */
#define PADS_REFCLK_CFG_DRVI_SHIFT		12 /* 15:12 */

/* Default value provided by HW engineering is 0xfa5c */
#define PADS_REFCLK_CFG_VALUE \
	( \
		(0x17 << PADS_REFCLK_CFG_TERM_SHIFT)   | \
		(0    << PADS_REFCLK_CFG_E_TERM_SHIFT) | \
		(0xa  << PADS_REFCLK_CFG_PREDI_SHIFT)  | \
		(0xf  << PADS_REFCLK_CFG_DRVI_SHIFT)     \
	)

struct tegra_msi {
	struct msi_chip chip;
	DECLARE_BITMAP(used, INT_PCI_MSI_NR);
	struct irq_domain *domain;
	unsigned long pages;
	struct mutex lock;
	int irq;
};

/* used to differentiate between Tegra SoC generations */
struct tegra_pcie_soc_data {
	unsigned int num_ports;
	unsigned int msi_base_shift;
	u32 pads_pll_ctl;
	u32 tx_ref_sel;
	bool has_pex_clkreq_en;
	bool has_pex_bias_ctrl;
	bool has_intr_prsnt_sense;
	bool has_avdd_supply;
	bool has_cml_clk;
};

static inline struct tegra_msi *to_tegra_msi(struct msi_chip *chip)
{
	return container_of(chip, struct tegra_msi, chip);
}

struct tegra_pcie {
	struct device *dev;

	void __iomem *pads;
	void __iomem *afi;
	int irq;

	struct list_head busses;
	struct resource *cs;

	struct resource io;
	struct resource mem;
	struct resource prefetch;
	struct resource busn;

	struct clk *pex_clk;
	struct clk *afi_clk;
	struct clk *pcie_xclk;
	struct clk *pll_e;
	struct clk *cml_clk;

	struct tegra_msi msi;

	struct list_head ports;
	unsigned int num_ports;
	u32 xbar_config;

	struct regulator *pex_clk_supply;
	struct regulator *vdd_supply;
	struct regulator *avdd_supply;

	const struct tegra_pcie_soc_data *soc_data;
};

struct tegra_pcie_port {
	struct tegra_pcie *pcie;
	struct list_head list;
	struct resource regs;
	void __iomem *base;
	unsigned int index;
	unsigned int lanes;
};

struct tegra_pcie_bus {
	struct vm_struct *area;
	struct list_head list;
	unsigned int nr;
};

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

static inline void afi_writel(struct tegra_pcie *pcie, u32 value,
			      unsigned long offset)
{
	writel(value, pcie->afi + offset);
}

static inline u32 afi_readl(struct tegra_pcie *pcie, unsigned long offset)
{
	return readl(pcie->afi + offset);
}

static inline void pads_writel(struct tegra_pcie *pcie, u32 value,
			       unsigned long offset)
{
	writel(value, pcie->pads + offset);
}

static inline u32 pads_readl(struct tegra_pcie *pcie, unsigned long offset)
{
	return readl(pcie->pads + offset);
}

/*
 * The configuration space mapping on Tegra is somewhat similar to the ECAM
 * defined by PCIe. However it deviates a bit in how the 4 bits for extended
 * register accesses are mapped:
 *
 *    [27:24] extended register number
 *    [23:16] bus number
 *    [15:11] device number
 *    [10: 8] function number
 *    [ 7: 0] register number
 *
 * Mapping the whole extended configuration space would require 256 MiB of
 * virtual address space, only a small part of which will actually be used.
 * To work around this, a 1 MiB of virtual addresses are allocated per bus
 * when the bus is first accessed. When the physical range is mapped, the
 * the bus number bits are hidden so that the extended register number bits
 * appear as bits [19:16]. Therefore the virtual mapping looks like this:
 *
 *    [19:16] extended register number
 *    [15:11] device number
 *    [10: 8] function number
 *    [ 7: 0] register number
 *
 * This is achieved by stitching together 16 chunks of 64 KiB of physical
 * address space via the MMU.
 */
static unsigned long tegra_pcie_conf_offset(unsigned int devfn, int where)
{
	return ((where & 0xf00) << 8) | (PCI_SLOT(devfn) << 11) |
	       (PCI_FUNC(devfn) << 8) | (where & 0xfc);
}

static struct tegra_pcie_bus *tegra_pcie_bus_alloc(struct tegra_pcie *pcie,
						   unsigned int busnr)
{
	pgprot_t prot = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY | L_PTE_XN |
			L_PTE_MT_DEV_SHARED | L_PTE_SHARED;
	phys_addr_t cs = pcie->cs->start;
	struct tegra_pcie_bus *bus;
	unsigned int i;
	int err;

	bus = kzalloc(sizeof(*bus), GFP_KERNEL);
	if (!bus)
		return ERR_PTR(-ENOMEM);

	INIT_LIST_HEAD(&bus->list);
	bus->nr = busnr;

	/* allocate 1 MiB of virtual addresses */
	bus->area = get_vm_area(SZ_1M, VM_IOREMAP);
	if (!bus->area) {
		err = -ENOMEM;
		goto free;
	}

	/* map each of the 16 chunks of 64 KiB each */
	for (i = 0; i < 16; i++) {
		unsigned long virt = (unsigned long)bus->area->addr +
				     i * SZ_64K;
		phys_addr_t phys = cs + i * SZ_1M + busnr * SZ_64K;

		err = ioremap_page_range(virt, virt + SZ_64K, phys, prot);
		if (err < 0) {
			dev_err(pcie->dev, "ioremap_page_range() failed: %d\n",
				err);
			goto unmap;
		}
	}

	return bus;

unmap:
	vunmap(bus->area->addr);
free:
	kfree(bus);
	return ERR_PTR(err);
}

/*
 * Look up a virtual address mapping for the specified bus number. If no such
 * mapping existis, try to create one.
 */
static void __iomem *tegra_pcie_bus_map(struct tegra_pcie *pcie,
					unsigned int busnr)
{
	struct tegra_pcie_bus *bus;

	list_for_each_entry(bus, &pcie->busses, list)
		if (bus->nr == busnr)
			return bus->area->addr;

	bus = tegra_pcie_bus_alloc(pcie, busnr);
	if (IS_ERR(bus))
		return NULL;

	list_add_tail(&bus->list, &pcie->busses);

	return bus->area->addr;
}

static void __iomem *tegra_pcie_conf_address(struct pci_bus *bus,
					     unsigned int devfn,
					     int where)
{
	struct tegra_pcie *pcie = sys_to_pcie(bus->sysdata);
	void __iomem *addr = NULL;

	if (bus->number == 0) {
		unsigned int slot = PCI_SLOT(devfn);
		struct tegra_pcie_port *port;

		list_for_each_entry(port, &pcie->ports, list) {
			if (port->index + 1 == slot) {
				addr = port->base + (where & ~3);
				break;
			}
		}
	} else {
		addr = tegra_pcie_bus_map(pcie, bus->number);
		if (!addr) {
			dev_err(pcie->dev,
				"failed to map cfg. space for bus %u\n",
				bus->number);
			return NULL;
		}

		addr += tegra_pcie_conf_offset(devfn, where);
	}

	return addr;
}

static int tegra_pcie_read_conf(struct pci_bus *bus, unsigned int devfn,
				int where, int size, u32 *value)
{
	void __iomem *addr;

	addr = tegra_pcie_conf_address(bus, devfn, where);
	if (!addr) {
		*value = 0xffffffff;
		return PCIBIOS_DEVICE_NOT_FOUND;
	}

	*value = readl(addr);

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

	return PCIBIOS_SUCCESSFUL;
}

static int tegra_pcie_write_conf(struct pci_bus *bus, unsigned int devfn,
				 int where, int size, u32 value)
{
	void __iomem *addr;
	u32 mask, tmp;

	addr = tegra_pcie_conf_address(bus, devfn, where);
	if (!addr)
		return PCIBIOS_DEVICE_NOT_FOUND;

	if (size == 4) {
		writel(value, addr);
		return PCIBIOS_SUCCESSFUL;
	}

	if (size == 2)
		mask = ~(0xffff << ((where & 0x3) * 8));
	else if (size == 1)
		mask = ~(0xff << ((where & 0x3) * 8));
	else
		return PCIBIOS_BAD_REGISTER_NUMBER;

	tmp = readl(addr) & mask;
	tmp |= value << ((where & 0x3) * 8);
	writel(tmp, addr);

	return PCIBIOS_SUCCESSFUL;
}

static struct pci_ops tegra_pcie_ops = {
	.read = tegra_pcie_read_conf,
	.write = tegra_pcie_write_conf,
};

static unsigned long tegra_pcie_port_get_pex_ctrl(struct tegra_pcie_port *port)
{
	unsigned long ret = 0;

	switch (port->index) {
	case 0:
		ret = AFI_PEX0_CTRL;
		break;

	case 1:
		ret = AFI_PEX1_CTRL;
		break;

	case 2:
		ret = AFI_PEX2_CTRL;
		break;
	}

	return ret;
}

static void tegra_pcie_port_reset(struct tegra_pcie_port *port)
{
	unsigned long ctrl = tegra_pcie_port_get_pex_ctrl(port);
	unsigned long value;

	/* pulse reset signal */
	value = afi_readl(port->pcie, ctrl);
	value &= ~AFI_PEX_CTRL_RST;
	afi_writel(port->pcie, value, ctrl);

	usleep_range(1000, 2000);

	value = afi_readl(port->pcie, ctrl);
	value |= AFI_PEX_CTRL_RST;
	afi_writel(port->pcie, value, ctrl);
}

static void tegra_pcie_port_enable(struct tegra_pcie_port *port)
{
	const struct tegra_pcie_soc_data *soc = port->pcie->soc_data;
	unsigned long ctrl = tegra_pcie_port_get_pex_ctrl(port);
	unsigned long value;

	/* enable reference clock */
	value = afi_readl(port->pcie, ctrl);
	value |= AFI_PEX_CTRL_REFCLK_EN;

	if (soc->has_pex_clkreq_en)
		value |= AFI_PEX_CTRL_CLKREQ_EN;

	afi_writel(port->pcie, value, ctrl);

	tegra_pcie_port_reset(port);
}

static void tegra_pcie_port_disable(struct tegra_pcie_port *port)
{
	unsigned long ctrl = tegra_pcie_port_get_pex_ctrl(port);
	unsigned long value;

	/* assert port reset */
	value = afi_readl(port->pcie, ctrl);
	value &= ~AFI_PEX_CTRL_RST;
	afi_writel(port->pcie, value, ctrl);

	/* disable reference clock */
	value = afi_readl(port->pcie, ctrl);
	value &= ~AFI_PEX_CTRL_REFCLK_EN;
	afi_writel(port->pcie, value, ctrl);
}

static void tegra_pcie_port_free(struct tegra_pcie_port *port)
{
	struct tegra_pcie *pcie = port->pcie;

	devm_iounmap(pcie->dev, port->base);
	devm_release_mem_region(pcie->dev, port->regs.start,
				resource_size(&port->regs));
	list_del(&port->list);
	devm_kfree(pcie->dev, port);
}

static void tegra_pcie_fixup_bridge(struct pci_dev *dev)
{
	u16 reg;

	if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE) {
		pci_read_config_word(dev, PCI_COMMAND, &reg);
		reg |= (PCI_COMMAND_IO | PCI_COMMAND_MEMORY |
			PCI_COMMAND_MASTER | PCI_COMMAND_SERR);
		pci_write_config_word(dev, PCI_COMMAND, reg);
	}
}
DECLARE_PCI_FIXUP_FINAL(PCI_ANY_ID, PCI_ANY_ID, tegra_pcie_fixup_bridge);

/* Tegra PCIE root complex wrongly reports device class */
static void tegra_pcie_fixup_class(struct pci_dev *dev)
{
	dev->class = PCI_CLASS_BRIDGE_PCI << 8;
}
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0bf0, tegra_pcie_fixup_class);
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0bf1, tegra_pcie_fixup_class);
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0e1c, tegra_pcie_fixup_class);
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0e1d, tegra_pcie_fixup_class);

/* Tegra PCIE requires relaxed ordering */
static void tegra_pcie_relax_enable(struct pci_dev *dev)
{
	pcie_capability_set_word(dev, PCI_EXP_DEVCTL, PCI_EXP_DEVCTL_RELAX_EN);
}
DECLARE_PCI_FIXUP_FINAL(PCI_ANY_ID, PCI_ANY_ID, tegra_pcie_relax_enable);

static int tegra_pcie_setup(int nr, struct pci_sys_data *sys)
{
	struct tegra_pcie *pcie = sys_to_pcie(sys);

	pci_add_resource_offset(&sys->resources, &pcie->mem, sys->mem_offset);
	pci_add_resource_offset(&sys->resources, &pcie->prefetch,
				sys->mem_offset);
	pci_add_resource(&sys->resources, &pcie->busn);

	pci_ioremap_io(nr * SZ_64K, pcie->io.start);

	return 1;
}

static int tegra_pcie_map_irq(const struct pci_dev *pdev, u8 slot, u8 pin)
{
	struct tegra_pcie *pcie = sys_to_pcie(pdev->bus->sysdata);

	tegra_cpuidle_pcie_irqs_in_use();

	return pcie->irq;
}

static void tegra_pcie_add_bus(struct pci_bus *bus)
{
	if (IS_ENABLED(CONFIG_PCI_MSI)) {
		struct tegra_pcie *pcie = sys_to_pcie(bus->sysdata);

		bus->msi = &pcie->msi.chip;
	}
}

static struct pci_bus *tegra_pcie_scan_bus(int nr, struct pci_sys_data *sys)
{
	struct tegra_pcie *pcie = sys_to_pcie(sys);
	struct pci_bus *bus;

	bus = pci_create_root_bus(pcie->dev, sys->busnr, &tegra_pcie_ops, sys,
				  &sys->resources);
	if (!bus)
		return NULL;

	pci_scan_child_bus(bus);

	return bus;
}

static irqreturn_t tegra_pcie_isr(int irq, void *arg)
{
	const char *err_msg[] = {
		"Unknown",
		"AXI slave error",
		"AXI decode error",
		"Target abort",
		"Master abort",
		"Invalid write",
		"Response decoding error",
		"AXI response decoding error",
		"Transaction timeout",
	};
	struct tegra_pcie *pcie = arg;
	u32 code, signature;

	code = afi_readl(pcie, AFI_INTR_CODE) & AFI_INTR_CODE_MASK;
	signature = afi_readl(pcie, AFI_INTR_SIGNATURE);
	afi_writel(pcie, 0, AFI_INTR_CODE);

	if (code == AFI_INTR_LEGACY)
		return IRQ_NONE;

	if (code >= ARRAY_SIZE(err_msg))
		code = 0;

	/*
	 * do not pollute kernel log with master abort reports since they
	 * happen a lot during enumeration
	 */
	if (code == AFI_INTR_MASTER_ABORT)
		dev_dbg(pcie->dev, "%s, signature: %08x\n", err_msg[code],
			signature);
	else
		dev_err(pcie->dev, "%s, signature: %08x\n", err_msg[code],
			signature);

	if (code == AFI_INTR_TARGET_ABORT || code == AFI_INTR_MASTER_ABORT ||
	    code == AFI_INTR_FPCI_DECODE_ERROR) {
		u32 fpci = afi_readl(pcie, AFI_UPPER_FPCI_ADDRESS) & 0xff;
		u64 address = (u64)fpci << 32 | (signature & 0xfffffffc);

		if (code == AFI_INTR_MASTER_ABORT)
			dev_dbg(pcie->dev, "  FPCI address: %10llx\n", address);
		else
			dev_err(pcie->dev, "  FPCI address: %10llx\n", address);
	}

	return IRQ_HANDLED;
}

/*
 * FPCI map is as follows:
 * - 0xfdfc000000: I/O space
 * - 0xfdfe000000: type 0 configuration space
 * - 0xfdff000000: type 1 configuration space
 * - 0xfe00000000: type 0 extended configuration space
 * - 0xfe10000000: type 1 extended configuration space
 */
static void tegra_pcie_setup_translations(struct tegra_pcie *pcie)
{
	u32 fpci_bar, size, axi_address;

	/* Bar 0: type 1 extended configuration space */
	fpci_bar = 0xfe100000;
	size = resource_size(pcie->cs);
	axi_address = pcie->cs->start;
	afi_writel(pcie, axi_address, AFI_AXI_BAR0_START);
	afi_writel(pcie, size >> 12, AFI_AXI_BAR0_SZ);
	afi_writel(pcie, fpci_bar, AFI_FPCI_BAR0);

	/* Bar 1: downstream IO bar */
	fpci_bar = 0xfdfc0000;
	size = resource_size(&pcie->io);
	axi_address = pcie->io.start;
	afi_writel(pcie, axi_address, AFI_AXI_BAR1_START);
	afi_writel(pcie, size >> 12, AFI_AXI_BAR1_SZ);
	afi_writel(pcie, fpci_bar, AFI_FPCI_BAR1);

	/* Bar 2: prefetchable memory BAR */
	fpci_bar = (((pcie->prefetch.start >> 12) & 0x0fffffff) << 4) | 0x1;
	size = resource_size(&pcie->prefetch);
	axi_address = pcie->prefetch.start;
	afi_writel(pcie, axi_address, AFI_AXI_BAR2_START);
	afi_writel(pcie, size >> 12, AFI_AXI_BAR2_SZ);
	afi_writel(pcie, fpci_bar, AFI_FPCI_BAR2);

	/* Bar 3: non prefetchable memory BAR */
	fpci_bar = (((pcie->mem.start >> 12) & 0x0fffffff) << 4) | 0x1;
	size = resource_size(&pcie->mem);
	axi_address = pcie->mem.start;
	afi_writel(pcie, axi_address, AFI_AXI_BAR3_START);
	afi_writel(pcie, size >> 12, AFI_AXI_BAR3_SZ);
	afi_writel(pcie, fpci_bar, AFI_FPCI_BAR3);

	/* NULL out the remaining BARs as they are not used */
	afi_writel(pcie, 0, AFI_AXI_BAR4_START);
	afi_writel(pcie, 0, AFI_AXI_BAR4_SZ);
	afi_writel(pcie, 0, AFI_FPCI_BAR4);

	afi_writel(pcie, 0, AFI_AXI_BAR5_START);
	afi_writel(pcie, 0, AFI_AXI_BAR5_SZ);
	afi_writel(pcie, 0, AFI_FPCI_BAR5);

	/* map all upstream transactions as uncached */
	afi_writel(pcie, PHYS_OFFSET, AFI_CACHE_BAR0_ST);
	afi_writel(pcie, 0, AFI_CACHE_BAR0_SZ);
	afi_writel(pcie, 0, AFI_CACHE_BAR1_ST);
	afi_writel(pcie, 0, AFI_CACHE_BAR1_SZ);

	/* MSI translations are setup only when needed */
	afi_writel(pcie, 0, AFI_MSI_FPCI_BAR_ST);
	afi_writel(pcie, 0, AFI_MSI_BAR_SZ);
	afi_writel(pcie, 0, AFI_MSI_AXI_BAR_ST);
	afi_writel(pcie, 0, AFI_MSI_BAR_SZ);
}

static int tegra_pcie_enable_controller(struct tegra_pcie *pcie)
{
	const struct tegra_pcie_soc_data *soc = pcie->soc_data;
	struct tegra_pcie_port *port;
	unsigned int timeout;
	unsigned long value;

	/* power down PCIe slot clock bias pad */
	if (soc->has_pex_bias_ctrl)
		afi_writel(pcie, 0, AFI_PEXBIAS_CTRL_0);

	/* configure mode and disable all ports */
	value = afi_readl(pcie, AFI_PCIE_CONFIG);
	value &= ~AFI_PCIE_CONFIG_SM2TMS0_XBAR_CONFIG_MASK;
	value |= AFI_PCIE_CONFIG_PCIE_DISABLE_ALL | pcie->xbar_config;

	list_for_each_entry(port, &pcie->ports, list)
		value &= ~AFI_PCIE_CONFIG_PCIE_DISABLE(port->index);

	afi_writel(pcie, value, AFI_PCIE_CONFIG);

	value = afi_readl(pcie, AFI_FUSE);
	value &= ~AFI_FUSE_PCIE_T0_GEN2_DIS;
	afi_writel(pcie, value, AFI_FUSE);

	/* initialze internal PHY, enable up to 16 PCIE lanes */
	pads_writel(pcie, 0x0, PADS_CTL_SEL);

	/* override IDDQ to 1 on all 4 lanes */
	value = pads_readl(pcie, PADS_CTL);
	value |= PADS_CTL_IDDQ_1L;
	pads_writel(pcie, value, PADS_CTL);

	/*
	 * Set up PHY PLL inputs select PLLE output as refclock,
	 * set TX ref sel to div10 (not div5).
	 */
	value = pads_readl(pcie, soc->pads_pll_ctl);
	value &= ~(PADS_PLL_CTL_REFCLK_MASK | PADS_PLL_CTL_TXCLKREF_MASK);
	value |= PADS_PLL_CTL_REFCLK_INTERNAL_CML | soc->tx_ref_sel;
	pads_writel(pcie, value, soc->pads_pll_ctl);

	/* take PLL out of reset  */
	value = pads_readl(pcie, soc->pads_pll_ctl);
	value |= PADS_PLL_CTL_RST_B4SM;
	pads_writel(pcie, value, soc->pads_pll_ctl);

	/* Configure the reference clock driver */
	value = PADS_REFCLK_CFG_VALUE | (PADS_REFCLK_CFG_VALUE << 16);
	pads_writel(pcie, value, PADS_REFCLK_CFG0);
	if (soc->num_ports > 2)
		pads_writel(pcie, PADS_REFCLK_CFG_VALUE, PADS_REFCLK_CFG1);

	/* wait for the PLL to lock */
	timeout = 300;
	do {
		value = pads_readl(pcie, soc->pads_pll_ctl);
		usleep_range(1000, 2000);
		if (--timeout == 0) {
			pr_err("Tegra PCIe error: timeout waiting for PLL\n");
			return -EBUSY;
		}
	} while (!(value & PADS_PLL_CTL_LOCKDET));

	/* turn off IDDQ override */
	value = pads_readl(pcie, PADS_CTL);
	value &= ~PADS_CTL_IDDQ_1L;
	pads_writel(pcie, value, PADS_CTL);

	/* enable TX/RX data */
	value = pads_readl(pcie, PADS_CTL);
	value |= PADS_CTL_TX_DATA_EN_1L | PADS_CTL_RX_DATA_EN_1L;
	pads_writel(pcie, value, PADS_CTL);

	/* take the PCIe interface module out of reset */
	tegra_periph_reset_deassert(pcie->pcie_xclk);

	/* finally enable PCIe */
	value = afi_readl(pcie, AFI_CONFIGURATION);
	value |= AFI_CONFIGURATION_EN_FPCI;
	afi_writel(pcie, value, AFI_CONFIGURATION);

	value = AFI_INTR_EN_INI_SLVERR | AFI_INTR_EN_INI_DECERR |
		AFI_INTR_EN_TGT_SLVERR | AFI_INTR_EN_TGT_DECERR |
		AFI_INTR_EN_TGT_WRERR | AFI_INTR_EN_DFPCI_DECERR;

	if (soc->has_intr_prsnt_sense)
		value |= AFI_INTR_EN_PRSNT_SENSE;

	afi_writel(pcie, value, AFI_AFI_INTR_ENABLE);
	afi_writel(pcie, 0xffffffff, AFI_SM_INTR_ENABLE);

	/* don't enable MSI for now, only when needed */
	afi_writel(pcie, AFI_INTR_MASK_INT_MASK, AFI_INTR_MASK);

	/* disable all exceptions */
	afi_writel(pcie, 0, AFI_FPCI_ERROR_MASKS);

	return 0;
}

static void tegra_pcie_power_off(struct tegra_pcie *pcie)
{
	const struct tegra_pcie_soc_data *soc = pcie->soc_data;
	int err;

	/* TODO: disable and unprepare clocks? */

	tegra_periph_reset_assert(pcie->pcie_xclk);
	tegra_periph_reset_assert(pcie->afi_clk);
	tegra_periph_reset_assert(pcie->pex_clk);

	tegra_powergate_power_off(TEGRA_POWERGATE_PCIE);

	if (soc->has_avdd_supply) {
		err = regulator_disable(pcie->avdd_supply);
		if (err < 0)
			dev_warn(pcie->dev,
				 "failed to disable AVDD regulator: %d\n",
				 err);
	}

	err = regulator_disable(pcie->pex_clk_supply);
	if (err < 0)
		dev_warn(pcie->dev, "failed to disable pex-clk regulator: %d\n",
			 err);

	err = regulator_disable(pcie->vdd_supply);
	if (err < 0)
		dev_warn(pcie->dev, "failed to disable VDD regulator: %d\n",
			 err);
}

static int tegra_pcie_power_on(struct tegra_pcie *pcie)
{
	const struct tegra_pcie_soc_data *soc = pcie->soc_data;
	int err;

	tegra_periph_reset_assert(pcie->pcie_xclk);
	tegra_periph_reset_assert(pcie->afi_clk);
	tegra_periph_reset_assert(pcie->pex_clk);

	tegra_powergate_power_off(TEGRA_POWERGATE_PCIE);

	/* enable regulators */
	err = regulator_enable(pcie->vdd_supply);
	if (err < 0) {
		dev_err(pcie->dev, "failed to enable VDD regulator: %d\n", err);
		return err;
	}

	err = regulator_enable(pcie->pex_clk_supply);
	if (err < 0) {
		dev_err(pcie->dev, "failed to enable pex-clk regulator: %d\n",
			err);
		return err;
	}

	if (soc->has_avdd_supply) {
		err = regulator_enable(pcie->avdd_supply);
		if (err < 0) {
			dev_err(pcie->dev,
				"failed to enable AVDD regulator: %d\n",
				err);
			return err;
		}
	}

	err = tegra_powergate_sequence_power_up(TEGRA_POWERGATE_PCIE,
						pcie->pex_clk);
	if (err) {
		dev_err(pcie->dev, "powerup sequence failed: %d\n", err);
		return err;
	}

	tegra_periph_reset_deassert(pcie->afi_clk);

	err = clk_prepare_enable(pcie->afi_clk);
	if (err < 0) {
		dev_err(pcie->dev, "failed to enable AFI clock: %d\n", err);
		return err;
	}

	if (soc->has_cml_clk) {
		err = clk_prepare_enable(pcie->cml_clk);
		if (err < 0) {
			dev_err(pcie->dev, "failed to enable CML clock: %d\n",
				err);
			return err;
		}
	}

	err = clk_prepare_enable(pcie->pll_e);
	if (err < 0) {
		dev_err(pcie->dev, "failed to enable PLLE clock: %d\n", err);
		return err;
	}

	return 0;
}

static int tegra_pcie_clocks_get(struct tegra_pcie *pcie)
{
	const struct tegra_pcie_soc_data *soc = pcie->soc_data;

	pcie->pex_clk = devm_clk_get(pcie->dev, "pex");
	if (IS_ERR(pcie->pex_clk))
		return PTR_ERR(pcie->pex_clk);

	pcie->afi_clk = devm_clk_get(pcie->dev, "afi");
	if (IS_ERR(pcie->afi_clk))
		return PTR_ERR(pcie->afi_clk);

	pcie->pcie_xclk = devm_clk_get(pcie->dev, "pcie_xclk");
	if (IS_ERR(pcie->pcie_xclk))
		return PTR_ERR(pcie->pcie_xclk);

	pcie->pll_e = devm_clk_get(pcie->dev, "pll_e");
	if (IS_ERR(pcie->pll_e))
		return PTR_ERR(pcie->pll_e);

	if (soc->has_cml_clk) {
		pcie->cml_clk = devm_clk_get(pcie->dev, "cml");
		if (IS_ERR(pcie->cml_clk))
			return PTR_ERR(pcie->cml_clk);
	}

	return 0;
}

static int tegra_pcie_get_resources(struct tegra_pcie *pcie)
{
	struct platform_device *pdev = to_platform_device(pcie->dev);
	struct resource *pads, *afi, *res;
	int err;

	err = tegra_pcie_clocks_get(pcie);
	if (err) {
		dev_err(&pdev->dev, "failed to get clocks: %d\n", err);
		return err;
	}

	err = tegra_pcie_power_on(pcie);
	if (err) {
		dev_err(&pdev->dev, "failed to power up: %d\n", err);
		return err;
	}

	pads = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pads");
	pcie->pads = devm_ioremap_resource(&pdev->dev, pads);
	if (IS_ERR(pcie->pads)) {
		err = PTR_ERR(pcie->pads);
		goto poweroff;
	}

	afi = platform_get_resource_byname(pdev, IORESOURCE_MEM, "afi");
	pcie->afi = devm_ioremap_resource(&pdev->dev, afi);
	if (IS_ERR(pcie->afi)) {
		err = PTR_ERR(pcie->afi);
		goto poweroff;
	}

	/* request configuration space, but remap later, on demand */
	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cs");
	if (!res) {
		err = -EADDRNOTAVAIL;
		goto poweroff;
	}

	pcie->cs = devm_request_mem_region(pcie->dev, res->start,
					   resource_size(res), res->name);
	if (!pcie->cs) {
		err = -EADDRNOTAVAIL;
		goto poweroff;
	}

	/* request interrupt */
	err = platform_get_irq_byname(pdev, "intr");
	if (err < 0) {
		dev_err(&pdev->dev, "failed to get IRQ: %d\n", err);
		goto poweroff;
	}

	pcie->irq = err;

	err = request_irq(pcie->irq, tegra_pcie_isr, IRQF_SHARED, "PCIE", pcie);
	if (err) {
		dev_err(&pdev->dev, "failed to register IRQ: %d\n", err);
		goto poweroff;
	}

	return 0;

poweroff:
	tegra_pcie_power_off(pcie);
	return err;
}

static int tegra_pcie_put_resources(struct tegra_pcie *pcie)
{
	if (pcie->irq > 0)
		free_irq(pcie->irq, pcie);

	tegra_pcie_power_off(pcie);
	return 0;
}

static int tegra_msi_alloc(struct tegra_msi *chip)
{
	int msi;

	mutex_lock(&chip->lock);

	msi = find_first_zero_bit(chip->used, INT_PCI_MSI_NR);
	if (msi < INT_PCI_MSI_NR)
		set_bit(msi, chip->used);
	else
		msi = -ENOSPC;

	mutex_unlock(&chip->lock);

	return msi;
}

static void tegra_msi_free(struct tegra_msi *chip, unsigned long irq)
{
	struct device *dev = chip->chip.dev;

	mutex_lock(&chip->lock);

	if (!test_bit(irq, chip->used))
		dev_err(dev, "trying to free unused MSI#%lu\n", irq);
	else
		clear_bit(irq, chip->used);

	mutex_unlock(&chip->lock);
}

static irqreturn_t tegra_pcie_msi_irq(int irq, void *data)
{
	struct tegra_pcie *pcie = data;
	struct tegra_msi *msi = &pcie->msi;
	unsigned int i, processed = 0;

	for (i = 0; i < 8; i++) {
		unsigned long reg = afi_readl(pcie, AFI_MSI_VEC0 + i * 4);

		while (reg) {
			unsigned int offset = find_first_bit(&reg, 32);
			unsigned int index = i * 32 + offset;
			unsigned int irq;

			/* clear the interrupt */
			afi_writel(pcie, 1 << offset, AFI_MSI_VEC0 + i * 4);

			irq = irq_find_mapping(msi->domain, index);
			if (irq) {
				if (test_bit(index, msi->used))
					generic_handle_irq(irq);
				else
					dev_info(pcie->dev, "unhandled MSI\n");
			} else {
				/*
				 * that's weird who triggered this?
				 * just clear it
				 */
				dev_info(pcie->dev, "unexpected MSI\n");
			}

			/* see if there's any more pending in this vector */
			reg = afi_readl(pcie, AFI_MSI_VEC0 + i * 4);

			processed++;
		}
	}

	return processed > 0 ? IRQ_HANDLED : IRQ_NONE;
}

static int tegra_msi_setup_irq(struct msi_chip *chip, struct pci_dev *pdev,
			       struct msi_desc *desc)
{
	struct tegra_msi *msi = to_tegra_msi(chip);
	struct msi_msg msg;
	unsigned int irq;
	int hwirq;

	hwirq = tegra_msi_alloc(msi);
	if (hwirq < 0)
		return hwirq;

	irq = irq_create_mapping(msi->domain, hwirq);
	if (!irq)
		return -EINVAL;

	irq_set_msi_desc(irq, desc);

	msg.address_lo = virt_to_phys((void *)msi->pages);
	/* 32 bit address only */
	msg.address_hi = 0;
	msg.data = hwirq;

	write_msi_msg(irq, &msg);

	return 0;
}

static void tegra_msi_teardown_irq(struct msi_chip *chip, unsigned int irq)
{
	struct tegra_msi *msi = to_tegra_msi(chip);
	struct irq_data *d = irq_get_irq_data(irq);

	tegra_msi_free(msi, d->hwirq);
}

static struct irq_chip tegra_msi_irq_chip = {
	.name = "Tegra PCIe MSI",
	.irq_enable = unmask_msi_irq,
	.irq_disable = mask_msi_irq,
	.irq_mask = mask_msi_irq,
	.irq_unmask = unmask_msi_irq,
};

static int tegra_msi_map(struct irq_domain *domain, unsigned int irq,
			 irq_hw_number_t hwirq)
{
	irq_set_chip_and_handler(irq, &tegra_msi_irq_chip, handle_simple_irq);
	irq_set_chip_data(irq, domain->host_data);
	set_irq_flags(irq, IRQF_VALID);

	tegra_cpuidle_pcie_irqs_in_use();

	return 0;
}

static const struct irq_domain_ops msi_domain_ops = {
	.map = tegra_msi_map,
};

static int tegra_pcie_enable_msi(struct tegra_pcie *pcie)
{
	struct platform_device *pdev = to_platform_device(pcie->dev);
	const struct tegra_pcie_soc_data *soc = pcie->soc_data;
	struct tegra_msi *msi = &pcie->msi;
	unsigned long base;
	int err;
	u32 reg;

	mutex_init(&msi->lock);

	msi->chip.dev = pcie->dev;
	msi->chip.setup_irq = tegra_msi_setup_irq;
	msi->chip.teardown_irq = tegra_msi_teardown_irq;

	msi->domain = irq_domain_add_linear(pcie->dev->of_node, INT_PCI_MSI_NR,
					    &msi_domain_ops, &msi->chip);
	if (!msi->domain) {
		dev_err(&pdev->dev, "failed to create IRQ domain\n");
		return -ENOMEM;
	}

	err = platform_get_irq_byname(pdev, "msi");
	if (err < 0) {
		dev_err(&pdev->dev, "failed to get IRQ: %d\n", err);
		goto err;
	}

	msi->irq = err;

	err = request_irq(msi->irq, tegra_pcie_msi_irq, 0,
			  tegra_msi_irq_chip.name, pcie);
	if (err < 0) {
		dev_err(&pdev->dev, "failed to request IRQ: %d\n", err);
		goto err;
	}

	/* setup AFI/FPCI range */
	msi->pages = __get_free_pages(GFP_KERNEL, 0);
	base = virt_to_phys((void *)msi->pages);

	afi_writel(pcie, base >> soc->msi_base_shift, AFI_MSI_FPCI_BAR_ST);
	afi_writel(pcie, base, AFI_MSI_AXI_BAR_ST);
	/* this register is in 4K increments */
	afi_writel(pcie, 1, AFI_MSI_BAR_SZ);

	/* enable all MSI vectors */
	afi_writel(pcie, 0xffffffff, AFI_MSI_EN_VEC0);
	afi_writel(pcie, 0xffffffff, AFI_MSI_EN_VEC1);
	afi_writel(pcie, 0xffffffff, AFI_MSI_EN_VEC2);
	afi_writel(pcie, 0xffffffff, AFI_MSI_EN_VEC3);
	afi_writel(pcie, 0xffffffff, AFI_MSI_EN_VEC4);
	afi_writel(pcie, 0xffffffff, AFI_MSI_EN_VEC5);
	afi_writel(pcie, 0xffffffff, AFI_MSI_EN_VEC6);
	afi_writel(pcie, 0xffffffff, AFI_MSI_EN_VEC7);

	/* and unmask the MSI interrupt */
	reg = afi_readl(pcie, AFI_INTR_MASK);
	reg |= AFI_INTR_MASK_MSI_MASK;
	afi_writel(pcie, reg, AFI_INTR_MASK);

	return 0;

err:
	irq_domain_remove(msi->domain);
	return err;
}

static int tegra_pcie_disable_msi(struct tegra_pcie *pcie)
{
	struct tegra_msi *msi = &pcie->msi;
	unsigned int i, irq;
	u32 value;

	/* mask the MSI interrupt */
	value = afi_readl(pcie, AFI_INTR_MASK);
	value &= ~AFI_INTR_MASK_MSI_MASK;
	afi_writel(pcie, value, AFI_INTR_MASK);

	/* disable all MSI vectors */
	afi_writel(pcie, 0, AFI_MSI_EN_VEC0);
	afi_writel(pcie, 0, AFI_MSI_EN_VEC1);
	afi_writel(pcie, 0, AFI_MSI_EN_VEC2);
	afi_writel(pcie, 0, AFI_MSI_EN_VEC3);
	afi_writel(pcie, 0, AFI_MSI_EN_VEC4);
	afi_writel(pcie, 0, AFI_MSI_EN_VEC5);
	afi_writel(pcie, 0, AFI_MSI_EN_VEC6);
	afi_writel(pcie, 0, AFI_MSI_EN_VEC7);

	free_pages(msi->pages, 0);

	if (msi->irq > 0)
		free_irq(msi->irq, pcie);

	for (i = 0; i < INT_PCI_MSI_NR; i++) {
		irq = irq_find_mapping(msi->domain, i);
		if (irq > 0)
			irq_dispose_mapping(irq);
	}

	irq_domain_remove(msi->domain);

	return 0;
}

static int tegra_pcie_get_xbar_config(struct tegra_pcie *pcie, u32 lanes,
				      u32 *xbar)
{
	struct device_node *np = pcie->dev->of_node;

	if (of_device_is_compatible(np, "nvidia,tegra30-pcie")) {
		switch (lanes) {
		case 0x00000204:
			dev_info(pcie->dev, "4x1, 2x1 configuration\n");
			*xbar = AFI_PCIE_CONFIG_SM2TMS0_XBAR_CONFIG_420;
			return 0;

		case 0x00020202:
			dev_info(pcie->dev, "2x3 configuration\n");
			*xbar = AFI_PCIE_CONFIG_SM2TMS0_XBAR_CONFIG_222;
			return 0;

		case 0x00010104:
			dev_info(pcie->dev, "4x1, 1x2 configuration\n");
			*xbar = AFI_PCIE_CONFIG_SM2TMS0_XBAR_CONFIG_411;
			return 0;
		}
	} else if (of_device_is_compatible(np, "nvidia,tegra20-pcie")) {
		switch (lanes) {
		case 0x00000004:
			dev_info(pcie->dev, "single-mode configuration\n");
			*xbar = AFI_PCIE_CONFIG_SM2TMS0_XBAR_CONFIG_SINGLE;
			return 0;

		case 0x00000202:
			dev_info(pcie->dev, "dual-mode configuration\n");
			*xbar = AFI_PCIE_CONFIG_SM2TMS0_XBAR_CONFIG_DUAL;
			return 0;
		}
	}

	return -EINVAL;
}

static int tegra_pcie_parse_dt(struct tegra_pcie *pcie)
{
	const struct tegra_pcie_soc_data *soc = pcie->soc_data;
	struct device_node *np = pcie->dev->of_node, *port;
	struct of_pci_range_parser parser;
	struct of_pci_range range;
	struct resource res;
	u32 lanes = 0;
	int err;

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

	pcie->vdd_supply = devm_regulator_get(pcie->dev, "vdd");
	if (IS_ERR(pcie->vdd_supply))
		return PTR_ERR(pcie->vdd_supply);

	pcie->pex_clk_supply = devm_regulator_get(pcie->dev, "pex-clk");
	if (IS_ERR(pcie->pex_clk_supply))
		return PTR_ERR(pcie->pex_clk_supply);

	if (soc->has_avdd_supply) {
		pcie->avdd_supply = devm_regulator_get(pcie->dev, "avdd");
		if (IS_ERR(pcie->avdd_supply))
			return PTR_ERR(pcie->avdd_supply);
	}

	for_each_of_pci_range(&parser, &range) {
		of_pci_range_to_resource(&range, np, &res);

		switch (res.flags & IORESOURCE_TYPE_BITS) {
		case IORESOURCE_IO:
			memcpy(&pcie->io, &res, sizeof(res));
			pcie->io.name = "I/O";
			break;

		case IORESOURCE_MEM:
			if (res.flags & IORESOURCE_PREFETCH) {
				memcpy(&pcie->prefetch, &res, sizeof(res));
				pcie->prefetch.name = "PREFETCH";
			} else {
				memcpy(&pcie->mem, &res, sizeof(res));
				pcie->mem.name = "MEM";
			}
			break;
		}
	}

	err = of_pci_parse_bus_range(np, &pcie->busn);
	if (err < 0) {
		dev_err(pcie->dev, "failed to parse ranges property: %d\n",
			err);
		pcie->busn.name = np->name;
		pcie->busn.start = 0;
		pcie->busn.end = 0xff;
		pcie->busn.flags = IORESOURCE_BUS;
	}

	/* parse root ports */
	for_each_child_of_node(np, port) {
		struct tegra_pcie_port *rp;
		unsigned int index;
		u32 value;

		err = of_pci_get_devfn(port);
		if (err < 0) {
			dev_err(pcie->dev, "failed to parse address: %d\n",
				err);
			return err;
		}

		index = PCI_SLOT(err);

		if (index < 1 || index > soc->num_ports) {
			dev_err(pcie->dev, "invalid port number: %d\n", index);
			return -EINVAL;
		}

		index--;

		err = of_property_read_u32(port, "nvidia,num-lanes", &value);
		if (err < 0) {
			dev_err(pcie->dev, "failed to parse # of lanes: %d\n",
				err);
			return err;
		}

		if (value > 16) {
			dev_err(pcie->dev, "invalid # of lanes: %u\n", value);
			return -EINVAL;
		}

		lanes |= value << (index << 3);

		if (!of_device_is_available(port))
			continue;

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

		err = of_address_to_resource(port, 0, &rp->regs);
		if (err < 0) {
			dev_err(pcie->dev, "failed to parse address: %d\n",
				err);
			return err;
		}

		INIT_LIST_HEAD(&rp->list);
		rp->index = index;
		rp->lanes = value;
		rp->pcie = pcie;

		rp->base = devm_ioremap_resource(pcie->dev, &rp->regs);
		if (IS_ERR(rp->base))
			return PTR_ERR(rp->base);

		list_add_tail(&rp->list, &pcie->ports);
	}

	err = tegra_pcie_get_xbar_config(pcie, lanes, &pcie->xbar_config);
	if (err < 0) {
		dev_err(pcie->dev, "invalid lane configuration\n");
		return err;
	}

	return 0;
}

/*
 * FIXME: If there are no PCIe cards attached, then calling this function
 * can result in the increase of the bootup time as there are big timeout
 * loops.
 */
#define TEGRA_PCIE_LINKUP_TIMEOUT	200	/* up to 1.2 seconds */
static bool tegra_pcie_port_check_link(struct tegra_pcie_port *port)
{
	unsigned int retries = 3;
	unsigned long value;

	do {
		unsigned int timeout = TEGRA_PCIE_LINKUP_TIMEOUT;

		do {
			value = readl(port->base + RP_VEND_XP);

			if (value & RP_VEND_XP_DL_UP)
				break;

			usleep_range(1000, 2000);
		} while (--timeout);

		if (!timeout) {
			dev_err(port->pcie->dev, "link %u down, retrying\n",
				port->index);
			goto retry;
		}

		timeout = TEGRA_PCIE_LINKUP_TIMEOUT;

		do {
			value = readl(port->base + RP_LINK_CONTROL_STATUS);

			if (value & RP_LINK_CONTROL_STATUS_DL_LINK_ACTIVE)
				return true;

			usleep_range(1000, 2000);
		} while (--timeout);

retry:
		tegra_pcie_port_reset(port);
	} while (--retries);

	return false;
}

static int tegra_pcie_enable(struct tegra_pcie *pcie)
{
	struct tegra_pcie_port *port, *tmp;
	struct hw_pci hw;

	list_for_each_entry_safe(port, tmp, &pcie->ports, list) {
		dev_info(pcie->dev, "probing port %u, using %u lanes\n",
			 port->index, port->lanes);

		tegra_pcie_port_enable(port);

		if (tegra_pcie_port_check_link(port))
			continue;

		dev_info(pcie->dev, "link %u down, ignoring\n", port->index);

		tegra_pcie_port_disable(port);
		tegra_pcie_port_free(port);
	}

	memset(&hw, 0, sizeof(hw));

	hw.nr_controllers = 1;
	hw.private_data = (void **)&pcie;
	hw.setup = tegra_pcie_setup;
	hw.map_irq = tegra_pcie_map_irq;
	hw.add_bus = tegra_pcie_add_bus;
	hw.scan = tegra_pcie_scan_bus;
	hw.ops = &tegra_pcie_ops;

	pci_common_init_dev(pcie->dev, &hw);

	return 0;
}

static const struct tegra_pcie_soc_data tegra20_pcie_data = {
	.num_ports = 2,
	.msi_base_shift = 0,
	.pads_pll_ctl = PADS_PLL_CTL_TEGRA20,
	.tx_ref_sel = PADS_PLL_CTL_TXCLKREF_DIV10,
	.has_pex_clkreq_en = false,
	.has_pex_bias_ctrl = false,
	.has_intr_prsnt_sense = false,
	.has_avdd_supply = false,
	.has_cml_clk = false,
};

static const struct tegra_pcie_soc_data tegra30_pcie_data = {
	.num_ports = 3,
	.msi_base_shift = 8,
	.pads_pll_ctl = PADS_PLL_CTL_TEGRA30,
	.tx_ref_sel = PADS_PLL_CTL_TXCLKREF_BUF_EN,
	.has_pex_clkreq_en = true,
	.has_pex_bias_ctrl = true,
	.has_intr_prsnt_sense = true,
	.has_avdd_supply = true,
	.has_cml_clk = true,
};

static const struct of_device_id tegra_pcie_of_match[] = {
	{ .compatible = "nvidia,tegra30-pcie", .data = &tegra30_pcie_data },
	{ .compatible = "nvidia,tegra20-pcie", .data = &tegra20_pcie_data },
	{ },
};
MODULE_DEVICE_TABLE(of, tegra_pcie_of_match);

static int tegra_pcie_probe(struct platform_device *pdev)
{
	const struct of_device_id *match;
	struct tegra_pcie *pcie;
	int err;

	match = of_match_device(tegra_pcie_of_match, &pdev->dev);
	if (!match)
		return -ENODEV;

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

	INIT_LIST_HEAD(&pcie->busses);
	INIT_LIST_HEAD(&pcie->ports);
	pcie->soc_data = match->data;
	pcie->dev = &pdev->dev;

	err = tegra_pcie_parse_dt(pcie);
	if (err < 0)
		return err;

	pcibios_min_mem = 0;

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

	err = tegra_pcie_enable_controller(pcie);
	if (err)
		goto put_resources;

	/* setup the AFI address translations */
	tegra_pcie_setup_translations(pcie);

	if (IS_ENABLED(CONFIG_PCI_MSI)) {
		err = tegra_pcie_enable_msi(pcie);
		if (err < 0) {
			dev_err(&pdev->dev,
				"failed to enable MSI support: %d\n",
				err);
			goto put_resources;
		}
	}

	err = tegra_pcie_enable(pcie);
	if (err < 0) {
		dev_err(&pdev->dev, "failed to enable PCIe ports: %d\n", err);
		goto disable_msi;
	}

	platform_set_drvdata(pdev, pcie);
	return 0;

disable_msi:
	if (IS_ENABLED(CONFIG_PCI_MSI))
		tegra_pcie_disable_msi(pcie);
put_resources:
	tegra_pcie_put_resources(pcie);
	return err;
}

static struct platform_driver tegra_pcie_driver = {
	.driver = {
		.name = "tegra-pcie",
		.owner = THIS_MODULE,
		.of_match_table = tegra_pcie_of_match,
		.suppress_bind_attrs = true,
	},
	.probe = tegra_pcie_probe,
};
module_platform_driver(tegra_pcie_driver);

MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
MODULE_DESCRIPTION("NVIDIA Tegra PCIe driver");
MODULE_LICENSE("GPLv2");