/*
 * 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/debugfs.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/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/reset.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/regulator/consumer.h>

#include <soc/tegra/cpuidle.h>
#include <soc/tegra/pmc.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_INI_SLAVE_ERROR	1
#define  AFI_INTR_INI_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_AXI_DECODE_ERROR	8
#define  AFI_INTR_FPCI_TIMEOUT		9
#define  AFI_INTR_PE_PRSNT_SENSE	10
#define  AFI_INTR_PE_CLKREQ_SENSE	11
#define  AFI_INTR_CLKCLAMP_SENSE	12
#define  AFI_INTR_RDY4PD_SENSE		13
#define  AFI_INTR_P2P_ERROR		14

#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_X2_X1	(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_X4_X1	(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_PEX_CTRL_OVERRIDE_EN	(1 << 4)

#define AFI_PLLE_CONTROL		0x160
#define  AFI_PLLE_CONTROL_BYPASS_PADS2PLLE_CONTROL (1 << 9)
#define  AFI_PLLE_CONTROL_PADS2PLLE_CONTROL_EN (1 << 1)

#define AFI_PEXBIAS_CTRL_0		0x168

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

#define RP_PRIV_MISC	0x00000FE0
#define  RP_PRIV_MISC_PRSNT_MAP_EP_PRSNT (0xE << 0)
#define  RP_PRIV_MISC_PRSNT_MAP_EP_ABSNT (0xF << 0)

#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
#define PADS_REFCLK_BIAS			0x000000D0

/*
 * 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_controller 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_cml_clk;
	bool has_gen2;
};

static inline struct tegra_msi *to_tegra_msi(struct msi_controller *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 buses;
	struct resource *cs;

	struct resource all;
	struct resource io;
	struct resource pio;
	struct resource mem;
	struct resource prefetch;
	struct resource busn;

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

	struct reset_control *pex_rst;
	struct reset_control *afi_rst;
	struct reset_control *pcie_xrst;

	struct phy *phy;

	struct tegra_msi msi;

	struct list_head ports;
	unsigned int num_ports;
	u32 xbar_config;

	struct regulator_bulk_data *supplies;
	unsigned int num_supplies;

	const struct tegra_pcie_soc_data *soc_data;
	struct dentry *debugfs;
};

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_16M + 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 exists, 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->buses, list)
		if (bus->nr == busnr)
			return (void __iomem *)bus->area->addr;

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

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

	return (void __iomem *)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 struct pci_ops tegra_pcie_ops = {
	.map_bus = tegra_pcie_conf_address,
	.read = pci_generic_config_read32,
	.write = pci_generic_config_write32,
};

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;

	value |= AFI_PEX_CTRL_OVERRIDE_EN;

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

	tegra_pcie_port_reset(port);
}

static void tegra_pcie_port_disable(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;

	/* 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);

	if (soc->has_pex_clkreq_en)
		value &= ~AFI_PEX_CTRL_CLKREQ_EN;

	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);
}

/* 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);
	int err;

	err = devm_request_resource(pcie->dev, &pcie->all, &pcie->mem);
	if (err < 0)
		return err;

	err = devm_request_resource(pcie->dev, &pcie->all, &pcie->prefetch);
	if (err)
		return err;

	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(pcie->pio.start, 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);
	int irq;

	tegra_cpuidle_pcie_irqs_in_use();

	irq = of_irq_parse_and_map_pci(pdev, slot, pin);
	if (!irq)
		irq = pcie->irq;

	return irq;
}

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",
		"Legacy interrupt",
		"Response decoding error",
		"AXI response decoding error",
		"Transaction timeout",
		"Slot present pin change",
		"Slot clock request change",
		"TMS clock ramp change",
		"TMS ready for power down",
		"Peer2Peer error",
	};
	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_pll_wait(struct tegra_pcie *pcie, unsigned long timeout)
{
	const struct tegra_pcie_soc_data *soc = pcie->soc_data;
	u32 value;

	timeout = jiffies + msecs_to_jiffies(timeout);

	while (time_before(jiffies, timeout)) {
		value = pads_readl(pcie, soc->pads_pll_ctl);
		if (value & PADS_PLL_CTL_LOCKDET)
			return 0;
	}

	return -ETIMEDOUT;
}

static int tegra_pcie_phy_enable(struct tegra_pcie *pcie)
{
	const struct tegra_pcie_soc_data *soc = pcie->soc_data;
	u32 value;
	int err;

	/* initialize 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);

	/* reset PLL */
	value = pads_readl(pcie, soc->pads_pll_ctl);
	value &= ~PADS_PLL_CTL_RST_B4SM;
	pads_writel(pcie, value, soc->pads_pll_ctl);

	usleep_range(20, 100);

	/* 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 */
	err = tegra_pcie_pll_wait(pcie, 500);
	if (err < 0) {
		dev_err(pcie->dev, "PLL failed to lock: %d\n", err);
		return err;
	}

	/* 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);

	return 0;
}

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 long value;
	int err;

	/* enable PLL power down */
	if (pcie->phy) {
		value = afi_readl(pcie, AFI_PLLE_CONTROL);
		value &= ~AFI_PLLE_CONTROL_BYPASS_PADS2PLLE_CONTROL;
		value |= AFI_PLLE_CONTROL_PADS2PLLE_CONTROL_EN;
		afi_writel(pcie, value, AFI_PLLE_CONTROL);
	}

	/* 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);

	if (soc->has_gen2) {
		value = afi_readl(pcie, AFI_FUSE);
		value &= ~AFI_FUSE_PCIE_T0_GEN2_DIS;
		afi_writel(pcie, value, AFI_FUSE);
	} else {
		value = afi_readl(pcie, AFI_FUSE);
		value |= AFI_FUSE_PCIE_T0_GEN2_DIS;
		afi_writel(pcie, value, AFI_FUSE);
	}

	if (!pcie->phy)
		err = tegra_pcie_phy_enable(pcie);
	else
		err = phy_power_on(pcie->phy);

	if (err < 0) {
		dev_err(pcie->dev, "failed to power on PHY: %d\n", err);
		return err;
	}

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

	/* 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)
{
	int err;

	/* TODO: disable and unprepare clocks? */

	err = phy_power_off(pcie->phy);
	if (err < 0)
		dev_warn(pcie->dev, "failed to power off PHY: %d\n", err);

	reset_control_assert(pcie->pcie_xrst);
	reset_control_assert(pcie->afi_rst);
	reset_control_assert(pcie->pex_rst);

	tegra_powergate_power_off(TEGRA_POWERGATE_PCIE);

	err = regulator_bulk_disable(pcie->num_supplies, pcie->supplies);
	if (err < 0)
		dev_warn(pcie->dev, "failed to disable regulators: %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;

	reset_control_assert(pcie->pcie_xrst);
	reset_control_assert(pcie->afi_rst);
	reset_control_assert(pcie->pex_rst);

	tegra_powergate_power_off(TEGRA_POWERGATE_PCIE);

	/* enable regulators */
	err = regulator_bulk_enable(pcie->num_supplies, pcie->supplies);
	if (err < 0)
		dev_err(pcie->dev, "failed to enable regulators: %d\n", err);

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

	reset_control_deassert(pcie->afi_rst);

	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->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_resets_get(struct tegra_pcie *pcie)
{
	pcie->pex_rst = devm_reset_control_get(pcie->dev, "pex");
	if (IS_ERR(pcie->pex_rst))
		return PTR_ERR(pcie->pex_rst);

	pcie->afi_rst = devm_reset_control_get(pcie->dev, "afi");
	if (IS_ERR(pcie->afi_rst))
		return PTR_ERR(pcie->afi_rst);

	pcie->pcie_xrst = devm_reset_control_get(pcie->dev, "pcie_x");
	if (IS_ERR(pcie->pcie_xrst))
		return PTR_ERR(pcie->pcie_xrst);

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

	pcie->phy = devm_phy_optional_get(pcie->dev, "pcie");
	if (IS_ERR(pcie->phy)) {
		err = PTR_ERR(pcie->phy);
		dev_err(&pdev->dev, "failed to get PHY: %d\n", err);
		return err;
	}

	err = phy_init(pcie->phy);
	if (err < 0) {
		dev_err(&pdev->dev, "failed to initialize PHY: %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)
{
	int err;

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

	tegra_pcie_power_off(pcie);

	err = phy_exit(pcie->phy);
	if (err < 0)
		dev_err(pcie->dev, "failed to teardown PHY: %d\n", err);

	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_controller *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) {
		tegra_msi_free(msi, hwirq);
		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;

	pci_write_msi_msg(irq, &msg);

	return 0;
}

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

	irq_dispose_mapping(irq);
	tegra_msi_free(msi, hwirq);
}

static struct irq_chip tegra_msi_irq_chip = {
	.name = "Tegra PCIe MSI",
	.irq_enable = pci_msi_unmask_irq,
	.irq_disable = pci_msi_mask_irq,
	.irq_mask = pci_msi_mask_irq,
	.irq_unmask = pci_msi_unmask_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,tegra124-pcie")) {
		switch (lanes) {
		case 0x0000104:
			dev_info(pcie->dev, "4x1, 1x1 configuration\n");
			*xbar = AFI_PCIE_CONFIG_SM2TMS0_XBAR_CONFIG_X4_X1;
			return 0;

		case 0x0000102:
			dev_info(pcie->dev, "2x1, 1x1 configuration\n");
			*xbar = AFI_PCIE_CONFIG_SM2TMS0_XBAR_CONFIG_X2_X1;
			return 0;
		}
	} else 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;
}

/*
 * Check whether a given set of supplies is available in a device tree node.
 * This is used to check whether the new or the legacy device tree bindings
 * should be used.
 */
static bool of_regulator_bulk_available(struct device_node *np,
					struct regulator_bulk_data *supplies,
					unsigned int num_supplies)
{
	char property[32];
	unsigned int i;

	for (i = 0; i < num_supplies; i++) {
		snprintf(property, 32, "%s-supply", supplies[i].supply);

		if (of_find_property(np, property, NULL) == NULL)
			return false;
	}

	return true;
}

/*
 * Old versions of the device tree binding for this device used a set of power
 * supplies that didn't match the hardware inputs. This happened to work for a
 * number of cases but is not future proof. However to preserve backwards-
 * compatibility with old device trees, this function will try to use the old
 * set of supplies.
 */
static int tegra_pcie_get_legacy_regulators(struct tegra_pcie *pcie)
{
	struct device_node *np = pcie->dev->of_node;

	if (of_device_is_compatible(np, "nvidia,tegra30-pcie"))
		pcie->num_supplies = 3;
	else if (of_device_is_compatible(np, "nvidia,tegra20-pcie"))
		pcie->num_supplies = 2;

	if (pcie->num_supplies == 0) {
		dev_err(pcie->dev, "device %s not supported in legacy mode\n",
			np->full_name);
		return -ENODEV;
	}

	pcie->supplies = devm_kcalloc(pcie->dev, pcie->num_supplies,
				      sizeof(*pcie->supplies),
				      GFP_KERNEL);
	if (!pcie->supplies)
		return -ENOMEM;

	pcie->supplies[0].supply = "pex-clk";
	pcie->supplies[1].supply = "vdd";

	if (pcie->num_supplies > 2)
		pcie->supplies[2].supply = "avdd";

	return devm_regulator_bulk_get(pcie->dev, pcie->num_supplies,
				       pcie->supplies);
}

/*
 * Obtains the list of regulators required for a particular generation of the
 * IP block.
 *
 * This would've been nice to do simply by providing static tables for use
 * with the regulator_bulk_*() API, but unfortunately Tegra30 is a bit quirky
 * in that it has two pairs or AVDD_PEX and VDD_PEX supplies (PEXA and PEXB)
 * and either seems to be optional depending on which ports are being used.
 */
static int tegra_pcie_get_regulators(struct tegra_pcie *pcie, u32 lane_mask)
{
	struct device_node *np = pcie->dev->of_node;
	unsigned int i = 0;

	if (of_device_is_compatible(np, "nvidia,tegra124-pcie")) {
		pcie->num_supplies = 7;

		pcie->supplies = devm_kcalloc(pcie->dev, pcie->num_supplies,
					      sizeof(*pcie->supplies),
					      GFP_KERNEL);
		if (!pcie->supplies)
			return -ENOMEM;

		pcie->supplies[i++].supply = "avddio-pex";
		pcie->supplies[i++].supply = "dvddio-pex";
		pcie->supplies[i++].supply = "avdd-pex-pll";
		pcie->supplies[i++].supply = "hvdd-pex";
		pcie->supplies[i++].supply = "hvdd-pex-pll-e";
		pcie->supplies[i++].supply = "vddio-pex-ctl";
		pcie->supplies[i++].supply = "avdd-pll-erefe";
	} else if (of_device_is_compatible(np, "nvidia,tegra30-pcie")) {
		bool need_pexa = false, need_pexb = false;

		/* VDD_PEXA and AVDD_PEXA supply lanes 0 to 3 */
		if (lane_mask & 0x0f)
			need_pexa = true;

		/* VDD_PEXB and AVDD_PEXB supply lanes 4 to 5 */
		if (lane_mask & 0x30)
			need_pexb = true;

		pcie->num_supplies = 4 + (need_pexa ? 2 : 0) +
					 (need_pexb ? 2 : 0);

		pcie->supplies = devm_kcalloc(pcie->dev, pcie->num_supplies,
					      sizeof(*pcie->supplies),
					      GFP_KERNEL);
		if (!pcie->supplies)
			return -ENOMEM;

		pcie->supplies[i++].supply = "avdd-pex-pll";
		pcie->supplies[i++].supply = "hvdd-pex";
		pcie->supplies[i++].supply = "vddio-pex-ctl";
		pcie->supplies[i++].supply = "avdd-plle";

		if (need_pexa) {
			pcie->supplies[i++].supply = "avdd-pexa";
			pcie->supplies[i++].supply = "vdd-pexa";
		}

		if (need_pexb) {
			pcie->supplies[i++].supply = "avdd-pexb";
			pcie->supplies[i++].supply = "vdd-pexb";
		}
	} else if (of_device_is_compatible(np, "nvidia,tegra20-pcie")) {
		pcie->num_supplies = 5;

		pcie->supplies = devm_kcalloc(pcie->dev, pcie->num_supplies,
					      sizeof(*pcie->supplies),
					      GFP_KERNEL);
		if (!pcie->supplies)
			return -ENOMEM;

		pcie->supplies[0].supply = "avdd-pex";
		pcie->supplies[1].supply = "vdd-pex";
		pcie->supplies[2].supply = "avdd-pex-pll";
		pcie->supplies[3].supply = "avdd-plle";
		pcie->supplies[4].supply = "vddio-pex-clk";
	}

	if (of_regulator_bulk_available(pcie->dev->of_node, pcie->supplies,
					pcie->num_supplies))
		return devm_regulator_bulk_get(pcie->dev, pcie->num_supplies,
					       pcie->supplies);

	/*
	 * If not all regulators are available for this new scheme, assume
	 * that the device tree complies with an older version of the device
	 * tree binding.
	 */
	dev_info(pcie->dev, "using legacy DT binding for power supplies\n");

	devm_kfree(pcie->dev, pcie->supplies);
	pcie->num_supplies = 0;

	return tegra_pcie_get_legacy_regulators(pcie);
}

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;
	u32 lanes = 0, mask = 0;
	unsigned int lane = 0;
	struct resource res;
	int err;

	memset(&pcie->all, 0, sizeof(pcie->all));
	pcie->all.flags = IORESOURCE_MEM;
	pcie->all.name = np->full_name;
	pcie->all.start = ~0;
	pcie->all.end = 0;

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

	for_each_of_pci_range(&parser, &range) {
		err = of_pci_range_to_resource(&range, np, &res);
		if (err < 0)
			return err;

		switch (res.flags & IORESOURCE_TYPE_BITS) {
		case IORESOURCE_IO:
			memcpy(&pcie->pio, &res, sizeof(res));
			pcie->pio.name = np->full_name;

			/*
			 * The Tegra PCIe host bridge uses this to program the
			 * mapping of the I/O space to the physical address,
			 * so we override the .start and .end fields here that
			 * of_pci_range_to_resource() converted to I/O space.
			 * We also set the IORESOURCE_MEM type to clarify that
			 * the resource is in the physical memory space.
			 */
			pcie->io.start = range.cpu_addr;
			pcie->io.end = range.cpu_addr + range.size - 1;
			pcie->io.flags = IORESOURCE_MEM;
			pcie->io.name = "I/O";

			memcpy(&res, &pcie->io, sizeof(res));
			break;

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

		if (res.start <= pcie->all.start)
			pcie->all.start = res.start;

		if (res.end >= pcie->all.end)
			pcie->all.end = res.end;
	}

	err = devm_request_resource(pcie->dev, &iomem_resource, &pcie->all);
	if (err < 0)
		return err;

	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)) {
			lane += value;
			continue;
		}

		mask |= ((1 << value) - 1) << lane;
		lane += value;

		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;
	}

	err = tegra_pcie_get_regulators(pcie, mask);
	if (err < 0)
		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;

	/* override presence detection */
	value = readl(port->base + RP_PRIV_MISC);
	value &= ~RP_PRIV_MISC_PRSNT_MAP_EP_ABSNT;
	value |= RP_PRIV_MISC_PRSNT_MAP_EP_PRSNT;
	writel(value, port->base + RP_PRIV_MISC);

	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));

#ifdef CONFIG_PCI_MSI
	hw.msi_ctrl = &pcie->msi.chip;
#endif

	hw.nr_controllers = 1;
	hw.private_data = (void **)&pcie;
	hw.setup = tegra_pcie_setup;
	hw.map_irq = tegra_pcie_map_irq;
	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_cml_clk = false,
	.has_gen2 = 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_cml_clk = true,
	.has_gen2 = false,
};

static const struct tegra_pcie_soc_data tegra124_pcie_data = {
	.num_ports = 2,
	.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_cml_clk = true,
	.has_gen2 = true,
};

static const struct of_device_id tegra_pcie_of_match[] = {
	{ .compatible = "nvidia,tegra124-pcie", .data = &tegra124_pcie_data },
	{ .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 void *tegra_pcie_ports_seq_start(struct seq_file *s, loff_t *pos)
{
	struct tegra_pcie *pcie = s->private;

	if (list_empty(&pcie->ports))
		return NULL;

	seq_printf(s, "Index  Status\n");

	return seq_list_start(&pcie->ports, *pos);
}

static void *tegra_pcie_ports_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
	struct tegra_pcie *pcie = s->private;

	return seq_list_next(v, &pcie->ports, pos);
}

static void tegra_pcie_ports_seq_stop(struct seq_file *s, void *v)
{
}

static int tegra_pcie_ports_seq_show(struct seq_file *s, void *v)
{
	bool up = false, active = false;
	struct tegra_pcie_port *port;
	unsigned int value;

	port = list_entry(v, struct tegra_pcie_port, list);

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

	if (value & RP_VEND_XP_DL_UP)
		up = true;

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

	if (value & RP_LINK_CONTROL_STATUS_DL_LINK_ACTIVE)
		active = true;

	seq_printf(s, "%2u     ", port->index);

	if (up)
		seq_printf(s, "up");

	if (active) {
		if (up)
			seq_printf(s, ", ");

		seq_printf(s, "active");
	}

	seq_printf(s, "\n");
	return 0;
}

static const struct seq_operations tegra_pcie_ports_seq_ops = {
	.start = tegra_pcie_ports_seq_start,
	.next = tegra_pcie_ports_seq_next,
	.stop = tegra_pcie_ports_seq_stop,
	.show = tegra_pcie_ports_seq_show,
};

static int tegra_pcie_ports_open(struct inode *inode, struct file *file)
{
	struct tegra_pcie *pcie = inode->i_private;
	struct seq_file *s;
	int err;

	err = seq_open(file, &tegra_pcie_ports_seq_ops);
	if (err)
		return err;

	s = file->private_data;
	s->private = pcie;

	return 0;
}

static const struct file_operations tegra_pcie_ports_ops = {
	.owner = THIS_MODULE,
	.open = tegra_pcie_ports_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = seq_release,
};

static int tegra_pcie_debugfs_init(struct tegra_pcie *pcie)
{
	struct dentry *file;

	pcie->debugfs = debugfs_create_dir("pcie", NULL);
	if (!pcie->debugfs)
		return -ENOMEM;

	file = debugfs_create_file("ports", S_IFREG | S_IRUGO, pcie->debugfs,
				   pcie, &tegra_pcie_ports_ops);
	if (!file)
		goto remove;

	return 0;

remove:
	debugfs_remove_recursive(pcie->debugfs);
	pcie->debugfs = NULL;
	return -ENOMEM;
}

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->buses);
	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;
	}

	if (IS_ENABLED(CONFIG_DEBUG_FS)) {
		err = tegra_pcie_debugfs_init(pcie);
		if (err < 0)
			dev_err(&pdev->dev, "failed to setup debugfs: %d\n",
				err);
	}

	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",
		.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("GPL v2");