/*
 * PCIe driver for Marvell Armada 370 and Armada XP SoCs
 *
 * Author: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2.  This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/mbus.h>
#include <linux/msi.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_gpio.h>
#include <linux/of_pci.h>
#include <linux/of_platform.h>

/*
 * PCIe unit register offsets.
 */
#define PCIE_DEV_ID_OFF         0x0000
#define PCIE_CMD_OFF            0x0004
#define PCIE_DEV_REV_OFF        0x0008
#define PCIE_BAR_LO_OFF(n)      (0x0010 + ((n) << 3))
#define PCIE_BAR_HI_OFF(n)      (0x0014 + ((n) << 3))
#define PCIE_CAP_PCIEXP         0x0060
#define PCIE_HEADER_LOG_4_OFF   0x0128
#define PCIE_BAR_CTRL_OFF(n)    (0x1804 + (((n) - 1) * 4))
#define PCIE_WIN04_CTRL_OFF(n)  (0x1820 + ((n) << 4))
#define PCIE_WIN04_BASE_OFF(n)  (0x1824 + ((n) << 4))
#define PCIE_WIN04_REMAP_OFF(n) (0x182c + ((n) << 4))
#define PCIE_WIN5_CTRL_OFF      0x1880
#define PCIE_WIN5_BASE_OFF      0x1884
#define PCIE_WIN5_REMAP_OFF     0x188c
#define PCIE_CONF_ADDR_OFF      0x18f8
#define  PCIE_CONF_ADDR_EN              0x80000000
#define  PCIE_CONF_REG(r)               ((((r) & 0xf00) << 16) | ((r) & 0xfc))
#define  PCIE_CONF_BUS(b)               (((b) & 0xff) << 16)
#define  PCIE_CONF_DEV(d)               (((d) & 0x1f) << 11)
#define  PCIE_CONF_FUNC(f)              (((f) & 0x7) << 8)
#define  PCIE_CONF_ADDR(bus, devfn, where) \
        (PCIE_CONF_BUS(bus) | PCIE_CONF_DEV(PCI_SLOT(devfn))    | \
         PCIE_CONF_FUNC(PCI_FUNC(devfn)) | PCIE_CONF_REG(where) | \
         PCIE_CONF_ADDR_EN)
#define PCIE_CONF_DATA_OFF      0x18fc
#define PCIE_MASK_OFF           0x1910
#define  PCIE_MASK_ENABLE_INTS          0x0f000000
#define PCIE_CTRL_OFF           0x1a00
#define  PCIE_CTRL_X1_MODE              0x0001
#define PCIE_STAT_OFF           0x1a04
#define  PCIE_STAT_BUS                  0xff00
#define  PCIE_STAT_DEV                  0x1f0000
#define  PCIE_STAT_LINK_DOWN            BIT(0)
#define PCIE_RC_RTSTA           0x1a14
#define PCIE_DEBUG_CTRL         0x1a60
#define  PCIE_DEBUG_SOFT_RESET          BIT(20)

enum {
        PCISWCAP = PCI_BRIDGE_CONTROL + 2,
        PCISWCAP_EXP_LIST_ID    = PCISWCAP + PCI_CAP_LIST_ID,
        PCISWCAP_EXP_DEVCAP     = PCISWCAP + PCI_EXP_DEVCAP,
        PCISWCAP_EXP_DEVCTL     = PCISWCAP + PCI_EXP_DEVCTL,
        PCISWCAP_EXP_LNKCAP     = PCISWCAP + PCI_EXP_LNKCAP,
        PCISWCAP_EXP_LNKCTL     = PCISWCAP + PCI_EXP_LNKCTL,
        PCISWCAP_EXP_SLTCAP     = PCISWCAP + PCI_EXP_SLTCAP,
        PCISWCAP_EXP_SLTCTL     = PCISWCAP + PCI_EXP_SLTCTL,
        PCISWCAP_EXP_RTCTL      = PCISWCAP + PCI_EXP_RTCTL,
        PCISWCAP_EXP_RTSTA      = PCISWCAP + PCI_EXP_RTSTA,
        PCISWCAP_EXP_DEVCAP2    = PCISWCAP + PCI_EXP_DEVCAP2,
        PCISWCAP_EXP_DEVCTL2    = PCISWCAP + PCI_EXP_DEVCTL2,
        PCISWCAP_EXP_LNKCAP2    = PCISWCAP + PCI_EXP_LNKCAP2,
        PCISWCAP_EXP_LNKCTL2    = PCISWCAP + PCI_EXP_LNKCTL2,
        PCISWCAP_EXP_SLTCAP2    = PCISWCAP + PCI_EXP_SLTCAP2,
        PCISWCAP_EXP_SLTCTL2    = PCISWCAP + PCI_EXP_SLTCTL2,
};

/* PCI configuration space of a PCI-to-PCI bridge */
struct mvebu_sw_pci_bridge {
        u16 vendor;
        u16 device;
        u16 command;
        u16 status;
        u16 class;
        u8 interface;
        u8 revision;
        u8 bist;
        u8 header_type;
        u8 latency_timer;
        u8 cache_line_size;
        u32 bar[2];
        u8 primary_bus;
        u8 secondary_bus;
        u8 subordinate_bus;
        u8 secondary_latency_timer;
        u8 iobase;
        u8 iolimit;
        u16 secondary_status;
        u16 membase;
        u16 memlimit;
        u16 iobaseupper;
        u16 iolimitupper;
        u32 romaddr;
        u8 intline;
        u8 intpin;
        u16 bridgectrl;

        /* PCI express capability */
        u32 pcie_sltcap;
        u16 pcie_devctl;
        u16 pcie_rtctl;
};

struct mvebu_pcie_port;

/* Structure representing all PCIe interfaces */
struct mvebu_pcie {
        struct platform_device *pdev;
        struct mvebu_pcie_port *ports;
        struct msi_controller *msi;
        struct resource io;
        struct resource realio;
        struct resource mem;
        struct resource busn;
        int nports;
};

/* Structure representing one PCIe interface */
struct mvebu_pcie_port {
        char *name;
        void __iomem *base;
        u32 port;
        u32 lane;
        int devfn;
        unsigned int mem_target;
        unsigned int mem_attr;
        unsigned int io_target;
        unsigned int io_attr;
        struct clk *clk;
        struct gpio_desc *reset_gpio;
        char *reset_name;
        struct mvebu_sw_pci_bridge bridge;
        struct device_node *dn;
        struct mvebu_pcie *pcie;
        phys_addr_t memwin_base;
        size_t memwin_size;
        phys_addr_t iowin_base;
        size_t iowin_size;
        u32 saved_pcie_stat;
};

static inline void mvebu_writel(struct mvebu_pcie_port *port, u32 val, u32 reg)
{
        writel(val, port->base + reg);
}

static inline u32 mvebu_readl(struct mvebu_pcie_port *port, u32 reg)
{
        return readl(port->base + reg);
}

static inline bool mvebu_has_ioport(struct mvebu_pcie_port *port)
{
        return port->io_target != -1 && port->io_attr != -1;
}

static bool mvebu_pcie_link_up(struct mvebu_pcie_port *port)
{
        return !(mvebu_readl(port, PCIE_STAT_OFF) & PCIE_STAT_LINK_DOWN);
}

static void mvebu_pcie_set_local_bus_nr(struct mvebu_pcie_port *port, int nr)
{
        u32 stat;

        stat = mvebu_readl(port, PCIE_STAT_OFF);
        stat &= ~PCIE_STAT_BUS;
        stat |= nr << 8;
        mvebu_writel(port, stat, PCIE_STAT_OFF);
}

static void mvebu_pcie_set_local_dev_nr(struct mvebu_pcie_port *port, int nr)
{
        u32 stat;

        stat = mvebu_readl(port, PCIE_STAT_OFF);
        stat &= ~PCIE_STAT_DEV;
        stat |= nr << 16;
        mvebu_writel(port, stat, PCIE_STAT_OFF);
}

/*
 * Setup PCIE BARs and Address Decode Wins:
 * BAR[0,2] -> disabled, BAR[1] -> covers all DRAM banks
 * WIN[0-3] -> DRAM bank[0-3]
 */
static void mvebu_pcie_setup_wins(struct mvebu_pcie_port *port)
{
        const struct mbus_dram_target_info *dram;
        u32 size;
        int i;

        dram = mv_mbus_dram_info();

        /* First, disable and clear BARs and windows. */
        for (i = 1; i < 3; i++) {
                mvebu_writel(port, 0, PCIE_BAR_CTRL_OFF(i));
                mvebu_writel(port, 0, PCIE_BAR_LO_OFF(i));
                mvebu_writel(port, 0, PCIE_BAR_HI_OFF(i));
        }

        for (i = 0; i < 5; i++) {
                mvebu_writel(port, 0, PCIE_WIN04_CTRL_OFF(i));
                mvebu_writel(port, 0, PCIE_WIN04_BASE_OFF(i));
                mvebu_writel(port, 0, PCIE_WIN04_REMAP_OFF(i));
        }

        mvebu_writel(port, 0, PCIE_WIN5_CTRL_OFF);
        mvebu_writel(port, 0, PCIE_WIN5_BASE_OFF);
        mvebu_writel(port, 0, PCIE_WIN5_REMAP_OFF);

        /* Setup windows for DDR banks.  Count total DDR size on the fly. */
        size = 0;
        for (i = 0; i < dram->num_cs; i++) {
                const struct mbus_dram_window *cs = dram->cs + i;

                mvebu_writel(port, cs->base & 0xffff0000,
                             PCIE_WIN04_BASE_OFF(i));
                mvebu_writel(port, 0, PCIE_WIN04_REMAP_OFF(i));
                mvebu_writel(port,
                             ((cs->size - 1) & 0xffff0000) |
                             (cs->mbus_attr << 8) |
                             (dram->mbus_dram_target_id << 4) | 1,
                             PCIE_WIN04_CTRL_OFF(i));

                size += cs->size;
        }

        /* Round up 'size' to the nearest power of two. */
        if ((size & (size - 1)) != 0)
                size = 1 << fls(size);

        /* Setup BAR[1] to all DRAM banks. */
        mvebu_writel(port, dram->cs[0].base, PCIE_BAR_LO_OFF(1));
        mvebu_writel(port, 0, PCIE_BAR_HI_OFF(1));
        mvebu_writel(port, ((size - 1) & 0xffff0000) | 1,
                     PCIE_BAR_CTRL_OFF(1));
}

static void mvebu_pcie_setup_hw(struct mvebu_pcie_port *port)
{
        u32 cmd, mask;

        /* Point PCIe unit MBUS decode windows to DRAM space. */
        mvebu_pcie_setup_wins(port);

        /* Master + slave enable. */
        cmd = mvebu_readl(port, PCIE_CMD_OFF);
        cmd |= PCI_COMMAND_IO;
        cmd |= PCI_COMMAND_MEMORY;
        cmd |= PCI_COMMAND_MASTER;
        mvebu_writel(port, cmd, PCIE_CMD_OFF);

        /* Enable interrupt lines A-D. */
        mask = mvebu_readl(port, PCIE_MASK_OFF);
        mask |= PCIE_MASK_ENABLE_INTS;
        mvebu_writel(port, mask, PCIE_MASK_OFF);
}

static int mvebu_pcie_hw_rd_conf(struct mvebu_pcie_port *port,
                                 struct pci_bus *bus,
                                 u32 devfn, int where, int size, u32 *val)
{
        void __iomem *conf_data = port->base + PCIE_CONF_DATA_OFF;

        mvebu_writel(port, PCIE_CONF_ADDR(bus->number, devfn, where),
                     PCIE_CONF_ADDR_OFF);

        switch (size) {
        case 1:
                *val = readb_relaxed(conf_data + (where & 3));
                break;
        case 2:
                *val = readw_relaxed(conf_data + (where & 2));
                break;
        case 4:
                *val = readl_relaxed(conf_data);
                break;
        }

        return PCIBIOS_SUCCESSFUL;
}

static int mvebu_pcie_hw_wr_conf(struct mvebu_pcie_port *port,
                                 struct pci_bus *bus,
                                 u32 devfn, int where, int size, u32 val)
{
        void __iomem *conf_data = port->base + PCIE_CONF_DATA_OFF;

        mvebu_writel(port, PCIE_CONF_ADDR(bus->number, devfn, where),
                     PCIE_CONF_ADDR_OFF);

        switch (size) {
        case 1:
                writeb(val, conf_data + (where & 3));
                break;
        case 2:
                writew(val, conf_data + (where & 2));
                break;
        case 4:
                writel(val, conf_data);
                break;
        default:
                return PCIBIOS_BAD_REGISTER_NUMBER;
        }

        return PCIBIOS_SUCCESSFUL;
}

/*
 * Remove windows, starting from the largest ones to the smallest
 * ones.
 */
static void mvebu_pcie_del_windows(struct mvebu_pcie_port *port,
                                   phys_addr_t base, size_t size)
{
        while (size) {
                size_t sz = 1 << (fls(size) - 1);

                mvebu_mbus_del_window(base, sz);
                base += sz;
                size -= sz;
        }
}

/*
 * MBus windows can only have a power of two size, but PCI BARs do not
 * have this constraint. Therefore, we have to split the PCI BAR into
 * areas each having a power of two size. We start from the largest
 * one (i.e highest order bit set in the size).
 */
static void mvebu_pcie_add_windows(struct mvebu_pcie_port *port,
                                   unsigned int target, unsigned int attribute,
                                   phys_addr_t base, size_t size,
                                   phys_addr_t remap)
{
        size_t size_mapped = 0;

        while (size) {
                size_t sz = 1 << (fls(size) - 1);
                int ret;

                ret = mvebu_mbus_add_window_remap_by_id(target, attribute, base,
                                                        sz, remap);
                if (ret) {
                        phys_addr_t end = base + sz - 1;

                        dev_err(&port->pcie->pdev->dev,
                                "Could not create MBus window at [mem %pa-%pa]: %d\n",
                                &base, &end, ret);
                        mvebu_pcie_del_windows(port, base - size_mapped,
                                               size_mapped);
                        return;
                }

                size -= sz;
                size_mapped += sz;
                base += sz;
                if (remap != MVEBU_MBUS_NO_REMAP)
                        remap += sz;
        }
}

static void mvebu_pcie_handle_iobase_change(struct mvebu_pcie_port *port)
{
        phys_addr_t iobase;

        /* Are the new iobase/iolimit values invalid? */
        if (port->bridge.iolimit < port->bridge.iobase ||
            port->bridge.iolimitupper < port->bridge.iobaseupper ||
            !(port->bridge.command & PCI_COMMAND_IO)) {

                /* If a window was configured, remove it */
                if (port->iowin_base) {
                        mvebu_pcie_del_windows(port, port->iowin_base,
                                               port->iowin_size);
                        port->iowin_base = 0;
                        port->iowin_size = 0;
                }

                return;
        }

        if (!mvebu_has_ioport(port)) {
                dev_WARN(&port->pcie->pdev->dev,
                         "Attempt to set IO when IO is disabled\n");
                return;
        }

        /*
         * We read the PCI-to-PCI bridge emulated registers, and
         * calculate the base address and size of the address decoding
         * window to setup, according to the PCI-to-PCI bridge
         * specifications. iobase is the bus address, port->iowin_base
         * is the CPU address.
         */
        iobase = ((port->bridge.iobase & 0xF0) << 8) |
                (port->bridge.iobaseupper << 16);
        port->iowin_base = port->pcie->io.start + iobase;
        port->iowin_size = ((0xFFF | ((port->bridge.iolimit & 0xF0) << 8) |
                            (port->bridge.iolimitupper << 16)) -
                            iobase) + 1;

        mvebu_pcie_add_windows(port, port->io_target, port->io_attr,
                               port->iowin_base, port->iowin_size,
                               iobase);
}

static void mvebu_pcie_handle_membase_change(struct mvebu_pcie_port *port)
{
        /* Are the new membase/memlimit values invalid? */
        if (port->bridge.memlimit < port->bridge.membase ||
            !(port->bridge.command & PCI_COMMAND_MEMORY)) {

                /* If a window was configured, remove it */
                if (port->memwin_base) {
                        mvebu_pcie_del_windows(port, port->memwin_base,
                                               port->memwin_size);
                        port->memwin_base = 0;
                        port->memwin_size = 0;
                }

                return;
        }

        /*
         * We read the PCI-to-PCI bridge emulated registers, and
         * calculate the base address and size of the address decoding
         * window to setup, according to the PCI-to-PCI bridge
         * specifications.
         */
        port->memwin_base  = ((port->bridge.membase & 0xFFF0) << 16);
        port->memwin_size  =
                (((port->bridge.memlimit & 0xFFF0) << 16) | 0xFFFFF) -
                port->memwin_base + 1;

        mvebu_pcie_add_windows(port, port->mem_target, port->mem_attr,
                               port->memwin_base, port->memwin_size,
                               MVEBU_MBUS_NO_REMAP);
}

/*
 * Initialize the configuration space of the PCI-to-PCI bridge
 * associated with the given PCIe interface.
 */
static void mvebu_sw_pci_bridge_init(struct mvebu_pcie_port *port)
{
        struct mvebu_sw_pci_bridge *bridge = &port->bridge;

        memset(bridge, 0, sizeof(struct mvebu_sw_pci_bridge));

        bridge->class = PCI_CLASS_BRIDGE_PCI;
        bridge->vendor = PCI_VENDOR_ID_MARVELL;
        bridge->device = mvebu_readl(port, PCIE_DEV_ID_OFF) >> 16;
        bridge->revision = mvebu_readl(port, PCIE_DEV_REV_OFF) & 0xff;
        bridge->header_type = PCI_HEADER_TYPE_BRIDGE;
        bridge->cache_line_size = 0x10;

        /* We support 32 bits I/O addressing */
        bridge->iobase = PCI_IO_RANGE_TYPE_32;
        bridge->iolimit = PCI_IO_RANGE_TYPE_32;

        /* Add capabilities */
        bridge->status = PCI_STATUS_CAP_LIST;
}

/*
 * Read the configuration space of the PCI-to-PCI bridge associated to
 * the given PCIe interface.
 */
static int mvebu_sw_pci_bridge_read(struct mvebu_pcie_port *port,
                                  unsigned int where, int size, u32 *value)
{
        struct mvebu_sw_pci_bridge *bridge = &port->bridge;

        switch (where & ~3) {
        case PCI_VENDOR_ID:
                *value = bridge->device << 16 | bridge->vendor;
                break;

        case PCI_COMMAND:
                *value = bridge->command | bridge->status << 16;
                break;

        case PCI_CLASS_REVISION:
                *value = bridge->class << 16 | bridge->interface << 8 |
                         bridge->revision;
                break;

        case PCI_CACHE_LINE_SIZE:
                *value = bridge->bist << 24 | bridge->header_type << 16 |
                         bridge->latency_timer << 8 | bridge->cache_line_size;
                break;

        case PCI_BASE_ADDRESS_0 ... PCI_BASE_ADDRESS_1:
                *value = bridge->bar[((where & ~3) - PCI_BASE_ADDRESS_0) / 4];
                break;

        case PCI_PRIMARY_BUS:
                *value = (bridge->secondary_latency_timer << 24 |
                          bridge->subordinate_bus         << 16 |
                          bridge->secondary_bus           <<  8 |
                          bridge->primary_bus);
                break;

        case PCI_IO_BASE:
                if (!mvebu_has_ioport(port))
                        *value = bridge->secondary_status << 16;
                else
                        *value = (bridge->secondary_status << 16 |
                                  bridge->iolimit          <<  8 |
                                  bridge->iobase);
                break;

        case PCI_MEMORY_BASE:
                *value = (bridge->memlimit << 16 | bridge->membase);
                break;

        case PCI_PREF_MEMORY_BASE:
                *value = 0;
                break;

        case PCI_IO_BASE_UPPER16:
                *value = (bridge->iolimitupper << 16 | bridge->iobaseupper);
                break;

        case PCI_CAPABILITY_LIST:
                *value = PCISWCAP;
                break;

        case PCI_ROM_ADDRESS1:
                *value = 0;
                break;

        case PCI_INTERRUPT_LINE:
                /* LINE PIN MIN_GNT MAX_LAT */
                *value = 0;
                break;

        case PCISWCAP_EXP_LIST_ID:
                /* Set PCIe v2, root port, slot support */
                *value = (PCI_EXP_TYPE_ROOT_PORT << 4 | 2 |
                          PCI_EXP_FLAGS_SLOT) << 16 | PCI_CAP_ID_EXP;
                break;

        case PCISWCAP_EXP_DEVCAP:
                *value = mvebu_readl(port, PCIE_CAP_PCIEXP + PCI_EXP_DEVCAP);
                break;

        case PCISWCAP_EXP_DEVCTL:
                *value = mvebu_readl(port, PCIE_CAP_PCIEXP + PCI_EXP_DEVCTL) &
                                 ~(PCI_EXP_DEVCTL_URRE | PCI_EXP_DEVCTL_FERE |
                                   PCI_EXP_DEVCTL_NFERE | PCI_EXP_DEVCTL_CERE);
                *value |= bridge->pcie_devctl;
                break;

        case PCISWCAP_EXP_LNKCAP:
                /*
                 * PCIe requires the clock power management capability to be
                 * hard-wired to zero for downstream ports
                 */
                *value = mvebu_readl(port, PCIE_CAP_PCIEXP + PCI_EXP_LNKCAP) &
                         ~PCI_EXP_LNKCAP_CLKPM;
                break;

        case PCISWCAP_EXP_LNKCTL:
                *value = mvebu_readl(port, PCIE_CAP_PCIEXP + PCI_EXP_LNKCTL);
                break;

        case PCISWCAP_EXP_SLTCAP:
                *value = bridge->pcie_sltcap;
                break;

        case PCISWCAP_EXP_SLTCTL:
                *value = PCI_EXP_SLTSTA_PDS << 16;
                break;

        case PCISWCAP_EXP_RTCTL:
                *value = bridge->pcie_rtctl;
                break;

        case PCISWCAP_EXP_RTSTA:
                *value = mvebu_readl(port, PCIE_RC_RTSTA);
                break;

        /* PCIe requires the v2 fields to be hard-wired to zero */
        case PCISWCAP_EXP_DEVCAP2:
        case PCISWCAP_EXP_DEVCTL2:
        case PCISWCAP_EXP_LNKCAP2:
        case PCISWCAP_EXP_LNKCTL2:
        case PCISWCAP_EXP_SLTCAP2:
        case PCISWCAP_EXP_SLTCTL2:
        default:
                /*
                 * PCI defines configuration read accesses to reserved or
                 * unimplemented registers to read as zero and complete
                 * normally.
                 */
                *value = 0;
                return PCIBIOS_SUCCESSFUL;
        }

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

        return PCIBIOS_SUCCESSFUL;
}

/* Write to the PCI-to-PCI bridge configuration space */
static int mvebu_sw_pci_bridge_write(struct mvebu_pcie_port *port,
                                     unsigned int where, int size, u32 value)
{
        struct mvebu_sw_pci_bridge *bridge = &port->bridge;
        u32 mask, reg;
        int err;

        if (size == 4)
                mask = 0x0;
        else if (size == 2)
                mask = ~(0xffff << ((where & 3) * 8));
        else if (size == 1)
                mask = ~(0xff << ((where & 3) * 8));
        else
                return PCIBIOS_BAD_REGISTER_NUMBER;

        err = mvebu_sw_pci_bridge_read(port, where & ~3, 4, &reg);
        if (err)
                return err;

        value = (reg & mask) | value << ((where & 3) * 8);

        switch (where & ~3) {
        case PCI_COMMAND:
        {
                u32 old = bridge->command;

                if (!mvebu_has_ioport(port))
                        value &= ~PCI_COMMAND_IO;

                bridge->command = value & 0xffff;
                if ((old ^ bridge->command) & PCI_COMMAND_IO)
                        mvebu_pcie_handle_iobase_change(port);
                if ((old ^ bridge->command) & PCI_COMMAND_MEMORY)
                        mvebu_pcie_handle_membase_change(port);
                break;
        }

        case PCI_BASE_ADDRESS_0 ... PCI_BASE_ADDRESS_1:
                bridge->bar[((where & ~3) - PCI_BASE_ADDRESS_0) / 4] = value;
                break;

        case PCI_IO_BASE:
                /*
                 * We also keep bit 1 set, it is a read-only bit that
                 * indicates we support 32 bits addressing for the
                 * I/O
                 */
                bridge->iobase = (value & 0xff) | PCI_IO_RANGE_TYPE_32;
                bridge->iolimit = ((value >> 8) & 0xff) | PCI_IO_RANGE_TYPE_32;
                mvebu_pcie_handle_iobase_change(port);
                break;

        case PCI_MEMORY_BASE:
                bridge->membase = value & 0xffff;
                bridge->memlimit = value >> 16;
                mvebu_pcie_handle_membase_change(port);
                break;

        case PCI_IO_BASE_UPPER16:
                bridge->iobaseupper = value & 0xffff;
                bridge->iolimitupper = value >> 16;
                mvebu_pcie_handle_iobase_change(port);
                break;

        case PCI_PRIMARY_BUS:
                bridge->primary_bus             = value & 0xff;
                bridge->secondary_bus           = (value >> 8) & 0xff;
                bridge->subordinate_bus         = (value >> 16) & 0xff;
                bridge->secondary_latency_timer = (value >> 24) & 0xff;
                mvebu_pcie_set_local_bus_nr(port, bridge->secondary_bus);
                break;

        case PCISWCAP_EXP_DEVCTL:
                /*
                 * Armada370 data says these bits must always
                 * be zero when in root complex mode.
                 */
                value &= ~(PCI_EXP_DEVCTL_URRE | PCI_EXP_DEVCTL_FERE |
                           PCI_EXP_DEVCTL_NFERE | PCI_EXP_DEVCTL_CERE);

                /*
                 * If the mask is 0xffff0000, then we only want to write
                 * the device control register, rather than clearing the
                 * RW1C bits in the device status register.  Mask out the
                 * status register bits.
                 */
                if (mask == 0xffff0000)
                        value &= 0xffff;

                mvebu_writel(port, value, PCIE_CAP_PCIEXP + PCI_EXP_DEVCTL);
                break;

        case PCISWCAP_EXP_LNKCTL:
                /*
                 * If we don't support CLKREQ, we must ensure that the
                 * CLKREQ enable bit always reads zero.  Since we haven't
                 * had this capability, and it's dependent on board wiring,
                 * disable it for the time being.
                 */
                value &= ~PCI_EXP_LNKCTL_CLKREQ_EN;

                /*
                 * If the mask is 0xffff0000, then we only want to write
                 * the link control register, rather than clearing the
                 * RW1C bits in the link status register.  Mask out the
                 * status register bits.
                 */
                if (mask == 0xffff0000)
                        value &= 0xffff;

                mvebu_writel(port, value, PCIE_CAP_PCIEXP + PCI_EXP_LNKCTL);
                break;

        case PCISWCAP_EXP_RTSTA:
                mvebu_writel(port, value, PCIE_RC_RTSTA);
                break;

        default:
                break;
        }

        return PCIBIOS_SUCCESSFUL;
}

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

static struct mvebu_pcie_port *mvebu_pcie_find_port(struct mvebu_pcie *pcie,
                                                    struct pci_bus *bus,
                                                    int devfn)
{
        int i;

        for (i = 0; i < pcie->nports; i++) {
                struct mvebu_pcie_port *port = &pcie->ports[i];

                if (bus->number == 0 && port->devfn == devfn)
                        return port;
                if (bus->number != 0 &&
                    bus->number >= port->bridge.secondary_bus &&
                    bus->number <= port->bridge.subordinate_bus)
                        return port;
        }

        return NULL;
}

/* PCI configuration space write function */
static int mvebu_pcie_wr_conf(struct pci_bus *bus, u32 devfn,
                              int where, int size, u32 val)
{
        struct mvebu_pcie *pcie = sys_to_pcie(bus->sysdata);
        struct mvebu_pcie_port *port;
        int ret;

        port = mvebu_pcie_find_port(pcie, bus, devfn);
        if (!port)
                return PCIBIOS_DEVICE_NOT_FOUND;

        /* Access the emulated PCI-to-PCI bridge */
        if (bus->number == 0)
                return mvebu_sw_pci_bridge_write(port, where, size, val);

        if (!mvebu_pcie_link_up(port))
                return PCIBIOS_DEVICE_NOT_FOUND;

        /* Access the real PCIe interface */
        ret = mvebu_pcie_hw_wr_conf(port, bus, devfn,
                                    where, size, val);

        return ret;
}

/* PCI configuration space read function */
static int mvebu_pcie_rd_conf(struct pci_bus *bus, u32 devfn, int where,
                              int size, u32 *val)
{
        struct mvebu_pcie *pcie = sys_to_pcie(bus->sysdata);
        struct mvebu_pcie_port *port;
        int ret;

        port = mvebu_pcie_find_port(pcie, bus, devfn);
        if (!port) {
                *val = 0xffffffff;
                return PCIBIOS_DEVICE_NOT_FOUND;
        }

        /* Access the emulated PCI-to-PCI bridge */
        if (bus->number == 0)
                return mvebu_sw_pci_bridge_read(port, where, size, val);

        if (!mvebu_pcie_link_up(port)) {
                *val = 0xffffffff;
                return PCIBIOS_DEVICE_NOT_FOUND;
        }

        /* Access the real PCIe interface */
        ret = mvebu_pcie_hw_rd_conf(port, bus, devfn,
                                    where, size, val);

        return ret;
}

static struct pci_ops mvebu_pcie_ops = {
        .read = mvebu_pcie_rd_conf,
        .write = mvebu_pcie_wr_conf,
};

static int mvebu_pcie_setup(int nr, struct pci_sys_data *sys)
{
        struct mvebu_pcie *pcie = sys_to_pcie(sys);
        int err, i;

        pcie->mem.name = "PCI MEM";
        pcie->realio.name = "PCI I/O";

        if (resource_size(&pcie->realio) != 0)
                pci_add_resource_offset(&sys->resources, &pcie->realio,
                                        sys->io_offset);

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

        err = devm_request_pci_bus_resources(&pcie->pdev->dev, &sys->resources);
        if (err)
                return 0;

        for (i = 0; i < pcie->nports; i++) {
                struct mvebu_pcie_port *port = &pcie->ports[i];

                if (!port->base)
                        continue;
                mvebu_pcie_setup_hw(port);
        }

        return 1;
}

static resource_size_t mvebu_pcie_align_resource(struct pci_dev *dev,
                                                 const struct resource *res,
                                                 resource_size_t start,
                                                 resource_size_t size,
                                                 resource_size_t align)
{
        if (dev->bus->number != 0)
                return start;

        /*
         * On the PCI-to-PCI bridge side, the I/O windows must have at
         * least a 64 KB size and the memory windows must have at
         * least a 1 MB size. Moreover, MBus windows need to have a
         * base address aligned on their size, and their size must be
         * a power of two. This means that if the BAR doesn't have a
         * power of two size, several MBus windows will actually be
         * created. We need to ensure that the biggest MBus window
         * (which will be the first one) is aligned on its size, which
         * explains the rounddown_pow_of_two() being done here.
         */
        if (res->flags & IORESOURCE_IO)
                return round_up(start, max_t(resource_size_t, SZ_64K,
                                             rounddown_pow_of_two(size)));
        else if (res->flags & IORESOURCE_MEM)
                return round_up(start, max_t(resource_size_t, SZ_1M,
                                             rounddown_pow_of_two(size)));
        else
                return start;
}

static void mvebu_pcie_enable(struct mvebu_pcie *pcie)
{
        struct hw_pci hw;

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

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

        hw.nr_controllers = 1;
        hw.private_data   = (void **)&pcie;
        hw.setup          = mvebu_pcie_setup;
        hw.map_irq        = of_irq_parse_and_map_pci;
        hw.ops            = &mvebu_pcie_ops;
        hw.align_resource = mvebu_pcie_align_resource;

        pci_common_init_dev(&pcie->pdev->dev, &hw);
}

/*
 * Looks up the list of register addresses encoded into the reg =
 * <...> property for one that matches the given port/lane. Once
 * found, maps it.
 */
static void __iomem *mvebu_pcie_map_registers(struct platform_device *pdev,
                                              struct device_node *np,
                                              struct mvebu_pcie_port *port)
{
        struct resource regs;
        int ret = 0;

        ret = of_address_to_resource(np, 0, &regs);
        if (ret)
                return ERR_PTR(ret);

        return devm_ioremap_resource(&pdev->dev, &regs);
}

#define DT_FLAGS_TO_TYPE(flags)       (((flags) >> 24) & 0x03)
#define    DT_TYPE_IO                 0x1
#define    DT_TYPE_MEM32              0x2
#define DT_CPUADDR_TO_TARGET(cpuaddr) (((cpuaddr) >> 56) & 0xFF)
#define DT_CPUADDR_TO_ATTR(cpuaddr)   (((cpuaddr) >> 48) & 0xFF)

static int mvebu_get_tgt_attr(struct device_node *np, int devfn,
                              unsigned long type,
                              unsigned int *tgt,
                              unsigned int *attr)
{
        const int na = 3, ns = 2;
        const __be32 *range;
        int rlen, nranges, rangesz, pna, i;

        *tgt = -1;
        *attr = -1;

        range = of_get_property(np, "ranges", &rlen);
        if (!range)
                return -EINVAL;

        pna = of_n_addr_cells(np);
        rangesz = pna + na + ns;
        nranges = rlen / sizeof(__be32) / rangesz;

        for (i = 0; i < nranges; i++, range += rangesz) {
                u32 flags = of_read_number(range, 1);
                u32 slot = of_read_number(range + 1, 1);
                u64 cpuaddr = of_read_number(range + na, pna);
                unsigned long rtype;

                if (DT_FLAGS_TO_TYPE(flags) == DT_TYPE_IO)
                        rtype = IORESOURCE_IO;
                else if (DT_FLAGS_TO_TYPE(flags) == DT_TYPE_MEM32)
                        rtype = IORESOURCE_MEM;
                else
                        continue;

                if (slot == PCI_SLOT(devfn) && type == rtype) {
                        *tgt = DT_CPUADDR_TO_TARGET(cpuaddr);
                        *attr = DT_CPUADDR_TO_ATTR(cpuaddr);
                        return 0;
                }
        }

        return -ENOENT;
}

static void mvebu_pcie_msi_enable(struct mvebu_pcie *pcie)
{
        struct device_node *msi_node;

        msi_node = of_parse_phandle(pcie->pdev->dev.of_node,
                                    "msi-parent", 0);
        if (!msi_node)
                return;

        pcie->msi = of_pci_find_msi_chip_by_node(msi_node);
        of_node_put(msi_node);

        if (pcie->msi)
                pcie->msi->dev = &pcie->pdev->dev;
}

#ifdef CONFIG_PM_SLEEP
static int mvebu_pcie_suspend(struct device *dev)
{
        struct mvebu_pcie *pcie;
        int i;

        pcie = dev_get_drvdata(dev);
        for (i = 0; i < pcie->nports; i++) {
                struct mvebu_pcie_port *port = pcie->ports + i;
                port->saved_pcie_stat = mvebu_readl(port, PCIE_STAT_OFF);
        }

        return 0;
}

static int mvebu_pcie_resume(struct device *dev)
{
        struct mvebu_pcie *pcie;
        int i;

        pcie = dev_get_drvdata(dev);
        for (i = 0; i < pcie->nports; i++) {
                struct mvebu_pcie_port *port = pcie->ports + i;
                mvebu_writel(port, port->saved_pcie_stat, PCIE_STAT_OFF);
                mvebu_pcie_setup_hw(port);
        }

        return 0;
}
#endif

static void mvebu_pcie_port_clk_put(void *data)
{
        struct mvebu_pcie_port *port = data;

        clk_put(port->clk);
}

static int mvebu_pcie_parse_port(struct mvebu_pcie *pcie,
        struct mvebu_pcie_port *port, struct device_node *child)
{
        struct device *dev = &pcie->pdev->dev;
        enum of_gpio_flags flags;
        int reset_gpio, ret;

        port->pcie = pcie;

        if (of_property_read_u32(child, "marvell,pcie-port", &port->port)) {
                dev_warn(dev, "ignoring %s, missing pcie-port property\n",
                         of_node_full_name(child));
                goto skip;
        }

        if (of_property_read_u32(child, "marvell,pcie-lane", &port->lane))
                port->lane = 0;

        port->name = devm_kasprintf(dev, GFP_KERNEL, "pcie%d.%d", port->port,
                                    port->lane);
        if (!port->name) {
                ret = -ENOMEM;
                goto err;
        }

        port->devfn = of_pci_get_devfn(child);
        if (port->devfn < 0)
                goto skip;

        ret = mvebu_get_tgt_attr(dev->of_node, port->devfn, IORESOURCE_MEM,
                                 &port->mem_target, &port->mem_attr);
        if (ret < 0) {
                dev_err(dev, "%s: cannot get tgt/attr for mem window\n",
                        port->name);
                goto skip;
        }

        if (resource_size(&pcie->io) != 0) {
                mvebu_get_tgt_attr(dev->of_node, port->devfn, IORESOURCE_IO,
                                   &port->io_target, &port->io_attr);
        } else {
                port->io_target = -1;
                port->io_attr = -1;
        }

        reset_gpio = of_get_named_gpio_flags(child, "reset-gpios", 0, &flags);
        if (reset_gpio == -EPROBE_DEFER) {
                ret = reset_gpio;
                goto err;
        }

        if (gpio_is_valid(reset_gpio)) {
                unsigned long gpio_flags;

                port->reset_name = devm_kasprintf(dev, GFP_KERNEL, "%s-reset",
                                                  port->name);
                if (!port->reset_name) {
                        ret = -ENOMEM;
                        goto err;
                }

                if (flags & OF_GPIO_ACTIVE_LOW) {
                        dev_info(dev, "%s: reset gpio is active low\n",
                                 of_node_full_name(child));
                        gpio_flags = GPIOF_ACTIVE_LOW |
                                     GPIOF_OUT_INIT_LOW;
                } else {
                        gpio_flags = GPIOF_OUT_INIT_HIGH;
                }

                ret = devm_gpio_request_one(dev, reset_gpio, gpio_flags,
                                            port->reset_name);
                if (ret) {
                        if (ret == -EPROBE_DEFER)
                                goto err;
                        goto skip;
                }

                port->reset_gpio = gpio_to_desc(reset_gpio);
        }

        port->clk = of_clk_get_by_name(child, NULL);
        if (IS_ERR(port->clk)) {
                dev_err(dev, "%s: cannot get clock\n", port->name);
                goto skip;
        }

        ret = devm_add_action(dev, mvebu_pcie_port_clk_put, port);
        if (ret < 0) {
                clk_put(port->clk);
                goto err;
        }

        return 1;

skip:
        ret = 0;

        /* In the case of skipping, we need to free these */
        devm_kfree(dev, port->reset_name);
        port->reset_name = NULL;
        devm_kfree(dev, port->name);
        port->name = NULL;

err:
        return ret;
}

/*
 * Power up a PCIe port.  PCIe requires the refclk to be stable for 100µs
 * prior to releasing PERST.  See table 2-4 in section 2.6.2 AC Specifications
 * of the PCI Express Card Electromechanical Specification, 1.1.
 */
static int mvebu_pcie_powerup(struct mvebu_pcie_port *port)
{
        int ret;

        ret = clk_prepare_enable(port->clk);
        if (ret < 0)
                return ret;

        if (port->reset_gpio) {
                u32 reset_udelay = 20000;

                of_property_read_u32(port->dn, "reset-delay-us",
                                     &reset_udelay);

                udelay(100);

                gpiod_set_value_cansleep(port->reset_gpio, 0);
                msleep(reset_udelay / 1000);
        }

        return 0;
}

/*
 * Power down a PCIe port.  Strictly, PCIe requires us to place the card
 * in D3hot state before asserting PERST#.
 */
static void mvebu_pcie_powerdown(struct mvebu_pcie_port *port)
{
        if (port->reset_gpio)
                gpiod_set_value_cansleep(port->reset_gpio, 1);

        clk_disable_unprepare(port->clk);
}

static int mvebu_pcie_probe(struct platform_device *pdev)
{
        struct mvebu_pcie *pcie;
        struct device_node *np = pdev->dev.of_node;
        struct device_node *child;
        int num, i, ret;

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

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

        /* Get the PCIe memory and I/O aperture */
        mvebu_mbus_get_pcie_mem_aperture(&pcie->mem);
        if (resource_size(&pcie->mem) == 0) {
                dev_err(&pdev->dev, "invalid memory aperture size\n");
                return -EINVAL;
        }

        mvebu_mbus_get_pcie_io_aperture(&pcie->io);

        if (resource_size(&pcie->io) != 0) {
                pcie->realio.flags = pcie->io.flags;
                pcie->realio.start = PCIBIOS_MIN_IO;
                pcie->realio.end = min_t(resource_size_t,
                                         IO_SPACE_LIMIT,
                                         resource_size(&pcie->io));
        } else
                pcie->realio = pcie->io;

        /* Get the bus range */
        ret = of_pci_parse_bus_range(np, &pcie->busn);
        if (ret) {
                dev_err(&pdev->dev, "failed to parse bus-range property: %d\n",
                        ret);
                return ret;
        }

        num = of_get_available_child_count(pdev->dev.of_node);

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

        i = 0;
        for_each_available_child_of_node(pdev->dev.of_node, child) {
                struct mvebu_pcie_port *port = &pcie->ports[i];

                ret = mvebu_pcie_parse_port(pcie, port, child);
                if (ret < 0) {
                        of_node_put(child);
                        return ret;
                } else if (ret == 0) {
                        continue;
                }

                port->dn = child;
                i++;
        }
        pcie->nports = i;

        for (i = 0; i < pcie->nports; i++) {
                struct mvebu_pcie_port *port = &pcie->ports[i];

                child = port->dn;
                if (!child)
                        continue;

                ret = mvebu_pcie_powerup(port);
                if (ret < 0)
                        continue;

                port->base = mvebu_pcie_map_registers(pdev, child, port);
                if (IS_ERR(port->base)) {
                        dev_err(&pdev->dev, "%s: cannot map registers\n",
                                port->name);
                        port->base = NULL;
                        mvebu_pcie_powerdown(port);
                        continue;
                }

                mvebu_pcie_set_local_dev_nr(port, 1);
                mvebu_sw_pci_bridge_init(port);
        }

        pcie->nports = i;

        for (i = 0; i < (IO_SPACE_LIMIT - SZ_64K); i += SZ_64K)
                pci_ioremap_io(i, pcie->io.start + i);

        mvebu_pcie_msi_enable(pcie);
        mvebu_pcie_enable(pcie);

        platform_set_drvdata(pdev, pcie);

        return 0;
}

static const struct of_device_id mvebu_pcie_of_match_table[] = {
        { .compatible = "marvell,armada-xp-pcie", },
        { .compatible = "marvell,armada-370-pcie", },
        { .compatible = "marvell,dove-pcie", },
        { .compatible = "marvell,kirkwood-pcie", },
        {},
};

static const struct dev_pm_ops mvebu_pcie_pm_ops = {
        SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(mvebu_pcie_suspend, mvebu_pcie_resume)
};

static struct platform_driver mvebu_pcie_driver = {
        .driver = {
                .name = "mvebu-pcie",
                .of_match_table = mvebu_pcie_of_match_table,
                /* driver unloading/unbinding currently not supported */
                .suppress_bind_attrs = true,
                .pm = &mvebu_pcie_pm_ops,
        },
        .probe = mvebu_pcie_probe,
};
builtin_platform_driver(mvebu_pcie_driver);