// SPDX-License-Identifier: GPL-2.0
/*
 * PCIe driver for Renesas R-Car SoCs
 *  Copyright (C) 2014 Renesas Electronics Europe Ltd
 *
 * Based on:
 *  arch/sh/drivers/pci/pcie-sh7786.c
 *  arch/sh/drivers/pci/ops-sh7786.c
 *  Copyright (C) 2009 - 2011  Paul Mundt
 *
 * Author: Phil Edworthy <phil.edworthy@renesas.com>
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/msi.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_pci.h>
#include <linux/of_platform.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>

#define PCIECAR                 0x000010
#define PCIECCTLR               0x000018
#define  CONFIG_SEND_ENABLE     (1 << 31)
#define  TYPE0                  (0 << 8)
#define  TYPE1                  (1 << 8)
#define PCIECDR                 0x000020
#define PCIEMSR                 0x000028
#define PCIEINTXR               0x000400
#define PCIEMSITXR              0x000840

/* Transfer control */
#define PCIETCTLR               0x02000
#define  CFINIT                 1
#define PCIETSTR                0x02004
#define  DATA_LINK_ACTIVE       1
#define PCIEERRFR               0x02020
#define  UNSUPPORTED_REQUEST    (1 << 4)
#define PCIEMSIFR               0x02044
#define PCIEMSIALR              0x02048
#define  MSIFE                  1
#define PCIEMSIAUR              0x0204c
#define PCIEMSIIER              0x02050

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

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

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

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

/* link layer */
#define IDSETR1                 0x011004
#define TLCTLR                  0x011048
#define MACSR                   0x011054
#define  SPCHGFIN               (1 << 4)
#define  SPCHGFAIL              (1 << 6)
#define  SPCHGSUC               (1 << 7)
#define  LINK_SPEED             (0xf << 16)
#define  LINK_SPEED_2_5GTS      (1 << 16)
#define  LINK_SPEED_5_0GTS      (2 << 16)
#define MACCTLR                 0x011058
#define  SPEED_CHANGE           (1 << 24)
#define  SCRAMBLE_DISABLE       (1 << 27)
#define MACS2R                  0x011078
#define MACCGSPSETR             0x011084
#define  SPCNGRSN               (1 << 31)

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

/* R-Car Gen2 PHY */
#define GEN2_PCIEPHYADDR        0x780
#define GEN2_PCIEPHYDATA        0x784
#define GEN2_PCIEPHYCTRL        0x78c

#define INT_PCI_MSI_NR  32

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

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

#define RCAR_PCI_MAX_RESOURCES 4
#define MAX_NR_INBOUND_MAPS 6

struct rcar_msi {
        DECLARE_BITMAP(used, INT_PCI_MSI_NR);
        struct irq_domain *domain;
        struct msi_controller chip;
        unsigned long pages;
        struct mutex lock;
        int irq1;
        int irq2;
};

static inline struct rcar_msi *to_rcar_msi(struct msi_controller *chip)
{
        return container_of(chip, struct rcar_msi, chip);
}

/* Structure representing the PCIe interface */
struct rcar_pcie {
        struct device           *dev;
        void __iomem            *base;
        struct list_head        resources;
        int                     root_bus_nr;
        struct clk              *clk;
        struct clk              *bus_clk;
        struct                  rcar_msi msi;
};

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

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

enum {
        RCAR_PCI_ACCESS_READ,
        RCAR_PCI_ACCESS_WRITE,
};

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

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

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

        return val >> shift;
}

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

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

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

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

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

                return PCIBIOS_SUCCESSFUL;
        }

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

        /* Clear errors */
        rcar_pci_write_reg(pcie, rcar_pci_read_reg(pcie, PCIEERRFR), PCIEERRFR);

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

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

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

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

        if (access_type == RCAR_PCI_ACCESS_READ)
                *data = rcar_pci_read_reg(pcie, PCIECDR);
        else
                rcar_pci_write_reg(pcie, *data, PCIECDR);

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

        return PCIBIOS_SUCCESSFUL;
}

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

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

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

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

        return ret;
}

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

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

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

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

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

        return ret;
}

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

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

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

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

        if (res->flags & IORESOURCE_IO)
                res_start = pci_pio_to_address(res->start);
        else
                res_start = res->start;

        rcar_pci_write_reg(pcie, upper_32_bits(res_start), PCIEPAUR(win));
        rcar_pci_write_reg(pcie, lower_32_bits(res_start) & ~0x7F,
                           PCIEPALR(win));

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

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

static int rcar_pcie_setup(struct list_head *resource, struct rcar_pcie *pci)
{
        struct resource_entry *win;
        int i = 0;

        /* Setup PCI resources */
        resource_list_for_each_entry(win, &pci->resources) {
                struct resource *res = win->res;

                if (!res->flags)
                        continue;

                switch (resource_type(res)) {
                case IORESOURCE_IO:
                case IORESOURCE_MEM:
                        rcar_pcie_setup_window(i, pci, res);
                        i++;
                        break;
                case IORESOURCE_BUS:
                        pci->root_bus_nr = res->start;
                        break;
                default:
                        continue;
                }

                pci_add_resource(resource, res);
        }

        return 1;
}

static void rcar_pcie_force_speedup(struct rcar_pcie *pcie)
{
        struct device *dev = pcie->dev;
        unsigned int timeout = 1000;
        u32 macsr;

        if ((rcar_pci_read_reg(pcie, MACS2R) & LINK_SPEED) != LINK_SPEED_5_0GTS)
                return;

        if (rcar_pci_read_reg(pcie, MACCTLR) & SPEED_CHANGE) {
                dev_err(dev, "Speed change already in progress\n");
                return;
        }

        macsr = rcar_pci_read_reg(pcie, MACSR);
        if ((macsr & LINK_SPEED) == LINK_SPEED_5_0GTS)
                goto done;

        /* Set target link speed to 5.0 GT/s */
        rcar_rmw32(pcie, EXPCAP(12), PCI_EXP_LNKSTA_CLS,
                   PCI_EXP_LNKSTA_CLS_5_0GB);

        /* Set speed change reason as intentional factor */
        rcar_rmw32(pcie, MACCGSPSETR, SPCNGRSN, 0);

        /* Clear SPCHGFIN, SPCHGSUC, and SPCHGFAIL */
        if (macsr & (SPCHGFIN | SPCHGSUC | SPCHGFAIL))
                rcar_pci_write_reg(pcie, macsr, MACSR);

        /* Start link speed change */
        rcar_rmw32(pcie, MACCTLR, SPEED_CHANGE, SPEED_CHANGE);

        while (timeout--) {
                macsr = rcar_pci_read_reg(pcie, MACSR);
                if (macsr & SPCHGFIN) {
                        /* Clear the interrupt bits */
                        rcar_pci_write_reg(pcie, macsr, MACSR);

                        if (macsr & SPCHGFAIL)
                                dev_err(dev, "Speed change failed\n");

                        goto done;
                }

                msleep(1);
        }

        dev_err(dev, "Speed change timed out\n");

done:
        dev_info(dev, "Current link speed is %s GT/s\n",
                 (macsr & LINK_SPEED) == LINK_SPEED_5_0GTS ? "5" : "2.5");
}

static int rcar_pcie_enable(struct rcar_pcie *pcie)
{
        struct device *dev = pcie->dev;
        struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
        struct pci_bus *bus, *child;
        int ret;

        /* Try setting 5 GT/s link speed */
        rcar_pcie_force_speedup(pcie);

        rcar_pcie_setup(&bridge->windows, pcie);

        pci_add_flags(PCI_REASSIGN_ALL_BUS);

        bridge->dev.parent = dev;
        bridge->sysdata = pcie;
        bridge->busnr = pcie->root_bus_nr;
        bridge->ops = &rcar_pcie_ops;
        bridge->map_irq = of_irq_parse_and_map_pci;
        bridge->swizzle_irq = pci_common_swizzle;
        if (IS_ENABLED(CONFIG_PCI_MSI))
                bridge->msi = &pcie->msi.chip;

        ret = pci_scan_root_bus_bridge(bridge);
        if (ret < 0)
                return ret;

        bus = bridge->bus;

        pci_bus_size_bridges(bus);
        pci_bus_assign_resources(bus);

        list_for_each_entry(child, &bus->children, node)
                pcie_bus_configure_settings(child);

        pci_bus_add_devices(bus);

        return 0;
}

static int phy_wait_for_ack(struct rcar_pcie *pcie)
{
        struct device *dev = pcie->dev;
        unsigned int timeout = 100;

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

                udelay(100);
        }

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

        return -ETIMEDOUT;
}

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

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

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

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

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

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

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

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

                msleep(5);
        }

        return -ETIMEDOUT;
}

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

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

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

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

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

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

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

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

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

        /* Terminate list of capabilities (Next Capability Offset=0) */
        rcar_rmw32(pcie, RVCCAP(0), 0xfff00000, 0);

        /* Enable MSI */
        if (IS_ENABLED(CONFIG_PCI_MSI))
                rcar_pci_write_reg(pcie, 0x801f0000, PCIEMSITXR);

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

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

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

        wmb();

        return 0;
}

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

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

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

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

                msleep(5);
        }

        return -ETIMEDOUT;
}

static int rcar_pcie_hw_init_gen2(struct rcar_pcie *pcie)
{
        /*
         * These settings come from the R-Car Series, 2nd Generation User's
         * Manual, section 50.3.1 (2) Initialization of the physical layer.
         */
        rcar_pci_write_reg(pcie, 0x000f0030, GEN2_PCIEPHYADDR);
        rcar_pci_write_reg(pcie, 0x00381203, GEN2_PCIEPHYDATA);
        rcar_pci_write_reg(pcie, 0x00000001, GEN2_PCIEPHYCTRL);
        rcar_pci_write_reg(pcie, 0x00000006, GEN2_PCIEPHYCTRL);

        rcar_pci_write_reg(pcie, 0x000f0054, GEN2_PCIEPHYADDR);
        /* The following value is for DC connection, no termination resistor */
        rcar_pci_write_reg(pcie, 0x13802007, GEN2_PCIEPHYDATA);
        rcar_pci_write_reg(pcie, 0x00000001, GEN2_PCIEPHYCTRL);
        rcar_pci_write_reg(pcie, 0x00000006, GEN2_PCIEPHYCTRL);

        return rcar_pcie_hw_init(pcie);
}

static int rcar_msi_alloc(struct rcar_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 int rcar_msi_alloc_region(struct rcar_msi *chip, int no_irqs)
{
        int msi;

        mutex_lock(&chip->lock);
        msi = bitmap_find_free_region(chip->used, INT_PCI_MSI_NR,
                                      order_base_2(no_irqs));
        mutex_unlock(&chip->lock);

        return msi;
}

static void rcar_msi_free(struct rcar_msi *chip, unsigned long irq)
{
        mutex_lock(&chip->lock);
        clear_bit(irq, chip->used);
        mutex_unlock(&chip->lock);
}

static irqreturn_t rcar_pcie_msi_irq(int irq, void *data)
{
        struct rcar_pcie *pcie = data;
        struct rcar_msi *msi = &pcie->msi;
        struct device *dev = pcie->dev;
        unsigned long reg;

        reg = rcar_pci_read_reg(pcie, PCIEMSIFR);

        /* MSI & INTx share an interrupt - we only handle MSI here */
        if (!reg)
                return IRQ_NONE;

        while (reg) {
                unsigned int index = find_first_bit(&reg, 32);
                unsigned int irq;

                /* clear the interrupt */
                rcar_pci_write_reg(pcie, 1 << index, PCIEMSIFR);

                irq = irq_find_mapping(msi->domain, index);
                if (irq) {
                        if (test_bit(index, msi->used))
                                generic_handle_irq(irq);
                        else
                                dev_info(dev, "unhandled MSI\n");
                } else {
                        /* Unknown MSI, just clear it */
                        dev_dbg(dev, "unexpected MSI\n");
                }

                /* see if there's any more pending in this vector */
                reg = rcar_pci_read_reg(pcie, PCIEMSIFR);
        }

        return IRQ_HANDLED;
}

static int rcar_msi_setup_irq(struct msi_controller *chip, struct pci_dev *pdev,
                              struct msi_desc *desc)
{
        struct rcar_msi *msi = to_rcar_msi(chip);
        struct rcar_pcie *pcie = container_of(chip, struct rcar_pcie, msi.chip);
        struct msi_msg msg;
        unsigned int irq;
        int hwirq;

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

        irq = irq_find_mapping(msi->domain, hwirq);
        if (!irq) {
                rcar_msi_free(msi, hwirq);
                return -EINVAL;
        }

        irq_set_msi_desc(irq, desc);

        msg.address_lo = rcar_pci_read_reg(pcie, PCIEMSIALR) & ~MSIFE;
        msg.address_hi = rcar_pci_read_reg(pcie, PCIEMSIAUR);
        msg.data = hwirq;

        pci_write_msi_msg(irq, &msg);

        return 0;
}

static int rcar_msi_setup_irqs(struct msi_controller *chip,
                               struct pci_dev *pdev, int nvec, int type)
{
        struct rcar_pcie *pcie = container_of(chip, struct rcar_pcie, msi.chip);
        struct rcar_msi *msi = to_rcar_msi(chip);
        struct msi_desc *desc;
        struct msi_msg msg;
        unsigned int irq;
        int hwirq;
        int i;

        /* MSI-X interrupts are not supported */
        if (type == PCI_CAP_ID_MSIX)
                return -EINVAL;

        WARN_ON(!list_is_singular(&pdev->dev.msi_list));
        desc = list_entry(pdev->dev.msi_list.next, struct msi_desc, list);

        hwirq = rcar_msi_alloc_region(msi, nvec);
        if (hwirq < 0)
                return -ENOSPC;

        irq = irq_find_mapping(msi->domain, hwirq);
        if (!irq)
                return -ENOSPC;

        for (i = 0; i < nvec; i++) {
                /*
                 * irq_create_mapping() called from rcar_pcie_probe() pre-
                 * allocates descs,  so there is no need to allocate descs here.
                 * We can therefore assume that if irq_find_mapping() above
                 * returns non-zero, then the descs are also successfully
                 * allocated.
                 */
                if (irq_set_msi_desc_off(irq, i, desc)) {
                        /* TODO: clear */
                        return -EINVAL;
                }
        }

        desc->nvec_used = nvec;
        desc->msi_attrib.multiple = order_base_2(nvec);

        msg.address_lo = rcar_pci_read_reg(pcie, PCIEMSIALR) & ~MSIFE;
        msg.address_hi = rcar_pci_read_reg(pcie, PCIEMSIAUR);
        msg.data = hwirq;

        pci_write_msi_msg(irq, &msg);

        return 0;
}

static void rcar_msi_teardown_irq(struct msi_controller *chip, unsigned int irq)
{
        struct rcar_msi *msi = to_rcar_msi(chip);
        struct irq_data *d = irq_get_irq_data(irq);

        rcar_msi_free(msi, d->hwirq);
}

static struct irq_chip rcar_msi_irq_chip = {
        .name = "R-Car 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 rcar_msi_map(struct irq_domain *domain, unsigned int irq,
                        irq_hw_number_t hwirq)
{
        irq_set_chip_and_handler(irq, &rcar_msi_irq_chip, handle_simple_irq);
        irq_set_chip_data(irq, domain->host_data);

        return 0;
}

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

static int rcar_pcie_enable_msi(struct rcar_pcie *pcie)
{
        struct device *dev = pcie->dev;
        struct rcar_msi *msi = &pcie->msi;
        unsigned long base;
        int err, i;

        mutex_init(&msi->lock);

        msi->chip.dev = dev;
        msi->chip.setup_irq = rcar_msi_setup_irq;
        msi->chip.setup_irqs = rcar_msi_setup_irqs;
        msi->chip.teardown_irq = rcar_msi_teardown_irq;

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

        for (i = 0; i < INT_PCI_MSI_NR; i++)
                irq_create_mapping(msi->domain, i);

        /* Two irqs are for MSI, but they are also used for non-MSI irqs */
        err = devm_request_irq(dev, msi->irq1, rcar_pcie_msi_irq,
                               IRQF_SHARED | IRQF_NO_THREAD,
                               rcar_msi_irq_chip.name, pcie);
        if (err < 0) {
                dev_err(dev, "failed to request IRQ: %d\n", err);
                goto err;
        }

        err = devm_request_irq(dev, msi->irq2, rcar_pcie_msi_irq,
                               IRQF_SHARED | IRQF_NO_THREAD,
                               rcar_msi_irq_chip.name, pcie);
        if (err < 0) {
                dev_err(dev, "failed to request IRQ: %d\n", err);
                goto err;
        }

        /* setup MSI data target */
        msi->pages = __get_free_pages(GFP_KERNEL, 0);
        base = virt_to_phys((void *)msi->pages);

        rcar_pci_write_reg(pcie, base | MSIFE, PCIEMSIALR);
        rcar_pci_write_reg(pcie, 0, PCIEMSIAUR);

        /* enable all MSI interrupts */
        rcar_pci_write_reg(pcie, 0xffffffff, PCIEMSIIER);

        return 0;

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

static int rcar_pcie_get_resources(struct rcar_pcie *pcie)
{
        struct device *dev = pcie->dev;
        struct resource res;
        int err, i;

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

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

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

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

        i = irq_of_parse_and_map(dev->of_node, 0);
        if (!i) {
                dev_err(dev, "cannot get platform resources for msi interrupt\n");
                err = -ENOENT;
                goto err_map_reg;
        }
        pcie->msi.irq1 = i;

        i = irq_of_parse_and_map(dev->of_node, 1);
        if (!i) {
                dev_err(dev, "cannot get platform resources for msi interrupt\n");
                err = -ENOENT;
                goto err_map_reg;
        }
        pcie->msi.irq2 = i;

        return 0;

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

        return err;
}

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

        if (restype & IORESOURCE_PREFETCH)
                flags |= LAM_PREFETCH;

        /*
         * If the size of the range is larger than the alignment of the start
         * address, we have to use multiple entries to perform the mapping.
         */
        if (cpu_addr > 0) {
                unsigned long nr_zeros = __ffs64(cpu_addr);
                u64 alignment = 1ULL << nr_zeros;

                size = min(range->size, alignment);
        } else {
                size = range->size;
        }
        /* Hardware supports max 4GiB inbound region */
        size = min(size, 1ULL << 32);

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

        while (cpu_addr < cpu_end) {
                /*
                 * Set up 64-bit inbound regions as the range parser doesn't
                 * distinguish between 32 and 64-bit types.
                 */

                rcar_pci_write_reg(pcie, lower_32_bits(pci_addr),
                                   PCIEPRAR(idx));
                rcar_pci_write_reg(pcie, lower_32_bits(cpu_addr), PCIELAR(idx));
                rcar_pci_write_reg(pcie, lower_32_bits(mask) | flags,
                                   PCIELAMR(idx));

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

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

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

        return 0;
}

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

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

        /* Get the dma-ranges from DT */
        for_each_of_pci_range(&parser, &range) {
                u64 end = range.cpu_addr + range.size - 1;

                dev_dbg(pcie->dev, "0x%08x 0x%016llx..0x%016llx -> 0x%016llx\n",
                        range.flags, range.cpu_addr, end, range.pci_addr);

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

        return 0;
}

static const struct of_device_id rcar_pcie_of_match[] = {
        { .compatible = "renesas,pcie-r8a7779", .data = rcar_pcie_hw_init_h1 },
        { .compatible = "renesas,pcie-r8a7790",
          .data = rcar_pcie_hw_init_gen2 },
        { .compatible = "renesas,pcie-r8a7791",
          .data = rcar_pcie_hw_init_gen2 },
        { .compatible = "renesas,pcie-rcar-gen2",
          .data = rcar_pcie_hw_init_gen2 },
        { .compatible = "renesas,pcie-r8a7795", .data = rcar_pcie_hw_init },
        { .compatible = "renesas,pcie-rcar-gen3", .data = rcar_pcie_hw_init },
        {},
};

static int rcar_pcie_parse_request_of_pci_ranges(struct rcar_pcie *pci)
{
        int err;
        struct device *dev = pci->dev;
        struct device_node *np = dev->of_node;
        resource_size_t iobase;
        struct resource_entry *win, *tmp;

        err = of_pci_get_host_bridge_resources(np, 0, 0xff, &pci->resources,
                                               &iobase);
        if (err)
                return err;

        err = devm_request_pci_bus_resources(dev, &pci->resources);
        if (err)
                goto out_release_res;

        resource_list_for_each_entry_safe(win, tmp, &pci->resources) {
                struct resource *res = win->res;

                if (resource_type(res) == IORESOURCE_IO) {
                        err = pci_remap_iospace(res, iobase);
                        if (err) {
                                dev_warn(dev, "error %d: failed to map resource %pR\n",
                                         err, res);

                                resource_list_destroy_entry(win);
                        }
                }
        }

        return 0;

out_release_res:
        pci_free_resource_list(&pci->resources);
        return err;
}

static int rcar_pcie_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct rcar_pcie *pcie;
        unsigned int data;
        int err;
        int (*hw_init_fn)(struct rcar_pcie *);
        struct pci_host_bridge *bridge;

        bridge = pci_alloc_host_bridge(sizeof(*pcie));
        if (!bridge)
                return -ENOMEM;

        pcie = pci_host_bridge_priv(bridge);

        pcie->dev = dev;

        INIT_LIST_HEAD(&pcie->resources);

        err = rcar_pcie_parse_request_of_pci_ranges(pcie);
        if (err)
                goto err_free_bridge;

        err = rcar_pcie_get_resources(pcie);
        if (err < 0) {
                dev_err(dev, "failed to request resources: %d\n", err);
                goto err_free_resource_list;
        }

        err = rcar_pcie_parse_map_dma_ranges(pcie, dev->of_node);
        if (err)
                goto err_free_resource_list;

        pm_runtime_enable(dev);
        err = pm_runtime_get_sync(dev);
        if (err < 0) {
                dev_err(dev, "pm_runtime_get_sync failed\n");
                goto err_pm_disable;
        }

        /* Failure to get a link might just be that no cards are inserted */
        hw_init_fn = of_device_get_match_data(dev);
        err = hw_init_fn(pcie);
        if (err) {
                dev_info(dev, "PCIe link down\n");
                err = -ENODEV;
                goto err_pm_put;
        }

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

        if (IS_ENABLED(CONFIG_PCI_MSI)) {
                err = rcar_pcie_enable_msi(pcie);
                if (err < 0) {
                        dev_err(dev,
                                "failed to enable MSI support: %d\n",
                                err);
                        goto err_pm_put;
                }
        }

        err = rcar_pcie_enable(pcie);
        if (err)
                goto err_pm_put;

        return 0;

err_pm_put:
        pm_runtime_put(dev);

err_pm_disable:
        pm_runtime_disable(dev);

err_free_resource_list:
        pci_free_resource_list(&pcie->resources);
err_free_bridge:
        pci_free_host_bridge(bridge);

        return err;
}

static struct platform_driver rcar_pcie_driver = {
        .driver = {
                .name = "rcar-pcie",
                .of_match_table = rcar_pcie_of_match,
                .suppress_bind_attrs = true,
        },
        .probe = rcar_pcie_probe,
};
builtin_platform_driver(rcar_pcie_driver);