// SPDX-License-Identifier: GPL-2.0
/*
 * PCIe driver for Renesas R-Car SoCs
 *  Copyright (C) 2014-2020 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/bitops.h>
#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/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>

#include "pcie-rcar.h"

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_host {
        struct rcar_pcie        pcie;
        struct phy              *phy;
        struct clk              *bus_clk;
        struct                  rcar_msi msi;
        int                     (*phy_init_fn)(struct rcar_pcie_host *host);
};

static u32 rcar_read_conf(struct rcar_pcie *pcie, int where)
{
        unsigned int shift = BITS_PER_BYTE * (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_host *host,
                unsigned char access_type, struct pci_bus *bus,
                unsigned int devfn, int where, u32 *data)
{
        struct rcar_pcie *pcie = &host->pcie;
        unsigned 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
                        rcar_pci_write_reg(pcie, *data, PCICONF(index));

                return PCIBIOS_SUCCESSFUL;
        }

        /* 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 (pci_is_root_bus(bus->parent))
                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_host *host = bus->sysdata;
        int ret;

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

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

        dev_dbg(&bus->dev, "pcie-config-read: bus=%3d devfn=0x%04x where=0x%04x size=%d val=0x%08x\n",
                bus->number, devfn, where, size, *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_host *host = bus->sysdata;
        unsigned int shift;
        u32 data;
        int ret;

        ret = rcar_pcie_config_access(host, 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%08x\n",
                bus->number, devfn, where, size, val);

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

        ret = rcar_pcie_config_access(host, 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_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 void rcar_pcie_hw_enable(struct rcar_pcie_host *host)
{
        struct rcar_pcie *pcie = &host->pcie;
        struct pci_host_bridge *bridge = pci_host_bridge_from_priv(host);
        struct resource_entry *win;
        LIST_HEAD(res);
        int i = 0;

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

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

                if (!res->flags)
                        continue;

                switch (resource_type(res)) {
                case IORESOURCE_IO:
                case IORESOURCE_MEM:
                        rcar_pcie_set_outbound(pcie, i, win);
                        i++;
                        break;
                }
        }
}

static int rcar_pcie_enable(struct rcar_pcie_host *host)
{
        struct pci_host_bridge *bridge = pci_host_bridge_from_priv(host);

        rcar_pcie_hw_enable(host);

        pci_add_flags(PCI_REASSIGN_ALL_BUS);

        bridge->sysdata = host;
        bridge->ops = &rcar_pcie_ops;
        if (IS_ENABLED(CONFIG_PCI_MSI))
                bridge->msi = &host->msi.chip;

        return pci_host_probe(bridge);
}

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, u32 addr,
                          unsigned int lane, u32 data)
{
        u32 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_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);

        err = rcar_pcie_wait_for_phyrdy(pcie);
        if (err)
                return err;

        /*
         * 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);

        rcar_pci_write_reg(pcie, MACCTLR_INIT_VAL, MACCTLR);

        /* 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_phy_init_h1(struct rcar_pcie_host *host)
{
        struct rcar_pcie *pcie = &host->pcie;

        /* 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);

        return 0;
}

static int rcar_pcie_phy_init_gen2(struct rcar_pcie_host *host)
{
        struct rcar_pcie *pcie = &host->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 0;
}

static int rcar_pcie_phy_init_gen3(struct rcar_pcie_host *host)
{
        int err;

        err = phy_init(host->phy);
        if (err)
                return err;

        err = phy_power_on(host->phy);
        if (err)
                phy_exit(host->phy);

        return err;
}

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_host *host = data;
        struct rcar_pcie *pcie = &host->pcie;
        struct rcar_msi *msi = &host->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 msi_irq;

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

                msi_irq = irq_find_mapping(msi->domain, index);
                if (msi_irq) {
                        if (test_bit(index, msi->used))
                                generic_handle_irq(msi_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_host *host = container_of(chip, struct rcar_pcie_host,
                                                   msi.chip);
        struct rcar_pcie *pcie = &host->pcie;
        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_msi *msi = to_rcar_msi(chip);
        struct rcar_pcie_host *host = container_of(chip, struct rcar_pcie_host,
                                                   msi.chip);
        struct rcar_pcie *pcie = &host->pcie;
        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 void rcar_pcie_unmap_msi(struct rcar_pcie_host *host)
{
        struct rcar_msi *msi = &host->msi;
        int i, irq;

        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);
}

static void rcar_pcie_hw_enable_msi(struct rcar_pcie_host *host)
{
        struct rcar_pcie *pcie = &host->pcie;
        struct rcar_msi *msi = &host->msi;
        unsigned long base;

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

        rcar_pci_write_reg(pcie, lower_32_bits(base) | MSIFE, PCIEMSIALR);
        rcar_pci_write_reg(pcie, upper_32_bits(base), PCIEMSIAUR);

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

static int rcar_pcie_enable_msi(struct rcar_pcie_host *host)
{
        struct rcar_pcie *pcie = &host->pcie;
        struct device *dev = pcie->dev;
        struct rcar_msi *msi = &host->msi;
        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, host);
        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, host);
        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);
        rcar_pcie_hw_enable_msi(host);

        return 0;

err:
        rcar_pcie_unmap_msi(host);
        return err;
}

static void rcar_pcie_teardown_msi(struct rcar_pcie_host *host)
{
        struct rcar_pcie *pcie = &host->pcie;
        struct rcar_msi *msi = &host->msi;

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

        /* Disable address decoding of the MSI interrupt, MSIFE */
        rcar_pci_write_reg(pcie, 0, PCIEMSIALR);

        free_pages(msi->pages, 0);

        rcar_pcie_unmap_msi(host);
}

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

        host->phy = devm_phy_optional_get(dev, "pcie");
        if (IS_ERR(host->phy))
                return PTR_ERR(host->phy);

        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);

        host->bus_clk = devm_clk_get(dev, "pcie_bus");
        if (IS_ERR(host->bus_clk)) {
                dev_err(dev, "cannot get pcie bus clock\n");
                return PTR_ERR(host->bus_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_irq1;
        }
        host->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_irq2;
        }
        host->msi.irq2 = i;

        return 0;

err_irq2:
        irq_dispose_mapping(host->msi.irq1);
err_irq1:
        return err;
}

static int rcar_pcie_inbound_ranges(struct rcar_pcie *pcie,
                                    struct resource_entry *entry,
                                    int *index)
{
        u64 restype = entry->res->flags;
        u64 cpu_addr = entry->res->start;
        u64 cpu_end = entry->res->end;
        u64 pci_addr = entry->res->start - entry->offset;
        u32 flags = LAM_64BIT | LAR_ENABLE;
        u64 mask;
        u64 size = resource_size(entry->res);
        int idx = *index;

        if (restype & IORESOURCE_PREFETCH)
                flags |= LAM_PREFETCH;

        while (cpu_addr < cpu_end) {
                if (idx >= MAX_NR_INBOUND_MAPS - 1) {
                        dev_err(pcie->dev, "Failed to map inbound regions!\n");
                        return -EINVAL;
                }
                /*
                 * 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(size, alignment);
                }
                /* Hardware supports max 4GiB inbound region */
                size = min(size, 1ULL << 32);

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

                rcar_pcie_set_inbound(pcie, cpu_addr, pci_addr,
                                      lower_32_bits(mask) | flags, idx, true);

                pci_addr += size;
                cpu_addr += size;
                idx += 2;
        }
        *index = idx;

        return 0;
}

static int rcar_pcie_parse_map_dma_ranges(struct rcar_pcie_host *host)
{
        struct pci_host_bridge *bridge = pci_host_bridge_from_priv(host);
        struct resource_entry *entry;
        int index = 0, err = 0;

        resource_list_for_each_entry(entry, &bridge->dma_ranges) {
                err = rcar_pcie_inbound_ranges(&host->pcie, entry, &index);
                if (err)
                        break;
        }

        return err;
}

static const struct of_device_id rcar_pcie_of_match[] = {
        { .compatible = "renesas,pcie-r8a7779",
          .data = rcar_pcie_phy_init_h1 },
        { .compatible = "renesas,pcie-r8a7790",
          .data = rcar_pcie_phy_init_gen2 },
        { .compatible = "renesas,pcie-r8a7791",
          .data = rcar_pcie_phy_init_gen2 },
        { .compatible = "renesas,pcie-rcar-gen2",
          .data = rcar_pcie_phy_init_gen2 },
        { .compatible = "renesas,pcie-r8a7795",
          .data = rcar_pcie_phy_init_gen3 },
        { .compatible = "renesas,pcie-rcar-gen3",
          .data = rcar_pcie_phy_init_gen3 },
        {},
};

static int rcar_pcie_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct rcar_pcie_host *host;
        struct rcar_pcie *pcie;
        u32 data;
        int err;
        struct pci_host_bridge *bridge;

        bridge = devm_pci_alloc_host_bridge(dev, sizeof(*host));
        if (!bridge)
                return -ENOMEM;

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

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

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

        err = clk_prepare_enable(host->bus_clk);
        if (err) {
                dev_err(dev, "failed to enable bus clock: %d\n", err);
                goto err_unmap_msi_irqs;
        }

        err = rcar_pcie_parse_map_dma_ranges(host);
        if (err)
                goto err_clk_disable;

        host->phy_init_fn = of_device_get_match_data(dev);
        err = host->phy_init_fn(host);
        if (err) {
                dev_err(dev, "failed to init PCIe PHY\n");
                goto err_clk_disable;
        }

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

        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(host);
                if (err < 0) {
                        dev_err(dev,
                                "failed to enable MSI support: %d\n",
                                err);
                        goto err_phy_shutdown;
                }
        }

        err = rcar_pcie_enable(host);
        if (err)
                goto err_msi_teardown;

        return 0;

err_msi_teardown:
        if (IS_ENABLED(CONFIG_PCI_MSI))
                rcar_pcie_teardown_msi(host);

err_phy_shutdown:
        if (host->phy) {
                phy_power_off(host->phy);
                phy_exit(host->phy);
        }

err_clk_disable:
        clk_disable_unprepare(host->bus_clk);

err_unmap_msi_irqs:
        irq_dispose_mapping(host->msi.irq2);
        irq_dispose_mapping(host->msi.irq1);

err_pm_put:
        pm_runtime_put(dev);
        pm_runtime_disable(dev);

        return err;
}

static int __maybe_unused rcar_pcie_resume(struct device *dev)
{
        struct rcar_pcie_host *host = dev_get_drvdata(dev);
        struct rcar_pcie *pcie = &host->pcie;
        unsigned int data;
        int err;

        err = rcar_pcie_parse_map_dma_ranges(host);
        if (err)

                return 0;

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

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

        /* Enable MSI */
        if (IS_ENABLED(CONFIG_PCI_MSI))
                rcar_pcie_hw_enable_msi(host);

        rcar_pcie_hw_enable(host);

        return 0;
}

static int rcar_pcie_resume_noirq(struct device *dev)
{
        struct rcar_pcie_host *host = dev_get_drvdata(dev);
        struct rcar_pcie *pcie = &host->pcie;

        if (rcar_pci_read_reg(pcie, PMSR) &&
            !(rcar_pci_read_reg(pcie, PCIETCTLR) & DL_DOWN))
                return 0;

        /* Re-establish the PCIe link */
        rcar_pci_write_reg(pcie, MACCTLR_INIT_VAL, MACCTLR);
        rcar_pci_write_reg(pcie, CFINIT, PCIETCTLR);
        return rcar_pcie_wait_for_dl(pcie);
}

static const struct dev_pm_ops rcar_pcie_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(NULL, rcar_pcie_resume)
        .resume_noirq = rcar_pcie_resume_noirq,
};

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