// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright Altera Corporation (C) 2013-2015. All rights reserved
 *
 * Author: Ley Foon Tan <lftan@altera.com>
 * Description: Altera PCIe host controller driver
 */

#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/of_pci.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include "../pci.h"

#define RP_TX_REG0                      0x2000
#define RP_TX_REG1                      0x2004
#define RP_TX_CNTRL                     0x2008
#define RP_TX_EOP                       0x2
#define RP_TX_SOP                       0x1
#define RP_RXCPL_STATUS                 0x2010
#define RP_RXCPL_EOP                    0x2
#define RP_RXCPL_SOP                    0x1
#define RP_RXCPL_REG0                   0x2014
#define RP_RXCPL_REG1                   0x2018
#define P2A_INT_STATUS                  0x3060
#define P2A_INT_STS_ALL                 0xf
#define P2A_INT_ENABLE                  0x3070
#define P2A_INT_ENA_ALL                 0xf
#define RP_LTSSM                        0x3c64
#define RP_LTSSM_MASK                   0x1f
#define LTSSM_L0                        0xf

#define S10_RP_TX_CNTRL                 0x2004
#define S10_RP_RXCPL_REG                0x2008
#define S10_RP_RXCPL_STATUS             0x200C
#define S10_RP_CFG_ADDR(pcie, reg)      \
        (((pcie)->hip_base) + (reg) + (1 << 20))
#define S10_RP_SECONDARY(pcie)          \
        readb(S10_RP_CFG_ADDR(pcie, PCI_SECONDARY_BUS))

/* TLP configuration type 0 and 1 */
#define TLP_FMTTYPE_CFGRD0              0x04    /* Configuration Read Type 0 */
#define TLP_FMTTYPE_CFGWR0              0x44    /* Configuration Write Type 0 */
#define TLP_FMTTYPE_CFGRD1              0x05    /* Configuration Read Type 1 */
#define TLP_FMTTYPE_CFGWR1              0x45    /* Configuration Write Type 1 */
#define TLP_PAYLOAD_SIZE                0x01
#define TLP_READ_TAG                    0x1d
#define TLP_WRITE_TAG                   0x10
#define RP_DEVFN                        0
#define TLP_REQ_ID(bus, devfn)          (((bus) << 8) | (devfn))
#define TLP_CFG_DW0(pcie, cfg)          \
                (((cfg) << 24) |        \
                  TLP_PAYLOAD_SIZE)
#define TLP_CFG_DW1(pcie, tag, be)      \
        (((TLP_REQ_ID(pcie->root_bus_nr,  RP_DEVFN)) << 16) | (tag << 8) | (be))
#define TLP_CFG_DW2(bus, devfn, offset) \
                                (((bus) << 24) | ((devfn) << 16) | (offset))
#define TLP_COMP_STATUS(s)              (((s) >> 13) & 7)
#define TLP_BYTE_COUNT(s)               (((s) >> 0) & 0xfff)
#define TLP_HDR_SIZE                    3
#define TLP_LOOP                        500

#define LINK_UP_TIMEOUT                 HZ
#define LINK_RETRAIN_TIMEOUT            HZ

#define DWORD_MASK                      3

#define S10_TLP_FMTTYPE_CFGRD0          0x05
#define S10_TLP_FMTTYPE_CFGRD1          0x04
#define S10_TLP_FMTTYPE_CFGWR0          0x45
#define S10_TLP_FMTTYPE_CFGWR1          0x44

enum altera_pcie_version {
        ALTERA_PCIE_V1 = 0,
        ALTERA_PCIE_V2,
};

struct altera_pcie {
        struct platform_device  *pdev;
        void __iomem            *cra_base;
        void __iomem            *hip_base;
        int                     irq;
        u8                      root_bus_nr;
        struct irq_domain       *irq_domain;
        struct resource         bus_range;
        struct list_head        resources;
        const struct altera_pcie_data   *pcie_data;
};

struct altera_pcie_ops {
        int (*tlp_read_pkt)(struct altera_pcie *pcie, u32 *value);
        void (*tlp_write_pkt)(struct altera_pcie *pcie, u32 *headers,
                              u32 data, bool align);
        bool (*get_link_status)(struct altera_pcie *pcie);
        int (*rp_read_cfg)(struct altera_pcie *pcie, int where,
                           int size, u32 *value);
        int (*rp_write_cfg)(struct altera_pcie *pcie, u8 busno,
                            int where, int size, u32 value);
};

struct altera_pcie_data {
        const struct altera_pcie_ops *ops;
        enum altera_pcie_version version;
        u32 cap_offset;         /* PCIe capability structure register offset */
        u32 cfgrd0;
        u32 cfgrd1;
        u32 cfgwr0;
        u32 cfgwr1;
};

struct tlp_rp_regpair_t {
        u32 ctrl;
        u32 reg0;
        u32 reg1;
};

static inline void cra_writel(struct altera_pcie *pcie, const u32 value,
                              const u32 reg)
{
        writel_relaxed(value, pcie->cra_base + reg);
}

static inline u32 cra_readl(struct altera_pcie *pcie, const u32 reg)
{
        return readl_relaxed(pcie->cra_base + reg);
}

static bool altera_pcie_link_up(struct altera_pcie *pcie)
{
        return !!((cra_readl(pcie, RP_LTSSM) & RP_LTSSM_MASK) == LTSSM_L0);
}

static bool s10_altera_pcie_link_up(struct altera_pcie *pcie)
{
        void __iomem *addr = S10_RP_CFG_ADDR(pcie,
                                   pcie->pcie_data->cap_offset +
                                   PCI_EXP_LNKSTA);

        return !!(readw(addr) & PCI_EXP_LNKSTA_DLLLA);
}

/*
 * Altera PCIe port uses BAR0 of RC's configuration space as the translation
 * from PCI bus to native BUS.  Entire DDR region is mapped into PCIe space
 * using these registers, so it can be reached by DMA from EP devices.
 * This BAR0 will also access to MSI vector when receiving MSI/MSIX interrupt
 * from EP devices, eventually trigger interrupt to GIC.  The BAR0 of bridge
 * should be hidden during enumeration to avoid the sizing and resource
 * allocation by PCIe core.
 */
static bool altera_pcie_hide_rc_bar(struct pci_bus *bus, unsigned int  devfn,
                                    int offset)
{
        if (pci_is_root_bus(bus) && (devfn == 0) &&
            (offset == PCI_BASE_ADDRESS_0))
                return true;

        return false;
}

static void tlp_write_tx(struct altera_pcie *pcie,
                         struct tlp_rp_regpair_t *tlp_rp_regdata)
{
        cra_writel(pcie, tlp_rp_regdata->reg0, RP_TX_REG0);
        cra_writel(pcie, tlp_rp_regdata->reg1, RP_TX_REG1);
        cra_writel(pcie, tlp_rp_regdata->ctrl, RP_TX_CNTRL);
}

static void s10_tlp_write_tx(struct altera_pcie *pcie, u32 reg0, u32 ctrl)
{
        cra_writel(pcie, reg0, RP_TX_REG0);
        cra_writel(pcie, ctrl, S10_RP_TX_CNTRL);
}

static bool altera_pcie_valid_device(struct altera_pcie *pcie,
                                     struct pci_bus *bus, int dev)
{
        /* If there is no link, then there is no device */
        if (bus->number != pcie->root_bus_nr) {
                if (!pcie->pcie_data->ops->get_link_status(pcie))
                        return false;
        }

        /* access only one slot on each root port */
        if (bus->number == pcie->root_bus_nr && dev > 0)
                return false;

         return true;
}

static int tlp_read_packet(struct altera_pcie *pcie, u32 *value)
{
        int i;
        bool sop = false;
        u32 ctrl;
        u32 reg0, reg1;
        u32 comp_status = 1;

        /*
         * Minimum 2 loops to read TLP headers and 1 loop to read data
         * payload.
         */
        for (i = 0; i < TLP_LOOP; i++) {
                ctrl = cra_readl(pcie, RP_RXCPL_STATUS);
                if ((ctrl & RP_RXCPL_SOP) || (ctrl & RP_RXCPL_EOP) || sop) {
                        reg0 = cra_readl(pcie, RP_RXCPL_REG0);
                        reg1 = cra_readl(pcie, RP_RXCPL_REG1);

                        if (ctrl & RP_RXCPL_SOP) {
                                sop = true;
                                comp_status = TLP_COMP_STATUS(reg1);
                        }

                        if (ctrl & RP_RXCPL_EOP) {
                                if (comp_status)
                                        return PCIBIOS_DEVICE_NOT_FOUND;

                                if (value)
                                        *value = reg0;

                                return PCIBIOS_SUCCESSFUL;
                        }
                }
                udelay(5);
        }

        return PCIBIOS_DEVICE_NOT_FOUND;
}

static int s10_tlp_read_packet(struct altera_pcie *pcie, u32 *value)
{
        u32 ctrl;
        u32 comp_status;
        u32 dw[4];
        u32 count;
        struct device *dev = &pcie->pdev->dev;

        for (count = 0; count < TLP_LOOP; count++) {
                ctrl = cra_readl(pcie, S10_RP_RXCPL_STATUS);
                if (ctrl & RP_RXCPL_SOP) {
                        /* Read first DW */
                        dw[0] = cra_readl(pcie, S10_RP_RXCPL_REG);
                        break;
                }

                udelay(5);
        }

        /* SOP detection failed, return error */
        if (count == TLP_LOOP)
                return PCIBIOS_DEVICE_NOT_FOUND;

        count = 1;

        /* Poll for EOP */
        while (count < ARRAY_SIZE(dw)) {
                ctrl = cra_readl(pcie, S10_RP_RXCPL_STATUS);
                dw[count++] = cra_readl(pcie, S10_RP_RXCPL_REG);
                if (ctrl & RP_RXCPL_EOP) {
                        comp_status = TLP_COMP_STATUS(dw[1]);
                        if (comp_status)
                                return PCIBIOS_DEVICE_NOT_FOUND;

                        if (value && TLP_BYTE_COUNT(dw[1]) == sizeof(u32) &&
                            count == 4)
                                *value = dw[3];

                        return PCIBIOS_SUCCESSFUL;
                }
        }

        dev_warn(dev, "Malformed TLP packet\n");

        return PCIBIOS_DEVICE_NOT_FOUND;
}

static void tlp_write_packet(struct altera_pcie *pcie, u32 *headers,
                             u32 data, bool align)
{
        struct tlp_rp_regpair_t tlp_rp_regdata;

        tlp_rp_regdata.reg0 = headers[0];
        tlp_rp_regdata.reg1 = headers[1];
        tlp_rp_regdata.ctrl = RP_TX_SOP;
        tlp_write_tx(pcie, &tlp_rp_regdata);

        if (align) {
                tlp_rp_regdata.reg0 = headers[2];
                tlp_rp_regdata.reg1 = 0;
                tlp_rp_regdata.ctrl = 0;
                tlp_write_tx(pcie, &tlp_rp_regdata);

                tlp_rp_regdata.reg0 = data;
                tlp_rp_regdata.reg1 = 0;
        } else {
                tlp_rp_regdata.reg0 = headers[2];
                tlp_rp_regdata.reg1 = data;
        }

        tlp_rp_regdata.ctrl = RP_TX_EOP;
        tlp_write_tx(pcie, &tlp_rp_regdata);
}

static void s10_tlp_write_packet(struct altera_pcie *pcie, u32 *headers,
                                 u32 data, bool dummy)
{
        s10_tlp_write_tx(pcie, headers[0], RP_TX_SOP);
        s10_tlp_write_tx(pcie, headers[1], 0);
        s10_tlp_write_tx(pcie, headers[2], 0);
        s10_tlp_write_tx(pcie, data, RP_TX_EOP);
}

static void get_tlp_header(struct altera_pcie *pcie, u8 bus, u32 devfn,
                           int where, u8 byte_en, bool read, u32 *headers)
{
        u8 cfg;
        u8 cfg0 = read ? pcie->pcie_data->cfgrd0 : pcie->pcie_data->cfgwr0;
        u8 cfg1 = read ? pcie->pcie_data->cfgrd1 : pcie->pcie_data->cfgwr1;
        u8 tag = read ? TLP_READ_TAG : TLP_WRITE_TAG;

        if (pcie->pcie_data->version == ALTERA_PCIE_V1)
                cfg = (bus == pcie->root_bus_nr) ? cfg0 : cfg1;
        else
                cfg = (bus > S10_RP_SECONDARY(pcie)) ? cfg0 : cfg1;

        headers[0] = TLP_CFG_DW0(pcie, cfg);
        headers[1] = TLP_CFG_DW1(pcie, tag, byte_en);
        headers[2] = TLP_CFG_DW2(bus, devfn, where);
}

static int tlp_cfg_dword_read(struct altera_pcie *pcie, u8 bus, u32 devfn,
                              int where, u8 byte_en, u32 *value)
{
        u32 headers[TLP_HDR_SIZE];

        get_tlp_header(pcie, bus, devfn, where, byte_en, true,
                       headers);

        pcie->pcie_data->ops->tlp_write_pkt(pcie, headers, 0, false);

        return pcie->pcie_data->ops->tlp_read_pkt(pcie, value);
}

static int tlp_cfg_dword_write(struct altera_pcie *pcie, u8 bus, u32 devfn,
                               int where, u8 byte_en, u32 value)
{
        u32 headers[TLP_HDR_SIZE];
        int ret;

        get_tlp_header(pcie, bus, devfn, where, byte_en, false,
                       headers);

        /* check alignment to Qword */
        if ((where & 0x7) == 0)
                pcie->pcie_data->ops->tlp_write_pkt(pcie, headers,
                                                    value, true);
        else
                pcie->pcie_data->ops->tlp_write_pkt(pcie, headers,
                                                    value, false);

        ret = pcie->pcie_data->ops->tlp_read_pkt(pcie, NULL);
        if (ret != PCIBIOS_SUCCESSFUL)
                return ret;

        /*
         * Monitor changes to PCI_PRIMARY_BUS register on root port
         * and update local copy of root bus number accordingly.
         */
        if ((bus == pcie->root_bus_nr) && (where == PCI_PRIMARY_BUS))
                pcie->root_bus_nr = (u8)(value);

        return PCIBIOS_SUCCESSFUL;
}

static int s10_rp_read_cfg(struct altera_pcie *pcie, int where,
                           int size, u32 *value)
{
        void __iomem *addr = S10_RP_CFG_ADDR(pcie, where);

        switch (size) {
        case 1:
                *value = readb(addr);
                break;
        case 2:
                *value = readw(addr);
                break;
        default:
                *value = readl(addr);
                break;
        }

        return PCIBIOS_SUCCESSFUL;
}

static int s10_rp_write_cfg(struct altera_pcie *pcie, u8 busno,
                            int where, int size, u32 value)
{
        void __iomem *addr = S10_RP_CFG_ADDR(pcie, where);

        switch (size) {
        case 1:
                writeb(value, addr);
                break;
        case 2:
                writew(value, addr);
                break;
        default:
                writel(value, addr);
                break;
        }

        /*
         * Monitor changes to PCI_PRIMARY_BUS register on root port
         * and update local copy of root bus number accordingly.
         */
        if (busno == pcie->root_bus_nr && where == PCI_PRIMARY_BUS)
                pcie->root_bus_nr = value & 0xff;

        return PCIBIOS_SUCCESSFUL;
}

static int _altera_pcie_cfg_read(struct altera_pcie *pcie, u8 busno,
                                 unsigned int devfn, int where, int size,
                                 u32 *value)
{
        int ret;
        u32 data;
        u8 byte_en;

        if (busno == pcie->root_bus_nr && pcie->pcie_data->ops->rp_read_cfg)
                return pcie->pcie_data->ops->rp_read_cfg(pcie, where,
                                                         size, value);

        switch (size) {
        case 1:
                byte_en = 1 << (where & 3);
                break;
        case 2:
                byte_en = 3 << (where & 3);
                break;
        default:
                byte_en = 0xf;
                break;
        }

        ret = tlp_cfg_dword_read(pcie, busno, devfn,
                                 (where & ~DWORD_MASK), byte_en, &data);
        if (ret != PCIBIOS_SUCCESSFUL)
                return ret;

        switch (size) {
        case 1:
                *value = (data >> (8 * (where & 0x3))) & 0xff;
                break;
        case 2:
                *value = (data >> (8 * (where & 0x2))) & 0xffff;
                break;
        default:
                *value = data;
                break;
        }

        return PCIBIOS_SUCCESSFUL;
}

static int _altera_pcie_cfg_write(struct altera_pcie *pcie, u8 busno,
                                  unsigned int devfn, int where, int size,
                                  u32 value)
{
        u32 data32;
        u32 shift = 8 * (where & 3);
        u8 byte_en;

        if (busno == pcie->root_bus_nr && pcie->pcie_data->ops->rp_write_cfg)
                return pcie->pcie_data->ops->rp_write_cfg(pcie, busno,
                                                     where, size, value);

        switch (size) {
        case 1:
                data32 = (value & 0xff) << shift;
                byte_en = 1 << (where & 3);
                break;
        case 2:
                data32 = (value & 0xffff) << shift;
                byte_en = 3 << (where & 3);
                break;
        default:
                data32 = value;
                byte_en = 0xf;
                break;
        }

        return tlp_cfg_dword_write(pcie, busno, devfn, (where & ~DWORD_MASK),
                                   byte_en, data32);
}

static int altera_pcie_cfg_read(struct pci_bus *bus, unsigned int devfn,
                                int where, int size, u32 *value)
{
        struct altera_pcie *pcie = bus->sysdata;

        if (altera_pcie_hide_rc_bar(bus, devfn, where))
                return PCIBIOS_BAD_REGISTER_NUMBER;

        if (!altera_pcie_valid_device(pcie, bus, PCI_SLOT(devfn))) {
                *value = 0xffffffff;
                return PCIBIOS_DEVICE_NOT_FOUND;
        }

        return _altera_pcie_cfg_read(pcie, bus->number, devfn, where, size,
                                     value);
}

static int altera_pcie_cfg_write(struct pci_bus *bus, unsigned int devfn,
                                 int where, int size, u32 value)
{
        struct altera_pcie *pcie = bus->sysdata;

        if (altera_pcie_hide_rc_bar(bus, devfn, where))
                return PCIBIOS_BAD_REGISTER_NUMBER;

        if (!altera_pcie_valid_device(pcie, bus, PCI_SLOT(devfn)))
                return PCIBIOS_DEVICE_NOT_FOUND;

        return _altera_pcie_cfg_write(pcie, bus->number, devfn, where, size,
                                     value);
}

static struct pci_ops altera_pcie_ops = {
        .read = altera_pcie_cfg_read,
        .write = altera_pcie_cfg_write,
};

static int altera_read_cap_word(struct altera_pcie *pcie, u8 busno,
                                unsigned int devfn, int offset, u16 *value)
{
        u32 data;
        int ret;

        ret = _altera_pcie_cfg_read(pcie, busno, devfn,
                                    pcie->pcie_data->cap_offset + offset,
                                    sizeof(*value),
                                    &data);
        *value = data;
        return ret;
}

static int altera_write_cap_word(struct altera_pcie *pcie, u8 busno,
                                 unsigned int devfn, int offset, u16 value)
{
        return _altera_pcie_cfg_write(pcie, busno, devfn,
                                      pcie->pcie_data->cap_offset + offset,
                                      sizeof(value),
                                      value);
}

static void altera_wait_link_retrain(struct altera_pcie *pcie)
{
        struct device *dev = &pcie->pdev->dev;
        u16 reg16;
        unsigned long start_jiffies;

        /* Wait for link training end. */
        start_jiffies = jiffies;
        for (;;) {
                altera_read_cap_word(pcie, pcie->root_bus_nr, RP_DEVFN,
                                     PCI_EXP_LNKSTA, &reg16);
                if (!(reg16 & PCI_EXP_LNKSTA_LT))
                        break;

                if (time_after(jiffies, start_jiffies + LINK_RETRAIN_TIMEOUT)) {
                        dev_err(dev, "link retrain timeout\n");
                        break;
                }
                udelay(100);
        }

        /* Wait for link is up */
        start_jiffies = jiffies;
        for (;;) {
                if (pcie->pcie_data->ops->get_link_status(pcie))
                        break;

                if (time_after(jiffies, start_jiffies + LINK_UP_TIMEOUT)) {
                        dev_err(dev, "link up timeout\n");
                        break;
                }
                udelay(100);
        }
}

static void altera_pcie_retrain(struct altera_pcie *pcie)
{
        u16 linkcap, linkstat, linkctl;

        if (!pcie->pcie_data->ops->get_link_status(pcie))
                return;

        /*
         * Set the retrain bit if the PCIe rootport support > 2.5GB/s, but
         * current speed is 2.5 GB/s.
         */
        altera_read_cap_word(pcie, pcie->root_bus_nr, RP_DEVFN, PCI_EXP_LNKCAP,
                             &linkcap);
        if ((linkcap & PCI_EXP_LNKCAP_SLS) <= PCI_EXP_LNKCAP_SLS_2_5GB)
                return;

        altera_read_cap_word(pcie, pcie->root_bus_nr, RP_DEVFN, PCI_EXP_LNKSTA,
                             &linkstat);
        if ((linkstat & PCI_EXP_LNKSTA_CLS) == PCI_EXP_LNKSTA_CLS_2_5GB) {
                altera_read_cap_word(pcie, pcie->root_bus_nr, RP_DEVFN,
                                     PCI_EXP_LNKCTL, &linkctl);
                linkctl |= PCI_EXP_LNKCTL_RL;
                altera_write_cap_word(pcie, pcie->root_bus_nr, RP_DEVFN,
                                      PCI_EXP_LNKCTL, linkctl);

                altera_wait_link_retrain(pcie);
        }
}

static int altera_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
                                irq_hw_number_t hwirq)
{
        irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
        irq_set_chip_data(irq, domain->host_data);
        return 0;
}

static const struct irq_domain_ops intx_domain_ops = {
        .map = altera_pcie_intx_map,
        .xlate = pci_irqd_intx_xlate,
};

static void altera_pcie_isr(struct irq_desc *desc)
{
        struct irq_chip *chip = irq_desc_get_chip(desc);
        struct altera_pcie *pcie;
        struct device *dev;
        unsigned long status;
        u32 bit;
        u32 virq;

        chained_irq_enter(chip, desc);
        pcie = irq_desc_get_handler_data(desc);
        dev = &pcie->pdev->dev;

        while ((status = cra_readl(pcie, P2A_INT_STATUS)
                & P2A_INT_STS_ALL) != 0) {
                for_each_set_bit(bit, &status, PCI_NUM_INTX) {
                        /* clear interrupts */
                        cra_writel(pcie, 1 << bit, P2A_INT_STATUS);

                        virq = irq_find_mapping(pcie->irq_domain, bit);
                        if (virq)
                                generic_handle_irq(virq);
                        else
                                dev_err(dev, "unexpected IRQ, INT%d\n", bit);
                }
        }

        chained_irq_exit(chip, desc);
}

static int altera_pcie_parse_request_of_pci_ranges(struct altera_pcie *pcie)
{
        int err, res_valid = 0;
        struct device *dev = &pcie->pdev->dev;
        struct resource_entry *win;

        err = devm_of_pci_get_host_bridge_resources(dev, 0, 0xff,
                                                    &pcie->resources, NULL);
        if (err)
                return err;

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

        resource_list_for_each_entry(win, &pcie->resources) {
                struct resource *res = win->res;

                if (resource_type(res) == IORESOURCE_MEM)
                        res_valid |= !(res->flags & IORESOURCE_PREFETCH);
        }

        if (res_valid)
                return 0;

        dev_err(dev, "non-prefetchable memory resource required\n");
        err = -EINVAL;

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

static int altera_pcie_init_irq_domain(struct altera_pcie *pcie)
{
        struct device *dev = &pcie->pdev->dev;
        struct device_node *node = dev->of_node;

        /* Setup INTx */
        pcie->irq_domain = irq_domain_add_linear(node, PCI_NUM_INTX,
                                        &intx_domain_ops, pcie);
        if (!pcie->irq_domain) {
                dev_err(dev, "Failed to get a INTx IRQ domain\n");
                return -ENOMEM;
        }

        return 0;
}

static void altera_pcie_irq_teardown(struct altera_pcie *pcie)
{
        irq_set_chained_handler_and_data(pcie->irq, NULL, NULL);
        irq_domain_remove(pcie->irq_domain);
        irq_dispose_mapping(pcie->irq);
}

static int altera_pcie_parse_dt(struct altera_pcie *pcie)
{
        struct device *dev = &pcie->pdev->dev;
        struct platform_device *pdev = pcie->pdev;
        struct resource *cra;
        struct resource *hip;

        cra = platform_get_resource_byname(pdev, IORESOURCE_MEM, "Cra");
        pcie->cra_base = devm_ioremap_resource(dev, cra);
        if (IS_ERR(pcie->cra_base))
                return PTR_ERR(pcie->cra_base);

        if (pcie->pcie_data->version == ALTERA_PCIE_V2) {
                hip = platform_get_resource_byname(pdev, IORESOURCE_MEM, "Hip");
                pcie->hip_base = devm_ioremap_resource(&pdev->dev, hip);
                if (IS_ERR(pcie->hip_base))
                        return PTR_ERR(pcie->hip_base);
        }

        /* setup IRQ */
        pcie->irq = platform_get_irq(pdev, 0);
        if (pcie->irq < 0) {
                dev_err(dev, "failed to get IRQ: %d\n", pcie->irq);
                return pcie->irq;
        }

        irq_set_chained_handler_and_data(pcie->irq, altera_pcie_isr, pcie);
        return 0;
}

static void altera_pcie_host_init(struct altera_pcie *pcie)
{
        altera_pcie_retrain(pcie);
}

static const struct altera_pcie_ops altera_pcie_ops_1_0 = {
        .tlp_read_pkt = tlp_read_packet,
        .tlp_write_pkt = tlp_write_packet,
        .get_link_status = altera_pcie_link_up,
};

static const struct altera_pcie_ops altera_pcie_ops_2_0 = {
        .tlp_read_pkt = s10_tlp_read_packet,
        .tlp_write_pkt = s10_tlp_write_packet,
        .get_link_status = s10_altera_pcie_link_up,
        .rp_read_cfg = s10_rp_read_cfg,
        .rp_write_cfg = s10_rp_write_cfg,
};

static const struct altera_pcie_data altera_pcie_1_0_data = {
        .ops = &altera_pcie_ops_1_0,
        .cap_offset = 0x80,
        .version = ALTERA_PCIE_V1,
        .cfgrd0 = TLP_FMTTYPE_CFGRD0,
        .cfgrd1 = TLP_FMTTYPE_CFGRD1,
        .cfgwr0 = TLP_FMTTYPE_CFGWR0,
        .cfgwr1 = TLP_FMTTYPE_CFGWR1,
};

static const struct altera_pcie_data altera_pcie_2_0_data = {
        .ops = &altera_pcie_ops_2_0,
        .version = ALTERA_PCIE_V2,
        .cap_offset = 0x70,
        .cfgrd0 = S10_TLP_FMTTYPE_CFGRD0,
        .cfgrd1 = S10_TLP_FMTTYPE_CFGRD1,
        .cfgwr0 = S10_TLP_FMTTYPE_CFGWR0,
        .cfgwr1 = S10_TLP_FMTTYPE_CFGWR1,
};

static const struct of_device_id altera_pcie_of_match[] = {
        {.compatible = "altr,pcie-root-port-1.0",
         .data = &altera_pcie_1_0_data },
        {.compatible = "altr,pcie-root-port-2.0",
         .data = &altera_pcie_2_0_data },
        {},
};

static int altera_pcie_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct altera_pcie *pcie;
        struct pci_bus *bus;
        struct pci_bus *child;
        struct pci_host_bridge *bridge;
        int ret;
        const struct of_device_id *match;

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

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

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

        pcie->pcie_data = match->data;

        ret = altera_pcie_parse_dt(pcie);
        if (ret) {
                dev_err(dev, "Parsing DT failed\n");
                return ret;
        }

        INIT_LIST_HEAD(&pcie->resources);

        ret = altera_pcie_parse_request_of_pci_ranges(pcie);
        if (ret) {
                dev_err(dev, "Failed add resources\n");
                return ret;
        }

        ret = altera_pcie_init_irq_domain(pcie);
        if (ret) {
                dev_err(dev, "Failed creating IRQ Domain\n");
                return ret;
        }

        /* clear all interrupts */
        cra_writel(pcie, P2A_INT_STS_ALL, P2A_INT_STATUS);
        /* enable all interrupts */
        cra_writel(pcie, P2A_INT_ENA_ALL, P2A_INT_ENABLE);
        altera_pcie_host_init(pcie);

        list_splice_init(&pcie->resources, &bridge->windows);
        bridge->dev.parent = dev;
        bridge->sysdata = pcie;
        bridge->busnr = pcie->root_bus_nr;
        bridge->ops = &altera_pcie_ops;
        bridge->map_irq = of_irq_parse_and_map_pci;
        bridge->swizzle_irq = pci_common_swizzle;

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

        bus = bridge->bus;

        pci_assign_unassigned_bus_resources(bus);

        /* Configure PCI Express setting. */
        list_for_each_entry(child, &bus->children, node)
                pcie_bus_configure_settings(child);

        pci_bus_add_devices(bus);
        return ret;
}

static int altera_pcie_remove(struct platform_device *pdev)
{
        struct altera_pcie *pcie = platform_get_drvdata(pdev);
        struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);

        pci_stop_root_bus(bridge->bus);
        pci_remove_root_bus(bridge->bus);
        pci_free_resource_list(&pcie->resources);
        altera_pcie_irq_teardown(pcie);

        return 0;
}

static struct platform_driver altera_pcie_driver = {
        .probe          = altera_pcie_probe,
        .remove         = altera_pcie_remove,
        .driver = {
                .name   = "altera-pcie",
                .of_match_table = altera_pcie_of_match,
        },
};

MODULE_DEVICE_TABLE(of, altera_pcie_of_match);
module_platform_driver(altera_pcie_driver);
MODULE_LICENSE("GPL v2");