// SPDX-License-Identifier: GPL-2.0
/*
 * MediaTek PCIe host controller driver.
 *
 * Copyright (c) 2017 MediaTek Inc.
 * Author: Ryder Lee <ryder.lee@mediatek.com>
 *         Honghui Zhang <honghui.zhang@mediatek.com>
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/iopoll.h>
#include <linux/irq.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/irqchip/irq-msi-lib.h>
#include <linux/irqdomain.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/msi.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_pci.h>
#include <linux/of_platform.h>
#include <linux/pci.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <linux/reset.h>

#include "../pci.h"

/* PCIe shared registers */
#define PCIE_SYS_CFG            0x00
#define PCIE_INT_ENABLE         0x0c
#define PCIE_CFG_ADDR           0x20
#define PCIE_CFG_DATA           0x24

/* PCIe per port registers */
#define PCIE_BAR0_SETUP         0x10
#define PCIE_CLASS              0x34
#define PCIE_LINK_STATUS        0x50

#define PCIE_PORT_INT_EN(x)     BIT(20 + (x))
#define PCIE_PORT_PERST(x)      BIT(1 + (x))
#define PCIE_PORT_LINKUP        BIT(0)
#define PCIE_BAR_MAP_MAX        GENMASK(31, 16)

#define PCIE_BAR_ENABLE         BIT(0)
#define PCIE_REVISION_ID        BIT(0)
#define PCIE_CLASS_CODE         (0x60400 << 8)
#define PCIE_CONF_REG(regn)     (((regn) & GENMASK(7, 2)) | \
                                ((((regn) >> 8) & GENMASK(3, 0)) << 24))
#define PCIE_CONF_FUN(fun)      (((fun) << 8) & GENMASK(10, 8))
#define PCIE_CONF_DEV(dev)      (((dev) << 11) & GENMASK(15, 11))
#define PCIE_CONF_BUS(bus)      (((bus) << 16) & GENMASK(23, 16))
#define PCIE_CONF_ADDR(regn, fun, dev, bus) \
        (PCIE_CONF_REG(regn) | PCIE_CONF_FUN(fun) | \
         PCIE_CONF_DEV(dev) | PCIE_CONF_BUS(bus))

/* MediaTek specific configuration registers */
#define PCIE_FTS_NUM            0x70c
#define PCIE_FTS_NUM_MASK       GENMASK(15, 8)
#define PCIE_FTS_NUM_L0(x)      ((x) & 0xff << 8)

#define PCIE_FC_CREDIT          0x73c
#define PCIE_FC_CREDIT_MASK     (GENMASK(31, 31) | GENMASK(28, 16))
#define PCIE_FC_CREDIT_VAL(x)   ((x) << 16)

/* PCIe V2 share registers */
#define PCIE_SYS_CFG_V2         0x0
#define PCIE_CSR_LTSSM_EN(x)    BIT(0 + (x) * 8)
#define PCIE_CSR_ASPM_L1_EN(x)  BIT(1 + (x) * 8)

/* PCIe V2 per-port registers */
#define PCIE_MSI_VECTOR         0x0c0

#define PCIE_CONF_VEND_ID       0x100
#define PCIE_CONF_DEVICE_ID     0x102
#define PCIE_CONF_CLASS_ID      0x106

#define PCIE_INT_MASK           0x420
#define INTX_MASK               GENMASK(19, 16)
#define INTX_SHIFT              16
#define PCIE_INT_STATUS         0x424
#define MSI_STATUS              BIT(23)
#define PCIE_IMSI_STATUS        0x42c
#define PCIE_IMSI_ADDR          0x430
#define MSI_MASK                BIT(23)
#define MTK_MSI_IRQS_NUM        32

#define PCIE_AHB_TRANS_BASE0_L  0x438
#define PCIE_AHB_TRANS_BASE0_H  0x43c
#define AHB2PCIE_SIZE(x)        ((x) & GENMASK(4, 0))
#define PCIE_AXI_WINDOW0        0x448
#define WIN_ENABLE              BIT(7)
/*
 * Define PCIe to AHB window size as 2^33 to support max 8GB address space
 * translate, support least 4GB DRAM size access from EP DMA(physical DRAM
 * start from 0x40000000).
 */
#define PCIE2AHB_SIZE   0x21

/* PCIe V2 configuration transaction header */
#define PCIE_CFG_HEADER0        0x460
#define PCIE_CFG_HEADER1        0x464
#define PCIE_CFG_HEADER2        0x468
#define PCIE_CFG_WDATA          0x470
#define PCIE_APP_TLP_REQ        0x488
#define PCIE_CFG_RDATA          0x48c
#define APP_CFG_REQ             BIT(0)
#define APP_CPL_STATUS          GENMASK(7, 5)

#define CFG_WRRD_TYPE_0         4
#define CFG_WR_FMT              2
#define CFG_RD_FMT              0

#define CFG_DW0_LENGTH(length)  ((length) & GENMASK(9, 0))
#define CFG_DW0_TYPE(type)      (((type) << 24) & GENMASK(28, 24))
#define CFG_DW0_FMT(fmt)        (((fmt) << 29) & GENMASK(31, 29))
#define CFG_DW2_REGN(regn)      ((regn) & GENMASK(11, 2))
#define CFG_DW2_FUN(fun)        (((fun) << 16) & GENMASK(18, 16))
#define CFG_DW2_DEV(dev)        (((dev) << 19) & GENMASK(23, 19))
#define CFG_DW2_BUS(bus)        (((bus) << 24) & GENMASK(31, 24))
#define CFG_HEADER_DW0(type, fmt) \
        (CFG_DW0_LENGTH(1) | CFG_DW0_TYPE(type) | CFG_DW0_FMT(fmt))
#define CFG_HEADER_DW1(where, size) \
        (GENMASK(((size) - 1), 0) << ((where) & 0x3))
#define CFG_HEADER_DW2(regn, fun, dev, bus) \
        (CFG_DW2_REGN(regn) | CFG_DW2_FUN(fun) | \
        CFG_DW2_DEV(dev) | CFG_DW2_BUS(bus))

#define PCIE_RST_CTRL           0x510
#define PCIE_PHY_RSTB           BIT(0)
#define PCIE_PIPE_SRSTB         BIT(1)
#define PCIE_MAC_SRSTB          BIT(2)
#define PCIE_CRSTB              BIT(3)
#define PCIE_PERSTB             BIT(8)
#define PCIE_LINKDOWN_RST_EN    GENMASK(15, 13)
#define PCIE_LINK_STATUS_V2     0x804
#define PCIE_PORT_LINKUP_V2     BIT(10)

struct mtk_pcie_port;

/**
 * enum mtk_pcie_quirks - MTK PCIe quirks
 * @MTK_PCIE_FIX_CLASS_ID: host's class ID needed to be fixed
 * @MTK_PCIE_FIX_DEVICE_ID: host's device ID needed to be fixed
 * @MTK_PCIE_NO_MSI: Bridge has no MSI support, and relies on an external block
 * @MTK_PCIE_SKIP_RSTB: Skip calling RSTB bits on PCIe probe
 */
enum mtk_pcie_quirks {
        MTK_PCIE_FIX_CLASS_ID = BIT(0),
        MTK_PCIE_FIX_DEVICE_ID = BIT(1),
        MTK_PCIE_NO_MSI = BIT(2),
        MTK_PCIE_SKIP_RSTB = BIT(3),
};

/**
 * struct mtk_pcie_soc - differentiate between host generations
 * @device_id: device ID which this host need to be fixed
 * @ops: pointer to configuration access functions
 * @startup: pointer to controller setting functions
 * @setup_irq: pointer to initialize IRQ functions
 * @quirks: PCIe device quirks.
 */
struct mtk_pcie_soc {
        unsigned int device_id;
        struct pci_ops *ops;
        int (*startup)(struct mtk_pcie_port *port);
        int (*setup_irq)(struct mtk_pcie_port *port, struct device_node *node);
        enum mtk_pcie_quirks quirks;
};

/**
 * struct mtk_pcie_port - PCIe port information
 * @base: IO mapped register base
 * @list: port list
 * @pcie: pointer to PCIe host info
 * @reset: pointer to port reset control
 * @sys_ck: pointer to transaction/data link layer clock
 * @ahb_ck: pointer to AHB slave interface operating clock for CSR access
 *          and RC initiated MMIO access
 * @axi_ck: pointer to application layer MMIO channel operating clock
 * @aux_ck: pointer to pe2_mac_bridge and pe2_mac_core operating clock
 *          when pcie_mac_ck/pcie_pipe_ck is turned off
 * @obff_ck: pointer to OBFF functional block operating clock
 * @pipe_ck: pointer to LTSSM and PHY/MAC layer operating clock
 * @phy: pointer to PHY control block
 * @slot: port slot
 * @irq: GIC irq
 * @irq_domain: legacy INTx IRQ domain
 * @inner_domain: inner IRQ domain
 * @lock: protect the msi_irq_in_use bitmap
 * @msi_irq_in_use: bit map for assigned MSI IRQ
 */
struct mtk_pcie_port {
        void __iomem *base;
        struct list_head list;
        struct mtk_pcie *pcie;
        struct reset_control *reset;
        struct clk *sys_ck;
        struct clk *ahb_ck;
        struct clk *axi_ck;
        struct clk *aux_ck;
        struct clk *obff_ck;
        struct clk *pipe_ck;
        struct phy *phy;
        u32 slot;
        int irq;
        struct irq_domain *irq_domain;
        struct irq_domain *inner_domain;
        struct mutex lock;
        DECLARE_BITMAP(msi_irq_in_use, MTK_MSI_IRQS_NUM);
};

/**
 * struct mtk_pcie - PCIe host information
 * @dev: pointer to PCIe device
 * @base: IO mapped register base
 * @cfg: IO mapped register map for PCIe config
 * @free_ck: free-run reference clock
 * @ports: pointer to PCIe port information
 * @soc: pointer to SoC-dependent operations
 */
struct mtk_pcie {
        struct device *dev;
        void __iomem *base;
        struct regmap *cfg;
        struct clk *free_ck;

        struct list_head ports;
        const struct mtk_pcie_soc *soc;
};

static void mtk_pcie_subsys_powerdown(struct mtk_pcie *pcie)
{
        struct device *dev = pcie->dev;

        clk_disable_unprepare(pcie->free_ck);

        pm_runtime_put_sync(dev);
        pm_runtime_disable(dev);
}

static void mtk_pcie_port_free(struct mtk_pcie_port *port)
{
        struct mtk_pcie *pcie = port->pcie;
        struct device *dev = pcie->dev;

        devm_iounmap(dev, port->base);
        list_del(&port->list);
        devm_kfree(dev, port);
}

static void mtk_pcie_put_resources(struct mtk_pcie *pcie)
{
        struct mtk_pcie_port *port, *tmp;

        list_for_each_entry_safe(port, tmp, &pcie->ports, list) {
                phy_power_off(port->phy);
                phy_exit(port->phy);
                clk_disable_unprepare(port->pipe_ck);
                clk_disable_unprepare(port->obff_ck);
                clk_disable_unprepare(port->axi_ck);
                clk_disable_unprepare(port->aux_ck);
                clk_disable_unprepare(port->ahb_ck);
                clk_disable_unprepare(port->sys_ck);
                mtk_pcie_port_free(port);
        }

        mtk_pcie_subsys_powerdown(pcie);
}

static int mtk_pcie_check_cfg_cpld(struct mtk_pcie_port *port)
{
        u32 val;
        int err;

        err = readl_poll_timeout_atomic(port->base + PCIE_APP_TLP_REQ, val,
                                        !(val & APP_CFG_REQ), 10,
                                        100 * USEC_PER_MSEC);
        if (err)
                return PCIBIOS_SET_FAILED;

        if (readl(port->base + PCIE_APP_TLP_REQ) & APP_CPL_STATUS)
                return PCIBIOS_SET_FAILED;

        return PCIBIOS_SUCCESSFUL;
}

static int mtk_pcie_hw_rd_cfg(struct mtk_pcie_port *port, u32 bus, u32 devfn,
                              int where, int size, u32 *val)
{
        u32 tmp;

        /* Write PCIe configuration transaction header for Cfgrd */
        writel(CFG_HEADER_DW0(CFG_WRRD_TYPE_0, CFG_RD_FMT),
               port->base + PCIE_CFG_HEADER0);
        writel(CFG_HEADER_DW1(where, size), port->base + PCIE_CFG_HEADER1);
        writel(CFG_HEADER_DW2(where, PCI_FUNC(devfn), PCI_SLOT(devfn), bus),
               port->base + PCIE_CFG_HEADER2);

        /* Trigger h/w to transmit Cfgrd TLP */
        tmp = readl(port->base + PCIE_APP_TLP_REQ);
        tmp |= APP_CFG_REQ;
        writel(tmp, port->base + PCIE_APP_TLP_REQ);

        /* Check completion status */
        if (mtk_pcie_check_cfg_cpld(port))
                return PCIBIOS_SET_FAILED;

        /* Read cpld payload of Cfgrd */
        *val = readl(port->base + PCIE_CFG_RDATA);

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

        return PCIBIOS_SUCCESSFUL;
}

static int mtk_pcie_hw_wr_cfg(struct mtk_pcie_port *port, u32 bus, u32 devfn,
                              int where, int size, u32 val)
{
        /* Write PCIe configuration transaction header for Cfgwr */
        writel(CFG_HEADER_DW0(CFG_WRRD_TYPE_0, CFG_WR_FMT),
               port->base + PCIE_CFG_HEADER0);
        writel(CFG_HEADER_DW1(where, size), port->base + PCIE_CFG_HEADER1);
        writel(CFG_HEADER_DW2(where, PCI_FUNC(devfn), PCI_SLOT(devfn), bus),
               port->base + PCIE_CFG_HEADER2);

        /* Write Cfgwr data */
        val = val << 8 * (where & 3);
        writel(val, port->base + PCIE_CFG_WDATA);

        /* Trigger h/w to transmit Cfgwr TLP */
        val = readl(port->base + PCIE_APP_TLP_REQ);
        val |= APP_CFG_REQ;
        writel(val, port->base + PCIE_APP_TLP_REQ);

        /* Check completion status */
        return mtk_pcie_check_cfg_cpld(port);
}

static struct mtk_pcie_port *mtk_pcie_find_port(struct pci_bus *bus,
                                                unsigned int devfn)
{
        struct mtk_pcie *pcie = bus->sysdata;
        struct mtk_pcie_port *port;
        struct pci_dev *dev = NULL;

        /*
         * Walk the bus hierarchy to get the devfn value
         * of the port in the root bus.
         */
        while (bus && bus->number) {
                dev = bus->self;
                bus = dev->bus;
                devfn = dev->devfn;
        }

        list_for_each_entry(port, &pcie->ports, list)
                if (port->slot == PCI_SLOT(devfn))
                        return port;

        return NULL;
}

static int mtk_pcie_config_read(struct pci_bus *bus, unsigned int devfn,
                                int where, int size, u32 *val)
{
        struct mtk_pcie_port *port;
        u32 bn = bus->number;

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

        return mtk_pcie_hw_rd_cfg(port, bn, devfn, where, size, val);
}

static int mtk_pcie_config_write(struct pci_bus *bus, unsigned int devfn,
                                 int where, int size, u32 val)
{
        struct mtk_pcie_port *port;
        u32 bn = bus->number;

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

        return mtk_pcie_hw_wr_cfg(port, bn, devfn, where, size, val);
}

static struct pci_ops mtk_pcie_ops_v2 = {
        .read  = mtk_pcie_config_read,
        .write = mtk_pcie_config_write,
};

static void mtk_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
{
        struct mtk_pcie_port *port = irq_data_get_irq_chip_data(data);
        phys_addr_t addr;

        /* MT2712/MT7622 only support 32-bit MSI addresses */
        addr = virt_to_phys(port->base + PCIE_MSI_VECTOR);
        msg->address_hi = 0;
        msg->address_lo = lower_32_bits(addr);

        msg->data = data->hwirq;

        dev_dbg(port->pcie->dev, "msi#%d address_hi %#x address_lo %#x\n",
                (int)data->hwirq, msg->address_hi, msg->address_lo);
}

static void mtk_msi_ack_irq(struct irq_data *data)
{
        struct mtk_pcie_port *port = irq_data_get_irq_chip_data(data);
        u32 hwirq = data->hwirq;

        writel(1 << hwirq, port->base + PCIE_IMSI_STATUS);
}

static struct irq_chip mtk_msi_bottom_irq_chip = {
        .name                   = "MTK MSI",
        .irq_compose_msi_msg    = mtk_compose_msi_msg,
        .irq_ack                = mtk_msi_ack_irq,
};

static int mtk_pcie_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
                                     unsigned int nr_irqs, void *args)
{
        struct mtk_pcie_port *port = domain->host_data;
        unsigned long bit;

        WARN_ON(nr_irqs != 1);
        mutex_lock(&port->lock);

        bit = find_first_zero_bit(port->msi_irq_in_use, MTK_MSI_IRQS_NUM);
        if (bit >= MTK_MSI_IRQS_NUM) {
                mutex_unlock(&port->lock);
                return -ENOSPC;
        }

        __set_bit(bit, port->msi_irq_in_use);

        mutex_unlock(&port->lock);

        irq_domain_set_info(domain, virq, bit, &mtk_msi_bottom_irq_chip,
                            domain->host_data, handle_edge_irq,
                            NULL, NULL);

        return 0;
}

static void mtk_pcie_irq_domain_free(struct irq_domain *domain,
                                     unsigned int virq, unsigned int nr_irqs)
{
        struct irq_data *d = irq_domain_get_irq_data(domain, virq);
        struct mtk_pcie_port *port = irq_data_get_irq_chip_data(d);

        mutex_lock(&port->lock);

        if (!test_bit(d->hwirq, port->msi_irq_in_use))
                dev_err(port->pcie->dev, "trying to free unused MSI#%lu\n",
                        d->hwirq);
        else
                __clear_bit(d->hwirq, port->msi_irq_in_use);

        mutex_unlock(&port->lock);

        irq_domain_free_irqs_parent(domain, virq, nr_irqs);
}

static const struct irq_domain_ops msi_domain_ops = {
        .alloc  = mtk_pcie_irq_domain_alloc,
        .free   = mtk_pcie_irq_domain_free,
};

#define MTK_MSI_FLAGS_REQUIRED (MSI_FLAG_USE_DEF_DOM_OPS        | \
                                MSI_FLAG_USE_DEF_CHIP_OPS       | \
                                MSI_FLAG_NO_AFFINITY)

#define MTK_MSI_FLAGS_SUPPORTED (MSI_GENERIC_FLAGS_MASK         | \
                                 MSI_FLAG_PCI_MSIX)

static const struct msi_parent_ops mtk_msi_parent_ops = {
        .required_flags         = MTK_MSI_FLAGS_REQUIRED,
        .supported_flags        = MTK_MSI_FLAGS_SUPPORTED,
        .bus_select_token       = DOMAIN_BUS_PCI_MSI,
        .chip_flags             = MSI_CHIP_FLAG_SET_ACK,
        .prefix                 = "MTK-",
        .init_dev_msi_info      = msi_lib_init_dev_msi_info,
};

static int mtk_pcie_allocate_msi_domains(struct mtk_pcie_port *port)
{
        mutex_init(&port->lock);

        struct irq_domain_info info = {
                .fwnode         = dev_fwnode(port->pcie->dev),
                .ops            = &msi_domain_ops,
                .host_data      = port,
                .size           = MTK_MSI_IRQS_NUM,
        };

        port->inner_domain = msi_create_parent_irq_domain(&info, &mtk_msi_parent_ops);
        if (!port->inner_domain) {
                dev_err(port->pcie->dev, "failed to create IRQ domain\n");
                return -ENOMEM;
        }

        return 0;
}

static void mtk_pcie_enable_msi(struct mtk_pcie_port *port)
{
        u32 val;
        phys_addr_t msg_addr;

        msg_addr = virt_to_phys(port->base + PCIE_MSI_VECTOR);
        val = lower_32_bits(msg_addr);
        writel(val, port->base + PCIE_IMSI_ADDR);

        val = readl(port->base + PCIE_INT_MASK);
        val &= ~MSI_MASK;
        writel(val, port->base + PCIE_INT_MASK);
}

static void mtk_pcie_irq_teardown(struct mtk_pcie *pcie)
{
        struct mtk_pcie_port *port, *tmp;

        list_for_each_entry_safe(port, tmp, &pcie->ports, list) {
                irq_set_chained_handler_and_data(port->irq, NULL, NULL);

                if (port->irq_domain)
                        irq_domain_remove(port->irq_domain);

                if (IS_ENABLED(CONFIG_PCI_MSI)) {
                        if (port->inner_domain)
                                irq_domain_remove(port->inner_domain);
                }

                irq_dispose_mapping(port->irq);
        }
}

static int mtk_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 = mtk_pcie_intx_map,
};

static int mtk_pcie_init_irq_domain(struct mtk_pcie_port *port,
                                    struct device_node *node)
{
        struct device *dev = port->pcie->dev;
        struct device_node *pcie_intc_node;
        int ret;

        /* Setup INTx */
        pcie_intc_node = of_get_next_child(node, NULL);
        if (!pcie_intc_node) {
                dev_err(dev, "no PCIe Intc node found\n");
                return -ENODEV;
        }

        port->irq_domain = irq_domain_create_linear(of_fwnode_handle(pcie_intc_node), PCI_NUM_INTX,
                                                    &intx_domain_ops, port);
        of_node_put(pcie_intc_node);
        if (!port->irq_domain) {
                dev_err(dev, "failed to get INTx IRQ domain\n");
                return -ENODEV;
        }

        if (IS_ENABLED(CONFIG_PCI_MSI)) {
                ret = mtk_pcie_allocate_msi_domains(port);
                if (ret) {
                        irq_domain_remove(port->irq_domain);
                        return ret;
                }
        }

        return 0;
}

static void mtk_pcie_intr_handler(struct irq_desc *desc)
{
        struct mtk_pcie_port *port = irq_desc_get_handler_data(desc);
        struct irq_chip *irqchip = irq_desc_get_chip(desc);
        unsigned long status;
        u32 bit = INTX_SHIFT;

        chained_irq_enter(irqchip, desc);

        status = readl(port->base + PCIE_INT_STATUS);
        if (status & INTX_MASK) {
                for_each_set_bit_from(bit, &status, PCI_NUM_INTX + INTX_SHIFT) {
                        /* Clear the INTx */
                        writel(1 << bit, port->base + PCIE_INT_STATUS);
                        generic_handle_domain_irq(port->irq_domain,
                                                  bit - INTX_SHIFT);
                }
        }

        if (IS_ENABLED(CONFIG_PCI_MSI)) {
                if (status & MSI_STATUS){
                        unsigned long imsi_status;

                        /*
                         * The interrupt status can be cleared even if the
                         * MSI status remains pending. As such, given the
                         * edge-triggered interrupt type, its status should
                         * be cleared before being dispatched to the
                         * handler of the underlying device.
                         */
                        writel(MSI_STATUS, port->base + PCIE_INT_STATUS);
                        while ((imsi_status = readl(port->base + PCIE_IMSI_STATUS))) {
                                for_each_set_bit(bit, &imsi_status, MTK_MSI_IRQS_NUM)
                                        generic_handle_domain_irq(port->inner_domain, bit);
                        }
                }
        }

        chained_irq_exit(irqchip, desc);
}

static int mtk_pcie_setup_irq(struct mtk_pcie_port *port,
                              struct device_node *node)
{
        struct mtk_pcie *pcie = port->pcie;
        struct device *dev = pcie->dev;
        struct platform_device *pdev = to_platform_device(dev);
        int err;

        err = mtk_pcie_init_irq_domain(port, node);
        if (err) {
                dev_err(dev, "failed to init PCIe IRQ domain\n");
                return err;
        }

        if (of_property_present(dev->of_node, "interrupt-names"))
                port->irq = platform_get_irq_byname(pdev, "pcie_irq");
        else
                port->irq = platform_get_irq(pdev, port->slot);

        if (port->irq < 0)
                return port->irq;

        irq_set_chained_handler_and_data(port->irq,
                                         mtk_pcie_intr_handler, port);

        return 0;
}

static int mtk_pcie_startup_port_v2(struct mtk_pcie_port *port)
{
        struct mtk_pcie *pcie = port->pcie;
        struct pci_host_bridge *host = pci_host_bridge_from_priv(pcie);
        struct resource *mem = NULL;
        struct resource_entry *entry;
        const struct mtk_pcie_soc *soc = port->pcie->soc;
        u32 val;
        int err;

        entry = resource_list_first_type(&host->windows, IORESOURCE_MEM);
        if (entry)
                mem = entry->res;
        if (!mem)
                return -EINVAL;

        /* MT7622 platforms need to enable LTSSM and ASPM from PCIe subsys */
        if (pcie->base) {
                val = readl(pcie->base + PCIE_SYS_CFG_V2);
                val |= PCIE_CSR_LTSSM_EN(port->slot) |
                       PCIE_CSR_ASPM_L1_EN(port->slot);
                writel(val, pcie->base + PCIE_SYS_CFG_V2);
        } else if (pcie->cfg) {
                val = PCIE_CSR_LTSSM_EN(port->slot) |
                      PCIE_CSR_ASPM_L1_EN(port->slot);
                regmap_update_bits(pcie->cfg, PCIE_SYS_CFG_V2, val, val);
        }

        if (!(soc->quirks & MTK_PCIE_SKIP_RSTB)) {
                /* Assert all reset signals */
                writel(0, port->base + PCIE_RST_CTRL);

                /*
                 * Enable PCIe link down reset, if link status changed from
                 * link up to link down, this will reset MAC control registers
                 * and configuration space.
                 */
                writel(PCIE_LINKDOWN_RST_EN, port->base + PCIE_RST_CTRL);

                msleep(PCIE_T_PVPERL_MS);

                /* De-assert PHY, PE, PIPE, MAC and configuration reset */
                val = readl(port->base + PCIE_RST_CTRL);
                val |= PCIE_PHY_RSTB | PCIE_PERSTB | PCIE_PIPE_SRSTB |
                       PCIE_MAC_SRSTB | PCIE_CRSTB;
                writel(val, port->base + PCIE_RST_CTRL);
        }

        /* Set up vendor ID and class code */
        if (soc->quirks & MTK_PCIE_FIX_CLASS_ID) {
                val = PCI_VENDOR_ID_MEDIATEK;
                writew(val, port->base + PCIE_CONF_VEND_ID);

                val = PCI_CLASS_BRIDGE_PCI;
                writew(val, port->base + PCIE_CONF_CLASS_ID);
        }

        if (soc->quirks & MTK_PCIE_FIX_DEVICE_ID)
                writew(soc->device_id, port->base + PCIE_CONF_DEVICE_ID);

        /* 100ms timeout value should be enough for Gen1/2 training */
        err = readl_poll_timeout(port->base + PCIE_LINK_STATUS_V2, val,
                                 !!(val & PCIE_PORT_LINKUP_V2), 20,
                                 100 * USEC_PER_MSEC);
        if (err)
                return -ETIMEDOUT;

        /* Set INTx mask */
        val = readl(port->base + PCIE_INT_MASK);
        val &= ~INTX_MASK;
        writel(val, port->base + PCIE_INT_MASK);

        if (IS_ENABLED(CONFIG_PCI_MSI))
                mtk_pcie_enable_msi(port);

        /* Set AHB to PCIe translation windows */
        val = lower_32_bits(mem->start) |
              AHB2PCIE_SIZE(fls(resource_size(mem)));
        writel(val, port->base + PCIE_AHB_TRANS_BASE0_L);

        val = upper_32_bits(mem->start);
        writel(val, port->base + PCIE_AHB_TRANS_BASE0_H);

        /* Set PCIe to AXI translation memory space.*/
        val = PCIE2AHB_SIZE | WIN_ENABLE;
        writel(val, port->base + PCIE_AXI_WINDOW0);

        return 0;
}

static void __iomem *mtk_pcie_map_bus(struct pci_bus *bus,
                                      unsigned int devfn, int where)
{
        struct mtk_pcie *pcie = bus->sysdata;

        writel(PCIE_CONF_ADDR(where, PCI_FUNC(devfn), PCI_SLOT(devfn),
                              bus->number), pcie->base + PCIE_CFG_ADDR);

        return pcie->base + PCIE_CFG_DATA + (where & 3);
}

static struct pci_ops mtk_pcie_ops = {
        .map_bus = mtk_pcie_map_bus,
        .read  = pci_generic_config_read,
        .write = pci_generic_config_write,
};

static int mtk_pcie_startup_port(struct mtk_pcie_port *port)
{
        struct mtk_pcie *pcie = port->pcie;
        u32 func = PCI_FUNC(port->slot);
        u32 slot = PCI_SLOT(port->slot << 3);
        u32 val;
        int err;

        /* assert port PERST_N */
        val = readl(pcie->base + PCIE_SYS_CFG);
        val |= PCIE_PORT_PERST(port->slot);
        writel(val, pcie->base + PCIE_SYS_CFG);

        /* de-assert port PERST_N */
        val = readl(pcie->base + PCIE_SYS_CFG);
        val &= ~PCIE_PORT_PERST(port->slot);
        writel(val, pcie->base + PCIE_SYS_CFG);

        /* 100ms timeout value should be enough for Gen1/2 training */
        err = readl_poll_timeout(port->base + PCIE_LINK_STATUS, val,
                                 !!(val & PCIE_PORT_LINKUP), 20,
                                 100 * USEC_PER_MSEC);
        if (err)
                return -ETIMEDOUT;

        /* enable interrupt */
        val = readl(pcie->base + PCIE_INT_ENABLE);
        val |= PCIE_PORT_INT_EN(port->slot);
        writel(val, pcie->base + PCIE_INT_ENABLE);

        /* map to all DDR region. We need to set it before cfg operation. */
        writel(PCIE_BAR_MAP_MAX | PCIE_BAR_ENABLE,
               port->base + PCIE_BAR0_SETUP);

        /* configure class code and revision ID */
        writel(PCIE_CLASS_CODE | PCIE_REVISION_ID, port->base + PCIE_CLASS);

        /* configure FC credit */
        writel(PCIE_CONF_ADDR(PCIE_FC_CREDIT, func, slot, 0),
               pcie->base + PCIE_CFG_ADDR);
        val = readl(pcie->base + PCIE_CFG_DATA);
        val &= ~PCIE_FC_CREDIT_MASK;
        val |= PCIE_FC_CREDIT_VAL(0x806c);
        writel(PCIE_CONF_ADDR(PCIE_FC_CREDIT, func, slot, 0),
               pcie->base + PCIE_CFG_ADDR);
        writel(val, pcie->base + PCIE_CFG_DATA);

        /* configure RC FTS number to 250 when it leaves L0s */
        writel(PCIE_CONF_ADDR(PCIE_FTS_NUM, func, slot, 0),
               pcie->base + PCIE_CFG_ADDR);
        val = readl(pcie->base + PCIE_CFG_DATA);
        val &= ~PCIE_FTS_NUM_MASK;
        val |= PCIE_FTS_NUM_L0(0x50);
        writel(PCIE_CONF_ADDR(PCIE_FTS_NUM, func, slot, 0),
               pcie->base + PCIE_CFG_ADDR);
        writel(val, pcie->base + PCIE_CFG_DATA);

        return 0;
}

static int mtk_pcie_startup_port_an7583(struct mtk_pcie_port *port)
{
        struct mtk_pcie *pcie = port->pcie;
        struct device *dev = pcie->dev;
        struct pci_host_bridge *host;
        struct resource_entry *entry;
        struct regmap *pbus_regmap;
        resource_size_t addr;
        u32 args[2], size;

        /*
         * Configure PBus base address and base address mask to allow
         * the hw to detect if a given address is accessible on PCIe
         * controller.
         */
        pbus_regmap = syscon_regmap_lookup_by_phandle_args(dev->of_node,
                                                           "mediatek,pbus-csr",
                                                           ARRAY_SIZE(args),
                                                           args);
        if (IS_ERR(pbus_regmap))
                return PTR_ERR(pbus_regmap);

        host = pci_host_bridge_from_priv(pcie);
        entry = resource_list_first_type(&host->windows, IORESOURCE_MEM);
        if (!entry)
                return -ENODEV;

        addr = entry->res->start - entry->offset;
        regmap_write(pbus_regmap, args[0], lower_32_bits(addr));
        size = lower_32_bits(resource_size(entry->res));
        regmap_write(pbus_regmap, args[1], GENMASK(31, __fls(size)));

        return mtk_pcie_startup_port_v2(port);
}

static void mtk_pcie_enable_port(struct mtk_pcie_port *port)
{
        struct mtk_pcie *pcie = port->pcie;
        struct device *dev = pcie->dev;
        int err;

        err = clk_prepare_enable(port->sys_ck);
        if (err) {
                dev_err(dev, "failed to enable sys_ck%d clock\n", port->slot);
                goto err_sys_clk;
        }

        err = clk_prepare_enable(port->ahb_ck);
        if (err) {
                dev_err(dev, "failed to enable ahb_ck%d\n", port->slot);
                goto err_ahb_clk;
        }

        err = clk_prepare_enable(port->aux_ck);
        if (err) {
                dev_err(dev, "failed to enable aux_ck%d\n", port->slot);
                goto err_aux_clk;
        }

        err = clk_prepare_enable(port->axi_ck);
        if (err) {
                dev_err(dev, "failed to enable axi_ck%d\n", port->slot);
                goto err_axi_clk;
        }

        err = clk_prepare_enable(port->obff_ck);
        if (err) {
                dev_err(dev, "failed to enable obff_ck%d\n", port->slot);
                goto err_obff_clk;
        }

        err = clk_prepare_enable(port->pipe_ck);
        if (err) {
                dev_err(dev, "failed to enable pipe_ck%d\n", port->slot);
                goto err_pipe_clk;
        }

        reset_control_assert(port->reset);
        reset_control_deassert(port->reset);

        err = phy_init(port->phy);
        if (err) {
                dev_err(dev, "failed to initialize port%d phy\n", port->slot);
                goto err_phy_init;
        }

        err = phy_power_on(port->phy);
        if (err) {
                dev_err(dev, "failed to power on port%d phy\n", port->slot);
                goto err_phy_on;
        }

        if (!pcie->soc->startup(port))
                return;

        dev_info(dev, "Port%d link down\n", port->slot);

        phy_power_off(port->phy);
err_phy_on:
        phy_exit(port->phy);
err_phy_init:
        clk_disable_unprepare(port->pipe_ck);
err_pipe_clk:
        clk_disable_unprepare(port->obff_ck);
err_obff_clk:
        clk_disable_unprepare(port->axi_ck);
err_axi_clk:
        clk_disable_unprepare(port->aux_ck);
err_aux_clk:
        clk_disable_unprepare(port->ahb_ck);
err_ahb_clk:
        clk_disable_unprepare(port->sys_ck);
err_sys_clk:
        mtk_pcie_port_free(port);
}

static int mtk_pcie_parse_port(struct mtk_pcie *pcie,
                               struct device_node *node,
                               int slot)
{
        struct mtk_pcie_port *port;
        struct device *dev = pcie->dev;
        struct platform_device *pdev = to_platform_device(dev);
        char name[10];
        int err;

        port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
        if (!port)
                return -ENOMEM;

        snprintf(name, sizeof(name), "port%d", slot);
        port->base = devm_platform_ioremap_resource_byname(pdev, name);
        if (IS_ERR(port->base)) {
                dev_err(dev, "failed to map port%d base\n", slot);
                return PTR_ERR(port->base);
        }

        snprintf(name, sizeof(name), "sys_ck%d", slot);
        port->sys_ck = devm_clk_get(dev, name);
        if (IS_ERR(port->sys_ck)) {
                dev_err(dev, "failed to get sys_ck%d clock\n", slot);
                return PTR_ERR(port->sys_ck);
        }

        /* sys_ck might be divided into the following parts in some chips */
        snprintf(name, sizeof(name), "ahb_ck%d", slot);
        port->ahb_ck = devm_clk_get_optional(dev, name);
        if (IS_ERR(port->ahb_ck))
                return PTR_ERR(port->ahb_ck);

        snprintf(name, sizeof(name), "axi_ck%d", slot);
        port->axi_ck = devm_clk_get_optional(dev, name);
        if (IS_ERR(port->axi_ck))
                return PTR_ERR(port->axi_ck);

        snprintf(name, sizeof(name), "aux_ck%d", slot);
        port->aux_ck = devm_clk_get_optional(dev, name);
        if (IS_ERR(port->aux_ck))
                return PTR_ERR(port->aux_ck);

        snprintf(name, sizeof(name), "obff_ck%d", slot);
        port->obff_ck = devm_clk_get_optional(dev, name);
        if (IS_ERR(port->obff_ck))
                return PTR_ERR(port->obff_ck);

        snprintf(name, sizeof(name), "pipe_ck%d", slot);
        port->pipe_ck = devm_clk_get_optional(dev, name);
        if (IS_ERR(port->pipe_ck))
                return PTR_ERR(port->pipe_ck);

        snprintf(name, sizeof(name), "pcie-rst%d", slot);
        port->reset = devm_reset_control_get_optional_exclusive(dev, name);
        if (PTR_ERR(port->reset) == -EPROBE_DEFER)
                return PTR_ERR(port->reset);

        /* some platforms may use default PHY setting */
        snprintf(name, sizeof(name), "pcie-phy%d", slot);
        port->phy = devm_phy_optional_get(dev, name);
        if (IS_ERR(port->phy))
                return PTR_ERR(port->phy);

        port->slot = slot;
        port->pcie = pcie;

        if (pcie->soc->setup_irq) {
                err = pcie->soc->setup_irq(port, node);
                if (err)
                        return err;
        }

        INIT_LIST_HEAD(&port->list);
        list_add_tail(&port->list, &pcie->ports);

        return 0;
}

static int mtk_pcie_subsys_powerup(struct mtk_pcie *pcie)
{
        struct device *dev = pcie->dev;
        struct platform_device *pdev = to_platform_device(dev);
        struct resource *regs;
        struct device_node *cfg_node;
        int err;

        /* get shared registers, which are optional */
        regs = platform_get_resource_byname(pdev, IORESOURCE_MEM, "subsys");
        if (regs) {
                pcie->base = devm_ioremap_resource(dev, regs);
                if (IS_ERR(pcie->base))
                        return PTR_ERR(pcie->base);
        }

        cfg_node = of_find_compatible_node(NULL, NULL,
                                           "mediatek,generic-pciecfg");
        if (cfg_node) {
                pcie->cfg = syscon_node_to_regmap(cfg_node);
                of_node_put(cfg_node);
                if (IS_ERR(pcie->cfg))
                        return PTR_ERR(pcie->cfg);
        }

        pcie->free_ck = devm_clk_get(dev, "free_ck");
        if (IS_ERR(pcie->free_ck)) {
                if (PTR_ERR(pcie->free_ck) == -EPROBE_DEFER)
                        return -EPROBE_DEFER;

                pcie->free_ck = NULL;
        }

        pm_runtime_enable(dev);
        pm_runtime_get_sync(dev);

        /* enable top level clock */
        err = clk_prepare_enable(pcie->free_ck);
        if (err) {
                dev_err(dev, "failed to enable free_ck\n");
                goto err_free_ck;
        }

        return 0;

err_free_ck:
        pm_runtime_put_sync(dev);
        pm_runtime_disable(dev);

        return err;
}

static int mtk_pcie_setup(struct mtk_pcie *pcie)
{
        struct device *dev = pcie->dev;
        struct device_node *node = dev->of_node;
        struct mtk_pcie_port *port, *tmp;
        int err, slot;

        slot = of_get_pci_domain_nr(dev->of_node);
        if (slot < 0) {
                for_each_available_child_of_node_scoped(node, child) {
                        err = of_pci_get_devfn(child);
                        if (err < 0)
                                return dev_err_probe(dev, err, "failed to get devfn\n");

                        slot = PCI_SLOT(err);

                        err = mtk_pcie_parse_port(pcie, child, slot);
                        if (err)
                                return err;
                }
        } else {
                err = mtk_pcie_parse_port(pcie, node, slot);
                if (err)
                        return err;
        }

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

        /* enable each port, and then check link status */
        list_for_each_entry_safe(port, tmp, &pcie->ports, list)
                mtk_pcie_enable_port(port);

        /* power down PCIe subsys if slots are all empty (link down) */
        if (list_empty(&pcie->ports))
                mtk_pcie_subsys_powerdown(pcie);

        return 0;
}

static int mtk_pcie_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct mtk_pcie *pcie;
        struct pci_host_bridge *host;
        int err;

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

        pcie = pci_host_bridge_priv(host);

        pcie->dev = dev;
        pcie->soc = of_device_get_match_data(dev);
        platform_set_drvdata(pdev, pcie);
        INIT_LIST_HEAD(&pcie->ports);

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

        host->ops = pcie->soc->ops;
        host->sysdata = pcie;
        host->msi_domain = !!(pcie->soc->quirks & MTK_PCIE_NO_MSI);

        err = pci_host_probe(host);
        if (err)
                goto put_resources;

        return 0;

put_resources:
        if (!list_empty(&pcie->ports))
                mtk_pcie_put_resources(pcie);

        return err;
}


static void mtk_pcie_free_resources(struct mtk_pcie *pcie)
{
        struct pci_host_bridge *host = pci_host_bridge_from_priv(pcie);
        struct list_head *windows = &host->windows;

        pci_free_resource_list(windows);
}

static void mtk_pcie_remove(struct platform_device *pdev)
{
        struct mtk_pcie *pcie = platform_get_drvdata(pdev);
        struct pci_host_bridge *host = pci_host_bridge_from_priv(pcie);

        pci_stop_root_bus(host->bus);
        pci_remove_root_bus(host->bus);
        mtk_pcie_free_resources(pcie);

        mtk_pcie_irq_teardown(pcie);

        mtk_pcie_put_resources(pcie);
}

static int mtk_pcie_suspend_noirq(struct device *dev)
{
        struct mtk_pcie *pcie = dev_get_drvdata(dev);
        struct mtk_pcie_port *port;

        if (list_empty(&pcie->ports))
                return 0;

        list_for_each_entry(port, &pcie->ports, list) {
                clk_disable_unprepare(port->pipe_ck);
                clk_disable_unprepare(port->obff_ck);
                clk_disable_unprepare(port->axi_ck);
                clk_disable_unprepare(port->aux_ck);
                clk_disable_unprepare(port->ahb_ck);
                clk_disable_unprepare(port->sys_ck);
                phy_power_off(port->phy);
                phy_exit(port->phy);
        }

        clk_disable_unprepare(pcie->free_ck);

        return 0;
}

static int mtk_pcie_resume_noirq(struct device *dev)
{
        struct mtk_pcie *pcie = dev_get_drvdata(dev);
        struct mtk_pcie_port *port, *tmp;

        if (list_empty(&pcie->ports))
                return 0;

        clk_prepare_enable(pcie->free_ck);

        list_for_each_entry_safe(port, tmp, &pcie->ports, list)
                mtk_pcie_enable_port(port);

        /* In case of EP was removed while system suspend. */
        if (list_empty(&pcie->ports))
                clk_disable_unprepare(pcie->free_ck);

        return 0;
}

static const struct dev_pm_ops mtk_pcie_pm_ops = {
        NOIRQ_SYSTEM_SLEEP_PM_OPS(mtk_pcie_suspend_noirq,
                                  mtk_pcie_resume_noirq)
};

static const struct mtk_pcie_soc mtk_pcie_soc_v1 = {
        .ops = &mtk_pcie_ops,
        .startup = mtk_pcie_startup_port,
        .quirks = MTK_PCIE_NO_MSI,
};

static const struct mtk_pcie_soc mtk_pcie_soc_mt2712 = {
        .ops = &mtk_pcie_ops_v2,
        .startup = mtk_pcie_startup_port_v2,
        .setup_irq = mtk_pcie_setup_irq,
};

static const struct mtk_pcie_soc mtk_pcie_soc_mt7622 = {
        .ops = &mtk_pcie_ops_v2,
        .startup = mtk_pcie_startup_port_v2,
        .setup_irq = mtk_pcie_setup_irq,
        .quirks = MTK_PCIE_FIX_CLASS_ID,
};

static const struct mtk_pcie_soc mtk_pcie_soc_an7583 = {
        .ops = &mtk_pcie_ops_v2,
        .startup = mtk_pcie_startup_port_an7583,
        .setup_irq = mtk_pcie_setup_irq,
        .quirks = MTK_PCIE_FIX_CLASS_ID | MTK_PCIE_SKIP_RSTB,
};

static const struct mtk_pcie_soc mtk_pcie_soc_mt7629 = {
        .device_id = PCI_DEVICE_ID_MEDIATEK_7629,
        .ops = &mtk_pcie_ops_v2,
        .startup = mtk_pcie_startup_port_v2,
        .setup_irq = mtk_pcie_setup_irq,
        .quirks = MTK_PCIE_FIX_CLASS_ID | MTK_PCIE_FIX_DEVICE_ID,
};

static const struct of_device_id mtk_pcie_ids[] = {
        { .compatible = "airoha,an7583-pcie", .data = &mtk_pcie_soc_an7583 },
        { .compatible = "mediatek,mt2701-pcie", .data = &mtk_pcie_soc_v1 },
        { .compatible = "mediatek,mt7623-pcie", .data = &mtk_pcie_soc_v1 },
        { .compatible = "mediatek,mt2712-pcie", .data = &mtk_pcie_soc_mt2712 },
        { .compatible = "mediatek,mt7622-pcie", .data = &mtk_pcie_soc_mt7622 },
        { .compatible = "mediatek,mt7629-pcie", .data = &mtk_pcie_soc_mt7629 },
        {},
};
MODULE_DEVICE_TABLE(of, mtk_pcie_ids);

static struct platform_driver mtk_pcie_driver = {
        .probe = mtk_pcie_probe,
        .remove = mtk_pcie_remove,
        .driver = {
                .name = "mtk-pcie",
                .of_match_table = mtk_pcie_ids,
                .suppress_bind_attrs = true,
                .pm = &mtk_pcie_pm_ops,
        },
};
module_platform_driver(mtk_pcie_driver);
MODULE_DESCRIPTION("MediaTek PCIe host controller driver");
MODULE_LICENSE("GPL v2");