// SPDX-License-Identifier: GPL-2.0
/*
 * Freescale i.MX6 PCI Express Root-Complex driver
 *
 * Copyright (C) 2013 Marek Vasut <marex@denx.de>
 *
 * Based on upstream Linux kernel driver:
 * pci-imx6.c:          Sean Cross <xobs@kosagi.com>
 * pcie-designware.c:   Jingoo Han <jg1.han@samsung.com>
 */

#include <common.h>
#include <init.h>
#include <pci.h>
#include <asm/arch/clock.h>
#include <asm/arch/iomux.h>
#include <asm/arch/crm_regs.h>
#include <asm/gpio.h>
#include <asm/io.h>
#include <dm.h>
#include <linux/sizes.h>
#include <errno.h>
#include <asm/arch/sys_proto.h>

#define PCI_ACCESS_READ  0
#define PCI_ACCESS_WRITE 1

#ifdef CONFIG_MX6SX
#define MX6_DBI_ADDR    0x08ffc000
#define MX6_IO_ADDR     0x08000000
#define MX6_MEM_ADDR    0x08100000
#define MX6_ROOT_ADDR   0x08f00000
#else
#define MX6_DBI_ADDR    0x01ffc000
#define MX6_IO_ADDR     0x01000000
#define MX6_MEM_ADDR    0x01100000
#define MX6_ROOT_ADDR   0x01f00000
#endif
#define MX6_DBI_SIZE    0x4000
#define MX6_IO_SIZE     0x100000
#define MX6_MEM_SIZE    0xe00000
#define MX6_ROOT_SIZE   0xfc000

/* PCIe Port Logic registers (memory-mapped) */
#define PL_OFFSET 0x700
#define PCIE_PL_PFLR (PL_OFFSET + 0x08)
#define PCIE_PL_PFLR_LINK_STATE_MASK            (0x3f << 16)
#define PCIE_PL_PFLR_FORCE_LINK                 (1 << 15)
#define PCIE_PHY_DEBUG_R0 (PL_OFFSET + 0x28)
#define PCIE_PHY_DEBUG_R1 (PL_OFFSET + 0x2c)
#define PCIE_PHY_DEBUG_R1_LINK_UP               (1 << 4)
#define PCIE_PHY_DEBUG_R1_LINK_IN_TRAINING      (1 << 29)

#define PCIE_PHY_CTRL (PL_OFFSET + 0x114)
#define PCIE_PHY_CTRL_DATA_LOC 0
#define PCIE_PHY_CTRL_CAP_ADR_LOC 16
#define PCIE_PHY_CTRL_CAP_DAT_LOC 17
#define PCIE_PHY_CTRL_WR_LOC 18
#define PCIE_PHY_CTRL_RD_LOC 19

#define PCIE_PHY_STAT (PL_OFFSET + 0x110)
#define PCIE_PHY_STAT_DATA_LOC 0
#define PCIE_PHY_STAT_ACK_LOC 16

/* PHY registers (not memory-mapped) */
#define PCIE_PHY_RX_ASIC_OUT 0x100D

#define PHY_RX_OVRD_IN_LO 0x1005
#define PHY_RX_OVRD_IN_LO_RX_DATA_EN (1 << 5)
#define PHY_RX_OVRD_IN_LO_RX_PLL_EN (1 << 3)

#define PCIE_PHY_PUP_REQ                (1 << 7)

/* iATU registers */
#define PCIE_ATU_VIEWPORT               0x900
#define PCIE_ATU_REGION_INBOUND         (0x1 << 31)
#define PCIE_ATU_REGION_OUTBOUND        (0x0 << 31)
#define PCIE_ATU_REGION_INDEX1          (0x1 << 0)
#define PCIE_ATU_REGION_INDEX0          (0x0 << 0)
#define PCIE_ATU_CR1                    0x904
#define PCIE_ATU_TYPE_MEM               (0x0 << 0)
#define PCIE_ATU_TYPE_IO                (0x2 << 0)
#define PCIE_ATU_TYPE_CFG0              (0x4 << 0)
#define PCIE_ATU_TYPE_CFG1              (0x5 << 0)
#define PCIE_ATU_CR2                    0x908
#define PCIE_ATU_ENABLE                 (0x1 << 31)
#define PCIE_ATU_BAR_MODE_ENABLE        (0x1 << 30)
#define PCIE_ATU_LOWER_BASE             0x90C
#define PCIE_ATU_UPPER_BASE             0x910
#define PCIE_ATU_LIMIT                  0x914
#define PCIE_ATU_LOWER_TARGET           0x918
#define PCIE_ATU_BUS(x)                 (((x) & 0xff) << 24)
#define PCIE_ATU_DEV(x)                 (((x) & 0x1f) << 19)
#define PCIE_ATU_FUNC(x)                (((x) & 0x7) << 16)
#define PCIE_ATU_UPPER_TARGET           0x91C

struct imx_pcie_priv {
        void __iomem            *dbi_base;
        void __iomem            *cfg_base;
};

/*
 * PHY access functions
 */
static int pcie_phy_poll_ack(void __iomem *dbi_base, int exp_val)
{
        u32 val;
        u32 max_iterations = 10;
        u32 wait_counter = 0;

        do {
                val = readl(dbi_base + PCIE_PHY_STAT);
                val = (val >> PCIE_PHY_STAT_ACK_LOC) & 0x1;
                wait_counter++;

                if (val == exp_val)
                        return 0;

                udelay(1);
        } while (wait_counter < max_iterations);

        return -ETIMEDOUT;
}

static int pcie_phy_wait_ack(void __iomem *dbi_base, int addr)
{
        u32 val;
        int ret;

        val = addr << PCIE_PHY_CTRL_DATA_LOC;
        writel(val, dbi_base + PCIE_PHY_CTRL);

        val |= (0x1 << PCIE_PHY_CTRL_CAP_ADR_LOC);
        writel(val, dbi_base + PCIE_PHY_CTRL);

        ret = pcie_phy_poll_ack(dbi_base, 1);
        if (ret)
                return ret;

        val = addr << PCIE_PHY_CTRL_DATA_LOC;
        writel(val, dbi_base + PCIE_PHY_CTRL);

        ret = pcie_phy_poll_ack(dbi_base, 0);
        if (ret)
                return ret;

        return 0;
}

/* Read from the 16-bit PCIe PHY control registers (not memory-mapped) */
static int pcie_phy_read(void __iomem *dbi_base, int addr , int *data)
{
        u32 val, phy_ctl;
        int ret;

        ret = pcie_phy_wait_ack(dbi_base, addr);
        if (ret)
                return ret;

        /* assert Read signal */
        phy_ctl = 0x1 << PCIE_PHY_CTRL_RD_LOC;
        writel(phy_ctl, dbi_base + PCIE_PHY_CTRL);

        ret = pcie_phy_poll_ack(dbi_base, 1);
        if (ret)
                return ret;

        val = readl(dbi_base + PCIE_PHY_STAT);
        *data = val & 0xffff;

        /* deassert Read signal */
        writel(0x00, dbi_base + PCIE_PHY_CTRL);

        ret = pcie_phy_poll_ack(dbi_base, 0);
        if (ret)
                return ret;

        return 0;
}

static int pcie_phy_write(void __iomem *dbi_base, int addr, int data)
{
        u32 var;
        int ret;

        /* write addr */
        /* cap addr */
        ret = pcie_phy_wait_ack(dbi_base, addr);
        if (ret)
                return ret;

        var = data << PCIE_PHY_CTRL_DATA_LOC;
        writel(var, dbi_base + PCIE_PHY_CTRL);

        /* capture data */
        var |= (0x1 << PCIE_PHY_CTRL_CAP_DAT_LOC);
        writel(var, dbi_base + PCIE_PHY_CTRL);

        ret = pcie_phy_poll_ack(dbi_base, 1);
        if (ret)
                return ret;

        /* deassert cap data */
        var = data << PCIE_PHY_CTRL_DATA_LOC;
        writel(var, dbi_base + PCIE_PHY_CTRL);

        /* wait for ack de-assertion */
        ret = pcie_phy_poll_ack(dbi_base, 0);
        if (ret)
                return ret;

        /* assert wr signal */
        var = 0x1 << PCIE_PHY_CTRL_WR_LOC;
        writel(var, dbi_base + PCIE_PHY_CTRL);

        /* wait for ack */
        ret = pcie_phy_poll_ack(dbi_base, 1);
        if (ret)
                return ret;

        /* deassert wr signal */
        var = data << PCIE_PHY_CTRL_DATA_LOC;
        writel(var, dbi_base + PCIE_PHY_CTRL);

        /* wait for ack de-assertion */
        ret = pcie_phy_poll_ack(dbi_base, 0);
        if (ret)
                return ret;

        writel(0x0, dbi_base + PCIE_PHY_CTRL);

        return 0;
}

static int imx6_pcie_link_up(struct imx_pcie_priv *priv)
{
        u32 rc, ltssm;
        int rx_valid, temp;

        /* link is debug bit 36, debug register 1 starts at bit 32 */
        rc = readl(priv->dbi_base + PCIE_PHY_DEBUG_R1);
        if ((rc & PCIE_PHY_DEBUG_R1_LINK_UP) &&
            !(rc & PCIE_PHY_DEBUG_R1_LINK_IN_TRAINING))
                return -EAGAIN;

        /*
         * From L0, initiate MAC entry to gen2 if EP/RC supports gen2.
         * Wait 2ms (LTSSM timeout is 24ms, PHY lock is ~5us in gen2).
         * If (MAC/LTSSM.state == Recovery.RcvrLock)
         * && (PHY/rx_valid==0) then pulse PHY/rx_reset. Transition
         * to gen2 is stuck
         */
        pcie_phy_read(priv->dbi_base, PCIE_PHY_RX_ASIC_OUT, &rx_valid);
        ltssm = readl(priv->dbi_base + PCIE_PHY_DEBUG_R0) & 0x3F;

        if (rx_valid & 0x01)
                return 0;

        if (ltssm != 0x0d)
                return 0;

        printf("transition to gen2 is stuck, reset PHY!\n");

        pcie_phy_read(priv->dbi_base, PHY_RX_OVRD_IN_LO, &temp);
        temp |= (PHY_RX_OVRD_IN_LO_RX_DATA_EN | PHY_RX_OVRD_IN_LO_RX_PLL_EN);
        pcie_phy_write(priv->dbi_base, PHY_RX_OVRD_IN_LO, temp);

        udelay(3000);

        pcie_phy_read(priv->dbi_base, PHY_RX_OVRD_IN_LO, &temp);
        temp &= ~(PHY_RX_OVRD_IN_LO_RX_DATA_EN | PHY_RX_OVRD_IN_LO_RX_PLL_EN);
        pcie_phy_write(priv->dbi_base, PHY_RX_OVRD_IN_LO, temp);

        return 0;
}

/*
 * iATU region setup
 */
static int imx_pcie_regions_setup(struct imx_pcie_priv *priv)
{
        /*
         * i.MX6 defines 16MB in the AXI address map for PCIe.
         *
         * That address space excepted the pcie registers is
         * split and defined into different regions by iATU,
         * with sizes and offsets as follows:
         *
         * 0x0100_0000 --- 0x010F_FFFF 1MB IORESOURCE_IO
         * 0x0110_0000 --- 0x01EF_FFFF 14MB IORESOURCE_MEM
         * 0x01F0_0000 --- 0x01FF_FFFF 1MB Cfg + Registers
         */

        /* CMD reg:I/O space, MEM space, and Bus Master Enable */
        setbits_le32(priv->dbi_base + PCI_COMMAND,
                     PCI_COMMAND_IO | PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER);

        /* Set the CLASS_REV of RC CFG header to PCI_CLASS_BRIDGE_PCI */
        setbits_le32(priv->dbi_base + PCI_CLASS_REVISION,
                     PCI_CLASS_BRIDGE_PCI << 16);

        /* Region #0 is used for Outbound CFG space access. */
        writel(0, priv->dbi_base + PCIE_ATU_VIEWPORT);

        writel(lower_32_bits((uintptr_t)priv->cfg_base),
               priv->dbi_base + PCIE_ATU_LOWER_BASE);
        writel(upper_32_bits((uintptr_t)priv->cfg_base),
               priv->dbi_base + PCIE_ATU_UPPER_BASE);
        writel(lower_32_bits((uintptr_t)priv->cfg_base + MX6_ROOT_SIZE),
               priv->dbi_base + PCIE_ATU_LIMIT);

        writel(0, priv->dbi_base + PCIE_ATU_LOWER_TARGET);
        writel(0, priv->dbi_base + PCIE_ATU_UPPER_TARGET);
        writel(PCIE_ATU_TYPE_CFG0, priv->dbi_base + PCIE_ATU_CR1);
        writel(PCIE_ATU_ENABLE, priv->dbi_base + PCIE_ATU_CR2);

        return 0;
}

/*
 * PCI Express accessors
 */
static void __iomem *get_bus_address(struct imx_pcie_priv *priv,
                                     pci_dev_t d, int where)
{
        void __iomem *va_address;

        /* Reconfigure Region #0 */
        writel(0, priv->dbi_base + PCIE_ATU_VIEWPORT);

        if (PCI_BUS(d) < 2)
                writel(PCIE_ATU_TYPE_CFG0, priv->dbi_base + PCIE_ATU_CR1);
        else
                writel(PCIE_ATU_TYPE_CFG1, priv->dbi_base + PCIE_ATU_CR1);

        if (PCI_BUS(d) == 0) {
                va_address = priv->dbi_base;
        } else {
                writel(d << 8, priv->dbi_base + PCIE_ATU_LOWER_TARGET);
                va_address = priv->cfg_base;
        }

        va_address += (where & ~0x3);

        return va_address;
}

static int imx_pcie_addr_valid(pci_dev_t d)
{
        if ((PCI_BUS(d) == 0) && (PCI_DEV(d) > 1))
                return -EINVAL;
        if ((PCI_BUS(d) == 1) && (PCI_DEV(d) > 0))
                return -EINVAL;
        return 0;
}

/*
 * Replace the original ARM DABT handler with a simple jump-back one.
 *
 * The problem here is that if we have a PCIe bridge attached to this PCIe
 * controller, but no PCIe device is connected to the bridges' downstream
 * port, the attempt to read/write from/to the config space will produce
 * a DABT. This is a behavior of the controller and can not be disabled
 * unfortuatelly.
 *
 * To work around the problem, we backup the current DABT handler address
 * and replace it with our own DABT handler, which only bounces right back
 * into the code.
 */
static void imx_pcie_fix_dabt_handler(bool set)
{
        extern uint32_t *_data_abort;
        uint32_t *data_abort_addr = (uint32_t *)&_data_abort;

        static const uint32_t data_abort_bounce_handler = 0xe25ef004;
        uint32_t data_abort_bounce_addr = (uint32_t)&data_abort_bounce_handler;

        static uint32_t data_abort_backup;

        if (set) {
                data_abort_backup = *data_abort_addr;
                *data_abort_addr = data_abort_bounce_addr;
        } else {
                *data_abort_addr = data_abort_backup;
        }
}

static int imx_pcie_read_cfg(struct imx_pcie_priv *priv, pci_dev_t d,
                             int where, u32 *val)
{
        void __iomem *va_address;
        int ret;

        ret = imx_pcie_addr_valid(d);
        if (ret) {
                *val = 0xffffffff;
                return 0;
        }

        va_address = get_bus_address(priv, d, where);

        /*
         * Read the PCIe config space. We must replace the DABT handler
         * here in case we got data abort from the PCIe controller, see
         * imx_pcie_fix_dabt_handler() description. Note that writing the
         * "val" with valid value is also imperative here as in case we
         * did got DABT, the val would contain random value.
         */
        imx_pcie_fix_dabt_handler(true);
        writel(0xffffffff, val);
        *val = readl(va_address);
        imx_pcie_fix_dabt_handler(false);

        return 0;
}

static int imx_pcie_write_cfg(struct imx_pcie_priv *priv, pci_dev_t d,
                              int where, u32 val)
{
        void __iomem *va_address = NULL;
        int ret;

        ret = imx_pcie_addr_valid(d);
        if (ret)
                return ret;

        va_address = get_bus_address(priv, d, where);

        /*
         * Write the PCIe config space. We must replace the DABT handler
         * here in case we got data abort from the PCIe controller, see
         * imx_pcie_fix_dabt_handler() description.
         */
        imx_pcie_fix_dabt_handler(true);
        writel(val, va_address);
        imx_pcie_fix_dabt_handler(false);

        return 0;
}

/*
 * Initial bus setup
 */
static int imx6_pcie_assert_core_reset(struct imx_pcie_priv *priv,
                                       bool prepare_for_boot)
{
        struct iomuxc *iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;

        if (is_mx6dqp())
                setbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_PCIE_SW_RST);

#if defined(CONFIG_MX6SX)
        struct gpc *gpc_regs = (struct gpc *)GPC_BASE_ADDR;

        /* SSP_EN is not used on MX6SX anymore */
        setbits_le32(&iomuxc_regs->gpr[12], IOMUXC_GPR12_TEST_POWERDOWN);
        /* Force PCIe PHY reset */
        setbits_le32(&iomuxc_regs->gpr[5], IOMUXC_GPR5_PCIE_BTNRST);
        /* Power up PCIe PHY */
        setbits_le32(&gpc_regs->cntr, PCIE_PHY_PUP_REQ);
#else
        /*
         * If the bootloader already enabled the link we need some special
         * handling to get the core back into a state where it is safe to
         * touch it for configuration.  As there is no dedicated reset signal
         * wired up for MX6QDL, we need to manually force LTSSM into "detect"
         * state before completely disabling LTSSM, which is a prerequisite
         * for core configuration.
         *
         * If both LTSSM_ENABLE and REF_SSP_ENABLE are active we have a strong
         * indication that the bootloader activated the link.
         */
        if (is_mx6dq() && prepare_for_boot) {
                u32 val, gpr1, gpr12;

                gpr1 = readl(&iomuxc_regs->gpr[1]);
                gpr12 = readl(&iomuxc_regs->gpr[12]);
                if ((gpr1 & IOMUXC_GPR1_PCIE_REF_CLK_EN) &&
                    (gpr12 & IOMUXC_GPR12_PCIE_CTL_2)) {
                        val = readl(priv->dbi_base + PCIE_PL_PFLR);
                        val &= ~PCIE_PL_PFLR_LINK_STATE_MASK;
                        val |= PCIE_PL_PFLR_FORCE_LINK;

                        imx_pcie_fix_dabt_handler(true);
                        writel(val, priv->dbi_base + PCIE_PL_PFLR);
                        imx_pcie_fix_dabt_handler(false);

                        gpr12 &= ~IOMUXC_GPR12_PCIE_CTL_2;
                        writel(val, &iomuxc_regs->gpr[12]);
                }
        }
        setbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_TEST_POWERDOWN);
        clrbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_REF_SSP_EN);
#endif

        return 0;
}

static int imx6_pcie_init_phy(void)
{
        struct iomuxc *iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;

        clrbits_le32(&iomuxc_regs->gpr[12], IOMUXC_GPR12_APPS_LTSSM_ENABLE);

        clrsetbits_le32(&iomuxc_regs->gpr[12],
                        IOMUXC_GPR12_DEVICE_TYPE_MASK,
                        IOMUXC_GPR12_DEVICE_TYPE_RC);
        clrsetbits_le32(&iomuxc_regs->gpr[12],
                        IOMUXC_GPR12_LOS_LEVEL_MASK,
                        IOMUXC_GPR12_LOS_LEVEL_9);

#ifdef CONFIG_MX6SX
        clrsetbits_le32(&iomuxc_regs->gpr[12],
                        IOMUXC_GPR12_RX_EQ_MASK,
                        IOMUXC_GPR12_RX_EQ_2);
#endif

        writel((0x0 << IOMUXC_GPR8_PCS_TX_DEEMPH_GEN1_OFFSET) |
               (0x0 << IOMUXC_GPR8_PCS_TX_DEEMPH_GEN2_3P5DB_OFFSET) |
               (20 << IOMUXC_GPR8_PCS_TX_DEEMPH_GEN2_6DB_OFFSET) |
               (127 << IOMUXC_GPR8_PCS_TX_SWING_FULL_OFFSET) |
               (127 << IOMUXC_GPR8_PCS_TX_SWING_LOW_OFFSET),
               &iomuxc_regs->gpr[8]);

        return 0;
}

__weak int imx6_pcie_toggle_power(void)
{
#ifdef CONFIG_PCIE_IMX_POWER_GPIO
        gpio_request(CONFIG_PCIE_IMX_POWER_GPIO, "pcie_power");
        gpio_direction_output(CONFIG_PCIE_IMX_POWER_GPIO, 0);
        mdelay(20);
        gpio_set_value(CONFIG_PCIE_IMX_POWER_GPIO, 1);
        mdelay(20);
        gpio_free(CONFIG_PCIE_IMX_POWER_GPIO);
#endif
        return 0;
}

__weak int imx6_pcie_toggle_reset(void)
{
        /*
         * See 'PCI EXPRESS BASE SPECIFICATION, REV 3.0, SECTION 6.6.1'
         * for detailed understanding of the PCIe CR reset logic.
         *
         * The PCIe #PERST reset line _MUST_ be connected, otherwise your
         * design does not conform to the specification. You must wait at
         * least 20 ms after de-asserting the #PERST so the EP device can
         * do self-initialisation.
         *
         * In case your #PERST pin is connected to a plain GPIO pin of the
         * CPU, you can define CONFIG_PCIE_IMX_PERST_GPIO in your board's
         * configuration file and the condition below will handle the rest
         * of the reset toggling.
         *
         * In case your #PERST toggling logic is more complex, for example
         * connected via CPLD or somesuch, you can override this function
         * in your board file and implement reset logic as needed. You must
         * not forget to wait at least 20 ms after de-asserting #PERST in
         * this case either though.
         *
         * In case your #PERST line of the PCIe EP device is not connected
         * at all, your design is broken and you should fix your design,
         * otherwise you will observe problems like for example the link
         * not coming up after rebooting the system back from running Linux
         * that uses the PCIe as well OR the PCIe link might not come up in
         * Linux at all in the first place since it's in some non-reset
         * state due to being previously used in U-Boot.
         */
#ifdef CONFIG_PCIE_IMX_PERST_GPIO
        gpio_request(CONFIG_PCIE_IMX_PERST_GPIO, "pcie_reset");
        gpio_direction_output(CONFIG_PCIE_IMX_PERST_GPIO, 0);
        mdelay(20);
        gpio_set_value(CONFIG_PCIE_IMX_PERST_GPIO, 1);
        mdelay(20);
        gpio_free(CONFIG_PCIE_IMX_PERST_GPIO);
#else
        puts("WARNING: Make sure the PCIe #PERST line is connected!\n");
#endif
        return 0;
}

static int imx6_pcie_deassert_core_reset(void)
{
        struct iomuxc *iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;

        imx6_pcie_toggle_power();

        enable_pcie_clock();

        if (is_mx6dqp())
                clrbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_PCIE_SW_RST);

        /*
         * Wait for the clock to settle a bit, when the clock are sourced
         * from the CPU, we need about 30 ms to settle.
         */
        mdelay(50);

#if defined(CONFIG_MX6SX)
        /* SSP_EN is not used on MX6SX anymore */
        clrbits_le32(&iomuxc_regs->gpr[12], IOMUXC_GPR12_TEST_POWERDOWN);
        /* Clear PCIe PHY reset bit */
        clrbits_le32(&iomuxc_regs->gpr[5], IOMUXC_GPR5_PCIE_BTNRST);
#else
        /* Enable PCIe */
        clrbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_TEST_POWERDOWN);
        setbits_le32(&iomuxc_regs->gpr[1], IOMUXC_GPR1_REF_SSP_EN);
#endif

        imx6_pcie_toggle_reset();

        return 0;
}

static int imx_pcie_link_up(struct imx_pcie_priv *priv)
{
        struct iomuxc *iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;
        uint32_t tmp;
        int count = 0;

        imx6_pcie_assert_core_reset(priv, false);
        imx6_pcie_init_phy();
        imx6_pcie_deassert_core_reset();

        imx_pcie_regions_setup(priv);

        /*
         * By default, the subordinate is set equally to the secondary
         * bus (0x01) when the RC boots.
         * This means that theoretically, only bus 1 is reachable from the RC.
         * Force the PCIe RC subordinate to 0xff, otherwise no downstream
         * devices will be detected if the enumeration is applied strictly.
         */
        tmp = readl(priv->dbi_base + 0x18);
        tmp |= (0xff << 16);
        writel(tmp, priv->dbi_base + 0x18);

        /*
         * FIXME: Force the PCIe RC to Gen1 operation
         * The RC must be forced into Gen1 mode before bringing the link
         * up, otherwise no downstream devices are detected. After the
         * link is up, a managed Gen1->Gen2 transition can be initiated.
         */
        tmp = readl(priv->dbi_base + 0x7c);
        tmp &= ~0xf;
        tmp |= 0x1;
        writel(tmp, priv->dbi_base + 0x7c);

        /* LTSSM enable, starting link. */
        setbits_le32(&iomuxc_regs->gpr[12], IOMUXC_GPR12_APPS_LTSSM_ENABLE);

        while (!imx6_pcie_link_up(priv)) {
                udelay(10);
                count++;
                if (count >= 4000) {
#ifdef CONFIG_PCI_SCAN_SHOW
                        puts("PCI:   pcie phy link never came up\n");
#endif
                        debug("DEBUG_R0: 0x%08x, DEBUG_R1: 0x%08x\n",
                              readl(priv->dbi_base + PCIE_PHY_DEBUG_R0),
                              readl(priv->dbi_base + PCIE_PHY_DEBUG_R1));
                        return -EINVAL;
                }
        }

        return 0;
}

#if !CONFIG_IS_ENABLED(DM_PCI)
static struct imx_pcie_priv imx_pcie_priv = {
        .dbi_base       = (void __iomem *)MX6_DBI_ADDR,
        .cfg_base       = (void __iomem *)MX6_ROOT_ADDR,
};

static struct imx_pcie_priv *priv = &imx_pcie_priv;

static int imx_pcie_read_config(struct pci_controller *hose, pci_dev_t d,
                                int where, u32 *val)
{
        struct imx_pcie_priv *priv = hose->priv_data;

        return imx_pcie_read_cfg(priv, d, where, val);
}

static int imx_pcie_write_config(struct pci_controller *hose, pci_dev_t d,
                                 int where, u32 val)
{
        struct imx_pcie_priv *priv = hose->priv_data;

        return imx_pcie_write_cfg(priv, d, where, val);
}

void imx_pcie_init(void)
{
        /* Static instance of the controller. */
        static struct pci_controller    pcc;
        struct pci_controller           *hose = &pcc;
        int ret;

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

        hose->priv_data = priv;

        /* PCI I/O space */
        pci_set_region(&hose->regions[0],
                       MX6_IO_ADDR, MX6_IO_ADDR,
                       MX6_IO_SIZE, PCI_REGION_IO);

        /* PCI memory space */
        pci_set_region(&hose->regions[1],
                       MX6_MEM_ADDR, MX6_MEM_ADDR,
                       MX6_MEM_SIZE, PCI_REGION_MEM);

        /* System memory space */
        pci_set_region(&hose->regions[2],
                       MMDC0_ARB_BASE_ADDR, MMDC0_ARB_BASE_ADDR,
                       0xefffffff, PCI_REGION_MEM | PCI_REGION_SYS_MEMORY);

        hose->region_count = 3;

        pci_set_ops(hose,
                    pci_hose_read_config_byte_via_dword,
                    pci_hose_read_config_word_via_dword,
                    imx_pcie_read_config,
                    pci_hose_write_config_byte_via_dword,
                    pci_hose_write_config_word_via_dword,
                    imx_pcie_write_config);

        /* Start the controller. */
        ret = imx_pcie_link_up(priv);

        if (!ret) {
                pci_register_hose(hose);
                hose->last_busno = pci_hose_scan(hose);
        }
}

void imx_pcie_remove(void)
{
        imx6_pcie_assert_core_reset(priv, true);
}

/* Probe function. */
void pci_init_board(void)
{
        imx_pcie_init();
}
#else
static int imx_pcie_dm_read_config(struct udevice *dev, pci_dev_t bdf,
                                   uint offset, ulong *value,
                                   enum pci_size_t size)
{
        struct imx_pcie_priv *priv = dev_get_priv(dev);
        u32 tmpval;
        int ret;

        ret = imx_pcie_read_cfg(priv, bdf, offset, &tmpval);
        if (ret)
                return ret;

        *value = pci_conv_32_to_size(tmpval, offset, size);
        return 0;
}

static int imx_pcie_dm_write_config(struct udevice *dev, pci_dev_t bdf,
                                    uint offset, ulong value,
                                    enum pci_size_t size)
{
        struct imx_pcie_priv *priv = dev_get_priv(dev);
        u32 tmpval, newval;
        int ret;

        ret = imx_pcie_read_cfg(priv, bdf, offset, &tmpval);
        if (ret)
                return ret;

        newval = pci_conv_size_to_32(tmpval, value, offset, size);
        return imx_pcie_write_cfg(priv, bdf, offset, newval);
}

static int imx_pcie_dm_probe(struct udevice *dev)
{
        struct imx_pcie_priv *priv = dev_get_priv(dev);

        return imx_pcie_link_up(priv);
}

static int imx_pcie_dm_remove(struct udevice *dev)
{
        struct imx_pcie_priv *priv = dev_get_priv(dev);

        imx6_pcie_assert_core_reset(priv, true);

        return 0;
}

static int imx_pcie_ofdata_to_platdata(struct udevice *dev)
{
        struct imx_pcie_priv *priv = dev_get_priv(dev);

        priv->dbi_base = (void __iomem *)devfdt_get_addr_index(dev, 0);
        priv->cfg_base = (void __iomem *)devfdt_get_addr_index(dev, 1);
        if (!priv->dbi_base || !priv->cfg_base)
                return -EINVAL;

        return 0;
}

static const struct dm_pci_ops imx_pcie_ops = {
        .read_config    = imx_pcie_dm_read_config,
        .write_config   = imx_pcie_dm_write_config,
};

static const struct udevice_id imx_pcie_ids[] = {
        { .compatible = "fsl,imx6q-pcie" },
        { }
};

U_BOOT_DRIVER(imx_pcie) = {
        .name                   = "imx_pcie",
        .id                     = UCLASS_PCI,
        .of_match               = imx_pcie_ids,
        .ops                    = &imx_pcie_ops,
        .probe                  = imx_pcie_dm_probe,
        .remove                 = imx_pcie_dm_remove,
        .ofdata_to_platdata     = imx_pcie_ofdata_to_platdata,
        .priv_auto_alloc_size   = sizeof(struct imx_pcie_priv),
        .flags                  = DM_FLAG_OS_PREPARE,
};
#endif