mmc: host: sh_mobile_sdhi: move card_busy from tmio to sdhi

[linux/fpc-iii.git] / drivers / pci / host / pci-imx6.c

/*
 * PCIe host controller driver for Freescale i.MX6 SoCs
 *
 * Copyright (C) 2013 Kosagi
 *              http://www.kosagi.com
 *
 * Author: Sean Cross <xobs@kosagi.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
#include <linux/module.h>
#include <linux/of_gpio.h>
#include <linux/of_device.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/resource.h>
#include <linux/signal.h>
#include <linux/types.h>
#include <linux/interrupt.h>

#include "pcie-designware.h"

#define to_imx6_pcie(x) container_of(x, struct imx6_pcie, pp)

enum imx6_pcie_variants {
        IMX6Q,
        IMX6SX,
        IMX6QP,
};

struct imx6_pcie {
        int                     reset_gpio;
        bool                    gpio_active_high;
        struct clk              *pcie_bus;
        struct clk              *pcie_phy;
        struct clk              *pcie_inbound_axi;
        struct clk              *pcie;
        struct pcie_port        pp;
        struct regmap           *iomuxc_gpr;
        enum imx6_pcie_variants variant;
        void __iomem            *mem_base;
        u32                     tx_deemph_gen1;
        u32                     tx_deemph_gen2_3p5db;
        u32                     tx_deemph_gen2_6db;
        u32                     tx_swing_full;
        u32                     tx_swing_low;
        int                     link_gen;
};

/* PCIe Root Complex registers (memory-mapped) */
#define PCIE_RC_LCR                             0x7c
#define PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1        0x1
#define PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2        0x2
#define PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK        0xf

#define PCIE_RC_LCSR                            0x80

/* 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_XMLH_LINK_IN_TRAINING (1 << 29)
#define PCIE_PHY_DEBUG_R1_XMLH_LINK_UP          (1 << 4)

#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_ACK_LOC 16

#define PCIE_LINK_WIDTH_SPEED_CONTROL   0x80C
#define PORT_LOGIC_SPEED_CHANGE         (0x1 << 17)

/* PHY registers (not memory-mapped) */
#define PCIE_PHY_RX_ASIC_OUT 0x100D
#define PCIE_PHY_RX_ASIC_OUT_VALID      (1 << 0)

#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)

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);

        return pcie_phy_poll_ack(dbi_base, 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);

        return pcie_phy_poll_ack(dbi_base, 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 void imx6_pcie_reset_phy(struct pcie_port *pp)
{
        u32 tmp;

        pcie_phy_read(pp->dbi_base, PHY_RX_OVRD_IN_LO, &tmp);
        tmp |= (PHY_RX_OVRD_IN_LO_RX_DATA_EN |
                PHY_RX_OVRD_IN_LO_RX_PLL_EN);
        pcie_phy_write(pp->dbi_base, PHY_RX_OVRD_IN_LO, tmp);

        usleep_range(2000, 3000);

        pcie_phy_read(pp->dbi_base, PHY_RX_OVRD_IN_LO, &tmp);
        tmp &= ~(PHY_RX_OVRD_IN_LO_RX_DATA_EN |
                  PHY_RX_OVRD_IN_LO_RX_PLL_EN);
        pcie_phy_write(pp->dbi_base, PHY_RX_OVRD_IN_LO, tmp);
}

/*  Added for PCI abort handling */
static int imx6q_pcie_abort_handler(unsigned long addr,
                unsigned int fsr, struct pt_regs *regs)
{
        return 0;
}

static int imx6_pcie_assert_core_reset(struct pcie_port *pp)
{
        struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
        u32 val, gpr1, gpr12;

        switch (imx6_pcie->variant) {
        case IMX6SX:
                regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
                                   IMX6SX_GPR12_PCIE_TEST_POWERDOWN,
                                   IMX6SX_GPR12_PCIE_TEST_POWERDOWN);
                /* Force PCIe PHY reset */
                regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR5,
                                   IMX6SX_GPR5_PCIE_BTNRST_RESET,
                                   IMX6SX_GPR5_PCIE_BTNRST_RESET);
                break;
        case IMX6QP:
                regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
                                   IMX6Q_GPR1_PCIE_SW_RST,
                                   IMX6Q_GPR1_PCIE_SW_RST);
                break;
        case IMX6Q:
                /*
                 * 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.
                 */
                regmap_read(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, &gpr1);
                regmap_read(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, &gpr12);

                if ((gpr1 & IMX6Q_GPR1_PCIE_REF_CLK_EN) &&
                    (gpr12 & IMX6Q_GPR12_PCIE_CTL_2)) {
                        val = readl(pp->dbi_base + PCIE_PL_PFLR);
                        val &= ~PCIE_PL_PFLR_LINK_STATE_MASK;
                        val |= PCIE_PL_PFLR_FORCE_LINK;
                        writel(val, pp->dbi_base + PCIE_PL_PFLR);

                        regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
                                           IMX6Q_GPR12_PCIE_CTL_2, 0 << 10);
                }

                regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
                                   IMX6Q_GPR1_PCIE_TEST_PD, 1 << 18);
                regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
                                   IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16);
                break;
        }

        return 0;
}

static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
{
        struct pcie_port *pp = &imx6_pcie->pp;
        int ret = 0;

        switch (imx6_pcie->variant) {
        case IMX6SX:
                ret = clk_prepare_enable(imx6_pcie->pcie_inbound_axi);
                if (ret) {
                        dev_err(pp->dev, "unable to enable pcie_axi clock\n");
                        break;
                }

                regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
                                   IMX6SX_GPR12_PCIE_TEST_POWERDOWN, 0);
                break;
        case IMX6QP:            /* FALLTHROUGH */
        case IMX6Q:
                /* power up core phy and enable ref clock */
                regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
                                   IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18);
                /*
                 * the async reset input need ref clock to sync internally,
                 * when the ref clock comes after reset, internal synced
                 * reset time is too short, cannot meet the requirement.
                 * add one ~10us delay here.
                 */
                udelay(10);
                regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
                                   IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16);
                break;
        }

        return ret;
}

static int imx6_pcie_deassert_core_reset(struct pcie_port *pp)
{
        struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
        int ret;

        ret = clk_prepare_enable(imx6_pcie->pcie_phy);
        if (ret) {
                dev_err(pp->dev, "unable to enable pcie_phy clock\n");
                goto err_pcie_phy;
        }

        ret = clk_prepare_enable(imx6_pcie->pcie_bus);
        if (ret) {
                dev_err(pp->dev, "unable to enable pcie_bus clock\n");
                goto err_pcie_bus;
        }

        ret = clk_prepare_enable(imx6_pcie->pcie);
        if (ret) {
                dev_err(pp->dev, "unable to enable pcie clock\n");
                goto err_pcie;
        }

        ret = imx6_pcie_enable_ref_clk(imx6_pcie);
        if (ret) {
                dev_err(pp->dev, "unable to enable pcie ref clock\n");
                goto err_ref_clk;
        }

        /* allow the clocks to stabilize */
        usleep_range(200, 500);

        /* Some boards don't have PCIe reset GPIO. */
        if (gpio_is_valid(imx6_pcie->reset_gpio)) {
                gpio_set_value_cansleep(imx6_pcie->reset_gpio,
                                        imx6_pcie->gpio_active_high);
                msleep(100);
                gpio_set_value_cansleep(imx6_pcie->reset_gpio,
                                        !imx6_pcie->gpio_active_high);
        }

        switch (imx6_pcie->variant) {
        case IMX6SX:
                regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR5,
                                   IMX6SX_GPR5_PCIE_BTNRST_RESET, 0);
                break;
        case IMX6QP:
                regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
                                   IMX6Q_GPR1_PCIE_SW_RST, 0);

                usleep_range(200, 500);
                break;
        case IMX6Q:             /* Nothing to do */
                break;
        }

        return 0;

err_ref_clk:
        clk_disable_unprepare(imx6_pcie->pcie);
err_pcie:
        clk_disable_unprepare(imx6_pcie->pcie_bus);
err_pcie_bus:
        clk_disable_unprepare(imx6_pcie->pcie_phy);
err_pcie_phy:
        return ret;
}

static void imx6_pcie_init_phy(struct pcie_port *pp)
{
        struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);

        if (imx6_pcie->variant == IMX6SX)
                regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
                                   IMX6SX_GPR12_PCIE_RX_EQ_MASK,
                                   IMX6SX_GPR12_PCIE_RX_EQ_2);

        regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
                        IMX6Q_GPR12_PCIE_CTL_2, 0 << 10);

        /* configure constant input signal to the pcie ctrl and phy */
        regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
                        IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT << 12);
        regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
                        IMX6Q_GPR12_LOS_LEVEL, 9 << 4);

        regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
                           IMX6Q_GPR8_TX_DEEMPH_GEN1,
                           imx6_pcie->tx_deemph_gen1 << 0);
        regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
                           IMX6Q_GPR8_TX_DEEMPH_GEN2_3P5DB,
                           imx6_pcie->tx_deemph_gen2_3p5db << 6);
        regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
                           IMX6Q_GPR8_TX_DEEMPH_GEN2_6DB,
                           imx6_pcie->tx_deemph_gen2_6db << 12);
        regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
                           IMX6Q_GPR8_TX_SWING_FULL,
                           imx6_pcie->tx_swing_full << 18);
        regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
                           IMX6Q_GPR8_TX_SWING_LOW,
                           imx6_pcie->tx_swing_low << 25);
}

static int imx6_pcie_wait_for_link(struct pcie_port *pp)
{
        /* check if the link is up or not */
        if (!dw_pcie_wait_for_link(pp))
                return 0;

        dev_dbg(pp->dev, "DEBUG_R0: 0x%08x, DEBUG_R1: 0x%08x\n",
                readl(pp->dbi_base + PCIE_PHY_DEBUG_R0),
                readl(pp->dbi_base + PCIE_PHY_DEBUG_R1));
        return -ETIMEDOUT;
}

static int imx6_pcie_wait_for_speed_change(struct pcie_port *pp)
{
        u32 tmp;
        unsigned int retries;

        for (retries = 0; retries < 200; retries++) {
                tmp = readl(pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL);
                /* Test if the speed change finished. */
                if (!(tmp & PORT_LOGIC_SPEED_CHANGE))
                        return 0;
                usleep_range(100, 1000);
        }

        dev_err(pp->dev, "Speed change timeout\n");
        return -EINVAL;
}

static irqreturn_t imx6_pcie_msi_handler(int irq, void *arg)
{
        struct pcie_port *pp = arg;

        return dw_handle_msi_irq(pp);
}

static int imx6_pcie_establish_link(struct pcie_port *pp)
{
        struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
        u32 tmp;
        int ret;

        /*
         * Force Gen1 operation when starting the link.  In case the link is
         * started in Gen2 mode, there is a possibility the devices on the
         * bus will not be detected at all.  This happens with PCIe switches.
         */
        tmp = readl(pp->dbi_base + PCIE_RC_LCR);
        tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK;
        tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1;
        writel(tmp, pp->dbi_base + PCIE_RC_LCR);

        /* Start LTSSM. */
        regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
                        IMX6Q_GPR12_PCIE_CTL_2, 1 << 10);

        ret = imx6_pcie_wait_for_link(pp);
        if (ret) {
                dev_info(pp->dev, "Link never came up\n");
                goto err_reset_phy;
        }

        if (imx6_pcie->link_gen == 2) {
                /* Allow Gen2 mode after the link is up. */
                tmp = readl(pp->dbi_base + PCIE_RC_LCR);
                tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK;
                tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2;
                writel(tmp, pp->dbi_base + PCIE_RC_LCR);
        } else {
                dev_info(pp->dev, "Link: Gen2 disabled\n");
        }

        /*
         * Start Directed Speed Change so the best possible speed both link
         * partners support can be negotiated.
         */
        tmp = readl(pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL);
        tmp |= PORT_LOGIC_SPEED_CHANGE;
        writel(tmp, pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL);

        ret = imx6_pcie_wait_for_speed_change(pp);
        if (ret) {
                dev_err(pp->dev, "Failed to bring link up!\n");
                goto err_reset_phy;
        }

        /* Make sure link training is finished as well! */
        ret = imx6_pcie_wait_for_link(pp);
        if (ret) {
                dev_err(pp->dev, "Failed to bring link up!\n");
                goto err_reset_phy;
        }

        tmp = readl(pp->dbi_base + PCIE_RC_LCSR);
        dev_info(pp->dev, "Link up, Gen%i\n", (tmp >> 16) & 0xf);
        return 0;

err_reset_phy:
        dev_dbg(pp->dev, "PHY DEBUG_R0=0x%08x DEBUG_R1=0x%08x\n",
                readl(pp->dbi_base + PCIE_PHY_DEBUG_R0),
                readl(pp->dbi_base + PCIE_PHY_DEBUG_R1));
        imx6_pcie_reset_phy(pp);

        return ret;
}

static void imx6_pcie_host_init(struct pcie_port *pp)
{
        imx6_pcie_assert_core_reset(pp);

        imx6_pcie_init_phy(pp);

        imx6_pcie_deassert_core_reset(pp);

        dw_pcie_setup_rc(pp);

        imx6_pcie_establish_link(pp);

        if (IS_ENABLED(CONFIG_PCI_MSI))
                dw_pcie_msi_init(pp);
}

static int imx6_pcie_link_up(struct pcie_port *pp)
{
        return readl(pp->dbi_base + PCIE_PHY_DEBUG_R1) &
                        PCIE_PHY_DEBUG_R1_XMLH_LINK_UP;
}

static struct pcie_host_ops imx6_pcie_host_ops = {
        .link_up = imx6_pcie_link_up,
        .host_init = imx6_pcie_host_init,
};

static int __init imx6_add_pcie_port(struct pcie_port *pp,
                        struct platform_device *pdev)
{
        int ret;

        if (IS_ENABLED(CONFIG_PCI_MSI)) {
                pp->msi_irq = platform_get_irq_byname(pdev, "msi");
                if (pp->msi_irq <= 0) {
                        dev_err(&pdev->dev, "failed to get MSI irq\n");
                        return -ENODEV;
                }

                ret = devm_request_irq(&pdev->dev, pp->msi_irq,
                                       imx6_pcie_msi_handler,
                                       IRQF_SHARED | IRQF_NO_THREAD,
                                       "mx6-pcie-msi", pp);
                if (ret) {
                        dev_err(&pdev->dev, "failed to request MSI irq\n");
                        return ret;
                }
        }

        pp->root_bus_nr = -1;
        pp->ops = &imx6_pcie_host_ops;

        ret = dw_pcie_host_init(pp);
        if (ret) {
                dev_err(&pdev->dev, "failed to initialize host\n");
                return ret;
        }

        return 0;
}

static int __init imx6_pcie_probe(struct platform_device *pdev)
{
        struct imx6_pcie *imx6_pcie;
        struct pcie_port *pp;
        struct device_node *np = pdev->dev.of_node;
        struct resource *dbi_base;
        struct device_node *node = pdev->dev.of_node;
        int ret;

        imx6_pcie = devm_kzalloc(&pdev->dev, sizeof(*imx6_pcie), GFP_KERNEL);
        if (!imx6_pcie)
                return -ENOMEM;

        pp = &imx6_pcie->pp;
        pp->dev = &pdev->dev;

        imx6_pcie->variant =
                (enum imx6_pcie_variants)of_device_get_match_data(&pdev->dev);

        /* Added for PCI abort handling */
        hook_fault_code(16 + 6, imx6q_pcie_abort_handler, SIGBUS, 0,
                "imprecise external abort");

        dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        pp->dbi_base = devm_ioremap_resource(&pdev->dev, dbi_base);
        if (IS_ERR(pp->dbi_base))
                return PTR_ERR(pp->dbi_base);

        /* Fetch GPIOs */
        imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0);
        imx6_pcie->gpio_active_high = of_property_read_bool(np,
                                                "reset-gpio-active-high");
        if (gpio_is_valid(imx6_pcie->reset_gpio)) {
                ret = devm_gpio_request_one(&pdev->dev, imx6_pcie->reset_gpio,
                                imx6_pcie->gpio_active_high ?
                                        GPIOF_OUT_INIT_HIGH :
                                        GPIOF_OUT_INIT_LOW,
                                "PCIe reset");
                if (ret) {
                        dev_err(&pdev->dev, "unable to get reset gpio\n");
                        return ret;
                }
        }

        /* Fetch clocks */
        imx6_pcie->pcie_phy = devm_clk_get(&pdev->dev, "pcie_phy");
        if (IS_ERR(imx6_pcie->pcie_phy)) {
                dev_err(&pdev->dev,
                        "pcie_phy clock source missing or invalid\n");
                return PTR_ERR(imx6_pcie->pcie_phy);
        }

        imx6_pcie->pcie_bus = devm_clk_get(&pdev->dev, "pcie_bus");
        if (IS_ERR(imx6_pcie->pcie_bus)) {
                dev_err(&pdev->dev,
                        "pcie_bus clock source missing or invalid\n");
                return PTR_ERR(imx6_pcie->pcie_bus);
        }

        imx6_pcie->pcie = devm_clk_get(&pdev->dev, "pcie");
        if (IS_ERR(imx6_pcie->pcie)) {
                dev_err(&pdev->dev,
                        "pcie clock source missing or invalid\n");
                return PTR_ERR(imx6_pcie->pcie);
        }

        if (imx6_pcie->variant == IMX6SX) {
                imx6_pcie->pcie_inbound_axi = devm_clk_get(&pdev->dev,
                                                           "pcie_inbound_axi");
                if (IS_ERR(imx6_pcie->pcie_inbound_axi)) {
                        dev_err(&pdev->dev,
                                "pcie_incbound_axi clock missing or invalid\n");
                        return PTR_ERR(imx6_pcie->pcie_inbound_axi);
                }
        }

        /* Grab GPR config register range */
        imx6_pcie->iomuxc_gpr =
                 syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");
        if (IS_ERR(imx6_pcie->iomuxc_gpr)) {
                dev_err(&pdev->dev, "unable to find iomuxc registers\n");
                return PTR_ERR(imx6_pcie->iomuxc_gpr);
        }

        /* Grab PCIe PHY Tx Settings */
        if (of_property_read_u32(node, "fsl,tx-deemph-gen1",
                                 &imx6_pcie->tx_deemph_gen1))
                imx6_pcie->tx_deemph_gen1 = 0;

        if (of_property_read_u32(node, "fsl,tx-deemph-gen2-3p5db",
                                 &imx6_pcie->tx_deemph_gen2_3p5db))
                imx6_pcie->tx_deemph_gen2_3p5db = 0;

        if (of_property_read_u32(node, "fsl,tx-deemph-gen2-6db",
                                 &imx6_pcie->tx_deemph_gen2_6db))
                imx6_pcie->tx_deemph_gen2_6db = 20;

        if (of_property_read_u32(node, "fsl,tx-swing-full",
                                 &imx6_pcie->tx_swing_full))
                imx6_pcie->tx_swing_full = 127;

        if (of_property_read_u32(node, "fsl,tx-swing-low",
                                 &imx6_pcie->tx_swing_low))
                imx6_pcie->tx_swing_low = 127;

        /* Limit link speed */
        ret = of_property_read_u32(pp->dev->of_node, "fsl,max-link-speed",
                                   &imx6_pcie->link_gen);
        if (ret)
                imx6_pcie->link_gen = 1;

        ret = imx6_add_pcie_port(pp, pdev);
        if (ret < 0)
                return ret;

        platform_set_drvdata(pdev, imx6_pcie);
        return 0;
}

static void imx6_pcie_shutdown(struct platform_device *pdev)
{
        struct imx6_pcie *imx6_pcie = platform_get_drvdata(pdev);

        /* bring down link, so bootloader gets clean state in case of reboot */
        imx6_pcie_assert_core_reset(&imx6_pcie->pp);
}

static const struct of_device_id imx6_pcie_of_match[] = {
        { .compatible = "fsl,imx6q-pcie",  .data = (void *)IMX6Q,  },
        { .compatible = "fsl,imx6sx-pcie", .data = (void *)IMX6SX, },
        { .compatible = "fsl,imx6qp-pcie", .data = (void *)IMX6QP, },
        {},
};
MODULE_DEVICE_TABLE(of, imx6_pcie_of_match);

static struct platform_driver imx6_pcie_driver = {
        .driver = {
                .name   = "imx6q-pcie",
                .of_match_table = imx6_pcie_of_match,
        },
        .shutdown = imx6_pcie_shutdown,
};

/* Freescale PCIe driver does not allow module unload */

static int __init imx6_pcie_init(void)
{
        return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe);
}
module_init(imx6_pcie_init);

MODULE_AUTHOR("Sean Cross <xobs@kosagi.com>");
MODULE_DESCRIPTION("Freescale i.MX6 PCIe host controller driver");
MODULE_LICENSE("GPL v2");