path: root/drivers/pci/pci-imx6.c

// SPDX-License-Identifier: GPL-2.0
/*
 * PCIe host controller driver for Freescale i.MX6 SoCs
 *
 * Copyright (C) 2013 Kosagi
 *		http://www.kosagi.com
 *
 * Author: Sean Cross <xobs@kosagi.com>
 */

#include <common.h>
#include <clock.h>
#include <abort.h>
#include <malloc.h>
#include <io.h>
#include <init.h>
#include <gpio.h>
#include <asm/mmu.h>
#include <of_gpio.h>
#include <of_device.h>
#include <linux/clk.h>
#include <linux/kernel.h>
#include <of_address.h>
#include <of_pci.h>
#include <linux/pci.h>
#include <linux/phy/phy.h>
#include <linux/reset.h>
#include <linux/sizes.h>
#include <linux/bitfield.h>
#include <mfd/imx6q-iomuxc-gpr.h>
#include <mfd/imx7-iomuxc-gpr.h>

#include <mach/imx6-regs.h>
#include <mach/imx7-regs.h>
#include <mach/imx8mq-regs.h>

#include "pcie-designware.h"

#define IMX8MQ_GPR_PCIE_REF_USE_PAD            BIT(9)
#define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN    BIT(10)
#define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE       BIT(11)
#define IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE    GENMASK(11, 8)
#define IMX8MQ_PCIE2_BASE_ADDR			0x33c00000

#define to_imx6_pcie(x)	((x)->dev->priv)

enum imx6_pcie_variants {
	IMX6Q,
	IMX6QP,
	IMX7D,
	IMX8MQ,
};

#define IMX6_PCIE_FLAG_IMX6_PHY			BIT(0)
#define IMX6_PCIE_FLAG_IMX6_SPEED_CHANGE	BIT(1)

struct imx6_pcie_drvdata {
	enum imx6_pcie_variants variant;
	u32 flags;
};

struct imx6_pcie {
	struct dw_pcie		*pci;
	int			reset_gpio;
	struct clk		*pcie_bus;
	struct clk		*pcie_phy;
	struct clk		*pcie;
	struct clk              *pcie_aux;
	void __iomem		*iomuxc_gpr;
	u32			controller_id;
	struct reset_control	*pciephy_reset;
	struct reset_control	*apps_reset;
	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;
	const struct imx6_pcie_drvdata *drvdata;
};

/* Parameters for the waiting for PCIe PHY PLL to lock on i.MX7 */
#define PHY_PLL_LOCK_WAIT_MAX_RETRIES  2000
#define PHY_PLL_LOCK_WAIT_USLEEP_MIN   50
#define PHY_PLL_LOCK_WAIT_USLEEP_MAX   200

/* 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_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 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(struct imx6_pcie *imx6_pcie, int exp_val)
{
	struct dw_pcie *pci = imx6_pcie->pci;
	u32 val;
	u32 max_iterations = 10;
	u32 wait_counter = 0;

	do {
		val = dw_pcie_readl_dbi(pci, 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(struct imx6_pcie *imx6_pcie, int addr)
{
	struct dw_pcie *pci = imx6_pcie->pci;
	u32 val;
	int ret;

	val = addr << PCIE_PHY_CTRL_DATA_LOC;

	val |= (0x1 << PCIE_PHY_CTRL_CAP_ADR_LOC);
	dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, val);

	ret = pcie_phy_poll_ack(imx6_pcie, 1);
	if (ret)
		return ret;

	val = addr << PCIE_PHY_CTRL_DATA_LOC;
	dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, val);

	return pcie_phy_poll_ack(imx6_pcie, 0);
}

/* Read from the 16-bit PCIe PHY control registers (not memory-mapped) */
static int pcie_phy_read(struct imx6_pcie *imx6_pcie, int addr , int *data)
{
	struct dw_pcie *pci = imx6_pcie->pci;
	u32 val, phy_ctl;
	int ret;

	ret = pcie_phy_wait_ack(imx6_pcie, addr);
	if (ret)
		return ret;

	/* assert Read signal */
	phy_ctl = 0x1 << PCIE_PHY_CTRL_RD_LOC;
	dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, phy_ctl);

	ret = pcie_phy_poll_ack(imx6_pcie, 1);
	if (ret)
		return ret;

	val = dw_pcie_readl_dbi(pci, PCIE_PHY_STAT);
	*data = val & 0xffff;

	/* deassert Read signal */
	dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, 0x00);

	return pcie_phy_poll_ack(imx6_pcie, 0);
}

static int pcie_phy_write(struct imx6_pcie *imx6_pcie, int addr, int data)
{
	struct dw_pcie *pci = imx6_pcie->pci;
	u32 var;
	int ret;

	/* write addr */
	/* cap addr */
	ret = pcie_phy_wait_ack(imx6_pcie, addr);
	if (ret)
		return ret;

	var = data << PCIE_PHY_CTRL_DATA_LOC;
	dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, var);

	/* capture data */
	var |= (0x1 << PCIE_PHY_CTRL_CAP_DAT_LOC);
	dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, var);

	ret = pcie_phy_poll_ack(imx6_pcie, 1);
	if (ret)
		return ret;

	/* deassert cap data */
	var = data << PCIE_PHY_CTRL_DATA_LOC;
	dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, var);

	/* wait for ack de-assertion */
	ret = pcie_phy_poll_ack(imx6_pcie, 0);
	if (ret)
		return ret;

	/* assert wr signal */
	var = 0x1 << PCIE_PHY_CTRL_WR_LOC;
	dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, var);

	/* wait for ack */
	ret = pcie_phy_poll_ack(imx6_pcie, 1);
	if (ret)
		return ret;

	/* deassert wr signal */
	var = data << PCIE_PHY_CTRL_DATA_LOC;
	dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, var);

	/* wait for ack de-assertion */
	ret = pcie_phy_poll_ack(imx6_pcie, 0);
	if (ret)
		return ret;

	dw_pcie_writel_dbi(pci, PCIE_PHY_CTRL, 0x0);

	return 0;
}

static void imx6_pcie_reset_phy(struct imx6_pcie *imx6_pcie)
{
	uint32_t temp;

	if (!(imx6_pcie->drvdata->flags & IMX6_PCIE_FLAG_IMX6_PHY))
		return;

	pcie_phy_read(imx6_pcie, 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(imx6_pcie, PHY_RX_OVRD_IN_LO, temp);

	udelay(2000);

	pcie_phy_read(imx6_pcie, 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(imx6_pcie, PHY_RX_OVRD_IN_LO, temp);
}

static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
{
	u32 gpr1;

	switch (imx6_pcie->drvdata->variant) {
	case IMX7D:
	case IMX8MQ:
		reset_control_assert(imx6_pcie->pciephy_reset);
		reset_control_assert(imx6_pcie->apps_reset);
		break;
	case IMX6QP:
		gpr1 = readl(imx6_pcie->iomuxc_gpr + IOMUXC_GPR1);
		gpr1 |= IMX6Q_GPR1_PCIE_SW_RST;
		writel(gpr1, imx6_pcie->iomuxc_gpr + IOMUXC_GPR1);
		break;
	case IMX6Q:
		gpr1 = readl(imx6_pcie->iomuxc_gpr + IOMUXC_GPR1);
		gpr1 |= IMX6Q_GPR1_PCIE_TEST_PD;
		writel(gpr1, imx6_pcie->iomuxc_gpr + IOMUXC_GPR1);

		gpr1 &= ~IMX6Q_GPR1_PCIE_REF_CLK_EN;
		writel(gpr1, imx6_pcie->iomuxc_gpr + IOMUXC_GPR1);
		break;
	}
}

static unsigned int imx6_pcie_grp_offset(const struct imx6_pcie *imx6_pcie)
{
	WARN_ON(imx6_pcie->drvdata->variant != IMX8MQ);
	return imx6_pcie->controller_id == 1 ? IOMUXC_GPR16 : IOMUXC_GPR14;
}

static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
{
	struct device_d *dev = imx6_pcie->pci->dev;
	u32 gpr1, gpr1x;
	unsigned int offset;
	int ret;

	switch (imx6_pcie->drvdata->variant) {
	case IMX6QP:
	case IMX6Q:		/* FALLTHROUGH */
		/* power up core phy and enable ref clock */
		gpr1 = readl(imx6_pcie->iomuxc_gpr + IOMUXC_GPR1);
		gpr1 &= ~IMX6Q_GPR1_PCIE_TEST_PD;
		writel(gpr1, imx6_pcie->iomuxc_gpr + IOMUXC_GPR1);
		/*
		 * 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);
		gpr1 = readl(imx6_pcie->iomuxc_gpr + IOMUXC_GPR1);
		gpr1 |= IMX6Q_GPR1_PCIE_REF_CLK_EN;
		writel(gpr1, imx6_pcie->iomuxc_gpr + IOMUXC_GPR1);
		break;
	case IMX7D:
		break;
	case IMX8MQ:
		ret = clk_enable(imx6_pcie->pcie_aux);
		if (ret) {
			dev_err(dev, "unable to enable pcie_aux clock\n");
			return ret;
		}

		offset = imx6_pcie_grp_offset(imx6_pcie);
		/*
		 * Set the over ride low and enabled
		 * make sure that REF_CLK is turned on.
		 */
		gpr1x = readl(imx6_pcie->iomuxc_gpr + offset);
		gpr1x &= ~IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE;
		writel(gpr1x, imx6_pcie->iomuxc_gpr + offset);

		gpr1x = readl(imx6_pcie->iomuxc_gpr + offset);
		gpr1x |= IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN;
		writel(gpr1x, imx6_pcie->iomuxc_gpr + offset);
		break;
	}

	return 0;
}

static void imx7d_pcie_wait_for_phy_pll_lock(struct imx6_pcie *imx6_pcie)
{
	u32 val;
	unsigned int retries;
	struct device_d *dev = imx6_pcie->pci->dev;

	for (retries = 0; retries < PHY_PLL_LOCK_WAIT_MAX_RETRIES; retries++) {
		val = readl(imx6_pcie->iomuxc_gpr + IOMUXC_GPR22);

		if (val & IMX7D_GPR22_PCIE_PHY_PLL_LOCKED)
			return;

		udelay(PHY_PLL_LOCK_WAIT_USLEEP_MAX);
	}

	dev_err(dev, "PCIe PLL lock timeout\n");
}

static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
{
	struct device_d *dev = imx6_pcie->pci->dev;
	int ret;
	u32 gpr1;

	ret = clk_enable(imx6_pcie->pcie_phy);
	if (ret) {
		dev_err(dev, "unable to enable pcie_phy clock\n");
		return;
	}

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

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

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

	/* allow the clocks to stabilize */
	udelay(200);

	/* Some boards don't have PCIe reset GPIO. */
	if (gpio_is_valid(imx6_pcie->reset_gpio)) {
		gpio_set_value(imx6_pcie->reset_gpio, 0);
		mdelay(100);
		gpio_set_value(imx6_pcie->reset_gpio, 1);
	}

	/*
	 * Release the PCIe PHY reset here
	 */
	switch (imx6_pcie->drvdata->variant) {
	case IMX8MQ:
		reset_control_deassert(imx6_pcie->pciephy_reset);
		break;
	case IMX7D:
		reset_control_deassert(imx6_pcie->pciephy_reset);
		imx7d_pcie_wait_for_phy_pll_lock(imx6_pcie);
		break;
	case IMX6QP:
		gpr1 = readl(imx6_pcie->iomuxc_gpr + IOMUXC_GPR1);
		gpr1 &= ~IMX6Q_GPR1_PCIE_SW_RST;
		writel(gpr1, imx6_pcie->iomuxc_gpr + IOMUXC_GPR1);

		udelay(200);
		break;
	case IMX6Q:		/* Nothing to do */
		break;
	}

	return;

err_ref_clk:
	clk_disable(imx6_pcie->pcie);
err_pcie:
	clk_disable(imx6_pcie->pcie_bus);
err_pcie_bus:
	clk_disable(imx6_pcie->pcie_phy);
}

static void imx6_pcie_configure_type(struct imx6_pcie *imx6_pcie)
{
	unsigned int mask, val;
	u32 gpr12;

	if (imx6_pcie->drvdata->variant == IMX8MQ &&
	    imx6_pcie->controller_id == 1) {
		mask   = IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE;
		val    = FIELD_PREP(IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE,
				    PCI_EXP_TYPE_ROOT_PORT);
	} else {
		mask = IMX6Q_GPR12_DEVICE_TYPE;
		val  = FIELD_PREP(IMX6Q_GPR12_DEVICE_TYPE,
				  PCI_EXP_TYPE_ROOT_PORT);
	}

	gpr12  = readl(imx6_pcie->iomuxc_gpr + IOMUXC_GPR12);
	gpr12 &= ~mask;
	gpr12 |= val;
	writel(gpr12, imx6_pcie->iomuxc_gpr + IOMUXC_GPR12);
}

static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
{
	u32 gpr12, gpr8, gpr1x;
	unsigned int offset;

	switch (imx6_pcie->drvdata->variant) {
	case IMX8MQ:
		offset = imx6_pcie_grp_offset(imx6_pcie);
		/*
		 * TODO: Currently this code assumes external
		 * oscillator is being used
		 */
		gpr1x = readl(imx6_pcie->iomuxc_gpr + offset);
		gpr1x |= IMX8MQ_GPR_PCIE_REF_USE_PAD;
		writel(gpr1x, imx6_pcie->iomuxc_gpr + offset);
		break;
	case IMX7D:
		gpr12 = readl(imx6_pcie->iomuxc_gpr + IOMUXC_GPR12);
		gpr12 &= ~IMX7D_GPR12_PCIE_PHY_REFCLK_SEL;
		writel(gpr12, imx6_pcie->iomuxc_gpr + IOMUXC_GPR12);
		break;
	case IMX6QP:
	case IMX6Q:	/* FALLTHROUGH */
		gpr12 = readl(imx6_pcie->iomuxc_gpr + IOMUXC_GPR12);
		gpr12 &= ~IMX6Q_GPR12_PCIE_CTL_2;
		writel(gpr12, imx6_pcie->iomuxc_gpr + IOMUXC_GPR12);

		/* configure constant input signal to the pcie ctrl and phy */
		gpr12 &= ~IMX6Q_GPR12_LOS_LEVEL;
		gpr12 |= 9 << 4;
		writel(gpr12, imx6_pcie->iomuxc_gpr + IOMUXC_GPR12);

		gpr8 = readl(imx6_pcie->iomuxc_gpr + IOMUXC_GPR8);
		gpr8 &= ~IMX6Q_GPR8_TX_DEEMPH_GEN1;
		gpr8 |= imx6_pcie->tx_deemph_gen1 << 0;
		writel(gpr8, imx6_pcie->iomuxc_gpr + IOMUXC_GPR8);

		gpr8 &= ~IMX6Q_GPR8_TX_DEEMPH_GEN2_3P5DB;
		gpr8 |= imx6_pcie->tx_deemph_gen2_3p5db << 6;
		writel(gpr8, imx6_pcie->iomuxc_gpr + IOMUXC_GPR8);

		gpr8 &= ~IMX6Q_GPR8_TX_DEEMPH_GEN2_6DB;
		gpr8 |= imx6_pcie->tx_deemph_gen2_6db << 12;
		writel(gpr8, imx6_pcie->iomuxc_gpr + IOMUXC_GPR8);

		gpr8 &= ~IMX6Q_GPR8_TX_SWING_FULL;
		gpr8 |= imx6_pcie->tx_swing_full << 18;
		writel(gpr8, imx6_pcie->iomuxc_gpr + IOMUXC_GPR8);

		gpr8 &= ~IMX6Q_GPR8_TX_SWING_LOW;
		gpr8 |= imx6_pcie->tx_swing_low << 25;
		writel(gpr8, imx6_pcie->iomuxc_gpr + IOMUXC_GPR8);
		break;
	}

	imx6_pcie_configure_type(imx6_pcie);
}

static int imx6_pcie_wait_for_link(struct imx6_pcie *imx6_pcie)
{
	return dw_pcie_wait_for_link(imx6_pcie->pci);
}

static int imx6_pcie_wait_for_speed_change(struct imx6_pcie *imx6_pcie)
{
	struct dw_pcie *pci = imx6_pcie->pci;
	struct device_d *dev = pci->dev;
	uint32_t tmp;
	uint64_t start = get_time_ns();

	while (!is_timeout(start, SECOND)) {
		tmp = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
		/* Test if the speed change finished. */
		if (!(tmp & PORT_LOGIC_SPEED_CHANGE))
			return 0;
	}

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

static void imx6_pcie_ltssm_enable(struct device_d *dev)
{
	struct imx6_pcie *imx6_pcie = dev->priv;
	u32 gpr12;

	switch (imx6_pcie->drvdata->variant) {
	case IMX6Q:
	case IMX6QP:
		gpr12 = readl(imx6_pcie->iomuxc_gpr + IOMUXC_GPR12);
		gpr12 |= IMX6Q_GPR12_PCIE_CTL_2;
		writel(gpr12, imx6_pcie->iomuxc_gpr + IOMUXC_GPR12);
		break;
	case IMX7D:
	case IMX8MQ:
		reset_control_deassert(imx6_pcie->apps_reset);
		break;
	}
}

static int imx6_pcie_establish_link(struct imx6_pcie *imx6_pcie)
{
	struct dw_pcie *pci = imx6_pcie->pci;
	struct device_d *dev = pci->dev;
	uint32_t 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 = dw_pcie_readl_dbi(pci, PCIE_RC_LCR);
	tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK;
	tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1;
	dw_pcie_writel_dbi(pci, PCIE_RC_LCR, tmp);

	imx6_pcie_ltssm_enable(dev);

	ret = imx6_pcie_wait_for_link(imx6_pcie);
	if (ret)
		goto err_reset_phy;


	if (imx6_pcie->link_gen == 2) {
		/* Allow Gen2 mode after the link is up. */
		tmp = dw_pcie_readl_dbi(pci, PCIE_RC_LCR);
		tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK;
		tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2;
		dw_pcie_writel_dbi(pci, PCIE_RC_LCR, tmp);

		/*
		 * Start Directed Speed Change so the best possible
		 * speed both link partners support can be negotiated.
		 */
		tmp = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
		tmp |= PORT_LOGIC_SPEED_CHANGE;
		dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, tmp);

		if (imx6_pcie->drvdata->flags &
		    IMX6_PCIE_FLAG_IMX6_SPEED_CHANGE) {
			/*
			 * On i.MX7, DIRECT_SPEED_CHANGE behaves
			 * differently from i.MX6 family when no link
			 * speed transition occurs and we go Gen1 ->
			 * yep, Gen1. The difference is that, in such
			 * case, it will not be cleared by HW which
			 * will cause the following code to report
			 * false failure.
			 */

			ret = imx6_pcie_wait_for_speed_change(imx6_pcie);
			if (ret) {
				dev_err(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(imx6_pcie);
		if (ret) {
			dev_err(dev, "Failed to bring link up!\n");
			goto err_reset_phy;
		}
	} else {
		dev_info(dev, "Link: Gen2 disabled\n");
        }

	tmp = dw_pcie_readl_dbi(pci, PCIE_RC_LCSR);
	dev_info(dev, "Link up, Gen%i\n", (tmp >> 16) & 0xf);
	return 0;

err_reset_phy:
       dev_dbg(dev, "PHY DEBUG_R0=0x%08x DEBUG_R1=0x%08x\n",
               dw_pcie_readl_dbi(pci, PCIE_PHY_DEBUG_R0),
               dw_pcie_readl_dbi(pci, PCIE_PHY_DEBUG_R1));
       imx6_pcie_reset_phy(imx6_pcie);

       return ret;
}

static int imx6_pcie_host_init(struct pcie_port *pp)
{
	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
	struct imx6_pcie *imx6_pcie = to_imx6_pcie(pci);

	imx6_pcie_assert_core_reset(imx6_pcie);
	imx6_pcie_init_phy(imx6_pcie);
	imx6_pcie_deassert_core_reset(imx6_pcie);
	dw_pcie_setup_rc(pp);
	imx6_pcie_establish_link(imx6_pcie);

	return 0;
}

static int imx6_pcie_link_up(struct dw_pcie *pci)
{
	return dw_pcie_readl_dbi(pci, PCIE_PHY_DEBUG_R1) &
		PCIE_PHY_DEBUG_R1_XMLH_LINK_UP;
}

static const struct dw_pcie_ops dw_pcie_ops = {
       .link_up = imx6_pcie_link_up,
};

static const struct dw_pcie_host_ops imx6_pcie_host_ops = {
	.host_init = imx6_pcie_host_init,
};

static int imx6_add_pcie_port(struct imx6_pcie *imx6_pcie,
			      struct device_d *dev)
{
	struct dw_pcie *pci = imx6_pcie->pci;
	struct pcie_port *pp = &pci->pp;
	int ret;

	pp->ops = &imx6_pcie_host_ops;

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

	return 0;
}

static int imx6_pcie_probe(struct device_d *dev)
{
	struct resource *iores;
	struct dw_pcie *pci;
	struct imx6_pcie *imx6_pcie;
	struct device_node *np = dev->device_node;
	int ret;

	imx6_pcie = xzalloc(sizeof(*imx6_pcie));

	pci = xzalloc(sizeof(*pci));
	pci->dev = dev;
	pci->ops = &dw_pcie_ops;

	imx6_pcie->pci = pci;
	imx6_pcie->drvdata = of_device_get_match_data(dev);

	/* Fetch GPIOs */
	imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0);
	if (imx6_pcie->reset_gpio == -EPROBE_DEFER)
		return imx6_pcie->reset_gpio;

	if (gpio_is_valid(imx6_pcie->reset_gpio)) {
		ret = gpio_request_one(imx6_pcie->reset_gpio,
					    GPIOF_OUT_INIT_LOW, "PCIe reset");
		if (ret) {
			dev_err(dev, "unable to get reset gpio\n");
			return ret;
		}
	}

	iores = dev_request_mem_resource(dev, 0);
	if (IS_ERR(iores))
		return PTR_ERR(iores);
	pci->dbi_base = IOMEM(iores->start);

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

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

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


	switch (imx6_pcie->drvdata->variant) {
	case IMX8MQ:
		imx6_pcie->iomuxc_gpr = IOMEM(MX8MQ_IOMUXC_GPR_BASE_ADDR);
		if (iores->start == IMX8MQ_PCIE2_BASE_ADDR)
			imx6_pcie->controller_id = 1;

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

		goto imx7d_init;
	case IMX7D:
		imx6_pcie->iomuxc_gpr = IOMEM(MX7_IOMUXC_GPR_BASE_ADDR);
	imx7d_init:
		imx6_pcie->pciephy_reset = reset_control_get(dev, "pciephy");
		if (IS_ERR(imx6_pcie->pciephy_reset)) {
			dev_err(dev, "Failed to get PCIEPHY reset control\n");
			return PTR_ERR(imx6_pcie->pciephy_reset);
		}

		imx6_pcie->apps_reset = reset_control_get(dev, "apps");
		if (IS_ERR(imx6_pcie->apps_reset)) {
			dev_err(dev, "Failed to get PCIE APPS reset control\n");
			return PTR_ERR(imx6_pcie->apps_reset);
		}
		break;
	default:
		/* Grab GPR config register range */
		imx6_pcie->iomuxc_gpr = IOMEM(MX6_IOMUXC_BASE_ADDR);
		break;
	}


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

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

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

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

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

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

       	dev->priv = imx6_pcie;

	ret = imx6_add_pcie_port(imx6_pcie, dev);
	if (ret < 0)
		return ret;

	return 0;
}

static void imx6_pcie_remove(struct device_d *dev)
{
	struct imx6_pcie *imx6_pcie = dev->priv;

	if (imx6_pcie->drvdata->variant == 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.
		 */
		struct dw_pcie *pci = imx6_pcie->pci;
		u32 gpr12, val;

		val = dw_pcie_readl_dbi(pci, PCIE_PL_PFLR);
		val &= ~PCIE_PL_PFLR_LINK_STATE_MASK;
		val |= PCIE_PL_PFLR_FORCE_LINK;

		data_abort_mask();
		dw_pcie_writel_dbi(pci, PCIE_PL_PFLR, val);
		data_abort_unmask();

		gpr12 = readl(imx6_pcie->iomuxc_gpr + IOMUXC_GPR12);
		gpr12 &= ~IMX6Q_GPR12_PCIE_CTL_2;
		writel(gpr12, imx6_pcie->iomuxc_gpr + IOMUXC_GPR12);
	}

	imx6_pcie_assert_core_reset(imx6_pcie);
}

static const struct imx6_pcie_drvdata drvdata[] = {
	[IMX6Q] = {
		.variant = IMX6Q,
		.flags = IMX6_PCIE_FLAG_IMX6_PHY |
			 IMX6_PCIE_FLAG_IMX6_SPEED_CHANGE,
	},
	[IMX6QP] = {
		.variant = IMX6QP,
		.flags = IMX6_PCIE_FLAG_IMX6_PHY |
			 IMX6_PCIE_FLAG_IMX6_SPEED_CHANGE,
	},
	[IMX7D] = {
		.variant = IMX7D,
	},
	[IMX8MQ] = {
		.variant = IMX8MQ,
	},
};

static struct of_device_id imx6_pcie_of_match[] = {
	{ .compatible = "fsl,imx6q-pcie",  .data = &drvdata[IMX6Q],  },
	{ .compatible = "fsl,imx6qp-pcie", .data = &drvdata[IMX6QP], },
	{ .compatible = "fsl,imx7d-pcie",  .data = &drvdata[IMX7D],  },
	{ .compatible = "fsl,imx8mq-pcie", .data = &drvdata[IMX8MQ], } ,
	{},
};

static struct driver_d imx6_pcie_driver = {
	.name = "imx6-pcie",
	.of_compatible = DRV_OF_COMPAT(imx6_pcie_of_match),
	.probe = imx6_pcie_probe,
	.remove = imx6_pcie_remove,
};
device_platform_driver(imx6_pcie_driver);

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