Merge branch 'pci/ctrl/imx6'

- Factor out ref clock disables to match enables (Bjorn Helgaas)

- Collect clock enables in imx6_pcie_clk_enable() (Richard Zhu)

- Propagate regulator and clock errors back to .host_init() caller (Richard
  Zhu)

- Disable i.MX6QDL clock when disabling ref clocks (Richard Zhu)

- Call host init function directly in resume instead of duplicating the
  code (Richard Zhu)

- Turn off regulators when suspending (Richard Zhu)

- Make link being down a non-fatal error so probe doesn't fail (Richard
  Zhu)

- Start link in resume only if it was up before suspend to reduce resume
  time (Richard Zhu)

- Move PHY init and power-on out of clock- and reset-related functions
  (Richard Zhu)

- Rework suspend callback to be more symmetric with resume (Richard Zhu)

- Set PCIE_DBI_RO_WR_EN before writing DBI registers (Richard Zhu)

- Allow speeds faster than Gen2 (Richard Zhu)

* pci/ctrl/imx6:
  PCI: imx6: Support more than Gen2 speed link mode
  PCI: imx6: Set PCIE_DBI_RO_WR_EN before writing DBI registers
  PCI: imx6: Reformat suspend callback to keep symmetric with resume
  PCI: imx6: Move the imx6_pcie_ltssm_disable() earlier
  PCI: imx6: Disable clocks in reverse order of enable
  PCI: imx6: Do not hide PHY driver callbacks and refine the error handling
  PCI: imx6: Reduce resume time by only starting link if it was up before suspend
  PCI: imx6: Mark the link down as non-fatal error
  PCI: imx6: Move regulator enable out of imx6_pcie_deassert_core_reset()
  PCI: imx6: Turn off regulator when system is in suspend mode
  PCI: imx6: Call host init function directly in resume
  PCI: imx6: Disable i.MX6QDL clock when disabling ref clocks
  PCI: imx6: Propagate .host_init() errors to caller
  PCI: imx6: Collect clock enables in imx6_pcie_clk_enable()
  PCI: imx6: Factor out ref clock disable to match enable
  PCI: imx6: Move imx6_pcie_clk_disable() earlier
  PCI: imx6: Move imx6_pcie_enable_ref_clk() earlier
  PCI: imx6: Move PHY management functions together
  PCI: imx6: Move imx6_pcie_grp_offset(), imx6_pcie_configure_type() earlier
  PCI: imx6: Convert to NOIRQ_SYSTEM_SLEEP_PM_OPS()

drivers/pci/controller/dwc/pci-imx6.c

@@ -67,6 +67,7 @@ struct imx6_pcie {
 	struct dw_pcie		*pci;
 	int			reset_gpio;
 	bool			gpio_active_high;
+	bool			link_is_up;
 	struct clk		*pcie_bus;
 	struct clk		*pcie_phy;
 	struct clk		*pcie_inbound_axi;
@@ -146,6 +147,31 @@ struct imx6_pcie {
 #define PHY_RX_OVRD_IN_LO_RX_DATA_EN		BIT(5)
 #define PHY_RX_OVRD_IN_LO_RX_PLL_EN		BIT(3)
 
+static unsigned int imx6_pcie_grp_offset(const struct imx6_pcie *imx6_pcie)
+{
+	WARN_ON(imx6_pcie->drvdata->variant != IMX8MQ &&
+		imx6_pcie->drvdata->variant != IMX8MM);
+	return imx6_pcie->controller_id == 1 ? IOMUXC_GPR16 : IOMUXC_GPR14;
+}
+
+static void imx6_pcie_configure_type(struct imx6_pcie *imx6_pcie)
+{
+	unsigned int mask, val;
+
+	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);
+	}
+
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, mask, val);
+}
+
 static int pcie_phy_poll_ack(struct imx6_pcie *imx6_pcie, bool exp_val)
 {
 	struct dw_pcie *pci = imx6_pcie->pci;
@@ -271,6 +297,134 @@ static int pcie_phy_write(struct imx6_pcie *imx6_pcie, int addr, u16 data)
 	return 0;
 }
 
+static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
+{
+	switch (imx6_pcie->drvdata->variant) {
+	case IMX8MM:
+		/*
+		 * The PHY initialization had been done in the PHY
+		 * driver, break here directly.
+		 */
+		break;
+	case IMX8MQ:
+		/*
+		 * TODO: Currently this code assumes external
+		 * oscillator is being used
+		 */
+		regmap_update_bits(imx6_pcie->iomuxc_gpr,
+				   imx6_pcie_grp_offset(imx6_pcie),
+				   IMX8MQ_GPR_PCIE_REF_USE_PAD,
+				   IMX8MQ_GPR_PCIE_REF_USE_PAD);
+		/*
+		 * Regarding the datasheet, the PCIE_VPH is suggested
+		 * to be 1.8V. If the PCIE_VPH is supplied by 3.3V, the
+		 * VREG_BYPASS should be cleared to zero.
+		 */
+		if (imx6_pcie->vph &&
+		    regulator_get_voltage(imx6_pcie->vph) > 3000000)
+			regmap_update_bits(imx6_pcie->iomuxc_gpr,
+					   imx6_pcie_grp_offset(imx6_pcie),
+					   IMX8MQ_GPR_PCIE_VREG_BYPASS,
+					   0);
+		break;
+	case IMX7D:
+		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
+				   IMX7D_GPR12_PCIE_PHY_REFCLK_SEL, 0);
+		break;
+	case IMX6SX:
+		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
+				   IMX6SX_GPR12_PCIE_RX_EQ_MASK,
+				   IMX6SX_GPR12_PCIE_RX_EQ_2);
+		fallthrough;
+	default:
+		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_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);
+		break;
+	}
+
+	imx6_pcie_configure_type(imx6_pcie);
+}
+
+static void imx7d_pcie_wait_for_phy_pll_lock(struct imx6_pcie *imx6_pcie)
+{
+	u32 val;
+	struct device *dev = imx6_pcie->pci->dev;
+
+	if (regmap_read_poll_timeout(imx6_pcie->iomuxc_gpr,
+				     IOMUXC_GPR22, val,
+				     val & IMX7D_GPR22_PCIE_PHY_PLL_LOCKED,
+				     PHY_PLL_LOCK_WAIT_USLEEP_MAX,
+				     PHY_PLL_LOCK_WAIT_TIMEOUT))
+		dev_err(dev, "PCIe PLL lock timeout\n");
+}
+
+static int imx6_setup_phy_mpll(struct imx6_pcie *imx6_pcie)
+{
+	unsigned long phy_rate = clk_get_rate(imx6_pcie->pcie_phy);
+	int mult, div;
+	u16 val;
+
+	if (!(imx6_pcie->drvdata->flags & IMX6_PCIE_FLAG_IMX6_PHY))
+		return 0;
+
+	switch (phy_rate) {
+	case 125000000:
+		/*
+		 * The default settings of the MPLL are for a 125MHz input
+		 * clock, so no need to reconfigure anything in that case.
+		 */
+		return 0;
+	case 100000000:
+		mult = 25;
+		div = 0;
+		break;
+	case 200000000:
+		mult = 25;
+		div = 1;
+		break;
+	default:
+		dev_err(imx6_pcie->pci->dev,
+			"Unsupported PHY reference clock rate %lu\n", phy_rate);
+		return -EINVAL;
+	}
+
+	pcie_phy_read(imx6_pcie, PCIE_PHY_MPLL_OVRD_IN_LO, &val);
+	val &= ~(PCIE_PHY_MPLL_MULTIPLIER_MASK <<
+		 PCIE_PHY_MPLL_MULTIPLIER_SHIFT);
+	val |= mult << PCIE_PHY_MPLL_MULTIPLIER_SHIFT;
+	val |= PCIE_PHY_MPLL_MULTIPLIER_OVRD;
+	pcie_phy_write(imx6_pcie, PCIE_PHY_MPLL_OVRD_IN_LO, val);
+
+	pcie_phy_read(imx6_pcie, PCIE_PHY_ATEOVRD, &val);
+	val &= ~(PCIE_PHY_ATEOVRD_REF_CLKDIV_MASK <<
+		 PCIE_PHY_ATEOVRD_REF_CLKDIV_SHIFT);
+	val |= div << PCIE_PHY_ATEOVRD_REF_CLKDIV_SHIFT;
+	val |= PCIE_PHY_ATEOVRD_EN;
+	pcie_phy_write(imx6_pcie, PCIE_PHY_ATEOVRD, val);
+
+	return 0;
+}
+
 static void imx6_pcie_reset_phy(struct imx6_pcie *imx6_pcie)
 {
 	u16 tmp;
@@ -367,61 +521,6 @@ static int imx6_pcie_attach_pd(struct device *dev)
 	return 0;
 }
 
-static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
-{
-	struct device *dev = imx6_pcie->pci->dev;
-
-	switch (imx6_pcie->drvdata->variant) {
-	case IMX7D:
-	case IMX8MQ:
-		reset_control_assert(imx6_pcie->pciephy_reset);
-		fallthrough;
-	case IMX8MM:
-		reset_control_assert(imx6_pcie->apps_reset);
-		break;
-	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:
-		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;
-	}
-
-	if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
-		int ret = regulator_disable(imx6_pcie->vpcie);
-
-		if (ret)
-			dev_err(dev, "failed to disable vpcie regulator: %d\n",
-				ret);
-	}
-
-	/* 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);
-}
-
-static unsigned int imx6_pcie_grp_offset(const struct imx6_pcie *imx6_pcie)
-{
-	WARN_ON(imx6_pcie->drvdata->variant != IMX8MQ &&
-		imx6_pcie->drvdata->variant != IMX8MM);
-	return imx6_pcie->controller_id == 1 ? IOMUXC_GPR16 : IOMUXC_GPR14;
-}
-
 static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
 {
 	struct dw_pcie *pci = imx6_pcie->pci;
@@ -482,38 +581,44 @@ static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
 	return ret;
 }
 
-static void imx7d_pcie_wait_for_phy_pll_lock(struct imx6_pcie *imx6_pcie)
+static void imx6_pcie_disable_ref_clk(struct imx6_pcie *imx6_pcie)
 {
-	u32 val;
-	struct device *dev = imx6_pcie->pci->dev;
-
-	if (regmap_read_poll_timeout(imx6_pcie->iomuxc_gpr,
-				     IOMUXC_GPR22, val,
-				     val & IMX7D_GPR22_PCIE_PHY_PLL_LOCKED,
-				     PHY_PLL_LOCK_WAIT_USLEEP_MAX,
-				     PHY_PLL_LOCK_WAIT_TIMEOUT))
-		dev_err(dev, "PCIe PLL lock timeout\n");
+	switch (imx6_pcie->drvdata->variant) {
+	case IMX6SX:
+		clk_disable_unprepare(imx6_pcie->pcie_inbound_axi);
+		break;
+	case IMX6QP:
+	case IMX6Q:
+		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
+				IMX6Q_GPR1_PCIE_REF_CLK_EN, 0);
+		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
+				IMX6Q_GPR1_PCIE_TEST_PD,
+				IMX6Q_GPR1_PCIE_TEST_PD);
+		break;
+	case IMX7D:
+		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
+				   IMX7D_GPR12_PCIE_PHY_REFCLK_SEL,
+				   IMX7D_GPR12_PCIE_PHY_REFCLK_SEL);
+		break;
+	case IMX8MM:
+	case IMX8MQ:
+		clk_disable_unprepare(imx6_pcie->pcie_aux);
+		break;
+	default:
+		break;
+	}
 }
 
-static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
+static int imx6_pcie_clk_enable(struct imx6_pcie *imx6_pcie)
 {
 	struct dw_pcie *pci = imx6_pcie->pci;
 	struct device *dev = pci->dev;
 	int ret;
 
-	if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) {
-		ret = regulator_enable(imx6_pcie->vpcie);
-		if (ret) {
-			dev_err(dev, "failed to enable vpcie regulator: %d\n",
-				ret);
-			return;
-		}
-	}
-
 	ret = clk_prepare_enable(imx6_pcie->pcie_phy);
 	if (ret) {
 		dev_err(dev, "unable to enable pcie_phy clock\n");
-		goto err_pcie_phy;
+		return ret;
 	}
 
 	ret = clk_prepare_enable(imx6_pcie->pcie_bus);
@@ -534,24 +639,74 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 		goto err_ref_clk;
 	}
 
-	switch (imx6_pcie->drvdata->variant) {
-	case IMX8MM:
-		if (phy_power_on(imx6_pcie->phy))
-			dev_err(dev, "unable to power on PHY\n");
-		break;
-	default:
-		break;
-	}
 	/* allow the clocks to stabilize */
 	usleep_range(200, 500);
+	return 0;
 
-	switch (imx6_pcie->drvdata->variant) {
-	case IMX8MQ:
-		reset_control_deassert(imx6_pcie->pciephy_reset);
-		break;
+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);
+
+	return ret;
+}
+
+static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_pcie)
+{
+	imx6_pcie_disable_ref_clk(imx6_pcie);
+	clk_disable_unprepare(imx6_pcie->pcie);
+	clk_disable_unprepare(imx6_pcie->pcie_bus);
+	clk_disable_unprepare(imx6_pcie->pcie_phy);
+}
+
+static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
+{
+	switch (imx6_pcie->drvdata->variant) {
+	case IMX7D:
+	case IMX8MQ:
+		reset_control_assert(imx6_pcie->pciephy_reset);
+		fallthrough;
 	case IMX8MM:
-		if (phy_init(imx6_pcie->phy))
-			dev_err(dev, "waiting for phy ready timeout!\n");
+		reset_control_assert(imx6_pcie->apps_reset);
+		break;
+	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:
+		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;
+	}
+
+	/* 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);
+}
+
+static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
+{
+	struct dw_pcie *pci = imx6_pcie->pci;
+	struct device *dev = pci->dev;
+
+	switch (imx6_pcie->drvdata->variant) {
+	case IMX8MQ:
+		reset_control_deassert(imx6_pcie->pciephy_reset);
 		break;
 	case IMX7D:
 		reset_control_deassert(imx6_pcie->pciephy_reset);
@@ -588,6 +743,7 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 		usleep_range(200, 500);
 		break;
 	case IMX6Q:		/* Nothing to do */
+	case IMX8MM:
 		break;
 	}
 
@@ -600,153 +756,6 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 		msleep(100);
 	}
 
-	return;
-
-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:
-	if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
-		ret = regulator_disable(imx6_pcie->vpcie);
-		if (ret)
-			dev_err(dev, "failed to disable vpcie regulator: %d\n",
-				ret);
-	}
-}
-
-static void imx6_pcie_configure_type(struct imx6_pcie *imx6_pcie)
-{
-	unsigned int mask, val;
-
-	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);
-	}
-
-	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, mask, val);
-}
-
-static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
-{
-	switch (imx6_pcie->drvdata->variant) {
-	case IMX8MM:
-		/*
-		 * The PHY initialization had been done in the PHY
-		 * driver, break here directly.
-		 */
-		break;
-	case IMX8MQ:
-		/*
-		 * TODO: Currently this code assumes external
-		 * oscillator is being used
-		 */
-		regmap_update_bits(imx6_pcie->iomuxc_gpr,
-				   imx6_pcie_grp_offset(imx6_pcie),
-				   IMX8MQ_GPR_PCIE_REF_USE_PAD,
-				   IMX8MQ_GPR_PCIE_REF_USE_PAD);
-		/*
-		 * Regarding the datasheet, the PCIE_VPH is suggested
-		 * to be 1.8V. If the PCIE_VPH is supplied by 3.3V, the
-		 * VREG_BYPASS should be cleared to zero.
-		 */
-		if (imx6_pcie->vph &&
-		    regulator_get_voltage(imx6_pcie->vph) > 3000000)
-			regmap_update_bits(imx6_pcie->iomuxc_gpr,
-					   imx6_pcie_grp_offset(imx6_pcie),
-					   IMX8MQ_GPR_PCIE_VREG_BYPASS,
-					   0);
-		break;
-	case IMX7D:
-		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
-				   IMX7D_GPR12_PCIE_PHY_REFCLK_SEL, 0);
-		break;
-	case IMX6SX:
-		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
-				   IMX6SX_GPR12_PCIE_RX_EQ_MASK,
-				   IMX6SX_GPR12_PCIE_RX_EQ_2);
-		fallthrough;
-	default:
-		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_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);
-		break;
-	}
-
-	imx6_pcie_configure_type(imx6_pcie);
-}
-
-static int imx6_setup_phy_mpll(struct imx6_pcie *imx6_pcie)
-{
-	unsigned long phy_rate = clk_get_rate(imx6_pcie->pcie_phy);
-	int mult, div;
-	u16 val;
-
-	if (!(imx6_pcie->drvdata->flags & IMX6_PCIE_FLAG_IMX6_PHY))
-		return 0;
-
-	switch (phy_rate) {
-	case 125000000:
-		/*
-		 * The default settings of the MPLL are for a 125MHz input
-		 * clock, so no need to reconfigure anything in that case.
-		 */
-		return 0;
-	case 100000000:
-		mult = 25;
-		div = 0;
-		break;
-	case 200000000:
-		mult = 25;
-		div = 1;
-		break;
-	default:
-		dev_err(imx6_pcie->pci->dev,
-			"Unsupported PHY reference clock rate %lu\n", phy_rate);
-		return -EINVAL;
-	}
-
-	pcie_phy_read(imx6_pcie, PCIE_PHY_MPLL_OVRD_IN_LO, &val);
-	val &= ~(PCIE_PHY_MPLL_MULTIPLIER_MASK <<
-		 PCIE_PHY_MPLL_MULTIPLIER_SHIFT);
-	val |= mult << PCIE_PHY_MPLL_MULTIPLIER_SHIFT;
-	val |= PCIE_PHY_MPLL_MULTIPLIER_OVRD;
-	pcie_phy_write(imx6_pcie, PCIE_PHY_MPLL_OVRD_IN_LO, val);
-
-	pcie_phy_read(imx6_pcie, PCIE_PHY_ATEOVRD, &val);
-	val &= ~(PCIE_PHY_ATEOVRD_REF_CLKDIV_MASK <<
-		 PCIE_PHY_ATEOVRD_REF_CLKDIV_SHIFT);
-	val |= div << PCIE_PHY_ATEOVRD_REF_CLKDIV_SHIFT;
-	val |= PCIE_PHY_ATEOVRD_EN;
-	pcie_phy_write(imx6_pcie, PCIE_PHY_ATEOVRD, val);
-
 	return 0;
 }
 
@@ -789,6 +798,25 @@ static void imx6_pcie_ltssm_enable(struct device *dev)
 	}
 }
 
+static void imx6_pcie_ltssm_disable(struct device *dev)
+{
+	struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev);
+
+	switch (imx6_pcie->drvdata->variant) {
+	case IMX6Q:
+	case IMX6SX:
+	case IMX6QP:
+		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
+				   IMX6Q_GPR12_PCIE_CTL_2, 0);
+		break;
+	case IMX7D:
+	case IMX8MQ:
+	case IMX8MM:
+		reset_control_assert(imx6_pcie->apps_reset);
+		break;
+	}
+}
+
 static int imx6_pcie_start_link(struct dw_pcie *pci)
 {
 	struct imx6_pcie *imx6_pcie = to_imx6_pcie(pci);
@@ -802,21 +830,26 @@ static int imx6_pcie_start_link(struct dw_pcie *pci)
 	 * started in Gen2 mode, there is a possibility the devices on the
 	 * bus will not be detected at all.  This happens with PCIe switches.
 	 */
+	dw_pcie_dbi_ro_wr_en(pci);
 	tmp = dw_pcie_readl_dbi(pci, offset + PCI_EXP_LNKCAP);
 	tmp &= ~PCI_EXP_LNKCAP_SLS;
 	tmp |= PCI_EXP_LNKCAP_SLS_2_5GB;
 	dw_pcie_writel_dbi(pci, offset + PCI_EXP_LNKCAP, tmp);
+	dw_pcie_dbi_ro_wr_dis(pci);
 
 	/* Start LTSSM. */
 	imx6_pcie_ltssm_enable(dev);
 
-	dw_pcie_wait_for_link(pci);
+	ret = dw_pcie_wait_for_link(pci);
+	if (ret)
+		goto err_reset_phy;
 
-	if (pci->link_gen == 2) {
-		/* Allow Gen2 mode after the link is up. */
+	if (pci->link_gen > 1) {
+		/* Allow faster modes after the link is up */
+		dw_pcie_dbi_ro_wr_en(pci);
 		tmp = dw_pcie_readl_dbi(pci, offset + PCI_EXP_LNKCAP);
 		tmp &= ~PCI_EXP_LNKCAP_SLS;
-		tmp |= PCI_EXP_LNKCAP_SLS_5_0GB;
+		tmp |= pci->link_gen;
 		dw_pcie_writel_dbi(pci, offset + PCI_EXP_LNKCAP, tmp);
 
 		/*
@@ -826,6 +859,7 @@ static int imx6_pcie_start_link(struct dw_pcie *pci)
 		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);
+		dw_pcie_dbi_ro_wr_dis(pci);
 
 		if (imx6_pcie->drvdata->flags &
 		    IMX6_PCIE_FLAG_IMX6_SPEED_CHANGE) {
@@ -846,34 +880,110 @@ static int imx6_pcie_start_link(struct dw_pcie *pci)
 		}
 
 		/* Make sure link training is finished as well! */
-		dw_pcie_wait_for_link(pci);
+		ret = dw_pcie_wait_for_link(pci);
+		if (ret)
+			goto err_reset_phy;
 	} else {
-		dev_info(dev, "Link: Gen2 disabled\n");
+		dev_info(dev, "Link: Only Gen1 is enabled\n");
 	}
 
+	imx6_pcie->link_is_up = true;
 	tmp = dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKSTA);
 	dev_info(dev, "Link up, Gen%i\n", tmp & PCI_EXP_LNKSTA_CLS);
 	return 0;
 
 err_reset_phy:
+	imx6_pcie->link_is_up = false;
 	dev_dbg(dev, "PHY DEBUG_R0=0x%08x DEBUG_R1=0x%08x\n",
 		dw_pcie_readl_dbi(pci, PCIE_PORT_DEBUG0),
 		dw_pcie_readl_dbi(pci, PCIE_PORT_DEBUG1));
 	imx6_pcie_reset_phy(imx6_pcie);
-	return ret;
+	return 0;
+}
+
+static void imx6_pcie_stop_link(struct dw_pcie *pci)
+{
+	struct device *dev = pci->dev;
+
+	/* Turn off PCIe LTSSM */
+	imx6_pcie_ltssm_disable(dev);
 }
 
 static int imx6_pcie_host_init(struct dw_pcie_rp *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct device *dev = pci->dev;
 	struct imx6_pcie *imx6_pcie = to_imx6_pcie(pci);
+	int ret;
+
+	if (imx6_pcie->vpcie) {
+		ret = regulator_enable(imx6_pcie->vpcie);
+		if (ret) {
+			dev_err(dev, "failed to enable vpcie regulator: %d\n",
+				ret);
+			return ret;
+		}
+	}
 
 	imx6_pcie_assert_core_reset(imx6_pcie);
 	imx6_pcie_init_phy(imx6_pcie);
-	imx6_pcie_deassert_core_reset(imx6_pcie);
+
+	ret = imx6_pcie_clk_enable(imx6_pcie);
+	if (ret) {
+		dev_err(dev, "unable to enable pcie clocks: %d\n", ret);
+		goto err_reg_disable;
+	}
+
+	if (imx6_pcie->phy) {
+		ret = phy_power_on(imx6_pcie->phy);
+		if (ret) {
+			dev_err(dev, "pcie PHY power up failed\n");
+			goto err_clk_disable;
+		}
+	}
+
+	ret = imx6_pcie_deassert_core_reset(imx6_pcie);
+	if (ret < 0) {
+		dev_err(dev, "pcie deassert core reset failed: %d\n", ret);
+		goto err_phy_off;
+	}
+
+	if (imx6_pcie->phy) {
+		ret = phy_init(imx6_pcie->phy);
+		if (ret) {
+			dev_err(dev, "waiting for PHY ready timeout!\n");
+			goto err_phy_off;
+		}
+	}
 	imx6_setup_phy_mpll(imx6_pcie);
 
 	return 0;
+
+err_phy_off:
+	if (imx6_pcie->phy)
+		phy_power_off(imx6_pcie->phy);
+err_clk_disable:
+	imx6_pcie_clk_disable(imx6_pcie);
+err_reg_disable:
+	if (imx6_pcie->vpcie)
+		regulator_disable(imx6_pcie->vpcie);
+	return ret;
+}
+
+static void imx6_pcie_host_exit(struct dw_pcie_rp *pp)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct imx6_pcie *imx6_pcie = to_imx6_pcie(pci);
+
+	if (imx6_pcie->phy) {
+		if (phy_power_off(imx6_pcie->phy))
+			dev_err(pci->dev, "unable to power off PHY\n");
+		phy_exit(imx6_pcie->phy);
+	}
+	imx6_pcie_clk_disable(imx6_pcie);
+
+	if (imx6_pcie->vpcie)
+		regulator_disable(imx6_pcie->vpcie);
 }
 
 static const struct dw_pcie_host_ops imx6_pcie_host_ops = {
@@ -884,26 +994,6 @@ static const struct dw_pcie_ops dw_pcie_ops = {
 	.start_link = imx6_pcie_start_link,
 };
 
-#ifdef CONFIG_PM_SLEEP
-static void imx6_pcie_ltssm_disable(struct device *dev)
-{
-	struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev);
-
-	switch (imx6_pcie->drvdata->variant) {
-	case IMX6SX:
-	case IMX6QP:
-		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
-				   IMX6Q_GPR12_PCIE_CTL_2, 0);
-		break;
-	case IMX7D:
-	case IMX8MM:
-		reset_control_assert(imx6_pcie->apps_reset);
-		break;
-	default:
-		dev_err(dev, "ltssm_disable not supported\n");
-	}
-}
-
 static void imx6_pcie_pm_turnoff(struct imx6_pcie *imx6_pcie)
 {
 	struct device *dev = imx6_pcie->pci->dev;
@@ -941,49 +1031,17 @@ static void imx6_pcie_pm_turnoff(struct imx6_pcie *imx6_pcie)
 	usleep_range(1000, 10000);
 }
 
-static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_pcie)
-{
-	clk_disable_unprepare(imx6_pcie->pcie);
-	clk_disable_unprepare(imx6_pcie->pcie_phy);
-	clk_disable_unprepare(imx6_pcie->pcie_bus);
-
-	switch (imx6_pcie->drvdata->variant) {
-	case IMX6SX:
-		clk_disable_unprepare(imx6_pcie->pcie_inbound_axi);
-		break;
-	case IMX7D:
-		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
-				   IMX7D_GPR12_PCIE_PHY_REFCLK_SEL,
-				   IMX7D_GPR12_PCIE_PHY_REFCLK_SEL);
-		break;
-	case IMX8MQ:
-	case IMX8MM:
-		clk_disable_unprepare(imx6_pcie->pcie_aux);
-		break;
-	default:
-		break;
-	}
-}
-
 static int imx6_pcie_suspend_noirq(struct device *dev)
 {
 	struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev);
+	struct dw_pcie_rp *pp = &imx6_pcie->pci->pp;
 
 	if (!(imx6_pcie->drvdata->flags & IMX6_PCIE_FLAG_SUPPORTS_SUSPEND))
 		return 0;
 
 	imx6_pcie_pm_turnoff(imx6_pcie);
-	imx6_pcie_ltssm_disable(dev);
-	imx6_pcie_clk_disable(imx6_pcie);
-	switch (imx6_pcie->drvdata->variant) {
-	case IMX8MM:
-		if (phy_power_off(imx6_pcie->phy))
-			dev_err(dev, "unable to power off PHY\n");
-		phy_exit(imx6_pcie->phy);
-		break;
-	default:
-		break;
-	}
+	imx6_pcie_stop_link(imx6_pcie->pci);
+	imx6_pcie_host_exit(pp);
 
 	return 0;
 }
@@ -997,21 +1055,19 @@ static int imx6_pcie_resume_noirq(struct device *dev)
 	if (!(imx6_pcie->drvdata->flags & IMX6_PCIE_FLAG_SUPPORTS_SUSPEND))
 		return 0;
 
-	imx6_pcie_assert_core_reset(imx6_pcie);
-	imx6_pcie_init_phy(imx6_pcie);
-	imx6_pcie_deassert_core_reset(imx6_pcie);
+	ret = imx6_pcie_host_init(pp);
+	if (ret)
+		return ret;
 	dw_pcie_setup_rc(pp);
 
-	ret = imx6_pcie_start_link(imx6_pcie->pci);
-	if (ret < 0)
-		dev_info(dev, "pcie link is down after resume.\n");
+	if (imx6_pcie->link_is_up)
+		imx6_pcie_start_link(imx6_pcie->pci);
 
 	return 0;
 }
-#endif
 
 static const struct dev_pm_ops imx6_pcie_pm_ops = {
-	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx6_pcie_suspend_noirq,
+	NOIRQ_SYSTEM_SLEEP_PM_OPS(imx6_pcie_suspend_noirq,
 				  imx6_pcie_resume_noirq)
 };