[PATCH v13 0/15] PCI: imx6: refine codes and add the error propagation

[PATCH v13 0/15] PCI: imx6: refine codes and add the error propagation

[Richard Zhu]

This series patches refine pci-imx6 driver and do the following main changes.
- Encapsulate the clock enable into one standalone function
- Add the error propagation from host_init and resume
- Turn off regulator when the system is in suspend mode
- Let the probe successfully when link never comes up
- Do not hide the phy driver callbacks in core reset and clk_enable.
BTW, this series are verified on i.MX8MM EVK board when one NVME is used.

Main changes from v12 to v13:
- Call imx6_pcie_host_init() instead of duplicating codes in resume.
- Move the regulator enable out of imx6_pcie_deassert_core_reset().
  Re-format the error handling in imx6_pcie_deassert_core_reset()
  and imx6_pcie_host_init() accordingly.

Main changes from v11 to v12 issued by Bjorn:
- Add four intro patches to move code around to collect similar things
  (PHY management, reset management) together.  This makes the first
  diff to collect clock enables simpler because it's not cluttered with
  unrelated things that didn't actually change.
- Factor out ref clock disables so the disable function structure matches
  the enable structure.
- Drop unused "ret" from "Reduce resume time ..." to avoid bisection
  hole, then add it back in "Do not hide phy driver ..." where we start
  using it again.
- Add patch to make imx6_pcie_clk_disable() symmetric with
  imx6_pcie_clk_enable() in terms of enable/disable ordering.

Main changes from v10 to v11:
No code changes, just do the following operations refer to Bjorn's comments.
  - Split #6 patch into two patches.
  - Rebase to v5.19-rc1 based on for-next branch of Shawn's git.

Main changes from v9 to v10:
- Add the "Reviewed-by: Lucas Stach <l.stach@pengutronix.de>" tag into #3
  and #4 patches.
- Refer to Bjorn's comments:
  - refine the commit of the first patch
  - keep alignment of the message format in the second patch
  - More specific commit and subject of the #5 and #7 patches.
- Move the regualtor_disable into suspend, turn off the regulator when bus
  is powered off and system in suspend mode.
- Let the driver probe successfully, return zero in imx6_pcie_start_link()
  when PCIe link is down. 
  In this link down scenario, only start the PCIe link training in resume
  when the link is up before system suspend to avoid the long latency in
  the link training period.
- Don't hide phy driver callbacks in core reset and clk_enable, and refine
  the error handling accordingly.
- Drop the #8 patch of v9 series, since the clocks and powers are not gated
  off anymore when link is down.

Main changes from v8 to v9:
- Don't change pcie-designware codes, and do the error exit process only in
  pci-imx6 driver internally.
- Move the phy driver callbacks to the proper places

Main changes from v7 to v8:
Regarding Bjorn's review comments.
- Align the format of the dev_info message and refine commit log of
  #6/7/8 patches.
- Rename the err_reset_phy label, since there is no PHY reset in the out

Main changes from v6 to v7:
- Keep the regulator usage counter balance in the #5 patch of v6 series.

Main changes from v5 to v6:
- Refer to the following discussion with Fabio, fix the dump by his patch.
  https://patchwork.kernel.org/project/linux-pci/patch/1641368602-20401-6-git-send-email-hongxing.zhu@nxp.com/
  Refine and rebase this patch-set after Fabio' dump fix patch is merged.
- Add one new #4 patch to disable i.MX6QDL REF clock too when disable clocks
- Split the regulator refine codes into one standalone patch #5 in this version.

Main changes from v4 to v5:
- Since i.MX8MM PCIe support had been merged. Based on Lorenzo's git repos,
  resend the patch-set after rebase.

Main changes from v3 to v4:
- Regarding Mark's comments, delete the regulator_is_enabled() check.
- Squash #3 and #6 of v3 patch into #5 patch of v4 set.

Main changes from v2 to v3:
- Add "Reviewed-by: Lucas Stach <l.stach@pengutronix.de>" tag into
  first two patches.
- Add a Fixes tag into #3 patch.
- Split the #4 of v2 to two patches, one is clock disable codes move,
  the other one is the acutal clock unbalance fix.
- Add a new host_exit() callback into dw_pcie_host_ops, then it could be
  invoked to handle the unbalance issue in the error handling after
  host_init() function when link is down.
- Add a new host_exit() callback for i.MX PCIe driver to handle this case
  in the error handling after host_init.

Main changes from v1 to v2:
Regarding Lucas' comments.
  - Move the placement of the new imx6_pcie_clk_enable() to avoid the
    forward declarition.
  - Seperate the second patch of v1 patch-set to three patches.
  - Use the module_param to replace the kernel command line.
Regarding Bjorn's comments:
  - Use the cover-letter for a multi-patch series.
  - Correct the subject line, and refine the commit logs. For example,
    remove the timestamp of the logs.

Bjorn Helgaas (5):
  PCI: imx6: Move imx6_pcie_grp_offset(), imx6_pcie_configure_type()
    earlier
  PCI: imx6: Move PHY management functions together
  PCI: imx6: Move imx6_pcie_enable_ref_clk() earlier
  PCI: imx6: Factor out ref clock disable to match enable
  PCI: imx6: Disable clocks in reverse order of enable

Richard Zhu (10):
  PCI: imx6: Move imx6_pcie_clk_disable() earlier
  PCI: imx6: Collect clock enables in imx6_pcie_clk_enable()
  PCI: imx6: Propagate .host_init() errors to caller
  PCI: imx6: Disable i.MX6QDL clock when disabling ref clocks
  PCI: imx6: Call host init function directly in resume
  PCI: imx6: Turn off regulator when system is in suspend mode
  PCI: imx6: Move regulator enable out of
    imx6_pcie_deassert_core_reset()
  PCI: imx6: Mark the link down as non-fatal error
  PCI: imx6: Reduce resume time by only starting link if it was up
    before suspend
  PCI: imx6: Do not hide phy driver callbacks and refine the error
    handling

drivers/pci/controller/dwc/pci-imx6.c | 574 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------------------------------------------------------------------------------------------------
1 file changed, 308 insertions(+), 266 deletions(-)

[PATCH v13 01/15] PCI: imx6: Move imx6_pcie_grp_offset(), imx6_pcie_configure_type() earlier

[Richard Zhu]

From: Bjorn Helgaas <bhelgaas@google.com>

Move imx6_pcie_grp_offset() and imx6_pcie_configure_type() earlier in the
file since they depend on nothing and are used by several other functions
that will be moved earlier.  No functional change intended.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Richard Zhu <hongxing.zhu@nxp.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 50 +++++++++++++--------------
 1 file changed, 25 insertions(+), 25 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 7a285fb0f619..8653ca8cbfb9 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -146,6 +146,31 @@ 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;
@@ -415,13 +440,6 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
 					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;
@@ -617,24 +635,6 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 	}
 }
 
-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) {
-- 
2.25.1

[PATCH v13 02/15] PCI: imx6: Move PHY management functions together

[Richard Zhu]

From: Bjorn Helgaas <bhelgaas@google.com>

Collect imx6_pcie_init_phy(), imx7d_pcie_wait_for_phy_pll_lock(), and
imx6_setup_phy_mpll() earlier with other PHY-related code.  No functional
change intended.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Richard Zhu <hongxing.zhu@nxp.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 256 +++++++++++++-------------
 1 file changed, 128 insertions(+), 128 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 8653ca8cbfb9..e63eb6380020 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -296,6 +296,134 @@ 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;
@@ -500,19 +628,6 @@ 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)
-{
-	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 void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 {
 	struct dw_pcie *pci = imx6_pcie->pci;
@@ -635,121 +750,6 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 	}
 }
 
-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;
-}
-
 static int imx6_pcie_wait_for_speed_change(struct imx6_pcie *imx6_pcie)
 {
 	struct dw_pcie *pci = imx6_pcie->pci;
-- 
2.25.1

[PATCH v13 03/15] PCI: imx6: Move imx6_pcie_enable_ref_clk() earlier

[Richard Zhu]

From: Bjorn Helgaas <bhelgaas@google.com>

Move imx6_pcie_enable_ref_clk() earlier so it's not in the middle between
imx6_pcie_assert_core_reset() and imx6_pcie_deassert_core_reset().  No
functional change intended.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Richard Zhu <hongxing.zhu@nxp.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 96 +++++++++++++--------------
 1 file changed, 48 insertions(+), 48 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index e63eb6380020..a6d2b907d42b 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -520,54 +520,6 @@ 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 int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
 {
 	struct dw_pcie *pci = imx6_pcie->pci;
@@ -628,6 +580,54 @@ static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
 	return ret;
 }
 
+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 void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 {
 	struct dw_pcie *pci = imx6_pcie->pci;
-- 
2.25.1

[PATCH v13 04/15] PCI: imx6: Move imx6_pcie_clk_disable() earlier

[Richard Zhu]

Move imx6_pcie_clk_disable() earlier to be near other clock-related
functions.  No functional change intended.

[bhelgaas: reorder patch so pure moves are earlier]
Link: https://lore.kernel.org/r/1655189942-12678-4-git-send-email-hongxing.z
hu@nxp.com
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
---
 drivers/pci/controller/dwc/pci-imx6.c | 48 +++++++++++++--------------
 1 file changed, 24 insertions(+), 24 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index a6d2b907d42b..38f208eea2d7 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -580,6 +580,30 @@ static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
 	return ret;
 }
 
+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 void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
 {
 	struct device *dev = imx6_pcie->pci->dev;
@@ -941,30 +965,6 @@ 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);
-- 
2.25.1

[PATCH v13 05/15] PCI: imx6: Factor out ref clock disable to match enable

[Richard Zhu]

From: Bjorn Helgaas <bhelgaas@google.com>

The PCIe ref clocks are specific to different variants.  The enables are
already split out into imx6_pcie_enable_ref_clk(), but the disables were
combined with the more generic bus/phy/pcie clock disables in
imx6_pcie_clk_disable().

Split out the variant-specific disables into imx6_pcie_disable_ref_clk() to
match imx6_pcie_enable_ref_clk().

No functional change intended.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Richard Zhu <hongxing.zhu@nxp.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 38f208eea2d7..f458461880dc 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -580,12 +580,8 @@ static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
 	return ret;
 }
 
-static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_pcie)
+static void imx6_pcie_disable_ref_clk(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);
@@ -595,8 +591,8 @@ static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_pcie)
 				   IMX7D_GPR12_PCIE_PHY_REFCLK_SEL,
 				   IMX7D_GPR12_PCIE_PHY_REFCLK_SEL);
 		break;
-	case IMX8MQ:
 	case IMX8MM:
+	case IMX8MQ:
 		clk_disable_unprepare(imx6_pcie->pcie_aux);
 		break;
 	default:
@@ -604,6 +600,14 @@ static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_pcie)
 	}
 }
 
+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);
+	imx6_pcie_disable_ref_clk(imx6_pcie);
+}
+
 static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
 {
 	struct device *dev = imx6_pcie->pci->dev;
-- 
2.25.1

[PATCH v13 06/15] PCI: imx6: Collect clock enables in imx6_pcie_clk_enable()

[Richard Zhu]

Encapsulate the i.MX PCIe clock enable operations into one standalone
function, imx6_pcie_clk_enable().  No functional change intended.

[bhelgaas: split pure code moves into separate patches]
Link: https://lore.kernel.org/r/1655189942-12678-2-git-send-email-hongxing.zhu@nxp.com
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
---
 drivers/pci/controller/dwc/pci-imx6.c | 95 ++++++++++++++++-----------
 1 file changed, 56 insertions(+), 39 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index f458461880dc..ff5829e42ea7 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -600,6 +600,58 @@ static void imx6_pcie_disable_ref_clk(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;
+
+	ret = clk_prepare_enable(imx6_pcie->pcie_phy);
+	if (ret) {
+		dev_err(dev, "unable to enable pcie_phy clock\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(imx6_pcie->pcie_bus);
+	if (ret) {
+		dev_err(dev, "unable to enable pcie_bus clock\n");
+		goto err_pcie_bus;
+	}
+
+	ret = clk_prepare_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;
+	}
+
+	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;
+
+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)
 {
 	clk_disable_unprepare(imx6_pcie->pcie);
@@ -671,40 +723,11 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 		}
 	}
 
-	ret = clk_prepare_enable(imx6_pcie->pcie_phy);
-	if (ret) {
-		dev_err(dev, "unable to enable pcie_phy clock\n");
-		goto err_pcie_phy;
-	}
-
-	ret = clk_prepare_enable(imx6_pcie->pcie_bus);
-	if (ret) {
-		dev_err(dev, "unable to enable pcie_bus clock\n");
-		goto err_pcie_bus;
-	}
-
-	ret = clk_prepare_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);
+	ret = imx6_pcie_clk_enable(imx6_pcie);
 	if (ret) {
-		dev_err(dev, "unable to enable pcie ref clock\n");
-		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;
+		dev_err(dev, "unable to enable pcie clocks: %d\n", ret);
+		goto err_clks;
 	}
-	/* allow the clocks to stabilize */
-	usleep_range(200, 500);
 
 	switch (imx6_pcie->drvdata->variant) {
 	case IMX8MQ:
@@ -763,13 +786,7 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 
 	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:
+err_clks:
 	if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
 		ret = regulator_disable(imx6_pcie->vpcie);
 		if (ret)
-- 
2.25.1

[PATCH v13 07/15] PCI: imx6: Propagate .host_init() errors to caller

[Richard Zhu]

Since dw_pcie_host_init() checks for errors from ops->host_init(),
check for errors when enabling power regulators and clocks and return them.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/1655189942-12678-3-git-send-email-hongxing.zhu@nxp.com
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
---
 drivers/pci/controller/dwc/pci-imx6.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index ff5829e42ea7..78b839e92620 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -708,7 +708,7 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
 					imx6_pcie->gpio_active_high);
 }
 
-static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
+static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 {
 	struct dw_pcie *pci = imx6_pcie->pci;
 	struct device *dev = pci->dev;
@@ -719,7 +719,7 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 		if (ret) {
 			dev_err(dev, "failed to enable vpcie regulator: %d\n",
 				ret);
-			return;
+			return ret;
 		}
 	}
 
@@ -784,7 +784,7 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 		msleep(100);
 	}
 
-	return;
+	return 0;
 
 err_clks:
 	if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
@@ -793,6 +793,7 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 			dev_err(dev, "failed to disable vpcie regulator: %d\n",
 				ret);
 	}
+	return ret;
 }
 
 static int imx6_pcie_wait_for_speed_change(struct imx6_pcie *imx6_pcie)
@@ -911,11 +912,18 @@ static int imx6_pcie_start_link(struct dw_pcie *pci)
 static int imx6_pcie_host_init(struct pcie_port *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;
 
 	imx6_pcie_assert_core_reset(imx6_pcie);
 	imx6_pcie_init_phy(imx6_pcie);
-	imx6_pcie_deassert_core_reset(imx6_pcie);
+	ret = imx6_pcie_deassert_core_reset(imx6_pcie);
+	if (ret < 0) {
+		dev_err(dev, "pcie deassert core reset failed: %d\n", ret);
+		return ret;
+	}
+
 	imx6_setup_phy_mpll(imx6_pcie);
 
 	return 0;
-- 
2.25.1

[PATCH v13 08/15] PCI: imx6: Disable i.MX6QDL clock when disabling ref clocks

[Richard Zhu]

When disabling PCIe clocks, disable i.MX6QDL ref clock too.

Link: https://lore.kernel.org/r/1655189942-12678-5-git-send-email-hongxing.zhu@nxp.com
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
---
 drivers/pci/controller/dwc/pci-imx6.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 78b839e92620..eaae144db4f3 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -586,6 +586,14 @@ static void imx6_pcie_disable_ref_clk(struct imx6_pcie *imx6_pcie)
 	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,
-- 
2.25.1

[PATCH v13 09/15] PCI: imx6: Call host init function directly in resume

[Richard Zhu]

Call imx6_pcie_host_init() instead of duplicating codes in resume.

Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index eaae144db4f3..2b42c37f1617 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -1034,9 +1034,9 @@ 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);
-- 
2.25.1

[PATCH v13 10/15] PCI: imx6: Turn off regulator when system is in suspend mode

[Richard Zhu]

The driver should undo any enables it did itself. The regulator disable
shouldn't be basing decisions on regulator_is_enabled().

Move the regulator_disable to the suspend function, turn off regulator when
the system is in suspend mode.

To keep the balance of the regulator usage counter, disable the regulator
in shutdown.

Link: https://lore.kernel.org/r/1655189942-12678-6-git-send-email-hongxing.z
hu@nxp.com
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 2b42c37f1617..f72eb609769b 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -670,8 +670,6 @@ static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_pcie)
 
 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:
@@ -702,14 +700,6 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
 		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,
@@ -722,7 +712,7 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 	struct device *dev = pci->dev;
 	int ret;
 
-	if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) {
+	if (imx6_pcie->vpcie) {
 		ret = regulator_enable(imx6_pcie->vpcie);
 		if (ret) {
 			dev_err(dev, "failed to enable vpcie regulator: %d\n",
@@ -795,7 +785,7 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 	return 0;
 
 err_clks:
-	if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
+	if (imx6_pcie->vpcie) {
 		ret = regulator_disable(imx6_pcie->vpcie);
 		if (ret)
 			dev_err(dev, "failed to disable vpcie regulator: %d\n",
@@ -1022,6 +1012,9 @@ static int imx6_pcie_suspend_noirq(struct device *dev)
 		break;
 	}
 
+	if (imx6_pcie->vpcie)
+		regulator_disable(imx6_pcie->vpcie);
+
 	return 0;
 }
 
@@ -1268,6 +1261,8 @@ static void imx6_pcie_shutdown(struct platform_device *pdev)
 
 	/* bring down link, so bootloader gets clean state in case of reboot */
 	imx6_pcie_assert_core_reset(imx6_pcie);
+	if (imx6_pcie->vpcie)
+		regulator_disable(imx6_pcie->vpcie);
 }
 
 static const struct imx6_pcie_drvdata drvdata[] = {
-- 
2.25.1

[PATCH v13 11/15] PCI: imx6: Move regulator enable out of imx6_pcie_deassert_core_reset()

[Richard Zhu]

Move regulator enable out of imx6_pcie_deassert_core_reset(), since the
regulator_enable() has nothing to do in with
imx6_pcie_deassert_core_reset().

Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 36 ++++++++++++---------------
 1 file changed, 16 insertions(+), 20 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index f72eb609769b..0b168f0d57b8 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -712,19 +712,10 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 	struct device *dev = pci->dev;
 	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;
-		}
-	}
-
 	ret = imx6_pcie_clk_enable(imx6_pcie);
 	if (ret) {
 		dev_err(dev, "unable to enable pcie clocks: %d\n", ret);
-		goto err_clks;
+		return ret;
 	}
 
 	switch (imx6_pcie->drvdata->variant) {
@@ -783,15 +774,6 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 	}
 
 	return 0;
-
-err_clks:
-	if (imx6_pcie->vpcie) {
-		ret = regulator_disable(imx6_pcie->vpcie);
-		if (ret)
-			dev_err(dev, "failed to disable vpcie regulator: %d\n",
-				ret);
-	}
-	return ret;
 }
 
 static int imx6_pcie_wait_for_speed_change(struct imx6_pcie *imx6_pcie)
@@ -916,15 +898,29 @@ static int imx6_pcie_host_init(struct pcie_port *pp)
 
 	imx6_pcie_assert_core_reset(imx6_pcie);
 	imx6_pcie_init_phy(imx6_pcie);
+	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;
+		}
+	}
+
 	ret = imx6_pcie_deassert_core_reset(imx6_pcie);
 	if (ret < 0) {
 		dev_err(dev, "pcie deassert core reset failed: %d\n", ret);
-		return ret;
+		goto err_reg_disable;
 	}
 
 	imx6_setup_phy_mpll(imx6_pcie);
 
 	return 0;
+
+err_reg_disable:
+	if (imx6_pcie->vpcie)
+		regulator_disable(imx6_pcie->vpcie);
+	return ret;
 }
 
 static const struct dw_pcie_host_ops imx6_pcie_host_ops = {
-- 
2.25.1

[PATCH v13 12/15] PCI: imx6: Mark the link down as non-fatal error

[Richard Zhu]

Let the driver probe successfully, return zero in imx6_pcie_start_link()
when PCIe link is down.

Link: https://lore.kernel.org/r/1655189942-12678-7-git-send-email-hongxing.zhu@nxp.com
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 0b168f0d57b8..e236f824c808 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -836,7 +836,9 @@ static int imx6_pcie_start_link(struct dw_pcie *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. */
@@ -872,7 +874,9 @@ 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");
 	}
@@ -886,7 +890,7 @@ static int imx6_pcie_start_link(struct dw_pcie *pci)
 		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 int imx6_pcie_host_init(struct pcie_port *pp)
-- 
2.25.1

[PATCH v13 13/15] PCI: imx6: Reduce resume time by only starting link if it was up before suspend

[Richard Zhu]

Because i.MX PCIe doesn't support hot-plug feature.  In the link down
scenario, only start the PCIe link training in resume when the link is up
before system suspend to avoid the long latency in the link training
period.

Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index e236f824c808..abce427f5d3f 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/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;
@@ -881,6 +882,7 @@ static int imx6_pcie_start_link(struct dw_pcie *pci)
 		dev_info(dev, "Link: Gen2 disabled\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;
@@ -1032,9 +1034,8 @@ static int imx6_pcie_resume_noirq(struct device *dev)
 		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;
 }
-- 
2.25.1

[PATCH v13 14/15] PCI: imx6: Do not hide phy driver callbacks and refine the error handling

[Richard Zhu]

- Move the phy_power_on() to host_init and resume functions from
  imx6_pcie_clk_enable().
- Move the phy_init() to host_init and resume functions from
  imx6_pcie_deassert_core_reset().

Refine the error handling in imx6_pcie_host_init() accordingly.

Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 35 +++++++++++++++++----------
 1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index abce427f5d3f..363bfc4742cf 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -639,14 +639,6 @@ static int imx6_pcie_clk_enable(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;
@@ -723,10 +715,6 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 	case IMX8MQ:
 		reset_control_deassert(imx6_pcie->pciephy_reset);
 		break;
-	case IMX8MM:
-		if (phy_init(imx6_pcie->phy))
-			dev_err(dev, "waiting for phy ready timeout!\n");
-		break;
 	case IMX7D:
 		reset_control_deassert(imx6_pcie->pciephy_reset);
 
@@ -762,6 +750,7 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 		usleep_range(200, 500);
 		break;
 	case IMX6Q:		/* Nothing to do */
+	case IMX8MM:
 		break;
 	}
 
@@ -904,12 +893,20 @@ static int imx6_pcie_host_init(struct pcie_port *pp)
 
 	imx6_pcie_assert_core_reset(imx6_pcie);
 	imx6_pcie_init_phy(imx6_pcie);
+	if (imx6_pcie->phy) {
+		ret = phy_power_on(imx6_pcie->phy);
+		if (ret) {
+			dev_err(dev, "pcie phy power up failed.\n");
+			return 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;
+			goto err_phy_off;
 		}
 	}
 
@@ -919,13 +916,25 @@ static int imx6_pcie_host_init(struct pcie_port *pp)
 		goto err_reg_disable;
 	}
 
+	if (imx6_pcie->phy) {
+		ret = phy_init(imx6_pcie->phy);
+		if (ret) {
+			dev_err(dev, "waiting for phy ready timeout!\n");
+			goto err_phy_init;
+		}
+	}
 	imx6_setup_phy_mpll(imx6_pcie);
 
 	return 0;
 
+err_phy_init:
+	imx6_pcie_clk_disable(imx6_pcie);
 err_reg_disable:
 	if (imx6_pcie->vpcie)
 		regulator_disable(imx6_pcie->vpcie);
+err_phy_off:
+	if (imx6_pcie->phy)
+		phy_power_off(imx6_pcie->phy);
 	return ret;
 }
 
-- 
2.25.1

[PATCH v13 15/15] PCI: imx6: Disable clocks in reverse order of enable

[Richard Zhu]

From: Bjorn Helgaas <bhelgaas@google.com>

imx6_pcie_clk_enable() enables clocks in the order:

  pcie_phy
  pcie_bus
  pcie
  imx6_pcie_enable_ref_clk

Change imx6_pcie_clk_disable() to disable them in the reverse order.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Richard Zhu <hongxing.zhu@nxp.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 363bfc4742cf..94ce77b674a3 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -655,10 +655,10 @@ static int imx6_pcie_clk_enable(struct imx6_pcie *imx6_pcie)
 
 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_phy);
 	clk_disable_unprepare(imx6_pcie->pcie_bus);
-	imx6_pcie_disable_ref_clk(imx6_pcie);
+	clk_disable_unprepare(imx6_pcie->pcie_phy);
 }
 
 static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
-- 
2.25.1

Re: [PATCH v13 10/15] PCI: imx6: Turn off regulator when system is in suspend mode

[Bjorn Helgaas]

On Fri, Jun 17, 2022 at 06:31:09PM +0800, Richard Zhu wrote:
> The driver should undo any enables it did itself. The regulator disable
> shouldn't be basing decisions on regulator_is_enabled().
> 
> Move the regulator_disable to the suspend function, turn off regulator when
> the system is in suspend mode.
> 
> To keep the balance of the regulator usage counter, disable the regulator
> in shutdown.
> 
> Link: https://lore.kernel.org/r/1655189942-12678-6-git-send-email-hongxing.z
> hu@nxp.com
> Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++------------
>  1 file changed, 7 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 2b42c37f1617..f72eb609769b 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -670,8 +670,6 @@ static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_pcie)
>  
>  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:
> @@ -702,14 +700,6 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
>  		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,
> @@ -722,7 +712,7 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
>  	struct device *dev = pci->dev;
>  	int ret;
>  
> -	if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) {
> +	if (imx6_pcie->vpcie) {
>  		ret = regulator_enable(imx6_pcie->vpcie);
>  		if (ret) {
>  			dev_err(dev, "failed to enable vpcie regulator: %d\n",
> @@ -795,7 +785,7 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
>  	return 0;
>  
>  err_clks:
> -	if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
> +	if (imx6_pcie->vpcie) {
>  		ret = regulator_disable(imx6_pcie->vpcie);
>  		if (ret)
>  			dev_err(dev, "failed to disable vpcie regulator: %d\n",
> @@ -1022,6 +1012,9 @@ static int imx6_pcie_suspend_noirq(struct device *dev)
>  		break;
>  	}
>  
> +	if (imx6_pcie->vpcie)
> +		regulator_disable(imx6_pcie->vpcie);
> +
>  	return 0;
>  }

The suspend and resume methods should be symmetric, and they should
*look* symmetric.

imx6_pcie_suspend_noirq() disables the regulator, so
imx6_pcie_resume_noirq() should enable it.

imx6_pcie_suspend_noirq() calls imx6_pcie_clk_disable() to disable
several clocks.  imx6_pcie_resume_noirq() should call
imx6_pcie_clk_enable() to enable them.

imx6_pcie_clk_enable() *is* called in the resume path, but it's buried
inside imx6_pcie_host_init() and imx6_pcie_deassert_core_reset().
That makes it hard to analyze.

We should be able to look at imx6_pcie_suspend_noirq() and
imx6_pcie_resume_noirq() and easily see that the resume path resumes
everything that was suspended in the suspend path.

Bjorn

RE: [PATCH v13 10/15] PCI: imx6: Turn off regulator when system is in suspend mode

[Hongxing Zhu]

> -----Original Message-----
> From: Bjorn Helgaas <helgaas@kernel.org>
> Sent: 2022年6月24日 6:20
> To: Hongxing Zhu <hongxing.zhu@nxp.com>
> Cc: l.stach@pengutronix.de; bhelgaas@google.com; robh+dt@kernel.org;
> broonie@kernel.org; lorenzo.pieralisi@arm.com; festevam@gmail.com;
> francesco.dolcini@toradex.com; linux-pci@vger.kernel.org;
> linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org;
> kernel@pengutronix.de; dl-linux-imx <linux-imx@nxp.com>
> Subject: Re: [PATCH v13 10/15] PCI: imx6: Turn off regulator when system is in
> suspend mode
> 
> On Fri, Jun 17, 2022 at 06:31:09PM +0800, Richard Zhu wrote:
> > The driver should undo any enables it did itself. The regulator
> > disable shouldn't be basing decisions on regulator_is_enabled().
> >
> > Move the regulator_disable to the suspend function, turn off regulator
> > when the system is in suspend mode.
> >
> > To keep the balance of the regulator usage counter, disable the
> > regulator in shutdown.
> >
> > Link:
> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore
> > .kernel.org%2Fr%2F1655189942-12678-6-git-send-email-hongxing.z&amp;d
> at
> >
> a=05%7C01%7Chongxing.zhu%40nxp.com%7C5633fa1bf3c443e203e108da55
> 667dc2%
> >
> 7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6379161959277276
> 04%7CUnkn
> >
> own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1
> haWwi
> >
> LCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=1Kbzn3XSVvt3gGPrEy%2
> BET8EZn4I
> > dwS%2BhUZ3AalZ2YZ0%3D&amp;reserved=0
> > hu@nxp.com
> > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> > ---
> >  drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++------------
> >  1 file changed, 7 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > b/drivers/pci/controller/dwc/pci-imx6.c
> > index 2b42c37f1617..f72eb609769b 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -670,8 +670,6 @@ static void imx6_pcie_clk_disable(struct imx6_pcie
> > *imx6_pcie)
> >
> >  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:
> > @@ -702,14 +700,6 @@ static void imx6_pcie_assert_core_reset(struct
> imx6_pcie *imx6_pcie)
> >  		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,
> > @@ -722,7 +712,7 @@ static int imx6_pcie_deassert_core_reset(struct
> imx6_pcie *imx6_pcie)
> >  	struct device *dev = pci->dev;
> >  	int ret;
> >
> > -	if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) {
> > +	if (imx6_pcie->vpcie) {
> >  		ret = regulator_enable(imx6_pcie->vpcie);
> >  		if (ret) {
> >  			dev_err(dev, "failed to enable vpcie regulator: %d\n", @@
> -795,7
> > +785,7 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie
> *imx6_pcie)
> >  	return 0;
> >
> >  err_clks:
> > -	if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
> > +	if (imx6_pcie->vpcie) {
> >  		ret = regulator_disable(imx6_pcie->vpcie);
> >  		if (ret)
> >  			dev_err(dev, "failed to disable vpcie regulator: %d\n", @@
> -1022,6
> > +1012,9 @@ static int imx6_pcie_suspend_noirq(struct device *dev)
> >  		break;
> >  	}
> >
> > +	if (imx6_pcie->vpcie)
> > +		regulator_disable(imx6_pcie->vpcie);
> > +
> >  	return 0;
> >  }
> 
> The suspend and resume methods should be symmetric, and they should
> *look* symmetric.
> 
> imx6_pcie_suspend_noirq() disables the regulator, so
> imx6_pcie_resume_noirq() should enable it.
> 
> imx6_pcie_suspend_noirq() calls imx6_pcie_clk_disable() to disable several
> clocks.  imx6_pcie_resume_noirq() should call
> imx6_pcie_clk_enable() to enable them.
> 
> imx6_pcie_clk_enable() *is* called in the resume path, but it's buried inside
> imx6_pcie_host_init() and imx6_pcie_deassert_core_reset().
> That makes it hard to analyze.
> 
> We should be able to look at imx6_pcie_suspend_noirq() and
> imx6_pcie_resume_noirq() and easily see that the resume path resumes
> everything that was suspended in the suspend path.
Hi Bjorn:
Thanks for your kindly help to review it.
Yes, it is. It's better to keep suspend/resume symmetric as much as possible.
In resume, the host_init is invoked, clocks, regulators and so on would be
initialized properly. 
Unfortunately, there is no according host_exit() that can be called to do the
reversed clocks, regulators disable operations in the suspend.
So, the clocks and regulator disable are explicitly invoked in suspend callback.

How about to do the incremental updates if the .host_exit can be added later?

Best Regards
Richard Zhu
> 
> Bjorn

Re: [PATCH v13 10/15] PCI: imx6: Turn off regulator when system is in suspend mode

[Bjorn Helgaas]

On Fri, Jun 24, 2022 at 05:05:00AM +0000, Hongxing Zhu wrote:
> > -----Original Message-----
> > From: Bjorn Helgaas <helgaas@kernel.org>
> > Sent: 2022年6月24日 6:20
> > To: Hongxing Zhu <hongxing.zhu@nxp.com>
> > Cc: l.stach@pengutronix.de; bhelgaas@google.com; robh+dt@kernel.org;
> > broonie@kernel.org; lorenzo.pieralisi@arm.com; festevam@gmail.com;
> > francesco.dolcini@toradex.com; linux-pci@vger.kernel.org;
> > linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org;
> > kernel@pengutronix.de; dl-linux-imx <linux-imx@nxp.com>
> > Subject: Re: [PATCH v13 10/15] PCI: imx6: Turn off regulator when system is in
> > suspend mode
> > 
> > On Fri, Jun 17, 2022 at 06:31:09PM +0800, Richard Zhu wrote:
> > > The driver should undo any enables it did itself. The regulator
> > > disable shouldn't be basing decisions on regulator_is_enabled().
> > >
> > > Move the regulator_disable to the suspend function, turn off regulator
> > > when the system is in suspend mode.
> > >
> > > To keep the balance of the regulator usage counter, disable the
> > > regulator in shutdown.
> > >
> > > Link:
> > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore
> > > .kernel.org%2Fr%2F1655189942-12678-6-git-send-email-hongxing.z&amp;d
> > at
> > >
> > a=05%7C01%7Chongxing.zhu%40nxp.com%7C5633fa1bf3c443e203e108da55
> > 667dc2%
> > >
> > 7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6379161959277276
> > 04%7CUnkn
> > >
> > own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1
> > haWwi
> > >
> > LCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=1Kbzn3XSVvt3gGPrEy%2
> > BET8EZn4I
> > > dwS%2BhUZ3AalZ2YZ0%3D&amp;reserved=0
> > > hu@nxp.com
> > > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> > > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> > > ---
> > >  drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++------------
> > >  1 file changed, 7 insertions(+), 12 deletions(-)
> > >
> > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > > b/drivers/pci/controller/dwc/pci-imx6.c
> > > index 2b42c37f1617..f72eb609769b 100644
> > > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > > @@ -670,8 +670,6 @@ static void imx6_pcie_clk_disable(struct imx6_pcie
> > > *imx6_pcie)
> > >
> > >  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:
> > > @@ -702,14 +700,6 @@ static void imx6_pcie_assert_core_reset(struct
> > imx6_pcie *imx6_pcie)
> > >  		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,
> > > @@ -722,7 +712,7 @@ static int imx6_pcie_deassert_core_reset(struct
> > imx6_pcie *imx6_pcie)
> > >  	struct device *dev = pci->dev;
> > >  	int ret;
> > >
> > > -	if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) {
> > > +	if (imx6_pcie->vpcie) {
> > >  		ret = regulator_enable(imx6_pcie->vpcie);
> > >  		if (ret) {
> > >  			dev_err(dev, "failed to enable vpcie regulator: %d\n", @@
> > -795,7
> > > +785,7 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie
> > *imx6_pcie)
> > >  	return 0;
> > >
> > >  err_clks:
> > > -	if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
> > > +	if (imx6_pcie->vpcie) {
> > >  		ret = regulator_disable(imx6_pcie->vpcie);
> > >  		if (ret)
> > >  			dev_err(dev, "failed to disable vpcie regulator: %d\n", @@
> > -1022,6
> > > +1012,9 @@ static int imx6_pcie_suspend_noirq(struct device *dev)
> > >  		break;
> > >  	}
> > >
> > > +	if (imx6_pcie->vpcie)
> > > +		regulator_disable(imx6_pcie->vpcie);
> > > +
> > >  	return 0;
> > >  }
> > 
> > The suspend and resume methods should be symmetric, and they should
> > *look* symmetric.
> > 
> > imx6_pcie_suspend_noirq() disables the regulator, so
> > imx6_pcie_resume_noirq() should enable it.
> > 
> > imx6_pcie_suspend_noirq() calls imx6_pcie_clk_disable() to disable
> > several clocks.  imx6_pcie_resume_noirq() should call
> > imx6_pcie_clk_enable() to enable them.
> > 
> > imx6_pcie_clk_enable() *is* called in the resume path, but it's
> > buried inside imx6_pcie_host_init() and
> > imx6_pcie_deassert_core_reset().  That makes it hard to analyze.
> > 
> > We should be able to look at imx6_pcie_suspend_noirq() and
> > imx6_pcie_resume_noirq() and easily see that the resume path
> > resumes everything that was suspended in the suspend path.
>
> Yes, it is. It's better to keep suspend/resume symmetric as much as
> possible.  In resume, the host_init is invoked, clocks, regulators
> and so on would be initialized properly. 
>
> Unfortunately, there is no according host_exit() that can be called
> to do the reversed clocks, regulators disable operations in the
> suspend.  So, the clocks and regulator disable are explicitly
> invoked in suspend callback.
> 
> How about to do the incremental updates if the .host_exit can be
> added later?

This doesn't seem very convincing because everything here is in the
imx6 domain.  The only DWC core thing here is the dw_pcie_setup_rc() 
called in imx6_pcie_resume_noirq(), and it doesn't call back to any
imx6 code.

So you should be able to make an imx6_pcie_host_exit() or whatever
that corresponds to imx6_pcie_host_init().

RE: [PATCH v13 10/15] PCI: imx6: Turn off regulator when system is in suspend mode

[Hongxing Zhu]

> -----Original Message-----
> From: Bjorn Helgaas <helgaas@kernel.org>
> Sent: 2022年6月28日 3:52
> To: Hongxing Zhu <hongxing.zhu@nxp.com>
> Cc: l.stach@pengutronix.de; bhelgaas@google.com; robh+dt@kernel.org;
> broonie@kernel.org; lorenzo.pieralisi@arm.com; festevam@gmail.com;
> francesco.dolcini@toradex.com; linux-pci@vger.kernel.org;
> linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org;
> kernel@pengutronix.de; dl-linux-imx <linux-imx@nxp.com>
> Subject: Re: [PATCH v13 10/15] PCI: imx6: Turn off regulator when system is in
> suspend mode
> 
> On Fri, Jun 24, 2022 at 05:05:00AM +0000, Hongxing Zhu wrote:
> > > -----Original Message-----
> > > From: Bjorn Helgaas <helgaas@kernel.org>
> > > Sent: 2022年6月24日 6:20
> > > To: Hongxing Zhu <hongxing.zhu@nxp.com>
> > > Cc: l.stach@pengutronix.de; bhelgaas@google.com; robh+dt@kernel.org;
> > > broonie@kernel.org; lorenzo.pieralisi@arm.com; festevam@gmail.com;
> > > francesco.dolcini@toradex.com; linux-pci@vger.kernel.org;
> > > linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org;
> > > kernel@pengutronix.de; dl-linux-imx <linux-imx@nxp.com>
> > > Subject: Re: [PATCH v13 10/15] PCI: imx6: Turn off regulator when
> > > system is in suspend mode
> > >
> > > On Fri, Jun 17, 2022 at 06:31:09PM +0800, Richard Zhu wrote:
> > > > The driver should undo any enables it did itself. The regulator
> > > > disable shouldn't be basing decisions on regulator_is_enabled().
> > > >
> > > > Move the regulator_disable to the suspend function, turn off
> > > > regulator when the system is in suspend mode.
> > > >
> > > > To keep the balance of the regulator usage counter, disable the
> > > > regulator in shutdown.
> > > >
> > > > Link:
> > > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2F
> > > > lore
> > > > .kernel.org%2Fr%2F1655189942-12678-6-git-send-email-hongxing.z&am
> p
> > > > ;d
> > > at
> > > >
> > >
> a=05%7C01%7Chongxing.zhu%40nxp.com%7C5633fa1bf3c443e203e108da55
> > > 667dc2%
> > > >
> > >
> 7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6379161959277276
> > > 04%7CUnkn
> > > >
> > >
> own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1
> > > haWwi
> > > >
> > >
> LCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=1Kbzn3XSVvt3gGPrEy%2
> > > BET8EZn4I
> > > > dwS%2BhUZ3AalZ2YZ0%3D&amp;reserved=0
> > > > hu@nxp.com
> > > > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> > > > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> > > > ---
> > > >  drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++------------
> > > >  1 file changed, 7 insertions(+), 12 deletions(-)
> > > >
> > > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > > > b/drivers/pci/controller/dwc/pci-imx6.c
> > > > index 2b42c37f1617..f72eb609769b 100644
> > > > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > > > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > > > @@ -670,8 +670,6 @@ static void imx6_pcie_clk_disable(struct
> > > > imx6_pcie
> > > > *imx6_pcie)
> > > >
> > > >  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:
> > > > @@ -702,14 +700,6 @@ static void
> > > > imx6_pcie_assert_core_reset(struct
> > > imx6_pcie *imx6_pcie)
> > > >  		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,
> > > > @@ -722,7 +712,7 @@ static int
> > > > imx6_pcie_deassert_core_reset(struct
> > > imx6_pcie *imx6_pcie)
> > > >  	struct device *dev = pci->dev;
> > > >  	int ret;
> > > >
> > > > -	if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) {
> > > > +	if (imx6_pcie->vpcie) {
> > > >  		ret = regulator_enable(imx6_pcie->vpcie);
> > > >  		if (ret) {
> > > >  			dev_err(dev, "failed to enable vpcie regulator: %d\n", @@
> > > -795,7
> > > > +785,7 @@ static int imx6_pcie_deassert_core_reset(struct
> > > > +imx6_pcie
> > > *imx6_pcie)
> > > >  	return 0;
> > > >
> > > >  err_clks:
> > > > -	if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0)
> {
> > > > +	if (imx6_pcie->vpcie) {
> > > >  		ret = regulator_disable(imx6_pcie->vpcie);
> > > >  		if (ret)
> > > >  			dev_err(dev, "failed to disable vpcie regulator: %d\n", @@
> > > -1022,6
> > > > +1012,9 @@ static int imx6_pcie_suspend_noirq(struct device *dev)
> > > >  		break;
> > > >  	}
> > > >
> > > > +	if (imx6_pcie->vpcie)
> > > > +		regulator_disable(imx6_pcie->vpcie);
> > > > +
> > > >  	return 0;
> > > >  }
> > >
> > > The suspend and resume methods should be symmetric, and they should
> > > *look* symmetric.
> > >
> > > imx6_pcie_suspend_noirq() disables the regulator, so
> > > imx6_pcie_resume_noirq() should enable it.
> > >
> > > imx6_pcie_suspend_noirq() calls imx6_pcie_clk_disable() to disable
> > > several clocks.  imx6_pcie_resume_noirq() should call
> > > imx6_pcie_clk_enable() to enable them.
> > >
> > > imx6_pcie_clk_enable() *is* called in the resume path, but it's
> > > buried inside imx6_pcie_host_init() and
> > > imx6_pcie_deassert_core_reset().  That makes it hard to analyze.
> > >
> > > We should be able to look at imx6_pcie_suspend_noirq() and
> > > imx6_pcie_resume_noirq() and easily see that the resume path resumes
> > > everything that was suspended in the suspend path.
> >
> > Yes, it is. It's better to keep suspend/resume symmetric as much as
> > possible.  In resume, the host_init is invoked, clocks, regulators and
> > so on would be initialized properly.
> >
> > Unfortunately, there is no according host_exit() that can be called to
> > do the reversed clocks, regulators disable operations in the suspend.
> > So, the clocks and regulator disable are explicitly invoked in suspend
> > callback.
> >
> > How about to do the incremental updates if the .host_exit can be added
> > later?
> 
> This doesn't seem very convincing because everything here is in the
> imx6 domain.  The only DWC core thing here is the dw_pcie_setup_rc() called
> in imx6_pcie_resume_noirq(), and it doesn't call back to any
> imx6 code.
> 
> So you should be able to make an imx6_pcie_host_exit() or whatever that
> corresponds to imx6_pcie_host_init().
Hi Bjorn:
Thanks for your kindly help to review it. That's reasonable.

So, to make it symmetric with imx6_pcie_host_init() and imx6_pcie_start_link().
The according local functions imx6_pcie_host_exit() and imx6_pcie_stop_link()
would be created.

BTW, to be symmetric with imx6_pcie_host_init(), the parameter of
imx6_pcie_host_exit() is same to the parameter of imx6_pcie_host_init().
So do imx6_pcie_stop_link() and imx6_pcie_start_link().
Are you satisfied with the following functions?

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 void imx6_pcie_host_exit(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_clk_disable(imx6_pcie);
        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);
        }

        if (imx6_pcie->vpcie)
                regulator_disable(imx6_pcie->vpcie);
}

Best Regards
Richard Zhu

Re: [PATCH v13 10/15] PCI: imx6: Turn off regulator when system is in suspend mode

[Bjorn Helgaas]

On Tue, Jun 28, 2022 at 03:48:01AM +0000, Hongxing Zhu wrote:
> > -----Original Message-----
> > From: Bjorn Helgaas <helgaas@kernel.org>
> > Sent: 2022年6月28日 3:52
> > To: Hongxing Zhu <hongxing.zhu@nxp.com>
> > Cc: l.stach@pengutronix.de; bhelgaas@google.com; robh+dt@kernel.org;
> > broonie@kernel.org; lorenzo.pieralisi@arm.com; festevam@gmail.com;
> > francesco.dolcini@toradex.com; linux-pci@vger.kernel.org;
> > linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org;
> > kernel@pengutronix.de; dl-linux-imx <linux-imx@nxp.com>
> > Subject: Re: [PATCH v13 10/15] PCI: imx6: Turn off regulator when system is in
> > suspend mode
> > 
> > On Fri, Jun 24, 2022 at 05:05:00AM +0000, Hongxing Zhu wrote:
> > > > -----Original Message-----
> > > > From: Bjorn Helgaas <helgaas@kernel.org>
> > > > Sent: 2022年6月24日 6:20
> > > > To: Hongxing Zhu <hongxing.zhu@nxp.com>
> > > > Cc: l.stach@pengutronix.de; bhelgaas@google.com; robh+dt@kernel.org;
> > > > broonie@kernel.org; lorenzo.pieralisi@arm.com; festevam@gmail.com;
> > > > francesco.dolcini@toradex.com; linux-pci@vger.kernel.org;
> > > > linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org;
> > > > kernel@pengutronix.de; dl-linux-imx <linux-imx@nxp.com>
> > > > Subject: Re: [PATCH v13 10/15] PCI: imx6: Turn off regulator when
> > > > system is in suspend mode
> > > >
> > > > On Fri, Jun 17, 2022 at 06:31:09PM +0800, Richard Zhu wrote:
> > > > > The driver should undo any enables it did itself. The regulator
> > > > > disable shouldn't be basing decisions on regulator_is_enabled().
> > > > >
> > > > > Move the regulator_disable to the suspend function, turn off
> > > > > regulator when the system is in suspend mode.
> > > > >
> > > > > To keep the balance of the regulator usage counter, disable the
> > > > > regulator in shutdown.
> > > > >
> > > > > Link:
> > > > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2F
> > > > > lore
> > > > > .kernel.org%2Fr%2F1655189942-12678-6-git-send-email-hongxing.z&am
> > p
> > > > > ;d
> > > > at
> > > > >
> > > >
> > a=05%7C01%7Chongxing.zhu%40nxp.com%7C5633fa1bf3c443e203e108da55
> > > > 667dc2%
> > > > >
> > > >
> > 7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6379161959277276
> > > > 04%7CUnkn
> > > > >
> > > >
> > own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1
> > > > haWwi
> > > > >
> > > >
> > LCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=1Kbzn3XSVvt3gGPrEy%2
> > > > BET8EZn4I
> > > > > dwS%2BhUZ3AalZ2YZ0%3D&amp;reserved=0
> > > > > hu@nxp.com
> > > > > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> > > > > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> > > > > ---
> > > > >  drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++------------
> > > > >  1 file changed, 7 insertions(+), 12 deletions(-)
> > > > >
> > > > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > > > > b/drivers/pci/controller/dwc/pci-imx6.c
> > > > > index 2b42c37f1617..f72eb609769b 100644
> > > > > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > > > > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > > > > @@ -670,8 +670,6 @@ static void imx6_pcie_clk_disable(struct
> > > > > imx6_pcie
> > > > > *imx6_pcie)
> > > > >
> > > > >  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:
> > > > > @@ -702,14 +700,6 @@ static void
> > > > > imx6_pcie_assert_core_reset(struct
> > > > imx6_pcie *imx6_pcie)
> > > > >  		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,
> > > > > @@ -722,7 +712,7 @@ static int
> > > > > imx6_pcie_deassert_core_reset(struct
> > > > imx6_pcie *imx6_pcie)
> > > > >  	struct device *dev = pci->dev;
> > > > >  	int ret;
> > > > >
> > > > > -	if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) {
> > > > > +	if (imx6_pcie->vpcie) {
> > > > >  		ret = regulator_enable(imx6_pcie->vpcie);
> > > > >  		if (ret) {
> > > > >  			dev_err(dev, "failed to enable vpcie regulator: %d\n", @@
> > > > -795,7
> > > > > +785,7 @@ static int imx6_pcie_deassert_core_reset(struct
> > > > > +imx6_pcie
> > > > *imx6_pcie)
> > > > >  	return 0;
> > > > >
> > > > >  err_clks:
> > > > > -	if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0)
> > {
> > > > > +	if (imx6_pcie->vpcie) {
> > > > >  		ret = regulator_disable(imx6_pcie->vpcie);
> > > > >  		if (ret)
> > > > >  			dev_err(dev, "failed to disable vpcie regulator: %d\n", @@
> > > > -1022,6
> > > > > +1012,9 @@ static int imx6_pcie_suspend_noirq(struct device *dev)
> > > > >  		break;
> > > > >  	}
> > > > >
> > > > > +	if (imx6_pcie->vpcie)
> > > > > +		regulator_disable(imx6_pcie->vpcie);
> > > > > +
> > > > >  	return 0;
> > > > >  }
> > > >
> > > > The suspend and resume methods should be symmetric, and they should
> > > > *look* symmetric.
> > > >
> > > > imx6_pcie_suspend_noirq() disables the regulator, so
> > > > imx6_pcie_resume_noirq() should enable it.
> > > >
> > > > imx6_pcie_suspend_noirq() calls imx6_pcie_clk_disable() to disable
> > > > several clocks.  imx6_pcie_resume_noirq() should call
> > > > imx6_pcie_clk_enable() to enable them.
> > > >
> > > > imx6_pcie_clk_enable() *is* called in the resume path, but it's
> > > > buried inside imx6_pcie_host_init() and
> > > > imx6_pcie_deassert_core_reset().  That makes it hard to analyze.
> > > >
> > > > We should be able to look at imx6_pcie_suspend_noirq() and
> > > > imx6_pcie_resume_noirq() and easily see that the resume path resumes
> > > > everything that was suspended in the suspend path.
> > >
> > > Yes, it is. It's better to keep suspend/resume symmetric as much as
> > > possible.  In resume, the host_init is invoked, clocks, regulators and
> > > so on would be initialized properly.
> > >
> > > Unfortunately, there is no according host_exit() that can be called to
> > > do the reversed clocks, regulators disable operations in the suspend.
> > > So, the clocks and regulator disable are explicitly invoked in suspend
> > > callback.
> > >
> > > How about to do the incremental updates if the .host_exit can be added
> > > later?
> > 
> > This doesn't seem very convincing because everything here is in the
> > imx6 domain.  The only DWC core thing here is the dw_pcie_setup_rc() called
> > in imx6_pcie_resume_noirq(), and it doesn't call back to any
> > imx6 code.
> > 
> > So you should be able to make an imx6_pcie_host_exit() or whatever that
> > corresponds to imx6_pcie_host_init().
>
> Thanks for your kindly help to review it. That's reasonable.
> 
> So, to make it symmetric with imx6_pcie_host_init() and
> imx6_pcie_start_link().  The according local functions
> imx6_pcie_host_exit() and imx6_pcie_stop_link() would be created.
> 
> BTW, to be symmetric with imx6_pcie_host_init(), the parameter of
> imx6_pcie_host_exit() is same to the parameter of
> imx6_pcie_host_init().  So do imx6_pcie_stop_link() and
> imx6_pcie_start_link().  Are you satisfied with the following
> functions?
> 
> 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 void imx6_pcie_host_exit(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_clk_disable(imx6_pcie);
>         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);
>         }
> 
>         if (imx6_pcie->vpcie)
>                 regulator_disable(imx6_pcie->vpcie);
> }

After the current series, imx6_pcie_host_init() looks like:

  imx6_pcie_host_init
    phy_power_on
    regulator_enable
    imx6_pcie_deassert_core_reset
      imx6_pcie_clk_enable
    phy_init

and you propose:

  imx6_pcie_host_exit
    imx6_pcie_clk_disable
    phy_power_off
    phy_exit
    regulator_disable

Generally they should do things in the reverse order.

imx6_pcie_host_init() does phy_power_on(), regulator_enable(),
imx6_pcie_clk_enable().

imx6_pcie_host_exit() should do imx6_pcie_clk_disable(),
regulator_disable(), phy_power_off().

(It looks like imx6_pcie_host_init() calls phy_power_on() and
phy_init() in the wrong order [1].)

IMO the imx6_pcie_clk_enable() should not be hidden inside
imx6_pcie_deassert_core_reset().

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/phy/phy-core.c?id=v5.19-rc1#n233

RE: [PATCH v13 10/15] PCI: imx6: Turn off regulator when system is in suspend mode

[Hongxing Zhu]

> -----Original Message-----
> From: Bjorn Helgaas <helgaas@kernel.org>
> Sent: 2022年6月28日 23:51
> To: Hongxing Zhu <hongxing.zhu@nxp.com>
> Cc: l.stach@pengutronix.de; bhelgaas@google.com; robh+dt@kernel.org;
> broonie@kernel.org; lorenzo.pieralisi@arm.com; festevam@gmail.com;
> francesco.dolcini@toradex.com; linux-pci@vger.kernel.org;
> linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org;
> kernel@pengutronix.de; dl-linux-imx <linux-imx@nxp.com>
> Subject: Re: [PATCH v13 10/15] PCI: imx6: Turn off regulator when system is in
> suspend mode
> 
> On Tue, Jun 28, 2022 at 03:48:01AM +0000, Hongxing Zhu wrote:
> > > -----Original Message-----
> > > From: Bjorn Helgaas <helgaas@kernel.org>
> > > Sent: 2022年6月28日 3:52
> > > To: Hongxing Zhu <hongxing.zhu@nxp.com>
> > > Cc: l.stach@pengutronix.de; bhelgaas@google.com; robh+dt@kernel.org;
> > > broonie@kernel.org; lorenzo.pieralisi@arm.com; festevam@gmail.com;
> > > francesco.dolcini@toradex.com; linux-pci@vger.kernel.org;
> > > linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org;
> > > kernel@pengutronix.de; dl-linux-imx <linux-imx@nxp.com>
> > > Subject: Re: [PATCH v13 10/15] PCI: imx6: Turn off regulator when
> > > system is in suspend mode
> > >
> > > On Fri, Jun 24, 2022 at 05:05:00AM +0000, Hongxing Zhu wrote:
> > > > > -----Original Message-----
> > > > > From: Bjorn Helgaas <helgaas@kernel.org>
> > > > > Sent: 2022年6月24日 6:20
> > > > > To: Hongxing Zhu <hongxing.zhu@nxp.com>
> > > > > Cc: l.stach@pengutronix.de; bhelgaas@google.com;
> > > > > robh+dt@kernel.org; broonie@kernel.org;
> > > > > lorenzo.pieralisi@arm.com; festevam@gmail.com;
> > > > > francesco.dolcini@toradex.com; linux-pci@vger.kernel.org;
> > > > > linux-arm-kernel@lists.infradead.org;
> > > > > linux-kernel@vger.kernel.org; kernel@pengutronix.de;
> > > > > dl-linux-imx <linux-imx@nxp.com>
> > > > > Subject: Re: [PATCH v13 10/15] PCI: imx6: Turn off regulator
> > > > > when system is in suspend mode
> > > > >
> > > > > On Fri, Jun 17, 2022 at 06:31:09PM +0800, Richard Zhu wrote:
> > > > > > The driver should undo any enables it did itself. The
> > > > > > regulator disable shouldn't be basing decisions on
> regulator_is_enabled().
> > > > > >
> > > > > > Move the regulator_disable to the suspend function, turn off
> > > > > > regulator when the system is in suspend mode.
> > > > > >
> > > > > > To keep the balance of the regulator usage counter, disable
> > > > > > the regulator in shutdown.
> > > > > >
> > > > > > Link:
> > > > > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2
> > > > > > F%2F
> > > > > > lore
> > > > > > .kernel.org%2Fr%2F1655189942-12678-6-git-send-email-hongxing.z
> > > > > > &am
> > > p
> > > > > > ;d
> > > > > at
> > > > > >
> > > > >
> > >
> a=05%7C01%7Chongxing.zhu%40nxp.com%7C5633fa1bf3c443e203e108da55
> > > > > 667dc2%
> > > > > >
> > > > >
> > >
> 7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6379161959277276
> > > > > 04%7CUnkn
> > > > > >
> > > > >
> > >
> own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1
> > > > > haWwi
> > > > > >
> > > > >
> > >
> LCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=1Kbzn3XSVvt3gGPrEy%2
> > > > > BET8EZn4I
> > > > > > dwS%2BhUZ3AalZ2YZ0%3D&amp;reserved=0
> > > > > > hu@nxp.com
> > > > > > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> > > > > > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> > > > > > ---
> > > > > >  drivers/pci/controller/dwc/pci-imx6.c | 19
> > > > > > +++++++------------
> > > > > >  1 file changed, 7 insertions(+), 12 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > > > > > b/drivers/pci/controller/dwc/pci-imx6.c
> > > > > > index 2b42c37f1617..f72eb609769b 100644
> > > > > > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > > > > > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > > > > > @@ -670,8 +670,6 @@ static void imx6_pcie_clk_disable(struct
> > > > > > imx6_pcie
> > > > > > *imx6_pcie)
> > > > > >
> > > > > >  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:
> > > > > > @@ -702,14 +700,6 @@ static void
> > > > > > imx6_pcie_assert_core_reset(struct
> > > > > imx6_pcie *imx6_pcie)
> > > > > >  		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,
> > > > > > @@ -722,7 +712,7 @@ static int
> > > > > > imx6_pcie_deassert_core_reset(struct
> > > > > imx6_pcie *imx6_pcie)
> > > > > >  	struct device *dev = pci->dev;
> > > > > >  	int ret;
> > > > > >
> > > > > > -	if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) {
> > > > > > +	if (imx6_pcie->vpcie) {
> > > > > >  		ret = regulator_enable(imx6_pcie->vpcie);
> > > > > >  		if (ret) {
> > > > > >  			dev_err(dev, "failed to enable vpcie regulator: %d\n",
> @@
> > > > > -795,7
> > > > > > +785,7 @@ static int imx6_pcie_deassert_core_reset(struct
> > > > > > +imx6_pcie
> > > > > *imx6_pcie)
> > > > > >  	return 0;
> > > > > >
> > > > > >  err_clks:
> > > > > > -	if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0)
> > > {
> > > > > > +	if (imx6_pcie->vpcie) {
> > > > > >  		ret = regulator_disable(imx6_pcie->vpcie);
> > > > > >  		if (ret)
> > > > > >  			dev_err(dev, "failed to disable vpcie regulator: %d\n",
> @@
> > > > > -1022,6
> > > > > > +1012,9 @@ static int imx6_pcie_suspend_noirq(struct device
> > > > > > +*dev)
> > > > > >  		break;
> > > > > >  	}
> > > > > >
> > > > > > +	if (imx6_pcie->vpcie)
> > > > > > +		regulator_disable(imx6_pcie->vpcie);
> > > > > > +
> > > > > >  	return 0;
> > > > > >  }
> > > > >
> > > > > The suspend and resume methods should be symmetric, and they
> > > > > should
> > > > > *look* symmetric.
> > > > >
> > > > > imx6_pcie_suspend_noirq() disables the regulator, so
> > > > > imx6_pcie_resume_noirq() should enable it.
> > > > >
> > > > > imx6_pcie_suspend_noirq() calls imx6_pcie_clk_disable() to
> > > > > disable several clocks.  imx6_pcie_resume_noirq() should call
> > > > > imx6_pcie_clk_enable() to enable them.
> > > > >
> > > > > imx6_pcie_clk_enable() *is* called in the resume path, but it's
> > > > > buried inside imx6_pcie_host_init() and
> > > > > imx6_pcie_deassert_core_reset().  That makes it hard to analyze.
> > > > >
> > > > > We should be able to look at imx6_pcie_suspend_noirq() and
> > > > > imx6_pcie_resume_noirq() and easily see that the resume path
> > > > > resumes everything that was suspended in the suspend path.
> > > >
> > > > Yes, it is. It's better to keep suspend/resume symmetric as much
> > > > as possible.  In resume, the host_init is invoked, clocks,
> > > > regulators and so on would be initialized properly.
> > > >
> > > > Unfortunately, there is no according host_exit() that can be
> > > > called to do the reversed clocks, regulators disable operations in the
> suspend.
> > > > So, the clocks and regulator disable are explicitly invoked in
> > > > suspend callback.
> > > >
> > > > How about to do the incremental updates if the .host_exit can be
> > > > added later?
> > >
> > > This doesn't seem very convincing because everything here is in the
> > > imx6 domain.  The only DWC core thing here is the dw_pcie_setup_rc()
> > > called in imx6_pcie_resume_noirq(), and it doesn't call back to any
> > > imx6 code.
> > >
> > > So you should be able to make an imx6_pcie_host_exit() or whatever
> > > that corresponds to imx6_pcie_host_init().
> >
> > Thanks for your kindly help to review it. That's reasonable.
> >
> > So, to make it symmetric with imx6_pcie_host_init() and
> > imx6_pcie_start_link().  The according local functions
> > imx6_pcie_host_exit() and imx6_pcie_stop_link() would be created.
> >
> > BTW, to be symmetric with imx6_pcie_host_init(), the parameter of
> > imx6_pcie_host_exit() is same to the parameter of
> > imx6_pcie_host_init().  So do imx6_pcie_stop_link() and
> > imx6_pcie_start_link().  Are you satisfied with the following
> > functions?
> >
> > 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 void imx6_pcie_host_exit(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_clk_disable(imx6_pcie);
> >         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);
> >         }
> >
> >         if (imx6_pcie->vpcie)
> >                 regulator_disable(imx6_pcie->vpcie);
> > }
> 
> After the current series, imx6_pcie_host_init() looks like:
> 
>   imx6_pcie_host_init
>     phy_power_on
>     regulator_enable
>     imx6_pcie_deassert_core_reset
>       imx6_pcie_clk_enable
>     phy_init
> 
> and you propose:
> 
>   imx6_pcie_host_exit
>     imx6_pcie_clk_disable
>     phy_power_off
>     phy_exit
>     regulator_disable
> 
> Generally they should do things in the reverse order.
> 
Hi Bjorn:
Thanks a lot for your review.

> imx6_pcie_host_init() does phy_power_on(), regulator_enable(),
> imx6_pcie_clk_enable().
> 
> imx6_pcie_host_exit() should do imx6_pcie_clk_disable(), regulator_disable(),
> phy_power_off().
> 
> (It looks like imx6_pcie_host_init() calls phy_power_on() and
> phy_init() in the wrong order [1].)
Yes, it is . I notice the warning too in my local tests. I made a mistake that
I assumed the PHY should be powered on firstly, then be initialized.
Since it is bug fix, how about to issue another fix commit after this series?

> 
> IMO the imx6_pcie_clk_enable() should not be hidden inside
> imx6_pcie_deassert_core_reset().
Okay, would move the imx6_pcie_clk_enable() from imx6_pcie_deassert_core_reset()
 to imx6_pcie_host_init().
Since the 6/15 of v13 has already Lucas' reviewed-by tag.
Can I combine these changes with the creation of the imx6_pcie_host_exit() and
 imx6_pcie_host_stop_link() into one patch?

> 
> [1]
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kern
> el.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git%2Ftr
> ee%2Fdrivers%2Fphy%2Fphy-core.c%3Fid%3Dv5.19-rc1%23n233&amp;data=
> 05%7C01%7Chongxing.zhu%40nxp.com%7C0e7ce8e53ee0478aabd508da591
> e06f7%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6379202827
> 66167735%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoi
> V2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdat
> a=BQQnn1ju47AGwfQW48%2Ba%2BnlLszha8P0QAynr4G3qeLM%3D&amp;res
> erved=0
Thanks a lot for your kindly reminder.

Best Regards
Richard