Merge branch 'pci/controller/dwc-imx6'

- Add DT binding and driver support for an optional external refclock in
  addition to the refclock from the internal PLL (Richard Zhu)

- Apply i.MX95 ERR051586 erratum workaround (release CLKREQ# so endpoint
  can assert it when required) during resume (Richard Zhu)

- Enable i.MX95 REFCLK by overriding CLKREQ# so it's driven by default
  (Richard Zhu)

- Clear CLKREQ# override if link is up and DT says 'supports-clkreq' so
  endpoints can use CLKREQ# to exit the L1.2 state (Richard Zhu)

* pci/controller/dwc-imx6:
  PCI: imx6: Clear CLKREQ# override if 'supports-clkreq' DT property is available
  PCI: imx6: Add CLKREQ# override to enable REFCLK for i.MX95 PCIe
  PCI: dwc: Invoke post_init in dw_pcie_resume_noirq()
  PCI: imx6: Add external reference clock input mode support
  dt-bindings: PCI: pci-imx6: Add external reference clock input
  dt-bindings: PCI: dwc: Add external reference clock input

Author: bjorn-helgaas

Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.yaml

@@ -44,7 +44,7 @@ properties:
 
   clock-names:
     minItems: 3
-    maxItems: 5
+    maxItems: 6
 
   interrupts:
     minItems: 1
@@ -212,14 +212,17 @@ allOf:
     then:
       properties:
         clocks:
-          maxItems: 5
+          minItems: 5
+          maxItems: 6
         clock-names:
+          minItems: 5
           items:
             - const: pcie
             - const: pcie_bus
             - const: pcie_phy
             - const: pcie_aux
             - const: ref
+            - const: extref  # Optional
 
 unevaluatedProperties: false
 

Documentation/devicetree/bindings/pci/snps,dw-pcie-common.yaml

@@ -105,6 +105,12 @@ properties:
             define it with this name (for instance pipe, core and aux can
             be connected to a single source of the periodic signal).
           const: ref
+        - description:
+            Some dwc wrappers (like i.MX95 PCIes) have two reference clock
+            inputs, one from an internal PLL, the other from an off-chip crystal
+            oscillator. If present, 'extref' refers to a reference clock from
+            an external oscillator.
+          const: extref
         - description:
             Clock for the PHY registers interface. Originally this is
             a PHY-viewport-based interface, but some platform may have

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

@@ -52,6 +52,8 @@
 #define IMX95_PCIE_REF_CLKEN			BIT(23)
 #define IMX95_PCIE_PHY_CR_PARA_SEL		BIT(9)
 #define IMX95_PCIE_SS_RW_REG_1			0xf4
+#define IMX95_PCIE_CLKREQ_OVERRIDE_EN		BIT(8)
+#define IMX95_PCIE_CLKREQ_OVERRIDE_VAL		BIT(9)
 #define IMX95_PCIE_SYS_AUX_PWR_DET		BIT(31)
 
 #define IMX95_PE0_GEN_CTRL_1			0x1050
@@ -137,6 +139,7 @@ struct imx_pcie_drvdata {
 	int (*enable_ref_clk)(struct imx_pcie *pcie, bool enable);
 	int (*core_reset)(struct imx_pcie *pcie, bool assert);
 	int (*wait_pll_lock)(struct imx_pcie *pcie);
+	void (*clr_clkreq_override)(struct imx_pcie *pcie);
 	const struct dw_pcie_host_ops *ops;
 };
 
@@ -150,6 +153,8 @@ struct imx_pcie {
 	struct gpio_desc	*reset_gpiod;
 	struct clk_bulk_data	*clks;
 	int			num_clks;
+	bool			supports_clkreq;
+	bool			enable_ext_refclk;
 	struct regmap		*iomuxc_gpr;
 	u16			msi_ctrl;
 	u32			controller_id;
@@ -242,6 +247,8 @@ static unsigned int imx_pcie_grp_offset(const struct imx_pcie *imx_pcie)
 
 static int imx95_pcie_init_phy(struct imx_pcie *imx_pcie)
 {
+	bool ext = imx_pcie->enable_ext_refclk;
+
 	/*
 	 * ERR051624: The Controller Without Vaux Cannot Exit L23 Ready
 	 * Through Beacon or PERST# De-assertion
@@ -260,13 +267,12 @@ static int imx95_pcie_init_phy(struct imx_pcie *imx_pcie)
 			IMX95_PCIE_PHY_CR_PARA_SEL,
 			IMX95_PCIE_PHY_CR_PARA_SEL);
 
-	regmap_update_bits(imx_pcie->iomuxc_gpr,
-			   IMX95_PCIE_PHY_GEN_CTRL,
-			   IMX95_PCIE_REF_USE_PAD, 0);
-	regmap_update_bits(imx_pcie->iomuxc_gpr,
-			   IMX95_PCIE_SS_RW_REG_0,
+	regmap_update_bits(imx_pcie->iomuxc_gpr, IMX95_PCIE_PHY_GEN_CTRL,
+			   ext ? IMX95_PCIE_REF_USE_PAD : 0,
+			   IMX95_PCIE_REF_USE_PAD);
+	regmap_update_bits(imx_pcie->iomuxc_gpr, IMX95_PCIE_SS_RW_REG_0,
 			   IMX95_PCIE_REF_CLKEN,
-			   IMX95_PCIE_REF_CLKEN);
+			   ext ? 0 : IMX95_PCIE_REF_CLKEN);
 
 	return 0;
 }
@@ -686,7 +692,7 @@ static int imx6q_pcie_enable_ref_clk(struct imx_pcie *imx_pcie, bool enable)
 	return 0;
 }
 
-static int imx8mm_pcie_enable_ref_clk(struct imx_pcie *imx_pcie, bool enable)
+static void imx8mm_pcie_clkreq_override(struct imx_pcie *imx_pcie, bool enable)
 {
 	int offset = imx_pcie_grp_offset(imx_pcie);
 
@@ -696,6 +702,11 @@ static int imx8mm_pcie_enable_ref_clk(struct imx_pcie *imx_pcie, bool enable)
 	regmap_update_bits(imx_pcie->iomuxc_gpr, offset,
 			   IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN,
 			   enable ? IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN : 0);
+}
+
+static int imx8mm_pcie_enable_ref_clk(struct imx_pcie *imx_pcie, bool enable)
+{
+	imx8mm_pcie_clkreq_override(imx_pcie, enable);
 	return 0;
 }
 
@@ -707,6 +718,32 @@ static int imx7d_pcie_enable_ref_clk(struct imx_pcie *imx_pcie, bool enable)
 	return 0;
 }
 
+static void imx95_pcie_clkreq_override(struct imx_pcie *imx_pcie, bool enable)
+{
+	regmap_update_bits(imx_pcie->iomuxc_gpr, IMX95_PCIE_SS_RW_REG_1,
+			   IMX95_PCIE_CLKREQ_OVERRIDE_EN,
+			   enable ? IMX95_PCIE_CLKREQ_OVERRIDE_EN : 0);
+	regmap_update_bits(imx_pcie->iomuxc_gpr, IMX95_PCIE_SS_RW_REG_1,
+			   IMX95_PCIE_CLKREQ_OVERRIDE_VAL,
+			   enable ? IMX95_PCIE_CLKREQ_OVERRIDE_VAL : 0);
+}
+
+static int imx95_pcie_enable_ref_clk(struct imx_pcie *imx_pcie, bool enable)
+{
+	imx95_pcie_clkreq_override(imx_pcie, enable);
+	return 0;
+}
+
+static void imx8mm_pcie_clr_clkreq_override(struct imx_pcie *imx_pcie)
+{
+	imx8mm_pcie_clkreq_override(imx_pcie, false);
+}
+
+static void imx95_pcie_clr_clkreq_override(struct imx_pcie *imx_pcie)
+{
+	imx95_pcie_clkreq_override(imx_pcie, false);
+}
+
 static int imx_pcie_clk_enable(struct imx_pcie *imx_pcie)
 {
 	struct dw_pcie *pci = imx_pcie->pci;
@@ -1323,6 +1360,12 @@ static void imx_pcie_host_post_init(struct dw_pcie_rp *pp)
 		dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
 		dw_pcie_dbi_ro_wr_dis(pci);
 	}
+
+	/* Clear CLKREQ# override if supports_clkreq is true and link is up */
+	if (dw_pcie_link_up(pci) && imx_pcie->supports_clkreq) {
+		if (imx_pcie->drvdata->clr_clkreq_override)
+			imx_pcie->drvdata->clr_clkreq_override(imx_pcie);
+	}
 }
 
 /*
@@ -1606,7 +1649,7 @@ static int imx_pcie_probe(struct platform_device *pdev)
 	struct imx_pcie *imx_pcie;
 	struct device_node *np;
 	struct device_node *node = dev->of_node;
-	int ret, domain;
+	int i, ret, domain;
 	u16 val;
 
 	imx_pcie = devm_kzalloc(dev, sizeof(*imx_pcie), GFP_KERNEL);
@@ -1657,6 +1700,9 @@ static int imx_pcie_probe(struct platform_device *pdev)
 	if (imx_pcie->num_clks < 0)
 		return dev_err_probe(dev, imx_pcie->num_clks,
 				     "failed to get clocks\n");
+	for (i = 0; i < imx_pcie->num_clks; i++)
+		if (strncmp(imx_pcie->clks[i].id, "extref", 6) == 0)
+			imx_pcie->enable_ext_refclk = true;
 
 	if (imx_check_flag(imx_pcie, IMX_PCIE_FLAG_HAS_PHYDRV)) {
 		imx_pcie->phy = devm_phy_get(dev, "pcie-phy");
@@ -1744,6 +1790,7 @@ static int imx_pcie_probe(struct platform_device *pdev)
 	/* Limit link speed */
 	pci->max_link_speed = 1;
 	of_property_read_u32(node, "fsl,max-link-speed", &pci->max_link_speed);
+	imx_pcie->supports_clkreq = of_property_read_bool(node, "supports-clkreq");
 
 	ret = devm_regulator_get_enable_optional(&pdev->dev, "vpcie3v3aux");
 	if (ret < 0 && ret != -ENODEV)
@@ -1881,6 +1928,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
 		.mode_mask[1] = IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE,
 		.init_phy = imx8mq_pcie_init_phy,
 		.enable_ref_clk = imx8mm_pcie_enable_ref_clk,
+		.clr_clkreq_override = imx8mm_pcie_clr_clkreq_override,
 	},
 	[IMX8MM] = {
 		.variant = IMX8MM,
@@ -1891,6 +1939,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
 		.mode_off[0] = IOMUXC_GPR12,
 		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
 		.enable_ref_clk = imx8mm_pcie_enable_ref_clk,
+		.clr_clkreq_override = imx8mm_pcie_clr_clkreq_override,
 	},
 	[IMX8MP] = {
 		.variant = IMX8MP,
@@ -1901,6 +1950,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
 		.mode_off[0] = IOMUXC_GPR12,
 		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
 		.enable_ref_clk = imx8mm_pcie_enable_ref_clk,
+		.clr_clkreq_override = imx8mm_pcie_clr_clkreq_override,
 	},
 	[IMX8Q] = {
 		.variant = IMX8Q,
@@ -1921,6 +1971,8 @@ static const struct imx_pcie_drvdata drvdata[] = {
 		.core_reset = imx95_pcie_core_reset,
 		.init_phy = imx95_pcie_init_phy,
 		.wait_pll_lock = imx95_pcie_wait_for_phy_pll_lock,
+		.enable_ref_clk = imx95_pcie_enable_ref_clk,
+		.clr_clkreq_override = imx95_pcie_clr_clkreq_override,
 	},
 	[IMX8MQ_EP] = {
 		.variant = IMX8MQ_EP,
@@ -1977,6 +2029,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
 		.core_reset = imx95_pcie_core_reset,
 		.wait_pll_lock = imx95_pcie_wait_for_phy_pll_lock,
 		.epc_features = &imx95_pcie_epc_features,
+		.enable_ref_clk = imx95_pcie_enable_ref_clk,
 		.mode = DW_PCIE_EP_TYPE,
 	},
 };

drivers/pci/controller/dwc/pcie-designware-host.c

@@ -1317,6 +1317,9 @@ int dw_pcie_resume_noirq(struct dw_pcie *pci)
 	if (ret)
 		return ret;
 
+	if (pci->pp.ops->post_init)
+		pci->pp.ops->post_init(&pci->pp);
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(dw_pcie_resume_noirq);