Merge branch 'pci/controller/dwc-imx6'

- Remove PERST# checking from pci_host_common_parse_port() so callers can
  decide whether to fall back to legacy DT binding with PERST# in the host
  bridge (Sherry Sun)

- Fix build issues when PCI_PWRCTRL_GENERIC or PCI_HOST_COMMON is a module
  (Arnd Bergmann)

- Create pwrctrl devices only once by doing it from imx_pcie_probe()
  instead of imx_pcie_host_init(), which is used during both probe and
  resume (Sherry Sun)

- Use 'dw_pcie_rp->skip_pwrctrl_off' to avoid powering off devices during
  suspend to preserve wakeup capability (Sherry Sun)

- Add runtime PM support for i.MX95 to allow dynamic power management when
  the link is idle (Richard Zhu)

* pci/controller/dwc-imx6:
  PCI: imx6: Add runtime PM support for i.MX95
  PCI: imx6: Add 'skip_pwrctrl_off' flag support
  PCI: imx6: Move pci_pwrctrl_create_devices() to imx_pcie_probe()
  PCI: imx6: Fix building against PCI_PWRCTRL_GENERIC
  PCI: imx6: Fix building against PCI_HOST_COMMON
  PCI: host-generic: Move legacy DT binding fallback decision to caller of pci_host_common_parse_ports()

3 files changed, 54 insertions, 49 deletions

diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
index aa0b784c85b4..49a7a2c50ca1 100644
--- a/drivers/pci/controller/dwc/Kconfig
+++ b/drivers/pci/controller/dwc/Kconfig
@@ -126,7 +126,9 @@ config PCI_IMX6_EP
 	depends on ARCH_MXC || COMPILE_TEST
 	depends on PCI_ENDPOINT
 	select PCIE_DW_EP
+	select PCI_HOST_COMMON
 	select PCI_IMX6
+	select PCI_PWRCTRL_GENERIC
 	help
 	  Enables support for the PCIe controller in the i.MX SoCs to
 	  work in endpoint mode. The PCI controller on i.MX is based
diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 98e1db751132..19a7b7349296 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -121,6 +121,7 @@ enum imx_pcie_variants {
 #define IMX_PCIE_FLAG_SKIP_L23_READY		BIT(12)
 /* Preserve MSI capability for platforms that require it */
 #define IMX_PCIE_FLAG_KEEP_MSI_CAP		BIT(13)
+#define IMX_PCIE_FLAG_PM_RUNTIME		BIT(14)
 
 #define imx_check_flag(pci, val)	(pci->drvdata->flags & val)
 
@@ -1318,6 +1319,18 @@ static void imx_pcie_assert_perst(struct imx_pcie *imx_pcie, bool assert)
 	}
 }
 
+static bool imx_pcie_perst_found(struct pci_host_bridge *bridge)
+{
+	struct pci_host_port *port;
+
+	list_for_each_entry(port, &bridge->ports, list) {
+		if (!list_empty(&port->perst))
+			return true;
+	}
+
+	return false;
+}
+
 static int imx_pcie_host_init(struct dw_pcie_rp *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
@@ -1330,15 +1343,12 @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp)
 		/* Parse Root Port nodes if present */
 		ret = pci_host_common_parse_ports(dev, bridge);
 		if (ret) {
-			if (ret != -ENODEV) {
-				dev_err(dev, "Failed to parse Root Port nodes: %d\n", ret);
-				return ret;
-			}
+			dev_err(dev, "Failed to parse Root Port nodes: %d\n", ret);
+			return ret;
+		}
 
-			/*
-			 * Fall back to legacy binding for DT backwards
-			 * compatibility
-			 */
+		/* Fall back to legacy binding for DT backwards compatibility */
+		if (!imx_pcie_perst_found(bridge)) {
 			ret = imx_pcie_parse_legacy_binding(imx_pcie);
 			if (ret)
 				return ret;
@@ -1373,16 +1383,12 @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp)
 		}
 	}
 
-	ret = pci_pwrctrl_create_devices(dev);
-	if (ret) {
-		dev_err(dev, "failed to create pwrctrl devices\n");
-		goto err_reg_disable;
-	}
-
-	ret = pci_pwrctrl_power_on_devices(dev);
-	if (ret) {
-		dev_err(dev, "failed to power on pwrctrl devices\n");
-		goto err_pwrctrl_destroy;
+	if (!pp->skip_pwrctrl_off) {
+		ret = pci_pwrctrl_power_on_devices(dev);
+		if (ret) {
+			dev_err(dev, "failed to power on pwrctrl devices\n");
+			goto err_reg_disable;
+		}
 	}
 
 	ret = imx_pcie_clk_enable(imx_pcie);
@@ -1451,10 +1457,8 @@ err_phy_exit:
 err_clk_disable:
 	imx_pcie_clk_disable(imx_pcie);
 err_pwrctrl_power_off:
-	pci_pwrctrl_power_off_devices(dev);
-err_pwrctrl_destroy:
-	if (ret != -EPROBE_DEFER)
-		pci_pwrctrl_destroy_devices(dev);
+	if (!pp->skip_pwrctrl_off)
+		pci_pwrctrl_power_off_devices(dev);
 err_reg_disable:
 	if (imx_pcie->vpcie)
 		regulator_disable(imx_pcie->vpcie);
@@ -1473,7 +1477,8 @@ static void imx_pcie_host_exit(struct dw_pcie_rp *pp)
 	}
 	imx_pcie_clk_disable(imx_pcie);
 
-	pci_pwrctrl_power_off_devices(pci->dev);
+	if (!pci->pp.skip_pwrctrl_off)
+		pci_pwrctrl_power_off_devices(pci->dev);
 	if (imx_pcie->vpcie)
 		regulator_disable(imx_pcie->vpcie);
 }
@@ -1945,11 +1950,15 @@ static int imx_pcie_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	ret = pci_pwrctrl_create_devices(dev);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to create pwrctrl devices\n");
+
 	pci->use_parent_dt_ranges = true;
 	if (imx_pcie->drvdata->mode == DW_PCIE_EP_TYPE) {
 		ret = imx_add_pcie_ep(imx_pcie, pdev);
 		if (ret < 0)
-			return ret;
+			goto err_pwrctrl_destroy;
 
 		/*
 		 * FIXME: Only single Device (EPF) is supported due to the
@@ -1957,6 +1966,13 @@ static int imx_pcie_probe(struct platform_device *pdev)
 		 */
 		imx_pcie_add_lut_by_rid(imx_pcie, 0);
 	} else {
+		if (imx_pcie->drvdata->flags & IMX_PCIE_FLAG_PM_RUNTIME) {
+			pm_runtime_no_callbacks(dev);
+			ret = devm_pm_runtime_set_active_enabled(dev);
+			if (ret < 0)
+				return ret;
+		}
+
 		if (imx_check_flag(imx_pcie, IMX_PCIE_FLAG_SKIP_L23_READY))
 			pci->pp.skip_l23_ready = true;
 		if (imx_check_flag(imx_pcie, IMX_PCIE_FLAG_KEEP_MSI_CAP))
@@ -1964,7 +1980,7 @@ static int imx_pcie_probe(struct platform_device *pdev)
 		pci->pp.use_atu_msg = true;
 		ret = dw_pcie_host_init(&pci->pp);
 		if (ret < 0)
-			return ret;
+			goto err_pwrctrl_destroy;
 
 		if (pci_msi_enabled()) {
 			u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_MSI);
@@ -1976,6 +1992,11 @@ static int imx_pcie_probe(struct platform_device *pdev)
 	}
 
 	return 0;
+
+err_pwrctrl_destroy:
+	if (ret != -EPROBE_DEFER)
+		pci_pwrctrl_destroy_devices(dev);
+	return ret;
 }
 
 static void imx_pcie_shutdown(struct platform_device *pdev)
@@ -2100,6 +2121,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
 		.flags = IMX_PCIE_FLAG_HAS_SERDES |
 			 IMX_PCIE_FLAG_HAS_LUT |
 			 IMX_PCIE_FLAG_8GT_ECN_ERR051586 |
+			 IMX_PCIE_FLAG_PM_RUNTIME |
 			 IMX_PCIE_FLAG_SUPPORTS_SUSPEND,
 		.ltssm_off = IMX95_PE0_GEN_CTRL_3,
 		.ltssm_mask = IMX95_PCIE_LTSSM_EN,
diff --git a/drivers/pci/controller/pci-host-common.c b/drivers/pci/controller/pci-host-common.c
index 2ce6f4b66133..da6636505c74 100644
--- a/drivers/pci/controller/pci-host-common.c
+++ b/drivers/pci/controller/pci-host-common.c
@@ -108,8 +108,7 @@ parse_child_node:
  * dependencies and the driver may fail to operate if required resources
  * are missing.
  *
- * Return: 0 on success, -ENODEV if PERST# found in RC node (legacy binding
- * should be used), Other negative error codes on failure.
+ * Return: 0 on success, negative error codes on failure.
  */
 static int pci_host_common_parse_port(struct device *dev,
 				      struct pci_host_bridge *bridge,
@@ -128,22 +127,6 @@ static int pci_host_common_parse_port(struct device *dev,
 	if (ret)
 		return ret;
 
-	/*
-	 * 1. PERST# found in RP or its child nodes - list is not empty,
-	 *    continue
-	 *
-	 * 2. PERST# not found in RP/children, but found in RC node -
-	 *    return -ENODEV to fallback legacy binding
-	 *
-	 * 3. PERST# not found anywhere - list is empty, continue (optional
-	 *    PERST#)
-	 */
-	if (list_empty(&port->perst)) {
-		if (of_property_present(dev->of_node, "reset-gpios") ||
-		    of_property_present(dev->of_node, "reset-gpio"))
-			return -ENODEV;
-	}
-
 	INIT_LIST_HEAD(&port->list);
 	list_add_tail(&port->list, &bridge->ports);
 
@@ -158,13 +141,11 @@ static int pci_host_common_parse_port(struct device *dev,
  * Iterate through child nodes of the host bridge and parse Root Port
  * properties (currently only reset GPIOs).
  *
- * Return: 0 on success, -ENODEV if no ports found or PERST# found in RC
- * node (legacy binding should be used), Other negative error codes on
- * failure.
+ * Return: 0 on success or ports not found, negative error codes on failure.
  */
 int pci_host_common_parse_ports(struct device *dev, struct pci_host_bridge *bridge)
 {
-	int ret = -ENODEV;
+	int ret = 0;
 
 	for_each_available_child_of_node_scoped(dev->of_node, of_port) {
 		if (!of_node_is_type(of_port, "pci"))
@@ -174,8 +155,8 @@ int pci_host_common_parse_ports(struct device *dev, struct pci_host_bridge *brid
 			goto err_cleanup;
 	}
 
-	if (ret)
-		return ret;
+	if (list_empty(&bridge->ports))
+		return 0;
 
 	return devm_add_action_or_reset(dev, pci_host_common_delete_ports,
 					&bridge->ports);