[PATCH v2 0/5] Add STM32MP25 PCIe drivers

[PATCH v2 0/5] Add STM32MP25 PCIe drivers

[Christian Bruel]

This patch series adds PCIe drivers STM32MP25 SoC from STMicrolectronics
and respective yaml schema for the root complex and device modes.

Changes in v2:
   - Fix st,stm32-pcie-common.yaml dt_binding_check	

Changes in v1:
   Address comments from Rob Herring and Bjorn Helgaas:
   - Drop st,limit-mrrs and st,max-payload-size from this patchset
   - Remove single reset and clocks binding names and misc yaml cleanups
   - Split RC/EP common bindings to a separate schema file
   - Use correct PCIE_T_PERST_CLK_US and PCIE_T_RRS_READY_MS defines
   - Use .remove instead of .remove_new
   - Fix bar reset sequence in EP driver
   - Use cleanup blocks for error handling
   - Cosmetic fixes
   
Christian Bruel (5):
  dt-bindings: PCI: Add STM32MP25 PCIe root complex bindings
  PCI: stm32: Add PCIe host support for STM32MP25
  dt-bindings: PCI: Add STM32MP25 PCIe endpoint bindings
  PCI: stm32: Add PCIe endpoint support for STM32MP25
  MAINTAINERS: add entry for ST STM32MP25 PCIe drivers

 .../bindings/pci/st,stm32-pcie-common.yaml    |  45 ++
 .../bindings/pci/st,stm32-pcie-ep.yaml        |  61 +++
 .../bindings/pci/st,stm32-pcie-host.yaml      |  99 ++++
 MAINTAINERS                                   |   7 +
 drivers/pci/controller/dwc/Kconfig            |  24 +
 drivers/pci/controller/dwc/Makefile           |   2 +
 drivers/pci/controller/dwc/pcie-stm32-ep.c    | 445 ++++++++++++++++++
 drivers/pci/controller/dwc/pcie-stm32.c       | 402 ++++++++++++++++
 drivers/pci/controller/dwc/pcie-stm32.h       |  17 +
 9 files changed, 1102 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml
 create mode 100644 Documentation/devicetree/bindings/pci/st,stm32-pcie-ep.yaml
 create mode 100644 Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml
 create mode 100644 drivers/pci/controller/dwc/pcie-stm32-ep.c
 create mode 100644 drivers/pci/controller/dwc/pcie-stm32.c
 create mode 100644 drivers/pci/controller/dwc/pcie-stm32.h

-- 
2.34.1

[PATCH v2 1/5] dt-bindings: PCI: Add STM32MP25 PCIe root complex bindings

[Christian Bruel]

Document the bindings for STM32MP25 PCIe Controller configured in
root complex mode.

Supports 4 legacy interrupts and MSI interrupts from the ARM
GICv2m controller.

STM32 PCIe may be in a power domain which is the case for the STM32MP25
based boards.

Supports wake# from wake-gpios

Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
---
 .../bindings/pci/st,stm32-pcie-common.yaml    | 45 +++++++++
 .../bindings/pci/st,stm32-pcie-host.yaml      | 99 +++++++++++++++++++
 2 files changed, 144 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml
 create mode 100644 Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml

diff --git a/Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml b/Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml
new file mode 100644
index 000000000000..479c03134da3
--- /dev/null
+++ b/Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml
@@ -0,0 +1,45 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pci/st,stm32-pcie-common.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: STM32MP25 PCIe RC/EP controller
+
+maintainers:
+  - Christian Bruel <christian.bruel@foss.st.com>
+
+description:
+  STM32MP25 PCIe RC/EP common properties
+
+properties:
+  clocks:
+    maxItems: 1
+    description: PCIe system clock
+
+  resets:
+    maxItems: 1
+
+  phys:
+    maxItems: 1
+
+  phy-names:
+    const: pcie-phy
+
+  power-domains:
+    maxItems: 1
+
+  access-controllers:
+    maxItems: 1
+
+  reset-gpios:
+    description: GPIO controlled connection to PERST# signal
+    maxItems: 1
+
+required:
+  - clocks
+  - resets
+  - phys
+  - phy-names
+
+additionalProperties: true
diff --git a/Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml b/Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml
new file mode 100644
index 000000000000..18083cc69024
--- /dev/null
+++ b/Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml
@@ -0,0 +1,99 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pci/st,stm32-pcie-host.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: STM32MP25 PCIe root complex driver
+
+maintainers:
+  - Christian Bruel <christian.bruel@foss.st.com>
+
+description:
+  PCIe root complex controller based on the Synopsys DesignWare PCIe core.
+
+allOf:
+  - $ref: /schemas/pci/snps,dw-pcie.yaml#
+  - $ref: /schemas/pci/st,stm32-pcie-common.yaml#
+
+select:
+  properties:
+    compatible:
+      const: st,stm32mp25-pcie-rc
+  required:
+    - compatible
+
+properties:
+  compatible:
+    const: st,stm32mp25-pcie-rc
+
+  reg:
+    items:
+      - description: Data Bus Interface (DBI) registers.
+      - description: PCIe configuration registers.
+
+  reg-names:
+    items:
+      - const: dbi
+      - const: config
+
+  num-lanes:
+    const: 1
+
+  msi-parent:
+    maxItems: 1
+
+  wake-gpios:
+    description: GPIO controlled connection to WAKE# input signal
+    maxItems: 1
+
+  wakeup-source: true
+
+dependentRequired:
+  wakeup-source: [ wake-gpios ]
+
+required:
+  - interrupt-map
+  - interrupt-map-mask
+  - ranges
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/st,stm32mp25-rcc.h>
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/phy/phy.h>
+    #include <dt-bindings/reset/st,stm32mp25-rcc.h>
+
+    pcie@48400000 {
+        compatible = "st,stm32mp25-pcie-rc";
+        device_type = "pci";
+        num-lanes = <1>;
+        reg = <0x48400000 0x400000>,
+              <0x10000000 0x10000>;
+        reg-names = "dbi", "config";
+        #interrupt-cells = <1>;
+        interrupt-map-mask = <0 0 0 7>;
+        interrupt-map = <0 0 0 1 &intc 0 0 GIC_SPI 264 IRQ_TYPE_LEVEL_HIGH>,
+                        <0 0 0 2 &intc 0 0 GIC_SPI 265 IRQ_TYPE_LEVEL_HIGH>,
+                        <0 0 0 3 &intc 0 0 GIC_SPI 266 IRQ_TYPE_LEVEL_HIGH>,
+                        <0 0 0 4 &intc 0 0 GIC_SPI 267 IRQ_TYPE_LEVEL_HIGH>;
+        #address-cells = <3>;
+        #size-cells = <2>;
+        ranges = <0x01000000 0 0x10010000 0x10010000 0 0x10000>,
+                 <0x02000000 0 0x10020000 0x10020000 0 0x7fe0000>,
+                 <0x42000000 0 0x18000000 0x18000000 0 0x8000000>;
+        clocks = <&rcc CK_BUS_PCIE>;
+        phys = <&combophy PHY_TYPE_PCIE>;
+        phy-names = "pcie-phy";
+        resets = <&rcc PCIE_R>;
+        msi-parent = <&v2m0>;
+        wakeup-source;
+        wake-gpios = <&gpioh 5 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
+        reset-gpios = <&gpioj 8 GPIO_ACTIVE_LOW>;
+        access-controllers = <&rifsc 68>;
+        power-domains = <&CLUSTER_PD>;
+    };
+
-- 
2.34.1

[PATCH v2 2/5] PCI: stm32: Add PCIe host support for STM32MP25

[Christian Bruel]

Add driver for the STM32MP25 SoC PCIe Gen2 controller based on the
DesignWare PCIe core.

Supports MSI via GICv2m, Single Virtual Channel, Single Function

Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
---
 drivers/pci/controller/dwc/Kconfig      |  12 +
 drivers/pci/controller/dwc/Makefile     |   1 +
 drivers/pci/controller/dwc/pcie-stm32.c | 402 ++++++++++++++++++++++++
 drivers/pci/controller/dwc/pcie-stm32.h |  15 +
 4 files changed, 430 insertions(+)
 create mode 100644 drivers/pci/controller/dwc/pcie-stm32.c
 create mode 100644 drivers/pci/controller/dwc/pcie-stm32.h

diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
index b6d6778b0698..0c18879b604c 100644
--- a/drivers/pci/controller/dwc/Kconfig
+++ b/drivers/pci/controller/dwc/Kconfig
@@ -389,6 +389,18 @@ config PCIE_SPEAR13XX
 	help
 	  Say Y here if you want PCIe support on SPEAr13XX SoCs.
 
+config PCIE_STM32
+	tristate "STMicroelectronics STM32MP25 PCIe Controller (host mode)"
+	depends on ARCH_STM32 || COMPILE_TEST
+	depends on PCI_MSI
+	select PCIE_DW_HOST
+	help
+	  Enables support for the DesignWare core based PCIe host controller
+	  found in STM32MP25 SoC.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called pcie-stm32.
+
 config PCI_DRA7XX
 	tristate
 
diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
index a8308d9ea986..576d99cb3bc5 100644
--- a/drivers/pci/controller/dwc/Makefile
+++ b/drivers/pci/controller/dwc/Makefile
@@ -28,6 +28,7 @@ obj-$(CONFIG_PCIE_UNIPHIER) += pcie-uniphier.o
 obj-$(CONFIG_PCIE_UNIPHIER_EP) += pcie-uniphier-ep.o
 obj-$(CONFIG_PCIE_VISCONTI_HOST) += pcie-visconti.o
 obj-$(CONFIG_PCIE_RCAR_GEN4) += pcie-rcar-gen4.o
+obj-$(CONFIG_PCIE_STM32) += pcie-stm32.o
 
 # The following drivers are for devices that use the generic ACPI
 # pci_root.c driver but don't support standard ECAM config access.
diff --git a/drivers/pci/controller/dwc/pcie-stm32.c b/drivers/pci/controller/dwc/pcie-stm32.c
new file mode 100644
index 000000000000..fa787406c0e4
--- /dev/null
+++ b/drivers/pci/controller/dwc/pcie-stm32.c
@@ -0,0 +1,402 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * STMicroelectronics STM32MP25 PCIe root complex driver.
+ *
+ * Copyright (C) 2024 STMicroelectronics
+ * Author: Christian Bruel <christian.bruel@foss.st.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_platform.h>
+#include <linux/phy/phy.h>
+#include <linux/pinctrl/devinfo.h>
+#include <linux/pm_runtime.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include "pcie-designware.h"
+#include "pcie-stm32.h"
+#include "../../pci.h"
+
+struct stm32_pcie {
+	struct dw_pcie *pci;
+	struct regmap *regmap;
+	struct reset_control *rst;
+	struct phy *phy;
+	struct clk *clk;
+	struct gpio_desc *perst_gpio;
+	struct gpio_desc *wake_gpio;
+	unsigned int wake_irq;
+	bool link_is_up;
+};
+
+static int stm32_pcie_start_link(struct dw_pcie *pci)
+{
+	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
+	u32 ret;
+
+	if (stm32_pcie->perst_gpio) {
+		/* Make sure PERST# is asserted. */
+		gpiod_set_value(stm32_pcie->perst_gpio, 1);
+
+		fsleep(PCIE_T_PERST_CLK_US);
+		gpiod_set_value(stm32_pcie->perst_gpio, 0);
+	}
+
+	ret = regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
+				 STM32MP25_PCIECR_LTSSM_EN,
+				 STM32MP25_PCIECR_LTSSM_EN);
+
+	if (stm32_pcie->perst_gpio)
+		msleep(PCIE_T_RRS_READY_MS);
+
+	return ret;
+}
+
+static void stm32_pcie_stop_link(struct dw_pcie *pci)
+{
+	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
+
+	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
+			   STM32MP25_PCIECR_LTSSM_EN, 0);
+
+	/* Assert PERST# */
+	if (stm32_pcie->perst_gpio)
+		gpiod_set_value(stm32_pcie->perst_gpio, 1);
+}
+
+static int stm32_pcie_suspend(struct device *dev)
+{
+	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev) || device_wakeup_path(dev))
+		enable_irq_wake(stm32_pcie->wake_irq);
+
+	return 0;
+}
+
+static int stm32_pcie_resume(struct device *dev)
+{
+	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev) || device_wakeup_path(dev))
+		disable_irq_wake(stm32_pcie->wake_irq);
+
+	return 0;
+}
+
+static int stm32_pcie_suspend_noirq(struct device *dev)
+{
+	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
+
+	stm32_pcie->link_is_up = dw_pcie_link_up(stm32_pcie->pci);
+
+	stm32_pcie_stop_link(stm32_pcie->pci);
+	clk_disable_unprepare(stm32_pcie->clk);
+
+	if (!device_may_wakeup(dev) && !device_wakeup_path(dev))
+		phy_exit(stm32_pcie->phy);
+
+	return pinctrl_pm_select_sleep_state(dev);
+}
+
+static int stm32_pcie_resume_noirq(struct device *dev)
+{
+	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
+	struct dw_pcie *pci = stm32_pcie->pci;
+	struct dw_pcie_rp *pp = &pci->pp;
+	int ret;
+
+	/* init_state must be called first to force clk_req# gpio when no
+	 * device is plugged.
+	 */
+	if (!IS_ERR(dev->pins->init_state))
+		ret = pinctrl_select_state(dev->pins->p, dev->pins->init_state);
+	else
+		ret = pinctrl_pm_select_default_state(dev);
+
+	if (ret) {
+		dev_err(dev, "Failed to activate pinctrl pm state: %d\n", ret);
+		return ret;
+	}
+
+	if (!device_may_wakeup(dev) && !device_wakeup_path(dev)) {
+		ret = phy_init(stm32_pcie->phy);
+		if (ret) {
+			pinctrl_pm_select_default_state(dev);
+			return ret;
+		}
+	}
+
+	ret = clk_prepare_enable(stm32_pcie->clk);
+	if (ret)
+		goto clk_err;
+
+	ret = dw_pcie_setup_rc(pp);
+	if (ret)
+		goto pcie_err;
+
+	if (stm32_pcie->link_is_up) {
+		ret = stm32_pcie_start_link(stm32_pcie->pci);
+		if (ret)
+			goto pcie_err;
+
+		/* Ignore errors, the link may come up later */
+		dw_pcie_wait_for_link(stm32_pcie->pci);
+	}
+
+	pinctrl_pm_select_default_state(dev);
+
+	return 0;
+
+pcie_err:
+	dw_pcie_host_deinit(pp);
+	clk_disable_unprepare(stm32_pcie->clk);
+clk_err:
+	phy_exit(stm32_pcie->phy);
+	pinctrl_pm_select_default_state(dev);
+
+	return ret;
+}
+
+static const struct dev_pm_ops stm32_pcie_pm_ops = {
+	NOIRQ_SYSTEM_SLEEP_PM_OPS(stm32_pcie_suspend_noirq,
+				  stm32_pcie_resume_noirq)
+	SYSTEM_SLEEP_PM_OPS(stm32_pcie_suspend, stm32_pcie_resume)
+};
+
+static const struct dw_pcie_host_ops stm32_pcie_host_ops = {
+};
+
+static const struct dw_pcie_ops dw_pcie_ops = {
+	.start_link = stm32_pcie_start_link,
+	.stop_link = stm32_pcie_stop_link
+};
+
+static irqreturn_t stm32_pcie_wake_irq_handler(int irq, void *priv)
+{
+	struct stm32_pcie *stm32_pcie = priv;
+	struct device *dev = stm32_pcie->pci->dev;
+
+	dev_dbg(dev, "PCIe host wakeup by EP");
+
+	/* Notify PM core we are wakeup source */
+	pm_wakeup_event(dev, 0);
+	pm_system_wakeup();
+
+	return IRQ_HANDLED;
+}
+
+static int stm32_add_pcie_port(struct stm32_pcie *stm32_pcie,
+			       struct platform_device *pdev)
+{
+	struct dw_pcie *pci = stm32_pcie->pci;
+	struct device *dev = pci->dev;
+	struct dw_pcie_rp *pp = &pci->pp;
+	int ret;
+
+	ret = phy_set_mode(stm32_pcie->phy, PHY_MODE_PCIE);
+	if (ret)
+		return ret;
+
+	ret = phy_init(stm32_pcie->phy);
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
+				 STM32MP25_PCIECR_TYPE_MASK,
+				 STM32MP25_PCIECR_RC);
+	if (ret)
+		goto phy_disable;
+
+	reset_control_assert(stm32_pcie->rst);
+	reset_control_deassert(stm32_pcie->rst);
+
+	ret = clk_prepare_enable(stm32_pcie->clk);
+	if (ret) {
+		dev_err(dev, "Core clock enable failed %d\n", ret);
+		goto phy_disable;
+	}
+
+	pp->ops = &stm32_pcie_host_ops;
+	ret = dw_pcie_host_init(pp);
+	if (ret) {
+		dev_err(dev, "Failed to initialize host: %d\n", ret);
+		clk_disable_unprepare(stm32_pcie->clk);
+		goto phy_disable;
+	}
+
+	return 0;
+
+phy_disable:
+	phy_exit(stm32_pcie->phy);
+
+	return ret;
+}
+
+static int stm32_pcie_probe(struct platform_device *pdev)
+{
+	struct stm32_pcie *stm32_pcie;
+	struct dw_pcie *dw;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = pdev->dev.of_node;
+	int ret;
+
+	stm32_pcie = devm_kzalloc(dev, sizeof(*stm32_pcie), GFP_KERNEL);
+	if (!stm32_pcie)
+		return -ENOMEM;
+
+	dw = devm_kzalloc(dev, sizeof(*dw), GFP_KERNEL);
+	if (!dw)
+		return -ENOMEM;
+	stm32_pcie->pci = dw;
+
+	dw->dev = dev;
+	dw->ops = &dw_pcie_ops;
+
+	stm32_pcie->regmap = syscon_regmap_lookup_by_compatible("st,stm32mp25-syscfg");
+	if (IS_ERR(stm32_pcie->regmap))
+		return dev_err_probe(dev, PTR_ERR(stm32_pcie->regmap),
+				     "No syscfg specified\n");
+
+	stm32_pcie->phy = devm_phy_get(dev, "pcie-phy");
+	if (IS_ERR(stm32_pcie->phy))
+		return dev_err_probe(dev, PTR_ERR(stm32_pcie->phy),
+				     "Failed to get pcie-phy\n");
+
+	stm32_pcie->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(stm32_pcie->clk))
+		return dev_err_probe(dev, PTR_ERR(stm32_pcie->clk),
+				     "Failed to get PCIe clock source\n");
+
+	stm32_pcie->rst = devm_reset_control_get_exclusive(dev, NULL);
+	if (IS_ERR(stm32_pcie->rst))
+		return dev_err_probe(dev, PTR_ERR(stm32_pcie->rst),
+				     "Failed to get PCIe reset\n");
+
+	stm32_pcie->perst_gpio = devm_gpiod_get_optional(dev, "reset",
+							 GPIOD_OUT_HIGH);
+	if (IS_ERR(stm32_pcie->perst_gpio))
+		return dev_err_probe(dev, PTR_ERR(stm32_pcie->perst_gpio),
+				     "Failed to get reset GPIO\n");
+
+	platform_set_drvdata(pdev, stm32_pcie);
+
+	if (device_property_read_bool(dev, "wakeup-source")) {
+		stm32_pcie->wake_gpio = devm_gpiod_get_optional(dev, "wake",
+								GPIOD_IN);
+		if (IS_ERR(stm32_pcie->wake_gpio))
+			return dev_err_probe(dev, PTR_ERR(stm32_pcie->wake_gpio),
+					     "Failed to get wake GPIO\n");
+	}
+
+	if (stm32_pcie->wake_gpio) {
+		stm32_pcie->wake_irq = gpiod_to_irq(stm32_pcie->wake_gpio);
+
+		ret = devm_request_threaded_irq(&pdev->dev,
+						stm32_pcie->wake_irq, NULL,
+						stm32_pcie_wake_irq_handler,
+						IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+						"wake_irq", stm32_pcie);
+
+		if (ret)
+			return dev_err_probe(dev, ret, "Failed to request WAKE IRQ: %d\n", ret);
+	}
+
+	ret = devm_pm_runtime_enable(dev);
+	if (ret < 0) {
+		dev_err(dev, "Failed to enable runtime PM %d\n", ret);
+		return ret;
+	}
+
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret < 0) {
+		dev_err(dev, "Failed to get runtime PM %d\n", ret);
+		return ret;
+	}
+
+	ret = stm32_add_pcie_port(stm32_pcie, pdev);
+	if (ret)  {
+		pm_runtime_put_sync(&pdev->dev);
+		return ret;
+	}
+
+	if (stm32_pcie->wake_gpio)
+		device_set_wakeup_capable(dev, true);
+
+	return 0;
+}
+
+static void stm32_pcie_remove(struct platform_device *pdev)
+{
+	struct stm32_pcie *stm32_pcie = platform_get_drvdata(pdev);
+	struct dw_pcie_rp *pp = &stm32_pcie->pci->pp;
+
+	if (stm32_pcie->wake_gpio)
+		device_init_wakeup(&pdev->dev, false);
+
+	dw_pcie_host_deinit(pp);
+	clk_disable_unprepare(stm32_pcie->clk);
+
+	phy_exit(stm32_pcie->phy);
+
+	pm_runtime_put_sync(&pdev->dev);
+}
+
+static const struct of_device_id stm32_pcie_of_match[] = {
+	{ .compatible = "st,stm32mp25-pcie-rc" },
+	{},
+};
+
+static struct platform_driver stm32_pcie_driver = {
+	.probe = stm32_pcie_probe,
+	.remove = stm32_pcie_remove,
+	.driver = {
+		.name = "stm32-pcie",
+		.of_match_table = stm32_pcie_of_match,
+		.pm		= &stm32_pcie_pm_ops,
+	},
+};
+
+static bool is_stm32_pcie_driver(struct device *dev)
+{
+	/* PCI bridge */
+	dev = get_device(dev);
+
+	/* Platform driver */
+	dev = get_device(dev->parent);
+
+	return (dev->driver == &stm32_pcie_driver.driver);
+}
+
+/*
+ * DMA masters can only access the first 4GB of memory space,
+ * so we setup the bus DMA limit accordingly.
+ */
+static int stm32_dma_limit(struct pci_dev *pdev, void *data)
+{
+	dev_dbg(&pdev->dev, "disabling DMA DAC for device");
+
+	pdev->dev.bus_dma_limit = DMA_BIT_MASK(32);
+
+	return 0;
+}
+
+static void quirk_stm32_dma_mask(struct pci_dev *pci)
+{
+	struct pci_dev *root_port;
+
+	root_port = pcie_find_root_port(pci);
+
+	if (root_port && is_stm32_pcie_driver(root_port->dev.parent))
+		pci_walk_bus(pci->bus, stm32_dma_limit, NULL);
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SYNOPSYS, 0x0550, quirk_stm32_dma_mask);
+
+module_platform_driver(stm32_pcie_driver);
+
+MODULE_AUTHOR("Christian Bruel <christian.bruel@foss.st.com>");
+MODULE_DESCRIPTION("STM32MP25 PCIe Controller driver");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(of, stm32_pcie_of_match);
diff --git a/drivers/pci/controller/dwc/pcie-stm32.h b/drivers/pci/controller/dwc/pcie-stm32.h
new file mode 100644
index 000000000000..3efd00937d3d
--- /dev/null
+++ b/drivers/pci/controller/dwc/pcie-stm32.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * ST PCIe driver definitions for STM32-MP25 SoC
+ *
+ * Copyright (C) 2024 STMicroelectronics - All Rights Reserved
+ * Author: Christian Bruel <christian.bruel@foss.st.com>
+ */
+
+#define to_stm32_pcie(x)	dev_get_drvdata((x)->dev)
+
+#define STM32MP25_PCIECR_TYPE_MASK	GENMASK(11, 8)
+#define STM32MP25_PCIECR_LTSSM_EN	BIT(2)
+#define STM32MP25_PCIECR_RC		BIT(10)
+
+#define SYSCFG_PCIECR			0x6000
-- 
2.34.1

[PATCH v2 3/5] dt-bindings: PCI: Add STM32MP25 PCIe endpoint bindings

[Christian Bruel]

STM32MP25 PCIe Controller is based on the DesignWare core configured as
end point mode from the SYSCFG register.

Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
---
 .../bindings/pci/st,stm32-pcie-ep.yaml        | 61 +++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pci/st,stm32-pcie-ep.yaml

diff --git a/Documentation/devicetree/bindings/pci/st,stm32-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/st,stm32-pcie-ep.yaml
new file mode 100644
index 000000000000..0da3ee012ba8
--- /dev/null
+++ b/Documentation/devicetree/bindings/pci/st,stm32-pcie-ep.yaml
@@ -0,0 +1,61 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pci/st,stm32-pcie-ep.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: STM32MP25 PCIe endpoint driver
+
+maintainers:
+  - Christian Bruel <christian.bruel@foss.st.com>
+
+description:
+  PCIe endpoint controller based on the Synopsys DesignWare PCIe core.
+
+allOf:
+  - $ref: /schemas/pci/snps,dw-pcie-ep.yaml#
+  - $ref: /schemas/pci/st,stm32-pcie-common.yaml#
+
+properties:
+  compatible:
+    const: st,stm32mp25-pcie-ep
+
+  reg:
+    items:
+      - description: Data Bus Interface (DBI) registers.
+      - description: PCIe configuration registers.
+
+  reg-names:
+    items:
+      - const: dbi
+      - const: addr_space
+
+required:
+  - reset-gpios
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/st,stm32mp25-rcc.h>
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/phy/phy.h>
+    #include <dt-bindings/reset/st,stm32mp25-rcc.h>
+
+    pcie-ep@48400000 {
+        compatible = "st,stm32mp25-pcie-ep";
+        num-lanes = <1>;
+        reg = <0x48400000 0x400000>,
+              <0x10000000 0x8000000>;
+        reg-names = "dbi", "addr_space";
+        clocks = <&rcc CK_BUS_PCIE>;
+        phys = <&combophy PHY_TYPE_PCIE>;
+        phy-names = "pcie-phy";
+        resets = <&rcc PCIE_R>;
+        pinctrl-names = "default", "init";
+        pinctrl-0 = <&pcie_pins_a>;
+        pinctrl-1 = <&pcie_init_pins_a>;
+        reset-gpios = <&gpioj 8 GPIO_ACTIVE_LOW>;
+        access-controllers = <&rifsc 68>;
+        power-domains = <&CLUSTER_PD>;
+    };
-- 
2.34.1

[PATCH v2 4/5] PCI: stm32: Add PCIe endpoint support for STM32MP25

[Christian Bruel]

Add driver to configure the STM32MP25 SoC PCIe Gen2 controller based on the
DesignWare PCIe core in endpoint mode.

Uses the common reference clock provided by the host.

Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
---
 drivers/pci/controller/dwc/Kconfig         |  12 +
 drivers/pci/controller/dwc/Makefile        |   1 +
 drivers/pci/controller/dwc/pcie-stm32-ep.c | 445 +++++++++++++++++++++
 drivers/pci/controller/dwc/pcie-stm32.h    |   2 +
 4 files changed, 460 insertions(+)
 create mode 100644 drivers/pci/controller/dwc/pcie-stm32-ep.c

diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
index 0c18879b604c..f5601c81b56c 100644
--- a/drivers/pci/controller/dwc/Kconfig
+++ b/drivers/pci/controller/dwc/Kconfig
@@ -401,6 +401,18 @@ config PCIE_STM32
 	  This driver can also be built as a module. If so, the module
 	  will be called pcie-stm32.
 
+config PCIE_STM32_EP
+	tristate "STMicroelectronics STM32MP25 PCIe Controller (endpoint mode)"
+	depends on ARCH_STM32 || COMPILE_TEST
+	depends on PCI_ENDPOINT
+	select PCIE_DW_EP
+	help
+	  Enables endpoint support for DesignWare core based PCIe controller in found
+	  in STM32MP25 SoC.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called pcie-stm32-ep.
+
 config PCI_DRA7XX
 	tristate
 
diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
index 576d99cb3bc5..caebd98f6dd3 100644
--- a/drivers/pci/controller/dwc/Makefile
+++ b/drivers/pci/controller/dwc/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_PCIE_UNIPHIER_EP) += pcie-uniphier-ep.o
 obj-$(CONFIG_PCIE_VISCONTI_HOST) += pcie-visconti.o
 obj-$(CONFIG_PCIE_RCAR_GEN4) += pcie-rcar-gen4.o
 obj-$(CONFIG_PCIE_STM32) += pcie-stm32.o
+obj-$(CONFIG_PCIE_STM32_EP) += pcie-stm32-ep.o
 
 # The following drivers are for devices that use the generic ACPI
 # pci_root.c driver but don't support standard ECAM config access.
diff --git a/drivers/pci/controller/dwc/pcie-stm32-ep.c b/drivers/pci/controller/dwc/pcie-stm32-ep.c
new file mode 100644
index 000000000000..27f5725a7e76
--- /dev/null
+++ b/drivers/pci/controller/dwc/pcie-stm32-ep.c
@@ -0,0 +1,445 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * STMicroelectronics STM32MP25 PCIe endpoint driver.
+ *
+ * Copyright (C) 2024 STMicroelectronics
+ * Author: Christian Bruel <christian.bruel@foss.st.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_platform.h>
+#include <linux/of_gpio.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include "pcie-designware.h"
+#include "pcie-stm32.h"
+
+#define STM32MP25_PCIECR_EP 0
+#define STM32MP25_PCIECR_REQ_RETRY_EN	BIT(3)
+
+enum stm32_pcie_ep_link_status {
+	STM32_PCIE_EP_LINK_DISABLED,
+	STM32_PCIE_EP_LINK_ENABLED,
+};
+
+struct stm32_pcie {
+	struct dw_pcie *pci;
+	struct regmap *regmap;
+	struct reset_control *rst;
+	struct phy *phy;
+	struct clk *clk;
+	struct gpio_desc *perst_gpio;
+	enum stm32_pcie_ep_link_status link_status;
+	unsigned int perst_irq;
+};
+
+static void stm32_pcie_ep_init(struct dw_pcie_ep *ep)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
+	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
+	enum pci_barno bar;
+
+	for (bar = 0; bar < PCI_STD_NUM_BARS; bar++)
+		dw_pcie_ep_reset_bar(pci, bar);
+
+	/* Defer Completion Requests until link started */
+	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
+			   STM32MP25_PCIECR_REQ_RETRY_EN,
+			   STM32MP25_PCIECR_REQ_RETRY_EN);
+}
+
+static int stm32_pcie_enable_link(struct dw_pcie *pci)
+{
+	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
+	int ret;
+
+	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
+			   STM32MP25_PCIECR_LTSSM_EN,
+			   STM32MP25_PCIECR_LTSSM_EN);
+
+	ret = dw_pcie_wait_for_link(pci);
+	if (ret)
+		return ret;
+
+	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
+			   STM32MP25_PCIECR_REQ_RETRY_EN,
+			   0);
+
+	return 0;
+}
+
+static void stm32_pcie_disable_link(struct dw_pcie *pci)
+{
+	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
+
+	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
+			   STM32MP25_PCIECR_REQ_RETRY_EN,
+			   STM32MP25_PCIECR_REQ_RETRY_EN);
+
+	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR, STM32MP25_PCIECR_LTSSM_EN, 0);
+}
+
+static int stm32_pcie_start_link(struct dw_pcie *pci)
+{
+	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
+	int ret;
+
+	if (stm32_pcie->link_status == STM32_PCIE_EP_LINK_ENABLED) {
+		dev_dbg(pci->dev, "Link is already enabled\n");
+		return 0;
+	}
+
+	ret = stm32_pcie_enable_link(pci);
+	if (ret) {
+		dev_err(pci->dev, "PCIe cannot establish link: %d\n", ret);
+		return ret;
+	}
+
+	stm32_pcie->link_status = STM32_PCIE_EP_LINK_ENABLED;
+
+	enable_irq(stm32_pcie->perst_irq);
+
+	return 0;
+}
+
+static void stm32_pcie_stop_link(struct dw_pcie *pci)
+{
+	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
+
+	if (stm32_pcie->link_status == STM32_PCIE_EP_LINK_DISABLED) {
+		dev_dbg(pci->dev, "Link is already disabled\n");
+		return;
+	}
+
+	disable_irq(stm32_pcie->perst_irq);
+
+	stm32_pcie_disable_link(pci);
+
+	stm32_pcie->link_status = STM32_PCIE_EP_LINK_DISABLED;
+}
+
+static int stm32_pcie_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
+				unsigned int type, u16 interrupt_num)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
+
+	switch (type) {
+	case PCI_IRQ_INTX:
+		return dw_pcie_ep_raise_intx_irq(ep, func_no);
+	case PCI_IRQ_MSI:
+		return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
+	default:
+		dev_err(pci->dev, "UNKNOWN IRQ type\n");
+		return -EINVAL;
+	}
+}
+
+static const struct pci_epc_features stm32_pcie_epc_features = {
+	.msi_capable = true,
+	.align = 1 << 16,
+};
+
+static const struct pci_epc_features*
+stm32_pcie_get_features(struct dw_pcie_ep *ep)
+{
+	return &stm32_pcie_epc_features;
+}
+
+static const struct dw_pcie_ep_ops stm32_pcie_ep_ops = {
+	.init = stm32_pcie_ep_init,
+	.raise_irq = stm32_pcie_raise_irq,
+	.get_features = stm32_pcie_get_features,
+};
+
+static const struct dw_pcie_ops dw_pcie_ops = {
+	.start_link = stm32_pcie_start_link,
+	.stop_link = stm32_pcie_stop_link,
+};
+
+static int stm32_pcie_enable_resources(struct stm32_pcie *stm32_pcie)
+{
+	int ret;
+
+	ret = phy_init(stm32_pcie->phy);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(stm32_pcie->clk);
+	if (ret)
+		phy_exit(stm32_pcie->phy);
+
+	return ret;
+}
+
+static void stm32_pcie_disable_resources(struct stm32_pcie *stm32_pcie)
+{
+	clk_disable_unprepare(stm32_pcie->clk);
+
+	phy_exit(stm32_pcie->phy);
+}
+
+static void stm32_pcie_perst_assert(struct dw_pcie *pci)
+{
+	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
+	struct device *dev = pci->dev;
+
+	dev_dbg(dev, "PERST asserted by host. Shutting down the PCIe link\n");
+
+	/*
+	 * Do not try to release resources if the PERST# is
+	 * asserted before the link is started.
+	 */
+	if (stm32_pcie->link_status == STM32_PCIE_EP_LINK_DISABLED) {
+		dev_dbg(pci->dev, "Link is already disabled\n");
+		return;
+	}
+
+	stm32_pcie_disable_link(pci);
+
+	stm32_pcie_disable_resources(stm32_pcie);
+
+	pm_runtime_put_sync(dev);
+
+	stm32_pcie->link_status = STM32_PCIE_EP_LINK_DISABLED;
+}
+
+static void stm32_pcie_perst_deassert(struct dw_pcie *pci)
+{
+	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
+	struct device *dev = pci->dev;
+	struct dw_pcie_ep *ep = &pci->ep;
+	int ret;
+
+	if (stm32_pcie->link_status == STM32_PCIE_EP_LINK_ENABLED) {
+		dev_dbg(pci->dev, "Link is already enabled\n");
+		return;
+	}
+
+	dev_dbg(dev, "PERST de-asserted by host. Starting link training\n");
+
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret < 0) {
+		dev_err(dev, "pm runtime resume failed: %d\n", ret);
+		return;
+	}
+
+	ret = stm32_pcie_enable_resources(stm32_pcie);
+	if (ret) {
+		dev_err(dev, "Failed to enable resources: %d\n", ret);
+		goto err_clk;
+	}
+
+	ret = dw_pcie_ep_init_registers(ep);
+	if (ret) {
+		dev_err(dev, "Failed to complete initialization: %d\n", ret);
+		goto err_init_regs;
+	}
+
+	pci_epc_init_notify(ep->epc);
+
+	ret = stm32_pcie_enable_link(pci);
+	if (ret) {
+		dev_err(dev, "PCIe Cannot establish link: %d\n", ret);
+		goto err_link;
+	}
+
+	stm32_pcie->link_status = STM32_PCIE_EP_LINK_ENABLED;
+
+	return;
+
+err_link:
+	pci_epc_deinit_notify(ep->epc);
+
+err_init_regs:
+	stm32_pcie_disable_resources(stm32_pcie);
+
+err_clk:
+	pm_runtime_put_sync(dev);
+}
+
+static irqreturn_t stm32_pcie_ep_perst_irq_thread(int irq, void *data)
+{
+	struct stm32_pcie *stm32_pcie = data;
+	struct dw_pcie *pci = stm32_pcie->pci;
+	u32 perst;
+
+	perst = gpiod_get_value(stm32_pcie->perst_gpio);
+	if (perst)
+		stm32_pcie_perst_assert(pci);
+	else
+		stm32_pcie_perst_deassert(pci);
+
+	return IRQ_HANDLED;
+}
+
+static int stm32_add_pcie_ep(struct stm32_pcie *stm32_pcie,
+			     struct platform_device *pdev)
+{
+	struct dw_pcie *pci = stm32_pcie->pci;
+	struct dw_pcie_ep *ep = &pci->ep;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	ret = regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
+				 STM32MP25_PCIECR_TYPE_MASK,
+				 STM32MP25_PCIECR_EP);
+	if (ret)
+		return ret;
+
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret < 0) {
+		dev_err(dev, "pm runtime resume failed: %d\n", ret);
+		return ret;
+	}
+
+	reset_control_assert(stm32_pcie->rst);
+	reset_control_deassert(stm32_pcie->rst);
+
+	ep->ops = &stm32_pcie_ep_ops;
+
+	ret = dw_pcie_ep_init(ep);
+	if (ret) {
+		dev_err(dev, "failed to initialize ep: %d\n", ret);
+		goto err_init;
+	}
+
+	ret = stm32_pcie_enable_resources(stm32_pcie);
+	if (ret) {
+		dev_err(dev, "failed to enable resources: %d\n", ret);
+		goto err_clk;
+	}
+
+	ret = dw_pcie_ep_init_registers(ep);
+	if (ret) {
+		dev_err(dev, "Failed to initialize DWC endpoint registers\n");
+		goto err_init_regs;
+	}
+
+	pci_epc_init_notify(ep->epc);
+
+	return 0;
+
+err_init_regs:
+	stm32_pcie_disable_resources(stm32_pcie);
+
+err_clk:
+	dw_pcie_ep_deinit(ep);
+
+err_init:
+	pm_runtime_put_sync(dev);
+	return ret;
+}
+
+static int stm32_pcie_probe(struct platform_device *pdev)
+{
+	struct stm32_pcie *stm32_pcie;
+	struct dw_pcie *dw;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	stm32_pcie = devm_kzalloc(dev, sizeof(*stm32_pcie), GFP_KERNEL);
+	if (!stm32_pcie)
+		return -ENOMEM;
+
+	dw = devm_kzalloc(dev, sizeof(*dw), GFP_KERNEL);
+	if (!dw)
+		return -ENOMEM;
+
+	stm32_pcie->pci = dw;
+
+	dw->dev = dev;
+	dw->ops = &dw_pcie_ops;
+
+	stm32_pcie->regmap = syscon_regmap_lookup_by_compatible("st,stm32mp25-syscfg");
+	if (IS_ERR(stm32_pcie->regmap))
+		return dev_err_probe(dev, PTR_ERR(stm32_pcie->regmap),
+				     "No syscfg specified\n");
+
+	stm32_pcie->phy = devm_phy_get(dev, "pcie-phy");
+	if (IS_ERR(stm32_pcie->phy))
+		return dev_err_probe(dev, PTR_ERR(stm32_pcie->phy),
+				     "failed to get pcie-phy\n");
+
+	stm32_pcie->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(stm32_pcie->clk))
+		return dev_err_probe(dev, PTR_ERR(stm32_pcie->clk),
+				     "Failed to get PCIe clock source\n");
+
+	stm32_pcie->rst = devm_reset_control_get_exclusive(dev, NULL);
+	if (IS_ERR(stm32_pcie->rst))
+		return dev_err_probe(dev, PTR_ERR(stm32_pcie->rst),
+				     "Failed to get PCIe reset\n");
+
+	stm32_pcie->perst_gpio = devm_gpiod_get(dev, "reset", GPIOD_IN);
+	if (IS_ERR(stm32_pcie->perst_gpio))
+		return dev_err_probe(dev, PTR_ERR(stm32_pcie->perst_gpio),
+				     "Failed to get reset GPIO\n");
+
+	ret = phy_set_mode(stm32_pcie->phy, PHY_MODE_PCIE);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, stm32_pcie);
+
+	ret = devm_pm_runtime_enable(dev);
+	if (ret < 0) {
+		dev_err(dev, "Failed to enable pm runtime %d\n", ret);
+		return ret;
+	}
+
+	stm32_pcie->perst_irq = gpiod_to_irq(stm32_pcie->perst_gpio);
+
+	/* Will be enabled in start_link when device is initialized. */
+	irq_set_status_flags(stm32_pcie->perst_irq, IRQ_NOAUTOEN);
+
+	ret = devm_request_threaded_irq(dev, stm32_pcie->perst_irq, NULL,
+					stm32_pcie_ep_perst_irq_thread,
+					IRQF_TRIGGER_RISING |
+					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+					"perst_irq", stm32_pcie);
+	if (ret) {
+		dev_err(dev, "Failed to request PERST IRQ: %d\n", ret);
+		return ret;
+	}
+
+	return stm32_add_pcie_ep(stm32_pcie, pdev);
+}
+
+static void stm32_pcie_remove(struct platform_device *pdev)
+{
+	struct stm32_pcie *stm32_pcie = platform_get_drvdata(pdev);
+	struct dw_pcie_ep *ep = &stm32_pcie->pci->ep;
+
+	disable_irq(stm32_pcie->perst_irq);
+
+	dw_pcie_ep_deinit(ep);
+
+	stm32_pcie_disable_resources(stm32_pcie);
+
+	pm_runtime_put_sync(&pdev->dev);
+}
+
+static const struct of_device_id stm32_pcie_ep_of_match[] = {
+	{ .compatible = "st,stm32mp25-pcie-ep" },
+	{},
+};
+
+static struct platform_driver stm32_pcie_ep_driver = {
+	.probe = stm32_pcie_probe,
+	.remove = stm32_pcie_remove,
+	.driver = {
+		.name = "stm32-ep-pcie",
+		.of_match_table = stm32_pcie_ep_of_match,
+	},
+};
+
+module_platform_driver(stm32_pcie_ep_driver);
+
+MODULE_AUTHOR("Christian Bruel <christian.bruel@foss.st.com>");
+MODULE_DESCRIPTION("STM32MP25 PCIe Endpoint Controller driver");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(of, stm32_pcie_ep_of_match);
diff --git a/drivers/pci/controller/dwc/pcie-stm32.h b/drivers/pci/controller/dwc/pcie-stm32.h
index 3efd00937d3d..ac0955adf150 100644
--- a/drivers/pci/controller/dwc/pcie-stm32.h
+++ b/drivers/pci/controller/dwc/pcie-stm32.h
@@ -9,7 +9,9 @@
 #define to_stm32_pcie(x)	dev_get_drvdata((x)->dev)
 
 #define STM32MP25_PCIECR_TYPE_MASK	GENMASK(11, 8)
+#define STM32MP25_PCIECR_EP		0
 #define STM32MP25_PCIECR_LTSSM_EN	BIT(2)
+#define STM32MP25_PCIECR_REQ_RETRY_EN	BIT(3)
 #define STM32MP25_PCIECR_RC		BIT(10)
 
 #define SYSCFG_PCIECR			0x6000
-- 
2.34.1

[PATCH v2 5/5] MAINTAINERS: add entry for ST STM32MP25 PCIe drivers

[Christian Bruel]

Add myself as maintainer of STM32MP25 PCIe host and PCIe endpoint drivers

Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
---
 MAINTAINERS | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 4803908768e8..277e1cc0769e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17912,6 +17912,13 @@ L:	linux-samsung-soc@vger.kernel.org
 S:	Maintained
 F:	drivers/pci/controller/dwc/pci-exynos.c
 
+PCI DRIVER FOR STM32MP25
+M:	Christian Bruel <christian.bruel@foss.st.com>
+L:	linux-pci@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/pci/st,stm32-pcie-*.yaml
+F:	drivers/pci/controller/dwc/*stm32*
+
 PCI DRIVER FOR SYNOPSYS DESIGNWARE
 M:	Jingoo Han <jingoohan1@gmail.com>
 M:	Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
-- 
2.34.1

Re: [PATCH v2 1/5] dt-bindings: PCI: Add STM32MP25 PCIe root complex bindings

[Rob Herring]

On Tue, Nov 26, 2024 at 04:51:15PM +0100, Christian Bruel wrote:
> Document the bindings for STM32MP25 PCIe Controller configured in
> root complex mode.
> 
> Supports 4 legacy interrupts and MSI interrupts from the ARM
> GICv2m controller.
> 
> STM32 PCIe may be in a power domain which is the case for the STM32MP25
> based boards.
> 
> Supports wake# from wake-gpios
> 
> Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
> ---
>  .../bindings/pci/st,stm32-pcie-common.yaml    | 45 +++++++++
>  .../bindings/pci/st,stm32-pcie-host.yaml      | 99 +++++++++++++++++++
>  2 files changed, 144 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml
>  create mode 100644 Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml
> 
> diff --git a/Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml b/Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml
> new file mode 100644
> index 000000000000..479c03134da3
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml
> @@ -0,0 +1,45 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/pci/st,stm32-pcie-common.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: STM32MP25 PCIe RC/EP controller
> +
> +maintainers:
> +  - Christian Bruel <christian.bruel@foss.st.com>
> +
> +description:
> +  STM32MP25 PCIe RC/EP common properties
> +
> +properties:
> +  clocks:
> +    maxItems: 1
> +    description: PCIe system clock
> +
> +  resets:
> +    maxItems: 1
> +
> +  phys:
> +    maxItems: 1
> +
> +  phy-names:
> +    const: pcie-phy
> +
> +  power-domains:
> +    maxItems: 1
> +
> +  access-controllers:
> +    maxItems: 1
> +
> +  reset-gpios:
> +    description: GPIO controlled connection to PERST# signal
> +    maxItems: 1
> +
> +required:
> +  - clocks
> +  - resets
> +  - phys
> +  - phy-names
> +
> +additionalProperties: true
> diff --git a/Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml b/Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml
> new file mode 100644
> index 000000000000..18083cc69024
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml
> @@ -0,0 +1,99 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/pci/st,stm32-pcie-host.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: STM32MP25 PCIe root complex driver
> +
> +maintainers:
> +  - Christian Bruel <christian.bruel@foss.st.com>
> +
> +description:
> +  PCIe root complex controller based on the Synopsys DesignWare PCIe core.
> +
> +allOf:
> +  - $ref: /schemas/pci/snps,dw-pcie.yaml#
> +  - $ref: /schemas/pci/st,stm32-pcie-common.yaml#
> +
> +select:

You don't need select.

> +  properties:
> +    compatible:
> +      const: st,stm32mp25-pcie-rc
> +  required:
> +    - compatible
> +
> +properties:
> +  compatible:
> +    const: st,stm32mp25-pcie-rc
> +
> +  reg:
> +    items:
> +      - description: Data Bus Interface (DBI) registers.
> +      - description: PCIe configuration registers.
> +
> +  reg-names:
> +    items:
> +      - const: dbi
> +      - const: config
> +
> +  num-lanes:
> +    const: 1

Not required, so what's the default? If it can only ever be 1, then why 
do you need the property?

> +
> +  msi-parent:
> +    maxItems: 1
> +
> +  wake-gpios:
> +    description: GPIO controlled connection to WAKE# input signal
> +    maxItems: 1
> +
> +  wakeup-source: true
> +
> +dependentRequired:
> +  wakeup-source: [ wake-gpios ]
> +
> +required:
> +  - interrupt-map
> +  - interrupt-map-mask
> +  - ranges
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/st,stm32mp25-rcc.h>
> +    #include <dt-bindings/gpio/gpio.h>
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +    #include <dt-bindings/phy/phy.h>
> +    #include <dt-bindings/reset/st,stm32mp25-rcc.h>
> +
> +    pcie@48400000 {
> +        compatible = "st,stm32mp25-pcie-rc";
> +        device_type = "pci";
> +        num-lanes = <1>;
> +        reg = <0x48400000 0x400000>,
> +              <0x10000000 0x10000>;
> +        reg-names = "dbi", "config";
> +        #interrupt-cells = <1>;
> +        interrupt-map-mask = <0 0 0 7>;
> +        interrupt-map = <0 0 0 1 &intc 0 0 GIC_SPI 264 IRQ_TYPE_LEVEL_HIGH>,
> +                        <0 0 0 2 &intc 0 0 GIC_SPI 265 IRQ_TYPE_LEVEL_HIGH>,
> +                        <0 0 0 3 &intc 0 0 GIC_SPI 266 IRQ_TYPE_LEVEL_HIGH>,
> +                        <0 0 0 4 &intc 0 0 GIC_SPI 267 IRQ_TYPE_LEVEL_HIGH>;
> +        #address-cells = <3>;
> +        #size-cells = <2>;
> +        ranges = <0x01000000 0 0x10010000 0x10010000 0 0x10000>,
> +                 <0x02000000 0 0x10020000 0x10020000 0 0x7fe0000>,
> +                 <0x42000000 0 0x18000000 0x18000000 0 0x8000000>;
> +        clocks = <&rcc CK_BUS_PCIE>;
> +        phys = <&combophy PHY_TYPE_PCIE>;
> +        phy-names = "pcie-phy";
> +        resets = <&rcc PCIE_R>;
> +        msi-parent = <&v2m0>;
> +        wakeup-source;
> +        wake-gpios = <&gpioh 5 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
> +        reset-gpios = <&gpioj 8 GPIO_ACTIVE_LOW>;
> +        access-controllers = <&rifsc 68>;
> +        power-domains = <&CLUSTER_PD>;
> +    };
> +
> -- 
> 2.34.1
> 

Re: [PATCH v2 3/5] dt-bindings: PCI: Add STM32MP25 PCIe endpoint bindings

[Rob Herring]

On Tue, Nov 26, 2024 at 04:51:17PM +0100, Christian Bruel wrote:
> STM32MP25 PCIe Controller is based on the DesignWare core configured as
> end point mode from the SYSCFG register.
> 
> Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
> ---
>  .../bindings/pci/st,stm32-pcie-ep.yaml        | 61 +++++++++++++++++++
>  1 file changed, 61 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pci/st,stm32-pcie-ep.yaml
> 
> diff --git a/Documentation/devicetree/bindings/pci/st,stm32-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/st,stm32-pcie-ep.yaml
> new file mode 100644
> index 000000000000..0da3ee012ba8
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pci/st,stm32-pcie-ep.yaml
> @@ -0,0 +1,61 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/pci/st,stm32-pcie-ep.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: STM32MP25 PCIe endpoint driver

Bindings are not a driver. Otherwise,

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>

Re: [PATCH v2 3/5] dt-bindings: PCI: Add STM32MP25 PCIe endpoint bindings

[Rob Herring (Arm)]

On Tue, 26 Nov 2024 16:51:17 +0100, Christian Bruel wrote:
> STM32MP25 PCIe Controller is based on the DesignWare core configured as
> end point mode from the SYSCFG register.
> 
> Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
> ---
>  .../bindings/pci/st,stm32-pcie-ep.yaml        | 61 +++++++++++++++++++
>  1 file changed, 61 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pci/st,stm32-pcie-ep.yaml
> 

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>

Re: [PATCH v2 2/5] PCI: stm32: Add PCIe host support for STM32MP25

[Bjorn Helgaas]

[+to Rob, DMA mask question]

On Tue, Nov 26, 2024 at 04:51:16PM +0100, Christian Bruel wrote:
> Add driver for the STM32MP25 SoC PCIe Gen2 controller based on the
> DesignWare PCIe core.

Can you include the numeric rate, not just "gen2", so we don't have to
search for it?

> +static int stm32_pcie_resume_noirq(struct device *dev)
> +{
> +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
> +	struct dw_pcie *pci = stm32_pcie->pci;
> +	struct dw_pcie_rp *pp = &pci->pp;
> +	int ret;
> +
> +	/* init_state must be called first to force clk_req# gpio when no
> +	 * device is plugged.
> +	 */

Use drivers/pci/ conventional comment style:

  /*
   * text ...
   */

> +static bool is_stm32_pcie_driver(struct device *dev)
> +{
> +	/* PCI bridge */
> +	dev = get_device(dev);
> +
> +	/* Platform driver */
> +	dev = get_device(dev->parent);
> +
> +	return (dev->driver == &stm32_pcie_driver.driver);
> +}
> +
> +/*
> + * DMA masters can only access the first 4GB of memory space,
> + * so we setup the bus DMA limit accordingly.
> + */
> +static int stm32_dma_limit(struct pci_dev *pdev, void *data)
> +{
> +	dev_dbg(&pdev->dev, "disabling DMA DAC for device");
> +
> +	pdev->dev.bus_dma_limit = DMA_BIT_MASK(32);

I don't think this is the right way to do this.  Surely there's a way
to describe the DMA capability of the bridge once instead of iterating
over all the downstream devices?  This quirk can't work for hot-added
devices anyway.

> +	return 0;
> +}
> +
> +static void quirk_stm32_dma_mask(struct pci_dev *pci)
> +{
> +	struct pci_dev *root_port;
> +
> +	root_port = pcie_find_root_port(pci);
> +
> +	if (root_port && is_stm32_pcie_driver(root_port->dev.parent))
> +		pci_walk_bus(pci->bus, stm32_dma_limit, NULL);
> +}
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SYNOPSYS, 0x0550, quirk_stm32_dma_mask);

Re: [PATCH v2 2/5] PCI: stm32: Add PCIe host support for STM32MP25

[Lucas Stach]

Am Freitag, dem 29.11.2024 um 14:58 -0600 schrieb Bjorn Helgaas:
> [+to Rob, DMA mask question]
> 
> On Tue, Nov 26, 2024 at 04:51:16PM +0100, Christian Bruel wrote:
> > Add driver for the STM32MP25 SoC PCIe Gen2 controller based on the
> > DesignWare PCIe core.
> 
> Can you include the numeric rate, not just "gen2", so we don't have to
> search for it?
> 
> > +static int stm32_pcie_resume_noirq(struct device *dev)
> > +{
> > +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
> > +	struct dw_pcie *pci = stm32_pcie->pci;
> > +	struct dw_pcie_rp *pp = &pci->pp;
> > +	int ret;
> > +
> > +	/* init_state must be called first to force clk_req# gpio when no
> > +	 * device is plugged.
> > +	 */
> 
> Use drivers/pci/ conventional comment style:
> 
>   /*
>    * text ...
>    */
> 
> > +static bool is_stm32_pcie_driver(struct device *dev)
> > +{
> > +	/* PCI bridge */
> > +	dev = get_device(dev);
> > +
> > +	/* Platform driver */
> > +	dev = get_device(dev->parent);
> > +
> > +	return (dev->driver == &stm32_pcie_driver.driver);
> > +}
> > +
> > +/*
> > + * DMA masters can only access the first 4GB of memory space,
> > + * so we setup the bus DMA limit accordingly.
> > + */
> > +static int stm32_dma_limit(struct pci_dev *pdev, void *data)
> > +{
> > +	dev_dbg(&pdev->dev, "disabling DMA DAC for device");
> > +
> > +	pdev->dev.bus_dma_limit = DMA_BIT_MASK(32);
> 
> I don't think this is the right way to do this.  Surely there's a way
> to describe the DMA capability of the bridge once instead of iterating
> over all the downstream devices?  This quirk can't work for hot-added
> devices anyway.
> 
This should simply be a dma-ranges property in the PCIe host controller
DT node, which should describe the DMA address range limits for
transactions passing through the host.

Regards,
Lucas

> > +	return 0;
> > +}
> > +
> > +static void quirk_stm32_dma_mask(struct pci_dev *pci)
> > +{
> > +	struct pci_dev *root_port;
> > +
> > +	root_port = pcie_find_root_port(pci);
> > +
> > +	if (root_port && is_stm32_pcie_driver(root_port->dev.parent))
> > +		pci_walk_bus(pci->bus, stm32_dma_limit, NULL);
> > +}
> > +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SYNOPSYS, 0x0550, quirk_stm32_dma_mask);
> 

Re: [PATCH v2 1/5] dt-bindings: PCI: Add STM32MP25 PCIe root complex bindings

[Manivannan Sadhasivam]

On Tue, Nov 26, 2024 at 04:51:15PM +0100, Christian Bruel wrote:
> Document the bindings for STM32MP25 PCIe Controller configured in
> root complex mode.
> 
> Supports 4 legacy interrupts and MSI interrupts from the ARM
> GICv2m controller.
> 
> STM32 PCIe may be in a power domain which is the case for the STM32MP25
> based boards.
> 
> Supports wake# from wake-gpios
> 
> Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
> ---
>  .../bindings/pci/st,stm32-pcie-common.yaml    | 45 +++++++++
>  .../bindings/pci/st,stm32-pcie-host.yaml      | 99 +++++++++++++++++++
>  2 files changed, 144 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml
>  create mode 100644 Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml
> 
> diff --git a/Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml b/Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml
> new file mode 100644
> index 000000000000..479c03134da3
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml
> @@ -0,0 +1,45 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/pci/st,stm32-pcie-common.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: STM32MP25 PCIe RC/EP controller
> +
> +maintainers:
> +  - Christian Bruel <christian.bruel@foss.st.com>
> +
> +description:
> +  STM32MP25 PCIe RC/EP common properties
> +
> +properties:
> +  clocks:
> +    maxItems: 1
> +    description: PCIe system clock
> +
> +  resets:
> +    maxItems: 1
> +
> +  phys:
> +    maxItems: 1
> +
> +  phy-names:
> +    const: pcie-phy
> +
> +  power-domains:
> +    maxItems: 1
> +
> +  access-controllers:
> +    maxItems: 1
> +
> +  reset-gpios:
> +    description: GPIO controlled connection to PERST# signal
> +    maxItems: 1
> +
> +required:
> +  - clocks
> +  - resets
> +  - phys
> +  - phy-names
> +
> +additionalProperties: true
> diff --git a/Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml b/Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml
> new file mode 100644
> index 000000000000..18083cc69024
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml
> @@ -0,0 +1,99 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/pci/st,stm32-pcie-host.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: STM32MP25 PCIe root complex driver
> +
> +maintainers:
> +  - Christian Bruel <christian.bruel@foss.st.com>
> +
> +description:
> +  PCIe root complex controller based on the Synopsys DesignWare PCIe core.
> +
> +allOf:
> +  - $ref: /schemas/pci/snps,dw-pcie.yaml#
> +  - $ref: /schemas/pci/st,stm32-pcie-common.yaml#
> +
> +select:
> +  properties:
> +    compatible:
> +      const: st,stm32mp25-pcie-rc
> +  required:
> +    - compatible
> +
> +properties:
> +  compatible:
> +    const: st,stm32mp25-pcie-rc
> +
> +  reg:
> +    items:
> +      - description: Data Bus Interface (DBI) registers.
> +      - description: PCIe configuration registers.
> +
> +  reg-names:
> +    items:
> +      - const: dbi
> +      - const: config
> +
> +  num-lanes:
> +    const: 1
> +
> +  msi-parent:
> +    maxItems: 1
> +
> +  wake-gpios:
> +    description: GPIO controlled connection to WAKE# input signal
> +    maxItems: 1
> +
> +  wakeup-source: true
> +
> +dependentRequired:
> +  wakeup-source: [ wake-gpios ]
> +
> +required:
> +  - interrupt-map
> +  - interrupt-map-mask
> +  - ranges
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/st,stm32mp25-rcc.h>
> +    #include <dt-bindings/gpio/gpio.h>
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +    #include <dt-bindings/phy/phy.h>
> +    #include <dt-bindings/reset/st,stm32mp25-rcc.h>
> +
> +    pcie@48400000 {
> +        compatible = "st,stm32mp25-pcie-rc";
> +        device_type = "pci";
> +        num-lanes = <1>;
> +        reg = <0x48400000 0x400000>,
> +              <0x10000000 0x10000>;
> +        reg-names = "dbi", "config";
> +        #interrupt-cells = <1>;
> +        interrupt-map-mask = <0 0 0 7>;
> +        interrupt-map = <0 0 0 1 &intc 0 0 GIC_SPI 264 IRQ_TYPE_LEVEL_HIGH>,
> +                        <0 0 0 2 &intc 0 0 GIC_SPI 265 IRQ_TYPE_LEVEL_HIGH>,
> +                        <0 0 0 3 &intc 0 0 GIC_SPI 266 IRQ_TYPE_LEVEL_HIGH>,
> +                        <0 0 0 4 &intc 0 0 GIC_SPI 267 IRQ_TYPE_LEVEL_HIGH>;
> +        #address-cells = <3>;
> +        #size-cells = <2>;
> +        ranges = <0x01000000 0 0x10010000 0x10010000 0 0x10000>,

PCI address of I/O region should start from address 0x00000000.

Also use hex notation for all values.

- Mani

-- 
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Re: [PATCH v2 2/5] PCI: stm32: Add PCIe host support for STM32MP25

[Manivannan Sadhasivam]

On Tue, Nov 26, 2024 at 04:51:16PM +0100, Christian Bruel wrote:
> Add driver for the STM32MP25 SoC PCIe Gen2 controller based on the
> DesignWare PCIe core.
> 
> Supports MSI via GICv2m, Single Virtual Channel, Single Function
> 
> Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
> ---
>  drivers/pci/controller/dwc/Kconfig      |  12 +
>  drivers/pci/controller/dwc/Makefile     |   1 +
>  drivers/pci/controller/dwc/pcie-stm32.c | 402 ++++++++++++++++++++++++
>  drivers/pci/controller/dwc/pcie-stm32.h |  15 +
>  4 files changed, 430 insertions(+)
>  create mode 100644 drivers/pci/controller/dwc/pcie-stm32.c
>  create mode 100644 drivers/pci/controller/dwc/pcie-stm32.h
> 
> diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
> index b6d6778b0698..0c18879b604c 100644
> --- a/drivers/pci/controller/dwc/Kconfig
> +++ b/drivers/pci/controller/dwc/Kconfig
> @@ -389,6 +389,18 @@ config PCIE_SPEAR13XX
>  	help
>  	  Say Y here if you want PCIe support on SPEAr13XX SoCs.
>  
> +config PCIE_STM32
> +	tristate "STMicroelectronics STM32MP25 PCIe Controller (host mode)"
> +	depends on ARCH_STM32 || COMPILE_TEST
> +	depends on PCI_MSI
> +	select PCIE_DW_HOST
> +	help
> +	  Enables support for the DesignWare core based PCIe host controller
> +	  found in STM32MP25 SoC.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called pcie-stm32.
> +
>  config PCI_DRA7XX
>  	tristate
>  
> diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
> index a8308d9ea986..576d99cb3bc5 100644
> --- a/drivers/pci/controller/dwc/Makefile
> +++ b/drivers/pci/controller/dwc/Makefile
> @@ -28,6 +28,7 @@ obj-$(CONFIG_PCIE_UNIPHIER) += pcie-uniphier.o
>  obj-$(CONFIG_PCIE_UNIPHIER_EP) += pcie-uniphier-ep.o
>  obj-$(CONFIG_PCIE_VISCONTI_HOST) += pcie-visconti.o
>  obj-$(CONFIG_PCIE_RCAR_GEN4) += pcie-rcar-gen4.o
> +obj-$(CONFIG_PCIE_STM32) += pcie-stm32.o
>  
>  # The following drivers are for devices that use the generic ACPI
>  # pci_root.c driver but don't support standard ECAM config access.
> diff --git a/drivers/pci/controller/dwc/pcie-stm32.c b/drivers/pci/controller/dwc/pcie-stm32.c
> new file mode 100644
> index 000000000000..fa787406c0e4
> --- /dev/null
> +++ b/drivers/pci/controller/dwc/pcie-stm32.c
> @@ -0,0 +1,402 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * STMicroelectronics STM32MP25 PCIe root complex driver.
> + *
> + * Copyright (C) 2024 STMicroelectronics
> + * Author: Christian Bruel <christian.bruel@foss.st.com>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/of_platform.h>
> +#include <linux/phy/phy.h>
> +#include <linux/pinctrl/devinfo.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/reset.h>
> +#include "pcie-designware.h"
> +#include "pcie-stm32.h"
> +#include "../../pci.h"
> +
> +struct stm32_pcie {
> +	struct dw_pcie *pci;
> +	struct regmap *regmap;
> +	struct reset_control *rst;
> +	struct phy *phy;
> +	struct clk *clk;
> +	struct gpio_desc *perst_gpio;
> +	struct gpio_desc *wake_gpio;
> +	unsigned int wake_irq;
> +	bool link_is_up;
> +};
> +
> +static int stm32_pcie_start_link(struct dw_pcie *pci)
> +{
> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
> +	u32 ret;
> +
> +	if (stm32_pcie->perst_gpio) {

gpiod_set_value() will bail out if 'perst_gpio' is NULL. So no need to add a
check.

> +		/* Make sure PERST# is asserted. */

Why?

> +		gpiod_set_value(stm32_pcie->perst_gpio, 1);
> +
> +		fsleep(PCIE_T_PERST_CLK_US);
> +		gpiod_set_value(stm32_pcie->perst_gpio, 0);

Why can't you deassert PERST# in stm32_add_pcie_port()?

> +	}
> +
> +	ret = regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
> +				 STM32MP25_PCIECR_LTSSM_EN,
> +				 STM32MP25_PCIECR_LTSSM_EN);
> +
> +	if (stm32_pcie->perst_gpio)

It doesn't hurt to call msleep() always.

> +		msleep(PCIE_T_RRS_READY_MS);
> +
> +	return ret;
> +}
> +
> +static void stm32_pcie_stop_link(struct dw_pcie *pci)
> +{
> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
> +
> +	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
> +			   STM32MP25_PCIECR_LTSSM_EN, 0);
> +
> +	/* Assert PERST# */
> +	if (stm32_pcie->perst_gpio)
> +		gpiod_set_value(stm32_pcie->perst_gpio, 1);

I don't like tying PERST# handling with start/stop link. PERST# should be
handled based on the power/clock state.

> +}
> +
> +static int stm32_pcie_suspend(struct device *dev)
> +{
> +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
> +
> +	if (device_may_wakeup(dev) || device_wakeup_path(dev))
> +		enable_irq_wake(stm32_pcie->wake_irq);
> +
> +	return 0;
> +}
> +
> +static int stm32_pcie_resume(struct device *dev)
> +{
> +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
> +
> +	if (device_may_wakeup(dev) || device_wakeup_path(dev))
> +		disable_irq_wake(stm32_pcie->wake_irq);
> +
> +	return 0;
> +}
> +
> +static int stm32_pcie_suspend_noirq(struct device *dev)
> +{
> +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
> +
> +	stm32_pcie->link_is_up = dw_pcie_link_up(stm32_pcie->pci);
> +
> +	stm32_pcie_stop_link(stm32_pcie->pci);

I don't understand how endpoint can wakeup the host if PERST# gets asserted.

> +	clk_disable_unprepare(stm32_pcie->clk);
> +
> +	if (!device_may_wakeup(dev) && !device_wakeup_path(dev))
> +		phy_exit(stm32_pcie->phy);
> +
> +	return pinctrl_pm_select_sleep_state(dev);
> +}
> +
> +static int stm32_pcie_resume_noirq(struct device *dev)
> +{
> +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
> +	struct dw_pcie *pci = stm32_pcie->pci;
> +	struct dw_pcie_rp *pp = &pci->pp;
> +	int ret;
> +
> +	/* init_state must be called first to force clk_req# gpio when no

CLKREQ#

Why RC should control CLKREQ#?

Also please use preferred style for multi-line comments:

	/*
	 * ...
	 */

> +	 * device is plugged.
> +	 */
> +	if (!IS_ERR(dev->pins->init_state))
> +		ret = pinctrl_select_state(dev->pins->p, dev->pins->init_state);
> +	else
> +		ret = pinctrl_pm_select_default_state(dev);
> +
> +	if (ret) {
> +		dev_err(dev, "Failed to activate pinctrl pm state: %d\n", ret);
> +		return ret;
> +	}
> +
> +	if (!device_may_wakeup(dev) && !device_wakeup_path(dev)) {
> +		ret = phy_init(stm32_pcie->phy);
> +		if (ret) {
> +			pinctrl_pm_select_default_state(dev);
> +			return ret;
> +		}
> +	}
> +
> +	ret = clk_prepare_enable(stm32_pcie->clk);
> +	if (ret)
> +		goto clk_err;

Please name the goto labels of their purpose. Like err_phy_exit.

> +
> +	ret = dw_pcie_setup_rc(pp);
> +	if (ret)
> +		goto pcie_err;

This should be, 'err_disable_clk'.

> +
> +	if (stm32_pcie->link_is_up) {

Why do you need this check? You cannot start the link in the absence of an
endpoint?

> +		ret = stm32_pcie_start_link(stm32_pcie->pci);
> +		if (ret)
> +			goto pcie_err;
> +
> +		/* Ignore errors, the link may come up later */
> +		dw_pcie_wait_for_link(stm32_pcie->pci);
> +	}
> +
> +	pinctrl_pm_select_default_state(dev);
> +
> +	return 0;
> +
> +pcie_err:
> +	dw_pcie_host_deinit(pp);
> +	clk_disable_unprepare(stm32_pcie->clk);
> +clk_err:
> +	phy_exit(stm32_pcie->phy);
> +	pinctrl_pm_select_default_state(dev);
> +
> +	return ret;
> +}
> +
> +static const struct dev_pm_ops stm32_pcie_pm_ops = {
> +	NOIRQ_SYSTEM_SLEEP_PM_OPS(stm32_pcie_suspend_noirq,
> +				  stm32_pcie_resume_noirq)

Can you make use of dw_pcie_{suspend/resume}_noirq() APIs?

> +	SYSTEM_SLEEP_PM_OPS(stm32_pcie_suspend, stm32_pcie_resume)
> +};
> +
> +static const struct dw_pcie_host_ops stm32_pcie_host_ops = {
> +};
> +
> +static const struct dw_pcie_ops dw_pcie_ops = {
> +	.start_link = stm32_pcie_start_link,
> +	.stop_link = stm32_pcie_stop_link
> +};
> +

[...]

> +	if (device_property_read_bool(dev, "wakeup-source")) {
> +		stm32_pcie->wake_gpio = devm_gpiod_get_optional(dev, "wake",
> +								GPIOD_IN);
> +		if (IS_ERR(stm32_pcie->wake_gpio))
> +			return dev_err_probe(dev, PTR_ERR(stm32_pcie->wake_gpio),
> +					     "Failed to get wake GPIO\n");
> +	}
> +
> +	if (stm32_pcie->wake_gpio) {
> +		stm32_pcie->wake_irq = gpiod_to_irq(stm32_pcie->wake_gpio);
> +
> +		ret = devm_request_threaded_irq(&pdev->dev,
> +						stm32_pcie->wake_irq, NULL,
> +						stm32_pcie_wake_irq_handler,
> +						IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> +						"wake_irq", stm32_pcie);
> +
> +		if (ret)
> +			return dev_err_probe(dev, ret, "Failed to request WAKE IRQ: %d\n", ret);
> +	}

Can we move WAKE# gpio handling to DWC core? There is nothing STM32 specific
here.

> +
> +	ret = devm_pm_runtime_enable(dev);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to enable runtime PM %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = pm_runtime_resume_and_get(dev);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to get runtime PM %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = stm32_add_pcie_port(stm32_pcie, pdev);
> +	if (ret)  {
> +		pm_runtime_put_sync(&pdev->dev);
> +		return ret;
> +	}
> +
> +	if (stm32_pcie->wake_gpio)
> +		device_set_wakeup_capable(dev, true);
> +
> +	return 0;
> +}
> +
> +static void stm32_pcie_remove(struct platform_device *pdev)
> +{
> +	struct stm32_pcie *stm32_pcie = platform_get_drvdata(pdev);
> +	struct dw_pcie_rp *pp = &stm32_pcie->pci->pp;
> +
> +	if (stm32_pcie->wake_gpio)
> +		device_init_wakeup(&pdev->dev, false);
> +
> +	dw_pcie_host_deinit(pp);
> +	clk_disable_unprepare(stm32_pcie->clk);
> +
> +	phy_exit(stm32_pcie->phy);
> +
> +	pm_runtime_put_sync(&pdev->dev);
> +}
> +
> +static const struct of_device_id stm32_pcie_of_match[] = {
> +	{ .compatible = "st,stm32mp25-pcie-rc" },
> +	{},
> +};
> +
> +static struct platform_driver stm32_pcie_driver = {
> +	.probe = stm32_pcie_probe,
> +	.remove = stm32_pcie_remove,
> +	.driver = {
> +		.name = "stm32-pcie",
> +		.of_match_table = stm32_pcie_of_match,
> +		.pm		= &stm32_pcie_pm_ops,

Just use a single space instead of tab.

Could you also set PROBE_PREFER_ASYNCHRONOUS to allow async probing of
controller drivers?

> +	},
> +};
> +
> +static bool is_stm32_pcie_driver(struct device *dev)
> +{
> +	/* PCI bridge */
> +	dev = get_device(dev);
> +
> +	/* Platform driver */
> +	dev = get_device(dev->parent);
> +
> +	return (dev->driver == &stm32_pcie_driver.driver);
> +}
> +
> +/*
> + * DMA masters can only access the first 4GB of memory space,
> + * so we setup the bus DMA limit accordingly.
> + */
> +static int stm32_dma_limit(struct pci_dev *pdev, void *data)
> +{
> +	dev_dbg(&pdev->dev, "disabling DMA DAC for device");
> +
> +	pdev->dev.bus_dma_limit = DMA_BIT_MASK(32);
> +
> +	return 0;
> +}
> +
> +static void quirk_stm32_dma_mask(struct pci_dev *pci)
> +{
> +	struct pci_dev *root_port;
> +
> +	root_port = pcie_find_root_port(pci);
> +
> +	if (root_port && is_stm32_pcie_driver(root_port->dev.parent))
> +		pci_walk_bus(pci->bus, stm32_dma_limit, NULL);
> +}
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SYNOPSYS, 0x0550, quirk_stm32_dma_mask);

This is not the correct way of using DMA masks as Bjorn noted.

- Mani

-- 
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Re: [PATCH v2 3/5] dt-bindings: PCI: Add STM32MP25 PCIe endpoint bindings

[Manivannan Sadhasivam]

On Tue, Nov 26, 2024 at 04:51:17PM +0100, Christian Bruel wrote:
> STM32MP25 PCIe Controller is based on the DesignWare core configured as
> end point mode from the SYSCFG register.
> 
> Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>

Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

- Mani

> ---
>  .../bindings/pci/st,stm32-pcie-ep.yaml        | 61 +++++++++++++++++++
>  1 file changed, 61 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pci/st,stm32-pcie-ep.yaml
> 
> diff --git a/Documentation/devicetree/bindings/pci/st,stm32-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/st,stm32-pcie-ep.yaml
> new file mode 100644
> index 000000000000..0da3ee012ba8
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pci/st,stm32-pcie-ep.yaml
> @@ -0,0 +1,61 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/pci/st,stm32-pcie-ep.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: STM32MP25 PCIe endpoint driver
> +
> +maintainers:
> +  - Christian Bruel <christian.bruel@foss.st.com>
> +
> +description:
> +  PCIe endpoint controller based on the Synopsys DesignWare PCIe core.
> +
> +allOf:
> +  - $ref: /schemas/pci/snps,dw-pcie-ep.yaml#
> +  - $ref: /schemas/pci/st,stm32-pcie-common.yaml#
> +
> +properties:
> +  compatible:
> +    const: st,stm32mp25-pcie-ep
> +
> +  reg:
> +    items:
> +      - description: Data Bus Interface (DBI) registers.
> +      - description: PCIe configuration registers.
> +
> +  reg-names:
> +    items:
> +      - const: dbi
> +      - const: addr_space
> +
> +required:
> +  - reset-gpios
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/st,stm32mp25-rcc.h>
> +    #include <dt-bindings/gpio/gpio.h>
> +    #include <dt-bindings/phy/phy.h>
> +    #include <dt-bindings/reset/st,stm32mp25-rcc.h>
> +
> +    pcie-ep@48400000 {
> +        compatible = "st,stm32mp25-pcie-ep";
> +        num-lanes = <1>;
> +        reg = <0x48400000 0x400000>,
> +              <0x10000000 0x8000000>;
> +        reg-names = "dbi", "addr_space";
> +        clocks = <&rcc CK_BUS_PCIE>;
> +        phys = <&combophy PHY_TYPE_PCIE>;
> +        phy-names = "pcie-phy";
> +        resets = <&rcc PCIE_R>;
> +        pinctrl-names = "default", "init";
> +        pinctrl-0 = <&pcie_pins_a>;
> +        pinctrl-1 = <&pcie_init_pins_a>;
> +        reset-gpios = <&gpioj 8 GPIO_ACTIVE_LOW>;
> +        access-controllers = <&rifsc 68>;
> +        power-domains = <&CLUSTER_PD>;
> +    };
> -- 
> 2.34.1
> 

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 4/5] PCI: stm32: Add PCIe endpoint support for STM32MP25

[Manivannan Sadhasivam]

On Tue, Nov 26, 2024 at 04:51:18PM +0100, Christian Bruel wrote:

[...]

> +static int stm32_pcie_start_link(struct dw_pcie *pci)
> +{
> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
> +	int ret;
> +
> +	if (stm32_pcie->link_status == STM32_PCIE_EP_LINK_ENABLED) {
> +		dev_dbg(pci->dev, "Link is already enabled\n");
> +		return 0;
> +	}
> +
> +	ret = stm32_pcie_enable_link(pci);
> +	if (ret) {
> +		dev_err(pci->dev, "PCIe cannot establish link: %d\n", ret);
> +		return ret;
> +	}

How the REFCLK is supplied to the endpoint? From host or generated locally?

> +
> +	stm32_pcie->link_status = STM32_PCIE_EP_LINK_ENABLED;
> +
> +	enable_irq(stm32_pcie->perst_irq);
> +
> +	return 0;
> +}
> +
> +static void stm32_pcie_stop_link(struct dw_pcie *pci)
> +{
> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
> +
> +	if (stm32_pcie->link_status == STM32_PCIE_EP_LINK_DISABLED) {
> +		dev_dbg(pci->dev, "Link is already disabled\n");
> +		return;
> +	}
> +
> +	disable_irq(stm32_pcie->perst_irq);
> +
> +	stm32_pcie_disable_link(pci);
> +
> +	stm32_pcie->link_status = STM32_PCIE_EP_LINK_DISABLED;
> +}
> +
> +static int stm32_pcie_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
> +				unsigned int type, u16 interrupt_num)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> +
> +	switch (type) {
> +	case PCI_IRQ_INTX:
> +		return dw_pcie_ep_raise_intx_irq(ep, func_no);
> +	case PCI_IRQ_MSI:
> +		return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
> +	default:
> +		dev_err(pci->dev, "UNKNOWN IRQ type\n");
> +		return -EINVAL;
> +	}
> +}
> +
> +static const struct pci_epc_features stm32_pcie_epc_features = {
> +	.msi_capable = true,
> +	.align = 1 << 16,

Use SZ_64K

> +};
> +

[...]

> +static int stm32_add_pcie_ep(struct stm32_pcie *stm32_pcie,
> +			     struct platform_device *pdev)
> +{
> +	struct dw_pcie *pci = stm32_pcie->pci;
> +	struct dw_pcie_ep *ep = &pci->ep;
> +	struct device *dev = &pdev->dev;
> +	int ret;
> +
> +	ret = regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
> +				 STM32MP25_PCIECR_TYPE_MASK,
> +				 STM32MP25_PCIECR_EP);
> +	if (ret)
> +		return ret;
> +
> +	ret = pm_runtime_resume_and_get(dev);
> +	if (ret < 0) {
> +		dev_err(dev, "pm runtime resume failed: %d\n", ret);
> +		return ret;
> +	}

You might want to do runtime resume before accessing regmap.

> +
> +	reset_control_assert(stm32_pcie->rst);
> +	reset_control_deassert(stm32_pcie->rst);
> +
> +	ep->ops = &stm32_pcie_ep_ops;
> +
> +	ret = dw_pcie_ep_init(ep);
> +	if (ret) {
> +		dev_err(dev, "failed to initialize ep: %d\n", ret);
> +		goto err_init;
> +	}
> +
> +	ret = stm32_pcie_enable_resources(stm32_pcie);
> +	if (ret) {
> +		dev_err(dev, "failed to enable resources: %d\n", ret);
> +		goto err_clk;
> +	}
> +
> +	ret = dw_pcie_ep_init_registers(ep);
> +	if (ret) {
> +		dev_err(dev, "Failed to initialize DWC endpoint registers\n");
> +		goto err_init_regs;
> +	}
> +
> +	pci_epc_init_notify(ep->epc);
> +
> +	return 0;
> +
> +err_init_regs:
> +	stm32_pcie_disable_resources(stm32_pcie);
> +
> +err_clk:
> +	dw_pcie_ep_deinit(ep);
> +
> +err_init:
> +	pm_runtime_put_sync(dev);
> +	return ret;
> +}
> +
> +static int stm32_pcie_probe(struct platform_device *pdev)
> +{
> +	struct stm32_pcie *stm32_pcie;
> +	struct dw_pcie *dw;
> +	struct device *dev = &pdev->dev;
> +	int ret;
> +
> +	stm32_pcie = devm_kzalloc(dev, sizeof(*stm32_pcie), GFP_KERNEL);
> +	if (!stm32_pcie)
> +		return -ENOMEM;
> +
> +	dw = devm_kzalloc(dev, sizeof(*dw), GFP_KERNEL);
> +	if (!dw)
> +		return -ENOMEM;

Why can't you allocate it statically inside 'struct stm32_pcie'?

> +
> +	stm32_pcie->pci = dw;
> +
> +	dw->dev = dev;
> +	dw->ops = &dw_pcie_ops;
> +
> +	stm32_pcie->regmap = syscon_regmap_lookup_by_compatible("st,stm32mp25-syscfg");
> +	if (IS_ERR(stm32_pcie->regmap))
> +		return dev_err_probe(dev, PTR_ERR(stm32_pcie->regmap),
> +				     "No syscfg specified\n");
> +
> +	stm32_pcie->phy = devm_phy_get(dev, "pcie-phy");
> +	if (IS_ERR(stm32_pcie->phy))
> +		return dev_err_probe(dev, PTR_ERR(stm32_pcie->phy),
> +				     "failed to get pcie-phy\n");
> +
> +	stm32_pcie->clk = devm_clk_get(dev, NULL);
> +	if (IS_ERR(stm32_pcie->clk))
> +		return dev_err_probe(dev, PTR_ERR(stm32_pcie->clk),
> +				     "Failed to get PCIe clock source\n");
> +
> +	stm32_pcie->rst = devm_reset_control_get_exclusive(dev, NULL);
> +	if (IS_ERR(stm32_pcie->rst))
> +		return dev_err_probe(dev, PTR_ERR(stm32_pcie->rst),
> +				     "Failed to get PCIe reset\n");
> +
> +	stm32_pcie->perst_gpio = devm_gpiod_get(dev, "reset", GPIOD_IN);
> +	if (IS_ERR(stm32_pcie->perst_gpio))
> +		return dev_err_probe(dev, PTR_ERR(stm32_pcie->perst_gpio),
> +				     "Failed to get reset GPIO\n");
> +
> +	ret = phy_set_mode(stm32_pcie->phy, PHY_MODE_PCIE);

Hmm, so PHY mode is common for both endpoint and host?

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 1/5] dt-bindings: PCI: Add STM32MP25 PCIe root complex bindings

[Christian Bruel]

On 12/3/24 14:34, Manivannan Sadhasivam wrote:
> On Tue, Nov 26, 2024 at 04:51:15PM +0100, Christian Bruel wrote:
>> Document the bindings for STM32MP25 PCIe Controller configured in
>> root complex mode.
>>
>> Supports 4 legacy interrupts and MSI interrupts from the ARM
>> GICv2m controller.
>>
>> STM32 PCIe may be in a power domain which is the case for the STM32MP25
>> based boards.
>>
>> Supports wake# from wake-gpios
>>
>> Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
>> ---
>>   .../bindings/pci/st,stm32-pcie-common.yaml    | 45 +++++++++
>>   .../bindings/pci/st,stm32-pcie-host.yaml      | 99 +++++++++++++++++++
>>   2 files changed, 144 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml
>>   create mode 100644 Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml b/Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml
>> new file mode 100644
>> index 000000000000..479c03134da3
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/pci/st,stm32-pcie-common.yaml
>> @@ -0,0 +1,45 @@
>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/pci/st,stm32-pcie-common.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: STM32MP25 PCIe RC/EP controller
>> +
>> +maintainers:
>> +  - Christian Bruel <christian.bruel@foss.st.com>
>> +
>> +description:
>> +  STM32MP25 PCIe RC/EP common properties
>> +
>> +properties:
>> +  clocks:
>> +    maxItems: 1
>> +    description: PCIe system clock
>> +
>> +  resets:
>> +    maxItems: 1
>> +
>> +  phys:
>> +    maxItems: 1
>> +
>> +  phy-names:
>> +    const: pcie-phy
>> +
>> +  power-domains:
>> +    maxItems: 1
>> +
>> +  access-controllers:
>> +    maxItems: 1
>> +
>> +  reset-gpios:
>> +    description: GPIO controlled connection to PERST# signal
>> +    maxItems: 1
>> +
>> +required:
>> +  - clocks
>> +  - resets
>> +  - phys
>> +  - phy-names
>> +
>> +additionalProperties: true
>> diff --git a/Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml b/Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml
>> new file mode 100644
>> index 000000000000..18083cc69024
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/pci/st,stm32-pcie-host.yaml
>> @@ -0,0 +1,99 @@
>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/pci/st,stm32-pcie-host.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: STM32MP25 PCIe root complex driver
>> +
>> +maintainers:
>> +  - Christian Bruel <christian.bruel@foss.st.com>
>> +
>> +description:
>> +  PCIe root complex controller based on the Synopsys DesignWare PCIe core.
>> +
>> +allOf:
>> +  - $ref: /schemas/pci/snps,dw-pcie.yaml#
>> +  - $ref: /schemas/pci/st,stm32-pcie-common.yaml#
>> +
>> +select:
>> +  properties:
>> +    compatible:
>> +      const: st,stm32mp25-pcie-rc
>> +  required:
>> +    - compatible
>> +
>> +properties:
>> +  compatible:
>> +    const: st,stm32mp25-pcie-rc
>> +
>> +  reg:
>> +    items:
>> +      - description: Data Bus Interface (DBI) registers.
>> +      - description: PCIe configuration registers.
>> +
>> +  reg-names:
>> +    items:
>> +      - const: dbi
>> +      - const: config
>> +
>> +  num-lanes:
>> +    const: 1
>> +
>> +  msi-parent:
>> +    maxItems: 1
>> +
>> +  wake-gpios:
>> +    description: GPIO controlled connection to WAKE# input signal
>> +    maxItems: 1
>> +
>> +  wakeup-source: true
>> +
>> +dependentRequired:
>> +  wakeup-source: [ wake-gpios ]
>> +
>> +required:
>> +  - interrupt-map
>> +  - interrupt-map-mask
>> +  - ranges
>> +
>> +unevaluatedProperties: false
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/clock/st,stm32mp25-rcc.h>
>> +    #include <dt-bindings/gpio/gpio.h>
>> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
>> +    #include <dt-bindings/phy/phy.h>
>> +    #include <dt-bindings/reset/st,stm32mp25-rcc.h>
>> +
>> +    pcie@48400000 {
>> +        compatible = "st,stm32mp25-pcie-rc";
>> +        device_type = "pci";
>> +        num-lanes = <1>;
>> +        reg = <0x48400000 0x400000>,
>> +              <0x10000000 0x10000>;
>> +        reg-names = "dbi", "config";
>> +        #interrupt-cells = <1>;
>> +        interrupt-map-mask = <0 0 0 7>;
>> +        interrupt-map = <0 0 0 1 &intc 0 0 GIC_SPI 264 IRQ_TYPE_LEVEL_HIGH>,
>> +                        <0 0 0 2 &intc 0 0 GIC_SPI 265 IRQ_TYPE_LEVEL_HIGH>,
>> +                        <0 0 0 3 &intc 0 0 GIC_SPI 266 IRQ_TYPE_LEVEL_HIGH>,
>> +                        <0 0 0 4 &intc 0 0 GIC_SPI 267 IRQ_TYPE_LEVEL_HIGH>;
>> +        #address-cells = <3>;
>> +        #size-cells = <2>;
>> +        ranges = <0x01000000 0 0x10010000 0x10010000 0 0x10000>,
> 
> PCI address of I/O region should start from address 0x00000000.
> 
ok, thanks !

> Also use hex notation for all values.
> 
> - Mani
> 

Re: [PATCH v2 1/5] dt-bindings: PCI: Add STM32MP25 PCIe root complex bindings

[Bjorn Helgaas]

On Tue, Nov 26, 2024 at 04:51:15PM +0100, Christian Bruel wrote:
> Document the bindings for STM32MP25 PCIe Controller configured in
> root complex mode.
> 
> Supports 4 legacy interrupts and MSI interrupts from the ARM
> GICv2m controller.

s/legacy/INTx/

> STM32 PCIe may be in a power domain which is the case for the STM32MP25
> based boards.
> 
> Supports wake# from wake-gpios

s/wake#/WAKE#/

> +  wake-gpios:
> +    description: GPIO controlled connection to WAKE# input signal

I'm not a hardware guy, but this sounds like a GPIO that *reads*
WAKE#, not controls it.

> +    pcie@48400000 {
> +        compatible = "st,stm32mp25-pcie-rc";
> +        device_type = "pci";
> +        num-lanes = <1>;

num-lanes applies to a Root Port, not to a Root Complex.  I know most
bindings conflate Root Ports with the Root Complex, maybe because many
of these controllers only support a single Root Port?

But are we ever going to separate these out?  I assume someday
controllers will support multiple Root Ports and/or additional devices
on the root bus, like RCiEPs, RCECs, etc., and we'll need per-RP phys,
max-link-speed, num-lanes, reset-gpios, etc.

Seems like it would be to our benefit to split out the Root Ports when
we can, even if the current hardware only supports one, so we can
start untangling the code and data structures.

Bjorn

Re: [PATCH v2 2/5] PCI: stm32: Add PCIe host support for STM32MP25

[Christian Bruel]

Hello Bjorn and Lucas,

On 11/29/24 22:18, Lucas Stach wrote:
> Am Freitag, dem 29.11.2024 um 14:58 -0600 schrieb Bjorn Helgaas:
>> [+to Rob, DMA mask question]
>>
>> On Tue, Nov 26, 2024 at 04:51:16PM +0100, Christian Bruel wrote:
>>> Add driver for the STM32MP25 SoC PCIe Gen2 controller based on the
>>> DesignWare PCIe core.
>>
>> Can you include the numeric rate, not just "gen2", so we don't have to
>> search for it?
>>
>>> +static int stm32_pcie_resume_noirq(struct device *dev)
>>> +{
>>> +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
>>> +	struct dw_pcie *pci = stm32_pcie->pci;
>>> +	struct dw_pcie_rp *pp = &pci->pp;
>>> +	int ret;
>>> +
>>> +	/* init_state must be called first to force clk_req# gpio when no
>>> +	 * device is plugged.
>>> +	 */
>>
>> Use drivers/pci/ conventional comment style:
>>
>>    /*
>>     * text ...
>>     */
>>
>>> +static bool is_stm32_pcie_driver(struct device *dev)
>>> +{
>>> +	/* PCI bridge */
>>> +	dev = get_device(dev);
>>> +
>>> +	/* Platform driver */
>>> +	dev = get_device(dev->parent);
>>> +
>>> +	return (dev->driver == &stm32_pcie_driver.driver);
>>> +}
>>> +
>>> +/*
>>> + * DMA masters can only access the first 4GB of memory space,
>>> + * so we setup the bus DMA limit accordingly.
>>> + */
>>> +static int stm32_dma_limit(struct pci_dev *pdev, void *data)
>>> +{
>>> +	dev_dbg(&pdev->dev, "disabling DMA DAC for device");
>>> +
>>> +	pdev->dev.bus_dma_limit = DMA_BIT_MASK(32);
>>
>> I don't think this is the right way to do this.  Surely there's a way
>> to describe the DMA capability of the bridge once instead of iterating
>> over all the downstream devices?  This quirk can't work for hot-added
>> devices anyway.
>>

agree,

> This should simply be a dma-ranges property in the PCIe host controller
> DT node, which should describe the DMA address range limits for
> transactions passing through the host.

far better indeed, dma-ranges works like a charm

thanks,

> 
> Regards,
> Lucas
> 
>>> +	return 0;
>>> +}
>>> +
>>> +static void quirk_stm32_dma_mask(struct pci_dev *pci)
>>> +{
>>> +	struct pci_dev *root_port;
>>> +
>>> +	root_port = pcie_find_root_port(pci);
>>> +
>>> +	if (root_port && is_stm32_pcie_driver(root_port->dev.parent))
>>> +		pci_walk_bus(pci->bus, stm32_dma_limit, NULL);
>>> +}
>>> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SYNOPSYS, 0x0550, quirk_stm32_dma_mask);
>>
> 

Re: [PATCH v2 1/5] dt-bindings: PCI: Add STM32MP25 PCIe root complex bindings

[Christian Bruel]

On 12/3/24 23:25, Bjorn Helgaas wrote:
> On Tue, Nov 26, 2024 at 04:51:15PM +0100, Christian Bruel wrote:
>> Document the bindings for STM32MP25 PCIe Controller configured in
>> root complex mode.
>>
>> Supports 4 legacy interrupts and MSI interrupts from the ARM
>> GICv2m controller.
> 
> s/legacy/INTx/
> 
>> STM32 PCIe may be in a power domain which is the case for the STM32MP25
>> based boards.
>>
>> Supports wake# from wake-gpios
> 
> s/wake#/WAKE#/
> 
>> +  wake-gpios:
>> +    description: GPIO controlled connection to WAKE# input signal
> 
> I'm not a hardware guy, but this sounds like a GPIO that *reads*
> WAKE#, not controls it.

Rephrasing as
"GPIO used as WAKE# input signal" (output for the endpoint bindings)

> 
>> +    pcie@48400000 {
>> +        compatible = "st,stm32mp25-pcie-rc";
>> +        device_type = "pci";
>> +        num-lanes = <1>;
> 
> num-lanes applies to a Root Port, not to a Root Complex.  I know most
> bindings conflate Root Ports with the Root Complex, maybe because many
> of these controllers only support a single Root Port?
> 
> But are we ever going to separate these out?  I assume someday
> controllers will support multiple Root Ports and/or additional devices
> on the root bus, like RCiEPs, RCECs, etc., and we'll need per-RP phys,
> max-link-speed, num-lanes, reset-gpios, etc.
> 
> Seems like it would be to our benefit to split out the Root Ports when
> we can, even if the current hardware only supports one, so we can
> start untangling the code and data structures.

OK. and we support only 1 lane anyway, so drop it.

thanks,

> 
> Bjorn

Re: [PATCH v2 1/5] dt-bindings: PCI: Add STM32MP25 PCIe root complex bindings

[Bjorn Helgaas]

[cc->to: Rob for RC/RP separation conversation]

On Thu, Dec 05, 2024 at 02:41:26PM +0100, Christian Bruel wrote:
> On 12/3/24 23:25, Bjorn Helgaas wrote:
> > On Tue, Nov 26, 2024 at 04:51:15PM +0100, Christian Bruel wrote:
> > > Document the bindings for STM32MP25 PCIe Controller configured in
> > > root complex mode.
> > > 
> > > Supports 4 legacy interrupts and MSI interrupts from the ARM
> > > GICv2m controller.

> > > +  wake-gpios:
> > > +    description: GPIO controlled connection to WAKE# input signal
> > 
> > I'm not a hardware guy, but this sounds like a GPIO that *reads*
> > WAKE#, not controls it.
> 
> Rephrasing as
> "GPIO used as WAKE# input signal" (output for the endpoint bindings)

Perfect, that makes a lot of sense.

> > > +    pcie@48400000 {
> > > +        compatible = "st,stm32mp25-pcie-rc";
> > > +        device_type = "pci";
> > > +        num-lanes = <1>;
> > 
> > num-lanes applies to a Root Port, not to a Root Complex.  I know most
> > bindings conflate Root Ports with the Root Complex, maybe because many
> > of these controllers only support a single Root Port?
> > 
> > But are we ever going to separate these out?  I assume someday
> > controllers will support multiple Root Ports and/or additional devices
> > on the root bus, like RCiEPs, RCECs, etc., and we'll need per-RP phys,
> > max-link-speed, num-lanes, reset-gpios, etc.
> > 
> > Seems like it would be to our benefit to split out the Root Ports when
> > we can, even if the current hardware only supports one, so we can
> > start untangling the code and data structures.
> 
> OK. and we support only 1 lane anyway, so drop it.

Makes sense.  What about phys, resets, etc?  I'm pretty sure a PHY
would be a per-Root Port thing, and some resets and wakeup signals
also.

For new drivers, I think we should start adding Root Port stanzas to
specifically associate those things with the Root Port, e.g.,
something like this?

  pcie@48400000 {
    compatible = "st,stm32mp25-pcie-rc";

    pcie@0,0 {
      reg = <0x0000 0 0 0 0>;
      phys = <&combophy PHY_TYPE_PCIE>;
      phy-names = "pcie-phy";
    };
  };

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/pci/mediatek,mt7621-pcie.yaml?id=v6.12#n111
is one binding that does this, others include apple,pcie.yaml,
brcm,stb-pcie.yaml, hisilicon,kirin-pcie.yaml.

Bjorn

Re: [PATCH v2 1/5] dt-bindings: PCI: Add STM32MP25 PCIe root complex bindings

[Bjorn Helgaas]

On Tue, Nov 26, 2024 at 04:51:15PM +0100, Christian Bruel wrote:
> Document the bindings for STM32MP25 PCIe Controller configured in
> root complex mode.
> ...

> +        power-domains = <&CLUSTER_PD>;
> +    };
> +

Nit:

  Applying: dt-bindings: PCI: Add STM32MP25 PCIe root complex bindings
  .git/rebase-apply/patch:163: new blank line at EOF.
  +
  warning: 1 line adds whitespace errors.

Re: [PATCH v2 4/5] PCI: stm32: Add PCIe endpoint support for STM32MP25

[Bjorn Helgaas]

On Tue, Nov 26, 2024 at 04:51:18PM +0100, Christian Bruel wrote:
> Add driver to configure the STM32MP25 SoC PCIe Gen2 controller based on the
> DesignWare PCIe core in endpoint mode.

> +config PCIE_STM32_EP
> +	tristate "STMicroelectronics STM32MP25 PCIe Controller (endpoint mode)"
> +	depends on ARCH_STM32 || COMPILE_TEST
> +	depends on PCI_ENDPOINT
> +	select PCIE_DW_EP
> +	help
> +	  Enables endpoint support for DesignWare core based PCIe controller in found
> +	  in STM32MP25 SoC.

s/in found in/in/ (or "found in" if you prefer)

Wrap so help text fits in 80 columns when for "make menuconfig".

> +static void stm32_pcie_ep_init(struct dw_pcie_ep *ep)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
> +	enum pci_barno bar;
> +
> +	for (bar = 0; bar < PCI_STD_NUM_BARS; bar++)
> +		dw_pcie_ep_reset_bar(pci, bar);
> +
> +	/* Defer Completion Requests until link started */

I asked about this before [1] but didn't finish the conversation.  My
main point is that I think "Completion Request" is a misnomer.
There's a "Configuration Request" and a "Completion," but no such
thing as a "Completion Request."

Based on your previous response, I think this should say something
like "respond to config requests with Request Retry Status (RRS) until
we're prepared to handle them."

> +	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
> +			   STM32MP25_PCIECR_REQ_RETRY_EN,
> +			   STM32MP25_PCIECR_REQ_RETRY_EN);
> +}
> +
> +static int stm32_pcie_enable_link(struct dw_pcie *pci)
> +{
> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
> +	int ret;
> +
> +	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
> +			   STM32MP25_PCIECR_LTSSM_EN,
> +			   STM32MP25_PCIECR_LTSSM_EN);
> +
> +	ret = dw_pcie_wait_for_link(pci);
> +	if (ret)
> +		return ret;
> +
> +	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
> +			   STM32MP25_PCIECR_REQ_RETRY_EN,
> +			   0);

And I assume this means the endpoint will accept config requests and
handle them normally instead of responding with RRS.

Strictly speaking this is a different condition than "the link is up"
because the link must be up in order to even receive a config request.
The purpose of RRS is for devices that need more initialization time
after the link is up before they can respond to config requests.

The fact that the hardware provides this bit makes me think the
designer anticipated that the link might come up before the rest of
the device is fully initialized.

Bjorn

[1] https://lore.kernel.org/r/20241112203846.GA1856246@bhelgaas

Re: [PATCH v2 2/5] PCI: stm32: Add PCIe host support for STM32MP25

[kernel test robot]

Hi Christian,

kernel test robot noticed the following build errors:

[auto build test ERROR on pci/next]
[also build test ERROR on pci/for-linus linus/master v6.13-rc1 next-20241206]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Christian-Bruel/dt-bindings-PCI-Add-STM32MP25-PCIe-root-complex-bindings/20241128-101958
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
patch link:    https://lore.kernel.org/r/20241126155119.1574564-3-christian.bruel%40foss.st.com
patch subject: [PATCH v2 2/5] PCI: stm32: Add PCIe host support for STM32MP25
config: openrisc-randconfig-r072-20241208 (https://download.01.org/0day-ci/archive/20241208/202412080849.1SXhxzpi-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241208/202412080849.1SXhxzpi-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202412080849.1SXhxzpi-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/pci/controller/dwc/pcie-stm32.c: In function 'stm32_pcie_suspend_noirq':
>> drivers/pci/controller/dwc/pcie-stm32.c:101:16: error: implicit declaration of function 'pinctrl_pm_select_sleep_state' [-Wimplicit-function-declaration]
     101 |         return pinctrl_pm_select_sleep_state(dev);
         |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/pci/controller/dwc/pcie-stm32.c: In function 'stm32_pcie_resume_noirq':
>> drivers/pci/controller/dwc/pcie-stm32.c:114:24: error: 'struct device' has no member named 'pins'
     114 |         if (!IS_ERR(dev->pins->init_state))
         |                        ^~
>> drivers/pci/controller/dwc/pcie-stm32.c:115:23: error: implicit declaration of function 'pinctrl_select_state' [-Wimplicit-function-declaration]
     115 |                 ret = pinctrl_select_state(dev->pins->p, dev->pins->init_state);
         |                       ^~~~~~~~~~~~~~~~~~~~
   drivers/pci/controller/dwc/pcie-stm32.c:115:47: error: 'struct device' has no member named 'pins'
     115 |                 ret = pinctrl_select_state(dev->pins->p, dev->pins->init_state);
         |                                               ^~
   drivers/pci/controller/dwc/pcie-stm32.c:115:61: error: 'struct device' has no member named 'pins'
     115 |                 ret = pinctrl_select_state(dev->pins->p, dev->pins->init_state);
         |                                                             ^~
>> drivers/pci/controller/dwc/pcie-stm32.c:117:23: error: implicit declaration of function 'pinctrl_pm_select_default_state' [-Wimplicit-function-declaration]
     117 |                 ret = pinctrl_pm_select_default_state(dev);
         |                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/pci/controller/dwc/pcie-stm32.c: In function 'stm32_pcie_probe':
   drivers/pci/controller/dwc/pcie-stm32.c:243:29: warning: unused variable 'np' [-Wunused-variable]
     243 |         struct device_node *np = pdev->dev.of_node;
         |                             ^~


vim +/pinctrl_pm_select_sleep_state +101 drivers/pci/controller/dwc/pcie-stm32.c

    88	
    89	static int stm32_pcie_suspend_noirq(struct device *dev)
    90	{
    91		struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
    92	
    93		stm32_pcie->link_is_up = dw_pcie_link_up(stm32_pcie->pci);
    94	
    95		stm32_pcie_stop_link(stm32_pcie->pci);
    96		clk_disable_unprepare(stm32_pcie->clk);
    97	
    98		if (!device_may_wakeup(dev) && !device_wakeup_path(dev))
    99			phy_exit(stm32_pcie->phy);
   100	
 > 101		return pinctrl_pm_select_sleep_state(dev);
   102	}
   103	
   104	static int stm32_pcie_resume_noirq(struct device *dev)
   105	{
   106		struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
   107		struct dw_pcie *pci = stm32_pcie->pci;
   108		struct dw_pcie_rp *pp = &pci->pp;
   109		int ret;
   110	
   111		/* init_state must be called first to force clk_req# gpio when no
   112		 * device is plugged.
   113		 */
 > 114		if (!IS_ERR(dev->pins->init_state))
 > 115			ret = pinctrl_select_state(dev->pins->p, dev->pins->init_state);
   116		else
 > 117			ret = pinctrl_pm_select_default_state(dev);
   118	
   119		if (ret) {
   120			dev_err(dev, "Failed to activate pinctrl pm state: %d\n", ret);
   121			return ret;
   122		}
   123	
   124		if (!device_may_wakeup(dev) && !device_wakeup_path(dev)) {
   125			ret = phy_init(stm32_pcie->phy);
   126			if (ret) {
   127				pinctrl_pm_select_default_state(dev);
   128				return ret;
   129			}
   130		}
   131	
   132		ret = clk_prepare_enable(stm32_pcie->clk);
   133		if (ret)
   134			goto clk_err;
   135	
   136		ret = dw_pcie_setup_rc(pp);
   137		if (ret)
   138			goto pcie_err;
   139	
   140		if (stm32_pcie->link_is_up) {
   141			ret = stm32_pcie_start_link(stm32_pcie->pci);
   142			if (ret)
   143				goto pcie_err;
   144	
   145			/* Ignore errors, the link may come up later */
   146			dw_pcie_wait_for_link(stm32_pcie->pci);
   147		}
   148	
   149		pinctrl_pm_select_default_state(dev);
   150	
   151		return 0;
   152	
   153	pcie_err:
   154		dw_pcie_host_deinit(pp);
   155		clk_disable_unprepare(stm32_pcie->clk);
   156	clk_err:
   157		phy_exit(stm32_pcie->phy);
   158		pinctrl_pm_select_default_state(dev);
   159	
   160		return ret;
   161	}
   162	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v2 2/5] PCI: stm32: Add PCIe host support for STM32MP25

[Christian Bruel]

Hi Manivannan,

On 12/3/24 15:52, Manivannan Sadhasivam wrote:
> On Tue, Nov 26, 2024 at 04:51:16PM +0100, Christian Bruel wrote:
>> Add driver for the STM32MP25 SoC PCIe Gen2 controller based on the
>> DesignWare PCIe core.
>>
>> Supports MSI via GICv2m, Single Virtual Channel, Single Function
>>
>> Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
>> ---
>>   drivers/pci/controller/dwc/Kconfig      |  12 +
>>   drivers/pci/controller/dwc/Makefile     |   1 +
>>   drivers/pci/controller/dwc/pcie-stm32.c | 402 ++++++++++++++++++++++++
>>   drivers/pci/controller/dwc/pcie-stm32.h |  15 +
>>   4 files changed, 430 insertions(+)
>>   create mode 100644 drivers/pci/controller/dwc/pcie-stm32.c
>>   create mode 100644 drivers/pci/controller/dwc/pcie-stm32.h
>>
>> diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
>> index b6d6778b0698..0c18879b604c 100644
>> --- a/drivers/pci/controller/dwc/Kconfig
>> +++ b/drivers/pci/controller/dwc/Kconfig
>> @@ -389,6 +389,18 @@ config PCIE_SPEAR13XX
>>   	help
>>   	  Say Y here if you want PCIe support on SPEAr13XX SoCs.
>>   
>> +config PCIE_STM32
>> +	tristate "STMicroelectronics STM32MP25 PCIe Controller (host mode)"
>> +	depends on ARCH_STM32 || COMPILE_TEST
>> +	depends on PCI_MSI
>> +	select PCIE_DW_HOST
>> +	help
>> +	  Enables support for the DesignWare core based PCIe host controller
>> +	  found in STM32MP25 SoC.
>> +
>> +	  This driver can also be built as a module. If so, the module
>> +	  will be called pcie-stm32.
>> +
>>   config PCI_DRA7XX
>>   	tristate
>>   
>> diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
>> index a8308d9ea986..576d99cb3bc5 100644
>> --- a/drivers/pci/controller/dwc/Makefile
>> +++ b/drivers/pci/controller/dwc/Makefile
>> @@ -28,6 +28,7 @@ obj-$(CONFIG_PCIE_UNIPHIER) += pcie-uniphier.o
>>   obj-$(CONFIG_PCIE_UNIPHIER_EP) += pcie-uniphier-ep.o
>>   obj-$(CONFIG_PCIE_VISCONTI_HOST) += pcie-visconti.o
>>   obj-$(CONFIG_PCIE_RCAR_GEN4) += pcie-rcar-gen4.o
>> +obj-$(CONFIG_PCIE_STM32) += pcie-stm32.o
>>   
>>   # The following drivers are for devices that use the generic ACPI
>>   # pci_root.c driver but don't support standard ECAM config access.
>> diff --git a/drivers/pci/controller/dwc/pcie-stm32.c b/drivers/pci/controller/dwc/pcie-stm32.c
>> new file mode 100644
>> index 000000000000..fa787406c0e4
>> --- /dev/null
>> +++ b/drivers/pci/controller/dwc/pcie-stm32.c
>> @@ -0,0 +1,402 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * STMicroelectronics STM32MP25 PCIe root complex driver.
>> + *
>> + * Copyright (C) 2024 STMicroelectronics
>> + * Author: Christian Bruel <christian.bruel@foss.st.com>
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/of_platform.h>
>> +#include <linux/phy/phy.h>
>> +#include <linux/pinctrl/devinfo.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/regmap.h>
>> +#include <linux/reset.h>
>> +#include "pcie-designware.h"
>> +#include "pcie-stm32.h"
>> +#include "../../pci.h"
>> +
>> +struct stm32_pcie {
>> +	struct dw_pcie *pci;
>> +	struct regmap *regmap;
>> +	struct reset_control *rst;
>> +	struct phy *phy;
>> +	struct clk *clk;
>> +	struct gpio_desc *perst_gpio;
>> +	struct gpio_desc *wake_gpio;
>> +	unsigned int wake_irq;
>> +	bool link_is_up;
>> +};
>> +
>> +static int stm32_pcie_start_link(struct dw_pcie *pci)
>> +{
>> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
>> +	u32 ret;
>> +
>> +	if (stm32_pcie->perst_gpio) {
> 
> gpiod_set_value() will bail out if 'perst_gpio' is NULL. So no need to add a
> check.

OK

> 
>> +		/* Make sure PERST# is asserted. */
> 
> Why?

Ack. We have GPIOD_OUT_HIGH already thanks devm_gpiod_get_optional, so 
PERST# is asserted already at probe


> 
>> +		gpiod_set_value(stm32_pcie->perst_gpio, 1);
>> +
>> +		fsleep(PCIE_T_PERST_CLK_US);
>> +		gpiod_set_value(stm32_pcie->perst_gpio, 0);
> 
> Why can't you deassert PERST# in stm32_add_pcie_port()?

Code reuse between probe and resume. (Need de-assert PERST# after the 
refclk is stable from both probe or resume_noirq paths).
Can move this from start_link to:
  - probe after the phy_init
  - and resume_no_irq after the phy_init
before dw_pcie_setup_rc

> 
>> +	}
>> +
>> +	ret = regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
>> +				 STM32MP25_PCIECR_LTSSM_EN,
>> +				 STM32MP25_PCIECR_LTSSM_EN);
>> +
>> +	if (stm32_pcie->perst_gpio)
> 
> It doesn't hurt to call msleep() always.

It is optional in the DT. Why wait if we don't have a reset signal ?

> 
>> +		msleep(PCIE_T_RRS_READY_MS);
>> +
>> +	return ret;
>> +}
>> +
>> +static void stm32_pcie_stop_link(struct dw_pcie *pci)
>> +{
>> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
>> +
>> +	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
>> +			   STM32MP25_PCIECR_LTSSM_EN, 0);
>> +
>> +	/* Assert PERST# */
>> +	if (stm32_pcie->perst_gpio)
>> +		gpiod_set_value(stm32_pcie->perst_gpio, 1);
> 
> I don't like tying PERST# handling with start/stop link. PERST# should be
> handled based on the power/clock state.

I don't understand your point: We turn off the PHY in suspend_noirq(), 
so that seems a logical place to de-assert in resume_noirq after the 
refclk is ready. PERST# should be kept active until the PHY stablilizes 
the clock in resume. From the PCIe electromechanical specs, PERST# goes 
active while the refclk is not stable/


> 
>> +}
>> +
>> +static int stm32_pcie_suspend(struct device *dev)
>> +{
>> +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
>> +
>> +	if (device_may_wakeup(dev) || device_wakeup_path(dev))
>> +		enable_irq_wake(stm32_pcie->wake_irq);
>> +
>> +	return 0;
>> +}
>> +
>> +static int stm32_pcie_resume(struct device *dev)
>> +{
>> +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
>> +
>> +	if (device_may_wakeup(dev) || device_wakeup_path(dev))
>> +		disable_irq_wake(stm32_pcie->wake_irq);
>> +
>> +	return 0;
>> +}
>> +
>> +static int stm32_pcie_suspend_noirq(struct device *dev)
>> +{
>> +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
>> +
>> +	stm32_pcie->link_is_up = dw_pcie_link_up(stm32_pcie->pci);
>> +
>> +	stm32_pcie_stop_link(stm32_pcie->pci);
> 
> I don't understand how endpoint can wakeup the host if PERST# gets asserted.

The stm32 PCIe doesn't support L2, we don't expect an in-band beacon for 
the wakeup. We support wakeup only from sideband WAKE#, that will 
restart the link from IRQ

> 
>> +	clk_disable_unprepare(stm32_pcie->clk);
>> +
>> +	if (!device_may_wakeup(dev) && !device_wakeup_path(dev))
>> +		phy_exit(stm32_pcie->phy);
>> +
>> +	return pinctrl_pm_select_sleep_state(dev);
>> +}
>> +
>> +static int stm32_pcie_resume_noirq(struct device *dev)
>> +{
>> +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
>> +	struct dw_pcie *pci = stm32_pcie->pci;
>> +	struct dw_pcie_rp *pp = &pci->pp;
>> +	int ret;
>> +
>> +	/* init_state must be called first to force clk_req# gpio when no
> 
> CLKREQ#
> 
> Why RC should control CLKREQ#?

REFCLK is gated with CLKREQ#, So we cannot access the core
without CLKREQ# if no device is present. So force it with a init pinmux
the time to init the PHY and the core DBI registers

> 
> Also please use preferred style for multi-line comments:
> 
> 	/*
> 	 * ...
> 	 */
> 
>> +	 * device is plugged.
>> +	 */
>> +	if (!IS_ERR(dev->pins->init_state))
>> +		ret = pinctrl_select_state(dev->pins->p, dev->pins->init_state);
>> +	else
>> +		ret = pinctrl_pm_select_default_state(dev);
>> +
>> +	if (ret) {
>> +		dev_err(dev, "Failed to activate pinctrl pm state: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	if (!device_may_wakeup(dev) && !device_wakeup_path(dev)) {
>> +		ret = phy_init(stm32_pcie->phy);
>> +		if (ret) {
>> +			pinctrl_pm_select_default_state(dev);
>> +			return ret;
>> +		}
>> +	}
>> +
>> +	ret = clk_prepare_enable(stm32_pcie->clk);
>> +	if (ret)
>> +		goto clk_err;
> 
> Please name the goto labels of their purpose. Like err_phy_exit.

OK

> 
>> +
>> +	ret = dw_pcie_setup_rc(pp);
>> +	if (ret)
>> +		goto pcie_err;
> 
> This should be, 'err_disable_clk'.
> 
>> +
>> +	if (stm32_pcie->link_is_up) {
> 
> Why do you need this check? You cannot start the link in the absence of an
> endpoint?
> 

It is an optimization to avoid unnecessary "dw_pcie_wait_for_link" if no 
device is present during suspend


>> +		ret = stm32_pcie_start_link(stm32_pcie->pci);
>> +		if (ret)
>> +			goto pcie_err;
>> +
>> +		/* Ignore errors, the link may come up later */
>> +		dw_pcie_wait_for_link(stm32_pcie->pci);
>> +	}
>> +
>> +	pinctrl_pm_select_default_state(dev);
>> +
>> +	return 0;
>> +
>> +pcie_err:
>> +	dw_pcie_host_deinit(pp);
>> +	clk_disable_unprepare(stm32_pcie->clk);
>> +clk_err:
>> +	phy_exit(stm32_pcie->phy);
>> +	pinctrl_pm_select_default_state(dev);
>> +
>> +	return ret;
>> +}
>> +
>> +static const struct dev_pm_ops stm32_pcie_pm_ops = {
>> +	NOIRQ_SYSTEM_SLEEP_PM_OPS(stm32_pcie_suspend_noirq,
>> +				  stm32_pcie_resume_noirq)
> 
> Can you make use of dw_pcie_{suspend/resume}_noirq() APIs?

dw_pcie_suspend_noirq bails out with read_poll_timeout on ltssm = 
DW_PCIE_LTSS_L2_IDLE. We don't support L2.

> 
>> +	SYSTEM_SLEEP_PM_OPS(stm32_pcie_suspend, stm32_pcie_resume)
>> +};
>> +
>> +static const struct dw_pcie_host_ops stm32_pcie_host_ops = {
>> +};
>> +
>> +static const struct dw_pcie_ops dw_pcie_ops = {
>> +	.start_link = stm32_pcie_start_link,
>> +	.stop_link = stm32_pcie_stop_link
>> +};
>> +
> 
> [...]
> 
>> +	if (device_property_read_bool(dev, "wakeup-source")) {
>> +		stm32_pcie->wake_gpio = devm_gpiod_get_optional(dev, "wake",
>> +								GPIOD_IN);
>> +		if (IS_ERR(stm32_pcie->wake_gpio))
>> +			return dev_err_probe(dev, PTR_ERR(stm32_pcie->wake_gpio),
>> +					     "Failed to get wake GPIO\n");
>> +	}
>> +
>> +	if (stm32_pcie->wake_gpio) {
>> +		stm32_pcie->wake_irq = gpiod_to_irq(stm32_pcie->wake_gpio);
>> +
>> +		ret = devm_request_threaded_irq(&pdev->dev,
>> +						stm32_pcie->wake_irq, NULL,
>> +						stm32_pcie_wake_irq_handler,
>> +						IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
>> +						"wake_irq", stm32_pcie);
>> +
>> +		if (ret)
>> +			return dev_err_probe(dev, ret, "Failed to request WAKE IRQ: %d\n", ret);
>> +	}
> 
> Can we move WAKE# gpio handling to DWC core? There is nothing STM32 specific
> here.
> 

OK

>> +
>> +	ret = devm_pm_runtime_enable(dev);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to enable runtime PM %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	ret = pm_runtime_resume_and_get(dev);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to get runtime PM %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	ret = stm32_add_pcie_port(stm32_pcie, pdev);
>> +	if (ret)  {
>> +		pm_runtime_put_sync(&pdev->dev);
>> +		return ret;
>> +	}
>> +
>> +	if (stm32_pcie->wake_gpio)
>> +		device_set_wakeup_capable(dev, true);
>> +
>> +	return 0;
>> +}
>> +
>> +static void stm32_pcie_remove(struct platform_device *pdev)
>> +{
>> +	struct stm32_pcie *stm32_pcie = platform_get_drvdata(pdev);
>> +	struct dw_pcie_rp *pp = &stm32_pcie->pci->pp;
>> +
>> +	if (stm32_pcie->wake_gpio)
>> +		device_init_wakeup(&pdev->dev, false);
>> +
>> +	dw_pcie_host_deinit(pp);
>> +	clk_disable_unprepare(stm32_pcie->clk);
>> +
>> +	phy_exit(stm32_pcie->phy);
>> +
>> +	pm_runtime_put_sync(&pdev->dev);
>> +}
>> +
>> +static const struct of_device_id stm32_pcie_of_match[] = {
>> +	{ .compatible = "st,stm32mp25-pcie-rc" },
>> +	{},
>> +};
>> +
>> +static struct platform_driver stm32_pcie_driver = {
>> +	.probe = stm32_pcie_probe,
>> +	.remove = stm32_pcie_remove,
>> +	.driver = {
>> +		.name = "stm32-pcie",
>> +		.of_match_table = stm32_pcie_of_match,
>> +		.pm		= &stm32_pcie_pm_ops,
> 
> Just use a single space instead of tab.
> 
> Could you also set PROBE_PREFER_ASYNCHRONOUS to allow async probing of
> controller drivers?

OK

> 
>> +	},
>> +};
>> +
>> +static bool is_stm32_pcie_driver(struct device *dev)
>> +{
>> +	/* PCI bridge */
>> +	dev = get_device(dev);
>> +
>> +	/* Platform driver */
>> +	dev = get_device(dev->parent);
>> +
>> +	return (dev->driver == &stm32_pcie_driver.driver);
>> +}
>> +
>> +/*
>> + * DMA masters can only access the first 4GB of memory space,
>> + * so we setup the bus DMA limit accordingly.
>> + */
>> +static int stm32_dma_limit(struct pci_dev *pdev, void *data)
>> +{
>> +	dev_dbg(&pdev->dev, "disabling DMA DAC for device");
>> +
>> +	pdev->dev.bus_dma_limit = DMA_BIT_MASK(32);
>> +
>> +	return 0;
>> +}
>> +
>> +static void quirk_stm32_dma_mask(struct pci_dev *pci)
>> +{
>> +	struct pci_dev *root_port;
>> +
>> +	root_port = pcie_find_root_port(pci);
>> +
>> +	if (root_port && is_stm32_pcie_driver(root_port->dev.parent))
>> +		pci_walk_bus(pci->bus, stm32_dma_limit, NULL);
>> +}
>> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SYNOPSYS, 0x0550, quirk_stm32_dma_mask);
> 
> This is not the correct way of using DMA masks as Bjorn noted.

Yes, fixed will dma-ranges

thanks

Christian

> 
> - Mani
> 

Re: [PATCH v2 4/5] PCI: stm32: Add PCIe endpoint support for STM32MP25

[Christian Bruel]

Hi Manivanna,

On 12/3/24 16:22, Manivannan Sadhasivam wrote:
> On Tue, Nov 26, 2024 at 04:51:18PM +0100, Christian Bruel wrote:
> 
> [...]
> 
>> +static int stm32_pcie_start_link(struct dw_pcie *pci)
>> +{
>> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
>> +	int ret;
>> +
>> +	if (stm32_pcie->link_status == STM32_PCIE_EP_LINK_ENABLED) {
>> +		dev_dbg(pci->dev, "Link is already enabled\n");
>> +		return 0;
>> +	}
>> +
>> +	ret = stm32_pcie_enable_link(pci);
>> +	if (ret) {
>> +		dev_err(pci->dev, "PCIe cannot establish link: %d\n", ret);
>> +		return ret;
>> +	}
> 
> How the REFCLK is supplied to the endpoint? From host or generated locally?

 From Host only, we don't support the separated clock model.

> 
>> +
>> +	stm32_pcie->link_status = STM32_PCIE_EP_LINK_ENABLED;
>> +
>> +	enable_irq(stm32_pcie->perst_irq);
>> +
>> +	return 0;
>> +}
>> +
>> +static void stm32_pcie_stop_link(struct dw_pcie *pci)
>> +{
>> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
>> +
>> +	if (stm32_pcie->link_status == STM32_PCIE_EP_LINK_DISABLED) {
>> +		dev_dbg(pci->dev, "Link is already disabled\n");
>> +		return;
>> +	}
>> +
>> +	disable_irq(stm32_pcie->perst_irq);
>> +
>> +	stm32_pcie_disable_link(pci);
>> +
>> +	stm32_pcie->link_status = STM32_PCIE_EP_LINK_DISABLED;
>> +}
>> +
>> +static int stm32_pcie_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
>> +				unsigned int type, u16 interrupt_num)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>> +
>> +	switch (type) {
>> +	case PCI_IRQ_INTX:
>> +		return dw_pcie_ep_raise_intx_irq(ep, func_no);
>> +	case PCI_IRQ_MSI:
>> +		return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
>> +	default:
>> +		dev_err(pci->dev, "UNKNOWN IRQ type\n");
>> +		return -EINVAL;
>> +	}
>> +}
>> +
>> +static const struct pci_epc_features stm32_pcie_epc_features = {
>> +	.msi_capable = true,
>> +	.align = 1 << 16,
> 
> Use SZ_64K
> 

OK

>> +};
>> +
> 
> [...]
> 
>> +static int stm32_add_pcie_ep(struct stm32_pcie *stm32_pcie,
>> +			     struct platform_device *pdev)
>> +{
>> +	struct dw_pcie *pci = stm32_pcie->pci;
>> +	struct dw_pcie_ep *ep = &pci->ep;
>> +	struct device *dev = &pdev->dev;
>> +	int ret;
>> +
>> +	ret = regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
>> +				 STM32MP25_PCIECR_TYPE_MASK,
>> +				 STM32MP25_PCIECR_EP);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = pm_runtime_resume_and_get(dev);
>> +	if (ret < 0) {
>> +		dev_err(dev, "pm runtime resume failed: %d\n", ret);
>> +		return ret;
>> +	}
> 
> You might want to do runtime resume before accessing regmap.

OK

>> +
>> +	reset_control_assert(stm32_pcie->rst);
>> +	reset_control_deassert(stm32_pcie->rst);
>> +
>> +	ep->ops = &stm32_pcie_ep_ops;
>> +
>> +	ret = dw_pcie_ep_init(ep);
>> +	if (ret) {
>> +		dev_err(dev, "failed to initialize ep: %d\n", ret);
>> +		goto err_init;
>> +	}
>> +
>> +	ret = stm32_pcie_enable_resources(stm32_pcie);
>> +	if (ret) {
>> +		dev_err(dev, "failed to enable resources: %d\n", ret);
>> +		goto err_clk;
>> +	}
>> +
>> +	ret = dw_pcie_ep_init_registers(ep);
>> +	if (ret) {
>> +		dev_err(dev, "Failed to initialize DWC endpoint registers\n");
>> +		goto err_init_regs;
>> +	}
>> +
>> +	pci_epc_init_notify(ep->epc);
>> +
>> +	return 0;
>> +
>> +err_init_regs:
>> +	stm32_pcie_disable_resources(stm32_pcie);
>> +
>> +err_clk:
>> +	dw_pcie_ep_deinit(ep);
>> +
>> +err_init:
>> +	pm_runtime_put_sync(dev);
>> +	return ret;
>> +}
>> +
>> +static int stm32_pcie_probe(struct platform_device *pdev)
>> +{
>> +	struct stm32_pcie *stm32_pcie;
>> +	struct dw_pcie *dw;
>> +	struct device *dev = &pdev->dev;
>> +	int ret;
>> +
>> +	stm32_pcie = devm_kzalloc(dev, sizeof(*stm32_pcie), GFP_KERNEL);
>> +	if (!stm32_pcie)
>> +		return -ENOMEM;
>> +
>> +	dw = devm_kzalloc(dev, sizeof(*dw), GFP_KERNEL);
>> +	if (!dw)
>> +		return -ENOMEM;
> 
> Why can't you allocate it statically inside 'struct stm32_pcie'?

Will do

> 
>> +
>> +	stm32_pcie->pci = dw;
>> +
>> +	dw->dev = dev;
>> +	dw->ops = &dw_pcie_ops;
>> +
>> +	stm32_pcie->regmap = syscon_regmap_lookup_by_compatible("st,stm32mp25-syscfg");
>> +	if (IS_ERR(stm32_pcie->regmap))
>> +		return dev_err_probe(dev, PTR_ERR(stm32_pcie->regmap),
>> +				     "No syscfg specified\n");
>> +
>> +	stm32_pcie->phy = devm_phy_get(dev, "pcie-phy");
>> +	if (IS_ERR(stm32_pcie->phy))
>> +		return dev_err_probe(dev, PTR_ERR(stm32_pcie->phy),
>> +				     "failed to get pcie-phy\n");
>> +
>> +	stm32_pcie->clk = devm_clk_get(dev, NULL);
>> +	if (IS_ERR(stm32_pcie->clk))
>> +		return dev_err_probe(dev, PTR_ERR(stm32_pcie->clk),
>> +				     "Failed to get PCIe clock source\n");
>> +
>> +	stm32_pcie->rst = devm_reset_control_get_exclusive(dev, NULL);
>> +	if (IS_ERR(stm32_pcie->rst))
>> +		return dev_err_probe(dev, PTR_ERR(stm32_pcie->rst),
>> +				     "Failed to get PCIe reset\n");
>> +
>> +	stm32_pcie->perst_gpio = devm_gpiod_get(dev, "reset", GPIOD_IN);
>> +	if (IS_ERR(stm32_pcie->perst_gpio))
>> +		return dev_err_probe(dev, PTR_ERR(stm32_pcie->perst_gpio),
>> +				     "Failed to get reset GPIO\n");
>> +
>> +	ret = phy_set_mode(stm32_pcie->phy, PHY_MODE_PCIE);
> 
> Hmm, so PHY mode is common for both endpoint and host?

Yes it is. We need to init the phy here because it is a clock source for 
the PCIe core clk

Thanks

Christian

> 
> - Mani
> 

Re: [PATCH v2 4/5] PCI: stm32: Add PCIe endpoint support for STM32MP25

[Christian Bruel]

On 12/5/24 18:27, Bjorn Helgaas wrote:
> On Tue, Nov 26, 2024 at 04:51:18PM +0100, Christian Bruel wrote:
>> Add driver to configure the STM32MP25 SoC PCIe Gen2 controller based on the
>> DesignWare PCIe core in endpoint mode.
> 
>> +config PCIE_STM32_EP
>> +	tristate "STMicroelectronics STM32MP25 PCIe Controller (endpoint mode)"
>> +	depends on ARCH_STM32 || COMPILE_TEST
>> +	depends on PCI_ENDPOINT
>> +	select PCIE_DW_EP
>> +	help
>> +	  Enables endpoint support for DesignWare core based PCIe controller in found
>> +	  in STM32MP25 SoC.
> 
> s/in found in/in/ (or "found in" if you prefer)
> 
> Wrap so help text fits in 80 columns when for "make menuconfig".
> 
>> +static void stm32_pcie_ep_init(struct dw_pcie_ep *ep)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
>> +	enum pci_barno bar;
>> +
>> +	for (bar = 0; bar < PCI_STD_NUM_BARS; bar++)
>> +		dw_pcie_ep_reset_bar(pci, bar);
>> +
>> +	/* Defer Completion Requests until link started */
> 
> I asked about this before [1] but didn't finish the conversation.  My
> main point is that I think "Completion Request" is a misnomer.
> There's a "Configuration Request" and a "Completion," but no such
> thing as a "Completion Request."
> 
> Based on your previous response, I think this should say something
> like "respond to config requests with Request Retry Status (RRS) until
> we're prepared to handle them."

OK thanks for the phrasing. This is inline with the DWC doc:
"... controller completes incoming configuration requests with a
configuration request retry status."
The only thing is that the PCIe specs talks about CRS, not RRS.

so slightly change to
"respond to config requests with Configuration Request Retry Status 
(CRS) until we're prepared to handle them."


> 
>> +	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
>> +			   STM32MP25_PCIECR_REQ_RETRY_EN,
>> +			   STM32MP25_PCIECR_REQ_RETRY_EN);
>> +}
>> +
>> +static int stm32_pcie_enable_link(struct dw_pcie *pci)
>> +{
>> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
>> +	int ret;
>> +
>> +	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
>> +			   STM32MP25_PCIECR_LTSSM_EN,
>> +			   STM32MP25_PCIECR_LTSSM_EN);
>> +
>> +	ret = dw_pcie_wait_for_link(pci);
>> +	if (ret)
>> +		return ret;
>> +
>> +	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
>> +			   STM32MP25_PCIECR_REQ_RETRY_EN,
>> +			   0);
> 
> And I assume this means the endpoint will accept config requests and
> handle them normally instead of responding with RRS.
> 
> Strictly speaking this is a different condition than "the link is up"
> because the link must be up in order to even receive a config request.
> The purpose of RRS is for devices that need more initialization time
> after the link is up before they can respond to config requests.
> 
> The fact that the hardware provides this bit makes me think the
> designer anticipated that the link might come up before the rest of
> the device is fully initialized.

Agree, this there are 2 conditions in this function: link is up + 
accepting config requests. I'll split or rename

Thanks
Christian
> 
> Bjorn
> 
> [1] https://lore.kernel.org/r/20241112203846.GA1856246@bhelgaas
> 

Re: [PATCH v2 4/5] PCI: stm32: Add PCIe endpoint support for STM32MP25

[Manivannan Sadhasivam]

On Mon, Dec 16, 2024 at 11:02:07AM +0100, Christian Bruel wrote:
> Hi Manivanna,
> 
> On 12/3/24 16:22, Manivannan Sadhasivam wrote:
> > On Tue, Nov 26, 2024 at 04:51:18PM +0100, Christian Bruel wrote:
> > 
> > [...]
> > 
> > > +static int stm32_pcie_start_link(struct dw_pcie *pci)
> > > +{
> > > +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
> > > +	int ret;
> > > +
> > > +	if (stm32_pcie->link_status == STM32_PCIE_EP_LINK_ENABLED) {
> > > +		dev_dbg(pci->dev, "Link is already enabled\n");
> > > +		return 0;
> > > +	}
> > > +
> > > +	ret = stm32_pcie_enable_link(pci);
> > > +	if (ret) {
> > > +		dev_err(pci->dev, "PCIe cannot establish link: %d\n", ret);
> > > +		return ret;
> > > +	}
> > 
> > How the REFCLK is supplied to the endpoint? From host or generated locally?
> 
> From Host only, we don't support the separated clock model.
> 

OK. So even without refclk you are still able to access the controller
registers? So the controller CSRs should be accessible by separate local clock I
believe.

Anyhow, please add this limitation (refclk dependency from host) in commit
message.

[...]

> > > +	ret = phy_set_mode(stm32_pcie->phy, PHY_MODE_PCIE);
> > 
> > Hmm, so PHY mode is common for both endpoint and host?
> 
> Yes it is. We need to init the phy here because it is a clock source for the
> PCIe core clk
> 

Clock source? Is it coming directly to PCIe or through RCC? There is no direct
clock representation from PHY to PCIe in DT binding.

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 4/5] PCI: stm32: Add PCIe endpoint support for STM32MP25

[Christian Bruel]

On 12/16/24 17:17, Manivannan Sadhasivam wrote:
> On Mon, Dec 16, 2024 at 11:02:07AM +0100, Christian Bruel wrote:
>> Hi Manivanna,
>>
>> On 12/3/24 16:22, Manivannan Sadhasivam wrote:
>>> On Tue, Nov 26, 2024 at 04:51:18PM +0100, Christian Bruel wrote:
>>>
>>> [...]
>>>
>>>> +static int stm32_pcie_start_link(struct dw_pcie *pci)
>>>> +{
>>>> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
>>>> +	int ret;
>>>> +
>>>> +	if (stm32_pcie->link_status == STM32_PCIE_EP_LINK_ENABLED) {
>>>> +		dev_dbg(pci->dev, "Link is already enabled\n");
>>>> +		return 0;
>>>> +	}
>>>> +
>>>> +	ret = stm32_pcie_enable_link(pci);
>>>> +	if (ret) {
>>>> +		dev_err(pci->dev, "PCIe cannot establish link: %d\n", ret);
>>>> +		return ret;
>>>> +	}
>>>
>>> How the REFCLK is supplied to the endpoint? From host or generated locally?
>>
>>  From Host only, we don't support the separated clock model.
>>
> 
> OK. So even without refclk you are still able to access the controller
> registers? So the controller CSRs should be accessible by separate local clock I
> believe.
> 
> Anyhow, please add this limitation (refclk dependency from host) in commit
> message.
> 
> [...]
> 
>>>> +	ret = phy_set_mode(stm32_pcie->phy, PHY_MODE_PCIE);
>>>
>>> Hmm, so PHY mode is common for both endpoint and host?
>>
>> Yes it is. We need to init the phy here because it is a clock source for the
>> PCIe core clk
>>
> 
> Clock source? Is it coming directly to PCIe or through RCC? There is no direct
> clock representation from PHY to PCIe in DT binding.

The core_clk is generated directly by the PLL in the COMBOPHY, gated by 
the RCC

> 
> - Mani
> 

Re: [PATCH v2 1/5] dt-bindings: PCI: Add STM32MP25 PCIe root complex bindings

[Christian Bruel]

> Makes sense.  What about phys, resets, etc?  I'm pretty sure a PHY
> would be a per-Root Port thing, and some resets and wakeup signals
> also.
> 
> For new drivers, I think we should start adding Root Port stanzas to
> specifically associate those things with the Root Port, e.g.,
> something like this?
> 
>    pcie@48400000 {
>      compatible = "st,stm32mp25-pcie-rc";
> 
>      pcie@0,0 {
>        reg = <0x0000 0 0 0 0>;
>        phys = <&combophy PHY_TYPE_PCIE>;
>        phy-names = "pcie-phy";
>      };
>    };
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/pci/mediatek,mt7621-pcie.yaml?id=v6.12#n111
> is one binding that does this, others include apple,pcie.yaml,
> brcm,stb-pcie.yaml, hisilicon,kirin-pcie.yaml.
> 

On a second thought, moving the PHY to the root-port part would 
introduce a discrepancy with the pcie_ep binding, whereas the PHY is 
required on the pcie_ep node.

Even for the pcie_rc, the PHY is needed to enable the core_clk to access
the PCIe core registers,

So that would make 2 different required PHY locations for RC and EP:

     pcie_rc: pcie@48400000 {
       compatible = "st,stm32mp25-pcie-rc";

       pcie@0,0 {
         reg = <0x0000 0 0 0 0>;
         phys = <&combophy PHY_TYPE_PCIE>;
         phy-names = "pcie-phy";
       };
     };

     pcie_ep pcie@48400000 {
       compatible = "st,stm32mp25-pcie-ep";
       phys = <&combophy PHY_TYPE_PCIE>;
       phy-names = "pcie-phy";
     };

Simplest seems to keep the PHY required for the pcie core regardless of 
the mode and keep the empty root port to split the design

     pcie_rc: pcie@48400000 {
       compatible = "st,stm32mp25-pcie-rc";
       phys = <&combophy PHY_TYPE_PCIE>;
       phy-names = "pcie-phy";

         pcie@0,0 {
         reg = <0x0000 0 0 0 0>;
       };
     };

     pcie_ep: pcie@48400000 {
       compatible = "st,stm32mp25-pcie-ep";
       phys = <&combophy PHY_TYPE_PCIE>;
       phy-names = "pcie-phy";
     };

But I have no experience with multiple root-port systems, I'm open for 
the best :)

Thanks

Christian

Re: [PATCH v2 1/5] dt-bindings: PCI: Add STM32MP25 PCIe root complex bindings

[Manivannan Sadhasivam]

On Tue, Dec 03, 2024 at 04:25:15PM -0600, Bjorn Helgaas wrote:
> On Tue, Nov 26, 2024 at 04:51:15PM +0100, Christian Bruel wrote:
> > Document the bindings for STM32MP25 PCIe Controller configured in
> > root complex mode.
> > 
> > Supports 4 legacy interrupts and MSI interrupts from the ARM
> > GICv2m controller.
> 
> s/legacy/INTx/
> 
> > STM32 PCIe may be in a power domain which is the case for the STM32MP25
> > based boards.
> > 
> > Supports wake# from wake-gpios
> 
> s/wake#/WAKE#/
> 
> > +  wake-gpios:
> > +    description: GPIO controlled connection to WAKE# input signal
> 
> I'm not a hardware guy, but this sounds like a GPIO that *reads*
> WAKE#, not controls it.
> 
> > +    pcie@48400000 {
> > +        compatible = "st,stm32mp25-pcie-rc";
> > +        device_type = "pci";
> > +        num-lanes = <1>;
> 
> num-lanes applies to a Root Port, not to a Root Complex.  I know most
> bindings conflate Root Ports with the Root Complex, maybe because many
> of these controllers only support a single Root Port?
> 
> But are we ever going to separate these out?  I assume someday
> controllers will support multiple Root Ports and/or additional devices
> on the root bus, like RCiEPs, RCECs, etc., and we'll need per-RP phys,
> max-link-speed, num-lanes, reset-gpios, etc.
> 
> Seems like it would be to our benefit to split out the Root Ports when
> we can, even if the current hardware only supports one, so we can
> start untangling the code and data structures.
> 

+1 for moving the properties to RP node where they should belong to. The
controller driver might have to do some extra work to parse the RP node and get
these properties, but it is worth the effort.

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 1/5] dt-bindings: PCI: Add STM32MP25 PCIe root complex bindings

[Manivannan Sadhasivam]

On Tue, Dec 17, 2024 at 04:53:48PM +0100, Christian Bruel wrote:
> 
> > Makes sense.  What about phys, resets, etc?  I'm pretty sure a PHY
> > would be a per-Root Port thing, and some resets and wakeup signals
> > also.
> > 
> > For new drivers, I think we should start adding Root Port stanzas to
> > specifically associate those things with the Root Port, e.g.,
> > something like this?
> > 
> >    pcie@48400000 {
> >      compatible = "st,stm32mp25-pcie-rc";
> > 
> >      pcie@0,0 {
> >        reg = <0x0000 0 0 0 0>;
> >        phys = <&combophy PHY_TYPE_PCIE>;
> >        phy-names = "pcie-phy";
> >      };
> >    };
> > 
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/pci/mediatek,mt7621-pcie.yaml?id=v6.12#n111
> > is one binding that does this, others include apple,pcie.yaml,
> > brcm,stb-pcie.yaml, hisilicon,kirin-pcie.yaml.
> > 
> 
> On a second thought, moving the PHY to the root-port part would introduce a
> discrepancy with the pcie_ep binding, whereas the PHY is required on the
> pcie_ep node.
> 
> Even for the pcie_rc, the PHY is needed to enable the core_clk to access
> the PCIe core registers,
> 

But why that matters? You can still parse the child nodes, enable PHY and
configure PCIe registers.

> So that would make 2 different required PHY locations for RC and EP:
> 
>     pcie_rc: pcie@48400000 {
>       compatible = "st,stm32mp25-pcie-rc";
> 
>       pcie@0,0 {
>         reg = <0x0000 0 0 0 0>;
>         phys = <&combophy PHY_TYPE_PCIE>;
>         phy-names = "pcie-phy";
>       };
>     };
> 
>     pcie_ep pcie@48400000 {
>       compatible = "st,stm32mp25-pcie-ep";
>       phys = <&combophy PHY_TYPE_PCIE>;
>       phy-names = "pcie-phy";
>     };
> 
> Simplest seems to keep the PHY required for the pcie core regardless of the
> mode and keep the empty root port to split the design
> 

No please. Try to do the right thing from the start itself.

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 1/5] dt-bindings: PCI: Add STM32MP25 PCIe root complex bindings

[Christian Bruel]

On 12/17/24 18:25, Manivannan Sadhasivam wrote:
> On Tue, Dec 17, 2024 at 04:53:48PM +0100, Christian Bruel wrote:
>>
>>> Makes sense.  What about phys, resets, etc?  I'm pretty sure a PHY
>>> would be a per-Root Port thing, and some resets and wakeup signals
>>> also.
>>>
>>> For new drivers, I think we should start adding Root Port stanzas to
>>> specifically associate those things with the Root Port, e.g.,
>>> something like this?
>>>
>>>     pcie@48400000 {
>>>       compatible = "st,stm32mp25-pcie-rc";
>>>
>>>       pcie@0,0 {
>>>         reg = <0x0000 0 0 0 0>;
>>>         phys = <&combophy PHY_TYPE_PCIE>;
>>>         phy-names = "pcie-phy";
>>>       };
>>>     };
>>>
>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/pci/mediatek,mt7621-pcie.yaml?id=v6.12#n111
>>> is one binding that does this, others include apple,pcie.yaml,
>>> brcm,stb-pcie.yaml, hisilicon,kirin-pcie.yaml.
>>>
>>
>> On a second thought, moving the PHY to the root-port part would introduce a
>> discrepancy with the pcie_ep binding, whereas the PHY is required on the
>> pcie_ep node.
>>
>> Even for the pcie_rc, the PHY is needed to enable the core_clk to access
>> the PCIe core registers,
>>
> 
> But why that matters? You can still parse the child nodes, enable PHY and
> configure PCIe registers. >
>> So that would make 2 different required PHY locations for RC and EP:
>>
>>      pcie_rc: pcie@48400000 {
>>        compatible = "st,stm32mp25-pcie-rc";
>>
>>        pcie@0,0 {
>>          reg = <0x0000 0 0 0 0>;
>>          phys = <&combophy PHY_TYPE_PCIE>;
>>          phy-names = "pcie-phy";
>>        };
>>      };
>>
>>      pcie_ep pcie@48400000 {
>>        compatible = "st,stm32mp25-pcie-ep";
>>        phys = <&combophy PHY_TYPE_PCIE>;
>>        phy-names = "pcie-phy";
>>      };
>>
>> Simplest seems to keep the PHY required for the pcie core regardless of the
>> mode and keep the empty root port to split the design
>>
> 
> No please. Try to do the right thing from the start itself.

Parsing the child node to clock the IP seems weird. Note that 
hisilicon,kirin-pcie.yaml also declares the PHY at the controller level.

thanks

Christian




> 
> - Mani
> 

Re: [PATCH v2 1/5] dt-bindings: PCI: Add STM32MP25 PCIe root complex bindings

[Manivannan Sadhasivam]

On Wed, Dec 18, 2024 at 09:42:45AM +0100, Christian Bruel wrote:
> 
> 
> On 12/17/24 18:25, Manivannan Sadhasivam wrote:
> > On Tue, Dec 17, 2024 at 04:53:48PM +0100, Christian Bruel wrote:
> > > 
> > > > Makes sense.  What about phys, resets, etc?  I'm pretty sure a PHY
> > > > would be a per-Root Port thing, and some resets and wakeup signals
> > > > also.
> > > > 
> > > > For new drivers, I think we should start adding Root Port stanzas to
> > > > specifically associate those things with the Root Port, e.g.,
> > > > something like this?
> > > > 
> > > >     pcie@48400000 {
> > > >       compatible = "st,stm32mp25-pcie-rc";
> > > > 
> > > >       pcie@0,0 {
> > > >         reg = <0x0000 0 0 0 0>;
> > > >         phys = <&combophy PHY_TYPE_PCIE>;
> > > >         phy-names = "pcie-phy";
> > > >       };
> > > >     };
> > > > 
> > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/pci/mediatek,mt7621-pcie.yaml?id=v6.12#n111
> > > > is one binding that does this, others include apple,pcie.yaml,
> > > > brcm,stb-pcie.yaml, hisilicon,kirin-pcie.yaml.
> > > > 
> > > 
> > > On a second thought, moving the PHY to the root-port part would introduce a
> > > discrepancy with the pcie_ep binding, whereas the PHY is required on the
> > > pcie_ep node.
> > > 
> > > Even for the pcie_rc, the PHY is needed to enable the core_clk to access
> > > the PCIe core registers,
> > > 
> > 
> > But why that matters? You can still parse the child nodes, enable PHY and
> > configure PCIe registers. >
> > > So that would make 2 different required PHY locations for RC and EP:
> > > 
> > >      pcie_rc: pcie@48400000 {
> > >        compatible = "st,stm32mp25-pcie-rc";
> > > 
> > >        pcie@0,0 {
> > >          reg = <0x0000 0 0 0 0>;
> > >          phys = <&combophy PHY_TYPE_PCIE>;
> > >          phy-names = "pcie-phy";
> > >        };
> > >      };
> > > 
> > >      pcie_ep pcie@48400000 {
> > >        compatible = "st,stm32mp25-pcie-ep";
> > >        phys = <&combophy PHY_TYPE_PCIE>;
> > >        phy-names = "pcie-phy";
> > >      };
> > > 
> > > Simplest seems to keep the PHY required for the pcie core regardless of the
> > > mode and keep the empty root port to split the design
> > > 
> > 
> > No please. Try to do the right thing from the start itself.
> 
> Parsing the child node to clock the IP seems weird. Note that
> hisilicon,kirin-pcie.yaml also declares the PHY at the controller level.
> 

Nothing is weird here. Almost all multi port controller drivers does the same.
Most of the single port controller instances define port properties in
controller node only, but that's what we want to avoid now.

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 4/5] PCI: stm32: Add PCIe endpoint support for STM32MP25

[Manivannan Sadhasivam]

On Tue, Dec 17, 2024 at 10:48:43AM +0100, Christian Bruel wrote:
> 
> 
> On 12/16/24 17:17, Manivannan Sadhasivam wrote:
> > On Mon, Dec 16, 2024 at 11:02:07AM +0100, Christian Bruel wrote:
> > > Hi Manivanna,
> > > 
> > > On 12/3/24 16:22, Manivannan Sadhasivam wrote:
> > > > On Tue, Nov 26, 2024 at 04:51:18PM +0100, Christian Bruel wrote:
> > > > 
> > > > [...]
> > > > 
> > > > > +static int stm32_pcie_start_link(struct dw_pcie *pci)
> > > > > +{
> > > > > +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
> > > > > +	int ret;
> > > > > +
> > > > > +	if (stm32_pcie->link_status == STM32_PCIE_EP_LINK_ENABLED) {
> > > > > +		dev_dbg(pci->dev, "Link is already enabled\n");
> > > > > +		return 0;
> > > > > +	}
> > > > > +
> > > > > +	ret = stm32_pcie_enable_link(pci);
> > > > > +	if (ret) {
> > > > > +		dev_err(pci->dev, "PCIe cannot establish link: %d\n", ret);
> > > > > +		return ret;
> > > > > +	}
> > > > 
> > > > How the REFCLK is supplied to the endpoint? From host or generated locally?
> > > 
> > >  From Host only, we don't support the separated clock model.
> > > 
> > 
> > OK. So even without refclk you are still able to access the controller
> > registers? So the controller CSRs should be accessible by separate local clock I
> > believe.
> > 
> > Anyhow, please add this limitation (refclk dependency from host) in commit
> > message.
> > 
> > [...]
> > 
> > > > > +	ret = phy_set_mode(stm32_pcie->phy, PHY_MODE_PCIE);
> > > > 
> > > > Hmm, so PHY mode is common for both endpoint and host?
> > > 
> > > Yes it is. We need to init the phy here because it is a clock source for the
> > > PCIe core clk
> > > 
> > 
> > Clock source? Is it coming directly to PCIe or through RCC? There is no direct
> > clock representation from PHY to PCIe in DT binding.
> 
> The core_clk is generated directly by the PLL in the COMBOPHY, gated by the
> RCC
> 

In that case, phy should be the clock provider to RCC and PCIe should get the
gated clock it.

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 4/5] PCI: stm32: Add PCIe endpoint support for STM32MP25

[Christian Bruel]

On 12/18/24 10:08, Manivannan Sadhasivam wrote:
> On Tue, Dec 17, 2024 at 10:48:43AM +0100, Christian Bruel wrote:
>>
>>
>> On 12/16/24 17:17, Manivannan Sadhasivam wrote:
>>> On Mon, Dec 16, 2024 at 11:02:07AM +0100, Christian Bruel wrote:
>>>> Hi Manivanna,
>>>>
>>>> On 12/3/24 16:22, Manivannan Sadhasivam wrote:
>>>>> On Tue, Nov 26, 2024 at 04:51:18PM +0100, Christian Bruel wrote:
>>>>>
>>>>> [...]
>>>>>
>>>>>> +static int stm32_pcie_start_link(struct dw_pcie *pci)
>>>>>> +{
>>>>>> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
>>>>>> +	int ret;
>>>>>> +
>>>>>> +	if (stm32_pcie->link_status == STM32_PCIE_EP_LINK_ENABLED) {
>>>>>> +		dev_dbg(pci->dev, "Link is already enabled\n");
>>>>>> +		return 0;
>>>>>> +	}
>>>>>> +
>>>>>> +	ret = stm32_pcie_enable_link(pci);
>>>>>> +	if (ret) {
>>>>>> +		dev_err(pci->dev, "PCIe cannot establish link: %d\n", ret);
>>>>>> +		return ret;
>>>>>> +	}
>>>>>
>>>>> How the REFCLK is supplied to the endpoint? From host or generated locally?
>>>>
>>>>   From Host only, we don't support the separated clock model.
>>>>
>>>
>>> OK. So even without refclk you are still able to access the controller
>>> registers? So the controller CSRs should be accessible by separate local clock I
>>> believe.
>>>
>>> Anyhow, please add this limitation (refclk dependency from host) in commit
>>> message.
>>>
>>> [...]
>>>
>>>>>> +	ret = phy_set_mode(stm32_pcie->phy, PHY_MODE_PCIE);
>>>>>
>>>>> Hmm, so PHY mode is common for both endpoint and host?
>>>>
>>>> Yes it is. We need to init the phy here because it is a clock source for the
>>>> PCIe core clk
>>>>
>>>
>>> Clock source? Is it coming directly to PCIe or through RCC? There is no direct
>>> clock representation from PHY to PCIe in DT binding.
>>
>> The core_clk is generated directly by the PLL in the COMBOPHY, gated by the
>> RCC
>>
> 
> In that case, phy should be the clock provider to RCC and PCIe should get the
> gated clock it.

ok, seems sensible.



> 
> - Mani
> 

Re: [PATCH v2 2/5] PCI: stm32: Add PCIe host support for STM32MP25

[Manivannan Sadhasivam]

On Mon, Dec 16, 2024 at 10:00:27AM +0100, Christian Bruel wrote:

[...]

> > 
> > > +		msleep(PCIE_T_RRS_READY_MS);
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static void stm32_pcie_stop_link(struct dw_pcie *pci)
> > > +{
> > > +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
> > > +
> > > +	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
> > > +			   STM32MP25_PCIECR_LTSSM_EN, 0);
> > > +
> > > +	/* Assert PERST# */
> > > +	if (stm32_pcie->perst_gpio)
> > > +		gpiod_set_value(stm32_pcie->perst_gpio, 1);
> > 
> > I don't like tying PERST# handling with start/stop link. PERST# should be
> > handled based on the power/clock state.
> 
> I don't understand your point: We turn off the PHY in suspend_noirq(), so
> that seems a logical place to de-assert in resume_noirq after the refclk is
> ready. PERST# should be kept active until the PHY stablilizes the clock in
> resume. From the PCIe electromechanical specs, PERST# goes active while the
> refclk is not stable/
> 

While your understanding about PERST# is correct, your implementation is not.
You are toggling PERST# from start/stop link callbacks which are supposed to
control the LTSSM state only. I don't have issues with toggling PERST# in
stm32_pcie_{suspend/resume}_noirq().

> 
> > 
> > > +}
> > > +
> > > +static int stm32_pcie_suspend(struct device *dev)
> > > +{
> > > +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
> > > +
> > > +	if (device_may_wakeup(dev) || device_wakeup_path(dev))
> > > +		enable_irq_wake(stm32_pcie->wake_irq);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int stm32_pcie_resume(struct device *dev)
> > > +{
> > > +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
> > > +
> > > +	if (device_may_wakeup(dev) || device_wakeup_path(dev))
> > > +		disable_irq_wake(stm32_pcie->wake_irq);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int stm32_pcie_suspend_noirq(struct device *dev)
> > > +{
> > > +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
> > > +
> > > +	stm32_pcie->link_is_up = dw_pcie_link_up(stm32_pcie->pci);
> > > +
> > > +	stm32_pcie_stop_link(stm32_pcie->pci);
> > 
> > I don't understand how endpoint can wakeup the host if PERST# gets asserted.
> 
> The stm32 PCIe doesn't support L2, we don't expect an in-band beacon for the
> wakeup. We support wakeup only from sideband WAKE#, that will restart the
> link from IRQ
> 

I don't understand how WAKE# is supported without L2. Only in L2 state, endpoint
will make use of Vaux and it will wakeup the host using either beacon or WAKE#.
If you don't support L2, then the endpoint will reach L3 (link off) state.

> > 
> > > +	clk_disable_unprepare(stm32_pcie->clk);
> > > +
> > > +	if (!device_may_wakeup(dev) && !device_wakeup_path(dev))
> > > +		phy_exit(stm32_pcie->phy);
> > > +
> > > +	return pinctrl_pm_select_sleep_state(dev);
> > > +}
> > > +
> > > +static int stm32_pcie_resume_noirq(struct device *dev)
> > > +{
> > > +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
> > > +	struct dw_pcie *pci = stm32_pcie->pci;
> > > +	struct dw_pcie_rp *pp = &pci->pp;
> > > +	int ret;
> > > +
> > > +	/* init_state must be called first to force clk_req# gpio when no
> > 
> > CLKREQ#
> > 
> > Why RC should control CLKREQ#?
> 
> REFCLK is gated with CLKREQ#, So we cannot access the core
> without CLKREQ# if no device is present. So force it with a init pinmux
> the time to init the PHY and the core DBI registers
> 

Ok. You should add a comment to clarify it in the code as this is not a standard
behavior.

> > 
> > Also please use preferred style for multi-line comments:
> > 
> > 	/*
> > 	 * ...
> > 	 */
> > 
> > > +	 * device is plugged.
> > > +	 */
> > > +	if (!IS_ERR(dev->pins->init_state))
> > > +		ret = pinctrl_select_state(dev->pins->p, dev->pins->init_state);
> > > +	else
> > > +		ret = pinctrl_pm_select_default_state(dev);
> > > +
> > > +	if (ret) {
> > > +		dev_err(dev, "Failed to activate pinctrl pm state: %d\n", ret);
> > > +		return ret;
> > > +	}
> > > +
> > > +	if (!device_may_wakeup(dev) && !device_wakeup_path(dev)) {
> > > +		ret = phy_init(stm32_pcie->phy);
> > > +		if (ret) {
> > > +			pinctrl_pm_select_default_state(dev);
> > > +			return ret;
> > > +		}
> > > +	}
> > > +
> > > +	ret = clk_prepare_enable(stm32_pcie->clk);
> > > +	if (ret)
> > > +		goto clk_err;
> > 
> > Please name the goto labels of their purpose. Like err_phy_exit.
> 
> OK
> 
> > 
> > > +
> > > +	ret = dw_pcie_setup_rc(pp);
> > > +	if (ret)
> > > +		goto pcie_err;
> > 
> > This should be, 'err_disable_clk'.
> > 
> > > +
> > > +	if (stm32_pcie->link_is_up) {
> > 
> > Why do you need this check? You cannot start the link in the absence of an
> > endpoint?
> > 
> 
> It is an optimization to avoid unnecessary "dw_pcie_wait_for_link" if no
> device is present during suspend
> 

In that case you'll not trigger LTSSM if there was no endpoint connected before
suspend. What if users connect an endpoint after resume?

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 2/5] PCI: stm32: Add PCIe host support for STM32MP25

[Christian Bruel]

On 12/18/24 10:46, Manivannan Sadhasivam wrote:
> On Mon, Dec 16, 2024 at 10:00:27AM +0100, Christian Bruel wrote:
> 
> [...]
> 
>>>
>>>> +		msleep(PCIE_T_RRS_READY_MS);
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +
>>>> +static void stm32_pcie_stop_link(struct dw_pcie *pci)
>>>> +{
>>>> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
>>>> +
>>>> +	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
>>>> +			   STM32MP25_PCIECR_LTSSM_EN, 0);
>>>> +
>>>> +	/* Assert PERST# */
>>>> +	if (stm32_pcie->perst_gpio)
>>>> +		gpiod_set_value(stm32_pcie->perst_gpio, 1);
>>>
>>> I don't like tying PERST# handling with start/stop link. PERST# should be
>>> handled based on the power/clock state.
>>
>> I don't understand your point: We turn off the PHY in suspend_noirq(), so
>> that seems a logical place to de-assert in resume_noirq after the refclk is
>> ready. PERST# should be kept active until the PHY stablilizes the clock in
>> resume. From the PCIe electromechanical specs, PERST# goes active while the
>> refclk is not stable/
>>
> 
> While your understanding about PERST# is correct, your implementation is not.
> You are toggling PERST# from start/stop link callbacks which are supposed to
> control the LTSSM state only. I don't have issues with toggling PERST# in
> stm32_pcie_{suspend/resume}_noirq().

Ah OK. this function is split now into 2 functional blocks in the 
upcoming version

> 
>>
>>>
>>>> +}
>>>> +
>>>> +static int stm32_pcie_suspend(struct device *dev)
>>>> +{
>>>> +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
>>>> +
>>>> +	if (device_may_wakeup(dev) || device_wakeup_path(dev))
>>>> +		enable_irq_wake(stm32_pcie->wake_irq);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int stm32_pcie_resume(struct device *dev)
>>>> +{
>>>> +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
>>>> +
>>>> +	if (device_may_wakeup(dev) || device_wakeup_path(dev))
>>>> +		disable_irq_wake(stm32_pcie->wake_irq);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int stm32_pcie_suspend_noirq(struct device *dev)
>>>> +{
>>>> +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
>>>> +
>>>> +	stm32_pcie->link_is_up = dw_pcie_link_up(stm32_pcie->pci);
>>>> +
>>>> +	stm32_pcie_stop_link(stm32_pcie->pci);
>>>
>>> I don't understand how endpoint can wakeup the host if PERST# gets asserted.
>>
>> The stm32 PCIe doesn't support L2, we don't expect an in-band beacon for the
>> wakeup. We support wakeup only from sideband WAKE#, that will restart the
>> link from IRQ
>>
> 
> I don't understand how WAKE# is supported without L2. Only in L2 state, endpoint
> will make use of Vaux and it will wakeup the host using either beacon or WAKE#.
> If you don't support L2, then the endpoint will reach L3 (link off) state.

I think this is what happens, my understanding is that the device is 
still powered to get the wakeup event (eg WoL magic packet), triggers 
the PCIe wake_IRQ from the WAKE#.

> 
>>>
>>>> +	clk_disable_unprepare(stm32_pcie->clk);
>>>> +
>>>> +	if (!device_may_wakeup(dev) && !device_wakeup_path(dev))
>>>> +		phy_exit(stm32_pcie->phy);
>>>> +
>>>> +	return pinctrl_pm_select_sleep_state(dev);
>>>> +}
>>>> +
>>>> +static int stm32_pcie_resume_noirq(struct device *dev)
>>>> +{
>>>> +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
>>>> +	struct dw_pcie *pci = stm32_pcie->pci;
>>>> +	struct dw_pcie_rp *pp = &pci->pp;
>>>> +	int ret;
>>>> +
>>>> +	/* init_state must be called first to force clk_req# gpio when no
>>>
>>> CLKREQ#
>>>
>>> Why RC should control CLKREQ#?
>>
>> REFCLK is gated with CLKREQ#, So we cannot access the core
>> without CLKREQ# if no device is present. So force it with a init pinmux
>> the time to init the PHY and the core DBI registers
>>
> 
> Ok. You should add a comment to clarify it in the code as this is not a standard
> behavior.
> 

OK

>>>
>>> Also please use preferred style for multi-line comments:
>>>
>>> 	/*
>>> 	 * ...
>>> 	 */
>>>
>>>> +	 * device is plugged.
>>>> +	 */
>>>> +	if (!IS_ERR(dev->pins->init_state))
>>>> +		ret = pinctrl_select_state(dev->pins->p, dev->pins->init_state);
>>>> +	else
>>>> +		ret = pinctrl_pm_select_default_state(dev);
>>>> +
>>>> +	if (ret) {
>>>> +		dev_err(dev, "Failed to activate pinctrl pm state: %d\n", ret);
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	if (!device_may_wakeup(dev) && !device_wakeup_path(dev)) {
>>>> +		ret = phy_init(stm32_pcie->phy);
>>>> +		if (ret) {
>>>> +			pinctrl_pm_select_default_state(dev);
>>>> +			return ret;
>>>> +		}
>>>> +	}
>>>> +
>>>> +	ret = clk_prepare_enable(stm32_pcie->clk);
>>>> +	if (ret)
>>>> +		goto clk_err;
>>>
>>> Please name the goto labels of their purpose. Like err_phy_exit.
>>
>> OK
>>
>>>
>>>> +
>>>> +	ret = dw_pcie_setup_rc(pp);
>>>> +	if (ret)
>>>> +		goto pcie_err;
>>>
>>> This should be, 'err_disable_clk'.
>>>
>>>> +
>>>> +	if (stm32_pcie->link_is_up) {
>>>
>>> Why do you need this check? You cannot start the link in the absence of an
>>> endpoint?
>>>
>>
>> It is an optimization to avoid unnecessary "dw_pcie_wait_for_link" if no
>> device is present during suspend
>>
> 
> In that case you'll not trigger LTSSM if there was no endpoint connected before
> suspend. What if users connect an endpoint after resume?

Yes, exactly. We don't support hotplug, and plugging a device while the 
system is in stand-by is something that we don't expect. The imx6 
platform does this also.

thanks,

Christian

> 
> - Mani
> 

Re: [PATCH v2 2/5] PCI: stm32: Add PCIe host support for STM32MP25

[Manivannan Sadhasivam]

On Wed, Dec 18, 2024 at 12:24:21PM +0100, Christian Bruel wrote:

[...]

> > > > > +static int stm32_pcie_suspend_noirq(struct device *dev)
> > > > > +{
> > > > > +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
> > > > > +
> > > > > +	stm32_pcie->link_is_up = dw_pcie_link_up(stm32_pcie->pci);
> > > > > +
> > > > > +	stm32_pcie_stop_link(stm32_pcie->pci);
> > > > 
> > > > I don't understand how endpoint can wakeup the host if PERST# gets asserted.
> > > 
> > > The stm32 PCIe doesn't support L2, we don't expect an in-band beacon for the
> > > wakeup. We support wakeup only from sideband WAKE#, that will restart the
> > > link from IRQ
> > > 
> > 
> > I don't understand how WAKE# is supported without L2. Only in L2 state, endpoint
> > will make use of Vaux and it will wakeup the host using either beacon or WAKE#.
> > If you don't support L2, then the endpoint will reach L3 (link off) state.
> 
> I think this is what happens, my understanding is that the device is still
> powered to get the wakeup event (eg WoL magic packet), triggers the PCIe
> wake_IRQ from the WAKE#.
> 

Honestly, I still cannot understand how this can happen.

> > 
> > > > 
> > > > > +	clk_disable_unprepare(stm32_pcie->clk);
> > > > > +
> > > > > +	if (!device_may_wakeup(dev) && !device_wakeup_path(dev))
> > > > > +		phy_exit(stm32_pcie->phy);
> > > > > +
> > > > > +	return pinctrl_pm_select_sleep_state(dev);
> > > > > +}
> > > > > +
> > > > > +static int stm32_pcie_resume_noirq(struct device *dev)
> > > > > +{
> > > > > +	struct stm32_pcie *stm32_pcie = dev_get_drvdata(dev);
> > > > > +	struct dw_pcie *pci = stm32_pcie->pci;
> > > > > +	struct dw_pcie_rp *pp = &pci->pp;
> > > > > +	int ret;
> > > > > +
> > > > > +	/* init_state must be called first to force clk_req# gpio when no
> > > > 
> > > > CLKREQ#
> > > > 
> > > > Why RC should control CLKREQ#?
> > > 
> > > REFCLK is gated with CLKREQ#, So we cannot access the core
> > > without CLKREQ# if no device is present. So force it with a init pinmux
> > > the time to init the PHY and the core DBI registers
> > > 
> > 
> > Ok. You should add a comment to clarify it in the code as this is not a standard
> > behavior.
> > 
> 
> OK
> 
> > > > 
> > > > Also please use preferred style for multi-line comments:
> > > > 
> > > > 	/*
> > > > 	 * ...
> > > > 	 */
> > > > 
> > > > > +	 * device is plugged.
> > > > > +	 */
> > > > > +	if (!IS_ERR(dev->pins->init_state))
> > > > > +		ret = pinctrl_select_state(dev->pins->p, dev->pins->init_state);
> > > > > +	else
> > > > > +		ret = pinctrl_pm_select_default_state(dev);
> > > > > +
> > > > > +	if (ret) {
> > > > > +		dev_err(dev, "Failed to activate pinctrl pm state: %d\n", ret);
> > > > > +		return ret;
> > > > > +	}
> > > > > +
> > > > > +	if (!device_may_wakeup(dev) && !device_wakeup_path(dev)) {
> > > > > +		ret = phy_init(stm32_pcie->phy);
> > > > > +		if (ret) {
> > > > > +			pinctrl_pm_select_default_state(dev);
> > > > > +			return ret;
> > > > > +		}
> > > > > +	}
> > > > > +
> > > > > +	ret = clk_prepare_enable(stm32_pcie->clk);
> > > > > +	if (ret)
> > > > > +		goto clk_err;
> > > > 
> > > > Please name the goto labels of their purpose. Like err_phy_exit.
> > > 
> > > OK
> > > 
> > > > 
> > > > > +
> > > > > +	ret = dw_pcie_setup_rc(pp);
> > > > > +	if (ret)
> > > > > +		goto pcie_err;
> > > > 
> > > > This should be, 'err_disable_clk'.
> > > > 
> > > > > +
> > > > > +	if (stm32_pcie->link_is_up) {
> > > > 
> > > > Why do you need this check? You cannot start the link in the absence of an
> > > > endpoint?
> > > > 
> > > 
> > > It is an optimization to avoid unnecessary "dw_pcie_wait_for_link" if no
> > > device is present during suspend
> > > 
> > 
> > In that case you'll not trigger LTSSM if there was no endpoint connected before
> > suspend. What if users connect an endpoint after resume?
> 
> Yes, exactly. We don't support hotplug, and plugging a device while the
> system is in stand-by is something that we don't expect. The imx6 platform
> does this also.
> 

You should reconsider this approach. You'll never know how the OEMs are going to
use the PCIe slot. And lack of standard hotplug is not preventing users from
doing hotplug (they could try to do rescan themselves etc...)

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 4/5] PCI: stm32: Add PCIe endpoint support for STM32MP25

[Christian Bruel]

Hi Mani,

On 12/3/24 16:22, Manivannan Sadhasivam wrote:
> On Tue, Nov 26, 2024 at 04:51:18PM +0100, Christian Bruel wrote:
> 
> [...]
> 
>> +static int stm32_pcie_start_link(struct dw_pcie *pci)
>> +{
>> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
>> +	int ret;
>> +
>> +	if (stm32_pcie->link_status == STM32_PCIE_EP_LINK_ENABLED) {
>> +		dev_dbg(pci->dev, "Link is already enabled\n");
>> +		return 0;
>> +	}
>> +
>> +	ret = stm32_pcie_enable_link(pci);
>> +	if (ret) {
>> +		dev_err(pci->dev, "PCIe cannot establish link: %d\n", ret);
>> +		return ret;
>> +	}
> 
> How the REFCLK is supplied to the endpoint? From host or generated locally?

The REFCLK is supplied from the host, it does not support separated clocks
> 
>> +
>> +	stm32_pcie->link_status = STM32_PCIE_EP_LINK_ENABLED;
>> +
>> +	enable_irq(stm32_pcie->perst_irq);
>> +
>> +	return 0;
>> +}
>> +
>> +static void stm32_pcie_stop_link(struct dw_pcie *pci)
>> +{
>> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
>> +
>> +	if (stm32_pcie->link_status == STM32_PCIE_EP_LINK_DISABLED) {
>> +		dev_dbg(pci->dev, "Link is already disabled\n");
>> +		return;
>> +	}
>> +
>> +	disable_irq(stm32_pcie->perst_irq);
>> +
>> +	stm32_pcie_disable_link(pci);
>> +
>> +	stm32_pcie->link_status = STM32_PCIE_EP_LINK_DISABLED;
>> +}
>> +
>> +static int stm32_pcie_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
>> +				unsigned int type, u16 interrupt_num)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>> +
>> +	switch (type) {
>> +	case PCI_IRQ_INTX:
>> +		return dw_pcie_ep_raise_intx_irq(ep, func_no);
>> +	case PCI_IRQ_MSI:
>> +		return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
>> +	default:
>> +		dev_err(pci->dev, "UNKNOWN IRQ type\n");
>> +		return -EINVAL;
>> +	}
>> +}
>> +
>> +static const struct pci_epc_features stm32_pcie_epc_features = {
>> +	.msi_capable = true,
>> +	.align = 1 << 16,
> 
> Use SZ_64K
> 
>> +};
>> +
> 
> [...]
> 
>> +static int stm32_add_pcie_ep(struct stm32_pcie *stm32_pcie,
>> +			     struct platform_device *pdev)
>> +{
>> +	struct dw_pcie *pci = stm32_pcie->pci;
>> +	struct dw_pcie_ep *ep = &pci->ep;
>> +	struct device *dev = &pdev->dev;
>> +	int ret;
>> +
>> +	ret = regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
>> +				 STM32MP25_PCIECR_TYPE_MASK,
>> +				 STM32MP25_PCIECR_EP);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = pm_runtime_resume_and_get(dev);
>> +	if (ret < 0) {
>> +		dev_err(dev, "pm runtime resume failed: %d\n", ret);
>> +		return ret;
>> +	}
> 
> You might want to do runtime resume before accessing regmap.

ok

> 
>> +
>> +	reset_control_assert(stm32_pcie->rst);
>> +	reset_control_deassert(stm32_pcie->rst);
>> +
>> +	ep->ops = &stm32_pcie_ep_ops;
>> +
>> +	ret = dw_pcie_ep_init(ep);
>> +	if (ret) {
>> +		dev_err(dev, "failed to initialize ep: %d\n", ret);
>> +		goto err_init;
>> +	}
>> +
>> +	ret = stm32_pcie_enable_resources(stm32_pcie);
>> +	if (ret) {
>> +		dev_err(dev, "failed to enable resources: %d\n", ret);
>> +		goto err_clk;
>> +	}
>> +
>> +	ret = dw_pcie_ep_init_registers(ep);
>> +	if (ret) {
>> +		dev_err(dev, "Failed to initialize DWC endpoint registers\n");
>> +		goto err_init_regs;
>> +	}
>> +
>> +	pci_epc_init_notify(ep->epc);
>> +
>> +	return 0;
>> +
>> +err_init_regs:
>> +	stm32_pcie_disable_resources(stm32_pcie);
>> +
>> +err_clk:
>> +	dw_pcie_ep_deinit(ep);
>> +
>> +err_init:
>> +	pm_runtime_put_sync(dev);
>> +	return ret;
>> +}
>> +
>> +static int stm32_pcie_probe(struct platform_device *pdev)
>> +{
>> +	struct stm32_pcie *stm32_pcie;
>> +	struct dw_pcie *dw;
>> +	struct device *dev = &pdev->dev;
>> +	int ret;
>> +
>> +	stm32_pcie = devm_kzalloc(dev, sizeof(*stm32_pcie), GFP_KERNEL);
>> +	if (!stm32_pcie)
>> +		return -ENOMEM;
>> +
>> +	dw = devm_kzalloc(dev, sizeof(*dw), GFP_KERNEL);
>> +	if (!dw)
>> +		return -ENOMEM;
> 
> Why can't you allocate it statically inside 'struct stm32_pcie'?
> 

will do, as for the rc

>> +
>> +	stm32_pcie->pci = dw;
>> +
>> +	dw->dev = dev;
>> +	dw->ops = &dw_pcie_ops;
>> +
>> +	stm32_pcie->regmap = syscon_regmap_lookup_by_compatible("st,stm32mp25-syscfg");
>> +	if (IS_ERR(stm32_pcie->regmap))
>> +		return dev_err_probe(dev, PTR_ERR(stm32_pcie->regmap),
>> +				     "No syscfg specified\n");
>> +
>> +	stm32_pcie->phy = devm_phy_get(dev, "pcie-phy");
>> +	if (IS_ERR(stm32_pcie->phy))
>> +		return dev_err_probe(dev, PTR_ERR(stm32_pcie->phy),
>> +				     "failed to get pcie-phy\n");
>> +
>> +	stm32_pcie->clk = devm_clk_get(dev, NULL);
>> +	if (IS_ERR(stm32_pcie->clk))
>> +		return dev_err_probe(dev, PTR_ERR(stm32_pcie->clk),
>> +				     "Failed to get PCIe clock source\n");
>> +
>> +	stm32_pcie->rst = devm_reset_control_get_exclusive(dev, NULL);
>> +	if (IS_ERR(stm32_pcie->rst))
>> +		return dev_err_probe(dev, PTR_ERR(stm32_pcie->rst),
>> +				     "Failed to get PCIe reset\n");
>> +
>> +	stm32_pcie->perst_gpio = devm_gpiod_get(dev, "reset", GPIOD_IN);
>> between PCIE and USB3+	if (IS_ERR(stm32_pcie->perst_gpio))
>> +		return dev_err_probe(dev, PTR_ERR(stm32_pcie->perst_gpio),
>> +				     "Failed to get reset GPIO\n");
>> +
>> +	ret = phy_set_mode(stm32_pcie->phy, PHY_MODE_PCIE);
> 
> Hmm, so PHY mode is common for both endpoint and host?

the COMBOPHY MODESEL sysconf takes PCIE or USB3 as value
> 
> - Mani
> 

Re: [PATCH v2 4/5] PCI: stm32: Add PCIe endpoint support for STM32MP25

[Christian Bruel]

On 12/16/24 17:17, Manivannan Sadhasivam wrote:
> On Mon, Dec 16, 2024 at 11:02:07AM +0100, Christian Bruel wrote:
>> Hi Manivanna,
>>
>> On 12/3/24 16:22, Manivannan Sadhasivam wrote:
>>> On Tue, Nov 26, 2024 at 04:51:18PM +0100, Christian Bruel wrote:
>>>
>>> [...]
>>>
>>>> +static int stm32_pcie_start_link(struct dw_pcie *pci)
>>>> +{
>>>> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
>>>> +	int ret;
>>>> +
>>>> +	if (stm32_pcie->link_status == STM32_PCIE_EP_LINK_ENABLED) {
>>>> +		dev_dbg(pci->dev, "Link is already enabled\n");
>>>> +		return 0;
>>>> +	}
>>>> +
>>>> +	ret = stm32_pcie_enable_link(pci);
>>>> +	if (ret) {
>>>> +		dev_err(pci->dev, "PCIe cannot establish link: %d\n", ret);
>>>> +		return ret;
>>>> +	}
>>>
>>> How the REFCLK is supplied to the endpoint? From host or generated locally?
>>
>>  From Host only, we don't support the separated clock model.
>>
> 
> OK. So even without refclk you are still able to access the controller
> registers? So the controller CSRs should be accessible by separate local clock I
> believe.
> 
> Anyhow, please add this limitation (refclk dependency from host) in commit
> message.
> 
> [...]
> 
>>>> +	ret = phy_set_mode(stm32_pcie->phy, PHY_MODE_PCIE);
>>>
>>> Hmm, so PHY mode is common for both endpoint and host?
>>
>> Yes it is. We need to init the phy here because it is a clock source for the
>> PCIe core clk
>>
> 
> Clock source? Is it coming directly to PCIe or through RCC? There is no direct
> clock representation from PHY to PCIe in DT binding.

We have the following simplified clock dependencies (details in the RM)

                                 _____________
RCC  ck_icn_pcie--- ------------|-> dbi_clk  |
                     _________   |            |
      ck_icn_phy ---|->       |  |            |
                    |  pipe0--|--|->core_clk  |
      ck_ker ----- -|->       |  |            |
                    |         |  |            |
      100mhz pad ---|-> pll   |  |            |
                    |_________|  |____________|
                      COMBOPHY      PCIE


I considered adding the COMBOPHY pipe0 as the clock provider for the 
PCIe core_clk, but this did not provide any advantage since the PLL 
needs to be locked first and all settings need to be completed. 
Therefore, using clock_prepare_enable(pipe0) would be redundant with 
what phy_init already accomplishes. The phy_init function is necessary 
because it is used by the USB3 driver.

Since the core_clk is operational when all three other clocks are 
enabled and the PLL is locked, modeling pipe0 had minimal value, 
especially considering the dependencies of the USB3 driver.

I will add a comment in the code to explain this.

> 
> - Mani
> 

Re: [PATCH v2 4/5] PCI: stm32: Add PCIe endpoint support for STM32MP25

[Christian Bruel]

On 12/5/24 18:27, Bjorn Helgaas wrote:
> On Tue, Nov 26, 2024 at 04:51:18PM +0100, Christian Bruel wrote:

>> +static void stm32_pcie_ep_init(struct dw_pcie_ep *ep)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
>> +	enum pci_barno bar;
>> +
>> +	for (bar = 0; bar < PCI_STD_NUM_BARS; bar++)
>> +		dw_pcie_ep_reset_bar(pci, bar);
>> +
>> +	/* Defer Completion Requests until link started */
> 
> I asked about this before [1] but didn't finish the conversation.  My
> main point is that I think "Completion Request" is a misnomer.
> There's a "Configuration Request" and a "Completion," but no such
> thing as a "Completion Request."
> 
> Based on your previous response, I think this should say something
> like "respond to config requests with Request Retry Status (RRS) until
> we're prepared to handle them."
> 
>> +	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
>> +			   STM32MP25_PCIECR_REQ_RETRY_EN,
>> +			   STM32MP25_PCIECR_REQ_RETRY_EN);
>> +}
>> +
>> +static int stm32_pcie_enable_link(struct dw_pcie *pci)
>> +{
>> +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
>> +	int ret;
>> +
>> +	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
>> +			   STM32MP25_PCIECR_LTSSM_EN,
>> +			   STM32MP25_PCIECR_LTSSM_EN);
>> +
>> +	ret = dw_pcie_wait_for_link(pci);
>> +	if (ret)
>> +		return ret;
>> +
>> +	regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR,
>> +			   STM32MP25_PCIECR_REQ_RETRY_EN,
>> +			   0);
> 
> And I assume this means the endpoint will accept config requests and
> handle them normally instead of responding with RRS.
> 
> Strictly speaking this is a different condition than "the link is up"
> because the link must be up in order to even receive a config request.
> The purpose of RRS is for devices that need more initialization time
> after the link is up before they can respond to config requests.
> 
> The fact that the hardware provides this bit makes me think the
> designer anticipated that the link might come up before the rest of
> the device is fully initialized.

You are correct and I am unable to reproduce a scenario where this is 
still required.

Upon reviewing the history, I initially implemented this to address a 
dependency issue in the original code, where enable_link was invoked 
prematurely following the deassertion of PERST, as soon as the host was 
ready but before the device configuration space was initialized, so host 
enumeration was wrong.

Since then, the perst_irq is enabled by start_link. Consequently, the 
initialization, enable_link, and enumeration sequence is now correct

This bit is useless and can be dropped

Thank you for identifying it.

Christian

> 
> Bjorn
> 
> [1] https://lore.kernel.org/r/20241112203846.GA1856246@bhelgaas
> 

Re: [PATCH v2 4/5] PCI: stm32: Add PCIe endpoint support for STM32MP25

[Bjorn Helgaas]

On Mon, Dec 16, 2024 at 03:00:58PM +0100, Christian Bruel wrote:
> On 12/5/24 18:27, Bjorn Helgaas wrote:
> > On Tue, Nov 26, 2024 at 04:51:18PM +0100, Christian Bruel wrote:
> > > Add driver to configure the STM32MP25 SoC PCIe Gen2 controller based on the
> > > DesignWare PCIe core in endpoint mode.

> > > +static void stm32_pcie_ep_init(struct dw_pcie_ep *ep)
> > > +{
> > > +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > > +	struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci);
> > > +	enum pci_barno bar;
> > > +
> > > +	for (bar = 0; bar < PCI_STD_NUM_BARS; bar++)
> > > +		dw_pcie_ep_reset_bar(pci, bar);
> > > +
> > > +	/* Defer Completion Requests until link started */
> > 
> > I asked about this before [1] but didn't finish the conversation.  My
> > main point is that I think "Completion Request" is a misnomer.
> > There's a "Configuration Request" and a "Completion," but no such
> > thing as a "Completion Request."
> > 
> > Based on your previous response, I think this should say something
> > like "respond to config requests with Request Retry Status (RRS) until
> > we're prepared to handle them."
> 
> OK thanks for the phrasing. This is inline with the DWC doc:
> "... controller completes incoming configuration requests with a
> configuration request retry status."
> The only thing is that the PCIe specs talks about CRS, not RRS.
> 
> so slightly change to
> "respond to config requests with Configuration Request Retry Status (CRS)
> until we're prepared to handle them."

This terminology between PCIe r5.0 and r6.0.  In r5.0, sec 2.2.9
labels Completion Status value 010b as "Configuration Request Retry
Status (CRS)", but in r6.0, sec 2.2.9.1 labels that same value as
"Request Retry Status (RRS)".

We changed most usage inside drivers/pci/ to align with the r6.0 term
with https://git.kernel.org/linus/87f10faf166a ("PCI: Rename CRS
Completion Status to RRS").

But with respect to this patch, changing "Completion Request" to
"Configuration Request" is the main thing.

Bjorn