Merge branch 'pci/controller/sophgo'

- Check for existence of struct cdns_pcie.ops before using it to allow
  Cadence drivers that don't need to supply ops (Chen Wang)

- Add DT binding and driver for the Sophgo SG2042 PCIe controller (Chen
  Wang)

* pci/controller/sophgo:
  PCI: sg2042: Add Sophgo SG2042 PCIe driver
  PCI: cadence: Check for the existence of cdns_pcie::ops before using it
  dt-bindings: pci: Add Sophgo SG2042 PCIe host

Documentation/devicetree/bindings/pci/sophgo,sg2042-pcie-host.yaml

@@ -0,0 +1,64 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pci/sophgo,sg2042-pcie-host.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sophgo SG2042 PCIe Host (Cadence PCIe Wrapper)
+
+description:
+  Sophgo SG2042 PCIe host controller is based on the Cadence PCIe core.
+
+maintainers:
+  - Chen Wang <unicorn_wang@outlook.com>
+
+properties:
+  compatible:
+    const: sophgo,sg2042-pcie-host
+
+  reg:
+    maxItems: 2
+
+  reg-names:
+    items:
+      - const: reg
+      - const: cfg
+
+  vendor-id:
+    const: 0x1f1c
+
+  device-id:
+    const: 0x2042
+
+  msi-parent: true
+
+allOf:
+  - $ref: cdns-pcie-host.yaml#
+
+required:
+  - compatible
+  - reg
+  - reg-names
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    pcie@62000000 {
+      compatible = "sophgo,sg2042-pcie-host";
+      device_type = "pci";
+      reg = <0x62000000  0x00800000>,
+            <0x48000000  0x00001000>;
+      reg-names = "reg", "cfg";
+      #address-cells = <3>;
+      #size-cells = <2>;
+      ranges = <0x81000000 0 0x00000000 0xde000000 0 0x00010000>,
+               <0x82000000 0 0xd0400000 0xd0400000 0 0x0d000000>;
+      bus-range = <0x00 0xff>;
+      vendor-id = <0x1f1c>;
+      device-id = <0x2042>;
+      cdns,no-bar-match-nbits = <48>;
+      msi-parent = <&msi>;
+    };

drivers/pci/controller/cadence/Kconfig

@@ -42,6 +42,15 @@ config PCIE_CADENCE_PLAT_EP
 	  endpoint mode. This PCIe controller may be embedded into many
 	  different vendors SoCs.
 
+config PCIE_SG2042_HOST
+	tristate "Sophgo SG2042 PCIe controller (host mode)"
+	depends on OF && (ARCH_SOPHGO || COMPILE_TEST)
+	select PCIE_CADENCE_HOST
+	help
+	  Say Y here if you want to support the Sophgo SG2042 PCIe platform
+	  controller in host mode. Sophgo SG2042 PCIe controller uses Cadence
+	  PCIe core.
+
 config PCI_J721E
 	tristate
 	select PCIE_CADENCE_HOST if PCI_J721E_HOST != n
@@ -67,4 +76,5 @@ config PCI_J721E_EP
 	  Say Y here if you want to support the TI J721E PCIe platform
 	  controller in endpoint mode. TI J721E PCIe controller uses Cadence PCIe
 	  core.
+
 endmenu

drivers/pci/controller/cadence/Makefile

@@ -4,3 +4,4 @@ obj-$(CONFIG_PCIE_CADENCE_HOST) += pcie-cadence-host.o
 obj-$(CONFIG_PCIE_CADENCE_EP) += pcie-cadence-ep.o
 obj-$(CONFIG_PCIE_CADENCE_PLAT) += pcie-cadence-plat.o
 obj-$(CONFIG_PCI_J721E) += pci-j721e.o
+obj-$(CONFIG_PCIE_SG2042_HOST) += pcie-sg2042.o

drivers/pci/controller/cadence/pcie-cadence-host.c

@@ -531,7 +531,7 @@ static int cdns_pcie_host_init_address_translation(struct cdns_pcie_rc *rc)
 	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(0), addr1);
 	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(0), desc1);
 
-	if (pcie->ops->cpu_addr_fixup)
+	if (pcie->ops && pcie->ops->cpu_addr_fixup)
 		cpu_addr = pcie->ops->cpu_addr_fixup(pcie, cpu_addr);
 
 	addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(12) |

drivers/pci/controller/cadence/pcie-cadence.c

@@ -106,7 +106,7 @@ void cdns_pcie_set_outbound_region(struct cdns_pcie *pcie, u8 busnr, u8 fn,
 	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(r), desc1);
 
 	/* Set the CPU address */
-	if (pcie->ops->cpu_addr_fixup)
+	if (pcie->ops && pcie->ops->cpu_addr_fixup)
 		cpu_addr = pcie->ops->cpu_addr_fixup(pcie, cpu_addr);
 
 	addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(nbits) |
@@ -137,7 +137,7 @@ void cdns_pcie_set_outbound_region_for_normal_msg(struct cdns_pcie *pcie,
 	}
 
 	/* Set the CPU address */
-	if (pcie->ops->cpu_addr_fixup)
+	if (pcie->ops && pcie->ops->cpu_addr_fixup)
 		cpu_addr = pcie->ops->cpu_addr_fixup(pcie, cpu_addr);
 
 	addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(17) |

drivers/pci/controller/cadence/pcie-cadence.h

@@ -494,7 +494,7 @@ static inline u32 cdns_pcie_ep_fn_readl(struct cdns_pcie *pcie, u8 fn, u32 reg)
 
 static inline int cdns_pcie_start_link(struct cdns_pcie *pcie)
 {
-	if (pcie->ops->start_link)
+	if (pcie->ops && pcie->ops->start_link)
 		return pcie->ops->start_link(pcie);
 
 	return 0;
@@ -502,13 +502,13 @@ static inline int cdns_pcie_start_link(struct cdns_pcie *pcie)
 
 static inline void cdns_pcie_stop_link(struct cdns_pcie *pcie)
 {
-	if (pcie->ops->stop_link)
+	if (pcie->ops && pcie->ops->stop_link)
 		pcie->ops->stop_link(pcie);
 }
 
 static inline bool cdns_pcie_link_up(struct cdns_pcie *pcie)
 {
-	if (pcie->ops->link_up)
+	if (pcie->ops && pcie->ops->link_up)
 		return pcie->ops->link_up(pcie);
 
 	return true;

drivers/pci/controller/cadence/pcie-sg2042.c

@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * pcie-sg2042 - PCIe controller driver for Sophgo SG2042 SoC
+ *
+ * Copyright (C) 2025 Sophgo Technology Inc.
+ * Copyright (C) 2025 Chen Wang <unicorn_wang@outlook.com>
+ */
+
+#include <linux/mod_devicetable.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+#include "pcie-cadence.h"
+
+/*
+ * SG2042 only supports 4-byte aligned access, so for the rootbus (i.e. to
+ * read/write the Root Port itself, read32/write32 is required. For
+ * non-rootbus (i.e. to read/write the PCIe peripheral registers, supports
+ * 1/2/4 byte aligned access, so directly using read/write should be fine.
+ */
+
+static struct pci_ops sg2042_pcie_root_ops = {
+	.map_bus	= cdns_pci_map_bus,
+	.read		= pci_generic_config_read32,
+	.write		= pci_generic_config_write32,
+};
+
+static struct pci_ops sg2042_pcie_child_ops = {
+	.map_bus	= cdns_pci_map_bus,
+	.read		= pci_generic_config_read,
+	.write		= pci_generic_config_write,
+};
+
+static int sg2042_pcie_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct pci_host_bridge *bridge;
+	struct cdns_pcie *pcie;
+	struct cdns_pcie_rc *rc;
+	int ret;
+
+	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));
+	if (!bridge)
+		return dev_err_probe(dev, -ENOMEM, "Failed to alloc host bridge!\n");
+
+	bridge->ops = &sg2042_pcie_root_ops;
+	bridge->child_ops = &sg2042_pcie_child_ops;
+
+	rc = pci_host_bridge_priv(bridge);
+	pcie = &rc->pcie;
+	pcie->dev = dev;
+
+	platform_set_drvdata(pdev, pcie);
+
+	pm_runtime_set_active(dev);
+	pm_runtime_no_callbacks(dev);
+	devm_pm_runtime_enable(dev);
+
+	ret = cdns_pcie_init_phy(dev, pcie);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to init phy!\n");
+
+	ret = cdns_pcie_host_setup(rc);
+	if (ret) {
+		dev_err_probe(dev, ret, "Failed to setup host!\n");
+		cdns_pcie_disable_phy(pcie);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void sg2042_pcie_remove(struct platform_device *pdev)
+{
+	struct cdns_pcie *pcie = platform_get_drvdata(pdev);
+	struct device *dev = &pdev->dev;
+	struct cdns_pcie_rc *rc;
+
+	rc = container_of(pcie, struct cdns_pcie_rc, pcie);
+	cdns_pcie_host_disable(rc);
+
+	cdns_pcie_disable_phy(pcie);
+
+	pm_runtime_disable(dev);
+}
+
+static int sg2042_pcie_suspend_noirq(struct device *dev)
+{
+	struct cdns_pcie *pcie = dev_get_drvdata(dev);
+
+	cdns_pcie_disable_phy(pcie);
+
+	return 0;
+}
+
+static int sg2042_pcie_resume_noirq(struct device *dev)
+{
+	struct cdns_pcie *pcie = dev_get_drvdata(dev);
+	int ret;
+
+	ret = cdns_pcie_enable_phy(pcie);
+	if (ret) {
+		dev_err(dev, "failed to enable PHY\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static DEFINE_NOIRQ_DEV_PM_OPS(sg2042_pcie_pm_ops,
+			       sg2042_pcie_suspend_noirq,
+			       sg2042_pcie_resume_noirq);
+
+static const struct of_device_id sg2042_pcie_of_match[] = {
+	{ .compatible = "sophgo,sg2042-pcie-host" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, sg2042_pcie_of_match);
+
+static struct platform_driver sg2042_pcie_driver = {
+	.driver = {
+		.name		= "sg2042-pcie",
+		.of_match_table	= sg2042_pcie_of_match,
+		.pm		= pm_sleep_ptr(&sg2042_pcie_pm_ops),
+	},
+	.probe		= sg2042_pcie_probe,
+	.remove		= sg2042_pcie_remove,
+};
+module_platform_driver(sg2042_pcie_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("PCIe controller driver for SG2042 SoCs");
+MODULE_AUTHOR("Chen Wang <unicorn_wang@outlook.com>");