On 8/28/2025 7:47 AM, Chen Wang wrote:
From: Chen Wang <unicorn_wang@xxxxxxxxxxx>
Add support for PCIe controller in SG2042 SoC. The controller
uses the Cadence PCIe core programmed by pcie-cadence*.c. The
PCIe controller will work in host mode only.
Signed-off-by: Chen Wang <unicorn_wang@xxxxxxxxxxx>
---
drivers/pci/controller/cadence/Kconfig | 12 ++
drivers/pci/controller/cadence/Makefile | 1 +
drivers/pci/controller/cadence/pcie-sg2042.c | 134 +++++++++++++++++++
3 files changed, 147 insertions(+)
create mode 100644 drivers/pci/controller/cadence/pcie-sg2042.c
diff --git a/drivers/pci/controller/cadence/Kconfig b/drivers/pci/controller/cadence/Kconfig
index 666e16b6367f..b1f1941d5208 100644
--- a/drivers/pci/controller/cadence/Kconfig
+++ b/drivers/pci/controller/cadence/Kconfig
@@ -42,6 +42,17 @@ config PCIE_CADENCE_PLAT_EP
endpoint mode. This PCIe controller may be embedded into many
different vendors SoCs.
+config PCIE_SG2042
+ bool "Sophgo SG2042 PCIe controller (host mode)"
+ depends on ARCH_SOPHGO || COMPILE_TEST
+ depends on OF
+ depends on PCI_MSI
+ 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 +78,5 @@ 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
diff --git a/drivers/pci/controller/cadence/Makefile b/drivers/pci/controller/cadence/Makefile
index 9bac5fb2f13d..4df4456d9539 100644
--- a/drivers/pci/controller/cadence/Makefile
+++ b/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) += pcie-sg2042.o
diff --git a/drivers/pci/controller/cadence/pcie-sg2042.c b/drivers/pci/controller/cadence/pcie-sg2042.c
new file mode 100644
index 000000000000..fe434dc2967e
--- /dev/null
+++ b/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@xxxxxxxxxxx>
+ */
+
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+#include "pcie-cadence.h"
+
+/*
+ * SG2042 only support 4-byte aligned access, so for the rootbus (i.e. to read
support -> supports
+ * the Root Port itself, read32 is required. For non-rootbus (i.e. to read
+ * the PCIe peripheral registers, supports 1/2/4 byte aligned access, so
+ * directly using read should be fine.
+ *
+ * The same is true for write.
[clip]
+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;
+
+ pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
+ if (!pcie)
+ return -ENOMEM;
+
+ bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));
+ if (!bridge) {
+ dev_err(dev, "Failed to alloc host bridge!\n");
+ return -ENOMEM;
+ }
+
+ bridge->ops = &sg2042_pcie_host_ops;
+
+ rc = pci_host_bridge_priv(bridge);
+ pcie = &rc->pcie;
First, pcie is allocated and then reassigned to &rc->pcie,
which makes the initial allocation effectively leaked and unnecessary.
+ pcie->dev = dev;
+
+ platform_set_drvdata(pdev, pcie);
+
+ pm_runtime_enable(dev);
+
+ ret = pm_runtime_get_sync(dev);
+ if (ret < 0) {
+ dev_err(dev, "pm_runtime_get_sync failed\n");
+ goto err_get_sync;
+ }
+
+ ret = cdns_pcie_init_phy(dev, pcie);
+ if (ret) {
+ dev_err(dev, "Failed to init phy!\n");
+ goto err_get_sync;
+ }
+
+ ret = cdns_pcie_host_setup(rc);
+ if (ret < 0) {
+ dev_err(dev, "Failed to setup host!\n");
+ goto err_host_setup;
+ }
+
+ return 0;
+
+err_host_setup:
+ cdns_pcie_disable_phy(pcie);
+
+err_get_sync:
+ pm_runtime_put(dev);
+ pm_runtime_disable(dev);
+
+ return ret;
+}
Thanks,
Alok
