[PATCH net-next 3/3] net: stmmac: Add UltraRISC DP1000 GMAC support

[Jia Wang]

The DP1000 GMAC integration provides fixed TX and RX RGMII clock delays
that cannot be disabled. For boards without PCB delays, "rgmii-id"
describes the link, but passing that mode unchanged to the PHY would enable
a second set of delays.

Use phy_fix_phy_mode_for_mac_delays() to translate "rgmii-id" to "rgmii"
before attaching the PHY. Reject other RGMII modes because the fixed MAC
delays cannot be combined with them without duplicating or omitting a
delay.

Signed-off-by: Jia Wang <wangjia at ultrarisc.com>
---
 MAINTAINERS                                        |  1 +
 drivers/net/ethernet/stmicro/stmmac/Kconfig        | 11 +++++
 drivers/net/ethernet/stmicro/stmmac/Makefile       |  1 +
 .../net/ethernet/stmicro/stmmac/dwmac-ultrarisc.c  | 54 ++++++++++++++++++++++
 4 files changed, 67 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 3b96ff0734e6..aacbab369b51 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -28008,6 +28008,7 @@ ULTRARISC DP1000 DWMAC GLUE LAYER
 M:	Jia Wang <wangjia at ultrarisc.com>
 S:	Maintained
 F:	Documentation/devicetree/bindings/net/ultrarisc,dp1000-gmac.yaml
+F:	drivers/net/ethernet/stmicro/stmmac/dwmac-ultrarisc.c
 
 ULTRARISC DP1000 PINCTRL DRIVER
 M:	Jia Wang <wangjia at ultrarisc.com>
diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
index e3dd5adda5ac..ab3c4cf96423 100644
--- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
+++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
@@ -319,6 +319,17 @@ config DWMAC_THEAD
 	  the stmmac device driver. This driver is used for T-HEAD TH1520
 	  ethernet controller.
 
+config DWMAC_ULTRARISC
+	tristate "UltraRISC DWMAC support"
+	default ARCH_ULTRARISC
+	depends on OF && (ARCH_ULTRARISC || COMPILE_TEST)
+	help
+	  Support for the Ethernet controller on the UltraRISC DP1000 SoC.
+
+	  This selects the UltraRISC platform specific glue layer support
+	  for the stmmac device driver. This driver is used for the DP1000
+	  GMAC Ethernet controller.
+
 config DWMAC_IMX8
 	tristate "NXP IMX8 DWMAC support"
 	default ARCH_MXC
diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
index a1cea2f57252..b16a456b730e 100644
--- a/drivers/net/ethernet/stmicro/stmmac/Makefile
+++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_DWMAC_SUNXI)	+= dwmac-sunxi.o
 obj-$(CONFIG_DWMAC_SUN8I)	+= dwmac-sun8i.o
 obj-$(CONFIG_DWMAC_SUN55I)	+= dwmac-sun55i.o
 obj-$(CONFIG_DWMAC_THEAD)	+= dwmac-thead.o
+obj-$(CONFIG_DWMAC_ULTRARISC)	+= dwmac-ultrarisc.o
 obj-$(CONFIG_DWMAC_DWC_QOS_ETH)	+= dwmac-dwc-qos-eth.o
 obj-$(CONFIG_DWMAC_INTEL_PLAT)	+= dwmac-intel-plat.o
 obj-$(CONFIG_DWMAC_LOONGSON1)	+= dwmac-loongson1.o
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-ultrarisc.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-ultrarisc.c
new file mode 100644
index 000000000000..4bdda2665338
--- /dev/null
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-ultrarisc.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * UltraRISC DWMAC platform driver
+ *
+ * Copyright (C) 2026 UltraRISC Technology (Shanghai) Co., Ltd.
+ */
+
+#include <linux/module.h>
+#include <linux/phy.h>
+#include <linux/platform_device.h>
+
+#include "stmmac_platform.h"
+
+static int ultrarisc_dwmac_probe(struct platform_device *pdev)
+{
+	struct plat_stmmacenet_data *plat_dat;
+	struct stmmac_resources stmmac_res;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	ret = stmmac_get_platform_resources(pdev, &stmmac_res);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to get resources\n");
+
+	plat_dat = devm_stmmac_probe_config_dt(pdev, stmmac_res.mac);
+	if (IS_ERR(plat_dat))
+		return dev_err_probe(dev, PTR_ERR(plat_dat), "failed to parse DT parameters\n");
+
+	plat_dat->phy_interface =
+		phy_fix_phy_mode_for_mac_delays(plat_dat->phy_interface, true, true);
+	if (plat_dat->phy_interface == PHY_INTERFACE_MODE_NA)
+		return dev_err_probe(dev, -EINVAL, "unsupported phy interface mode\n");
+
+	return devm_stmmac_pltfr_probe(pdev, plat_dat, &stmmac_res);
+}
+
+static const struct of_device_id ultrarisc_dwmac_match[] = {
+	{ .compatible = "ultrarisc,dp1000-gmac" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ultrarisc_dwmac_match);
+
+static struct platform_driver ultrarisc_dwmac_driver = {
+	.probe = ultrarisc_dwmac_probe,
+	.driver = {
+		.name = "ultrarisc-dwmac",
+		.pm = &stmmac_pltfr_pm_ops,
+		.of_match_table = ultrarisc_dwmac_match,
+	},
+};
+module_platform_driver(ultrarisc_dwmac_driver);
+
+MODULE_DESCRIPTION("UltraRISC DWMAC platform driver");
+MODULE_LICENSE("GPL");

-- 
2.34.1