net: stmmac: Add glue layer for Loongson-1 SoC

This glue driver is created based on the arch-code
implemented earlier with the platform-specific settings.

Use syscon for SYSCON register access.

And modify MAINTAINERS to add a new F: entry for this driver.

Partially based on the previous work by Serge Semin.

Signed-off-by: Keguang Zhang <keguang.zhang@gmail.com>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -14348,6 +14348,7 @@ F:	Documentation/devicetree/bindings/*/loongson,ls1*.yaml
 F:	arch/mips/include/asm/mach-loongson32/
 F:	arch/mips/loongson32/
 F:	drivers/*/*loongson1*
+F:	drivers/net/ethernet/stmicro/stmmac/dwmac-loongson1.c
 
 MIPS/LOONGSON2EF ARCHITECTURE
 M:	Jiaxun Yang <jiaxun.yang@flygoat.com>

drivers/net/ethernet/stmicro/stmmac/Kconfig

@@ -239,6 +239,17 @@ config DWMAC_INTEL_PLAT
 	  the stmmac device driver. This driver is used for the Intel Keem Bay
 	  SoC.
 
+config DWMAC_LOONGSON1
+	tristate "Loongson1 GMAC support"
+	default MACH_LOONGSON32
+	depends on OF && (MACH_LOONGSON32 || COMPILE_TEST)
+	help
+	  Support for ethernet controller on Loongson1 SoC.
+
+	  This selects Loongson1 SoC glue layer support for the stmmac
+	  device driver. This driver is used for Loongson1-based boards
+	  like Loongson LS1B/LS1C.
+
 config DWMAC_TEGRA
 	tristate "NVIDIA Tegra MGBE support"
 	depends on ARCH_TEGRA || COMPILE_TEST

drivers/net/ethernet/stmicro/stmmac/Makefile

@@ -29,6 +29,7 @@ obj-$(CONFIG_DWMAC_SUNXI)	+= dwmac-sunxi.o
 obj-$(CONFIG_DWMAC_SUN8I)	+= dwmac-sun8i.o
 obj-$(CONFIG_DWMAC_DWC_QOS_ETH)	+= dwmac-dwc-qos-eth.o
 obj-$(CONFIG_DWMAC_INTEL_PLAT)	+= dwmac-intel-plat.o
+obj-$(CONFIG_DWMAC_LOONGSON1)	+= dwmac-loongson1.o
 obj-$(CONFIG_DWMAC_GENERIC)	+= dwmac-generic.o
 obj-$(CONFIG_DWMAC_IMX8)	+= dwmac-imx.o
 obj-$(CONFIG_DWMAC_TEGRA)	+= dwmac-tegra.o

drivers/net/ethernet/stmicro/stmmac/dwmac-loongson1.c

@@ -0,0 +1,209 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Loongson-1 DWMAC glue layer
+ *
+ * Copyright (C) 2011-2023 Keguang Zhang <keguang.zhang@gmail.com>
+ */
+
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include "stmmac.h"
+#include "stmmac_platform.h"
+
+#define LS1B_GMAC0_BASE		(0x1fe10000)
+#define LS1B_GMAC1_BASE		(0x1fe20000)
+
+/* Loongson-1 SYSCON Registers */
+#define LS1X_SYSCON0		(0x0)
+#define LS1X_SYSCON1		(0x4)
+
+/* Loongson-1B SYSCON Register Bits */
+#define GMAC1_USE_UART1		BIT(4)
+#define GMAC1_USE_UART0		BIT(3)
+
+#define GMAC1_SHUT		BIT(13)
+#define GMAC0_SHUT		BIT(12)
+
+#define GMAC1_USE_TXCLK		BIT(3)
+#define GMAC0_USE_TXCLK		BIT(2)
+#define GMAC1_USE_PWM23		BIT(1)
+#define GMAC0_USE_PWM01		BIT(0)
+
+/* Loongson-1C SYSCON Register Bits */
+#define GMAC_SHUT		BIT(6)
+
+#define PHY_INTF_SELI		GENMASK(30, 28)
+#define PHY_INTF_MII		FIELD_PREP(PHY_INTF_SELI, 0)
+#define PHY_INTF_RMII		FIELD_PREP(PHY_INTF_SELI, 4)
+
+struct ls1x_dwmac {
+	struct plat_stmmacenet_data *plat_dat;
+	struct regmap *regmap;
+};
+
+static int ls1b_dwmac_syscon_init(struct platform_device *pdev, void *priv)
+{
+	struct ls1x_dwmac *dwmac = priv;
+	struct plat_stmmacenet_data *plat = dwmac->plat_dat;
+	struct regmap *regmap = dwmac->regmap;
+	struct resource *res;
+	unsigned long reg_base;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "Could not get IO_MEM resources\n");
+		return -EINVAL;
+	}
+	reg_base = (unsigned long)res->start;
+
+	if (reg_base == LS1B_GMAC0_BASE) {
+		switch (plat->phy_interface) {
+		case PHY_INTERFACE_MODE_RGMII_ID:
+			regmap_update_bits(regmap, LS1X_SYSCON0,
+					   GMAC0_USE_TXCLK | GMAC0_USE_PWM01,
+					   0);
+			break;
+		case PHY_INTERFACE_MODE_MII:
+			regmap_update_bits(regmap, LS1X_SYSCON0,
+					   GMAC0_USE_TXCLK | GMAC0_USE_PWM01,
+					   GMAC0_USE_TXCLK | GMAC0_USE_PWM01);
+			break;
+		default:
+			dev_err(&pdev->dev, "Unsupported PHY mode %u\n",
+				plat->phy_interface);
+			return -EOPNOTSUPP;
+		}
+
+		regmap_update_bits(regmap, LS1X_SYSCON0, GMAC0_SHUT, 0);
+	} else if (reg_base == LS1B_GMAC1_BASE) {
+		regmap_update_bits(regmap, LS1X_SYSCON0,
+				   GMAC1_USE_UART1 | GMAC1_USE_UART0,
+				   GMAC1_USE_UART1 | GMAC1_USE_UART0);
+
+		switch (plat->phy_interface) {
+		case PHY_INTERFACE_MODE_RGMII_ID:
+			regmap_update_bits(regmap, LS1X_SYSCON1,
+					   GMAC1_USE_TXCLK | GMAC1_USE_PWM23,
+					   0);
+
+			break;
+		case PHY_INTERFACE_MODE_MII:
+			regmap_update_bits(regmap, LS1X_SYSCON1,
+					   GMAC1_USE_TXCLK | GMAC1_USE_PWM23,
+					   GMAC1_USE_TXCLK | GMAC1_USE_PWM23);
+			break;
+		default:
+			dev_err(&pdev->dev, "Unsupported PHY mode %u\n",
+				plat->phy_interface);
+			return -EOPNOTSUPP;
+		}
+
+		regmap_update_bits(regmap, LS1X_SYSCON1, GMAC1_SHUT, 0);
+	} else {
+		dev_err(&pdev->dev, "Invalid Ethernet MAC base address %lx",
+			reg_base);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int ls1c_dwmac_syscon_init(struct platform_device *pdev, void *priv)
+{
+	struct ls1x_dwmac *dwmac = priv;
+	struct plat_stmmacenet_data *plat = dwmac->plat_dat;
+	struct regmap *regmap = dwmac->regmap;
+
+	switch (plat->phy_interface) {
+	case PHY_INTERFACE_MODE_MII:
+		regmap_update_bits(regmap, LS1X_SYSCON1, PHY_INTF_SELI,
+				   PHY_INTF_MII);
+		break;
+	case PHY_INTERFACE_MODE_RMII:
+		regmap_update_bits(regmap, LS1X_SYSCON1, PHY_INTF_SELI,
+				   PHY_INTF_RMII);
+		break;
+	default:
+		dev_err(&pdev->dev, "Unsupported PHY-mode %u\n",
+			plat->phy_interface);
+		return -EOPNOTSUPP;
+	}
+
+	regmap_update_bits(regmap, LS1X_SYSCON0, GMAC0_SHUT, 0);
+
+	return 0;
+}
+
+static int ls1x_dwmac_probe(struct platform_device *pdev)
+{
+	struct plat_stmmacenet_data *plat_dat;
+	struct stmmac_resources stmmac_res;
+	struct regmap *regmap;
+	struct ls1x_dwmac *dwmac;
+	int (*init)(struct platform_device *pdev, void *priv);
+	int ret;
+
+	ret = stmmac_get_platform_resources(pdev, &stmmac_res);
+	if (ret)
+		return ret;
+
+	/* Probe syscon */
+	regmap = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
+						 "loongson,ls1-syscon");
+	if (IS_ERR(regmap))
+		return dev_err_probe(&pdev->dev, PTR_ERR(regmap),
+				     "Unable to find syscon\n");
+
+	init = of_device_get_match_data(&pdev->dev);
+	if (!init) {
+		dev_err(&pdev->dev, "No of match data provided\n");
+		return -EINVAL;
+	}
+
+	dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
+	if (!dwmac)
+		return -ENOMEM;
+
+	plat_dat = devm_stmmac_probe_config_dt(pdev, stmmac_res.mac);
+	if (IS_ERR(plat_dat))
+		return dev_err_probe(&pdev->dev, PTR_ERR(plat_dat),
+				     "dt configuration failed\n");
+
+	plat_dat->bsp_priv = dwmac;
+	plat_dat->init = init;
+	dwmac->plat_dat = plat_dat;
+	dwmac->regmap = regmap;
+
+	return devm_stmmac_pltfr_probe(pdev, plat_dat, &stmmac_res);
+}
+
+static const struct of_device_id ls1x_dwmac_match[] = {
+	{
+		.compatible = "loongson,ls1b-gmac",
+		.data = &ls1b_dwmac_syscon_init,
+	},
+	{
+		.compatible = "loongson,ls1c-emac",
+		.data = &ls1c_dwmac_syscon_init,
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ls1x_dwmac_match);
+
+static struct platform_driver ls1x_dwmac_driver = {
+	.probe = ls1x_dwmac_probe,
+	.driver = {
+		.name = "loongson1-dwmac",
+		.of_match_table = ls1x_dwmac_match,
+	},
+};
+module_platform_driver(ls1x_dwmac_driver);
+
+MODULE_AUTHOR("Keguang Zhang <keguang.zhang@gmail.com>");
+MODULE_DESCRIPTION("Loongson-1 DWMAC glue layer");
+MODULE_LICENSE("GPL");