net: stmmac: Add glue layer for StarFive JH7110 SoC

This adds StarFive dwmac driver support on the StarFive JH7110 SoC.
Tested-by: Tommaso Merciai <tomm.merciai@gmail.com>
Co-developed-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Samin Guo <samin.guo@starfivetech.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

MAINTAINERS

@@ -19933,6 +19933,7 @@ M:	Emil Renner Berthing <kernel@esmil.dk>
 M:	Samin Guo <samin.guo@starfivetech.com>
 S:	Maintained
 F:	Documentation/devicetree/bindings/net/starfive,jh7110-dwmac.yaml
+F:	drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c
 
 STARFIVE JH7100 CLOCK DRIVERS
 M:	Emil Renner Berthing <kernel@esmil.dk>

drivers/net/ethernet/stmicro/stmmac/Kconfig

@@ -165,6 +165,18 @@ config DWMAC_SOCFPGA
 	  for the stmmac device driver. This driver is used for
 	  arria5 and cyclone5 FPGA SoCs.
 
+config DWMAC_STARFIVE
+	tristate "StarFive dwmac support"
+	depends on OF && (ARCH_STARFIVE || COMPILE_TEST)
+	select MFD_SYSCON
+	default m if ARCH_STARFIVE
+	help
+	  Support for ethernet controllers on StarFive RISC-V SoCs
+
+	  This selects the StarFive platform specific glue layer support for
+	  the stmmac device driver. This driver is used for StarFive JH7110
+	  ethernet controller.
+
 config DWMAC_STI
 	tristate "STi GMAC support"
 	default ARCH_STI

drivers/net/ethernet/stmicro/stmmac/Makefile

@@ -23,6 +23,7 @@ obj-$(CONFIG_DWMAC_OXNAS)	+= dwmac-oxnas.o
 obj-$(CONFIG_DWMAC_QCOM_ETHQOS)	+= dwmac-qcom-ethqos.o
 obj-$(CONFIG_DWMAC_ROCKCHIP)	+= dwmac-rk.o
 obj-$(CONFIG_DWMAC_SOCFPGA)	+= dwmac-altr-socfpga.o
+obj-$(CONFIG_DWMAC_STARFIVE)	+= dwmac-starfive.o
 obj-$(CONFIG_DWMAC_STI)		+= dwmac-sti.o
 obj-$(CONFIG_DWMAC_STM32)	+= dwmac-stm32.o
 obj-$(CONFIG_DWMAC_SUNXI)	+= dwmac-sunxi.o

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

+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * StarFive DWMAC platform driver
+ *
+ * Copyright (C) 2021 Emil Renner Berthing <kernel@esmil.dk>
+ * Copyright (C) 2022 StarFive Technology Co., Ltd.
+ *
+ */
+
+#include <linux/mfd/syscon.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+
+#include "stmmac_platform.h"
+
+struct starfive_dwmac {
+	struct device *dev;
+	struct clk *clk_tx;
+};
+
+static void starfive_dwmac_fix_mac_speed(void *priv, unsigned int speed)
+{
+	struct starfive_dwmac *dwmac = priv;
+	unsigned long rate;
+	int err;
+
+	rate = clk_get_rate(dwmac->clk_tx);
+
+	switch (speed) {
+	case SPEED_1000:
+		rate = 125000000;
+		break;
+	case SPEED_100:
+		rate = 25000000;
+		break;
+	case SPEED_10:
+		rate = 2500000;
+		break;
+	default:
+		dev_err(dwmac->dev, "invalid speed %u\n", speed);
+		break;
+	}
+
+	err = clk_set_rate(dwmac->clk_tx, rate);
+	if (err)
+		dev_err(dwmac->dev, "failed to set tx rate %lu\n", rate);
+}
+
+static int starfive_dwmac_probe(struct platform_device *pdev)
+{
+	struct plat_stmmacenet_data *plat_dat;
+	struct stmmac_resources stmmac_res;
+	struct starfive_dwmac *dwmac;
+	struct clk *clk_gtx;
+	int err;
+
+	err = stmmac_get_platform_resources(pdev, &stmmac_res);
+	if (err)
+		return dev_err_probe(&pdev->dev, err,
+				     "failed to get resources\n");
+
+	plat_dat = 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");
+
+	dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
+	if (!dwmac)
+		return -ENOMEM;
+
+	dwmac->clk_tx = devm_clk_get_enabled(&pdev->dev, "tx");
+	if (IS_ERR(dwmac->clk_tx))
+		return dev_err_probe(&pdev->dev, PTR_ERR(dwmac->clk_tx),
+				     "error getting tx clock\n");
+
+	clk_gtx = devm_clk_get_enabled(&pdev->dev, "gtx");
+	if (IS_ERR(clk_gtx))
+		return dev_err_probe(&pdev->dev, PTR_ERR(clk_gtx),
+				     "error getting gtx clock\n");
+
+	/* Generally, the rgmii_tx clock is provided by the internal clock,
+	 * which needs to match the corresponding clock frequency according
+	 * to different speeds. If the rgmii_tx clock is provided by the
+	 * external rgmii_rxin, there is no need to configure the clock
+	 * internally, because rgmii_rxin will be adaptively adjusted.
+	 */
+	if (!device_property_read_bool(&pdev->dev, "starfive,tx-use-rgmii-clk"))
+		plat_dat->fix_mac_speed = starfive_dwmac_fix_mac_speed;
+
+	dwmac->dev = &pdev->dev;
+	plat_dat->bsp_priv = dwmac;
+	plat_dat->dma_cfg->dche = true;
+
+	err = stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res);
+	if (err) {
+		stmmac_remove_config_dt(pdev, plat_dat);
+		return err;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id starfive_dwmac_match[] = {
+	{ .compatible = "starfive,jh7110-dwmac"	},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, starfive_dwmac_match);
+
+static struct platform_driver starfive_dwmac_driver = {
+	.probe  = starfive_dwmac_probe,
+	.remove = stmmac_pltfr_remove,
+	.driver = {
+		.name = "starfive-dwmac",
+		.pm = &stmmac_pltfr_pm_ops,
+		.of_match_table = starfive_dwmac_match,
+	},
+};
+module_platform_driver(starfive_dwmac_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("StarFive DWMAC platform driver");
+MODULE_AUTHOR("Emil Renner Berthing <kernel@esmil.dk>");
+MODULE_AUTHOR("Samin Guo <samin.guo@starfivetech.com>");