net: stmmac: Add dwmac-intel-plat for GBE driver

Add dwmac-intel-plat to enable the stmmac driver in Intel Keem Bay.
Also add fix_mac_speed and tx_clk in order to change link speeds.
This is required as mac_speed_o is not connected in the
Intel Keem Bay SoC.

Signed-off-by: Rusaimi Amira Ruslan <rusaimi.amira.rusaimi@intel.com>
Signed-off-by: Vineetha G. Jaya Kumaran <vineetha.g.jaya.kumaran@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/Kconfig

@@ -209,6 +209,16 @@ config DWMAC_IMX8
 	  device driver. This driver is used for i.MX8 series like
 	  iMX8MP/iMX8DXL GMAC ethernet controller.
 
+config DWMAC_INTEL_PLAT
+	tristate "Intel dwmac support"
+	depends on OF && COMMON_CLK
+	depends on STMMAC_ETH
+	help
+	  Support for ethernet controllers on Intel SoCs
+
+	  This selects the Intel platform specific glue layer support for
+	  the stmmac device driver. This driver is used for the Intel Keem Bay
+	  SoC.
 endif
 
 config DWMAC_INTEL

drivers/net/ethernet/stmicro/stmmac/Makefile

@@ -26,6 +26,7 @@ obj-$(CONFIG_DWMAC_STM32)	+= dwmac-stm32.o
 obj-$(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_GENERIC)	+= dwmac-generic.o
 obj-$(CONFIG_DWMAC_IMX8)	+= dwmac-imx.o
 stmmac-platform-objs:= stmmac_platform.o

drivers/net/ethernet/stmicro/stmmac/dwmac-intel-plat.c

@@ -0,0 +1,191 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Intel DWMAC platform driver
+ *
+ * Copyright(C) 2020 Intel Corporation
+ */
+
+#include <linux/ethtool.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/stmmac.h>
+
+#include "stmmac.h"
+#include "stmmac_platform.h"
+
+struct intel_dwmac {
+	struct device *dev;
+	struct clk *tx_clk;
+	const struct intel_dwmac_data *data;
+};
+
+struct intel_dwmac_data {
+	void (*fix_mac_speed)(void *priv, unsigned int speed);
+	unsigned long ptp_ref_clk_rate;
+	unsigned long tx_clk_rate;
+	bool tx_clk_en;
+};
+
+static void kmb_eth_fix_mac_speed(void *priv, unsigned int speed)
+{
+	struct intel_dwmac *dwmac = priv;
+	unsigned long rate;
+	int ret;
+
+	rate = clk_get_rate(dwmac->tx_clk);
+
+	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\n");
+		break;
+	}
+
+	ret = clk_set_rate(dwmac->tx_clk, rate);
+	if (ret)
+		dev_err(dwmac->dev, "Failed to configure tx clock rate\n");
+}
+
+static const struct intel_dwmac_data kmb_data = {
+	.fix_mac_speed = kmb_eth_fix_mac_speed,
+	.ptp_ref_clk_rate = 200000000,
+	.tx_clk_rate = 125000000,
+	.tx_clk_en = true,
+};
+
+static const struct of_device_id intel_eth_plat_match[] = {
+	{ .compatible = "intel,keembay-dwmac", .data = &kmb_data },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, intel_eth_plat_match);
+
+static int intel_eth_plat_probe(struct platform_device *pdev)
+{
+	struct net_device *ndev = platform_get_drvdata(pdev);
+	struct stmmac_priv *priv = netdev_priv(ndev);
+	struct plat_stmmacenet_data *plat_dat;
+	struct stmmac_resources stmmac_res;
+	const struct of_device_id *match;
+	struct intel_dwmac *dwmac;
+	unsigned long rate;
+	int ret;
+
+	plat_dat = priv->plat;
+	ret = stmmac_get_platform_resources(pdev, &stmmac_res);
+	if (ret)
+		return ret;
+
+	plat_dat = stmmac_probe_config_dt(pdev, &stmmac_res.mac);
+	if (IS_ERR(plat_dat)) {
+		dev_err(&pdev->dev, "dt configuration failed\n");
+		return PTR_ERR(plat_dat);
+	}
+
+	dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
+	if (!dwmac) {
+		ret = -ENOMEM;
+		goto err_remove_config_dt;
+	}
+
+	dwmac->dev = &pdev->dev;
+	dwmac->tx_clk = NULL;
+
+	match = of_match_device(intel_eth_plat_match, &pdev->dev);
+	if (match && match->data) {
+		dwmac->data = (const struct intel_dwmac_data *)match->data;
+
+		if (dwmac->data->fix_mac_speed)
+			plat_dat->fix_mac_speed = dwmac->data->fix_mac_speed;
+
+		/* Enable TX clock */
+		if (dwmac->data->tx_clk_en) {
+			dwmac->tx_clk = devm_clk_get(&pdev->dev, "tx_clk");
+			if (IS_ERR(dwmac->tx_clk))
+				goto err_remove_config_dt;
+
+			clk_prepare_enable(dwmac->tx_clk);
+
+			/* Check and configure TX clock rate */
+			rate = clk_get_rate(dwmac->tx_clk);
+			if (dwmac->data->tx_clk_rate &&
+			    rate != dwmac->data->tx_clk_rate) {
+				rate = dwmac->data->tx_clk_rate;
+				ret = clk_set_rate(dwmac->tx_clk, rate);
+				if (ret) {
+					dev_err(&pdev->dev,
+						"Failed to set tx_clk\n");
+					return ret;
+				}
+			}
+		}
+
+		/* Check and configure PTP ref clock rate */
+		rate = clk_get_rate(plat_dat->clk_ptp_ref);
+		if (dwmac->data->ptp_ref_clk_rate &&
+		    rate != dwmac->data->ptp_ref_clk_rate) {
+			rate = dwmac->data->ptp_ref_clk_rate;
+			ret = clk_set_rate(plat_dat->clk_ptp_ref, rate);
+			if (ret) {
+				dev_err(&pdev->dev,
+					"Failed to set clk_ptp_ref\n");
+				return ret;
+			}
+		}
+	}
+
+	plat_dat->bsp_priv = dwmac;
+
+	ret = stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res);
+	if (ret) {
+		if (dwmac->tx_clk)
+			clk_disable_unprepare(dwmac->tx_clk);
+
+		goto err_remove_config_dt;
+	}
+
+	return 0;
+
+err_remove_config_dt:
+	stmmac_remove_config_dt(pdev, plat_dat);
+
+	return ret;
+}
+
+static int intel_eth_plat_remove(struct platform_device *pdev)
+{
+	struct intel_dwmac *dwmac = get_stmmac_bsp_priv(&pdev->dev);
+	int ret;
+
+	ret = stmmac_pltfr_remove(pdev);
+
+	if (dwmac->tx_clk)
+		clk_disable_unprepare(dwmac->tx_clk);
+
+	return ret;
+}
+
+static struct platform_driver intel_eth_plat_driver = {
+	.probe  = intel_eth_plat_probe,
+	.remove = intel_eth_plat_remove,
+	.driver = {
+		.name		= "intel-eth-plat",
+		.pm		= &stmmac_pltfr_pm_ops,
+		.of_match_table = intel_eth_plat_match,
+	},
+};
+module_platform_driver(intel_eth_plat_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Intel DWMAC platform driver");