net: ethernet: dwmac: add ethernet glue logic for NXP imx8 chip

NXP imx8 family like imx8mp/imx8dxl chips support Synopsys MAC 5.10a IP.
This patch adds settings for NXP imx8 glue layer:
- clocks
- dwmac address width
- phy interface mode selection
- adjust rgmii txclk rate

v2:
- adjust code sequences in order to have reverse christmas
tree local variable ordering.

Signed-off-by: Fugang Duan <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/stmicro/stmmac/Kconfig

···
 	  This selects Allwinner SoC glue layer support for the
 	  stmmac device driver. This driver is used for H3/A83T/A64
 	  EMAC ethernet controller.
+
+config DWMAC_IMX8
+	tristate "NXP IMX8 DWMAC support"
+	default ARCH_MXC
+	depends on OF && (ARCH_MXC || COMPILE_TEST)
+	select MFD_SYSCON
+	---help---
+	  Support for ethernet controller on NXP i.MX8 SOCs.
+
+	  This selects NXP SoC glue layer support for the stmmac
+	  device driver. This driver is used for i.MX8 series like
+	  iMX8MP/iMX8DXL GMAC ethernet controller.
+
 endif
 
 config DWMAC_INTEL

drivers/net/ethernet/stmicro/stmmac/Makefile

···
 obj-$(CONFIG_DWMAC_SUN8I)	+= dwmac-sun8i.o
 obj-$(CONFIG_DWMAC_DWC_QOS_ETH)	+= dwmac-dwc-qos-eth.o
 obj-$(CONFIG_DWMAC_GENERIC)	+= dwmac-generic.o
+obj-$(CONFIG_DWMAC_IMX8)	+= dwmac-imx.o
 stmmac-platform-objs:= stmmac_platform.o
 dwmac-altr-socfpga-objs := altr_tse_pcs.o dwmac-socfpga.o
 

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

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * dwmac-imx.c - DWMAC Specific Glue layer for NXP imx8
+ *
+ * Copyright 2020 NXP
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/gpio/consumer.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_net.h>
+#include <linux/phy.h>
+#include <linux/platform_device.h>
+#include <linux/pm_wakeirq.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/stmmac.h>
+
+#include "stmmac_platform.h"
+
+#define GPR_ENET_QOS_INTF_MODE_MASK	GENMASK(21, 16)
+#define GPR_ENET_QOS_INTF_SEL_MII	(0x0 << 16)
+#define GPR_ENET_QOS_INTF_SEL_RMII	(0x4 << 16)
+#define GPR_ENET_QOS_INTF_SEL_RGMII	(0x1 << 16)
+#define GPR_ENET_QOS_CLK_GEN_EN		(0x1 << 19)
+#define GPR_ENET_QOS_CLK_TX_CLK_SEL	(0x1 << 20)
+#define GPR_ENET_QOS_RGMII_EN		(0x1 << 21)
+
+struct imx_dwmac_ops {
+	u32 addr_width;
+	bool mac_rgmii_txclk_auto_adj;
+
+	int (*set_intf_mode)(struct plat_stmmacenet_data *plat_dat);
+};
+
+struct imx_priv_data {
+	struct device *dev;
+	struct clk *clk_tx;
+	struct clk *clk_mem;
+	struct regmap *intf_regmap;
+	u32 intf_reg_off;
+	bool rmii_refclk_ext;
+
+	const struct imx_dwmac_ops *ops;
+	struct plat_stmmacenet_data *plat_dat;
+};
+
+static int imx8mp_set_intf_mode(struct plat_stmmacenet_data *plat_dat)
+{
+	struct imx_priv_data *dwmac = plat_dat->bsp_priv;
+	int val;
+
+	switch (plat_dat->interface) {
+	case PHY_INTERFACE_MODE_MII:
+		val = GPR_ENET_QOS_INTF_SEL_MII;
+		break;
+	case PHY_INTERFACE_MODE_RMII:
+		val = GPR_ENET_QOS_INTF_SEL_RMII;
+		val |= (dwmac->rmii_refclk_ext ? 0 : GPR_ENET_QOS_CLK_TX_CLK_SEL);
+		break;
+	case PHY_INTERFACE_MODE_RGMII:
+	case PHY_INTERFACE_MODE_RGMII_ID:
+	case PHY_INTERFACE_MODE_RGMII_RXID:
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+		val = GPR_ENET_QOS_INTF_SEL_RGMII |
+		      GPR_ENET_QOS_RGMII_EN;
+		break;
+	default:
+		pr_debug("imx dwmac doesn't support %d interface\n",
+			 plat_dat->interface);
+		return -EINVAL;
+	}
+
+	val |= GPR_ENET_QOS_CLK_GEN_EN;
+	return regmap_update_bits(dwmac->intf_regmap, dwmac->intf_reg_off,
+				  GPR_ENET_QOS_INTF_MODE_MASK, val);
+};
+
+static int
+imx8dxl_set_intf_mode(struct plat_stmmacenet_data *plat_dat)
+{
+	int ret = 0;
+
+	/* TBD: depends on imx8dxl scu interfaces to be upstreamed */
+	return ret;
+}
+
+static int imx_dwmac_init(struct platform_device *pdev, void *priv)
+{
+	struct plat_stmmacenet_data *plat_dat;
+	struct imx_priv_data *dwmac = priv;
+	int ret;
+
+	plat_dat = dwmac->plat_dat;
+
+	ret = clk_prepare_enable(dwmac->clk_mem);
+	if (ret) {
+		dev_err(&pdev->dev, "mem clock enable failed\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(dwmac->clk_tx);
+	if (ret) {
+		dev_err(&pdev->dev, "tx clock enable failed\n");
+		goto clk_tx_en_failed;
+	}
+
+	if (dwmac->ops->set_intf_mode) {
+		ret = dwmac->ops->set_intf_mode(plat_dat);
+		if (ret)
+			goto intf_mode_failed;
+	}
+
+	return 0;
+
+intf_mode_failed:
+	clk_disable_unprepare(dwmac->clk_tx);
+clk_tx_en_failed:
+	clk_disable_unprepare(dwmac->clk_mem);
+	return ret;
+}
+
+static void imx_dwmac_exit(struct platform_device *pdev, void *priv)
+{
+	struct imx_priv_data *dwmac = priv;
+
+	if (dwmac->clk_tx)
+		clk_disable_unprepare(dwmac->clk_tx);
+	clk_disable_unprepare(dwmac->clk_mem);
+}
+
+static void imx_dwmac_fix_speed(void *priv, unsigned int speed)
+{
+	struct plat_stmmacenet_data *plat_dat;
+	struct imx_priv_data *dwmac = priv;
+	unsigned long rate;
+	int err;
+
+	plat_dat = dwmac->plat_dat;
+
+	if (dwmac->ops->mac_rgmii_txclk_auto_adj ||
+	    (plat_dat->interface == PHY_INTERFACE_MODE_RMII) ||
+	    (plat_dat->interface == PHY_INTERFACE_MODE_MII))
+		return;
+
+	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);
+		return;
+	}
+
+	err = clk_set_rate(dwmac->clk_tx, rate);
+	if (err < 0)
+		dev_err(dwmac->dev, "failed to set tx rate %lu\n", rate);
+}
+
+static int
+imx_dwmac_parse_dt(struct imx_priv_data *dwmac, struct device *dev)
+{
+	struct device_node *np = dev->of_node;
+	int err = 0;
+
+	if (of_get_property(np, "snps,rmii_refclk_ext", NULL))
+		dwmac->rmii_refclk_ext = true;
+
+	dwmac->clk_tx = devm_clk_get(dev, "tx");
+	if (IS_ERR(dwmac->clk_tx)) {
+		dev_err(dev, "failed to get tx clock\n");
+		return PTR_ERR(dwmac->clk_tx);
+	}
+
+	dwmac->clk_mem = NULL;
+	if (of_machine_is_compatible("fsl,imx8dxl")) {
+		dwmac->clk_mem = devm_clk_get(dev, "mem");
+		if (IS_ERR(dwmac->clk_mem)) {
+			dev_err(dev, "failed to get mem clock\n");
+			return PTR_ERR(dwmac->clk_mem);
+		}
+	}
+
+	if (of_machine_is_compatible("fsl,imx8mp")) {
+		/* Binding doc describes the propety:
+		   is required by i.MX8MP.
+		   is optinoal for i.MX8DXL.
+		 */
+		dwmac->intf_regmap = syscon_regmap_lookup_by_phandle(np, "intf_mode");
+		if (IS_ERR(dwmac->intf_regmap))
+			return PTR_ERR(dwmac->intf_regmap);
+
+		err = of_property_read_u32_index(np, "intf_mode", 1, &dwmac->intf_reg_off);
+		if (err) {
+			dev_err(dev, "Can't get intf mode reg offset (%d)\n", err);
+			return err;
+		}
+	}
+
+	return err;
+}
+
+static int imx_dwmac_probe(struct platform_device *pdev)
+{
+	struct plat_stmmacenet_data *plat_dat;
+	struct stmmac_resources stmmac_res;
+	struct imx_priv_data *dwmac;
+	const struct imx_dwmac_ops *data;
+	int ret;
+
+	ret = stmmac_get_platform_resources(pdev, &stmmac_res);
+	if (ret)
+		return ret;
+
+	dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
+	if (!dwmac)
+		return PTR_ERR(dwmac);
+
+	plat_dat = stmmac_probe_config_dt(pdev, &stmmac_res.mac);
+	if (IS_ERR(plat_dat))
+		return PTR_ERR(plat_dat);
+
+	data = of_device_get_match_data(&pdev->dev);
+	if (!data) {
+		dev_err(&pdev->dev, "failed to get match data\n");
+		ret = -EINVAL;
+		goto err_match_data;
+	}
+
+	dwmac->ops = data;
+	dwmac->dev = &pdev->dev;
+
+	ret = imx_dwmac_parse_dt(dwmac, &pdev->dev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to parse OF data\n");
+		goto err_parse_dt;
+	}
+
+	ret = dma_set_mask_and_coherent(&pdev->dev,
+					DMA_BIT_MASK(dwmac->ops->addr_width));
+	if (ret) {
+		dev_err(&pdev->dev, "DMA mask set failed\n");
+		goto err_dma_mask;
+	}
+
+	plat_dat->init = imx_dwmac_init;
+	plat_dat->exit = imx_dwmac_exit;
+	plat_dat->fix_mac_speed = imx_dwmac_fix_speed;
+	plat_dat->bsp_priv = dwmac;
+	dwmac->plat_dat = plat_dat;
+
+	ret = imx_dwmac_init(pdev, dwmac);
+	if (ret)
+		goto err_dwmac_init;
+
+	ret = stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res);
+	if (ret)
+		goto err_drv_probe;
+
+	return 0;
+
+err_dwmac_init:
+err_drv_probe:
+	imx_dwmac_exit(pdev, plat_dat->bsp_priv);
+err_dma_mask:
+err_parse_dt:
+err_match_data:
+	stmmac_remove_config_dt(pdev, plat_dat);
+	return ret;
+}
+
+static struct imx_dwmac_ops imx8mp_dwmac_data = {
+	.addr_width = 34,
+	.mac_rgmii_txclk_auto_adj = false,
+	.set_intf_mode = imx8mp_set_intf_mode,
+};
+
+static struct imx_dwmac_ops imx8dxl_dwmac_data = {
+	.addr_width = 32,
+	.mac_rgmii_txclk_auto_adj = true,
+	.set_intf_mode = imx8dxl_set_intf_mode,
+};
+
+static const struct of_device_id imx_dwmac_match[] = {
+	{ .compatible = "nxp,imx8mp-dwmac-eqos", .data = &imx8mp_dwmac_data },
+	{ .compatible = "nxp,imx8dxl-dwmac-eqos", .data = &imx8dxl_dwmac_data },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, imx_dwmac_match);
+
+static struct platform_driver imx_dwmac_driver = {
+	.probe  = imx_dwmac_probe,
+	.remove = stmmac_pltfr_remove,
+	.driver = {
+		.name           = "imx-dwmac",
+		.pm		= &stmmac_pltfr_pm_ops,
+		.of_match_table = imx_dwmac_match,
+	},
+};
+module_platform_driver(imx_dwmac_driver);
+
+MODULE_AUTHOR("NXP");
+MODULE_DESCRIPTION("NXP imx8 DWMAC Specific Glue layer");
+MODULE_LICENSE("GPL v2");