net: stmmac: Add glue layer for T-HEAD TH1520 SoC

Add dwmac glue driver to support the DesignWare-based GMAC controllers
on the T-HEAD TH1520 SoC.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Signed-off-by: Drew Fustini <dfustini@tenstorrent.com>
Link: https://patch.msgid.link/20241103-th1520-gmac-v7-2-ef094a30169c@tenstorrent.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

3 files changed, 284 insertions, 0 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
index 05cc07b8f48c..6658536a4e17 100644
--- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
+++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
@@ -228,6 +228,16 @@ config DWMAC_SUN8I
 	  stmmac device driver. This driver is used for H3/A83T/A64
 	  EMAC ethernet controller.
 
+config DWMAC_THEAD
+	tristate "T-HEAD dwmac support"
+	depends on OF && (ARCH_THEAD || COMPILE_TEST)
+	help
+	  Support for ethernet controllers on T-HEAD RISC-V SoCs
+
+	  This selects the T-HEAD platform specific glue layer support for
+	  the stmmac device driver. This driver is used for T-HEAD TH1520
+	  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 7e46dca90628..2389fd261344 100644
--- a/drivers/net/ethernet/stmicro/stmmac/Makefile
+++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
@@ -28,6 +28,7 @@ obj-$(CONFIG_DWMAC_STI)		+= dwmac-sti.o
 obj-$(CONFIG_DWMAC_STM32)	+= dwmac-stm32.o
 obj-$(CONFIG_DWMAC_SUNXI)	+= dwmac-sunxi.o
 obj-$(CONFIG_DWMAC_SUN8I)	+= dwmac-sun8i.o
+obj-$(CONFIG_DWMAC_THEAD)	+= dwmac-thead.o
 obj-$(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-thead.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
new file mode 100644
index 000000000000..dce84ed184e9
--- /dev/null
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
@@ -0,0 +1,273 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * T-HEAD DWMAC platform driver
+ *
+ * Copyright (C) 2021 Alibaba Group Holding Limited.
+ * Copyright (C) 2023 Jisheng Zhang <jszhang@kernel.org>
+ *
+ */
+
+#include <linux/bitfield.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_net.h>
+#include <linux/platform_device.h>
+
+#include "stmmac_platform.h"
+
+#define GMAC_CLK_EN			0x00
+#define  GMAC_TX_CLK_EN			BIT(1)
+#define  GMAC_TX_CLK_N_EN		BIT(2)
+#define  GMAC_TX_CLK_OUT_EN		BIT(3)
+#define  GMAC_RX_CLK_EN			BIT(4)
+#define  GMAC_RX_CLK_N_EN		BIT(5)
+#define  GMAC_EPHY_REF_CLK_EN		BIT(6)
+#define GMAC_RXCLK_DELAY_CTRL		0x04
+#define  GMAC_RXCLK_BYPASS		BIT(15)
+#define  GMAC_RXCLK_INVERT		BIT(14)
+#define  GMAC_RXCLK_DELAY		GENMASK(4, 0)
+#define GMAC_TXCLK_DELAY_CTRL		0x08
+#define  GMAC_TXCLK_BYPASS		BIT(15)
+#define  GMAC_TXCLK_INVERT		BIT(14)
+#define  GMAC_TXCLK_DELAY		GENMASK(4, 0)
+#define GMAC_PLLCLK_DIV			0x0c
+#define  GMAC_PLLCLK_DIV_EN		BIT(31)
+#define  GMAC_PLLCLK_DIV_NUM		GENMASK(7, 0)
+#define GMAC_GTXCLK_SEL			0x18
+#define  GMAC_GTXCLK_SEL_PLL		BIT(0)
+#define GMAC_INTF_CTRL			0x1c
+#define  PHY_INTF_MASK			BIT(0)
+#define  PHY_INTF_RGMII			FIELD_PREP(PHY_INTF_MASK, 1)
+#define  PHY_INTF_MII_GMII		FIELD_PREP(PHY_INTF_MASK, 0)
+#define GMAC_TXCLK_OEN			0x20
+#define  TXCLK_DIR_MASK			BIT(0)
+#define  TXCLK_DIR_OUTPUT		FIELD_PREP(TXCLK_DIR_MASK, 0)
+#define  TXCLK_DIR_INPUT		FIELD_PREP(TXCLK_DIR_MASK, 1)
+
+#define GMAC_GMII_RGMII_RATE	125000000
+#define GMAC_MII_RATE		25000000
+
+struct thead_dwmac {
+	struct plat_stmmacenet_data *plat;
+	void __iomem *apb_base;
+	struct device *dev;
+};
+
+static int thead_dwmac_set_phy_if(struct plat_stmmacenet_data *plat)
+{
+	struct thead_dwmac *dwmac = plat->bsp_priv;
+	u32 phyif;
+
+	switch (plat->mac_interface) {
+	case PHY_INTERFACE_MODE_MII:
+		phyif = PHY_INTF_MII_GMII;
+		break;
+	case PHY_INTERFACE_MODE_RGMII:
+	case PHY_INTERFACE_MODE_RGMII_ID:
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+	case PHY_INTERFACE_MODE_RGMII_RXID:
+		phyif = PHY_INTF_RGMII;
+		break;
+	default:
+		dev_err(dwmac->dev, "unsupported phy interface %d\n",
+			plat->mac_interface);
+		return -EINVAL;
+	}
+
+	writel(phyif, dwmac->apb_base + GMAC_INTF_CTRL);
+	return 0;
+}
+
+static int thead_dwmac_set_txclk_dir(struct plat_stmmacenet_data *plat)
+{
+	struct thead_dwmac *dwmac = plat->bsp_priv;
+	u32 txclk_dir;
+
+	switch (plat->mac_interface) {
+	case PHY_INTERFACE_MODE_MII:
+		txclk_dir = TXCLK_DIR_INPUT;
+		break;
+	case PHY_INTERFACE_MODE_RGMII:
+	case PHY_INTERFACE_MODE_RGMII_ID:
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+	case PHY_INTERFACE_MODE_RGMII_RXID:
+		txclk_dir = TXCLK_DIR_OUTPUT;
+		break;
+	default:
+		dev_err(dwmac->dev, "unsupported phy interface %d\n",
+			plat->mac_interface);
+		return -EINVAL;
+	}
+
+	writel(txclk_dir, dwmac->apb_base + GMAC_TXCLK_OEN);
+	return 0;
+}
+
+static void thead_dwmac_fix_speed(void *priv, unsigned int speed, unsigned int mode)
+{
+	struct plat_stmmacenet_data *plat;
+	struct thead_dwmac *dwmac = priv;
+	unsigned long rate;
+	u32 div, reg;
+
+	plat = dwmac->plat;
+
+	switch (plat->mac_interface) {
+	/* For MII, rxc/txc is provided by phy */
+	case PHY_INTERFACE_MODE_MII:
+		return;
+
+	case PHY_INTERFACE_MODE_RGMII:
+	case PHY_INTERFACE_MODE_RGMII_ID:
+	case PHY_INTERFACE_MODE_RGMII_RXID:
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+		rate = clk_get_rate(plat->stmmac_clk);
+		if (!rate || rate % GMAC_GMII_RGMII_RATE != 0 ||
+		    rate % GMAC_MII_RATE != 0) {
+			dev_err(dwmac->dev, "invalid gmac rate %ld\n", rate);
+			return;
+		}
+
+		writel(0, dwmac->apb_base + GMAC_PLLCLK_DIV);
+
+		switch (speed) {
+		case SPEED_1000:
+			div = rate / GMAC_GMII_RGMII_RATE;
+			break;
+		case SPEED_100:
+			div = rate / GMAC_MII_RATE;
+			break;
+		case SPEED_10:
+			div = rate * 10 / GMAC_MII_RATE;
+			break;
+		default:
+			dev_err(dwmac->dev, "invalid speed %u\n", speed);
+			return;
+		}
+
+		reg = FIELD_PREP(GMAC_PLLCLK_DIV_EN, 1) |
+		      FIELD_PREP(GMAC_PLLCLK_DIV_NUM, div);
+		writel(reg, dwmac->apb_base + GMAC_PLLCLK_DIV);
+		break;
+	default:
+		dev_err(dwmac->dev, "unsupported phy interface %d\n",
+			plat->mac_interface);
+		return;
+	}
+}
+
+static int thead_dwmac_enable_clk(struct plat_stmmacenet_data *plat)
+{
+	struct thead_dwmac *dwmac = plat->bsp_priv;
+	u32 reg;
+
+	switch (plat->mac_interface) {
+	case PHY_INTERFACE_MODE_MII:
+		reg = GMAC_RX_CLK_EN | GMAC_TX_CLK_EN;
+		break;
+
+	case PHY_INTERFACE_MODE_RGMII:
+	case PHY_INTERFACE_MODE_RGMII_ID:
+	case PHY_INTERFACE_MODE_RGMII_RXID:
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+		/* use pll */
+		writel(GMAC_GTXCLK_SEL_PLL, dwmac->apb_base + GMAC_GTXCLK_SEL);
+		reg = GMAC_TX_CLK_EN | GMAC_TX_CLK_N_EN | GMAC_TX_CLK_OUT_EN |
+		      GMAC_RX_CLK_EN | GMAC_RX_CLK_N_EN;
+		break;
+
+	default:
+		dev_err(dwmac->dev, "unsupported phy interface %d\n",
+			plat->mac_interface);
+		return -EINVAL;
+	}
+
+	writel(reg, dwmac->apb_base + GMAC_CLK_EN);
+	return 0;
+}
+
+static int thead_dwmac_init(struct platform_device *pdev, void *priv)
+{
+	struct thead_dwmac *dwmac = priv;
+	unsigned int reg;
+	int ret;
+
+	ret = thead_dwmac_set_phy_if(dwmac->plat);
+	if (ret)
+		return ret;
+
+	ret = thead_dwmac_set_txclk_dir(dwmac->plat);
+	if (ret)
+		return ret;
+
+	reg = readl(dwmac->apb_base + GMAC_RXCLK_DELAY_CTRL);
+	reg &= ~(GMAC_RXCLK_DELAY);
+	reg |= FIELD_PREP(GMAC_RXCLK_DELAY, 0);
+	writel(reg, dwmac->apb_base + GMAC_RXCLK_DELAY_CTRL);
+
+	reg = readl(dwmac->apb_base + GMAC_TXCLK_DELAY_CTRL);
+	reg &= ~(GMAC_TXCLK_DELAY);
+	reg |= FIELD_PREP(GMAC_TXCLK_DELAY, 0);
+	writel(reg, dwmac->apb_base + GMAC_TXCLK_DELAY_CTRL);
+
+	return thead_dwmac_enable_clk(dwmac->plat);
+}
+
+static int thead_dwmac_probe(struct platform_device *pdev)
+{
+	struct stmmac_resources stmmac_res;
+	struct plat_stmmacenet_data *plat;
+	struct thead_dwmac *dwmac;
+	void __iomem *apb;
+	int ret;
+
+	ret = stmmac_get_platform_resources(pdev, &stmmac_res);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret,
+				     "failed to get resources\n");
+
+	plat = devm_stmmac_probe_config_dt(pdev, stmmac_res.mac);
+	if (IS_ERR(plat))
+		return dev_err_probe(&pdev->dev, PTR_ERR(plat),
+				     "dt configuration failed\n");
+
+	dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
+	if (!dwmac)
+		return -ENOMEM;
+
+	apb = devm_platform_ioremap_resource(pdev, 1);
+	if (IS_ERR(apb))
+		return dev_err_probe(&pdev->dev, PTR_ERR(apb),
+				     "failed to remap gmac apb registers\n");
+
+	dwmac->dev = &pdev->dev;
+	dwmac->plat = plat;
+	dwmac->apb_base = apb;
+	plat->bsp_priv = dwmac;
+	plat->fix_mac_speed = thead_dwmac_fix_speed;
+	plat->init = thead_dwmac_init;
+
+	return devm_stmmac_pltfr_probe(pdev, plat, &stmmac_res);
+}
+
+static const struct of_device_id thead_dwmac_match[] = {
+	{ .compatible = "thead,th1520-gmac" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, thead_dwmac_match);
+
+static struct platform_driver thead_dwmac_driver = {
+	.probe = thead_dwmac_probe,
+	.driver = {
+		.name = "thead-dwmac",
+		.pm = &stmmac_pltfr_pm_ops,
+		.of_match_table = thead_dwmac_match,
+	},
+};
+module_platform_driver(thead_dwmac_driver);
+
+MODULE_AUTHOR("Jisheng Zhang <jszhang@kernel.org>");
+MODULE_AUTHOR("Drew Fustini <drew@pdp7.com>");
+MODULE_DESCRIPTION("T-HEAD DWMAC platform driver");
+MODULE_LICENSE("GPL");