[PATCH 7/7] net: stmmac: dwc-qos: Add Tegra186 support

[Thierry Reding <thierry.reding@gmail.com>]

From: Thierry Reding <treding@nvidia.com>

The NVIDIA Tegra186 SoC contains an instance of the Synopsys DWC
ethernet QOS IP core. The binding that it uses is slightly different
from existing ones because of the integration (clocks, resets, ...).

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 .../ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c    | 252 +++++++++++++++++++++
 1 file changed, 252 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
index 5071d3c15adc..54dfbdc48f6d 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
@@ -14,6 +14,7 @@
 #include <linux/clk.h>
 #include <linux/clk-provider.h>
 #include <linux/device.h>
+#include <linux/gpio/consumer.h>
 #include <linux/ethtool.h>
 #include <linux/io.h>
 #include <linux/ioport.h>
@@ -22,10 +23,24 @@
 #include <linux/of_net.h>
 #include <linux/mfd/syscon.h>
 #include <linux/platform_device.h>
+#include <linux/reset.h>
 #include <linux/stmmac.h>
 
 #include "stmmac_platform.h"
 
+struct tegra_eqos {
+	struct device *dev;
+	void __iomem *regs;
+
+	struct reset_control *rst;
+	struct clk *clk_master;
+	struct clk *clk_slave;
+	struct clk *clk_tx;
+	struct clk *clk_rx;
+
+	struct gpio_desc *reset;
+};
+
 static int dwc_eth_dwmac_config_dt(struct platform_device *pdev,
 				   struct plat_stmmacenet_data *plat_dat)
 {
@@ -148,6 +163,237 @@ static int dwc_qos_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#define SDMEMCOMPPADCTRL 0x8800
+#define  SDMEMCOMPPADCTRL_PAD_E_INPUT_OR_E_PWRD BIT(31)
+
+#define AUTO_CAL_CONFIG 0x8804
+#define  AUTO_CAL_CONFIG_START BIT(31)
+#define  AUTO_CAL_CONFIG_ENABLE BIT(29)
+
+#define AUTO_CAL_STATUS 0x880c
+#define  AUTO_CAL_STATUS_ACTIVE BIT(31)
+
+static void tegra_eqos_fix_speed(void *priv, unsigned int speed)
+{
+	struct tegra_eqos *eqos = priv;
+	unsigned long rate = 125000000;
+	bool needs_calibration = false;
+	unsigned int i;
+	u32 value;
+
+	switch (speed) {
+	case SPEED_1000:
+		needs_calibration = true;
+		rate = 125000000;
+		break;
+
+	case SPEED_100:
+		needs_calibration = true;
+		rate = 25000000;
+		break;
+
+	case SPEED_10:
+		rate = 2500000;
+		break;
+
+	default:
+		dev_err(eqos->dev, "invalid speed %u\n", speed);
+		break;
+	}
+
+	if (needs_calibration) {
+		/* calibrate */
+		value = readl(eqos->regs + SDMEMCOMPPADCTRL);
+		value |= SDMEMCOMPPADCTRL_PAD_E_INPUT_OR_E_PWRD;
+		writel(value, eqos->regs + SDMEMCOMPPADCTRL);
+
+		udelay(1);
+
+		value = readl(eqos->regs + AUTO_CAL_CONFIG);
+		value |= AUTO_CAL_CONFIG_START | AUTO_CAL_CONFIG_ENABLE;
+		writel(value, eqos->regs + AUTO_CAL_CONFIG);
+
+		for (i = 0; i <= 10; i++) {
+			value = readl(eqos->regs + AUTO_CAL_STATUS);
+			if (value & AUTO_CAL_STATUS_ACTIVE)
+				break;
+
+			udelay(1);
+		}
+
+		if ((value & AUTO_CAL_STATUS_ACTIVE) == 0) {
+			dev_err(eqos->dev, "calibration did not start\n");
+			goto failed;
+		}
+
+		for (i = 0; i <= 10; i++) {
+			value = readl(eqos->regs + AUTO_CAL_STATUS);
+			if ((value & AUTO_CAL_STATUS_ACTIVE) == 0)
+				break;
+
+			udelay(20);
+		}
+
+		if (value & AUTO_CAL_STATUS_ACTIVE) {
+			dev_err(eqos->dev, "calibration didn't finish\n");
+			goto failed;
+		}
+
+	failed:
+		value = readl(eqos->regs + SDMEMCOMPPADCTRL);
+		value &= ~SDMEMCOMPPADCTRL_PAD_E_INPUT_OR_E_PWRD;
+		writel(value, eqos->regs + SDMEMCOMPPADCTRL);
+	} else {
+		value = readl(eqos->regs + AUTO_CAL_CONFIG);
+		value &= ~AUTO_CAL_CONFIG_ENABLE;
+		writel(value, eqos->regs + AUTO_CAL_CONFIG);
+	}
+
+	clk_set_rate(eqos->clk_tx, rate);
+}
+
+static int tegra_eqos_init(struct platform_device *pdev, void *priv)
+{
+	struct tegra_eqos *eqos = priv;
+	unsigned long rate;
+	u32 value;
+
+	rate = clk_get_rate(eqos->clk_slave);
+
+	value = readl(eqos->regs + 0xdc);
+	value = (rate / 1000000) - 1;
+	writel(value, eqos->regs + 0xdc);
+
+	return 0;
+}
+
+static void *tegra_eqos_probe(struct platform_device *pdev,
+			      struct plat_stmmacenet_data *data,
+			      struct stmmac_resources *res)
+{
+	struct tegra_eqos *eqos;
+	int err;
+
+	eqos = devm_kzalloc(&pdev->dev, sizeof(*eqos), GFP_KERNEL);
+	if (!eqos) {
+		err = -ENOMEM;
+		goto error;
+	}
+
+	eqos->dev = &pdev->dev;
+	eqos->regs = res->addr;
+
+	eqos->clk_master = devm_clk_get(&pdev->dev, "master_bus");
+	if (IS_ERR(eqos->clk_master)) {
+		err = PTR_ERR(eqos->clk_master);
+		goto error;
+	}
+
+	err = clk_prepare_enable(eqos->clk_master);
+	if (err < 0)
+		goto error;
+
+	eqos->clk_slave = devm_clk_get(&pdev->dev, "slave_bus");
+	if (IS_ERR(eqos->clk_slave)) {
+		err = PTR_ERR(eqos->clk_slave);
+		goto disable_master;
+	}
+
+	data->stmmac_clk = eqos->clk_slave;
+
+	err = clk_prepare_enable(eqos->clk_slave);
+	if (err < 0)
+		goto disable_master;
+
+	eqos->clk_rx = devm_clk_get(&pdev->dev, "rx");
+	if (IS_ERR(eqos->clk_rx)) {
+		err = PTR_ERR(eqos->clk_rx);
+		goto disable_slave;
+	}
+
+	err = clk_prepare_enable(eqos->clk_rx);
+	if (err < 0)
+		goto disable_slave;
+
+	eqos->clk_tx = devm_clk_get(&pdev->dev, "tx");
+	if (IS_ERR(eqos->clk_tx)) {
+		err = PTR_ERR(eqos->clk_tx);
+		goto disable_rx;
+	}
+
+	err = clk_prepare_enable(eqos->clk_tx);
+	if (err < 0)
+		goto disable_rx;
+
+	eqos->reset = devm_gpiod_get(&pdev->dev, "phy-reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(eqos->reset)) {
+		err = PTR_ERR(eqos->reset);
+		goto disable_tx;
+	}
+
+	usleep_range(2000, 4000);
+	gpiod_set_value(eqos->reset, 0);
+
+	eqos->rst = devm_reset_control_get(&pdev->dev, "eqos");
+	if (IS_ERR(eqos->rst)) {
+		err = PTR_ERR(eqos->rst);
+		goto reset_phy;
+	}
+
+	err = reset_control_assert(eqos->rst);
+	if (err < 0)
+		goto reset_phy;
+
+	usleep_range(2000, 4000);
+
+	err = reset_control_deassert(eqos->rst);
+	if (err < 0)
+		goto reset_phy;
+
+	usleep_range(2000, 4000);
+
+	data->fix_mac_speed = tegra_eqos_fix_speed;
+	data->init = tegra_eqos_init;
+	data->bsp_priv = eqos;
+
+	err = tegra_eqos_init(pdev, eqos);
+	if (err < 0)
+		goto reset;
+
+out:
+	return eqos;
+
+reset:
+	reset_control_assert(eqos->rst);
+reset_phy:
+	gpiod_set_value(eqos->reset, 1);
+disable_tx:
+	clk_disable_unprepare(eqos->clk_tx);
+disable_rx:
+	clk_disable_unprepare(eqos->clk_rx);
+disable_slave:
+	clk_disable_unprepare(eqos->clk_slave);
+disable_master:
+	clk_disable_unprepare(eqos->clk_master);
+error:
+	eqos = ERR_PTR(err);
+	goto out;
+}
+
+static int tegra_eqos_remove(struct platform_device *pdev)
+{
+	struct tegra_eqos *eqos = get_stmmac_bsp_priv(&pdev->dev);
+
+	reset_control_assert(eqos->rst);
+	gpiod_set_value(eqos->reset, 1);
+	clk_disable_unprepare(eqos->clk_tx);
+	clk_disable_unprepare(eqos->clk_rx);
+	clk_disable_unprepare(eqos->clk_slave);
+	clk_disable_unprepare(eqos->clk_master);
+
+	return 0;
+}
+
 struct dwc_eth_dwmac_data {
 	void *(*probe)(struct platform_device *pdev,
 		       struct plat_stmmacenet_data *data,
@@ -160,6 +406,11 @@ static const struct dwc_eth_dwmac_data dwc_qos_data = {
 	.remove = dwc_qos_remove,
 };
 
+static const struct dwc_eth_dwmac_data tegra_eqos_data = {
+	.probe = tegra_eqos_probe,
+	.remove = tegra_eqos_remove,
+};
+
 static int dwc_eth_dwmac_probe(struct platform_device *pdev)
 {
 	const struct dwc_eth_dwmac_data *data;
@@ -245,6 +496,7 @@ static int dwc_eth_dwmac_remove(struct platform_device *pdev)
 
 static const struct of_device_id dwc_eth_dwmac_match[] = {
 	{ .compatible = "snps,dwc-qos-ethernet-4.10", .data = &dwc_qos_data },
+	{ .compatible = "nvidia,tegra186-eqos", .data = &tegra_eqos_data},
 	{ }
 };
 MODULE_DEVICE_TABLE(of, dwc_eth_dwmac_match);
-- 
2.11.1