net: stmmac: dwmac-qcom-ethqos: add support for SGMII

On sa8775p the MAC is connected to the external PHY over SGMII so add
support for it to the driver.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c

@@ -75,6 +75,10 @@
 #define RGMII_CONFIG2_DATA_DIVIDE_CLK_SEL	BIT(6)
 #define RGMII_CONFIG2_TX_CLK_PHASE_SHIFT_EN	BIT(5)
 
+/* MAC_CTRL_REG bits */
+#define ETHQOS_MAC_CTRL_SPEED_MODE		BIT(14)
+#define ETHQOS_MAC_CTRL_PORT_SEL		BIT(15)
+
 struct ethqos_emac_por {
 	unsigned int offset;
 	unsigned int value;
@@ -92,6 +96,7 @@ struct ethqos_emac_driver_data {
 struct qcom_ethqos {
 	struct platform_device *pdev;
 	void __iomem *rgmii_base;
+	void __iomem *mac_base;
 	int (*configure_func)(struct qcom_ethqos *ethqos);
 
 	unsigned int link_clk_rate;
@@ -559,6 +564,33 @@ static int ethqos_configure_rgmii(struct qcom_ethqos *ethqos)
 	return 0;
 }
 
+static int ethqos_configure_sgmii(struct qcom_ethqos *ethqos)
+{
+	int val;
+
+	val = readl(ethqos->mac_base + MAC_CTRL_REG);
+
+	switch (ethqos->speed) {
+	case SPEED_1000:
+		val &= ~ETHQOS_MAC_CTRL_PORT_SEL;
+		rgmii_updatel(ethqos, RGMII_CONFIG2_RGMII_CLK_SEL_CFG,
+			      RGMII_CONFIG2_RGMII_CLK_SEL_CFG,
+			      RGMII_IO_MACRO_CONFIG2);
+		break;
+	case SPEED_100:
+		val |= ETHQOS_MAC_CTRL_PORT_SEL | ETHQOS_MAC_CTRL_SPEED_MODE;
+		break;
+	case SPEED_10:
+		val |= ETHQOS_MAC_CTRL_PORT_SEL;
+		val &= ~ETHQOS_MAC_CTRL_SPEED_MODE;
+		break;
+	}
+
+	writel(val, ethqos->mac_base + MAC_CTRL_REG);
+
+	return val;
+}
+
 static int ethqos_configure(struct qcom_ethqos *ethqos)
 {
 	return ethqos->configure_func(ethqos);
@@ -663,6 +695,9 @@ static int qcom_ethqos_probe(struct platform_device *pdev)
 	case PHY_INTERFACE_MODE_RGMII_TXID:
 		ethqos->configure_func = ethqos_configure_rgmii;
 		break;
+	case PHY_INTERFACE_MODE_SGMII:
+		ethqos->configure_func = ethqos_configure_sgmii;
+		break;
 	case -ENODEV:
 		ret = -ENODEV;
 		goto out_config_dt;
@@ -678,6 +713,8 @@ static int qcom_ethqos_probe(struct platform_device *pdev)
 		goto out_config_dt;
 	}
 
+	ethqos->mac_base = stmmac_res.addr;
+
 	data = of_device_get_match_data(dev);
 	ethqos->por = data->por;
 	ethqos->num_por = data->num_por;