net: stmmac: dwmac-qcom-ethqos: Adjust rgmii loopback_en per platform

Not all platforms should have RGMII_CONFIG_LOOPBACK_EN and the result it
about 50% packet loss on incoming messages. So make it possile to
configure this per compatible and enable it for QCS404.

Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -78,6 +78,7 @@ struct ethqos_emac_por {
 struct ethqos_emac_driver_data {
 	const struct ethqos_emac_por *por;
 	unsigned int num_por;
+	bool rgmii_config_looback_en;
 };
 
 struct qcom_ethqos {
@@ -90,6 +91,7 @@ struct qcom_ethqos {
 
 	const struct ethqos_emac_por *por;
 	unsigned int num_por;
+	bool rgmii_config_looback_en;
 };
 
 static int rgmii_readl(struct qcom_ethqos *ethqos, unsigned int offset)
@@ -181,6 +183,7 @@ static const struct ethqos_emac_por emac_v2_3_0_por[] = {
 static const struct ethqos_emac_driver_data emac_v2_3_0_data = {
 	.por = emac_v2_3_0_por,
 	.num_por = ARRAY_SIZE(emac_v2_3_0_por),
+	.rgmii_config_looback_en = true,
 };
 
 static const struct ethqos_emac_por emac_v2_1_0_por[] = {
@@ -195,6 +198,7 @@ static const struct ethqos_emac_por emac_v2_1_0_por[] = {
 static const struct ethqos_emac_driver_data emac_v2_1_0_data = {
 	.por = emac_v2_1_0_por,
 	.num_por = ARRAY_SIZE(emac_v2_1_0_por),
+	.rgmii_config_looback_en = false,
 };
 
 static int ethqos_dll_configure(struct qcom_ethqos *ethqos)
@@ -311,8 +315,12 @@ static int ethqos_rgmii_macro_init(struct qcom_ethqos *ethqos)
 		rgmii_updatel(ethqos, SDCC_DDR_CONFIG_PRG_DLY_EN,
 			      SDCC_DDR_CONFIG_PRG_DLY_EN,
 			      SDCC_HC_REG_DDR_CONFIG);
+		if (ethqos->rgmii_config_looback_en)
 			rgmii_updatel(ethqos, RGMII_CONFIG_LOOPBACK_EN,
 				      RGMII_CONFIG_LOOPBACK_EN, RGMII_IO_MACRO_CONFIG);
+		else
+			rgmii_updatel(ethqos, RGMII_CONFIG_LOOPBACK_EN,
+				      0, RGMII_IO_MACRO_CONFIG);
 		break;
 
 	case SPEED_100:
@@ -345,8 +353,13 @@ static int ethqos_rgmii_macro_init(struct qcom_ethqos *ethqos)
 		rgmii_updatel(ethqos, SDCC_DDR_CONFIG_EXT_PRG_RCLK_DLY_EN,
 			      SDCC_DDR_CONFIG_EXT_PRG_RCLK_DLY_EN,
 			      SDCC_HC_REG_DDR_CONFIG);
+		if (ethqos->rgmii_config_looback_en)
 			rgmii_updatel(ethqos, RGMII_CONFIG_LOOPBACK_EN,
 				      RGMII_CONFIG_LOOPBACK_EN, RGMII_IO_MACRO_CONFIG);
+		else
+			rgmii_updatel(ethqos, RGMII_CONFIG_LOOPBACK_EN,
+				      0, RGMII_IO_MACRO_CONFIG);
+
 		break;
 
 	case SPEED_10:
@@ -518,6 +531,7 @@ static int qcom_ethqos_probe(struct platform_device *pdev)
 	data = of_device_get_match_data(&pdev->dev);
 	ethqos->por = data->por;
 	ethqos->num_por = data->num_por;
+	ethqos->rgmii_config_looback_en = data->rgmii_config_looback_en;
 
 	ethqos->rgmii_clk = devm_clk_get(&pdev->dev, "rgmii");
 	if (IS_ERR(ethqos->rgmii_clk)) {