amd-xgbe: Add support for 10 Mbps speed

Add the necessary changes to support 10 Mbps speed for BaseT and SFP
port modes. This is supported in MAC ver >= 30H.
Signed-off-by: Raju Rangoju <Raju.Rangoju@amd.com>
Link: https://lore.kernel.org/r/20230109101819.747572-1-Raju.Rangoju@amd.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/amd/xgbe/xgbe-dev.c

@@ -807,6 +807,9 @@ static int xgbe_set_speed(struct xgbe_prv_data *pdata, int speed)
 	unsigned int ss;
 
 	switch (speed) {
+	case SPEED_10:
+		ss = 0x07;
+		break;
 	case SPEED_1000:
 		ss = 0x03;
 		break;

drivers/net/ethernet/amd/xgbe/xgbe-mdio.c

@@ -274,6 +274,15 @@ static void xgbe_sgmii_1000_mode(struct xgbe_prv_data *pdata)
 	pdata->phy_if.phy_impl.set_mode(pdata, XGBE_MODE_SGMII_1000);
 }
 
+static void xgbe_sgmii_10_mode(struct xgbe_prv_data *pdata)
+{
+	/* Set MAC to 10M speed */
+	pdata->hw_if.set_speed(pdata, SPEED_10);
+
+	/* Call PHY implementation support to complete rate change */
+	pdata->phy_if.phy_impl.set_mode(pdata, XGBE_MODE_SGMII_10);
+}
+
 static void xgbe_sgmii_100_mode(struct xgbe_prv_data *pdata)
 {
 	/* Set MAC to 1G speed */
@@ -306,6 +315,9 @@ static void xgbe_change_mode(struct xgbe_prv_data *pdata,
 	case XGBE_MODE_KR:
 		xgbe_kr_mode(pdata);
 		break;
+	case XGBE_MODE_SGMII_10:
+		xgbe_sgmii_10_mode(pdata);
+		break;
 	case XGBE_MODE_SGMII_100:
 		xgbe_sgmii_100_mode(pdata);
 		break;
@@ -1074,6 +1086,8 @@ static const char *xgbe_phy_fc_string(struct xgbe_prv_data *pdata)
 static const char *xgbe_phy_speed_string(int speed)
 {
 	switch (speed) {
+	case SPEED_10:
+		return "10Mbps";
 	case SPEED_100:
 		return "100Mbps";
 	case SPEED_1000:
@@ -1161,6 +1175,7 @@ static int xgbe_phy_config_fixed(struct xgbe_prv_data *pdata)
 	case XGBE_MODE_KX_1000:
 	case XGBE_MODE_KX_2500:
 	case XGBE_MODE_KR:
+	case XGBE_MODE_SGMII_10:
 	case XGBE_MODE_SGMII_100:
 	case XGBE_MODE_SGMII_1000:
 	case XGBE_MODE_X:
@@ -1222,6 +1237,8 @@ static int __xgbe_phy_config_aneg(struct xgbe_prv_data *pdata, bool set_mode)
 			xgbe_set_mode(pdata, XGBE_MODE_SGMII_1000);
 		} else if (xgbe_use_mode(pdata, XGBE_MODE_SGMII_100)) {
 			xgbe_set_mode(pdata, XGBE_MODE_SGMII_100);
+		} else if (xgbe_use_mode(pdata, XGBE_MODE_SGMII_10)) {
+			xgbe_set_mode(pdata, XGBE_MODE_SGMII_10);
 		} else {
 			enable_irq(pdata->an_irq);
 			ret = -EINVAL;
@@ -1301,6 +1318,9 @@ static void xgbe_phy_status_result(struct xgbe_prv_data *pdata)
 		mode = xgbe_phy_status_aneg(pdata);
 
 	switch (mode) {
+	case XGBE_MODE_SGMII_10:
+		pdata->phy.speed = SPEED_10;
+		break;
 	case XGBE_MODE_SGMII_100:
 		pdata->phy.speed = SPEED_100;
 		break;
@@ -1443,6 +1463,8 @@ static int xgbe_phy_start(struct xgbe_prv_data *pdata)
 		xgbe_sgmii_1000_mode(pdata);
 	} else if (xgbe_use_mode(pdata, XGBE_MODE_SGMII_100)) {
 		xgbe_sgmii_100_mode(pdata);
+	} else if (xgbe_use_mode(pdata, XGBE_MODE_SGMII_10)) {
+		xgbe_sgmii_10_mode(pdata);
 	} else {
 		ret = -EINVAL;
 		goto err_irq;
@@ -1540,6 +1562,8 @@ static int xgbe_phy_best_advertised_speed(struct xgbe_prv_data *pdata)
 		return SPEED_1000;
 	else if (XGBE_ADV(lks, 100baseT_Full))
 		return SPEED_100;
+	else if (XGBE_ADV(lks, 10baseT_Full))
+		return SPEED_10;
 
 	return SPEED_UNKNOWN;
 }

drivers/net/ethernet/amd/xgbe/xgbe.h

@@ -293,6 +293,7 @@
 
 #define XGBE_SGMII_AN_LINK_STATUS	BIT(1)
 #define XGBE_SGMII_AN_LINK_SPEED	(BIT(2) | BIT(3))
+#define XGBE_SGMII_AN_LINK_SPEED_10	0x00
 #define XGBE_SGMII_AN_LINK_SPEED_100	0x04
 #define XGBE_SGMII_AN_LINK_SPEED_1000	0x08
 #define XGBE_SGMII_AN_LINK_DUPLEX	BIT(4)
@@ -594,6 +595,7 @@ enum xgbe_mode {
 	XGBE_MODE_KX_2500,
 	XGBE_MODE_KR,
 	XGBE_MODE_X,
+	XGBE_MODE_SGMII_10,
 	XGBE_MODE_SGMII_100,
 	XGBE_MODE_SGMII_1000,
 	XGBE_MODE_SFI,