net: phy: marvell: Add mdix status reporting

Report MDI-X resolved state after link up.

Tested on Linkstreet 88E6193X internal PHYs.

Signed-off-by: Paul Davey <paul.davey@alliedtelesis.co.nz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20241017015026.255224-1-paul.davey@alliedtelesis.co.nz
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/phy/marvell.c

@@ -176,6 +176,7 @@
 #define MII_M1011_PHY_STATUS_FULLDUPLEX	0x2000
 #define MII_M1011_PHY_STATUS_RESOLVED	0x0800
 #define MII_M1011_PHY_STATUS_LINK	0x0400
+#define MII_M1011_PHY_STATUS_MDIX	BIT(6)
 
 #define MII_88E3016_PHY_SPEC_CTRL	0x10
 #define MII_88E3016_DISABLE_SCRAMBLER	0x0200
@@ -1722,6 +1723,19 @@ static int marvell_read_status_page(struct phy_device *phydev, int page)
 	phydev->duplex = DUPLEX_UNKNOWN;
 	phydev->port = fiber ? PORT_FIBRE : PORT_TP;
 
+	if (fiber) {
+		phydev->mdix = ETH_TP_MDI_INVALID;
+	} else {
+		/* The MDI-X state is set regardless of Autoneg being enabled
+		 * and reflects forced MDI-X state as well as auto resolution
+		 */
+		if (status & MII_M1011_PHY_STATUS_RESOLVED)
+			phydev->mdix = status & MII_M1011_PHY_STATUS_MDIX ?
+				ETH_TP_MDI_X : ETH_TP_MDI;
+		else
+			phydev->mdix = ETH_TP_MDI_INVALID;
+	}
+
 	if (phydev->autoneg == AUTONEG_ENABLE)
 		err = marvell_read_status_page_an(phydev, fiber, status);
 	else