net: phy: Add detection of 1000BaseX link mode support

Add 1000BaseX to the link modes which are detected based on the
MII_ESTATUS register as per 802.3 Clause 22. This allows PHYs which
support 1000BaseX to work properly with drivers using phylink.

Previously 1000BaseX support was not detected, and if that was the only
mode the PHY indicated support for, phylink would refuse to attach it
due to the list of supported modes being empty.
Signed-off-by: Robert Hancock <hancock@sedsystems.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/phy_device.c

@@ -1930,6 +1930,9 @@ int genphy_config_init(struct phy_device *phydev)
 		if (val & ESTATUS_1000_THALF)
 			linkmode_set_bit(ETHTOOL_LINK_MODE_1000baseT_Half_BIT,
 					 features);
+		if (val & ESTATUS_1000_XFULL)
+			linkmode_set_bit(ETHTOOL_LINK_MODE_1000baseX_Full_BIT,
+					 features);
 	}
 
 	linkmode_and(phydev->supported, phydev->supported, features);

include/uapi/linux/mii.h

@@ -121,6 +121,8 @@
 #define EXPANSION_MFAULTS	0x0010	/* Multiple faults detected    */
 #define EXPANSION_RESV		0xffe0	/* Unused...                   */
 
+#define ESTATUS_1000_XFULL	0x8000	/* Can do 1000BaseX Full       */
+#define ESTATUS_1000_XHALF	0x4000	/* Can do 1000BaseX Half       */
 #define ESTATUS_1000_TFULL	0x2000	/* Can do 1000BT Full          */
 #define ESTATUS_1000_THALF	0x1000	/* Can do 1000BT Half          */