net: phy: at803x: use operating parameters from PHY-specific status

Read the PHY-specific status register for the current operating mode
(speed and duplex) of the PHY.  This register reflects the actual
mode that the PHY has resolved depending on either the advertisements
of autoneg is enabled, or the forced mode if autoneg is disabled.

This ensures that phylib's software state always tracks the hardware
state.

It seems both AR8033 (which uses the AR8031 ID) and AR8035 support
this status register.  AR8030 is not known at the present time.

This patch depends on "net: phy: extract pause mode" and "net: phy:
extract link partner advertisement reading".
Reported-by: tinywrkb <tinywrkb@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: tinywrkb <tinywrkb@gmail.com>
Fixes: 5502b218 ("net: phy: use phy_resolve_aneg_linkmode in genphy_read_status")
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/at803x.c

@@ -15,6 +15,15 @@
 #include <linux/of_gpio.h>
 #include <linux/gpio/consumer.h>
 
+#define AT803X_SPECIFIC_STATUS			0x11
+#define AT803X_SS_SPEED_MASK			(3 << 14)
+#define AT803X_SS_SPEED_1000			(2 << 14)
+#define AT803X_SS_SPEED_100			(1 << 14)
+#define AT803X_SS_SPEED_10			(0 << 14)
+#define AT803X_SS_DUPLEX			BIT(13)
+#define AT803X_SS_SPEED_DUPLEX_RESOLVED		BIT(11)
+#define AT803X_SS_MDIX				BIT(6)
+
 #define AT803X_INTR_ENABLE			0x12
 #define AT803X_INTR_ENABLE_AUTONEG_ERR		BIT(15)
 #define AT803X_INTR_ENABLE_SPEED_CHANGED	BIT(14)
@@ -357,6 +366,64 @@ static int at803x_aneg_done(struct phy_device *phydev)
 	return aneg_done;
 }
 
+static int at803x_read_status(struct phy_device *phydev)
+{
+	int ss, err, old_link = phydev->link;
+
+	/* Update the link, but return if there was an error */
+	err = genphy_update_link(phydev);
+	if (err)
+		return err;
+
+	/* why bother the PHY if nothing can have changed */
+	if (phydev->autoneg == AUTONEG_ENABLE && old_link && phydev->link)
+		return 0;
+
+	phydev->speed = SPEED_UNKNOWN;
+	phydev->duplex = DUPLEX_UNKNOWN;
+	phydev->pause = 0;
+	phydev->asym_pause = 0;
+
+	err = genphy_read_lpa(phydev);
+	if (err < 0)
+		return err;
+
+	/* Read the AT8035 PHY-Specific Status register, which indicates the
+	 * speed and duplex that the PHY is actually using, irrespective of
+	 * whether we are in autoneg mode or not.
+	 */
+	ss = phy_read(phydev, AT803X_SPECIFIC_STATUS);
+	if (ss < 0)
+		return ss;
+
+	if (ss & AT803X_SS_SPEED_DUPLEX_RESOLVED) {
+		switch (ss & AT803X_SS_SPEED_MASK) {
+		case AT803X_SS_SPEED_10:
+			phydev->speed = SPEED_10;
+			break;
+		case AT803X_SS_SPEED_100:
+			phydev->speed = SPEED_100;
+			break;
+		case AT803X_SS_SPEED_1000:
+			phydev->speed = SPEED_1000;
+			break;
+		}
+		if (ss & AT803X_SS_DUPLEX)
+			phydev->duplex = DUPLEX_FULL;
+		else
+			phydev->duplex = DUPLEX_HALF;
+		if (ss & AT803X_SS_MDIX)
+			phydev->mdix = ETH_TP_MDI_X;
+		else
+			phydev->mdix = ETH_TP_MDI;
+	}
+
+	if (phydev->autoneg == AUTONEG_ENABLE && phydev->autoneg_complete)
+		phy_resolve_aneg_pause(phydev);
+
+	return 0;
+}
+
 static struct phy_driver at803x_driver[] = {
 {
 	/* ATHEROS 8035 */
@@ -370,6 +437,7 @@ static struct phy_driver at803x_driver[] = {
 	.suspend		= at803x_suspend,
 	.resume			= at803x_resume,
 	/* PHY_GBIT_FEATURES */
+	.read_status		= at803x_read_status,
 	.ack_interrupt		= at803x_ack_interrupt,
 	.config_intr		= at803x_config_intr,
 }, {
@@ -399,6 +467,7 @@ static struct phy_driver at803x_driver[] = {
 	.suspend		= at803x_suspend,
 	.resume			= at803x_resume,
 	/* PHY_GBIT_FEATURES */
+	.read_status		= at803x_read_status,
 	.aneg_done		= at803x_aneg_done,
 	.ack_interrupt		= &at803x_ack_interrupt,
 	.config_intr		= &at803x_config_intr,