net: phy: marvell: add errata w/a for 88E151* chips

As per Marvell Release Notes - Alaska 88E1510/88E1518/88E1512/88E1514
Rev A0, Errata Section 3.1 Marvell PHY has an errata which requires
that certain registers get written in order to restart
autonegotiation.

Signed-off-by: Hao Zhang <hzhang@ti.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
Reviewed-by: Stefan Roese <sr@denx.de>

drivers/net/phy/marvell.c

@@ -276,6 +276,57 @@ static int m88e1111s_config(struct phy_device *phydev)
 	return 0;
 }
 
+/**
+ * m88e1518_phy_writebits - write bits to a register
+ */
+void m88e1518_phy_writebits(struct phy_device *phydev,
+		   u8 reg_num, u16 offset, u16 len, u16 data)
+{
+	u16 reg, mask;
+
+	if ((len + offset) >= 16)
+		mask = 0 - (1 << offset);
+	else
+		mask = (1 << (len + offset)) - (1 << offset);
+
+	reg = phy_read(phydev, MDIO_DEVAD_NONE, reg_num);
+
+	reg &= ~mask;
+	reg |= data << offset;
+
+	phy_write(phydev, MDIO_DEVAD_NONE, reg_num, reg);
+}
+
+static int m88e1518_config(struct phy_device *phydev)
+{
+	/*
+	 * As per Marvell Release Notes - Alaska 88E1510/88E1518/88E1512
+	 * /88E1514 Rev A0, Errata Section 3.1
+	 */
+	if (phydev->interface == PHY_INTERFACE_MODE_SGMII) {
+		phy_write(phydev, MDIO_DEVAD_NONE, 22, 0x00ff);	/* page 0xff */
+		phy_write(phydev, MDIO_DEVAD_NONE, 17, 0x214B);
+		phy_write(phydev, MDIO_DEVAD_NONE, 16, 0x2144);
+		phy_write(phydev, MDIO_DEVAD_NONE, 17, 0x0C28);
+		phy_write(phydev, MDIO_DEVAD_NONE, 16, 0x2146);
+		phy_write(phydev, MDIO_DEVAD_NONE, 17, 0xB233);
+		phy_write(phydev, MDIO_DEVAD_NONE, 16, 0x214D);
+		phy_write(phydev, MDIO_DEVAD_NONE, 17, 0xCC0C);
+		phy_write(phydev, MDIO_DEVAD_NONE, 16, 0x2159);
+		phy_write(phydev, MDIO_DEVAD_NONE, 22, 0x0000);	/* reg page 0 */
+		phy_write(phydev, MDIO_DEVAD_NONE, 22, 18);    /* reg page 18 */
+		/* Write HWCFG_MODE = SGMII to Copper */
+		m88e1518_phy_writebits(phydev, 20, 0, 3, 1);
+
+		/* Phy reset */
+		m88e1518_phy_writebits(phydev, 20, 15, 1, 1);
+		phy_write(phydev, MDIO_DEVAD_NONE, 22, 0);     /* reg page 18 */
+		udelay(100);
+	}
+
+	return m88e1111s_config(phydev);
+}
+
 /* Marvell 88E1118 */
 static int m88e1118_config(struct phy_device *phydev)
 {
@@ -493,7 +544,7 @@ static struct phy_driver M88E1518_driver = {
 	.uid = 0x1410dd1,
 	.mask = 0xffffff0,
 	.features = PHY_GBIT_FEATURES,
-	.config = &m88e1111s_config,
+	.config = &m88e1518_config,
 	.startup = &m88e1011s_startup,
 	.shutdown = &genphy_shutdown,
 };