net: stmmac: enable clause 45 mdio support

DWMAC4 is capable to support clause 45 mdio communication.
This patch enable the feature on stmmac_mdio_write() and
stmmac_mdio_read() by following phy_write_mmd() and
phy_read_mmd() mdiobus read write implementation format.

Reviewed-by: Li, Yifan <yifan2.li@intel.com>
Signed-off-by: Kweh Hock Leong <hock.leong.kweh@intel.com>
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: Voon Weifeng <weifeng.voon@intel.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c

@@ -24,11 +24,14 @@
 
 #define MII_BUSY 0x00000001
 #define MII_WRITE 0x00000002
+#define MII_DATA_MASK GENMASK(15, 0)
 
 /* GMAC4 defines */
 #define MII_GMAC4_GOC_SHIFT		2
+#define MII_GMAC4_REG_ADDR_SHIFT	16
 #define MII_GMAC4_WRITE			(1 << MII_GMAC4_GOC_SHIFT)
 #define MII_GMAC4_READ			(3 << MII_GMAC4_GOC_SHIFT)
+#define MII_GMAC4_C45E			BIT(1)
 
 /* XGMAC defines */
 #define MII_XGMAC_SADDR			BIT(18)
@@ -155,30 +158,42 @@ static int stmmac_mdio_read(struct mii_bus *bus, int phyaddr, int phyreg)
 	struct stmmac_priv *priv = netdev_priv(ndev);
 	unsigned int mii_address = priv->hw->mii.addr;
 	unsigned int mii_data = priv->hw->mii.data;
-	u32 v;
-	int data;
 	u32 value = MII_BUSY;
+	int data = 0;
+	u32 v;
 
 	value |= (phyaddr << priv->hw->mii.addr_shift)
 		& priv->hw->mii.addr_mask;
 	value |= (phyreg << priv->hw->mii.reg_shift) & priv->hw->mii.reg_mask;
 	value |= (priv->clk_csr << priv->hw->mii.clk_csr_shift)
 		& priv->hw->mii.clk_csr_mask;
-	if (priv->plat->has_gmac4)
+	if (priv->plat->has_gmac4) {
 		value |= MII_GMAC4_READ;
+		if (phyreg & MII_ADDR_C45) {
+			value |= MII_GMAC4_C45E;
+			value &= ~priv->hw->mii.reg_mask;
+			value |= ((phyreg >> MII_DEVADDR_C45_SHIFT) <<
+			       priv->hw->mii.reg_shift) &
+			       priv->hw->mii.reg_mask;
+
+			data |= (phyreg & MII_REGADDR_C45_MASK) <<
+				MII_GMAC4_REG_ADDR_SHIFT;
+		}
+	}
 
 	if (readl_poll_timeout(priv->ioaddr + mii_address, v, !(v & MII_BUSY),
 			       100, 10000))
 		return -EBUSY;
 
+	writel(data, priv->ioaddr + mii_data);
 	writel(value, priv->ioaddr + mii_address);
 
 	if (readl_poll_timeout(priv->ioaddr + mii_address, v, !(v & MII_BUSY),
 			       100, 10000))
 		return -EBUSY;
 
 	/* Read the data from the MII data register */
-	data = (int)readl(priv->ioaddr + mii_data);
+	data = (int)readl(priv->ioaddr + mii_data) & MII_DATA_MASK;
 
 	return data;
 }
@@ -198,27 +213,39 @@ static int stmmac_mdio_write(struct mii_bus *bus, int phyaddr, int phyreg,
 	struct stmmac_priv *priv = netdev_priv(ndev);
 	unsigned int mii_address = priv->hw->mii.addr;
 	unsigned int mii_data = priv->hw->mii.data;
-	u32 v;
 	u32 value = MII_BUSY;
+	int data = phydata;
+	u32 v;
 
 	value |= (phyaddr << priv->hw->mii.addr_shift)
 		& priv->hw->mii.addr_mask;
 	value |= (phyreg << priv->hw->mii.reg_shift) & priv->hw->mii.reg_mask;
 
 	value |= (priv->clk_csr << priv->hw->mii.clk_csr_shift)
 		& priv->hw->mii.clk_csr_mask;
-	if (priv->plat->has_gmac4)
+	if (priv->plat->has_gmac4) {
 		value |= MII_GMAC4_WRITE;
-	else
+		if (phyreg & MII_ADDR_C45) {
+			value |= MII_GMAC4_C45E;
+			value &= ~priv->hw->mii.reg_mask;
+			value |= ((phyreg >> MII_DEVADDR_C45_SHIFT) <<
+			       priv->hw->mii.reg_shift) &
+			       priv->hw->mii.reg_mask;
+
+			data |= (phyreg & MII_REGADDR_C45_MASK) <<
+				MII_GMAC4_REG_ADDR_SHIFT;
+		}
+	} else {
 		value |= MII_WRITE;
+	}
 
 	/* Wait until any existing MII operation is complete */
 	if (readl_poll_timeout(priv->ioaddr + mii_address, v, !(v & MII_BUSY),
 			       100, 10000))
 		return -EBUSY;
 
 	/* Set the MII address register to write */
-	writel(phydata, priv->ioaddr + mii_data);
+	writel(data, priv->ioaddr + mii_data);
 	writel(value, priv->ioaddr + mii_address);
 
 	/* Wait until any existing MII operation is complete */

include/linux/phy.h

@@ -195,6 +195,8 @@ static inline const char *phy_modes(phy_interface_t interface)
 /* Or MII_ADDR_C45 into regnum for read/write on mii_bus to enable the 21 bit
    IEEE 802.3ae clause 45 addressing mode used by 10GIGE phy chips. */
 #define MII_ADDR_C45 (1<<30)
+#define MII_DEVADDR_C45_SHIFT	16
+#define MII_REGADDR_C45_MASK	GENMASK(15, 0)
 
 struct device;
 struct phylink;