net: ethernet: mtk_eth_soc: implement Clause 45 MDIO access

Implement read and write access to IEEE 802.3 Clause 45 Ethernet
phy registers while making use of new mdiobus_c45_regad and
mdiobus_c45_devad helpers.

Tested on the Ubiquiti UniFi 6 LR access point featuring
MediaTek MT7622BV WiSoC with Aquantia AQR112C.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mediatek/mtk_eth_soc.c

@@ -103,13 +103,35 @@ static int _mtk_mdio_write(struct mtk_eth *eth, u32 phy_addr, u32 phy_reg,
 	if (ret < 0)
 		return ret;
 
-	mtk_w32(eth, PHY_IAC_ACCESS |
-		     PHY_IAC_START_C22 |
-		     PHY_IAC_CMD_WRITE |
-		     PHY_IAC_REG(phy_reg) |
-		     PHY_IAC_ADDR(phy_addr) |
-		     PHY_IAC_DATA(write_data),
-		MTK_PHY_IAC);
+	if (phy_reg & MII_ADDR_C45) {
+		mtk_w32(eth, PHY_IAC_ACCESS |
+			     PHY_IAC_START_C45 |
+			     PHY_IAC_CMD_C45_ADDR |
+			     PHY_IAC_REG(mdiobus_c45_devad(phy_reg)) |
+			     PHY_IAC_ADDR(phy_addr) |
+			     PHY_IAC_DATA(mdiobus_c45_regad(phy_reg)),
+			MTK_PHY_IAC);
+
+		ret = mtk_mdio_busy_wait(eth);
+		if (ret < 0)
+			return ret;
+
+		mtk_w32(eth, PHY_IAC_ACCESS |
+			     PHY_IAC_START_C45 |
+			     PHY_IAC_CMD_WRITE |
+			     PHY_IAC_REG(mdiobus_c45_devad(phy_reg)) |
+			     PHY_IAC_ADDR(phy_addr) |
+			     PHY_IAC_DATA(write_data),
+			MTK_PHY_IAC);
+	} else {
+		mtk_w32(eth, PHY_IAC_ACCESS |
+			     PHY_IAC_START_C22 |
+			     PHY_IAC_CMD_WRITE |
+			     PHY_IAC_REG(phy_reg) |
+			     PHY_IAC_ADDR(phy_addr) |
+			     PHY_IAC_DATA(write_data),
+			MTK_PHY_IAC);
+	}
 
 	ret = mtk_mdio_busy_wait(eth);
 	if (ret < 0)
@@ -126,12 +148,33 @@ static int _mtk_mdio_read(struct mtk_eth *eth, u32 phy_addr, u32 phy_reg)
 	if (ret < 0)
 		return ret;
 
-	mtk_w32(eth, PHY_IAC_ACCESS |
-		     PHY_IAC_START_C22 |
-		     PHY_IAC_CMD_C22_READ |
-		     PHY_IAC_REG(phy_reg) |
-		     PHY_IAC_ADDR(phy_addr),
-		MTK_PHY_IAC);
+	if (phy_reg & MII_ADDR_C45) {
+		mtk_w32(eth, PHY_IAC_ACCESS |
+			     PHY_IAC_START_C45 |
+			     PHY_IAC_CMD_C45_ADDR |
+			     PHY_IAC_REG(mdiobus_c45_devad(phy_reg)) |
+			     PHY_IAC_ADDR(phy_addr) |
+			     PHY_IAC_DATA(mdiobus_c45_regad(phy_reg)),
+			MTK_PHY_IAC);
+
+		ret = mtk_mdio_busy_wait(eth);
+		if (ret < 0)
+			return ret;
+
+		mtk_w32(eth, PHY_IAC_ACCESS |
+			     PHY_IAC_START_C45 |
+			     PHY_IAC_CMD_C45_READ |
+			     PHY_IAC_REG(mdiobus_c45_devad(phy_reg)) |
+			     PHY_IAC_ADDR(phy_addr),
+			MTK_PHY_IAC);
+	} else {
+		mtk_w32(eth, PHY_IAC_ACCESS |
+			     PHY_IAC_START_C22 |
+			     PHY_IAC_CMD_C22_READ |
+			     PHY_IAC_REG(phy_reg) |
+			     PHY_IAC_ADDR(phy_addr),
+			MTK_PHY_IAC);
+	}
 
 	ret = mtk_mdio_busy_wait(eth);
 	if (ret < 0)
@@ -504,6 +547,7 @@ static int mtk_mdio_init(struct mtk_eth *eth)
 	eth->mii_bus->name = "mdio";
 	eth->mii_bus->read = mtk_mdio_read;
 	eth->mii_bus->write = mtk_mdio_write;
+	eth->mii_bus->probe_capabilities = MDIOBUS_C22_C45;
 	eth->mii_bus->priv = eth;
 	eth->mii_bus->parent = eth->dev;
 

drivers/net/ethernet/mediatek/mtk_eth_soc.h

@@ -346,9 +346,12 @@
 #define PHY_IAC_ADDR_MASK	GENMASK(24, 20)
 #define PHY_IAC_ADDR(x)		FIELD_PREP(PHY_IAC_ADDR_MASK, (x))
 #define PHY_IAC_CMD_MASK	GENMASK(19, 18)
+#define PHY_IAC_CMD_C45_ADDR	FIELD_PREP(PHY_IAC_CMD_MASK, 0)
 #define PHY_IAC_CMD_WRITE	FIELD_PREP(PHY_IAC_CMD_MASK, 1)
 #define PHY_IAC_CMD_C22_READ	FIELD_PREP(PHY_IAC_CMD_MASK, 2)
+#define PHY_IAC_CMD_C45_READ	FIELD_PREP(PHY_IAC_CMD_MASK, 3)
 #define PHY_IAC_START_MASK	GENMASK(17, 16)
+#define PHY_IAC_START_C45	FIELD_PREP(PHY_IAC_START_MASK, 0)
 #define PHY_IAC_START_C22	FIELD_PREP(PHY_IAC_START_MASK, 1)
 #define PHY_IAC_DATA_MASK	GENMASK(15, 0)
 #define PHY_IAC_DATA(x)		FIELD_PREP(PHY_IAC_DATA_MASK, (x))