net: dsa: qca8k: improve internal mdio read/write bus access

Improve the internal mdio read/write bus access by caching the value
without accessing it for every read/write.
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/qca8k.c

@@ -655,6 +655,7 @@ static int
 qca8k_mdio_write(struct mii_bus *salve_bus, int phy, int regnum, u16 data)
 {
 	struct qca8k_priv *priv = salve_bus->priv;
+	struct mii_bus *bus = priv->bus;
 	u16 r1, r2, page;
 	u32 val;
 	int ret;
@@ -669,22 +670,22 @@ qca8k_mdio_write(struct mii_bus *salve_bus, int phy, int regnum, u16 data)
 
 	qca8k_split_addr(QCA8K_MDIO_MASTER_CTRL, &r1, &r2, &page);
 
-	mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED);
+	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
 
-	ret = qca8k_set_page(priv->bus, page);
+	ret = qca8k_set_page(bus, page);
 	if (ret)
 		goto exit;
 
-	qca8k_mii_write32(priv->bus, 0x10 | r2, r1, val);
+	qca8k_mii_write32(bus, 0x10 | r2, r1, val);
 
-	ret = qca8k_mdio_busy_wait(priv->bus, QCA8K_MDIO_MASTER_CTRL,
+	ret = qca8k_mdio_busy_wait(bus, QCA8K_MDIO_MASTER_CTRL,
 				   QCA8K_MDIO_MASTER_BUSY);
 
 exit:
 	/* even if the busy_wait timeouts try to clear the MASTER_EN */
-	qca8k_mii_write32(priv->bus, 0x10 | r2, r1, 0);
+	qca8k_mii_write32(bus, 0x10 | r2, r1, 0);
 
-	mutex_unlock(&priv->bus->mdio_lock);
+	mutex_unlock(&bus->mdio_lock);
 
 	return ret;
 }
@@ -693,6 +694,7 @@ static int
 qca8k_mdio_read(struct mii_bus *salve_bus, int phy, int regnum)
 {
 	struct qca8k_priv *priv = salve_bus->priv;
+	struct mii_bus *bus = priv->bus;
 	u16 r1, r2, page;
 	u32 val;
 	int ret;
@@ -706,26 +708,26 @@ qca8k_mdio_read(struct mii_bus *salve_bus, int phy, int regnum)
 
 	qca8k_split_addr(QCA8K_MDIO_MASTER_CTRL, &r1, &r2, &page);
 
-	mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED);
+	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
 
-	ret = qca8k_set_page(priv->bus, page);
+	ret = qca8k_set_page(bus, page);
 	if (ret)
 		goto exit;
 
-	qca8k_mii_write32(priv->bus, 0x10 | r2, r1, val);
+	qca8k_mii_write32(bus, 0x10 | r2, r1, val);
 
-	ret = qca8k_mdio_busy_wait(priv->bus, QCA8K_MDIO_MASTER_CTRL,
+	ret = qca8k_mdio_busy_wait(bus, QCA8K_MDIO_MASTER_CTRL,
 				   QCA8K_MDIO_MASTER_BUSY);
 	if (ret)
 		goto exit;
 
-	val = qca8k_mii_read32(priv->bus, 0x10 | r2, r1);
+	val = qca8k_mii_read32(bus, 0x10 | r2, r1);
 
 exit:
 	/* even if the busy_wait timeouts try to clear the MASTER_EN */
-	qca8k_mii_write32(priv->bus, 0x10 | r2, r1, 0);
+	qca8k_mii_write32(bus, 0x10 | r2, r1, 0);
 
-	mutex_unlock(&priv->bus->mdio_lock);
+	mutex_unlock(&bus->mdio_lock);
 
 	if (val >= 0)
 		val &= QCA8K_MDIO_MASTER_DATA_MASK;