net: bcmgenet: improve bcmgenet_mii_setup()

bcmgenet_mii_setup() is called from the PHY state machine every 1-2 seconds
when the PHYs are in PHY_POLL mode.

Improve bcmgenet_mii_setup() so that it touches the MAC registers only when
the link is up and there was a change to link, speed, duplex, or pause status.

Signed-off-by: Petri Gynther <pgynther@google.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/genet/bcmgenet.c

@@ -2162,9 +2162,10 @@ static void bcmgenet_netif_stop(struct net_device *dev)
 	 */
 	cancel_work_sync(&priv->bcmgenet_irq_work);
 
-	priv->old_pause = -1;
 	priv->old_link = -1;
+	priv->old_speed = -1;
 	priv->old_duplex = -1;
+	priv->old_pause = -1;
 }
 
 static int bcmgenet_close(struct net_device *dev)

drivers/net/ethernet/broadcom/genet/bcmgenet.h

@@ -548,8 +548,9 @@ struct bcmgenet_priv {
 	u16 gphy_rev;
 
 	/* PHY device variables */
-	int old_duplex;
 	int old_link;
+	int old_speed;
+	int old_duplex;
 	int old_pause;
 	phy_interface_t phy_interface;
 	int phy_addr;

drivers/net/ethernet/broadcom/genet/bcmmii.c

@@ -82,24 +82,33 @@ static void bcmgenet_mii_setup(struct net_device *dev)
 	struct bcmgenet_priv *priv = netdev_priv(dev);
 	struct phy_device *phydev = priv->phydev;
 	u32 reg, cmd_bits = 0;
-	unsigned int status_changed = 0;
+	bool status_changed = false;
 
 	if (priv->old_link != phydev->link) {
-		status_changed = 1;
+		status_changed = true;
 		priv->old_link = phydev->link;
 	}
 
 	if (phydev->link) {
-		/* program UMAC and RGMII block based on established link
-		 * speed, pause, and duplex.
-		 * the speed set in umac->cmd tell RGMII block which clock
-		 * 25MHz(100Mbps)/125MHz(1Gbps) to use for transmit.
-		 * receive clock is provided by PHY.
-		 */
-		reg = bcmgenet_ext_readl(priv, EXT_RGMII_OOB_CTRL);
-		reg &= ~OOB_DISABLE;
-		reg |= RGMII_LINK;
-		bcmgenet_ext_writel(priv, reg, EXT_RGMII_OOB_CTRL);
+		/* check speed/duplex/pause changes */
+		if (priv->old_speed != phydev->speed) {
+			status_changed = true;
+			priv->old_speed = phydev->speed;
+		}
+
+		if (priv->old_duplex != phydev->duplex) {
+			status_changed = true;
+			priv->old_duplex = phydev->duplex;
+		}
+
+		if (priv->old_pause != phydev->pause) {
+			status_changed = true;
+			priv->old_pause = phydev->pause;
+		}
+
+		/* done if nothing has changed */
+		if (!status_changed)
+			return;
 
 		/* speed */
 		if (phydev->speed == SPEED_1000)
@@ -110,36 +119,39 @@ static void bcmgenet_mii_setup(struct net_device *dev)
 			cmd_bits = UMAC_SPEED_10;
 		cmd_bits <<= CMD_SPEED_SHIFT;
 
-		if (priv->old_duplex != phydev->duplex) {
-			status_changed = 1;
-			priv->old_duplex = phydev->duplex;
-		}
-
 		/* duplex */
 		if (phydev->duplex != DUPLEX_FULL)
 			cmd_bits |= CMD_HD_EN;
 
-		if (priv->old_pause != phydev->pause) {
-			status_changed = 1;
-			priv->old_pause = phydev->pause;
-		}
-
 		/* pause capability */
 		if (!phydev->pause)
 			cmd_bits |= CMD_RX_PAUSE_IGNORE | CMD_TX_PAUSE_IGNORE;
-	}
 
-	if (!status_changed)
-		return;
+		/*
+		 * Program UMAC and RGMII block based on established
+		 * link speed, duplex, and pause. The speed set in
+		 * umac->cmd tell RGMII block which clock to use for
+		 * transmit -- 25MHz(100Mbps) or 125MHz(1Gbps).
+		 * Receive clock is provided by the PHY.
+		 */
+		reg = bcmgenet_ext_readl(priv, EXT_RGMII_OOB_CTRL);
+		reg &= ~OOB_DISABLE;
+		reg |= RGMII_LINK;
+		bcmgenet_ext_writel(priv, reg, EXT_RGMII_OOB_CTRL);
 
-	if (phydev->link) {
 		reg = bcmgenet_umac_readl(priv, UMAC_CMD);
 		reg &= ~((CMD_SPEED_MASK << CMD_SPEED_SHIFT) |
 			       CMD_HD_EN |
 			       CMD_RX_PAUSE_IGNORE | CMD_TX_PAUSE_IGNORE);
 		reg |= cmd_bits;
 		bcmgenet_umac_writel(priv, reg, UMAC_CMD);
+	} else {
+		/* done if nothing has changed */
+		if (!status_changed)
+			return;
 
+		/* needed for MoCA fixed PHY to reflect correct link status */
+		netif_carrier_off(dev);
 	}
 
 	phy_print_status(phydev);
@@ -318,16 +330,19 @@ static int bcmgenet_mii_probe(struct net_device *dev)
 	/* Communicate the integrated PHY revision */
 	phy_flags = priv->gphy_rev;
 
+	/* Initialize link state variables that bcmgenet_mii_setup() uses */
+	priv->old_link = -1;
+	priv->old_speed = -1;
+	priv->old_duplex = -1;
+	priv->old_pause = -1;
+
 	phydev = of_phy_connect(dev, priv->phy_dn, bcmgenet_mii_setup,
 				phy_flags, priv->phy_interface);
 	if (!phydev) {
 		pr_err("could not attach to PHY\n");
 		return -ENODEV;
 	}
 
-	priv->old_link = -1;
-	priv->old_duplex = -1;
-	priv->old_pause = -1;
 	priv->phydev = phydev;
 
 	/* Configure port multiplexer based on what the probed PHY device since