net: bcmgenet: power up and down integrated GPHY when unused

Power up the GPHY while we are bringing-up the network interface, and
conversely, upon bring down, power the GPHY down. In order to avoid
creating hardware hazards, make sure that the GPHY gets powered on
during bcmgenet_open() prior to the UniMAC being reset as the UniMAC may
start creating activity towards the GPHY if we reverse the steps.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -869,6 +869,8 @@ static int bcmgenet_power_down(struct bcmgenet_priv *priv,
 			reg |= (EXT_PWR_DOWN_PHY |
 				EXT_PWR_DOWN_DLL | EXT_PWR_DOWN_BIAS);
 			bcmgenet_ext_writel(priv, reg, EXT_EXT_PWR_MGMT);
+
+			bcmgenet_phy_power_set(priv->dev, false);
 		}
 		break;
 	default:
@@ -2465,9 +2467,6 @@ static void bcmgenet_netif_start(struct net_device *dev)
 
 	umac_enable_set(priv, CMD_TX_EN | CMD_RX_EN, true);
 
-	if (phy_is_internal(priv->phydev))
-		bcmgenet_power_up(priv, GENET_POWER_PASSIVE);
-
 	netif_tx_start_all_queues(dev);
 
 	phy_start(priv->phydev);
@@ -2486,6 +2485,12 @@ static int bcmgenet_open(struct net_device *dev)
 	if (!IS_ERR(priv->clk))
 		clk_prepare_enable(priv->clk);
 
+	/* If this is an internal GPHY, power it back on now, before UniMAC is
+	 * brought out of reset as absolutely no UniMAC activity is allowed
+	 */
+	if (phy_is_internal(priv->phydev))
+		bcmgenet_power_up(priv, GENET_POWER_PASSIVE);
+
 	/* take MAC out of reset */
 	bcmgenet_umac_reset(priv);
 

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

@@ -664,6 +664,7 @@ int bcmgenet_mii_init(struct net_device *dev);
 int bcmgenet_mii_config(struct net_device *dev, bool init);
 void bcmgenet_mii_exit(struct net_device *dev);
 void bcmgenet_mii_reset(struct net_device *dev);
+void bcmgenet_phy_power_set(struct net_device *dev, bool enable);
 void bcmgenet_mii_setup(struct net_device *dev);
 
 /* Wake-on-LAN routines */

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

@@ -168,7 +168,7 @@ void bcmgenet_mii_reset(struct net_device *dev)
 	}
 }
 
-static void bcmgenet_phy_power_set(struct net_device *dev, bool enable)
+void bcmgenet_phy_power_set(struct net_device *dev, bool enable)
 {
 	struct bcmgenet_priv *priv = netdev_priv(dev);
 	u32 reg = 0;