net: bcmgenet: reset 40nm EPHY on energy detect

The EPHY integrated into the 40nm Set-Top Box devices can falsely
detect energy when connected to a disabled peer interface. When the
peer interface is enabled the EPHY will detect and report the link
as active, but on occasion may get into a state where it is not
able to exchange data with the connected GENET MAC. This issue has
not been observed when the link parameters are auto-negotiated;
however, it has been observed with a manually configured link.

It has been empirically determined that issuing a soft reset to the
EPHY when energy is detected prevents it from getting into this bad
state.

Fixes: 1c1008c7 ("net: bcmgenet: add main driver file")
Signed-off-by: Doug Berger <opendmb@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

@@ -2018,6 +2018,8 @@ static void bcmgenet_link_intr_enable(struct bcmgenet_priv *priv)
 	 */
 	if (priv->internal_phy) {
 		int0_enable |= UMAC_IRQ_LINK_EVENT;
+		if (GENET_IS_V1(priv) || GENET_IS_V2(priv) || GENET_IS_V3(priv))
+			int0_enable |= UMAC_IRQ_PHY_DET_R;
 	} else if (priv->ext_phy) {
 		int0_enable |= UMAC_IRQ_LINK_EVENT;
 	} else if (priv->phy_interface == PHY_INTERFACE_MODE_MOCA) {
@@ -2611,9 +2613,14 @@ static void bcmgenet_irq_task(struct work_struct *work)
 	priv->irq0_stat = 0;
 	spin_unlock_irq(&priv->lock);
 
+	if (status & UMAC_IRQ_PHY_DET_R &&
+	    priv->dev->phydev->autoneg != AUTONEG_ENABLE)
+		phy_init_hw(priv->dev->phydev);
+
 	/* Link UP/DOWN event */
 	if (status & UMAC_IRQ_LINK_EVENT)
 		phy_mac_interrupt(priv->dev->phydev);
+
 }
 
 /* bcmgenet_isr1: handle Rx and Tx priority queues */
@@ -2708,7 +2715,7 @@ static irqreturn_t bcmgenet_isr0(int irq, void *dev_id)
 	}
 
 	/* all other interested interrupts handled in bottom half */
-	status &= UMAC_IRQ_LINK_EVENT;
+	status &= (UMAC_IRQ_LINK_EVENT | UMAC_IRQ_PHY_DET_R);
 	if (status) {
 		/* Save irq status for bottom-half processing. */
 		spin_lock_irqsave(&priv->lock, flags);