rocker: Handle protodown notifications.

protodown can be set by user space applications like MLAG on detecting
errors on a switch port. This patch provides sample switch driver changes
for handling protodown. Rocker PHYS disables the port in response to
protodown.
Signed-off-by: NAnuradha Karuppiah <anuradhak@cumulusnetworks.com>
Signed-off-by: NAndy Gospodarek <gospo@cumulusnetworks.com>
Signed-off-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NWilson Kok <wkok@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/rocker/rocker.c

@@ -4015,7 +4015,8 @@ static int rocker_port_open(struct net_device *dev)
 
 	napi_enable(&rocker_port->napi_tx);
 	napi_enable(&rocker_port->napi_rx);
-	rocker_port_set_enable(rocker_port, true);
+	if (!dev->proto_down)
+		rocker_port_set_enable(rocker_port, true);
 	netif_start_queue(dev);
 	return 0;
 
@@ -4227,6 +4228,17 @@ static int rocker_port_get_phys_port_name(struct net_device *dev,
 	return err ? -EOPNOTSUPP : 0;
 }
 
+static int rocker_port_change_proto_down(struct net_device *dev,
+					 bool proto_down)
+{
+	struct rocker_port *rocker_port = netdev_priv(dev);
+
+	if (rocker_port->dev->flags & IFF_UP)
+		rocker_port_set_enable(rocker_port, !proto_down);
+	rocker_port->dev->proto_down = proto_down;
+	return 0;
+}
+
 static const struct net_device_ops rocker_port_netdev_ops = {
 	.ndo_open			= rocker_port_open,
 	.ndo_stop			= rocker_port_stop,
@@ -4240,6 +4252,7 @@ static const struct net_device_ops rocker_port_netdev_ops = {
 	.ndo_fdb_del			= switchdev_port_fdb_del,
 	.ndo_fdb_dump			= switchdev_port_fdb_dump,
 	.ndo_get_phys_port_name		= rocker_port_get_phys_port_name,
+	.ndo_change_proto_down		= rocker_port_change_proto_down,
 };
 
 /********************