net: dsa: Implement ndo_get_phys_port_id

Implement ndo_get_phys_port_id() by returning the physical port number
of the switch this per-port DSA created network interface corresponds
to.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/slave.c

@@ -984,6 +984,17 @@ static void dsa_slave_poll_controller(struct net_device *dev)
 }
 #endif
 
+static int dsa_slave_get_phys_port_id(struct net_device *dev,
+				      struct netdev_phys_item_id *ppid)
+{
+	struct dsa_slave_priv *p = netdev_priv(dev);
+
+	ppid->id_len = sizeof(p->port);
+	memcpy(ppid->id, &p->port, ppid->id_len);
+
+	return 0;
+}
+
 void dsa_cpu_port_ethtool_init(struct ethtool_ops *ops)
 {
 	ops->get_sset_count = dsa_cpu_port_get_sset_count;
@@ -1031,6 +1042,7 @@ static const struct net_device_ops dsa_slave_netdev_ops = {
 	.ndo_bridge_getlink	= switchdev_port_bridge_getlink,
 	.ndo_bridge_setlink	= switchdev_port_bridge_setlink,
 	.ndo_bridge_dellink	= switchdev_port_bridge_dellink,
+	.ndo_get_phys_port_id	= dsa_slave_get_phys_port_id,
 };
 
 static const struct switchdev_ops dsa_slave_switchdev_ops = {