net: dsa: loop: Wire-up MTU callbacks

For now we simply store the port MTU into a per-port member.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/dsa_loop.c

@@ -225,6 +225,21 @@ static int dsa_loop_port_vlan_del(struct dsa_switch *ds, int port,
 	return 0;
 }
 
+static int dsa_loop_port_change_mtu(struct dsa_switch *ds, int port,
+				    int new_mtu)
+{
+	struct dsa_loop_priv *priv = ds->priv;
+
+	priv->ports[port].mtu = new_mtu;
+
+	return 0;
+}
+
+static int dsa_loop_port_max_mtu(struct dsa_switch *ds, int port)
+{
+	return ETH_MAX_MTU;
+}
+
 static const struct dsa_switch_ops dsa_loop_driver = {
 	.get_tag_protocol	= dsa_loop_get_protocol,
 	.setup			= dsa_loop_setup,
@@ -241,6 +256,8 @@ static const struct dsa_switch_ops dsa_loop_driver = {
 	.port_vlan_prepare	= dsa_loop_port_vlan_prepare,
 	.port_vlan_add		= dsa_loop_port_vlan_add,
 	.port_vlan_del		= dsa_loop_port_vlan_del,
+	.port_change_mtu	= dsa_loop_port_change_mtu,
+	.port_max_mtu		= dsa_loop_port_max_mtu,
 };
 
 static int dsa_loop_drv_probe(struct mdio_device *mdiodev)

include/linux/dsa/loop.h

@@ -27,6 +27,7 @@ enum dsa_loop_mib_counters {
 struct dsa_loop_port {
 	struct dsa_loop_mib_entry mib[__DSA_LOOP_CNT_MAX];
 	u16 pvid;
+	int mtu;
 };
 
 struct dsa_loop_priv {