net: dsa: add port enable and disable helpers

Provide dsa_port_enable and dsa_port_disable helpers to respectively
enable and disable a switch port. This makes the dsa_port_set_state_now
helper static.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dsa/port.c b/net/dsa/port.c
index 76d43a8..72c8dbd3 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -56,7 +56,7 @@
 	return 0;
 }
 
-void dsa_port_set_state_now(struct dsa_port *dp, u8 state)
+static void dsa_port_set_state_now(struct dsa_port *dp, u8 state)
 {
 	int err;
 
@@ -65,6 +65,35 @@
 		pr_err("DSA: failed to set STP state %u (%d)\n", state, err);
 }
 
+int dsa_port_enable(struct dsa_port *dp, struct phy_device *phy)
+{
+	u8 stp_state = dp->bridge_dev ? BR_STATE_BLOCKING : BR_STATE_FORWARDING;
+	struct dsa_switch *ds = dp->ds;
+	int port = dp->index;
+	int err;
+
+	if (ds->ops->port_enable) {
+		err = ds->ops->port_enable(ds, port, phy);
+		if (err)
+			return err;
+	}
+
+	dsa_port_set_state_now(dp, stp_state);
+
+	return 0;
+}
+
+void dsa_port_disable(struct dsa_port *dp, struct phy_device *phy)
+{
+	struct dsa_switch *ds = dp->ds;
+	int port = dp->index;
+
+	dsa_port_set_state_now(dp, BR_STATE_DISABLED);
+
+	if (ds->ops->port_disable)
+		ds->ops->port_disable(ds, port, phy);
+}
+
 int dsa_port_bridge_join(struct dsa_port *dp, struct net_device *br)
 {
 	struct dsa_notifier_bridge_info info = {