Merge branch 'lantiq_gswip-fixes'

Vladimir Oltean says:

====================
lantiq_gswip fixes

This is a small set of fixes which I believe should be backported for
the lantiq_gswip driver. Daniel Golle asked me to submit them here:
https://lore.kernel.org/netdev/aLiDfrXUbw1O5Vdi@pidgin.makrotopia.org/

As mentioned there, a merge conflict with net-next is expected, due to
the movement of the driver to the 'drivers/net/dsa/lantiq' folder there.
Good luck :-/

Patch 2/2 fixes an old regression and is the minimal fix for that, as
discussed here:
https://lore.kernel.org/netdev/aJfNMLNoi1VOsPrN@pidgin.makrotopia.org/

Patch 1/2 was identified by me through static analysis, and I consider
it to be a serious deficiency. It needs a test tag.
====================

Link: https://patch.msgid.link/20250918072142.894692-1-vladimir.oltean@nxp.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: Paolo Abeni

drivers/net/dsa/lantiq_gswip.c

@@ -685,18 +685,27 @@ static int gswip_add_single_port_br(struct gswip_priv *priv, int port, bool add)
 	return 0;
 }
 
-static int gswip_port_enable(struct dsa_switch *ds, int port,
-			     struct phy_device *phydev)
+static int gswip_port_setup(struct dsa_switch *ds, int port)
 {
 	struct gswip_priv *priv = ds->priv;
 	int err;
 
 	if (!dsa_is_cpu_port(ds, port)) {
-		u32 mdio_phy = 0;
-
 		err = gswip_add_single_port_br(priv, port, true);
 		if (err)
 			return err;
+	}
+
+	return 0;
+}
+
+static int gswip_port_enable(struct dsa_switch *ds, int port,
+			     struct phy_device *phydev)
+{
+	struct gswip_priv *priv = ds->priv;
+
+	if (!dsa_is_cpu_port(ds, port)) {
+		u32 mdio_phy = 0;
 
 		if (phydev)
 			mdio_phy = phydev->mdio.addr & GSWIP_MDIO_PHY_ADDR_MASK;
@@ -1359,8 +1368,9 @@ static int gswip_port_fdb(struct dsa_switch *ds, int port,
 	int i;
 	int err;
 
+	/* Operation not supported on the CPU port, don't throw errors */
 	if (!bridge)
-		return -EINVAL;
+		return 0;
 
 	for (i = max_ports; i < ARRAY_SIZE(priv->vlans); i++) {
 		if (priv->vlans[i].bridge == bridge) {
@@ -1829,6 +1839,7 @@ static const struct phylink_mac_ops gswip_phylink_mac_ops = {
 static const struct dsa_switch_ops gswip_xrx200_switch_ops = {
 	.get_tag_protocol	= gswip_get_tag_protocol,
 	.setup			= gswip_setup,
+	.port_setup		= gswip_port_setup,
 	.port_enable		= gswip_port_enable,
 	.port_disable		= gswip_port_disable,
 	.port_bridge_join	= gswip_port_bridge_join,