net: dsa: sja1105: manage VLANs on cascade ports

Since commit ed040abc ("net: dsa: sja1105: use 4095 as the private
VLAN for untagged traffic"), this driver uses a reserved value as pvid
for the host port (DSA CPU port). Control packets which are sent as
untagged get classified to this VLAN, and all ports are members of it
(this is to be expected for control packets).

Manage all cascade ports in the same way and allow control packets to
egress everywhere.

Also, all VLANs need to be sent as egress-tagged on all cascade ports.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/sja1105/sja1105_main.c

@@ -460,7 +460,7 @@ static int sja1105_init_static_vlan(struct sja1105_private *priv)
 		pvid.vlan_bc |= BIT(port);
 		pvid.tag_port &= ~BIT(port);
 
-		if (dsa_is_cpu_port(ds, port)) {
+		if (dsa_is_cpu_port(ds, port) || dsa_is_dsa_port(ds, port)) {
 			priv->tag_8021q_pvid[port] = SJA1105_DEFAULT_VLAN;
 			priv->bridge_pvid[port] = SJA1105_DEFAULT_VLAN;
 		}
@@ -2310,8 +2310,8 @@ static int sja1105_bridge_vlan_add(struct dsa_switch *ds, int port,
 		return -EBUSY;
 	}
 
-	/* Always install bridge VLANs as egress-tagged on the CPU port. */
-	if (dsa_is_cpu_port(ds, port))
+	/* Always install bridge VLANs as egress-tagged on CPU and DSA ports */
+	if (dsa_is_cpu_port(ds, port) || dsa_is_dsa_port(ds, port))
 		flags = 0;
 
 	rc = sja1105_vlan_add(priv, port, vlan->vid, flags);