net: dsa: b53: keep CPU port always tagged again

The Broadcom management header does not carry the original VLAN tag
state information, just the ingress port, so for untagged frames we do
not know from which VLAN they originated.

Therefore keep the CPU port always tagged except for VLAN 0.

Fixes the following setup:

$ ip link add br0 type bridge vlan_filtering 1
$ ip link set sw1p1 master br0
$ bridge vlan add dev br0 pvid untagged self
$ ip link add sw1p2.10 link sw1p2 type vlan id 10

Where VID 10 would stay untagged on the CPU port.

Fixes: 2c32a3d3c233 ("net: dsa: b53: Do not force CPU to be always tagged")
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Tested-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/20250429201710.330937-3-jonas.gorski@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
index 62866165ad03c332449cd47335c2663c605fe626..9d4fb54b4ced6b9d4dd0dbba6535c88ed80966a9 100644 (file)
--- a/drivers/net/dsa/b53/b53_common.c
+++ b/drivers/net/dsa/b53/b53_common.c
@@ -1135,6 +1135,11 @@ static int b53_setup(struct dsa_switch *ds)
         */
        ds->untag_bridge_pvid = dev->tag_protocol == DSA_TAG_PROTO_NONE;
 
+       /* The switch does not tell us the original VLAN for untagged
+        * packets, so keep the CPU port always tagged.
+        */
+       ds->untag_vlan_aware_bridge_pvid = true;
+
        ret = b53_reset_switch(dev);
        if (ret) {
                dev_err(ds->dev, "failed to reset switch\n");
@@ -1545,6 +1550,9 @@ int b53_vlan_add(struct dsa_switch *ds, int port,
        if (vlan->vid == 0 && vlan->vid == b53_default_pvid(dev))
                untagged = true;
 
+       if (vlan->vid > 0 && dsa_is_cpu_port(ds, port))
+               untagged = false;
+
        vl->members |= BIT(port);
        if (untagged && !b53_vlan_port_needs_forced_tagged(ds, port))
                vl->untag |= BIT(port);