The hardware classifies untagged and priority-tagged frames to the
port's PVID before the VLAN table lookup, and the FDB lookup key equals
the classified VID (measured on YT9215S).

The driver assigned PVID 4095 to the VLAN-unaware ports, while switchdev
reports the bridge's FDB entries with VID 0. These entries were then
installed under FID 0 and could never be hit by the hardware lookups.
Dynamic entries learnt under VID 4095, if any, took effect instead.

Lift the restriction on VLAN 0, and use it as the PVID of the
VLAN-unaware ports instead. The standalone default of 4095 stays, so
mislearnt entries, if any, would not pollute the bridge FDB.

Fixes: 186623f4aa72 ("net: dsa: yt921x: Add support for Motorcomm YT921x")
Signed-off-by: David Yang <mmyangfl@gmail.com>
---
 drivers/net/dsa/motorcomm/chip.c | 18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/drivers/net/dsa/motorcomm/chip.c b/drivers/net/dsa/motorcomm/chip.c
index a2be819ccbed..376f16466cdd 100644
--- a/drivers/net/dsa/motorcomm/chip.c
+++ b/drivers/net/dsa/motorcomm/chip.c
@@ -79,7 +79,6 @@ static const struct yt921x_info yt921x_infos[] = {
 	{}
 };
 
-#define YT921X_VID_UNWARE	4095
 
 struct yt921x_reg_mdio {
 	struct mii_bus *bus;
@@ -962,7 +961,7 @@ yt921x_vlan_filtering(struct yt921x_priv *priv, int port, bool vlan_filtering)
 	bdev = dsa_port_bridge_dev_get(dp);
 
 	if (!bdev || !vlan_filtering)
-		pvid = YT921X_VID_UNWARE;
+		pvid = 0;
 	else
 		br_vlan_get_pvid(bdev, &pvid);
 	res = yt921x_port_set_pvid(priv, port, pvid);
@@ -1030,8 +1029,7 @@ yt921x_pvid_clear(struct yt921x_priv *priv, int port)
 
 	vlan_filtering = dsa_port_is_vlan_filtering(dp);
 
-	res = yt921x_port_set_pvid(priv, port,
-				   vlan_filtering ? 0 : YT921X_VID_UNWARE);
+	res = yt921x_port_set_pvid(priv, port, 0);
 	if (res)
 		return res;
 
@@ -1188,7 +1186,7 @@ static int yt921x_userport_standalone(struct yt921x_priv *priv, int port)
 	/* Unrelated since learning is off and all packets are trapped;
 	 * set it anyway
 	 */
-	res = yt921x_port_set_pvid(priv, port, YT921X_VID_UNWARE);
+	res = yt921x_port_set_pvid(priv, port, 4095);
 	if (res)
 		return res;
 
@@ -2270,7 +2268,6 @@ static int yt921x_chip_setup_dsa(struct yt921x_priv *priv)
 {
 	struct dsa_switch *ds = &priv->ds;
 	unsigned long cpu_ports_mask;
-	u32 ctrls[2];
 	u32 ctrl;
 	int port;
 	int res;
@@ -2328,15 +2325,6 @@ static int yt921x_chip_setup_dsa(struct yt921x_priv *priv)
 	if (res)
 		return res;
 
-	/* Tagged VID 0 should be treated as untagged, which confuses the
-	 * hardware a lot
-	 */
-	ctrls[0] = YT921X_VLAN_CTRLa_LEARN_DIS | YT921X_VLAN_CTRLa_PORTS_M;
-	ctrls[1] = 0;
-	res = yt921x_reg64_write(priv, YT921X_VLANn_CTRL(0), ctrls);
-	if (res)
-		return res;
-
 	return 0;
 }
 
-- 
2.53.0