[PATCH net-next 4/6] net: dsa: motorcomm: Translate FDB VID for VLAN-unaware bridges

[David Yang <mmyangfl@gmail.com>]

A VLAN-unaware bridge reports VID 0 for its FDB entries, but lookups run
with the unaware FID (VID 4095). Entries added through switchdev were
installed under FID 0 and could never be hit by the hardware lookups.

Translate the unaware FID and VID 0 back and forth, so the software
mapping stays symmetric with the hardware lookups.

Signed-off-by: David Yang <mmyangfl@gmail.com>
---
 drivers/net/dsa/motorcomm/chip.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/net/dsa/motorcomm/chip.c b/drivers/net/dsa/motorcomm/chip.c
index 907f7a5b0687..447736854870 100644
--- a/drivers/net/dsa/motorcomm/chip.c
+++ b/drivers/net/dsa/motorcomm/chip.c
@@ -590,6 +590,9 @@ yt921x_fdb_dump(struct yt921x_priv *priv, u16 ports_mask,
 	res = yt921x_fdb_read(priv, addr, &vid, &pmask, &index, &status);
 	if (res)
 		return res;
+
+	if (vid == YT921X_VID_UNWARE)
+		vid = 0;
 	if ((pmask & ports_mask) && !is_multicast_ether_addr(addr)) {
 		res = cb(addr, vid,
 			 status == YT921X_FDB_ENTRY_STATUS_STATIC, data);
@@ -618,6 +621,8 @@ yt921x_fdb_dump(struct yt921x_priv *priv, u16 ports_mask,
 		if (!pmask)
 			break;
 
+		if (vid == YT921X_VID_UNWARE)
+			vid = 0;
 		if ((pmask & ports_mask) && !is_multicast_ether_addr(addr)) {
 			res = cb(addr, vid,
 				 status == YT921X_FDB_ENTRY_STATUS_STATIC,
@@ -740,6 +745,10 @@ yt921x_fdb_leave(struct yt921x_priv *priv, const unsigned char *addr,
 	u32 val;
 	int res;
 
+	/* See yt921x_fdb_join() */
+	if (!vid)
+		vid = YT921X_VID_UNWARE;
+
 	/* Check for presence */
 	res = yt921x_fdb_has(priv, addr, vid, &index);
 	if (res)
@@ -782,6 +791,13 @@ yt921x_fdb_join(struct yt921x_priv *priv, const unsigned char *addr, u16 vid,
 	u32 val2;
 	int res;
 
+	/* A vlan-unaware bridge reports vid 0, but untagged lookups on its
+	 * ports run with the unaware FID; map so that static entries match the
+	 * hardware lookups.
+	 */
+	if (!vid)
+		vid = YT921X_VID_UNWARE;
+
 	/* Check for presence */
 	res = yt921x_fdb_has(priv, addr, vid, &index);
 	if (res)
-- 
2.53.0