[RFC PATCH net-next 1/8] net: dsa: felix: program host FDB entries towards PGID_CPU for tag_8021q too

[Vladimir Oltean <vladimir.oltean@nxp.com>]

I remembered why we had the host FDB migration procedure in place.

It is true that host FDB entry migration can be done by changing the
value of PGID_CPU, but the problem is that only host FDB entries learned
while operating in NPI mode go to PGID_CPU. When the CPU port operates
in tag_8021q mode, the FDB entries are learned towards the unicast PGID
equal to the physical port number of this CPU port, bypassing the
PGID_CPU indirection.

So host FDB entries learned in tag_8021q mode are not migrated any
longer towards the NPI port.

Fix this by extracting the NPI port -> PGID_CPU redirection from the
ocelot switch lib, moving it to the Felix DSA driver, and applying it
for any CPU port regardless of its kind (NPI or tag_8021q).

Fixes: 51349ba7f2f0 ("net: dsa: felix: stop migrating FDBs back and forth on tag proto change")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 drivers/net/dsa/ocelot/felix.c     | 12 ++++++++++--
 drivers/net/ethernet/mscc/ocelot.c |  7 +------
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/net/dsa/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c
index e30fdde8d189..d0105a11bc4f 100644
--- a/drivers/net/dsa/ocelot/felix.c
+++ b/drivers/net/dsa/ocelot/felix.c
@@ -668,15 +668,19 @@ static int felix_fdb_add(struct dsa_switch *ds, int port,
 			 struct dsa_db db)
 {
 	struct net_device *bridge_dev = felix_classify_db(db);
+	struct dsa_port *dp = dsa_to_port(ds, port);
 	struct ocelot *ocelot = ds->priv;
 
 	if (IS_ERR(bridge_dev))
 		return PTR_ERR(bridge_dev);
 
-	if (dsa_is_cpu_port(ds, port) && !bridge_dev &&
+	if (dsa_port_is_cpu(dp) && !bridge_dev &&
 	    dsa_fdb_present_in_other_db(ds, port, addr, vid, db))
 		return 0;
 
+	if (dsa_port_is_cpu(dp))
+		port = PGID_CPU;
+
 	return ocelot_fdb_add(ocelot, port, addr, vid, bridge_dev);
 }
 
@@ -685,15 +689,19 @@ static int felix_fdb_del(struct dsa_switch *ds, int port,
 			 struct dsa_db db)
 {
 	struct net_device *bridge_dev = felix_classify_db(db);
+	struct dsa_port *dp = dsa_to_port(ds, port);
 	struct ocelot *ocelot = ds->priv;
 
 	if (IS_ERR(bridge_dev))
 		return PTR_ERR(bridge_dev);
 
-	if (dsa_is_cpu_port(ds, port) && !bridge_dev &&
+	if (dsa_port_is_cpu(dp) && !bridge_dev &&
 	    dsa_fdb_present_in_other_db(ds, port, addr, vid, db))
 		return 0;
 
+	if (dsa_port_is_cpu(dp))
+		port = PGID_CPU;
+
 	return ocelot_fdb_del(ocelot, port, addr, vid, bridge_dev);
 }
 
diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index 5f81938c58a9..7a9ee91c8427 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -1349,15 +1349,10 @@ EXPORT_SYMBOL(ocelot_drain_cpu_queue);
 int ocelot_fdb_add(struct ocelot *ocelot, int port, const unsigned char *addr,
 		   u16 vid, const struct net_device *bridge)
 {
-	int pgid = port;
-
-	if (port == ocelot->npi)
-		pgid = PGID_CPU;
-
 	if (!vid)
 		vid = ocelot_vlan_unaware_pvid(ocelot, bridge);
 
-	return ocelot_mact_learn(ocelot, pgid, addr, vid, ENTRYTYPE_LOCKED);
+	return ocelot_mact_learn(ocelot, port, addr, vid, ENTRYTYPE_LOCKED);
 }
 EXPORT_SYMBOL(ocelot_fdb_add);
 
-- 
2.25.1