net: dsa: sja1105: add FDB fast ageing support

Delete the dynamically learned FDB entries when the STP state changes
and when address learning is disabled.

On sja1105 there is no shorthand SPI command for this, so we need to
walk through the entire FDB to delete.
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

@@ -1794,6 +1794,46 @@ static int sja1105_fdb_dump(struct dsa_switch *ds, int port,
 	return 0;
 }
 
+static void sja1105_fast_age(struct dsa_switch *ds, int port)
+{
+	struct sja1105_private *priv = ds->priv;
+	int i;
+
+	for (i = 0; i < SJA1105_MAX_L2_LOOKUP_COUNT; i++) {
+		struct sja1105_l2_lookup_entry l2_lookup = {0};
+		u8 macaddr[ETH_ALEN];
+		int rc;
+
+		rc = sja1105_dynamic_config_read(priv, BLK_IDX_L2_LOOKUP,
+						 i, &l2_lookup);
+		/* No fdb entry at i, not an issue */
+		if (rc == -ENOENT)
+			continue;
+		if (rc) {
+			dev_err(ds->dev, "Failed to read FDB: %pe\n",
+				ERR_PTR(rc));
+			return;
+		}
+
+		if (!(l2_lookup.destports & BIT(port)))
+			continue;
+
+		/* Don't delete static FDB entries */
+		if (l2_lookup.lockeds)
+			continue;
+
+		u64_to_ether_addr(l2_lookup.macaddr, macaddr);
+
+		rc = sja1105_fdb_del(ds, port, macaddr, l2_lookup.vlanid);
+		if (rc) {
+			dev_err(ds->dev,
+				"Failed to delete FDB entry %pM vid %lld: %pe\n",
+				macaddr, l2_lookup.vlanid, ERR_PTR(rc));
+			return;
+		}
+	}
+}
+
 static int sja1105_mdb_add(struct dsa_switch *ds, int port,
 			   const struct switchdev_obj_port_mdb *mdb)
 {
@@ -3036,6 +3076,7 @@ static const struct dsa_switch_ops sja1105_switch_ops = {
 	.port_fdb_dump		= sja1105_fdb_dump,
 	.port_fdb_add		= sja1105_fdb_add,
 	.port_fdb_del		= sja1105_fdb_del,
+	.port_fast_age		= sja1105_fast_age,
 	.port_bridge_join	= sja1105_bridge_join,
 	.port_bridge_leave	= sja1105_bridge_leave,
 	.port_pre_bridge_flags	= sja1105_port_pre_bridge_flags,