net: dsa: hellcreek: Report FDB table occupancy

Report the FDB table size and occupancy via devlink. The actual size depends on
the used Hellcreek version:

|root@tsn:~# devlink resource show platform/ff240000.switch
|platform/ff240000.switch:
|  name VLAN size 4096 occ 2 unit entry dpipe_tables none
|  name FDB size 256 occ 6 unit entry dpipe_tables none
Suggested-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NKurt Kanzenbach <kurt@kmk-computers.de>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

drivers/net/dsa/hirschmann/hellcreek.c

@@ -221,12 +221,11 @@ static void hellcreek_feature_detect(struct hellcreek *hellcreek)
 
 	features = hellcreek_read(hellcreek, HR_FEABITS0);
 
-	/* Currently we only detect the size of the FDB table */
+	/* Only detect the size of the FDB table. The size and current
+	 * utilization can be queried via devlink.
+	 */
 	hellcreek->fdb_entries = ((features & HR_FEABITS0_FDBBINS_MASK) >>
 			       HR_FEABITS0_FDBBINS_SHIFT) * 32;
-
-	dev_info(hellcreek->dev, "Feature detect: FDB entries=%zu\n",
-		 hellcreek->fdb_entries);
 }
 
 static enum dsa_tag_protocol hellcreek_get_tag_protocol(struct dsa_switch *ds,
@@ -1015,20 +1014,48 @@ static u64 hellcreek_devlink_vlan_table_get(void *priv)
 	return count;
 }
 
+static u64 hellcreek_devlink_fdb_table_get(void *priv)
+{
+	struct hellcreek *hellcreek = priv;
+	u64 count = 0;
+
+	/* Reading this register has side effects. Synchronize against the other
+	 * FDB operations.
+	 */
+	mutex_lock(&hellcreek->reg_lock);
+	count = hellcreek_read(hellcreek, HR_FDBMAX);
+	mutex_unlock(&hellcreek->reg_lock);
+
+	return count;
+}
+
 static int hellcreek_setup_devlink_resources(struct dsa_switch *ds)
 {
-	struct devlink_resource_size_params size_params;
+	struct devlink_resource_size_params size_vlan_params;
+	struct devlink_resource_size_params size_fdb_params;
 	struct hellcreek *hellcreek = ds->priv;
 	int err;
 
-	devlink_resource_size_params_init(&size_params, VLAN_N_VID,
+	devlink_resource_size_params_init(&size_vlan_params, VLAN_N_VID,
 					  VLAN_N_VID,
 					  1, DEVLINK_RESOURCE_UNIT_ENTRY);
 
+	devlink_resource_size_params_init(&size_fdb_params,
+					  hellcreek->fdb_entries,
+					  hellcreek->fdb_entries,
+					  1, DEVLINK_RESOURCE_UNIT_ENTRY);
+
 	err = dsa_devlink_resource_register(ds, "VLAN", VLAN_N_VID,
 					    HELLCREEK_DEVLINK_PARAM_ID_VLAN_TABLE,
 					    DEVLINK_RESOURCE_ID_PARENT_TOP,
-					    &size_params);
+					    &size_vlan_params);
+	if (err)
+		goto out;
+
+	err = dsa_devlink_resource_register(ds, "FDB", hellcreek->fdb_entries,
+					    HELLCREEK_DEVLINK_PARAM_ID_FDB_TABLE,
+					    DEVLINK_RESOURCE_ID_PARENT_TOP,
+					    &size_fdb_params);
 	if (err)
 		goto out;
 
@@ -1037,6 +1064,11 @@ static int hellcreek_setup_devlink_resources(struct dsa_switch *ds)
 					      hellcreek_devlink_vlan_table_get,
 					      hellcreek);
 
+	dsa_devlink_resource_occ_get_register(ds,
+					      HELLCREEK_DEVLINK_PARAM_ID_FDB_TABLE,
+					      hellcreek_devlink_fdb_table_get,
+					      hellcreek);
+
 	return 0;
 
 out:

drivers/net/dsa/hirschmann/hellcreek.h

@@ -301,6 +301,7 @@ struct hellcreek {
 /* Devlink resources */
 enum hellcreek_devlink_resource_id {
 	HELLCREEK_DEVLINK_PARAM_ID_VLAN_TABLE,
+	HELLCREEK_DEVLINK_PARAM_ID_FDB_TABLE,
 };
 
 #endif /* _HELLCREEK_H_ */