realtek: dsa: Reelect primary port for a LAG

rtl93xx hardware supports trunk fdb entries. That requires driver to
translate port-fdb entry to trunk fdb entry if the port is part of a
LAG.

There is no standard way of indicating fdb entries for bond interfaces.

One can use debugfs interface l2_table to dump all the entries stored in
the hardware. Trunk FDB entries are now displayed properly with trunk ID
and participating ports

Co-developed-by: Sven Eckelmann <se@simonwunderlich.de>
Signed-off-by: Sven Eckelmann <se@simonwunderlich.de>
Signed-off-by: Harshal Gohel <hg@simonwunderlich.de>
Link: https://github.com/openwrt/openwrt/pull/21740
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/debugfs.c

@@ -268,6 +268,13 @@ static void l2_table_print_entry(struct seq_file *m, struct rtl838x_switch_priv
 			   e->vid, e->rvid);
 
 		seq_printf(m, "  port %d age %d", e->port, e->age);
+		if (e->is_trunk) {
+			seq_printf(m, "  trunk %d trunk_members: 0x%08llx non-primary: 0x%08llx primary-port: %d",
+				   e->trunk,
+				   priv->lags_port_members[e->trunk],
+				   priv->lag_non_primary,
+				   priv->lag_primary[e->trunk]);
+		}
 		if (e->is_static)
 			seq_puts(m, " static");
 		if (e->block_da)

target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/dsa.c

@@ -1865,6 +1865,39 @@ static int rtldsa_find_l2_cam_entry(struct rtl838x_switch_priv *priv, u64 seed,
 	return idx;
 }
 
+/**
+ * rtldsa_find_lag_group_from_port() - Find lag group of current port
+ * @priv: private data of rtldsa switch
+ * @port: port id of potential LAG member
+ * Return: -ENOENT when port does not belong to any lag group, lag id otherwise
+ */
+static int rtldsa_find_lag_group_from_port(struct rtl838x_switch_priv *priv, int port)
+{
+	if (!(priv->lagmembers & BIT_ULL(port)))
+		return -ENOENT;
+
+	/* port is a lag member */
+	for (int lag_group = 0; lag_group < MAX_LAGS; lag_group++) {
+		if (priv->lags_port_members[lag_group] & BIT_ULL(port))
+			return lag_group;
+	}
+
+	return -ENOENT;
+}
+
+/**
+ * rtldsa_93xx_prepare_lag_fdb() - Prepare fdb entry for LAG
+ * @e: L2 entry data
+ * @lag_group: lag id of the trunk group
+ */
+inline void rtldsa_93xx_prepare_lag_fdb(struct rtl838x_l2_entry *e, int lag_group)
+{
+	if (e && lag_group >= 0) {
+		e->is_trunk = true;
+		e->trunk = lag_group;
+	}
+}
+
 static int rtldsa_port_fdb_add(struct dsa_switch *ds, int port,
 			       const unsigned char *addr, u16 vid,
 			       const struct dsa_db db)
@@ -1874,10 +1907,16 @@ static int rtldsa_port_fdb_add(struct dsa_switch *ds, int port,
 	struct rtl838x_l2_entry e;
 	int err = 0, idx;
 	u64 seed = priv->r->l2_hash_seed(mac, vid);
+	int lag_group = rtldsa_find_lag_group_from_port(priv, port);
 
-	if (priv->lag_non_primary & BIT_ULL(port)) {
-		pr_debug("%s: %d is lag slave. ignore\n", __func__, port);
-		return 0;
+	if (lag_group >= 0 && priv->r->prepare_lag_fdb) {
+		priv->r->prepare_lag_fdb(&e, lag_group);
+	} else {
+		if (priv->lag_non_primary & BIT_ULL(port)) {
+			pr_debug("%s: %d is lag slave but prepare_lag_fdb is not supported. ignore\n",
+				 __func__, port);
+			return 0;
+		}
 	}
 
 	mutex_lock(&priv->reg_mutex);
@@ -1917,8 +1956,13 @@ static int rtldsa_port_fdb_del(struct dsa_switch *ds, int port,
 	struct rtl838x_l2_entry e;
 	int err = 0, idx;
 	u64 seed = priv->r->l2_hash_seed(mac, vid);
+	int lag_group = rtldsa_find_lag_group_from_port(priv, port);
+
+	if (lag_group >= 0 && priv->r->prepare_lag_fdb)
+		priv->r->prepare_lag_fdb(&e, lag_group);
 
 	pr_debug("In %s, mac %llx, vid: %d\n", __func__, mac, vid);
+
 	mutex_lock(&priv->reg_mutex);
 
 	idx = rtldsa_find_l2_hash_entry(priv, seed, true, &e);
@@ -1960,6 +2004,10 @@ static int rtldsa_port_fdb_dump(struct dsa_switch *ds, int port,
 		if (!e.valid)
 			continue;
 
+		// Ignore trunk fdb entries
+		if (e.is_trunk)
+			continue;
+
 		if (e.port == port || e.port == RTL930X_PORT_IGNORE)
 			cb(e.mac, e.vid, e.is_static, data);
 
@@ -1973,6 +2021,10 @@ static int rtldsa_port_fdb_dump(struct dsa_switch *ds, int port,
 		if (!e.valid)
 			continue;
 
+		// Ignore trunk fdb entries
+		if (e.is_trunk)
+			continue;
+
 		if (e.port == port)
 			cb(e.mac, e.vid, e.is_static, data);
 	}
@@ -2396,7 +2448,6 @@ static int rtldsa_port_lag_leave(struct dsa_switch *ds, int port,
 	}
 	pr_info("port_lag_del: group %d, port %d\n", group, port);
 	priv->lagmembers &= ~BIT_ULL(port);
-	priv->lag_primary[group] = -1;
 	priv->lag_non_primary &= ~BIT_ULL(port);
 	pr_debug("lag_members = %llX\n", priv->lagmembers);
 	err = rtl83xx_lag_del(priv->ds, group, port);
@@ -2405,6 +2456,19 @@ static int rtldsa_port_lag_leave(struct dsa_switch *ds, int port,
 		goto out;
 	}
 
+	/* To re-elect primary interface, just remove the first interface in
+	 * this-group's interfaces from non-primary
+	 */
+	if (priv->lags_port_members[group]) {
+		priv->lag_primary[group] = fls64(priv->lags_port_members[group]);
+		priv->lag_non_primary &= ~BIT_ULL(priv->lag_primary[group]);
+	}
+
+	/* No need to update fdb entries since they make use of trunk_id for entry.
+	 * The primary interface is only calculated at time of
+	 * port_fdb_dump
+	 */
+
 out:
 	mutex_unlock(&priv->reg_mutex);
 	return 0;

target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/rtl838x.h

@@ -1366,6 +1366,8 @@ struct rtldsa_config {
 	void (*led_init)(struct rtl838x_switch_priv *priv);
 	void (*qos_init)(struct rtl838x_switch_priv *priv);
 	int (*trk_mbr_ctr)(int group);
+	void (*lag_switch_init)(struct rtl838x_switch_priv *priv);
+	void (*prepare_lag_fdb)(struct rtl838x_l2_entry *e, int lag_group);
 	int (*lag_set_port_members)(struct rtl838x_switch_priv *priv, int group, u64 members,
 				    struct netdev_lag_upper_info *info);
 	int (*lag_setup_algomask)(struct rtl838x_switch_priv *priv, int group,
@@ -1449,6 +1451,8 @@ void rtl930x_dbgfs_init(struct rtl838x_switch_priv *priv);
 int rtldsa_93xx_lag_set_distribution_algorithm(struct rtl838x_switch_priv *priv,
 					       int group, int algoidx, u32 algomsk);
 
+void rtldsa_93xx_prepare_lag_fdb(struct rtl838x_l2_entry *e, int lag_group);
+
 void rtldsa_counters_lock_register(struct rtl838x_switch_priv *priv, int port)
 	__acquires(&priv->ports[port].counters.lock);
 void rtldsa_counters_unlock_register(struct rtl838x_switch_priv *priv, int port)

target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/rtl930x.c

@@ -2801,5 +2801,8 @@ const struct rtldsa_config rtldsa_930x_cfg = {
 	.set_receive_management_action = rtldsa_930x_set_receive_management_action,
 	.qos_init = rtldsa_930x_qos_init,
 	.trk_hash_ctrl = RTL930X_TRK_HASH_CTRL,
+	.prepare_lag_fdb = rtldsa_93xx_prepare_lag_fdb,
+	.lag_switch_init = rtldsa_93xx_lag_switch_init,
+	.lag_set_port_members = rtldsa_93xx_lag_set_port_members,
 	.lag_set_distribution_algorithm = rtldsa_93xx_lag_set_distribution_algorithm,
 };

target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/rtl931x.c

@@ -1925,5 +1925,8 @@ const struct rtldsa_config rtldsa_931x_cfg = {
 	.set_receive_management_action = rtldsa_931x_set_receive_management_action,
 	.qos_init = rtldsa_931x_qos_init,
 	.trk_hash_ctrl = RTL931X_TRK_HASH_CTRL,
+	.prepare_lag_fdb = rtldsa_93xx_prepare_lag_fdb,
+	.lag_switch_init = rtldsa_93xx_lag_switch_init,
+	.lag_set_port_members = rtldsa_93xx_lag_set_port_members,
 	.lag_set_distribution_algorithm = rtldsa_93xx_lag_set_distribution_algorithm,
 };