[PATCH/RFC net] net: dsa: lantiq_gswip: honor dsa_db passed to port_fdb_{add,del}

[Daniel Golle <daniel@makrotopia.org>]

Commit c9eb3e0f8701 ("net: dsa: Add support for learning FDB through
notification") added a dev_close() call "to indicate inconsistent
situation" when we could not delete an FDB entry from the port. In case
of the lantiq_gswip driver this is problematic on standalone ports for
which all calls to either .port_fdb_add() or .port_fdb_del() would just
always return -EINVAL as adding or removing FDB entries is currently
only supported for ports which are a member of a bridge.

As since commit c26933639b54 ("net: dsa: request drivers to perform FDB
isolation") the dsa_db is passed to the .port_fdb_add() or
.port_fdb_del() calls we can use that to set the FID accordingly,
similar to how it was for bridge ports, and to FID 0 for standalone
ports. In order for FID 0 to work at all we also need to set bit 1 in
val[1], so always set it.

This solution was found in a downstream driver provided by MaxLinear
(which is the current owner of the former Lantiq switch IP) under
GPL-2.0. Import the implementation and the copyright headers from that
driver.

Fixes: c9eb3e0f8701 ("net: dsa: Add support for learning FDB through notification")
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
 drivers/net/dsa/lantiq_gswip.c | 55 ++++++++++++++++++++--------------
 1 file changed, 33 insertions(+), 22 deletions(-)

diff --git a/drivers/net/dsa/lantiq_gswip.c b/drivers/net/dsa/lantiq_gswip.c
index 6eb3140d4044..fed86b2d78fc 100644
--- a/drivers/net/dsa/lantiq_gswip.c
+++ b/drivers/net/dsa/lantiq_gswip.c
@@ -2,9 +2,11 @@
 /*
  * Lantiq / Intel GSWIP switch driver for VRX200, xRX300 and xRX330 SoCs
  *
- * Copyright (C) 2010 Lantiq Deutschland
- * Copyright (C) 2012 John Crispin <john@phrozen.org>
+ * Copyright (C) 2023 - 2024 MaxLinear Inc.
+ * Copyright (C) 2022 Snap One, LLC.  All rights reserved.
  * Copyright (C) 2017 - 2019 Hauke Mehrtens <hauke@hauke-m.de>
+ * Copyright (C) 2012 John Crispin <john@phrozen.org>
+ * Copyright (C) 2010 Lantiq Deutschland
  *
  * The VLAN and bridge model the GSWIP hardware uses does not directly
  * matches the model DSA uses.
@@ -239,6 +241,7 @@
 #define  GSWIP_TABLE_MAC_BRIDGE_KEY3_FID	GENMASK(5, 0)	/* Filtering identifier */
 #define  GSWIP_TABLE_MAC_BRIDGE_VAL0_PORT	GENMASK(7, 4)	/* Port on learned entries */
 #define  GSWIP_TABLE_MAC_BRIDGE_VAL1_STATIC	BIT(0)		/* Static, non-aging entry */
+#define  GSWIP_TABLE_MAC_BRIDGE_VAL1_VALID	BIT(1)		/* Valid bit */
 
 #define XRX200_GPHY_FW_ALIGN	(16 * 1024)
 
@@ -1349,30 +1352,37 @@ static void gswip_port_stp_state_set(struct dsa_switch *ds, int port, u8 state)
 }
 
 static int gswip_port_fdb(struct dsa_switch *ds, int port,
-			  const unsigned char *addr, u16 vid, bool add)
+			  const unsigned char *addr, u16 vid, struct dsa_db db,
+			  bool add)
 {
-	struct net_device *bridge = dsa_port_bridge_dev_get(dsa_to_port(ds, port));
 	struct gswip_priv *priv = ds->priv;
 	struct gswip_pce_table_entry mac_bridge = {0,};
-	unsigned int max_ports = priv->hw_info->max_ports;
 	int fid = -1;
-	int i;
 	int err;
+	int i;
 
-	if (!bridge)
-		return -EINVAL;
-
-	for (i = max_ports; i < ARRAY_SIZE(priv->vlans); i++) {
-		if (priv->vlans[i].bridge == bridge) {
-			fid = priv->vlans[i].fid;
-			break;
+	switch (db.type) {
+	case DSA_DB_BRIDGE:
+		for (i = 0; i < ARRAY_SIZE(priv->vlans); i++) {
+			if (priv->vlans[i].bridge == db.bridge.dev) {
+				fid = priv->vlans[i].fid;
+				break;
+			}
 		}
-	}
-
-	if (fid == -1) {
-		dev_err(priv->dev, "no FID found for bridge %s\n",
-			bridge->name);
-		return -EINVAL;
+		if (fid == -1) {
+			dev_err(priv->dev, "Port %d not part of a bridge\n", port);
+			return -EINVAL;
+		}
+		break;
+	case DSA_DB_PORT:
+		if (dsa_is_cpu_port(ds, port) &&
+			dsa_fdb_present_in_other_db(ds, port, addr, vid, db))
+			return 0;
+		/* FID of a standalone / single port bridge */
+		fid = 0;
+		break;
+	default:
+		return -EOPNOTSUPP;
 	}
 
 	mac_bridge.table = GSWIP_TABLE_MAC_BRIDGE;
@@ -1382,7 +1392,8 @@ static int gswip_port_fdb(struct dsa_switch *ds, int port,
 	mac_bridge.key[2] = addr[1] | (addr[0] << 8);
 	mac_bridge.key[3] = FIELD_PREP(GSWIP_TABLE_MAC_BRIDGE_KEY3_FID, fid);
 	mac_bridge.val[0] = add ? BIT(port) : 0; /* port map */
-	mac_bridge.val[1] = GSWIP_TABLE_MAC_BRIDGE_VAL1_STATIC;
+	mac_bridge.val[1] = add ? (GSWIP_TABLE_MAC_BRIDGE_VAL1_STATIC |
+				   GSWIP_TABLE_MAC_BRIDGE_VAL1_VALID) : 0;
 	mac_bridge.valid = add;
 
 	err = gswip_pce_table_entry_write(priv, &mac_bridge);
@@ -1396,14 +1407,14 @@ static int gswip_port_fdb_add(struct dsa_switch *ds, int port,
 			      const unsigned char *addr, u16 vid,
 			      struct dsa_db db)
 {
-	return gswip_port_fdb(ds, port, addr, vid, true);
+	return gswip_port_fdb(ds, port, addr, vid, db, true);
 }
 
 static int gswip_port_fdb_del(struct dsa_switch *ds, int port,
 			      const unsigned char *addr, u16 vid,
 			      struct dsa_db db)
 {
-	return gswip_port_fdb(ds, port, addr, vid, false);
+	return gswip_port_fdb(ds, port, addr, vid, db, false);
 }
 
 static int gswip_port_fdb_dump(struct dsa_switch *ds, int port,
-- 
2.50.1