net: dsa: mv88e6xxx: Remove some bureaucracy around querying the VTU

The hardware has a somewhat quirky protocol for reading out the VTU
entry for a particular VID. But there is no reason why we cannot
create a better API for ourselves in the driver.
Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx/chip.c

@@ -1502,13 +1502,23 @@ static int mv88e6xxx_vtu_setup(struct mv88e6xxx_chip *chip)
 	return mv88e6xxx_g1_vtu_flush(chip);
 }
 
-static int mv88e6xxx_vtu_getnext(struct mv88e6xxx_chip *chip,
+static int mv88e6xxx_vtu_get(struct mv88e6xxx_chip *chip, u16 vid,
 			     struct mv88e6xxx_vtu_entry *entry)
 {
+	int err;
+
 	if (!chip->info->ops->vtu_getnext)
 		return -EOPNOTSUPP;
 
-	return chip->info->ops->vtu_getnext(chip, entry);
+	entry->vid = vid ? vid - 1 : mv88e6xxx_max_vid(chip);
+	entry->valid = false;
+
+	err = chip->info->ops->vtu_getnext(chip, entry);
+
+	if (entry->vid != vid)
+		entry->valid = false;
+
+	return err;
 }
 
 static int mv88e6xxx_vtu_walk(struct mv88e6xxx_chip *chip,
@@ -1615,19 +1625,13 @@ static int mv88e6xxx_port_check_hw_vlan(struct dsa_switch *ds, int port,
 	if (dsa_is_dsa_port(ds, port) || dsa_is_cpu_port(ds, port))
 		return 0;
 
-	vlan.vid = vid - 1;
-	vlan.valid = false;
-
-	err = mv88e6xxx_vtu_getnext(chip, &vlan);
+	err = mv88e6xxx_vtu_get(chip, vid, &vlan);
 	if (err)
 		return err;
 
 	if (!vlan.valid)
 		return 0;
 
-	if (vlan.vid != vid)
-		return 0;
-
 	for (i = 0; i < mv88e6xxx_num_ports(chip); ++i) {
 		if (dsa_is_dsa_port(ds, i) || dsa_is_cpu_port(ds, i))
 			continue;
@@ -1709,15 +1713,12 @@ static int mv88e6xxx_port_db_load_purge(struct mv88e6xxx_chip *chip, int port,
 		if (err)
 			return err;
 	} else {
-		vlan.vid = vid - 1;
-		vlan.valid = false;
-
-		err = mv88e6xxx_vtu_getnext(chip, &vlan);
+		err = mv88e6xxx_vtu_get(chip, vid, &vlan);
 		if (err)
 			return err;
 
 		/* switchdev expects -EOPNOTSUPP to honor software VLANs */
-		if (vlan.vid != vid || !vlan.valid)
+		if (!vlan.valid)
 			return -EOPNOTSUPP;
 
 		fid = vlan.fid;
@@ -1994,14 +1995,11 @@ static int mv88e6xxx_port_vlan_join(struct mv88e6xxx_chip *chip, int port,
 	struct mv88e6xxx_vtu_entry vlan;
 	int i, err;
 
-	vlan.vid = vid - 1;
-	vlan.valid = false;
-
-	err = mv88e6xxx_vtu_getnext(chip, &vlan);
+	err = mv88e6xxx_vtu_get(chip, vid, &vlan);
 	if (err)
 		return err;
 
-	if (vlan.vid != vid || !vlan.valid) {
+	if (!vlan.valid) {
 		memset(&vlan, 0, sizeof(vlan));
 
 		err = mv88e6xxx_atu_new(chip, &vlan.fid);
@@ -2097,17 +2095,14 @@ static int mv88e6xxx_port_vlan_leave(struct mv88e6xxx_chip *chip,
 	if (!vid)
 		return -EOPNOTSUPP;
 
-	vlan.vid = vid - 1;
-	vlan.valid = false;
-
-	err = mv88e6xxx_vtu_getnext(chip, &vlan);
+	err = mv88e6xxx_vtu_get(chip, vid, &vlan);
 	if (err)
 		return err;
 
 	/* If the VLAN doesn't exist in hardware or the port isn't a member,
 	 * tell switchdev that this VLAN is likely handled in software.
 	 */
-	if (vlan.vid != vid || !vlan.valid ||
+	if (!vlan.valid ||
 	    vlan.member[port] == MV88E6XXX_G1_VTU_DATA_MEMBER_TAG_NON_MEMBER)
 		return -EOPNOTSUPP;