net: dsa: add MDB support

Add SWITCHDEV_OBJ_ID_PORT_MDB support to the DSA layer.
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/dsa/dsa.txt

@@ -584,6 +584,29 @@ of DSA, would be the its port-based VLAN, used by the associated bridge device.
   function that the driver has to call for each MAC address known to be behind
   the given port. A switchdev object is used to carry the VID and FDB info.
 
+- port_mdb_prepare: bridge layer function invoked when the bridge prepares the
+  installation of a multicast database entry. If the operation is not supported,
+  this function should return -EOPNOTSUPP to inform the bridge code to fallback
+  to a software implementation. No hardware setup must be done in this function.
+  See port_fdb_add for this and details.
+
+- port_mdb_add: bridge layer function invoked when the bridge wants to install
+  a multicast database entry, the switch hardware should be programmed with the
+  specified address in the specified VLAN ID in the forwarding database
+  associated with this VLAN ID.
+
+Note: VLAN ID 0 corresponds to the port private database, which, in the context
+of DSA, would be the its port-based VLAN, used by the associated bridge device.
+
+- port_mdb_del: bridge layer function invoked when the bridge wants to remove a
+  multicast database entry, the switch hardware should be programmed to delete
+  the specified MAC address from the specified VLAN ID if it was mapped into
+  this port forwarding database.
+
+- port_mdb_dump: bridge layer function invoked with a switchdev callback
+  function that the driver has to call for each MAC address known to be behind
+  the given port. A switchdev object is used to carry the VID and MDB info.
+
 TODO
 ====
 

include/net/dsa.h

@@ -234,6 +234,7 @@ static inline u8 dsa_upstream_port(struct dsa_switch *ds)
 struct switchdev_trans;
 struct switchdev_obj;
 struct switchdev_obj_port_fdb;
+struct switchdev_obj_port_mdb;
 struct switchdev_obj_port_vlan;
 
 struct dsa_switch_ops {
@@ -369,6 +370,21 @@ struct dsa_switch_ops {
 	int	(*port_fdb_dump)(struct dsa_switch *ds, int port,
 				 struct switchdev_obj_port_fdb *fdb,
 				 int (*cb)(struct switchdev_obj *obj));
+
+	/*
+	 * Multicast database
+	 */
+	int	(*port_mdb_prepare)(struct dsa_switch *ds, int port,
+				    const struct switchdev_obj_port_mdb *mdb,
+				    struct switchdev_trans *trans);
+	void	(*port_mdb_add)(struct dsa_switch *ds, int port,
+				const struct switchdev_obj_port_mdb *mdb,
+				struct switchdev_trans *trans);
+	int	(*port_mdb_del)(struct dsa_switch *ds, int port,
+				const struct switchdev_obj_port_mdb *mdb);
+	int	(*port_mdb_dump)(struct dsa_switch *ds, int port,
+				 struct switchdev_obj_port_mdb *mdb,
+				 int (*cb)(struct switchdev_obj *obj));
 };
 
 void register_switch_driver(struct dsa_switch_ops *type);

net/dsa/slave.c

@@ -290,6 +290,50 @@ static int dsa_slave_port_fdb_dump(struct net_device *dev,
 	return -EOPNOTSUPP;
 }
 
+static int dsa_slave_port_mdb_add(struct net_device *dev,
+				  const struct switchdev_obj_port_mdb *mdb,
+				  struct switchdev_trans *trans)
+{
+	struct dsa_slave_priv *p = netdev_priv(dev);
+	struct dsa_switch *ds = p->parent;
+
+	if (switchdev_trans_ph_prepare(trans)) {
+		if (!ds->ops->port_mdb_prepare || !ds->ops->port_mdb_add)
+			return -EOPNOTSUPP;
+
+		return ds->ops->port_mdb_prepare(ds, p->port, mdb, trans);
+	}
+
+	ds->ops->port_mdb_add(ds, p->port, mdb, trans);
+
+	return 0;
+}
+
+static int dsa_slave_port_mdb_del(struct net_device *dev,
+				  const struct switchdev_obj_port_mdb *mdb)
+{
+	struct dsa_slave_priv *p = netdev_priv(dev);
+	struct dsa_switch *ds = p->parent;
+
+	if (ds->ops->port_mdb_del)
+		return ds->ops->port_mdb_del(ds, p->port, mdb);
+
+	return -EOPNOTSUPP;
+}
+
+static int dsa_slave_port_mdb_dump(struct net_device *dev,
+				   struct switchdev_obj_port_mdb *mdb,
+				   switchdev_obj_dump_cb_t *cb)
+{
+	struct dsa_slave_priv *p = netdev_priv(dev);
+	struct dsa_switch *ds = p->parent;
+
+	if (ds->ops->port_mdb_dump)
+		return ds->ops->port_mdb_dump(ds, p->port, mdb, cb);
+
+	return -EOPNOTSUPP;
+}
+
 static int dsa_slave_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 {
 	struct dsa_slave_priv *p = netdev_priv(dev);
@@ -412,6 +456,10 @@ static int dsa_slave_port_obj_add(struct net_device *dev,
 					     SWITCHDEV_OBJ_PORT_FDB(obj),
 					     trans);
 		break;
+	case SWITCHDEV_OBJ_ID_PORT_MDB:
+		err = dsa_slave_port_mdb_add(dev, SWITCHDEV_OBJ_PORT_MDB(obj),
+					     trans);
+		break;
 	case SWITCHDEV_OBJ_ID_PORT_VLAN:
 		err = dsa_slave_port_vlan_add(dev,
 					      SWITCHDEV_OBJ_PORT_VLAN(obj),
@@ -435,6 +483,9 @@ static int dsa_slave_port_obj_del(struct net_device *dev,
 		err = dsa_slave_port_fdb_del(dev,
 					     SWITCHDEV_OBJ_PORT_FDB(obj));
 		break;
+	case SWITCHDEV_OBJ_ID_PORT_MDB:
+		err = dsa_slave_port_mdb_del(dev, SWITCHDEV_OBJ_PORT_MDB(obj));
+		break;
 	case SWITCHDEV_OBJ_ID_PORT_VLAN:
 		err = dsa_slave_port_vlan_del(dev,
 					      SWITCHDEV_OBJ_PORT_VLAN(obj));
@@ -459,6 +510,10 @@ static int dsa_slave_port_obj_dump(struct net_device *dev,
 					      SWITCHDEV_OBJ_PORT_FDB(obj),
 					      cb);
 		break;
+	case SWITCHDEV_OBJ_ID_PORT_MDB:
+		err = dsa_slave_port_mdb_dump(dev, SWITCHDEV_OBJ_PORT_MDB(obj),
+					      cb);
+		break;
 	case SWITCHDEV_OBJ_ID_PORT_VLAN:
 		err = dsa_slave_port_vlan_dump(dev,
 					       SWITCHDEV_OBJ_PORT_VLAN(obj),