mlxsw: spectrum_span: Support mirror-to-VLAN

Offload "tc action mirred mirror" to a device that is a vlan device on
top of a front-panel port device. The hardware encapsulates the mirrored
packets in a VLAN tag. That includes the case that the mirrored traffic
is already VLAN-tagged--in that case the monitor traffic will be
double-tagged, just like in the software path.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c

@@ -235,6 +235,14 @@ mlxsw_sp_span_entry_bridge(const struct net_device *br_dev,
 	return dev;
 }
 
+static struct net_device *
+mlxsw_sp_span_entry_vlan(const struct net_device *vlan_dev,
+			 u16 *p_vid)
+{
+	*p_vid = vlan_dev_vlan_id(vlan_dev);
+	return vlan_dev_real_dev(vlan_dev);
+}
+
 static __maybe_unused int
 mlxsw_sp_span_entry_tunnel_parms_common(struct net_device *l3edev,
 					union mlxsw_sp_l3addr saddr,
@@ -477,6 +485,61 @@ struct mlxsw_sp_span_entry_ops mlxsw_sp_span_entry_ops_gretap6 = {
 };
 #endif
 
+static bool
+mlxsw_sp_span_vlan_can_handle(const struct net_device *dev)
+{
+	return is_vlan_dev(dev) &&
+	       mlxsw_sp_port_dev_check(vlan_dev_real_dev(dev));
+}
+
+static int
+mlxsw_sp_span_entry_vlan_parms(const struct net_device *to_dev,
+			       struct mlxsw_sp_span_parms *sparmsp)
+{
+	struct net_device *real_dev;
+	u16 vid;
+
+	if (!(to_dev->flags & IFF_UP))
+		return mlxsw_sp_span_entry_unoffloadable(sparmsp);
+
+	real_dev = mlxsw_sp_span_entry_vlan(to_dev, &vid);
+	sparmsp->dest_port = netdev_priv(real_dev);
+	sparmsp->vid = vid;
+	return 0;
+}
+
+static int
+mlxsw_sp_span_entry_vlan_configure(struct mlxsw_sp_span_entry *span_entry,
+				   struct mlxsw_sp_span_parms sparms)
+{
+	struct mlxsw_sp_port *dest_port = sparms.dest_port;
+	struct mlxsw_sp *mlxsw_sp = dest_port->mlxsw_sp;
+	u8 local_port = dest_port->local_port;
+	char mpat_pl[MLXSW_REG_MPAT_LEN];
+	int pa_id = span_entry->id;
+
+	mlxsw_reg_mpat_pack(mpat_pl, pa_id, local_port, true,
+			    MLXSW_REG_MPAT_SPAN_TYPE_REMOTE_ETH);
+	mlxsw_reg_mpat_eth_rspan_pack(mpat_pl, sparms.vid);
+
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(mpat), mpat_pl);
+}
+
+static void
+mlxsw_sp_span_entry_vlan_deconfigure(struct mlxsw_sp_span_entry *span_entry)
+{
+	mlxsw_sp_span_entry_deconfigure_common(span_entry,
+					MLXSW_REG_MPAT_SPAN_TYPE_REMOTE_ETH);
+}
+
+static const
+struct mlxsw_sp_span_entry_ops mlxsw_sp_span_entry_ops_vlan = {
+	.can_handle = mlxsw_sp_span_vlan_can_handle,
+	.parms = mlxsw_sp_span_entry_vlan_parms,
+	.configure = mlxsw_sp_span_entry_vlan_configure,
+	.deconfigure = mlxsw_sp_span_entry_vlan_deconfigure,
+};
+
 static const
 struct mlxsw_sp_span_entry_ops *const mlxsw_sp_span_entry_types[] = {
 	&mlxsw_sp_span_entry_ops_phys,
@@ -486,6 +549,7 @@ struct mlxsw_sp_span_entry_ops *const mlxsw_sp_span_entry_types[] = {
 #if IS_ENABLED(CONFIG_IPV6_GRE)
 	&mlxsw_sp_span_entry_ops_gretap6,
 #endif
+	&mlxsw_sp_span_entry_ops_vlan,
 };
 
 static int