net: dsa: mv88e6xxx: check hardware VLAN in use

The DSA drivers now have access to the VLAN prepare phase and the bridge
net_device. It is easier to check for overlapping bridges from within
the driver. Thus add such check in mv88e6xxx_port_vlan_prepare.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/dsa/mv88e6xxx.c b/drivers/net/dsa/mv88e6xxx.c
index 2e515e8a95fe5e776ec603413a022dee20062d5a..685dcb047979cabf00f8371022e115b9eec46ea7 100644 (file)
--- a/drivers/net/dsa/mv88e6xxx.c
+++ b/drivers/net/dsa/mv88e6xxx.c
@@ -1471,14 +1471,78 @@ static int _mv88e6xxx_vlan_init(struct dsa_switch *ds, u16 vid,
        return 0;
 }
 
+static int mv88e6xxx_port_check_hw_vlan(struct dsa_switch *ds, int port,
+                                       u16 vid_begin, u16 vid_end)
+{
+       struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
+       struct mv88e6xxx_vtu_stu_entry vlan;
+       int i, err;
+
+       if (!vid_begin)
+               return -EOPNOTSUPP;
+
+       mutex_lock(&ps->smi_mutex);
+
+       err = _mv88e6xxx_vtu_vid_write(ds, vid_begin - 1);
+       if (err)
+               goto unlock;
+
+       do {
+               err = _mv88e6xxx_vtu_getnext(ds, &vlan);
+               if (err)
+                       goto unlock;
+
+               if (!vlan.valid)
+                       break;
+
+               if (vlan.vid > vid_end)
+                       break;
+
+               for (i = 0; i < ps->num_ports; ++i) {
+                       if (dsa_is_dsa_port(ds, i) || dsa_is_cpu_port(ds, i))
+                               continue;
+
+                       if (vlan.data[i] ==
+                           GLOBAL_VTU_DATA_MEMBER_TAG_NON_MEMBER)
+                               continue;
+
+                       if (ps->ports[i].bridge_dev ==
+                           ps->ports[port].bridge_dev)
+                               break; /* same bridge, check next VLAN */
+
+                       netdev_warn(ds->ports[port],
+                                   "hardware VLAN %d already used by %s\n",
+                                   vlan.vid,
+                                   netdev_name(ps->ports[i].bridge_dev));
+                       err = -EOPNOTSUPP;
+                       goto unlock;
+               }
+       } while (vlan.vid < vid_end);
+
+unlock:
+       mutex_unlock(&ps->smi_mutex);
+
+       return err;
+}
+
 int mv88e6xxx_port_vlan_prepare(struct dsa_switch *ds, int port,
                                const struct switchdev_obj_port_vlan *vlan,
                                struct switchdev_trans *trans)
 {
+       int err;
+
        /* We reserve a few VLANs to isolate unbridged ports */
        if (vlan->vid_end >= 4000)
                return -EOPNOTSUPP;
 
+       /* If the requested port doesn't belong to the same bridge as the VLAN
+        * members, do not support it (yet) and fallback to software VLAN.
+        */
+       err = mv88e6xxx_port_check_hw_vlan(ds, port, vlan->vid_begin,
+                                          vlan->vid_end);
+       if (err)
+               return err;
+
        /* We don't need any dynamic resource from the kernel (yet),
         * so skip the prepare phase.
         */