When a port turns into an mrouter port, enable multicast flooding
on that port even if multicast flooding is disabled by user config. This
is necessary so that in a distributed system, the multicast packets
can be forwarded to the Querier when the multicast source is attached
to a Non-Querier bridge.

Consider the following scenario:

                 +--------------------+
                 |                    |
                 |      Snooping      |    +------------+
                 |      Bridge 1      |----| Listener 1 |
                 |     (Querier)      |    +------------+
                 |                    |
                 +--------------------+
                           |
                           |
                 +--------------------+
                 |    | mrouter |     |
+-----------+    |    +---------+     |
| MC Source |----|      Snooping      |
+-----------|    |      Bridge 2      |
                 |    (Non-Querier)   |
                 +--------------------+

In this scenario, Listener 1 will never receive multicast traffic
from MC Source if multicast flooding is disabled on the mrouter port on
Snooping Bridge 2.

Signed-off-by: Joseph Huang <[email protected]>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 86 ++++++++++++++++++++++++++++++--
 drivers/net/dsa/mv88e6xxx/chip.h |  1 +
 2 files changed, 83 insertions(+), 4 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 32a613c965b1..9831aa370921 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -47,6 +47,7 @@ struct mv88e6xxx_bridge {
        struct list_head head;
        struct net_device *br_dev;
        u16 ports;
+       u16 mrouter_ports;
        struct list_head br_mdb_list;
 };
 
@@ -2993,6 +2994,7 @@ static void mv88e6xxx_bridge_destroy(struct 
mv88e6xxx_bridge *mv_bridge)
        list_del(&mv_bridge->head);
 
        WARN_ON(mv_bridge->ports);
+       WARN_ON(mv_bridge->mrouter_ports);
        WARN_ON(!list_empty(&mv_bridge->br_mdb_list));
        kfree(mv_bridge);
 }
@@ -3010,6 +3012,19 @@ struct mv88e6xxx_bridge *mv88e6xxx_bridge_by_dev(struct 
mv88e6xxx_chip *chip,
        return NULL;
 }
 
+static
+struct mv88e6xxx_bridge *mv88e6xxx_bridge_by_port(struct mv88e6xxx_chip *chip,
+                                                 int port)
+{
+       struct mv88e6xxx_bridge *mv_bridge;
+
+       list_for_each_entry(mv_bridge, &chip->bridge_list, head)
+               if (mv_bridge->ports & BIT(port))
+                       return mv_bridge;
+
+       return NULL;
+}
+
 static struct mv88e6xxx_bridge *
 mv88e6xxx_bridge_get(struct mv88e6xxx_chip *chip, struct net_device *br_dev)
 {
@@ -6849,11 +6864,28 @@ static int mv88e6xxx_port_bridge_flags(struct 
dsa_switch *ds, int port,
 
        if (flags.mask & BR_MCAST_FLOOD) {
                bool multicast = !!(flags.val & BR_MCAST_FLOOD);
+               struct mv88e6xxx_bridge *mv_bridge;
+               struct mv88e6xxx_port *p;
+               bool mrouter;
 
-               err = chip->info->ops->port_set_mcast_flood(chip, port,
-                                                           multicast);
-               if (err)
-                       goto out;
+               mv_bridge = mv88e6xxx_bridge_by_port(chip, port);
+               if (!mv_bridge)
+                       return -EINVAL;
+
+               p = &chip->ports[port];
+               mrouter = !!(mv_bridge->mrouter_ports & BIT(port));
+
+               if (!mrouter) {
+                       err = chip->info->ops->port_set_mcast_flood(chip, port,
+                                                                   multicast);
+                       if (err)
+                               goto out;
+               }
+
+               if (multicast)
+                       p->flags |= MV88E6XXX_PORT_FLAG_MC_FLOOD;
+               else
+                       p->flags &= ~MV88E6XXX_PORT_FLAG_MC_FLOOD;
        }
 
        if (flags.mask & BR_BCAST_FLOOD) {
@@ -6883,6 +6915,51 @@ static int mv88e6xxx_port_bridge_flags(struct dsa_switch 
*ds, int port,
        return err;
 }
 
+static int mv88e6xxx_port_mrouter(struct dsa_switch *ds, int port,
+                                 bool mrouter,
+                                 struct netlink_ext_ack *extack)
+{
+       struct mv88e6xxx_chip *chip = ds->priv;
+       struct mv88e6xxx_bridge *mv_bridge;
+       struct mv88e6xxx_port *p;
+       bool old_mrouter;
+       bool mc_flood;
+       int err;
+
+       if (!chip->info->ops->port_set_mcast_flood)
+               return -EOPNOTSUPP;
+
+       mv_bridge = mv88e6xxx_bridge_by_port(chip, port);
+       if (!mv_bridge)
+               return -EINVAL;
+
+       old_mrouter = !!(mv_bridge->mrouter_ports & BIT(port));
+       if (mrouter == old_mrouter)
+               return 0;
+
+       p = &chip->ports[port];
+       mc_flood = !!(p->flags & MV88E6XXX_PORT_FLAG_MC_FLOOD);
+
+       mv88e6xxx_reg_lock(chip);
+
+       if (!mc_flood) {
+               err = chip->info->ops->port_set_mcast_flood(chip, port,
+                                                           mrouter);
+               if (err)
+                       goto out;
+       }
+
+       if (mrouter)
+               mv_bridge->mrouter_ports |= BIT(port);
+       else
+               mv_bridge->mrouter_ports &= ~BIT(port);
+
+out:
+       mv88e6xxx_reg_unlock(chip);
+
+       return err;
+}
+
 static bool mv88e6xxx_lag_can_offload(struct dsa_switch *ds,
                                      struct dsa_lag lag,
                                      struct netdev_lag_upper_info *info,
@@ -7199,6 +7276,7 @@ static const struct dsa_switch_ops mv88e6xxx_switch_ops = 
{
        .port_bridge_leave      = mv88e6xxx_port_bridge_leave,
        .port_pre_bridge_flags  = mv88e6xxx_port_pre_bridge_flags,
        .port_bridge_flags      = mv88e6xxx_port_bridge_flags,
+       .port_mrouter           = mv88e6xxx_port_mrouter,
        .port_stp_state_set     = mv88e6xxx_port_stp_state_set,
        .port_mst_state_set     = mv88e6xxx_port_mst_state_set,
        .port_fast_age          = mv88e6xxx_port_fast_age,
diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
index 205f6777c2ac..47e056dc7925 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.h
+++ b/drivers/net/dsa/mv88e6xxx/chip.h
@@ -274,6 +274,7 @@ struct mv88e6xxx_vlan {
 
 /* MacAuth Bypass Control Flag */
 #define MV88E6XXX_PORT_FLAG_MAB                BIT(0)
+#define MV88E6XXX_PORT_FLAG_MC_FLOOD   BIT(1)
 
 struct mv88e6xxx_port {
        struct mv88e6xxx_chip *chip;
-- 
2.17.1


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