net: ti: icssg-prueth: Add HSR multicast FDB port membership management

In HSR offload mode, multicast addresses can be added via HSR master
(hsr0) or directly to slave ports (eth1/eth2). The FDB must track port
membership: P0 (0x1) for HSR master, P1 (0x2) for slave port 1, and P2
(0x4) for slave port 2. When the same address is added from multiple
paths, memberships must accumulate.

Implement a hybrid approach using __dev_mc_sync() callbacks to track
basic add/delete operations, checking netdev_hw_addr->synced to
distinguish HSR-synced addresses from direct additions. Post-process
to handle overlapping memberships by checking refcount:
- refcount=2 with synced=1: HSR only (P0)
- refcount>=3 with synced=1: HSR + direct (P0|P1/P2)
- synced=0 with P0 set: HSR removed, clean up orphaned P0

On add operations, accumulate new membership with existing ports. On
delete operations, remove only the specific port and clean up orphaned
P0 bits if needed.

Add error handling for icssg_fdb_lookup() which can return negative
error codes (e.g., -ETIMEDOUT). On lookup failure in add/delete path,
default to no existing membership. In the post-processing path, skip
the address update to avoid corrupting FDB entries with garbage values.

VLAN Interface Handling:
Add support for multicast addresses added to VLAN interfaces on the HSR
master (e.g., hsr0.7). These addresses require P0 (HSR master) bit to be
set along with the port bits, since VLAN-tagged packets use separate FDB
entries per VLAN ID. Without P0, the HSR master would not receive
multicast packets on VLAN interfaces.

Track whether the add/del operation came from a VLAN interface path and
set P0 when in HSR offload mode with VLAN interfaces. Update orphaned P0
cleanup logic to preserve P0 for VLAN interfaces.

Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260311082923.2962937-1-danishanwar@ti.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions