[PATCH net v2 0/2] net: dsa: mt7530: fix trapped frame forwarding and egress tagging

[Tao Gong]

This series resolves two issues in the MT7530 DSA switch driver preventing
trapped link-local control frames (such as STP BPDUs) from reaching the CPU
host when bridge VLAN filtering is enabled:

1. Commit 3ac85bcfd404 ("net: dsa: mt7530: preserve VLAN tags on trapped
   link-local frames") set MT7530_VLAN_EG_DISABLED to preserve VLAN tags,
   but in hardware this disables the per-packet override and causes
   trapped frames to follow the CPU port's active VLAN table (VAWD2) rule.
   When bridge VLAN filtering is active, the CPU port is in stack mode,
   causing incoming untagged BPDUs (01:80:C2:00:00:00) to be egressed with
   a VLAN tag, which userspace STP daemons (such as ustpd) and the kernel
   bridge drop. MT7530_VLAN_EG_CONSISTENT correctly preserves wire state
   (untagged frames stay untagged, tagged frames stay tagged).

2. On Airoha EN7581 and AN7583 switch IP, setting MT7531_CFC (0x04)
   CPU_PMAP alone is insufficient; the switch MAC forwarding control
   (MT753X_MFC, 0x10) must also have CPU_EN and CPU_PORT configured for
   trapped frames to exit to the CPU conduit.

Changes in v2:
  - Rebased onto net/main
    (git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git) adapting
    to mt7530_rmw() instead of net-next's regmap helpers, resolving the
    patch application failure on net-0 noted by Jakub Kicinski.
  - Carried over Lorenzo Bianconi's Acked-by on patch 2 as the underlying
    logic is unchanged.

Tao Gong (2):
  net: dsa: mt7530: use consistent egress tag for trapped link-local
    frames
  net: dsa: mt7530: trap frames to conduit in MFC on EN7581 and AN7583

 drivers/net/dsa/mt7530.c | 27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)


base-commit: 9c572a83037a7dcd653ba3a9cc468c16b857d0c9
-- 
2.55.0