mlxsw: core: Unregister EMAD trap using FORWARD action

[ Upstream commit 976c44af48141cd8595601c0af2a19a43c5b228b ]

The device's manual (PRM - Programmer's Reference Manual) classifies the
trap that is used to deliver EMAD responses as an "event trap". Among
other things, it means that the only actions that can be associated with
the trap are TRAP and FORWARD (NOP).

Currently, during driver de-initialization the driver unregisters the
trap by setting its action to DISCARD, which violates the above
guideline. Future firmware versions will prevent such misuses by
returning an error. This does not prevent the driver from working, but
an error will be printed to the kernel log during module removal /
devlink reload:

mlxsw_spectrum 0000:03:00.0: Reg cmd access status failed (status=7(bad parameter))
mlxsw_spectrum 0000:03:00.0: Reg cmd access failed (reg_id=7003(hpkt),type=write)

Suppress the error message by aligning the driver to the manual and use
a FORWARD (NOP) action when unregistering the trap.

Fixes: 4ec14b7634b2 ("mlxsw: Add interface to access registers and process events")
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Amit Cohen <amcohen@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Link: https://lore.kernel.org/r/753a89e14008fde08cb4a2c1e5f537b81d8eb2d6.1713446092.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/ethernet/mellanox/mlxsw/core.c b/drivers/net/ethernet/mellanox/mlxsw/core.c
index 2d39bade89e3347e52f668b9c1bfbc634925758f..bb9299481b45b68c80ae9866d5384d11d524ed7e 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlxsw/core.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/core.c
@@ -566,7 +566,7 @@ free_skb:
 
 static const struct mlxsw_listener mlxsw_emad_rx_listener =
        MLXSW_RXL(mlxsw_emad_rx_listener_func, ETHEMAD, TRAP_TO_CPU, false,
-                 EMAD, DISCARD);
+                 EMAD, FORWARD);
 
 static int mlxsw_emad_init(struct mlxsw_core *mlxsw_core)
 {