[PATCH net v2 1/3] mlxsw: core: Unregister EMAD trap using FORWARD action

From: Petr Machata <petrm@nvidia.com>
To: "David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	<netdev@vger.kernel.org>
Cc: Ido Schimmel <idosch@nvidia.com>, Petr Machata <petrm@nvidia.com>,
	<mlxsw@nvidia.com>, Jiri Pirko <jiri@resnulli.us>,
	Amit Cohen <amcohen@nvidia.com>, Simon Horman <horms@kernel.org>
Subject: [PATCH net v2 1/3] mlxsw: core: Unregister EMAD trap using FORWARD action
Date: Thu, 18 Apr 2024 15:46:06 +0200	[thread overview]
Message-ID: <753a89e14008fde08cb4a2c1e5f537b81d8eb2d6.1713446092.git.petrm@nvidia.com> (raw)
In-Reply-To: <cover.1713446092.git.petrm@nvidia.com>

From: Ido Schimmel <idosch@nvidia.com>

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>
---
 drivers/net/ethernet/mellanox/mlxsw/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/core.c b/drivers/net/ethernet/mellanox/mlxsw/core.c
index e4d7739bd7c8..4a79c0d7e7ad 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/core.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/core.c
@@ -849,7 +849,7 @@ static void mlxsw_emad_rx_listener_func(struct sk_buff *skb, u16 local_port,
 
 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_tlv_enable(struct mlxsw_core *mlxsw_core)
 {
-- 
2.43.0

