[PATCH net-next] net: airoha: move get_sport() callback at the beginning of airoha_enable_gdm2_loopback()

[PATCH net-next] net: airoha: move get_sport() callback at the beginning of airoha_enable_gdm2_loopback()

[Lorenzo Bianconi]

Move the get_sport() callback invocation at the beginning of
airoha_enable_gdm2_loopback() routine in order to avoid leaving the
hardware in a partially configured state if get_sport() fails.
Previously, get_sport() was called after GDM2 forwarding, loopback,
channel, length, VIP and IFC registers had already been programmed.
A failure at that point would return an error leaving GDM2 with
loopback enabled but WAN port, PPE CPU port and flow control mappings
not configured.
Performing the get_sport() lookup before any register write guarantees
the routine either completes the full configuration sequence or exits
with no side effects on the hardware.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/ethernet/airoha/airoha_eth.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c
index 5a8e84fa9918..cbc0f4079df0 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.c
+++ b/drivers/net/ethernet/airoha/airoha_eth.c
@@ -1905,6 +1905,10 @@ static int airoha_enable_gdm2_loopback(struct airoha_gdm_dev *dev)
 	u32 val, pse_port, chan;
 	int i, src_port;
 
+	src_port = eth->soc->ops.get_sport(port, dev->nbq);
+	if (src_port < 0)
+		return src_port;
+
 	airoha_set_gdm_port_fwd_cfg(eth, REG_GDM_FWD_CFG(AIROHA_GDM2_IDX),
 				    FE_PSE_PORT_DROP);
 	airoha_fe_clear(eth, REG_GDM_FWD_CFG(AIROHA_GDM2_IDX),
@@ -1934,10 +1938,6 @@ static int airoha_enable_gdm2_loopback(struct airoha_gdm_dev *dev)
 	airoha_fe_clear(eth, REG_FE_VIP_PORT_EN, BIT(AIROHA_GDM2_IDX));
 	airoha_fe_clear(eth, REG_FE_IFC_PORT_EN, BIT(AIROHA_GDM2_IDX));
 
-	src_port = eth->soc->ops.get_sport(port, dev->nbq);
-	if (src_port < 0)
-		return src_port;
-
 	airoha_fe_rmw(eth, REG_FE_WAN_PORT,
 		      WAN1_EN_MASK | WAN1_MASK | WAN0_MASK,
 		      FIELD_PREP(WAN0_MASK, src_port));

---
base-commit: 903db046d5579bef0ea699eae4b279dd6455fc9f
change-id: 20260608-airoha_enable_gdm2_loopback-minor-change-fda3a3351a06

Best regards,
-- 
Lorenzo Bianconi <lorenzo@kernel.org>

Re: [PATCH net-next] net: airoha: move get_sport() callback at the beginning of airoha_enable_gdm2_loopback()

[Simon Horman]

On Mon, Jun 08, 2026 at 11:24:15PM +0200, Lorenzo Bianconi wrote:
> Move the get_sport() callback invocation at the beginning of
> airoha_enable_gdm2_loopback() routine in order to avoid leaving the
> hardware in a partially configured state if get_sport() fails.
> Previously, get_sport() was called after GDM2 forwarding, loopback,
> channel, length, VIP and IFC registers had already been programmed.
> A failure at that point would return an error leaving GDM2 with
> loopback enabled but WAN port, PPE CPU port and flow control mappings
> not configured.
> Performing the get_sport() lookup before any register write guarantees
> the routine either completes the full configuration sequence or exits
> with no side effects on the hardware.
> 
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>

Reviewed-by: Simon Horman <horms@kernel.org>