net: airoha: move get_sport() callback at the beginning of airoha_enable_gdm2_loopback()

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>
Link: https://patch.msgid.link/20260608-airoha_enable_gdm2_loopback-minor-change-v1-1-1787a0f42b31@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c
index 504247c8bae9e6c8cae48b6315ee93f464168c67..872ec1e492c418eb5b3c2067791b50959d70885c 100644 (file)
--- a/drivers/net/ethernet/airoha/airoha_eth.c
+++ b/drivers/net/ethernet/airoha/airoha_eth.c
@@ -1908,6 +1908,10 @@ 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),
@@ -1937,10 +1941,6 @@ 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));