net: bcmgenet: if UMAC was suspended in SW_RESET, restore it to SW_RESET

When the revised suspend/resume sequence was introduced this led to an edge
case where the TX is left disabled in the following sequence.

1. phy link is down, so UMAC is held in reset and then network interface
   is WoL enabled
2. Enter suspend, bcmgenet_wol_power_down_cfg() enables UMAC_RX since MAC
   is in SW_RESET
4. Enter resume, UMAC_RX is left enabled. Since we only enable UMAC_TX
   and UMAC_RX in SW_RESET. The UMAC_TX is never enabled again on link up.

The issue was hit in production and I verified the sequence keeps
the TX  disabled in my standalone test. I tested on an internal
development board with bcm77122, but should be reproducible
on any genet HW that supports power management.

Fixes: 254f3239dd07 ("net: bcmgenet: revise suspend/resume")
Signed-off-by: Justin Chen <justin.chen@broadcom.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Nicolai Buchwitz <nb@tipi-net.de>
Link: https://patch.msgid.link/20260930230634.3132729-1-justin.chen@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions