net: stmmac: fix RX coalesce frames counter

The RX refill path should set the IC bit once every rx_coal_frames
descriptors and leave the rest to the RX watchdog (RIWT), as done by
commit d429b66e2ebc ("net: stmmac: Implement RX Coalesce Frames
setting").

Since commit 6fa9d691b91a ("net: stmmac: Prevent divide-by-zero") the
counter is increased by N+1 for each descriptor and then compared
against N, so it is always reset to 0. With a non-zero rx-frames, IC is
therefore set on every descriptor and every frame raises an interrupt.

Fix this by counting one descriptor at a time in a helper used by both
stmmac_rx_refill() and stmmac_rx_refill_zc(). Platforms without RIWT
(IC on every descriptor) are unaffected.

Cc: stable+noautosel@kernel.org # never worked
Fixes: 6fa9d691b91a ("net: stmmac: Prevent divide-by-zero")
Signed-off-by: Pengfei Zhang <zhangfeionline@gmail.com>
Link: https://patch.msgid.link/20261009111138.320089-1-zhangfeionline@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions