[PATCH net v2] net: ethernet: adi: adin1110: mask the RX IRQ of the port being stopped

[Yuehong Wu]

adin1110_net_stop() programs the RX-ready interrupt mask of the wrong
port: it uses ADIN2111_RX_RDY_IRQ (the second port's bit) when stopping
port 0 and ADIN1110_RX_RDY_IRQ (the first port's bit) when stopping
port 1, while adin1110_port_rx_ready() uses the opposite mapping, port 0
-> ADIN1110_RX_RDY and port 1 -> ADIN2111_P2_RX_RDY.

The port being stopped therefore keeps its own RX interrupt enabled
while the peer's is masked.  On ADIN2111 that stalls RX on the peer port;
on ADIN1110 the RX interrupt is never masked at all.  As the interrupt is
level triggered and adin1110_read_frames() skips the FIFO while
netif_oper_up() is false, the stopped port also keeps re-raising its
interrupt with nobody draining the FIFO.

Swap the two bits so the port being stopped masks its own interrupt.

Found by code review while comparing the bit mapping against
adin1110_port_rx_ready().  I do not have access to ADIN1110 or ADIN2111
hardware, so this was only compile-tested (CONFIG_ADIN1110=m, x86_64),
not exercised on a device.

Fixes: bc93e19d088b ("net: ethernet: adi: Add ADIN1110 support")
Signed-off-by: Yuehong Wu <wuyuehong@xxxxxxxxxxxxxxxxxxxx>
---
v2:
- Cc the netdev maintainers, as flagged by the cc_maintainers CI check on v1.
- Explain how the issue was found and that the change was only compile-tested,
  no hardware access (netdev guideline for patches found by code review).
v1: https://lore.kernel.org/all/20261103-adin1110-net-stop-1-yuehongwu@xxxxxxxxxxxxxxxxxxxx/

 drivers/net/ethernet/adi/adin1110.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/adi/adin1110.c b/drivers/net/ethernet/adi/adin1110.c
index 53fac3d..abdc160 100644
--- a/drivers/net/ethernet/adi/adin1110.c
+++ b/drivers/net/ethernet/adi/adin1110.c
@@ -945,7 +945,7 @@ static int adin1110_net_stop(struct net_device *net_dev)
 	u32 mask;
 	int ret;
 
-	mask = !port_priv->nr ? ADIN2111_RX_RDY_IRQ : ADIN1110_RX_RDY_IRQ;
+	mask = !port_priv->nr ? ADIN1110_RX_RDY_IRQ : ADIN2111_RX_RDY_IRQ;
 
 	/* Disable RX RDY IRQs */
 	mutex_lock(&priv->lock);
-- 
2.43.0