[PATCH net 8/8] net: bcmgenet: mask DMA_TIMEOUT_MASK when reading DMA_RING0_TIMEOUT
From: Florian Fainelli <florian.fainelli@broadcom.com>
Date: 2026-09-18 00:14:16
Also in:
lkml
Subsystem:
broadcom genet ethernet driver, networking drivers, the rest · Maintainers:
Doug Berger, Florian Fainelli, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
bcmgenet_get_coalesce() reads DMA_RING0_TIMEOUT to calculate
rx_coalesce_usecs without masking out bits outside DMA_TIMEOUT_MASK
(16 bits). If upper bits are non-zero or contain status/flags, the
computed value of rx_coalesce_usecs returned to userspace via ethtool
becomes corrupted.
Mask the register read with DMA_TIMEOUT_MASK before computing the
timeout in microseconds.
Fixes: 4a29645bfe6c ("net: bcmgenet: Implement RX coalescing control knobs")
Assisted-by: LLM
Co-authored-by: Cursor [off-list ref]
Change-Id: I4c5b5019e764dbd0c7e51bd8c7365939a4736e44
---
drivers/net/ethernet/broadcom/genet/bcmgenet.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
index 3a6a2f075959..b15e64a484b4 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c@@ -852,7 +852,8 @@ static int bcmgenet_get_coalesce(struct net_device *dev, ec->rx_max_coalesced_frames = bcmgenet_rdma_ring_readl(priv, 0, DMA_MBUF_DONE_THRESH); ec->rx_coalesce_usecs = - bcmgenet_rdma_readl(priv, DMA_RING0_TIMEOUT) * 8192 / 1000; + (bcmgenet_rdma_readl(priv, DMA_RING0_TIMEOUT) & + DMA_TIMEOUT_MASK) * 8192 / 1000; for (i = 0; i <= priv->hw_params->rx_queues; i++) { ring = &priv->rx_rings[i];
--
2.34.1