blob: f09d542061a5cd83495a6ac05de0c754fd657723 [file] [log] [blame]
From fd1ea98df141781abf1783c0dc5de575e2b0a95f Mon Sep 17 00:00:00 2001
From: Remi Pommarel <>
Date: Sun, 8 Mar 2020 10:25:56 +0100
Subject: [PATCH] net: stmmac: dwmac1000: Disable ACS if enhanced descs are not
commit b723bd933980f4956dabc8a8d84b3e83be8d094c upstream.
ACS (auto PAD/FCS stripping) removes FCS off 802.3 packets (LLC) so that
there is no need to manually strip it for such packets. The enhanced DMA
descriptors allow to flag LLC packets so that the receiving callback can
use that to strip FCS manually or not. On the other hand, normal
descriptors do not support that.
Thus in order to not truncate LLC packet ACS should be disabled when
using normal DMA descriptors.
Fixes: 47dd7a540b8a0 ("net: add support for STMicroelectronics Ethernet controllers.")
Signed-off-by: Remi Pommarel <>
Signed-off-by: David S. Miller <>
Signed-off-by: Paul Gortmaker <>
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c
index 26bb1c15de1b..81af0f3f5cf9 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c
@@ -24,6 +24,7 @@
static void dwmac1000_core_init(struct mac_device_info *hw,
struct net_device *dev)
+ struct stmmac_priv *priv = netdev_priv(dev);
void __iomem *ioaddr = hw->pcsr;
u32 value = readl(ioaddr + GMAC_CONTROL);
int mtu = dev->mtu;
@@ -35,7 +36,7 @@ static void dwmac1000_core_init(struct mac_device_info *hw,
* Broadcom tags can look like invalid LLC/SNAP packets and cause the
* hardware to truncate packets on reception.
- if (netdev_uses_dsa(dev))
+ if (netdev_uses_dsa(dev) || !priv->plat->enh_desc)
if (mtu > 1500)