[ 33/48] sky2: fix checksum bit management on some chips

[Ben Hutchings]

3.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: stephen hemminger <shemminger@xxxxxxxxxx>

[ Upstream commit 5ff0feac88ced864f44adb145142269196fa79d9 ]

The newer flavors of Yukon II use a different method for receive
checksum offload. This is indicated in the driver by the SKY2_HW_NEW_LE
flag. On these newer chips, the BMU_ENA_RX_CHKSUM should not be set.

The driver would get incorrectly toggle the bit, enabling the old
checksum logic on these chips and cause a BUG_ON() assertion. If
receive checksum was toggled via ethtool.

Reported-by: Kirill Smelkov <kirr@xxxxxxxxxx>
Signed-off-by: Stephen Hemminger <shemminger@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/marvell/sky2.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/marvell/sky2.c b/drivers/net/ethernet/marvell/sky2.c
index 65c51ff..11ddd838 100644
--- a/drivers/net/ethernet/marvell/sky2.c
+++ b/drivers/net/ethernet/marvell/sky2.c
@@ -4361,10 +4361,12 @@ static int sky2_set_features(struct net_device *dev, u32 features)
 	struct sky2_port *sky2 = netdev_priv(dev);
 	u32 changed = dev->features ^ features;
 
-	if (changed & NETIF_F_RXCSUM) {
-		u32 on = features & NETIF_F_RXCSUM;
-		sky2_write32(sky2->hw, Q_ADDR(rxqaddr[sky2->port], Q_CSR),
-			     on ? BMU_ENA_RX_CHKSUM : BMU_DIS_RX_CHKSUM);
+	if ((changed & NETIF_F_RXCSUM) &&
+	    !(sky2->hw->flags & SKY2_HW_NEW_LE)) {
+		sky2_write32(sky2->hw,
+			     Q_ADDR(rxqaddr[sky2->port], Q_CSR),
+			     (features & NETIF_F_RXCSUM)
+			     ? BMU_ENA_RX_CHKSUM : BMU_DIS_RX_CHKSUM);
 	}
 
 	if (changed & NETIF_F_RXHASH)


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