@@ -1323,6 +1323,24 @@ dma_error:
return 0;
}
+static inline int macb_clear_csum(struct sk_buff *skb)
+{
+ /* no change for packets without checksum offloading */
+ if (skb->ip_summed != CHECKSUM_PARTIAL)
+ return 0;
+
+ /* make sure we can modify the header */
+ if (unlikely(skb_cow_head(skb, 0)))
+ return -1;
+
+ /* initialize checksum field
+ * This is required - at least for Zynq, which otherwise calculates
+ * wrong UDP header checksums for UDP packets with UDP data len <=2
+ */
+ *(__sum16 *)(skb_checksum_start(skb) + skb->csum_offset) = 0;
+ return 0;
+}
+
static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
u16 queue_index = skb_get_queue_mapping(skb);
@@ -1362,6 +1380,11 @@ static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev)
return NETDEV_TX_BUSY;
}
+ if (macb_clear_csum(skb)) {
+ dev_kfree_skb_any(skb);
+ return NETDEV_TX_OK;
+ }
+
/* Map socket buffer for DMA transfer */
if (!macb_tx_map(bp, queue, skb)) {
dev_kfree_skb_any(skb);
I'm still struggling to get this fix right.. Changes since v2: - do not blindly modify SKB contents according to Dave's legitimate objection Changes since v1: - dropped disabling HW checksum offload for Zynq - initialize checksum similar to net/ethernet/freescale/fec_main.c -- >8 -- MACB/GEM needs the checksum field initialized to 0 to get correct results on transmit in all cases, e.g. on Zynq, UDP packets with payload <= 2 otherwise contain a wrong checksums. Signed-off-by: Helmut Buchsbaum <helmut.buchsbaum@gmail.com> --- drivers/net/ethernet/cadence/macb.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+)