mv643xx_eth: fix byte order when checksum offload is enabled

The Marvell Orion system on chips have an integrated mv643xx MAC.  On these
little endian ARM devices mv643xx will oops when checksum offload is
enabled.  Swapping the byte order of the protocol and checksum solves this
problem.

Signed-off-by: Byron Bradley <byron.bbradley@gmail.com>
Cc: Dale Farnsworth <dale@farnsworth.org>
Cc: Manish Lachwani <mlachwani@mvista.com>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/mv643xx_eth.c

@@ -1652,6 +1652,11 @@ static void eth_tx_fill_frag_descs(struct mv643xx_private *mp,
 	}
 }
 
+static inline __be16 sum16_as_be(__sum16 sum)
+{
+	return (__force __be16)sum;
+}
+
 /**
  * eth_tx_submit_descs_for_skb - submit data from an skb to the tx hw
  *
@@ -1689,7 +1694,7 @@ static void eth_tx_submit_descs_for_skb(struct mv643xx_private *mp,
 	desc->buf_ptr = dma_map_single(NULL, skb->data, length, DMA_TO_DEVICE);
 
 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
-		BUG_ON(skb->protocol != ETH_P_IP);
+		BUG_ON(skb->protocol != htons(ETH_P_IP));
 
 		cmd_sts |= ETH_GEN_TCP_UDP_CHECKSUM |
 			   ETH_GEN_IP_V_4_CHECKSUM  |
@@ -1698,10 +1703,10 @@ static void eth_tx_submit_descs_for_skb(struct mv643xx_private *mp,
 		switch (ip_hdr(skb)->protocol) {
 		case IPPROTO_UDP:
 			cmd_sts |= ETH_UDP_FRAME;
-			desc->l4i_chk = udp_hdr(skb)->check;
+			desc->l4i_chk = ntohs(sum16_as_be(udp_hdr(skb)->check));
 			break;
 		case IPPROTO_TCP:
-			desc->l4i_chk = tcp_hdr(skb)->check;
+			desc->l4i_chk = ntohs(sum16_as_be(tcp_hdr(skb)->check));
 			break;
 		default:
 			BUG();