net: mv643xx_eth: Factorize initial checksum and command preparation

Make the code more readable by moving the initial checksum setup
and the command/status preparation to its own function.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/marvell/mv643xx_eth.c b/drivers/net/ethernet/marvell/mv643xx_eth.c
index df1d1b9..14a0dbb 100644 (file)
--- a/drivers/net/ethernet/marvell/mv643xx_eth.c
+++ b/drivers/net/ethernet/marvell/mv643xx_eth.c
@@ -661,6 +661,64 @@ static inline unsigned int has_tiny_unaligned_frags(struct sk_buff *skb)
        return 0;
 }
 
+static inline __be16 sum16_as_be(__sum16 sum)
+{
+       return (__force __be16)sum;
+}
+
+static int skb_tx_csum(struct mv643xx_eth_private *mp, struct sk_buff *skb,
+                      u16 *l4i_chk, u32 *command, int length)
+{
+       int ret;
+       u32 cmd = 0;
+
+       if (skb->ip_summed == CHECKSUM_PARTIAL) {
+               int hdr_len;
+               int tag_bytes;
+
+               BUG_ON(skb->protocol != htons(ETH_P_IP) &&
+                      skb->protocol != htons(ETH_P_8021Q));
+
+               hdr_len = (void *)ip_hdr(skb) - (void *)skb->data;
+               tag_bytes = hdr_len - ETH_HLEN;
+
+               if (length - hdr_len > mp->shared->tx_csum_limit ||
+                   unlikely(tag_bytes & ~12)) {
+                       ret = skb_checksum_help(skb);
+                       if (!ret)
+                               goto no_csum;
+                       return ret;
+               }
+
+               if (tag_bytes & 4)
+                       cmd |= MAC_HDR_EXTRA_4_BYTES;
+               if (tag_bytes & 8)
+                       cmd |= MAC_HDR_EXTRA_8_BYTES;
+
+               cmd |= GEN_TCP_UDP_CHECKSUM |
+                          GEN_IP_V4_CHECKSUM   |
+                          ip_hdr(skb)->ihl << TX_IHL_SHIFT;
+
+               switch (ip_hdr(skb)->protocol) {
+               case IPPROTO_UDP:
+                       cmd |= UDP_FRAME;
+                       *l4i_chk = ntohs(sum16_as_be(udp_hdr(skb)->check));
+                       break;
+               case IPPROTO_TCP:
+                       *l4i_chk = ntohs(sum16_as_be(tcp_hdr(skb)->check));
+                       break;
+               default:
+                       WARN(1, "protocol not supported");
+               }
+       } else {
+no_csum:
+               /* Errata BTS #50, IHL must be 5 if no HW checksum */
+               cmd |= 5 << TX_IHL_SHIFT;
+       }
+       *command = cmd;
+       return 0;
+}
+
 static void txq_submit_frag_skb(struct tx_queue *txq, struct sk_buff *skb)
 {
        struct mv643xx_eth_private *mp = txq_to_mp(txq);
@@ -699,11 +757,6 @@ static void txq_submit_frag_skb(struct tx_queue *txq, struct sk_buff *skb)
        }
 }
 
-static inline __be16 sum16_as_be(__sum16 sum)
-{
-       return (__force __be16)sum;
-}
-
 static int txq_submit_skb(struct tx_queue *txq, struct sk_buff *skb)
 {
        struct mv643xx_eth_private *mp = txq_to_mp(txq);
@@ -712,53 +765,17 @@ static int txq_submit_skb(struct tx_queue *txq, struct sk_buff *skb)
        struct tx_desc *desc;
        u32 cmd_sts;
        u16 l4i_chk;
-       int length;
+       int length, ret;
 
-       cmd_sts = TX_FIRST_DESC | GEN_CRC | BUFFER_OWNED_BY_DMA;
+       cmd_sts = 0;
        l4i_chk = 0;
 
-       if (skb->ip_summed == CHECKSUM_PARTIAL) {
-               int hdr_len;
-               int tag_bytes;
-
-               BUG_ON(skb->protocol != htons(ETH_P_IP) &&
-                      skb->protocol != htons(ETH_P_8021Q));
-
-               hdr_len = (void *)ip_hdr(skb) - (void *)skb->data;
-               tag_bytes = hdr_len - ETH_HLEN;
-               if (skb->len - hdr_len > mp->shared->tx_csum_limit ||
-                   unlikely(tag_bytes & ~12)) {
-                       if (skb_checksum_help(skb) == 0)
-                               goto no_csum;
-                       dev_kfree_skb_any(skb);
-                       return 1;
-               }
-
-               if (tag_bytes & 4)
-                       cmd_sts |= MAC_HDR_EXTRA_4_BYTES;
-               if (tag_bytes & 8)
-                       cmd_sts |= MAC_HDR_EXTRA_8_BYTES;
-
-               cmd_sts |= GEN_TCP_UDP_CHECKSUM |
-                          GEN_IP_V4_CHECKSUM   |
-                          ip_hdr(skb)->ihl << TX_IHL_SHIFT;
-
-               switch (ip_hdr(skb)->protocol) {
-               case IPPROTO_UDP:
-                       cmd_sts |= UDP_FRAME;
-                       l4i_chk = ntohs(sum16_as_be(udp_hdr(skb)->check));
-                       break;
-               case IPPROTO_TCP:
-                       l4i_chk = ntohs(sum16_as_be(tcp_hdr(skb)->check));
-                       break;
-               default:
-                       BUG();
-               }
-       } else {
-no_csum:
-               /* Errata BTS #50, IHL must be 5 if no HW checksum */
-               cmd_sts |= 5 << TX_IHL_SHIFT;
+       ret = skb_tx_csum(mp, skb, &l4i_chk, &cmd_sts, skb->len);
+       if (ret) {
+               dev_kfree_skb_any(skb);
+               return ret;
        }
+       cmd_sts |= TX_FIRST_DESC | GEN_CRC | BUFFER_OWNED_BY_DMA;
 
        tx_index = txq->tx_curr_desc++;
        if (txq->tx_curr_desc == txq->tx_ring_size)