From 84411f73b8849c494fc6dd3bb6b5f10ee6e58a5b Mon Sep 17 00:00:00 2001 From: Ezequiel Garcia Date: Mon, 19 May 2014 13:59:57 -0300 Subject: [PATCH] net: mv643xx_eth: Avoid setting the initial TCP checksum As specified in the datasheet, the driver can set the "L4Chk_Mode" flag (bit 10) in the Tx descriptor command/status to specify that a frame is not IP fragmented and that the controller is in charge of generating the TCP/IP checksum. This must be used together with the "GL4chk" flag (bit 17). These two flags allow to avoid setting the initial TCP checksum in the l4i_chk field of the Tx descriptor, which is needed to support software TSO. Signed-off-by: Ezequiel Garcia Signed-off-by: David S. Miller --- drivers/net/ethernet/marvell/mv643xx_eth.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/marvell/mv643xx_eth.c b/drivers/net/ethernet/marvell/mv643xx_eth.c index 14a0dbb..5ad19d2 100644 --- a/drivers/net/ethernet/marvell/mv643xx_eth.c +++ b/drivers/net/ethernet/marvell/mv643xx_eth.c @@ -250,6 +250,7 @@ struct tx_desc { #define GEN_TCP_UDP_CHECKSUM 0x00020000 #define UDP_FRAME 0x00010000 #define MAC_HDR_EXTRA_4_BYTES 0x00008000 +#define GEN_TCP_UDP_CHK_FULL 0x00000400 #define MAC_HDR_EXTRA_8_BYTES 0x00000200 #define TX_IHL_SHIFT 11 @@ -695,17 +696,19 @@ static int skb_tx_csum(struct mv643xx_eth_private *mp, struct sk_buff *skb, if (tag_bytes & 8) cmd |= MAC_HDR_EXTRA_8_BYTES; - cmd |= GEN_TCP_UDP_CHECKSUM | + cmd |= GEN_TCP_UDP_CHECKSUM | GEN_TCP_UDP_CHK_FULL | GEN_IP_V4_CHECKSUM | ip_hdr(skb)->ihl << TX_IHL_SHIFT; + /* TODO: Revisit this. With the usage of GEN_TCP_UDP_CHK_FULL + * it seems we don't need to pass the initial checksum. */ switch (ip_hdr(skb)->protocol) { case IPPROTO_UDP: cmd |= UDP_FRAME; - *l4i_chk = ntohs(sum16_as_be(udp_hdr(skb)->check)); + *l4i_chk = 0; break; case IPPROTO_TCP: - *l4i_chk = ntohs(sum16_as_be(tcp_hdr(skb)->check)); + *l4i_chk = 0; break; default: WARN(1, "protocol not supported"); -- 2.7.4