tree 954eea2e62f50366c8a63681571f50f98bd83a55
parent e960fc5c7d9144b1ce80dda9891ca7dfc656c078
author Dale Farnsworth <[EMAIL PROTECTED]> Tue, 23 Aug 2005 05:53:29 -0700
committer Jeff Garzik <[EMAIL PROTECTED]> Tue, 23 Aug 2005 08:51:34 -0400

[PATCH] mv643xx: add workaround for HW checksum generation bug

[PATCH] [NET] mv643xx: add workaround for HW checksum generation bug

The hardware checksum generator on the mv64xxx occasionally generates
an incorrect checksum.  This patch works around the issue and enables
hardware checksum generation.

Signed-off-by: Dale Farnsworth <[EMAIL PROTECTED]>
Signed-off-by: Jeff Garzik <[EMAIL PROTECTED]>

 drivers/net/mv643xx_eth.c |   29 ++++++++++++++++++-----------
 drivers/net/mv643xx_eth.h |    4 +++-
 2 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/drivers/net/mv643xx_eth.c b/drivers/net/mv643xx_eth.c
--- a/drivers/net/mv643xx_eth.c
+++ b/drivers/net/mv643xx_eth.c
@@ -1157,16 +1157,20 @@ static int mv643xx_eth_start_xmit(struct
        if (!skb_shinfo(skb)->nr_frags) {
 linear:
                if (skb->ip_summed != CHECKSUM_HW) {
+                       /* Errata BTS #50, IHL must be 5 if no HW checksum */
                        pkt_info.cmd_sts = ETH_TX_ENABLE_INTERRUPT |
-                                       ETH_TX_FIRST_DESC | ETH_TX_LAST_DESC;
+                                          ETH_TX_FIRST_DESC |
+                                          ETH_TX_LAST_DESC |
+                                          5 << ETH_TX_IHL_SHIFT;
                        pkt_info.l4i_chk = 0;
                } else {
-                       u32 ipheader = skb->nh.iph->ihl << 11;
 
                        pkt_info.cmd_sts = ETH_TX_ENABLE_INTERRUPT |
-                                       ETH_TX_FIRST_DESC | ETH_TX_LAST_DESC |
-                                       ETH_GEN_TCP_UDP_CHECKSUM |
-                                       ETH_GEN_IP_V_4_CHECKSUM | ipheader;
+                                          ETH_TX_FIRST_DESC |
+                                          ETH_TX_LAST_DESC |
+                                          ETH_GEN_TCP_UDP_CHECKSUM |
+                                          ETH_GEN_IP_V_4_CHECKSUM |
+                                          skb->nh.iph->ihl << ETH_TX_IHL_SHIFT;
                        /* CPU already calculated pseudo header checksum. */
                        if (skb->nh.iph->protocol == IPPROTO_UDP) {
                                pkt_info.cmd_sts |= ETH_UDP_FRAME;
@@ -1193,7 +1197,6 @@ linear:
                stats->tx_bytes += pkt_info.byte_cnt;
        } else {
                unsigned int frag;
-               u32 ipheader;
 
                /* Since hardware can't handle unaligned fragments smaller
                 * than 9 bytes, if we find any, we linearize the skb
@@ -1222,12 +1225,16 @@ linear:
                                                        DMA_TO_DEVICE);
                pkt_info.l4i_chk = 0;
                pkt_info.return_info = 0;
-               pkt_info.cmd_sts = ETH_TX_FIRST_DESC;
 
-               if (skb->ip_summed == CHECKSUM_HW) {
-                       ipheader = skb->nh.iph->ihl << 11;
-                       pkt_info.cmd_sts |= ETH_GEN_TCP_UDP_CHECKSUM |
-                                       ETH_GEN_IP_V_4_CHECKSUM | ipheader;
+               if (skb->ip_summed != CHECKSUM_HW)
+                       /* Errata BTS #50, IHL must be 5 if no HW checksum */
+                       pkt_info.cmd_sts = ETH_TX_FIRST_DESC |
+                                          5 << ETH_TX_IHL_SHIFT;
+               else {
+                       pkt_info.cmd_sts = ETH_TX_FIRST_DESC |
+                                          ETH_GEN_TCP_UDP_CHECKSUM |
+                                          ETH_GEN_IP_V_4_CHECKSUM |
+                                          skb->nh.iph->ihl << ETH_TX_IHL_SHIFT;
                        /* CPU already calculated pseudo header checksum. */
                        if (skb->nh.iph->protocol == IPPROTO_UDP) {
                                pkt_info.cmd_sts |= ETH_UDP_FRAME;
diff --git a/drivers/net/mv643xx_eth.h b/drivers/net/mv643xx_eth.h
--- a/drivers/net/mv643xx_eth.h
+++ b/drivers/net/mv643xx_eth.h
@@ -49,7 +49,7 @@
 /* Checksum offload for Tx works for most packets, but
  * fails if previous packet sent did not use hw csum
  */
-#undef MV643XX_CHECKSUM_OFFLOAD_TX
+#define        MV643XX_CHECKSUM_OFFLOAD_TX
 #define        MV643XX_NAPI
 #define        MV643XX_TX_FAST_REFILL
 #undef MV643XX_RX_QUEUE_FILL_ON_TASK   /* Does not work, yet */
@@ -217,6 +217,8 @@
 #define ETH_TX_ENABLE_INTERRUPT                        (BIT23)
 #define ETH_AUTO_MODE                          (BIT30)
 
+#define ETH_TX_IHL_SHIFT                       11
+
 /* typedefs */
 
 typedef enum _eth_func_ret_status {
-
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