gianfar: Fall back to software tcp/udp checksum on older controllers

As specified by errata eTSEC49 of MPC8548 and errata eTSEC12 of MPC83xx,
older revisions of gianfar controllers will be unable to calculate a TCP/UDP
packet checksum for some alignments of the appropriate FCB. This patch checks
for FCB alignment on such controllers and falls back to software checksumming
if the alignment is known to be bad.

Signed-off-by: Alex Dubov <oakad@yahoo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/gianfar.c b/drivers/net/gianfar.c
index ccb231c4d9334bbe49336eeee5f8491e0c8e321b..2a0ad9a501bbea1d99a5ba9b819f7856a34c1346 100644 (file)
--- a/drivers/net/gianfar.c
+++ b/drivers/net/gianfar.c
@@ -949,6 +949,11 @@ static void gfar_detect_errata(struct gfar_private *priv)
                        (pvr == 0x80861010 && (mod & 0xfff9) == 0x80c0))
                priv->errata |= GFAR_ERRATA_A002;
 
+       /* MPC8313 Rev < 2.0, MPC8548 rev 2.0 */
+       if ((pvr == 0x80850010 && mod == 0x80b0 && rev < 0x0020) ||
+                       (pvr == 0x80210020 && mod == 0x8030 && rev == 0x0020))
+               priv->errata |= GFAR_ERRATA_12;
+
        if (priv->errata)
                dev_info(dev, "enabled errata workarounds, flags: 0x%x\n",
                         priv->errata);
@@ -2154,8 +2159,15 @@ static int gfar_start_xmit(struct sk_buff *skb, struct net_device *dev)
        /* Set up checksumming */
        if (CHECKSUM_PARTIAL == skb->ip_summed) {
                fcb = gfar_add_fcb(skb);
-               lstatus |= BD_LFLAG(TXBD_TOE);
-               gfar_tx_checksum(skb, fcb);
+               /* as specified by errata */
+               if (unlikely(gfar_has_errata(priv, GFAR_ERRATA_12)
+                            && ((unsigned long)fcb % 0x20) > 0x18)) {
+                       __skb_pull(skb, GMAC_FCB_LEN);
+                       skb_checksum_help(skb);
+               } else {
+                       lstatus |= BD_LFLAG(TXBD_TOE);
+                       gfar_tx_checksum(skb, fcb);
+               }
        }
 
        if (vlan_tx_tag_present(skb)) {

diff --git a/drivers/net/gianfar.h b/drivers/net/gianfar.h
index 54de4135e932b9dd2d92eedd32cf0338a20f3011..ec5d595ce2e265a342ed2c92cb479e202a239e37 100644 (file)
--- a/drivers/net/gianfar.h
+++ b/drivers/net/gianfar.h
@@ -1039,6 +1039,7 @@ enum gfar_errata {
        GFAR_ERRATA_74          = 0x01,
        GFAR_ERRATA_76          = 0x02,
        GFAR_ERRATA_A002        = 0x04,
+       GFAR_ERRATA_12          = 0x08, /* a.k.a errata eTSEC49 */
 };
 
 /* Struct stolen almost completely (and shamelessly) from the FCC enet source