This is a note to let you know that I've just added the patch titled

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

to the 2.6.38-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     gianfar-fall-back-to-software-tcp-udp-checksum-on-older-controllers.patch
and it can be found in the queue-2.6.38 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From 4dbd99fd8453ae681dad8fc1e7aa2c05e16b0cc1 Mon Sep 17 00:00:00 2001
From: Alex Dubov <[email protected]>
Date: Wed, 16 Mar 2011 17:57:13 +0000
Subject: gianfar: Fall back to software tcp/udp checksum on older controllers


From: Alex Dubov <[email protected]>

[ Upstream commit 4363c2fddb1399b728ef21ee8101c148a311ea45 ]

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 <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/net/gianfar.c |   16 ++++++++++++++--
 drivers/net/gianfar.h |    1 +
 2 files changed, 15 insertions(+), 2 deletions(-)

--- a/drivers/net/gianfar.c
+++ b/drivers/net/gianfar.c
@@ -950,6 +950,11 @@ static void gfar_detect_errata(struct gf
                        (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);
@@ -2156,8 +2161,15 @@ static int gfar_start_xmit(struct sk_buf
        /* 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)) {
--- 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


Patches currently in stable-queue which might be from [email protected] are

queue-2.6.38/gianfar-fall-back-to-software-tcp-udp-checksum-on-older-controllers.patch

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