From: Scott Wood <scottwood@freescale.com>
Date: Wed, 16 May 2007 20:06:59 +0000 (-0500)
Subject: gianfar: Add I/O barriers when touching buffer descriptor ownership.
X-Git-Tag: v2.6.22-rc2~19
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3b6330ce2a3e1f152f79a6203f73d23356e243a7;p=pandora-kernel.git

gianfar: Add I/O barriers when touching buffer descriptor ownership.

The hardware must not see that is given ownership of a buffer until it is
completely written, and when the driver receives ownership of a buffer,
it must ensure that any other reads to the buffer reflect its final
state.  Thus, I/O barriers are added where required.

Without this patch, I have observed GCC reordering the setting of
bdp->length and bdp->status in gfar_new_skb.  Hardware reordering
was also theoretically possible.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
---

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