From: Steve.Glendinning@smsc.com
To: Magnus Damm <magnus.damm@gmail.com>
Cc: davem@davemloft.net, Ian.Saturley@smsc.com, iwamatsu@nigauri.org,
lethal@linux-sh.org, netdev@vger.kernel.org
Subject: Re: [PATCH] smsc911x: add fifo byteswap support
Date: Mon, 27 Apr 2009 08:40:49 +0100 [thread overview]
Message-ID: <OF7ABB7A00.E22FC2BA-ON802575A2.005A9008-802575A5.002A2FDC@smsc.com> (raw)
In-Reply-To: <aec7e5c30904231815x79d6f4e8g2e53de1fdeb7a73b@mail.gmail.com>
Hi Magnus,
Slight correction: the newer devices *can* handle this in hardware, there
are registers to control this swapping but the driver doesn't currently
use them. If I see a suitably broken design with a newer device I'll
submit a patch to add this.
Looks great otherwise, thanks for adding the "health warning" :-)
Regards,
--
Steve Glendinning
SMSC GmbH
m: +44 777 933 9124
e: steve.glendinning@smsc.com
Magnus Damm <magnus.damm@gmail.com> wrote on 24/04/2009 02:15:03:
> On Thu, Apr 23, 2009 at 12:21 AM, <Steve.Glendinning@smsc.com> wrote:
> > Magnus Damm <magnus.damm@gmail.com> wrote on 22/04/2009 15:55:53:
> >> This patch adds fifo byteswap support to the smsc911x driver.
>
> > Performance will be suboptimal with this software byteswapping,
> > so I think we should also add a comment to stress that this is
> > a "last resort" workaround for broken hardware.
>
> Good idea. How about adding the following to the header file right
> before the SMSC911X_SWAP_FIFO definition:
>
> /*
> * SMSC911X_SWAP_FIFO:
> * Enables software byte swap for fifo data. Should only be used as a
> * "last resort" in the case of big endian mode on boards with
incorrectly
> * routed data bus to older devices such as LAN9118. Newer devices such
as
> * LAN9221 handle this in hardware.
> */
>
> Let me know if you want to improve the comment somehow, otherwise I'll
> just update the patch and repost a V2.
>
> Cheers,
>
> / magnus
prev parent reply other threads:[~2009-04-27 7:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-22 14:55 [PATCH] smsc911x: add fifo byteswap support Magnus Damm
2009-04-22 15:21 ` Steve.Glendinning
2009-04-23 2:09 ` Paul Mundt
2009-04-23 11:33 ` Steve.Glendinning
2009-04-24 1:15 ` Magnus Damm
2009-04-27 7:40 ` Steve.Glendinning [this message]
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