From: "Richard Röjfors" <richard.rojfors@mocean-labs.com>
To: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Cc: spi-devel-general@lists.sourceforge.net,
Andrew Morton <akpm@linux-foundation.org>,
dbrownell@users.sourceforge.net, John Linn <John.Linn@xilinx.com>,
linuxppc-dev@ozlabs.org
Subject: Re: [PATCH 2/4] xilinx_spi: Switch to iomem functions and support little endian.
Date: Wed, 11 Nov 2009 15:54:39 +0100 [thread overview]
Message-ID: <4AFAD02F.9080305@mocean-labs.com> (raw)
In-Reply-To: <20091111144924.GG30489@zod.rchland.ibm.com>
Josh Boyer wrote:
> On Wed, Nov 11, 2009 at 03:38:34PM +0100, Richard Röjfors wrote:
>> This patch changes the out_(be)(8|16|32) and in_(be)(8|16|32) calls to iowrite(8|16|32)
>> and ioread(8|16|32). This to be able to build on platforms not supporting the in/out calls
>> for instance x86.
>>
>> Support is also added for little endian writes. In some systems the registers should be
>> accessed little endian rather than big endian.
>
> I wonder if you should make the endianness a config option. Right now you
> have a conditional check for every read and write. Does that impact
> performance at all?
It won't affect the performance noticeable.
In our case we need the possibility to run both endians using the same xilinx_spi module.
--Richard
next prev parent reply other threads:[~2009-11-11 16:00 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-11 14:38 [PATCH 2/4] xilinx_spi: Switch to iomem functions and support little endian Richard Röjfors
2009-11-11 14:49 ` Josh Boyer
2009-11-11 14:54 ` Richard Röjfors [this message]
2009-11-11 21:09 ` Grant Likely
2009-11-11 22:19 ` John Linn
2009-11-11 22:25 ` Grant Likely
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