From: David Hawkins <dwh@ovro•caltech.edu>
To: Matt Porter <mporter@kernel•crashing.org>
Cc: linuxppc-embedded@ozlabs•org
Subject: Re: Yosemite/440EP why are readl()/ioread32() setup to readlittle-endian?
Date: Wed, 01 Feb 2006 10:04:15 -0800 [thread overview]
Message-ID: <43E0F81F.4050005@ovro.caltech.edu> (raw)
In-Reply-To: <20060201104405.C16064@cox.net>
Matt,
In the same vein as the readl()/writel() question, what
are the assumptions regarding memcpy_toio and memcpy_fromio?
If the memcpy_to/fromio operations are intended only
for access to PCI devices, then they should also inherently
perform little-endianness conversion. For the test driver
I was working on, I did *not* find this the case, eg.
I implemented the test driver read() and write() using the
memcpy_to/fromio calls, and the data transfers occur
in big-endian (well, 'native' mode, since I also test the
same test driver with the PCI adapter in an x86 system).
If memcpy_to/fromio can be used in a more general context,
then I can see why they operate in native mode.
Just looking for enlightenment.
Cheers
Dave
next prev parent reply other threads:[~2006-02-01 18:02 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-01 11:19 Yosemite/440EP why are readl()/ioread32() setup to readlittle-endian? Jenkins, Clive
2006-02-01 17:02 ` David Hawkins
2006-02-01 17:44 ` Matt Porter
2006-02-01 17:53 ` David Hawkins
2006-02-01 18:04 ` David Hawkins [this message]
2006-02-01 18:11 ` Eugene Surovegin
2006-02-01 18:20 ` David Hawkins
2006-02-01 18:23 ` Eugene Surovegin
2006-02-01 21:14 ` Peter Korsgaard
2006-02-02 0:54 ` Kumar Gala
2006-02-02 3:07 ` Matt Porter
2006-02-02 8:09 ` Peter Korsgaard
2006-02-02 9:08 ` Eugene Surovegin
2006-02-02 17:34 ` Dale Farnsworth
2006-02-02 14:21 ` Matt Porter
-- strict thread matches above, loose matches on Subject: below --
2006-02-01 18:35 Jenkins, Clive
2006-02-01 20:35 ` David Hawkins
2006-02-02 9:35 Jenkins, Clive
2006-02-02 9:46 ` Eugene Surovegin
2006-02-02 14:37 ` Matt Porter
2006-02-02 17:45 ` Eugene Surovegin
2006-02-02 18:16 ` Matt Porter
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