From: Matt Sealey <matt@genesi-usa.com>
To: Ira Snyder <iws@ovro.caltech.edu>
Cc: PowerPC dev list <linuxppc-dev@ozlabs.org>
Subject: Re: PCI reading without endian conversion
Date: Fri, 20 Feb 2009 14:05:08 -0600 [thread overview]
Message-ID: <b5e2fc790902201205t4bd03373w7e7624fce60f5eb0@mail.gmail.com> (raw)
In-Reply-To: <20090220191108.GA21163@ovro.caltech.edu>
On Fri, Feb 20, 2009 at 1:11 PM, Ira Snyder <iws@ovro.caltech.edu> wrote:
> On Fri, Feb 20, 2009 at 12:57:36PM -0600, Matt Sealey wrote:
>
> I'm pretty sure memcpy_fromio() and memcpy_toio() will get you what you
> want. They don't change byte ordering.
Are they guaranteed to only do 32-bit, aligned accesses?
I made some cheats on my CPLD to ignore byte enables and so on,
because it makes the design cleaner and easier to read (for students)
plus, saves a ton of logic cells. It's totally within the PCI
standard, but it means if you do a byte read memcpy() you get.. very
weird results (i.e. not great).
--
Matt Sealey <matt@genesi-usa.com>
Genesi, Manager, Developer Relations
next prev parent reply other threads:[~2009-02-20 20:05 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-20 18:57 PCI reading without endian conversion Matt Sealey
2009-02-20 19:11 ` Ira Snyder
2009-02-20 20:05 ` Matt Sealey [this message]
2009-02-20 21:07 ` Ira Snyder
2009-02-20 21:56 ` Matt Sealey
2009-02-20 23:50 ` Ira Snyder
2009-02-21 4:33 ` Benjamin Herrenschmidt
2009-02-23 10:37 ` Geert Uytterhoeven
2009-02-20 22:37 ` Benjamin Herrenschmidt
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