PCI reading without endian conversion

Matt Sealey matt at genesi-usa.com
Sat Feb 21 07:05:08 EST 2009


On Fri, Feb 20, 2009 at 1:11 PM, Ira Snyder <iws at 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 at genesi-usa.com>
Genesi, Manager, Developer Relations



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