750 and Discovery II coherency with PCI....

Benjamin Herrenschmidt benh at kernel.crashing.org
Wed Aug 4 10:42:44 EST 2004

On Tue, 2004-08-03 at 13:26, Steven J. Hill wrote:
> Greetings.
> I am writing a device driver for a PMC card that is nothing
> fancy. It is not a PCI-X card though. My Linux driver properly
> detects the device, 'ioremaps' the PCI IO and MEM regions then
> attempts to start writing the devices registers for setup
> and configuration. I am not getting valid reads and there
> appears to be some coherency issues. I have verified that no
> other drivers or resources in the system are utilizing the
> addresses that are returned to me from 'ioremap'. I have the
> following code snippet:

There is no coherency issues with non cacheable (ioremap'ed)
access of that kind... Note that if you are dealing with IO space,
then you should use inX/outX accessors and not ioremap.


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