Re: [PATCH] ioremap_cached()

Andi Kleen
2006-03-30T20:28:09Z

On Thursday 30 March 2006 22:21, Kumar Gala wrote:
>
> On Mar 30, 2006, at 2:17 PM, Andi Kleen wrote:
>
> > On Thursday 30 March 2006 22:14, Matthew Wilcox wrote:
> >
> >> I think you misunderstood. The right interface to call, that should
> >> work everywhere, should be the simple, obvious one. ioremap(). That
> >> effectively is what everyone gets anyway (since they test on x86).
> >> So change the *definition* of ioremap() to be uncached. Then we
> >> can add
> >> ioremap_wc() and ioremap_cached() for these special purpose mappings.
> >
> > That would break all the current users who do ioremap on memory
> > and want it cached.
>
> What's an example of this? I ask since on powerpc ioremap() is
> always _PAGE_NO_CACHE.

ACPI, IPMI, DMI, ... I bet there are more. It's needed every time
a driver needs to look for some firmware table because it might
not be mapped.

-Andi