From: Andi Kleen <ak@suse.de>
To: Kumar Gala <galak@kernel.crashing.org>
Subject: Re: [PATCH] ioremap_cached()
Date: Thu, 30 Mar 2006 22:27:53 +0200
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Cc: Matthew Wilcox <matthew@wil.cx>, linux-kernel@vger.kernel.org
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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
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