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Date: Sun, 25 Aug 2019 00:34:49 +0200
From: Christoph Hellwig <hch@lst.de>
To: Paul Burton <paul.burton@mips.com>
Subject: Re: cleanup the dma_pgprot handling
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On Fri, Aug 23, 2019 at 09:58:04PM +0000, Paul Burton wrote:
> So I believe uncached & uncached accelerated are another case like that
> described above - they're 2 different CCAs but the same "access type",
> namely uncached.
> 
> Section 4.9 then goes on to forbid mixing access types, but not CCAs.
> 
> It would be nice if the precise mapping from CCA to access type was
> provided, but I don't see that anywhere. I can check with the
> architecture team to be sure, but to my knowledge we're fine to mix
> access via kseg1 (ie. uncached) & mappings with CCA=7 (uncached
> accelerated).

Ok.  Looks like we can keep it then and I'll add a comment to the
code with the above reference.