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From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: Cortex A9 with ACP needing mixed coherency model
Date: Fri, 24 Aug 2012 09:54:41 +0100	[thread overview]
Message-ID: <20120824085440.GC5400@mudshark.cambridge.arm.com> (raw)
In-Reply-To: <CAB9O=CPx2PKjyWiKa6B+MJnO0G=805Gb_rnjULb+xw1YOZjCyQ@mail.gmail.com>

On Fri, Aug 24, 2012 at 01:58:50AM +0100, John Linn wrote:
> It doesn't look like there's any good way to have a mixed coherency
> model to support using the ACP where there is coherency and using
> other ports where there is not coherency.
> ARM Linux kernel can support arch_is_coherent(), which means all DMA
> I/O is coherent. We have multiple DMA engines and they can go to thru
> coherent or non-coherent ports.
> 
> Am I missing something, or has someone figured out a way to deal with this?

Didn't Rob have a crack at fixing this with his recent DMA series?

  http://lists.infradead.org/pipermail/linux-arm-kernel/2012-August/113929.html

It's a really nice set of patches, so take a look.

Will

  reply	other threads:[~2012-08-24  8:54 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-24  0:58 Cortex A9 with ACP needing mixed coherency model John Linn
2012-08-24  8:54 ` Will Deacon [this message]
2012-08-24 13:05   ` Rob Herring

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