From mboxrd@z Thu Jan 1 00:00:00 1970 From: robherring2@gmail.com (Rob Herring) Date: Fri, 24 Aug 2012 08:05:50 -0500 Subject: Cortex A9 with ACP needing mixed coherency model In-Reply-To: <20120824085440.GC5400@mudshark.cambridge.arm.com> References: <20120824085440.GC5400@mudshark.cambridge.arm.com> Message-ID: <50377C2E.4080408@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 08/24/2012 03:54 AM, Will Deacon wrote: > 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. It's queued up in Marek's dma-mapping tree for 3.7. Rob