[PATCH 2/2] ARM: use cached memory in dma_alloc_coherent() if possible

Catalin Marinas
2010-12-21T11:11:21Z

On Tuesday, 21 December 2010, Russell King - ARM Linux
<linux@arm.linux.org.uk> wrote:
> On Tue, Dec 21, 2010 at 10:20:02AM +0000, Jamie Iles wrote:
>> For fully coherent architectures or systems using the ARM ACP to provide
>> coherency to individual device, use cached memory as the coherent
>> backing rather than noncached or simply bufferable memory.
>
> As has already been covered by Catalin, as far as we know, no one uses
> the ACP yet. ?Do you have a system which does?

I'm not sure there is any publicly available system yet. This may be
present in future systems, though only a few peripherals would
probably be connected to the ACP (like an HD LCD controller). So I
don't think we'll get a completely coherent system and a better
approach may be to add per-device DMA operations.

--
Catalin