Re: DMA mapping API(IOMMU) for ARM64?

[Catalin Marinas <catalin.marinas@arm.com>]

On Tue, Jun 18, 2013 at 11:32:44AM +0100, Arnd Bergmann wrote:
> On Tuesday 18 June 2013 11:19:14 Will Deacon wrote:
> > I've spoken briefly with Catalin about this and it seems like there might be
> > *some* scope for sharing common dma-mapping code between architectures.
> > There doesn't really need to be any architecture-specific details in
> > allocating iova space and the interface to the iommu drivers is
> > well-defined. The arch-specific stuff is bogged down in the non-coherent
> > buffer management, but that doesn't necessarily equate to lots of code.
> > 
> > So, the best bet would be to figure out how to split up what we have under
> > arch/arm/ so that it can be re-used by arm64 and potentially other
> > architectures (powerpc has some simple stuff for coherent mappings and some
> > less-simple stuff for non-coherent buffers).
> 
> I'm sure that other architectures are interested in sharing the code.
> Best move it into the global mm/ directory, at least the version for
> coherent mappings.

Or we could extend the lib/iommu-helper.c or add another file in there
(we already have lib/swiotlb.c).

-- 
Catalin