[RFC 0/3] How to pass IOMMU map attr via DMA API?

[Hiroshi Doyu]

On Fri, 21 Jun 2013 18:03:44 +0200
Joerg Roedel <joro at 8bytes.org> wrote:

> On Fri, Jun 21, 2013 at 09:17:59AM +0200, Marek Szyprowski wrote:
> > Using DMA attributes for this seems to be a bad idea. The dma direction
> > parameter is much more appropriate. Will Deacon recently posted a patch
> > which does it right, see:
> > 
> > https://git.linaro.org/gitweb?p=people/mszyprowski/linux-dma-mapping.git;a=commit;h=8fc3749bd31d139db58f874e093255fe62505968
> 
> Agreed, that is one usecase the dma-direction parameter was made for. In
> particular:
> 
> 	DMA_FROM_DEVICE		-> Write only mapping
> 	DMA_TO_DEVICE 		-> Read only mapping
> 	DMA_BIDIRECTIONAL	-> Read/Write mapping
> 
> So no need to use the dma attributes for that.

Ok, thanks. One more question, IOMMU H/W sometimes supports more
platform specific attributes than READ/WRITE. For example, in OMAP,

  #define IOMMU_FLAG	(IOVMF_ENDIAN_LITTLE | IOVMF_ELSZ_8)

Is there any way to deal with those platform specific attrs from DMA
mapping API POV?