[PATCH 4/5] arm64: dma-mapping: Only swizzle DMA ops for IOMMU_DOMAIN_DMA

On Thu, Jan 19, 2017 at 07:00:25PM +0000, Robin Murphy wrote:

On 19/01/17 18:19, Will Deacon wrote:

quoted

The arm64 DMA-mapping implementation sets the DMA ops to the IOMMU DMA
ops if we detect that an IOMMU is present for the master and the DMA
ranges are valid.

In the case when the IOMMU domain for the device is not of type
IOMMU_DOMAIN_DMA, then we have no business swizzling the ops, since
we're not in control of the underlying address space. This patch leaves
the DMA ops alone for masters attached to non-DMA IOMMU domains.

In fact, I don't think there would be any harm in taking this one
through arm64 straight away. The DMA ops can't be expected to work
successfully on any old domain, so it's a reasonable sanity check
regardless.

Reviewed-by: Robin Murphy <robin.murphy@arm.com>

Good point; I'll queue this one for 4.11 via arm64.

Will