Re: [PATCH v2 2/4] ARC: allow to use IOC and non-IOC DMA devices simultaneously

From: hch@xxxxxx
Date: Thu Aug 23 2018 - 10:03:35 EST

Btw, given that I assume this is 4.20 material now, any chance we
could merge it through the dma-mapping tree? I have some major changes
pending that would clash if done in a different tree, so I'd rather
get it all together.

> We check this flag in arch_dma_alloc (which are used in non-coherent case) to
> skip MMU mapping if we are advertised that consistency is not required.
> So, actually we can get rid of this flag checking in arch_dma_alloc and
> simply always do MMU mapping to enforce non-cachability and return
> non-cacheable memory even if DMA_ATTR_NON_CONSISTENT is passed.
> But I don't sure we want to do that.

I plan to kill this flag for 4.20 (or 4.20 at latest) in favor
of a better interface. But your implementation looks ok, so I'm
fine with keeping it for now.