dma-mapping: support for DMA_ATTR_NON_CONSISTENT DMA attribute

Russell King - ARM Linux linux at
Mon Jun 29 03:08:04 PDT 2015

On Mon, Jun 29, 2015 at 12:05:09PM +0200, Sylvain Munaut wrote:
> Well that can't be since the dma_sync_* are part of streaming API and
> the dma_alloc_attrs is part of the "coherent" API (even though you
> have the NON_COHERENT flag in it ... that's a bit weird).
> But I don't see the alternative, unless the doc is suggesting I
> basically do all the cache invalidation myself manually and doing arch
> specific stuff directly in the driver ?

Maybe someone with this problem should work on a solution - augmenting
the coherent API with a set of functions to do what you want?

Please, if you find something lacking like this, make a proposal and
send a patch - but bear in mind that such an extension is not a matter
for just ARM, but every other architecture that the kernel supports,
so merely sending it to ARM mailing lists isn't going to get you very

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