Re: [PATCH v2] staging: ion: Add a default struct device for cma heap

[Feng Tang]

On Fri, Aug 07, 2015 at 04:48:28PM +0200, Michal Nazarewicz wrote:
> On Fri, Aug 07 2015, Feng Tang wrote:
> > As I described above, the dummy struct device is only needed for
> > dma request, its lifetime is align with the cma_heap itself. 
> 
> Again, this is from perspective of someone who is unfamiliar with ION,
> but perhaps a viable solution is to bypass DMA API and just call
> cma_alloc directly?

For ion cma heap, the buffer allocation func ion_cma_allocate() will
call dma_alloc_coherent(dev, ...). And dma_alloc_coherent() is
implemented by each architeture(arm/m68k/x86 etc), and many Arch's
implementation doesn't use cma, but use alloc_pages() like APIs.
So I'm afraid we can't direcly call cma_alloc directly here.

Thanks,
Feng
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