[Linaro-mm-sig] [RFC] ARM: dma_map|unmap_sg plus iommu
Ramirez Luna, Omar
omar.ramirez at ti.com
Mon Aug 8 15:21:46 UTC 2011
On Sun, Jul 31, 2011 at 7:57 PM, KyongHo Cho <pullip.cho at samsung.com> wrote:
> On Fri, Jul 29, 2011 at 11:24 PM, Marek Szyprowski
>> Right now I have no idea how to handle this better. Perhaps with should be
>> to specify somehow the target dma_address when doing memory allocation, but I'm
>> really convinced yet if this is really required.
> What about using 'dma_handle' argument of alloc_coherent callback of
> Although it is an output argument, I think we can convey a hint or
> start address to map
> to the IO memory manager that resides behind dma API.
I also thought on this one, even dma_map_single receives a void *ptr
which could be casted into a struct with both physical and virtual
addresses to be mapped, but IMHO, this starts to add twists into the
dma map parameters which might create confusion.
> DMA API is so abstract that it cannot cover all requirements by
> various device drivers;;
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