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* Coherent DMA mapping for existing struct page
@ 2011-01-24 20:26 Nikolaus Rath
  2011-01-25  1:28 ` Robert Hancock
  0 siblings, 1 reply; 2+ messages in thread
From: Nikolaus Rath @ 2011-01-24 20:26 UTC (permalink / raw)
  To: linux-kernel

Hello,

How do I set up a coherent DMA mapping for an existing struct page?
dma_alloc_coherent() wants to allocate its own buffer, and
dma_map_page() sets up streaming mappings. Which function am I missing?


Thanks,

   -Nikolaus

-- 
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^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: Coherent DMA mapping for existing struct page
  2011-01-24 20:26 Coherent DMA mapping for existing struct page Nikolaus Rath
@ 2011-01-25  1:28 ` Robert Hancock
  0 siblings, 0 replies; 2+ messages in thread
From: Robert Hancock @ 2011-01-25  1:28 UTC (permalink / raw)
  To: linux-kernel

On 01/24/2011 02:26 PM, Nikolaus Rath wrote:
> Hello,
>
> How do I set up a coherent DMA mapping for an existing struct page?
> dma_alloc_coherent() wants to allocate its own buffer, and
> dma_map_page() sets up streaming mappings. Which function am I missing?

I don't think you can do this. On some platforms, only certain memory 
can be used for coherent DMA, so you can't just use any arbitrary page.

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2011-01-24 20:26 Coherent DMA mapping for existing struct page Nikolaus Rath
2011-01-25  1:28 ` Robert Hancock

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