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Date: Mon, 24 Jan 2011 19:28:07 -0600
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To: linux-kernel@vger.kernel.org
Subject: Re: Coherent DMA mapping for existing struct page
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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.