Re: Coherent DMA mapping for existing struct page

From: Robert Hancock
Date: Mon Jan 24 2011 - 20:28:14 EST


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.
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