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FromDavid Brownell <>
SubjectRe: [RFC v2 0/5] dmaengine: Slave DMA interface and example users
DateTue, 29 Jan 2008 22:56:14 -0800
On Tuesday 29 January 2008, Haavard Skinnemoen wrote:
>
> Btw, there's one issue I forgot to mention: I believe the DMA Engine
> framework is currently misusing the DMA mapping API, and this patchset
> makes things worse.
>
> Currently, the async_tx bits of the API do the required calls to
> dma_map_single() and/or dma_map_page(), but they rely on the driver to
> do the unmapping. This is problematic ...
>
> How do we solve this?

How about: for peripheral DMA, don't let the engine see anything
except dma_addr_t values.

The engine needs to be able to dma_alloc_coherent() memory too,
which is pre-mapped.

- Dave


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