Messages in this thread | | | Date | Fri, 8 Jan 2010 17:52:20 +0900 | Subject | Re: RFC non barrier versions of dma_map functions | From | FUJITA Tomonori <> |
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On Mon, 04 Jan 2010 15:28:33 -0800 Abhijeet Dharmapurikar <adharmap@codeaurora.org> wrote:
> This is a request for extending the DMA api for efficient handling of > multiple buffers or scatter gather mapping/unmapping operations. > > I am based on an ARMv7 device and we have a situation where we need > to dma map multiple cached buffers for a single dma transaction. > > The current DMA api suggests the use of dma_map_single/ > dma_unmap_single for cache consistency. On ARMv7 it performs the > necessary cache-operations and calls data sync barrier instruction > (DSB). In our case we would be executing multiple DSB instructions > before starting the dma operation - we need memory to be consistent > only after we map the last buffer.
dma_map_sg? dma_map_sg requires the buffers to be consistent only after it maps the last buffer, I think (I guess that you mean 'consistent' buffer is 'DMA ready' wrt cache).
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