Messages in this thread | | | Date | Tue, 26 Jan 2010 12:11:34 -0800 | From | Abhijeet Dharmapurikar <> | Subject | Re: [RFC PATCH] dma: Add barrierless dma mapping/unmapping api |
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FUJITA Tomonori wrote: > On Tue, 26 Jan 2010 15:30:10 +1100 > Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote: > >> On Mon, 2010-01-25 at 18:35 -0800, adharmap@codeaurora.org wrote: >>> From: Abhijeet Dharmapurikar <adharmap@quicinc.com> >>> > >> There are people nowadays putting AXI bridges and the whole ARM >> paraphernalia of IP cores behind them on PowerPC cores for example and I >> can see that happening with x86 as well. >> >> In your case, I believe your are fixing the wrong problem anyways. The >> right approach would be instead to put all your buffer into an sglist >> and use dma_map/unmap_sg(). > > Agreed again. That's exactly what I suggested before: > > http://marc.info/?l=linux-kernel&m=126294076917753&w=2
I somehow missed your post, my apologies. Agreed that dma_map/unmap_sg would be the correct api to use here, however they still call the dmac_.*_range to map buffers. I could change those calls to do a barrier only after mapping the last buffer. This would be much more cleaner than introducing a .*_nobarrier API.
Thanks for all the replies.
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