Messages in this thread | | | Date | Tue, 19 Aug 2014 20:27:34 +0530 | From | Vinod Koul <> | Subject | Re: [PATCH] Documentation: dmaengine: Add a documentation for the dma controller API |
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On Tue, Aug 19, 2014 at 03:44:23PM +0100, Russell King - ARM Linux wrote: > On Tue, Aug 19, 2014 at 07:15:07PM +0530, Vinod Koul wrote: > > On Thu, Aug 14, 2014 at 09:57:53AM +0100, Russell King - ARM Linux wrote: > > > It's got something to do with the async engine API, and seems to be > > > something to do with whether a descriptor can have other transactions > > > added to it, and whether a descriptor can be re-used (async-tx engines > > > typically allocate a fixed set of descriptors and recycle them.) > > Yes this is my understanding too. Async API IIUC can reuse descriptors and > > if engine doesnt support this is a way to tell them please do use that. > > > > For slave dmanegine API we need to ignore it. > > We shouldn't ignore it - ignoring it makes it harder to implement a DMA > engine driver which supports both the slave and async APIs, because > we then need to know the reason for the channel being requested. Do you have such usage coming up near future :) > > Ignoring it until it can be understood and documented is an approach I > would agree with though. Certainly, I am asking Dan to add more clarity on these bits to help improve.
-- ~Vinod
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