From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH 1/4] dt-bindings: Document the STM32 DMA bindings Date: Thu, 08 Oct 2015 22:40:19 +0200 Message-ID: <11583587.xphxbMQ7TN@wuerfel> References: <1444317612-818-1-git-send-email-cedric.madianga@gmail.com> <15651913.U8kb3JZ9vO@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: M'boumba Cedric Madianga Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Maxime Coquelin , robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, pawel.moll-5wv7dgnIgG8@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org, Kumar Gala , linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org, vinod.koul-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org On Thursday 08 October 2015 22:25:50 M'boumba Cedric Madianga wrote: > > > > How do you know which channels are available for memory-to-memory > > transfers? > For memory-to-memory transfer we don't need any channel/request combination. > We look for any available channel in the channel list to execute our transfer. > So, as often as possible, we expect that a peripheral release his > channel after transfering data. > In that way, we always should have at least one channel available for > that kind of transfer. > Ah, got it. So the use of virtual channels in this driver makes MEM2MEM transfers work, but is otherwise not required. Thanks for the clarification. Arnd -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html