From mboxrd@z Thu Jan 1 00:00:00 1970 From: vinod.koul@intel.com (Vinod Koul) Date: Thu, 8 Dec 2016 16:07:30 +0530 Subject: Tearing down DMA transfer setup after DMA client has finished In-Reply-To: References: <58356EA8.2010806@free.fr> <20161125045549.GC2698@localhost> <092f44ee-4560-be17-25f7-00948dba3cfa@free.fr> <20fc9020-7278-bc2f-2a8d-43aff5cabff8@free.fr> <20161206051222.GQ6408@localhost> <5846B237.8060409@free.fr> <20161207164156.GW6408@localhost> Message-ID: <20161208103730.GB6408@localhost> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Dec 07, 2016 at 04:44:55PM +0000, M?ns Rullg?rd wrote: > Vinod Koul writes: > >> > >> What you're proposing, Vinod, is to make a channel exclusive > >> to a driver, as long as the driver has not explicitly released > >> the channel, via dma_release_channel(), right? > > > > Precisely, but yes the downside of that is concurrent access are > > limited, but am not sure if driver implements virtual channels and > > allows that.. > > My driver implements virtual channels. The problem is that the physical > dma channels signal completion slightly too soon, at least with > mem-to-device transfers. Apparently we need to keep the sbox routing > until the peripheral indicates that it has actually received all the > data. So do we need concurrent accesses by all clients. -- ~Vinod