From mboxrd@z Thu Jan 1 00:00:00 1970 From: mans@mansr.com (=?iso-8859-1?Q?M=E5ns_Rullg=E5rd?=) Date: Fri, 09 Dec 2016 17:28:01 +0000 Subject: Tearing down DMA transfer setup after DMA client has finished In-Reply-To: <20161209171727.GK6408@localhost> (Vinod Koul's message of "Fri, 9 Dec 2016 22:47:27 +0530") References: <5846B237.8060409@free.fr> <20161207164341.GX6408@localhost> <20161208103921.GC6408@localhost> <91b0d10c-1bc2-c3e1-4088-f4ad9adcd6c0@free.fr> <20161208163755.GH6408@localhost> <20161209065955.GJ6408@localhost> <6ce1ea97-1d68-2203-c7b4-73315e801655@laposte.net> <20161209171727.GK6408@localhost> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Vinod Koul writes: > On Fri, Dec 09, 2016 at 11:25:57AM +0100, Sebastian Frias wrote: >> >> What concrete solution do you propose? > > I have already proposed two solutions. > > A) Request a channel only when you need it. Obviously we can't do virtual > channels with this (though we should still use virt-channels framework). > The sbox setup and teardown can be done as part of channel request and > freeup. PL08x already does this. > > Downside is that we can only have as many consumers at a time as channels. > > I have not heard any technical reason for not doing this apart from drivers > grab the channel at probe, which is incorrect and needs to be fixed > irrespective of the problem at hand. > > This is my preferred option. Sorry, but this is not acceptable. > B) Create a custom driver specific API. This API for example: > sbox_setup(bool enable, ...) > can be called by client to explicitly setup and clear up the sbox setting. > > This way we can have transactions muxed. > > I have not heard any arguments on why we shouldn't do this except Russell's > comment that A) solves this. Driver-specific interfaces are not the solution. That way lies chaos and madness. This would all be so much easier if you all would just shut up for a moment and let me fix it properly. -- M?ns Rullg?rd