From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031202Ab2CSNib (ORCPT ); Mon, 19 Mar 2012 09:38:31 -0400 Received: from moutng.kundenserver.de ([212.227.126.171]:57199 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030816Ab2CSNi3 (ORCPT ); Mon, 19 Mar 2012 09:38:29 -0400 Date: Mon, 19 Mar 2012 14:38:27 +0100 (CET) From: Guennadi Liakhovetski X-X-Sender: lyakh@axis700.grange To: Vinod Koul cc: Russell King - ARM Linux , linux-kernel@vger.kernel.org, "'Jassi Brar'" , Linus Walleij , Magnus Damm , Paul Mundt Subject: Re: [PATCH/RFC] dmaengine: add a slave parameter to __dma_request_channel() In-Reply-To: <1332164062.7180.19.camel@vkoul-udesk3> Message-ID: References: <1331101687.24656.319.camel@vkoul-udesk3> <20120307093026.GM17370@n2100.arm.linux.org.uk> <20120307103112.GP17370@n2100.arm.linux.org.uk> <20120307124620.GT17370@n2100.arm.linux.org.uk> <20120307142634.GA18787@n2100.arm.linux.org.uk> <20120307162755.GB18787@n2100.arm.linux.org.uk> <1331188201.4657.51.camel@vkoul-udesk3> <1331204128.4657.54.camel@vkoul-udesk3> <1331206459.4657.59.camel@vkoul-udesk3> <1331211513.4657.67.camel@vkoul-udesk3> <1331284918.4657.69.camel@vkoul-udesk3> <1331285959.4657.76.camel@vkoul-udesk3> <1331520476.4657.79.camel@vkoul-udesk3> <1332157021.7180.5.camel@vkoul-udesk3> <1332164062.7180.19.camel@vkoul-udesk3> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Provags-ID: V02:K0:kfVTc4PbYvt3zUMFKiz3RnWoXB0UDT1E25xo5HZvn0m 21RwZ/UMpT4fGP7C8KpAwpW81V46Z2p3/sdoomGIEtGKbt/o/j qGHkzj7BRThY9aFZfDoLNLPopt4jwX6FIW7cb/LEhhF4RC1Kit tgYL5/eurSzzrFz6CNQLP5r+L4Bj0VnMei3T/wNDBJ6kzwOu/k BdSjqY2cmTmaAIEBTj/nyisJt35not02lUHd/rN0Sj15JZHWUH xFW3z/du33J3aYi+G6YOvX78vX8Bc6tMtRsFWNO7Im2U7/NbcI ewrg2Ig18foq93wkuKoeHieqRsideh6Qz6FnvuNuIJZeeuqpXG hwdlWljkaWcHoHyUdtjQswMuNiI1XjYnSpc4vcZ5lzlfMPSzpX /fFTzF+A7rjPw== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 19 Mar 2012, Vinod Koul wrote: > On Mon, 2012-03-19 at 12:47 +0100, Guennadi Liakhovetski wrote: > > As I wrote in a reply to Linus W - you need to pass information about the > > requesting client to the dmaengine core to let it match it against mapping > > tables. > NO. > The client only needs to say that he needs a channel for DMA_SLAVE How? dma_request_channel(mask, filter_fn, filter_arg) Where shall the client pass to dmaengine its identity info? > DMAengine will know for this client, the platform channel map (already > given to it by platform) says that we can give it DMAC X, channel 4 > only. Some clients need multiple channels - Tx, Rx,... Thanks Guennadi > So see if it free, if so allocate it and give to client (while > doing usual stuff) > > You have to pass this information with the dma_request_channel() > > function. So, either you need to add a parameter or you have to reuse one > > of existing ones, e.g., deprecate the filter and use its argument for this > > purpose. If you do this and as long as you pass that parameter further on > > to the dmaengine device (controller) driver after whatever matching you > > like to do in the core - I'm fine with that, that fits well with my > > initial proposal. > I don't care about filter, it can go away if it is not required. > > Passing slave_config is *enhancement* so for (hopefully) last time > a) it has *nothing* to do with getting a channel, no role to play in > generic scheme of things > b) it allows client to call one api for get+configure thats all! > > -- > ~Vinod > --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/