From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031329Ab2CSOSA (ORCPT ); Mon, 19 Mar 2012 10:18:00 -0400 Received: from mga09.intel.com ([134.134.136.24]:61345 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030558Ab2CSOR7 (ORCPT ); Mon, 19 Mar 2012 10:17:59 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.67,352,1309762800"; d="scan'208";a="119126633" Subject: Re: [PATCH/RFC] dmaengine: add a slave parameter to __dma_request_channel() From: Vinod Koul To: Guennadi Liakhovetski Cc: Russell King - ARM Linux , linux-kernel@vger.kernel.org, "'Jassi Brar'" , Linus Walleij , Magnus Damm , Paul Mundt In-Reply-To: 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> <1332165604.7180.24.camel@vkoul-udesk3> Content-Type: text/plain; charset="UTF-8" Date: Mon, 19 Mar 2012 19:52:18 +0530 Message-ID: <1332166938.7180.38.camel@vkoul-udesk3> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2012-03-19 at 15:09 +0100, Guennadi Liakhovetski wrote: > YES! This is exactly what I am talking about! We need an additional > parameter to dma_request_channel(). Whereas in the discussion, that you > pointed me to, it still had the same 3 parameters, as now. (Maybe this has > already been decided upon before - to add an additional parameter, not > sure anymore, this thread has become too long and too slow... My apologies > in this case) So, this can be a device pointer or some specialised slave > ID. Device pointer is nice, I agree. And the next change, that I'd like to > request is pass this parameter further on to DMA device driver's > .device_alloc_chan_resources() method. Sorry my bad. I confused your request for additional parameter as request for adding slave_config etc stuff into request API. Yes this API would need to be modified for telling dmaengine about client. Now Given that this is more slave stuff, I have leaning to adding a slave specific request api, something like dmaengine_request_slave_channel() which is used for our purpose while keeping the original API intact for async_tx usages. Btw why should .device_alloc_chan_resources() need this, I so no reason, unless we are working around some other issue. -- ~Vinod