From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759370Ab1IIQSp (ORCPT ); Fri, 9 Sep 2011 12:18:45 -0400 Received: from casper.infradead.org ([85.118.1.10]:37418 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758751Ab1IIQSo (ORCPT ); Fri, 9 Sep 2011 12:18:44 -0400 Subject: Re: [PATCH] dmaengine: add CSR SiRFprimaII DMAC driver From: Vinod Koul To: Arnd Bergmann Cc: vinod.koul@intel.com, Linus Walleij , Barry Song <21cnbao@gmail.com>, linux-kernel@vger.kernel.org, workgroup.linux@csr.com, Rongjun Ying , Barry Song , dan.j.williams@intel.com, linux-arm-kernel@lists.infradead.org In-Reply-To: <2264116.VTHb2BIH5a@wuerfel> References: <1315374075-15479-1-git-send-email-Baohua.Song@csr.com> <201109081819.30035.arnd@arndb.de> <2264116.VTHb2BIH5a@wuerfel> Content-Type: text/plain; charset="UTF-8" Organization: Intel Corp Date: Fri, 09 Sep 2011 21:40:59 +0530 Message-ID: <1315584659.28058.5.camel@vkoul-mobl4> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2011-09-08 at 22:11 +0200, Arnd Bergmann wrote: > On Thursday 08 September 2011 20:48:26 Linus Walleij wrote: > > 2011/9/8 Arnd Bergmann : > > > On Thursday 08 September 2011, Barry Song wrote: > > >> > > >> this filter is used by all drivers with DMA since every dma channel is > > >> fixed to be assigned to one device. > > > > > > Ok, I see now. I think it would be best to introduce a generic > > > 'filter by device tree property' function or alternatively an > > > dma_of_request_channel function like this: > > > > You'd have to discuss that with Vinod, the thing is that x86 Atom > > systems are using dmaengine for device slave transfers too, and > > IIRC these things don't use devicetrees. I may be wrong... > > Some of them use device tree, some don't. > > I'm not saying that we have to convert all drivers to use this, but > for platforms that always have device tree available, it seems by far > the cleanest solution. It maybe a clean solution but if it doesn't fit all needs, then it am not sure... One way as I said earlier to get the information of dmac-client relationships from arch specific way (pci, device tree etc) and dmacs/clients/platform presents them in arch-independent way to dmaengine... Thoughts? -- ~Vinod -- ~Vinod Koul Intel Corp.