From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757753Ab1IHBVm (ORCPT ); Wed, 7 Sep 2011 21:21:42 -0400 Received: from linux-sh.org ([111.68.239.195]:56009 "EHLO linux-sh.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757718Ab1IHBVl (ORCPT ); Wed, 7 Sep 2011 21:21:41 -0400 Date: Thu, 8 Sep 2011 10:21:20 +0900 From: Paul Mundt To: "Koul, Vinod" Cc: "g.liakhovetski@gmx.de" , "Williams, Dan J" , "magnus.damm@gmail.com" , "linux-sh@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "damm@opensource.se" Subject: Re: [PATCH] serial: sh-sci: don't filter on DMA device, use only channel ID Message-ID: <20110908012119.GJ22142@linux-sh.org> References: <1315228408.26251.75.camel@vkoul-udesk3> <1315233788.26251.163.camel@vkoul-udesk3> <1315235335.26251.194.camel@vkoul-udesk3> <438BB0150E931F4B9CE701519A4463010871804A4B@bgsmsx502.gar.corp.intel.com> <438BB0150E931F4B9CE701519A4463010871804A4F@bgsmsx502.gar.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <438BB0150E931F4B9CE701519A4463010871804A4F@bgsmsx502.gar.corp.intel.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 08, 2011 at 03:07:53AM +0530, Koul, Vinod wrote: > On Wed, 2011-09-07 at 22:01 +0200, Guennadi Liakhovetski wrote: > > On Thu, 8 Sep 2011, Koul, Vinod wrote: > > You're seriously suggesting to export and use an additional shdma private > > function, bypassing the dmaengine API?... That really doesn't sound like a > > good idea to me, sorry. How about using .device_control(DMA_SLAVE_CONFIG) > > from the filter function directly to verify channel suitability? > Yes see stedma40, coh90138 drivers > .device_control is not right place as channel is already allocated. > No, that's not going to happen either. Many of these drivers are used in different CPUs with different DMACs. The dmaengine driver in question only applies to a subset, so the driver bits need to be wholly generic. In short, if the dmaengine API can't handle this sort of stuff then it's the dmaengine API that needs to be extended, we won't be working around dmaengine shortcomings in drivers that simply want a sensible DMA API to plug in to.