From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Wed, 30 Jan 2013 10:08:30 +0000 Subject: [PATCH 1/5] dmaengine: dw_dmac: move to generic DMA binding In-Reply-To: References: <1359395857-1235-1-git-send-email-arnd@arndb.de> <201301300941.35886.arnd@arndb.de> Message-ID: <201301301008.31196.arnd@arndb.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wednesday 30 January 2013, Viresh Kumar wrote: > On Wed, Jan 30, 2013 at 3:11 PM, Arnd Bergmann wrote: > > On Wednesday 30 January 2013, Viresh Kumar wrote: > >> I knew you will come to this :) > >> So, the hardware is like: there are 16 request line slots per master, a > >> platform can choose to connect same or separate devices to these. > >> > >> So, these are really 16 per master. > > > > Ok, I see. Do you know how these are numbered in the data sheet? > > > > If the convention is to have subsequent numbers for these in the > > hardware description, we should probably just have that single > > request number in the binding, too, and calculate the master number > > from that. If it lists pairs of request/master number, we should > > use pairs in the binding as well, in the same order. > > Actually what would be better to have is: > - have this range from 0-15 only > - together with the master we want to use for peripheral > > this should be enough. Ok. > Datasheet of dw_dmac doesn't tell much about it.. just four bits for programming > it and so values are from 0-15 :) I meant the spear13xx data sheet, which has to list the request lines for its integrated components. There may be other SoCs using the same dw_dmac, but this is the main one that is upstream now, and it's probably as good as any other one. I just wouldn't want to establish a binding that doesn't match any of the known implementations in the way it expresses request lines. Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH 1/5] dmaengine: dw_dmac: move to generic DMA binding Date: Wed, 30 Jan 2013 10:08:30 +0000 Message-ID: <201301301008.31196.arnd@arndb.de> References: <1359395857-1235-1-git-send-email-arnd@arndb.de> <201301300941.35886.arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: "devicetree-discuss" To: Viresh Kumar Cc: Vinod Koul , devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, spear-devel , Andy Shevchenko , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org On Wednesday 30 January 2013, Viresh Kumar wrote: > On Wed, Jan 30, 2013 at 3:11 PM, Arnd Bergmann wrote: > > On Wednesday 30 January 2013, Viresh Kumar wrote: > >> I knew you will come to this :) > >> So, the hardware is like: there are 16 request line slots per master, a > >> platform can choose to connect same or separate devices to these. > >> > >> So, these are really 16 per master. > > > > Ok, I see. Do you know how these are numbered in the data sheet? > > > > If the convention is to have subsequent numbers for these in the > > hardware description, we should probably just have that single > > request number in the binding, too, and calculate the master number > > from that. If it lists pairs of request/master number, we should > > use pairs in the binding as well, in the same order. > > Actually what would be better to have is: > - have this range from 0-15 only > - together with the master we want to use for peripheral > > this should be enough. Ok. > Datasheet of dw_dmac doesn't tell much about it.. just four bits for programming > it and so values are from 0-15 :) I meant the spear13xx data sheet, which has to list the request lines for its integrated components. There may be other SoCs using the same dw_dmac, but this is the main one that is upstream now, and it's probably as good as any other one. I just wouldn't want to establish a binding that doesn't match any of the known implementations in the way it expresses request lines. Arnd