From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vinod Koul Date: Mon, 16 Jul 2012 06:57:35 +0000 Subject: Re: [PATCH 5/7 v2] dma: sh: use an integer slave ID to improve API compatibility Message-Id: <1342421587.1726.49.camel@vkoul-udesk3> List-Id: References: <1341484183-10757-1-git-send-email-g.liakhovetski@gmx.de> <1341484183-10757-6-git-send-email-g.liakhovetski@gmx.de> <1342418828.1726.37.camel@vkoul-udesk3> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Guennadi Liakhovetski Cc: Magnus Damm , linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org On Mon, 2012-07-16 at 08:37 +0200, Guennadi Liakhovetski wrote: > On Mon, 16 Jul 2012, Vinod Koul wrote: > > > On Thu, 2012-07-05 at 12:29 +0200, Guennadi Liakhovetski wrote: > > > diff --git a/include/linux/sh_dma.h b/include/linux/sh_dma.h > > > index a79f10a..4e83f3e 100644 > > > --- a/include/linux/sh_dma.h > > > +++ b/include/linux/sh_dma.h > > > @@ -27,10 +27,10 @@ struct sh_dmae_slave { > > > * a certain peripheral > > > */ > > > struct sh_dmae_slave_config { > > > - unsigned int slave_id; > > > - dma_addr_t addr; > > > - u32 chcr; > > > - char mid_rid; > > > + int slave_id; > > > + dma_addr_t addr; > > > + u32 chcr; > > > + char mid_rid; > > > }; > > why would you want to keep your own slave_id and addr fields when they > > are already provided in struct dma_slave_config. > > Modifying the driver's API would break all its clients. rightly so, they need to be moved too. > > > Also while at it, what > > would be the use of last tow fields, what do they describe? > > They tell the driver how the channel has to be configured to support this > specific client. They are values of two specific registers. In fact, CHCR > means exactly that - CHannel Control Register. what exactly does the channel control register do in shdma? Should shdma driver deduce this value rather than client giving it? Same question for mid_rid? -- ~Vinod From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751808Ab2GPGxU (ORCPT ); Mon, 16 Jul 2012 02:53:20 -0400 Received: from mga01.intel.com ([192.55.52.88]:61045 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750769Ab2GPGxT (ORCPT ); Mon, 16 Jul 2012 02:53:19 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="193257148" Subject: Re: [PATCH 5/7 v2] dma: sh: use an integer slave ID to improve API compatibility From: Vinod Koul To: Guennadi Liakhovetski Cc: Magnus Damm , linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: References: <1341484183-10757-1-git-send-email-g.liakhovetski@gmx.de> <1341484183-10757-6-git-send-email-g.liakhovetski@gmx.de> <1342418828.1726.37.camel@vkoul-udesk3> Content-Type: text/plain; charset="UTF-8" Date: Mon, 16 Jul 2012 12:23:07 +0530 Message-ID: <1342421587.1726.49.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, 2012-07-16 at 08:37 +0200, Guennadi Liakhovetski wrote: > On Mon, 16 Jul 2012, Vinod Koul wrote: > > > On Thu, 2012-07-05 at 12:29 +0200, Guennadi Liakhovetski wrote: > > > diff --git a/include/linux/sh_dma.h b/include/linux/sh_dma.h > > > index a79f10a..4e83f3e 100644 > > > --- a/include/linux/sh_dma.h > > > +++ b/include/linux/sh_dma.h > > > @@ -27,10 +27,10 @@ struct sh_dmae_slave { > > > * a certain peripheral > > > */ > > > struct sh_dmae_slave_config { > > > - unsigned int slave_id; > > > - dma_addr_t addr; > > > - u32 chcr; > > > - char mid_rid; > > > + int slave_id; > > > + dma_addr_t addr; > > > + u32 chcr; > > > + char mid_rid; > > > }; > > why would you want to keep your own slave_id and addr fields when they > > are already provided in struct dma_slave_config. > > Modifying the driver's API would break all its clients. rightly so, they need to be moved too. > > > Also while at it, what > > would be the use of last tow fields, what do they describe? > > They tell the driver how the channel has to be configured to support this > specific client. They are values of two specific registers. In fact, CHCR > means exactly that - CHannel Control Register. what exactly does the channel control register do in shdma? Should shdma driver deduce this value rather than client giving it? Same question for mid_rid? -- ~Vinod