From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vinod Koul Date: Mon, 16 Jul 2012 08:40:25 +0000 Subject: Re: [PATCH 5/7 v2] dma: sh: use an integer slave ID to improve API compatibility Message-Id: <1342427305.1726.50.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> <1342421587.1726.49.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 09:13 +0200, Guennadi Liakhovetski wrote: > > > 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? > > See, e.g., > arch/arm/mach-shmobile/setup-sh7372.c::sh7372_dmae_slaves[]. > Platforms are supplying these values with shdma driver platform data, > together with slave IDs. Them when slaves request channels and supply > their slave IDs, the driver searches the above array, looking for the > matching slave ID, then it uses the rest of the information in those > structs to configure the channel for this client. Again, this is > nothing > new, this is how the driver has been functioning since a long time, > this > driver is not modifying anything there. Any changes to this > procedure, > like providing all thig information from clients themselves instead > of > keeping it with DMACs, requires these patches to be committed first. That wasn't my question. I want to know what does ccr and mid_rid mean to dmac here? -- ~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 S1752892Ab2GPI2k (ORCPT ); Mon, 16 Jul 2012 04:28:40 -0400 Received: from mga14.intel.com ([143.182.124.37]:45301 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752401Ab2GPI2g (ORCPT ); Mon, 16 Jul 2012 04:28:36 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="168807161" 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> <1342421587.1726.49.camel@vkoul-udesk3> Content-Type: text/plain; charset="UTF-8" Date: Mon, 16 Jul 2012 13:58:25 +0530 Message-ID: <1342427305.1726.50.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 09:13 +0200, Guennadi Liakhovetski wrote: > > > 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? > > See, e.g., > arch/arm/mach-shmobile/setup-sh7372.c::sh7372_dmae_slaves[]. > Platforms are supplying these values with shdma driver platform data, > together with slave IDs. Them when slaves request channels and supply > their slave IDs, the driver searches the above array, looking for the > matching slave ID, then it uses the rest of the information in those > structs to configure the channel for this client. Again, this is > nothing > new, this is how the driver has been functioning since a long time, > this > driver is not modifying anything there. Any changes to this > procedure, > like providing all thig information from clients themselves instead > of > keeping it with DMACs, requires these patches to be committed first. That wasn't my question. I want to know what does ccr and mid_rid mean to dmac here? -- ~Vinod