Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752326Ab1EIGTv (ORCPT ); Mon, 9 May 2011 02:19:51 -0400 Received: from mga14.intel.com ([143.182.124.37]:56149 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751810Ab1EIGTu (ORCPT ); Mon, 9 May 2011 02:19:50 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.64,338,1301900400"; d="scan'208";a="432768432" Subject: Re: [PATCH V4 3/5] dmaengine/dw_dmac: Divide one sg to many desc, if sg len is greater than DWC_MAX_COUNT From: "Koul, Vinod" To: viresh kumar Cc: "dan.j.williams@intel.com" , "linux-kernel@vger.kernel.org" , Armando VISCONTI , Shiraz HASHIM , "linux-arm-kernel@lists.infradead.org" , "viresh.linux@gmail.com" , "linux@arm.linux.org.uk" In-Reply-To: <4DC783A9.5060802@st.com> References: <1304918425.32447.20.camel@vkoul-udesk3> <4DC783A9.5060802@st.com> Content-Type: text/plain; charset="UTF-8" Date: Mon, 09 May 2011 11:17:21 +0530 Message-ID: <1304920041.32447.33.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 Content-Length: 1531 Lines: 39 On Mon, 2011-05-09 at 11:33 +0530, viresh kumar wrote: > On 05/09/2011 10:50 AM, Koul, Vinod wrote: > >> > @@ -695,9 +695,15 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, > >> > reg = dws->tx_reg; > >> > for_each_sg(sgl, sg, sg_len, i) { > >> > struct dw_desc *desc; > >> > - u32 len; > >> > - u32 mem; > >> > + u32 len, dlen, mem; > >> > > >> > + mem = sg_phys(sg); > >> > + len = sg_dma_len(sg); > >> > + mem_width = 2; > > hardcoding mem_width doesn't make sense, you should take this from input > > params > > Firstly, this change is not introduced in this patch, i have just rearranged this. > So, will send separate patch if this change is required. > > Secondly, peripheral width is taken from chan->private. And by 2 for mem_width, > we meant word-by-word here. Shouldn't we always try word-by-word here? > How should we pass width for memory? Ah, then there is another todo for this driver. Move from chan->private to DMA_SLAVE_CONFIG. struct dma_slave_config has dedicated fields for both source and destination widths, src_addr_width & dst_addr_width please use them... You should pass this structure to device control API as: dmaengine_device_control( chan, DMA_SLAVE_CONFIG, (unsigned long)&slave_config); -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/