From mboxrd@z Thu Jan 1 00:00:00 1970 From: viresh.kumar@st.com (Viresh Kumar) Date: Fri, 26 Aug 2011 09:11:02 +0530 Subject: [PATCH 16/18] dmaengine/amba-pl08x: Add support for sg len greater than one for slave transfers In-Reply-To: <4E532B19.6000103@st.com> References: <5d691ab0c4f447c9f324213d8d740ac61d1739a1.1311936524.git.viresh.kumar@st.com> <20110814083618.GE4986@n2100.arm.linux.org.uk> <4E4CCF7B.8060704@st.com> <20110821083306.GA12028@n2100.arm.linux.org.uk> <4E532B19.6000103@st.com> Message-ID: <4E5715CE.2070806@st.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 8/23/2011 9:52 AM, Viresh Kumar wrote: > On 8/21/2011 2:03 PM, Russell King - ARM Linux wrote: >>>> I am not sure if i get this completely. In memcpy, we still don't support >>>> more than one sg. We have created a new member in txd, which keeps track of >>>> data (addresses, len). >> Yes, but we shouldn't need to translate it into any kind of scatterlist. >> > > Ok. I way out is keeping two separate variables in txd, list for slave transfers, > and pointer to single element for memcpy. And that looks to be even bad to me. > Why waste memory, for second variable. Or create union of both. > > One more thing, we can actually have scatter gather in memcpy too in future. This will be > helpful then also. But surely that's something not implemented currently. > Russell/Linus, Probably this is the only issue left in this patch. (Sorry if i missed some other points) Please suggest what should i modify here, so that Vinod can go ahead and push pending patches too. -- viresh From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752544Ab1HZDlw (ORCPT ); Thu, 25 Aug 2011 23:41:52 -0400 Received: from eu1sys200aog109.obsmtp.com ([207.126.144.127]:36465 "EHLO eu1sys200aog109.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751243Ab1HZDls (ORCPT ); Thu, 25 Aug 2011 23:41:48 -0400 Message-ID: <4E5715CE.2070806@st.com> Date: Fri, 26 Aug 2011 09:11:02 +0530 From: Viresh Kumar User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:6.0) Gecko/20110812 Thunderbird/6.0 MIME-Version: 1.0 To: Russell King - ARM Linux , "linus.walleij@linaro.org" Cc: Pratyush ANAND , Rajeev KUMAR , Bhupesh SHARMA , Shiraz HASHIM , "vinod.koul@intel.com" , "linux-kernel@vger.kernel.org" , Vipin KUMAR , Armando VISCONTI , Amit VIRDI , Vipul Kumar SAMAR , "viresh.linux@gmail.com" , Deepak SIKRI , "dan.j.williams@intel.com" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH 16/18] dmaengine/amba-pl08x: Add support for sg len greater than one for slave transfers References: <5d691ab0c4f447c9f324213d8d740ac61d1739a1.1311936524.git.viresh.kumar@st.com> <20110814083618.GE4986@n2100.arm.linux.org.uk> <4E4CCF7B.8060704@st.com> <20110821083306.GA12028@n2100.arm.linux.org.uk> <4E532B19.6000103@st.com> In-Reply-To: <4E532B19.6000103@st.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/23/2011 9:52 AM, Viresh Kumar wrote: > On 8/21/2011 2:03 PM, Russell King - ARM Linux wrote: >>>> I am not sure if i get this completely. In memcpy, we still don't support >>>> more than one sg. We have created a new member in txd, which keeps track of >>>> data (addresses, len). >> Yes, but we shouldn't need to translate it into any kind of scatterlist. >> > > Ok. I way out is keeping two separate variables in txd, list for slave transfers, > and pointer to single element for memcpy. And that looks to be even bad to me. > Why waste memory, for second variable. Or create union of both. > > One more thing, we can actually have scatter gather in memcpy too in future. This will be > helpful then also. But surely that's something not implemented currently. > Russell/Linus, Probably this is the only issue left in this patch. (Sorry if i missed some other points) Please suggest what should i modify here, so that Vinod can go ahead and push pending patches too. -- viresh