From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933035AbcIFMDu (ORCPT ); Tue, 6 Sep 2016 08:03:50 -0400 Received: from mail-lf0-f54.google.com ([209.85.215.54]:34478 "EHLO mail-lf0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753949AbcIFMDs (ORCPT ); Tue, 6 Sep 2016 08:03:48 -0400 Subject: Re: [PATCH v2 0/2] Add memcpy support for tegra210-adma To: Jon Hunter , Nicolin Chen , vinod.koul@intel.com References: <319ca097-4b10-83b9-841c-52adccbb48ad@nvidia.com> Cc: linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org, dmaengine@vger.kernel.org, gnurou@gmail.com, thierry.reding@gmail.com, swarren@wwwdotorg.org, ldewangan@nvidia.com From: Dmitry Osipenko Message-ID: <5db4d7db-b1f4-c6af-de56-e8bb13ebc465@gmail.com> Date: Tue, 6 Sep 2016 15:03:43 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <319ca097-4b10-83b9-841c-52adccbb48ad@nvidia.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06.09.2016 14:33, Jon Hunter wrote: > > On 03/09/16 01:32, Nicolin Chen wrote: >> This series of patches add memcpy support for tegra210 ADMA engine. > > Thanks. Any reason you choose this DMA and not the APB DMA? The APB DMA > is more of a generic DMA and so for memcpy it would seem to be a good > choice and it is available on all Tegras not just Tegra210. > Just a small clarification: If I'm not mistaken, APB DMA is mem-to-device, while AHB DMA is mem-to-mem. So, you probably meant AHB and not the APB. > Furthermore, from a power standpoint the ADMA is in the audio power > domain and so using it for memcpy would mean the audio power domain is > turned on. It may not be a big deal for some, but given the APB is in > the CORE domain (always on when not in low-power) it seems like a better > choice for power as well. > -- Dmitry