From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: Re: [PATCH v2 2/3] dmaengine: Add driver for NVIDIA Tegra AHB DMA controller Date: Fri, 6 Oct 2017 21:02:59 +0300 Message-ID: References: <9ef93a0054a6a2e27b72e5bfeebe81e5ab11a224.1507073384.git.digetx@gmail.com> <58f8c049-4408-d6a7-7452-f5be8041b7b5@nvidia.com> <72374a74-f6bd-256f-73c0-fa970a2e1576@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jon Hunter , Thierry Reding , Vinod Koul , Laxman Dewangan , Stephen Warren Cc: dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-tegra@vger.kernel.org On 06.10.2017 18:50, Jon Hunter wrote: > > On 06/10/17 16:26, Dmitry Osipenko wrote: >> On 06.10.2017 16:11, Jon Hunter wrote: >>> >>> On 04/10/17 00:58, Dmitry Osipenko wrote: >>>> AHB DMA controller presents on Tegra20/30 SoC's, it supports transfers >>>> memory <-> AHB bus peripherals as well as mem-to-mem transfers. Driver >>>> doesn't yet implement transfers larger than 64K and scatter-gather >>>> transfers that have NENT > 1, HW doesn't have native support for these >>>> cases, mem-to-mem isn't implemented as well. >>> >>> The APB DMA does not have h/w support for sg-transfers either, but >>> transfer request are placed on a list. Can we not do the same for AHB? >>> >> >> We can, but I'm not going to implement it without a use-case. It could be done >> later if needed. > > OK, that's fine, maybe state that above. > It just occurred to me that you are meaning to state that there is no use-case, I'll mention it in the commit message.