From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755353AbdABIiF (ORCPT ); Mon, 2 Jan 2017 03:38:05 -0500 Received: from mga03.intel.com ([134.134.136.65]:14857 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750944AbdABIiE (ORCPT ); Mon, 2 Jan 2017 03:38:04 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,432,1477983600"; d="scan'208";a="1088896455" Message-ID: <1483346280.9552.181.camel@linux.intel.com> Subject: Re: dmaengine: dw-dmac: Custom cyclic API (Why?) From: Andy Shevchenko To: Jose Abreu , "dmaengine@vger.kernel.org" , "linux-kernel@vger.kernel.org" , vireshk@kernel.org Date: Mon, 02 Jan 2017 10:38:00 +0200 In-Reply-To: <99eeb12c-fd4f-7982-4832-61116fd641d3@synopsys.com> References: <99eeb12c-fd4f-7982-4832-61116fd641d3@synopsys.com> Organization: Intel Finland Oy Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.3-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2016-12-30 at 12:05 +0000, Jose Abreu wrote: > ++dw-dmac Maintainers > > > On 30-12-2016 11:32, Jose Abreu wrote: > > Hi All, > > > > > > I am going to work with dw-dmac AHB controller and I wanted to > > use SND_DMAENGINE_PCM. In order to use this, a standard DMA > > driver with cyclic support is needed. I found out that dw-dmac is > > capable of cyclic transfers but instead of using the DMA engine > > standard cyclic API it uses a custom API. Is there any specific > > reason for this? What is the effort to change the custom API to a > > standard DMA engine cyclic API? > > Because it was a predecessor of generic implementation. I used to have some semi-finished patch to switch to generic API, though at that point I had no means to test it. Since I eventually got iDMA 32-bit, which is used as LPE Audio DMA engine, support in my branch I might test it in the future, though I think someone else would be much faster than me. So, I can share whatever I have to the topic with someone who is really interested to do that task. -- Andy Shevchenko Intel Finland Oy