From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756632Ab1JNNje (ORCPT ); Fri, 14 Oct 2011 09:39:34 -0400 Received: from mga11.intel.com ([192.55.52.93]:24693 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756577Ab1JNNjd (ORCPT ); Fri, 14 Oct 2011 09:39:33 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.69,346,1315206000"; d="scan'208";a="78138869" Subject: Re: [PATCHv5] DMAEngine: Define interleaved transfer request api From: Vinod Koul To: Jassi Brar Cc: Barry Song <21cnbao@gmail.com>, linux-kernel@vger.kernel.org, dan.j.williams@intel.com, rmk@arm.linux.org.uk, DL-SHA-WorkGroupLinux In-Reply-To: References: <1317191992-3635-1-git-send-email-jaswinder.singh@linaro.org> <1318489410-3182-1-git-send-email-jaswinder.singh@linaro.org> Content-Type: text/plain; charset="UTF-8" Date: Fri, 14 Oct 2011 19:01:19 +0530 Message-ID: <1318599079.1546.395.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 On Fri, 2011-10-14 at 17:21 +0530, Jassi Brar wrote: > On 14 October 2011 13:02, Barry Song <21cnbao@gmail.com> wrote: > > > > what if i want a cyclic interleaved transfer? i think the cyclic > > interleaved transfer is what i want for audio dma. > > > ... we need to restore 'bool frm_irq' and add new 'bool cyclic' that > would replay the transfer(i.e, reset dma-pointers to src_start & dst_start) > after 'numf' frames have been transferred. I was thinking more on lines to have this conveyed thru a flag. Anyway I plan to work on merging device_prep_slave_sg and device_prep_cyclic to single API. Think more of device_prep_cyclic as special case with sg length one and flag to tell dmac its cyclic. Similarly here we could use/define this flag to say this transfer is also cyclic in nature and dmac then reloads the list again. That way any prep can be made cyclic in nature by just using this flag. @Barry: Why would you need to use interleaved API for audio? -- ~Vinod