From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752054AbaGQSbP (ORCPT ); Thu, 17 Jul 2014 14:31:15 -0400 Received: from smtp.codeaurora.org ([198.145.11.231]:33221 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751339AbaGQSbN (ORCPT ); Thu, 17 Jul 2014 14:31:13 -0400 Date: Thu, 17 Jul 2014 13:31:10 -0500 From: Andy Gross To: Vinod Koul Cc: dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org Subject: Re: [PATCH] dmaengine: qcom_bam_dma: Add descriptor flags Message-ID: <20140717183110.GB17951@qualcomm.com> References: <1401482990-26486-1-git-send-email-agross@codeaurora.org> <20140714163616.GA4387@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140714163616.GA4387@intel.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 14, 2014 at 10:06:16PM +0530, Vinod Koul wrote: > On Fri, May 30, 2014 at 03:49:50PM -0500, Andy Gross wrote: > > This patch adds support for end of transaction (EOT) and notify when done (NWD) > > hardware descriptor flags. > > > > The EOT flag requests that the peripheral assert an end of transaction interrupt > > when that descriptor is complete. It also results in special signaling protocol > > that is used between the attached peripheral and the core using the DMA > > controller. Clients will specify DMA_PREP_INTERRUPT to enable this flag. > > > > The NWD flag requests that the peripheral wait until the data has been fully > > processed by the peripheral before moving on to the next descriptor. Clients > > will specify DMA_PREP_FENCE to enable this flag. > > I am going to apply this, but pls send a follow up patch to add comments on the > flags and their behaviour. I think it is required! Will do. > > #define DESC_FLAG_EOT BIT(14) > > #define DESC_FLAG_EOB BIT(13) > > +#define DESC_FLAG_NWD BIT(12) > explaining behvaiour will help.. In the followup, I'll put in a lengthy description of the INT/EOT/NWD and how they are used in the signaling to/from the attached peripheral. Thanks! -- sent by an employee of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation