From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751968AbdC0FUY (ORCPT ); Mon, 27 Mar 2017 01:20:24 -0400 Received: from mga06.intel.com ([134.134.136.31]:45681 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751911AbdC0FUW (ORCPT ); Mon, 27 Mar 2017 01:20:22 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.36,229,1486454400"; d="scan'208";a="1147285752" Date: Mon, 27 Mar 2017 10:51:38 +0530 From: Vinod Koul To: jiada_wang@mentor.com Cc: dan.j.williams@intel.com, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] dma: imx-sdma: add 1ms delay to ensure SDMA channel is stopped Message-ID: <20170327052138.GG9308@localhost> References: <1489731129-3166-1-git-send-email-jiada_wang@mentor.com> <1489731129-3166-2-git-send-email-jiada_wang@mentor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1489731129-3166-2-git-send-email-jiada_wang@mentor.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 16, 2017 at 11:12:09PM -0700, jiada_wang@mentor.com wrote: > From: Jiada Wang > > sdma_disable_channel() cannot ensure dma is stopped to access > module's FIFOs. There is chance SDMA core is running and accessing > BD when disable of corresponding channel, this may cause sometimes > even after call of .sdma_disable_channel(), SDMA core still be > running and accessing module's FIFOs. > > According to NXP R&D team a delay of one BD SDMA cost time (maximum > is 1ms) should be added after disable of the channel bit, to ensure > SDMA core has really been stopped after SDMA clients call > .device_terminate_all. > > This patch introduces adds a new function sdma_disable_channel_with_delay() > which simply adds 1ms delay after call sdma_disable_channel(), > and set it as .device_terminate_all. Applied after fixing the subsystem name. -- ~Vinod