From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B036FECDFD0 for ; Fri, 14 Sep 2018 14:29:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5C84120861 for ; Fri, 14 Sep 2018 14:29:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5C84120861 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728080AbeINToP convert rfc822-to-8bit (ORCPT ); Fri, 14 Sep 2018 15:44:15 -0400 Received: from mail.bootlin.com ([62.4.15.54]:44393 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726902AbeINToP (ORCPT ); Fri, 14 Sep 2018 15:44:15 -0400 Received: by mail.bootlin.com (Postfix, from userid 110) id F3535206FF; Fri, 14 Sep 2018 16:29:27 +0200 (CEST) Received: from xps13 (unknown [37.170.158.44]) by mail.bootlin.com (Postfix) with ESMTPSA id 235C520379; Fri, 14 Sep 2018 16:29:27 +0200 (CEST) Date: Fri, 14 Sep 2018 16:29:23 +0200 From: Miquel Raynal To: Masahiro Yamada Cc: linux-mtd@lists.infradead.org, Boris Brezillon , Steffen Trumtrar , linux-kernel@vger.kernel.org, Marek Vasut , Brian Norris , Richard Weinberger , David Woodhouse Subject: Re: [PATCH] mtd: rawnand: denali: fix a race condition when DMA is kicked Message-ID: <20180914162923.05c44fcc@xps13> In-Reply-To: <1536818329-11068-1-git-send-email-yamada.masahiro@socionext.com> References: <1536818329-11068-1-git-send-email-yamada.masahiro@socionext.com> Organization: Bootlin X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Masahiro Yamada wrote on Thu, 13 Sep 2018 14:58:49 +0900: > I thought the read-back of the DMA_ENABLE register was unnecessary > (at least it is working on my boards), then deleted it in commit > 586a2c52909d ("mtd: nand: denali: squash denali_enable_dma() helper > into caller"). Sorry, I was wrong - it caused a timing issue on > Cyclone5 SoCFPGAs. > > Revive the register read-back, commenting why this is necessary. > > Fixes: 586a2c52909d ("mtd: nand: denali: squash denali_enable_dma() helper into caller") > Reported-by: Steffen Trumtrar > Signed-off-by: Masahiro Yamada Reviewed-by: Miquel Raynal Thanks, Miquèl