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=-5.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 DC2EEC433F4 for ; Mon, 24 Sep 2018 12:44:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A04412083A for ; Mon, 24 Sep 2018 12:44:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A04412083A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org 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 S2389235AbeIXSqt (ORCPT ); Mon, 24 Sep 2018 14:46:49 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:59676 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388693AbeIXSqt (ORCPT ); Mon, 24 Sep 2018 14:46:49 -0400 Received: from localhost (ip-213-127-77-73.ip.prioritytelecom.net [213.127.77.73]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 8ED3D1099; Mon, 24 Sep 2018 12:44:49 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yoshihiro Shimoda , Vinod Koul , Sasha Levin Subject: [PATCH 4.18 223/235] dmaengine: sh: rcar-dmac: avoid to write CHCR.TE to 1 if TCR is set to 0 Date: Mon, 24 Sep 2018 13:53:29 +0200 Message-Id: <20180924113125.525792277@linuxfoundation.org> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20180924113103.999624566@linuxfoundation.org> References: <20180924113103.999624566@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review 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 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yoshihiro Shimoda [ Upstream commit 538603c6026ce769eec633bb79349f5f287519c7 ] This patch fixes an issue that unexpected retransfering happens if TCR is set to 0 before rcar_dmac_sync_tcr() writes DE bit to the CHCR register. For example, sh-sci driver can reproduce this issue like below: In rx_timer_fn(): /* CHCR DE bit may be set to 1 */ dmaengine_tx_status() rcar_dmac_tx_status() rcar_dmac_chan_get_residue() rcar_dmac_sync_tcr() /* TCR is possible to be set to 0 */ According to the description of commit 73a47bd0da66 ("dmaengine: rcar-dmac: use TCRB instead of TCR for residue"), "this buffered data will be transferred if CHCR::DE bit was cleared". So, this patch doesn't need to check TCRB register. Fixes: 73a47bd0da66 ("dmaengine: rcar-dmac: use TCRB instead of TCR for residue") Signed-off-by: Yoshihiro Shimoda Signed-off-by: Vinod Koul Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/dma/sh/rcar-dmac.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/dma/sh/rcar-dmac.c +++ b/drivers/dma/sh/rcar-dmac.c @@ -774,8 +774,9 @@ static void rcar_dmac_sync_tcr(struct rc /* make sure all remaining data was flushed */ rcar_dmac_chcr_de_barrier(chan); - /* back DE */ - rcar_dmac_chan_write(chan, RCAR_DMACHCR, chcr); + /* back DE if remain data exists */ + if (rcar_dmac_chan_read(chan, RCAR_DMATCR)) + rcar_dmac_chan_write(chan, RCAR_DMACHCR, chcr); } static void rcar_dmac_chan_halt(struct rcar_dmac_chan *chan)