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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5CE15CDB465 for ; Mon, 16 Oct 2023 11:11:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231975AbjJPLLH (ORCPT ); Mon, 16 Oct 2023 07:11:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35178 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231442AbjJPLLG (ORCPT ); Mon, 16 Oct 2023 07:11:06 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E0FF483; Mon, 16 Oct 2023 04:11:03 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 128F2C433C8; Mon, 16 Oct 2023 11:11:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697454663; bh=lVB3Zy9EHqhxD+7XTnrniBL/mRSy6WczNg24vNkvBcc=; h=Date:From:To:Subject:References:In-Reply-To:From; b=NgcyglY9QC5upCi7f7lr2wW18jKwF0fCzlqrPjMUJXth7LhMKOWBUU9klax5RYlZu Yt5uPzLb3XZjPlSCsLcF+ZfQn1Ve4oEMf6DDAqcO9U4L7wxvnEGZArpA7qy6TPn2mv M4I5XAQXmz/8+NuMYzxjQZdBFEjn6tp+L85sJ42ucrDGLgP+Ii/wA5HNUbuy47WKhv R9wIqRRGDK917H0Ai7C9WpNiv1L4Vr7TohZ9DEEwPWVLQKDpbh5tqznz+mq4DMwlGh 9DNONA/aDFkS2K5L7BsbOjNpWqHJfXMj+WyIC4lXEC8qCDNlRjAzdO4PxCOfYR0L9z CDQPX97RLrGXg== Date: Mon, 16 Oct 2023 16:41:00 +0530 From: Vinod Koul To: Amelie Delaunay , Maxime Coquelin , Alexandre Torgue , M'boumba Cedric Madianga , Pierre-Yves MORDRET , stable@vger.kernel.org, dmaengine@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] dmaengine: stm32-mdma: correct desc prep when channel running Message-ID: References: <20231009082450.452877-1-amelie.delaunay@foss.st.com> <20231009090213.GA1547647@gnbcxd0016.gnb.st.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20231009090213.GA1547647@gnbcxd0016.gnb.st.com> Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 09-10-23, 11:02, Alain Volmat wrote: > Hi Amélie, > > thanks a lot. > > Tested-by: Alain Volmat Please **do ** not ** top post! > > Regards, > Alain > > On Mon, Oct 09, 2023 at 10:24:50AM +0200, Amelie Delaunay wrote: > > From: Alain Volmat > > > > In case of the prep descriptor while the channel is already running, the > > CCR register value stored into the channel could already have its EN bit > > set. This would lead to a bad transfer since, at start transfer time, > > enabling the channel while other registers aren't yet properly set. > > To avoid this, ensure to mask the CCR_EN bit when storing the ccr value > > into the mdma channel structure. > > > > Fixes: a4ffb13c8946 ("dmaengine: Add STM32 MDMA driver") > > Signed-off-by: Alain Volmat > > Signed-off-by: Amelie Delaunay > > Cc: stable@vger.kernel.org > > --- > > drivers/dma/stm32-mdma.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c > > index bae08b3f55c7..f414efdbd809 100644 > > --- a/drivers/dma/stm32-mdma.c > > +++ b/drivers/dma/stm32-mdma.c > > @@ -489,7 +489,7 @@ static int stm32_mdma_set_xfer_param(struct stm32_mdma_chan *chan, > > src_maxburst = chan->dma_config.src_maxburst; > > dst_maxburst = chan->dma_config.dst_maxburst; > > > > - ccr = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id)); > > + ccr = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id)) & ~STM32_MDMA_CCR_EN; > > ctcr = stm32_mdma_read(dmadev, STM32_MDMA_CTCR(chan->id)); > > ctbr = stm32_mdma_read(dmadev, STM32_MDMA_CTBR(chan->id)); > > > > @@ -965,7 +965,7 @@ stm32_mdma_prep_dma_memcpy(struct dma_chan *c, dma_addr_t dest, dma_addr_t src, > > if (!desc) > > return NULL; > > > > - ccr = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id)); > > + ccr = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id)) & ~STM32_MDMA_CCR_EN; > > ctcr = stm32_mdma_read(dmadev, STM32_MDMA_CTCR(chan->id)); > > ctbr = stm32_mdma_read(dmadev, STM32_MDMA_CTBR(chan->id)); > > cbndtr = stm32_mdma_read(dmadev, STM32_MDMA_CBNDTR(chan->id)); > > -- > > 2.25.1 > > -- ~Vinod