From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758339AbcAKGK4 (ORCPT ); Mon, 11 Jan 2016 01:10:56 -0500 Received: from mail-pf0-f170.google.com ([209.85.192.170]:36151 "EHLO mail-pf0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758298AbcAKGKz (ORCPT ); Mon, 11 Jan 2016 01:10:55 -0500 Date: Mon, 11 Jan 2016 11:40:51 +0530 From: Viresh Kumar To: Mans Rullgard Cc: Viresh Kumar , Andy Shevchenko , Dan Williams , Vinod Koul , dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] dmaengine: dw: fix cyclic transfers Message-ID: <20160111061051.GC3448@ubuntu> References: <1452459243-23739-1-git-send-email-mans@mansr.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1452459243-23739-1-git-send-email-mans@mansr.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 10-01-16, 20:54, Mans Rullgard wrote: > Commit 61e183f83069 ("dmaengine/dw_dmac: Reconfigure interrupt and > chan_cfg register on resume") moved some channel initialisation to > a new function which must be called before starting a transfer. > > This adds the necessary dwc_initialize() call to dw_dma_cyclic_start() > which was missed in the original commit. > > Fixes: 61e183f83069 ("dmaengine/dw_dmac: Reconfigure interrupt and chan_cfg register on resume") > Signed-off-by: Mans Rullgard > --- > Andy, do you want to collect this with your other patches? It's trivial > enough that it can go in separately without conflicts too. > --- > drivers/dma/dw/core.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c > index 7067b6ddc1db..2917f75b67b4 100644 > --- a/drivers/dma/dw/core.c > +++ b/drivers/dma/dw/core.c > @@ -1265,6 +1265,8 @@ int dw_dma_cyclic_start(struct dma_chan *chan) > return -EBUSY; > } > > + dwc_initialize(dwc); > + > dma_writel(dw, CLEAR.ERROR, dwc->mask); > dma_writel(dw, CLEAR.XFER, dwc->mask); Ahh, that's a very very old bug :( Okay, things got cleaned up by putting the dwc_initialize() call within dwc_dostart() and so it worked for all other DMA APIs. What about calling dwc_dostart() from within dw_dma_cyclic_start()? That will simplify it and remove code duplication issue as well. -- viresh