From patchwork Thu Sep 26 15:06:36 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Markus Pargmann X-Patchwork-Id: 2949171 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 3DCEE9F288 for ; Thu, 26 Sep 2013 15:08:45 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id A76D22031A for ; Thu, 26 Sep 2013 15:08:40 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5680220306 for ; Thu, 26 Sep 2013 15:08:39 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VPDAW-00031t-OK; Thu, 26 Sep 2013 15:07:52 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1VPDAH-0001Ge-A3; Thu, 26 Sep 2013 15:07:37 +0000 Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VPD9y-0001Dq-Hx for linux-arm-kernel@lists.infradead.org; Thu, 26 Sep 2013 15:07:19 +0000 Received: from dude.hi.pengutronix.de ([2001:6f8:1178:2:21e:67ff:fe11:9c5c]) by metis.ext.pengutronix.de with esmtp (Exim 4.72) (envelope-from ) id 1VPD9P-0005qH-EY; Thu, 26 Sep 2013 17:06:43 +0200 Received: from mpa by dude.hi.pengutronix.de with local (Exim 4.80) (envelope-from ) id 1VPD9O-0007w6-Ef; Thu, 26 Sep 2013 17:06:42 +0200 From: Markus Pargmann To: Vinod Koul Subject: [PATCH 3/3] dma: mxs-dma: Pause channel while prep_dma_cyclic Date: Thu, 26 Sep 2013 17:06:36 +0200 Message-Id: <1380207996-27257-4-git-send-email-mpa@pengutronix.de> X-Mailer: git-send-email 1.8.4.rc3 In-Reply-To: <1380207996-27257-1-git-send-email-mpa@pengutronix.de> References: <1380207996-27257-1-git-send-email-mpa@pengutronix.de> X-SA-Exim-Connect-IP: 2001:6f8:1178:2:21e:67ff:fe11:9c5c X-SA-Exim-Mail-From: mpa@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-arm-kernel@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130926_110718_835642_51DF0680 X-CRM114-Status: GOOD ( 12.84 ) X-Spam-Score: -4.3 (----) Cc: Markus Pargmann , kernel@pengutronix.de, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-6.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Using mxs-dma with pcm-dmaengine with small period-length can in some cases lead to strange audio effects. This patch pauses the DMA channel while preparing cyclic DMA commands. I tested with mx28 and period-length of 160. Signed-off-by: Markus Pargmann --- drivers/dma/mxs-dma.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/dma/mxs-dma.c b/drivers/dma/mxs-dma.c index 13c7d83..bdde315 100644 --- a/drivers/dma/mxs-dma.c +++ b/drivers/dma/mxs-dma.c @@ -568,8 +568,8 @@ static struct dma_async_tx_descriptor *mxs_dma_prep_dma_cyclic( if (mxs_chan->status == DMA_IN_PROGRESS) return NULL; - mxs_chan->status = DMA_IN_PROGRESS; - mxs_chan->flags |= MXS_DMA_SG_LOOP; + mxs_dma_pause_chan(mxs_chan); + mxs_dma_reset_chan(mxs_chan); if (num_periods > NUM_CCW) { dev_err(mxs_dma->dma_device.dev, @@ -609,6 +609,11 @@ static struct dma_async_tx_descriptor *mxs_dma_prep_dma_cyclic( i++; } + mxs_dma_resume_chan(mxs_chan); + + mxs_chan->status = DMA_IN_PROGRESS; + mxs_chan->flags |= MXS_DMA_SG_LOOP; + mxs_chan->desc_count = i; return &mxs_chan->desc;