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=-8.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 D1DD1CA9EB9 for ; Wed, 23 Oct 2019 18:55:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A850321928 for ; Wed, 23 Oct 2019 18:55:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=cogentembedded-com.20150623.gappssmtp.com header.i=@cogentembedded-com.20150623.gappssmtp.com header.b="UYzrIeVT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404284AbfJWSzq (ORCPT ); Wed, 23 Oct 2019 14:55:46 -0400 Received: from mail-lf1-f66.google.com ([209.85.167.66]:40418 "EHLO mail-lf1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390528AbfJWSzq (ORCPT ); Wed, 23 Oct 2019 14:55:46 -0400 Received: by mail-lf1-f66.google.com with SMTP id i15so9529930lfo.7 for ; Wed, 23 Oct 2019 11:55:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cogentembedded-com.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:organization:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=siFQiuzIjrmxUWWr+3F2Xxv7kAaf2tX6TRSs0T4RCwc=; b=UYzrIeVTtIf1BJjJfLLhqwsRZMgn5vMmjhQA8UDNkOK272ppmCgLZXF4Am3TyqIp3l XnhO2K7EO4RQYklnDB0VLmFyRoo+eaXLsdPVsk5mFGzuGFmE0b+upNFdyanOPlQqYNOw snGY85gcdtWLrbbJ3o+bizmGfgw3ucS0brj5IAW6coBAOBq6+lq1FAKcpOVY1924eKGM tvRJ0S1jQAQSg2PQdBxlTwhuSHYrAjkG9GmOkTxYPxZaU7DwfiaFQdc5UQjmOgBYKZPA t6xQ37w4qA6SnJFVzo6CbgNZFGShTMHiGE8622aE2Wr4lGqwJcN+JXb3pHGhYR5sJomA uRTw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:organization :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=siFQiuzIjrmxUWWr+3F2Xxv7kAaf2tX6TRSs0T4RCwc=; b=Un1Z9n7G0ANf0s3L0OUUB+EELR1vurbvBbfOER8MX4cZHcqY4XXVpsq7GgPg2qvmFN LG5c6SZ8uKsjNfh+ODurGSyRQtvhOuUPOlXRGzjLW3DcOSt8RVPq5rIqBI3UlHjJCi9v zkklFOHiQg/YFWXjbJw9X61ZsQ+UEoqk/ityHS7Ugb2+twXkTMCEfIUYr2mkNNL7xcCJ 5rocoplh9wWA/ZtGPrNzNjzVwQ/z7dV7j/eAgjLhWdXdfP0T3c3QtsoF0IhJDha1W30P aI4eaGA62mbDc1FQfuk2e6nUY70KlAjZilWF+t4A4mOjshl4CmRVtQTCkndL03i+NqvO dJDA== X-Gm-Message-State: APjAAAVkB5bh2flLa6hteVffA783LeDhlrz9aG7GLY1vFEC5A/Gpwgvb V4+E+opzf2EeTkKZrxw1czOI3g== X-Google-Smtp-Source: APXvYqxDjviSod7jwUJYUuawdEHDdl/NXPVH+ubWyrRrncUtwvl48hJyYqE9JcUCV9380lASFQ0wWQ== X-Received: by 2002:a19:6a08:: with SMTP id u8mr25275437lfu.74.1571856942801; Wed, 23 Oct 2019 11:55:42 -0700 (PDT) Received: from wasted.cogentembedded.com ([2a00:1fa0:4201:cc87:e4a0:50f7:ca47:8e61]) by smtp.gmail.com with ESMTPSA id b141sm10973957lfg.67.2019.10.23.11.55.41 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 23 Oct 2019 11:55:42 -0700 (PDT) Subject: Re: [PATCH] dmaengine: cppi41: Fix cppi41_dma_prep_slave_sg() when idle To: Tony Lindgren , Dan Williams , Vinod Koul Cc: Alexandre Bailon , Andy Shevchenko , Bin Liu , Daniel Mack , Felipe Balbi , George Cherian , Grygorii Strashko , Johan Hovold , Peter Ujfalusi , Sekhar Nori , Sebastian Andrzej Siewior , dmaengine@vger.kernel.org, linux-usb@vger.kernel.org, linux-omap@vger.kernel.org, giulio.benetti@benettiengineering.com, Sebastian Reichel , Skvortsov , Yegor Yefremov References: <20191023153138.23442-1-tony@atomide.com> From: Sergei Shtylyov Organization: Cogent Embedded Message-ID: <6996a5de-215b-f9a2-1aeb-5eeed1b7cf8d@cogentembedded.com> Date: Wed, 23 Oct 2019 21:55:40 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <20191023153138.23442-1-tony@atomide.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-MW Content-Transfer-Encoding: 7bit Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org Hello! On 10/23/2019 06:31 PM, Tony Lindgren wrote: > Yegor Yefremov reported that musb and ftdi > uart can fail for the first open of the uart unless connected using > a hub. > > This is because the first dma call done by musb_ep_program() must wait > if cppi41 is PM runtime suspended. Otherwise musb_ep_program() continues > with other non-dma packets before the DMA transfer is started causing at > least ftdi uarts to fail to receive data. > > Let's fix the issue by waking up cppi41 with PM runtime calls added to > cppi41_dma_prep_slave_sg() and return NULL if still idled. This way we > have musb_ep_program() continue with PIO until cppi41 is awake. > > Fixes: fdea2d09b997 ("dmaengine: cppi41: Add basic PM runtime support") > Cc: Bin Liu > Cc: giulio.benetti@benettiengineering.com > Cc: Sebastian Andrzej Siewior > Cc: Sebastian Reichel > Cc: Skvortsov > Reported-by: Yegor Yefremov > Signed-off-by: Tony Lindgren > --- > > Please consider adding Cc stable v4.9+ tag when committing > > --- > drivers/dma/ti/cppi41.c | 21 ++++++++++++++++++++- > 1 file changed, 20 insertions(+), 1 deletion(-) > > diff --git a/drivers/dma/ti/cppi41.c b/drivers/dma/ti/cppi41.c > --- a/drivers/dma/ti/cppi41.c > +++ b/drivers/dma/ti/cppi41.c > @@ -586,9 +586,22 @@ static struct dma_async_tx_descriptor *cppi41_dma_prep_slave_sg( > enum dma_transfer_direction dir, unsigned long tx_flags, void *context) > { > struct cppi41_channel *c = to_cpp41_chan(chan); > + struct dma_async_tx_descriptor *txd = NULL; > + struct cppi41_dd *cdd = c->cdd; > struct cppi41_desc *d; > struct scatterlist *sg; > unsigned int i; > + int error; > + > + error = pm_runtime_get(cdd->ddev.dev); > + if (error < 0) { I'd call that variable 'status', comparison (error < 0) just doesn't look right. If it was *if* (error), it would have been more correct. > + pm_runtime_put_noidle(cdd->ddev.dev); > + > + return NULL; > + } > + > + if (cdd->is_suspended) > + goto err_out_not_ready; > > d = c->desc; > for_each_sg(sgl, sg, sg_len, i) { [...] MBR, Sergei