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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 4175DC10F25 for ; Sat, 7 Mar 2020 15:08:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1B368206D5 for ; Sat, 7 Mar 2020 15:08:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583593689; bh=RQpDqkyyxmFg9c3rc/jOhh1yQA+Hq7TSDoK7PRzgQ0I=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=a+Gjl9M7U5Gk1N8WBBle8jRmkePKlZzfkQdgjwCulg/867OsSvUkl86ndyNOk8g/Q e9Cgqk6ysa0Fkp5k5SBvEEMXEraY7bt1E8PjBOLGzrLZAHgiZO83KgNJYAJv+/zdLb 7D8APjUl9lGOl0zGQ1eW1HCqa+c7BL4KeidmCPl0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726252AbgCGPII (ORCPT ); Sat, 7 Mar 2020 10:08:08 -0500 Received: from mail.kernel.org ([198.145.29.99]:47734 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726065AbgCGPIH (ORCPT ); Sat, 7 Mar 2020 10:08:07 -0500 Received: from archlinux (cpc149474-cmbg20-2-0-cust94.5-4.cable.virginm.net [82.4.196.95]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 91AEB20675; Sat, 7 Mar 2020 15:08:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583593686; bh=RQpDqkyyxmFg9c3rc/jOhh1yQA+Hq7TSDoK7PRzgQ0I=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=QRgraDd5g2lyhqe/VHYJfWH8Kx0++0nF5g8fRF/GUXbIuEPV9DQEEa1eot9plToWK vpMZCqgUDGZG+77uAOPhuyjJUC1uClW+UBh0S8S+YKoo8YF15uRlT08pYMHJjPDCJJ PsQvSvEBfJGiP17xk+Yba/GFY1PuY6mHGdbrQqAI= Date: Sat, 7 Mar 2020 15:08:01 +0000 From: Jonathan Cameron To: Olivier Moysan Cc: , , , , , , , , , Subject: Re: [PATCH] iio: adc: stm32-adc: fix sleep in atomic context Message-ID: <20200307150801.011f35b2@archlinux> In-Reply-To: <20200306155335.6019-1-olivier.moysan@st.com> References: <20200306155335.6019-1-olivier.moysan@st.com> X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 6 Mar 2020 16:53:35 +0100 Olivier Moysan wrote: > This commit fixes the following error: > "BUG: sleeping function called from invalid context at kernel/irq/chip.c" > > In DMA mode suppress the trigger irq handler, and make the buffer > transfers directly in DMA callback, instead. > > Signed-off-by: Olivier Moysan looks good to me, but... fixes tag? We probably want to backport this so good to know when we introduced the issue. Thanks, Jonathan > --- > This solution has been already discussed in the thread > https://lkml.org/lkml/2019/3/30/171, and applied in STM32 DFSDM driver: > e19ac9d9a978 ("iio: adc: stm32-dfsdm: fix sleep in atomic context") > --- > drivers/iio/adc/stm32-adc.c | 31 ++++++++++++++++++++++++++++--- > 1 file changed, 28 insertions(+), 3 deletions(-) > > diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c > index 80c3f963527b..ae622ee6d08c 100644 > --- a/drivers/iio/adc/stm32-adc.c > +++ b/drivers/iio/adc/stm32-adc.c > @@ -1418,8 +1418,30 @@ static unsigned int stm32_adc_dma_residue(struct stm32_adc *adc) > static void stm32_adc_dma_buffer_done(void *data) > { > struct iio_dev *indio_dev = data; > + struct stm32_adc *adc = iio_priv(indio_dev); > + int residue = stm32_adc_dma_residue(adc); > + > + /* > + * In DMA mode the trigger services of IIO are not used > + * (e.g. no call to iio_trigger_poll). > + * Calling irq handler associated to the hardware trigger is not > + * relevant as the conversions have already been done. Data > + * transfers are performed directly in DMA callback instead. > + * This implementation avoids to call trigger irq handler that > + * may sleep, in an atomic context (DMA irq handler context). > + */ > + dev_dbg(&indio_dev->dev, "%s bufi=%d\n", __func__, adc->bufi); > > - iio_trigger_poll_chained(indio_dev->trig); > + while (residue >= indio_dev->scan_bytes) { > + u16 *buffer = (u16 *)&adc->rx_buf[adc->bufi]; > + > + iio_push_to_buffers(indio_dev, buffer); > + > + residue -= indio_dev->scan_bytes; > + adc->bufi += indio_dev->scan_bytes; > + if (adc->bufi >= adc->rx_buf_sz) > + adc->bufi = 0; > + } > } > > static int stm32_adc_dma_start(struct iio_dev *indio_dev) > @@ -1845,6 +1867,7 @@ static int stm32_adc_probe(struct platform_device *pdev) > { > struct iio_dev *indio_dev; > struct device *dev = &pdev->dev; > + irqreturn_t (*handler)(int irq, void *p) = NULL; > struct stm32_adc *adc; > int ret; > > @@ -1911,9 +1934,11 @@ static int stm32_adc_probe(struct platform_device *pdev) > if (ret < 0) > return ret; > > + if (!adc->dma_chan) > + handler = &stm32_adc_trigger_handler; > + > ret = iio_triggered_buffer_setup(indio_dev, > - &iio_pollfunc_store_time, > - &stm32_adc_trigger_handler, > + &iio_pollfunc_store_time, handler, > &stm32_adc_buffer_setup_ops); > if (ret) { > dev_err(&pdev->dev, "buffer setup failed\n");