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Wed, 27 Mar 2019 12:51:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1553691124; bh=urVAPS/GNo9euf8XE9fFGRfQZaP4E5uDf+TroIrgCYc=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=YWy7obH8F1SXikARiT38tHhCm5MRYiGI3jyz273NXML/wnlNSNWKXKmRacNxm78oU bzSlTPp91QyGaMHn2QYn0LTv4UKBE6SED4dkGXRtq7O1gb3F+dACEMK2tFRqx0eLVT oY6UW0bYJPDVA4xf7l4XkTAwnCdmLODzNZVYx6vE= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 046CC608FC Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=mojha@codeaurora.org Subject: Re: [PATCH] iio: adc: stm32: fix sleep inside atomic section when using DMA To: Fabrice Gasnier , jic23@kernel.org References: <1553604244-10922-1-git-send-email-fabrice.gasnier@st.com> From: Mukesh Ojha Message-ID: <647777da-8077-6390-9778-08bef3d13074@codeaurora.org> Date: Wed, 27 Mar 2019 18:21:56 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.6.0 MIME-Version: 1.0 In-Reply-To: <1553604244-10922-1-git-send-email-fabrice.gasnier@st.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190327_055206_430026_92832DD7 X-CRM114-Status: GOOD ( 22.35 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: lars@metafoo.de, alexandre.torgue@st.com, linux-iio@vger.kernel.org, pmeerw@pmeerw.net, linux-kernel@vger.kernel.org, mcoquelin.stm32@gmail.com, knaack.h@gmx.de, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 3/26/2019 6:14 PM, Fabrice Gasnier wrote: > Enabling CONFIG_DEBUG_ATOMIC_SLEEP=y triggers this BUG message: > BUG: sleeping function called from invalid context at kernel/irq/chip.c... > > Call stack is as follows: > - __might_sleep > - handle_nested_irq <-- Expects threaded irq > - iio_trigger_poll_chained > - stm32_adc_dma_buffer_done > - vchan_complete > - tasklet_action_common > - tasklet_action > - __do_softirq <-- DMA completion raises a tasklet > - irq_exit > - __handle_domain_irq <-- DMA IRQ > - gic_handle_irq > > IIO expects threaded interrupt context when calling: > - iio_trigger_poll_chained() > Or it expects interrupt context when calling: > - iio_trigger_poll() > > This patch triggers an IRQ upon stm32_adc_dma_buffer_done() DMA callback > call, so the IIO trigger poll API gets called from IRQ context. > > Fixes: 2763ea0585c9 ("iio: adc: stm32: add optional dma support") > > Signed-off-by: Fabrice Gasnier Reviewed-by: Mukesh Ojha -Mukesh > --- > drivers/iio/adc/Kconfig | 1 + > drivers/iio/adc/stm32-adc.c | 32 ++++++++++++++++++++++++++++++-- > 2 files changed, 31 insertions(+), 2 deletions(-) > > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig > index 76db6e5..059407a 100644 > --- a/drivers/iio/adc/Kconfig > +++ b/drivers/iio/adc/Kconfig > @@ -775,6 +775,7 @@ config STM32_ADC_CORE > select MFD_STM32_TIMERS > select IIO_STM32_TIMER_TRIGGER > select IIO_TRIGGERED_BUFFER > + select IRQ_WORK > help > Select this option to enable the core driver for STMicroelectronics > STM32 analog-to-digital converter (ADC). > diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c > index 205e169..1aa3189 100644 > --- a/drivers/iio/adc/stm32-adc.c > +++ b/drivers/iio/adc/stm32-adc.c > @@ -20,6 +20,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -297,6 +298,7 @@ struct stm32_adc_cfg { > * @smpr_val: sampling time settings (e.g. smpr1 / smpr2) > * @cal: optional calibration data on some devices > * @chan_name: channel name array > + * @work: irq work used to call trigger poll routine > */ > struct stm32_adc { > struct stm32_adc_common *common; > @@ -320,6 +322,7 @@ struct stm32_adc { > u32 smpr_val[2]; > struct stm32_adc_calib cal; > char chan_name[STM32_ADC_CH_MAX][STM32_ADC_CH_SZ]; > + struct irq_work work; > }; > > struct stm32_adc_diff_channel { > @@ -1473,11 +1476,32 @@ static unsigned int stm32_adc_dma_residue(struct stm32_adc *adc) > return 0; > } > > +static void stm32_adc_dma_irq_work(struct irq_work *work) > +{ > + struct stm32_adc *adc = container_of(work, struct stm32_adc, work); > + struct iio_dev *indio_dev = iio_priv_to_dev(adc); > + > + /* > + * iio_trigger_poll calls generic_handle_irq(). So, it requires hard > + * irq context, and cannot be called directly from dma callback, > + * dma cb has to schedule this work instead. > + */ > + iio_trigger_poll(indio_dev->trig); > +} > + > static void stm32_adc_dma_buffer_done(void *data) > { > struct iio_dev *indio_dev = data; > + struct stm32_adc *adc = iio_priv(indio_dev); > > - iio_trigger_poll_chained(indio_dev->trig); > + /* > + * Invoques iio_trigger_poll() from hard irq context: We can't > + * call iio_trigger_poll() nor iio_trigger_poll_chained() > + * directly from DMA callback (under tasklet e.g. softirq). > + * They require respectively HW IRQ and threaded IRQ context > + * as it might sleep. > + */ > + irq_work_queue(&adc->work); > } > > static int stm32_adc_dma_start(struct iio_dev *indio_dev) > @@ -1585,8 +1609,10 @@ static void __stm32_adc_buffer_predisable(struct iio_dev *indio_dev) > if (!adc->dma_chan) > stm32_adc_conv_irq_disable(adc); > > - if (adc->dma_chan) > + if (adc->dma_chan) { > dmaengine_terminate_all(adc->dma_chan); > + irq_work_sync(&adc->work); > + } > > if (stm32_adc_set_trig(indio_dev, NULL)) > dev_err(&indio_dev->dev, "Can't clear trigger\n"); > @@ -1872,6 +1898,8 @@ static int stm32_adc_dma_request(struct iio_dev *indio_dev) > if (ret) > goto err_free; > > + init_irq_work(&adc->work, stm32_adc_dma_irq_work); > + > return 0; > > err_free: _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel