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Fri, 06 Mar 2020 16:54:53 +0100 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 7F20810003A; Fri, 6 Mar 2020 16:54:45 +0100 (CET) Received: from Webmail-eu.st.com (sfhdag6node2.st.com [10.75.127.17]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 4C9522BE23F; Fri, 6 Mar 2020 16:54:45 +0100 (CET) Received: from localhost (10.75.127.45) by SFHDAG6NODE2.st.com (10.75.127.17) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Fri, 6 Mar 2020 16:54:44 +0100 From: Olivier Moysan To: , , , , , , , Subject: [PATCH] iio: adc: stm32-adc: fix sleep in atomic context Date: Fri, 6 Mar 2020 16:53:35 +0100 Message-ID: <20200306155335.6019-1-olivier.moysan@st.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.75.127.45] X-ClientProxiedBy: SFHDAG1NODE3.st.com (10.75.127.3) To SFHDAG6NODE2.st.com (10.75.127.17) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138, 18.0.572 definitions=2020-03-06_05:2020-03-06, 2020-03-06 signatures=0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200306_075504_274422_49D1FEB2 X-CRM114-Status: GOOD ( 15.26 ) X-Spam-Score: -0.9 (/) X-Spam-Report: SpamAssassin version 3.4.3 on bombadil.infradead.org summary: Content analysis details: (-0.9 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at https://www.dnswl.org/, low trust [62.209.51.94 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-iio@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org 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 --- 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");