blob: 542b46d2917f22952d9268f458b10661f5efab0a [file] [log] [blame]
From 05731fdb8b9fb8a0de5c788ed40c9d15decdf898 Mon Sep 17 00:00:00 2001
From: Olivier Moysan <olivier.moysan@st.com>
Date: Tue, 21 Jan 2020 12:02:56 +0100
Subject: [PATCH] iio: adc: stm32-dfsdm: fix sleep in atomic context
commit e19ac9d9a978f8238a85a28ed624094a497d5ae6 upstream.
This commit fixes the error message:
"BUG: sleeping function called from invalid context at kernel/irq/chip.c"
Suppress the trigger irq handler. Make the buffer transfers directly
in DMA callback, instead.
Push buffers without timestamps, as timestamps are not supported
in DFSDM driver.
Fixes: 11646e81d775 ("iio: adc: stm32-dfsdm: add support for buffer modes")
Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
index 6b90a40882f2..9016f40f4d60 100644
--- a/drivers/iio/adc/stm32-dfsdm-adc.c
+++ b/drivers/iio/adc/stm32-dfsdm-adc.c
@@ -779,29 +779,6 @@ static unsigned int stm32_dfsdm_adc_dma_residue(struct stm32_dfsdm_adc *adc)
return 0;
}
-static irqreturn_t stm32_dfsdm_adc_trigger_handler(int irq, void *p)
-{
- struct iio_poll_func *pf = p;
- struct iio_dev *indio_dev = pf->indio_dev;
- struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
- int available = stm32_dfsdm_adc_dma_residue(adc);
-
- while (available >= indio_dev->scan_bytes) {
- u32 *buffer = (u32 *)&adc->rx_buf[adc->bufi];
-
- iio_push_to_buffers_with_timestamp(indio_dev, buffer,
- pf->timestamp);
- available -= indio_dev->scan_bytes;
- adc->bufi += indio_dev->scan_bytes;
- if (adc->bufi >= adc->buf_sz)
- adc->bufi = 0;
- }
-
- iio_trigger_notify_done(indio_dev->trig);
-
- return IRQ_HANDLED;
-}
-
static void stm32_dfsdm_dma_buffer_done(void *data)
{
struct iio_dev *indio_dev = data;
@@ -811,11 +788,6 @@ static void stm32_dfsdm_dma_buffer_done(void *data)
int available = stm32_dfsdm_adc_dma_residue(adc);
size_t old_pos;
- if (indio_dev->currentmode & INDIO_BUFFER_TRIGGERED) {
- iio_trigger_poll_chained(indio_dev->trig);
- return;
- }
-
/*
* FIXME: In Kernel interface does not support cyclic DMA buffer,and
* offers only an interface to push data samples per samples.
@@ -852,7 +824,15 @@ static void stm32_dfsdm_dma_buffer_done(void *data)
adc->bufi = 0;
old_pos = 0;
}
- /* regular iio buffer without trigger */
+ /*
+ * 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).
+ */
if (adc->dev_data->type == DFSDM_IIO)
iio_push_to_buffers(indio_dev, buffer);
}
@@ -1458,8 +1438,7 @@ static int stm32_dfsdm_adc_init(struct iio_dev *indio_dev)
}
ret = iio_triggered_buffer_setup(indio_dev,
- &iio_pollfunc_store_time,
- &stm32_dfsdm_adc_trigger_handler,
+ &iio_pollfunc_store_time, NULL,
&stm32_dfsdm_buffer_setup_ops);
if (ret) {
stm32_dfsdm_dma_release(indio_dev);
--
2.7.4