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iio: adc: stm32-adc: fix sleep in atomic context

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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.

Fixes: 2763ea0585 ("iio: adc: stm32: add optional dma support")
Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Olivier Moysan 2020-03-09 11:02:12 +01:00 committed by Jonathan Cameron
parent 28535877ac
commit e2042d2936
1 changed files with 28 additions and 3 deletions
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31
drivers/iio/adc/stm32-adc.c
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@ -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);
iio_trigger_poll_chained(indio_dev->trig);
/*
* 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);
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");