From: Olivier Moysan olivier.moysan@st.com
commit e2042d2936dfc84e9c600fe9b9d0039ca0e54b7d upstream.
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: 2763ea0585c9 ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/iio/adc/stm32-adc.c | 31 ++++++++++++++++++++++++++++--- 1 file changed, 28 insertions(+), 3 deletions(-)
--- a/drivers/iio/adc/stm32-adc.c +++ b/drivers/iio/adc/stm32-adc.c @@ -1311,8 +1311,30 @@ static unsigned int stm32_adc_dma_residu 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); + + while (residue >= indio_dev->scan_bytes) { + u16 *buffer = (u16 *)&adc->rx_buf[adc->bufi];
- iio_trigger_poll_chained(indio_dev->trig); + 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) @@ -1648,6 +1670,7 @@ static int stm32_adc_probe(struct platfo { struct iio_dev *indio_dev; struct device *dev = &pdev->dev; + irqreturn_t (*handler)(int irq, void *p) = NULL; struct stm32_adc *adc; int ret;
@@ -1730,9 +1753,11 @@ static int stm32_adc_probe(struct platfo if (ret < 0) goto err_clk_disable;
+ 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");