From: Hugues Fruchet hugues.fruchet@st.com
commit b3ce6f6ff3c260ee53b0f2236e5fd950d46957da upstream.
Avoid call of dmaengine_terminate_all() between dmaengine_prep_slave_single() and dmaengine_submit() by locking the whole DMA submission sequence.
Signed-off-by: Hugues Fruchet hugues.fruchet@st.com Signed-off-by: Hans Verkuil hverkuil-cisco@xs4all.nl Signed-off-by: Mauro Carvalho Chehab mchehab+samsung@kernel.org Signed-off-by: Mathieu Poirier mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/media/platform/stm32/stm32-dcmi.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
--- a/drivers/media/platform/stm32/stm32-dcmi.c +++ b/drivers/media/platform/stm32/stm32-dcmi.c @@ -164,6 +164,9 @@ struct stm32_dcmi { int errors_count; int overrun_count; int buffers_count; + + /* Ensure DMA operations atomicity */ + struct mutex dma_lock; };
static inline struct stm32_dcmi *notifier_to_dcmi(struct v4l2_async_notifier *n) @@ -314,6 +317,13 @@ static int dcmi_start_dma(struct stm32_d return ret; }
+ /* + * Avoid call of dmaengine_terminate_all() between + * dmaengine_prep_slave_single() and dmaengine_submit() + * by locking the whole DMA submission sequence + */ + mutex_lock(&dcmi->dma_lock); + /* Prepare a DMA transaction */ desc = dmaengine_prep_slave_single(dcmi->dma_chan, buf->paddr, buf->size, @@ -322,6 +332,7 @@ static int dcmi_start_dma(struct stm32_d if (!desc) { dev_err(dcmi->dev, "%s: DMA dmaengine_prep_slave_single failed for buffer phy=%pad size=%zu\n", __func__, &buf->paddr, buf->size); + mutex_unlock(&dcmi->dma_lock); return -EINVAL; }
@@ -333,9 +344,12 @@ static int dcmi_start_dma(struct stm32_d dcmi->dma_cookie = dmaengine_submit(desc); if (dma_submit_error(dcmi->dma_cookie)) { dev_err(dcmi->dev, "%s: DMA submission failed\n", __func__); + mutex_unlock(&dcmi->dma_lock); return -ENXIO; }
+ mutex_unlock(&dcmi->dma_lock); + dma_async_issue_pending(dcmi->dma_chan);
return 0; @@ -717,7 +731,9 @@ static void dcmi_stop_streaming(struct v spin_unlock_irq(&dcmi->irqlock);
/* Stop all pending DMA operations */ + mutex_lock(&dcmi->dma_lock); dmaengine_terminate_all(dcmi->dma_chan); + mutex_unlock(&dcmi->dma_lock);
pm_runtime_put(dcmi->dev);
@@ -1719,6 +1735,7 @@ static int dcmi_probe(struct platform_de
spin_lock_init(&dcmi->irqlock); mutex_init(&dcmi->lock); + mutex_init(&dcmi->dma_lock); init_completion(&dcmi->complete); INIT_LIST_HEAD(&dcmi->buffers);