1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/media/platform/stm32/stm32-dcmi.c b/drivers/media/platform/stm32/stm32-dcmi.c
index 4281f3f76ab1..f157ccbd8286 100644
--- a/drivers/media/platform/stm32/stm32-dcmi.c
+++ b/drivers/media/platform/stm32/stm32-dcmi.c
@@ -161,6 +161,9 @@ struct stm32_dcmi {
 	u32				misr;
 	int				errors_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)
@@ -291,6 +294,13 @@ static int dcmi_start_dma(struct stm32_dcmi *dcmi,
 		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,
@@ -298,6 +308,7 @@ static int dcmi_start_dma(struct stm32_dcmi *dcmi,
 	if (!desc) {
 		dev_err(dcmi->dev, "%s: DMA dmaengine_prep_slave_single failed for buffer size %zu\n",
 			__func__, buf->size);
+		mutex_unlock(&dcmi->dma_lock);
 		return -EINVAL;
 	}
 
@@ -309,9 +320,12 @@ static int dcmi_start_dma(struct stm32_dcmi *dcmi,
 	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;
@@ -690,7 +704,9 @@ static void dcmi_stop_streaming(struct vb2_queue *vq)
 	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);
 
 	clk_disable(dcmi->mclk);
 
@@ -1662,6 +1678,7 @@ static int dcmi_probe(struct platform_device *pdev)
 
 	spin_lock_init(&dcmi->irqlock);
 	mutex_init(&dcmi->lock);
+	mutex_init(&dcmi->dma_lock);
 	init_completion(&dcmi->complete);
 	INIT_LIST_HEAD(&dcmi->buffers);