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Commit e7455065 authored by Hugues Fruchet's avatar Hugues Fruchet Committed by Greg Kroah-Hartman
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media: stm32-dcmi: fix DMA corruption when stopping streaming 



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: default avatarHugues Fruchet <hugues.fruchet@st.com>
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: default avatarMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c7f92e45

drivers/media/platform/stm32/stm32-dcmi.c

+17 −0
Original line number Diff line number Diff line
@@ -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_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,
@@ -322,6 +332,7 @@ static int dcmi_start_dma(struct stm32_dcmi *dcmi, 
	if (!desc) {

		dev_err(dcmi->dev, "%s: DMA dmaengine_prep_slave_single failed for buffer 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_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;
@@ -717,7 +731,9 @@ 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);



	pm_runtime_put(dcmi->dev);
@@ -1719,6 +1735,7 @@ 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);