drivers: video: Add video buffer state

Add a video_buf_state field to track the current state of a buffer when
it is flowing. This also helps to check whether a buffer can be safely
enqueued or dequeued, data are valid or not, etc.

Signed-off-by: Phi Bang Nguyen <[email protected]>

Author: ngphibang

drivers/video/video_common.c

@@ -69,6 +69,7 @@ struct video_buffer *video_buffer_aligned_alloc(size_t size, size_t align, k_tim
 	vbuf->buffer = block->data;
 	vbuf->size = size;
 	vbuf->bytesused = 0;
+	vbuf->state = VIDEO_BUF_STATE_DONE;
 
 	return vbuf;
 }
@@ -112,6 +113,12 @@ int video_enqueue(const struct device *dev, struct video_buffer *buf)
 		return -ENOSYS;
 	}
 
+	if (video_buf[buf->index].state != VIDEO_BUF_STATE_DONE) {
+		return -EINVAL;
+	}
+
+	video_buf[buf->index].state = VIDEO_BUF_STATE_QUEUED;
+
 	return api->enqueue(dev, &video_buf[buf->index]);
 }
 

include/zephyr/drivers/video.h

@@ -56,6 +56,22 @@ enum video_buf_type {
 	VIDEO_BUF_TYPE_OUTPUT,
 };
 
+/**
+ * @brief video_buf_state enum
+ *
+ * Current state of a video buffer.
+ * This helps to keep track of state of a buffer for debugging or to do some guard
+ * checks, e.g. prevents re-enqueuing a buffer already queued, etc.
+ */
+enum video_buf_state {
+	/** buffer queued in video subsystem and driver */
+	VIDEO_BUF_STATE_QUEUED,
+	/** buffer filled and can be dequeued by application */
+	VIDEO_BUF_STATE_DONE,
+	/** buffer returned from the driver with an error */
+	VIDEO_BUF_STATE_ERROR,
+};
+
 /**
  * @struct video_format
  * @brief Video format structure
@@ -146,6 +162,8 @@ struct video_caps {
 struct video_buffer {
 	/** type of the buffer */
 	enum video_buf_type type;
+	/** current state of the buffer */
+	enum video_buf_state state;
 	/** pointer to driver specific data. */
 	void *driver_data;
 	/** pointer to the start of the buffer. */
@@ -591,6 +609,7 @@ static inline int video_dequeue(const struct device *dev, struct video_buffer **
 				k_timeout_t timeout)
 {
 	const struct video_driver_api *api;
+	int ret;
 
 	__ASSERT_NO_MSG(dev != NULL);
 	__ASSERT_NO_MSG(buf != NULL);
@@ -600,7 +619,13 @@ static inline int video_dequeue(const struct device *dev, struct video_buffer **
 		return -ENOSYS;
 	}
 
-	return api->dequeue(dev, buf, timeout);
+	ret = api->dequeue(dev, buf, timeout);
+	
+	if (ret == 0) {
+		(*buf)->state = VIDEO_BUF_STATE_DONE;
+	}
+
+	return ret;
 }
 
 /**