media: v4l2-mem2mem: add new_frame detection

Drivers that support VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF
typically want to know if a new frame is started (i.e. the first
slice is about to be processed). Add a new_frame bool to v4l2_m2m_ctx
and set it accordingly.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/v4l2-core/v4l2-mem2mem.c

@@ -319,8 +319,10 @@ static void __v4l2_m2m_try_queue(struct v4l2_m2m_dev *m2m_dev,
 		goto job_unlock;
 	}
 
-	if (src && dst &&
-	    dst->is_held && dst->vb2_buf.copied_timestamp &&
+	m2m_ctx->new_frame = true;
+
+	if (src && dst && dst->is_held &&
+	    dst->vb2_buf.copied_timestamp &&
 	    dst->vb2_buf.timestamp != src->vb2_buf.timestamp) {
 		dst->is_held = false;
 		v4l2_m2m_dst_buf_remove(m2m_ctx);
@@ -333,6 +335,11 @@ static void __v4l2_m2m_try_queue(struct v4l2_m2m_dev *m2m_dev,
 		}
 	}
 
+	if (src && dst && (m2m_ctx->cap_q_ctx.q.subsystem_flags &
+			   VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF))
+		m2m_ctx->new_frame = !dst->vb2_buf.copied_timestamp ||
+			dst->vb2_buf.timestamp != src->vb2_buf.timestamp;
+
 	if (m2m_dev->m2m_ops->job_ready
 		&& (!m2m_dev->m2m_ops->job_ready(m2m_ctx->priv))) {
 		dprintk("Driver not ready\n");

include/media/v4l2-mem2mem.h

@@ -75,6 +75,11 @@ struct v4l2_m2m_queue_ctx {
  * struct v4l2_m2m_ctx - Memory to memory context structure
  *
  * @q_lock: struct &mutex lock
+ * @new_frame: valid in the device_run callback: if true, then this
+ *		starts a new frame; if false, then this is a new slice
+ *		for an existing frame. This is always true unless
+ *		V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF is set, which
+ *		indicates slicing support.
  * @m2m_dev: opaque pointer to the internal data to handle M2M context
  * @cap_q_ctx: Capture (output to memory) queue context
  * @out_q_ctx: Output (input from memory) queue context
@@ -91,6 +96,8 @@ struct v4l2_m2m_ctx {
 	/* optional cap/out vb2 queues lock */
 	struct mutex			*q_lock;
 
+	bool				new_frame;
+
 	/* internal use only */
 	struct v4l2_m2m_dev		*m2m_dev;