media: v4l2-mem2mem: handle draining, stopped and next-buf-is-last states

Since the draining and stop phase of the HW decoder mem2mem bahaviour is
now clearly defined, we can move handling of the following states to the
common v4l2-mem2mem core code:
- draining
- stopped
- next-buf-is-last

By introducing the following v4l2-mem2mem APIs:
- v4l2_m2m_encoder_cmd/v4l2_m2m_ioctl_encoder_cmd to handle start/stop command
- v4l2_m2m_decoder_cmd/v4l2_m2m_ioctl_decoder_cmd to handle start/stop command
- v4l2_m2m_update_start_streaming_state to update state on start of streaming
of the de/encoder queue
- v4l2_m2m_update_stop_streaming_state to update state on stop of streaming
of the de/encoder queue
- v4l2_m2m_last_buffer_done to make the current dest buffer as the last one

And inline helpers:
- v4l2_m2m_mark_stopped to mark the de/encoding process as stopped
- v4l2_m2m_clear_state to clear the de/encoding state
- v4l2_m2m_dst_buf_is_last to detect the current dequeued dst_buf is the last
- v4l2_m2m_has_stopped to detect the de/encoding stopped state
- v4l2_m2m_is_last_draining_src_buf to detect the current source buffer should
 be the last processing before stopping the de/encoding process

The special next-buf-is-last when min_buffers != 1 case is also handled
in v4l2_m2m_qbuf() by reusing the other introduced APIs.

This state management has been stolen from the vicodec implementation,
and is no-op for drivers not calling the v4l2_m2m_encoder_cmd or
v4l2_m2m_decoder_cmd and v4l2_m2m_update_start/stop_streaming_state.

The vicodec will be the first one to be converted as an example.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

1 files changed, 133 insertions, 0 deletions

diff --git a/include/media/v4l2-mem2mem.h b/include/media/v4l2-mem2mem.h
index 1d85e24791e4..98753f00df7e 100644
--- a/include/media/v4l2-mem2mem.h
+++ b/include/media/v4l2-mem2mem.h
@@ -80,6 +80,10 @@ struct v4l2_m2m_queue_ctx {
  *		for an existing frame. This is always true unless
  *		V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF is set, which
  *		indicates slicing support.
+ * @is_draining: indicates device is in draining phase
+ * @last_src_buf: indicate the last source buffer for draining
+ * @next_buf_last: next capture queud buffer will be tagged as last
+ * @has_stopped: indicate the device has been stopped
  * @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
@@ -98,6 +102,11 @@ struct v4l2_m2m_ctx {
 
 	bool				new_frame;
 
+	bool				is_draining;
+	struct vb2_v4l2_buffer		*last_src_buf;
+	bool				next_buf_last;
+	bool				has_stopped;
+
 	/* internal use only */
 	struct v4l2_m2m_dev		*m2m_dev;
 
@@ -216,6 +225,86 @@ v4l2_m2m_buf_done(struct vb2_v4l2_buffer *buf, enum vb2_buffer_state state)
 }
 
 /**
+ * v4l2_m2m_clear_state() - clear encoding/decoding state
+ *
+ * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
+ */
+static inline void
+v4l2_m2m_clear_state(struct v4l2_m2m_ctx *m2m_ctx)
+{
+	m2m_ctx->next_buf_last = false;
+	m2m_ctx->is_draining = false;
+	m2m_ctx->has_stopped = false;
+}
+
+/**
+ * v4l2_m2m_mark_stopped() - set current encoding/decoding state as stopped
+ *
+ * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
+ */
+static inline void
+v4l2_m2m_mark_stopped(struct v4l2_m2m_ctx *m2m_ctx)
+{
+	m2m_ctx->next_buf_last = false;
+	m2m_ctx->is_draining = false;
+	m2m_ctx->has_stopped = true;
+}
+
+/**
+ * v4l2_m2m_dst_buf_is_last() - return the current encoding/decoding session
+ * draining management state of next queued capture buffer
+ *
+ * This last capture buffer should be tagged with V4L2_BUF_FLAG_LAST to notify
+ * the end of the capture session.
+ *
+ * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
+ */
+static inline bool
+v4l2_m2m_dst_buf_is_last(struct v4l2_m2m_ctx *m2m_ctx)
+{
+	return m2m_ctx->is_draining && m2m_ctx->next_buf_last;
+}
+
+/**
+ * v4l2_m2m_has_stopped() - return the current encoding/decoding session
+ * stopped state
+ *
+ * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
+ */
+static inline bool
+v4l2_m2m_has_stopped(struct v4l2_m2m_ctx *m2m_ctx)
+{
+	return m2m_ctx->has_stopped;
+}
+
+/**
+ * v4l2_m2m_is_last_draining_src_buf() - return the output buffer draining
+ * state in the current encoding/decoding session
+ *
+ * This will identify the last output buffer queued before a session stop
+ * was required, leading to an actual encoding/decoding session stop state
+ * in the encoding/decoding process after being processed.
+ *
+ * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
+ * @vbuf: pointer to struct &v4l2_buffer
+ */
+static inline bool
+v4l2_m2m_is_last_draining_src_buf(struct v4l2_m2m_ctx *m2m_ctx,
+				  struct vb2_v4l2_buffer *vbuf)
+{
+	return m2m_ctx->is_draining && vbuf == m2m_ctx->last_src_buf;
+}
+
+/**
+ * v4l2_m2m_last_buffer_done() - marks the buffer with LAST flag and DONE
+ *
+ * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
+ * @vbuf: pointer to struct &v4l2_buffer
+ */
+void v4l2_m2m_last_buffer_done(struct v4l2_m2m_ctx *m2m_ctx,
+			       struct vb2_v4l2_buffer *vbuf);
+
+/**
  * v4l2_m2m_reqbufs() - multi-queue-aware REQBUFS multiplexer
  *
  * @file: pointer to struct &file
@@ -313,6 +402,46 @@ int v4l2_m2m_streamoff(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 		       enum v4l2_buf_type type);
 
 /**
+ * v4l2_m2m_update_start_streaming_state() - update the encoding/decoding
+ * session state when a start of streaming of a video queue is requested
+ *
+ * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
+ * @q: queue
+ */
+void v4l2_m2m_update_start_streaming_state(struct v4l2_m2m_ctx *m2m_ctx,
+					   struct vb2_queue *q);
+
+/**
+ * v4l2_m2m_update_stop_streaming_state() -  update the encoding/decoding
+ * session state when a stop of streaming of a video queue is requested
+ *
+ * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
+ * @q: queue
+ */
+void v4l2_m2m_update_stop_streaming_state(struct v4l2_m2m_ctx *m2m_ctx,
+					  struct vb2_queue *q);
+
+/**
+ * v4l2_m2m_encoder_cmd() - execute an encoder command
+ *
+ * @file: pointer to struct &file
+ * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
+ * @ec: pointer to the encoder command
+ */
+int v4l2_m2m_encoder_cmd(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
+			 struct v4l2_encoder_cmd *ec);
+
+/**
+ * v4l2_m2m_decoder_cmd() - execute a decoder command
+ *
+ * @file: pointer to struct &file
+ * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
+ * @dc: pointer to the decoder command
+ */
+int v4l2_m2m_decoder_cmd(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
+			 struct v4l2_decoder_cmd *dc);
+
+/**
  * v4l2_m2m_poll() - poll replacement, for destination buffers only
  *
  * @file: pointer to struct &file
@@ -704,6 +833,10 @@ int v4l2_m2m_ioctl_streamon(struct file *file, void *fh,
 				enum v4l2_buf_type type);
 int v4l2_m2m_ioctl_streamoff(struct file *file, void *fh,
 				enum v4l2_buf_type type);
+int v4l2_m2m_ioctl_encoder_cmd(struct file *file, void *fh,
+			       struct v4l2_encoder_cmd *ec);
+int v4l2_m2m_ioctl_decoder_cmd(struct file *file, void *fh,
+			       struct v4l2_decoder_cmd *dc);
 int v4l2_m2m_ioctl_try_encoder_cmd(struct file *file, void *fh,
 				   struct v4l2_encoder_cmd *ec);
 int v4l2_m2m_ioctl_try_decoder_cmd(struct file *file, void *fh,