module: audio: add component state accessors to sink and source APIs

Add optional get_state callbacks and accessors for querying upstream
and downstream component states. Return COMP_STATE_NOT_EXIST
when unavailable.

Signed-off-by: Piotr Hoppe <piotr.hoppe@intel.com>

Author: piotrhoppeintel

src/include/module/audio/sink_api.h

@@ -83,6 +83,13 @@ struct sink_ops {
 	 */
 	uint32_t (*get_lft)(struct sof_sink *sink);
 
+	/**
+	 * OPTIONAL: get the state of the component consuming data from this sink
+	 *
+	 * see comment of sink_get_state()
+	 */
+	int (*get_state)(struct sof_sink *sink);
+
 	/**
 	 * OPTIONAL: Notification to the sink implementation about changes in audio format
 	 *
@@ -318,6 +325,25 @@ static inline uint32_t sink_get_pipeline_id(struct sof_sink *sink)
 	return sink->audio_stream_params->pipeline_id;
 }
 
+/**
+ * @brief get the state of the component consuming data from this sink
+ *
+ * This allows a data producer to query the state of its downstream consumer
+ * without reaching into the underlying buffer implementation.
+ *
+ * @param sink a sink to be checked
+ *
+ * @return state of the consuming component, or COMP_STATE_NOT_EXIST (0) if there
+ *         is no connected consumer or the sink implementation does not track it
+ */
+static inline int sink_get_state(struct sof_sink *sink)
+{
+	if (!sink->ops->get_state)
+		return 0; /* COMP_STATE_NOT_EXIST */
+
+	return sink->ops->get_state(sink);
+}
+
 /**
  * @brief hook to be called when a module connects to the API
  *

src/include/module/audio/source_api.h

@@ -79,6 +79,13 @@ struct source_ops {
 	 */
 	int (*release_data)(struct sof_source *source, size_t free_size);
 
+	/**
+	 * OPTIONAL: get the state of the component producing data to this source
+	 *
+	 * see comment of source_get_comp_state()
+	 */
+	int (*get_state)(struct sof_source *source);
+
 	/**
 	 * OPTIONAL: Notification to the source implementation about changes in audio format
 	 *
@@ -341,6 +348,25 @@ static inline enum sof_audio_buffer_state source_get_state(const struct sof_sour
 	return source->audio_stream_params->state;
 }
 
+/**
+ * @brief get the state of the component producing data to this source
+ *
+ * This allows a data consumer to query the state of its upstream producer
+ * without reaching into the underlying buffer implementation.
+ *
+ * @param source a source to be checked
+ *
+ * @return state of the producing component, or COMP_STATE_NOT_EXIST (0) if there
+ *         is no connected producer or the source implementation does not track it
+ */
+static inline int source_get_comp_state(struct sof_source *source)
+{
+	if (!source->ops->get_state)
+		return 0; /* COMP_STATE_NOT_EXIST */
+
+	return source->ops->get_state(source);
+}
+
 static inline uint32_t source_align_frames_round_up(struct sof_source *source, uint32_t frames)
 {
 	uint16_t align = source->audio_stream_params->align_frame_cnt;