DP: add "get Latest Feeding Time" stub to sink_api

this commit adds a stubbed "get_LFT" operation to
sink_api

Stub of the function is needed because, of circular
dependency. As described, calculation of LFT requires
calculation of (next) module deadline, which requires
calculation of (next) buffer LFT

Signed-off-by: Marcin Szkudlinski <marcin.szkudlinski@intel.com>

Author: marcinszkudlinski

src/audio/buffers/audio_buffer.c

@@ -182,6 +182,14 @@ int audio_buffer_source_set_alignment_constants(struct sof_source *source,
 	return 0;
 }
 
+/**
+ * this is stub, always return Last Feeding Time - 0, meaning "NOW"
+ */
+uint32_t audio_buffer_sink_get_lft(struct sof_sink *sink)
+{
+	return 0;
+}
+
 void audio_buffer_init(struct sof_audio_buffer *buffer, uint32_t buffer_type, bool is_shared,
 		       const struct source_ops *source_ops, const struct sink_ops *sink_ops,
 		       const struct audio_buffer_ops *audio_buffer_ops,

src/audio/buffers/comp_buffer.c

@@ -178,14 +178,15 @@ APP_TASK_DATA static const struct sink_ops comp_buffer_sink_ops = {
 	.audio_set_ipc_params = audio_buffer_sink_set_ipc_params,
 	.on_audio_format_set = audio_buffer_sink_on_audio_format_set,
 	.set_alignment_constants = audio_buffer_sink_set_alignment_constants,
+	.get_lft = audio_buffer_sink_get_lft,
 };
 
 static const struct audio_buffer_ops audio_buffer_ops = {
 	.free = comp_buffer_free,
 	.reset = comp_buffer_reset,
 	.audio_set_ipc_params = comp_buffer_set_ipc_params,
 	.on_audio_format_set = comp_buffer_format_set,
-	.set_alignment_constants = comp_buffer_set_alignment_constants
+	.set_alignment_constants = comp_buffer_set_alignment_constants,
 };
 
 static struct comp_buffer *buffer_alloc_struct(void *stream_addr, size_t size,

src/audio/buffers/ring_buffer.c

@@ -273,11 +273,12 @@ static const struct sink_ops ring_buffer_sink_ops = {
 	.audio_set_ipc_params = audio_buffer_sink_set_ipc_params,
 	.on_audio_format_set = audio_buffer_sink_on_audio_format_set,
 	.set_alignment_constants = audio_buffer_sink_set_alignment_constants,
+	.get_lft = audio_buffer_sink_get_lft,
 };
 
 static const struct audio_buffer_ops audio_buffer_ops = {
 	.free = ring_buffer_free,
-	.reset = ring_buffer_reset
+	.reset = ring_buffer_reset,
 };
 
 struct ring_buffer *ring_buffer_create(struct comp_dev *dev, size_t min_available,

src/include/module/audio/sink_api.h

@@ -77,6 +77,12 @@ struct sink_ops {
 	 */
 	int (*commit_buffer)(struct sof_sink *sink, size_t commit_size);
 
+	/**
+	 * get latest feeding time for this sink, result is a number of microseconds since "NOW"
+	 * where "now" means a start of last LL cycle, as described in zephyr_dp_schedule.c
+	 */
+	uint32_t (*get_lft)(struct sof_sink *sink);
+
 	/**
 	 * OPTIONAL: Notification to the sink implementation about changes in audio format
 	 *
@@ -348,4 +354,9 @@ static inline struct processing_module *sink_get_bound_module(struct sof_sink *s
 	return sink->bound_module;
 }
 
+static inline uint32_t sink_get_last_feeding_time(struct sof_sink *sink)
+{
+	return sink->ops->get_lft(sink);
+}
+
 #endif /* __MODULE_AUDIO_SINK_API_H__ */

src/include/sof/audio/audio_buffer.h

@@ -337,5 +337,6 @@ int audio_buffer_sink_on_audio_format_set(struct sof_sink *sink);
 int audio_buffer_sink_set_alignment_constants(struct sof_sink *sink,
 					      const uint32_t byte_align,
 					      const uint32_t frame_align_req);
+uint32_t audio_buffer_sink_get_lft(struct sof_sink *sink);
 
 #endif /* __SOF_AUDIO_BUFFER__ */