pipeline param negotiation

src/audio/pipeline.c

@@ -169,6 +169,10 @@ static int pipeline_for_each_comp(struct comp_dev *current,
 	list_for_item(clist, buffer_list) {
  buffer = buffer_from_list(clist, struct comp_buffer, dir);
 
+ /* don't go back to the buffer which already walked */
+ if (buffer->walking)
+ continue;
+
  /* execute operation on buffer */
  if (ctx->buff_func)
  ctx->buff_func(buffer, ctx->buff_data);
@@ -182,8 +186,10 @@ static int pipeline_for_each_comp(struct comp_dev *current,
 
  /* continue further */
  if (ctx->comp_func) {
+ buffer->walking = true;
  int err = ctx->comp_func(buffer_comp, buffer,
  ctx, dir);
+ buffer->walking = false;
  if (err < 0)
  return err;
  }
@@ -383,11 +389,64 @@ static int pipeline_comp_hw_params(struct comp_dev *current,
 	return 0;
 }
 
+static int pipeline_comp_params_neg(struct comp_dev *current,
+ struct comp_buffer *calling_buf,
+ struct pipeline_walk_context *ctx,
+ int dir)
+{
+	struct pipeline_data *ppl_data = ctx->comp_data;
+	uint32_t flags = 0;
+	int err = 0;
+
+	pipe_dbg(ppl_data->p, "pipeline_comp_params_neg(), current->comp.id = %u, dir = %u",
+ dev_comp_id(current), dir);
+
+	/* check if 'current' is already configured */
+	if (current->state != COMP_STATE_INIT &&
+ current->state != COMP_STATE_READY) {
+ /* return 0 if params matches */
+ if (buffer_params_match(calling_buf,
+ &ppl_data->params->params,
+ BUFF_PARAMS_FRAME_FMT |
+ BUFF_PARAMS_RATE))
+ return 0;
+ /*
+ * the param is conflict with an active pipeline,
+ * drop an error and reject the .params() command.
+ */
+ pipe_err(ppl_data->p, "pipeline_comp_params_neg(): params conflict with existed active pipeline!");
+ return -EINVAL;
+	}
+
+	/*
+ * Negotiation only happen when the current component has > 1
+ * source or sink, we are propagating the params to branched
+ * buffers, and the subsequent component's .params() or .prepare()
+ * should be responsible for calibrating if needed. For example,
+ * a component who has different channels input/output buffers
+ * should explicitly configure the channels of the branched buffers.
+ */
+	if (calling_buf) {
+ buffer_lock(calling_buf, &flags);
+ err = buffer_set_params(calling_buf,
+ &ppl_data->params->params,
+ BUFFER_UPDATE_FORCE);
+ buffer_unlock(calling_buf, flags);
+	}
+
+	return err;
+}
+
 static int pipeline_comp_params(struct comp_dev *current,
  struct comp_buffer *calling_buf,
  struct pipeline_walk_context *ctx, int dir)
 {
 	struct pipeline_data *ppl_data = ctx->comp_data;
+	struct pipeline_walk_context param_neg_ctx = {
+ .comp_func = pipeline_comp_params_neg,
+ .comp_data = ppl_data,
+ .skip_incomplete = true,
+	};
 	int stream_direction = ppl_data->params->params.direction;
 	int end_type;
 	int err;
@@ -421,6 +480,11 @@ static int pipeline_comp_params(struct comp_dev *current,
 	if (current->state == COMP_STATE_ACTIVE)
  return 0;
 
+	/* do params negotiation with other branches(opposite direction) */
+	err = pipeline_for_each_comp(current, &param_neg_ctx, !dir);
+	if (err < 0 || err == PPL_STATUS_PATH_STOP)
+ return err;
+
 	/* set comp direction */
 	current->direction = ppl_data->params->params.direction;
 

src/include/sof/audio/buffer.h

@@ -111,6 +111,7 @@ struct comp_buffer {
 	uint16_t chmap[SOF_IPC_MAX_CHANNELS];	/**< channel map - SOF_CHMAP_ */
 
 	bool hw_params_configured; /**< indicates whether hw params were set */
+	bool walking;	/**< indicates if the buffer is being walking */
 };
 
 struct buffer_cb_transact {
@@ -295,4 +296,25 @@ static inline int buffer_set_params(struct comp_buffer *buffer,
 	return 0;
 }
 
+static inline bool buffer_params_match(struct comp_buffer *buffer,
+ struct sof_ipc_stream_params *params,
+ uint32_t flag)
+{
+	assert(params && buffer);
+
+	if ((flag & BUFF_PARAMS_FRAME_FMT) &&
+ buffer->stream.frame_fmt != params->frame_fmt)
+ return false;
+
+	if ((flag & BUFF_PARAMS_RATE) &&
+ buffer->stream.rate != params->rate)
+ return false;
+
+	if ((flag & BUFF_PARAMS_CHANNELS) &&
+ buffer->stream.channels != params->channels)
+ return false;
+
+	return true;
+}
+
 #endif /* __SOF_AUDIO_BUFFER_H__ */