ipc4: mixin & mixout: refine mixer behavior for state change

For ipc3 mixer, pipeline will stop at mixer for trigger
and prepare cases, but it is not fit for ipc4, since there
are more than 1 pipeline in the pcm stream, one for mixer and
following components and another one is for front-end components.

This patch divides prepare & trigger function to two parts: common
shared part and part for mixer.

Signed-off-by: Rander Wang <[email protected]>

src/audio/mixer.c

@@ -234,13 +234,11 @@ static int mixer_source_status_count(struct comp_dev *mixer, uint32_t status)
 }
 
 /* used to pass standard and bespoke commands (with data) to component */
-static int mixer_trigger(struct comp_dev *dev, int cmd)
+static int mixer_trigger_common(struct comp_dev *dev, int cmd)
 {
 	int dir = dev->pipeline->source_comp->direction;
 	int ret;
 
-	comp_dbg(dev, "mixer_trigger()");
-
 	/*
 	 * This works around an unclear and apparently needlessly complicated
 	 * mixer state machine.
@@ -255,11 +253,8 @@ static int mixer_trigger(struct comp_dev *dev, int cmd)
 			/* Mixer and everything downstream is active */
 			dev->state = COMP_STATE_ACTIVE;
 			break;
-		case COMP_TRIGGER_PRE_START:
-			/* Mixer and downstream components might or might not be active */
-			if (mixer_source_status_count(dev, COMP_STATE_ACTIVE) ||
-			    mixer_source_status_count(dev, COMP_STATE_PAUSED))
-				return PPL_STATUS_PATH_STOP;
+		default:
+			break;
 		}
 
 		comp_writeback(dev);
@@ -418,13 +413,10 @@ static int mixer_reset(struct comp_dev *dev)
  * We should also make sure that we propagate the prepare call to downstream
  * if downstream is not currently active.
  */
-static int mixer_prepare(struct comp_dev *dev)
+static int mixer_prepare_common(struct comp_dev *dev)
 {
 	struct mixer_data *md = comp_get_drvdata(dev);
-	struct list_item *blist;
-	struct comp_buffer *source;
 	struct comp_buffer *sink;
-	int downstream = 0;
 	int ret;
 
 	comp_dbg(dev, "mixer_prepare()");
@@ -464,22 +456,69 @@ static int mixer_prepare(struct comp_dev *dev)
 			return PPL_STATUS_PATH_STOP;
 	}
 
+	return 0;
+}
+
+/* In IPC3 the simplest pipeline with mixer will like
+ * host1 -> mixer -> volume -> dai, pipeline 1.
+ *           |
+ * host2 ---- pipeline 2
+ *
+ * For IPC4, it will be like
+ * copier1(host) -> mixin1 ----> mixout(mixer) -> gain(volume) -> copier2(dai)
+ *    pipeline 1                   |       pipline 2
+ * copier3(host) -> mixin2 -------  pipeline 3
+ *
+ * mixin and mixout will be in different pipelines.
+ * Now we combine mixin and mixout into mixer, but
+ * the pipelines count is unchange. Ipc4 pipeline
+ * can't be stopped at mixer component since pipeline
+ * design is different, or gain and copier2 will not
+ * be triggered. Since mixer will be in a different
+ * pipeline other than host pipeline, it will not be
+ * triggered second time.
+ */
+#if CONFIG_IPC_MAJOR_3
+static int mixer_trigger(struct comp_dev *dev, int cmd)
+{
+	int dir = dev->pipeline->source_comp->direction;
+
+	comp_dbg(dev, "mixer_trigger()");
+
+	if (dir == SOF_IPC_STREAM_PLAYBACK && cmd == COMP_TRIGGER_PRE_START)
+		/* Mixer and downstream components might or might not be active */
+		if (mixer_source_status_count(dev, COMP_STATE_ACTIVE) ||
+		    mixer_source_status_count(dev, COMP_STATE_PAUSED))
+			return PPL_STATUS_PATH_STOP;
+
+	return mixer_trigger_common(dev, cmd);
+}
+
+static int mixer_prepare(struct comp_dev *dev)
+{
+	struct comp_buffer *source;
+	struct list_item *blist;
+	int ret;
+
+	ret = mixer_prepare_common(dev);
+	if (ret)
+		return ret;
+
 	/* check each mixer source state */
 	list_for_item(blist, &dev->bsource_list) {
 		source = container_of(blist, struct comp_buffer, sink_list);
 
 		/* only prepare downstream if we have no active sources */
 		if (source->source->state == COMP_STATE_PAUSED ||
 		    source->source->state == COMP_STATE_ACTIVE) {
-			downstream = 1;
+			return PPL_STATUS_PATH_STOP;
 		}
 	}
 
 	/* prepare downstream */
-	return downstream;
+	return 0;
 }
 
-#if CONFIG_IPC_MAJOR_3
 static const struct comp_driver comp_mixer = {
 	.type	= SOF_COMP_MIXER,
 	.uid	= SOF_RT_UUID(mixer_uuid),
@@ -652,8 +691,8 @@ static const struct comp_driver comp_mixer = {
 		.create		= mixinout_new,
 		.free		= mixer_free,
 		.params		= mixout_params,
-		.prepare	= mixer_prepare,
-		.trigger	= mixer_trigger,
+		.prepare	= mixer_prepare_common,
+		.trigger	= mixer_trigger_common,
 		.copy		= mixer_copy,
 		.reset		= mixer_reset,
 	},