google_rtc_audio_processing: Clean up prepare() method

The prepare step was missing some checks, and doing others in a
non-orthogonal way.  Clean it up so we can be sure it validates the
sample format, channel count and rate of each of the three connected
streams.

Signed-off-by: Andy Ross <andyross@google.com>

src/audio/google/google_rtc_audio_processing.c

@@ -518,6 +518,22 @@ static int google_rtc_audio_processing_free(struct processing_module *mod)
 	return 0;
 }
 
+static bool is_ref_buffer(struct comp_dev *dev, struct comp_buffer *b)
+{
+#if CONFIG_IPC_MAJOR_4
+	return IPC4_SINK_QUEUE_ID(buf_get_id(b)) == SOF_AEC_FEEDBACK_QUEUE_ID;
+#else
+	return b->source->pipeline->pipeline_id != dev->pipeline->pipeline_id;
+#endif
+}
+
+static enum sof_ipc_frame bits_fmt(int bits)
+{
+	if (bits == 32)
+		return SOF_IPC_FRAME_S32_LE;
+	return SOF_IPC_FRAME_S16_LE;
+}
+
 static int google_rtc_audio_processing_prepare(struct processing_module *mod,
 					       struct sof_source **sources,
 					       int num_of_sources,
@@ -528,87 +544,84 @@ static int google_rtc_audio_processing_prepare(struct processing_module *mod,
 	struct google_rtc_audio_processing_comp_data *cd = module_get_private_data(mod);
 	struct list_item *source_buffer_list_item;
 	struct comp_buffer *output;
-	unsigned int aec_channels = 0, frame_fmt, rate;
-	int microphone_stream_channels = 0;
-	int output_stream_channels;
-	int ret;
-	int i = 0;
+	int ret = 0, i = 0;
 
 	comp_info(dev, "google_rtc_audio_processing_prepare()");
 
 	/* searching for stream and feedback source buffers */
 	list_for_item(source_buffer_list_item, &dev->bsource_list) {
 		struct comp_buffer *source = container_of(source_buffer_list_item,
 							  struct comp_buffer, sink_list);
-#if CONFIG_IPC_MAJOR_4
-		if (IPC4_SINK_QUEUE_ID(buf_get_id(source)) ==
-			SOF_AEC_FEEDBACK_QUEUE_ID) {
-#else
-		if (source->source->pipeline->pipeline_id != dev->pipeline->pipeline_id) {
-#endif
+		if (is_ref_buffer(dev, source)) {
 			cd->aec_reference_source = i;
 			cd->ref_comp_buffer = source;
-			aec_channels = audio_stream_get_channels(&source->stream);
-			comp_dbg(dev, "reference index = %d, channels = %d", i, aec_channels);
 		} else {
 			cd->raw_microphone_source = i;
-			microphone_stream_channels = audio_stream_get_channels(&source->stream);
-			comp_dbg(dev, "microphone index = %d, channels = %d", i,
-				 microphone_stream_channels);
 		}
-
-		audio_stream_init_alignment_constants(1, 1, &source->stream);
 		i++;
 	}
-
 	output = list_first_item(&dev->bsink_list, struct comp_buffer, source_list);
 
-	/* On some platform the playback output is left right left right due to a crossover
-	 * later on the signal processing chain. That makes the aec_reference be 4 channels
-	 * and the AEC should only use the 2 first.
+	/* Validate channel, format and rate on each of our three
+	 * inputs.  All much match our build-time configuration, AEC
+	 * does not handle dynamic stream formats.
 	 */
-	if (cd->num_aec_reference_channels > aec_channels) {
-		comp_err(dev, "unsupported number of AEC reference channels: %d",
-			 aec_channels);
-		return -EINVAL;
+	int ref_fmt = source_get_frm_fmt(sources[cd->aec_reference_source]);
+	int ref_chan = source_get_channels(sources[cd->aec_reference_source]);
+	int ref_rate = source_get_rate(sources[cd->aec_reference_source]);
+
+	int mic_fmt = source_get_frm_fmt(sources[cd->raw_microphone_source]);
+	int mic_chan = source_get_channels(sources[cd->raw_microphone_source]);
+	int mic_rate = source_get_rate(sources[cd->raw_microphone_source]);
+
+	int out_fmt = sink_get_frm_fmt(sinks[0]);
+	int out_chan = sink_get_channels(sinks[0]);
+	int out_rate = sink_get_rate(sinks[0]);
+
+	/* Too many channels is a soft failure, AEC treats only the first N */
+	if (ref_chan > REF_CHAN_MAX)
+		comp_warn(dev, "Too many ref channels: %d, truncating to %d",
+			  ref_chan, REF_CHAN_MAX);
+	if (mic_chan > MIC_CHAN_MAX)
+		comp_warn(dev, "Too many mic channels: %d, truncating to %d",
+			  mic_chan, MIC_CHAN_MAX);
+
+	if (out_chan != mic_chan) {
+		comp_err(dev, "Input/output mic channel mismatch");
+		ret = -EINVAL;
 	}
 
-	audio_stream_init_alignment_constants(1, 1, &output->stream);
-	frame_fmt = audio_stream_get_frm_fmt(&output->stream);
-	rate = audio_stream_get_rate(&output->stream);
-	output_stream_channels = audio_stream_get_channels(&output->stream);
-
-	if (microphone_stream_channels != output_stream_channels)
-		return -EINVAL;
+	if (ref_rate != mic_rate || ref_rate != out_rate ||
+	    ref_rate != CONFIG_COMP_GOOGLE_RTC_AUDIO_PROCESSING_SAMPLE_RATE_HZ) {
+		comp_err(dev, "Incorrect source/sink sample rate, expect %d\n",
+			 CONFIG_COMP_GOOGLE_RTC_AUDIO_PROCESSING_SAMPLE_RATE_HZ);
+		ret = -EINVAL;
+	}
 
-	if (microphone_stream_channels > MIC_CHAN_MAX) {
-		comp_warn(dev, "Too many mic channels: %d (max %d), truncating",
-			  microphone_stream_channels, MIC_CHAN_MAX);
+	if (ref_fmt != bits_fmt(CONFIG_GOOGLE_RTC_AUDIO_PROCESSING_REF_BITS)) {
+		comp_err(dev, "Reference stream must be %d bit samples\n",
+			 CONFIG_GOOGLE_RTC_AUDIO_PROCESSING_REF_BITS);
+		ret = -EINVAL;
 	}
 
-	switch (frame_fmt) {
-#if CONFIG_FORMAT_S16LE
-	case SOF_IPC_FRAME_S16_LE:
-		break;
-#endif /* CONFIG_FORMAT_S16LE */
-	default:
-		comp_err(dev, "unsupported data format: %d", frame_fmt);
-		return -EINVAL;
+	if (mic_fmt != bits_fmt(CONFIG_GOOGLE_RTC_AUDIO_PROCESSING_MIC_BITS)) {
+		comp_err(dev, "Mic stream must be %d bit samples\n",
+			 CONFIG_GOOGLE_RTC_AUDIO_PROCESSING_MIC_BITS);
+		ret = -EINVAL;
 	}
 
-	if (rate != CONFIG_COMP_GOOGLE_RTC_AUDIO_PROCESSING_SAMPLE_RATE_HZ) {
-		comp_err(dev, "unsupported samplerate: %d", rate);
-		return -EINVAL;
+	if (mic_fmt != out_fmt) {
+		comp_err(dev, "Mismatched in/out frame format");
+		ret = -EINVAL;
 	}
 
 	/* Blobs sent during COMP_STATE_READY is assigned to blob_handler->data
 	 * directly, so comp_is_new_data_blob_available always returns false.
 	 */
-	ret = google_rtc_audio_processing_reconfigure(mod);
-	if (ret)
-		return ret;
+	if (ret == 0)
+		ret = google_rtc_audio_processing_reconfigure(mod);
 
-	return 0;
+	return ret;
 }
 
 static int trigger_handler(struct processing_module *mod, int cmd)