Bluetooth: Audio: Add broadcast source metadata update function

Add API to do the BAP Broadcast Source Metadata update procedure,
which updates the metadata of a broadcast source while
it is streaming.

This is also makes all checks for the "head stream" the same.

Signed-off-by: Emil Gydesen <emil.gydesen@nordicsemi.no>

include/zephyr/bluetooth/audio/audio.h

@@ -2077,7 +2077,7 @@ int bt_audio_broadcast_source_create(struct bt_audio_broadcast_source_create_par
 /** @brief Reconfigure audio broadcast source.
  *
  *  Reconfigure an audio broadcast source with a new codec and codec quality of
- *  service parameters.
+ *  service parameters. This can only be done when the source is stopped.
  *
  *  @param source      Pointer to the broadcast source
  *  @param codec       Codec configuration.
@@ -2089,6 +2089,22 @@ int bt_audio_broadcast_source_reconfig(struct bt_audio_broadcast_source *source,
 				       struct bt_codec *codec,
 				       struct bt_codec_qos *qos);
 
+/** @brief Modify the metadata of an audio broadcast source.
+ *
+ *  Modify the metadata an audio broadcast source. This can only be done when
+ *  the source is started. To update the metadata in the stopped state, use
+ *  bt_audio_broadcast_source_reconfig().
+ *
+ *  @param source      Pointer to the broadcast source.
+ *  @param meta        Metadata entries.
+ *  @param meta_count  Number of metadata entries.
+ *
+ *  @return Zero on success or (negative) error code otherwise.
+ */
+int bt_audio_broadcast_source_update_metadata(struct bt_audio_broadcast_source *source,
+					      const struct bt_codec_data meta[],
+					      size_t meta_count);
+
 /** @brief Start audio broadcast source.
  *
  *  Start an audio broadcast source with one or more audio streams.

subsys/bluetooth/audio/broadcast_source.c

@@ -765,6 +765,81 @@ int bt_audio_broadcast_source_reconfig(struct bt_audio_broadcast_source *source,
 	return 0;
 }
 
+static void broadcast_source_store_metadata(struct bt_codec *codec,
+					    const struct bt_codec_data meta[],
+					    size_t meta_count)
+{
+	size_t old_meta_count;
+
+	old_meta_count = codec->meta_count;
+
+	/* Update metadata */
+	codec->meta_count = meta_count;
+	(void)memcpy(codec->meta, meta, meta_count * sizeof(*meta));
+	if (old_meta_count > meta_count) {
+		size_t meta_count_diff = old_meta_count - meta_count;
+
+		/* If we previously had more metadata entries we reset the
+		 * data that was not overwritten by the new metadata
+		 */
+		(void)memset(&codec->meta[meta_count],
+			     0, meta_count_diff * sizeof(*meta));
+	}
+}
+
+int bt_audio_broadcast_source_update_metadata(struct bt_audio_broadcast_source *source,
+					      const struct bt_codec_data meta[],
+					      size_t meta_count)
+{
+	struct bt_audio_broadcast_subgroup *subgroup;
+	enum bt_audio_state broadcast_state;
+
+	CHECKIF(source == NULL) {
+		LOG_DBG("source is NULL");
+
+		return -EINVAL;
+	}
+
+	CHECKIF((meta == NULL && meta_count != 0) ||
+		(meta != NULL && meta_count == 0)) {
+		LOG_DBG("Invalid metadata combination: %p %zu",
+			meta, meta_count);
+
+		return -EINVAL;
+	}
+
+	CHECKIF(meta_count > CONFIG_BT_CODEC_MAX_METADATA_COUNT) {
+		LOG_DBG("Invalid meta_count: %zu (max %d)",
+			meta_count, CONFIG_BT_CODEC_MAX_METADATA_COUNT);
+
+		return -EINVAL;
+	}
+
+	for (size_t i = 0; i < meta_count; i++) {
+		CHECKIF(meta[i].data.data_len > sizeof(meta[i].value)) {
+			LOG_DBG("Invalid meta[%zu] data_len %u",
+				i, meta[i].data.data_len);
+
+			return -EINVAL;
+		}
+	}
+	broadcast_state = broadcast_source_get_state(source);
+	if (broadcast_source_get_state(source) != BT_AUDIO_EP_STATE_STREAMING) {
+		LOG_DBG("Broadcast source invalid state: %u", broadcast_state);
+
+		return -EBADMSG;
+	}
+
+	/* TODO: We should probably find a way to update the metadata
+	 * for each subgroup individually
+	 */
+	SYS_SLIST_FOR_EACH_CONTAINER(&source->subgroups, subgroup, _node) {
+		broadcast_source_store_metadata(subgroup->codec, meta, meta_count);
+	}
+
+	return 0;
+}
+
 int bt_audio_broadcast_source_start(struct bt_audio_broadcast_source *source,
 				    struct bt_le_ext_adv *adv)
 {

tests/bluetooth/bsim_bt/bsim_test_audio/src/broadcast_sink_test.c

@@ -15,6 +15,7 @@ extern enum bst_result_t bst_result;
 
 CREATE_FLAG(broadcaster_found);
 CREATE_FLAG(base_received);
+CREATE_FLAG(flag_base_metadata_updated);
 CREATE_FLAG(pa_synced);
 CREATE_FLAG(flag_syncable);
 CREATE_FLAG(pa_sync_lost);
@@ -30,6 +31,8 @@ static struct bt_audio_lc3_preset preset_16_2_1 =
 static K_SEM_DEFINE(sem_started, 0U, ARRAY_SIZE(streams));
 static K_SEM_DEFINE(sem_stopped, 0U, ARRAY_SIZE(streams));
 
+static struct bt_codec_data metadata[CONFIG_BT_CODEC_MAX_METADATA_COUNT];
+
 /* Create a mask for the maximum BIS we can sync to using the number of streams
  * we have. We add an additional 1 since the bis indexes start from 1 and not
  * 0.
@@ -76,6 +79,17 @@ static void base_recv_cb(struct bt_audio_broadcast_sink *sink,
 	uint32_t base_bis_index_bitfield = 0U;
 
 	if (TEST_FLAG(base_received)) {
+
+		if (base->subgroup_count > 0 &&
+		    memcmp(metadata, base->subgroups[0].codec.meta,
+			   sizeof(base->subgroups[0].codec.meta)) != 0) {
+
+			(void)memcpy(metadata, base->subgroups[0].codec.meta,
+				     sizeof(base->subgroups[0].codec.meta));
+
+			SET_FLAG(flag_base_metadata_updated);
+		}
+
 		return;
 	}
 
@@ -235,6 +249,10 @@ static void test_main(void)
 	printk("Waiting for data\n");
 	WAIT_FOR_FLAG(flag_received);
 
+	/* Ensure that we also see the metadata update */
+	printk("Waiting for metadata update\n");
+	WAIT_FOR_FLAG(flag_base_metadata_updated)
+
 	/* The order of PA sync lost and BIG Sync lost is irrelevant
 	 * and depend on timeout parameters. We just wait for PA first, but
 	 * either way will work.
@@ -293,6 +311,10 @@ static void test_sink_disconnect(void)
 	printk("Waiting for data\n");
 	WAIT_FOR_FLAG(flag_received);
 
+	/* Ensure that we also see the metadata update */
+	printk("Waiting for metadata update\n");
+	WAIT_FOR_FLAG(flag_base_metadata_updated)
+
 	err = bt_audio_broadcast_sink_stop(g_sink);
 	if (err != 0) {
 		FAIL("Unable to stop sink: %d", err);

tests/bluetooth/bsim_bt/bsim_test_audio/src/broadcast_source_test.c

@@ -244,6 +244,8 @@ static int stop_extended_adv(struct bt_le_ext_adv *adv)
 
 static void test_main(void)
 {
+	struct bt_codec_data new_metadata[1] =
+		BT_CODEC_LC3_CONFIG_META(BT_AUDIO_CONTEXT_TYPE_ALERTS);
 	struct bt_audio_broadcast_source *source;
 	struct bt_le_ext_adv *adv;
 	int err;
@@ -299,6 +301,18 @@ static void test_main(void)
 	/* Keeping running for a little while */
 	k_sleep(K_SECONDS(15));
 
+	/* Update metadata while streaming */
+	printk("Updating metadata\n");
+	err = bt_audio_broadcast_source_update_metadata(source, new_metadata,
+							ARRAY_SIZE(new_metadata));
+	if (err != 0) {
+		FAIL("Failed to update metadata broadcast source: %d", err);
+		return;
+	}
+
+	/* Keeping running for a little while */
+	k_sleep(K_SECONDS(5));
+
 	printk("Stopping broadcast source\n");
 	SET_FLAG(flag_stopping);
 	err = bt_audio_broadcast_source_stop(source);