Bluetooth: BAP: Overwrite Receive State in the Scan Delegator

Kconfig option BT_BAP_SCAN_DELEGATOR_OVERWRITE_OLDEST
allows the Scan Delegator to overwrite the oldest inactive
receive state if there aren't any free receive states.

A inactive receive state is a receive state that has neither a
Periodic Advertising or Broadcast Isochronous Group (BIG) sync.

There is also a recv_state_add_fail callback function added
which can notify an application if all receive states
are not inactive and can't be freed.

Signed-off-by: Paul Mulligan <[email protected]>

include/zephyr/bluetooth/audio/bap.h

@@ -317,6 +317,26 @@ struct bt_bap_scan_delegator_recv_state {
 };
 
 struct bt_bap_scan_delegator_cb {
+
+	/**
+	 * @brief Attempt to add a new source to a receive state failed
+	 *
+	 * An attempt to add a new broadcast source to a receive state
+	 * failed.
+	 *
+	 * @param conn        Pointer to the connection to a remote device if
+	 *                    the change was caused by it, otherwise NULL.
+	 * @param state_info  Pointer to the receive state that was
+	 *                    attempted to be added.
+	 * @param err         errno explaining why adding the source failed
+	 *
+	 * return true if operation was successful, or false if unsuccessful
+	 *
+	 */
+	bool (*recv_state_add_failed)(struct bt_conn *conn,
+					const struct bt_bap_scan_delegator_recv_state *state_info,
+					int err);
+
 	/**
 	 * @brief Receive state updated
 	 *
@@ -1817,6 +1837,15 @@ void bt_bap_scan_delegator_foreach_state(bt_bap_scan_delegator_state_func_t func
 const struct bt_bap_scan_delegator_recv_state *bt_bap_scan_delegator_find_state(
 	bt_bap_scan_delegator_state_func_t func, void *user_data);
 
+/**
+ * @brief Find a broadcast sink by its BASS Source ID
+ *
+ * @param bass_src_id
+ *
+ * @return Pointer to the broadcast sink found
+ */
+struct bt_bap_broadcast_sink *bt_bap_broadcast_sink_get_by_bass_src_id(uint8_t bass_src_id);
+
 /******************************** CLIENT API ********************************/
 
 /**

samples/bluetooth/broadcast_audio_sink/prj.conf

@@ -10,5 +10,7 @@ CONFIG_BT_ISO_MAX_CHAN=2
 CONFIG_BT_BAP_BROADCAST_SNK_SUBGROUP_COUNT=2
 CONFIG_BT_BAP_BROADCAST_SNK_STREAM_COUNT=2
 CONFIG_BT_BAP_SCAN_DELEGATOR_MAX_SUBGROUPS=2
+CONFIG_BT_BAP_SCAN_DELEGATOR_OVERWRITE_OLDEST=y
 
 CONFIG_BT_DEVICE_NAME="Broadcast Audio Sink"
+

subsys/bluetooth/audio/Kconfig.bap

@@ -235,6 +235,14 @@ config BT_BAP_SCAN_DELEGATOR_MAX_SUBGROUPS
 	help
 	  The maximum number of BIS subgroups supported.
 
+config BT_BAP_SCAN_DELEGATOR_OVERWRITE_OLDEST
+	bool "Overwrite oldest inactive receive state"
+	help
+	  If enabled, if there are no available free receive states,
+	  the oldest inactive receive state will be overwritten. An
+	  inactive receive state is a receive state that has neither a
+	  Periodic Advertising or Broadcast Isochronous Group (BIG) sync.
+
 endif # BT_BAP_SCAN_DELEGATOR
 
 config BT_BAP_BROADCAST_ASSISTANT

subsys/bluetooth/audio/bap_broadcast_sink.c

@@ -417,7 +417,7 @@ static struct bt_bap_broadcast_sink *broadcast_sink_get_by_pa(struct bt_le_per_a
 
 static void broadcast_sink_add_src(struct bt_bap_broadcast_sink *sink)
 {
-	struct bt_bap_scan_delegator_add_src_param add_src_param;
+	struct bt_bap_scan_delegator_add_src_param add_src_param = {0};
 	int err;
 
 	add_src_param.pa_sync = sink->pa_sync;
@@ -1116,6 +1116,17 @@ int bt_bap_broadcast_sink_delete(struct bt_bap_broadcast_sink *sink)
 	return 0;
 }
 
+struct bt_bap_broadcast_sink *bt_bap_broadcast_sink_get_by_bass_src_id(uint8_t bass_src_id)
+{
+	for (size_t i = 0U; i < ARRAY_SIZE(broadcast_sinks); i++) {
+		if (broadcast_sinks[i].bass_src_id == bass_src_id) {
+		return &broadcast_sinks[i];
+		}
+	}
+
+	return NULL;
+}
+
 static int broadcast_sink_init(void)
 {
 	static struct bt_le_per_adv_sync_cb cb = {