Bluetooth: CAP: Implement unicast to broadcast handover

Implement the unicast to broadcast handover procedure,
as per the Bluetooth CAP specificiation.

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

Author: Thalley

doc/zephyr.doxyfile.in

@@ -286,6 +286,8 @@ ALIASES                = "kconfig{1}=\c \1" \
                          "kconfig_dep{1}=\attention Available only when the following Kconfig option is enabled: \kconfig{\1}." \
                          "kconfig_dep{2}=\attention Available only when the following Kconfig options are enabled: \kconfig{\1}, \kconfig{\2}." \
                          "kconfig_dep{3}=\attention Available only when the following Kconfig options are enabled: \kconfig{\1}, \kconfig{\2}, \kconfig{\3}." \
+                         "kconfig_dep{4}=\attention Available only when the following Kconfig options are enabled: \kconfig{\1}, \kconfig{\2}, \kconfig{\3}, \kconfig{\4}." \
+                         "kconfig_dep{5}=\attention Available only when the following Kconfig options are enabled: \kconfig{\1}, \kconfig{\2}, \kconfig{\3}, \kconfig{\4}, \kconfig{\5}." \
                          "funcprops=\par \"Function properties (list may not be complete)\"" \
                          "reschedule=\qualifier reschedule" \
                          "sleep=\qualifier sleep" \

include/zephyr/bluetooth/audio/bap.h

@@ -1672,6 +1672,32 @@ int bt_bap_unicast_group_add_streams(struct bt_bap_unicast_group *unicast_group,
  */
 int bt_bap_unicast_group_delete(struct bt_bap_unicast_group *unicast_group);
 
+/** Callback function for bt_bap_unicast_group_foreach_stream()
+ *
+ * @param stream     The audio stream
+ * @param user_data  User data
+ *
+ * @retval true Stop iterating.
+ * @retval false Continue iterating.
+ */
+typedef bool (*bt_bap_unicast_group_foreach_stream_func_t)(struct bt_bap_stream *stream,
+							   void *user_data);
+
+/**
+ * @brief Iterate through all streams in a unicast group
+ *
+ * @param unicast_group  The unicast group
+ * @param func           The callback function
+ * @param user_data      User specified data that sent to the callback function
+ *
+ * @retval 0 Success (even if no streams exists in the group).
+ * @retval -ECANCELED Iteration was stopped by the callback function before complete.
+ * @retval -EINVAL @p unicast_group or @p func were NULL.
+ */
+int bt_bap_unicast_group_foreach_stream(struct bt_bap_unicast_group *unicast_group,
+					bt_bap_unicast_group_foreach_stream_func_t func,
+					void *user_data);
+
 /** Unicast Client callback structure */
 struct bt_bap_unicast_client_cb {
 	/**

include/zephyr/bluetooth/audio/cap.h

@@ -639,21 +639,24 @@ int bt_cap_initiator_broadcast_get_base(struct bt_cap_broadcast_source *broadcas
 
 /** Parameters for  bt_cap_initiator_unicast_to_broadcast() */
 struct bt_cap_unicast_to_broadcast_param {
+	/** The type of the set. */
+	enum bt_cap_set_type type;
+
 	/** The source unicast group with the streams. */
 	struct bt_bap_unicast_group *unicast_group;
 
 	/**
 	 * @brief Whether or not to encrypt the streams.
 	 *
-	 * If set to true, then the broadcast code in @p broadcast_code
-	 * will be used to encrypt the streams.
+	 * If set to true, then the broadcast code in
+	 * @p bt_cap_unicast_to_broadcast_param.broadcast_code will be used to encrypt the streams.
 	 */
 	bool encrypt;
 
 	/**
 	 * @brief 16-octet broadcast code.
 	 *
-	 * Only valid if @p encrypt is true.
+	 * Only valid if @p bt_cap_unicast_to_broadcast_param.encrypt is true.
 	 *
 	 * If the value is a string or a the value is less than 16 octets,
 	 * the remaining octets shall be 0.
@@ -671,10 +674,13 @@ struct bt_cap_unicast_to_broadcast_param {
  * The streams in the unicast group will be stopped and the unicast group
  * will be deleted. This can only be done for source streams.
  *
- * @note @kconfig{CONFIG_BT_CAP_INITIATOR},
- * @kconfig{CONFIG_BT_BAP_UNICAST_CLIENT} and
- * @kconfig{CONFIG_BT_BAP_BROADCAST_SOURCE} must be enabled for this function
- * to be enabled.
+ * @kconfig_dep{
+ *   CONFIG_BT_CAP_INITIATOR,
+ *   CONFIG_BT_CAP_COMMANDER,
+ *   CONFIG_BT_BAP_BROADCAST_ASSISTANT,
+ *   CONFIG_BT_BAP_BROADCAST_SOURCE,
+ *   CONFIG_BT_BAP_UNICAST_CLIENT
+ * }
  *
  * @param param         The parameters for the handover.
  * @param source        The resulting broadcast source.
@@ -715,10 +721,7 @@ struct bt_cap_broadcast_to_unicast_param {
  * The streams in the broadcast source will be stopped and the broadcast source
  * will be deleted.
  *
- * @note @kconfig{CONFIG_BT_CAP_INITIATOR},
- * @kconfig{CONFIG_BT_BAP_UNICAST_CLIENT} and
- * @kconfig{CONFIG_BT_BAP_BROADCAST_SOURCE} must be enabled for this function
- * to be enabled.
+ * @kconfig_dep{CONFIG_BT_CAP_INITIATOR,CONFIG_BT_BAP_UNICAST_CLIENT,CONFIG_BT_BAP_BROADCAST_SOURCE}
  *
  * @param[in]  param          The parameters for the handover.
  * @param[out] unicast_group  The resulting broadcast source.

subsys/bluetooth/audio/bap_unicast_client.c

@@ -3141,6 +3141,33 @@ int bt_bap_unicast_group_delete(struct bt_bap_unicast_group *unicast_group)
 	return 0;
 }
 
+int bt_bap_unicast_group_foreach_stream(struct bt_bap_unicast_group *unicast_group,
+					bt_bap_unicast_group_foreach_stream_func_t func,
+					void *user_data)
+{
+	struct bt_bap_stream *stream, *next;
+
+	if (unicast_group == NULL) {
+		LOG_DBG("unicast_group is NULL");
+		return -EINVAL;
+	}
+
+	if (func == NULL) {
+		LOG_DBG("func is NULL");
+		return -EINVAL;
+	}
+
+	SYS_SLIST_FOR_EACH_CONTAINER_SAFE(&unicast_group->streams, stream, next, _node) {
+		const bool stop = func(stream, user_data);
+
+		if (stop) {
+			return -ECANCELED;
+		}
+	}
+
+	return 0;
+}
+
 int bt_bap_unicast_client_config(struct bt_bap_stream *stream,
 				 const struct bt_audio_codec_cfg *codec_cfg)
 {

subsys/bluetooth/audio/cap_initiator.c

@@ -2244,13 +2244,82 @@ void bt_cap_initiator_released(struct bt_cap_stream *cap_stream)
 
 #endif /* CONFIG_BT_BAP_UNICAST_CLIENT */
 
-#if defined(CONFIG_BT_BAP_BROADCAST_SOURCE) && defined(CONFIG_BT_BAP_UNICAST_CLIENT)
+#if defined(CONFIG_BT_CAP_COMMANDER) && defined(CONFIG_BT_BAP_BROADCAST_SOURCE) &&                 \
+	defined(CONFIG_BT_BAP_UNICAST_CLIENT) && defined(CONFIG_BT_BAP_BROADCAST_ASSISTANT)
+
+static bool valid_unicast_to_broadcast_param(const struct bt_cap_unicast_to_broadcast_param *param)
+{
+	const struct bt_bap_unicast_group *unicast_group;
+
+	if (param == NULL) {
+		LOG_DBG("param is NULL");
+		return false;
+	}
+
+	unicast_group = param->unicast_group;
+	if (unicast_group == NULL) {
+		LOG_DBG("param->unicast_group is NULL");
+		return false;
+	}
+
+	if (unicast_group->cig == NULL) {
+		LOG_DBG("param->unicast_group is not configured");
+		return false;
+	}
+
+	/**
+	 * 1) Get all sink streams in the streaming state from unicast group
+	 * 2) If number of sink streams exceed the number of broadcast source streams supported
+return error
+	 * 3) If number of unique metadata configurations exceed number of subgroups supported
+return error
+	 * 4) Check if remote device supports broadcast before doing anything
+	 * 5) Release all sink streams with bt_cap_initiator_unicast_audio_stop
+	 * 6) Once completed, call bt_cap_initiator_broadcast_audio_start
+	 * 7) Call handover callback once completed
+	 */
+
+	return true;
+}
 
 int bt_cap_initiator_unicast_to_broadcast(
 	const struct bt_cap_unicast_to_broadcast_param *param,
 	struct bt_cap_broadcast_source **source)
 {
-	return -ENOSYS;
+	struct bt_cap_unicast_audio_stop_param stop_param = {0};
+	int err;
+
+	if (source == NULL) {
+		LOG_DBG("source is NULL");
+		return -EINVAL;
+	}
+
+	if (!valid_unicast_to_broadcast_param(param)) {
+		return -EINVAL;
+	}
+
+	if (bt_cap_common_test_and_set_proc_active()) {
+		LOG_DBG("A CAP procedure is already in progress");
+
+		return -EBUSY;
+	}
+
+	stop_param.type = param->type;
+	stop_param.release = true;
+	/* TODO: Populate array of streams
+	 * Since input is a BAP group, how do we ensure they are CAP streams?
+	 */
+
+	err = bt_cap_initiator_unicast_audio_stop(&stop_param);
+	if (err != 0) {
+		LOG_DBG("Failed to stop unicast audio: %d", err);
+
+		bt_cap_common_clear_active_proc();
+
+		return -ENOEXEC;
+	}
+
+	return 0;
 }
 
 int bt_cap_initiator_broadcast_to_unicast(const struct bt_cap_broadcast_to_unicast_param *param,
@@ -2259,4 +2328,6 @@ int bt_cap_initiator_broadcast_to_unicast(const struct bt_cap_broadcast_to_unica
 	return -ENOSYS;
 }
 
-#endif /* CONFIG_BT_BAP_BROADCAST_SOURCE && CONFIG_BT_BAP_UNICAST_CLIENT */
+#endif /* CONFIG_BT_CAP_COMMANDER && CONFIG_BT_BAP_BROADCAST_SOURCE &&                             \
+	* CONFIG_BT_BAP_UNICAST_CLIENT && CONFIG_BT_BAP_BROADCAST_ASSISTANT                        \
+	*/