Bluetooth: BAP: BA: Replace bools with atomic

Replace the boolean values for the BAP Broadcast Assistant
with an atomic value. This prevents a rare, but possible,
race condition.

The busy flag has been replaced with 3 atomic values which
provide better granularity in error handling, and allows for
some concurrent write and read requests.

To describe the new behavior, the return values in the documentation
has been updated, and the error handling in the API
functions has improved.

Signed-off-by: Emil Gydesen <[email protected]>

Author: Thalley

include/zephyr/bluetooth/audio/bap.h

@@ -2321,7 +2321,13 @@ struct bt_bap_broadcast_assistant_cb {
  * new connection, will delete all previous data.
  *
  * @param conn  The connection
- * @return int  Error value. 0 on success, GATT error or ERRNO on fail.
+ *
+ * @retval 0 Success
+ * @retval -EINVAL @p conn is NULL
+ * @retval -EBUSY Another operation is already in progress for this @p conn
+ * @retval -ENOTCONN @p conn is not connected
+ * @retval -ENOMEM Could not allocated memory for the request
+ * @retval -ENOEXEC Unexpected GATT error
  */
 int bt_bap_broadcast_assistant_discover(struct bt_conn *conn);
 
@@ -2340,7 +2346,14 @@ int bt_bap_broadcast_assistant_discover(struct bt_conn *conn);
  *                      Used to let the server know that we are scanning.
  * @param start_scan    Start scanning if true. If false, the application should
  *                      enable scan itself.
- * @return int          Error value. 0 on success, GATT error or ERRNO on fail.
+
+ * @retval 0 Success
+ * @retval -EINVAL @p conn is NULL of if @p conn has not done discovery
+ * @retval -EBUSY Another operation is already in progress for this @p conn
+ * @retval -EAGAIN Bluetooth has not been enabled.
+ * @retval -ENOTCONN @p conn is not connected
+ * @retval -ENOMEM Could not allocated memory for the request
+ * @retval -ENOEXEC Unexpected scan or GATT error
  */
 int bt_bap_broadcast_assistant_scan_start(struct bt_conn *conn,
 					  bool start_scan);
@@ -2349,7 +2362,14 @@ int bt_bap_broadcast_assistant_scan_start(struct bt_conn *conn,
  * @brief Stop remote scanning for BISes for a server.
  *
  * @param conn   Connection to the server.
- * @return int   Error value. 0 on success, GATT error or ERRNO on fail.
+
+ * @retval 0 Success
+ * @retval -EINVAL @p conn is NULL of if @p conn has not done discovery
+ * @retval -EBUSY Another operation is already in progress for this @p conn
+ * @retval -EAGAIN Bluetooth has not been enabled.
+ * @retval -ENOTCONN @p conn is not connected
+ * @retval -ENOMEM Could not allocated memory for the request
+ * @retval -ENOEXEC Unexpected scan or GATT error
  */
 int bt_bap_broadcast_assistant_scan_stop(struct bt_conn *conn);
 
@@ -2410,7 +2430,12 @@ struct bt_bap_broadcast_assistant_add_src_param {
  * @param conn          Connection to the server.
  * @param param         Parameter struct.
  *
- * @return Error value. 0 on success, GATT error or ERRNO on fail.
+ * @retval 0 Success
+ * @retval -EINVAL @p conn is NULL or %p conn has not done discovery or if @p param is invalid
+ * @retval -EBUSY Another operation is already in progress for this @p conn
+ * @retval -ENOTCONN @p conn is not connected
+ * @retval -ENOMEM Could not allocated memory for the request
+ * @retval -ENOEXEC Unexpected scan or GATT error
  */
 int bt_bap_broadcast_assistant_add_src(
 	struct bt_conn *conn, const struct bt_bap_broadcast_assistant_add_src_param *param);
@@ -2443,7 +2468,12 @@ struct bt_bap_broadcast_assistant_mod_src_param {
  * @param conn          Connection to the server.
  * @param param         Parameter struct.
  *
- * @return Error value. 0 on success, GATT error or ERRNO on fail.
+ * @retval 0 Success
+ * @retval -EINVAL @p conn is NULL or %p conn has not done discovery or if @p param is invalid
+ * @retval -EBUSY Another operation is already in progress for this @p conn
+ * @retval -ENOTCONN @p conn is not connected
+ * @retval -ENOMEM Could not allocated memory for the request
+ * @retval -ENOEXEC Unexpected scan or GATT error
  */
 int bt_bap_broadcast_assistant_mod_src(
 	struct bt_conn *conn, const struct bt_bap_broadcast_assistant_mod_src_param *param);
@@ -2455,7 +2485,12 @@ int bt_bap_broadcast_assistant_mod_src(
  * @param src_id          Source ID of the receive state.
  * @param broadcast_code  The broadcast code.
  *
- * @return Error value. 0 on success, GATT error or ERRNO on fail.
+ * @retval 0 Success
+ * @retval -EINVAL @p conn is NULL or %p conn has not done discovery or @p src_id is invalid
+ * @retval -EBUSY Another operation is already in progress for this @p conn
+ * @retval -ENOTCONN @p conn is not connected
+ * @retval -ENOMEM Could not allocated memory for the request
+ * @retval -ENOEXEC Unexpected scan or GATT error
  */
 int bt_bap_broadcast_assistant_set_broadcast_code(
 	struct bt_conn *conn, uint8_t src_id,
@@ -2467,7 +2502,12 @@ int bt_bap_broadcast_assistant_set_broadcast_code(
  * @param conn            Connection to the server.
  * @param src_id          Source ID of the receive state.
  *
- * @return Error value. 0 on success, GATT error or ERRNO on fail.
+ * @retval 0 Success
+ * @retval -EINVAL @p conn is NULL or %p conn has not done discovery or @p src_id is invalid
+ * @retval -EBUSY Another operation is already in progress for this @p conn
+ * @retval -ENOTCONN @p conn is not connected
+ * @retval -ENOMEM Could not allocated memory for the request
+ * @retval -ENOEXEC Unexpected scan or GATT error
  */
 int bt_bap_broadcast_assistant_rem_src(struct bt_conn *conn, uint8_t src_id);
 
@@ -2478,7 +2518,12 @@ int bt_bap_broadcast_assistant_rem_src(struct bt_conn *conn, uint8_t src_id);
  * @param idx      The index of the receive start (0 up to the value from
  *                 bt_bap_broadcast_assistant_discover_cb)
  *
- * @return Error value. 0 on success, GATT error or ERRNO on fail.
+ * @retval 0 Success
+ * @retval -EINVAL @p conn is NULL or %p conn has not done discovery or @p src_id is invalid
+ * @retval -EBUSY Another operation is already in progress for this @p conn
+ * @retval -ENOTCONN @p conn is not connected
+ * @retval -ENOMEM Could not allocated memory for the request
+ * @retval -ENOEXEC Unexpected scan or GATT error
  */
 int bt_bap_broadcast_assistant_read_recv_state(struct bt_conn *conn, uint8_t idx);