board_common:Added new API point board_on_reset

  This optionally provided function called on entry to
  board_system_reset. It should perform any house keeping
  prior to retunring to do the rest.

src/drivers/boards/common/board_common.h

@@ -310,6 +310,24 @@ __EXPORT void board_rc_input(bool invert_on);
 #  endif
 #endif
 
+/************************************************************************************
+ * Name: board_on_reset
+ *
+ * Description:
+ * Optionally provided function called on entry to board_system_reset
+ * It should perform any house keeping prior to the rest.
+ *
+ * status - 1 if resetting to boot loader
+ *          0 if just resetting
+ *
+ ************************************************************************************/
+
+#if defined(BOARD_HAS_NO_RESET) || !defined(BOARD_HAS_ON_RESET)
+#  define board_on_reset(status)
+#else
+__EXPORT void board_on_reset(int status);
+#endif
+
 /************************************************************************************
  * Name: board_reset
  *

src/drivers/boards/common/stm32/board_reset.c

@@ -69,6 +69,9 @@ int board_set_bootload_mode(board_reset_e mode)
 
 void board_system_reset(int status)
 {
+#if defined(BOARD_HAS_ON_RESET)
+	board_on_reset(status);
+#endif
 	board_reset(status);
 
 	while (1);