diff --git a/c/src/lib/libbsp/lm32/shared/milkymist_timer/timer.c b/c/src/lib/libbsp/lm32/shared/milkymist_timer/timer.c
index bba2eee164..74d59956ec 100644
--- a/c/src/lib/libbsp/lm32/shared/milkymist_timer/timer.c
+++ b/c/src/lib/libbsp/lm32/shared/milkymist_timer/timer.c
@@ -20,6 +20,7 @@
 #include <rtems.h>
 #include <bsp.h>
 #include <rtems/btimer.h>
+#include <rtems/bspIo.h>
 #include "../include/system_conf.h"
 #include "../../shared/clock/clock.h"