diff --git a/include/clock.h b/include/clock.h
index 691befc..681e3ad 100644
--- a/include/clock.h
+++ b/include/clock.h
@@ -34,9 +34,8 @@
 int is_timeout(uint64_t start_ns, uint64_t time_offset_ns);
 int is_timeout_non_interruptible(uint64_t start_ns, uint64_t time_offset_ns);
 
-// void udelay(unsigned long usecs);
-
 void ndelay(unsigned long nsecs);
+void udelay(unsigned long usecs);
 void mdelay(unsigned long msecs);
 
 #define SECOND ((uint64_t)(1000 * 1000 * 1000))
diff --git a/include/common.h b/include/common.h
index 553a7f4..03ceec2 100644
--- a/include/common.h
+++ b/include/common.h
@@ -23,6 +23,7 @@
 #include <stdio.h>
 #include <module.h>
 #include <config.h>
+#include <clock.h>
 #include <linux/bitops.h>
 #include <linux/types.h>
 #include <linux/string.h>
@@ -69,10 +70,6 @@
 /* $(CPU)/cpu.c */
 void __noreturn poweroff(void);
 
-/* lib_$(ARCH)/time.c */
-void	udelay (unsigned long);
-void	mdelay (unsigned long);
-
 /* lib_generic/crc32.c */
 uint32_t crc32(uint32_t, const void*, unsigned int);
 uint32_t crc32_no_comp(uint32_t, const void*, unsigned int);