1 files changed, 15 insertions, 1 deletions

diff --git a/include/asm-generic/delay.h b/include/asm-generic/delay.h
index 4586fec75ddb..6511b99c5f17 100644
--- a/include/asm-generic/delay.h
+++ b/include/asm-generic/delay.h
@@ -1,9 +1,23 @@
 #ifndef __ASM_GENERIC_DELAY_H
 #define __ASM_GENERIC_DELAY_H
 
+/* Undefined functions to get compile-time errors */
+extern void __bad_udelay(void);
+extern void __bad_ndelay(void);
+
 extern void __udelay(unsigned long usecs);
+extern void __ndelay(unsigned long nsecs);
+extern void __const_udelay(unsigned long xloops);
 extern void __delay(unsigned long loops);
 
-#define udelay(n) __udelay(n)
+/* 0x10c7 is 2**32 / 1000000 (rounded up) */
+#define udelay(n) (__builtin_constant_p(n) ? \
+        ((n) > 20000 ? __bad_udelay() : __const_udelay((n) * 0x10c7ul)) : \
+        __udelay(n))
+
+/* 0x5 is 2**32 / 1000000000 (rounded up) */
+#define ndelay(n) (__builtin_constant_p(n) ? \
+        ((n) > 20000 ? __bad_ndelay() : __const_udelay((n) * 5ul)) : \
+        __ndelay(n))
 
 #endif /* __ASM_GENERIC_DELAY_H */