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-rw-r--r--include/asm-generic/delay.h16
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 */