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-rw-r--r--include/asm-generic/delay.h37
1 files changed, 36 insertions, 1 deletions
diff --git a/include/asm-generic/delay.h b/include/asm-generic/delay.h
index 4586fec75dd..0f79054ce7c 100644
--- a/include/asm-generic/delay.h
+++ b/include/asm-generic/delay.h
@@ -1,9 +1,44 @@
#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)
+/*
+ * The weird n/20000 thing suppresses a "comparison is always false due to
+ * limited range of data type" warning with non-const 8-bit arguments.
+ */
+
+/* 0x10c7 is 2**32 / 1000000 (rounded up) */
+#define udelay(n) \
+ ({ \
+ if (__builtin_constant_p(n)) { \
+ if ((n) / 20000 >= 1) \
+ __bad_udelay(); \
+ else \
+ __const_udelay((n) * 0x10c7ul); \
+ } else { \
+ __udelay(n); \
+ } \
+ })
+
+/* 0x5 is 2**32 / 1000000000 (rounded up) */
+#define ndelay(n) \
+ ({ \
+ if (__builtin_constant_p(n)) { \
+ if ((n) / 20000 >= 1) \
+ __bad_ndelay(); \
+ else \
+ __const_udelay((n) * 5ul); \
+ } else { \
+ __ndelay(n); \
+ } \
+ })
#endif /* __ASM_GENERIC_DELAY_H */