kernel-ark/include/asm-x86_64/delay.h
Paolo 'Blaisorblade' Giarrusso e6536c1262 [PATCH] x86: comment magic constants in delay.h
For both i386 and x86_64, copy from arch/$ARCH/lib/delay.c comments about the
used magic constants, plus a few other niceties.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andi Kleen <ak@suse.de>

 include/asm-i386/delay.h   |    5 ++++-
 include/asm-x86_64/delay.h |    5 ++++-
 2 files changed, 8 insertions(+), 2 deletions(-)
2006-12-07 02:14:07 +01:00

31 lines
852 B
C

#ifndef _X8664_DELAY_H
#define _X8664_DELAY_H
/*
* Copyright (C) 1993 Linus Torvalds
*
* Delay routines calling functions in arch/x86_64/lib/delay.c
*/
/* 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 usecs);
extern void __delay(unsigned long loops);
/* 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 /* defined(_X8664_DELAY_H) */