diff options
| author | Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> | 2006-12-07 02:14:07 +0100 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2006-12-07 02:14:07 +0100 |
| commit | e6536c1262c56d302e749ab1b44fdb0b9786327d (patch) | |
| tree | 6463b5c2eb8b156a6fcfffa283a803c0f8a8949b /include/asm-i386/delay.h | |
| parent | b9a8d94a47f8a41766f6f7944adfb1d641349903 (diff) | |
[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(-)
Diffstat (limited to 'include/asm-i386/delay.h')
| -rw-r--r-- | include/asm-i386/delay.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/include/asm-i386/delay.h b/include/asm-i386/delay.h index b1c7650dc7b..9ae5e3782ed 100644 --- a/include/asm-i386/delay.h +++ b/include/asm-i386/delay.h @@ -7,6 +7,7 @@ * Delay routines calling functions in arch/i386/lib/delay.c */ +/* Undefined functions to get compile-time errors */ extern void __bad_udelay(void); extern void __bad_ndelay(void); @@ -15,10 +16,12 @@ 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)) |