mirror of https://gitee.com/openkylin/linux.git
[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(-)
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@ -7,6 +7,7 @@
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* Delay routines calling functions in arch/i386/lib/delay.c
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*/
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/* Undefined functions to get compile-time errors */
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extern void __bad_udelay(void);
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extern void __bad_ndelay(void);
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@ -15,10 +16,12 @@ extern void __ndelay(unsigned long nsecs);
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extern void __const_udelay(unsigned long usecs);
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extern void __delay(unsigned long loops);
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/* 0x10c7 is 2**32 / 1000000 (rounded up) */
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#define udelay(n) (__builtin_constant_p(n) ? \
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((n) > 20000 ? __bad_udelay() : __const_udelay((n) * 0x10c7ul)) : \
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__udelay(n))
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/* 0x5 is 2**32 / 1000000000 (rounded up) */
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#define ndelay(n) (__builtin_constant_p(n) ? \
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((n) > 20000 ? __bad_ndelay() : __const_udelay((n) * 5ul)) : \
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__ndelay(n))
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@ -7,18 +7,21 @@
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* Delay routines calling functions in arch/x86_64/lib/delay.c
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*/
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/* Undefined functions to get compile-time errors */
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extern void __bad_udelay(void);
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extern void __bad_ndelay(void);
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extern void __udelay(unsigned long usecs);
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extern void __ndelay(unsigned long usecs);
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extern void __ndelay(unsigned long nsecs);
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extern void __const_udelay(unsigned long usecs);
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extern void __delay(unsigned long loops);
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/* 0x10c7 is 2**32 / 1000000 (rounded up) */
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#define udelay(n) (__builtin_constant_p(n) ? \
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((n) > 20000 ? __bad_udelay() : __const_udelay((n) * 0x10c7ul)) : \
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__udelay(n))
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/* 0x5 is 2**32 / 1000000000 (rounded up) */
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#define ndelay(n) (__builtin_constant_p(n) ? \
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((n) > 20000 ? __bad_ndelay() : __const_udelay((n) * 5ul)) : \
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__ndelay(n))
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