diff options
author | Ben Dooks <ben-linux@fluff.org> | 2008-08-08 21:10:12 +0100 |
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committer | Ben Dooks <ben-linux@fluff.org> | 2008-08-08 21:10:12 +0100 |
commit | af7a535688a758d15f06a98833e6a143b29af9de (patch) | |
tree | bac5ab210bbbbe276f0e44ed84194d7c8bb16aae /arch/arm/include/asm/delay.h | |
parent | 0c17e4ceedd35c78b1c7413dbd16279a350be6bc (diff) | |
parent | c41107c2d4fd31924533f4dbc4c3428acc2b5894 (diff) |
Merge http://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm into for-rmk
Diffstat (limited to 'arch/arm/include/asm/delay.h')
-rw-r--r-- | arch/arm/include/asm/delay.h | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/arch/arm/include/asm/delay.h b/arch/arm/include/asm/delay.h new file mode 100644 index 00000000000..b2deda18154 --- /dev/null +++ b/arch/arm/include/asm/delay.h @@ -0,0 +1,44 @@ +/* + * Copyright (C) 1995-2004 Russell King + * + * Delay routines, using a pre-computed "loops_per_second" value. + */ +#ifndef __ASM_ARM_DELAY_H +#define __ASM_ARM_DELAY_H + +#include <asm/param.h> /* HZ */ + +extern void __delay(int loops); + +/* + * This function intentionally does not exist; if you see references to + * it, it means that you're calling udelay() with an out of range value. + * + * With currently imposed limits, this means that we support a max delay + * of 2000us. Further limits: HZ<=1000 and bogomips<=3355 + */ +extern void __bad_udelay(void); + +/* + * division by multiplication: you don't have to worry about + * loss of precision. + * + * Use only for very small delays ( < 1 msec). Should probably use a + * lookup table, really, as the multiplications take much too long with + * short delays. This is a "reasonable" implementation, though (and the + * first constant multiplications gets optimized away if the delay is + * a constant) + */ +extern void __udelay(unsigned long usecs); +extern void __const_udelay(unsigned long); + +#define MAX_UDELAY_MS 2 + +#define udelay(n) \ + (__builtin_constant_p(n) ? \ + ((n) > (MAX_UDELAY_MS * 1000) ? __bad_udelay() : \ + __const_udelay((n) * ((2199023U*HZ)>>11))) : \ + __udelay(n)) + +#endif /* defined(_ARM_DELAY_H) */ + |