1#ifndef _LINUX_DELAY_H 2#define _LINUX_DELAY_H 3 4/* 5 * Copyright (C) 1993 Linus Torvalds 6 * 7 * Delay routines, using a pre-computed "loops_per_jiffy" value. 8 */ 9 10extern unsigned long loops_per_jiffy; 11 12#include <asm/delay.h> 13 14/* 15 * Using udelay() for intervals greater than a few milliseconds can 16 * risk overflow for high loops_per_jiffy (high bogomips) machines. The 17 * mdelay() provides a wrapper to prevent this. For delays greater 18 * than MAX_UDELAY_MS milliseconds, the wrapper is used. Architecture 19 * specific values can be defined in asm-???/delay.h as an override. 20 * The 2nd mdelay() definition ensures GCC will optimize away the 21 * while loop for the common cases where n <= MAX_UDELAY_MS -- Paul G. 22 */ 23 24#ifndef MAX_UDELAY_MS 25#define MAX_UDELAY_MS 5 26#endif 27 28#ifdef notdef 29#define mdelay(n) (\ 30 {unsigned long msec=(n); while (msec--) udelay(1000);}) 31#else 32#define mdelay(n) (\ 33 (__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \ 34 ({unsigned long msec=(n); while (msec--) udelay(1000);})) 35#endif 36 37#endif /* defined(_LINUX_DELAY_H) */ 38