File: delay.h

package info (click to toggle)
kernel-source-2.4.10 2.4.10-1
  • links: PTS
  • area: main
  • in suites: woody
  • size: 137,328 kB
  • ctags: 423,898
  • sloc: ansic: 2,403,930; asm: 140,471; makefile: 8,170; sh: 3,099; perl: 2,077; yacc: 1,177; cpp: 755; tcl: 577; lex: 343; awk: 251; lisp: 218; sed: 72
file content (37 lines) | stat: -rw-r--r-- 1,068 bytes parent folder | download | duplicates (9)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
#ifndef _LINUX_DELAY_H
#define _LINUX_DELAY_H

/*
 * Copyright (C) 1993 Linus Torvalds
 *
 * Delay routines, using a pre-computed "loops_per_jiffy" value.
 */

extern unsigned long loops_per_jiffy;

#include <asm/delay.h>

/*
 * Using udelay() for intervals greater than a few milliseconds can
 * risk overflow for high loops_per_jiffy (high bogomips) machines. The
 * mdelay() provides a wrapper to prevent this.  For delays greater
 * than MAX_UDELAY_MS milliseconds, the wrapper is used.  Architecture
 * specific values can be defined in asm-???/delay.h as an override.
 * The 2nd mdelay() definition ensures GCC will optimize away the 
 * while loop for the common cases where n <= MAX_UDELAY_MS  --  Paul G.
 */

#ifndef MAX_UDELAY_MS
#define MAX_UDELAY_MS	5
#endif

#ifdef notdef
#define mdelay(n) (\
	{unsigned long msec=(n); while (msec--) udelay(1000);})
#else
#define mdelay(n) (\
	(__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \
	({unsigned long msec=(n); while (msec--) udelay(1000);}))
#endif

#endif /* defined(_LINUX_DELAY_H) */