delay.h (7a9787e1eba95a166265e6a260cf30af04ef0a99) delay.h (d0a533b18235d36206b9b422efadb7cee444dfdb)
1/*
2 * Copyright (C) 1995-2004 Russell King
3 *
4 * Delay routines, using a pre-computed "loops_per_second" value.
5 */
6#ifndef __ASM_ARM_DELAY_H
7#define __ASM_ARM_DELAY_H
8
1/*
2 * Copyright (C) 1995-2004 Russell King
3 *
4 * Delay routines, using a pre-computed "loops_per_second" value.
5 */
6#ifndef __ASM_ARM_DELAY_H
7#define __ASM_ARM_DELAY_H
8
9#include <asm/memory.h>
9#include <asm/param.h> /* HZ */
10
10#include <asm/param.h> /* HZ */
11
11extern void __delay(int loops);
12#define MAX_UDELAY_MS 2
13#define UDELAY_MULT ((UL(2199023) * HZ) >> 11)
14#define UDELAY_SHIFT 30
12
15
16#ifndef __ASSEMBLY__
17
18extern struct arm_delay_ops {
19 void (*delay)(unsigned long);
20 void (*const_udelay)(unsigned long);
21 void (*udelay)(unsigned long);
22} arm_delay_ops;
23
24#define __delay(n) arm_delay_ops.delay(n)
25
13/*
14 * This function intentionally does not exist; if you see references to
15 * it, it means that you're calling udelay() with an out of range value.
16 *
17 * With currently imposed limits, this means that we support a max delay
18 * of 2000us. Further limits: HZ<=1000 and bogomips<=3355
19 */
20extern void __bad_udelay(void);
21
22/*
23 * division by multiplication: you don't have to worry about
24 * loss of precision.
25 *
26/*
27 * This function intentionally does not exist; if you see references to
28 * it, it means that you're calling udelay() with an out of range value.
29 *
30 * With currently imposed limits, this means that we support a max delay
31 * of 2000us. Further limits: HZ<=1000 and bogomips<=3355
32 */
33extern void __bad_udelay(void);
34
35/*
36 * division by multiplication: you don't have to worry about
37 * loss of precision.
38 *
26 * Use only for very small delays ( < 1 msec). Should probably use a
39 * Use only for very small delays ( < 2 msec). Should probably use a
27 * lookup table, really, as the multiplications take much too long with
28 * short delays. This is a "reasonable" implementation, though (and the
29 * first constant multiplications gets optimized away if the delay is
30 * a constant)
31 */
40 * lookup table, really, as the multiplications take much too long with
41 * short delays. This is a "reasonable" implementation, though (and the
42 * first constant multiplications gets optimized away if the delay is
43 * a constant)
44 */
32extern void __udelay(unsigned long usecs);
33extern void __const_udelay(unsigned long);
45#define __udelay(n) arm_delay_ops.udelay(n)
46#define __const_udelay(n) arm_delay_ops.const_udelay(n)
34
47
35#define MAX_UDELAY_MS 2
36
37#define udelay(n) \
38 (__builtin_constant_p(n) ? \
39 ((n) > (MAX_UDELAY_MS * 1000) ? __bad_udelay() : \
48#define udelay(n) \
49 (__builtin_constant_p(n) ? \
50 ((n) > (MAX_UDELAY_MS * 1000) ? __bad_udelay() : \
40 __const_udelay((n) * ((2199023U*HZ)>>11))) : \
51 __const_udelay((n) * UDELAY_MULT)) : \
41 __udelay(n))
42
52 __udelay(n))
53
54/* Loop-based definitions for assembly code. */
55extern void __loop_delay(unsigned long loops);
56extern void __loop_udelay(unsigned long usecs);
57extern void __loop_const_udelay(unsigned long);
58
59#endif /* __ASSEMBLY__ */
60
43#endif /* defined(_ARM_DELAY_H) */
44
61#endif /* defined(_ARM_DELAY_H) */
62