1#ifndef _LINUX_TIMER_H
2#define _LINUX_TIMER_H
3
4#include <linux/config.h>
5#include <linux/list.h>
6
7/*
8 * In Linux 2.4, static timers have been removed from the kernel.
9 * Timers may be dynamically created and destroyed, and should be initialized
10 * by a call to init_timer() upon creation.
11 *
12 * The "data" field enables use of a common timeout function for several
13 * timeouts. You can use this field to distinguish between the different
14 * invocations.
15 */
16struct timer_list {
17	struct list_head list;
18	unsigned long expires;
19	unsigned long data;
20	void (*function)(unsigned long);
21};
22
23extern void add_timer(struct timer_list * timer);
24extern int del_timer(struct timer_list * timer);
25
26#ifdef CONFIG_SMP
27extern int del_timer_sync(struct timer_list * timer);
28extern void sync_timers(void);
29#else
30#define del_timer_sync(t)	del_timer(t)
31#define sync_timers()		do { } while (0)
32#endif
33
34/*
35 * mod_timer is a more efficient way to update the expire field of an
36 * active timer (if the timer is inactive it will be activated)
37 * mod_timer(a,b) is equivalent to del_timer(a); a->expires = b; add_timer(a).
38 * If the timer is known to be not pending (ie, in the handler), mod_timer
39 * is less efficient than a->expires = b; add_timer(a).
40 */
41int mod_timer(struct timer_list *timer, unsigned long expires);
42
43extern void it_real_fn(unsigned long);
44
45static inline void init_timer(struct timer_list * timer)
46{
47	timer->list.next = timer->list.prev = NULL;
48}
49
50static inline int timer_pending (const struct timer_list * timer)
51{
52	return timer->list.next != NULL;
53}
54
55/*
56 *	These inlines deal with timer wrapping correctly. You are
57 *	strongly encouraged to use them
58 *	1. Because people otherwise forget
59 *	2. Because if the timer wrap changes in future you wont have to
60 *	   alter your driver code.
61 *
62 * time_after(a,b) returns true if the time a is after time b.
63 *
64 * Do this with "<0" and ">=0" to only test the sign of the result. A
65 * good compiler would generate better code (and a really good compiler
66 * wouldn't care). Gcc is currently neither.
67 */
68#define time_after(a,b)		((long)(b) - (long)(a) < 0)
69#define time_before(a,b)	time_after(b,a)
70
71#define time_after_eq(a,b)	((long)(a) - (long)(b) >= 0)
72#define time_before_eq(a,b)	time_after_eq(b,a)
73
74#endif
75