include/linux/timer.h

   1 #ifndef _LINUX_TIMER_H
   2 #define _LINUX_TIMER_H
   3
   4 /*
   5  * Old-style timers. Please don't use for any new code.
   6  *
   7  * Numbering of these timers should be consecutive to minimize
   8  * processing delays. [MJ]
   9  */
  10
  11 #define BLANK_TIMER     0       /* Console screen-saver */
  12 #define BEEP_TIMER      1       /* Console beep */
  13 #define RS_TIMER        2       /* RS-232 ports */
  14 #define SWAP_TIMER      3       /* Background pageout */
  15 #define BACKGR_TIMER    4       /* io_request background I/O */
  16 #define HD_TIMER        5       /* Old IDE driver */
  17 #define FLOPPY_TIMER    6       /* Floppy */
  18 #define QIC02_TAPE_TIMER 7      /* QIC 02 tape */
  19 #define MCD_TIMER       8       /* Mitsumi CDROM */
  20 #define GSCD_TIMER      9       /* Goldstar CDROM */
  21 #define COMTROL_TIMER   10      /* Comtrol serial */
  22 #define DIGI_TIMER      11      /* Digi serial */
  23 #define GDTH_TIMER      12      /* Ugh - gdth scsi driver */
  24
  25 #define COPRO_TIMER     31      /* 387 timeout for buggy hardware (boot only) */
  26
  27 struct timer_struct {
  28         unsigned long expires;
  29         void (*fn)(void);
  30 };
  31
  32 extern unsigned long timer_active;
  33 extern struct timer_struct timer_table[32];
  34
  35 /*
  36  * This is completely separate from the above, and is the
  37  * "new and improved" way of handling timers more dynamically.
  38  * Hopefully efficient and general enough for most things.
  39  *
  40  * The "hardcoded" timers above are still useful for well-
  41  * defined problems, but the timer-list is probably better
  42  * when you need multiple outstanding timers or similar.
  43  *
  44  * The "data" field is in case you want to use the same
  45  * timeout function for several timeouts. You can use this
  46  * to distinguish between the different invocations.
  47  */
  48 struct timer_list {
  49         struct timer_list *next; /* MUST be first element */
  50         struct timer_list *prev;
  51         unsigned long expires;
  52         unsigned long data;
  53         void (*function)(unsigned long);
  54 };
  55
  56 extern void add_timer(struct timer_list * timer);
  57 extern int  del_timer(struct timer_list * timer);
  58
  59 /*
  60  * mod_timer is a more efficient way to update the expire field of an
  61  * active timer (if the timer is inactive it will be activated)
  62  * mod_timer(a,b) is equivalent to del_timer(a); a->expires = b; add_timer(a)
  63  */
  64 void mod_timer(struct timer_list *timer, unsigned long expires);
  65
  66 extern void it_real_fn(unsigned long);
  67
  68 extern inline void init_timer(struct timer_list * timer)
  69 {
  70         timer->next = NULL;
  71         timer->prev = NULL;
  72 }
  73
  74 extern inline int timer_pending(const struct timer_list * timer)
  75 {
  76         return timer->prev != NULL;
  77 }
  78
  79 /*
  80  *      These inlines deal with timer wrapping correctly. You are
  81  *      strongly encouraged to use them
  82  *      1. Because people otherwise forget
  83  *      2. Because if the timer wrap changes in future you wont have to
  84  *         alter your driver code.
  85  *
  86  * Do this with "<0" and ">=0" to only test the sign of the result. A
  87  * good compiler would generate better code (and a really good compiler
  88  * wouldn't care). Gcc is currently neither.
  89  */
  90 #define time_after(a,b)         ((long)(b) - (long)(a) < 0)
  91 #define time_before(a,b)        time_after(b,a)
  92
  93 #define time_after_eq(a,b)      ((long)(a) - (long)(b) >= 0)
  94 #define time_before_eq(a,b)     time_after_eq(b,a)
  95
  96 #endif