kernel/timer.c

   1 #include <asm/io.h>
   2 #include <asm/system.h>
   3 #include <timer.h>
   4 #include <types.h>
   5 #include <thunix.h>
   6
   7 volatile unsigned long timer_ticks = 0;
   8 volatile unsigned long count_down = 0;
   9
  10 extern timer_interrupt(void);
  11
  12 //extern current_DOR;
  13
  14 #define TIME_REQUESTS 64
  15
  16 struct timer_list {
  17         unsigned long timer_ticks;
  18         void (*fn) ();
  19         struct timer_list *next;
  20 } timer_list[TIME_REQUESTS], * next_timer = NULL;
  21
  22
  23
  24 void add_timer( unsigned long timer_ticks, void (*fn)(void))
  25 {
  26         struct timer_list *p;
  27
  28         if (!fn)
  29                 return ;
  30         cli();
  31         if (timer_ticks <= 0)
  32                 (fn)();
  33         else {
  34                 for (p = timer_list; p < timer_list + TIME_REQUESTS ; p ++)
  35                         if (!p->fn)
  36                                 break;
  37                 if (p >= timer_list + TIME_REQUESTS)
  38                         panic("No more time requests free");
  39                 p->fn = fn;
  40                 p->timer_ticks = timer_ticks;
  41                 next_timer = p;
  42                 while (p->next && p->timer_ticks > p->next->timer_ticks) {
  43                         p->timer_ticks -= p->next->timer_ticks;
  44                         fn = p->fn;
  45                         p->fn = p->next->fn;
  46                         p->next->fn = fn;
  47
  48                         timer_ticks = p->timer_ticks;
  49                         p->timer_ticks = p->next->timer_ticks;
  50                         p->next->timer_ticks = timer_ticks;
  51                         p = p->next;
  52                 }
  53         }
  54         sti();
  55 }
  56
  57
  58 /*
  59  *   Yeah, we are implenmenting our SLEEP function,
  60  *
  61  *   Hope it works well cause i just know the folloing
  62  *  ways to implenment it by now. And you konw, it's
  63  *  very simple!
  64  *
  65  */
  66 void sleep(unsigned long sleep_value)
  67 {
  68         unsigned long now_ticks = timer_ticks;
  69         do{
  70                 ;
  71         }while ( timer_ticks < now_ticks + sleep_value);
  72
  73 }
  74
  75
  76 void do_timer(void)
  77 {
  78
  79         /*
  80          * Yeah, we also implenment a COUNT_DOWN here.
  81          * it's sounds like we have lots things well.
  82          *
  83          */
  84         if (count_down)
  85                 count_down --;
  86
  87
  88         if (next_timer) {
  89                 next_timer->timer_ticks --;
  90                 while (next_timer && next_timer->timer_ticks <=0) {
  91                         void  (*fn) (void);
  92
  93                         fn = next_timer->fn;
  94                         next_timer->fn = NULL;
  95                         next_timer = next_timer->next;
  96                         (fn)();
  97                 }
  98         }
  99
 100         //if (current_DOR & 0xf0)
 101         //      do_floppy_timer();
 102 }
 103
 104 void timer_init(int hz)
 105 {
 106   unsigned int divisor = 1193180/hz;
 107   outb(0x36, 0x43);
 108   outb(divisor&0xff, 0x40);
 109   outb(divisor>>8, 0x40);
 110   set_trap_gate(0x20,timer_interrupt);
 111   outb(inb(0x21)&0xfe, 0x21);
 112 }