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