src/system/kernel/arch/x86/arch_timer.cpp

   1 /*
   2  * Copyright 2005, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
   3  * Distributed under the terms of the MIT License.
   4  *
   5  * Copyright 2001, Travis Geiselbrecht. All rights reserved.
   6  * Distributed under the terms of the NewOS License.
   7  */
   8
   9
  10 #include <boot/stage2.h>
  11 #include <kernel.h>
  12
  13 #include <arch/int.h>
  14 #include <arch/cpu.h>
  15
  16 #include <console.h>
  17 #include <debug.h>
  18 #include <timer.h>
  19 #include <int.h>
  20 #include <safemode.h>
  21
  22 #include <arch/timer.h>
  23
  24 #include <arch/x86/smp_priv.h>
  25 #include <arch/x86/timer.h>
  26
  27
  28 //#define TRACE_TIMER
  29 #ifdef TRACE_TIMER
  30 #       define TRACE(x) dprintf x
  31 #else
  32 #       define TRACE(x) ;
  33 #endif
  34
  35 extern timer_info gPITTimer;
  36 extern timer_info gAPICTimer;
  37 extern timer_info gHPETTimer;
  38
  39 static timer_info *sTimers[] = {
  40         &gHPETTimer,
  41         &gAPICTimer,
  42         &gPITTimer,
  43         NULL
  44 };
  45
  46 static timer_info *sTimer = NULL;
  47
  48 void
  49 arch_timer_set_hardware_timer(bigtime_t timeout)
  50 {
  51         TRACE(("arch_timer_set_hardware_timer: timeout %lld\n", timeout));
  52         sTimer->set_hardware_timer(timeout);
  53 }
  54
  55
  56 void
  57 arch_timer_clear_hardware_timer(void)
  58 {
  59         TRACE(("arch_timer_clear_hardware_timer\n"));
  60         sTimer->clear_hardware_timer();
  61 }
  62
  63
  64 static void
  65 sort_timers(timer_info *timers[], int numTimers)
  66 {
  67         timer_info *tempPtr;
  68         int max = 0;
  69         int i = 0;
  70         int j = 0;
  71
  72         for (i = 0; i < numTimers - 1; i++) {
  73                 max = i;
  74                 for (j = i + 1; j < numTimers; j++) {
  75                         if (timers[j]->get_priority() > timers[max]->get_priority())
  76                                 max = j;
  77                 }
  78                 if (max != i) {
  79                         tempPtr = timers[max];
  80                         timers[max] = timers[i];
  81                         timers[i] = tempPtr;
  82                 }
  83         }
  84
  85 #if 0
  86         for (i = 0; i < numTimers; i++)
  87                 dprintf(" %s: priority %d\n", timers[i]->name, timers[i]->get_priority());
  88 #endif
  89 }
  90
  91
  92 int
  93 arch_init_timer(kernel_args *args)
  94 {
  95         // Sort timers by priority
  96         sort_timers(sTimers, (sizeof(sTimers) / sizeof(sTimers[0])) - 1);
  97
  98         timer_info *timer = NULL;
  99         cpu_status state = disable_interrupts();
 100
 101         for (int i = 0; (timer = sTimers[i]) != NULL; i++) {
 102                 if (timer->init(args) == B_OK)
 103                         break;
 104         }
 105
 106         sTimer = timer;
 107
 108         if (sTimer != NULL) {
 109                 dprintf("arch_init_timer: using %s timer.\n", sTimer->name);
 110         } else {
 111                 panic("No system timers were found usable.\n");
 112         }
 113
 114         restore_interrupts(state);
 115
 116         return 0;
 117 }
 118