kernel/fiasco/src/kern/ia32/timer-apic.cpp

   1 IMPLEMENTATION [apic_timer]:
   2
   3 #include <cstdio>
   4
   5 #include "apic.h"
   6 #include "config.h"
   7 #include "cpu.h"
   8 #include "logdefs.h"
   9 #include "pit.h"
  10 #include "std_macros.h"
  11
  12 IMPLEMENT
  13 void
  14 Timer::init()
  15 {
  16   Apic::timer_assign_irq_vector(Config::scheduler_irq_vector);
  17
  18   if (Config::scheduler_one_shot)
  19     {
  20       Apic::timer_set_one_shot();
  21       Apic::timer_reg_write(0xffffffff);
  22     }
  23   else
  24     {
  25       Apic::timer_set_periodic();
  26       Apic::timer_reg_write(Apic::us_to_apic(Config::scheduler_granularity));
  27     }
  28
  29   // make sure that PIT does pull its interrupt line
  30   Pit::done();
  31
  32   if (!Config::scheduler_one_shot)
  33     // from now we can save energy in getchar()
  34     Config::getchar_does_hlt_works_ok = Config::hlt_works_ok;
  35
  36   printf ("Using the Local APIC timer on vector %x (%s Mode) for scheduling\n",
  37           Config::scheduler_irq_vector,
  38           Config::scheduler_one_shot ? "One-Shot" : "Periodic");
  39 }
  40
  41 IMPLEMENT inline NEEDS["apic.h"]
  42 void
  43 Timer::acknowledge()
  44 {
  45   Apic::irq_ack();
  46 }
  47
  48 IMPLEMENT inline NEEDS["apic.h"]
  49 void
  50 Timer::enable()
  51 {
  52   Apic::timer_enable_irq();
  53   Apic::irq_ack();
  54 }
  55
  56 IMPLEMENT inline NEEDS["apic.h"]
  57 void
  58 Timer::disable()
  59 {
  60   Apic::timer_disable_irq();
  61 }
  62
  63 static
  64 void
  65 Timer::update_one_shot(Unsigned64 wakeup)
  66 {
  67   //unsigned cpu = current_cpu();
  68   Unsigned32 apic;
  69   Unsigned64 now = Kip::k()->clock; //Cpu::cpus.cpu(cpu).time_us();
  70   if (EXPECT_FALSE (wakeup <= now))
  71     // already expired
  72     apic = 1;
  73   else
  74     {
  75       Unsigned64 delta = wakeup - now;
  76       if (delta < Config::One_shot_min_interval_us)
  77         apic = Apic::us_to_apic(Config::One_shot_min_interval_us);
  78       else if (delta > Config::One_shot_max_interval_us)
  79         apic = Apic::us_to_apic(Config::One_shot_max_interval_us);
  80       else
  81         apic = Apic::us_to_apic(delta);
  82
  83       if (EXPECT_FALSE (apic < 1))
  84         // timeout too small
  85         apic = 1;
  86     }
  87
  88   Apic::timer_reg_write(apic);
  89 }
  90
  91 IMPLEMENT inline
  92 void
  93 Timer::update_timer(Unsigned64 wakeup)
  94 {
  95   if (Config::scheduler_one_shot)
  96     update_one_shot(wakeup);
  97 }