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 // no IRQ line for the LAPIC
  13 IMPLEMENT inline int Timer::irq_line() { return -1; }
  14
  15 IMPLEMENT
  16 void
  17 Timer::init()
  18 {
  19   Apic::timer_assign_irq_vector(Config::Apic_timer_vector);
  20
  21   if (Config::scheduler_one_shot)
  22     {
  23       Apic::timer_set_one_shot();
  24       Apic::timer_reg_write(0xffffffff);
  25     }
  26   else
  27     {
  28       Apic::timer_set_periodic();
  29       Apic::timer_reg_write(Apic::us_to_apic(Config::scheduler_granularity));
  30     }
  31
  32   // make sure that PIT does pull its interrupt line
  33   Pit::done();
  34
  35   if (!Config::scheduler_one_shot)
  36     // from now we can save energy in getchar()
  37     Config::getchar_does_hlt_works_ok = Config::hlt_works_ok;
  38
  39   printf ("Using the Local APIC timer on vector %x (%s Mode) for scheduling\n",
  40           Config::Apic_timer_vector,
  41           Config::scheduler_one_shot ? "One-Shot" : "Periodic");
  42 }
  43
  44 IMPLEMENT inline NEEDS["apic.h"]
  45 void
  46 Timer::acknowledge()
  47 {
  48   Apic::irq_ack();
  49 }
  50
  51 IMPLEMENT inline NEEDS["apic.h"]
  52 void
  53 Timer::enable()
  54 {
  55   Apic::timer_enable_irq();
  56   Apic::irq_ack();
  57 }
  58
  59 IMPLEMENT inline NEEDS["apic.h"]
  60 void
  61 Timer::disable()
  62 {
  63   Apic::timer_disable_irq();
  64 }
  65
  66 static
  67 void
  68 Timer::update_one_shot(Unsigned64 wakeup)
  69 {
  70   //unsigned cpu = current_cpu();
  71   Unsigned32 apic;
  72   Unsigned64 now = Kip::k()->clock; //Cpu::cpus.cpu(cpu).time_us();
  73   if (EXPECT_FALSE (wakeup <= now))
  74     // already expired
  75     apic = 1;
  76   else
  77     {
  78       Unsigned64 delta = wakeup - now;
  79       if (delta < Config::One_shot_min_interval_us)
  80         apic = Apic::us_to_apic(Config::One_shot_min_interval_us);
  81       else if (delta > Config::One_shot_max_interval_us)
  82         apic = Apic::us_to_apic(Config::One_shot_max_interval_us);
  83       else
  84         apic = Apic::us_to_apic(delta);
  85
  86       if (EXPECT_FALSE (apic < 1))
  87         // timeout too small
  88         apic = 1;
  89     }
  90
  91   Apic::timer_reg_write(apic);
  92 }
  93
  94 IMPLEMENT inline
  95 void
  96 Timer::update_timer(Unsigned64 wakeup)
  97 {
  98   if (Config::scheduler_one_shot)
  99     update_one_shot(wakeup);
 100 }