arch/mips/kernel/i8253.c

   1 /*
   2  * i8253.c  8253/PIT functions
   3  *
   4  */
   5 #include <linux/clockchips.h>
   6 #include <linux/i8253.h>
   7 #include <linux/export.h>
   8 #include <linux/smp.h>
   9 #include <linux/irq.h>
  10
  11 #include <asm/time.h>
  12
  13 static irqreturn_t timer_interrupt(int irq, void *dev_id)
  14 {
  15         i8253_clockevent.event_handler(&i8253_clockevent);
  16
  17         return IRQ_HANDLED;
  18 }
  19
  20 static struct irqaction irq0  = {
  21         .handler = timer_interrupt,
  22         .flags = IRQF_NOBALANCING | IRQF_TIMER,
  23         .name = "timer"
  24 };
  25
  26 void __init setup_pit_timer(void)
  27 {
  28         clockevent_i8253_init(true);
  29         setup_irq(0, &irq0);
  30 }
  31
  32 static int __init init_pit_clocksource(void)
  33 {
  34         if (num_possible_cpus() > 1) /* PIT does not scale! */
  35                 return 0;
  36
  37         return clocksource_i8253_init();
  38 }
  39 arch_initcall(init_pit_clocksource);