LXR linux/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
  13static irqreturn_t timer_interrupt(int irq, void *dev_id)
  14{
  15        i8253_clockevent.event_handler(&i8253_clockevent);
  16
  17        return IRQ_HANDLED;
  18}
  19
  20static struct irqaction irq0  = {
  21        .handler = timer_interrupt,
  22        .flags = IRQF_NOBALANCING | IRQF_TIMER,
  23        .name = "timer"
  24};
  25
  26void __init setup_pit_timer(void)
  27{
  28        clockevent_i8253_init(true);
  29        setup_irq(0, &irq0);
  30}
  31
  32static 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}
  39arch_initcall(init_pit_clocksource);
  40