LXR linux/arch/mips/kernel/i8253.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * i8253.c  8253/PIT functions
   4 *
   5 */
   6#include <linux/clockchips.h>
   7#include <linux/i8253.h>
   8#include <linux/export.h>
   9#include <linux/smp.h>
  10#include <linux/irq.h>
  11
  12#include <asm/time.h>
  13
  14static irqreturn_t timer_interrupt(int irq, void *dev_id)
  15{
  16        i8253_clockevent.event_handler(&i8253_clockevent);
  17
  18        return IRQ_HANDLED;
  19}
  20
  21static struct irqaction irq0  = {
  22        .handler = timer_interrupt,
  23        .flags = IRQF_NOBALANCING | IRQF_TIMER,
  24        .name = "timer"
  25};
  26
  27void __init setup_pit_timer(void)
  28{
  29        clockevent_i8253_init(true);
  30        setup_irq(0, &irq0);
  31}
  32
  33static int __init init_pit_clocksource(void)
  34{
  35        if (num_possible_cpus() > 1) /* PIT does not scale! */
  36                return 0;
  37
  38        return clocksource_i8253_init();
  39}
  40arch_initcall(init_pit_clocksource);
  41