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