42 lines
824 B
C
42 lines
824 B
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* i8253.c 8253/PIT functions
|
|
*
|
|
*/
|
|
#include <linux/clockchips.h>
|
|
#include <linux/i8253.h>
|
|
#include <linux/export.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/irq.h>
|
|
|
|
#include <asm/time.h>
|
|
|
|
static irqreturn_t timer_interrupt(int irq, void *dev_id)
|
|
{
|
|
i8253_clockevent.event_handler(&i8253_clockevent);
|
|
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
static struct irqaction irq0 = {
|
|
.handler = timer_interrupt,
|
|
.flags = IRQF_NOBALANCING | IRQF_TIMER,
|
|
.name = "timer"
|
|
};
|
|
|
|
void __init setup_pit_timer(void)
|
|
{
|
|
clockevent_i8253_init(true);
|
|
setup_irq(0, &irq0);
|
|
}
|
|
|
|
static int __init init_pit_clocksource(void)
|
|
{
|
|
if (num_possible_cpus() > 1 || /* PIT does not scale! */
|
|
!clockevent_state_periodic(&i8253_clockevent))
|
|
return 0;
|
|
|
|
return clocksource_i8253_init();
|
|
}
|
|
arch_initcall(init_pit_clocksource);
|