2007-10-11 16:46:10 -06:00
|
|
|
/*
|
|
|
|
* i8253.c 8253/PIT functions
|
|
|
|
*
|
|
|
|
*/
|
|
|
|
#include <linux/clockchips.h>
|
2011-06-01 12:04:57 -06:00
|
|
|
#include <linux/i8253.h>
|
2011-07-23 14:30:40 -06:00
|
|
|
#include <linux/export.h>
|
2009-06-19 07:05:26 -06:00
|
|
|
#include <linux/smp.h>
|
2010-10-07 07:08:54 -06:00
|
|
|
#include <linux/irq.h>
|
2007-10-11 16:46:10 -06:00
|
|
|
|
2007-11-01 08:38:20 -06:00
|
|
|
#include <asm/time.h>
|
2007-10-11 16:46:10 -06:00
|
|
|
|
2007-11-01 08:38:20 -06:00
|
|
|
static irqreturn_t timer_interrupt(int irq, void *dev_id)
|
2007-10-11 16:46:10 -06:00
|
|
|
{
|
2011-07-22 03:17:11 -06:00
|
|
|
i8253_clockevent.event_handler(&i8253_clockevent);
|
2007-10-11 16:46:10 -06:00
|
|
|
|
|
|
|
return IRQ_HANDLED;
|
|
|
|
}
|
|
|
|
|
|
|
|
static struct irqaction irq0 = {
|
|
|
|
.handler = timer_interrupt,
|
2011-11-22 07:38:03 -07:00
|
|
|
.flags = IRQF_NOBALANCING | IRQF_TIMER,
|
2007-10-11 16:46:10 -06:00
|
|
|
.name = "timer"
|
|
|
|
};
|
|
|
|
|
|
|
|
void __init setup_pit_timer(void)
|
|
|
|
{
|
2011-06-09 07:08:27 -06:00
|
|
|
clockevent_i8253_init(true);
|
2007-10-11 16:46:10 -06:00
|
|
|
setup_irq(0, &irq0);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int __init init_pit_clocksource(void)
|
|
|
|
{
|
|
|
|
if (num_possible_cpus() > 1) /* PIT does not scale! */
|
|
|
|
return 0;
|
|
|
|
|
2011-05-08 12:03:03 -06:00
|
|
|
return clocksource_i8253_init();
|
2007-10-11 16:46:10 -06:00
|
|
|
}
|
|
|
|
arch_initcall(init_pit_clocksource);
|