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/*
* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#include "linux/clockchips.h"
#include "linux/interrupt.h"
#include "linux/jiffies.h"
#include "linux/threads.h"
#include "asm/irq.h"
#include "asm/param.h"
#include "kern_util.h"
#include "os.h"
/*
* Scheduler clock - returns current time in nanosec units.
*/
unsigned long long sched_clock(void)
{
return (unsigned long long)jiffies_64 * (1000000000 / HZ);
}
#ifdef CONFIG_UML_REAL_TIME_CLOCK
static unsigned long long prev_nsecs[NR_CPUS];
static long long delta[NR_CPUS]; /* Deviation per interval */
#endif
void timer_handler(int sig, struct uml_pt_regs *regs)
{
unsigned long long ticks = 0;
unsigned long flags;
#ifdef CONFIG_UML_REAL_TIME_CLOCK
int c = cpu();
if (prev_nsecs[c]) {
/* We've had 1 tick */
unsigned long long nsecs = os_nsecs();
delta[c] += nsecs - prev_nsecs[c];
prev_nsecs[c] = nsecs;
/* Protect against the host clock being set backwards */
if (delta[c] < 0)
delta[c] = 0;
ticks += (delta[c] * HZ) / BILLION;
delta[c] -= (ticks * BILLION) / HZ;
}
else prev_nsecs[c] = os_nsecs();
#else
ticks = 1;
#endif
local_irq_save(flags);
while (ticks > 0) {
do_IRQ(TIMER_IRQ, regs);
ticks--;
}
local_irq_restore(flags);
}
static void itimer_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
switch(mode) {
case CLOCK_EVT_MODE_PERIODIC:
set_interval();
break;
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_UNUSED:
disable_timer();
break;
case CLOCK_EVT_MODE_ONESHOT:
BUG();
break;
case CLOCK_EVT_MODE_RESUME:
break;
}
}
static struct clock_event_device itimer_clockevent = {
.name = "itimer",
.rating = 250,
.cpumask = CPU_MASK_ALL,
.features = CLOCK_EVT_FEAT_PERIODIC,
.set_mode = itimer_set_mode,
.set_next_event = NULL,
.shift = 32,
.irq = 0,
};
static irqreturn_t um_timer(int irq, void *dev)
{
(*itimer_clockevent.event_handler)(&itimer_clockevent);
return IRQ_HANDLED;
}
static cycle_t itimer_read(void)
{
return os_nsecs();
}
static struct clocksource itimer_clocksource = {
.name = "itimer",
.rating = 300,
.read = itimer_read,
.mask = CLOCKSOURCE_MASK(64),
.mult = 1,
.shift = 0,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static void __init setup_itimer(void)
{
int err;
err = request_irq(TIMER_IRQ, um_timer, IRQF_DISABLED, "timer", NULL);
if (err != 0)
printk(KERN_ERR "register_timer : request_irq failed - "
"errno = %d\n", -err);
itimer_clockevent.mult = div_sc(HZ, NSEC_PER_SEC, 32);
itimer_clockevent.max_delta_ns =
clockevent_delta2ns(60 * HZ, &itimer_clockevent);
itimer_clockevent.min_delta_ns =
clockevent_delta2ns(1, &itimer_clockevent);
err = clocksource_register(&itimer_clocksource);
if (err) {
printk(KERN_ERR "clocksource_register returned %d\n", err);
return;
}
clockevents_register_device(&itimer_clockevent);
}
extern void (*late_time_init)(void);
void __init time_init(void)
{
long long nsecs;
timer_init();
nsecs = os_nsecs();
set_normalized_timespec(&wall_to_monotonic, -nsecs / BILLION,
-nsecs % BILLION);
set_normalized_timespec(&xtime, nsecs / BILLION, nsecs % BILLION);
late_time_init = setup_itimer;
}
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