1/*
2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
4 */
5
6#include <linux/clockchips.h>
7#include <linux/init.h>
8#include <linux/interrupt.h>
9#include <linux/jiffies.h>
10#include <linux/threads.h>
11#include <asm/irq.h>
12#include <asm/param.h>
13#include <kern_util.h>
14#include <os.h>
15
16void timer_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
17{
18	unsigned long flags;
19
20	local_irq_save(flags);
21	do_IRQ(TIMER_IRQ, regs);
22	local_irq_restore(flags);
23}
24
25static void itimer_set_mode(enum clock_event_mode mode,
26			    struct clock_event_device *evt)
27{
28	switch (mode) {
29	case CLOCK_EVT_MODE_PERIODIC:
30		set_interval();
31		break;
32
33	case CLOCK_EVT_MODE_SHUTDOWN:
34	case CLOCK_EVT_MODE_UNUSED:
35	case CLOCK_EVT_MODE_ONESHOT:
36		disable_timer();
37		break;
38
39	case CLOCK_EVT_MODE_RESUME:
40		break;
41	}
42}
43
44static int itimer_next_event(unsigned long delta,
45			     struct clock_event_device *evt)
46{
47	return timer_one_shot(delta + 1);
48}
49
50static struct clock_event_device itimer_clockevent = {
51	.name		= "itimer",
52	.rating		= 250,
53	.cpumask	= cpu_all_mask,
54	.features	= CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
55	.set_mode	= itimer_set_mode,
56	.set_next_event = itimer_next_event,
57	.shift		= 32,
58	.irq		= 0,
59};
60
61static irqreturn_t um_timer(int irq, void *dev)
62{
63	(*itimer_clockevent.event_handler)(&itimer_clockevent);
64
65	return IRQ_HANDLED;
66}
67
68static cycle_t itimer_read(struct clocksource *cs)
69{
70	return os_nsecs() / 1000;
71}
72
73static struct clocksource itimer_clocksource = {
74	.name		= "itimer",
75	.rating		= 300,
76	.read		= itimer_read,
77	.mask		= CLOCKSOURCE_MASK(64),
78	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
79};
80
81static void __init setup_itimer(void)
82{
83	int err;
84
85	err = request_irq(TIMER_IRQ, um_timer, 0, "timer", NULL);
86	if (err != 0)
87		printk(KERN_ERR "register_timer : request_irq failed - "
88		       "errno = %d\n", -err);
89
90	itimer_clockevent.mult = div_sc(HZ, NSEC_PER_SEC, 32);
91	itimer_clockevent.max_delta_ns =
92		clockevent_delta2ns(60 * HZ, &itimer_clockevent);
93	itimer_clockevent.min_delta_ns =
94		clockevent_delta2ns(1, &itimer_clockevent);
95	err = clocksource_register_hz(&itimer_clocksource, USEC_PER_SEC);
96	if (err) {
97		printk(KERN_ERR "clocksource_register_hz returned %d\n", err);
98		return;
99	}
100	clockevents_register_device(&itimer_clockevent);
101}
102
103void read_persistent_clock(struct timespec *ts)
104{
105	long long nsecs = os_nsecs();
106
107	set_normalized_timespec(ts, nsecs / NSEC_PER_SEC,
108				nsecs % NSEC_PER_SEC);
109}
110
111void __init time_init(void)
112{
113	timer_init();
114	late_time_init = setup_itimer;
115}
116