b13a87a3ec95cf7754fe0216660a2695e40b4d1d
[linux-2.6.git] / arch / um / kernel / time.c
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
16 void timer_handler(int sig, 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
25 static 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
44 static int itimer_next_event(unsigned long delta,
45                              struct clock_event_device *evt)
46 {
47         return timer_one_shot(delta + 1);
48 }
49
50 static 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
61 static irqreturn_t um_timer(int irq, void *dev)
62 {
63         (*itimer_clockevent.event_handler)(&itimer_clockevent);
64
65         return IRQ_HANDLED;
66 }
67
68 static cycle_t itimer_read(void)
69 {
70         return os_nsecs() / 1000;
71 }
72
73 static struct clocksource itimer_clocksource = {
74         .name           = "itimer",
75         .rating         = 300,
76         .read           = itimer_read,
77         .mask           = CLOCKSOURCE_MASK(64),
78         .mult           = 1000,
79         .shift          = 0,
80         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
81 };
82
83 static void __init setup_itimer(void)
84 {
85         int err;
86
87         err = request_irq(TIMER_IRQ, um_timer, IRQF_DISABLED, "timer", NULL);
88         if (err != 0)
89                 printk(KERN_ERR "register_timer : request_irq failed - "
90                        "errno = %d\n", -err);
91
92         itimer_clockevent.mult = div_sc(HZ, NSEC_PER_SEC, 32);
93         itimer_clockevent.max_delta_ns =
94                 clockevent_delta2ns(60 * HZ, &itimer_clockevent);
95         itimer_clockevent.min_delta_ns =
96                 clockevent_delta2ns(1, &itimer_clockevent);
97         err = clocksource_register(&itimer_clocksource);
98         if (err) {
99                 printk(KERN_ERR "clocksource_register returned %d\n", err);
100                 return;
101         }
102         clockevents_register_device(&itimer_clockevent);
103 }
104
105 void __init time_init(void)
106 {
107         long long nsecs;
108
109         timer_init();
110
111         nsecs = os_nsecs();
112         set_normalized_timespec(&wall_to_monotonic, -nsecs / NSEC_PER_SEC,
113                                 -nsecs % NSEC_PER_SEC);
114         set_normalized_timespec(&xtime, nsecs / NSEC_PER_SEC,
115                                 nsecs % NSEC_PER_SEC);
116         late_time_init = setup_itimer;
117 }