Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/drzeus/mmc
[linux-2.6] / 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 /*
17  * Scheduler clock - returns current time in nanosec units.
18  */
19 unsigned long long sched_clock(void)
20 {
21         return (unsigned long long)jiffies_64 * (NSEC_PER_SEC / HZ);
22 }
23
24 void timer_handler(int sig, struct uml_pt_regs *regs)
25 {
26         unsigned long flags;
27
28         local_irq_save(flags);
29         do_IRQ(TIMER_IRQ, regs);
30         local_irq_restore(flags);
31 }
32
33 static void itimer_set_mode(enum clock_event_mode mode,
34                             struct clock_event_device *evt)
35 {
36         switch (mode) {
37         case CLOCK_EVT_MODE_PERIODIC:
38                 set_interval();
39                 break;
40
41         case CLOCK_EVT_MODE_SHUTDOWN:
42         case CLOCK_EVT_MODE_UNUSED:
43         case CLOCK_EVT_MODE_ONESHOT:
44                 disable_timer();
45                 break;
46
47         case CLOCK_EVT_MODE_RESUME:
48                 break;
49         }
50 }
51
52 static int itimer_next_event(unsigned long delta,
53                              struct clock_event_device *evt)
54 {
55         return timer_one_shot(delta + 1);
56 }
57
58 static struct clock_event_device itimer_clockevent = {
59         .name           = "itimer",
60         .rating         = 250,
61         .cpumask        = CPU_MASK_ALL,
62         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
63         .set_mode       = itimer_set_mode,
64         .set_next_event = itimer_next_event,
65         .shift          = 32,
66         .irq            = 0,
67 };
68
69 static irqreturn_t um_timer(int irq, void *dev)
70 {
71         (*itimer_clockevent.event_handler)(&itimer_clockevent);
72
73         return IRQ_HANDLED;
74 }
75
76 static cycle_t itimer_read(void)
77 {
78         return os_nsecs() / 1000;
79 }
80
81 static struct clocksource itimer_clocksource = {
82         .name           = "itimer",
83         .rating         = 300,
84         .read           = itimer_read,
85         .mask           = CLOCKSOURCE_MASK(64),
86         .mult           = 1000,
87         .shift          = 0,
88         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
89 };
90
91 static void __init setup_itimer(void)
92 {
93         int err;
94
95         err = request_irq(TIMER_IRQ, um_timer, IRQF_DISABLED, "timer", NULL);
96         if (err != 0)
97                 printk(KERN_ERR "register_timer : request_irq failed - "
98                        "errno = %d\n", -err);
99
100         itimer_clockevent.mult = div_sc(HZ, NSEC_PER_SEC, 32);
101         itimer_clockevent.max_delta_ns =
102                 clockevent_delta2ns(60 * HZ, &itimer_clockevent);
103         itimer_clockevent.min_delta_ns =
104                 clockevent_delta2ns(1, &itimer_clockevent);
105         err = clocksource_register(&itimer_clocksource);
106         if (err) {
107                 printk(KERN_ERR "clocksource_register returned %d\n", err);
108                 return;
109         }
110         clockevents_register_device(&itimer_clockevent);
111 }
112
113 void __init time_init(void)
114 {
115         long long nsecs;
116
117         timer_init();
118
119         nsecs = os_nsecs();
120         set_normalized_timespec(&wall_to_monotonic, -nsecs / NSEC_PER_SEC,
121                                 -nsecs % NSEC_PER_SEC);
122         set_normalized_timespec(&xtime, nsecs / NSEC_PER_SEC,
123                                 nsecs % NSEC_PER_SEC);
124         late_time_init = setup_itimer;
125 }