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
timer_handler(int sig,struct uml_pt_regs * regs)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
itimer_set_mode(enum clock_event_mode mode,struct clock_event_device * evt)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
itimer_next_event(unsigned long delta,struct clock_event_device * evt)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
um_timer(int irq,void * dev)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
itimer_read(struct clocksource * cs)68 static cycle_t itimer_read(struct clocksource *cs)
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 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
79 };
80
setup_itimer(void)81 static 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
read_persistent_clock(struct timespec * ts)103 void 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
time_init(void)111 void __init time_init(void)
112 {
113 timer_init();
114 late_time_init = setup_itimer;
115 }
116