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 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
  25 static int itimer_shutdown(struct clock_event_device *evt)
  26 {
  27         disable_timer();
  28         return 0;
  29 }
  30
  31 static int itimer_set_periodic(struct clock_event_device *evt)
  32 {
  33         set_interval();
  34         return 0;
  35 }
  36
  37 static int itimer_next_event(unsigned long delta,
  38                              struct clock_event_device *evt)
  39 {
  40         return timer_one_shot(delta + 1);
  41 }
  42
  43 static struct clock_event_device itimer_clockevent = {
  44         .name                   = "itimer",
  45         .rating                 = 250,
  46         .cpumask                = cpu_all_mask,
  47         .features               = CLOCK_EVT_FEAT_PERIODIC |
  48                                   CLOCK_EVT_FEAT_ONESHOT,
  49         .set_state_shutdown     = itimer_shutdown,
  50         .set_state_periodic     = itimer_set_periodic,
  51         .set_state_oneshot      = itimer_shutdown,
  52         .set_next_event         = itimer_next_event,
  53         .shift                  = 32,
  54         .irq                    = 0,
  55 };
  56
  57 static irqreturn_t um_timer(int irq, void *dev)
  58 {
  59         (*itimer_clockevent.event_handler)(&itimer_clockevent);
  60
  61         return IRQ_HANDLED;
  62 }
  63
  64 static cycle_t itimer_read(struct clocksource *cs)
  65 {
  66         return os_nsecs() / 1000;
  67 }
  68
  69 static struct clocksource itimer_clocksource = {
  70         .name           = "itimer",
  71         .rating         = 300,
  72         .read           = itimer_read,
  73         .mask           = CLOCKSOURCE_MASK(64),
  74         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  75 };
  76
  77 static void __init setup_itimer(void)
  78 {
  79         int err;
  80
  81         err = request_irq(TIMER_IRQ, um_timer, 0, "timer", NULL);
  82         if (err != 0)
  83                 printk(KERN_ERR "register_timer : request_irq failed - "
  84                        "errno = %d\n", -err);
  85
  86         itimer_clockevent.mult = div_sc(HZ, NSEC_PER_SEC, 32);
  87         itimer_clockevent.max_delta_ns =
  88                 clockevent_delta2ns(60 * HZ, &itimer_clockevent);
  89         itimer_clockevent.min_delta_ns =
  90                 clockevent_delta2ns(1, &itimer_clockevent);
  91         err = clocksource_register_hz(&itimer_clocksource, USEC_PER_SEC);
  92         if (err) {
  93                 printk(KERN_ERR "clocksource_register_hz returned %d\n", err);
  94                 return;
  95         }
  96         clockevents_register_device(&itimer_clockevent);
  97 }
  98
  99 void read_persistent_clock(struct timespec *ts)
 100 {
 101         long long nsecs = os_nsecs();
 102
 103         set_normalized_timespec(ts, nsecs / NSEC_PER_SEC,
 104                                 nsecs % NSEC_PER_SEC);
 105 }
 106
 107 void __init time_init(void)
 108 {
 109         timer_init();
 110         late_time_init = setup_itimer;
 111 }