linux/arch/um/kernel/time.c
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   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 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
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