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(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 .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 read_persistent_clock(struct timespec *ts) 106 { 107 long long nsecs = os_nsecs(); 108 109 set_normalized_timespec(ts, nsecs / NSEC_PER_SEC, 110 nsecs % NSEC_PER_SEC); 111 } 112 113 void __init time_init(void) 114 { 115 timer_init(); 116 late_time_init = setup_itimer; 117 } 118