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 } 126