2 * arch/sh/kernel/time_32.c
4 * Copyright (C) 1999 Tetsuya Okada & Niibe Yutaka
5 * Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
6 * Copyright (C) 2002 - 2008 Paul Mundt
7 * Copyright (C) 2002 M. R. Brown <mrbrown@linux-sh.org>
9 * Some code taken from i386 version.
10 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/profile.h>
16 #include <linux/timex.h>
17 #include <linux/sched.h>
18 #include <linux/clockchips.h>
19 #include <linux/mc146818rtc.h> /* for rtc_lock */
20 #include <linux/platform_device.h>
21 #include <linux/smp.h>
22 #include <asm/clock.h>
24 #include <asm/timer.h>
27 struct sys_timer *sys_timer;
29 /* Move this somewhere more sensible.. */
30 DEFINE_SPINLOCK(rtc_lock);
31 EXPORT_SYMBOL(rtc_lock);
34 static void null_rtc_get_time(struct timespec *tv)
36 tv->tv_sec = mktime(2000, 1, 1, 0, 0, 0);
40 static int null_rtc_set_time(const time_t secs)
45 void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
46 int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;
48 #ifndef CONFIG_GENERIC_TIME
49 void do_gettimeofday(struct timeval *tv)
53 unsigned long usec, sec;
57 * Turn off IRQs when grabbing xtime_lock, so that
58 * the sys_timer get_offset code doesn't have to handle it.
60 seq = read_seqbegin_irqsave(&xtime_lock, flags);
61 usec = get_timer_offset();
63 usec += xtime.tv_nsec / NSEC_PER_USEC;
64 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
66 while (usec >= 1000000) {
74 EXPORT_SYMBOL(do_gettimeofday);
76 int do_settimeofday(struct timespec *tv)
78 time_t wtm_sec, sec = tv->tv_sec;
79 long wtm_nsec, nsec = tv->tv_nsec;
81 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
84 write_seqlock_irq(&xtime_lock);
86 * This is revolting. We need to set "xtime" correctly. However, the
87 * value in this location is the value at the most recent update of
88 * wall time. Discover what correction gettimeofday() would have
89 * made, and then undo it!
91 nsec -= get_timer_offset() * NSEC_PER_USEC;
93 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
94 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
96 set_normalized_timespec(&xtime, sec, nsec);
97 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
100 write_sequnlock_irq(&xtime_lock);
105 EXPORT_SYMBOL(do_settimeofday);
106 #endif /* !CONFIG_GENERIC_TIME */
108 /* last time the RTC clock got updated */
109 static long last_rtc_update;
112 * handle_timer_tick() needs to keep up the real-time clock,
113 * as well as call the "do_timer()" routine every clocktick
115 void handle_timer_tick(void)
118 profile_tick(CPU_PROFILING);
121 * Here we are in the timer irq handler. We just have irqs locally
122 * disabled but we don't know if the timer_bh is running on the other
123 * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
124 * the irq version of write_lock because as just said we have irq
125 * locally disabled. -arca
127 write_seqlock(&xtime_lock);
131 * If we have an externally synchronized Linux clock, then update
132 * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
133 * called as close as possible to 500 ms before the new second starts.
136 xtime.tv_sec > last_rtc_update + 660 &&
137 (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
138 (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
139 if (rtc_sh_set_time(xtime.tv_sec) == 0)
140 last_rtc_update = xtime.tv_sec;
142 /* do it again in 60s */
143 last_rtc_update = xtime.tv_sec - 600;
145 write_sequnlock(&xtime_lock);
148 update_process_times(user_mode(get_irq_regs()));
153 int timer_suspend(struct sys_device *dev, pm_message_t state)
155 struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
157 sys_timer->ops->stop();
162 int timer_resume(struct sys_device *dev)
164 struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
166 sys_timer->ops->start();
171 #define timer_suspend NULL
172 #define timer_resume NULL
175 static struct sysdev_class timer_sysclass = {
177 .suspend = timer_suspend,
178 .resume = timer_resume,
181 static int __init timer_init_sysfs(void)
188 ret = sysdev_class_register(&timer_sysclass);
192 sys_timer->dev.cls = &timer_sysclass;
193 return sysdev_register(&sys_timer->dev);
195 device_initcall(timer_init_sysfs);
197 void (*board_time_init)(void);
199 struct clocksource clocksource_sh = {
203 #ifdef CONFIG_GENERIC_TIME
204 unsigned long long sched_clock(void)
206 unsigned long long cycles;
208 /* jiffies based sched_clock if no clocksource is installed */
209 if (!clocksource_sh.rating)
210 return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ);
212 cycles = clocksource_sh.read(&clocksource_sh);
213 return cyc2ns(&clocksource_sh, cycles);
217 void __init time_init(void)
224 rtc_sh_get_time(&xtime);
225 set_normalized_timespec(&wall_to_monotonic,
226 -xtime.tv_sec, -xtime.tv_nsec);
228 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
229 local_timer_setup(smp_processor_id());
233 * Make sure all compiled-in early timers register themselves.
234 * Run probe() for one "earlytimer" device.
236 early_platform_driver_register_all("earlytimer");
237 if (early_platform_driver_probe("earlytimer", 1, 0))
241 * Find the timer to use as the system timer, it will be
242 * initialized for us.
244 sys_timer = get_sys_timer();
245 if (unlikely(!sys_timer))
246 panic("System timer missing.\n");
248 printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);