2 * arch/sh/kernel/time.c
4 * Copyright (C) 1999 Tetsuya Okada & Niibe Yutaka
5 * Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
6 * Copyright (C) 2002 - 2006 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 <asm/clock.h>
18 #include <asm/timer.h>
21 struct sys_timer *sys_timer;
23 /* Move this somewhere more sensible.. */
24 DEFINE_SPINLOCK(rtc_lock);
25 EXPORT_SYMBOL(rtc_lock);
28 static void null_rtc_get_time(struct timespec *tv)
30 tv->tv_sec = mktime(2000, 1, 1, 0, 0, 0);
34 static int null_rtc_set_time(const time_t secs)
39 void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
40 int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;
43 * Scheduler clock - returns current time in nanosec units.
45 unsigned long long __attribute__ ((weak)) sched_clock(void)
47 return (unsigned long long)jiffies * (1000000000 / HZ);
50 #ifndef CONFIG_GENERIC_TIME
51 void do_gettimeofday(struct timeval *tv)
55 unsigned long usec, sec;
59 * Turn off IRQs when grabbing xtime_lock, so that
60 * the sys_timer get_offset code doesn't have to handle it.
62 seq = read_seqbegin_irqsave(&xtime_lock, flags);
63 usec = get_timer_offset();
65 usec += xtime.tv_nsec / NSEC_PER_USEC;
66 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
68 while (usec >= 1000000) {
76 EXPORT_SYMBOL(do_gettimeofday);
78 int do_settimeofday(struct timespec *tv)
80 time_t wtm_sec, sec = tv->tv_sec;
81 long wtm_nsec, nsec = tv->tv_nsec;
83 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
86 write_seqlock_irq(&xtime_lock);
88 * This is revolting. We need to set "xtime" correctly. However, the
89 * value in this location is the value at the most recent update of
90 * wall time. Discover what correction gettimeofday() would have
91 * made, and then undo it!
93 nsec -= get_timer_offset() * NSEC_PER_USEC;
95 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
96 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
98 set_normalized_timespec(&xtime, sec, nsec);
99 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
102 write_sequnlock_irq(&xtime_lock);
107 EXPORT_SYMBOL(do_settimeofday);
108 #endif /* !CONFIG_GENERIC_TIME */
110 /* last time the RTC clock got updated */
111 static long last_rtc_update;
114 * handle_timer_tick() needs to keep up the real-time clock,
115 * as well as call the "do_timer()" routine every clocktick
117 void handle_timer_tick(void)
121 update_process_times(user_mode(get_irq_regs()));
124 profile_tick(CPU_PROFILING);
126 #ifdef CONFIG_HEARTBEAT
127 if (sh_mv.mv_heartbeat != NULL)
128 sh_mv.mv_heartbeat();
132 * If we have an externally synchronized Linux clock, then update
133 * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
134 * called as close as possible to 500 ms before the new second starts.
137 xtime.tv_sec > last_rtc_update + 660 &&
138 (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
139 (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
140 if (rtc_sh_set_time(xtime.tv_sec) == 0)
141 last_rtc_update = xtime.tv_sec;
143 /* do it again in 60s */
144 last_rtc_update = xtime.tv_sec - 600;
149 int timer_suspend(struct sys_device *dev, pm_message_t state)
151 struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
153 sys_timer->ops->stop();
158 int timer_resume(struct sys_device *dev)
160 struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
162 sys_timer->ops->start();
167 #define timer_suspend NULL
168 #define timer_resume NULL
171 static struct sysdev_class timer_sysclass = {
172 set_kset_name("timer"),
173 .suspend = timer_suspend,
174 .resume = timer_resume,
177 #ifdef CONFIG_NO_IDLE_HZ
178 static int timer_dyn_tick_enable(void)
180 struct dyn_tick_timer *dyn_tick = sys_timer->dyn_tick;
185 spin_lock_irqsave(&dyn_tick->lock, flags);
187 if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
188 ret = dyn_tick->enable();
191 dyn_tick->state |= DYN_TICK_ENABLED;
193 spin_unlock_irqrestore(&dyn_tick->lock, flags);
199 static int timer_dyn_tick_disable(void)
201 struct dyn_tick_timer *dyn_tick = sys_timer->dyn_tick;
206 spin_lock_irqsave(&dyn_tick->lock, flags);
208 if (dyn_tick->state & DYN_TICK_ENABLED) {
209 ret = dyn_tick->disable();
212 dyn_tick->state &= ~DYN_TICK_ENABLED;
214 spin_unlock_irqrestore(&dyn_tick->lock, flags);
221 * Reprogram the system timer for at least the calculated time interval.
222 * This function should be called from the idle thread with IRQs disabled,
223 * immediately before sleeping.
225 void timer_dyn_reprogram(void)
227 struct dyn_tick_timer *dyn_tick = sys_timer->dyn_tick;
228 unsigned long next, seq, flags;
233 spin_lock_irqsave(&dyn_tick->lock, flags);
234 if (dyn_tick->state & DYN_TICK_ENABLED) {
235 next = next_timer_interrupt();
237 seq = read_seqbegin(&xtime_lock);
238 dyn_tick->reprogram(next - jiffies);
239 } while (read_seqretry(&xtime_lock, seq));
241 spin_unlock_irqrestore(&dyn_tick->lock, flags);
244 static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
246 return sprintf(buf, "%i\n",
247 (sys_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
250 static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,
253 unsigned int enable = simple_strtoul(buf, NULL, 2);
256 timer_dyn_tick_enable();
258 timer_dyn_tick_disable();
262 static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
265 * dyntick=enable|disable
267 static char dyntick_str[4] __initdata = "";
269 static int __init dyntick_setup(char *str)
272 strlcpy(dyntick_str, str, sizeof(dyntick_str));
276 __setup("dyntick=", dyntick_setup);
279 static int __init timer_init_sysfs(void)
281 int ret = sysdev_class_register(&timer_sysclass);
285 sys_timer->dev.cls = &timer_sysclass;
286 ret = sysdev_register(&sys_timer->dev);
288 #ifdef CONFIG_NO_IDLE_HZ
289 if (ret == 0 && sys_timer->dyn_tick) {
290 ret = sysdev_create_file(&sys_timer->dev, &attr_dyn_tick);
293 * Turn on dynamic tick after calibrate delay
294 * for correct bogomips
296 if (ret == 0 && dyntick_str[0] == 'e')
297 ret = timer_dyn_tick_enable();
303 device_initcall(timer_init_sysfs);
305 void (*board_time_init)(void);
307 void __init time_init(void)
314 rtc_sh_get_time(&xtime);
315 set_normalized_timespec(&wall_to_monotonic,
316 -xtime.tv_sec, -xtime.tv_nsec);
319 * Find the timer to use as the system timer, it will be
320 * initialized for us.
322 sys_timer = get_sys_timer();
323 printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
325 #ifdef CONFIG_NO_IDLE_HZ
326 if (sys_timer->dyn_tick)
327 spin_lock_init(&sys_timer->dyn_tick->lock);
330 #if defined(CONFIG_SH_KGDB)
332 * Set up kgdb as requested. We do it here because the serial
333 * init uses the timer vars we just set up for figuring baud.