2 * linux/arch/arm/kernel/time.c
4 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
5 * Modifications for ARM (C) 1994-2001 Russell King
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * This file contains the ARM-specific time handling details:
12 * reading the RTC at bootup, etc...
14 * 1994-07-02 Alan Modra
15 * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
16 * 1998-12-20 Updated NTP code according to technical memorandum Jan '96
17 * "A Kernel Model for Precision Timekeeping" by Dave Mills
19 #include <linux/module.h>
20 #include <linux/kernel.h>
21 #include <linux/interrupt.h>
22 #include <linux/time.h>
23 #include <linux/init.h>
24 #include <linux/smp.h>
25 #include <linux/timex.h>
26 #include <linux/errno.h>
27 #include <linux/profile.h>
28 #include <linux/sysdev.h>
29 #include <linux/timer.h>
32 #include <asm/thread_info.h>
33 #include <asm/mach/time.h>
38 struct sys_timer *system_timer;
40 extern unsigned long wall_jiffies;
42 /* this needs a better home */
43 DEFINE_SPINLOCK(rtc_lock);
45 #ifdef CONFIG_SA1100_RTC_MODULE
46 EXPORT_SYMBOL(rtc_lock);
49 /* change this if you have some constant time drift */
50 #define USECS_PER_JIFFY (1000000/HZ)
53 unsigned long profile_pc(struct pt_regs *regs)
55 unsigned long fp, pc = instruction_pointer(regs);
57 if (in_lock_functions(pc)) {
59 pc = pc_pointer(((unsigned long *)fp)[-1]);
64 EXPORT_SYMBOL(profile_pc);
68 * hook for setting the RTC's idea of the current time.
72 static unsigned long dummy_gettimeoffset(void)
78 * Scheduler clock - returns current time in nanosec units.
79 * This is the default implementation. Sub-architecture
80 * implementations can override this.
82 unsigned long long __attribute__((weak)) sched_clock(void)
84 return (unsigned long long)jiffies * (1000000000 / HZ);
87 static unsigned long next_rtc_update;
90 * If we have an externally synchronized linux clock, then update
91 * CMOS clock accordingly every ~11 minutes. set_rtc() has to be
92 * called as close as possible to 500 ms before the new second
95 static inline void do_set_rtc(void)
97 if (!ntp_synced() || set_rtc == NULL)
100 if (next_rtc_update &&
101 time_before((unsigned long)xtime.tv_sec, next_rtc_update))
104 if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
105 xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
110 * rtc update failed. Try again in 60s
112 next_rtc_update = xtime.tv_sec + 60;
114 next_rtc_update = xtime.tv_sec + 660;
119 static void dummy_leds_event(led_event_t evt)
123 void (*leds_event)(led_event_t) = dummy_leds_event;
125 struct leds_evt_name {
131 static const struct leds_evt_name evt_names[] = {
132 { "amber", led_amber_on, led_amber_off },
133 { "blue", led_blue_on, led_blue_off },
134 { "green", led_green_on, led_green_off },
135 { "red", led_red_on, led_red_off },
138 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
140 int ret = -EINVAL, len = strcspn(buf, " ");
142 if (len > 0 && buf[len] == '\0')
145 if (strncmp(buf, "claim", len) == 0) {
146 leds_event(led_claim);
148 } else if (strncmp(buf, "release", len) == 0) {
149 leds_event(led_release);
154 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
155 if (strlen(evt_names[i].name) != len ||
156 strncmp(buf, evt_names[i].name, len) != 0)
158 if (strncmp(buf+len, " on", 3) == 0) {
159 leds_event(evt_names[i].on);
161 } else if (strncmp(buf+len, " off", 4) == 0) {
162 leds_event(evt_names[i].off);
171 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
173 static int leds_suspend(struct sys_device *dev, pm_message_t state)
175 leds_event(led_stop);
179 static int leds_resume(struct sys_device *dev)
181 leds_event(led_start);
185 static int leds_shutdown(struct sys_device *dev)
187 leds_event(led_halted);
191 static struct sysdev_class leds_sysclass = {
192 set_kset_name("leds"),
193 .shutdown = leds_shutdown,
194 .suspend = leds_suspend,
195 .resume = leds_resume,
198 static struct sys_device leds_device = {
200 .cls = &leds_sysclass,
203 static int __init leds_init(void)
206 ret = sysdev_class_register(&leds_sysclass);
208 ret = sysdev_register(&leds_device);
210 ret = sysdev_create_file(&leds_device, &attr_event);
214 device_initcall(leds_init);
216 EXPORT_SYMBOL(leds_event);
219 #ifdef CONFIG_LEDS_TIMER
220 static inline void do_leds(void)
222 static unsigned int count = 50;
226 leds_event(led_timer);
233 void do_gettimeofday(struct timeval *tv)
237 unsigned long usec, sec, lost;
240 seq = read_seqbegin_irqsave(&xtime_lock, flags);
241 usec = system_timer->offset();
243 lost = jiffies - wall_jiffies;
245 usec += lost * USECS_PER_JIFFY;
248 usec += xtime.tv_nsec / 1000;
249 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
251 /* usec may have gone up a lot: be safe */
252 while (usec >= 1000000) {
261 EXPORT_SYMBOL(do_gettimeofday);
263 int do_settimeofday(struct timespec *tv)
265 time_t wtm_sec, sec = tv->tv_sec;
266 long wtm_nsec, nsec = tv->tv_nsec;
268 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
271 write_seqlock_irq(&xtime_lock);
273 * This is revolting. We need to set "xtime" correctly. However, the
274 * value in this location is the value at the most recent update of
275 * wall time. Discover what correction gettimeofday() would have
276 * done, and then undo it!
278 nsec -= system_timer->offset() * NSEC_PER_USEC;
279 nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
281 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
282 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
284 set_normalized_timespec(&xtime, sec, nsec);
285 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
288 write_sequnlock_irq(&xtime_lock);
293 EXPORT_SYMBOL(do_settimeofday);
296 * save_time_delta - Save the offset between system time and RTC time
297 * @delta: pointer to timespec to store delta
298 * @rtc: pointer to timespec for current RTC time
300 * Return a delta between the system time and the RTC time, such
301 * that system time can be restored later with restore_time_delta()
303 void save_time_delta(struct timespec *delta, struct timespec *rtc)
305 set_normalized_timespec(delta,
306 xtime.tv_sec - rtc->tv_sec,
307 xtime.tv_nsec - rtc->tv_nsec);
309 EXPORT_SYMBOL(save_time_delta);
312 * restore_time_delta - Restore the current system time
313 * @delta: delta returned by save_time_delta()
314 * @rtc: pointer to timespec for current RTC time
316 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
320 set_normalized_timespec(&ts,
321 delta->tv_sec + rtc->tv_sec,
322 delta->tv_nsec + rtc->tv_nsec);
324 do_settimeofday(&ts);
326 EXPORT_SYMBOL(restore_time_delta);
329 * Kernel system timer support.
331 void timer_tick(struct pt_regs *regs)
333 profile_tick(CPU_PROFILING, regs);
338 update_process_times(user_mode(regs));
343 static int timer_suspend(struct sys_device *dev, pm_message_t state)
345 struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
347 if (timer->suspend != NULL)
353 static int timer_resume(struct sys_device *dev)
355 struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
357 if (timer->resume != NULL)
363 #define timer_suspend NULL
364 #define timer_resume NULL
367 static struct sysdev_class timer_sysclass = {
368 set_kset_name("timer"),
369 .suspend = timer_suspend,
370 .resume = timer_resume,
373 #ifdef CONFIG_NO_IDLE_HZ
374 static int timer_dyn_tick_enable(void)
376 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
381 spin_lock_irqsave(&dyn_tick->lock, flags);
383 if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
384 ret = dyn_tick->enable();
387 dyn_tick->state |= DYN_TICK_ENABLED;
389 spin_unlock_irqrestore(&dyn_tick->lock, flags);
395 static int timer_dyn_tick_disable(void)
397 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
402 spin_lock_irqsave(&dyn_tick->lock, flags);
404 if (dyn_tick->state & DYN_TICK_ENABLED) {
405 ret = dyn_tick->disable();
408 dyn_tick->state &= ~DYN_TICK_ENABLED;
410 spin_unlock_irqrestore(&dyn_tick->lock, flags);
417 * Reprogram the system timer for at least the calculated time interval.
418 * This function should be called from the idle thread with IRQs disabled,
419 * immediately before sleeping.
421 void timer_dyn_reprogram(void)
423 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
424 unsigned long next, seq, flags;
429 spin_lock_irqsave(&dyn_tick->lock, flags);
430 if (dyn_tick->state & DYN_TICK_ENABLED) {
431 next = next_timer_interrupt();
433 seq = read_seqbegin(&xtime_lock);
434 dyn_tick->reprogram(next - jiffies);
435 } while (read_seqretry(&xtime_lock, seq));
437 spin_unlock_irqrestore(&dyn_tick->lock, flags);
440 static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
442 return sprintf(buf, "%i\n",
443 (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
446 static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,
449 unsigned int enable = simple_strtoul(buf, NULL, 2);
452 timer_dyn_tick_enable();
454 timer_dyn_tick_disable();
458 static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
461 * dyntick=enable|disable
463 static char dyntick_str[4] __initdata = "";
465 static int __init dyntick_setup(char *str)
468 strlcpy(dyntick_str, str, sizeof(dyntick_str));
472 __setup("dyntick=", dyntick_setup);
475 static int __init timer_init_sysfs(void)
477 int ret = sysdev_class_register(&timer_sysclass);
479 system_timer->dev.cls = &timer_sysclass;
480 ret = sysdev_register(&system_timer->dev);
483 #ifdef CONFIG_NO_IDLE_HZ
484 if (ret == 0 && system_timer->dyn_tick) {
485 ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick);
488 * Turn on dynamic tick after calibrate delay
489 * for correct bogomips
491 if (ret == 0 && dyntick_str[0] == 'e')
492 ret = timer_dyn_tick_enable();
499 device_initcall(timer_init_sysfs);
501 void __init time_init(void)
503 if (system_timer->offset == NULL)
504 system_timer->offset = dummy_gettimeoffset;
505 system_timer->init();
507 #ifdef CONFIG_NO_IDLE_HZ
508 if (system_timer->dyn_tick)
509 system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED;