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 /* this needs a better home */
41 DEFINE_SPINLOCK(rtc_lock);
43 #ifdef CONFIG_SA1100_RTC_MODULE
44 EXPORT_SYMBOL(rtc_lock);
47 /* change this if you have some constant time drift */
48 #define USECS_PER_JIFFY (1000000/HZ)
51 unsigned long profile_pc(struct pt_regs *regs)
53 unsigned long fp, pc = instruction_pointer(regs);
55 if (in_lock_functions(pc)) {
57 pc = pc_pointer(((unsigned long *)fp)[-1]);
62 EXPORT_SYMBOL(profile_pc);
66 * hook for setting the RTC's idea of the current time.
70 #ifndef CONFIG_GENERIC_TIME
71 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 #ifndef CONFIG_GENERIC_TIME
234 void do_gettimeofday(struct timeval *tv)
238 unsigned long usec, sec;
241 seq = read_seqbegin_irqsave(&xtime_lock, flags);
242 usec = system_timer->offset();
244 usec += xtime.tv_nsec / 1000;
245 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
247 /* usec may have gone up a lot: be safe */
248 while (usec >= 1000000) {
257 EXPORT_SYMBOL(do_gettimeofday);
259 int do_settimeofday(struct timespec *tv)
261 time_t wtm_sec, sec = tv->tv_sec;
262 long wtm_nsec, nsec = tv->tv_nsec;
264 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
267 write_seqlock_irq(&xtime_lock);
269 * This is revolting. We need to set "xtime" correctly. However, the
270 * value in this location is the value at the most recent update of
271 * wall time. Discover what correction gettimeofday() would have
272 * done, and then undo it!
274 nsec -= system_timer->offset() * NSEC_PER_USEC;
276 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
277 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
279 set_normalized_timespec(&xtime, sec, nsec);
280 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
283 write_sequnlock_irq(&xtime_lock);
288 EXPORT_SYMBOL(do_settimeofday);
289 #endif /* !CONFIG_GENERIC_TIME */
292 * save_time_delta - Save the offset between system time and RTC time
293 * @delta: pointer to timespec to store delta
294 * @rtc: pointer to timespec for current RTC time
296 * Return a delta between the system time and the RTC time, such
297 * that system time can be restored later with restore_time_delta()
299 void save_time_delta(struct timespec *delta, struct timespec *rtc)
301 set_normalized_timespec(delta,
302 xtime.tv_sec - rtc->tv_sec,
303 xtime.tv_nsec - rtc->tv_nsec);
305 EXPORT_SYMBOL(save_time_delta);
308 * restore_time_delta - Restore the current system time
309 * @delta: delta returned by save_time_delta()
310 * @rtc: pointer to timespec for current RTC time
312 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
316 set_normalized_timespec(&ts,
317 delta->tv_sec + rtc->tv_sec,
318 delta->tv_nsec + rtc->tv_nsec);
320 do_settimeofday(&ts);
322 EXPORT_SYMBOL(restore_time_delta);
325 * Kernel system timer support.
327 void timer_tick(struct pt_regs *regs)
329 profile_tick(CPU_PROFILING, regs);
334 update_process_times(user_mode(regs));
339 static int timer_suspend(struct sys_device *dev, pm_message_t state)
341 struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
343 if (timer->suspend != NULL)
349 static int timer_resume(struct sys_device *dev)
351 struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
353 if (timer->resume != NULL)
359 #define timer_suspend NULL
360 #define timer_resume NULL
363 static struct sysdev_class timer_sysclass = {
364 set_kset_name("timer"),
365 .suspend = timer_suspend,
366 .resume = timer_resume,
369 #ifdef CONFIG_NO_IDLE_HZ
370 static int timer_dyn_tick_enable(void)
372 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
377 spin_lock_irqsave(&dyn_tick->lock, flags);
379 if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
380 ret = dyn_tick->enable();
383 dyn_tick->state |= DYN_TICK_ENABLED;
385 spin_unlock_irqrestore(&dyn_tick->lock, flags);
391 static int timer_dyn_tick_disable(void)
393 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
398 spin_lock_irqsave(&dyn_tick->lock, flags);
400 if (dyn_tick->state & DYN_TICK_ENABLED) {
401 ret = dyn_tick->disable();
404 dyn_tick->state &= ~DYN_TICK_ENABLED;
406 spin_unlock_irqrestore(&dyn_tick->lock, flags);
413 * Reprogram the system timer for at least the calculated time interval.
414 * This function should be called from the idle thread with IRQs disabled,
415 * immediately before sleeping.
417 void timer_dyn_reprogram(void)
419 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
420 unsigned long next, seq, flags;
425 spin_lock_irqsave(&dyn_tick->lock, flags);
426 if (dyn_tick->state & DYN_TICK_ENABLED) {
427 next = next_timer_interrupt();
429 seq = read_seqbegin(&xtime_lock);
430 dyn_tick->reprogram(next - jiffies);
431 } while (read_seqretry(&xtime_lock, seq));
433 spin_unlock_irqrestore(&dyn_tick->lock, flags);
436 static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
438 return sprintf(buf, "%i\n",
439 (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
442 static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,
445 unsigned int enable = simple_strtoul(buf, NULL, 2);
448 timer_dyn_tick_enable();
450 timer_dyn_tick_disable();
454 static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
457 * dyntick=enable|disable
459 static char dyntick_str[4] __initdata = "";
461 static int __init dyntick_setup(char *str)
464 strlcpy(dyntick_str, str, sizeof(dyntick_str));
468 __setup("dyntick=", dyntick_setup);
471 static int __init timer_init_sysfs(void)
473 int ret = sysdev_class_register(&timer_sysclass);
475 system_timer->dev.cls = &timer_sysclass;
476 ret = sysdev_register(&system_timer->dev);
479 #ifdef CONFIG_NO_IDLE_HZ
480 if (ret == 0 && system_timer->dyn_tick) {
481 ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick);
484 * Turn on dynamic tick after calibrate delay
485 * for correct bogomips
487 if (ret == 0 && dyntick_str[0] == 'e')
488 ret = timer_dyn_tick_enable();
495 device_initcall(timer_init_sysfs);
497 void __init time_init(void)
499 #ifndef CONFIG_GENERIC_TIME
500 if (system_timer->offset == NULL)
501 system_timer->offset = dummy_gettimeoffset;
503 system_timer->init();
505 #ifdef CONFIG_NO_IDLE_HZ
506 if (system_timer->dyn_tick)
507 system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED;