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 #ifndef CONFIG_GENERIC_TIME
73 static unsigned long dummy_gettimeoffset(void)
80 * Scheduler clock - returns current time in nanosec units.
81 * This is the default implementation. Sub-architecture
82 * implementations can override this.
84 unsigned long long __attribute__((weak)) sched_clock(void)
86 return (unsigned long long)jiffies * (1000000000 / HZ);
89 static unsigned long next_rtc_update;
92 * If we have an externally synchronized linux clock, then update
93 * CMOS clock accordingly every ~11 minutes. set_rtc() has to be
94 * called as close as possible to 500 ms before the new second
97 static inline void do_set_rtc(void)
99 if (!ntp_synced() || set_rtc == NULL)
102 if (next_rtc_update &&
103 time_before((unsigned long)xtime.tv_sec, next_rtc_update))
106 if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
107 xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
112 * rtc update failed. Try again in 60s
114 next_rtc_update = xtime.tv_sec + 60;
116 next_rtc_update = xtime.tv_sec + 660;
121 static void dummy_leds_event(led_event_t evt)
125 void (*leds_event)(led_event_t) = dummy_leds_event;
127 struct leds_evt_name {
133 static const struct leds_evt_name evt_names[] = {
134 { "amber", led_amber_on, led_amber_off },
135 { "blue", led_blue_on, led_blue_off },
136 { "green", led_green_on, led_green_off },
137 { "red", led_red_on, led_red_off },
140 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
142 int ret = -EINVAL, len = strcspn(buf, " ");
144 if (len > 0 && buf[len] == '\0')
147 if (strncmp(buf, "claim", len) == 0) {
148 leds_event(led_claim);
150 } else if (strncmp(buf, "release", len) == 0) {
151 leds_event(led_release);
156 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
157 if (strlen(evt_names[i].name) != len ||
158 strncmp(buf, evt_names[i].name, len) != 0)
160 if (strncmp(buf+len, " on", 3) == 0) {
161 leds_event(evt_names[i].on);
163 } else if (strncmp(buf+len, " off", 4) == 0) {
164 leds_event(evt_names[i].off);
173 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
175 static int leds_suspend(struct sys_device *dev, pm_message_t state)
177 leds_event(led_stop);
181 static int leds_resume(struct sys_device *dev)
183 leds_event(led_start);
187 static int leds_shutdown(struct sys_device *dev)
189 leds_event(led_halted);
193 static struct sysdev_class leds_sysclass = {
194 set_kset_name("leds"),
195 .shutdown = leds_shutdown,
196 .suspend = leds_suspend,
197 .resume = leds_resume,
200 static struct sys_device leds_device = {
202 .cls = &leds_sysclass,
205 static int __init leds_init(void)
208 ret = sysdev_class_register(&leds_sysclass);
210 ret = sysdev_register(&leds_device);
212 ret = sysdev_create_file(&leds_device, &attr_event);
216 device_initcall(leds_init);
218 EXPORT_SYMBOL(leds_event);
221 #ifdef CONFIG_LEDS_TIMER
222 static inline void do_leds(void)
224 static unsigned int count = 50;
228 leds_event(led_timer);
235 #ifndef CONFIG_GENERIC_TIME
236 void do_gettimeofday(struct timeval *tv)
240 unsigned long usec, sec, lost;
243 seq = read_seqbegin_irqsave(&xtime_lock, flags);
244 usec = system_timer->offset();
246 lost = jiffies - wall_jiffies;
248 usec += lost * USECS_PER_JIFFY;
251 usec += xtime.tv_nsec / 1000;
252 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
254 /* usec may have gone up a lot: be safe */
255 while (usec >= 1000000) {
264 EXPORT_SYMBOL(do_gettimeofday);
266 int do_settimeofday(struct timespec *tv)
268 time_t wtm_sec, sec = tv->tv_sec;
269 long wtm_nsec, nsec = tv->tv_nsec;
271 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
274 write_seqlock_irq(&xtime_lock);
276 * This is revolting. We need to set "xtime" correctly. However, the
277 * value in this location is the value at the most recent update of
278 * wall time. Discover what correction gettimeofday() would have
279 * done, and then undo it!
281 nsec -= system_timer->offset() * NSEC_PER_USEC;
282 nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
284 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
285 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
287 set_normalized_timespec(&xtime, sec, nsec);
288 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
291 write_sequnlock_irq(&xtime_lock);
296 EXPORT_SYMBOL(do_settimeofday);
297 #endif /* !CONFIG_GENERIC_TIME */
300 * save_time_delta - Save the offset between system time and RTC time
301 * @delta: pointer to timespec to store delta
302 * @rtc: pointer to timespec for current RTC time
304 * Return a delta between the system time and the RTC time, such
305 * that system time can be restored later with restore_time_delta()
307 void save_time_delta(struct timespec *delta, struct timespec *rtc)
309 set_normalized_timespec(delta,
310 xtime.tv_sec - rtc->tv_sec,
311 xtime.tv_nsec - rtc->tv_nsec);
313 EXPORT_SYMBOL(save_time_delta);
316 * restore_time_delta - Restore the current system time
317 * @delta: delta returned by save_time_delta()
318 * @rtc: pointer to timespec for current RTC time
320 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
324 set_normalized_timespec(&ts,
325 delta->tv_sec + rtc->tv_sec,
326 delta->tv_nsec + rtc->tv_nsec);
328 do_settimeofday(&ts);
330 EXPORT_SYMBOL(restore_time_delta);
333 * Kernel system timer support.
335 void timer_tick(struct pt_regs *regs)
337 profile_tick(CPU_PROFILING, regs);
342 update_process_times(user_mode(regs));
347 static int timer_suspend(struct sys_device *dev, pm_message_t state)
349 struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
351 if (timer->suspend != NULL)
357 static int timer_resume(struct sys_device *dev)
359 struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
361 if (timer->resume != NULL)
367 #define timer_suspend NULL
368 #define timer_resume NULL
371 static struct sysdev_class timer_sysclass = {
372 set_kset_name("timer"),
373 .suspend = timer_suspend,
374 .resume = timer_resume,
377 #ifdef CONFIG_NO_IDLE_HZ
378 static int timer_dyn_tick_enable(void)
380 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
385 spin_lock_irqsave(&dyn_tick->lock, flags);
387 if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
388 ret = dyn_tick->enable();
391 dyn_tick->state |= DYN_TICK_ENABLED;
393 spin_unlock_irqrestore(&dyn_tick->lock, flags);
399 static int timer_dyn_tick_disable(void)
401 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
406 spin_lock_irqsave(&dyn_tick->lock, flags);
408 if (dyn_tick->state & DYN_TICK_ENABLED) {
409 ret = dyn_tick->disable();
412 dyn_tick->state &= ~DYN_TICK_ENABLED;
414 spin_unlock_irqrestore(&dyn_tick->lock, flags);
421 * Reprogram the system timer for at least the calculated time interval.
422 * This function should be called from the idle thread with IRQs disabled,
423 * immediately before sleeping.
425 void timer_dyn_reprogram(void)
427 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
428 unsigned long next, seq, flags;
433 spin_lock_irqsave(&dyn_tick->lock, flags);
434 if (dyn_tick->state & DYN_TICK_ENABLED) {
435 next = next_timer_interrupt();
437 seq = read_seqbegin(&xtime_lock);
438 dyn_tick->reprogram(next - jiffies);
439 } while (read_seqretry(&xtime_lock, seq));
441 spin_unlock_irqrestore(&dyn_tick->lock, flags);
444 static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
446 return sprintf(buf, "%i\n",
447 (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
450 static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,
453 unsigned int enable = simple_strtoul(buf, NULL, 2);
456 timer_dyn_tick_enable();
458 timer_dyn_tick_disable();
462 static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
465 * dyntick=enable|disable
467 static char dyntick_str[4] __initdata = "";
469 static int __init dyntick_setup(char *str)
472 strlcpy(dyntick_str, str, sizeof(dyntick_str));
476 __setup("dyntick=", dyntick_setup);
479 static int __init timer_init_sysfs(void)
481 int ret = sysdev_class_register(&timer_sysclass);
483 system_timer->dev.cls = &timer_sysclass;
484 ret = sysdev_register(&system_timer->dev);
487 #ifdef CONFIG_NO_IDLE_HZ
488 if (ret == 0 && system_timer->dyn_tick) {
489 ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick);
492 * Turn on dynamic tick after calibrate delay
493 * for correct bogomips
495 if (ret == 0 && dyntick_str[0] == 'e')
496 ret = timer_dyn_tick_enable();
503 device_initcall(timer_init_sysfs);
505 void __init time_init(void)
507 #ifndef CONFIG_GENERIC_TIME
508 if (system_timer->offset == NULL)
509 system_timer->offset = dummy_gettimeoffset;
511 system_timer->init();
513 #ifdef CONFIG_NO_IDLE_HZ
514 if (system_timer->dyn_tick)
515 system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED;