Linux 2.6.13-rc4
[linux-2.6/next.git] / arch / arm / kernel / time.c
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1 /*
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/config.h>
20 #include <linux/module.h>
21 #include <linux/kernel.h>
22 #include <linux/interrupt.h>
23 #include <linux/time.h>
24 #include <linux/init.h>
25 #include <linux/smp.h>
26 #include <linux/timex.h>
27 #include <linux/errno.h>
28 #include <linux/profile.h>
29 #include <linux/sysdev.h>
30 #include <linux/timer.h>
32 #include <asm/hardware.h>
33 #include <asm/io.h>
34 #include <asm/irq.h>
35 #include <asm/leds.h>
36 #include <asm/thread_info.h>
37 #include <asm/mach/time.h>
39 u64 jiffies_64 = INITIAL_JIFFIES;
41 EXPORT_SYMBOL(jiffies_64);
44 * Our system timer.
46 struct sys_timer *system_timer;
48 extern unsigned long wall_jiffies;
50 /* this needs a better home */
51 DEFINE_SPINLOCK(rtc_lock);
53 #ifdef CONFIG_SA1100_RTC_MODULE
54 EXPORT_SYMBOL(rtc_lock);
55 #endif
57 /* change this if you have some constant time drift */
58 #define USECS_PER_JIFFY (1000000/HZ)
60 #ifdef CONFIG_SMP
61 unsigned long profile_pc(struct pt_regs *regs)
63 unsigned long fp, pc = instruction_pointer(regs);
65 if (in_lock_functions(pc)) {
66 fp = regs->ARM_fp;
67 pc = pc_pointer(((unsigned long *)fp)[-1]);
70 return pc;
72 EXPORT_SYMBOL(profile_pc);
73 #endif
76 * hook for setting the RTC's idea of the current time.
78 int (*set_rtc)(void);
80 static unsigned long dummy_gettimeoffset(void)
82 return 0;
86 * Scheduler clock - returns current time in nanosec units.
87 * This is the default implementation. Sub-architecture
88 * implementations can override this.
90 unsigned long long __attribute__((weak)) sched_clock(void)
92 return (unsigned long long)jiffies * (1000000000 / HZ);
95 static unsigned long next_rtc_update;
98 * If we have an externally synchronized linux clock, then update
99 * CMOS clock accordingly every ~11 minutes. set_rtc() has to be
100 * called as close as possible to 500 ms before the new second
101 * starts.
103 static inline void do_set_rtc(void)
105 if (time_status & STA_UNSYNC || set_rtc == NULL)
106 return;
108 if (next_rtc_update &&
109 time_before((unsigned long)xtime.tv_sec, next_rtc_update))
110 return;
112 if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
113 xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
114 return;
116 if (set_rtc())
118 * rtc update failed. Try again in 60s
120 next_rtc_update = xtime.tv_sec + 60;
121 else
122 next_rtc_update = xtime.tv_sec + 660;
125 #ifdef CONFIG_LEDS
127 static void dummy_leds_event(led_event_t evt)
131 void (*leds_event)(led_event_t) = dummy_leds_event;
133 struct leds_evt_name {
134 const char name[8];
135 int on;
136 int off;
139 static const struct leds_evt_name evt_names[] = {
140 { "amber", led_amber_on, led_amber_off },
141 { "blue", led_blue_on, led_blue_off },
142 { "green", led_green_on, led_green_off },
143 { "red", led_red_on, led_red_off },
146 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
148 int ret = -EINVAL, len = strcspn(buf, " ");
150 if (len > 0 && buf[len] == '\0')
151 len--;
153 if (strncmp(buf, "claim", len) == 0) {
154 leds_event(led_claim);
155 ret = size;
156 } else if (strncmp(buf, "release", len) == 0) {
157 leds_event(led_release);
158 ret = size;
159 } else {
160 int i;
162 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
163 if (strlen(evt_names[i].name) != len ||
164 strncmp(buf, evt_names[i].name, len) != 0)
165 continue;
166 if (strncmp(buf+len, " on", 3) == 0) {
167 leds_event(evt_names[i].on);
168 ret = size;
169 } else if (strncmp(buf+len, " off", 4) == 0) {
170 leds_event(evt_names[i].off);
171 ret = size;
173 break;
176 return ret;
179 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
181 static int leds_suspend(struct sys_device *dev, pm_message_t state)
183 leds_event(led_stop);
184 return 0;
187 static int leds_resume(struct sys_device *dev)
189 leds_event(led_start);
190 return 0;
193 static int leds_shutdown(struct sys_device *dev)
195 leds_event(led_halted);
196 return 0;
199 static struct sysdev_class leds_sysclass = {
200 set_kset_name("leds"),
201 .shutdown = leds_shutdown,
202 .suspend = leds_suspend,
203 .resume = leds_resume,
206 static struct sys_device leds_device = {
207 .id = 0,
208 .cls = &leds_sysclass,
211 static int __init leds_init(void)
213 int ret;
214 ret = sysdev_class_register(&leds_sysclass);
215 if (ret == 0)
216 ret = sysdev_register(&leds_device);
217 if (ret == 0)
218 ret = sysdev_create_file(&leds_device, &attr_event);
219 return ret;
222 device_initcall(leds_init);
224 EXPORT_SYMBOL(leds_event);
225 #endif
227 #ifdef CONFIG_LEDS_TIMER
228 static inline void do_leds(void)
230 static unsigned int count = 50;
232 if (--count == 0) {
233 count = 50;
234 leds_event(led_timer);
237 #else
238 #define do_leds()
239 #endif
241 void do_gettimeofday(struct timeval *tv)
243 unsigned long flags;
244 unsigned long seq;
245 unsigned long usec, sec, lost;
247 do {
248 seq = read_seqbegin_irqsave(&xtime_lock, flags);
249 usec = system_timer->offset();
251 lost = jiffies - wall_jiffies;
252 if (lost)
253 usec += lost * USECS_PER_JIFFY;
255 sec = xtime.tv_sec;
256 usec += xtime.tv_nsec / 1000;
257 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
259 /* usec may have gone up a lot: be safe */
260 while (usec >= 1000000) {
261 usec -= 1000000;
262 sec++;
265 tv->tv_sec = sec;
266 tv->tv_usec = usec;
269 EXPORT_SYMBOL(do_gettimeofday);
271 int do_settimeofday(struct timespec *tv)
273 time_t wtm_sec, sec = tv->tv_sec;
274 long wtm_nsec, nsec = tv->tv_nsec;
276 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
277 return -EINVAL;
279 write_seqlock_irq(&xtime_lock);
281 * This is revolting. We need to set "xtime" correctly. However, the
282 * value in this location is the value at the most recent update of
283 * wall time. Discover what correction gettimeofday() would have
284 * done, and then undo it!
286 nsec -= system_timer->offset() * NSEC_PER_USEC;
287 nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
289 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
290 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
292 set_normalized_timespec(&xtime, sec, nsec);
293 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
295 time_adjust = 0; /* stop active adjtime() */
296 time_status |= STA_UNSYNC;
297 time_maxerror = NTP_PHASE_LIMIT;
298 time_esterror = NTP_PHASE_LIMIT;
299 write_sequnlock_irq(&xtime_lock);
300 clock_was_set();
301 return 0;
304 EXPORT_SYMBOL(do_settimeofday);
307 * save_time_delta - Save the offset between system time and RTC time
308 * @delta: pointer to timespec to store delta
309 * @rtc: pointer to timespec for current RTC time
311 * Return a delta between the system time and the RTC time, such
312 * that system time can be restored later with restore_time_delta()
314 void save_time_delta(struct timespec *delta, struct timespec *rtc)
316 set_normalized_timespec(delta,
317 xtime.tv_sec - rtc->tv_sec,
318 xtime.tv_nsec - rtc->tv_nsec);
320 EXPORT_SYMBOL(save_time_delta);
323 * restore_time_delta - Restore the current system time
324 * @delta: delta returned by save_time_delta()
325 * @rtc: pointer to timespec for current RTC time
327 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
329 struct timespec ts;
331 set_normalized_timespec(&ts,
332 delta->tv_sec + rtc->tv_sec,
333 delta->tv_nsec + rtc->tv_nsec);
335 do_settimeofday(&ts);
337 EXPORT_SYMBOL(restore_time_delta);
340 * Kernel system timer support.
342 void timer_tick(struct pt_regs *regs)
344 profile_tick(CPU_PROFILING, regs);
345 do_leds();
346 do_set_rtc();
347 do_timer(regs);
348 #ifndef CONFIG_SMP
349 update_process_times(user_mode(regs));
350 #endif
353 #ifdef CONFIG_PM
354 static int timer_suspend(struct sys_device *dev, pm_message_t state)
356 struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
358 if (timer->suspend != NULL)
359 timer->suspend();
361 return 0;
364 static int timer_resume(struct sys_device *dev)
366 struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
368 if (timer->resume != NULL)
369 timer->resume();
371 return 0;
373 #else
374 #define timer_suspend NULL
375 #define timer_resume NULL
376 #endif
378 static struct sysdev_class timer_sysclass = {
379 set_kset_name("timer"),
380 .suspend = timer_suspend,
381 .resume = timer_resume,
384 #ifdef CONFIG_NO_IDLE_HZ
385 static int timer_dyn_tick_enable(void)
387 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
388 unsigned long flags;
389 int ret = -ENODEV;
391 if (dyn_tick) {
392 write_seqlock_irqsave(&xtime_lock, flags);
393 ret = 0;
394 if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
395 ret = dyn_tick->enable();
397 if (ret == 0)
398 dyn_tick->state |= DYN_TICK_ENABLED;
400 write_sequnlock_irqrestore(&xtime_lock, flags);
403 return ret;
406 static int timer_dyn_tick_disable(void)
408 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
409 unsigned long flags;
410 int ret = -ENODEV;
412 if (dyn_tick) {
413 write_seqlock_irqsave(&xtime_lock, flags);
414 ret = 0;
415 if (dyn_tick->state & DYN_TICK_ENABLED) {
416 ret = dyn_tick->disable();
418 if (ret == 0)
419 dyn_tick->state &= ~DYN_TICK_ENABLED;
421 write_sequnlock_irqrestore(&xtime_lock, flags);
424 return ret;
428 * Reprogram the system timer for at least the calculated time interval.
429 * This function should be called from the idle thread with IRQs disabled,
430 * immediately before sleeping.
432 void timer_dyn_reprogram(void)
434 struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
436 write_seqlock(&xtime_lock);
437 if (dyn_tick->state & DYN_TICK_ENABLED)
438 dyn_tick->reprogram(next_timer_interrupt() - jiffies);
439 write_sequnlock(&xtime_lock);
442 static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
444 return sprintf(buf, "%i\n",
445 (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
448 static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,
449 size_t count)
451 unsigned int enable = simple_strtoul(buf, NULL, 2);
453 if (enable)
454 timer_dyn_tick_enable();
455 else
456 timer_dyn_tick_disable();
458 return count;
460 static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
463 * dyntick=enable|disable
465 static char dyntick_str[4] __initdata = "";
467 static int __init dyntick_setup(char *str)
469 if (str)
470 strlcpy(dyntick_str, str, sizeof(dyntick_str));
471 return 1;
474 __setup("dyntick=", dyntick_setup);
475 #endif
477 static int __init timer_init_sysfs(void)
479 int ret = sysdev_class_register(&timer_sysclass);
480 if (ret == 0) {
481 system_timer->dev.cls = &timer_sysclass;
482 ret = sysdev_register(&system_timer->dev);
485 #ifdef CONFIG_NO_IDLE_HZ
486 if (ret == 0 && system_timer->dyn_tick) {
487 ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick);
490 * Turn on dynamic tick after calibrate delay
491 * for correct bogomips
493 if (ret == 0 && dyntick_str[0] == 'e')
494 ret = timer_dyn_tick_enable();
496 #endif
498 return ret;
501 device_initcall(timer_init_sysfs);
503 void __init time_init(void)
505 if (system_timer->offset == NULL)
506 system_timer->offset = dummy_gettimeoffset;
507 system_timer->init();