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>
36 #include <asm/thread_info.h>
37 #include <asm/mach/time.h>
39 u64 jiffies_64 = INITIAL_JIFFIES;
41 EXPORT_SYMBOL(jiffies_64);
43 extern unsigned long wall_jiffies;
45 /* this needs a better home */
46 spinlock_t rtc_lock = SPIN_LOCK_UNLOCKED;
48 #ifdef CONFIG_SA1100_RTC_MODULE
49 EXPORT_SYMBOL(rtc_lock);
52 /* change this if you have some constant time drift */
53 #define USECS_PER_JIFFY (1000000/HZ)
56 unsigned long profile_pc(struct pt_regs *regs)
58 unsigned long fp, pc = instruction_pointer(regs);
60 if (in_lock_functions(pc)) {
61 fp = thread_saved_fp(current);
62 pc = pc_pointer(((unsigned long *)fp)[-1]);
67 EXPORT_SYMBOL(profile_pc);
71 * hook for setting the RTC's idea of the current time.
75 static unsigned long dummy_gettimeoffset(void)
81 * hook for getting the time offset. Note that it is
82 * always called with interrupts disabled.
84 unsigned long (*gettimeoffset)(void) = dummy_gettimeoffset;
87 * Scheduler clock - returns current time in nanosec units.
88 * This is the default implementation. Sub-architecture
89 * implementations can override this.
91 unsigned long long __attribute__((weak)) sched_clock(void)
93 return (unsigned long long)jiffies * (1000000000 / HZ);
96 static unsigned long next_rtc_update;
99 * If we have an externally synchronized linux clock, then update
100 * CMOS clock accordingly every ~11 minutes. set_rtc() has to be
101 * called as close as possible to 500 ms before the new second
104 static inline void do_set_rtc(void)
106 if (time_status & STA_UNSYNC || set_rtc == NULL)
109 if (next_rtc_update &&
110 time_before((unsigned long)xtime.tv_sec, next_rtc_update))
113 if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
114 xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
119 * rtc update failed. Try again in 60s
121 next_rtc_update = xtime.tv_sec + 60;
123 next_rtc_update = xtime.tv_sec + 660;
128 static void dummy_leds_event(led_event_t evt)
132 void (*leds_event)(led_event_t) = dummy_leds_event;
134 struct leds_evt_name {
140 static const struct leds_evt_name evt_names[] = {
141 { "amber", led_amber_on, led_amber_off },
142 { "blue", led_blue_on, led_blue_off },
143 { "green", led_green_on, led_green_off },
144 { "red", led_red_on, led_red_off },
147 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
149 int ret = -EINVAL, len = strcspn(buf, " ");
151 if (len > 0 && buf[len] == '\0')
154 if (strncmp(buf, "claim", len) == 0) {
155 leds_event(led_claim);
157 } else if (strncmp(buf, "release", len) == 0) {
158 leds_event(led_release);
163 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
164 if (strlen(evt_names[i].name) != len ||
165 strncmp(buf, evt_names[i].name, len) != 0)
167 if (strncmp(buf+len, " on", 3) == 0) {
168 leds_event(evt_names[i].on);
170 } else if (strncmp(buf+len, " off", 4) == 0) {
171 leds_event(evt_names[i].off);
180 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
182 static int leds_suspend(struct sys_device *dev, u32 state)
184 leds_event(led_stop);
188 static int leds_resume(struct sys_device *dev)
190 leds_event(led_start);
194 static int leds_shutdown(struct sys_device *dev)
196 leds_event(led_halted);
200 static struct sysdev_class leds_sysclass = {
201 set_kset_name("leds"),
202 .shutdown = leds_shutdown,
203 .suspend = leds_suspend,
204 .resume = leds_resume,
207 static struct sys_device leds_device = {
209 .cls = &leds_sysclass,
212 static int __init leds_init(void)
215 ret = sysdev_class_register(&leds_sysclass);
217 ret = sysdev_register(&leds_device);
219 ret = sysdev_create_file(&leds_device, &attr_event);
223 device_initcall(leds_init);
225 EXPORT_SYMBOL(leds_event);
228 #ifdef CONFIG_LEDS_TIMER
229 static inline void do_leds(void)
231 static unsigned int count = 50;
235 leds_event(led_timer);
242 void do_gettimeofday(struct timeval *tv)
246 unsigned long usec, sec, lost;
249 seq = read_seqbegin_irqsave(&xtime_lock, flags);
250 usec = gettimeoffset();
252 lost = jiffies - wall_jiffies;
254 usec += lost * USECS_PER_JIFFY;
257 usec += xtime.tv_nsec / 1000;
258 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
260 /* usec may have gone up a lot: be safe */
261 while (usec >= 1000000) {
270 EXPORT_SYMBOL(do_gettimeofday);
272 int do_settimeofday(struct timespec *tv)
274 time_t wtm_sec, sec = tv->tv_sec;
275 long wtm_nsec, nsec = tv->tv_nsec;
277 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
280 write_seqlock_irq(&xtime_lock);
282 * This is revolting. We need to set "xtime" correctly. However, the
283 * value in this location is the value at the most recent update of
284 * wall time. Discover what correction gettimeofday() would have
285 * done, and then undo it!
287 nsec -= gettimeoffset() * NSEC_PER_USEC;
288 nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
290 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
291 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
293 set_normalized_timespec(&xtime, sec, nsec);
294 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
296 time_adjust = 0; /* stop active adjtime() */
297 time_status |= STA_UNSYNC;
298 time_maxerror = NTP_PHASE_LIMIT;
299 time_esterror = NTP_PHASE_LIMIT;
300 write_sequnlock_irq(&xtime_lock);
305 EXPORT_SYMBOL(do_settimeofday);
308 * save_time_delta - Save the offset between system time and RTC time
309 * @delta: pointer to timespec to store delta
310 * @rtc: pointer to timespec for current RTC time
312 * Return a delta between the system time and the RTC time, such
313 * that system time can be restored later with restore_time_delta()
315 void save_time_delta(struct timespec *delta, struct timespec *rtc)
317 set_normalized_timespec(delta,
318 xtime.tv_sec - rtc->tv_sec,
319 xtime.tv_nsec - rtc->tv_nsec);
321 EXPORT_SYMBOL(save_time_delta);
324 * restore_time_delta - Restore the current system time
325 * @delta: delta returned by save_time_delta()
326 * @rtc: pointer to timespec for current RTC time
328 void restore_time_delta(struct timespec *delta, struct timespec *rtc)
332 set_normalized_timespec(&ts,
333 delta->tv_sec + rtc->tv_sec,
334 delta->tv_nsec + rtc->tv_nsec);
336 do_settimeofday(&ts);
338 EXPORT_SYMBOL(restore_time_delta);
340 void timer_tick(struct pt_regs *regs)
342 profile_tick(CPU_PROFILING, regs);
348 void (*init_arch_time)(void);
350 void __init time_init(void)