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>
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)
57 * hook for setting the RTC's idea of the current time.
61 static unsigned long dummy_gettimeoffset(void)
67 * hook for getting the time offset. Note that it is
68 * always called with interrupts disabled.
70 unsigned long (*gettimeoffset)(void) = dummy_gettimeoffset;
73 * Scheduler clock - returns current time in nanosec units.
74 * This is the default implementation. Sub-architecture
75 * implementations can override this.
77 unsigned long long __attribute__((weak)) sched_clock(void)
79 return (unsigned long long)jiffies * (1000000000 / HZ);
83 * Handle kernel profile stuff...
85 static inline void do_profile(struct pt_regs *regs)
90 if (!user_mode(regs) &&
93 unsigned long pc = instruction_pointer(regs);
96 pc -= (unsigned long)&_stext;
103 prof_buffer[pc] += 1;
107 static unsigned long next_rtc_update;
110 * If we have an externally synchronized linux clock, then update
111 * CMOS clock accordingly every ~11 minutes. set_rtc() has to be
112 * called as close as possible to 500 ms before the new second
115 static inline void do_set_rtc(void)
117 if (time_status & STA_UNSYNC || set_rtc == NULL)
120 if (next_rtc_update &&
121 time_before((unsigned long)xtime.tv_sec, next_rtc_update))
124 if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
125 xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
130 * rtc update failed. Try again in 60s
132 next_rtc_update = xtime.tv_sec + 60;
134 next_rtc_update = xtime.tv_sec + 660;
139 static void dummy_leds_event(led_event_t evt)
143 void (*leds_event)(led_event_t) = dummy_leds_event;
145 struct leds_evt_name {
151 static const struct leds_evt_name evt_names[] = {
152 { "amber", led_amber_on, led_amber_off },
153 { "blue", led_blue_on, led_blue_off },
154 { "green", led_green_on, led_green_off },
155 { "red", led_red_on, led_red_off },
158 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
160 int ret = -EINVAL, len = strcspn(buf, " ");
162 if (len > 0 && buf[len] == '\0')
165 if (strncmp(buf, "claim", len) == 0) {
166 leds_event(led_claim);
168 } else if (strncmp(buf, "release", len) == 0) {
169 leds_event(led_release);
174 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
175 if (strlen(evt_names[i].name) != len ||
176 strncmp(buf, evt_names[i].name, len) != 0)
178 if (strncmp(buf+len, " on", 3) == 0) {
179 leds_event(evt_names[i].on);
181 } else if (strncmp(buf+len, " off", 4) == 0) {
182 leds_event(evt_names[i].off);
191 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
193 static int leds_suspend(struct sys_device *dev, u32 state)
195 leds_event(led_stop);
199 static int leds_resume(struct sys_device *dev)
201 leds_event(led_start);
205 static int leds_shutdown(struct sys_device *dev)
207 leds_event(led_halted);
211 static struct sysdev_class leds_sysclass = {
212 set_kset_name("leds"),
213 .shutdown = leds_shutdown,
214 .suspend = leds_suspend,
215 .resume = leds_resume,
218 static struct sys_device leds_device = {
220 .cls = &leds_sysclass,
223 static int __init leds_init(void)
226 ret = sysdev_class_register(&leds_sysclass);
228 ret = sysdev_register(&leds_device);
230 ret = sysdev_create_file(&leds_device, &attr_event);
234 device_initcall(leds_init);
236 EXPORT_SYMBOL(leds_event);
239 #ifdef CONFIG_LEDS_TIMER
240 static inline void do_leds(void)
242 static unsigned int count = 50;
246 leds_event(led_timer);
253 void do_gettimeofday(struct timeval *tv)
257 unsigned long usec, sec, lost;
260 seq = read_seqbegin_irqsave(&xtime_lock, flags);
261 usec = gettimeoffset();
263 lost = jiffies - wall_jiffies;
265 usec += lost * USECS_PER_JIFFY;
268 usec += xtime.tv_nsec / 1000;
269 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
271 /* usec may have gone up a lot: be safe */
272 while (usec >= 1000000) {
281 EXPORT_SYMBOL(do_gettimeofday);
283 int do_settimeofday(struct timespec *tv)
285 time_t wtm_sec, sec = tv->tv_sec;
286 long wtm_nsec, nsec = tv->tv_nsec;
288 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
291 write_seqlock_irq(&xtime_lock);
293 * This is revolting. We need to set "xtime" correctly. However, the
294 * value in this location is the value at the most recent update of
295 * wall time. Discover what correction gettimeofday() would have
296 * done, and then undo it!
298 nsec -= gettimeoffset() * NSEC_PER_USEC;
299 nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
301 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
302 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
304 set_normalized_timespec(&xtime, sec, nsec);
305 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
307 time_adjust = 0; /* stop active adjtime() */
308 time_status |= STA_UNSYNC;
309 time_maxerror = NTP_PHASE_LIMIT;
310 time_esterror = NTP_PHASE_LIMIT;
311 write_sequnlock_irq(&xtime_lock);
316 EXPORT_SYMBOL(do_settimeofday);
318 void timer_tick(struct pt_regs *regs)
326 void (*init_arch_time)(void);
328 void __init time_init(void)