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>
31 #include <asm/hardware.h>
36 u64 jiffies_64 = INITIAL_JIFFIES;
38 EXPORT_SYMBOL(jiffies_64);
40 extern unsigned long wall_jiffies;
42 /* this needs a better home */
43 spinlock_t rtc_lock = SPIN_LOCK_UNLOCKED;
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)
52 static int dummy_set_rtc(void)
58 * hook for setting the RTC's idea of the current time.
60 int (*set_rtc)(void) = dummy_set_rtc;
62 static unsigned long dummy_gettimeoffset(void)
68 * hook for getting the time offset. Note that it is
69 * always called with interrupts disabled.
71 unsigned long (*gettimeoffset)(void) = dummy_gettimeoffset;
74 * Scheduler clock - returns current time in nanosec units.
75 * This is the default implementation. Sub-architecture
76 * implementations can override this.
78 unsigned long long __attribute__((weak)) sched_clock(void)
80 return (unsigned long long)jiffies * (1000000000 / HZ);
84 * Handle kernel profile stuff...
86 static inline void do_profile(struct pt_regs *regs)
91 if (!user_mode(regs) &&
94 unsigned long pc = instruction_pointer(regs);
97 pc -= (unsigned long)&_stext;
104 prof_buffer[pc] += 1;
108 static unsigned long next_rtc_update;
111 * If we have an externally synchronized linux clock, then update
112 * CMOS clock accordingly every ~11 minutes. set_rtc() has to be
113 * called as close as possible to 500 ms before the new second
116 static inline void do_set_rtc(void)
118 if (time_status & STA_UNSYNC || set_rtc == NULL)
121 if (next_rtc_update &&
122 time_before((unsigned long)xtime.tv_sec, next_rtc_update))
125 if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
126 xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
131 * rtc update failed. Try again in 60s
133 next_rtc_update = xtime.tv_sec + 60;
135 next_rtc_update = xtime.tv_sec + 660;
140 static void dummy_leds_event(led_event_t evt)
144 void (*leds_event)(led_event_t) = dummy_leds_event;
146 struct leds_evt_name {
152 static const struct leds_evt_name evt_names[] = {
153 { "amber", led_amber_on, led_amber_off },
154 { "blue", led_blue_on, led_blue_off },
155 { "green", led_green_on, led_green_off },
156 { "red", led_red_on, led_red_off },
159 static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
161 int ret = -EINVAL, len = strcspn(buf, " ");
163 if (len > 0 && buf[len] == '\0')
166 if (strncmp(buf, "claim", len) == 0) {
167 leds_event(led_claim);
169 } else if (strncmp(buf, "release", len) == 0) {
170 leds_event(led_release);
175 for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
176 if (strlen(evt_names[i].name) != len ||
177 strncmp(buf, evt_names[i].name, len) != 0)
179 if (strncmp(buf+len, " on", 3) == 0) {
180 leds_event(evt_names[i].on);
182 } else if (strncmp(buf+len, " off", 4) == 0) {
183 leds_event(evt_names[i].off);
192 static SYSDEV_ATTR(event, 0200, NULL, leds_store);
194 static int leds_suspend(struct sys_device *dev, u32 state)
196 leds_event(led_stop);
200 static int leds_resume(struct sys_device *dev)
202 leds_event(led_start);
206 static int leds_shutdown(struct sys_device *dev)
208 leds_event(led_halted);
212 static struct sysdev_class leds_sysclass = {
213 set_kset_name("leds"),
214 .shutdown = leds_shutdown,
215 .suspend = leds_suspend,
216 .resume = leds_resume,
219 static struct sys_device leds_device = {
221 .cls = &leds_sysclass,
224 static int __init leds_init(void)
227 ret = sysdev_class_register(&leds_sysclass);
229 ret = sysdev_register(&leds_device);
231 ret = sysdev_create_file(&leds_device, &attr_event);
235 device_initcall(leds_init);
237 EXPORT_SYMBOL(leds_event);
240 #ifdef CONFIG_LEDS_TIMER
241 static void do_leds(void)
243 static unsigned int count = 50;
247 leds_event(led_timer);
254 void do_gettimeofday(struct timeval *tv)
258 unsigned long usec, sec, lost;
261 seq = read_seqbegin_irqsave(&xtime_lock, flags);
262 usec = gettimeoffset();
264 lost = jiffies - wall_jiffies;
266 usec += lost * USECS_PER_JIFFY;
269 usec += xtime.tv_nsec / 1000;
270 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
272 /* usec may have gone up a lot: be safe */
273 while (usec >= 1000000) {
282 EXPORT_SYMBOL(do_gettimeofday);
284 int do_settimeofday(struct timespec *tv)
286 time_t wtm_sec, sec = tv->tv_sec;
287 long wtm_nsec, nsec = tv->tv_nsec;
289 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
292 write_seqlock_irq(&xtime_lock);
294 * This is revolting. We need to set "xtime" correctly. However, the
295 * value in this location is the value at the most recent update of
296 * wall time. Discover what correction gettimeofday() would have
297 * done, and then undo it!
299 nsec -= gettimeoffset() * NSEC_PER_USEC;
300 nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
302 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
303 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
305 set_normalized_timespec(&xtime, sec, nsec);
306 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
308 time_adjust = 0; /* stop active adjtime() */
309 time_status |= STA_UNSYNC;
310 time_maxerror = NTP_PHASE_LIMIT;
311 time_esterror = NTP_PHASE_LIMIT;
312 write_sequnlock_irq(&xtime_lock);
317 EXPORT_SYMBOL(do_settimeofday);
319 static struct irqaction timer_irq = {
321 .flags = SA_INTERRUPT,
325 * Include architecture specific code
327 #include <asm/arch/time.h>