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>
30 #include <linux/irq.h>
32 #include <linux/mc146818rtc.h>
35 #include <asm/thread_info.h>
36 #include <asm/mach/time.h>
41 struct sys_timer
*system_timer
;
43 #if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE)
44 /* this needs a better home */
45 DEFINE_SPINLOCK(rtc_lock
);
47 #ifdef CONFIG_RTC_DRV_CMOS_MODULE
48 EXPORT_SYMBOL(rtc_lock
);
50 #endif /* pc-style 'CMOS' RTC support */
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
)) {
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 #ifndef CONFIG_GENERIC_TIME
76 static unsigned long dummy_gettimeoffset(void)
83 * An implementation of printk_clock() independent from
84 * sched_clock(). This avoids non-bootable kernels when
85 * printk_clock is enabled.
87 unsigned long long printk_clock(void)
89 return (unsigned long long)(jiffies
- INITIAL_JIFFIES
) *
93 static unsigned long next_rtc_update
;
96 * If we have an externally synchronized linux clock, then update
97 * CMOS clock accordingly every ~11 minutes. set_rtc() has to be
98 * called as close as possible to 500 ms before the new second
101 static inline void do_set_rtc(void)
103 if (!ntp_synced() || set_rtc
== NULL
)
106 if (next_rtc_update
&&
107 time_before((unsigned long)xtime
.tv_sec
, next_rtc_update
))
110 if (xtime
.tv_nsec
< 500000000 - ((unsigned) tick_nsec
>> 1) &&
111 xtime
.tv_nsec
>= 500000000 + ((unsigned) tick_nsec
>> 1))
116 * rtc update failed. Try again in 60s
118 next_rtc_update
= xtime
.tv_sec
+ 60;
120 next_rtc_update
= xtime
.tv_sec
+ 660;
125 static void dummy_leds_event(led_event_t evt
)
129 void (*leds_event
)(led_event_t
) = dummy_leds_event
;
131 struct leds_evt_name
{
137 static const struct leds_evt_name evt_names
[] = {
138 { "amber", led_amber_on
, led_amber_off
},
139 { "blue", led_blue_on
, led_blue_off
},
140 { "green", led_green_on
, led_green_off
},
141 { "red", led_red_on
, led_red_off
},
144 static ssize_t
leds_store(struct sys_device
*dev
, const char *buf
, size_t size
)
146 int ret
= -EINVAL
, len
= strcspn(buf
, " ");
148 if (len
> 0 && buf
[len
] == '\0')
151 if (strncmp(buf
, "claim", len
) == 0) {
152 leds_event(led_claim
);
154 } else if (strncmp(buf
, "release", len
) == 0) {
155 leds_event(led_release
);
160 for (i
= 0; i
< ARRAY_SIZE(evt_names
); i
++) {
161 if (strlen(evt_names
[i
].name
) != len
||
162 strncmp(buf
, evt_names
[i
].name
, len
) != 0)
164 if (strncmp(buf
+len
, " on", 3) == 0) {
165 leds_event(evt_names
[i
].on
);
167 } else if (strncmp(buf
+len
, " off", 4) == 0) {
168 leds_event(evt_names
[i
].off
);
177 static SYSDEV_ATTR(event
, 0200, NULL
, leds_store
);
179 static int leds_suspend(struct sys_device
*dev
, pm_message_t state
)
181 leds_event(led_stop
);
185 static int leds_resume(struct sys_device
*dev
)
187 leds_event(led_start
);
191 static int leds_shutdown(struct sys_device
*dev
)
193 leds_event(led_halted
);
197 static struct sysdev_class leds_sysclass
= {
199 .shutdown
= leds_shutdown
,
200 .suspend
= leds_suspend
,
201 .resume
= leds_resume
,
204 static struct sys_device leds_device
= {
206 .cls
= &leds_sysclass
,
209 static int __init
leds_init(void)
212 ret
= sysdev_class_register(&leds_sysclass
);
214 ret
= sysdev_register(&leds_device
);
216 ret
= sysdev_create_file(&leds_device
, &attr_event
);
220 device_initcall(leds_init
);
222 EXPORT_SYMBOL(leds_event
);
225 #ifdef CONFIG_LEDS_TIMER
226 static inline void do_leds(void)
228 static unsigned int count
= HZ
/2;
232 leds_event(led_timer
);
239 #ifndef CONFIG_GENERIC_TIME
240 void do_gettimeofday(struct timeval
*tv
)
244 unsigned long usec
, sec
;
247 seq
= read_seqbegin_irqsave(&xtime_lock
, flags
);
248 usec
= system_timer
->offset();
250 usec
+= xtime
.tv_nsec
/ 1000;
251 } while (read_seqretry_irqrestore(&xtime_lock
, seq
, flags
));
253 /* usec may have gone up a lot: be safe */
254 while (usec
>= 1000000) {
263 EXPORT_SYMBOL(do_gettimeofday
);
265 int do_settimeofday(struct timespec
*tv
)
267 time_t wtm_sec
, sec
= tv
->tv_sec
;
268 long wtm_nsec
, nsec
= tv
->tv_nsec
;
270 if ((unsigned long)tv
->tv_nsec
>= NSEC_PER_SEC
)
273 write_seqlock_irq(&xtime_lock
);
275 * This is revolting. We need to set "xtime" correctly. However, the
276 * value in this location is the value at the most recent update of
277 * wall time. Discover what correction gettimeofday() would have
278 * done, and then undo it!
280 nsec
-= system_timer
->offset() * NSEC_PER_USEC
;
282 wtm_sec
= wall_to_monotonic
.tv_sec
+ (xtime
.tv_sec
- sec
);
283 wtm_nsec
= wall_to_monotonic
.tv_nsec
+ (xtime
.tv_nsec
- nsec
);
285 set_normalized_timespec(&xtime
, sec
, nsec
);
286 set_normalized_timespec(&wall_to_monotonic
, wtm_sec
, wtm_nsec
);
289 write_sequnlock_irq(&xtime_lock
);
294 EXPORT_SYMBOL(do_settimeofday
);
295 #endif /* !CONFIG_GENERIC_TIME */
298 * save_time_delta - Save the offset between system time and RTC time
299 * @delta: pointer to timespec to store delta
300 * @rtc: pointer to timespec for current RTC time
302 * Return a delta between the system time and the RTC time, such
303 * that system time can be restored later with restore_time_delta()
305 void save_time_delta(struct timespec
*delta
, struct timespec
*rtc
)
307 set_normalized_timespec(delta
,
308 xtime
.tv_sec
- rtc
->tv_sec
,
309 xtime
.tv_nsec
- rtc
->tv_nsec
);
311 EXPORT_SYMBOL(save_time_delta
);
314 * restore_time_delta - Restore the current system time
315 * @delta: delta returned by save_time_delta()
316 * @rtc: pointer to timespec for current RTC time
318 void restore_time_delta(struct timespec
*delta
, struct timespec
*rtc
)
322 set_normalized_timespec(&ts
,
323 delta
->tv_sec
+ rtc
->tv_sec
,
324 delta
->tv_nsec
+ rtc
->tv_nsec
);
326 do_settimeofday(&ts
);
328 EXPORT_SYMBOL(restore_time_delta
);
330 #ifndef CONFIG_GENERIC_CLOCKEVENTS
332 * Kernel system timer support.
334 void timer_tick(void)
336 profile_tick(CPU_PROFILING
);
341 update_process_times(user_mode(get_irq_regs()));
346 #if defined(CONFIG_PM) && !defined(CONFIG_GENERIC_CLOCKEVENTS)
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
= {
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 spin_lock_init(&system_timer
->dyn_tick
->lock
);