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
);
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
);
57 /* change this if you have some constant time drift */
58 #define USECS_PER_JIFFY (1000000/HZ)
61 unsigned long profile_pc(struct pt_regs
*regs
)
63 unsigned long fp
, pc
= instruction_pointer(regs
);
65 if (in_lock_functions(pc
)) {
67 pc
= pc_pointer(((unsigned long *)fp
)[-1]);
72 EXPORT_SYMBOL(profile_pc
);
76 * hook for setting the RTC's idea of the current time.
80 static unsigned long dummy_gettimeoffset(void)
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
103 static inline void do_set_rtc(void)
105 if (time_status
& STA_UNSYNC
|| set_rtc
== NULL
)
108 if (next_rtc_update
&&
109 time_before((unsigned long)xtime
.tv_sec
, next_rtc_update
))
112 if (xtime
.tv_nsec
< 500000000 - ((unsigned) tick_nsec
>> 1) &&
113 xtime
.tv_nsec
>= 500000000 + ((unsigned) tick_nsec
>> 1))
118 * rtc update failed. Try again in 60s
120 next_rtc_update
= xtime
.tv_sec
+ 60;
122 next_rtc_update
= xtime
.tv_sec
+ 660;
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
{
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')
153 if (strncmp(buf
, "claim", len
) == 0) {
154 leds_event(led_claim
);
156 } else if (strncmp(buf
, "release", len
) == 0) {
157 leds_event(led_release
);
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)
166 if (strncmp(buf
+len
, " on", 3) == 0) {
167 leds_event(evt_names
[i
].on
);
169 } else if (strncmp(buf
+len
, " off", 4) == 0) {
170 leds_event(evt_names
[i
].off
);
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
);
187 static int leds_resume(struct sys_device
*dev
)
189 leds_event(led_start
);
193 static int leds_shutdown(struct sys_device
*dev
)
195 leds_event(led_halted
);
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
= {
208 .cls
= &leds_sysclass
,
211 static int __init
leds_init(void)
214 ret
= sysdev_class_register(&leds_sysclass
);
216 ret
= sysdev_register(&leds_device
);
218 ret
= sysdev_create_file(&leds_device
, &attr_event
);
222 device_initcall(leds_init
);
224 EXPORT_SYMBOL(leds_event
);
227 #ifdef CONFIG_LEDS_TIMER
228 static inline void do_leds(void)
230 static unsigned int count
= 50;
234 leds_event(led_timer
);
241 void do_gettimeofday(struct timeval
*tv
)
245 unsigned long usec
, sec
, lost
;
248 seq
= read_seqbegin_irqsave(&xtime_lock
, flags
);
249 usec
= system_timer
->offset();
251 lost
= jiffies
- wall_jiffies
;
253 usec
+= lost
* USECS_PER_JIFFY
;
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) {
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
)
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
);
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
)
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
);
349 update_process_times(user_mode(regs
));
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
)
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
)
374 #define timer_suspend NULL
375 #define timer_resume NULL
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
;
392 write_seqlock_irqsave(&xtime_lock
, flags
);
394 if (!(dyn_tick
->state
& DYN_TICK_ENABLED
)) {
395 ret
= dyn_tick
->enable();
398 dyn_tick
->state
|= DYN_TICK_ENABLED
;
400 write_sequnlock_irqrestore(&xtime_lock
, flags
);
406 static int timer_dyn_tick_disable(void)
408 struct dyn_tick_timer
*dyn_tick
= system_timer
->dyn_tick
;
413 write_seqlock_irqsave(&xtime_lock
, flags
);
415 if (dyn_tick
->state
& DYN_TICK_ENABLED
) {
416 ret
= dyn_tick
->disable();
419 dyn_tick
->state
&= ~DYN_TICK_ENABLED
;
421 write_sequnlock_irqrestore(&xtime_lock
, flags
);
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
,
451 unsigned int enable
= simple_strtoul(buf
, NULL
, 2);
454 timer_dyn_tick_enable();
456 timer_dyn_tick_disable();
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
)
470 strlcpy(dyntick_str
, str
, sizeof(dyntick_str
));
474 __setup("dyntick=", dyntick_setup
);
477 static int __init
timer_init_sysfs(void)
479 int ret
= sysdev_class_register(&timer_sysclass
);
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();
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();