[mirror_ubuntu-zesty-kernel.git] / arch / arm / kernel / time.c

/*
 *  linux/arch/arm/kernel/time.c
 *
 *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
 *  Modifications for ARM (C) 1994-2001 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  This file contains the ARM-specific time handling details:
 *  reading the RTC at bootup, etc...
 *
 *  1994-07-02  Alan Modra
 *              fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
 *  1998-12-20  Updated NTP code according to technical memorandum Jan '96
 *              "A Kernel Model for Precision Timekeeping" by Dave Mills
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/timex.h>
#include <linux/errno.h>
#include <linux/profile.h>
#include <linux/sysdev.h>
#include <linux/timer.h>
#include <linux/irq.h>

#include <linux/mc146818rtc.h>

#include <asm/leds.h>
#include <asm/thread_info.h>
#include <asm/mach/time.h>

/*
 * Our system timer.
 */
struct sys_timer *system_timer;

/* this needs a better home */
DEFINE_SPINLOCK(rtc_lock);

#ifdef CONFIG_SA1100_RTC_MODULE
EXPORT_SYMBOL(rtc_lock);
#endif

/* change this if you have some constant time drift */
#define USECS_PER_JIFFY	(1000000/HZ)

#ifdef CONFIG_SMP
unsigned long profile_pc(struct pt_regs *regs)
{
	unsigned long fp, pc = instruction_pointer(regs);

	if (in_lock_functions(pc)) {
		fp = regs->ARM_fp;
		pc = pc_pointer(((unsigned long *)fp)[-1]);
	}

	return pc;
}
EXPORT_SYMBOL(profile_pc);
#endif

/*
 * hook for setting the RTC's idea of the current time.
 */
int (*set_rtc)(void);

#ifndef CONFIG_GENERIC_TIME
static unsigned long dummy_gettimeoffset(void)
{
	return 0;
}
#endif

/*
 * Scheduler clock - returns current time in nanosec units.
 * This is the default implementation.  Sub-architecture
 * implementations can override this.
 */
unsigned long long __attribute__((weak)) sched_clock(void)
{
	return (unsigned long long)jiffies * (1000000000 / HZ);
}

static unsigned long next_rtc_update;

/*
 * If we have an externally synchronized linux clock, then update
 * CMOS clock accordingly every ~11 minutes.  set_rtc() has to be
 * called as close as possible to 500 ms before the new second
 * starts.
 */
static inline void do_set_rtc(void)
{
	if (!ntp_synced() || set_rtc == NULL)
		return;

	if (next_rtc_update &&
	    time_before((unsigned long)xtime.tv_sec, next_rtc_update))
		return;

	if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
	    xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
		return;

	if (set_rtc())
		/*
		 * rtc update failed.  Try again in 60s
		 */
		next_rtc_update = xtime.tv_sec + 60;
	else
		next_rtc_update = xtime.tv_sec + 660;
}

#ifdef CONFIG_LEDS

static void dummy_leds_event(led_event_t evt)
{
}

void (*leds_event)(led_event_t) = dummy_leds_event;

struct leds_evt_name {
	const char	name[8];
	int		on;
	int		off;
};

static const struct leds_evt_name evt_names[] = {
	{ "amber", led_amber_on, led_amber_off },
	{ "blue",  led_blue_on,  led_blue_off  },
	{ "green", led_green_on, led_green_off },
	{ "red",   led_red_on,   led_red_off   },
};

static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
{
	int ret = -EINVAL, len = strcspn(buf, " ");

	if (len > 0 && buf[len] == '\0')
		len--;

	if (strncmp(buf, "claim", len) == 0) {
		leds_event(led_claim);
		ret = size;
	} else if (strncmp(buf, "release", len) == 0) {
		leds_event(led_release);
		ret = size;
	} else {
		int i;

		for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
			if (strlen(evt_names[i].name) != len ||
			    strncmp(buf, evt_names[i].name, len) != 0)
				continue;
			if (strncmp(buf+len, " on", 3) == 0) {
				leds_event(evt_names[i].on);
				ret = size;
			} else if (strncmp(buf+len, " off", 4) == 0) {
				leds_event(evt_names[i].off);
				ret = size;
			}
			break;
		}
	}
	return ret;
}

static SYSDEV_ATTR(event, 0200, NULL, leds_store);

static int leds_suspend(struct sys_device *dev, pm_message_t state)
{
	leds_event(led_stop);
	return 0;
}

static int leds_resume(struct sys_device *dev)
{
	leds_event(led_start);
	return 0;
}

static int leds_shutdown(struct sys_device *dev)
{
	leds_event(led_halted);
	return 0;
}

static struct sysdev_class leds_sysclass = {
	set_kset_name("leds"),
	.shutdown	= leds_shutdown,
	.suspend	= leds_suspend,
	.resume		= leds_resume,
};

static struct sys_device leds_device = {
	.id		= 0,
	.cls		= &leds_sysclass,
};

static int __init leds_init(void)
{
	int ret;
	ret = sysdev_class_register(&leds_sysclass);
	if (ret == 0)
		ret = sysdev_register(&leds_device);
	if (ret == 0)
		ret = sysdev_create_file(&leds_device, &attr_event);
	return ret;
}

device_initcall(leds_init);

EXPORT_SYMBOL(leds_event);
#endif

#ifdef CONFIG_LEDS_TIMER
static inline void do_leds(void)
{
	static unsigned int count = HZ/2;

	if (--count == 0) {
		count = HZ/2;
		leds_event(led_timer);
	}
}
#else
#define	do_leds()
#endif

#ifndef CONFIG_GENERIC_TIME
void do_gettimeofday(struct timeval *tv)
{
	unsigned long flags;
	unsigned long seq;
	unsigned long usec, sec;

	do {
		seq = read_seqbegin_irqsave(&xtime_lock, flags);
		usec = system_timer->offset();
		sec = xtime.tv_sec;
		usec += xtime.tv_nsec / 1000;
	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));

	/* usec may have gone up a lot: be safe */
	while (usec >= 1000000) {
		usec -= 1000000;
		sec++;
	}

	tv->tv_sec = sec;
	tv->tv_usec = usec;
}

EXPORT_SYMBOL(do_gettimeofday);

int do_settimeofday(struct timespec *tv)
{
	time_t wtm_sec, sec = tv->tv_sec;
	long wtm_nsec, nsec = tv->tv_nsec;

	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
		return -EINVAL;

	write_seqlock_irq(&xtime_lock);
	/*
	 * This is revolting. We need to set "xtime" correctly. However, the
	 * value in this location is the value at the most recent update of
	 * wall time.  Discover what correction gettimeofday() would have
	 * done, and then undo it!
	 */
	nsec -= system_timer->offset() * NSEC_PER_USEC;

	wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);

	set_normalized_timespec(&xtime, sec, nsec);
	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);

	ntp_clear();
	write_sequnlock_irq(&xtime_lock);
	clock_was_set();
	return 0;
}

EXPORT_SYMBOL(do_settimeofday);
#endif /* !CONFIG_GENERIC_TIME */

/**
 * save_time_delta - Save the offset between system time and RTC time
 * @delta: pointer to timespec to store delta
 * @rtc: pointer to timespec for current RTC time
 *
 * Return a delta between the system time and the RTC time, such
 * that system time can be restored later with restore_time_delta()
 */
void save_time_delta(struct timespec *delta, struct timespec *rtc)
{
	set_normalized_timespec(delta,
				xtime.tv_sec - rtc->tv_sec,
				xtime.tv_nsec - rtc->tv_nsec);
}
EXPORT_SYMBOL(save_time_delta);

/**
 * restore_time_delta - Restore the current system time
 * @delta: delta returned by save_time_delta()
 * @rtc: pointer to timespec for current RTC time
 */
void restore_time_delta(struct timespec *delta, struct timespec *rtc)
{
	struct timespec ts;

	set_normalized_timespec(&ts,
				delta->tv_sec + rtc->tv_sec,
				delta->tv_nsec + rtc->tv_nsec);

	do_settimeofday(&ts);
}
EXPORT_SYMBOL(restore_time_delta);

/*
 * Kernel system timer support.
 */
void timer_tick(void)
{
	profile_tick(CPU_PROFILING);
	do_leds();
	do_set_rtc();
	do_timer(1);
#ifndef CONFIG_SMP
	update_process_times(user_mode(get_irq_regs()));
#endif
}

#ifdef CONFIG_PM
static int timer_suspend(struct sys_device *dev, pm_message_t state)
{
	struct sys_timer *timer = container_of(dev, struct sys_timer, dev);

	if (timer->suspend != NULL)
		timer->suspend();

	return 0;
}

static int timer_resume(struct sys_device *dev)
{
	struct sys_timer *timer = container_of(dev, struct sys_timer, dev);

	if (timer->resume != NULL)
		timer->resume();

	return 0;
}
#else
#define timer_suspend NULL
#define timer_resume NULL
#endif

static struct sysdev_class timer_sysclass = {
	set_kset_name("timer"),
	.suspend	= timer_suspend,
	.resume		= timer_resume,
};

#ifdef CONFIG_NO_IDLE_HZ
static int timer_dyn_tick_enable(void)
{
	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
	unsigned long flags;
	int ret = -ENODEV;

	if (dyn_tick) {
		spin_lock_irqsave(&dyn_tick->lock, flags);
		ret = 0;
		if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
			ret = dyn_tick->enable();

			if (ret == 0)
				dyn_tick->state |= DYN_TICK_ENABLED;
		}
		spin_unlock_irqrestore(&dyn_tick->lock, flags);
	}

	return ret;
}

static int timer_dyn_tick_disable(void)
{
	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
	unsigned long flags;
	int ret = -ENODEV;

	if (dyn_tick) {
		spin_lock_irqsave(&dyn_tick->lock, flags);
		ret = 0;
		if (dyn_tick->state & DYN_TICK_ENABLED) {
			ret = dyn_tick->disable();

			if (ret == 0)
				dyn_tick->state &= ~DYN_TICK_ENABLED;
		}
		spin_unlock_irqrestore(&dyn_tick->lock, flags);
	}

	return ret;
}

/*
 * Reprogram the system timer for at least the calculated time interval.
 * This function should be called from the idle thread with IRQs disabled,
 * immediately before sleeping.
 */
void timer_dyn_reprogram(void)
{
	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
	unsigned long next, seq, flags;

	if (!dyn_tick)
		return;

	spin_lock_irqsave(&dyn_tick->lock, flags);
	if (dyn_tick->state & DYN_TICK_ENABLED) {
		next = next_timer_interrupt();
		do {
			seq = read_seqbegin(&xtime_lock);
			dyn_tick->reprogram(next - jiffies);
		} while (read_seqretry(&xtime_lock, seq));
	}
	spin_unlock_irqrestore(&dyn_tick->lock, flags);
}

static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
{
	return sprintf(buf, "%i\n",
		       (system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
}

static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,
				  size_t count)
{
	unsigned int enable = simple_strtoul(buf, NULL, 2);

	if (enable)
		timer_dyn_tick_enable();
	else
		timer_dyn_tick_disable();

	return count;
}
static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);

/*
 * dyntick=enable|disable
 */
static char dyntick_str[4] __initdata = "";

static int __init dyntick_setup(char *str)
{
	if (str)
		strlcpy(dyntick_str, str, sizeof(dyntick_str));
	return 1;
}

__setup("dyntick=", dyntick_setup);
#endif

static int __init timer_init_sysfs(void)
{
	int ret = sysdev_class_register(&timer_sysclass);
	if (ret == 0) {
		system_timer->dev.cls = &timer_sysclass;
		ret = sysdev_register(&system_timer->dev);
	}

#ifdef CONFIG_NO_IDLE_HZ
	if (ret == 0 && system_timer->dyn_tick) {
		ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick);

		/*
		 * Turn on dynamic tick after calibrate delay
		 * for correct bogomips
		 */
		if (ret == 0 && dyntick_str[0] == 'e')
			ret = timer_dyn_tick_enable();
	}
#endif

	return ret;
}

device_initcall(timer_init_sysfs);

void __init time_init(void)
{
#ifndef CONFIG_GENERIC_TIME
	if (system_timer->offset == NULL)
		system_timer->offset = dummy_gettimeoffset;
#endif
	system_timer->init();

#ifdef CONFIG_NO_IDLE_HZ
	if (system_timer->dyn_tick)
		system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED;
#endif
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/arch/arm/kernel/time.c
	3	*
	4	* Copyright (C) 1991, 1992, 1995 Linus Torvalds
	5	* Modifications for ARM (C) 1994-2001 Russell King
	6	*
	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.
	10	*
	11	* This file contains the ARM-specific time handling details:
	12	* reading the RTC at bootup, etc...
	13	*
	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
	18	*/
1da177e4 LT	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>
e317c8cc	30	#include <linux/irq.h>
1da177e4	31
9ca3f07b BD	32	#include <linux/mc146818rtc.h>
9ca3f07b BD	33
1da177e4 LT	34	#include <asm/leds.h>
	35	#include <asm/thread_info.h>
	36	#include <asm/mach/time.h>
	37
1da177e4 LT	38	/*
	39	* Our system timer.
	40	*/
	41	struct sys_timer *system_timer;
	42
1da177e4 LT	43	/* this needs a better home */
	44	DEFINE_SPINLOCK(rtc_lock);
	45
	46	#ifdef CONFIG_SA1100_RTC_MODULE
	47	EXPORT_SYMBOL(rtc_lock);
	48	#endif
	49
	50	/* change this if you have some constant time drift */
	51	#define USECS_PER_JIFFY (1000000/HZ)
	52
	53	#ifdef CONFIG_SMP
	54	unsigned long profile_pc(struct pt_regs *regs)
	55	{
	56	unsigned long fp, pc = instruction_pointer(regs);
	57
	58	if (in_lock_functions(pc)) {
	59	fp = regs->ARM_fp;
	60	pc = pc_pointer(((unsigned long *)fp)[-1]);
	61	}
	62
	63	return pc;
	64	}
	65	EXPORT_SYMBOL(profile_pc);
	66	#endif
	67
	68	/*
	69	* hook for setting the RTC's idea of the current time.
	70	*/
	71	int (*set_rtc)(void);
	72
746140c7	73	#ifndef CONFIG_GENERIC_TIME
1da177e4 LT	74	static unsigned long dummy_gettimeoffset(void)
	75	{
	76	return 0;
	77	}
746140c7	78	#endif
1da177e4 LT	79
	80	/*
	81	* Scheduler clock - returns current time in nanosec units.
	82	* This is the default implementation. Sub-architecture
	83	* implementations can override this.
	84	*/
	85	unsigned long long __attribute__((weak)) sched_clock(void)
	86	{
	87	return (unsigned long long)jiffies * (1000000000 / HZ);
	88	}
	89
	90	static unsigned long next_rtc_update;
	91
	92	/*
	93	* If we have an externally synchronized linux clock, then update
	94	* CMOS clock accordingly every ~11 minutes. set_rtc() has to be
	95	* called as close as possible to 500 ms before the new second
	96	* starts.
	97	*/
	98	static inline void do_set_rtc(void)
	99	{
b149ee22	100	if (!ntp_synced() \|\| set_rtc == NULL)
1da177e4 LT	101	return;
	102
	103	if (next_rtc_update &&
	104	time_before((unsigned long)xtime.tv_sec, next_rtc_update))
	105	return;
	106
	107	if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
	108	xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
	109	return;
	110
	111	if (set_rtc())
	112	/*
	113	* rtc update failed. Try again in 60s
	114	*/
	115	next_rtc_update = xtime.tv_sec + 60;
	116	else
	117	next_rtc_update = xtime.tv_sec + 660;
	118	}
	119
	120	#ifdef CONFIG_LEDS
	121
	122	static void dummy_leds_event(led_event_t evt)
	123	{
	124	}
	125
	126	void (*leds_event)(led_event_t) = dummy_leds_event;
	127
	128	struct leds_evt_name {
	129	const char name[8];
	130	int on;
	131	int off;
	132	};
	133
	134	static const struct leds_evt_name evt_names[] = {
	135	{ "amber", led_amber_on, led_amber_off },
	136	{ "blue", led_blue_on, led_blue_off },
	137	{ "green", led_green_on, led_green_off },
	138	{ "red", led_red_on, led_red_off },
	139	};
	140
	141	static ssize_t leds_store(struct sys_device dev, const char buf, size_t size)
	142	{
	143	int ret = -EINVAL, len = strcspn(buf, " ");
	144
	145	if (len > 0 && buf[len] == '\0')
	146	len--;
	147
	148	if (strncmp(buf, "claim", len) == 0) {
	149	leds_event(led_claim);
	150	ret = size;
	151	} else if (strncmp(buf, "release", len) == 0) {
	152	leds_event(led_release);
	153	ret = size;
	154	} else {
	155	int i;
	156
	157	for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
	158	if (strlen(evt_names[i].name) != len \|\|
	159	strncmp(buf, evt_names[i].name, len) != 0)
	160	continue;
	161	if (strncmp(buf+len, " on", 3) == 0) {
	162	leds_event(evt_names[i].on);
	163	ret = size;
	164	} else if (strncmp(buf+len, " off", 4) == 0) {
165	leds_event(evt_names[i].off);
166	ret = size;
167	}
168	break;
169	}
170	}
171	return ret;
172	}
173
174	static SYSDEV_ATTR(event, 0200, NULL, leds_store);
175
176	static int leds_suspend(struct sys_device *dev, pm_message_t state)
177	{
178	leds_event(led_stop);
179	return 0;
180	}
181
182	static int leds_resume(struct sys_device *dev)
183	{
184	leds_event(led_start);
185	return 0;
186	}
187
188	static int leds_shutdown(struct sys_device *dev)
189	{
190	leds_event(led_halted);
191	return 0;
192	}
193
194	static struct sysdev_class leds_sysclass = {
195	set_kset_name("leds"),
196	.shutdown = leds_shutdown,
197	.suspend = leds_suspend,
198	.resume = leds_resume,
199	};
200
201	static struct sys_device leds_device = {
202	.id = 0,
203	.cls = &leds_sysclass,
204	};
205
206	static int __init leds_init(void)
207	{
208	int ret;
209	ret = sysdev_class_register(&leds_sysclass);
210	if (ret == 0)
211	ret = sysdev_register(&leds_device);
212	if (ret == 0)
213	ret = sysdev_create_file(&leds_device, &attr_event);
214	return ret;
215	}
216
217	device_initcall(leds_init);
218
219	EXPORT_SYMBOL(leds_event);
220	#endif
221
222	#ifdef CONFIG_LEDS_TIMER
223	static inline void do_leds(void)
224	{
6d15cb42	225	static unsigned int count = HZ/2;
1da177e4 LT	226
1da177e4 LT	227	if (--count == 0) {
6d15cb42	228	count = HZ/2;
1da177e4 LT	229	leds_event(led_timer);
	230	}
	231	}
	232	#else
	233	#define do_leds()
	234	#endif
	235
746140c7	236	#ifndef CONFIG_GENERIC_TIME
1da177e4 LT	237	void do_gettimeofday(struct timeval *tv)
	238	{
	239	unsigned long flags;
	240	unsigned long seq;
8ef38609	241	unsigned long usec, sec;
1da177e4 LT	242
	243	do {
	244	seq = read_seqbegin_irqsave(&xtime_lock, flags);
	245	usec = system_timer->offset();
1da177e4 LT	246	sec = xtime.tv_sec;
	247	usec += xtime.tv_nsec / 1000;
	248	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
	249
	250	/* usec may have gone up a lot: be safe */
	251	while (usec >= 1000000) {
	252	usec -= 1000000;
	253	sec++;
	254	}
	255
	256	tv->tv_sec = sec;
	257	tv->tv_usec = usec;
	258	}
	259
	260	EXPORT_SYMBOL(do_gettimeofday);
	261
	262	int do_settimeofday(struct timespec *tv)
	263	{
	264	time_t wtm_sec, sec = tv->tv_sec;
	265	long wtm_nsec, nsec = tv->tv_nsec;
	266
	267	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
	268	return -EINVAL;
	269
	270	write_seqlock_irq(&xtime_lock);
	271	/*
	272	* This is revolting. We need to set "xtime" correctly. However, the
	273	* value in this location is the value at the most recent update of
	274	* wall time. Discover what correction gettimeofday() would have
	275	* done, and then undo it!
	276	*/
	277	nsec -= system_timer->offset() * NSEC_PER_USEC;
1da177e4 LT	278
	279	wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
	280	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
	281
	282	set_normalized_timespec(&xtime, sec, nsec);
	283	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
	284
b149ee22	285	ntp_clear();
1da177e4 LT	286	write_sequnlock_irq(&xtime_lock);
	287	clock_was_set();
	288	return 0;
	289	}
	290
	291	EXPORT_SYMBOL(do_settimeofday);
746140c7	292	#endif /* !CONFIG_GENERIC_TIME */
1da177e4 LT	293
	294	/**
	295	* save_time_delta - Save the offset between system time and RTC time
	296	* @delta: pointer to timespec to store delta
	297	* @rtc: pointer to timespec for current RTC time
	298	*
	299	* Return a delta between the system time and the RTC time, such
	300	* that system time can be restored later with restore_time_delta()
	301	*/
	302	void save_time_delta(struct timespec delta, struct timespec rtc)
	303	{
	304	set_normalized_timespec(delta,
	305	xtime.tv_sec - rtc->tv_sec,
	306	xtime.tv_nsec - rtc->tv_nsec);
	307	}
	308	EXPORT_SYMBOL(save_time_delta);
	309
	310	/**
	311	* restore_time_delta - Restore the current system time
	312	* @delta: delta returned by save_time_delta()
	313	* @rtc: pointer to timespec for current RTC time
	314	*/
	315	void restore_time_delta(struct timespec delta, struct timespec rtc)
	316	{
	317	struct timespec ts;
	318
	319	set_normalized_timespec(&ts,
	320	delta->tv_sec + rtc->tv_sec,
	321	delta->tv_nsec + rtc->tv_nsec);
	322
	323	do_settimeofday(&ts);
	324	}
	325	EXPORT_SYMBOL(restore_time_delta);
	326
	327	/*
	328	* Kernel system timer support.
	329	*/
0cd61b68	330	void timer_tick(void)
1da177e4	331	{
e317c8cc	332	profile_tick(CPU_PROFILING);
1da177e4 LT	333	do_leds();
1da177e4 LT	334	do_set_rtc();
3171a030	335	do_timer(1);
1da177e4	336	#ifndef CONFIG_SMP
c97d4869	337	update_process_times(user_mode(get_irq_regs()));
1da177e4 LT	338	#endif
	339	}
	340
	341	#ifdef CONFIG_PM
	342	static int timer_suspend(struct sys_device *dev, pm_message_t state)
	343	{
	344	struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
	345
	346	if (timer->suspend != NULL)
	347	timer->suspend();
	348
	349	return 0;
	350	}
	351
	352	static int timer_resume(struct sys_device *dev)
	353	{
	354	struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
	355
	356	if (timer->resume != NULL)
	357	timer->resume();
	358
	359	return 0;
	360	}
	361	#else
	362	#define timer_suspend NULL
	363	#define timer_resume NULL
	364	#endif
	365
	366	static struct sysdev_class timer_sysclass = {
	367	set_kset_name("timer"),
	368	.suspend = timer_suspend,
	369	.resume = timer_resume,
	370	};
	371
8749af68 RK	372	#ifdef CONFIG_NO_IDLE_HZ
	373	static int timer_dyn_tick_enable(void)
	374	{
	375	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
	376	unsigned long flags;
	377	int ret = -ENODEV;
	378
	379	if (dyn_tick) {
ebc67da6	380	spin_lock_irqsave(&dyn_tick->lock, flags);
8749af68 RK	381	ret = 0;
	382	if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
	383	ret = dyn_tick->enable();
	384
	385	if (ret == 0)
	386	dyn_tick->state \|= DYN_TICK_ENABLED;
	387	}
ebc67da6	388	spin_unlock_irqrestore(&dyn_tick->lock, flags);
8749af68 RK	389	}
	390
	391	return ret;
	392	}
	393
	394	static int timer_dyn_tick_disable(void)
	395	{
	396	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
	397	unsigned long flags;
	398	int ret = -ENODEV;
	399
	400	if (dyn_tick) {
ebc67da6	401	spin_lock_irqsave(&dyn_tick->lock, flags);
8749af68 RK	402	ret = 0;
	403	if (dyn_tick->state & DYN_TICK_ENABLED) {
	404	ret = dyn_tick->disable();
	405
	406	if (ret == 0)
	407	dyn_tick->state &= ~DYN_TICK_ENABLED;
	408	}
ebc67da6	409	spin_unlock_irqrestore(&dyn_tick->lock, flags);
8749af68 RK	410	}
	411
	412	return ret;
	413	}
	414
2ea83398 RK	415	/*
	416	* Reprogram the system timer for at least the calculated time interval.
	417	* This function should be called from the idle thread with IRQs disabled,
	418	* immediately before sleeping.
	419	*/
8749af68 RK	420	void timer_dyn_reprogram(void)
	421	{
	422	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
ebc67da6	423	unsigned long next, seq, flags;
8749af68	424
ebc67da6 TL	425	if (!dyn_tick)
	426	return;
	427
	428	spin_lock_irqsave(&dyn_tick->lock, flags);
	429	if (dyn_tick->state & DYN_TICK_ENABLED) {
69239749 TL	430	next = next_timer_interrupt();
	431	do {
	432	seq = read_seqbegin(&xtime_lock);
ebc67da6	433	dyn_tick->reprogram(next - jiffies);
69239749	434	} while (read_seqretry(&xtime_lock, seq));
3618886f	435	}
ebc67da6	436	spin_unlock_irqrestore(&dyn_tick->lock, flags);
8749af68 RK	437	}
	438
	439	static ssize_t timer_show_dyn_tick(struct sys_device dev, char buf)
	440	{
	441	return sprintf(buf, "%i\n",
	442	(system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
	443	}
	444
	445	static ssize_t timer_set_dyn_tick(struct sys_device dev, const char buf,
	446	size_t count)
	447	{
	448	unsigned int enable = simple_strtoul(buf, NULL, 2);
	449
	450	if (enable)
	451	timer_dyn_tick_enable();
	452	else
	453	timer_dyn_tick_disable();
	454
	455	return count;
	456	}
	457	static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
	458
	459	/*
	460	* dyntick=enable\|disable
	461	*/
	462	static char dyntick_str[4] __initdata = "";
	463
	464	static int __init dyntick_setup(char *str)
	465	{
	466	if (str)
	467	strlcpy(dyntick_str, str, sizeof(dyntick_str));
	468	return 1;
	469	}
	470
	471	__setup("dyntick=", dyntick_setup);
	472	#endif
	473
1da177e4 LT	474	static int __init timer_init_sysfs(void)
	475	{
	476	int ret = sysdev_class_register(&timer_sysclass);
	477	if (ret == 0) {
	478	system_timer->dev.cls = &timer_sysclass;
	479	ret = sysdev_register(&system_timer->dev);
	480	}
8749af68 RK	481
	482	#ifdef CONFIG_NO_IDLE_HZ
	483	if (ret == 0 && system_timer->dyn_tick) {
	484	ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick);
	485
	486	/*
	487	* Turn on dynamic tick after calibrate delay
	488	* for correct bogomips
	489	*/
	490	if (ret == 0 && dyntick_str[0] == 'e')
	491	ret = timer_dyn_tick_enable();
	492	}
	493	#endif
	494
1da177e4 LT	495	return ret;
	496	}
	497
	498	device_initcall(timer_init_sysfs);
	499
	500	void __init time_init(void)
	501	{
746140c7	502	#ifndef CONFIG_GENERIC_TIME
1da177e4 LT	503	if (system_timer->offset == NULL)
1da177e4 LT	504	system_timer->offset = dummy_gettimeoffset;
746140c7	505	#endif
1da177e4	506	system_timer->init();
ebc67da6 TL	507
	508	#ifdef CONFIG_NO_IDLE_HZ
	509	if (system_timer->dyn_tick)
	510	system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED;
	511	#endif
1da177e4 LT	512	}
1da177e4 LT	513