[GitHub/mt8127/android_kernel_alcatel_ttab.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 <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
1da177e4 LT	32	#include <asm/leds.h>
	33	#include <asm/thread_info.h>
	34	#include <asm/mach/time.h>
	35
1da177e4 LT	36	/*
	37	* Our system timer.
	38	*/
	39	struct sys_timer *system_timer;
	40
1da177e4 LT	41	/* this needs a better home */
	42	DEFINE_SPINLOCK(rtc_lock);
	43
	44	#ifdef CONFIG_SA1100_RTC_MODULE
	45	EXPORT_SYMBOL(rtc_lock);
	46	#endif
	47
	48	/* change this if you have some constant time drift */
	49	#define USECS_PER_JIFFY (1000000/HZ)
	50
	51	#ifdef CONFIG_SMP
	52	unsigned long profile_pc(struct pt_regs *regs)
	53	{
	54	unsigned long fp, pc = instruction_pointer(regs);
	55
	56	if (in_lock_functions(pc)) {
	57	fp = regs->ARM_fp;
	58	pc = pc_pointer(((unsigned long *)fp)[-1]);
	59	}
	60
	61	return pc;
	62	}
	63	EXPORT_SYMBOL(profile_pc);
	64	#endif
	65
	66	/*
	67	* hook for setting the RTC's idea of the current time.
	68	*/
	69	int (*set_rtc)(void);
	70
746140c7	71	#ifndef CONFIG_GENERIC_TIME
1da177e4 LT	72	static unsigned long dummy_gettimeoffset(void)
	73	{
	74	return 0;
	75	}
746140c7	76	#endif
1da177e4 LT	77
	78	/*
	79	* Scheduler clock - returns current time in nanosec units.
	80	* This is the default implementation. Sub-architecture
	81	* implementations can override this.
	82	*/
	83	unsigned long long __attribute__((weak)) sched_clock(void)
	84	{
	85	return (unsigned long long)jiffies * (1000000000 / HZ);
	86	}
	87
	88	static unsigned long next_rtc_update;
	89
	90	/*
	91	* If we have an externally synchronized linux clock, then update
	92	* CMOS clock accordingly every ~11 minutes. set_rtc() has to be
	93	* called as close as possible to 500 ms before the new second
	94	* starts.
	95	*/
	96	static inline void do_set_rtc(void)
	97	{
b149ee22	98	if (!ntp_synced() \|\| set_rtc == NULL)
1da177e4 LT	99	return;
	100
	101	if (next_rtc_update &&
	102	time_before((unsigned long)xtime.tv_sec, next_rtc_update))
	103	return;
	104
	105	if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
	106	xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
	107	return;
	108
	109	if (set_rtc())
	110	/*
	111	* rtc update failed. Try again in 60s
	112	*/
	113	next_rtc_update = xtime.tv_sec + 60;
	114	else
	115	next_rtc_update = xtime.tv_sec + 660;
	116	}
	117
	118	#ifdef CONFIG_LEDS
	119
	120	static void dummy_leds_event(led_event_t evt)
	121	{
	122	}
	123
	124	void (*leds_event)(led_event_t) = dummy_leds_event;
	125
	126	struct leds_evt_name {
	127	const char name[8];
	128	int on;
	129	int off;
	130	};
	131
	132	static const struct leds_evt_name evt_names[] = {
	133	{ "amber", led_amber_on, led_amber_off },
	134	{ "blue", led_blue_on, led_blue_off },
	135	{ "green", led_green_on, led_green_off },
	136	{ "red", led_red_on, led_red_off },
	137	};
	138
	139	static ssize_t leds_store(struct sys_device dev, const char buf, size_t size)
	140	{
	141	int ret = -EINVAL, len = strcspn(buf, " ");
	142
	143	if (len > 0 && buf[len] == '\0')
	144	len--;
	145
	146	if (strncmp(buf, "claim", len) == 0) {
	147	leds_event(led_claim);
	148	ret = size;
	149	} else if (strncmp(buf, "release", len) == 0) {
	150	leds_event(led_release);
	151	ret = size;
	152	} else {
	153	int i;
	154
	155	for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
	156	if (strlen(evt_names[i].name) != len \|\|
	157	strncmp(buf, evt_names[i].name, len) != 0)
	158	continue;
	159	if (strncmp(buf+len, " on", 3) == 0) {
	160	leds_event(evt_names[i].on);
	161	ret = size;
	162	} else if (strncmp(buf+len, " off", 4) == 0) {
163	leds_event(evt_names[i].off);
164	ret = size;
165	}
166	break;
167	}
168	}
169	return ret;
170	}
171
172	static SYSDEV_ATTR(event, 0200, NULL, leds_store);
173
174	static int leds_suspend(struct sys_device *dev, pm_message_t state)
175	{
176	leds_event(led_stop);
177	return 0;
178	}
179
180	static int leds_resume(struct sys_device *dev)
181	{
182	leds_event(led_start);
183	return 0;
184	}
185
186	static int leds_shutdown(struct sys_device *dev)
187	{
188	leds_event(led_halted);
189	return 0;
190	}
191
192	static struct sysdev_class leds_sysclass = {
193	set_kset_name("leds"),
194	.shutdown = leds_shutdown,
195	.suspend = leds_suspend,
196	.resume = leds_resume,
197	};
198
199	static struct sys_device leds_device = {
200	.id = 0,
201	.cls = &leds_sysclass,
202	};
203
204	static int __init leds_init(void)
205	{
206	int ret;
207	ret = sysdev_class_register(&leds_sysclass);
208	if (ret == 0)
209	ret = sysdev_register(&leds_device);
210	if (ret == 0)
211	ret = sysdev_create_file(&leds_device, &attr_event);
212	return ret;
213	}
214
215	device_initcall(leds_init);
216
217	EXPORT_SYMBOL(leds_event);
218	#endif
219
220	#ifdef CONFIG_LEDS_TIMER
221	static inline void do_leds(void)
222	{
6d15cb42	223	static unsigned int count = HZ/2;
1da177e4 LT	224
1da177e4 LT	225	if (--count == 0) {
6d15cb42	226	count = HZ/2;
1da177e4 LT	227	leds_event(led_timer);
	228	}
	229	}
	230	#else
	231	#define do_leds()
	232	#endif
	233
746140c7	234	#ifndef CONFIG_GENERIC_TIME
1da177e4 LT	235	void do_gettimeofday(struct timeval *tv)
	236	{
	237	unsigned long flags;
	238	unsigned long seq;
8ef38609	239	unsigned long usec, sec;
1da177e4 LT	240
	241	do {
	242	seq = read_seqbegin_irqsave(&xtime_lock, flags);
	243	usec = system_timer->offset();
1da177e4 LT	244	sec = xtime.tv_sec;
	245	usec += xtime.tv_nsec / 1000;
	246	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
	247
	248	/* usec may have gone up a lot: be safe */
	249	while (usec >= 1000000) {
	250	usec -= 1000000;
	251	sec++;
	252	}
	253
	254	tv->tv_sec = sec;
	255	tv->tv_usec = usec;
	256	}
	257
	258	EXPORT_SYMBOL(do_gettimeofday);
	259
	260	int do_settimeofday(struct timespec *tv)
	261	{
	262	time_t wtm_sec, sec = tv->tv_sec;
	263	long wtm_nsec, nsec = tv->tv_nsec;
	264
	265	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
	266	return -EINVAL;
	267
	268	write_seqlock_irq(&xtime_lock);
	269	/*
	270	* This is revolting. We need to set "xtime" correctly. However, the
	271	* value in this location is the value at the most recent update of
	272	* wall time. Discover what correction gettimeofday() would have
	273	* done, and then undo it!
	274	*/
	275	nsec -= system_timer->offset() * NSEC_PER_USEC;
1da177e4 LT	276
	277	wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
	278	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
	279
	280	set_normalized_timespec(&xtime, sec, nsec);
	281	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
	282
b149ee22	283	ntp_clear();
1da177e4 LT	284	write_sequnlock_irq(&xtime_lock);
	285	clock_was_set();
	286	return 0;
	287	}
	288
	289	EXPORT_SYMBOL(do_settimeofday);
746140c7	290	#endif /* !CONFIG_GENERIC_TIME */
1da177e4 LT	291
	292	/**
	293	* save_time_delta - Save the offset between system time and RTC time
	294	* @delta: pointer to timespec to store delta
	295	* @rtc: pointer to timespec for current RTC time
	296	*
	297	* Return a delta between the system time and the RTC time, such
	298	* that system time can be restored later with restore_time_delta()
	299	*/
	300	void save_time_delta(struct timespec delta, struct timespec rtc)
	301	{
	302	set_normalized_timespec(delta,
	303	xtime.tv_sec - rtc->tv_sec,
	304	xtime.tv_nsec - rtc->tv_nsec);
	305	}
	306	EXPORT_SYMBOL(save_time_delta);
	307
	308	/**
	309	* restore_time_delta - Restore the current system time
	310	* @delta: delta returned by save_time_delta()
	311	* @rtc: pointer to timespec for current RTC time
	312	*/
	313	void restore_time_delta(struct timespec delta, struct timespec rtc)
	314	{
	315	struct timespec ts;
	316
	317	set_normalized_timespec(&ts,
	318	delta->tv_sec + rtc->tv_sec,
	319	delta->tv_nsec + rtc->tv_nsec);
	320
	321	do_settimeofday(&ts);
	322	}
	323	EXPORT_SYMBOL(restore_time_delta);
	324
	325	/*
	326	* Kernel system timer support.
	327	*/
0cd61b68	328	void timer_tick(void)
1da177e4	329	{
e317c8cc	330	profile_tick(CPU_PROFILING);
1da177e4 LT	331	do_leds();
1da177e4 LT	332	do_set_rtc();
3171a030	333	do_timer(1);
1da177e4	334	#ifndef CONFIG_SMP
c97d4869	335	update_process_times(user_mode(get_irq_regs()));
1da177e4 LT	336	#endif
	337	}
	338
	339	#ifdef CONFIG_PM
	340	static int timer_suspend(struct sys_device *dev, pm_message_t state)
	341	{
	342	struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
	343
	344	if (timer->suspend != NULL)
	345	timer->suspend();
	346
	347	return 0;
	348	}
	349
	350	static int timer_resume(struct sys_device *dev)
	351	{
	352	struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
	353
	354	if (timer->resume != NULL)
	355	timer->resume();
	356
	357	return 0;
	358	}
	359	#else
	360	#define timer_suspend NULL
	361	#define timer_resume NULL
	362	#endif
	363
	364	static struct sysdev_class timer_sysclass = {
	365	set_kset_name("timer"),
	366	.suspend = timer_suspend,
	367	.resume = timer_resume,
	368	};
	369
8749af68 RK	370	#ifdef CONFIG_NO_IDLE_HZ
	371	static int timer_dyn_tick_enable(void)
	372	{
	373	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
	374	unsigned long flags;
	375	int ret = -ENODEV;
	376
	377	if (dyn_tick) {
ebc67da6	378	spin_lock_irqsave(&dyn_tick->lock, flags);
8749af68 RK	379	ret = 0;
	380	if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
	381	ret = dyn_tick->enable();
	382
	383	if (ret == 0)
	384	dyn_tick->state \|= DYN_TICK_ENABLED;
	385	}
ebc67da6	386	spin_unlock_irqrestore(&dyn_tick->lock, flags);
8749af68 RK	387	}
	388
	389	return ret;
	390	}
	391
	392	static int timer_dyn_tick_disable(void)
	393	{
	394	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
	395	unsigned long flags;
	396	int ret = -ENODEV;
	397
	398	if (dyn_tick) {
ebc67da6	399	spin_lock_irqsave(&dyn_tick->lock, flags);
8749af68 RK	400	ret = 0;
	401	if (dyn_tick->state & DYN_TICK_ENABLED) {
	402	ret = dyn_tick->disable();
	403
	404	if (ret == 0)
	405	dyn_tick->state &= ~DYN_TICK_ENABLED;
	406	}
ebc67da6	407	spin_unlock_irqrestore(&dyn_tick->lock, flags);
8749af68 RK	408	}
	409
	410	return ret;
	411	}
	412
2ea83398 RK	413	/*
	414	* Reprogram the system timer for at least the calculated time interval.
	415	* This function should be called from the idle thread with IRQs disabled,
	416	* immediately before sleeping.
	417	*/
8749af68 RK	418	void timer_dyn_reprogram(void)
	419	{
	420	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
ebc67da6	421	unsigned long next, seq, flags;
8749af68	422
ebc67da6 TL	423	if (!dyn_tick)
	424	return;
	425
	426	spin_lock_irqsave(&dyn_tick->lock, flags);
	427	if (dyn_tick->state & DYN_TICK_ENABLED) {
69239749 TL	428	next = next_timer_interrupt();
	429	do {
	430	seq = read_seqbegin(&xtime_lock);
ebc67da6	431	dyn_tick->reprogram(next - jiffies);
69239749	432	} while (read_seqretry(&xtime_lock, seq));
3618886f	433	}
ebc67da6	434	spin_unlock_irqrestore(&dyn_tick->lock, flags);
8749af68 RK	435	}
	436
	437	static ssize_t timer_show_dyn_tick(struct sys_device dev, char buf)
	438	{
	439	return sprintf(buf, "%i\n",
	440	(system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
	441	}
	442
	443	static ssize_t timer_set_dyn_tick(struct sys_device dev, const char buf,
	444	size_t count)
	445	{
	446	unsigned int enable = simple_strtoul(buf, NULL, 2);
	447
	448	if (enable)
	449	timer_dyn_tick_enable();
	450	else
	451	timer_dyn_tick_disable();
	452
	453	return count;
	454	}
	455	static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
	456
	457	/*
	458	* dyntick=enable\|disable
	459	*/
	460	static char dyntick_str[4] __initdata = "";
	461
	462	static int __init dyntick_setup(char *str)
	463	{
	464	if (str)
	465	strlcpy(dyntick_str, str, sizeof(dyntick_str));
	466	return 1;
	467	}
	468
	469	__setup("dyntick=", dyntick_setup);
	470	#endif
	471
1da177e4 LT	472	static int __init timer_init_sysfs(void)
	473	{
	474	int ret = sysdev_class_register(&timer_sysclass);
	475	if (ret == 0) {
	476	system_timer->dev.cls = &timer_sysclass;
	477	ret = sysdev_register(&system_timer->dev);
	478	}
8749af68 RK	479
	480	#ifdef CONFIG_NO_IDLE_HZ
	481	if (ret == 0 && system_timer->dyn_tick) {
	482	ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick);
	483
	484	/*
	485	* Turn on dynamic tick after calibrate delay
	486	* for correct bogomips
	487	*/
	488	if (ret == 0 && dyntick_str[0] == 'e')
	489	ret = timer_dyn_tick_enable();
	490	}
	491	#endif
	492
1da177e4 LT	493	return ret;
	494	}
	495
	496	device_initcall(timer_init_sysfs);
	497
	498	void __init time_init(void)
	499	{
746140c7	500	#ifndef CONFIG_GENERIC_TIME
1da177e4 LT	501	if (system_timer->offset == NULL)
1da177e4 LT	502	system_timer->offset = dummy_gettimeoffset;
746140c7	503	#endif
1da177e4	504	system_timer->init();
ebc67da6 TL	505
	506	#ifdef CONFIG_NO_IDLE_HZ
	507	if (system_timer->dyn_tick)
	508	system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED;
	509	#endif
1da177e4 LT	510	}
1da177e4 LT	511