[deliverable/linux.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 <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 = 50;

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