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

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

extern unsigned long wall_jiffies;

/* 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, lost;

	do {
		seq = read_seqbegin_irqsave(&xtime_lock, flags);
		usec = system_timer->offset();

		lost = jiffies - wall_jiffies;
		if (lost)
			usec += lost * USECS_PER_JIFFY;

		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;
	nsec -= (jiffies - wall_jiffies) * TICK_NSEC;

	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(regs);
#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
	40	extern unsigned long wall_jiffies;
	41
	42	/* this needs a better home */
	43	DEFINE_SPINLOCK(rtc_lock);
	44
	45	#ifdef CONFIG_SA1100_RTC_MODULE
	46	EXPORT_SYMBOL(rtc_lock);
	47	#endif
	48
	49	/* change this if you have some constant time drift */
	50	#define USECS_PER_JIFFY (1000000/HZ)
	51
	52	#ifdef CONFIG_SMP
	53	unsigned long profile_pc(struct pt_regs *regs)
	54	{
	55	unsigned long fp, pc = instruction_pointer(regs);
	56
	57	if (in_lock_functions(pc)) {
	58	fp = regs->ARM_fp;
	59	pc = pc_pointer(((unsigned long *)fp)[-1]);
	60	}
	61
	62	return pc;
	63	}
	64	EXPORT_SYMBOL(profile_pc);
	65	#endif
	66
	67	/*
	68	* hook for setting the RTC's idea of the current time.
	69	*/
	70	int (*set_rtc)(void);
	71
746140c7	72	#ifndef CONFIG_GENERIC_TIME
1da177e4 LT	73	static unsigned long dummy_gettimeoffset(void)
	74	{
	75	return 0;
	76	}
746140c7	77	#endif
1da177e4 LT	78
	79	/*
	80	* Scheduler clock - returns current time in nanosec units.
	81	* This is the default implementation. Sub-architecture
	82	* implementations can override this.
	83	*/
	84	unsigned long long __attribute__((weak)) sched_clock(void)
	85	{
	86	return (unsigned long long)jiffies * (1000000000 / HZ);
	87	}
	88
	89	static unsigned long next_rtc_update;
	90
	91	/*
	92	* If we have an externally synchronized linux clock, then update
	93	* CMOS clock accordingly every ~11 minutes. set_rtc() has to be
	94	* called as close as possible to 500 ms before the new second
	95	* starts.
	96	*/
	97	static inline void do_set_rtc(void)
	98	{
b149ee22	99	if (!ntp_synced() \|\| set_rtc == NULL)
1da177e4 LT	100	return;
	101
	102	if (next_rtc_update &&
	103	time_before((unsigned long)xtime.tv_sec, next_rtc_update))
	104	return;
	105
	106	if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
	107	xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
	108	return;
	109
	110	if (set_rtc())
	111	/*
	112	* rtc update failed. Try again in 60s
	113	*/
	114	next_rtc_update = xtime.tv_sec + 60;
	115	else
	116	next_rtc_update = xtime.tv_sec + 660;
	117	}
	118
	119	#ifdef CONFIG_LEDS
	120
	121	static void dummy_leds_event(led_event_t evt)
	122	{
	123	}
	124
	125	void (*leds_event)(led_event_t) = dummy_leds_event;
	126
	127	struct leds_evt_name {
	128	const char name[8];
	129	int on;
	130	int off;
	131	};
	132
	133	static const struct leds_evt_name evt_names[] = {
	134	{ "amber", led_amber_on, led_amber_off },
	135	{ "blue", led_blue_on, led_blue_off },
	136	{ "green", led_green_on, led_green_off },
	137	{ "red", led_red_on, led_red_off },
	138	};
	139
	140	static ssize_t leds_store(struct sys_device dev, const char buf, size_t size)
	141	{
	142	int ret = -EINVAL, len = strcspn(buf, " ");
	143
	144	if (len > 0 && buf[len] == '\0')
	145	len--;
	146
	147	if (strncmp(buf, "claim", len) == 0) {
	148	leds_event(led_claim);
	149	ret = size;
	150	} else if (strncmp(buf, "release", len) == 0) {
	151	leds_event(led_release);
	152	ret = size;
	153	} else {
	154	int i;
	155
	156	for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
	157	if (strlen(evt_names[i].name) != len \|\|
	158	strncmp(buf, evt_names[i].name, len) != 0)
	159	continue;
	160	if (strncmp(buf+len, " on", 3) == 0) {
	161	leds_event(evt_names[i].on);
	162	ret = size;
	163	} else if (strncmp(buf+len, " off", 4) == 0) {
164	leds_event(evt_names[i].off);
165	ret = size;
166	}
167	break;
168	}
169	}
170	return ret;
171	}
172
173	static SYSDEV_ATTR(event, 0200, NULL, leds_store);
174
175	static int leds_suspend(struct sys_device *dev, pm_message_t state)
176	{
177	leds_event(led_stop);
178	return 0;
179	}
180
181	static int leds_resume(struct sys_device *dev)
182	{
183	leds_event(led_start);
184	return 0;
185	}
186
187	static int leds_shutdown(struct sys_device *dev)
188	{
189	leds_event(led_halted);
190	return 0;
191	}
192
193	static struct sysdev_class leds_sysclass = {
194	set_kset_name("leds"),
195	.shutdown = leds_shutdown,
196	.suspend = leds_suspend,
197	.resume = leds_resume,
198	};
199
200	static struct sys_device leds_device = {
201	.id = 0,
202	.cls = &leds_sysclass,
203	};
204
205	static int __init leds_init(void)
206	{
207	int ret;
208	ret = sysdev_class_register(&leds_sysclass);
209	if (ret == 0)
210	ret = sysdev_register(&leds_device);
211	if (ret == 0)
212	ret = sysdev_create_file(&leds_device, &attr_event);
213	return ret;
214	}
215
216	device_initcall(leds_init);
217
218	EXPORT_SYMBOL(leds_event);
219	#endif
220
221	#ifdef CONFIG_LEDS_TIMER
222	static inline void do_leds(void)
223	{
224	static unsigned int count = 50;
225
226	if (--count == 0) {
227	count = 50;
228	leds_event(led_timer);
229	}
230	}
231	#else
232	#define do_leds()
233	#endif
234
746140c7	235	#ifndef CONFIG_GENERIC_TIME
1da177e4 LT	236	void do_gettimeofday(struct timeval *tv)
	237	{
	238	unsigned long flags;
	239	unsigned long seq;
	240	unsigned long usec, sec, lost;
	241
	242	do {
	243	seq = read_seqbegin_irqsave(&xtime_lock, flags);
	244	usec = system_timer->offset();
	245
	246	lost = jiffies - wall_jiffies;
	247	if (lost)
	248	usec += lost * USECS_PER_JIFFY;
	249
	250	sec = xtime.tv_sec;
	251	usec += xtime.tv_nsec / 1000;
	252	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
	253
	254	/* usec may have gone up a lot: be safe */
	255	while (usec >= 1000000) {
	256	usec -= 1000000;
	257	sec++;
	258	}
	259
	260	tv->tv_sec = sec;
	261	tv->tv_usec = usec;
	262	}
	263
	264	EXPORT_SYMBOL(do_gettimeofday);
	265
	266	int do_settimeofday(struct timespec *tv)
	267	{
	268	time_t wtm_sec, sec = tv->tv_sec;
	269	long wtm_nsec, nsec = tv->tv_nsec;
	270
	271	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
	272	return -EINVAL;
	273
	274	write_seqlock_irq(&xtime_lock);
	275	/*
	276	* This is revolting. We need to set "xtime" correctly. However, the
	277	* value in this location is the value at the most recent update of
	278	* wall time. Discover what correction gettimeofday() would have
	279	* done, and then undo it!
	280	*/
	281	nsec -= system_timer->offset() * NSEC_PER_USEC;
	282	nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
	283
	284	wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
	285	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
	286
	287	set_normalized_timespec(&xtime, sec, nsec);
	288	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
	289
b149ee22	290	ntp_clear();
1da177e4 LT	291	write_sequnlock_irq(&xtime_lock);
	292	clock_was_set();
	293	return 0;
	294	}
	295
	296	EXPORT_SYMBOL(do_settimeofday);
746140c7	297	#endif /* !CONFIG_GENERIC_TIME */
1da177e4 LT	298
	299	/**
	300	* save_time_delta - Save the offset between system time and RTC time
	301	* @delta: pointer to timespec to store delta
	302	* @rtc: pointer to timespec for current RTC time
	303	*
	304	* Return a delta between the system time and the RTC time, such
	305	* that system time can be restored later with restore_time_delta()
	306	*/
	307	void save_time_delta(struct timespec delta, struct timespec rtc)
	308	{
	309	set_normalized_timespec(delta,
	310	xtime.tv_sec - rtc->tv_sec,
	311	xtime.tv_nsec - rtc->tv_nsec);
	312	}
	313	EXPORT_SYMBOL(save_time_delta);
	314
	315	/**
	316	* restore_time_delta - Restore the current system time
	317	* @delta: delta returned by save_time_delta()
	318	* @rtc: pointer to timespec for current RTC time
	319	*/
	320	void restore_time_delta(struct timespec delta, struct timespec rtc)
	321	{
	322	struct timespec ts;
	323
	324	set_normalized_timespec(&ts,
	325	delta->tv_sec + rtc->tv_sec,
	326	delta->tv_nsec + rtc->tv_nsec);
	327
	328	do_settimeofday(&ts);
	329	}
	330	EXPORT_SYMBOL(restore_time_delta);
	331
	332	/*
	333	* Kernel system timer support.
	334	*/
	335	void timer_tick(struct pt_regs *regs)
	336	{
	337	profile_tick(CPU_PROFILING, regs);
	338	do_leds();
	339	do_set_rtc();
	340	do_timer(regs);
	341	#ifndef CONFIG_SMP
	342	update_process_times(user_mode(regs));
	343	#endif
	344	}
	345
	346	#ifdef CONFIG_PM
	347	static int timer_suspend(struct sys_device *dev, pm_message_t state)
	348	{
	349	struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
	350
	351	if (timer->suspend != NULL)
	352	timer->suspend();
	353
	354	return 0;
	355	}
	356
	357	static int timer_resume(struct sys_device *dev)
	358	{
	359	struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
	360
	361	if (timer->resume != NULL)
362	timer->resume();
363
364	return 0;
365	}
366	#else
367	#define timer_suspend NULL
368	#define timer_resume NULL
369	#endif
370
371	static struct sysdev_class timer_sysclass = {
372	set_kset_name("timer"),
373	.suspend = timer_suspend,
374	.resume = timer_resume,
375	};
376
8749af68 RK	377	#ifdef CONFIG_NO_IDLE_HZ
	378	static int timer_dyn_tick_enable(void)
	379	{
	380	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
	381	unsigned long flags;
	382	int ret = -ENODEV;
	383
	384	if (dyn_tick) {
ebc67da6	385	spin_lock_irqsave(&dyn_tick->lock, flags);
8749af68 RK	386	ret = 0;
	387	if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
	388	ret = dyn_tick->enable();
	389
	390	if (ret == 0)
	391	dyn_tick->state \|= DYN_TICK_ENABLED;
	392	}
ebc67da6	393	spin_unlock_irqrestore(&dyn_tick->lock, flags);
8749af68 RK	394	}
	395
	396	return ret;
	397	}
	398
	399	static int timer_dyn_tick_disable(void)
	400	{
	401	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
	402	unsigned long flags;
	403	int ret = -ENODEV;
	404
	405	if (dyn_tick) {
ebc67da6	406	spin_lock_irqsave(&dyn_tick->lock, flags);
8749af68 RK	407	ret = 0;
	408	if (dyn_tick->state & DYN_TICK_ENABLED) {
	409	ret = dyn_tick->disable();
	410
	411	if (ret == 0)
	412	dyn_tick->state &= ~DYN_TICK_ENABLED;
	413	}
ebc67da6	414	spin_unlock_irqrestore(&dyn_tick->lock, flags);
8749af68 RK	415	}
	416
	417	return ret;
	418	}
	419
2ea83398 RK	420	/*
	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.
	424	*/
8749af68 RK	425	void timer_dyn_reprogram(void)
	426	{
	427	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
ebc67da6	428	unsigned long next, seq, flags;
8749af68	429
ebc67da6 TL	430	if (!dyn_tick)
	431	return;
	432
	433	spin_lock_irqsave(&dyn_tick->lock, flags);
	434	if (dyn_tick->state & DYN_TICK_ENABLED) {
69239749 TL	435	next = next_timer_interrupt();
	436	do {
	437	seq = read_seqbegin(&xtime_lock);
ebc67da6	438	dyn_tick->reprogram(next - jiffies);
69239749	439	} while (read_seqretry(&xtime_lock, seq));
3618886f	440	}
ebc67da6	441	spin_unlock_irqrestore(&dyn_tick->lock, flags);
8749af68 RK	442	}
	443
	444	static ssize_t timer_show_dyn_tick(struct sys_device dev, char buf)
	445	{
	446	return sprintf(buf, "%i\n",
	447	(system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
	448	}
	449
	450	static ssize_t timer_set_dyn_tick(struct sys_device dev, const char buf,
	451	size_t count)
	452	{
	453	unsigned int enable = simple_strtoul(buf, NULL, 2);
	454
	455	if (enable)
	456	timer_dyn_tick_enable();
	457	else
	458	timer_dyn_tick_disable();
	459
	460	return count;
	461	}
	462	static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
	463
	464	/*
	465	* dyntick=enable\|disable
	466	*/
	467	static char dyntick_str[4] __initdata = "";
	468
	469	static int __init dyntick_setup(char *str)
	470	{
	471	if (str)
	472	strlcpy(dyntick_str, str, sizeof(dyntick_str));
	473	return 1;
	474	}
	475
	476	__setup("dyntick=", dyntick_setup);
	477	#endif
	478
1da177e4 LT	479	static int __init timer_init_sysfs(void)
	480	{
	481	int ret = sysdev_class_register(&timer_sysclass);
	482	if (ret == 0) {
	483	system_timer->dev.cls = &timer_sysclass;
	484	ret = sysdev_register(&system_timer->dev);
	485	}
8749af68 RK	486
	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);
	490
	491	/*
	492	* Turn on dynamic tick after calibrate delay
	493	* for correct bogomips
	494	*/
	495	if (ret == 0 && dyntick_str[0] == 'e')
	496	ret = timer_dyn_tick_enable();
	497	}
	498	#endif
	499
1da177e4 LT	500	return ret;
	501	}
	502
	503	device_initcall(timer_init_sysfs);
	504
	505	void __init time_init(void)
	506	{
746140c7	507	#ifndef CONFIG_GENERIC_TIME
1da177e4 LT	508	if (system_timer->offset == NULL)
1da177e4 LT	509	system_timer->offset = dummy_gettimeoffset;
746140c7	510	#endif
1da177e4	511	system_timer->init();
ebc67da6 TL	512
	513	#ifdef CONFIG_NO_IDLE_HZ
	514	if (system_timer->dyn_tick)
	515	system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED;
	516	#endif
1da177e4 LT	517	}
1da177e4 LT	518