[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 <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;

#if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE)
/* this needs a better home */
DEFINE_SPINLOCK(rtc_lock);

#ifdef CONFIG_RTC_DRV_CMOS_MODULE
EXPORT_SYMBOL(rtc_lock);
#endif
#endif	/* pc-style 'CMOS' RTC support */

/* 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

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 = {
	.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);

#ifndef CONFIG_GENERIC_CLOCKEVENTS
/*
 * 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
}
#endif

#if defined(CONFIG_PM) && !defined(CONFIG_GENERIC_CLOCKEVENTS)
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 = {
	.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)
		spin_lock_init(&system_timer->dyn_tick->lock);
#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
9dd34948	43	#if defined(CONFIG_RTC_DRV_CMOS) \|\| defined(CONFIG_RTC_DRV_CMOS_MODULE)
1da177e4 LT	44	/* this needs a better home */
	45	DEFINE_SPINLOCK(rtc_lock);
	46
9dd34948	47	#ifdef CONFIG_RTC_DRV_CMOS_MODULE
1da177e4 LT	48	EXPORT_SYMBOL(rtc_lock);
1da177e4 LT	49	#endif
9dd34948	50	#endif /* pc-style 'CMOS' RTC support */
1da177e4 LT	51
	52	/* change this if you have some constant time drift */
	53	#define USECS_PER_JIFFY (1000000/HZ)
	54
	55	#ifdef CONFIG_SMP
	56	unsigned long profile_pc(struct pt_regs *regs)
	57	{
	58	unsigned long fp, pc = instruction_pointer(regs);
	59
	60	if (in_lock_functions(pc)) {
	61	fp = regs->ARM_fp;
	62	pc = pc_pointer(((unsigned long *)fp)[-1]);
	63	}
	64
	65	return pc;
	66	}
	67	EXPORT_SYMBOL(profile_pc);
	68	#endif
	69
	70	/*
	71	* hook for setting the RTC's idea of the current time.
	72	*/
	73	int (*set_rtc)(void);
	74
746140c7	75	#ifndef CONFIG_GENERIC_TIME
1da177e4 LT	76	static unsigned long dummy_gettimeoffset(void)
	77	{
	78	return 0;
	79	}
746140c7	80	#endif
1da177e4	81
1da177e4 LT	82	static unsigned long next_rtc_update;
	83
	84	/*
	85	* If we have an externally synchronized linux clock, then update
	86	* CMOS clock accordingly every ~11 minutes. set_rtc() has to be
	87	* called as close as possible to 500 ms before the new second
	88	* starts.
	89	*/
	90	static inline void do_set_rtc(void)
	91	{
b149ee22	92	if (!ntp_synced() \|\| set_rtc == NULL)
1da177e4 LT	93	return;
	94
	95	if (next_rtc_update &&
	96	time_before((unsigned long)xtime.tv_sec, next_rtc_update))
	97	return;
	98
	99	if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
	100	xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
	101	return;
	102
	103	if (set_rtc())
	104	/*
	105	* rtc update failed. Try again in 60s
	106	*/
	107	next_rtc_update = xtime.tv_sec + 60;
	108	else
	109	next_rtc_update = xtime.tv_sec + 660;
	110	}
	111
	112	#ifdef CONFIG_LEDS
	113
	114	static void dummy_leds_event(led_event_t evt)
	115	{
	116	}
	117
	118	void (*leds_event)(led_event_t) = dummy_leds_event;
	119
	120	struct leds_evt_name {
	121	const char name[8];
	122	int on;
	123	int off;
	124	};
	125
	126	static const struct leds_evt_name evt_names[] = {
	127	{ "amber", led_amber_on, led_amber_off },
	128	{ "blue", led_blue_on, led_blue_off },
	129	{ "green", led_green_on, led_green_off },
	130	{ "red", led_red_on, led_red_off },
	131	};
	132
	133	static ssize_t leds_store(struct sys_device dev, const char buf, size_t size)
	134	{
	135	int ret = -EINVAL, len = strcspn(buf, " ");
	136
	137	if (len > 0 && buf[len] == '\0')
	138	len--;
	139
	140	if (strncmp(buf, "claim", len) == 0) {
	141	leds_event(led_claim);
	142	ret = size;
	143	} else if (strncmp(buf, "release", len) == 0) {
	144	leds_event(led_release);
	145	ret = size;
	146	} else {
	147	int i;
	148
	149	for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
	150	if (strlen(evt_names[i].name) != len \|\|
	151	strncmp(buf, evt_names[i].name, len) != 0)
	152	continue;
	153	if (strncmp(buf+len, " on", 3) == 0) {
	154	leds_event(evt_names[i].on);
	155	ret = size;
	156	} else if (strncmp(buf+len, " off", 4) == 0) {
157	leds_event(evt_names[i].off);
158	ret = size;
159	}
160	break;
161	}
162	}
163	return ret;
164	}
165
166	static SYSDEV_ATTR(event, 0200, NULL, leds_store);
167
168	static int leds_suspend(struct sys_device *dev, pm_message_t state)
169	{
170	leds_event(led_stop);
171	return 0;
172	}
173
174	static int leds_resume(struct sys_device *dev)
175	{
176	leds_event(led_start);
177	return 0;
178	}
179
180	static int leds_shutdown(struct sys_device *dev)
181	{
182	leds_event(led_halted);
183	return 0;
184	}
185
186	static struct sysdev_class leds_sysclass = {
af5ca3f4	187	.name = "leds",
1da177e4 LT	188	.shutdown = leds_shutdown,
	189	.suspend = leds_suspend,
	190	.resume = leds_resume,
	191	};
	192
	193	static struct sys_device leds_device = {
	194	.id = 0,
	195	.cls = &leds_sysclass,
	196	};
	197
	198	static int __init leds_init(void)
	199	{
	200	int ret;
	201	ret = sysdev_class_register(&leds_sysclass);
	202	if (ret == 0)
	203	ret = sysdev_register(&leds_device);
	204	if (ret == 0)
	205	ret = sysdev_create_file(&leds_device, &attr_event);
	206	return ret;
	207	}
	208
	209	device_initcall(leds_init);
	210
	211	EXPORT_SYMBOL(leds_event);
	212	#endif
	213
	214	#ifdef CONFIG_LEDS_TIMER
	215	static inline void do_leds(void)
	216	{
6d15cb42	217	static unsigned int count = HZ/2;
1da177e4 LT	218
1da177e4 LT	219	if (--count == 0) {
6d15cb42	220	count = HZ/2;
1da177e4 LT	221	leds_event(led_timer);
	222	}
	223	}
	224	#else
	225	#define do_leds()
	226	#endif
	227
746140c7	228	#ifndef CONFIG_GENERIC_TIME
1da177e4 LT	229	void do_gettimeofday(struct timeval *tv)
	230	{
	231	unsigned long flags;
	232	unsigned long seq;
8ef38609	233	unsigned long usec, sec;
1da177e4 LT	234
	235	do {
	236	seq = read_seqbegin_irqsave(&xtime_lock, flags);
	237	usec = system_timer->offset();
1da177e4 LT	238	sec = xtime.tv_sec;
	239	usec += xtime.tv_nsec / 1000;
	240	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
	241
	242	/* usec may have gone up a lot: be safe */
	243	while (usec >= 1000000) {
	244	usec -= 1000000;
	245	sec++;
	246	}
	247
	248	tv->tv_sec = sec;
	249	tv->tv_usec = usec;
	250	}
	251
	252	EXPORT_SYMBOL(do_gettimeofday);
	253
	254	int do_settimeofday(struct timespec *tv)
	255	{
	256	time_t wtm_sec, sec = tv->tv_sec;
	257	long wtm_nsec, nsec = tv->tv_nsec;
	258
	259	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
	260	return -EINVAL;
	261
	262	write_seqlock_irq(&xtime_lock);
	263	/*
	264	* This is revolting. We need to set "xtime" correctly. However, the
	265	* value in this location is the value at the most recent update of
	266	* wall time. Discover what correction gettimeofday() would have
	267	* done, and then undo it!
	268	*/
	269	nsec -= system_timer->offset() * NSEC_PER_USEC;
1da177e4 LT	270
	271	wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
	272	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
	273
	274	set_normalized_timespec(&xtime, sec, nsec);
	275	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
	276
b149ee22	277	ntp_clear();
1da177e4 LT	278	write_sequnlock_irq(&xtime_lock);
	279	clock_was_set();
	280	return 0;
	281	}
	282
	283	EXPORT_SYMBOL(do_settimeofday);
746140c7	284	#endif /* !CONFIG_GENERIC_TIME */
1da177e4 LT	285
	286	/**
	287	* save_time_delta - Save the offset between system time and RTC time
	288	* @delta: pointer to timespec to store delta
	289	* @rtc: pointer to timespec for current RTC time
	290	*
	291	* Return a delta between the system time and the RTC time, such
	292	* that system time can be restored later with restore_time_delta()
	293	*/
	294	void save_time_delta(struct timespec delta, struct timespec rtc)
	295	{
	296	set_normalized_timespec(delta,
	297	xtime.tv_sec - rtc->tv_sec,
	298	xtime.tv_nsec - rtc->tv_nsec);
	299	}
	300	EXPORT_SYMBOL(save_time_delta);
	301
	302	/**
	303	* restore_time_delta - Restore the current system time
	304	* @delta: delta returned by save_time_delta()
	305	* @rtc: pointer to timespec for current RTC time
	306	*/
	307	void restore_time_delta(struct timespec delta, struct timespec rtc)
	308	{
	309	struct timespec ts;
	310
	311	set_normalized_timespec(&ts,
	312	delta->tv_sec + rtc->tv_sec,
	313	delta->tv_nsec + rtc->tv_nsec);
	314
	315	do_settimeofday(&ts);
	316	}
	317	EXPORT_SYMBOL(restore_time_delta);
	318
9e4559dd	319	#ifndef CONFIG_GENERIC_CLOCKEVENTS
1da177e4 LT	320	/*
	321	* Kernel system timer support.
	322	*/
0cd61b68	323	void timer_tick(void)
1da177e4	324	{
e317c8cc	325	profile_tick(CPU_PROFILING);
1da177e4 LT	326	do_leds();
1da177e4 LT	327	do_set_rtc();
3171a030	328	do_timer(1);
1da177e4	329	#ifndef CONFIG_SMP
c97d4869	330	update_process_times(user_mode(get_irq_regs()));
1da177e4 LT	331	#endif
1da177e4 LT	332	}
9e4559dd	333	#endif
1da177e4	334
9e4559dd	335	#if defined(CONFIG_PM) && !defined(CONFIG_GENERIC_CLOCKEVENTS)
1da177e4 LT	336	static int timer_suspend(struct sys_device *dev, pm_message_t state)
	337	{
	338	struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
	339
	340	if (timer->suspend != NULL)
	341	timer->suspend();
	342
	343	return 0;
	344	}
	345
	346	static int timer_resume(struct sys_device *dev)
	347	{
	348	struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
	349
	350	if (timer->resume != NULL)
	351	timer->resume();
	352
	353	return 0;
	354	}
	355	#else
	356	#define timer_suspend NULL
	357	#define timer_resume NULL
	358	#endif
	359
	360	static struct sysdev_class timer_sysclass = {
af5ca3f4	361	.name = "timer",
1da177e4 LT	362	.suspend = timer_suspend,
	363	.resume = timer_resume,
	364	};
	365
8749af68 RK	366	#ifdef CONFIG_NO_IDLE_HZ
	367	static int timer_dyn_tick_enable(void)
	368	{
	369	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
	370	unsigned long flags;
	371	int ret = -ENODEV;
	372
	373	if (dyn_tick) {
ebc67da6	374	spin_lock_irqsave(&dyn_tick->lock, flags);
8749af68 RK	375	ret = 0;
	376	if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
	377	ret = dyn_tick->enable();
	378
	379	if (ret == 0)
	380	dyn_tick->state \|= DYN_TICK_ENABLED;
	381	}
ebc67da6	382	spin_unlock_irqrestore(&dyn_tick->lock, flags);
8749af68 RK	383	}
	384
	385	return ret;
	386	}
	387
	388	static int timer_dyn_tick_disable(void)
	389	{
	390	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
	391	unsigned long flags;
	392	int ret = -ENODEV;
	393
	394	if (dyn_tick) {
ebc67da6	395	spin_lock_irqsave(&dyn_tick->lock, flags);
8749af68 RK	396	ret = 0;
	397	if (dyn_tick->state & DYN_TICK_ENABLED) {
	398	ret = dyn_tick->disable();
	399
	400	if (ret == 0)
	401	dyn_tick->state &= ~DYN_TICK_ENABLED;
	402	}
ebc67da6	403	spin_unlock_irqrestore(&dyn_tick->lock, flags);
8749af68 RK	404	}
	405
	406	return ret;
	407	}
	408
2ea83398 RK	409	/*
	410	* Reprogram the system timer for at least the calculated time interval.
	411	* This function should be called from the idle thread with IRQs disabled,
	412	* immediately before sleeping.
	413	*/
8749af68 RK	414	void timer_dyn_reprogram(void)
	415	{
	416	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
ebc67da6	417	unsigned long next, seq, flags;
8749af68	418
ebc67da6 TL	419	if (!dyn_tick)
	420	return;
	421
	422	spin_lock_irqsave(&dyn_tick->lock, flags);
	423	if (dyn_tick->state & DYN_TICK_ENABLED) {
69239749 TL	424	next = next_timer_interrupt();
	425	do {
	426	seq = read_seqbegin(&xtime_lock);
ebc67da6	427	dyn_tick->reprogram(next - jiffies);
69239749	428	} while (read_seqretry(&xtime_lock, seq));
3618886f	429	}
ebc67da6	430	spin_unlock_irqrestore(&dyn_tick->lock, flags);
8749af68 RK	431	}
	432
	433	static ssize_t timer_show_dyn_tick(struct sys_device dev, char buf)
	434	{
	435	return sprintf(buf, "%i\n",
	436	(system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
	437	}
	438
	439	static ssize_t timer_set_dyn_tick(struct sys_device dev, const char buf,
	440	size_t count)
	441	{
	442	unsigned int enable = simple_strtoul(buf, NULL, 2);
	443
	444	if (enable)
	445	timer_dyn_tick_enable();
	446	else
	447	timer_dyn_tick_disable();
	448
	449	return count;
	450	}
	451	static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
	452
	453	/*
	454	* dyntick=enable\|disable
	455	*/
	456	static char dyntick_str[4] __initdata = "";
	457
	458	static int __init dyntick_setup(char *str)
	459	{
	460	if (str)
	461	strlcpy(dyntick_str, str, sizeof(dyntick_str));
	462	return 1;
	463	}
	464
	465	__setup("dyntick=", dyntick_setup);
	466	#endif
	467
1da177e4 LT	468	static int __init timer_init_sysfs(void)
	469	{
	470	int ret = sysdev_class_register(&timer_sysclass);
	471	if (ret == 0) {
	472	system_timer->dev.cls = &timer_sysclass;
	473	ret = sysdev_register(&system_timer->dev);
	474	}
8749af68 RK	475
	476	#ifdef CONFIG_NO_IDLE_HZ
	477	if (ret == 0 && system_timer->dyn_tick) {
	478	ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick);
	479
	480	/*
	481	* Turn on dynamic tick after calibrate delay
	482	* for correct bogomips
	483	*/
	484	if (ret == 0 && dyntick_str[0] == 'e')
	485	ret = timer_dyn_tick_enable();
	486	}
	487	#endif
	488
1da177e4 LT	489	return ret;
	490	}
	491
	492	device_initcall(timer_init_sysfs);
	493
	494	void __init time_init(void)
	495	{
746140c7	496	#ifndef CONFIG_GENERIC_TIME
1da177e4 LT	497	if (system_timer->offset == NULL)
1da177e4 LT	498	system_timer->offset = dummy_gettimeoffset;
746140c7	499	#endif
1da177e4	500	system_timer->init();
ebc67da6 TL	501
	502	#ifdef CONFIG_NO_IDLE_HZ
	503	if (system_timer->dyn_tick)
87b247c4	504	spin_lock_init(&system_timer->dyn_tick->lock);
ebc67da6	505	#endif
1da177e4 LT	506	}
1da177e4 LT	507