[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

/*
 * An implementation of printk_clock() independent from
 * sched_clock().  This avoids non-bootable kernels when
 * printk_clock is enabled.
 */
unsigned long long printk_clock(void)
{
	return (unsigned long long)(jiffies - INITIAL_JIFFIES) *
			(1000000000 / HZ);
}

static unsigned long next_rtc_update;

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

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

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

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

#ifdef CONFIG_LEDS

static void dummy_leds_event(led_event_t evt)
{
}

void (*leds_event)(led_event_t) = dummy_leds_event;

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

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

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

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

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

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

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

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

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

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

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

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

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

device_initcall(leds_init);

EXPORT_SYMBOL(leds_event);
#endif

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

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

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

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

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

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

EXPORT_SYMBOL(do_gettimeofday);

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

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

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

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

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

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

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

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

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

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

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

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

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

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

	return 0;
}

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

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

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

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

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

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

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

	return ret;
}

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

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

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

	return ret;
}

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

	if (!dyn_tick)
		return;

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

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

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

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

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

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

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

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

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

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

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

	return ret;
}

device_initcall(timer_init_sysfs);

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

#ifdef CONFIG_NO_IDLE_HZ
	if (system_timer->dyn_tick)
		system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED;
#endif
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/arch/arm/kernel/time.c
	3	*
	4	* Copyright (C) 1991, 1992, 1995 Linus Torvalds
	5	* Modifications for ARM (C) 1994-2001 Russell King
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*
	11	* This file contains the ARM-specific time handling details:
	12	* reading the RTC at bootup, etc...
	13	*
	14	* 1994-07-02 Alan Modra
	15	* fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
	16	* 1998-12-20 Updated NTP code according to technical memorandum Jan '96
	17	* "A Kernel Model for Precision Timekeeping" by Dave Mills
	18	*/
1da177e4 LT	19	#include <linux/module.h>
	20	#include <linux/kernel.h>
	21	#include <linux/interrupt.h>
	22	#include <linux/time.h>
	23	#include <linux/init.h>
	24	#include <linux/smp.h>
	25	#include <linux/timex.h>
	26	#include <linux/errno.h>
	27	#include <linux/profile.h>
	28	#include <linux/sysdev.h>
	29	#include <linux/timer.h>
e317c8cc	30	#include <linux/irq.h>
1da177e4	31
9ca3f07b BD	32	#include <linux/mc146818rtc.h>
9ca3f07b BD	33
1da177e4 LT	34	#include <asm/leds.h>
	35	#include <asm/thread_info.h>
	36	#include <asm/mach/time.h>
	37
1da177e4 LT	38	/*
	39	* Our system timer.
	40	*/
	41	struct sys_timer *system_timer;
	42
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
e97126cd RK	82	/*
	83	* An implementation of printk_clock() independent from
	84	* sched_clock(). This avoids non-bootable kernels when
	85	* printk_clock is enabled.
	86	*/
	87	unsigned long long printk_clock(void)
	88	{
	89	return (unsigned long long)(jiffies - INITIAL_JIFFIES) *
	90	(1000000000 / HZ);
	91	}
	92
1da177e4 LT	93	static unsigned long next_rtc_update;
	94
	95	/*
	96	* If we have an externally synchronized linux clock, then update
	97	* CMOS clock accordingly every ~11 minutes. set_rtc() has to be
	98	* called as close as possible to 500 ms before the new second
	99	* starts.
	100	*/
	101	static inline void do_set_rtc(void)
	102	{
b149ee22	103	if (!ntp_synced() \|\| set_rtc == NULL)
1da177e4 LT	104	return;
	105
	106	if (next_rtc_update &&
	107	time_before((unsigned long)xtime.tv_sec, next_rtc_update))
	108	return;
	109
	110	if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) &&
	111	xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1))
	112	return;
	113
	114	if (set_rtc())
	115	/*
	116	* rtc update failed. Try again in 60s
	117	*/
	118	next_rtc_update = xtime.tv_sec + 60;
	119	else
	120	next_rtc_update = xtime.tv_sec + 660;
	121	}
	122
	123	#ifdef CONFIG_LEDS
	124
	125	static void dummy_leds_event(led_event_t evt)
	126	{
	127	}
	128
	129	void (*leds_event)(led_event_t) = dummy_leds_event;
	130
	131	struct leds_evt_name {
	132	const char name[8];
	133	int on;
	134	int off;
	135	};
	136
	137	static const struct leds_evt_name evt_names[] = {
	138	{ "amber", led_amber_on, led_amber_off },
	139	{ "blue", led_blue_on, led_blue_off },
	140	{ "green", led_green_on, led_green_off },
	141	{ "red", led_red_on, led_red_off },
	142	};
	143
	144	static ssize_t leds_store(struct sys_device dev, const char buf, size_t size)
	145	{
	146	int ret = -EINVAL, len = strcspn(buf, " ");
	147
	148	if (len > 0 && buf[len] == '\0')
	149	len--;
	150
	151	if (strncmp(buf, "claim", len) == 0) {
	152	leds_event(led_claim);
	153	ret = size;
	154	} else if (strncmp(buf, "release", len) == 0) {
	155	leds_event(led_release);
	156	ret = size;
	157	} else {
	158	int i;
	159
	160	for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
	161	if (strlen(evt_names[i].name) != len \|\|
	162	strncmp(buf, evt_names[i].name, len) != 0)
	163	continue;
	164	if (strncmp(buf+len, " on", 3) == 0) {
	165	leds_event(evt_names[i].on);
	166	ret = size;
	167	} else if (strncmp(buf+len, " off", 4) == 0) {
168	leds_event(evt_names[i].off);
169	ret = size;
170	}
171	break;
172	}
173	}
174	return ret;
175	}
176
177	static SYSDEV_ATTR(event, 0200, NULL, leds_store);
178
179	static int leds_suspend(struct sys_device *dev, pm_message_t state)
180	{
181	leds_event(led_stop);
182	return 0;
183	}
184
185	static int leds_resume(struct sys_device *dev)
186	{
187	leds_event(led_start);
188	return 0;
189	}
190
191	static int leds_shutdown(struct sys_device *dev)
192	{
193	leds_event(led_halted);
194	return 0;
195	}
196
197	static struct sysdev_class leds_sysclass = {
198	set_kset_name("leds"),
199	.shutdown = leds_shutdown,
200	.suspend = leds_suspend,
201	.resume = leds_resume,
202	};
203
204	static struct sys_device leds_device = {
205	.id = 0,
206	.cls = &leds_sysclass,
207	};
208
209	static int __init leds_init(void)
210	{
211	int ret;
212	ret = sysdev_class_register(&leds_sysclass);
213	if (ret == 0)
214	ret = sysdev_register(&leds_device);
215	if (ret == 0)
216	ret = sysdev_create_file(&leds_device, &attr_event);
217	return ret;
218	}
219
220	device_initcall(leds_init);
221
222	EXPORT_SYMBOL(leds_event);
223	#endif
224
225	#ifdef CONFIG_LEDS_TIMER
226	static inline void do_leds(void)
227	{
6d15cb42	228	static unsigned int count = HZ/2;
1da177e4 LT	229
1da177e4 LT	230	if (--count == 0) {
6d15cb42	231	count = HZ/2;
1da177e4 LT	232	leds_event(led_timer);
	233	}
	234	}
	235	#else
	236	#define do_leds()
	237	#endif
	238
746140c7	239	#ifndef CONFIG_GENERIC_TIME
1da177e4 LT	240	void do_gettimeofday(struct timeval *tv)
	241	{
	242	unsigned long flags;
	243	unsigned long seq;
8ef38609	244	unsigned long usec, sec;
1da177e4 LT	245
	246	do {
	247	seq = read_seqbegin_irqsave(&xtime_lock, flags);
	248	usec = system_timer->offset();
1da177e4 LT	249	sec = xtime.tv_sec;
	250	usec += xtime.tv_nsec / 1000;
	251	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
	252
	253	/* usec may have gone up a lot: be safe */
	254	while (usec >= 1000000) {
	255	usec -= 1000000;
	256	sec++;
	257	}
	258
	259	tv->tv_sec = sec;
	260	tv->tv_usec = usec;
	261	}
	262
	263	EXPORT_SYMBOL(do_gettimeofday);
	264
	265	int do_settimeofday(struct timespec *tv)
	266	{
	267	time_t wtm_sec, sec = tv->tv_sec;
	268	long wtm_nsec, nsec = tv->tv_nsec;
	269
	270	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
	271	return -EINVAL;
	272
	273	write_seqlock_irq(&xtime_lock);
	274	/*
	275	* This is revolting. We need to set "xtime" correctly. However, the
	276	* value in this location is the value at the most recent update of
	277	* wall time. Discover what correction gettimeofday() would have
	278	* done, and then undo it!
	279	*/
	280	nsec -= system_timer->offset() * NSEC_PER_USEC;
1da177e4 LT	281
	282	wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
	283	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
	284
	285	set_normalized_timespec(&xtime, sec, nsec);
	286	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
	287
b149ee22	288	ntp_clear();
1da177e4 LT	289	write_sequnlock_irq(&xtime_lock);
	290	clock_was_set();
	291	return 0;
	292	}
	293
	294	EXPORT_SYMBOL(do_settimeofday);
746140c7	295	#endif /* !CONFIG_GENERIC_TIME */
1da177e4 LT	296
	297	/**
	298	* save_time_delta - Save the offset between system time and RTC time
	299	* @delta: pointer to timespec to store delta
	300	* @rtc: pointer to timespec for current RTC time
	301	*
	302	* Return a delta between the system time and the RTC time, such
	303	* that system time can be restored later with restore_time_delta()
	304	*/
	305	void save_time_delta(struct timespec delta, struct timespec rtc)
	306	{
	307	set_normalized_timespec(delta,
	308	xtime.tv_sec - rtc->tv_sec,
	309	xtime.tv_nsec - rtc->tv_nsec);
	310	}
	311	EXPORT_SYMBOL(save_time_delta);
	312
	313	/**
	314	* restore_time_delta - Restore the current system time
	315	* @delta: delta returned by save_time_delta()
	316	* @rtc: pointer to timespec for current RTC time
	317	*/
	318	void restore_time_delta(struct timespec delta, struct timespec rtc)
	319	{
	320	struct timespec ts;
	321
	322	set_normalized_timespec(&ts,
	323	delta->tv_sec + rtc->tv_sec,
	324	delta->tv_nsec + rtc->tv_nsec);
	325
	326	do_settimeofday(&ts);
	327	}
	328	EXPORT_SYMBOL(restore_time_delta);
	329
	330	/*
	331	* Kernel system timer support.
	332	*/
0cd61b68	333	void timer_tick(void)
1da177e4	334	{
e317c8cc	335	profile_tick(CPU_PROFILING);
1da177e4 LT	336	do_leds();
1da177e4 LT	337	do_set_rtc();
3171a030	338	do_timer(1);
1da177e4	339	#ifndef CONFIG_SMP
c97d4869	340	update_process_times(user_mode(get_irq_regs()));
1da177e4 LT	341	#endif
	342	}
	343
	344	#ifdef CONFIG_PM
	345	static int timer_suspend(struct sys_device *dev, pm_message_t state)
	346	{
	347	struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
	348
	349	if (timer->suspend != NULL)
	350	timer->suspend();
	351
	352	return 0;
	353	}
	354
	355	static int timer_resume(struct sys_device *dev)
	356	{
	357	struct sys_timer *timer = container_of(dev, struct sys_timer, dev);
	358
	359	if (timer->resume != NULL)
	360	timer->resume();
	361
	362	return 0;
	363	}
	364	#else
	365	#define timer_suspend NULL
	366	#define timer_resume NULL
	367	#endif
	368
	369	static struct sysdev_class timer_sysclass = {
	370	set_kset_name("timer"),
	371	.suspend = timer_suspend,
	372	.resume = timer_resume,
	373	};
	374
8749af68 RK	375	#ifdef CONFIG_NO_IDLE_HZ
	376	static int timer_dyn_tick_enable(void)
	377	{
	378	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
	379	unsigned long flags;
	380	int ret = -ENODEV;
	381
	382	if (dyn_tick) {
ebc67da6	383	spin_lock_irqsave(&dyn_tick->lock, flags);
8749af68 RK	384	ret = 0;
	385	if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
	386	ret = dyn_tick->enable();
	387
	388	if (ret == 0)
	389	dyn_tick->state \|= DYN_TICK_ENABLED;
	390	}
ebc67da6	391	spin_unlock_irqrestore(&dyn_tick->lock, flags);
8749af68 RK	392	}
	393
	394	return ret;
	395	}
	396
	397	static int timer_dyn_tick_disable(void)
	398	{
	399	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
	400	unsigned long flags;
	401	int ret = -ENODEV;
	402
	403	if (dyn_tick) {
ebc67da6	404	spin_lock_irqsave(&dyn_tick->lock, flags);
8749af68 RK	405	ret = 0;
	406	if (dyn_tick->state & DYN_TICK_ENABLED) {
	407	ret = dyn_tick->disable();
	408
	409	if (ret == 0)
	410	dyn_tick->state &= ~DYN_TICK_ENABLED;
	411	}
ebc67da6	412	spin_unlock_irqrestore(&dyn_tick->lock, flags);
8749af68 RK	413	}
	414
	415	return ret;
	416	}
	417
2ea83398 RK	418	/*
	419	* Reprogram the system timer for at least the calculated time interval.
	420	* This function should be called from the idle thread with IRQs disabled,
	421	* immediately before sleeping.
	422	*/
8749af68 RK	423	void timer_dyn_reprogram(void)
	424	{
	425	struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
ebc67da6	426	unsigned long next, seq, flags;
8749af68	427
ebc67da6 TL	428	if (!dyn_tick)
	429	return;
	430
	431	spin_lock_irqsave(&dyn_tick->lock, flags);
	432	if (dyn_tick->state & DYN_TICK_ENABLED) {
69239749 TL	433	next = next_timer_interrupt();
	434	do {
	435	seq = read_seqbegin(&xtime_lock);
ebc67da6	436	dyn_tick->reprogram(next - jiffies);
69239749	437	} while (read_seqretry(&xtime_lock, seq));
3618886f	438	}
ebc67da6	439	spin_unlock_irqrestore(&dyn_tick->lock, flags);
8749af68 RK	440	}
	441
	442	static ssize_t timer_show_dyn_tick(struct sys_device dev, char buf)
	443	{
	444	return sprintf(buf, "%i\n",
	445	(system_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
	446	}
	447
	448	static ssize_t timer_set_dyn_tick(struct sys_device dev, const char buf,
	449	size_t count)
	450	{
	451	unsigned int enable = simple_strtoul(buf, NULL, 2);
	452
	453	if (enable)
	454	timer_dyn_tick_enable();
	455	else
	456	timer_dyn_tick_disable();
	457
	458	return count;
	459	}
	460	static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
	461
	462	/*
	463	* dyntick=enable\|disable
	464	*/
	465	static char dyntick_str[4] __initdata = "";
	466
	467	static int __init dyntick_setup(char *str)
	468	{
	469	if (str)
	470	strlcpy(dyntick_str, str, sizeof(dyntick_str));
	471	return 1;
	472	}
	473
	474	__setup("dyntick=", dyntick_setup);
	475	#endif
	476
1da177e4 LT	477	static int __init timer_init_sysfs(void)
	478	{
	479	int ret = sysdev_class_register(&timer_sysclass);
	480	if (ret == 0) {
	481	system_timer->dev.cls = &timer_sysclass;
	482	ret = sysdev_register(&system_timer->dev);
	483	}
8749af68 RK	484
	485	#ifdef CONFIG_NO_IDLE_HZ
	486	if (ret == 0 && system_timer->dyn_tick) {
	487	ret = sysdev_create_file(&system_timer->dev, &attr_dyn_tick);
	488
	489	/*
	490	* Turn on dynamic tick after calibrate delay
	491	* for correct bogomips
	492	*/
	493	if (ret == 0 && dyntick_str[0] == 'e')
	494	ret = timer_dyn_tick_enable();
	495	}
	496	#endif
	497
1da177e4 LT	498	return ret;
	499	}
	500
	501	device_initcall(timer_init_sysfs);
	502
	503	void __init time_init(void)
	504	{
746140c7	505	#ifndef CONFIG_GENERIC_TIME
1da177e4 LT	506	if (system_timer->offset == NULL)
1da177e4 LT	507	system_timer->offset = dummy_gettimeoffset;
746140c7	508	#endif
1da177e4	509	system_timer->init();
ebc67da6 TL	510
	511	#ifdef CONFIG_NO_IDLE_HZ
	512	if (system_timer->dyn_tick)
	513	system_timer->dyn_tick->lock = SPIN_LOCK_UNLOCKED;
	514	#endif
1da177e4 LT	515	}
1da177e4 LT	516