[deliverable/linux.git] / arch / s390 / kernel / time.c

/*
 *  arch/s390/kernel/time.c
 *    Time of day based timer functions.
 *
 *  S390 version
 *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Hartmut Penner (hp@de.ibm.com),
 *               Martin Schwidefsky (schwidefsky@de.ibm.com),
 *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
 *
 *  Derived from "arch/i386/kernel/time.c"
 *    Copyright (C) 1991, 1992, 1995  Linus Torvalds
 */

#include <linux/errno.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/types.h>
#include <linux/profile.h>
#include <linux/timex.h>
#include <linux/notifier.h>

#include <asm/uaccess.h>
#include <asm/delay.h>
#include <asm/s390_ext.h>
#include <asm/div64.h>
#include <asm/irq.h>
#include <asm/timer.h>

/* change this if you have some constant time drift */
#define USECS_PER_JIFFY     ((unsigned long) 1000000/HZ)
#define CLK_TICKS_PER_JIFFY ((unsigned long) USECS_PER_JIFFY << 12)

/*
 * Create a small time difference between the timer interrupts
 * on the different cpus to avoid lock contention.
 */
#define CPU_DEVIATION       (smp_processor_id() << 12)

#define TICK_SIZE tick

static ext_int_info_t ext_int_info_cc;
static u64 init_timer_cc;
static u64 jiffies_timer_cc;
static u64 xtime_cc;

/*
 * Scheduler clock - returns current time in nanosec units.
 */
unsigned long long sched_clock(void)
{
	return ((get_clock() - jiffies_timer_cc) * 125) >> 9;
}

/*
 * Monotonic_clock - returns # of nanoseconds passed since time_init()
 */
unsigned long long monotonic_clock(void)
{
	return sched_clock();
}
EXPORT_SYMBOL(monotonic_clock);

void tod_to_timeval(__u64 todval, struct timespec *xtime)
{
	unsigned long long sec;

	sec = todval >> 12;
	do_div(sec, 1000000);
	xtime->tv_sec = sec;
	todval -= (sec * 1000000) << 12;
	xtime->tv_nsec = ((todval * 1000) >> 12);
}

static inline unsigned long do_gettimeoffset(void) 
{
	__u64 now;

	now = (get_clock() - jiffies_timer_cc) >> 12;
	now -= (__u64) jiffies * USECS_PER_JIFFY;
	return (unsigned long) now;
}

/*
 * This version of gettimeofday has microsecond resolution.
 */
void do_gettimeofday(struct timeval *tv)
{
	unsigned long flags;
	unsigned long seq;
	unsigned long usec, sec;

	do {
		seq = read_seqbegin_irqsave(&xtime_lock, flags);

		sec = xtime.tv_sec;
		usec = xtime.tv_nsec / 1000 + do_gettimeoffset();
	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));

	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 the xtime.tv_nsec
	 * correctly. However, the value in this location is
	 * is value at the last tick.
	 * Discover what correction gettimeofday
	 * would have done, and then undo it!
	 */
	nsec -= do_gettimeoffset() * 1000;

	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);


#ifdef CONFIG_PROFILING
#define s390_do_profile(regs)	profile_tick(CPU_PROFILING, regs)
#else
#define s390_do_profile(regs)  do { ; } while(0)
#endif /* CONFIG_PROFILING */


/*
 * timer_interrupt() needs to keep up the real-time clock,
 * as well as call the "do_timer()" routine every clocktick
 */
void account_ticks(struct pt_regs *regs)
{
	__u64 tmp;
	__u32 ticks;

	/* Calculate how many ticks have passed. */
	if (S390_lowcore.int_clock < S390_lowcore.jiffy_timer) {
		/*
		 * We have to program the clock comparator even if
		 * no tick has passed. That happens if e.g. an i/o
		 * interrupt wakes up an idle processor that has
		 * switched off its hz timer.
		 */
		tmp = S390_lowcore.jiffy_timer + CPU_DEVIATION;
		asm volatile ("SCKC %0" : : "m" (tmp));
		return;
	}
	tmp = S390_lowcore.int_clock - S390_lowcore.jiffy_timer;
	if (tmp >= 2*CLK_TICKS_PER_JIFFY) {  /* more than two ticks ? */
		ticks = __div(tmp, CLK_TICKS_PER_JIFFY) + 1;
		S390_lowcore.jiffy_timer +=
			CLK_TICKS_PER_JIFFY * (__u64) ticks;
	} else if (tmp >= CLK_TICKS_PER_JIFFY) {
		ticks = 2;
		S390_lowcore.jiffy_timer += 2*CLK_TICKS_PER_JIFFY;
	} else {
		ticks = 1;
		S390_lowcore.jiffy_timer += CLK_TICKS_PER_JIFFY;
	}

	/* set clock comparator for next tick */
	tmp = S390_lowcore.jiffy_timer + CPU_DEVIATION;
        asm volatile ("SCKC %0" : : "m" (tmp));

#ifdef CONFIG_SMP
	/*
	 * Do not rely on the boot cpu to do the calls to do_timer.
	 * Spread it over all cpus instead.
	 */
	write_seqlock(&xtime_lock);
	if (S390_lowcore.jiffy_timer > xtime_cc) {
		__u32 xticks;
		tmp = S390_lowcore.jiffy_timer - xtime_cc;
		if (tmp >= 2*CLK_TICKS_PER_JIFFY) {
			xticks = __div(tmp, CLK_TICKS_PER_JIFFY);
			xtime_cc += (__u64) xticks * CLK_TICKS_PER_JIFFY;
		} else {
			xticks = 1;
			xtime_cc += CLK_TICKS_PER_JIFFY;
		}
		do_timer(xticks);
	}
	write_sequnlock(&xtime_lock);
#else
	do_timer(ticks);
#endif

#ifdef CONFIG_VIRT_CPU_ACCOUNTING
	account_tick_vtime(current);
#else
	while (ticks--)
		update_process_times(user_mode(regs));
#endif

	s390_do_profile(regs);
}

#ifdef CONFIG_NO_IDLE_HZ

#ifdef CONFIG_NO_IDLE_HZ_INIT
int sysctl_hz_timer = 0;
#else
int sysctl_hz_timer = 1;
#endif

/*
 * Stop the HZ tick on the current CPU.
 * Only cpu_idle may call this function.
 */
static inline void stop_hz_timer(void)
{
	unsigned long flags;
	unsigned long seq, next;
	__u64 timer, todval;
	int cpu = smp_processor_id();

	if (sysctl_hz_timer != 0)
		return;

	cpu_set(cpu, nohz_cpu_mask);

	/*
	 * Leave the clock comparator set up for the next timer
	 * tick if either rcu or a softirq is pending.
	 */
	if (rcu_needs_cpu(cpu) || local_softirq_pending()) {
		cpu_clear(cpu, nohz_cpu_mask);
		return;
	}

	/*
	 * This cpu is going really idle. Set up the clock comparator
	 * for the next event.
	 */
	next = next_timer_interrupt();
	do {
		seq = read_seqbegin_irqsave(&xtime_lock, flags);
		timer = ((__u64) next) - ((__u64) jiffies) + jiffies_64;
	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
	todval = -1ULL;
	/* Be careful about overflows. */
	if (timer < (-1ULL / CLK_TICKS_PER_JIFFY)) {
		timer = jiffies_timer_cc + timer * CLK_TICKS_PER_JIFFY;
		if (timer >= jiffies_timer_cc)
			todval = timer;
	}
	asm volatile ("SCKC %0" : : "m" (todval));
}

/*
 * Start the HZ tick on the current CPU.
 * Only cpu_idle may call this function.
 */
static inline void start_hz_timer(void)
{
	if (!cpu_isset(smp_processor_id(), nohz_cpu_mask))
		return;
	account_ticks(task_pt_regs(current));
	cpu_clear(smp_processor_id(), nohz_cpu_mask);
}

static int nohz_idle_notify(struct notifier_block *self,
			    unsigned long action, void *hcpu)
{
	switch (action) {
	case CPU_IDLE:
		stop_hz_timer();
		break;
	case CPU_NOT_IDLE:
		start_hz_timer();
		break;
	}
	return NOTIFY_OK;
}

static struct notifier_block nohz_idle_nb = {
	.notifier_call = nohz_idle_notify,
};

void __init nohz_init(void)
{
	if (register_idle_notifier(&nohz_idle_nb))
		panic("Couldn't register idle notifier");
}

#endif

/*
 * Start the clock comparator on the current CPU.
 */
void init_cpu_timer(void)
{
	unsigned long cr0;
	__u64 timer;

	timer = jiffies_timer_cc + jiffies_64 * CLK_TICKS_PER_JIFFY;
	S390_lowcore.jiffy_timer = timer + CLK_TICKS_PER_JIFFY;
	timer += CLK_TICKS_PER_JIFFY + CPU_DEVIATION;
	asm volatile ("SCKC %0" : : "m" (timer));
        /* allow clock comparator timer interrupt */
	__ctl_store(cr0, 0, 0);
        cr0 |= 0x800;
	__ctl_load(cr0, 0, 0);
}

extern void vtime_init(void);

/*
 * Initialize the TOD clock and the CPU timer of
 * the boot cpu.
 */
void __init time_init(void)
{
	__u64 set_time_cc;
	int cc;

        /* kick the TOD clock */
	asm volatile(
		"	stck	0(%2)\n"
		"	ipm	%0\n"
		"	srl	%0,28"
		: "=d" (cc), "=m" (init_timer_cc)
		: "a" (&init_timer_cc) : "cc");
        switch (cc) {
        case 0: /* clock in set state: all is fine */
                break;
        case 1: /* clock in non-set state: FIXME */
                printk("time_init: TOD clock in non-set state\n");
                break;
        case 2: /* clock in error state: FIXME */
                printk("time_init: TOD clock in error state\n");
                break;
        case 3: /* clock in stopped or not-operational state: FIXME */
                printk("time_init: TOD clock stopped/non-operational\n");
                break;
        }
	jiffies_timer_cc = init_timer_cc - jiffies_64 * CLK_TICKS_PER_JIFFY;

	/* set xtime */
	xtime_cc = init_timer_cc + CLK_TICKS_PER_JIFFY;
	set_time_cc = init_timer_cc - 0x8126d60e46000000LL +
		(0x3c26700LL*1000000*4096);
        tod_to_timeval(set_time_cc, &xtime);
        set_normalized_timespec(&wall_to_monotonic,
                                -xtime.tv_sec, -xtime.tv_nsec);

	/* request the clock comparator external interrupt */
	if (register_early_external_interrupt(0x1004, NULL,
					      &ext_int_info_cc) != 0)
                panic("Couldn't request external interrupt 0x1004");

        init_cpu_timer();

#ifdef CONFIG_NO_IDLE_HZ
	nohz_init();
#endif

#ifdef CONFIG_VIRT_TIMER
	vtime_init();
#endif
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* arch/s390/kernel/time.c
	3	* Time of day based timer functions.
	4	*
	5	* S390 version
	6	* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
	7	* Author(s): Hartmut Penner (hp@de.ibm.com),
	8	* Martin Schwidefsky (schwidefsky@de.ibm.com),
	9	* Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
	10	*
	11	* Derived from "arch/i386/kernel/time.c"
	12	* Copyright (C) 1991, 1992, 1995 Linus Torvalds
	13	*/
	14
1da177e4 LT	15	#include <linux/errno.h>
	16	#include <linux/module.h>
	17	#include <linux/sched.h>
	18	#include <linux/kernel.h>
	19	#include <linux/param.h>
	20	#include <linux/string.h>
	21	#include <linux/mm.h>
	22	#include <linux/interrupt.h>
	23	#include <linux/time.h>
	24	#include <linux/delay.h>
	25	#include <linux/init.h>
	26	#include <linux/smp.h>
	27	#include <linux/types.h>
	28	#include <linux/profile.h>
	29	#include <linux/timex.h>
	30	#include <linux/notifier.h>
	31
	32	#include <asm/uaccess.h>
	33	#include <asm/delay.h>
	34	#include <asm/s390_ext.h>
	35	#include <asm/div64.h>
	36	#include <asm/irq.h>
	37	#include <asm/timer.h>
	38
	39	/* change this if you have some constant time drift */
	40	#define USECS_PER_JIFFY ((unsigned long) 1000000/HZ)
	41	#define CLK_TICKS_PER_JIFFY ((unsigned long) USECS_PER_JIFFY << 12)
	42
	43	/*
	44	* Create a small time difference between the timer interrupts
	45	* on the different cpus to avoid lock contention.
	46	*/
	47	#define CPU_DEVIATION (smp_processor_id() << 12)
	48
	49	#define TICK_SIZE tick
	50
1da177e4 LT	51	static ext_int_info_t ext_int_info_cc;
	52	static u64 init_timer_cc;
	53	static u64 jiffies_timer_cc;
	54	static u64 xtime_cc;
	55
1da177e4 LT	56	/*
	57	* Scheduler clock - returns current time in nanosec units.
	58	*/
	59	unsigned long long sched_clock(void)
	60	{
9dbafa53	61	return ((get_clock() - jiffies_timer_cc) * 125) >> 9;
1da177e4 LT	62	}
1da177e4 LT	63
32f65f27 JG	64	/*
	65	* Monotonic_clock - returns # of nanoseconds passed since time_init()
	66	*/
	67	unsigned long long monotonic_clock(void)
	68	{
	69	return sched_clock();
	70	}
	71	EXPORT_SYMBOL(monotonic_clock);
	72
1da177e4 LT	73	void tod_to_timeval(__u64 todval, struct timespec *xtime)
	74	{
	75	unsigned long long sec;
	76
	77	sec = todval >> 12;
	78	do_div(sec, 1000000);
	79	xtime->tv_sec = sec;
	80	todval -= (sec * 1000000) << 12;
	81	xtime->tv_nsec = ((todval * 1000) >> 12);
	82	}
	83
	84	static inline unsigned long do_gettimeoffset(void)
	85	{
	86	__u64 now;
	87
8ef38609 AN	88	now = (get_clock() - jiffies_timer_cc) >> 12;
8ef38609 AN	89	now -= (__u64) jiffies * USECS_PER_JIFFY;
1da177e4 LT	90	return (unsigned long) now;
	91	}
	92
	93	/*
	94	* This version of gettimeofday has microsecond resolution.
	95	*/
	96	void do_gettimeofday(struct timeval *tv)
	97	{
	98	unsigned long flags;
	99	unsigned long seq;
	100	unsigned long usec, sec;
	101
	102	do {
	103	seq = read_seqbegin_irqsave(&xtime_lock, flags);
	104
	105	sec = xtime.tv_sec;
	106	usec = xtime.tv_nsec / 1000 + do_gettimeoffset();
	107	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
	108
	109	while (usec >= 1000000) {
	110	usec -= 1000000;
	111	sec++;
	112	}
	113
	114	tv->tv_sec = sec;
	115	tv->tv_usec = usec;
	116	}
	117
	118	EXPORT_SYMBOL(do_gettimeofday);
	119
	120	int do_settimeofday(struct timespec *tv)
	121	{
	122	time_t wtm_sec, sec = tv->tv_sec;
	123	long wtm_nsec, nsec = tv->tv_nsec;
	124
	125	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
	126	return -EINVAL;
	127
	128	write_seqlock_irq(&xtime_lock);
	129	/* This is revolting. We need to set the xtime.tv_nsec
	130	* correctly. However, the value in this location is
	131	* is value at the last tick.
	132	* Discover what correction gettimeofday
	133	* would have done, and then undo it!
	134	*/
	135	nsec -= do_gettimeoffset() * 1000;
	136
	137	wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
	138	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
	139
	140	set_normalized_timespec(&xtime, sec, nsec);
	141	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
	142
b149ee22	143	ntp_clear();
1da177e4 LT	144	write_sequnlock_irq(&xtime_lock);
	145	clock_was_set();
	146	return 0;
	147	}
	148
	149	EXPORT_SYMBOL(do_settimeofday);
	150
	151
	152	#ifdef CONFIG_PROFILING
	153	#define s390_do_profile(regs) profile_tick(CPU_PROFILING, regs)
	154	#else
	155	#define s390_do_profile(regs) do { ; } while(0)
	156	#endif /* CONFIG_PROFILING */
	157
	158
	159	/*
	160	* timer_interrupt() needs to keep up the real-time clock,
	161	* as well as call the "do_timer()" routine every clocktick
	162	*/
	163	void account_ticks(struct pt_regs *regs)
	164	{
	165	__u64 tmp;
3171a030	166	__u32 ticks;
1da177e4 LT	167
	168	/* Calculate how many ticks have passed. */
	169	if (S390_lowcore.int_clock < S390_lowcore.jiffy_timer) {
	170	/*
	171	* We have to program the clock comparator even if
	172	* no tick has passed. That happens if e.g. an i/o
	173	* interrupt wakes up an idle processor that has
	174	* switched off its hz timer.
	175	*/
	176	tmp = S390_lowcore.jiffy_timer + CPU_DEVIATION;
	177	asm volatile ("SCKC %0" : : "m" (tmp));
	178	return;
	179	}
	180	tmp = S390_lowcore.int_clock - S390_lowcore.jiffy_timer;
	181	if (tmp >= 2CLK_TICKS_PER_JIFFY) { / more than two ticks ? */
	182	ticks = __div(tmp, CLK_TICKS_PER_JIFFY) + 1;
	183	S390_lowcore.jiffy_timer +=
	184	CLK_TICKS_PER_JIFFY * (__u64) ticks;
	185	} else if (tmp >= CLK_TICKS_PER_JIFFY) {
	186	ticks = 2;
	187	S390_lowcore.jiffy_timer += 2*CLK_TICKS_PER_JIFFY;
	188	} else {
	189	ticks = 1;
	190	S390_lowcore.jiffy_timer += CLK_TICKS_PER_JIFFY;
	191	}
	192
	193	/* set clock comparator for next tick */
	194	tmp = S390_lowcore.jiffy_timer + CPU_DEVIATION;
	195	asm volatile ("SCKC %0" : : "m" (tmp));
	196
	197	#ifdef CONFIG_SMP
	198	/*
	199	* Do not rely on the boot cpu to do the calls to do_timer.
	200	* Spread it over all cpus instead.
	201	*/
	202	write_seqlock(&xtime_lock);
	203	if (S390_lowcore.jiffy_timer > xtime_cc) {
3171a030	204	__u32 xticks;
1da177e4 LT	205	tmp = S390_lowcore.jiffy_timer - xtime_cc;
	206	if (tmp >= 2*CLK_TICKS_PER_JIFFY) {
	207	xticks = __div(tmp, CLK_TICKS_PER_JIFFY);
	208	xtime_cc += (__u64) xticks * CLK_TICKS_PER_JIFFY;
	209	} else {
	210	xticks = 1;
	211	xtime_cc += CLK_TICKS_PER_JIFFY;
	212	}
3171a030	213	do_timer(xticks);
1da177e4 LT	214	}
	215	write_sequnlock(&xtime_lock);
	216	#else
3171a030	217	do_timer(ticks);
1da177e4 LT	218	#endif
	219
	220	#ifdef CONFIG_VIRT_CPU_ACCOUNTING
1f1c12af	221	account_tick_vtime(current);
1da177e4 LT	222	#else
	223	while (ticks--)
	224	update_process_times(user_mode(regs));
	225	#endif
	226
	227	s390_do_profile(regs);
	228	}
	229
	230	#ifdef CONFIG_NO_IDLE_HZ
	231
	232	#ifdef CONFIG_NO_IDLE_HZ_INIT
	233	int sysctl_hz_timer = 0;
	234	#else
	235	int sysctl_hz_timer = 1;
	236	#endif
	237
	238	/*
	239	* Stop the HZ tick on the current CPU.
	240	* Only cpu_idle may call this function.
	241	*/
	242	static inline void stop_hz_timer(void)
	243	{
1b44e98d MS	244	unsigned long flags;
1b44e98d MS	245	unsigned long seq, next;
4b7e0706	246	__u64 timer, todval;
5afdbd6e	247	int cpu = smp_processor_id();
1da177e4 LT	248
	249	if (sysctl_hz_timer != 0)
	250	return;
	251
5afdbd6e	252	cpu_set(cpu, nohz_cpu_mask);
1da177e4 LT	253
	254	/*
	255	* Leave the clock comparator set up for the next timer
	256	* tick if either rcu or a softirq is pending.
	257	*/
5afdbd6e HC	258	if (rcu_needs_cpu(cpu) \|\| local_softirq_pending()) {
5afdbd6e HC	259	cpu_clear(cpu, nohz_cpu_mask);
1da177e4 LT	260	return;
	261	}
	262
	263	/*
	264	* This cpu is going really idle. Set up the clock comparator
	265	* for the next event.
	266	*/
1b44e98d MS	267	next = next_timer_interrupt();
	268	do {
	269	seq = read_seqbegin_irqsave(&xtime_lock, flags);
705af309	270	timer = ((__u64) next) - ((__u64) jiffies) + jiffies_64;
1b44e98d	271	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
4b7e0706 MS	272	todval = -1ULL;
	273	/* Be careful about overflows. */
	274	if (timer < (-1ULL / CLK_TICKS_PER_JIFFY)) {
	275	timer = jiffies_timer_cc + timer * CLK_TICKS_PER_JIFFY;
	276	if (timer >= jiffies_timer_cc)
	277	todval = timer;
	278	}
	279	asm volatile ("SCKC %0" : : "m" (todval));
1da177e4 LT	280	}
	281
	282	/*
	283	* Start the HZ tick on the current CPU.
	284	* Only cpu_idle may call this function.
	285	*/
	286	static inline void start_hz_timer(void)
	287	{
	288	if (!cpu_isset(smp_processor_id(), nohz_cpu_mask))
	289	return;
c7584fb6	290	account_ticks(task_pt_regs(current));
1da177e4 LT	291	cpu_clear(smp_processor_id(), nohz_cpu_mask);
	292	}
	293
	294	static int nohz_idle_notify(struct notifier_block *self,
	295	unsigned long action, void *hcpu)
	296	{
	297	switch (action) {
	298	case CPU_IDLE:
	299	stop_hz_timer();
	300	break;
	301	case CPU_NOT_IDLE:
	302	start_hz_timer();
	303	break;
	304	}
	305	return NOTIFY_OK;
	306	}
	307
	308	static struct notifier_block nohz_idle_nb = {
	309	.notifier_call = nohz_idle_notify,
	310	};
	311
	312	void __init nohz_init(void)
	313	{
	314	if (register_idle_notifier(&nohz_idle_nb))
	315	panic("Couldn't register idle notifier");
	316	}
	317
	318	#endif
	319
	320	/*
	321	* Start the clock comparator on the current CPU.
	322	*/
	323	void init_cpu_timer(void)
	324	{
	325	unsigned long cr0;
	326	__u64 timer;
	327
	328	timer = jiffies_timer_cc + jiffies_64 * CLK_TICKS_PER_JIFFY;
	329	S390_lowcore.jiffy_timer = timer + CLK_TICKS_PER_JIFFY;
	330	timer += CLK_TICKS_PER_JIFFY + CPU_DEVIATION;
	331	asm volatile ("SCKC %0" : : "m" (timer));
	332	/* allow clock comparator timer interrupt */
	333	__ctl_store(cr0, 0, 0);
	334	cr0 \|= 0x800;
	335	__ctl_load(cr0, 0, 0);
	336	}
	337
	338	extern void vtime_init(void);
	339
	340	/*
	341	* Initialize the TOD clock and the CPU timer of
	342	* the boot cpu.
	343	*/
	344	void __init time_init(void)
	345	{
	346	__u64 set_time_cc;
	347	int cc;
	348
	349	/* kick the TOD clock */
94c12cc7 MS	350	asm volatile(
	351	" stck 0(%2)\n"
	352	" ipm %0\n"
	353	" srl %0,28"
	354	: "=d" (cc), "=m" (init_timer_cc)
	355	: "a" (&init_timer_cc) : "cc");
1da177e4 LT	356	switch (cc) {
	357	case 0: /* clock in set state: all is fine */
	358	break;
	359	case 1: /* clock in non-set state: FIXME */
	360	printk("time_init: TOD clock in non-set state\n");
	361	break;
	362	case 2: /* clock in error state: FIXME */
	363	printk("time_init: TOD clock in error state\n");
	364	break;
	365	case 3: /* clock in stopped or not-operational state: FIXME */
	366	printk("time_init: TOD clock stopped/non-operational\n");
	367	break;
	368	}
	369	jiffies_timer_cc = init_timer_cc - jiffies_64 * CLK_TICKS_PER_JIFFY;
	370
	371	/* set xtime */
	372	xtime_cc = init_timer_cc + CLK_TICKS_PER_JIFFY;
	373	set_time_cc = init_timer_cc - 0x8126d60e46000000LL +
	374	(0x3c26700LL10000004096);
	375	tod_to_timeval(set_time_cc, &xtime);
	376	set_normalized_timespec(&wall_to_monotonic,
	377	-xtime.tv_sec, -xtime.tv_nsec);
	378
	379	/* request the clock comparator external interrupt */
d2c993d8	380	if (register_early_external_interrupt(0x1004, NULL,
1da177e4 LT	381	&ext_int_info_cc) != 0)
	382	panic("Couldn't request external interrupt 0x1004");
	383
	384	init_cpu_timer();
	385
	386	#ifdef CONFIG_NO_IDLE_HZ
	387	nohz_init();
	388	#endif
	389
	390	#ifdef CONFIG_VIRT_TIMER
	391	vtime_init();
	392	#endif
	393	}
	394