/* *  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/config.h>#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 ticku64 jiffies_64 = INITIAL_JIFFIES;EXPORT_SYMBOL(jiffies_64);static ext_int_info_t ext_int_info_cc;static u64 init_timer_cc;static u64 jiffies_timer_cc;static u64 xtime_cc;extern unsigned long wall_jiffies;/* * Scheduler clock - returns current time in nanosec units. */unsigned long long sched_clock(void){	return ((get_clock() - jiffies_timer_cc) * 1000) >> 12;}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;	/* We require the offset from the latest update of xtime */	now -= (__u64) wall_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);	time_adjust = 0;		/* stop active adjtime() */	time_status |= STA_UNSYNC;	time_maxerror = NTP_PHASE_LIMIT;	time_esterror = NTP_PHASE_LIMIT;	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, xticks;	/* Calculate how many ticks have passed. */	if (S390_lowcore.int_clock < S390_lowcore.jiffy_timer)		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) {		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;		}		while (xticks--)			do_timer(regs);	}	write_sequnlock(&xtime_lock);#else	for (xticks = ticks; xticks > 0; xticks--)		do_timer(regs);#endif#ifdef CONFIG_VIRT_CPU_ACCOUNTING	account_user_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_INITint sysctl_hz_timer = 0;#elseint 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){	__u64 timer;	if (sysctl_hz_timer != 0)		return;	cpu_set(smp_processor_id(), nohz_cpu_mask);	/*	 * Leave the clock comparator set up for the next timer	 * tick if either rcu or a softirq is pending.	 */	if (rcu_pending(smp_processor_id()) || local_softirq_pending()) {		cpu_clear(smp_processor_id(), nohz_cpu_mask);		return;	}	/*	 * This cpu is going really idle. Set up the clock comparator	 * for the next event.	 */	timer = (__u64) (next_timer_interrupt() - jiffies) + jiffies_64;	timer = jiffies_timer_cc + timer * CLK_TICKS_PER_JIFFY;	asm volatile ("SCKC %0" : : "m" (timer));}/* * 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(__KSTK_PTREGS(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(%1)\n\t"                      "IPM  %0\n\t"                      "SRL  %0,28" : "=r" (cc) : "a" (&init_timer_cc) 				   : "memory", "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, 0,					      &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}