time.c 45.8 KB
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/*
 *  arch/s390/kernel/time.c
 *    Time of day based timer functions.
 *
 *  S390 version
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 *    Copyright IBM Corp. 1999, 2008
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 *    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
 */

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#define KMSG_COMPONENT "time"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

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#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>
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#include <linux/cpu.h>
#include <linux/stop_machine.h>
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#include <linux/time.h>
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#include <linux/sysdev.h>
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#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>
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#include <linux/clocksource.h>
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#include <linux/clockchips.h>
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#include <asm/uaccess.h>
#include <asm/delay.h>
#include <asm/s390_ext.h>
#include <asm/div64.h>
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#include <asm/vdso.h>
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#include <asm/irq.h>
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#include <asm/irq_regs.h>
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#include <asm/timer.h>
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#include <asm/etr.h>
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#include <asm/cio.h>
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/* 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

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u64 sched_clock_base_cc = -1;	/* Force to data section. */

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static DEFINE_PER_CPU(struct clock_event_device, comparators);
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/*
 * Scheduler clock - returns current time in nanosec units.
 */
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unsigned long long notrace sched_clock(void)
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{
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	return ((get_clock_xt() - sched_clock_base_cc) * 125) >> 9;
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}

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

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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);
}

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void clock_comparator_work(void)
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{
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	struct clock_event_device *cd;
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	S390_lowcore.clock_comparator = -1ULL;
	set_clock_comparator(S390_lowcore.clock_comparator);
	cd = &__get_cpu_var(comparators);
	cd->event_handler(cd);
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}

/*
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 * Fixup the clock comparator.
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 */
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static void fixup_clock_comparator(unsigned long long delta)
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{
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	/* If nobody is waiting there's nothing to fix. */
	if (S390_lowcore.clock_comparator == -1ULL)
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		return;
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	S390_lowcore.clock_comparator += delta;
	set_clock_comparator(S390_lowcore.clock_comparator);
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}

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static int s390_next_event(unsigned long delta,
			   struct clock_event_device *evt)
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{
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	S390_lowcore.clock_comparator = get_clock() + delta;
	set_clock_comparator(S390_lowcore.clock_comparator);
	return 0;
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}

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static void s390_set_mode(enum clock_event_mode mode,
			  struct clock_event_device *evt)
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{
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}

/*
 * Set up lowcore and control register of the current cpu to
 * enable TOD clock and clock comparator interrupts.
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 */
void init_cpu_timer(void)
{
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	struct clock_event_device *cd;
	int cpu;

	S390_lowcore.clock_comparator = -1ULL;
	set_clock_comparator(S390_lowcore.clock_comparator);

	cpu = smp_processor_id();
	cd = &per_cpu(comparators, cpu);
	cd->name		= "comparator";
	cd->features		= CLOCK_EVT_FEAT_ONESHOT;
	cd->mult		= 16777;
	cd->shift		= 12;
	cd->min_delta_ns	= 1;
	cd->max_delta_ns	= LONG_MAX;
	cd->rating		= 400;
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	cd->cpumask		= cpumask_of(cpu);
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	cd->set_next_event	= s390_next_event;
	cd->set_mode		= s390_set_mode;

	clockevents_register_device(cd);
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	/* Enable clock comparator timer interrupt. */
	__ctl_set_bit(0,11);

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	/* Always allow the timing alert external interrupt. */
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	__ctl_set_bit(0, 4);
}

static void clock_comparator_interrupt(__u16 code)
{
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	if (S390_lowcore.clock_comparator == -1ULL)
		set_clock_comparator(S390_lowcore.clock_comparator);
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}

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static void etr_timing_alert(struct etr_irq_parm *);
static void stp_timing_alert(struct stp_irq_parm *);

static void timing_alert_interrupt(__u16 code)
{
	if (S390_lowcore.ext_params & 0x00c40000)
		etr_timing_alert((struct etr_irq_parm *)
				 &S390_lowcore.ext_params);
	if (S390_lowcore.ext_params & 0x00038000)
		stp_timing_alert((struct stp_irq_parm *)
				 &S390_lowcore.ext_params);
}

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static void etr_reset(void);
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static void stp_reset(void);
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unsigned long read_persistent_clock(void)
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{
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	struct timespec ts;
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	tod_to_timeval(get_clock() - TOD_UNIX_EPOCH, &ts);
	return ts.tv_sec;
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}

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static cycle_t read_tod_clock(struct clocksource *cs)
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{
	return get_clock();
}

static struct clocksource clocksource_tod = {
	.name		= "tod",
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	.rating		= 400,
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	.read		= read_tod_clock,
	.mask		= -1ULL,
	.mult		= 1000,
	.shift		= 12,
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	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
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};

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struct clocksource * __init clocksource_default_clock(void)
{
	return &clocksource_tod;
}
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void update_vsyscall(struct timespec *wall_time, struct clocksource *clock)
{
	if (clock != &clocksource_tod)
		return;

	/* Make userspace gettimeofday spin until we're done. */
	++vdso_data->tb_update_count;
	smp_wmb();
	vdso_data->xtime_tod_stamp = clock->cycle_last;
	vdso_data->xtime_clock_sec = xtime.tv_sec;
	vdso_data->xtime_clock_nsec = xtime.tv_nsec;
	vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
	vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
	smp_wmb();
	++vdso_data->tb_update_count;
}

extern struct timezone sys_tz;

void update_vsyscall_tz(void)
{
	/* Make userspace gettimeofday spin until we're done. */
	++vdso_data->tb_update_count;
	smp_wmb();
	vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
	vdso_data->tz_dsttime = sys_tz.tz_dsttime;
	smp_wmb();
	++vdso_data->tb_update_count;
}

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/*
 * Initialize the TOD clock and the CPU timer of
 * the boot cpu.
 */
void __init time_init(void)
{
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	struct timespec ts;
	unsigned long flags;
	cycle_t now;

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	/* Reset time synchronization interfaces. */
	etr_reset();
	stp_reset();
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	/* request the clock comparator external interrupt */
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	if (register_external_interrupt(0x1004, clock_comparator_interrupt))
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                panic("Couldn't request external interrupt 0x1004");

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	/* request the timing alert external interrupt */
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	if (register_external_interrupt(0x1406, timing_alert_interrupt))
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		panic("Couldn't request external interrupt 0x1406");

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	if (clocksource_register(&clocksource_tod) != 0)
		panic("Could not register TOD clock source");

	/*
	 * The TOD clock is an accurate clock. The xtime should be
	 * initialized in a way that the difference between TOD and
	 * xtime is reasonably small. Too bad that timekeeping_init
	 * sets xtime.tv_nsec to zero. In addition the clock source
	 * change from the jiffies clock source to the TOD clock
	 * source add another error of up to 1/HZ second. The same
	 * function sets wall_to_monotonic to a value that is too
	 * small for /proc/uptime to be accurate.
	 * Reset xtime and wall_to_monotonic to sane values.
	 */
	write_seqlock_irqsave(&xtime_lock, flags);
	now = get_clock();
	tod_to_timeval(now - TOD_UNIX_EPOCH, &xtime);
	clocksource_tod.cycle_last = now;
	tod_to_timeval(sched_clock_base_cc - TOD_UNIX_EPOCH, &ts);
	set_normalized_timespec(&wall_to_monotonic, -ts.tv_sec, -ts.tv_nsec);
	write_sequnlock_irqrestore(&xtime_lock, flags);

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	/* Enable TOD clock interrupts on the boot cpu. */
	init_cpu_timer();
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	/* Enable cpu timer interrupts on the boot cpu. */
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	vtime_init();
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}

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/*
 * The time is "clock". old is what we think the time is.
 * Adjust the value by a multiple of jiffies and add the delta to ntp.
 * "delay" is an approximation how long the synchronization took. If
 * the time correction is positive, then "delay" is subtracted from
 * the time difference and only the remaining part is passed to ntp.
 */
static unsigned long long adjust_time(unsigned long long old,
				      unsigned long long clock,
				      unsigned long long delay)
{
	unsigned long long delta, ticks;
	struct timex adjust;

	if (clock > old) {
		/* It is later than we thought. */
		delta = ticks = clock - old;
		delta = ticks = (delta < delay) ? 0 : delta - delay;
		delta -= do_div(ticks, CLK_TICKS_PER_JIFFY);
		adjust.offset = ticks * (1000000 / HZ);
	} else {
		/* It is earlier than we thought. */
		delta = ticks = old - clock;
		delta -= do_div(ticks, CLK_TICKS_PER_JIFFY);
		delta = -delta;
		adjust.offset = -ticks * (1000000 / HZ);
	}
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	sched_clock_base_cc += delta;
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	if (adjust.offset != 0) {
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		pr_notice("The ETR interface has adjusted the clock "
			  "by %li microseconds\n", adjust.offset);
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		adjust.modes = ADJ_OFFSET_SINGLESHOT;
		do_adjtimex(&adjust);
	}
	return delta;
}

static DEFINE_PER_CPU(atomic_t, clock_sync_word);
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static DEFINE_MUTEX(clock_sync_mutex);
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static unsigned long clock_sync_flags;

#define CLOCK_SYNC_HAS_ETR	0
#define CLOCK_SYNC_HAS_STP	1
#define CLOCK_SYNC_ETR		2
#define CLOCK_SYNC_STP		3

/*
 * The synchronous get_clock function. It will write the current clock
 * value to the clock pointer and return 0 if the clock is in sync with
 * the external time source. If the clock mode is local it will return
 * -ENOSYS and -EAGAIN if the clock is not in sync with the external
 * reference.
 */
int get_sync_clock(unsigned long long *clock)
{
	atomic_t *sw_ptr;
	unsigned int sw0, sw1;

	sw_ptr = &get_cpu_var(clock_sync_word);
	sw0 = atomic_read(sw_ptr);
	*clock = get_clock();
	sw1 = atomic_read(sw_ptr);
	put_cpu_var(clock_sync_sync);
	if (sw0 == sw1 && (sw0 & 0x80000000U))
		/* Success: time is in sync. */
		return 0;
	if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags) &&
	    !test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
		return -ENOSYS;
	if (!test_bit(CLOCK_SYNC_ETR, &clock_sync_flags) &&
	    !test_bit(CLOCK_SYNC_STP, &clock_sync_flags))
		return -EACCES;
	return -EAGAIN;
}
EXPORT_SYMBOL(get_sync_clock);

/*
 * Make get_sync_clock return -EAGAIN.
 */
static void disable_sync_clock(void *dummy)
{
	atomic_t *sw_ptr = &__get_cpu_var(clock_sync_word);
	/*
	 * Clear the in-sync bit 2^31. All get_sync_clock calls will
	 * fail until the sync bit is turned back on. In addition
	 * increase the "sequence" counter to avoid the race of an
	 * etr event and the complete recovery against get_sync_clock.
	 */
	atomic_clear_mask(0x80000000, sw_ptr);
	atomic_inc(sw_ptr);
}

/*
 * Make get_sync_clock return 0 again.
 * Needs to be called from a context disabled for preemption.
 */
static void enable_sync_clock(void)
{
	atomic_t *sw_ptr = &__get_cpu_var(clock_sync_word);
	atomic_set_mask(0x80000000, sw_ptr);
}

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/*
 * Function to check if the clock is in sync.
 */
static inline int check_sync_clock(void)
{
	atomic_t *sw_ptr;
	int rc;

	sw_ptr = &get_cpu_var(clock_sync_word);
	rc = (atomic_read(sw_ptr) & 0x80000000U) != 0;
	put_cpu_var(clock_sync_sync);
	return rc;
}

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/* Single threaded workqueue used for etr and stp sync events */
static struct workqueue_struct *time_sync_wq;

static void __init time_init_wq(void)
{
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	if (time_sync_wq)
		return;
	time_sync_wq = create_singlethread_workqueue("timesync");
	stop_machine_create();
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}

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/*
 * External Time Reference (ETR) code.
 */
static int etr_port0_online;
static int etr_port1_online;
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static int etr_steai_available;
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static int __init early_parse_etr(char *p)
{
	if (strncmp(p, "off", 3) == 0)
		etr_port0_online = etr_port1_online = 0;
	else if (strncmp(p, "port0", 5) == 0)
		etr_port0_online = 1;
	else if (strncmp(p, "port1", 5) == 0)
		etr_port1_online = 1;
	else if (strncmp(p, "on", 2) == 0)
		etr_port0_online = etr_port1_online = 1;
	return 0;
}
early_param("etr", early_parse_etr);

enum etr_event {
	ETR_EVENT_PORT0_CHANGE,
	ETR_EVENT_PORT1_CHANGE,
	ETR_EVENT_PORT_ALERT,
	ETR_EVENT_SYNC_CHECK,
	ETR_EVENT_SWITCH_LOCAL,
	ETR_EVENT_UPDATE,
};

/*
 * Valid bit combinations of the eacr register are (x = don't care):
 * e0 e1 dp p0 p1 ea es sl
 *  0  0  x  0	0  0  0  0  initial, disabled state
 *  0  0  x  0	1  1  0  0  port 1 online
 *  0  0  x  1	0  1  0  0  port 0 online
 *  0  0  x  1	1  1  0  0  both ports online
 *  0  1  x  0	1  1  0  0  port 1 online and usable, ETR or PPS mode
 *  0  1  x  0	1  1  0  1  port 1 online, usable and ETR mode
 *  0  1  x  0	1  1  1  0  port 1 online, usable, PPS mode, in-sync
 *  0  1  x  0	1  1  1  1  port 1 online, usable, ETR mode, in-sync
 *  0  1  x  1	1  1  0  0  both ports online, port 1 usable
 *  0  1  x  1	1  1  1  0  both ports online, port 1 usable, PPS mode, in-sync
 *  0  1  x  1	1  1  1  1  both ports online, port 1 usable, ETR mode, in-sync
 *  1  0  x  1	0  1  0  0  port 0 online and usable, ETR or PPS mode
 *  1  0  x  1	0  1  0  1  port 0 online, usable and ETR mode
 *  1  0  x  1	0  1  1  0  port 0 online, usable, PPS mode, in-sync
 *  1  0  x  1	0  1  1  1  port 0 online, usable, ETR mode, in-sync
 *  1  0  x  1	1  1  0  0  both ports online, port 0 usable
 *  1  0  x  1	1  1  1  0  both ports online, port 0 usable, PPS mode, in-sync
 *  1  0  x  1	1  1  1  1  both ports online, port 0 usable, ETR mode, in-sync
 *  1  1  x  1	1  1  1  0  both ports online & usable, ETR, in-sync
 *  1  1  x  1	1  1  1  1  both ports online & usable, ETR, in-sync
 */
static struct etr_eacr etr_eacr;
static u64 etr_tolec;			/* time of last eacr update */
static struct etr_aib etr_port0;
static int etr_port0_uptodate;
static struct etr_aib etr_port1;
static int etr_port1_uptodate;
static unsigned long etr_events;
static struct timer_list etr_timer;

static void etr_timeout(unsigned long dummy);
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static void etr_work_fn(struct work_struct *work);
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static DEFINE_MUTEX(etr_work_mutex);
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static DECLARE_WORK(etr_work, etr_work_fn);
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/*
 * Reset ETR attachment.
 */
static void etr_reset(void)
{
	etr_eacr =  (struct etr_eacr) {
		.e0 = 0, .e1 = 0, ._pad0 = 4, .dp = 0,
		.p0 = 0, .p1 = 0, ._pad1 = 0, .ea = 0,
		.es = 0, .sl = 0 };
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	if (etr_setr(&etr_eacr) == 0) {
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		etr_tolec = get_clock();
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		set_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags);
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		if (etr_port0_online && etr_port1_online)
			set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
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	} else if (etr_port0_online || etr_port1_online) {
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		pr_warning("The real or virtual hardware system does "
			   "not provide an ETR interface\n");
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		etr_port0_online = etr_port1_online = 0;
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	}
}

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static int __init etr_init(void)
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{
	struct etr_aib aib;

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	if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags))
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		return 0;
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	time_init_wq();
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	/* Check if this machine has the steai instruction. */
	if (etr_steai(&aib, ETR_STEAI_STEPPING_PORT) == 0)
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		etr_steai_available = 1;
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	setup_timer(&etr_timer, etr_timeout, 0UL);
	if (etr_port0_online) {
		set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
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		queue_work(time_sync_wq, &etr_work);
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	}
	if (etr_port1_online) {
		set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
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		queue_work(time_sync_wq, &etr_work);
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	}
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	return 0;
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}

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arch_initcall(etr_init);

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/*
 * Two sorts of ETR machine checks. The architecture reads:
 * "When a machine-check niterruption occurs and if a switch-to-local or
 *  ETR-sync-check interrupt request is pending but disabled, this pending
 *  disabled interruption request is indicated and is cleared".
 * Which means that we can get etr_switch_to_local events from the machine
 * check handler although the interruption condition is disabled. Lovely..
 */

/*
 * Switch to local machine check. This is called when the last usable
 * ETR port goes inactive. After switch to local the clock is not in sync.
 */
void etr_switch_to_local(void)
{
	if (!etr_eacr.sl)
		return;
551
	disable_sync_clock(NULL);
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	set_bit(ETR_EVENT_SWITCH_LOCAL, &etr_events);
553
	queue_work(time_sync_wq, &etr_work);
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}

/*
 * ETR sync check machine check. This is called when the ETR OTE and the
 * local clock OTE are farther apart than the ETR sync check tolerance.
 * After a ETR sync check the clock is not in sync. The machine check
 * is broadcasted to all cpus at the same time.
 */
void etr_sync_check(void)
{
	if (!etr_eacr.es)
		return;
566
	disable_sync_clock(NULL);
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	set_bit(ETR_EVENT_SYNC_CHECK, &etr_events);
568
	queue_work(time_sync_wq, &etr_work);
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}

/*
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 * ETR timing alert. There are two causes:
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 * 1) port state change, check the usability of the port
 * 2) port alert, one of the ETR-data-validity bits (v1-v2 bits of the
 *    sldr-status word) or ETR-data word 1 (edf1) or ETR-data word 3 (edf3)
 *    or ETR-data word 4 (edf4) has changed.
 */
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static void etr_timing_alert(struct etr_irq_parm *intparm)
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{
	if (intparm->pc0)
		/* ETR port 0 state change. */
		set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
	if (intparm->pc1)
		/* ETR port 1 state change. */
		set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
	if (intparm->eai)
		/*
		 * ETR port alert on either port 0, 1 or both.
		 * Both ports are not up-to-date now.
		 */
		set_bit(ETR_EVENT_PORT_ALERT, &etr_events);
592
	queue_work(time_sync_wq, &etr_work);
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}

static void etr_timeout(unsigned long dummy)
{
	set_bit(ETR_EVENT_UPDATE, &etr_events);
598
	queue_work(time_sync_wq, &etr_work);
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}

/*
 * Check if the etr mode is pss.
 */
static inline int etr_mode_is_pps(struct etr_eacr eacr)
{
	return eacr.es && !eacr.sl;
}

/*
 * Check if the etr mode is etr.
 */
static inline int etr_mode_is_etr(struct etr_eacr eacr)
{
	return eacr.es && eacr.sl;
}

/*
 * Check if the port can be used for TOD synchronization.
 * For PPS mode the port has to receive OTEs. For ETR mode
 * the port has to receive OTEs, the ETR stepping bit has to
 * be zero and the validity bits for data frame 1, 2, and 3
 * have to be 1.
 */
static int etr_port_valid(struct etr_aib *aib, int port)
{
	unsigned int psc;

	/* Check that this port is receiving OTEs. */
	if (aib->tsp == 0)
		return 0;

	psc = port ? aib->esw.psc1 : aib->esw.psc0;
	if (psc == etr_lpsc_pps_mode)
		return 1;
	if (psc == etr_lpsc_operational_step)
		return !aib->esw.y && aib->slsw.v1 &&
			aib->slsw.v2 && aib->slsw.v3;
	return 0;
}

/*
 * Check if two ports are on the same network.
 */
static int etr_compare_network(struct etr_aib *aib1, struct etr_aib *aib2)
{
	// FIXME: any other fields we have to compare?
	return aib1->edf1.net_id == aib2->edf1.net_id;
}

/*
 * Wrapper for etr_stei that converts physical port states
 * to logical port states to be consistent with the output
 * of stetr (see etr_psc vs. etr_lpsc).
 */
static void etr_steai_cv(struct etr_aib *aib, unsigned int func)
{
	BUG_ON(etr_steai(aib, func) != 0);
	/* Convert port state to logical port state. */
	if (aib->esw.psc0 == 1)
		aib->esw.psc0 = 2;
	else if (aib->esw.psc0 == 0 && aib->esw.p == 0)
		aib->esw.psc0 = 1;
	if (aib->esw.psc1 == 1)
		aib->esw.psc1 = 2;
	else if (aib->esw.psc1 == 0 && aib->esw.p == 1)
		aib->esw.psc1 = 1;
}

/*
 * Check if the aib a2 is still connected to the same attachment as
 * aib a1, the etv values differ by one and a2 is valid.
 */
static int etr_aib_follows(struct etr_aib *a1, struct etr_aib *a2, int p)
{
	int state_a1, state_a2;

	/* Paranoia check: e0/e1 should better be the same. */
	if (a1->esw.eacr.e0 != a2->esw.eacr.e0 ||
	    a1->esw.eacr.e1 != a2->esw.eacr.e1)
		return 0;

	/* Still connected to the same etr ? */
	state_a1 = p ? a1->esw.psc1 : a1->esw.psc0;
	state_a2 = p ? a2->esw.psc1 : a2->esw.psc0;
	if (state_a1 == etr_lpsc_operational_step) {
		if (state_a2 != etr_lpsc_operational_step ||
		    a1->edf1.net_id != a2->edf1.net_id ||
		    a1->edf1.etr_id != a2->edf1.etr_id ||
		    a1->edf1.etr_pn != a2->edf1.etr_pn)
			return 0;
	} else if (state_a2 != etr_lpsc_pps_mode)
		return 0;

	/* The ETV value of a2 needs to be ETV of a1 + 1. */
	if (a1->edf2.etv + 1 != a2->edf2.etv)
		return 0;

	if (!etr_port_valid(a2, p))
		return 0;

	return 1;
}

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struct clock_sync_data {
705
	atomic_t cpus;
706 707
	int in_sync;
	unsigned long long fixup_cc;
708 709
	int etr_port;
	struct etr_aib *etr_aib;
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};
711

712
static void clock_sync_cpu(struct clock_sync_data *sync)
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{
714
	atomic_dec(&sync->cpus);
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	enable_sync_clock();
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	/*
	 * This looks like a busy wait loop but it isn't. etr_sync_cpus
	 * is called on all other cpus while the TOD clocks is stopped.
	 * __udelay will stop the cpu on an enabled wait psw until the
	 * TOD is running again.
	 */
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	while (sync->in_sync == 0) {
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		__udelay(1);
724 725 726 727 728 729
		/*
		 * A different cpu changes *in_sync. Therefore use
		 * barrier() to force memory access.
		 */
		barrier();
	}
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	if (sync->in_sync != 1)
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		/* Didn't work. Clear per-cpu in sync bit again. */
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		disable_sync_clock(NULL);
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	/*
	 * This round of TOD syncing is done. Set the clock comparator
	 * to the next tick and let the processor continue.
	 */
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	fixup_clock_comparator(sync->fixup_cc);
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}

/*
 * Sync the TOD clock using the port refered to by aibp. This port
 * has to be enabled and the other port has to be disabled. The
 * last eacr update has to be more than 1.6 seconds in the past.
 */
745
static int etr_sync_clock(void *data)
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{
747
	static int first;
748
	unsigned long long clock, old_clock, delay, delta;
749 750 751
	struct clock_sync_data *etr_sync;
	struct etr_aib *sync_port, *aib;
	int port;
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	int rc;

754
	etr_sync = data;
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756 757 758 759 760 761 762 763 764 765 766 767 768
	if (xchg(&first, 1) == 1) {
		/* Slave */
		clock_sync_cpu(etr_sync);
		return 0;
	}

	/* Wait until all other cpus entered the sync function. */
	while (atomic_read(&etr_sync->cpus) != 0)
		cpu_relax();

	port = etr_sync->etr_port;
	aib = etr_sync->etr_aib;
	sync_port = (port == 0) ? &etr_port0 : &etr_port1;
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	enable_sync_clock();
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	/* Set clock to next OTE. */
	__ctl_set_bit(14, 21);
	__ctl_set_bit(0, 29);
	clock = ((unsigned long long) (aib->edf2.etv + 1)) << 32;
775
	old_clock = get_clock();
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	if (set_clock(clock) == 0) {
		__udelay(1);	/* Wait for the clock to start. */
		__ctl_clear_bit(0, 29);
		__ctl_clear_bit(14, 21);
		etr_stetr(aib);
		/* Adjust Linux timing variables. */
		delay = (unsigned long long)
			(aib->edf2.etv - sync_port->edf2.etv) << 32;
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		delta = adjust_time(old_clock, clock, delay);
785
		etr_sync->fixup_cc = delta;
786
		fixup_clock_comparator(delta);
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		/* Verify that the clock is properly set. */
		if (!etr_aib_follows(sync_port, aib, port)) {
			/* Didn't work. */
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			disable_sync_clock(NULL);
791
			etr_sync->in_sync = -EAGAIN;
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			rc = -EAGAIN;
		} else {
794
			etr_sync->in_sync = 1;
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			rc = 0;
		}
	} else {
		/* Could not set the clock ?!? */
		__ctl_clear_bit(0, 29);
		__ctl_clear_bit(14, 21);
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		disable_sync_clock(NULL);
802
		etr_sync->in_sync = -EAGAIN;
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		rc = -EAGAIN;
	}
805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828
	xchg(&first, 0);
	return rc;
}

static int etr_sync_clock_stop(struct etr_aib *aib, int port)
{
	struct clock_sync_data etr_sync;
	struct etr_aib *sync_port;
	int follows;
	int rc;

	/* Check if the current aib is adjacent to the sync port aib. */
	sync_port = (port == 0) ? &etr_port0 : &etr_port1;
	follows = etr_aib_follows(sync_port, aib, port);
	memcpy(sync_port, aib, sizeof(*aib));
	if (!follows)
		return -EAGAIN;
	memset(&etr_sync, 0, sizeof(etr_sync));
	etr_sync.etr_aib = aib;
	etr_sync.etr_port = port;
	get_online_cpus();
	atomic_set(&etr_sync.cpus, num_online_cpus() - 1);
	rc = stop_machine(etr_sync_clock, &etr_sync, &cpu_online_map);
	put_online_cpus();
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	return rc;
}

/*
 * Handle the immediate effects of the different events.
 * The port change event is used for online/offline changes.
 */
static struct etr_eacr etr_handle_events(struct etr_eacr eacr)
{
	if (test_and_clear_bit(ETR_EVENT_SYNC_CHECK, &etr_events))
		eacr.es = 0;
	if (test_and_clear_bit(ETR_EVENT_SWITCH_LOCAL, &etr_events))
		eacr.es = eacr.sl = 0;
	if (test_and_clear_bit(ETR_EVENT_PORT_ALERT, &etr_events))
		etr_port0_uptodate = etr_port1_uptodate = 0;

	if (test_and_clear_bit(ETR_EVENT_PORT0_CHANGE, &etr_events)) {
		if (eacr.e0)
			/*
			 * Port change of an enabled port. We have to
			 * assume that this can have caused an stepping
			 * port switch.
			 */
			etr_tolec = get_clock();
		eacr.p0 = etr_port0_online;
		if (!eacr.p0)
			eacr.e0 = 0;
		etr_port0_uptodate = 0;
	}
	if (test_and_clear_bit(ETR_EVENT_PORT1_CHANGE, &etr_events)) {
		if (eacr.e1)
			/*
			 * Port change of an enabled port. We have to
			 * assume that this can have caused an stepping
			 * port switch.
			 */
			etr_tolec = get_clock();
		eacr.p1 = etr_port1_online;
		if (!eacr.p1)
			eacr.e1 = 0;
		etr_port1_uptodate = 0;
	}
	clear_bit(ETR_EVENT_UPDATE, &etr_events);
	return eacr;
}

/*
 * Set up a timer that expires after the etr_tolec + 1.6 seconds if
 * one of the ports needs an update.
 */
static void etr_set_tolec_timeout(unsigned long long now)
{
	unsigned long micros;

	if ((!etr_eacr.p0 || etr_port0_uptodate) &&
	    (!etr_eacr.p1 || etr_port1_uptodate))
		return;
	micros = (now > etr_tolec) ? ((now - etr_tolec) >> 12) : 0;
	micros = (micros > 1600000) ? 0 : 1600000 - micros;
	mod_timer(&etr_timer, jiffies + (micros * HZ) / 1000000 + 1);
}

/*
 * Set up a time that expires after 1/2 second.
 */
static void etr_set_sync_timeout(void)
{
	mod_timer(&etr_timer, jiffies + HZ/2);
}

/*
 * Update the aib information for one or both ports.
 */
static struct etr_eacr etr_handle_update(struct etr_aib *aib,
					 struct etr_eacr eacr)
{
	/* With both ports disabled the aib information is useless. */
	if (!eacr.e0 && !eacr.e1)
		return eacr;

909
	/* Update port0 or port1 with aib stored in etr_work_fn. */
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	if (aib->esw.q == 0) {
		/* Information for port 0 stored. */
		if (eacr.p0 && !etr_port0_uptodate) {
			etr_port0 = *aib;
			if (etr_port0_online)
				etr_port0_uptodate = 1;
		}
	} else {
		/* Information for port 1 stored. */
		if (eacr.p1 && !etr_port1_uptodate) {
			etr_port1 = *aib;
			if (etr_port0_online)
				etr_port1_uptodate = 1;
		}
	}

	/*
	 * Do not try to get the alternate port aib if the clock
	 * is not in sync yet.
	 */
930
	if (!check_sync_clock())
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		return eacr;

	/*
	 * If steai is available we can get the information about
	 * the other port immediately. If only stetr is available the
	 * data-port bit toggle has to be used.
	 */
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	if (etr_steai_available) {
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		if (eacr.p0 && !etr_port0_uptodate) {
			etr_steai_cv(&etr_port0, ETR_STEAI_PORT_0);
			etr_port0_uptodate = 1;
		}
		if (eacr.p1 && !etr_port1_uptodate) {
			etr_steai_cv(&etr_port1, ETR_STEAI_PORT_1);
			etr_port1_uptodate = 1;
		}
	} else {
		/*
		 * One port was updated above, if the other
		 * port is not uptodate toggle dp bit.
		 */
		if ((eacr.p0 && !etr_port0_uptodate) ||
		    (eacr.p1 && !etr_port1_uptodate))
			eacr.dp ^= 1;
		else
			eacr.dp = 0;
	}
	return eacr;
}

/*
 * Write new etr control register if it differs from the current one.
 * Return 1 if etr_tolec has been updated as well.
 */
static void etr_update_eacr(struct etr_eacr eacr)
{
	int dp_changed;

	if (memcmp(&etr_eacr, &eacr, sizeof(eacr)) == 0)
		/* No change, return. */
		return;
	/*
	 * The disable of an active port of the change of the data port
	 * bit can/will cause a change in the data port.
	 */
	dp_changed = etr_eacr.e0 > eacr.e0 || etr_eacr.e1 > eacr.e1 ||
		(etr_eacr.dp ^ eacr.dp) != 0;
	etr_eacr = eacr;
	etr_setr(&etr_eacr);
	if (dp_changed)
		etr_tolec = get_clock();
}

/*
985
 * ETR work. In this function you'll find the main logic. In
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 * particular this is the only function that calls etr_update_eacr(),
 * it "controls" the etr control register.
 */
989
static void etr_work_fn(struct work_struct *work)
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{
	unsigned long long now;
	struct etr_eacr eacr;
	struct etr_aib aib;
	int sync_port;

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	/* prevent multiple execution. */
	mutex_lock(&etr_work_mutex);

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	/* Create working copy of etr_eacr. */
	eacr = etr_eacr;

	/* Check for the different events and their immediate effects. */
	eacr = etr_handle_events(eacr);

	/* Check if ETR is supposed to be active. */
	eacr.ea = eacr.p0 || eacr.p1;
	if (!eacr.ea) {
		/* Both ports offline. Reset everything. */
		eacr.dp = eacr.es = eacr.sl = 0;
1010
		on_each_cpu(disable_sync_clock, NULL, 1);
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		del_timer_sync(&etr_timer);
		etr_update_eacr(eacr);
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		goto out_unlock;
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	}

	/* Store aib to get the current ETR status word. */
	BUG_ON(etr_stetr(&aib) != 0);
	etr_port0.esw = etr_port1.esw = aib.esw;	/* Copy status word. */
	now = get_clock();

	/*
	 * Update the port information if the last stepping port change
	 * or data port change is older than 1.6 seconds.
	 */
	if (now >= etr_tolec + (1600000 << 12))
		eacr = etr_handle_update(&aib, eacr);

	/*
	 * Select ports to enable. The prefered synchronization mode is PPS.
	 * If a port can be enabled depends on a number of things:
	 * 1) The port needs to be online and uptodate. A port is not
	 *    disabled just because it is not uptodate, but it is only
	 *    enabled if it is uptodate.
	 * 2) The port needs to have the same mode (pps / etr).
	 * 3) The port needs to be usable -> etr_port_valid() == 1
	 * 4) To enable the second port the clock needs to be in sync.
	 * 5) If both ports are useable and are ETR ports, the network id
	 *    has to be the same.
	 * The eacr.sl bit is used to indicate etr mode vs. pps mode.
	 */
	if (eacr.p0 && aib.esw.psc0 == etr_lpsc_pps_mode) {
		eacr.sl = 0;
		eacr.e0 = 1;
		if (!etr_mode_is_pps(etr_eacr))
			eacr.es = 0;
		if (!eacr.es || !eacr.p1 || aib.esw.psc1 != etr_lpsc_pps_mode)
			eacr.e1 = 0;
		// FIXME: uptodate checks ?
		else if (etr_port0_uptodate && etr_port1_uptodate)
			eacr.e1 = 1;
		sync_port = (etr_port0_uptodate &&
			     etr_port_valid(&etr_port0, 0)) ? 0 : -1;
	} else if (eacr.p1 && aib.esw.psc1 == etr_lpsc_pps_mode) {
		eacr.sl = 0;
		eacr.e0 = 0;
		eacr.e1 = 1;
		if (!etr_mode_is_pps(etr_eacr))
			eacr.es = 0;
		sync_port = (etr_port1_uptodate &&
			     etr_port_valid(&etr_port1, 1)) ? 1 : -1;
	} else if (eacr.p0 && aib.esw.psc0 == etr_lpsc_operational_step) {
		eacr.sl = 1;
		eacr.e0 = 1;
		if (!etr_mode_is_etr(etr_eacr))
			eacr.es = 0;
		if (!eacr.es || !eacr.p1 ||
		    aib.esw.psc1 != etr_lpsc_operational_alt)
			eacr.e1 = 0;
		else if (etr_port0_uptodate && etr_port1_uptodate &&
			 etr_compare_network(&etr_port0, &etr_port1))
			eacr.e1 = 1;
		sync_port = (etr_port0_uptodate &&
			     etr_port_valid(&etr_port0, 0)) ? 0 : -1;
	} else if (eacr.p1 && aib.esw.psc1 == etr_lpsc_operational_step) {
		eacr.sl = 1;
		eacr.e0 = 0;
		eacr.e1 = 1;
		if (!etr_mode_is_etr(etr_eacr))
			eacr.es = 0;
		sync_port = (etr_port1_uptodate &&
			     etr_port_valid(&etr_port1, 1)) ? 1 : -1;
	} else {
		/* Both ports not usable. */
		eacr.es = eacr.sl = 0;
		sync_port = -1;
	}

	/*
	 * If the clock is in sync just update the eacr and return.
	 * If there is no valid sync port wait for a port update.
	 */
1092
	if (check_sync_clock() || sync_port < 0) {
M
Martin Schwidefsky 已提交
1093 1094
		etr_update_eacr(eacr);
		etr_set_tolec_timeout(now);
M
Martin Schwidefsky 已提交
1095
		goto out_unlock;
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Martin Schwidefsky 已提交
1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113
	}

	/*
	 * Prepare control register for clock syncing
	 * (reset data port bit, set sync check control.
	 */
	eacr.dp = 0;
	eacr.es = 1;

	/*
	 * Update eacr and try to synchronize the clock. If the update
	 * of eacr caused a stepping port switch (or if we have to
	 * assume that a stepping port switch has occured) or the
	 * clock syncing failed, reset the sync check control bit
	 * and set up a timer to try again after 0.5 seconds
	 */
	etr_update_eacr(eacr);
	if (now < etr_tolec + (1600000 << 12) ||
1114
	    etr_sync_clock_stop(&aib, sync_port) != 0) {
M
Martin Schwidefsky 已提交
1115 1116 1117 1118 1119 1120
		/* Sync failed. Try again in 1/2 second. */
		eacr.es = 0;
		etr_update_eacr(eacr);
		etr_set_sync_timeout();
	} else
		etr_set_tolec_timeout(now);
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1121 1122
out_unlock:
	mutex_unlock(&etr_work_mutex);
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1123 1124 1125 1126 1127 1128
}

/*
 * Sysfs interface functions
 */
static struct sysdev_class etr_sysclass = {
1129
	.name	= "etr",
M
Martin Schwidefsky 已提交
1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177
};

static struct sys_device etr_port0_dev = {
	.id	= 0,
	.cls	= &etr_sysclass,
};

static struct sys_device etr_port1_dev = {
	.id	= 1,
	.cls	= &etr_sysclass,
};

/*
 * ETR class attributes
 */
static ssize_t etr_stepping_port_show(struct sysdev_class *class, char *buf)
{
	return sprintf(buf, "%i\n", etr_port0.esw.p);
}

static SYSDEV_CLASS_ATTR(stepping_port, 0400, etr_stepping_port_show, NULL);

static ssize_t etr_stepping_mode_show(struct sysdev_class *class, char *buf)
{
	char *mode_str;

	if (etr_mode_is_pps(etr_eacr))
		mode_str = "pps";
	else if (etr_mode_is_etr(etr_eacr))
		mode_str = "etr";
	else
		mode_str = "local";
	return sprintf(buf, "%s\n", mode_str);
}

static SYSDEV_CLASS_ATTR(stepping_mode, 0400, etr_stepping_mode_show, NULL);

/*
 * ETR port attributes
 */
static inline struct etr_aib *etr_aib_from_dev(struct sys_device *dev)
{
	if (dev == &etr_port0_dev)
		return etr_port0_online ? &etr_port0 : NULL;
	else
		return etr_port1_online ? &etr_port1 : NULL;
}

1178 1179 1180
static ssize_t etr_online_show(struct sys_device *dev,
				struct sysdev_attribute *attr,
				char *buf)
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1181 1182 1183 1184 1185 1186 1187 1188
{
	unsigned int online;

	online = (dev == &etr_port0_dev) ? etr_port0_online : etr_port1_online;
	return sprintf(buf, "%i\n", online);
}

static ssize_t etr_online_store(struct sys_device *dev,
1189 1190
				struct sysdev_attribute *attr,
				const char *buf, size_t count)
M
Martin Schwidefsky 已提交
1191 1192 1193 1194 1195 1196
{
	unsigned int value;

	value = simple_strtoul(buf, NULL, 0);
	if (value != 0 && value != 1)
		return -EINVAL;
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Martin Schwidefsky 已提交
1197 1198
	if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags))
		return -EOPNOTSUPP;
1199
	mutex_lock(&clock_sync_mutex);
M
Martin Schwidefsky 已提交
1200 1201
	if (dev == &etr_port0_dev) {
		if (etr_port0_online == value)
1202
			goto out;	/* Nothing to do. */
M
Martin Schwidefsky 已提交
1203
		etr_port0_online = value;
1204 1205 1206 1207
		if (etr_port0_online && etr_port1_online)
			set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
		else
			clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
M
Martin Schwidefsky 已提交
1208
		set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
1209
		queue_work(time_sync_wq, &etr_work);
M
Martin Schwidefsky 已提交
1210 1211
	} else {
		if (etr_port1_online == value)
1212
			goto out;	/* Nothing to do. */
M
Martin Schwidefsky 已提交
1213
		etr_port1_online = value;
1214 1215 1216 1217
		if (etr_port0_online && etr_port1_online)
			set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
		else
			clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
M
Martin Schwidefsky 已提交
1218
		set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
1219
		queue_work(time_sync_wq, &etr_work);
M
Martin Schwidefsky 已提交
1220
	}
1221 1222
out:
	mutex_unlock(&clock_sync_mutex);
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Martin Schwidefsky 已提交
1223 1224 1225 1226 1227
	return count;
}

static SYSDEV_ATTR(online, 0600, etr_online_show, etr_online_store);

1228 1229 1230
static ssize_t etr_stepping_control_show(struct sys_device *dev,
					struct sysdev_attribute *attr,
					char *buf)
M
Martin Schwidefsky 已提交
1231 1232 1233 1234 1235 1236 1237
{
	return sprintf(buf, "%i\n", (dev == &etr_port0_dev) ?
		       etr_eacr.e0 : etr_eacr.e1);
}

static SYSDEV_ATTR(stepping_control, 0400, etr_stepping_control_show, NULL);

1238 1239
static ssize_t etr_mode_code_show(struct sys_device *dev,
				struct sysdev_attribute *attr, char *buf)
M
Martin Schwidefsky 已提交
1240 1241 1242 1243 1244 1245 1246 1247 1248 1249
{
	if (!etr_port0_online && !etr_port1_online)
		/* Status word is not uptodate if both ports are offline. */
		return -ENODATA;
	return sprintf(buf, "%i\n", (dev == &etr_port0_dev) ?
		       etr_port0.esw.psc0 : etr_port0.esw.psc1);
}

static SYSDEV_ATTR(state_code, 0400, etr_mode_code_show, NULL);

1250 1251
static ssize_t etr_untuned_show(struct sys_device *dev,
				struct sysdev_attribute *attr, char *buf)
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Martin Schwidefsky 已提交
1252 1253 1254 1255 1256 1257 1258 1259 1260 1261
{
	struct etr_aib *aib = etr_aib_from_dev(dev);

	if (!aib || !aib->slsw.v1)
		return -ENODATA;
	return sprintf(buf, "%i\n", aib->edf1.u);
}

static SYSDEV_ATTR(untuned, 0400, etr_untuned_show, NULL);

1262 1263
static ssize_t etr_network_id_show(struct sys_device *dev,
				struct sysdev_attribute *attr, char *buf)
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Martin Schwidefsky 已提交
1264 1265 1266 1267 1268 1269 1270 1271 1272 1273
{
	struct etr_aib *aib = etr_aib_from_dev(dev);

	if (!aib || !aib->slsw.v1)
		return -ENODATA;
	return sprintf(buf, "%i\n", aib->edf1.net_id);
}

static SYSDEV_ATTR(network, 0400, etr_network_id_show, NULL);

1274 1275
static ssize_t etr_id_show(struct sys_device *dev,
			struct sysdev_attribute *attr, char *buf)
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Martin Schwidefsky 已提交
1276 1277 1278 1279 1280 1281 1282 1283 1284 1285
{
	struct etr_aib *aib = etr_aib_from_dev(dev);

	if (!aib || !aib->slsw.v1)
		return -ENODATA;
	return sprintf(buf, "%i\n", aib->edf1.etr_id);
}

static SYSDEV_ATTR(id, 0400, etr_id_show, NULL);

1286 1287
static ssize_t etr_port_number_show(struct sys_device *dev,
			struct sysdev_attribute *attr, char *buf)
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Martin Schwidefsky 已提交
1288 1289 1290 1291 1292 1293 1294 1295 1296 1297
{
	struct etr_aib *aib = etr_aib_from_dev(dev);

	if (!aib || !aib->slsw.v1)
		return -ENODATA;
	return sprintf(buf, "%i\n", aib->edf1.etr_pn);
}

static SYSDEV_ATTR(port, 0400, etr_port_number_show, NULL);

1298 1299
static ssize_t etr_coupled_show(struct sys_device *dev,
			struct sysdev_attribute *attr, char *buf)
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Martin Schwidefsky 已提交
1300 1301 1302 1303 1304 1305 1306 1307 1308 1309
{
	struct etr_aib *aib = etr_aib_from_dev(dev);

	if (!aib || !aib->slsw.v3)
		return -ENODATA;
	return sprintf(buf, "%i\n", aib->edf3.c);
}

static SYSDEV_ATTR(coupled, 0400, etr_coupled_show, NULL);

1310 1311
static ssize_t etr_local_time_show(struct sys_device *dev,
			struct sysdev_attribute *attr, char *buf)
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Martin Schwidefsky 已提交
1312 1313 1314 1315 1316 1317 1318 1319 1320 1321
{
	struct etr_aib *aib = etr_aib_from_dev(dev);

	if (!aib || !aib->slsw.v3)
		return -ENODATA;
	return sprintf(buf, "%i\n", aib->edf3.blto);
}

static SYSDEV_ATTR(local_time, 0400, etr_local_time_show, NULL);

1322 1323
static ssize_t etr_utc_offset_show(struct sys_device *dev,
			struct sysdev_attribute *attr, char *buf)
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Martin Schwidefsky 已提交
1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409
{
	struct etr_aib *aib = etr_aib_from_dev(dev);

	if (!aib || !aib->slsw.v3)
		return -ENODATA;
	return sprintf(buf, "%i\n", aib->edf3.buo);
}

static SYSDEV_ATTR(utc_offset, 0400, etr_utc_offset_show, NULL);

static struct sysdev_attribute *etr_port_attributes[] = {
	&attr_online,
	&attr_stepping_control,
	&attr_state_code,
	&attr_untuned,
	&attr_network,
	&attr_id,
	&attr_port,
	&attr_coupled,
	&attr_local_time,
	&attr_utc_offset,
	NULL
};

static int __init etr_register_port(struct sys_device *dev)
{
	struct sysdev_attribute **attr;
	int rc;

	rc = sysdev_register(dev);
	if (rc)
		goto out;
	for (attr = etr_port_attributes; *attr; attr++) {
		rc = sysdev_create_file(dev, *attr);
		if (rc)
			goto out_unreg;
	}
	return 0;
out_unreg:
	for (; attr >= etr_port_attributes; attr--)
		sysdev_remove_file(dev, *attr);
	sysdev_unregister(dev);
out:
	return rc;
}

static void __init etr_unregister_port(struct sys_device *dev)
{
	struct sysdev_attribute **attr;

	for (attr = etr_port_attributes; *attr; attr++)
		sysdev_remove_file(dev, *attr);
	sysdev_unregister(dev);
}

static int __init etr_init_sysfs(void)
{
	int rc;

	rc = sysdev_class_register(&etr_sysclass);
	if (rc)
		goto out;
	rc = sysdev_class_create_file(&etr_sysclass, &attr_stepping_port);
	if (rc)
		goto out_unreg_class;
	rc = sysdev_class_create_file(&etr_sysclass, &attr_stepping_mode);
	if (rc)
		goto out_remove_stepping_port;
	rc = etr_register_port(&etr_port0_dev);
	if (rc)
		goto out_remove_stepping_mode;
	rc = etr_register_port(&etr_port1_dev);
	if (rc)
		goto out_remove_port0;
	return 0;

out_remove_port0:
	etr_unregister_port(&etr_port0_dev);
out_remove_stepping_mode:
	sysdev_class_remove_file(&etr_sysclass, &attr_stepping_mode);
out_remove_stepping_port:
	sysdev_class_remove_file(&etr_sysclass, &attr_stepping_port);
out_unreg_class:
	sysdev_class_unregister(&etr_sysclass);
out:
	return rc;
L
Linus Torvalds 已提交
1410 1411
}

M
Martin Schwidefsky 已提交
1412
device_initcall(etr_init_sysfs);
M
Martin Schwidefsky 已提交
1413 1414 1415 1416 1417 1418 1419 1420 1421

/*
 * Server Time Protocol (STP) code.
 */
static int stp_online;
static struct stp_sstpi stp_info;
static void *stp_page;

static void stp_work_fn(struct work_struct *work);
M
Martin Schwidefsky 已提交
1422
static DEFINE_MUTEX(stp_work_mutex);
M
Martin Schwidefsky 已提交
1423
static DECLARE_WORK(stp_work, stp_work_fn);
1424
static struct timer_list stp_timer;
M
Martin Schwidefsky 已提交
1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438

static int __init early_parse_stp(char *p)
{
	if (strncmp(p, "off", 3) == 0)
		stp_online = 0;
	else if (strncmp(p, "on", 2) == 0)
		stp_online = 1;
	return 0;
}
early_param("stp", early_parse_stp);

/*
 * Reset STP attachment.
 */
1439
static void __init stp_reset(void)
M
Martin Schwidefsky 已提交
1440 1441 1442
{
	int rc;

1443
	stp_page = (void *) get_zeroed_page(GFP_ATOMIC);
M
Martin Schwidefsky 已提交
1444
	rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000);
1445
	if (rc == 0)
M
Martin Schwidefsky 已提交
1446 1447
		set_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags);
	else if (stp_online) {
1448 1449
		pr_warning("The real or virtual hardware system does "
			   "not provide an STP interface\n");
1450
		free_page((unsigned long) stp_page);
M
Martin Schwidefsky 已提交
1451 1452 1453 1454 1455
		stp_page = NULL;
		stp_online = 0;
	}
}

1456 1457 1458 1459 1460
static void stp_timeout(unsigned long dummy)
{
	queue_work(time_sync_wq, &stp_work);
}

M
Martin Schwidefsky 已提交
1461 1462
static int __init stp_init(void)
{
1463 1464
	if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
		return 0;
1465
	setup_timer(&stp_timer, stp_timeout, 0UL);
1466 1467 1468 1469
	time_init_wq();
	if (!stp_online)
		return 0;
	queue_work(time_sync_wq, &stp_work);
M
Martin Schwidefsky 已提交
1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485
	return 0;
}

arch_initcall(stp_init);

/*
 * STP timing alert. There are three causes:
 * 1) timing status change
 * 2) link availability change
 * 3) time control parameter change
 * In all three cases we are only interested in the clock source state.
 * If a STP clock source is now available use it.
 */
static void stp_timing_alert(struct stp_irq_parm *intparm)
{
	if (intparm->tsc || intparm->lac || intparm->tcpc)
1486
		queue_work(time_sync_wq, &stp_work);
M
Martin Schwidefsky 已提交
1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497
}

/*
 * STP sync check machine check. This is called when the timing state
 * changes from the synchronized state to the unsynchronized state.
 * After a STP sync check the clock is not in sync. The machine check
 * is broadcasted to all cpus at the same time.
 */
void stp_sync_check(void)
{
	disable_sync_clock(NULL);
1498
	queue_work(time_sync_wq, &stp_work);
M
Martin Schwidefsky 已提交
1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509
}

/*
 * STP island condition machine check. This is called when an attached
 * server  attempts to communicate over an STP link and the servers
 * have matching CTN ids and have a valid stratum-1 configuration
 * but the configurations do not match.
 */
void stp_island_check(void)
{
	disable_sync_clock(NULL);
1510
	queue_work(time_sync_wq, &stp_work);
M
Martin Schwidefsky 已提交
1511 1512
}

1513 1514

static int stp_sync_clock(void *data)
M
Martin Schwidefsky 已提交
1515
{
1516
	static int first;
M
Martin Schwidefsky 已提交
1517
	unsigned long long old_clock, delta;
1518
	struct clock_sync_data *stp_sync;
M
Martin Schwidefsky 已提交
1519 1520
	int rc;

1521
	stp_sync = data;
M
Martin Schwidefsky 已提交
1522

1523 1524 1525 1526 1527
	if (xchg(&first, 1) == 1) {
		/* Slave */
		clock_sync_cpu(stp_sync);
		return 0;
	}
M
Martin Schwidefsky 已提交
1528

1529 1530 1531
	/* Wait until all other cpus entered the sync function. */
	while (atomic_read(&stp_sync->cpus) != 0)
		cpu_relax();
M
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1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551

	enable_sync_clock();

	rc = 0;
	if (stp_info.todoff[0] || stp_info.todoff[1] ||
	    stp_info.todoff[2] || stp_info.todoff[3] ||
	    stp_info.tmd != 2) {
		old_clock = get_clock();
		rc = chsc_sstpc(stp_page, STP_OP_SYNC, 0);
		if (rc == 0) {
			delta = adjust_time(old_clock, get_clock(), 0);
			fixup_clock_comparator(delta);
			rc = chsc_sstpi(stp_page, &stp_info,
					sizeof(struct stp_sstpi));
			if (rc == 0 && stp_info.tmd != 2)
				rc = -EAGAIN;
		}
	}
	if (rc) {
		disable_sync_clock(NULL);
1552
		stp_sync->in_sync = -EAGAIN;
M
Martin Schwidefsky 已提交
1553
	} else
1554 1555 1556 1557
		stp_sync->in_sync = 1;
	xchg(&first, 0);
	return 0;
}
M
Martin Schwidefsky 已提交
1558

1559 1560 1561 1562 1563 1564 1565 1566 1567
/*
 * STP work. Check for the STP state and take over the clock
 * synchronization if the STP clock source is usable.
 */
static void stp_work_fn(struct work_struct *work)
{
	struct clock_sync_data stp_sync;
	int rc;

M
Martin Schwidefsky 已提交
1568 1569 1570
	/* prevent multiple execution. */
	mutex_lock(&stp_work_mutex);

1571 1572
	if (!stp_online) {
		chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000);
1573
		del_timer_sync(&stp_timer);
M
Martin Schwidefsky 已提交
1574
		goto out_unlock;
1575 1576 1577 1578
	}

	rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xb0e0);
	if (rc)
M
Martin Schwidefsky 已提交
1579
		goto out_unlock;
1580 1581 1582

	rc = chsc_sstpi(stp_page, &stp_info, sizeof(struct stp_sstpi));
	if (rc || stp_info.c == 0)
M
Martin Schwidefsky 已提交
1583
		goto out_unlock;
1584

1585 1586 1587 1588
	/* Skip synchronization if the clock is already in sync. */
	if (check_sync_clock())
		goto out_unlock;

1589 1590 1591 1592 1593
	memset(&stp_sync, 0, sizeof(stp_sync));
	get_online_cpus();
	atomic_set(&stp_sync.cpus, num_online_cpus() - 1);
	stop_machine(stp_sync_clock, &stp_sync, &cpu_online_map);
	put_online_cpus();
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Martin Schwidefsky 已提交
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	if (!check_sync_clock())
		/*
		 * There is a usable clock but the synchonization failed.
		 * Retry after a second.
		 */
		mod_timer(&stp_timer, jiffies + HZ);

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out_unlock:
	mutex_unlock(&stp_work_mutex);
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}

/*
 * STP class sysfs interface functions
 */
static struct sysdev_class stp_sysclass = {
	.name	= "stp",
};

static ssize_t stp_ctn_id_show(struct sysdev_class *class, char *buf)
{
	if (!stp_online)
		return -ENODATA;
	return sprintf(buf, "%016llx\n",
		       *(unsigned long long *) stp_info.ctnid);
}

static SYSDEV_CLASS_ATTR(ctn_id, 0400, stp_ctn_id_show, NULL);

static ssize_t stp_ctn_type_show(struct sysdev_class *class, char *buf)
{
	if (!stp_online)
		return -ENODATA;
	return sprintf(buf, "%i\n", stp_info.ctn);
}

static SYSDEV_CLASS_ATTR(ctn_type, 0400, stp_ctn_type_show, NULL);

static ssize_t stp_dst_offset_show(struct sysdev_class *class, char *buf)
{
	if (!stp_online || !(stp_info.vbits & 0x2000))
		return -ENODATA;
	return sprintf(buf, "%i\n", (int)(s16) stp_info.dsto);
}

static SYSDEV_CLASS_ATTR(dst_offset, 0400, stp_dst_offset_show, NULL);

static ssize_t stp_leap_seconds_show(struct sysdev_class *class, char *buf)
{
	if (!stp_online || !(stp_info.vbits & 0x8000))
		return -ENODATA;
	return sprintf(buf, "%i\n", (int)(s16) stp_info.leaps);
}

static SYSDEV_CLASS_ATTR(leap_seconds, 0400, stp_leap_seconds_show, NULL);

static ssize_t stp_stratum_show(struct sysdev_class *class, char *buf)
{
	if (!stp_online)
		return -ENODATA;
	return sprintf(buf, "%i\n", (int)(s16) stp_info.stratum);
}

static SYSDEV_CLASS_ATTR(stratum, 0400, stp_stratum_show, NULL);

static ssize_t stp_time_offset_show(struct sysdev_class *class, char *buf)
{
	if (!stp_online || !(stp_info.vbits & 0x0800))
		return -ENODATA;
	return sprintf(buf, "%i\n", (int) stp_info.tto);
}

static SYSDEV_CLASS_ATTR(time_offset, 0400, stp_time_offset_show, NULL);

static ssize_t stp_time_zone_offset_show(struct sysdev_class *class, char *buf)
{
	if (!stp_online || !(stp_info.vbits & 0x4000))
		return -ENODATA;
	return sprintf(buf, "%i\n", (int)(s16) stp_info.tzo);
}

static SYSDEV_CLASS_ATTR(time_zone_offset, 0400,
			 stp_time_zone_offset_show, NULL);

static ssize_t stp_timing_mode_show(struct sysdev_class *class, char *buf)
{
	if (!stp_online)
		return -ENODATA;
	return sprintf(buf, "%i\n", stp_info.tmd);
}

static SYSDEV_CLASS_ATTR(timing_mode, 0400, stp_timing_mode_show, NULL);

static ssize_t stp_timing_state_show(struct sysdev_class *class, char *buf)
{
	if (!stp_online)
		return -ENODATA;
	return sprintf(buf, "%i\n", stp_info.tst);
}

static SYSDEV_CLASS_ATTR(timing_state, 0400, stp_timing_state_show, NULL);

static ssize_t stp_online_show(struct sysdev_class *class, char *buf)
{
	return sprintf(buf, "%i\n", stp_online);
}

static ssize_t stp_online_store(struct sysdev_class *class,
				const char *buf, size_t count)
{
	unsigned int value;

	value = simple_strtoul(buf, NULL, 0);
	if (value != 0 && value != 1)
		return -EINVAL;
	if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
		return -EOPNOTSUPP;
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	mutex_lock(&clock_sync_mutex);
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Martin Schwidefsky 已提交
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	stp_online = value;
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	if (stp_online)
		set_bit(CLOCK_SYNC_STP, &clock_sync_flags);
	else
		clear_bit(CLOCK_SYNC_STP, &clock_sync_flags);
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	queue_work(time_sync_wq, &stp_work);
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	mutex_unlock(&clock_sync_mutex);
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	return count;
}

/*
 * Can't use SYSDEV_CLASS_ATTR because the attribute should be named
 * stp/online but attr_online already exists in this file ..
 */
static struct sysdev_class_attribute attr_stp_online = {
	.attr = { .name = "online", .mode = 0600 },
	.show	= stp_online_show,
	.store	= stp_online_store,
};

static struct sysdev_class_attribute *stp_attributes[] = {
	&attr_ctn_id,
	&attr_ctn_type,
	&attr_dst_offset,
	&attr_leap_seconds,
	&attr_stp_online,
	&attr_stratum,
	&attr_time_offset,
	&attr_time_zone_offset,
	&attr_timing_mode,
	&attr_timing_state,
	NULL
};

static int __init stp_init_sysfs(void)
{
	struct sysdev_class_attribute **attr;
	int rc;

	rc = sysdev_class_register(&stp_sysclass);
	if (rc)
		goto out;
	for (attr = stp_attributes; *attr; attr++) {
		rc = sysdev_class_create_file(&stp_sysclass, *attr);
		if (rc)
			goto out_unreg;
	}
	return 0;
out_unreg:
	for (; attr >= stp_attributes; attr--)
		sysdev_class_remove_file(&stp_sysclass, *attr);
	sysdev_class_unregister(&stp_sysclass);
out:
	return rc;
}

device_initcall(stp_init_sysfs);