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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Time of day based timer functions.
4 *
5 * S390 version
6 * Copyright IBM Corp. 1999, 2008
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
15#define KMSG_COMPONENT "time"
16#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
17
18#include <linux/kernel_stat.h>
19#include <linux/errno.h>
20#include <linux/export.h>
21#include <linux/sched.h>
22#include <linux/sched/clock.h>
23#include <linux/kernel.h>
24#include <linux/param.h>
25#include <linux/string.h>
26#include <linux/mm.h>
27#include <linux/interrupt.h>
28#include <linux/cpu.h>
29#include <linux/stop_machine.h>
30#include <linux/time.h>
31#include <linux/device.h>
32#include <linux/delay.h>
33#include <linux/init.h>
34#include <linux/smp.h>
35#include <linux/types.h>
36#include <linux/profile.h>
37#include <linux/timex.h>
38#include <linux/notifier.h>
39#include <linux/clockchips.h>
40#include <linux/gfp.h>
41#include <linux/kprobes.h>
42#include <linux/uaccess.h>
43#include <vdso/vsyscall.h>
44#include <vdso/clocksource.h>
45#include <vdso/helpers.h>
46#include <asm/facility.h>
47#include <asm/delay.h>
48#include <asm/div64.h>
49#include <asm/vdso.h>
50#include <asm/irq.h>
51#include <asm/irq_regs.h>
52#include <asm/vtimer.h>
53#include <asm/stp.h>
54#include <asm/cio.h>
55#include "entry.h"
56
57union tod_clock tod_clock_base __section(".data");
58EXPORT_SYMBOL_GPL(tod_clock_base);
59
60u64 clock_comparator_max = -1ULL;
61EXPORT_SYMBOL_GPL(clock_comparator_max);
62
63static DEFINE_PER_CPU(struct clock_event_device, comparators);
64
65ATOMIC_NOTIFIER_HEAD(s390_epoch_delta_notifier);
66EXPORT_SYMBOL(s390_epoch_delta_notifier);
67
68unsigned char ptff_function_mask[16];
69
70static unsigned long lpar_offset;
71static unsigned long initial_leap_seconds;
72static unsigned long tod_steering_end;
73static long tod_steering_delta;
74
75/*
76 * Get time offsets with PTFF
77 */
78void __init time_early_init(void)
79{
80 struct ptff_qto qto;
81 struct ptff_qui qui;
82 int cs;
83
84 /* Initialize TOD steering parameters */
85 tod_steering_end = tod_clock_base.tod;
86 for (cs = 0; cs < CS_BASES; cs++)
87 vdso_data[cs].arch_data.tod_steering_end = tod_steering_end;
88
89 if (!test_facility(28))
90 return;
91
92 ptff(&ptff_function_mask, sizeof(ptff_function_mask), PTFF_QAF);
93
94 /* get LPAR offset */
95 if (ptff_query(PTFF_QTO) && ptff(&qto, sizeof(qto), PTFF_QTO) == 0)
96 lpar_offset = qto.tod_epoch_difference;
97
98 /* get initial leap seconds */
99 if (ptff_query(PTFF_QUI) && ptff(&qui, sizeof(qui), PTFF_QUI) == 0)
100 initial_leap_seconds = (unsigned long)
101 ((long) qui.old_leap * 4096000000L);
102}
103
104unsigned long long noinstr sched_clock_noinstr(void)
105{
106 return tod_to_ns(__get_tod_clock_monotonic());
107}
108
109/*
110 * Scheduler clock - returns current time in nanosec units.
111 */
112unsigned long long notrace sched_clock(void)
113{
114 return tod_to_ns(get_tod_clock_monotonic());
115}
116NOKPROBE_SYMBOL(sched_clock);
117
118static void ext_to_timespec64(union tod_clock *clk, struct timespec64 *xt)
119{
120 unsigned long rem, sec, nsec;
121
122 sec = clk->us;
123 rem = do_div(sec, 1000000);
124 nsec = ((clk->sus + (rem << 12)) * 125) >> 9;
125 xt->tv_sec = sec;
126 xt->tv_nsec = nsec;
127}
128
129void clock_comparator_work(void)
130{
131 struct clock_event_device *cd;
132
133 get_lowcore()->clock_comparator = clock_comparator_max;
134 cd = this_cpu_ptr(&comparators);
135 cd->event_handler(cd);
136}
137
138static int s390_next_event(unsigned long delta,
139 struct clock_event_device *evt)
140{
141 get_lowcore()->clock_comparator = get_tod_clock() + delta;
142 set_clock_comparator(get_lowcore()->clock_comparator);
143 return 0;
144}
145
146/*
147 * Set up lowcore and control register of the current cpu to
148 * enable TOD clock and clock comparator interrupts.
149 */
150void init_cpu_timer(void)
151{
152 struct clock_event_device *cd;
153 int cpu;
154
155 get_lowcore()->clock_comparator = clock_comparator_max;
156 set_clock_comparator(get_lowcore()->clock_comparator);
157
158 cpu = smp_processor_id();
159 cd = &per_cpu(comparators, cpu);
160 cd->name = "comparator";
161 cd->features = CLOCK_EVT_FEAT_ONESHOT;
162 cd->mult = 16777;
163 cd->shift = 12;
164 cd->min_delta_ns = 1;
165 cd->min_delta_ticks = 1;
166 cd->max_delta_ns = LONG_MAX;
167 cd->max_delta_ticks = ULONG_MAX;
168 cd->rating = 400;
169 cd->cpumask = cpumask_of(cpu);
170 cd->set_next_event = s390_next_event;
171
172 clockevents_register_device(cd);
173
174 /* Enable clock comparator timer interrupt. */
175 local_ctl_set_bit(0, CR0_CLOCK_COMPARATOR_SUBMASK_BIT);
176
177 /* Always allow the timing alert external interrupt. */
178 local_ctl_set_bit(0, CR0_ETR_SUBMASK_BIT);
179}
180
181static void clock_comparator_interrupt(struct ext_code ext_code,
182 unsigned int param32,
183 unsigned long param64)
184{
185 inc_irq_stat(IRQEXT_CLK);
186 if (get_lowcore()->clock_comparator == clock_comparator_max)
187 set_clock_comparator(get_lowcore()->clock_comparator);
188}
189
190static void stp_timing_alert(struct stp_irq_parm *);
191
192static void timing_alert_interrupt(struct ext_code ext_code,
193 unsigned int param32, unsigned long param64)
194{
195 inc_irq_stat(IRQEXT_TLA);
196 if (param32 & 0x00038000)
197 stp_timing_alert((struct stp_irq_parm *) ¶m32);
198}
199
200static void stp_reset(void);
201
202void read_persistent_clock64(struct timespec64 *ts)
203{
204 union tod_clock clk;
205 u64 delta;
206
207 delta = initial_leap_seconds + TOD_UNIX_EPOCH;
208 store_tod_clock_ext(&clk);
209 clk.eitod -= delta;
210 ext_to_timespec64(&clk, ts);
211}
212
213void __init read_persistent_wall_and_boot_offset(struct timespec64 *wall_time,
214 struct timespec64 *boot_offset)
215{
216 struct timespec64 boot_time;
217 union tod_clock clk;
218 u64 delta;
219
220 delta = initial_leap_seconds + TOD_UNIX_EPOCH;
221 clk = tod_clock_base;
222 clk.eitod -= delta;
223 ext_to_timespec64(&clk, &boot_time);
224
225 read_persistent_clock64(wall_time);
226 *boot_offset = timespec64_sub(*wall_time, boot_time);
227}
228
229static u64 read_tod_clock(struct clocksource *cs)
230{
231 unsigned long now, adj;
232
233 preempt_disable(); /* protect from changes to steering parameters */
234 now = get_tod_clock();
235 adj = tod_steering_end - now;
236 if (unlikely((s64) adj > 0))
237 /*
238 * manually steer by 1 cycle every 2^16 cycles. This
239 * corresponds to shifting the tod delta by 15. 1s is
240 * therefore steered in ~9h. The adjust will decrease
241 * over time, until it finally reaches 0.
242 */
243 now += (tod_steering_delta < 0) ? (adj >> 15) : -(adj >> 15);
244 preempt_enable();
245 return now;
246}
247
248static struct clocksource clocksource_tod = {
249 .name = "tod",
250 .rating = 400,
251 .read = read_tod_clock,
252 .mask = CLOCKSOURCE_MASK(64),
253 .mult = 4096000,
254 .shift = 24,
255 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
256 .vdso_clock_mode = VDSO_CLOCKMODE_TOD,
257 .id = CSID_S390_TOD,
258};
259
260struct clocksource * __init clocksource_default_clock(void)
261{
262 return &clocksource_tod;
263}
264
265/*
266 * Initialize the TOD clock and the CPU timer of
267 * the boot cpu.
268 */
269void __init time_init(void)
270{
271 /* Reset time synchronization interfaces. */
272 stp_reset();
273
274 /* request the clock comparator external interrupt */
275 if (register_external_irq(EXT_IRQ_CLK_COMP, clock_comparator_interrupt))
276 panic("Couldn't request external interrupt 0x1004");
277
278 /* request the timing alert external interrupt */
279 if (register_external_irq(EXT_IRQ_TIMING_ALERT, timing_alert_interrupt))
280 panic("Couldn't request external interrupt 0x1406");
281
282 if (__clocksource_register(&clocksource_tod) != 0)
283 panic("Could not register TOD clock source");
284
285 /* Enable TOD clock interrupts on the boot cpu. */
286 init_cpu_timer();
287
288 /* Enable cpu timer interrupts on the boot cpu. */
289 vtime_init();
290}
291
292static DEFINE_PER_CPU(atomic_t, clock_sync_word);
293static DEFINE_MUTEX(stp_mutex);
294static unsigned long clock_sync_flags;
295
296#define CLOCK_SYNC_HAS_STP 0
297#define CLOCK_SYNC_STP 1
298#define CLOCK_SYNC_STPINFO_VALID 2
299
300/*
301 * The get_clock function for the physical clock. It will get the current
302 * TOD clock, subtract the LPAR offset and write the result to *clock.
303 * The function returns 0 if the clock is in sync with the external time
304 * source. If the clock mode is local it will return -EOPNOTSUPP and
305 * -EAGAIN if the clock is not in sync with the external reference.
306 */
307int get_phys_clock(unsigned long *clock)
308{
309 atomic_t *sw_ptr;
310 unsigned int sw0, sw1;
311
312 sw_ptr = &get_cpu_var(clock_sync_word);
313 sw0 = atomic_read(sw_ptr);
314 *clock = get_tod_clock() - lpar_offset;
315 sw1 = atomic_read(sw_ptr);
316 put_cpu_var(clock_sync_word);
317 if (sw0 == sw1 && (sw0 & 0x80000000U))
318 /* Success: time is in sync. */
319 return 0;
320 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
321 return -EOPNOTSUPP;
322 if (!test_bit(CLOCK_SYNC_STP, &clock_sync_flags))
323 return -EACCES;
324 return -EAGAIN;
325}
326EXPORT_SYMBOL(get_phys_clock);
327
328/*
329 * Make get_phys_clock() return -EAGAIN.
330 */
331static void disable_sync_clock(void *dummy)
332{
333 atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
334 /*
335 * Clear the in-sync bit 2^31. All get_phys_clock calls will
336 * fail until the sync bit is turned back on. In addition
337 * increase the "sequence" counter to avoid the race of an
338 * stp event and the complete recovery against get_phys_clock.
339 */
340 atomic_andnot(0x80000000, sw_ptr);
341 atomic_inc(sw_ptr);
342}
343
344/*
345 * Make get_phys_clock() return 0 again.
346 * Needs to be called from a context disabled for preemption.
347 */
348static void enable_sync_clock(void)
349{
350 atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
351 atomic_or(0x80000000, sw_ptr);
352}
353
354/*
355 * Function to check if the clock is in sync.
356 */
357static inline int check_sync_clock(void)
358{
359 atomic_t *sw_ptr;
360 int rc;
361
362 sw_ptr = &get_cpu_var(clock_sync_word);
363 rc = (atomic_read(sw_ptr) & 0x80000000U) != 0;
364 put_cpu_var(clock_sync_word);
365 return rc;
366}
367
368/*
369 * Apply clock delta to the global data structures.
370 * This is called once on the CPU that performed the clock sync.
371 */
372static void clock_sync_global(long delta)
373{
374 unsigned long now, adj;
375 struct ptff_qto qto;
376 int cs;
377
378 /* Fixup the monotonic sched clock. */
379 tod_clock_base.eitod += delta;
380 /* Adjust TOD steering parameters. */
381 now = get_tod_clock();
382 adj = tod_steering_end - now;
383 if (unlikely((s64) adj >= 0))
384 /* Calculate how much of the old adjustment is left. */
385 tod_steering_delta = (tod_steering_delta < 0) ?
386 -(adj >> 15) : (adj >> 15);
387 tod_steering_delta += delta;
388 if ((abs(tod_steering_delta) >> 48) != 0)
389 panic("TOD clock sync offset %li is too large to drift\n",
390 tod_steering_delta);
391 tod_steering_end = now + (abs(tod_steering_delta) << 15);
392 for (cs = 0; cs < CS_BASES; cs++) {
393 vdso_data[cs].arch_data.tod_steering_end = tod_steering_end;
394 vdso_data[cs].arch_data.tod_steering_delta = tod_steering_delta;
395 }
396
397 /* Update LPAR offset. */
398 if (ptff_query(PTFF_QTO) && ptff(&qto, sizeof(qto), PTFF_QTO) == 0)
399 lpar_offset = qto.tod_epoch_difference;
400 /* Call the TOD clock change notifier. */
401 atomic_notifier_call_chain(&s390_epoch_delta_notifier, 0, &delta);
402}
403
404/*
405 * Apply clock delta to the per-CPU data structures of this CPU.
406 * This is called for each online CPU after the call to clock_sync_global.
407 */
408static void clock_sync_local(long delta)
409{
410 /* Add the delta to the clock comparator. */
411 if (get_lowcore()->clock_comparator != clock_comparator_max) {
412 get_lowcore()->clock_comparator += delta;
413 set_clock_comparator(get_lowcore()->clock_comparator);
414 }
415 /* Adjust the last_update_clock time-stamp. */
416 get_lowcore()->last_update_clock += delta;
417}
418
419/* Single threaded workqueue used for stp sync events */
420static struct workqueue_struct *time_sync_wq;
421
422static void __init time_init_wq(void)
423{
424 if (time_sync_wq)
425 return;
426 time_sync_wq = create_singlethread_workqueue("timesync");
427}
428
429struct clock_sync_data {
430 atomic_t cpus;
431 int in_sync;
432 long clock_delta;
433};
434
435/*
436 * Server Time Protocol (STP) code.
437 */
438static bool stp_online;
439static struct stp_sstpi stp_info;
440static void *stp_page;
441
442static void stp_work_fn(struct work_struct *work);
443static DECLARE_WORK(stp_work, stp_work_fn);
444static struct timer_list stp_timer;
445
446static int __init early_parse_stp(char *p)
447{
448 return kstrtobool(p, &stp_online);
449}
450early_param("stp", early_parse_stp);
451
452/*
453 * Reset STP attachment.
454 */
455static void __init stp_reset(void)
456{
457 int rc;
458
459 stp_page = (void *) get_zeroed_page(GFP_ATOMIC);
460 rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000, NULL);
461 if (rc == 0)
462 set_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags);
463 else if (stp_online) {
464 pr_warn("The real or virtual hardware system does not provide an STP interface\n");
465 free_page((unsigned long) stp_page);
466 stp_page = NULL;
467 stp_online = false;
468 }
469}
470
471bool stp_enabled(void)
472{
473 return test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags) && stp_online;
474}
475EXPORT_SYMBOL(stp_enabled);
476
477static void stp_timeout(struct timer_list *unused)
478{
479 queue_work(time_sync_wq, &stp_work);
480}
481
482static int __init stp_init(void)
483{
484 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
485 return 0;
486 timer_setup(&stp_timer, stp_timeout, 0);
487 time_init_wq();
488 if (!stp_online)
489 return 0;
490 queue_work(time_sync_wq, &stp_work);
491 return 0;
492}
493
494arch_initcall(stp_init);
495
496/*
497 * STP timing alert. There are three causes:
498 * 1) timing status change
499 * 2) link availability change
500 * 3) time control parameter change
501 * In all three cases we are only interested in the clock source state.
502 * If a STP clock source is now available use it.
503 */
504static void stp_timing_alert(struct stp_irq_parm *intparm)
505{
506 if (intparm->tsc || intparm->lac || intparm->tcpc)
507 queue_work(time_sync_wq, &stp_work);
508}
509
510/*
511 * STP sync check machine check. This is called when the timing state
512 * changes from the synchronized state to the unsynchronized state.
513 * After a STP sync check the clock is not in sync. The machine check
514 * is broadcasted to all cpus at the same time.
515 */
516int stp_sync_check(void)
517{
518 disable_sync_clock(NULL);
519 return 1;
520}
521
522/*
523 * STP island condition machine check. This is called when an attached
524 * server attempts to communicate over an STP link and the servers
525 * have matching CTN ids and have a valid stratum-1 configuration
526 * but the configurations do not match.
527 */
528int stp_island_check(void)
529{
530 disable_sync_clock(NULL);
531 return 1;
532}
533
534void stp_queue_work(void)
535{
536 queue_work(time_sync_wq, &stp_work);
537}
538
539static int __store_stpinfo(void)
540{
541 int rc = chsc_sstpi(stp_page, &stp_info, sizeof(struct stp_sstpi));
542
543 if (rc)
544 clear_bit(CLOCK_SYNC_STPINFO_VALID, &clock_sync_flags);
545 else
546 set_bit(CLOCK_SYNC_STPINFO_VALID, &clock_sync_flags);
547 return rc;
548}
549
550static int stpinfo_valid(void)
551{
552 return stp_online && test_bit(CLOCK_SYNC_STPINFO_VALID, &clock_sync_flags);
553}
554
555static int stp_sync_clock(void *data)
556{
557 struct clock_sync_data *sync = data;
558 long clock_delta, flags;
559 static int first;
560 int rc;
561
562 enable_sync_clock();
563 if (xchg(&first, 1) == 0) {
564 /* Wait until all other cpus entered the sync function. */
565 while (atomic_read(&sync->cpus) != 0)
566 cpu_relax();
567 rc = 0;
568 if (stp_info.todoff || stp_info.tmd != 2) {
569 flags = vdso_update_begin();
570 rc = chsc_sstpc(stp_page, STP_OP_SYNC, 0,
571 &clock_delta);
572 if (rc == 0) {
573 sync->clock_delta = clock_delta;
574 clock_sync_global(clock_delta);
575 rc = __store_stpinfo();
576 if (rc == 0 && stp_info.tmd != 2)
577 rc = -EAGAIN;
578 }
579 vdso_update_end(flags);
580 }
581 sync->in_sync = rc ? -EAGAIN : 1;
582 xchg(&first, 0);
583 } else {
584 /* Slave */
585 atomic_dec(&sync->cpus);
586 /* Wait for in_sync to be set. */
587 while (READ_ONCE(sync->in_sync) == 0)
588 __udelay(1);
589 }
590 if (sync->in_sync != 1)
591 /* Didn't work. Clear per-cpu in sync bit again. */
592 disable_sync_clock(NULL);
593 /* Apply clock delta to per-CPU fields of this CPU. */
594 clock_sync_local(sync->clock_delta);
595
596 return 0;
597}
598
599static int stp_clear_leap(void)
600{
601 struct __kernel_timex txc;
602 int ret;
603
604 memset(&txc, 0, sizeof(txc));
605
606 ret = do_adjtimex(&txc);
607 if (ret < 0)
608 return ret;
609
610 txc.modes = ADJ_STATUS;
611 txc.status &= ~(STA_INS|STA_DEL);
612 return do_adjtimex(&txc);
613}
614
615static void stp_check_leap(void)
616{
617 struct stp_stzi stzi;
618 struct stp_lsoib *lsoib = &stzi.lsoib;
619 struct __kernel_timex txc;
620 int64_t timediff;
621 int leapdiff, ret;
622
623 if (!stp_info.lu || !check_sync_clock()) {
624 /*
625 * Either a scheduled leap second was removed by the operator,
626 * or STP is out of sync. In both cases, clear the leap second
627 * kernel flags.
628 */
629 if (stp_clear_leap() < 0)
630 pr_err("failed to clear leap second flags\n");
631 return;
632 }
633
634 if (chsc_stzi(stp_page, &stzi, sizeof(stzi))) {
635 pr_err("stzi failed\n");
636 return;
637 }
638
639 timediff = tod_to_ns(lsoib->nlsout - get_tod_clock()) / NSEC_PER_SEC;
640 leapdiff = lsoib->nlso - lsoib->also;
641
642 if (leapdiff != 1 && leapdiff != -1) {
643 pr_err("Cannot schedule %d leap seconds\n", leapdiff);
644 return;
645 }
646
647 if (timediff < 0) {
648 if (stp_clear_leap() < 0)
649 pr_err("failed to clear leap second flags\n");
650 } else if (timediff < 7200) {
651 memset(&txc, 0, sizeof(txc));
652 ret = do_adjtimex(&txc);
653 if (ret < 0)
654 return;
655
656 txc.modes = ADJ_STATUS;
657 if (leapdiff > 0)
658 txc.status |= STA_INS;
659 else
660 txc.status |= STA_DEL;
661 ret = do_adjtimex(&txc);
662 if (ret < 0)
663 pr_err("failed to set leap second flags\n");
664 /* arm Timer to clear leap second flags */
665 mod_timer(&stp_timer, jiffies + msecs_to_jiffies(14400 * MSEC_PER_SEC));
666 } else {
667 /* The day the leap second is scheduled for hasn't been reached. Retry
668 * in one hour.
669 */
670 mod_timer(&stp_timer, jiffies + msecs_to_jiffies(3600 * MSEC_PER_SEC));
671 }
672}
673
674/*
675 * STP work. Check for the STP state and take over the clock
676 * synchronization if the STP clock source is usable.
677 */
678static void stp_work_fn(struct work_struct *work)
679{
680 struct clock_sync_data stp_sync;
681 int rc;
682
683 /* prevent multiple execution. */
684 mutex_lock(&stp_mutex);
685
686 if (!stp_online) {
687 chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000, NULL);
688 del_timer_sync(&stp_timer);
689 goto out_unlock;
690 }
691
692 rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xf0e0, NULL);
693 if (rc)
694 goto out_unlock;
695
696 rc = __store_stpinfo();
697 if (rc || stp_info.c == 0)
698 goto out_unlock;
699
700 /* Skip synchronization if the clock is already in sync. */
701 if (!check_sync_clock()) {
702 memset(&stp_sync, 0, sizeof(stp_sync));
703 cpus_read_lock();
704 atomic_set(&stp_sync.cpus, num_online_cpus() - 1);
705 stop_machine_cpuslocked(stp_sync_clock, &stp_sync, cpu_online_mask);
706 cpus_read_unlock();
707 }
708
709 if (!check_sync_clock())
710 /*
711 * There is a usable clock but the synchronization failed.
712 * Retry after a second.
713 */
714 mod_timer(&stp_timer, jiffies + msecs_to_jiffies(MSEC_PER_SEC));
715 else if (stp_info.lu)
716 stp_check_leap();
717
718out_unlock:
719 mutex_unlock(&stp_mutex);
720}
721
722/*
723 * STP subsys sysfs interface functions
724 */
725static const struct bus_type stp_subsys = {
726 .name = "stp",
727 .dev_name = "stp",
728};
729
730static ssize_t ctn_id_show(struct device *dev,
731 struct device_attribute *attr,
732 char *buf)
733{
734 ssize_t ret = -ENODATA;
735
736 mutex_lock(&stp_mutex);
737 if (stpinfo_valid())
738 ret = sysfs_emit(buf, "%016lx\n",
739 *(unsigned long *)stp_info.ctnid);
740 mutex_unlock(&stp_mutex);
741 return ret;
742}
743
744static DEVICE_ATTR_RO(ctn_id);
745
746static ssize_t ctn_type_show(struct device *dev,
747 struct device_attribute *attr,
748 char *buf)
749{
750 ssize_t ret = -ENODATA;
751
752 mutex_lock(&stp_mutex);
753 if (stpinfo_valid())
754 ret = sysfs_emit(buf, "%i\n", stp_info.ctn);
755 mutex_unlock(&stp_mutex);
756 return ret;
757}
758
759static DEVICE_ATTR_RO(ctn_type);
760
761static ssize_t dst_offset_show(struct device *dev,
762 struct device_attribute *attr,
763 char *buf)
764{
765 ssize_t ret = -ENODATA;
766
767 mutex_lock(&stp_mutex);
768 if (stpinfo_valid() && (stp_info.vbits & 0x2000))
769 ret = sysfs_emit(buf, "%i\n", (int)(s16)stp_info.dsto);
770 mutex_unlock(&stp_mutex);
771 return ret;
772}
773
774static DEVICE_ATTR_RO(dst_offset);
775
776static ssize_t leap_seconds_show(struct device *dev,
777 struct device_attribute *attr,
778 char *buf)
779{
780 ssize_t ret = -ENODATA;
781
782 mutex_lock(&stp_mutex);
783 if (stpinfo_valid() && (stp_info.vbits & 0x8000))
784 ret = sysfs_emit(buf, "%i\n", (int)(s16)stp_info.leaps);
785 mutex_unlock(&stp_mutex);
786 return ret;
787}
788
789static DEVICE_ATTR_RO(leap_seconds);
790
791static ssize_t leap_seconds_scheduled_show(struct device *dev,
792 struct device_attribute *attr,
793 char *buf)
794{
795 struct stp_stzi stzi;
796 ssize_t ret;
797
798 mutex_lock(&stp_mutex);
799 if (!stpinfo_valid() || !(stp_info.vbits & 0x8000) || !stp_info.lu) {
800 mutex_unlock(&stp_mutex);
801 return -ENODATA;
802 }
803
804 ret = chsc_stzi(stp_page, &stzi, sizeof(stzi));
805 mutex_unlock(&stp_mutex);
806 if (ret < 0)
807 return ret;
808
809 if (!stzi.lsoib.p)
810 return sysfs_emit(buf, "0,0\n");
811
812 return sysfs_emit(buf, "%lu,%d\n",
813 tod_to_ns(stzi.lsoib.nlsout - TOD_UNIX_EPOCH) / NSEC_PER_SEC,
814 stzi.lsoib.nlso - stzi.lsoib.also);
815}
816
817static DEVICE_ATTR_RO(leap_seconds_scheduled);
818
819static ssize_t stratum_show(struct device *dev,
820 struct device_attribute *attr,
821 char *buf)
822{
823 ssize_t ret = -ENODATA;
824
825 mutex_lock(&stp_mutex);
826 if (stpinfo_valid())
827 ret = sysfs_emit(buf, "%i\n", (int)(s16)stp_info.stratum);
828 mutex_unlock(&stp_mutex);
829 return ret;
830}
831
832static DEVICE_ATTR_RO(stratum);
833
834static ssize_t time_offset_show(struct device *dev,
835 struct device_attribute *attr,
836 char *buf)
837{
838 ssize_t ret = -ENODATA;
839
840 mutex_lock(&stp_mutex);
841 if (stpinfo_valid() && (stp_info.vbits & 0x0800))
842 ret = sysfs_emit(buf, "%i\n", (int)stp_info.tto);
843 mutex_unlock(&stp_mutex);
844 return ret;
845}
846
847static DEVICE_ATTR_RO(time_offset);
848
849static ssize_t time_zone_offset_show(struct device *dev,
850 struct device_attribute *attr,
851 char *buf)
852{
853 ssize_t ret = -ENODATA;
854
855 mutex_lock(&stp_mutex);
856 if (stpinfo_valid() && (stp_info.vbits & 0x4000))
857 ret = sysfs_emit(buf, "%i\n", (int)(s16)stp_info.tzo);
858 mutex_unlock(&stp_mutex);
859 return ret;
860}
861
862static DEVICE_ATTR_RO(time_zone_offset);
863
864static ssize_t timing_mode_show(struct device *dev,
865 struct device_attribute *attr,
866 char *buf)
867{
868 ssize_t ret = -ENODATA;
869
870 mutex_lock(&stp_mutex);
871 if (stpinfo_valid())
872 ret = sysfs_emit(buf, "%i\n", stp_info.tmd);
873 mutex_unlock(&stp_mutex);
874 return ret;
875}
876
877static DEVICE_ATTR_RO(timing_mode);
878
879static ssize_t timing_state_show(struct device *dev,
880 struct device_attribute *attr,
881 char *buf)
882{
883 ssize_t ret = -ENODATA;
884
885 mutex_lock(&stp_mutex);
886 if (stpinfo_valid())
887 ret = sysfs_emit(buf, "%i\n", stp_info.tst);
888 mutex_unlock(&stp_mutex);
889 return ret;
890}
891
892static DEVICE_ATTR_RO(timing_state);
893
894static ssize_t online_show(struct device *dev,
895 struct device_attribute *attr,
896 char *buf)
897{
898 return sysfs_emit(buf, "%i\n", stp_online);
899}
900
901static ssize_t online_store(struct device *dev,
902 struct device_attribute *attr,
903 const char *buf, size_t count)
904{
905 unsigned int value;
906
907 value = simple_strtoul(buf, NULL, 0);
908 if (value != 0 && value != 1)
909 return -EINVAL;
910 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
911 return -EOPNOTSUPP;
912 mutex_lock(&stp_mutex);
913 stp_online = value;
914 if (stp_online)
915 set_bit(CLOCK_SYNC_STP, &clock_sync_flags);
916 else
917 clear_bit(CLOCK_SYNC_STP, &clock_sync_flags);
918 queue_work(time_sync_wq, &stp_work);
919 mutex_unlock(&stp_mutex);
920 return count;
921}
922
923/*
924 * Can't use DEVICE_ATTR because the attribute should be named
925 * stp/online but dev_attr_online already exists in this file ..
926 */
927static DEVICE_ATTR_RW(online);
928
929static struct attribute *stp_dev_attrs[] = {
930 &dev_attr_ctn_id.attr,
931 &dev_attr_ctn_type.attr,
932 &dev_attr_dst_offset.attr,
933 &dev_attr_leap_seconds.attr,
934 &dev_attr_online.attr,
935 &dev_attr_leap_seconds_scheduled.attr,
936 &dev_attr_stratum.attr,
937 &dev_attr_time_offset.attr,
938 &dev_attr_time_zone_offset.attr,
939 &dev_attr_timing_mode.attr,
940 &dev_attr_timing_state.attr,
941 NULL
942};
943ATTRIBUTE_GROUPS(stp_dev);
944
945static int __init stp_init_sysfs(void)
946{
947 return subsys_system_register(&stp_subsys, stp_dev_groups);
948}
949
950device_initcall(stp_init_sysfs);
1/*
2 * Time of day based timer functions.
3 *
4 * S390 version
5 * Copyright IBM Corp. 1999, 2008
6 * Author(s): Hartmut Penner (hp@de.ibm.com),
7 * Martin Schwidefsky (schwidefsky@de.ibm.com),
8 * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
9 *
10 * Derived from "arch/i386/kernel/time.c"
11 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
12 */
13
14#define KMSG_COMPONENT "time"
15#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
16
17#include <linux/kernel_stat.h>
18#include <linux/errno.h>
19#include <linux/module.h>
20#include <linux/sched.h>
21#include <linux/kernel.h>
22#include <linux/param.h>
23#include <linux/string.h>
24#include <linux/mm.h>
25#include <linux/interrupt.h>
26#include <linux/cpu.h>
27#include <linux/stop_machine.h>
28#include <linux/time.h>
29#include <linux/device.h>
30#include <linux/delay.h>
31#include <linux/init.h>
32#include <linux/smp.h>
33#include <linux/types.h>
34#include <linux/profile.h>
35#include <linux/timex.h>
36#include <linux/notifier.h>
37#include <linux/timekeeper_internal.h>
38#include <linux/clockchips.h>
39#include <linux/gfp.h>
40#include <linux/kprobes.h>
41#include <asm/uaccess.h>
42#include <asm/delay.h>
43#include <asm/div64.h>
44#include <asm/vdso.h>
45#include <asm/irq.h>
46#include <asm/irq_regs.h>
47#include <asm/vtimer.h>
48#include <asm/etr.h>
49#include <asm/cio.h>
50#include "entry.h"
51
52/* change this if you have some constant time drift */
53#define USECS_PER_JIFFY ((unsigned long) 1000000/HZ)
54#define CLK_TICKS_PER_JIFFY ((unsigned long) USECS_PER_JIFFY << 12)
55
56u64 sched_clock_base_cc = -1; /* Force to data section. */
57EXPORT_SYMBOL_GPL(sched_clock_base_cc);
58
59static DEFINE_PER_CPU(struct clock_event_device, comparators);
60
61ATOMIC_NOTIFIER_HEAD(s390_epoch_delta_notifier);
62EXPORT_SYMBOL(s390_epoch_delta_notifier);
63
64/*
65 * Scheduler clock - returns current time in nanosec units.
66 */
67unsigned long long notrace sched_clock(void)
68{
69 return tod_to_ns(get_tod_clock_monotonic());
70}
71NOKPROBE_SYMBOL(sched_clock);
72
73/*
74 * Monotonic_clock - returns # of nanoseconds passed since time_init()
75 */
76unsigned long long monotonic_clock(void)
77{
78 return sched_clock();
79}
80EXPORT_SYMBOL(monotonic_clock);
81
82void tod_to_timeval(__u64 todval, struct timespec64 *xt)
83{
84 unsigned long long sec;
85
86 sec = todval >> 12;
87 do_div(sec, 1000000);
88 xt->tv_sec = sec;
89 todval -= (sec * 1000000) << 12;
90 xt->tv_nsec = ((todval * 1000) >> 12);
91}
92EXPORT_SYMBOL(tod_to_timeval);
93
94void clock_comparator_work(void)
95{
96 struct clock_event_device *cd;
97
98 S390_lowcore.clock_comparator = -1ULL;
99 cd = this_cpu_ptr(&comparators);
100 cd->event_handler(cd);
101}
102
103/*
104 * Fixup the clock comparator.
105 */
106static void fixup_clock_comparator(unsigned long long delta)
107{
108 /* If nobody is waiting there's nothing to fix. */
109 if (S390_lowcore.clock_comparator == -1ULL)
110 return;
111 S390_lowcore.clock_comparator += delta;
112 set_clock_comparator(S390_lowcore.clock_comparator);
113}
114
115static int s390_next_event(unsigned long delta,
116 struct clock_event_device *evt)
117{
118 S390_lowcore.clock_comparator = get_tod_clock() + delta;
119 set_clock_comparator(S390_lowcore.clock_comparator);
120 return 0;
121}
122
123/*
124 * Set up lowcore and control register of the current cpu to
125 * enable TOD clock and clock comparator interrupts.
126 */
127void init_cpu_timer(void)
128{
129 struct clock_event_device *cd;
130 int cpu;
131
132 S390_lowcore.clock_comparator = -1ULL;
133 set_clock_comparator(S390_lowcore.clock_comparator);
134
135 cpu = smp_processor_id();
136 cd = &per_cpu(comparators, cpu);
137 cd->name = "comparator";
138 cd->features = CLOCK_EVT_FEAT_ONESHOT;
139 cd->mult = 16777;
140 cd->shift = 12;
141 cd->min_delta_ns = 1;
142 cd->max_delta_ns = LONG_MAX;
143 cd->rating = 400;
144 cd->cpumask = cpumask_of(cpu);
145 cd->set_next_event = s390_next_event;
146
147 clockevents_register_device(cd);
148
149 /* Enable clock comparator timer interrupt. */
150 __ctl_set_bit(0,11);
151
152 /* Always allow the timing alert external interrupt. */
153 __ctl_set_bit(0, 4);
154}
155
156static void clock_comparator_interrupt(struct ext_code ext_code,
157 unsigned int param32,
158 unsigned long param64)
159{
160 inc_irq_stat(IRQEXT_CLK);
161 if (S390_lowcore.clock_comparator == -1ULL)
162 set_clock_comparator(S390_lowcore.clock_comparator);
163}
164
165static void etr_timing_alert(struct etr_irq_parm *);
166static void stp_timing_alert(struct stp_irq_parm *);
167
168static void timing_alert_interrupt(struct ext_code ext_code,
169 unsigned int param32, unsigned long param64)
170{
171 inc_irq_stat(IRQEXT_TLA);
172 if (param32 & 0x00c40000)
173 etr_timing_alert((struct etr_irq_parm *) ¶m32);
174 if (param32 & 0x00038000)
175 stp_timing_alert((struct stp_irq_parm *) ¶m32);
176}
177
178static void etr_reset(void);
179static void stp_reset(void);
180
181void read_persistent_clock64(struct timespec64 *ts)
182{
183 tod_to_timeval(get_tod_clock() - TOD_UNIX_EPOCH, ts);
184}
185
186void read_boot_clock64(struct timespec64 *ts)
187{
188 tod_to_timeval(sched_clock_base_cc - TOD_UNIX_EPOCH, ts);
189}
190
191static cycle_t read_tod_clock(struct clocksource *cs)
192{
193 return get_tod_clock();
194}
195
196static struct clocksource clocksource_tod = {
197 .name = "tod",
198 .rating = 400,
199 .read = read_tod_clock,
200 .mask = -1ULL,
201 .mult = 1000,
202 .shift = 12,
203 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
204};
205
206struct clocksource * __init clocksource_default_clock(void)
207{
208 return &clocksource_tod;
209}
210
211void update_vsyscall(struct timekeeper *tk)
212{
213 u64 nsecps;
214
215 if (tk->tkr_mono.clock != &clocksource_tod)
216 return;
217
218 /* Make userspace gettimeofday spin until we're done. */
219 ++vdso_data->tb_update_count;
220 smp_wmb();
221 vdso_data->xtime_tod_stamp = tk->tkr_mono.cycle_last;
222 vdso_data->xtime_clock_sec = tk->xtime_sec;
223 vdso_data->xtime_clock_nsec = tk->tkr_mono.xtime_nsec;
224 vdso_data->wtom_clock_sec =
225 tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
226 vdso_data->wtom_clock_nsec = tk->tkr_mono.xtime_nsec +
227 + ((u64) tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift);
228 nsecps = (u64) NSEC_PER_SEC << tk->tkr_mono.shift;
229 while (vdso_data->wtom_clock_nsec >= nsecps) {
230 vdso_data->wtom_clock_nsec -= nsecps;
231 vdso_data->wtom_clock_sec++;
232 }
233
234 vdso_data->xtime_coarse_sec = tk->xtime_sec;
235 vdso_data->xtime_coarse_nsec =
236 (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
237 vdso_data->wtom_coarse_sec =
238 vdso_data->xtime_coarse_sec + tk->wall_to_monotonic.tv_sec;
239 vdso_data->wtom_coarse_nsec =
240 vdso_data->xtime_coarse_nsec + tk->wall_to_monotonic.tv_nsec;
241 while (vdso_data->wtom_coarse_nsec >= NSEC_PER_SEC) {
242 vdso_data->wtom_coarse_nsec -= NSEC_PER_SEC;
243 vdso_data->wtom_coarse_sec++;
244 }
245
246 vdso_data->tk_mult = tk->tkr_mono.mult;
247 vdso_data->tk_shift = tk->tkr_mono.shift;
248 smp_wmb();
249 ++vdso_data->tb_update_count;
250}
251
252extern struct timezone sys_tz;
253
254void update_vsyscall_tz(void)
255{
256 /* Make userspace gettimeofday spin until we're done. */
257 ++vdso_data->tb_update_count;
258 smp_wmb();
259 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
260 vdso_data->tz_dsttime = sys_tz.tz_dsttime;
261 smp_wmb();
262 ++vdso_data->tb_update_count;
263}
264
265/*
266 * Initialize the TOD clock and the CPU timer of
267 * the boot cpu.
268 */
269void __init time_init(void)
270{
271 /* Reset time synchronization interfaces. */
272 etr_reset();
273 stp_reset();
274
275 /* request the clock comparator external interrupt */
276 if (register_external_irq(EXT_IRQ_CLK_COMP, clock_comparator_interrupt))
277 panic("Couldn't request external interrupt 0x1004");
278
279 /* request the timing alert external interrupt */
280 if (register_external_irq(EXT_IRQ_TIMING_ALERT, timing_alert_interrupt))
281 panic("Couldn't request external interrupt 0x1406");
282
283 if (__clocksource_register(&clocksource_tod) != 0)
284 panic("Could not register TOD clock source");
285
286 /* Enable TOD clock interrupts on the boot cpu. */
287 init_cpu_timer();
288
289 /* Enable cpu timer interrupts on the boot cpu. */
290 vtime_init();
291}
292
293/*
294 * The time is "clock". old is what we think the time is.
295 * Adjust the value by a multiple of jiffies and add the delta to ntp.
296 * "delay" is an approximation how long the synchronization took. If
297 * the time correction is positive, then "delay" is subtracted from
298 * the time difference and only the remaining part is passed to ntp.
299 */
300static unsigned long long adjust_time(unsigned long long old,
301 unsigned long long clock,
302 unsigned long long delay)
303{
304 unsigned long long delta, ticks;
305 struct timex adjust;
306
307 if (clock > old) {
308 /* It is later than we thought. */
309 delta = ticks = clock - old;
310 delta = ticks = (delta < delay) ? 0 : delta - delay;
311 delta -= do_div(ticks, CLK_TICKS_PER_JIFFY);
312 adjust.offset = ticks * (1000000 / HZ);
313 } else {
314 /* It is earlier than we thought. */
315 delta = ticks = old - clock;
316 delta -= do_div(ticks, CLK_TICKS_PER_JIFFY);
317 delta = -delta;
318 adjust.offset = -ticks * (1000000 / HZ);
319 }
320 sched_clock_base_cc += delta;
321 if (adjust.offset != 0) {
322 pr_notice("The ETR interface has adjusted the clock "
323 "by %li microseconds\n", adjust.offset);
324 adjust.modes = ADJ_OFFSET_SINGLESHOT;
325 do_adjtimex(&adjust);
326 }
327 return delta;
328}
329
330static DEFINE_PER_CPU(atomic_t, clock_sync_word);
331static DEFINE_MUTEX(clock_sync_mutex);
332static unsigned long clock_sync_flags;
333
334#define CLOCK_SYNC_HAS_ETR 0
335#define CLOCK_SYNC_HAS_STP 1
336#define CLOCK_SYNC_ETR 2
337#define CLOCK_SYNC_STP 3
338
339/*
340 * The synchronous get_clock function. It will write the current clock
341 * value to the clock pointer and return 0 if the clock is in sync with
342 * the external time source. If the clock mode is local it will return
343 * -EOPNOTSUPP and -EAGAIN if the clock is not in sync with the external
344 * reference.
345 */
346int get_sync_clock(unsigned long long *clock)
347{
348 atomic_t *sw_ptr;
349 unsigned int sw0, sw1;
350
351 sw_ptr = &get_cpu_var(clock_sync_word);
352 sw0 = atomic_read(sw_ptr);
353 *clock = get_tod_clock();
354 sw1 = atomic_read(sw_ptr);
355 put_cpu_var(clock_sync_word);
356 if (sw0 == sw1 && (sw0 & 0x80000000U))
357 /* Success: time is in sync. */
358 return 0;
359 if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags) &&
360 !test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
361 return -EOPNOTSUPP;
362 if (!test_bit(CLOCK_SYNC_ETR, &clock_sync_flags) &&
363 !test_bit(CLOCK_SYNC_STP, &clock_sync_flags))
364 return -EACCES;
365 return -EAGAIN;
366}
367EXPORT_SYMBOL(get_sync_clock);
368
369/*
370 * Make get_sync_clock return -EAGAIN.
371 */
372static void disable_sync_clock(void *dummy)
373{
374 atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
375 /*
376 * Clear the in-sync bit 2^31. All get_sync_clock calls will
377 * fail until the sync bit is turned back on. In addition
378 * increase the "sequence" counter to avoid the race of an
379 * etr event and the complete recovery against get_sync_clock.
380 */
381 atomic_andnot(0x80000000, sw_ptr);
382 atomic_inc(sw_ptr);
383}
384
385/*
386 * Make get_sync_clock return 0 again.
387 * Needs to be called from a context disabled for preemption.
388 */
389static void enable_sync_clock(void)
390{
391 atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
392 atomic_or(0x80000000, sw_ptr);
393}
394
395/*
396 * Function to check if the clock is in sync.
397 */
398static inline int check_sync_clock(void)
399{
400 atomic_t *sw_ptr;
401 int rc;
402
403 sw_ptr = &get_cpu_var(clock_sync_word);
404 rc = (atomic_read(sw_ptr) & 0x80000000U) != 0;
405 put_cpu_var(clock_sync_word);
406 return rc;
407}
408
409/* Single threaded workqueue used for etr and stp sync events */
410static struct workqueue_struct *time_sync_wq;
411
412static void __init time_init_wq(void)
413{
414 if (time_sync_wq)
415 return;
416 time_sync_wq = create_singlethread_workqueue("timesync");
417}
418
419/*
420 * External Time Reference (ETR) code.
421 */
422static int etr_port0_online;
423static int etr_port1_online;
424static int etr_steai_available;
425
426static int __init early_parse_etr(char *p)
427{
428 if (strncmp(p, "off", 3) == 0)
429 etr_port0_online = etr_port1_online = 0;
430 else if (strncmp(p, "port0", 5) == 0)
431 etr_port0_online = 1;
432 else if (strncmp(p, "port1", 5) == 0)
433 etr_port1_online = 1;
434 else if (strncmp(p, "on", 2) == 0)
435 etr_port0_online = etr_port1_online = 1;
436 return 0;
437}
438early_param("etr", early_parse_etr);
439
440enum etr_event {
441 ETR_EVENT_PORT0_CHANGE,
442 ETR_EVENT_PORT1_CHANGE,
443 ETR_EVENT_PORT_ALERT,
444 ETR_EVENT_SYNC_CHECK,
445 ETR_EVENT_SWITCH_LOCAL,
446 ETR_EVENT_UPDATE,
447};
448
449/*
450 * Valid bit combinations of the eacr register are (x = don't care):
451 * e0 e1 dp p0 p1 ea es sl
452 * 0 0 x 0 0 0 0 0 initial, disabled state
453 * 0 0 x 0 1 1 0 0 port 1 online
454 * 0 0 x 1 0 1 0 0 port 0 online
455 * 0 0 x 1 1 1 0 0 both ports online
456 * 0 1 x 0 1 1 0 0 port 1 online and usable, ETR or PPS mode
457 * 0 1 x 0 1 1 0 1 port 1 online, usable and ETR mode
458 * 0 1 x 0 1 1 1 0 port 1 online, usable, PPS mode, in-sync
459 * 0 1 x 0 1 1 1 1 port 1 online, usable, ETR mode, in-sync
460 * 0 1 x 1 1 1 0 0 both ports online, port 1 usable
461 * 0 1 x 1 1 1 1 0 both ports online, port 1 usable, PPS mode, in-sync
462 * 0 1 x 1 1 1 1 1 both ports online, port 1 usable, ETR mode, in-sync
463 * 1 0 x 1 0 1 0 0 port 0 online and usable, ETR or PPS mode
464 * 1 0 x 1 0 1 0 1 port 0 online, usable and ETR mode
465 * 1 0 x 1 0 1 1 0 port 0 online, usable, PPS mode, in-sync
466 * 1 0 x 1 0 1 1 1 port 0 online, usable, ETR mode, in-sync
467 * 1 0 x 1 1 1 0 0 both ports online, port 0 usable
468 * 1 0 x 1 1 1 1 0 both ports online, port 0 usable, PPS mode, in-sync
469 * 1 0 x 1 1 1 1 1 both ports online, port 0 usable, ETR mode, in-sync
470 * 1 1 x 1 1 1 1 0 both ports online & usable, ETR, in-sync
471 * 1 1 x 1 1 1 1 1 both ports online & usable, ETR, in-sync
472 */
473static struct etr_eacr etr_eacr;
474static u64 etr_tolec; /* time of last eacr update */
475static struct etr_aib etr_port0;
476static int etr_port0_uptodate;
477static struct etr_aib etr_port1;
478static int etr_port1_uptodate;
479static unsigned long etr_events;
480static struct timer_list etr_timer;
481
482static void etr_timeout(unsigned long dummy);
483static void etr_work_fn(struct work_struct *work);
484static DEFINE_MUTEX(etr_work_mutex);
485static DECLARE_WORK(etr_work, etr_work_fn);
486
487/*
488 * Reset ETR attachment.
489 */
490static void etr_reset(void)
491{
492 etr_eacr = (struct etr_eacr) {
493 .e0 = 0, .e1 = 0, ._pad0 = 4, .dp = 0,
494 .p0 = 0, .p1 = 0, ._pad1 = 0, .ea = 0,
495 .es = 0, .sl = 0 };
496 if (etr_setr(&etr_eacr) == 0) {
497 etr_tolec = get_tod_clock();
498 set_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags);
499 if (etr_port0_online && etr_port1_online)
500 set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
501 } else if (etr_port0_online || etr_port1_online) {
502 pr_warn("The real or virtual hardware system does not provide an ETR interface\n");
503 etr_port0_online = etr_port1_online = 0;
504 }
505}
506
507static int __init etr_init(void)
508{
509 struct etr_aib aib;
510
511 if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags))
512 return 0;
513 time_init_wq();
514 /* Check if this machine has the steai instruction. */
515 if (etr_steai(&aib, ETR_STEAI_STEPPING_PORT) == 0)
516 etr_steai_available = 1;
517 setup_timer(&etr_timer, etr_timeout, 0UL);
518 if (etr_port0_online) {
519 set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
520 queue_work(time_sync_wq, &etr_work);
521 }
522 if (etr_port1_online) {
523 set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
524 queue_work(time_sync_wq, &etr_work);
525 }
526 return 0;
527}
528
529arch_initcall(etr_init);
530
531/*
532 * Two sorts of ETR machine checks. The architecture reads:
533 * "When a machine-check niterruption occurs and if a switch-to-local or
534 * ETR-sync-check interrupt request is pending but disabled, this pending
535 * disabled interruption request is indicated and is cleared".
536 * Which means that we can get etr_switch_to_local events from the machine
537 * check handler although the interruption condition is disabled. Lovely..
538 */
539
540/*
541 * Switch to local machine check. This is called when the last usable
542 * ETR port goes inactive. After switch to local the clock is not in sync.
543 */
544int etr_switch_to_local(void)
545{
546 if (!etr_eacr.sl)
547 return 0;
548 disable_sync_clock(NULL);
549 if (!test_and_set_bit(ETR_EVENT_SWITCH_LOCAL, &etr_events)) {
550 etr_eacr.es = etr_eacr.sl = 0;
551 etr_setr(&etr_eacr);
552 return 1;
553 }
554 return 0;
555}
556
557/*
558 * ETR sync check machine check. This is called when the ETR OTE and the
559 * local clock OTE are farther apart than the ETR sync check tolerance.
560 * After a ETR sync check the clock is not in sync. The machine check
561 * is broadcasted to all cpus at the same time.
562 */
563int etr_sync_check(void)
564{
565 if (!etr_eacr.es)
566 return 0;
567 disable_sync_clock(NULL);
568 if (!test_and_set_bit(ETR_EVENT_SYNC_CHECK, &etr_events)) {
569 etr_eacr.es = 0;
570 etr_setr(&etr_eacr);
571 return 1;
572 }
573 return 0;
574}
575
576void etr_queue_work(void)
577{
578 queue_work(time_sync_wq, &etr_work);
579}
580
581/*
582 * ETR timing alert. There are two causes:
583 * 1) port state change, check the usability of the port
584 * 2) port alert, one of the ETR-data-validity bits (v1-v2 bits of the
585 * sldr-status word) or ETR-data word 1 (edf1) or ETR-data word 3 (edf3)
586 * or ETR-data word 4 (edf4) has changed.
587 */
588static void etr_timing_alert(struct etr_irq_parm *intparm)
589{
590 if (intparm->pc0)
591 /* ETR port 0 state change. */
592 set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
593 if (intparm->pc1)
594 /* ETR port 1 state change. */
595 set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
596 if (intparm->eai)
597 /*
598 * ETR port alert on either port 0, 1 or both.
599 * Both ports are not up-to-date now.
600 */
601 set_bit(ETR_EVENT_PORT_ALERT, &etr_events);
602 queue_work(time_sync_wq, &etr_work);
603}
604
605static void etr_timeout(unsigned long dummy)
606{
607 set_bit(ETR_EVENT_UPDATE, &etr_events);
608 queue_work(time_sync_wq, &etr_work);
609}
610
611/*
612 * Check if the etr mode is pss.
613 */
614static inline int etr_mode_is_pps(struct etr_eacr eacr)
615{
616 return eacr.es && !eacr.sl;
617}
618
619/*
620 * Check if the etr mode is etr.
621 */
622static inline int etr_mode_is_etr(struct etr_eacr eacr)
623{
624 return eacr.es && eacr.sl;
625}
626
627/*
628 * Check if the port can be used for TOD synchronization.
629 * For PPS mode the port has to receive OTEs. For ETR mode
630 * the port has to receive OTEs, the ETR stepping bit has to
631 * be zero and the validity bits for data frame 1, 2, and 3
632 * have to be 1.
633 */
634static int etr_port_valid(struct etr_aib *aib, int port)
635{
636 unsigned int psc;
637
638 /* Check that this port is receiving OTEs. */
639 if (aib->tsp == 0)
640 return 0;
641
642 psc = port ? aib->esw.psc1 : aib->esw.psc0;
643 if (psc == etr_lpsc_pps_mode)
644 return 1;
645 if (psc == etr_lpsc_operational_step)
646 return !aib->esw.y && aib->slsw.v1 &&
647 aib->slsw.v2 && aib->slsw.v3;
648 return 0;
649}
650
651/*
652 * Check if two ports are on the same network.
653 */
654static int etr_compare_network(struct etr_aib *aib1, struct etr_aib *aib2)
655{
656 // FIXME: any other fields we have to compare?
657 return aib1->edf1.net_id == aib2->edf1.net_id;
658}
659
660/*
661 * Wrapper for etr_stei that converts physical port states
662 * to logical port states to be consistent with the output
663 * of stetr (see etr_psc vs. etr_lpsc).
664 */
665static void etr_steai_cv(struct etr_aib *aib, unsigned int func)
666{
667 BUG_ON(etr_steai(aib, func) != 0);
668 /* Convert port state to logical port state. */
669 if (aib->esw.psc0 == 1)
670 aib->esw.psc0 = 2;
671 else if (aib->esw.psc0 == 0 && aib->esw.p == 0)
672 aib->esw.psc0 = 1;
673 if (aib->esw.psc1 == 1)
674 aib->esw.psc1 = 2;
675 else if (aib->esw.psc1 == 0 && aib->esw.p == 1)
676 aib->esw.psc1 = 1;
677}
678
679/*
680 * Check if the aib a2 is still connected to the same attachment as
681 * aib a1, the etv values differ by one and a2 is valid.
682 */
683static int etr_aib_follows(struct etr_aib *a1, struct etr_aib *a2, int p)
684{
685 int state_a1, state_a2;
686
687 /* Paranoia check: e0/e1 should better be the same. */
688 if (a1->esw.eacr.e0 != a2->esw.eacr.e0 ||
689 a1->esw.eacr.e1 != a2->esw.eacr.e1)
690 return 0;
691
692 /* Still connected to the same etr ? */
693 state_a1 = p ? a1->esw.psc1 : a1->esw.psc0;
694 state_a2 = p ? a2->esw.psc1 : a2->esw.psc0;
695 if (state_a1 == etr_lpsc_operational_step) {
696 if (state_a2 != etr_lpsc_operational_step ||
697 a1->edf1.net_id != a2->edf1.net_id ||
698 a1->edf1.etr_id != a2->edf1.etr_id ||
699 a1->edf1.etr_pn != a2->edf1.etr_pn)
700 return 0;
701 } else if (state_a2 != etr_lpsc_pps_mode)
702 return 0;
703
704 /* The ETV value of a2 needs to be ETV of a1 + 1. */
705 if (a1->edf2.etv + 1 != a2->edf2.etv)
706 return 0;
707
708 if (!etr_port_valid(a2, p))
709 return 0;
710
711 return 1;
712}
713
714struct clock_sync_data {
715 atomic_t cpus;
716 int in_sync;
717 unsigned long long fixup_cc;
718 int etr_port;
719 struct etr_aib *etr_aib;
720};
721
722static void clock_sync_cpu(struct clock_sync_data *sync)
723{
724 atomic_dec(&sync->cpus);
725 enable_sync_clock();
726 /*
727 * This looks like a busy wait loop but it isn't. etr_sync_cpus
728 * is called on all other cpus while the TOD clocks is stopped.
729 * __udelay will stop the cpu on an enabled wait psw until the
730 * TOD is running again.
731 */
732 while (sync->in_sync == 0) {
733 __udelay(1);
734 /*
735 * A different cpu changes *in_sync. Therefore use
736 * barrier() to force memory access.
737 */
738 barrier();
739 }
740 if (sync->in_sync != 1)
741 /* Didn't work. Clear per-cpu in sync bit again. */
742 disable_sync_clock(NULL);
743 /*
744 * This round of TOD syncing is done. Set the clock comparator
745 * to the next tick and let the processor continue.
746 */
747 fixup_clock_comparator(sync->fixup_cc);
748}
749
750/*
751 * Sync the TOD clock using the port referred to by aibp. This port
752 * has to be enabled and the other port has to be disabled. The
753 * last eacr update has to be more than 1.6 seconds in the past.
754 */
755static int etr_sync_clock(void *data)
756{
757 static int first;
758 unsigned long long clock, old_clock, clock_delta, delay, delta;
759 struct clock_sync_data *etr_sync;
760 struct etr_aib *sync_port, *aib;
761 int port;
762 int rc;
763
764 etr_sync = data;
765
766 if (xchg(&first, 1) == 1) {
767 /* Slave */
768 clock_sync_cpu(etr_sync);
769 return 0;
770 }
771
772 /* Wait until all other cpus entered the sync function. */
773 while (atomic_read(&etr_sync->cpus) != 0)
774 cpu_relax();
775
776 port = etr_sync->etr_port;
777 aib = etr_sync->etr_aib;
778 sync_port = (port == 0) ? &etr_port0 : &etr_port1;
779 enable_sync_clock();
780
781 /* Set clock to next OTE. */
782 __ctl_set_bit(14, 21);
783 __ctl_set_bit(0, 29);
784 clock = ((unsigned long long) (aib->edf2.etv + 1)) << 32;
785 old_clock = get_tod_clock();
786 if (set_tod_clock(clock) == 0) {
787 __udelay(1); /* Wait for the clock to start. */
788 __ctl_clear_bit(0, 29);
789 __ctl_clear_bit(14, 21);
790 etr_stetr(aib);
791 /* Adjust Linux timing variables. */
792 delay = (unsigned long long)
793 (aib->edf2.etv - sync_port->edf2.etv) << 32;
794 delta = adjust_time(old_clock, clock, delay);
795 clock_delta = clock - old_clock;
796 atomic_notifier_call_chain(&s390_epoch_delta_notifier, 0,
797 &clock_delta);
798 etr_sync->fixup_cc = delta;
799 fixup_clock_comparator(delta);
800 /* Verify that the clock is properly set. */
801 if (!etr_aib_follows(sync_port, aib, port)) {
802 /* Didn't work. */
803 disable_sync_clock(NULL);
804 etr_sync->in_sync = -EAGAIN;
805 rc = -EAGAIN;
806 } else {
807 etr_sync->in_sync = 1;
808 rc = 0;
809 }
810 } else {
811 /* Could not set the clock ?!? */
812 __ctl_clear_bit(0, 29);
813 __ctl_clear_bit(14, 21);
814 disable_sync_clock(NULL);
815 etr_sync->in_sync = -EAGAIN;
816 rc = -EAGAIN;
817 }
818 xchg(&first, 0);
819 return rc;
820}
821
822static int etr_sync_clock_stop(struct etr_aib *aib, int port)
823{
824 struct clock_sync_data etr_sync;
825 struct etr_aib *sync_port;
826 int follows;
827 int rc;
828
829 /* Check if the current aib is adjacent to the sync port aib. */
830 sync_port = (port == 0) ? &etr_port0 : &etr_port1;
831 follows = etr_aib_follows(sync_port, aib, port);
832 memcpy(sync_port, aib, sizeof(*aib));
833 if (!follows)
834 return -EAGAIN;
835 memset(&etr_sync, 0, sizeof(etr_sync));
836 etr_sync.etr_aib = aib;
837 etr_sync.etr_port = port;
838 get_online_cpus();
839 atomic_set(&etr_sync.cpus, num_online_cpus() - 1);
840 rc = stop_machine(etr_sync_clock, &etr_sync, cpu_online_mask);
841 put_online_cpus();
842 return rc;
843}
844
845/*
846 * Handle the immediate effects of the different events.
847 * The port change event is used for online/offline changes.
848 */
849static struct etr_eacr etr_handle_events(struct etr_eacr eacr)
850{
851 if (test_and_clear_bit(ETR_EVENT_SYNC_CHECK, &etr_events))
852 eacr.es = 0;
853 if (test_and_clear_bit(ETR_EVENT_SWITCH_LOCAL, &etr_events))
854 eacr.es = eacr.sl = 0;
855 if (test_and_clear_bit(ETR_EVENT_PORT_ALERT, &etr_events))
856 etr_port0_uptodate = etr_port1_uptodate = 0;
857
858 if (test_and_clear_bit(ETR_EVENT_PORT0_CHANGE, &etr_events)) {
859 if (eacr.e0)
860 /*
861 * Port change of an enabled port. We have to
862 * assume that this can have caused an stepping
863 * port switch.
864 */
865 etr_tolec = get_tod_clock();
866 eacr.p0 = etr_port0_online;
867 if (!eacr.p0)
868 eacr.e0 = 0;
869 etr_port0_uptodate = 0;
870 }
871 if (test_and_clear_bit(ETR_EVENT_PORT1_CHANGE, &etr_events)) {
872 if (eacr.e1)
873 /*
874 * Port change of an enabled port. We have to
875 * assume that this can have caused an stepping
876 * port switch.
877 */
878 etr_tolec = get_tod_clock();
879 eacr.p1 = etr_port1_online;
880 if (!eacr.p1)
881 eacr.e1 = 0;
882 etr_port1_uptodate = 0;
883 }
884 clear_bit(ETR_EVENT_UPDATE, &etr_events);
885 return eacr;
886}
887
888/*
889 * Set up a timer that expires after the etr_tolec + 1.6 seconds if
890 * one of the ports needs an update.
891 */
892static void etr_set_tolec_timeout(unsigned long long now)
893{
894 unsigned long micros;
895
896 if ((!etr_eacr.p0 || etr_port0_uptodate) &&
897 (!etr_eacr.p1 || etr_port1_uptodate))
898 return;
899 micros = (now > etr_tolec) ? ((now - etr_tolec) >> 12) : 0;
900 micros = (micros > 1600000) ? 0 : 1600000 - micros;
901 mod_timer(&etr_timer, jiffies + (micros * HZ) / 1000000 + 1);
902}
903
904/*
905 * Set up a time that expires after 1/2 second.
906 */
907static void etr_set_sync_timeout(void)
908{
909 mod_timer(&etr_timer, jiffies + HZ/2);
910}
911
912/*
913 * Update the aib information for one or both ports.
914 */
915static struct etr_eacr etr_handle_update(struct etr_aib *aib,
916 struct etr_eacr eacr)
917{
918 /* With both ports disabled the aib information is useless. */
919 if (!eacr.e0 && !eacr.e1)
920 return eacr;
921
922 /* Update port0 or port1 with aib stored in etr_work_fn. */
923 if (aib->esw.q == 0) {
924 /* Information for port 0 stored. */
925 if (eacr.p0 && !etr_port0_uptodate) {
926 etr_port0 = *aib;
927 if (etr_port0_online)
928 etr_port0_uptodate = 1;
929 }
930 } else {
931 /* Information for port 1 stored. */
932 if (eacr.p1 && !etr_port1_uptodate) {
933 etr_port1 = *aib;
934 if (etr_port0_online)
935 etr_port1_uptodate = 1;
936 }
937 }
938
939 /*
940 * Do not try to get the alternate port aib if the clock
941 * is not in sync yet.
942 */
943 if (!eacr.es || !check_sync_clock())
944 return eacr;
945
946 /*
947 * If steai is available we can get the information about
948 * the other port immediately. If only stetr is available the
949 * data-port bit toggle has to be used.
950 */
951 if (etr_steai_available) {
952 if (eacr.p0 && !etr_port0_uptodate) {
953 etr_steai_cv(&etr_port0, ETR_STEAI_PORT_0);
954 etr_port0_uptodate = 1;
955 }
956 if (eacr.p1 && !etr_port1_uptodate) {
957 etr_steai_cv(&etr_port1, ETR_STEAI_PORT_1);
958 etr_port1_uptodate = 1;
959 }
960 } else {
961 /*
962 * One port was updated above, if the other
963 * port is not uptodate toggle dp bit.
964 */
965 if ((eacr.p0 && !etr_port0_uptodate) ||
966 (eacr.p1 && !etr_port1_uptodate))
967 eacr.dp ^= 1;
968 else
969 eacr.dp = 0;
970 }
971 return eacr;
972}
973
974/*
975 * Write new etr control register if it differs from the current one.
976 * Return 1 if etr_tolec has been updated as well.
977 */
978static void etr_update_eacr(struct etr_eacr eacr)
979{
980 int dp_changed;
981
982 if (memcmp(&etr_eacr, &eacr, sizeof(eacr)) == 0)
983 /* No change, return. */
984 return;
985 /*
986 * The disable of an active port of the change of the data port
987 * bit can/will cause a change in the data port.
988 */
989 dp_changed = etr_eacr.e0 > eacr.e0 || etr_eacr.e1 > eacr.e1 ||
990 (etr_eacr.dp ^ eacr.dp) != 0;
991 etr_eacr = eacr;
992 etr_setr(&etr_eacr);
993 if (dp_changed)
994 etr_tolec = get_tod_clock();
995}
996
997/*
998 * ETR work. In this function you'll find the main logic. In
999 * particular this is the only function that calls etr_update_eacr(),
1000 * it "controls" the etr control register.
1001 */
1002static void etr_work_fn(struct work_struct *work)
1003{
1004 unsigned long long now;
1005 struct etr_eacr eacr;
1006 struct etr_aib aib;
1007 int sync_port;
1008
1009 /* prevent multiple execution. */
1010 mutex_lock(&etr_work_mutex);
1011
1012 /* Create working copy of etr_eacr. */
1013 eacr = etr_eacr;
1014
1015 /* Check for the different events and their immediate effects. */
1016 eacr = etr_handle_events(eacr);
1017
1018 /* Check if ETR is supposed to be active. */
1019 eacr.ea = eacr.p0 || eacr.p1;
1020 if (!eacr.ea) {
1021 /* Both ports offline. Reset everything. */
1022 eacr.dp = eacr.es = eacr.sl = 0;
1023 on_each_cpu(disable_sync_clock, NULL, 1);
1024 del_timer_sync(&etr_timer);
1025 etr_update_eacr(eacr);
1026 goto out_unlock;
1027 }
1028
1029 /* Store aib to get the current ETR status word. */
1030 BUG_ON(etr_stetr(&aib) != 0);
1031 etr_port0.esw = etr_port1.esw = aib.esw; /* Copy status word. */
1032 now = get_tod_clock();
1033
1034 /*
1035 * Update the port information if the last stepping port change
1036 * or data port change is older than 1.6 seconds.
1037 */
1038 if (now >= etr_tolec + (1600000 << 12))
1039 eacr = etr_handle_update(&aib, eacr);
1040
1041 /*
1042 * Select ports to enable. The preferred synchronization mode is PPS.
1043 * If a port can be enabled depends on a number of things:
1044 * 1) The port needs to be online and uptodate. A port is not
1045 * disabled just because it is not uptodate, but it is only
1046 * enabled if it is uptodate.
1047 * 2) The port needs to have the same mode (pps / etr).
1048 * 3) The port needs to be usable -> etr_port_valid() == 1
1049 * 4) To enable the second port the clock needs to be in sync.
1050 * 5) If both ports are useable and are ETR ports, the network id
1051 * has to be the same.
1052 * The eacr.sl bit is used to indicate etr mode vs. pps mode.
1053 */
1054 if (eacr.p0 && aib.esw.psc0 == etr_lpsc_pps_mode) {
1055 eacr.sl = 0;
1056 eacr.e0 = 1;
1057 if (!etr_mode_is_pps(etr_eacr))
1058 eacr.es = 0;
1059 if (!eacr.es || !eacr.p1 || aib.esw.psc1 != etr_lpsc_pps_mode)
1060 eacr.e1 = 0;
1061 // FIXME: uptodate checks ?
1062 else if (etr_port0_uptodate && etr_port1_uptodate)
1063 eacr.e1 = 1;
1064 sync_port = (etr_port0_uptodate &&
1065 etr_port_valid(&etr_port0, 0)) ? 0 : -1;
1066 } else if (eacr.p1 && aib.esw.psc1 == etr_lpsc_pps_mode) {
1067 eacr.sl = 0;
1068 eacr.e0 = 0;
1069 eacr.e1 = 1;
1070 if (!etr_mode_is_pps(etr_eacr))
1071 eacr.es = 0;
1072 sync_port = (etr_port1_uptodate &&
1073 etr_port_valid(&etr_port1, 1)) ? 1 : -1;
1074 } else if (eacr.p0 && aib.esw.psc0 == etr_lpsc_operational_step) {
1075 eacr.sl = 1;
1076 eacr.e0 = 1;
1077 if (!etr_mode_is_etr(etr_eacr))
1078 eacr.es = 0;
1079 if (!eacr.es || !eacr.p1 ||
1080 aib.esw.psc1 != etr_lpsc_operational_alt)
1081 eacr.e1 = 0;
1082 else if (etr_port0_uptodate && etr_port1_uptodate &&
1083 etr_compare_network(&etr_port0, &etr_port1))
1084 eacr.e1 = 1;
1085 sync_port = (etr_port0_uptodate &&
1086 etr_port_valid(&etr_port0, 0)) ? 0 : -1;
1087 } else if (eacr.p1 && aib.esw.psc1 == etr_lpsc_operational_step) {
1088 eacr.sl = 1;
1089 eacr.e0 = 0;
1090 eacr.e1 = 1;
1091 if (!etr_mode_is_etr(etr_eacr))
1092 eacr.es = 0;
1093 sync_port = (etr_port1_uptodate &&
1094 etr_port_valid(&etr_port1, 1)) ? 1 : -1;
1095 } else {
1096 /* Both ports not usable. */
1097 eacr.es = eacr.sl = 0;
1098 sync_port = -1;
1099 }
1100
1101 /*
1102 * If the clock is in sync just update the eacr and return.
1103 * If there is no valid sync port wait for a port update.
1104 */
1105 if ((eacr.es && check_sync_clock()) || sync_port < 0) {
1106 etr_update_eacr(eacr);
1107 etr_set_tolec_timeout(now);
1108 goto out_unlock;
1109 }
1110
1111 /*
1112 * Prepare control register for clock syncing
1113 * (reset data port bit, set sync check control.
1114 */
1115 eacr.dp = 0;
1116 eacr.es = 1;
1117
1118 /*
1119 * Update eacr and try to synchronize the clock. If the update
1120 * of eacr caused a stepping port switch (or if we have to
1121 * assume that a stepping port switch has occurred) or the
1122 * clock syncing failed, reset the sync check control bit
1123 * and set up a timer to try again after 0.5 seconds
1124 */
1125 etr_update_eacr(eacr);
1126 if (now < etr_tolec + (1600000 << 12) ||
1127 etr_sync_clock_stop(&aib, sync_port) != 0) {
1128 /* Sync failed. Try again in 1/2 second. */
1129 eacr.es = 0;
1130 etr_update_eacr(eacr);
1131 etr_set_sync_timeout();
1132 } else
1133 etr_set_tolec_timeout(now);
1134out_unlock:
1135 mutex_unlock(&etr_work_mutex);
1136}
1137
1138/*
1139 * Sysfs interface functions
1140 */
1141static struct bus_type etr_subsys = {
1142 .name = "etr",
1143 .dev_name = "etr",
1144};
1145
1146static struct device etr_port0_dev = {
1147 .id = 0,
1148 .bus = &etr_subsys,
1149};
1150
1151static struct device etr_port1_dev = {
1152 .id = 1,
1153 .bus = &etr_subsys,
1154};
1155
1156/*
1157 * ETR subsys attributes
1158 */
1159static ssize_t etr_stepping_port_show(struct device *dev,
1160 struct device_attribute *attr,
1161 char *buf)
1162{
1163 return sprintf(buf, "%i\n", etr_port0.esw.p);
1164}
1165
1166static DEVICE_ATTR(stepping_port, 0400, etr_stepping_port_show, NULL);
1167
1168static ssize_t etr_stepping_mode_show(struct device *dev,
1169 struct device_attribute *attr,
1170 char *buf)
1171{
1172 char *mode_str;
1173
1174 if (etr_mode_is_pps(etr_eacr))
1175 mode_str = "pps";
1176 else if (etr_mode_is_etr(etr_eacr))
1177 mode_str = "etr";
1178 else
1179 mode_str = "local";
1180 return sprintf(buf, "%s\n", mode_str);
1181}
1182
1183static DEVICE_ATTR(stepping_mode, 0400, etr_stepping_mode_show, NULL);
1184
1185/*
1186 * ETR port attributes
1187 */
1188static inline struct etr_aib *etr_aib_from_dev(struct device *dev)
1189{
1190 if (dev == &etr_port0_dev)
1191 return etr_port0_online ? &etr_port0 : NULL;
1192 else
1193 return etr_port1_online ? &etr_port1 : NULL;
1194}
1195
1196static ssize_t etr_online_show(struct device *dev,
1197 struct device_attribute *attr,
1198 char *buf)
1199{
1200 unsigned int online;
1201
1202 online = (dev == &etr_port0_dev) ? etr_port0_online : etr_port1_online;
1203 return sprintf(buf, "%i\n", online);
1204}
1205
1206static ssize_t etr_online_store(struct device *dev,
1207 struct device_attribute *attr,
1208 const char *buf, size_t count)
1209{
1210 unsigned int value;
1211
1212 value = simple_strtoul(buf, NULL, 0);
1213 if (value != 0 && value != 1)
1214 return -EINVAL;
1215 if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags))
1216 return -EOPNOTSUPP;
1217 mutex_lock(&clock_sync_mutex);
1218 if (dev == &etr_port0_dev) {
1219 if (etr_port0_online == value)
1220 goto out; /* Nothing to do. */
1221 etr_port0_online = value;
1222 if (etr_port0_online && etr_port1_online)
1223 set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
1224 else
1225 clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
1226 set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
1227 queue_work(time_sync_wq, &etr_work);
1228 } else {
1229 if (etr_port1_online == value)
1230 goto out; /* Nothing to do. */
1231 etr_port1_online = value;
1232 if (etr_port0_online && etr_port1_online)
1233 set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
1234 else
1235 clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
1236 set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
1237 queue_work(time_sync_wq, &etr_work);
1238 }
1239out:
1240 mutex_unlock(&clock_sync_mutex);
1241 return count;
1242}
1243
1244static DEVICE_ATTR(online, 0600, etr_online_show, etr_online_store);
1245
1246static ssize_t etr_stepping_control_show(struct device *dev,
1247 struct device_attribute *attr,
1248 char *buf)
1249{
1250 return sprintf(buf, "%i\n", (dev == &etr_port0_dev) ?
1251 etr_eacr.e0 : etr_eacr.e1);
1252}
1253
1254static DEVICE_ATTR(stepping_control, 0400, etr_stepping_control_show, NULL);
1255
1256static ssize_t etr_mode_code_show(struct device *dev,
1257 struct device_attribute *attr, char *buf)
1258{
1259 if (!etr_port0_online && !etr_port1_online)
1260 /* Status word is not uptodate if both ports are offline. */
1261 return -ENODATA;
1262 return sprintf(buf, "%i\n", (dev == &etr_port0_dev) ?
1263 etr_port0.esw.psc0 : etr_port0.esw.psc1);
1264}
1265
1266static DEVICE_ATTR(state_code, 0400, etr_mode_code_show, NULL);
1267
1268static ssize_t etr_untuned_show(struct device *dev,
1269 struct device_attribute *attr, char *buf)
1270{
1271 struct etr_aib *aib = etr_aib_from_dev(dev);
1272
1273 if (!aib || !aib->slsw.v1)
1274 return -ENODATA;
1275 return sprintf(buf, "%i\n", aib->edf1.u);
1276}
1277
1278static DEVICE_ATTR(untuned, 0400, etr_untuned_show, NULL);
1279
1280static ssize_t etr_network_id_show(struct device *dev,
1281 struct device_attribute *attr, char *buf)
1282{
1283 struct etr_aib *aib = etr_aib_from_dev(dev);
1284
1285 if (!aib || !aib->slsw.v1)
1286 return -ENODATA;
1287 return sprintf(buf, "%i\n", aib->edf1.net_id);
1288}
1289
1290static DEVICE_ATTR(network, 0400, etr_network_id_show, NULL);
1291
1292static ssize_t etr_id_show(struct device *dev,
1293 struct device_attribute *attr, char *buf)
1294{
1295 struct etr_aib *aib = etr_aib_from_dev(dev);
1296
1297 if (!aib || !aib->slsw.v1)
1298 return -ENODATA;
1299 return sprintf(buf, "%i\n", aib->edf1.etr_id);
1300}
1301
1302static DEVICE_ATTR(id, 0400, etr_id_show, NULL);
1303
1304static ssize_t etr_port_number_show(struct device *dev,
1305 struct device_attribute *attr, char *buf)
1306{
1307 struct etr_aib *aib = etr_aib_from_dev(dev);
1308
1309 if (!aib || !aib->slsw.v1)
1310 return -ENODATA;
1311 return sprintf(buf, "%i\n", aib->edf1.etr_pn);
1312}
1313
1314static DEVICE_ATTR(port, 0400, etr_port_number_show, NULL);
1315
1316static ssize_t etr_coupled_show(struct device *dev,
1317 struct device_attribute *attr, char *buf)
1318{
1319 struct etr_aib *aib = etr_aib_from_dev(dev);
1320
1321 if (!aib || !aib->slsw.v3)
1322 return -ENODATA;
1323 return sprintf(buf, "%i\n", aib->edf3.c);
1324}
1325
1326static DEVICE_ATTR(coupled, 0400, etr_coupled_show, NULL);
1327
1328static ssize_t etr_local_time_show(struct device *dev,
1329 struct device_attribute *attr, char *buf)
1330{
1331 struct etr_aib *aib = etr_aib_from_dev(dev);
1332
1333 if (!aib || !aib->slsw.v3)
1334 return -ENODATA;
1335 return sprintf(buf, "%i\n", aib->edf3.blto);
1336}
1337
1338static DEVICE_ATTR(local_time, 0400, etr_local_time_show, NULL);
1339
1340static ssize_t etr_utc_offset_show(struct device *dev,
1341 struct device_attribute *attr, char *buf)
1342{
1343 struct etr_aib *aib = etr_aib_from_dev(dev);
1344
1345 if (!aib || !aib->slsw.v3)
1346 return -ENODATA;
1347 return sprintf(buf, "%i\n", aib->edf3.buo);
1348}
1349
1350static DEVICE_ATTR(utc_offset, 0400, etr_utc_offset_show, NULL);
1351
1352static struct device_attribute *etr_port_attributes[] = {
1353 &dev_attr_online,
1354 &dev_attr_stepping_control,
1355 &dev_attr_state_code,
1356 &dev_attr_untuned,
1357 &dev_attr_network,
1358 &dev_attr_id,
1359 &dev_attr_port,
1360 &dev_attr_coupled,
1361 &dev_attr_local_time,
1362 &dev_attr_utc_offset,
1363 NULL
1364};
1365
1366static int __init etr_register_port(struct device *dev)
1367{
1368 struct device_attribute **attr;
1369 int rc;
1370
1371 rc = device_register(dev);
1372 if (rc)
1373 goto out;
1374 for (attr = etr_port_attributes; *attr; attr++) {
1375 rc = device_create_file(dev, *attr);
1376 if (rc)
1377 goto out_unreg;
1378 }
1379 return 0;
1380out_unreg:
1381 for (; attr >= etr_port_attributes; attr--)
1382 device_remove_file(dev, *attr);
1383 device_unregister(dev);
1384out:
1385 return rc;
1386}
1387
1388static void __init etr_unregister_port(struct device *dev)
1389{
1390 struct device_attribute **attr;
1391
1392 for (attr = etr_port_attributes; *attr; attr++)
1393 device_remove_file(dev, *attr);
1394 device_unregister(dev);
1395}
1396
1397static int __init etr_init_sysfs(void)
1398{
1399 int rc;
1400
1401 rc = subsys_system_register(&etr_subsys, NULL);
1402 if (rc)
1403 goto out;
1404 rc = device_create_file(etr_subsys.dev_root, &dev_attr_stepping_port);
1405 if (rc)
1406 goto out_unreg_subsys;
1407 rc = device_create_file(etr_subsys.dev_root, &dev_attr_stepping_mode);
1408 if (rc)
1409 goto out_remove_stepping_port;
1410 rc = etr_register_port(&etr_port0_dev);
1411 if (rc)
1412 goto out_remove_stepping_mode;
1413 rc = etr_register_port(&etr_port1_dev);
1414 if (rc)
1415 goto out_remove_port0;
1416 return 0;
1417
1418out_remove_port0:
1419 etr_unregister_port(&etr_port0_dev);
1420out_remove_stepping_mode:
1421 device_remove_file(etr_subsys.dev_root, &dev_attr_stepping_mode);
1422out_remove_stepping_port:
1423 device_remove_file(etr_subsys.dev_root, &dev_attr_stepping_port);
1424out_unreg_subsys:
1425 bus_unregister(&etr_subsys);
1426out:
1427 return rc;
1428}
1429
1430device_initcall(etr_init_sysfs);
1431
1432/*
1433 * Server Time Protocol (STP) code.
1434 */
1435static bool stp_online;
1436static struct stp_sstpi stp_info;
1437static void *stp_page;
1438
1439static void stp_work_fn(struct work_struct *work);
1440static DEFINE_MUTEX(stp_work_mutex);
1441static DECLARE_WORK(stp_work, stp_work_fn);
1442static struct timer_list stp_timer;
1443
1444static int __init early_parse_stp(char *p)
1445{
1446 return kstrtobool(p, &stp_online);
1447}
1448early_param("stp", early_parse_stp);
1449
1450/*
1451 * Reset STP attachment.
1452 */
1453static void __init stp_reset(void)
1454{
1455 int rc;
1456
1457 stp_page = (void *) get_zeroed_page(GFP_ATOMIC);
1458 rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000);
1459 if (rc == 0)
1460 set_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags);
1461 else if (stp_online) {
1462 pr_warn("The real or virtual hardware system does not provide an STP interface\n");
1463 free_page((unsigned long) stp_page);
1464 stp_page = NULL;
1465 stp_online = 0;
1466 }
1467}
1468
1469static void stp_timeout(unsigned long dummy)
1470{
1471 queue_work(time_sync_wq, &stp_work);
1472}
1473
1474static int __init stp_init(void)
1475{
1476 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
1477 return 0;
1478 setup_timer(&stp_timer, stp_timeout, 0UL);
1479 time_init_wq();
1480 if (!stp_online)
1481 return 0;
1482 queue_work(time_sync_wq, &stp_work);
1483 return 0;
1484}
1485
1486arch_initcall(stp_init);
1487
1488/*
1489 * STP timing alert. There are three causes:
1490 * 1) timing status change
1491 * 2) link availability change
1492 * 3) time control parameter change
1493 * In all three cases we are only interested in the clock source state.
1494 * If a STP clock source is now available use it.
1495 */
1496static void stp_timing_alert(struct stp_irq_parm *intparm)
1497{
1498 if (intparm->tsc || intparm->lac || intparm->tcpc)
1499 queue_work(time_sync_wq, &stp_work);
1500}
1501
1502/*
1503 * STP sync check machine check. This is called when the timing state
1504 * changes from the synchronized state to the unsynchronized state.
1505 * After a STP sync check the clock is not in sync. The machine check
1506 * is broadcasted to all cpus at the same time.
1507 */
1508int stp_sync_check(void)
1509{
1510 disable_sync_clock(NULL);
1511 return 1;
1512}
1513
1514/*
1515 * STP island condition machine check. This is called when an attached
1516 * server attempts to communicate over an STP link and the servers
1517 * have matching CTN ids and have a valid stratum-1 configuration
1518 * but the configurations do not match.
1519 */
1520int stp_island_check(void)
1521{
1522 disable_sync_clock(NULL);
1523 return 1;
1524}
1525
1526void stp_queue_work(void)
1527{
1528 queue_work(time_sync_wq, &stp_work);
1529}
1530
1531static int stp_sync_clock(void *data)
1532{
1533 static int first;
1534 unsigned long long old_clock, delta, new_clock, clock_delta;
1535 struct clock_sync_data *stp_sync;
1536 int rc;
1537
1538 stp_sync = data;
1539
1540 if (xchg(&first, 1) == 1) {
1541 /* Slave */
1542 clock_sync_cpu(stp_sync);
1543 return 0;
1544 }
1545
1546 /* Wait until all other cpus entered the sync function. */
1547 while (atomic_read(&stp_sync->cpus) != 0)
1548 cpu_relax();
1549
1550 enable_sync_clock();
1551
1552 rc = 0;
1553 if (stp_info.todoff[0] || stp_info.todoff[1] ||
1554 stp_info.todoff[2] || stp_info.todoff[3] ||
1555 stp_info.tmd != 2) {
1556 old_clock = get_tod_clock();
1557 rc = chsc_sstpc(stp_page, STP_OP_SYNC, 0);
1558 if (rc == 0) {
1559 new_clock = get_tod_clock();
1560 delta = adjust_time(old_clock, new_clock, 0);
1561 clock_delta = new_clock - old_clock;
1562 atomic_notifier_call_chain(&s390_epoch_delta_notifier,
1563 0, &clock_delta);
1564 fixup_clock_comparator(delta);
1565 rc = chsc_sstpi(stp_page, &stp_info,
1566 sizeof(struct stp_sstpi));
1567 if (rc == 0 && stp_info.tmd != 2)
1568 rc = -EAGAIN;
1569 }
1570 }
1571 if (rc) {
1572 disable_sync_clock(NULL);
1573 stp_sync->in_sync = -EAGAIN;
1574 } else
1575 stp_sync->in_sync = 1;
1576 xchg(&first, 0);
1577 return 0;
1578}
1579
1580/*
1581 * STP work. Check for the STP state and take over the clock
1582 * synchronization if the STP clock source is usable.
1583 */
1584static void stp_work_fn(struct work_struct *work)
1585{
1586 struct clock_sync_data stp_sync;
1587 int rc;
1588
1589 /* prevent multiple execution. */
1590 mutex_lock(&stp_work_mutex);
1591
1592 if (!stp_online) {
1593 chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000);
1594 del_timer_sync(&stp_timer);
1595 goto out_unlock;
1596 }
1597
1598 rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xb0e0);
1599 if (rc)
1600 goto out_unlock;
1601
1602 rc = chsc_sstpi(stp_page, &stp_info, sizeof(struct stp_sstpi));
1603 if (rc || stp_info.c == 0)
1604 goto out_unlock;
1605
1606 /* Skip synchronization if the clock is already in sync. */
1607 if (check_sync_clock())
1608 goto out_unlock;
1609
1610 memset(&stp_sync, 0, sizeof(stp_sync));
1611 get_online_cpus();
1612 atomic_set(&stp_sync.cpus, num_online_cpus() - 1);
1613 stop_machine(stp_sync_clock, &stp_sync, cpu_online_mask);
1614 put_online_cpus();
1615
1616 if (!check_sync_clock())
1617 /*
1618 * There is a usable clock but the synchonization failed.
1619 * Retry after a second.
1620 */
1621 mod_timer(&stp_timer, jiffies + HZ);
1622
1623out_unlock:
1624 mutex_unlock(&stp_work_mutex);
1625}
1626
1627/*
1628 * STP subsys sysfs interface functions
1629 */
1630static struct bus_type stp_subsys = {
1631 .name = "stp",
1632 .dev_name = "stp",
1633};
1634
1635static ssize_t stp_ctn_id_show(struct device *dev,
1636 struct device_attribute *attr,
1637 char *buf)
1638{
1639 if (!stp_online)
1640 return -ENODATA;
1641 return sprintf(buf, "%016llx\n",
1642 *(unsigned long long *) stp_info.ctnid);
1643}
1644
1645static DEVICE_ATTR(ctn_id, 0400, stp_ctn_id_show, NULL);
1646
1647static ssize_t stp_ctn_type_show(struct device *dev,
1648 struct device_attribute *attr,
1649 char *buf)
1650{
1651 if (!stp_online)
1652 return -ENODATA;
1653 return sprintf(buf, "%i\n", stp_info.ctn);
1654}
1655
1656static DEVICE_ATTR(ctn_type, 0400, stp_ctn_type_show, NULL);
1657
1658static ssize_t stp_dst_offset_show(struct device *dev,
1659 struct device_attribute *attr,
1660 char *buf)
1661{
1662 if (!stp_online || !(stp_info.vbits & 0x2000))
1663 return -ENODATA;
1664 return sprintf(buf, "%i\n", (int)(s16) stp_info.dsto);
1665}
1666
1667static DEVICE_ATTR(dst_offset, 0400, stp_dst_offset_show, NULL);
1668
1669static ssize_t stp_leap_seconds_show(struct device *dev,
1670 struct device_attribute *attr,
1671 char *buf)
1672{
1673 if (!stp_online || !(stp_info.vbits & 0x8000))
1674 return -ENODATA;
1675 return sprintf(buf, "%i\n", (int)(s16) stp_info.leaps);
1676}
1677
1678static DEVICE_ATTR(leap_seconds, 0400, stp_leap_seconds_show, NULL);
1679
1680static ssize_t stp_stratum_show(struct device *dev,
1681 struct device_attribute *attr,
1682 char *buf)
1683{
1684 if (!stp_online)
1685 return -ENODATA;
1686 return sprintf(buf, "%i\n", (int)(s16) stp_info.stratum);
1687}
1688
1689static DEVICE_ATTR(stratum, 0400, stp_stratum_show, NULL);
1690
1691static ssize_t stp_time_offset_show(struct device *dev,
1692 struct device_attribute *attr,
1693 char *buf)
1694{
1695 if (!stp_online || !(stp_info.vbits & 0x0800))
1696 return -ENODATA;
1697 return sprintf(buf, "%i\n", (int) stp_info.tto);
1698}
1699
1700static DEVICE_ATTR(time_offset, 0400, stp_time_offset_show, NULL);
1701
1702static ssize_t stp_time_zone_offset_show(struct device *dev,
1703 struct device_attribute *attr,
1704 char *buf)
1705{
1706 if (!stp_online || !(stp_info.vbits & 0x4000))
1707 return -ENODATA;
1708 return sprintf(buf, "%i\n", (int)(s16) stp_info.tzo);
1709}
1710
1711static DEVICE_ATTR(time_zone_offset, 0400,
1712 stp_time_zone_offset_show, NULL);
1713
1714static ssize_t stp_timing_mode_show(struct device *dev,
1715 struct device_attribute *attr,
1716 char *buf)
1717{
1718 if (!stp_online)
1719 return -ENODATA;
1720 return sprintf(buf, "%i\n", stp_info.tmd);
1721}
1722
1723static DEVICE_ATTR(timing_mode, 0400, stp_timing_mode_show, NULL);
1724
1725static ssize_t stp_timing_state_show(struct device *dev,
1726 struct device_attribute *attr,
1727 char *buf)
1728{
1729 if (!stp_online)
1730 return -ENODATA;
1731 return sprintf(buf, "%i\n", stp_info.tst);
1732}
1733
1734static DEVICE_ATTR(timing_state, 0400, stp_timing_state_show, NULL);
1735
1736static ssize_t stp_online_show(struct device *dev,
1737 struct device_attribute *attr,
1738 char *buf)
1739{
1740 return sprintf(buf, "%i\n", stp_online);
1741}
1742
1743static ssize_t stp_online_store(struct device *dev,
1744 struct device_attribute *attr,
1745 const char *buf, size_t count)
1746{
1747 unsigned int value;
1748
1749 value = simple_strtoul(buf, NULL, 0);
1750 if (value != 0 && value != 1)
1751 return -EINVAL;
1752 if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
1753 return -EOPNOTSUPP;
1754 mutex_lock(&clock_sync_mutex);
1755 stp_online = value;
1756 if (stp_online)
1757 set_bit(CLOCK_SYNC_STP, &clock_sync_flags);
1758 else
1759 clear_bit(CLOCK_SYNC_STP, &clock_sync_flags);
1760 queue_work(time_sync_wq, &stp_work);
1761 mutex_unlock(&clock_sync_mutex);
1762 return count;
1763}
1764
1765/*
1766 * Can't use DEVICE_ATTR because the attribute should be named
1767 * stp/online but dev_attr_online already exists in this file ..
1768 */
1769static struct device_attribute dev_attr_stp_online = {
1770 .attr = { .name = "online", .mode = 0600 },
1771 .show = stp_online_show,
1772 .store = stp_online_store,
1773};
1774
1775static struct device_attribute *stp_attributes[] = {
1776 &dev_attr_ctn_id,
1777 &dev_attr_ctn_type,
1778 &dev_attr_dst_offset,
1779 &dev_attr_leap_seconds,
1780 &dev_attr_stp_online,
1781 &dev_attr_stratum,
1782 &dev_attr_time_offset,
1783 &dev_attr_time_zone_offset,
1784 &dev_attr_timing_mode,
1785 &dev_attr_timing_state,
1786 NULL
1787};
1788
1789static int __init stp_init_sysfs(void)
1790{
1791 struct device_attribute **attr;
1792 int rc;
1793
1794 rc = subsys_system_register(&stp_subsys, NULL);
1795 if (rc)
1796 goto out;
1797 for (attr = stp_attributes; *attr; attr++) {
1798 rc = device_create_file(stp_subsys.dev_root, *attr);
1799 if (rc)
1800 goto out_unreg;
1801 }
1802 return 0;
1803out_unreg:
1804 for (; attr >= stp_attributes; attr--)
1805 device_remove_file(stp_subsys.dev_root, *attr);
1806 bus_unregister(&stp_subsys);
1807out:
1808 return rc;
1809}
1810
1811device_initcall(stp_init_sysfs);