xref: /openbmc/linux/arch/s390/kernel/time.c (revision ca55b2fe)
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 
56 u64 sched_clock_base_cc = -1;	/* Force to data section. */
57 EXPORT_SYMBOL_GPL(sched_clock_base_cc);
58 
59 static DEFINE_PER_CPU(struct clock_event_device, comparators);
60 
61 ATOMIC_NOTIFIER_HEAD(s390_epoch_delta_notifier);
62 EXPORT_SYMBOL(s390_epoch_delta_notifier);
63 
64 /*
65  * Scheduler clock - returns current time in nanosec units.
66  */
67 unsigned long long notrace sched_clock(void)
68 {
69 	return tod_to_ns(get_tod_clock_monotonic());
70 }
71 NOKPROBE_SYMBOL(sched_clock);
72 
73 /*
74  * Monotonic_clock - returns # of nanoseconds passed since time_init()
75  */
76 unsigned long long monotonic_clock(void)
77 {
78 	return sched_clock();
79 }
80 EXPORT_SYMBOL(monotonic_clock);
81 
82 void 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 }
92 EXPORT_SYMBOL(tod_to_timeval);
93 
94 void 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  */
106 static 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 
115 static 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  */
127 void 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 
156 static 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 
165 static void etr_timing_alert(struct etr_irq_parm *);
166 static void stp_timing_alert(struct stp_irq_parm *);
167 
168 static 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 *) &param32);
174 	if (param32 & 0x00038000)
175 		stp_timing_alert((struct stp_irq_parm *) &param32);
176 }
177 
178 static void etr_reset(void);
179 static void stp_reset(void);
180 
181 void read_persistent_clock64(struct timespec64 *ts)
182 {
183 	tod_to_timeval(get_tod_clock() - TOD_UNIX_EPOCH, ts);
184 }
185 
186 void read_boot_clock64(struct timespec64 *ts)
187 {
188 	tod_to_timeval(sched_clock_base_cc - TOD_UNIX_EPOCH, ts);
189 }
190 
191 static cycle_t read_tod_clock(struct clocksource *cs)
192 {
193 	return get_tod_clock();
194 }
195 
196 static 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 
206 struct clocksource * __init clocksource_default_clock(void)
207 {
208 	return &clocksource_tod;
209 }
210 
211 void 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 
252 extern struct timezone sys_tz;
253 
254 void 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  */
269 void __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  */
300 static 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 
330 static DEFINE_PER_CPU(atomic_t, clock_sync_word);
331 static DEFINE_MUTEX(clock_sync_mutex);
332 static 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  */
346 int 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 }
367 EXPORT_SYMBOL(get_sync_clock);
368 
369 /*
370  * Make get_sync_clock return -EAGAIN.
371  */
372 static 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  */
389 static 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  */
398 static 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 */
410 static struct workqueue_struct *time_sync_wq;
411 
412 static 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  */
422 static int etr_port0_online;
423 static int etr_port1_online;
424 static int etr_steai_available;
425 
426 static 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 }
438 early_param("etr", early_parse_etr);
439 
440 enum 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  */
473 static struct etr_eacr etr_eacr;
474 static u64 etr_tolec;			/* time of last eacr update */
475 static struct etr_aib etr_port0;
476 static int etr_port0_uptodate;
477 static struct etr_aib etr_port1;
478 static int etr_port1_uptodate;
479 static unsigned long etr_events;
480 static struct timer_list etr_timer;
481 
482 static void etr_timeout(unsigned long dummy);
483 static void etr_work_fn(struct work_struct *work);
484 static DEFINE_MUTEX(etr_work_mutex);
485 static DECLARE_WORK(etr_work, etr_work_fn);
486 
487 /*
488  * Reset ETR attachment.
489  */
490 static 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_warning("The real or virtual hardware system does "
503 			   "not provide an ETR interface\n");
504 		etr_port0_online = etr_port1_online = 0;
505 	}
506 }
507 
508 static int __init etr_init(void)
509 {
510 	struct etr_aib aib;
511 
512 	if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags))
513 		return 0;
514 	time_init_wq();
515 	/* Check if this machine has the steai instruction. */
516 	if (etr_steai(&aib, ETR_STEAI_STEPPING_PORT) == 0)
517 		etr_steai_available = 1;
518 	setup_timer(&etr_timer, etr_timeout, 0UL);
519 	if (etr_port0_online) {
520 		set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
521 		queue_work(time_sync_wq, &etr_work);
522 	}
523 	if (etr_port1_online) {
524 		set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
525 		queue_work(time_sync_wq, &etr_work);
526 	}
527 	return 0;
528 }
529 
530 arch_initcall(etr_init);
531 
532 /*
533  * Two sorts of ETR machine checks. The architecture reads:
534  * "When a machine-check niterruption occurs and if a switch-to-local or
535  *  ETR-sync-check interrupt request is pending but disabled, this pending
536  *  disabled interruption request is indicated and is cleared".
537  * Which means that we can get etr_switch_to_local events from the machine
538  * check handler although the interruption condition is disabled. Lovely..
539  */
540 
541 /*
542  * Switch to local machine check. This is called when the last usable
543  * ETR port goes inactive. After switch to local the clock is not in sync.
544  */
545 void etr_switch_to_local(void)
546 {
547 	if (!etr_eacr.sl)
548 		return;
549 	disable_sync_clock(NULL);
550 	if (!test_and_set_bit(ETR_EVENT_SWITCH_LOCAL, &etr_events)) {
551 		etr_eacr.es = etr_eacr.sl = 0;
552 		etr_setr(&etr_eacr);
553 		queue_work(time_sync_wq, &etr_work);
554 	}
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  */
563 void etr_sync_check(void)
564 {
565 	if (!etr_eacr.es)
566 		return;
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 		queue_work(time_sync_wq, &etr_work);
572 	}
573 }
574 
575 /*
576  * ETR timing alert. There are two causes:
577  * 1) port state change, check the usability of the port
578  * 2) port alert, one of the ETR-data-validity bits (v1-v2 bits of the
579  *    sldr-status word) or ETR-data word 1 (edf1) or ETR-data word 3 (edf3)
580  *    or ETR-data word 4 (edf4) has changed.
581  */
582 static void etr_timing_alert(struct etr_irq_parm *intparm)
583 {
584 	if (intparm->pc0)
585 		/* ETR port 0 state change. */
586 		set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
587 	if (intparm->pc1)
588 		/* ETR port 1 state change. */
589 		set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
590 	if (intparm->eai)
591 		/*
592 		 * ETR port alert on either port 0, 1 or both.
593 		 * Both ports are not up-to-date now.
594 		 */
595 		set_bit(ETR_EVENT_PORT_ALERT, &etr_events);
596 	queue_work(time_sync_wq, &etr_work);
597 }
598 
599 static void etr_timeout(unsigned long dummy)
600 {
601 	set_bit(ETR_EVENT_UPDATE, &etr_events);
602 	queue_work(time_sync_wq, &etr_work);
603 }
604 
605 /*
606  * Check if the etr mode is pss.
607  */
608 static inline int etr_mode_is_pps(struct etr_eacr eacr)
609 {
610 	return eacr.es && !eacr.sl;
611 }
612 
613 /*
614  * Check if the etr mode is etr.
615  */
616 static inline int etr_mode_is_etr(struct etr_eacr eacr)
617 {
618 	return eacr.es && eacr.sl;
619 }
620 
621 /*
622  * Check if the port can be used for TOD synchronization.
623  * For PPS mode the port has to receive OTEs. For ETR mode
624  * the port has to receive OTEs, the ETR stepping bit has to
625  * be zero and the validity bits for data frame 1, 2, and 3
626  * have to be 1.
627  */
628 static int etr_port_valid(struct etr_aib *aib, int port)
629 {
630 	unsigned int psc;
631 
632 	/* Check that this port is receiving OTEs. */
633 	if (aib->tsp == 0)
634 		return 0;
635 
636 	psc = port ? aib->esw.psc1 : aib->esw.psc0;
637 	if (psc == etr_lpsc_pps_mode)
638 		return 1;
639 	if (psc == etr_lpsc_operational_step)
640 		return !aib->esw.y && aib->slsw.v1 &&
641 			aib->slsw.v2 && aib->slsw.v3;
642 	return 0;
643 }
644 
645 /*
646  * Check if two ports are on the same network.
647  */
648 static int etr_compare_network(struct etr_aib *aib1, struct etr_aib *aib2)
649 {
650 	// FIXME: any other fields we have to compare?
651 	return aib1->edf1.net_id == aib2->edf1.net_id;
652 }
653 
654 /*
655  * Wrapper for etr_stei that converts physical port states
656  * to logical port states to be consistent with the output
657  * of stetr (see etr_psc vs. etr_lpsc).
658  */
659 static void etr_steai_cv(struct etr_aib *aib, unsigned int func)
660 {
661 	BUG_ON(etr_steai(aib, func) != 0);
662 	/* Convert port state to logical port state. */
663 	if (aib->esw.psc0 == 1)
664 		aib->esw.psc0 = 2;
665 	else if (aib->esw.psc0 == 0 && aib->esw.p == 0)
666 		aib->esw.psc0 = 1;
667 	if (aib->esw.psc1 == 1)
668 		aib->esw.psc1 = 2;
669 	else if (aib->esw.psc1 == 0 && aib->esw.p == 1)
670 		aib->esw.psc1 = 1;
671 }
672 
673 /*
674  * Check if the aib a2 is still connected to the same attachment as
675  * aib a1, the etv values differ by one and a2 is valid.
676  */
677 static int etr_aib_follows(struct etr_aib *a1, struct etr_aib *a2, int p)
678 {
679 	int state_a1, state_a2;
680 
681 	/* Paranoia check: e0/e1 should better be the same. */
682 	if (a1->esw.eacr.e0 != a2->esw.eacr.e0 ||
683 	    a1->esw.eacr.e1 != a2->esw.eacr.e1)
684 		return 0;
685 
686 	/* Still connected to the same etr ? */
687 	state_a1 = p ? a1->esw.psc1 : a1->esw.psc0;
688 	state_a2 = p ? a2->esw.psc1 : a2->esw.psc0;
689 	if (state_a1 == etr_lpsc_operational_step) {
690 		if (state_a2 != etr_lpsc_operational_step ||
691 		    a1->edf1.net_id != a2->edf1.net_id ||
692 		    a1->edf1.etr_id != a2->edf1.etr_id ||
693 		    a1->edf1.etr_pn != a2->edf1.etr_pn)
694 			return 0;
695 	} else if (state_a2 != etr_lpsc_pps_mode)
696 		return 0;
697 
698 	/* The ETV value of a2 needs to be ETV of a1 + 1. */
699 	if (a1->edf2.etv + 1 != a2->edf2.etv)
700 		return 0;
701 
702 	if (!etr_port_valid(a2, p))
703 		return 0;
704 
705 	return 1;
706 }
707 
708 struct clock_sync_data {
709 	atomic_t cpus;
710 	int in_sync;
711 	unsigned long long fixup_cc;
712 	int etr_port;
713 	struct etr_aib *etr_aib;
714 };
715 
716 static void clock_sync_cpu(struct clock_sync_data *sync)
717 {
718 	atomic_dec(&sync->cpus);
719 	enable_sync_clock();
720 	/*
721 	 * This looks like a busy wait loop but it isn't. etr_sync_cpus
722 	 * is called on all other cpus while the TOD clocks is stopped.
723 	 * __udelay will stop the cpu on an enabled wait psw until the
724 	 * TOD is running again.
725 	 */
726 	while (sync->in_sync == 0) {
727 		__udelay(1);
728 		/*
729 		 * A different cpu changes *in_sync. Therefore use
730 		 * barrier() to force memory access.
731 		 */
732 		barrier();
733 	}
734 	if (sync->in_sync != 1)
735 		/* Didn't work. Clear per-cpu in sync bit again. */
736 		disable_sync_clock(NULL);
737 	/*
738 	 * This round of TOD syncing is done. Set the clock comparator
739 	 * to the next tick and let the processor continue.
740 	 */
741 	fixup_clock_comparator(sync->fixup_cc);
742 }
743 
744 /*
745  * Sync the TOD clock using the port referred to by aibp. This port
746  * has to be enabled and the other port has to be disabled. The
747  * last eacr update has to be more than 1.6 seconds in the past.
748  */
749 static int etr_sync_clock(void *data)
750 {
751 	static int first;
752 	unsigned long long clock, old_clock, clock_delta, delay, delta;
753 	struct clock_sync_data *etr_sync;
754 	struct etr_aib *sync_port, *aib;
755 	int port;
756 	int rc;
757 
758 	etr_sync = data;
759 
760 	if (xchg(&first, 1) == 1) {
761 		/* Slave */
762 		clock_sync_cpu(etr_sync);
763 		return 0;
764 	}
765 
766 	/* Wait until all other cpus entered the sync function. */
767 	while (atomic_read(&etr_sync->cpus) != 0)
768 		cpu_relax();
769 
770 	port = etr_sync->etr_port;
771 	aib = etr_sync->etr_aib;
772 	sync_port = (port == 0) ? &etr_port0 : &etr_port1;
773 	enable_sync_clock();
774 
775 	/* Set clock to next OTE. */
776 	__ctl_set_bit(14, 21);
777 	__ctl_set_bit(0, 29);
778 	clock = ((unsigned long long) (aib->edf2.etv + 1)) << 32;
779 	old_clock = get_tod_clock();
780 	if (set_tod_clock(clock) == 0) {
781 		__udelay(1);	/* Wait for the clock to start. */
782 		__ctl_clear_bit(0, 29);
783 		__ctl_clear_bit(14, 21);
784 		etr_stetr(aib);
785 		/* Adjust Linux timing variables. */
786 		delay = (unsigned long long)
787 			(aib->edf2.etv - sync_port->edf2.etv) << 32;
788 		delta = adjust_time(old_clock, clock, delay);
789 		clock_delta = clock - old_clock;
790 		atomic_notifier_call_chain(&s390_epoch_delta_notifier, 0,
791 					   &clock_delta);
792 		etr_sync->fixup_cc = delta;
793 		fixup_clock_comparator(delta);
794 		/* Verify that the clock is properly set. */
795 		if (!etr_aib_follows(sync_port, aib, port)) {
796 			/* Didn't work. */
797 			disable_sync_clock(NULL);
798 			etr_sync->in_sync = -EAGAIN;
799 			rc = -EAGAIN;
800 		} else {
801 			etr_sync->in_sync = 1;
802 			rc = 0;
803 		}
804 	} else {
805 		/* Could not set the clock ?!? */
806 		__ctl_clear_bit(0, 29);
807 		__ctl_clear_bit(14, 21);
808 		disable_sync_clock(NULL);
809 		etr_sync->in_sync = -EAGAIN;
810 		rc = -EAGAIN;
811 	}
812 	xchg(&first, 0);
813 	return rc;
814 }
815 
816 static int etr_sync_clock_stop(struct etr_aib *aib, int port)
817 {
818 	struct clock_sync_data etr_sync;
819 	struct etr_aib *sync_port;
820 	int follows;
821 	int rc;
822 
823 	/* Check if the current aib is adjacent to the sync port aib. */
824 	sync_port = (port == 0) ? &etr_port0 : &etr_port1;
825 	follows = etr_aib_follows(sync_port, aib, port);
826 	memcpy(sync_port, aib, sizeof(*aib));
827 	if (!follows)
828 		return -EAGAIN;
829 	memset(&etr_sync, 0, sizeof(etr_sync));
830 	etr_sync.etr_aib = aib;
831 	etr_sync.etr_port = port;
832 	get_online_cpus();
833 	atomic_set(&etr_sync.cpus, num_online_cpus() - 1);
834 	rc = stop_machine(etr_sync_clock, &etr_sync, cpu_online_mask);
835 	put_online_cpus();
836 	return rc;
837 }
838 
839 /*
840  * Handle the immediate effects of the different events.
841  * The port change event is used for online/offline changes.
842  */
843 static struct etr_eacr etr_handle_events(struct etr_eacr eacr)
844 {
845 	if (test_and_clear_bit(ETR_EVENT_SYNC_CHECK, &etr_events))
846 		eacr.es = 0;
847 	if (test_and_clear_bit(ETR_EVENT_SWITCH_LOCAL, &etr_events))
848 		eacr.es = eacr.sl = 0;
849 	if (test_and_clear_bit(ETR_EVENT_PORT_ALERT, &etr_events))
850 		etr_port0_uptodate = etr_port1_uptodate = 0;
851 
852 	if (test_and_clear_bit(ETR_EVENT_PORT0_CHANGE, &etr_events)) {
853 		if (eacr.e0)
854 			/*
855 			 * Port change of an enabled port. We have to
856 			 * assume that this can have caused an stepping
857 			 * port switch.
858 			 */
859 			etr_tolec = get_tod_clock();
860 		eacr.p0 = etr_port0_online;
861 		if (!eacr.p0)
862 			eacr.e0 = 0;
863 		etr_port0_uptodate = 0;
864 	}
865 	if (test_and_clear_bit(ETR_EVENT_PORT1_CHANGE, &etr_events)) {
866 		if (eacr.e1)
867 			/*
868 			 * Port change of an enabled port. We have to
869 			 * assume that this can have caused an stepping
870 			 * port switch.
871 			 */
872 			etr_tolec = get_tod_clock();
873 		eacr.p1 = etr_port1_online;
874 		if (!eacr.p1)
875 			eacr.e1 = 0;
876 		etr_port1_uptodate = 0;
877 	}
878 	clear_bit(ETR_EVENT_UPDATE, &etr_events);
879 	return eacr;
880 }
881 
882 /*
883  * Set up a timer that expires after the etr_tolec + 1.6 seconds if
884  * one of the ports needs an update.
885  */
886 static void etr_set_tolec_timeout(unsigned long long now)
887 {
888 	unsigned long micros;
889 
890 	if ((!etr_eacr.p0 || etr_port0_uptodate) &&
891 	    (!etr_eacr.p1 || etr_port1_uptodate))
892 		return;
893 	micros = (now > etr_tolec) ? ((now - etr_tolec) >> 12) : 0;
894 	micros = (micros > 1600000) ? 0 : 1600000 - micros;
895 	mod_timer(&etr_timer, jiffies + (micros * HZ) / 1000000 + 1);
896 }
897 
898 /*
899  * Set up a time that expires after 1/2 second.
900  */
901 static void etr_set_sync_timeout(void)
902 {
903 	mod_timer(&etr_timer, jiffies + HZ/2);
904 }
905 
906 /*
907  * Update the aib information for one or both ports.
908  */
909 static struct etr_eacr etr_handle_update(struct etr_aib *aib,
910 					 struct etr_eacr eacr)
911 {
912 	/* With both ports disabled the aib information is useless. */
913 	if (!eacr.e0 && !eacr.e1)
914 		return eacr;
915 
916 	/* Update port0 or port1 with aib stored in etr_work_fn. */
917 	if (aib->esw.q == 0) {
918 		/* Information for port 0 stored. */
919 		if (eacr.p0 && !etr_port0_uptodate) {
920 			etr_port0 = *aib;
921 			if (etr_port0_online)
922 				etr_port0_uptodate = 1;
923 		}
924 	} else {
925 		/* Information for port 1 stored. */
926 		if (eacr.p1 && !etr_port1_uptodate) {
927 			etr_port1 = *aib;
928 			if (etr_port0_online)
929 				etr_port1_uptodate = 1;
930 		}
931 	}
932 
933 	/*
934 	 * Do not try to get the alternate port aib if the clock
935 	 * is not in sync yet.
936 	 */
937 	if (!eacr.es || !check_sync_clock())
938 		return eacr;
939 
940 	/*
941 	 * If steai is available we can get the information about
942 	 * the other port immediately. If only stetr is available the
943 	 * data-port bit toggle has to be used.
944 	 */
945 	if (etr_steai_available) {
946 		if (eacr.p0 && !etr_port0_uptodate) {
947 			etr_steai_cv(&etr_port0, ETR_STEAI_PORT_0);
948 			etr_port0_uptodate = 1;
949 		}
950 		if (eacr.p1 && !etr_port1_uptodate) {
951 			etr_steai_cv(&etr_port1, ETR_STEAI_PORT_1);
952 			etr_port1_uptodate = 1;
953 		}
954 	} else {
955 		/*
956 		 * One port was updated above, if the other
957 		 * port is not uptodate toggle dp bit.
958 		 */
959 		if ((eacr.p0 && !etr_port0_uptodate) ||
960 		    (eacr.p1 && !etr_port1_uptodate))
961 			eacr.dp ^= 1;
962 		else
963 			eacr.dp = 0;
964 	}
965 	return eacr;
966 }
967 
968 /*
969  * Write new etr control register if it differs from the current one.
970  * Return 1 if etr_tolec has been updated as well.
971  */
972 static void etr_update_eacr(struct etr_eacr eacr)
973 {
974 	int dp_changed;
975 
976 	if (memcmp(&etr_eacr, &eacr, sizeof(eacr)) == 0)
977 		/* No change, return. */
978 		return;
979 	/*
980 	 * The disable of an active port of the change of the data port
981 	 * bit can/will cause a change in the data port.
982 	 */
983 	dp_changed = etr_eacr.e0 > eacr.e0 || etr_eacr.e1 > eacr.e1 ||
984 		(etr_eacr.dp ^ eacr.dp) != 0;
985 	etr_eacr = eacr;
986 	etr_setr(&etr_eacr);
987 	if (dp_changed)
988 		etr_tolec = get_tod_clock();
989 }
990 
991 /*
992  * ETR work. In this function you'll find the main logic. In
993  * particular this is the only function that calls etr_update_eacr(),
994  * it "controls" the etr control register.
995  */
996 static void etr_work_fn(struct work_struct *work)
997 {
998 	unsigned long long now;
999 	struct etr_eacr eacr;
1000 	struct etr_aib aib;
1001 	int sync_port;
1002 
1003 	/* prevent multiple execution. */
1004 	mutex_lock(&etr_work_mutex);
1005 
1006 	/* Create working copy of etr_eacr. */
1007 	eacr = etr_eacr;
1008 
1009 	/* Check for the different events and their immediate effects. */
1010 	eacr = etr_handle_events(eacr);
1011 
1012 	/* Check if ETR is supposed to be active. */
1013 	eacr.ea = eacr.p0 || eacr.p1;
1014 	if (!eacr.ea) {
1015 		/* Both ports offline. Reset everything. */
1016 		eacr.dp = eacr.es = eacr.sl = 0;
1017 		on_each_cpu(disable_sync_clock, NULL, 1);
1018 		del_timer_sync(&etr_timer);
1019 		etr_update_eacr(eacr);
1020 		goto out_unlock;
1021 	}
1022 
1023 	/* Store aib to get the current ETR status word. */
1024 	BUG_ON(etr_stetr(&aib) != 0);
1025 	etr_port0.esw = etr_port1.esw = aib.esw;	/* Copy status word. */
1026 	now = get_tod_clock();
1027 
1028 	/*
1029 	 * Update the port information if the last stepping port change
1030 	 * or data port change is older than 1.6 seconds.
1031 	 */
1032 	if (now >= etr_tolec + (1600000 << 12))
1033 		eacr = etr_handle_update(&aib, eacr);
1034 
1035 	/*
1036 	 * Select ports to enable. The preferred synchronization mode is PPS.
1037 	 * If a port can be enabled depends on a number of things:
1038 	 * 1) The port needs to be online and uptodate. A port is not
1039 	 *    disabled just because it is not uptodate, but it is only
1040 	 *    enabled if it is uptodate.
1041 	 * 2) The port needs to have the same mode (pps / etr).
1042 	 * 3) The port needs to be usable -> etr_port_valid() == 1
1043 	 * 4) To enable the second port the clock needs to be in sync.
1044 	 * 5) If both ports are useable and are ETR ports, the network id
1045 	 *    has to be the same.
1046 	 * The eacr.sl bit is used to indicate etr mode vs. pps mode.
1047 	 */
1048 	if (eacr.p0 && aib.esw.psc0 == etr_lpsc_pps_mode) {
1049 		eacr.sl = 0;
1050 		eacr.e0 = 1;
1051 		if (!etr_mode_is_pps(etr_eacr))
1052 			eacr.es = 0;
1053 		if (!eacr.es || !eacr.p1 || aib.esw.psc1 != etr_lpsc_pps_mode)
1054 			eacr.e1 = 0;
1055 		// FIXME: uptodate checks ?
1056 		else if (etr_port0_uptodate && etr_port1_uptodate)
1057 			eacr.e1 = 1;
1058 		sync_port = (etr_port0_uptodate &&
1059 			     etr_port_valid(&etr_port0, 0)) ? 0 : -1;
1060 	} else if (eacr.p1 && aib.esw.psc1 == etr_lpsc_pps_mode) {
1061 		eacr.sl = 0;
1062 		eacr.e0 = 0;
1063 		eacr.e1 = 1;
1064 		if (!etr_mode_is_pps(etr_eacr))
1065 			eacr.es = 0;
1066 		sync_port = (etr_port1_uptodate &&
1067 			     etr_port_valid(&etr_port1, 1)) ? 1 : -1;
1068 	} else if (eacr.p0 && aib.esw.psc0 == etr_lpsc_operational_step) {
1069 		eacr.sl = 1;
1070 		eacr.e0 = 1;
1071 		if (!etr_mode_is_etr(etr_eacr))
1072 			eacr.es = 0;
1073 		if (!eacr.es || !eacr.p1 ||
1074 		    aib.esw.psc1 != etr_lpsc_operational_alt)
1075 			eacr.e1 = 0;
1076 		else if (etr_port0_uptodate && etr_port1_uptodate &&
1077 			 etr_compare_network(&etr_port0, &etr_port1))
1078 			eacr.e1 = 1;
1079 		sync_port = (etr_port0_uptodate &&
1080 			     etr_port_valid(&etr_port0, 0)) ? 0 : -1;
1081 	} else if (eacr.p1 && aib.esw.psc1 == etr_lpsc_operational_step) {
1082 		eacr.sl = 1;
1083 		eacr.e0 = 0;
1084 		eacr.e1 = 1;
1085 		if (!etr_mode_is_etr(etr_eacr))
1086 			eacr.es = 0;
1087 		sync_port = (etr_port1_uptodate &&
1088 			     etr_port_valid(&etr_port1, 1)) ? 1 : -1;
1089 	} else {
1090 		/* Both ports not usable. */
1091 		eacr.es = eacr.sl = 0;
1092 		sync_port = -1;
1093 	}
1094 
1095 	/*
1096 	 * If the clock is in sync just update the eacr and return.
1097 	 * If there is no valid sync port wait for a port update.
1098 	 */
1099 	if ((eacr.es && check_sync_clock()) || sync_port < 0) {
1100 		etr_update_eacr(eacr);
1101 		etr_set_tolec_timeout(now);
1102 		goto out_unlock;
1103 	}
1104 
1105 	/*
1106 	 * Prepare control register for clock syncing
1107 	 * (reset data port bit, set sync check control.
1108 	 */
1109 	eacr.dp = 0;
1110 	eacr.es = 1;
1111 
1112 	/*
1113 	 * Update eacr and try to synchronize the clock. If the update
1114 	 * of eacr caused a stepping port switch (or if we have to
1115 	 * assume that a stepping port switch has occurred) or the
1116 	 * clock syncing failed, reset the sync check control bit
1117 	 * and set up a timer to try again after 0.5 seconds
1118 	 */
1119 	etr_update_eacr(eacr);
1120 	if (now < etr_tolec + (1600000 << 12) ||
1121 	    etr_sync_clock_stop(&aib, sync_port) != 0) {
1122 		/* Sync failed. Try again in 1/2 second. */
1123 		eacr.es = 0;
1124 		etr_update_eacr(eacr);
1125 		etr_set_sync_timeout();
1126 	} else
1127 		etr_set_tolec_timeout(now);
1128 out_unlock:
1129 	mutex_unlock(&etr_work_mutex);
1130 }
1131 
1132 /*
1133  * Sysfs interface functions
1134  */
1135 static struct bus_type etr_subsys = {
1136 	.name		= "etr",
1137 	.dev_name	= "etr",
1138 };
1139 
1140 static struct device etr_port0_dev = {
1141 	.id	= 0,
1142 	.bus	= &etr_subsys,
1143 };
1144 
1145 static struct device etr_port1_dev = {
1146 	.id	= 1,
1147 	.bus	= &etr_subsys,
1148 };
1149 
1150 /*
1151  * ETR subsys attributes
1152  */
1153 static ssize_t etr_stepping_port_show(struct device *dev,
1154 					struct device_attribute *attr,
1155 					char *buf)
1156 {
1157 	return sprintf(buf, "%i\n", etr_port0.esw.p);
1158 }
1159 
1160 static DEVICE_ATTR(stepping_port, 0400, etr_stepping_port_show, NULL);
1161 
1162 static ssize_t etr_stepping_mode_show(struct device *dev,
1163 					struct device_attribute *attr,
1164 					char *buf)
1165 {
1166 	char *mode_str;
1167 
1168 	if (etr_mode_is_pps(etr_eacr))
1169 		mode_str = "pps";
1170 	else if (etr_mode_is_etr(etr_eacr))
1171 		mode_str = "etr";
1172 	else
1173 		mode_str = "local";
1174 	return sprintf(buf, "%s\n", mode_str);
1175 }
1176 
1177 static DEVICE_ATTR(stepping_mode, 0400, etr_stepping_mode_show, NULL);
1178 
1179 /*
1180  * ETR port attributes
1181  */
1182 static inline struct etr_aib *etr_aib_from_dev(struct device *dev)
1183 {
1184 	if (dev == &etr_port0_dev)
1185 		return etr_port0_online ? &etr_port0 : NULL;
1186 	else
1187 		return etr_port1_online ? &etr_port1 : NULL;
1188 }
1189 
1190 static ssize_t etr_online_show(struct device *dev,
1191 				struct device_attribute *attr,
1192 				char *buf)
1193 {
1194 	unsigned int online;
1195 
1196 	online = (dev == &etr_port0_dev) ? etr_port0_online : etr_port1_online;
1197 	return sprintf(buf, "%i\n", online);
1198 }
1199 
1200 static ssize_t etr_online_store(struct device *dev,
1201 				struct device_attribute *attr,
1202 				const char *buf, size_t count)
1203 {
1204 	unsigned int value;
1205 
1206 	value = simple_strtoul(buf, NULL, 0);
1207 	if (value != 0 && value != 1)
1208 		return -EINVAL;
1209 	if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags))
1210 		return -EOPNOTSUPP;
1211 	mutex_lock(&clock_sync_mutex);
1212 	if (dev == &etr_port0_dev) {
1213 		if (etr_port0_online == value)
1214 			goto out;	/* Nothing to do. */
1215 		etr_port0_online = value;
1216 		if (etr_port0_online && etr_port1_online)
1217 			set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
1218 		else
1219 			clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
1220 		set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
1221 		queue_work(time_sync_wq, &etr_work);
1222 	} else {
1223 		if (etr_port1_online == value)
1224 			goto out;	/* Nothing to do. */
1225 		etr_port1_online = value;
1226 		if (etr_port0_online && etr_port1_online)
1227 			set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
1228 		else
1229 			clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
1230 		set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
1231 		queue_work(time_sync_wq, &etr_work);
1232 	}
1233 out:
1234 	mutex_unlock(&clock_sync_mutex);
1235 	return count;
1236 }
1237 
1238 static DEVICE_ATTR(online, 0600, etr_online_show, etr_online_store);
1239 
1240 static ssize_t etr_stepping_control_show(struct device *dev,
1241 					struct device_attribute *attr,
1242 					char *buf)
1243 {
1244 	return sprintf(buf, "%i\n", (dev == &etr_port0_dev) ?
1245 		       etr_eacr.e0 : etr_eacr.e1);
1246 }
1247 
1248 static DEVICE_ATTR(stepping_control, 0400, etr_stepping_control_show, NULL);
1249 
1250 static ssize_t etr_mode_code_show(struct device *dev,
1251 				struct device_attribute *attr, char *buf)
1252 {
1253 	if (!etr_port0_online && !etr_port1_online)
1254 		/* Status word is not uptodate if both ports are offline. */
1255 		return -ENODATA;
1256 	return sprintf(buf, "%i\n", (dev == &etr_port0_dev) ?
1257 		       etr_port0.esw.psc0 : etr_port0.esw.psc1);
1258 }
1259 
1260 static DEVICE_ATTR(state_code, 0400, etr_mode_code_show, NULL);
1261 
1262 static ssize_t etr_untuned_show(struct device *dev,
1263 				struct device_attribute *attr, char *buf)
1264 {
1265 	struct etr_aib *aib = etr_aib_from_dev(dev);
1266 
1267 	if (!aib || !aib->slsw.v1)
1268 		return -ENODATA;
1269 	return sprintf(buf, "%i\n", aib->edf1.u);
1270 }
1271 
1272 static DEVICE_ATTR(untuned, 0400, etr_untuned_show, NULL);
1273 
1274 static ssize_t etr_network_id_show(struct device *dev,
1275 				struct device_attribute *attr, char *buf)
1276 {
1277 	struct etr_aib *aib = etr_aib_from_dev(dev);
1278 
1279 	if (!aib || !aib->slsw.v1)
1280 		return -ENODATA;
1281 	return sprintf(buf, "%i\n", aib->edf1.net_id);
1282 }
1283 
1284 static DEVICE_ATTR(network, 0400, etr_network_id_show, NULL);
1285 
1286 static ssize_t etr_id_show(struct device *dev,
1287 			struct device_attribute *attr, char *buf)
1288 {
1289 	struct etr_aib *aib = etr_aib_from_dev(dev);
1290 
1291 	if (!aib || !aib->slsw.v1)
1292 		return -ENODATA;
1293 	return sprintf(buf, "%i\n", aib->edf1.etr_id);
1294 }
1295 
1296 static DEVICE_ATTR(id, 0400, etr_id_show, NULL);
1297 
1298 static ssize_t etr_port_number_show(struct device *dev,
1299 			struct device_attribute *attr, char *buf)
1300 {
1301 	struct etr_aib *aib = etr_aib_from_dev(dev);
1302 
1303 	if (!aib || !aib->slsw.v1)
1304 		return -ENODATA;
1305 	return sprintf(buf, "%i\n", aib->edf1.etr_pn);
1306 }
1307 
1308 static DEVICE_ATTR(port, 0400, etr_port_number_show, NULL);
1309 
1310 static ssize_t etr_coupled_show(struct device *dev,
1311 			struct device_attribute *attr, char *buf)
1312 {
1313 	struct etr_aib *aib = etr_aib_from_dev(dev);
1314 
1315 	if (!aib || !aib->slsw.v3)
1316 		return -ENODATA;
1317 	return sprintf(buf, "%i\n", aib->edf3.c);
1318 }
1319 
1320 static DEVICE_ATTR(coupled, 0400, etr_coupled_show, NULL);
1321 
1322 static ssize_t etr_local_time_show(struct device *dev,
1323 			struct device_attribute *attr, char *buf)
1324 {
1325 	struct etr_aib *aib = etr_aib_from_dev(dev);
1326 
1327 	if (!aib || !aib->slsw.v3)
1328 		return -ENODATA;
1329 	return sprintf(buf, "%i\n", aib->edf3.blto);
1330 }
1331 
1332 static DEVICE_ATTR(local_time, 0400, etr_local_time_show, NULL);
1333 
1334 static ssize_t etr_utc_offset_show(struct device *dev,
1335 			struct device_attribute *attr, char *buf)
1336 {
1337 	struct etr_aib *aib = etr_aib_from_dev(dev);
1338 
1339 	if (!aib || !aib->slsw.v3)
1340 		return -ENODATA;
1341 	return sprintf(buf, "%i\n", aib->edf3.buo);
1342 }
1343 
1344 static DEVICE_ATTR(utc_offset, 0400, etr_utc_offset_show, NULL);
1345 
1346 static struct device_attribute *etr_port_attributes[] = {
1347 	&dev_attr_online,
1348 	&dev_attr_stepping_control,
1349 	&dev_attr_state_code,
1350 	&dev_attr_untuned,
1351 	&dev_attr_network,
1352 	&dev_attr_id,
1353 	&dev_attr_port,
1354 	&dev_attr_coupled,
1355 	&dev_attr_local_time,
1356 	&dev_attr_utc_offset,
1357 	NULL
1358 };
1359 
1360 static int __init etr_register_port(struct device *dev)
1361 {
1362 	struct device_attribute **attr;
1363 	int rc;
1364 
1365 	rc = device_register(dev);
1366 	if (rc)
1367 		goto out;
1368 	for (attr = etr_port_attributes; *attr; attr++) {
1369 		rc = device_create_file(dev, *attr);
1370 		if (rc)
1371 			goto out_unreg;
1372 	}
1373 	return 0;
1374 out_unreg:
1375 	for (; attr >= etr_port_attributes; attr--)
1376 		device_remove_file(dev, *attr);
1377 	device_unregister(dev);
1378 out:
1379 	return rc;
1380 }
1381 
1382 static void __init etr_unregister_port(struct device *dev)
1383 {
1384 	struct device_attribute **attr;
1385 
1386 	for (attr = etr_port_attributes; *attr; attr++)
1387 		device_remove_file(dev, *attr);
1388 	device_unregister(dev);
1389 }
1390 
1391 static int __init etr_init_sysfs(void)
1392 {
1393 	int rc;
1394 
1395 	rc = subsys_system_register(&etr_subsys, NULL);
1396 	if (rc)
1397 		goto out;
1398 	rc = device_create_file(etr_subsys.dev_root, &dev_attr_stepping_port);
1399 	if (rc)
1400 		goto out_unreg_subsys;
1401 	rc = device_create_file(etr_subsys.dev_root, &dev_attr_stepping_mode);
1402 	if (rc)
1403 		goto out_remove_stepping_port;
1404 	rc = etr_register_port(&etr_port0_dev);
1405 	if (rc)
1406 		goto out_remove_stepping_mode;
1407 	rc = etr_register_port(&etr_port1_dev);
1408 	if (rc)
1409 		goto out_remove_port0;
1410 	return 0;
1411 
1412 out_remove_port0:
1413 	etr_unregister_port(&etr_port0_dev);
1414 out_remove_stepping_mode:
1415 	device_remove_file(etr_subsys.dev_root, &dev_attr_stepping_mode);
1416 out_remove_stepping_port:
1417 	device_remove_file(etr_subsys.dev_root, &dev_attr_stepping_port);
1418 out_unreg_subsys:
1419 	bus_unregister(&etr_subsys);
1420 out:
1421 	return rc;
1422 }
1423 
1424 device_initcall(etr_init_sysfs);
1425 
1426 /*
1427  * Server Time Protocol (STP) code.
1428  */
1429 static int stp_online;
1430 static struct stp_sstpi stp_info;
1431 static void *stp_page;
1432 
1433 static void stp_work_fn(struct work_struct *work);
1434 static DEFINE_MUTEX(stp_work_mutex);
1435 static DECLARE_WORK(stp_work, stp_work_fn);
1436 static struct timer_list stp_timer;
1437 
1438 static int __init early_parse_stp(char *p)
1439 {
1440 	if (strncmp(p, "off", 3) == 0)
1441 		stp_online = 0;
1442 	else if (strncmp(p, "on", 2) == 0)
1443 		stp_online = 1;
1444 	return 0;
1445 }
1446 early_param("stp", early_parse_stp);
1447 
1448 /*
1449  * Reset STP attachment.
1450  */
1451 static void __init stp_reset(void)
1452 {
1453 	int rc;
1454 
1455 	stp_page = (void *) get_zeroed_page(GFP_ATOMIC);
1456 	rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000);
1457 	if (rc == 0)
1458 		set_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags);
1459 	else if (stp_online) {
1460 		pr_warning("The real or virtual hardware system does "
1461 			   "not provide an STP interface\n");
1462 		free_page((unsigned long) stp_page);
1463 		stp_page = NULL;
1464 		stp_online = 0;
1465 	}
1466 }
1467 
1468 static void stp_timeout(unsigned long dummy)
1469 {
1470 	queue_work(time_sync_wq, &stp_work);
1471 }
1472 
1473 static int __init stp_init(void)
1474 {
1475 	if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
1476 		return 0;
1477 	setup_timer(&stp_timer, stp_timeout, 0UL);
1478 	time_init_wq();
1479 	if (!stp_online)
1480 		return 0;
1481 	queue_work(time_sync_wq, &stp_work);
1482 	return 0;
1483 }
1484 
1485 arch_initcall(stp_init);
1486 
1487 /*
1488  * STP timing alert. There are three causes:
1489  * 1) timing status change
1490  * 2) link availability change
1491  * 3) time control parameter change
1492  * In all three cases we are only interested in the clock source state.
1493  * If a STP clock source is now available use it.
1494  */
1495 static void stp_timing_alert(struct stp_irq_parm *intparm)
1496 {
1497 	if (intparm->tsc || intparm->lac || intparm->tcpc)
1498 		queue_work(time_sync_wq, &stp_work);
1499 }
1500 
1501 /*
1502  * STP sync check machine check. This is called when the timing state
1503  * changes from the synchronized state to the unsynchronized state.
1504  * After a STP sync check the clock is not in sync. The machine check
1505  * is broadcasted to all cpus at the same time.
1506  */
1507 void stp_sync_check(void)
1508 {
1509 	disable_sync_clock(NULL);
1510 	queue_work(time_sync_wq, &stp_work);
1511 }
1512 
1513 /*
1514  * STP island condition machine check. This is called when an attached
1515  * server  attempts to communicate over an STP link and the servers
1516  * have matching CTN ids and have a valid stratum-1 configuration
1517  * but the configurations do not match.
1518  */
1519 void stp_island_check(void)
1520 {
1521 	disable_sync_clock(NULL);
1522 	queue_work(time_sync_wq, &stp_work);
1523 }
1524 
1525 
1526 static int stp_sync_clock(void *data)
1527 {
1528 	static int first;
1529 	unsigned long long old_clock, delta, new_clock, clock_delta;
1530 	struct clock_sync_data *stp_sync;
1531 	int rc;
1532 
1533 	stp_sync = data;
1534 
1535 	if (xchg(&first, 1) == 1) {
1536 		/* Slave */
1537 		clock_sync_cpu(stp_sync);
1538 		return 0;
1539 	}
1540 
1541 	/* Wait until all other cpus entered the sync function. */
1542 	while (atomic_read(&stp_sync->cpus) != 0)
1543 		cpu_relax();
1544 
1545 	enable_sync_clock();
1546 
1547 	rc = 0;
1548 	if (stp_info.todoff[0] || stp_info.todoff[1] ||
1549 	    stp_info.todoff[2] || stp_info.todoff[3] ||
1550 	    stp_info.tmd != 2) {
1551 		old_clock = get_tod_clock();
1552 		rc = chsc_sstpc(stp_page, STP_OP_SYNC, 0);
1553 		if (rc == 0) {
1554 			new_clock = get_tod_clock();
1555 			delta = adjust_time(old_clock, new_clock, 0);
1556 			clock_delta = new_clock - old_clock;
1557 			atomic_notifier_call_chain(&s390_epoch_delta_notifier,
1558 						   0, &clock_delta);
1559 			fixup_clock_comparator(delta);
1560 			rc = chsc_sstpi(stp_page, &stp_info,
1561 					sizeof(struct stp_sstpi));
1562 			if (rc == 0 && stp_info.tmd != 2)
1563 				rc = -EAGAIN;
1564 		}
1565 	}
1566 	if (rc) {
1567 		disable_sync_clock(NULL);
1568 		stp_sync->in_sync = -EAGAIN;
1569 	} else
1570 		stp_sync->in_sync = 1;
1571 	xchg(&first, 0);
1572 	return 0;
1573 }
1574 
1575 /*
1576  * STP work. Check for the STP state and take over the clock
1577  * synchronization if the STP clock source is usable.
1578  */
1579 static void stp_work_fn(struct work_struct *work)
1580 {
1581 	struct clock_sync_data stp_sync;
1582 	int rc;
1583 
1584 	/* prevent multiple execution. */
1585 	mutex_lock(&stp_work_mutex);
1586 
1587 	if (!stp_online) {
1588 		chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000);
1589 		del_timer_sync(&stp_timer);
1590 		goto out_unlock;
1591 	}
1592 
1593 	rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xb0e0);
1594 	if (rc)
1595 		goto out_unlock;
1596 
1597 	rc = chsc_sstpi(stp_page, &stp_info, sizeof(struct stp_sstpi));
1598 	if (rc || stp_info.c == 0)
1599 		goto out_unlock;
1600 
1601 	/* Skip synchronization if the clock is already in sync. */
1602 	if (check_sync_clock())
1603 		goto out_unlock;
1604 
1605 	memset(&stp_sync, 0, sizeof(stp_sync));
1606 	get_online_cpus();
1607 	atomic_set(&stp_sync.cpus, num_online_cpus() - 1);
1608 	stop_machine(stp_sync_clock, &stp_sync, cpu_online_mask);
1609 	put_online_cpus();
1610 
1611 	if (!check_sync_clock())
1612 		/*
1613 		 * There is a usable clock but the synchonization failed.
1614 		 * Retry after a second.
1615 		 */
1616 		mod_timer(&stp_timer, jiffies + HZ);
1617 
1618 out_unlock:
1619 	mutex_unlock(&stp_work_mutex);
1620 }
1621 
1622 /*
1623  * STP subsys sysfs interface functions
1624  */
1625 static struct bus_type stp_subsys = {
1626 	.name		= "stp",
1627 	.dev_name	= "stp",
1628 };
1629 
1630 static ssize_t stp_ctn_id_show(struct device *dev,
1631 				struct device_attribute *attr,
1632 				char *buf)
1633 {
1634 	if (!stp_online)
1635 		return -ENODATA;
1636 	return sprintf(buf, "%016llx\n",
1637 		       *(unsigned long long *) stp_info.ctnid);
1638 }
1639 
1640 static DEVICE_ATTR(ctn_id, 0400, stp_ctn_id_show, NULL);
1641 
1642 static ssize_t stp_ctn_type_show(struct device *dev,
1643 				struct device_attribute *attr,
1644 				char *buf)
1645 {
1646 	if (!stp_online)
1647 		return -ENODATA;
1648 	return sprintf(buf, "%i\n", stp_info.ctn);
1649 }
1650 
1651 static DEVICE_ATTR(ctn_type, 0400, stp_ctn_type_show, NULL);
1652 
1653 static ssize_t stp_dst_offset_show(struct device *dev,
1654 				   struct device_attribute *attr,
1655 				   char *buf)
1656 {
1657 	if (!stp_online || !(stp_info.vbits & 0x2000))
1658 		return -ENODATA;
1659 	return sprintf(buf, "%i\n", (int)(s16) stp_info.dsto);
1660 }
1661 
1662 static DEVICE_ATTR(dst_offset, 0400, stp_dst_offset_show, NULL);
1663 
1664 static ssize_t stp_leap_seconds_show(struct device *dev,
1665 					struct device_attribute *attr,
1666 					char *buf)
1667 {
1668 	if (!stp_online || !(stp_info.vbits & 0x8000))
1669 		return -ENODATA;
1670 	return sprintf(buf, "%i\n", (int)(s16) stp_info.leaps);
1671 }
1672 
1673 static DEVICE_ATTR(leap_seconds, 0400, stp_leap_seconds_show, NULL);
1674 
1675 static ssize_t stp_stratum_show(struct device *dev,
1676 				struct device_attribute *attr,
1677 				char *buf)
1678 {
1679 	if (!stp_online)
1680 		return -ENODATA;
1681 	return sprintf(buf, "%i\n", (int)(s16) stp_info.stratum);
1682 }
1683 
1684 static DEVICE_ATTR(stratum, 0400, stp_stratum_show, NULL);
1685 
1686 static ssize_t stp_time_offset_show(struct device *dev,
1687 				struct device_attribute *attr,
1688 				char *buf)
1689 {
1690 	if (!stp_online || !(stp_info.vbits & 0x0800))
1691 		return -ENODATA;
1692 	return sprintf(buf, "%i\n", (int) stp_info.tto);
1693 }
1694 
1695 static DEVICE_ATTR(time_offset, 0400, stp_time_offset_show, NULL);
1696 
1697 static ssize_t stp_time_zone_offset_show(struct device *dev,
1698 				struct device_attribute *attr,
1699 				char *buf)
1700 {
1701 	if (!stp_online || !(stp_info.vbits & 0x4000))
1702 		return -ENODATA;
1703 	return sprintf(buf, "%i\n", (int)(s16) stp_info.tzo);
1704 }
1705 
1706 static DEVICE_ATTR(time_zone_offset, 0400,
1707 			 stp_time_zone_offset_show, NULL);
1708 
1709 static ssize_t stp_timing_mode_show(struct device *dev,
1710 				struct device_attribute *attr,
1711 				char *buf)
1712 {
1713 	if (!stp_online)
1714 		return -ENODATA;
1715 	return sprintf(buf, "%i\n", stp_info.tmd);
1716 }
1717 
1718 static DEVICE_ATTR(timing_mode, 0400, stp_timing_mode_show, NULL);
1719 
1720 static ssize_t stp_timing_state_show(struct device *dev,
1721 				struct device_attribute *attr,
1722 				char *buf)
1723 {
1724 	if (!stp_online)
1725 		return -ENODATA;
1726 	return sprintf(buf, "%i\n", stp_info.tst);
1727 }
1728 
1729 static DEVICE_ATTR(timing_state, 0400, stp_timing_state_show, NULL);
1730 
1731 static ssize_t stp_online_show(struct device *dev,
1732 				struct device_attribute *attr,
1733 				char *buf)
1734 {
1735 	return sprintf(buf, "%i\n", stp_online);
1736 }
1737 
1738 static ssize_t stp_online_store(struct device *dev,
1739 				struct device_attribute *attr,
1740 				const char *buf, size_t count)
1741 {
1742 	unsigned int value;
1743 
1744 	value = simple_strtoul(buf, NULL, 0);
1745 	if (value != 0 && value != 1)
1746 		return -EINVAL;
1747 	if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
1748 		return -EOPNOTSUPP;
1749 	mutex_lock(&clock_sync_mutex);
1750 	stp_online = value;
1751 	if (stp_online)
1752 		set_bit(CLOCK_SYNC_STP, &clock_sync_flags);
1753 	else
1754 		clear_bit(CLOCK_SYNC_STP, &clock_sync_flags);
1755 	queue_work(time_sync_wq, &stp_work);
1756 	mutex_unlock(&clock_sync_mutex);
1757 	return count;
1758 }
1759 
1760 /*
1761  * Can't use DEVICE_ATTR because the attribute should be named
1762  * stp/online but dev_attr_online already exists in this file ..
1763  */
1764 static struct device_attribute dev_attr_stp_online = {
1765 	.attr = { .name = "online", .mode = 0600 },
1766 	.show	= stp_online_show,
1767 	.store	= stp_online_store,
1768 };
1769 
1770 static struct device_attribute *stp_attributes[] = {
1771 	&dev_attr_ctn_id,
1772 	&dev_attr_ctn_type,
1773 	&dev_attr_dst_offset,
1774 	&dev_attr_leap_seconds,
1775 	&dev_attr_stp_online,
1776 	&dev_attr_stratum,
1777 	&dev_attr_time_offset,
1778 	&dev_attr_time_zone_offset,
1779 	&dev_attr_timing_mode,
1780 	&dev_attr_timing_state,
1781 	NULL
1782 };
1783 
1784 static int __init stp_init_sysfs(void)
1785 {
1786 	struct device_attribute **attr;
1787 	int rc;
1788 
1789 	rc = subsys_system_register(&stp_subsys, NULL);
1790 	if (rc)
1791 		goto out;
1792 	for (attr = stp_attributes; *attr; attr++) {
1793 		rc = device_create_file(stp_subsys.dev_root, *attr);
1794 		if (rc)
1795 			goto out_unreg;
1796 	}
1797 	return 0;
1798 out_unreg:
1799 	for (; attr >= stp_attributes; attr--)
1800 		device_remove_file(stp_subsys.dev_root, *attr);
1801 	bus_unregister(&stp_subsys);
1802 out:
1803 	return rc;
1804 }
1805 
1806 device_initcall(stp_init_sysfs);
1807