Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * This file contains functions which manage clock event devices.
4 *
5 * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
6 * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
7 * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
8 */
9
10#include <linux/clockchips.h>
11#include <linux/hrtimer.h>
12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/smp.h>
15#include <linux/device.h>
16
17#include "tick-internal.h"
18
19/* The registered clock event devices */
20static LIST_HEAD(clockevent_devices);
21static LIST_HEAD(clockevents_released);
22/* Protection for the above */
23static DEFINE_RAW_SPINLOCK(clockevents_lock);
24/* Protection for unbind operations */
25static DEFINE_MUTEX(clockevents_mutex);
26
27struct ce_unbind {
28 struct clock_event_device *ce;
29 int res;
30};
31
32static u64 cev_delta2ns(unsigned long latch, struct clock_event_device *evt,
33 bool ismax)
34{
35 u64 clc = (u64) latch << evt->shift;
36 u64 rnd;
37
38 if (WARN_ON(!evt->mult))
39 evt->mult = 1;
40 rnd = (u64) evt->mult - 1;
41
42 /*
43 * Upper bound sanity check. If the backwards conversion is
44 * not equal latch, we know that the above shift overflowed.
45 */
46 if ((clc >> evt->shift) != (u64)latch)
47 clc = ~0ULL;
48
49 /*
50 * Scaled math oddities:
51 *
52 * For mult <= (1 << shift) we can safely add mult - 1 to
53 * prevent integer rounding loss. So the backwards conversion
54 * from nsec to device ticks will be correct.
55 *
56 * For mult > (1 << shift), i.e. device frequency is > 1GHz we
57 * need to be careful. Adding mult - 1 will result in a value
58 * which when converted back to device ticks can be larger
59 * than latch by up to (mult - 1) >> shift. For the min_delta
60 * calculation we still want to apply this in order to stay
61 * above the minimum device ticks limit. For the upper limit
62 * we would end up with a latch value larger than the upper
63 * limit of the device, so we omit the add to stay below the
64 * device upper boundary.
65 *
66 * Also omit the add if it would overflow the u64 boundary.
67 */
68 if ((~0ULL - clc > rnd) &&
69 (!ismax || evt->mult <= (1ULL << evt->shift)))
70 clc += rnd;
71
72 do_div(clc, evt->mult);
73
74 /* Deltas less than 1usec are pointless noise */
75 return clc > 1000 ? clc : 1000;
76}
77
78/**
79 * clockevents_delta2ns - Convert a latch value (device ticks) to nanoseconds
80 * @latch: value to convert
81 * @evt: pointer to clock event device descriptor
82 *
83 * Math helper, returns latch value converted to nanoseconds (bound checked)
84 */
85u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt)
86{
87 return cev_delta2ns(latch, evt, false);
88}
89EXPORT_SYMBOL_GPL(clockevent_delta2ns);
90
91static int __clockevents_switch_state(struct clock_event_device *dev,
92 enum clock_event_state state)
93{
94 if (dev->features & CLOCK_EVT_FEAT_DUMMY)
95 return 0;
96
97 /* Transition with new state-specific callbacks */
98 switch (state) {
99 case CLOCK_EVT_STATE_DETACHED:
100 /* The clockevent device is getting replaced. Shut it down. */
101
102 case CLOCK_EVT_STATE_SHUTDOWN:
103 if (dev->set_state_shutdown)
104 return dev->set_state_shutdown(dev);
105 return 0;
106
107 case CLOCK_EVT_STATE_PERIODIC:
108 /* Core internal bug */
109 if (!(dev->features & CLOCK_EVT_FEAT_PERIODIC))
110 return -ENOSYS;
111 if (dev->set_state_periodic)
112 return dev->set_state_periodic(dev);
113 return 0;
114
115 case CLOCK_EVT_STATE_ONESHOT:
116 /* Core internal bug */
117 if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
118 return -ENOSYS;
119 if (dev->set_state_oneshot)
120 return dev->set_state_oneshot(dev);
121 return 0;
122
123 case CLOCK_EVT_STATE_ONESHOT_STOPPED:
124 /* Core internal bug */
125 if (WARN_ONCE(!clockevent_state_oneshot(dev),
126 "Current state: %d\n",
127 clockevent_get_state(dev)))
128 return -EINVAL;
129
130 if (dev->set_state_oneshot_stopped)
131 return dev->set_state_oneshot_stopped(dev);
132 else
133 return -ENOSYS;
134
135 default:
136 return -ENOSYS;
137 }
138}
139
140/**
141 * clockevents_switch_state - set the operating state of a clock event device
142 * @dev: device to modify
143 * @state: new state
144 *
145 * Must be called with interrupts disabled !
146 */
147void clockevents_switch_state(struct clock_event_device *dev,
148 enum clock_event_state state)
149{
150 if (clockevent_get_state(dev) != state) {
151 if (__clockevents_switch_state(dev, state))
152 return;
153
154 clockevent_set_state(dev, state);
155
156 /*
157 * A nsec2cyc multiplicator of 0 is invalid and we'd crash
158 * on it, so fix it up and emit a warning:
159 */
160 if (clockevent_state_oneshot(dev)) {
161 if (WARN_ON(!dev->mult))
162 dev->mult = 1;
163 }
164 }
165}
166
167/**
168 * clockevents_shutdown - shutdown the device and clear next_event
169 * @dev: device to shutdown
170 */
171void clockevents_shutdown(struct clock_event_device *dev)
172{
173 clockevents_switch_state(dev, CLOCK_EVT_STATE_SHUTDOWN);
174 dev->next_event = KTIME_MAX;
175}
176
177/**
178 * clockevents_tick_resume - Resume the tick device before using it again
179 * @dev: device to resume
180 */
181int clockevents_tick_resume(struct clock_event_device *dev)
182{
183 int ret = 0;
184
185 if (dev->tick_resume)
186 ret = dev->tick_resume(dev);
187
188 return ret;
189}
190
191#ifdef CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST
192
193/* Limit min_delta to a jiffie */
194#define MIN_DELTA_LIMIT (NSEC_PER_SEC / HZ)
195
196/**
197 * clockevents_increase_min_delta - raise minimum delta of a clock event device
198 * @dev: device to increase the minimum delta
199 *
200 * Returns 0 on success, -ETIME when the minimum delta reached the limit.
201 */
202static int clockevents_increase_min_delta(struct clock_event_device *dev)
203{
204 /* Nothing to do if we already reached the limit */
205 if (dev->min_delta_ns >= MIN_DELTA_LIMIT) {
206 printk_deferred(KERN_WARNING
207 "CE: Reprogramming failure. Giving up\n");
208 dev->next_event = KTIME_MAX;
209 return -ETIME;
210 }
211
212 if (dev->min_delta_ns < 5000)
213 dev->min_delta_ns = 5000;
214 else
215 dev->min_delta_ns += dev->min_delta_ns >> 1;
216
217 if (dev->min_delta_ns > MIN_DELTA_LIMIT)
218 dev->min_delta_ns = MIN_DELTA_LIMIT;
219
220 printk_deferred(KERN_WARNING
221 "CE: %s increased min_delta_ns to %llu nsec\n",
222 dev->name ? dev->name : "?",
223 (unsigned long long) dev->min_delta_ns);
224 return 0;
225}
226
227/**
228 * clockevents_program_min_delta - Set clock event device to the minimum delay.
229 * @dev: device to program
230 *
231 * Returns 0 on success, -ETIME when the retry loop failed.
232 */
233static int clockevents_program_min_delta(struct clock_event_device *dev)
234{
235 unsigned long long clc;
236 int64_t delta;
237 int i;
238
239 for (i = 0;;) {
240 delta = dev->min_delta_ns;
241 dev->next_event = ktime_add_ns(ktime_get(), delta);
242
243 if (clockevent_state_shutdown(dev))
244 return 0;
245
246 dev->retries++;
247 clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
248 if (dev->set_next_event((unsigned long) clc, dev) == 0)
249 return 0;
250
251 if (++i > 2) {
252 /*
253 * We tried 3 times to program the device with the
254 * given min_delta_ns. Try to increase the minimum
255 * delta, if that fails as well get out of here.
256 */
257 if (clockevents_increase_min_delta(dev))
258 return -ETIME;
259 i = 0;
260 }
261 }
262}
263
264#else /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */
265
266/**
267 * clockevents_program_min_delta - Set clock event device to the minimum delay.
268 * @dev: device to program
269 *
270 * Returns 0 on success, -ETIME when the retry loop failed.
271 */
272static int clockevents_program_min_delta(struct clock_event_device *dev)
273{
274 unsigned long long clc;
275 int64_t delta = 0;
276 int i;
277
278 for (i = 0; i < 10; i++) {
279 delta += dev->min_delta_ns;
280 dev->next_event = ktime_add_ns(ktime_get(), delta);
281
282 if (clockevent_state_shutdown(dev))
283 return 0;
284
285 dev->retries++;
286 clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
287 if (dev->set_next_event((unsigned long) clc, dev) == 0)
288 return 0;
289 }
290 return -ETIME;
291}
292
293#endif /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */
294
295/**
296 * clockevents_program_event - Reprogram the clock event device.
297 * @dev: device to program
298 * @expires: absolute expiry time (monotonic clock)
299 * @force: program minimum delay if expires can not be set
300 *
301 * Returns 0 on success, -ETIME when the event is in the past.
302 */
303int clockevents_program_event(struct clock_event_device *dev, ktime_t expires,
304 bool force)
305{
306 unsigned long long clc;
307 int64_t delta;
308 int rc;
309
310 if (WARN_ON_ONCE(expires < 0))
311 return -ETIME;
312
313 dev->next_event = expires;
314
315 if (clockevent_state_shutdown(dev))
316 return 0;
317
318 /* We must be in ONESHOT state here */
319 WARN_ONCE(!clockevent_state_oneshot(dev), "Current state: %d\n",
320 clockevent_get_state(dev));
321
322 /* Shortcut for clockevent devices that can deal with ktime. */
323 if (dev->features & CLOCK_EVT_FEAT_KTIME)
324 return dev->set_next_ktime(expires, dev);
325
326 delta = ktime_to_ns(ktime_sub(expires, ktime_get()));
327 if (delta <= 0)
328 return force ? clockevents_program_min_delta(dev) : -ETIME;
329
330 delta = min(delta, (int64_t) dev->max_delta_ns);
331 delta = max(delta, (int64_t) dev->min_delta_ns);
332
333 clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
334 rc = dev->set_next_event((unsigned long) clc, dev);
335
336 return (rc && force) ? clockevents_program_min_delta(dev) : rc;
337}
338
339/*
340 * Called after a notify add to make devices available which were
341 * released from the notifier call.
342 */
343static void clockevents_notify_released(void)
344{
345 struct clock_event_device *dev;
346
347 while (!list_empty(&clockevents_released)) {
348 dev = list_entry(clockevents_released.next,
349 struct clock_event_device, list);
350 list_del(&dev->list);
351 list_add(&dev->list, &clockevent_devices);
352 tick_check_new_device(dev);
353 }
354}
355
356/*
357 * Try to install a replacement clock event device
358 */
359static int clockevents_replace(struct clock_event_device *ced)
360{
361 struct clock_event_device *dev, *newdev = NULL;
362
363 list_for_each_entry(dev, &clockevent_devices, list) {
364 if (dev == ced || !clockevent_state_detached(dev))
365 continue;
366
367 if (!tick_check_replacement(newdev, dev))
368 continue;
369
370 if (!try_module_get(dev->owner))
371 continue;
372
373 if (newdev)
374 module_put(newdev->owner);
375 newdev = dev;
376 }
377 if (newdev) {
378 tick_install_replacement(newdev);
379 list_del_init(&ced->list);
380 }
381 return newdev ? 0 : -EBUSY;
382}
383
384/*
385 * Called with clockevents_mutex and clockevents_lock held
386 */
387static int __clockevents_try_unbind(struct clock_event_device *ced, int cpu)
388{
389 /* Fast track. Device is unused */
390 if (clockevent_state_detached(ced)) {
391 list_del_init(&ced->list);
392 return 0;
393 }
394
395 return ced == per_cpu(tick_cpu_device, cpu).evtdev ? -EAGAIN : -EBUSY;
396}
397
398/*
399 * SMP function call to unbind a device
400 */
401static void __clockevents_unbind(void *arg)
402{
403 struct ce_unbind *cu = arg;
404 int res;
405
406 raw_spin_lock(&clockevents_lock);
407 res = __clockevents_try_unbind(cu->ce, smp_processor_id());
408 if (res == -EAGAIN)
409 res = clockevents_replace(cu->ce);
410 cu->res = res;
411 raw_spin_unlock(&clockevents_lock);
412}
413
414/*
415 * Issues smp function call to unbind a per cpu device. Called with
416 * clockevents_mutex held.
417 */
418static int clockevents_unbind(struct clock_event_device *ced, int cpu)
419{
420 struct ce_unbind cu = { .ce = ced, .res = -ENODEV };
421
422 smp_call_function_single(cpu, __clockevents_unbind, &cu, 1);
423 return cu.res;
424}
425
426/*
427 * Unbind a clockevents device.
428 */
429int clockevents_unbind_device(struct clock_event_device *ced, int cpu)
430{
431 int ret;
432
433 mutex_lock(&clockevents_mutex);
434 ret = clockevents_unbind(ced, cpu);
435 mutex_unlock(&clockevents_mutex);
436 return ret;
437}
438EXPORT_SYMBOL_GPL(clockevents_unbind_device);
439
440/**
441 * clockevents_register_device - register a clock event device
442 * @dev: device to register
443 */
444void clockevents_register_device(struct clock_event_device *dev)
445{
446 unsigned long flags;
447
448 /* Initialize state to DETACHED */
449 clockevent_set_state(dev, CLOCK_EVT_STATE_DETACHED);
450
451 if (!dev->cpumask) {
452 WARN_ON(num_possible_cpus() > 1);
453 dev->cpumask = cpumask_of(smp_processor_id());
454 }
455
456 if (dev->cpumask == cpu_all_mask) {
457 WARN(1, "%s cpumask == cpu_all_mask, using cpu_possible_mask instead\n",
458 dev->name);
459 dev->cpumask = cpu_possible_mask;
460 }
461
462 raw_spin_lock_irqsave(&clockevents_lock, flags);
463
464 list_add(&dev->list, &clockevent_devices);
465 tick_check_new_device(dev);
466 clockevents_notify_released();
467
468 raw_spin_unlock_irqrestore(&clockevents_lock, flags);
469}
470EXPORT_SYMBOL_GPL(clockevents_register_device);
471
472static void clockevents_config(struct clock_event_device *dev, u32 freq)
473{
474 u64 sec;
475
476 if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
477 return;
478
479 /*
480 * Calculate the maximum number of seconds we can sleep. Limit
481 * to 10 minutes for hardware which can program more than
482 * 32bit ticks so we still get reasonable conversion values.
483 */
484 sec = dev->max_delta_ticks;
485 do_div(sec, freq);
486 if (!sec)
487 sec = 1;
488 else if (sec > 600 && dev->max_delta_ticks > UINT_MAX)
489 sec = 600;
490
491 clockevents_calc_mult_shift(dev, freq, sec);
492 dev->min_delta_ns = cev_delta2ns(dev->min_delta_ticks, dev, false);
493 dev->max_delta_ns = cev_delta2ns(dev->max_delta_ticks, dev, true);
494}
495
496/**
497 * clockevents_config_and_register - Configure and register a clock event device
498 * @dev: device to register
499 * @freq: The clock frequency
500 * @min_delta: The minimum clock ticks to program in oneshot mode
501 * @max_delta: The maximum clock ticks to program in oneshot mode
502 *
503 * min/max_delta can be 0 for devices which do not support oneshot mode.
504 */
505void clockevents_config_and_register(struct clock_event_device *dev,
506 u32 freq, unsigned long min_delta,
507 unsigned long max_delta)
508{
509 dev->min_delta_ticks = min_delta;
510 dev->max_delta_ticks = max_delta;
511 clockevents_config(dev, freq);
512 clockevents_register_device(dev);
513}
514EXPORT_SYMBOL_GPL(clockevents_config_and_register);
515
516int __clockevents_update_freq(struct clock_event_device *dev, u32 freq)
517{
518 clockevents_config(dev, freq);
519
520 if (clockevent_state_oneshot(dev))
521 return clockevents_program_event(dev, dev->next_event, false);
522
523 if (clockevent_state_periodic(dev))
524 return __clockevents_switch_state(dev, CLOCK_EVT_STATE_PERIODIC);
525
526 return 0;
527}
528
529/**
530 * clockevents_update_freq - Update frequency and reprogram a clock event device.
531 * @dev: device to modify
532 * @freq: new device frequency
533 *
534 * Reconfigure and reprogram a clock event device in oneshot
535 * mode. Must be called on the cpu for which the device delivers per
536 * cpu timer events. If called for the broadcast device the core takes
537 * care of serialization.
538 *
539 * Returns 0 on success, -ETIME when the event is in the past.
540 */
541int clockevents_update_freq(struct clock_event_device *dev, u32 freq)
542{
543 unsigned long flags;
544 int ret;
545
546 local_irq_save(flags);
547 ret = tick_broadcast_update_freq(dev, freq);
548 if (ret == -ENODEV)
549 ret = __clockevents_update_freq(dev, freq);
550 local_irq_restore(flags);
551 return ret;
552}
553
554/*
555 * Noop handler when we shut down an event device
556 */
557void clockevents_handle_noop(struct clock_event_device *dev)
558{
559}
560
561/**
562 * clockevents_exchange_device - release and request clock devices
563 * @old: device to release (can be NULL)
564 * @new: device to request (can be NULL)
565 *
566 * Called from various tick functions with clockevents_lock held and
567 * interrupts disabled.
568 */
569void clockevents_exchange_device(struct clock_event_device *old,
570 struct clock_event_device *new)
571{
572 /*
573 * Caller releases a clock event device. We queue it into the
574 * released list and do a notify add later.
575 */
576 if (old) {
577 module_put(old->owner);
578 clockevents_switch_state(old, CLOCK_EVT_STATE_DETACHED);
579 list_del(&old->list);
580 list_add(&old->list, &clockevents_released);
581 }
582
583 if (new) {
584 BUG_ON(!clockevent_state_detached(new));
585 clockevents_shutdown(new);
586 }
587}
588
589/**
590 * clockevents_suspend - suspend clock devices
591 */
592void clockevents_suspend(void)
593{
594 struct clock_event_device *dev;
595
596 list_for_each_entry_reverse(dev, &clockevent_devices, list)
597 if (dev->suspend && !clockevent_state_detached(dev))
598 dev->suspend(dev);
599}
600
601/**
602 * clockevents_resume - resume clock devices
603 */
604void clockevents_resume(void)
605{
606 struct clock_event_device *dev;
607
608 list_for_each_entry(dev, &clockevent_devices, list)
609 if (dev->resume && !clockevent_state_detached(dev))
610 dev->resume(dev);
611}
612
613#ifdef CONFIG_HOTPLUG_CPU
614
615# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
616/**
617 * tick_offline_cpu - Take CPU out of the broadcast mechanism
618 * @cpu: The outgoing CPU
619 *
620 * Called on the outgoing CPU after it took itself offline.
621 */
622void tick_offline_cpu(unsigned int cpu)
623{
624 raw_spin_lock(&clockevents_lock);
625 tick_broadcast_offline(cpu);
626 raw_spin_unlock(&clockevents_lock);
627}
628# endif
629
630/**
631 * tick_cleanup_dead_cpu - Cleanup the tick and clockevents of a dead cpu
632 */
633void tick_cleanup_dead_cpu(int cpu)
634{
635 struct clock_event_device *dev, *tmp;
636 unsigned long flags;
637
638 raw_spin_lock_irqsave(&clockevents_lock, flags);
639
640 tick_shutdown(cpu);
641 /*
642 * Unregister the clock event devices which were
643 * released from the users in the notify chain.
644 */
645 list_for_each_entry_safe(dev, tmp, &clockevents_released, list)
646 list_del(&dev->list);
647 /*
648 * Now check whether the CPU has left unused per cpu devices
649 */
650 list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) {
651 if (cpumask_test_cpu(cpu, dev->cpumask) &&
652 cpumask_weight(dev->cpumask) == 1 &&
653 !tick_is_broadcast_device(dev)) {
654 BUG_ON(!clockevent_state_detached(dev));
655 list_del(&dev->list);
656 }
657 }
658 raw_spin_unlock_irqrestore(&clockevents_lock, flags);
659}
660#endif
661
662#ifdef CONFIG_SYSFS
663static struct bus_type clockevents_subsys = {
664 .name = "clockevents",
665 .dev_name = "clockevent",
666};
667
668static DEFINE_PER_CPU(struct device, tick_percpu_dev);
669static struct tick_device *tick_get_tick_dev(struct device *dev);
670
671static ssize_t sysfs_show_current_tick_dev(struct device *dev,
672 struct device_attribute *attr,
673 char *buf)
674{
675 struct tick_device *td;
676 ssize_t count = 0;
677
678 raw_spin_lock_irq(&clockevents_lock);
679 td = tick_get_tick_dev(dev);
680 if (td && td->evtdev)
681 count = snprintf(buf, PAGE_SIZE, "%s\n", td->evtdev->name);
682 raw_spin_unlock_irq(&clockevents_lock);
683 return count;
684}
685static DEVICE_ATTR(current_device, 0444, sysfs_show_current_tick_dev, NULL);
686
687/* We don't support the abomination of removable broadcast devices */
688static ssize_t sysfs_unbind_tick_dev(struct device *dev,
689 struct device_attribute *attr,
690 const char *buf, size_t count)
691{
692 char name[CS_NAME_LEN];
693 ssize_t ret = sysfs_get_uname(buf, name, count);
694 struct clock_event_device *ce;
695
696 if (ret < 0)
697 return ret;
698
699 ret = -ENODEV;
700 mutex_lock(&clockevents_mutex);
701 raw_spin_lock_irq(&clockevents_lock);
702 list_for_each_entry(ce, &clockevent_devices, list) {
703 if (!strcmp(ce->name, name)) {
704 ret = __clockevents_try_unbind(ce, dev->id);
705 break;
706 }
707 }
708 raw_spin_unlock_irq(&clockevents_lock);
709 /*
710 * We hold clockevents_mutex, so ce can't go away
711 */
712 if (ret == -EAGAIN)
713 ret = clockevents_unbind(ce, dev->id);
714 mutex_unlock(&clockevents_mutex);
715 return ret ? ret : count;
716}
717static DEVICE_ATTR(unbind_device, 0200, NULL, sysfs_unbind_tick_dev);
718
719#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
720static struct device tick_bc_dev = {
721 .init_name = "broadcast",
722 .id = 0,
723 .bus = &clockevents_subsys,
724};
725
726static struct tick_device *tick_get_tick_dev(struct device *dev)
727{
728 return dev == &tick_bc_dev ? tick_get_broadcast_device() :
729 &per_cpu(tick_cpu_device, dev->id);
730}
731
732static __init int tick_broadcast_init_sysfs(void)
733{
734 int err = device_register(&tick_bc_dev);
735
736 if (!err)
737 err = device_create_file(&tick_bc_dev, &dev_attr_current_device);
738 return err;
739}
740#else
741static struct tick_device *tick_get_tick_dev(struct device *dev)
742{
743 return &per_cpu(tick_cpu_device, dev->id);
744}
745static inline int tick_broadcast_init_sysfs(void) { return 0; }
746#endif
747
748static int __init tick_init_sysfs(void)
749{
750 int cpu;
751
752 for_each_possible_cpu(cpu) {
753 struct device *dev = &per_cpu(tick_percpu_dev, cpu);
754 int err;
755
756 dev->id = cpu;
757 dev->bus = &clockevents_subsys;
758 err = device_register(dev);
759 if (!err)
760 err = device_create_file(dev, &dev_attr_current_device);
761 if (!err)
762 err = device_create_file(dev, &dev_attr_unbind_device);
763 if (err)
764 return err;
765 }
766 return tick_broadcast_init_sysfs();
767}
768
769static int __init clockevents_init_sysfs(void)
770{
771 int err = subsys_system_register(&clockevents_subsys, NULL);
772
773 if (!err)
774 err = tick_init_sysfs();
775 return err;
776}
777device_initcall(clockevents_init_sysfs);
778#endif /* SYSFS */
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * This file contains functions which manage clock event devices.
4 *
5 * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
6 * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
7 * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
8 */
9
10#include <linux/clockchips.h>
11#include <linux/hrtimer.h>
12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/smp.h>
15#include <linux/device.h>
16
17#include "tick-internal.h"
18
19/* The registered clock event devices */
20static LIST_HEAD(clockevent_devices);
21static LIST_HEAD(clockevents_released);
22/* Protection for the above */
23static DEFINE_RAW_SPINLOCK(clockevents_lock);
24/* Protection for unbind operations */
25static DEFINE_MUTEX(clockevents_mutex);
26
27struct ce_unbind {
28 struct clock_event_device *ce;
29 int res;
30};
31
32static u64 cev_delta2ns(unsigned long latch, struct clock_event_device *evt,
33 bool ismax)
34{
35 u64 clc = (u64) latch << evt->shift;
36 u64 rnd;
37
38 if (WARN_ON(!evt->mult))
39 evt->mult = 1;
40 rnd = (u64) evt->mult - 1;
41
42 /*
43 * Upper bound sanity check. If the backwards conversion is
44 * not equal latch, we know that the above shift overflowed.
45 */
46 if ((clc >> evt->shift) != (u64)latch)
47 clc = ~0ULL;
48
49 /*
50 * Scaled math oddities:
51 *
52 * For mult <= (1 << shift) we can safely add mult - 1 to
53 * prevent integer rounding loss. So the backwards conversion
54 * from nsec to device ticks will be correct.
55 *
56 * For mult > (1 << shift), i.e. device frequency is > 1GHz we
57 * need to be careful. Adding mult - 1 will result in a value
58 * which when converted back to device ticks can be larger
59 * than latch by up to (mult - 1) >> shift. For the min_delta
60 * calculation we still want to apply this in order to stay
61 * above the minimum device ticks limit. For the upper limit
62 * we would end up with a latch value larger than the upper
63 * limit of the device, so we omit the add to stay below the
64 * device upper boundary.
65 *
66 * Also omit the add if it would overflow the u64 boundary.
67 */
68 if ((~0ULL - clc > rnd) &&
69 (!ismax || evt->mult <= (1ULL << evt->shift)))
70 clc += rnd;
71
72 do_div(clc, evt->mult);
73
74 /* Deltas less than 1usec are pointless noise */
75 return clc > 1000 ? clc : 1000;
76}
77
78/**
79 * clockevent_delta2ns - Convert a latch value (device ticks) to nanoseconds
80 * @latch: value to convert
81 * @evt: pointer to clock event device descriptor
82 *
83 * Math helper, returns latch value converted to nanoseconds (bound checked)
84 */
85u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt)
86{
87 return cev_delta2ns(latch, evt, false);
88}
89EXPORT_SYMBOL_GPL(clockevent_delta2ns);
90
91static int __clockevents_switch_state(struct clock_event_device *dev,
92 enum clock_event_state state)
93{
94 if (dev->features & CLOCK_EVT_FEAT_DUMMY)
95 return 0;
96
97 /* Transition with new state-specific callbacks */
98 switch (state) {
99 case CLOCK_EVT_STATE_DETACHED:
100 /* The clockevent device is getting replaced. Shut it down. */
101
102 case CLOCK_EVT_STATE_SHUTDOWN:
103 if (dev->set_state_shutdown)
104 return dev->set_state_shutdown(dev);
105 return 0;
106
107 case CLOCK_EVT_STATE_PERIODIC:
108 /* Core internal bug */
109 if (!(dev->features & CLOCK_EVT_FEAT_PERIODIC))
110 return -ENOSYS;
111 if (dev->set_state_periodic)
112 return dev->set_state_periodic(dev);
113 return 0;
114
115 case CLOCK_EVT_STATE_ONESHOT:
116 /* Core internal bug */
117 if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
118 return -ENOSYS;
119 if (dev->set_state_oneshot)
120 return dev->set_state_oneshot(dev);
121 return 0;
122
123 case CLOCK_EVT_STATE_ONESHOT_STOPPED:
124 /* Core internal bug */
125 if (WARN_ONCE(!clockevent_state_oneshot(dev),
126 "Current state: %d\n",
127 clockevent_get_state(dev)))
128 return -EINVAL;
129
130 if (dev->set_state_oneshot_stopped)
131 return dev->set_state_oneshot_stopped(dev);
132 else
133 return -ENOSYS;
134
135 default:
136 return -ENOSYS;
137 }
138}
139
140/**
141 * clockevents_switch_state - set the operating state of a clock event device
142 * @dev: device to modify
143 * @state: new state
144 *
145 * Must be called with interrupts disabled !
146 */
147void clockevents_switch_state(struct clock_event_device *dev,
148 enum clock_event_state state)
149{
150 if (clockevent_get_state(dev) != state) {
151 if (__clockevents_switch_state(dev, state))
152 return;
153
154 clockevent_set_state(dev, state);
155
156 /*
157 * A nsec2cyc multiplicator of 0 is invalid and we'd crash
158 * on it, so fix it up and emit a warning:
159 */
160 if (clockevent_state_oneshot(dev)) {
161 if (WARN_ON(!dev->mult))
162 dev->mult = 1;
163 }
164 }
165}
166
167/**
168 * clockevents_shutdown - shutdown the device and clear next_event
169 * @dev: device to shutdown
170 */
171void clockevents_shutdown(struct clock_event_device *dev)
172{
173 clockevents_switch_state(dev, CLOCK_EVT_STATE_SHUTDOWN);
174 dev->next_event = KTIME_MAX;
175}
176
177/**
178 * clockevents_tick_resume - Resume the tick device before using it again
179 * @dev: device to resume
180 */
181int clockevents_tick_resume(struct clock_event_device *dev)
182{
183 int ret = 0;
184
185 if (dev->tick_resume)
186 ret = dev->tick_resume(dev);
187
188 return ret;
189}
190
191#ifdef CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST
192
193/* Limit min_delta to a jiffie */
194#define MIN_DELTA_LIMIT (NSEC_PER_SEC / HZ)
195
196/**
197 * clockevents_increase_min_delta - raise minimum delta of a clock event device
198 * @dev: device to increase the minimum delta
199 *
200 * Returns 0 on success, -ETIME when the minimum delta reached the limit.
201 */
202static int clockevents_increase_min_delta(struct clock_event_device *dev)
203{
204 /* Nothing to do if we already reached the limit */
205 if (dev->min_delta_ns >= MIN_DELTA_LIMIT) {
206 printk_deferred(KERN_WARNING
207 "CE: Reprogramming failure. Giving up\n");
208 dev->next_event = KTIME_MAX;
209 return -ETIME;
210 }
211
212 if (dev->min_delta_ns < 5000)
213 dev->min_delta_ns = 5000;
214 else
215 dev->min_delta_ns += dev->min_delta_ns >> 1;
216
217 if (dev->min_delta_ns > MIN_DELTA_LIMIT)
218 dev->min_delta_ns = MIN_DELTA_LIMIT;
219
220 printk_deferred(KERN_WARNING
221 "CE: %s increased min_delta_ns to %llu nsec\n",
222 dev->name ? dev->name : "?",
223 (unsigned long long) dev->min_delta_ns);
224 return 0;
225}
226
227/**
228 * clockevents_program_min_delta - Set clock event device to the minimum delay.
229 * @dev: device to program
230 *
231 * Returns 0 on success, -ETIME when the retry loop failed.
232 */
233static int clockevents_program_min_delta(struct clock_event_device *dev)
234{
235 unsigned long long clc;
236 int64_t delta;
237 int i;
238
239 for (i = 0;;) {
240 delta = dev->min_delta_ns;
241 dev->next_event = ktime_add_ns(ktime_get(), delta);
242
243 if (clockevent_state_shutdown(dev))
244 return 0;
245
246 dev->retries++;
247 clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
248 if (dev->set_next_event((unsigned long) clc, dev) == 0)
249 return 0;
250
251 if (++i > 2) {
252 /*
253 * We tried 3 times to program the device with the
254 * given min_delta_ns. Try to increase the minimum
255 * delta, if that fails as well get out of here.
256 */
257 if (clockevents_increase_min_delta(dev))
258 return -ETIME;
259 i = 0;
260 }
261 }
262}
263
264#else /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */
265
266/**
267 * clockevents_program_min_delta - Set clock event device to the minimum delay.
268 * @dev: device to program
269 *
270 * Returns 0 on success, -ETIME when the retry loop failed.
271 */
272static int clockevents_program_min_delta(struct clock_event_device *dev)
273{
274 unsigned long long clc;
275 int64_t delta = 0;
276 int i;
277
278 for (i = 0; i < 10; i++) {
279 delta += dev->min_delta_ns;
280 dev->next_event = ktime_add_ns(ktime_get(), delta);
281
282 if (clockevent_state_shutdown(dev))
283 return 0;
284
285 dev->retries++;
286 clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
287 if (dev->set_next_event((unsigned long) clc, dev) == 0)
288 return 0;
289 }
290 return -ETIME;
291}
292
293#endif /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */
294
295/**
296 * clockevents_program_event - Reprogram the clock event device.
297 * @dev: device to program
298 * @expires: absolute expiry time (monotonic clock)
299 * @force: program minimum delay if expires can not be set
300 *
301 * Returns 0 on success, -ETIME when the event is in the past.
302 */
303int clockevents_program_event(struct clock_event_device *dev, ktime_t expires,
304 bool force)
305{
306 unsigned long long clc;
307 int64_t delta;
308 int rc;
309
310 if (WARN_ON_ONCE(expires < 0))
311 return -ETIME;
312
313 dev->next_event = expires;
314
315 if (clockevent_state_shutdown(dev))
316 return 0;
317
318 /* We must be in ONESHOT state here */
319 WARN_ONCE(!clockevent_state_oneshot(dev), "Current state: %d\n",
320 clockevent_get_state(dev));
321
322 /* Shortcut for clockevent devices that can deal with ktime. */
323 if (dev->features & CLOCK_EVT_FEAT_KTIME)
324 return dev->set_next_ktime(expires, dev);
325
326 delta = ktime_to_ns(ktime_sub(expires, ktime_get()));
327 if (delta <= 0)
328 return force ? clockevents_program_min_delta(dev) : -ETIME;
329
330 delta = min(delta, (int64_t) dev->max_delta_ns);
331 delta = max(delta, (int64_t) dev->min_delta_ns);
332
333 clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
334 rc = dev->set_next_event((unsigned long) clc, dev);
335
336 return (rc && force) ? clockevents_program_min_delta(dev) : rc;
337}
338
339/*
340 * Called after a notify add to make devices available which were
341 * released from the notifier call.
342 */
343static void clockevents_notify_released(void)
344{
345 struct clock_event_device *dev;
346
347 while (!list_empty(&clockevents_released)) {
348 dev = list_entry(clockevents_released.next,
349 struct clock_event_device, list);
350 list_move(&dev->list, &clockevent_devices);
351 tick_check_new_device(dev);
352 }
353}
354
355/*
356 * Try to install a replacement clock event device
357 */
358static int clockevents_replace(struct clock_event_device *ced)
359{
360 struct clock_event_device *dev, *newdev = NULL;
361
362 list_for_each_entry(dev, &clockevent_devices, list) {
363 if (dev == ced || !clockevent_state_detached(dev))
364 continue;
365
366 if (!tick_check_replacement(newdev, dev))
367 continue;
368
369 if (!try_module_get(dev->owner))
370 continue;
371
372 if (newdev)
373 module_put(newdev->owner);
374 newdev = dev;
375 }
376 if (newdev) {
377 tick_install_replacement(newdev);
378 list_del_init(&ced->list);
379 }
380 return newdev ? 0 : -EBUSY;
381}
382
383/*
384 * Called with clockevents_mutex and clockevents_lock held
385 */
386static int __clockevents_try_unbind(struct clock_event_device *ced, int cpu)
387{
388 /* Fast track. Device is unused */
389 if (clockevent_state_detached(ced)) {
390 list_del_init(&ced->list);
391 return 0;
392 }
393
394 return ced == per_cpu(tick_cpu_device, cpu).evtdev ? -EAGAIN : -EBUSY;
395}
396
397/*
398 * SMP function call to unbind a device
399 */
400static void __clockevents_unbind(void *arg)
401{
402 struct ce_unbind *cu = arg;
403 int res;
404
405 raw_spin_lock(&clockevents_lock);
406 res = __clockevents_try_unbind(cu->ce, smp_processor_id());
407 if (res == -EAGAIN)
408 res = clockevents_replace(cu->ce);
409 cu->res = res;
410 raw_spin_unlock(&clockevents_lock);
411}
412
413/*
414 * Issues smp function call to unbind a per cpu device. Called with
415 * clockevents_mutex held.
416 */
417static int clockevents_unbind(struct clock_event_device *ced, int cpu)
418{
419 struct ce_unbind cu = { .ce = ced, .res = -ENODEV };
420
421 smp_call_function_single(cpu, __clockevents_unbind, &cu, 1);
422 return cu.res;
423}
424
425/*
426 * Unbind a clockevents device.
427 */
428int clockevents_unbind_device(struct clock_event_device *ced, int cpu)
429{
430 int ret;
431
432 mutex_lock(&clockevents_mutex);
433 ret = clockevents_unbind(ced, cpu);
434 mutex_unlock(&clockevents_mutex);
435 return ret;
436}
437EXPORT_SYMBOL_GPL(clockevents_unbind_device);
438
439/**
440 * clockevents_register_device - register a clock event device
441 * @dev: device to register
442 */
443void clockevents_register_device(struct clock_event_device *dev)
444{
445 unsigned long flags;
446
447 /* Initialize state to DETACHED */
448 clockevent_set_state(dev, CLOCK_EVT_STATE_DETACHED);
449
450 if (!dev->cpumask) {
451 WARN_ON(num_possible_cpus() > 1);
452 dev->cpumask = cpumask_of(smp_processor_id());
453 }
454
455 if (dev->cpumask == cpu_all_mask) {
456 WARN(1, "%s cpumask == cpu_all_mask, using cpu_possible_mask instead\n",
457 dev->name);
458 dev->cpumask = cpu_possible_mask;
459 }
460
461 raw_spin_lock_irqsave(&clockevents_lock, flags);
462
463 list_add(&dev->list, &clockevent_devices);
464 tick_check_new_device(dev);
465 clockevents_notify_released();
466
467 raw_spin_unlock_irqrestore(&clockevents_lock, flags);
468}
469EXPORT_SYMBOL_GPL(clockevents_register_device);
470
471static void clockevents_config(struct clock_event_device *dev, u32 freq)
472{
473 u64 sec;
474
475 if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
476 return;
477
478 /*
479 * Calculate the maximum number of seconds we can sleep. Limit
480 * to 10 minutes for hardware which can program more than
481 * 32bit ticks so we still get reasonable conversion values.
482 */
483 sec = dev->max_delta_ticks;
484 do_div(sec, freq);
485 if (!sec)
486 sec = 1;
487 else if (sec > 600 && dev->max_delta_ticks > UINT_MAX)
488 sec = 600;
489
490 clockevents_calc_mult_shift(dev, freq, sec);
491 dev->min_delta_ns = cev_delta2ns(dev->min_delta_ticks, dev, false);
492 dev->max_delta_ns = cev_delta2ns(dev->max_delta_ticks, dev, true);
493}
494
495/**
496 * clockevents_config_and_register - Configure and register a clock event device
497 * @dev: device to register
498 * @freq: The clock frequency
499 * @min_delta: The minimum clock ticks to program in oneshot mode
500 * @max_delta: The maximum clock ticks to program in oneshot mode
501 *
502 * min/max_delta can be 0 for devices which do not support oneshot mode.
503 */
504void clockevents_config_and_register(struct clock_event_device *dev,
505 u32 freq, unsigned long min_delta,
506 unsigned long max_delta)
507{
508 dev->min_delta_ticks = min_delta;
509 dev->max_delta_ticks = max_delta;
510 clockevents_config(dev, freq);
511 clockevents_register_device(dev);
512}
513EXPORT_SYMBOL_GPL(clockevents_config_and_register);
514
515int __clockevents_update_freq(struct clock_event_device *dev, u32 freq)
516{
517 clockevents_config(dev, freq);
518
519 if (clockevent_state_oneshot(dev))
520 return clockevents_program_event(dev, dev->next_event, false);
521
522 if (clockevent_state_periodic(dev))
523 return __clockevents_switch_state(dev, CLOCK_EVT_STATE_PERIODIC);
524
525 return 0;
526}
527
528/**
529 * clockevents_update_freq - Update frequency and reprogram a clock event device.
530 * @dev: device to modify
531 * @freq: new device frequency
532 *
533 * Reconfigure and reprogram a clock event device in oneshot
534 * mode. Must be called on the cpu for which the device delivers per
535 * cpu timer events. If called for the broadcast device the core takes
536 * care of serialization.
537 *
538 * Returns 0 on success, -ETIME when the event is in the past.
539 */
540int clockevents_update_freq(struct clock_event_device *dev, u32 freq)
541{
542 unsigned long flags;
543 int ret;
544
545 local_irq_save(flags);
546 ret = tick_broadcast_update_freq(dev, freq);
547 if (ret == -ENODEV)
548 ret = __clockevents_update_freq(dev, freq);
549 local_irq_restore(flags);
550 return ret;
551}
552
553/*
554 * Noop handler when we shut down an event device
555 */
556void clockevents_handle_noop(struct clock_event_device *dev)
557{
558}
559
560/**
561 * clockevents_exchange_device - release and request clock devices
562 * @old: device to release (can be NULL)
563 * @new: device to request (can be NULL)
564 *
565 * Called from various tick functions with clockevents_lock held and
566 * interrupts disabled.
567 */
568void clockevents_exchange_device(struct clock_event_device *old,
569 struct clock_event_device *new)
570{
571 /*
572 * Caller releases a clock event device. We queue it into the
573 * released list and do a notify add later.
574 */
575 if (old) {
576 module_put(old->owner);
577 clockevents_switch_state(old, CLOCK_EVT_STATE_DETACHED);
578 list_move(&old->list, &clockevents_released);
579 }
580
581 if (new) {
582 BUG_ON(!clockevent_state_detached(new));
583 clockevents_shutdown(new);
584 }
585}
586
587/**
588 * clockevents_suspend - suspend clock devices
589 */
590void clockevents_suspend(void)
591{
592 struct clock_event_device *dev;
593
594 list_for_each_entry_reverse(dev, &clockevent_devices, list)
595 if (dev->suspend && !clockevent_state_detached(dev))
596 dev->suspend(dev);
597}
598
599/**
600 * clockevents_resume - resume clock devices
601 */
602void clockevents_resume(void)
603{
604 struct clock_event_device *dev;
605
606 list_for_each_entry(dev, &clockevent_devices, list)
607 if (dev->resume && !clockevent_state_detached(dev))
608 dev->resume(dev);
609}
610
611#ifdef CONFIG_HOTPLUG_CPU
612
613# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
614/**
615 * tick_offline_cpu - Take CPU out of the broadcast mechanism
616 * @cpu: The outgoing CPU
617 *
618 * Called on the outgoing CPU after it took itself offline.
619 */
620void tick_offline_cpu(unsigned int cpu)
621{
622 raw_spin_lock(&clockevents_lock);
623 tick_broadcast_offline(cpu);
624 raw_spin_unlock(&clockevents_lock);
625}
626# endif
627
628/**
629 * tick_cleanup_dead_cpu - Cleanup the tick and clockevents of a dead cpu
630 * @cpu: The dead CPU
631 */
632void tick_cleanup_dead_cpu(int cpu)
633{
634 struct clock_event_device *dev, *tmp;
635 unsigned long flags;
636
637 raw_spin_lock_irqsave(&clockevents_lock, flags);
638
639 tick_shutdown(cpu);
640 /*
641 * Unregister the clock event devices which were
642 * released from the users in the notify chain.
643 */
644 list_for_each_entry_safe(dev, tmp, &clockevents_released, list)
645 list_del(&dev->list);
646 /*
647 * Now check whether the CPU has left unused per cpu devices
648 */
649 list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) {
650 if (cpumask_test_cpu(cpu, dev->cpumask) &&
651 cpumask_weight(dev->cpumask) == 1 &&
652 !tick_is_broadcast_device(dev)) {
653 BUG_ON(!clockevent_state_detached(dev));
654 list_del(&dev->list);
655 }
656 }
657 raw_spin_unlock_irqrestore(&clockevents_lock, flags);
658}
659#endif
660
661#ifdef CONFIG_SYSFS
662static struct bus_type clockevents_subsys = {
663 .name = "clockevents",
664 .dev_name = "clockevent",
665};
666
667static DEFINE_PER_CPU(struct device, tick_percpu_dev);
668static struct tick_device *tick_get_tick_dev(struct device *dev);
669
670static ssize_t current_device_show(struct device *dev,
671 struct device_attribute *attr,
672 char *buf)
673{
674 struct tick_device *td;
675 ssize_t count = 0;
676
677 raw_spin_lock_irq(&clockevents_lock);
678 td = tick_get_tick_dev(dev);
679 if (td && td->evtdev)
680 count = snprintf(buf, PAGE_SIZE, "%s\n", td->evtdev->name);
681 raw_spin_unlock_irq(&clockevents_lock);
682 return count;
683}
684static DEVICE_ATTR_RO(current_device);
685
686/* We don't support the abomination of removable broadcast devices */
687static ssize_t unbind_device_store(struct device *dev,
688 struct device_attribute *attr,
689 const char *buf, size_t count)
690{
691 char name[CS_NAME_LEN];
692 ssize_t ret = sysfs_get_uname(buf, name, count);
693 struct clock_event_device *ce = NULL, *iter;
694
695 if (ret < 0)
696 return ret;
697
698 ret = -ENODEV;
699 mutex_lock(&clockevents_mutex);
700 raw_spin_lock_irq(&clockevents_lock);
701 list_for_each_entry(iter, &clockevent_devices, list) {
702 if (!strcmp(iter->name, name)) {
703 ret = __clockevents_try_unbind(iter, dev->id);
704 ce = iter;
705 break;
706 }
707 }
708 raw_spin_unlock_irq(&clockevents_lock);
709 /*
710 * We hold clockevents_mutex, so ce can't go away
711 */
712 if (ret == -EAGAIN)
713 ret = clockevents_unbind(ce, dev->id);
714 mutex_unlock(&clockevents_mutex);
715 return ret ? ret : count;
716}
717static DEVICE_ATTR_WO(unbind_device);
718
719#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
720static struct device tick_bc_dev = {
721 .init_name = "broadcast",
722 .id = 0,
723 .bus = &clockevents_subsys,
724};
725
726static struct tick_device *tick_get_tick_dev(struct device *dev)
727{
728 return dev == &tick_bc_dev ? tick_get_broadcast_device() :
729 &per_cpu(tick_cpu_device, dev->id);
730}
731
732static __init int tick_broadcast_init_sysfs(void)
733{
734 int err = device_register(&tick_bc_dev);
735
736 if (!err)
737 err = device_create_file(&tick_bc_dev, &dev_attr_current_device);
738 return err;
739}
740#else
741static struct tick_device *tick_get_tick_dev(struct device *dev)
742{
743 return &per_cpu(tick_cpu_device, dev->id);
744}
745static inline int tick_broadcast_init_sysfs(void) { return 0; }
746#endif
747
748static int __init tick_init_sysfs(void)
749{
750 int cpu;
751
752 for_each_possible_cpu(cpu) {
753 struct device *dev = &per_cpu(tick_percpu_dev, cpu);
754 int err;
755
756 dev->id = cpu;
757 dev->bus = &clockevents_subsys;
758 err = device_register(dev);
759 if (!err)
760 err = device_create_file(dev, &dev_attr_current_device);
761 if (!err)
762 err = device_create_file(dev, &dev_attr_unbind_device);
763 if (err)
764 return err;
765 }
766 return tick_broadcast_init_sysfs();
767}
768
769static int __init clockevents_init_sysfs(void)
770{
771 int err = subsys_system_register(&clockevents_subsys, NULL);
772
773 if (!err)
774 err = tick_init_sysfs();
775 return err;
776}
777device_initcall(clockevents_init_sysfs);
778#endif /* SYSFS */