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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
20static LIST_HEAD(clockevent_devices);
21static LIST_HEAD(clockevents_released);
22
23static DEFINE_RAW_SPINLOCK(clockevents_lock);
24
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
44
45
46 if ((clc >> evt->shift) != (u64)latch)
47 clc = ~0ULL;
48
49
50
51
52
53
54
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57
58
59
60
61
62
63
64
65
66
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
75 return clc > 1000 ? clc : 1000;
76}
77
78
79
80
81
82
83
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
98 switch (state) {
99 case CLOCK_EVT_STATE_DETACHED:
100
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
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
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
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
142
143
144
145
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
158
159
160 if (clockevent_state_oneshot(dev)) {
161 if (WARN_ON(!dev->mult))
162 dev->mult = 1;
163 }
164 }
165}
166
167
168
169
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
179
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
194#define MIN_DELTA_LIMIT (NSEC_PER_SEC / HZ)
195
196
197
198
199
200
201
202static int clockevents_increase_min_delta(struct clock_event_device *dev)
203{
204
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
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230
231
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
254
255
256
257 if (clockevents_increase_min_delta(dev))
258 return -ETIME;
259 i = 0;
260 }
261 }
262}
263
264#else
265
266
267
268
269
270
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
294
295
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299
300
301
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
319 WARN_ONCE(!clockevent_state_oneshot(dev), "Current state: %d\n",
320 clockevent_get_state(dev));
321
322
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
341
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
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
386
387static int __clockevents_try_unbind(struct clock_event_device *ced, int cpu)
388{
389
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
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
416
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
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
442
443
444void clockevents_register_device(struct clock_event_device *dev)
445{
446 unsigned long flags;
447
448
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
481
482
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
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500
501
502
503
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
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539
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
556
557void clockevents_handle_noop(struct clock_event_device *dev)
558{
559}
560
561
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564
565
566
567
568
569void clockevents_exchange_device(struct clock_event_device *old,
570 struct clock_event_device *new)
571{
572
573
574
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
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
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
618
619
620
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
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
643
644
645 list_for_each_entry_safe(dev, tmp, &clockevents_released, list)
646 list_del(&dev->list);
647
648
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
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
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
779