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14#include <linux/clockchips.h>
15#include <linux/hrtimer.h>
16#include <linux/init.h>
17#include <linux/module.h>
18#include <linux/smp.h>
19#include <linux/device.h>
20
21#include "tick-internal.h"
22
23
24static LIST_HEAD(clockevent_devices);
25static LIST_HEAD(clockevents_released);
26
27static DEFINE_RAW_SPINLOCK(clockevents_lock);
28
29static DEFINE_MUTEX(clockevents_mutex);
30
31struct ce_unbind {
32 struct clock_event_device *ce;
33 int res;
34};
35
36static u64 cev_delta2ns(unsigned long latch, struct clock_event_device *evt,
37 bool ismax)
38{
39 u64 clc = (u64) latch << evt->shift;
40 u64 rnd;
41
42 if (unlikely(!evt->mult)) {
43 evt->mult = 1;
44 WARN_ON(1);
45 }
46 rnd = (u64) evt->mult - 1;
47
48
49
50
51
52 if ((clc >> evt->shift) != (u64)latch)
53 clc = ~0ULL;
54
55
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71
72
73
74 if ((~0ULL - clc > rnd) &&
75 (!ismax || evt->mult <= (1U << evt->shift)))
76 clc += rnd;
77
78 do_div(clc, evt->mult);
79
80
81 return clc > 1000 ? clc : 1000;
82}
83
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90
91u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt)
92{
93 return cev_delta2ns(latch, evt, false);
94}
95EXPORT_SYMBOL_GPL(clockevent_delta2ns);
96
97
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100
101
102
103
104void clockevents_set_mode(struct clock_event_device *dev,
105 enum clock_event_mode mode)
106{
107 if (dev->mode != mode) {
108 dev->set_mode(mode, dev);
109 dev->mode = mode;
110
111
112
113
114
115 if (mode == CLOCK_EVT_MODE_ONESHOT) {
116 if (unlikely(!dev->mult)) {
117 dev->mult = 1;
118 WARN_ON(1);
119 }
120 }
121 }
122}
123
124
125
126
127
128void clockevents_shutdown(struct clock_event_device *dev)
129{
130 clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
131 dev->next_event.tv64 = KTIME_MAX;
132}
133
134#ifdef CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST
135
136
137#define MIN_DELTA_LIMIT (NSEC_PER_SEC / HZ)
138
139
140
141
142
143
144
145static int clockevents_increase_min_delta(struct clock_event_device *dev)
146{
147
148 if (dev->min_delta_ns >= MIN_DELTA_LIMIT) {
149 printk(KERN_WARNING "CE: Reprogramming failure. Giving up\n");
150 dev->next_event.tv64 = KTIME_MAX;
151 return -ETIME;
152 }
153
154 if (dev->min_delta_ns < 5000)
155 dev->min_delta_ns = 5000;
156 else
157 dev->min_delta_ns += dev->min_delta_ns >> 1;
158
159 if (dev->min_delta_ns > MIN_DELTA_LIMIT)
160 dev->min_delta_ns = MIN_DELTA_LIMIT;
161
162 printk(KERN_WARNING "CE: %s increased min_delta_ns to %llu nsec\n",
163 dev->name ? dev->name : "?",
164 (unsigned long long) dev->min_delta_ns);
165 return 0;
166}
167
168
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171
172
173
174static int clockevents_program_min_delta(struct clock_event_device *dev)
175{
176 unsigned long long clc;
177 int64_t delta;
178 int i;
179
180 for (i = 0;;) {
181 delta = dev->min_delta_ns;
182 dev->next_event = ktime_add_ns(ktime_get(), delta);
183
184 if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
185 return 0;
186
187 dev->retries++;
188 clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
189 if (dev->set_next_event((unsigned long) clc, dev) == 0)
190 return 0;
191
192 if (++i > 2) {
193
194
195
196
197
198 if (clockevents_increase_min_delta(dev))
199 return -ETIME;
200 i = 0;
201 }
202 }
203}
204
205#else
206
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211
212
213static int clockevents_program_min_delta(struct clock_event_device *dev)
214{
215 unsigned long long clc;
216 int64_t delta;
217
218 delta = dev->min_delta_ns;
219 dev->next_event = ktime_add_ns(ktime_get(), delta);
220
221 if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
222 return 0;
223
224 dev->retries++;
225 clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
226 return dev->set_next_event((unsigned long) clc, dev);
227}
228
229#endif
230
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237
238
239int clockevents_program_event(struct clock_event_device *dev, ktime_t expires,
240 bool force)
241{
242 unsigned long long clc;
243 int64_t delta;
244 int rc;
245
246 if (unlikely(expires.tv64 < 0)) {
247 WARN_ON_ONCE(1);
248 return -ETIME;
249 }
250
251 dev->next_event = expires;
252
253 if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
254 return 0;
255
256
257 if (dev->features & CLOCK_EVT_FEAT_KTIME)
258 return dev->set_next_ktime(expires, dev);
259
260 delta = ktime_to_ns(ktime_sub(expires, ktime_get()));
261 if (delta <= 0)
262 return force ? clockevents_program_min_delta(dev) : -ETIME;
263
264 delta = min(delta, (int64_t) dev->max_delta_ns);
265 delta = max(delta, (int64_t) dev->min_delta_ns);
266
267 clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
268 rc = dev->set_next_event((unsigned long) clc, dev);
269
270 return (rc && force) ? clockevents_program_min_delta(dev) : rc;
271}
272
273
274
275
276
277static void clockevents_notify_released(void)
278{
279 struct clock_event_device *dev;
280
281 while (!list_empty(&clockevents_released)) {
282 dev = list_entry(clockevents_released.next,
283 struct clock_event_device, list);
284 list_del(&dev->list);
285 list_add(&dev->list, &clockevent_devices);
286 tick_check_new_device(dev);
287 }
288}
289
290
291
292
293static int clockevents_replace(struct clock_event_device *ced)
294{
295 struct clock_event_device *dev, *newdev = NULL;
296
297 list_for_each_entry(dev, &clockevent_devices, list) {
298 if (dev == ced || dev->mode != CLOCK_EVT_MODE_UNUSED)
299 continue;
300
301 if (!tick_check_replacement(newdev, dev))
302 continue;
303
304 if (!try_module_get(dev->owner))
305 continue;
306
307 if (newdev)
308 module_put(newdev->owner);
309 newdev = dev;
310 }
311 if (newdev) {
312 tick_install_replacement(newdev);
313 list_del_init(&ced->list);
314 }
315 return newdev ? 0 : -EBUSY;
316}
317
318
319
320
321static int __clockevents_try_unbind(struct clock_event_device *ced, int cpu)
322{
323
324 if (ced->mode == CLOCK_EVT_MODE_UNUSED) {
325 list_del_init(&ced->list);
326 return 0;
327 }
328
329 return ced == per_cpu(tick_cpu_device, cpu).evtdev ? -EAGAIN : -EBUSY;
330}
331
332
333
334
335static void __clockevents_unbind(void *arg)
336{
337 struct ce_unbind *cu = arg;
338 int res;
339
340 raw_spin_lock(&clockevents_lock);
341 res = __clockevents_try_unbind(cu->ce, smp_processor_id());
342 if (res == -EAGAIN)
343 res = clockevents_replace(cu->ce);
344 cu->res = res;
345 raw_spin_unlock(&clockevents_lock);
346}
347
348
349
350
351
352static int clockevents_unbind(struct clock_event_device *ced, int cpu)
353{
354 struct ce_unbind cu = { .ce = ced, .res = -ENODEV };
355
356 smp_call_function_single(cpu, __clockevents_unbind, &cu, 1);
357 return cu.res;
358}
359
360
361
362
363int clockevents_unbind_device(struct clock_event_device *ced, int cpu)
364{
365 int ret;
366
367 mutex_lock(&clockevents_mutex);
368 ret = clockevents_unbind(ced, cpu);
369 mutex_unlock(&clockevents_mutex);
370 return ret;
371}
372EXPORT_SYMBOL_GPL(clockevents_unbind);
373
374
375
376
377
378void clockevents_register_device(struct clock_event_device *dev)
379{
380 unsigned long flags;
381
382 BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
383 if (!dev->cpumask) {
384 WARN_ON(num_possible_cpus() > 1);
385 dev->cpumask = cpumask_of(smp_processor_id());
386 }
387
388 raw_spin_lock_irqsave(&clockevents_lock, flags);
389
390 list_add(&dev->list, &clockevent_devices);
391 tick_check_new_device(dev);
392 clockevents_notify_released();
393
394 raw_spin_unlock_irqrestore(&clockevents_lock, flags);
395}
396EXPORT_SYMBOL_GPL(clockevents_register_device);
397
398void clockevents_config(struct clock_event_device *dev, u32 freq)
399{
400 u64 sec;
401
402 if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
403 return;
404
405
406
407
408
409
410 sec = dev->max_delta_ticks;
411 do_div(sec, freq);
412 if (!sec)
413 sec = 1;
414 else if (sec > 600 && dev->max_delta_ticks > UINT_MAX)
415 sec = 600;
416
417 clockevents_calc_mult_shift(dev, freq, sec);
418 dev->min_delta_ns = cev_delta2ns(dev->min_delta_ticks, dev, false);
419 dev->max_delta_ns = cev_delta2ns(dev->max_delta_ticks, dev, true);
420}
421
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425
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429
430
431void clockevents_config_and_register(struct clock_event_device *dev,
432 u32 freq, unsigned long min_delta,
433 unsigned long max_delta)
434{
435 dev->min_delta_ticks = min_delta;
436 dev->max_delta_ticks = max_delta;
437 clockevents_config(dev, freq);
438 clockevents_register_device(dev);
439}
440EXPORT_SYMBOL_GPL(clockevents_config_and_register);
441
442int __clockevents_update_freq(struct clock_event_device *dev, u32 freq)
443{
444 clockevents_config(dev, freq);
445
446 if (dev->mode == CLOCK_EVT_MODE_ONESHOT)
447 return clockevents_program_event(dev, dev->next_event, false);
448
449 if (dev->mode == CLOCK_EVT_MODE_PERIODIC)
450 dev->set_mode(CLOCK_EVT_MODE_PERIODIC, dev);
451
452 return 0;
453}
454
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465
466
467int clockevents_update_freq(struct clock_event_device *dev, u32 freq)
468{
469 unsigned long flags;
470 int ret;
471
472 local_irq_save(flags);
473 ret = tick_broadcast_update_freq(dev, freq);
474 if (ret == -ENODEV)
475 ret = __clockevents_update_freq(dev, freq);
476 local_irq_restore(flags);
477 return ret;
478}
479
480
481
482
483void clockevents_handle_noop(struct clock_event_device *dev)
484{
485}
486
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488
489
490
491
492
493
494void clockevents_exchange_device(struct clock_event_device *old,
495 struct clock_event_device *new)
496{
497 unsigned long flags;
498
499 local_irq_save(flags);
500
501
502
503
504 if (old) {
505 module_put(old->owner);
506 clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED);
507 list_del(&old->list);
508 list_add(&old->list, &clockevents_released);
509 }
510
511 if (new) {
512 BUG_ON(new->mode != CLOCK_EVT_MODE_UNUSED);
513 clockevents_shutdown(new);
514 }
515 local_irq_restore(flags);
516}
517
518
519
520
521void clockevents_suspend(void)
522{
523 struct clock_event_device *dev;
524
525 list_for_each_entry_reverse(dev, &clockevent_devices, list)
526 if (dev->suspend)
527 dev->suspend(dev);
528}
529
530
531
532
533void clockevents_resume(void)
534{
535 struct clock_event_device *dev;
536
537 list_for_each_entry(dev, &clockevent_devices, list)
538 if (dev->resume)
539 dev->resume(dev);
540}
541
542#ifdef CONFIG_GENERIC_CLOCKEVENTS
543
544
545
546
547int clockevents_notify(unsigned long reason, void *arg)
548{
549 struct clock_event_device *dev, *tmp;
550 unsigned long flags;
551 int cpu, ret = 0;
552
553 raw_spin_lock_irqsave(&clockevents_lock, flags);
554
555 switch (reason) {
556 case CLOCK_EVT_NOTIFY_BROADCAST_ON:
557 case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
558 case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
559 tick_broadcast_on_off(reason, arg);
560 break;
561
562 case CLOCK_EVT_NOTIFY_BROADCAST_ENTER:
563 case CLOCK_EVT_NOTIFY_BROADCAST_EXIT:
564 ret = tick_broadcast_oneshot_control(reason);
565 break;
566
567 case CLOCK_EVT_NOTIFY_CPU_DYING:
568 tick_handover_do_timer(arg);
569 break;
570
571 case CLOCK_EVT_NOTIFY_SUSPEND:
572 tick_suspend();
573 tick_suspend_broadcast();
574 break;
575
576 case CLOCK_EVT_NOTIFY_RESUME:
577 tick_resume();
578 break;
579
580 case CLOCK_EVT_NOTIFY_CPU_DEAD:
581 tick_shutdown_broadcast_oneshot(arg);
582 tick_shutdown_broadcast(arg);
583 tick_shutdown(arg);
584
585
586
587
588 list_for_each_entry_safe(dev, tmp, &clockevents_released, list)
589 list_del(&dev->list);
590
591
592
593 cpu = *((int *)arg);
594 list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) {
595 if (cpumask_test_cpu(cpu, dev->cpumask) &&
596 cpumask_weight(dev->cpumask) == 1 &&
597 !tick_is_broadcast_device(dev)) {
598 BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
599 list_del(&dev->list);
600 }
601 }
602 break;
603 default:
604 break;
605 }
606 raw_spin_unlock_irqrestore(&clockevents_lock, flags);
607 return ret;
608}
609EXPORT_SYMBOL_GPL(clockevents_notify);
610
611#ifdef CONFIG_SYSFS
612struct bus_type clockevents_subsys = {
613 .name = "clockevents",
614 .dev_name = "clockevent",
615};
616
617static DEFINE_PER_CPU(struct device, tick_percpu_dev);
618static struct tick_device *tick_get_tick_dev(struct device *dev);
619
620static ssize_t sysfs_show_current_tick_dev(struct device *dev,
621 struct device_attribute *attr,
622 char *buf)
623{
624 struct tick_device *td;
625 ssize_t count = 0;
626
627 raw_spin_lock_irq(&clockevents_lock);
628 td = tick_get_tick_dev(dev);
629 if (td && td->evtdev)
630 count = snprintf(buf, PAGE_SIZE, "%s\n", td->evtdev->name);
631 raw_spin_unlock_irq(&clockevents_lock);
632 return count;
633}
634static DEVICE_ATTR(current_device, 0444, sysfs_show_current_tick_dev, NULL);
635
636
637static ssize_t sysfs_unbind_tick_dev(struct device *dev,
638 struct device_attribute *attr,
639 const char *buf, size_t count)
640{
641 char name[CS_NAME_LEN];
642 ssize_t ret = sysfs_get_uname(buf, name, count);
643 struct clock_event_device *ce;
644
645 if (ret < 0)
646 return ret;
647
648 ret = -ENODEV;
649 mutex_lock(&clockevents_mutex);
650 raw_spin_lock_irq(&clockevents_lock);
651 list_for_each_entry(ce, &clockevent_devices, list) {
652 if (!strcmp(ce->name, name)) {
653 ret = __clockevents_try_unbind(ce, dev->id);
654 break;
655 }
656 }
657 raw_spin_unlock_irq(&clockevents_lock);
658
659
660
661 if (ret == -EAGAIN)
662 ret = clockevents_unbind(ce, dev->id);
663 mutex_unlock(&clockevents_mutex);
664 return ret ? ret : count;
665}
666static DEVICE_ATTR(unbind_device, 0200, NULL, sysfs_unbind_tick_dev);
667
668#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
669static struct device tick_bc_dev = {
670 .init_name = "broadcast",
671 .id = 0,
672 .bus = &clockevents_subsys,
673};
674
675static struct tick_device *tick_get_tick_dev(struct device *dev)
676{
677 return dev == &tick_bc_dev ? tick_get_broadcast_device() :
678 &per_cpu(tick_cpu_device, dev->id);
679}
680
681static __init int tick_broadcast_init_sysfs(void)
682{
683 int err = device_register(&tick_bc_dev);
684
685 if (!err)
686 err = device_create_file(&tick_bc_dev, &dev_attr_current_device);
687 return err;
688}
689#else
690static struct tick_device *tick_get_tick_dev(struct device *dev)
691{
692 return &per_cpu(tick_cpu_device, dev->id);
693}
694static inline int tick_broadcast_init_sysfs(void) { return 0; }
695#endif
696
697static int __init tick_init_sysfs(void)
698{
699 int cpu;
700
701 for_each_possible_cpu(cpu) {
702 struct device *dev = &per_cpu(tick_percpu_dev, cpu);
703 int err;
704
705 dev->id = cpu;
706 dev->bus = &clockevents_subsys;
707 err = device_register(dev);
708 if (!err)
709 err = device_create_file(dev, &dev_attr_current_device);
710 if (!err)
711 err = device_create_file(dev, &dev_attr_unbind_device);
712 if (err)
713 return err;
714 }
715 return tick_broadcast_init_sysfs();
716}
717
718static int __init clockevents_init_sysfs(void)
719{
720 int err = subsys_system_register(&clockevents_subsys, NULL);
721
722 if (!err)
723 err = tick_init_sysfs();
724 return err;
725}
726device_initcall(clockevents_init_sysfs);
727#endif
728
729#endif
730