Commit | Line | Data |
---|---|---|
d316c57f TG |
1 | /* |
2 | * linux/kernel/time/clockevents.c | |
3 | * | |
4 | * This file contains functions which manage clock event devices. | |
5 | * | |
6 | * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de> | |
7 | * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar | |
8 | * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner | |
9 | * | |
10 | * This code is licenced under the GPL version 2. For details see | |
11 | * kernel-base/COPYING. | |
12 | */ | |
13 | ||
14 | #include <linux/clockchips.h> | |
15 | #include <linux/hrtimer.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/module.h> | |
d316c57f | 18 | #include <linux/smp.h> |
501f8670 | 19 | #include <linux/device.h> |
d316c57f | 20 | |
8e1a928a HS |
21 | #include "tick-internal.h" |
22 | ||
d316c57f TG |
23 | /* The registered clock event devices */ |
24 | static LIST_HEAD(clockevent_devices); | |
25 | static LIST_HEAD(clockevents_released); | |
d316c57f | 26 | /* Protection for the above */ |
b5f91da0 | 27 | static DEFINE_RAW_SPINLOCK(clockevents_lock); |
03e13cf5 TG |
28 | /* Protection for unbind operations */ |
29 | static DEFINE_MUTEX(clockevents_mutex); | |
30 | ||
31 | struct ce_unbind { | |
32 | struct clock_event_device *ce; | |
33 | int res; | |
34 | }; | |
d316c57f | 35 | |
97b94106 TG |
36 | static u64 cev_delta2ns(unsigned long latch, struct clock_event_device *evt, |
37 | bool ismax) | |
d316c57f | 38 | { |
97813f2f | 39 | u64 clc = (u64) latch << evt->shift; |
97b94106 | 40 | u64 rnd; |
d316c57f | 41 | |
45fe4fe1 IM |
42 | if (unlikely(!evt->mult)) { |
43 | evt->mult = 1; | |
44 | WARN_ON(1); | |
45 | } | |
97b94106 TG |
46 | rnd = (u64) evt->mult - 1; |
47 | ||
48 | /* | |
49 | * Upper bound sanity check. If the backwards conversion is | |
50 | * not equal latch, we know that the above shift overflowed. | |
51 | */ | |
52 | if ((clc >> evt->shift) != (u64)latch) | |
53 | clc = ~0ULL; | |
54 | ||
55 | /* | |
56 | * Scaled math oddities: | |
57 | * | |
58 | * For mult <= (1 << shift) we can safely add mult - 1 to | |
59 | * prevent integer rounding loss. So the backwards conversion | |
60 | * from nsec to device ticks will be correct. | |
61 | * | |
62 | * For mult > (1 << shift), i.e. device frequency is > 1GHz we | |
63 | * need to be careful. Adding mult - 1 will result in a value | |
64 | * which when converted back to device ticks can be larger | |
65 | * than latch by up to (mult - 1) >> shift. For the min_delta | |
66 | * calculation we still want to apply this in order to stay | |
67 | * above the minimum device ticks limit. For the upper limit | |
68 | * we would end up with a latch value larger than the upper | |
69 | * limit of the device, so we omit the add to stay below the | |
70 | * device upper boundary. | |
71 | * | |
72 | * Also omit the add if it would overflow the u64 boundary. | |
73 | */ | |
74 | if ((~0ULL - clc > rnd) && | |
10632008 | 75 | (!ismax || evt->mult <= (1ULL << evt->shift))) |
97b94106 | 76 | clc += rnd; |
45fe4fe1 | 77 | |
d316c57f | 78 | do_div(clc, evt->mult); |
d316c57f | 79 | |
97b94106 TG |
80 | /* Deltas less than 1usec are pointless noise */ |
81 | return clc > 1000 ? clc : 1000; | |
82 | } | |
83 | ||
84 | /** | |
85 | * clockevents_delta2ns - Convert a latch value (device ticks) to nanoseconds | |
86 | * @latch: value to convert | |
87 | * @evt: pointer to clock event device descriptor | |
88 | * | |
89 | * Math helper, returns latch value converted to nanoseconds (bound checked) | |
90 | */ | |
91 | u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt) | |
92 | { | |
93 | return cev_delta2ns(latch, evt, false); | |
d316c57f | 94 | } |
c81fc2c3 | 95 | EXPORT_SYMBOL_GPL(clockevent_delta2ns); |
d316c57f | 96 | |
d7eb231c TG |
97 | static int __clockevents_switch_state(struct clock_event_device *dev, |
98 | enum clock_event_state state) | |
bd624d75 | 99 | { |
bd624d75 VK |
100 | if (dev->features & CLOCK_EVT_FEAT_DUMMY) |
101 | return 0; | |
102 | ||
77e32c89 VK |
103 | /* Transition with new state-specific callbacks */ |
104 | switch (state) { | |
105 | case CLOCK_EVT_STATE_DETACHED: | |
149aabcc | 106 | /* The clockevent device is getting replaced. Shut it down. */ |
bd624d75 | 107 | |
77e32c89 | 108 | case CLOCK_EVT_STATE_SHUTDOWN: |
7c4a976c VK |
109 | if (dev->set_state_shutdown) |
110 | return dev->set_state_shutdown(dev); | |
111 | return 0; | |
bd624d75 | 112 | |
77e32c89 | 113 | case CLOCK_EVT_STATE_PERIODIC: |
bd624d75 VK |
114 | /* Core internal bug */ |
115 | if (!(dev->features & CLOCK_EVT_FEAT_PERIODIC)) | |
116 | return -ENOSYS; | |
7c4a976c VK |
117 | if (dev->set_state_periodic) |
118 | return dev->set_state_periodic(dev); | |
119 | return 0; | |
bd624d75 | 120 | |
77e32c89 | 121 | case CLOCK_EVT_STATE_ONESHOT: |
bd624d75 VK |
122 | /* Core internal bug */ |
123 | if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT)) | |
124 | return -ENOSYS; | |
7c4a976c VK |
125 | if (dev->set_state_oneshot) |
126 | return dev->set_state_oneshot(dev); | |
127 | return 0; | |
bd624d75 | 128 | |
8fff52fd VK |
129 | case CLOCK_EVT_STATE_ONESHOT_STOPPED: |
130 | /* Core internal bug */ | |
472c4a94 | 131 | if (WARN_ONCE(!clockevent_state_oneshot(dev), |
051ebd10 TG |
132 | "Current state: %d\n", |
133 | clockevent_get_state(dev))) | |
8fff52fd VK |
134 | return -EINVAL; |
135 | ||
136 | if (dev->set_state_oneshot_stopped) | |
137 | return dev->set_state_oneshot_stopped(dev); | |
138 | else | |
139 | return -ENOSYS; | |
140 | ||
bd624d75 VK |
141 | default: |
142 | return -ENOSYS; | |
143 | } | |
144 | } | |
145 | ||
d316c57f | 146 | /** |
d7eb231c | 147 | * clockevents_switch_state - set the operating state of a clock event device |
d316c57f | 148 | * @dev: device to modify |
77e32c89 | 149 | * @state: new state |
d316c57f TG |
150 | * |
151 | * Must be called with interrupts disabled ! | |
152 | */ | |
d7eb231c TG |
153 | void clockevents_switch_state(struct clock_event_device *dev, |
154 | enum clock_event_state state) | |
d316c57f | 155 | { |
051ebd10 | 156 | if (clockevent_get_state(dev) != state) { |
d7eb231c | 157 | if (__clockevents_switch_state(dev, state)) |
bd624d75 VK |
158 | return; |
159 | ||
051ebd10 | 160 | clockevent_set_state(dev, state); |
2d68259d MD |
161 | |
162 | /* | |
163 | * A nsec2cyc multiplicator of 0 is invalid and we'd crash | |
164 | * on it, so fix it up and emit a warning: | |
165 | */ | |
472c4a94 | 166 | if (clockevent_state_oneshot(dev)) { |
2d68259d MD |
167 | if (unlikely(!dev->mult)) { |
168 | dev->mult = 1; | |
169 | WARN_ON(1); | |
170 | } | |
171 | } | |
d316c57f TG |
172 | } |
173 | } | |
174 | ||
2344abbc TG |
175 | /** |
176 | * clockevents_shutdown - shutdown the device and clear next_event | |
177 | * @dev: device to shutdown | |
178 | */ | |
179 | void clockevents_shutdown(struct clock_event_device *dev) | |
180 | { | |
d7eb231c | 181 | clockevents_switch_state(dev, CLOCK_EVT_STATE_SHUTDOWN); |
2344abbc TG |
182 | dev->next_event.tv64 = KTIME_MAX; |
183 | } | |
184 | ||
554ef387 VK |
185 | /** |
186 | * clockevents_tick_resume - Resume the tick device before using it again | |
187 | * @dev: device to resume | |
188 | */ | |
189 | int clockevents_tick_resume(struct clock_event_device *dev) | |
190 | { | |
191 | int ret = 0; | |
192 | ||
eef7635a | 193 | if (dev->tick_resume) |
77e32c89 | 194 | ret = dev->tick_resume(dev); |
554ef387 VK |
195 | |
196 | return ret; | |
197 | } | |
198 | ||
d1748302 MS |
199 | #ifdef CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST |
200 | ||
201 | /* Limit min_delta to a jiffie */ | |
202 | #define MIN_DELTA_LIMIT (NSEC_PER_SEC / HZ) | |
203 | ||
204 | /** | |
205 | * clockevents_increase_min_delta - raise minimum delta of a clock event device | |
206 | * @dev: device to increase the minimum delta | |
207 | * | |
208 | * Returns 0 on success, -ETIME when the minimum delta reached the limit. | |
209 | */ | |
210 | static int clockevents_increase_min_delta(struct clock_event_device *dev) | |
211 | { | |
212 | /* Nothing to do if we already reached the limit */ | |
213 | if (dev->min_delta_ns >= MIN_DELTA_LIMIT) { | |
504d5874 JK |
214 | printk_deferred(KERN_WARNING |
215 | "CE: Reprogramming failure. Giving up\n"); | |
d1748302 MS |
216 | dev->next_event.tv64 = KTIME_MAX; |
217 | return -ETIME; | |
218 | } | |
219 | ||
220 | if (dev->min_delta_ns < 5000) | |
221 | dev->min_delta_ns = 5000; | |
222 | else | |
223 | dev->min_delta_ns += dev->min_delta_ns >> 1; | |
224 | ||
225 | if (dev->min_delta_ns > MIN_DELTA_LIMIT) | |
226 | dev->min_delta_ns = MIN_DELTA_LIMIT; | |
227 | ||
504d5874 JK |
228 | printk_deferred(KERN_WARNING |
229 | "CE: %s increased min_delta_ns to %llu nsec\n", | |
230 | dev->name ? dev->name : "?", | |
231 | (unsigned long long) dev->min_delta_ns); | |
d1748302 MS |
232 | return 0; |
233 | } | |
234 | ||
235 | /** | |
236 | * clockevents_program_min_delta - Set clock event device to the minimum delay. | |
237 | * @dev: device to program | |
238 | * | |
239 | * Returns 0 on success, -ETIME when the retry loop failed. | |
240 | */ | |
241 | static int clockevents_program_min_delta(struct clock_event_device *dev) | |
242 | { | |
243 | unsigned long long clc; | |
244 | int64_t delta; | |
245 | int i; | |
246 | ||
247 | for (i = 0;;) { | |
248 | delta = dev->min_delta_ns; | |
249 | dev->next_event = ktime_add_ns(ktime_get(), delta); | |
250 | ||
472c4a94 | 251 | if (clockevent_state_shutdown(dev)) |
d1748302 MS |
252 | return 0; |
253 | ||
254 | dev->retries++; | |
255 | clc = ((unsigned long long) delta * dev->mult) >> dev->shift; | |
256 | if (dev->set_next_event((unsigned long) clc, dev) == 0) | |
257 | return 0; | |
258 | ||
259 | if (++i > 2) { | |
260 | /* | |
261 | * We tried 3 times to program the device with the | |
262 | * given min_delta_ns. Try to increase the minimum | |
263 | * delta, if that fails as well get out of here. | |
264 | */ | |
265 | if (clockevents_increase_min_delta(dev)) | |
266 | return -ETIME; | |
267 | i = 0; | |
268 | } | |
269 | } | |
270 | } | |
271 | ||
272 | #else /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */ | |
273 | ||
274 | /** | |
275 | * clockevents_program_min_delta - Set clock event device to the minimum delay. | |
276 | * @dev: device to program | |
277 | * | |
278 | * Returns 0 on success, -ETIME when the retry loop failed. | |
279 | */ | |
280 | static int clockevents_program_min_delta(struct clock_event_device *dev) | |
281 | { | |
282 | unsigned long long clc; | |
283 | int64_t delta; | |
284 | ||
285 | delta = dev->min_delta_ns; | |
286 | dev->next_event = ktime_add_ns(ktime_get(), delta); | |
287 | ||
472c4a94 | 288 | if (clockevent_state_shutdown(dev)) |
d1748302 MS |
289 | return 0; |
290 | ||
291 | dev->retries++; | |
292 | clc = ((unsigned long long) delta * dev->mult) >> dev->shift; | |
293 | return dev->set_next_event((unsigned long) clc, dev); | |
294 | } | |
295 | ||
296 | #endif /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */ | |
297 | ||
d316c57f TG |
298 | /** |
299 | * clockevents_program_event - Reprogram the clock event device. | |
d1748302 | 300 | * @dev: device to program |
d316c57f | 301 | * @expires: absolute expiry time (monotonic clock) |
d1748302 | 302 | * @force: program minimum delay if expires can not be set |
d316c57f TG |
303 | * |
304 | * Returns 0 on success, -ETIME when the event is in the past. | |
305 | */ | |
306 | int clockevents_program_event(struct clock_event_device *dev, ktime_t expires, | |
d1748302 | 307 | bool force) |
d316c57f TG |
308 | { |
309 | unsigned long long clc; | |
310 | int64_t delta; | |
d1748302 | 311 | int rc; |
d316c57f | 312 | |
167b1de3 TG |
313 | if (unlikely(expires.tv64 < 0)) { |
314 | WARN_ON_ONCE(1); | |
315 | return -ETIME; | |
316 | } | |
317 | ||
d316c57f TG |
318 | dev->next_event = expires; |
319 | ||
472c4a94 | 320 | if (clockevent_state_shutdown(dev)) |
d316c57f TG |
321 | return 0; |
322 | ||
d2540875 | 323 | /* We must be in ONESHOT state here */ |
472c4a94 | 324 | WARN_ONCE(!clockevent_state_oneshot(dev), "Current state: %d\n", |
051ebd10 | 325 | clockevent_get_state(dev)); |
d2540875 | 326 | |
65516f8a MS |
327 | /* Shortcut for clockevent devices that can deal with ktime. */ |
328 | if (dev->features & CLOCK_EVT_FEAT_KTIME) | |
329 | return dev->set_next_ktime(expires, dev); | |
330 | ||
d1748302 MS |
331 | delta = ktime_to_ns(ktime_sub(expires, ktime_get())); |
332 | if (delta <= 0) | |
333 | return force ? clockevents_program_min_delta(dev) : -ETIME; | |
d316c57f | 334 | |
d1748302 MS |
335 | delta = min(delta, (int64_t) dev->max_delta_ns); |
336 | delta = max(delta, (int64_t) dev->min_delta_ns); | |
d316c57f | 337 | |
d1748302 MS |
338 | clc = ((unsigned long long) delta * dev->mult) >> dev->shift; |
339 | rc = dev->set_next_event((unsigned long) clc, dev); | |
340 | ||
341 | return (rc && force) ? clockevents_program_min_delta(dev) : rc; | |
d316c57f TG |
342 | } |
343 | ||
d316c57f | 344 | /* |
3eb05676 | 345 | * Called after a notify add to make devices available which were |
d316c57f TG |
346 | * released from the notifier call. |
347 | */ | |
348 | static void clockevents_notify_released(void) | |
349 | { | |
350 | struct clock_event_device *dev; | |
351 | ||
352 | while (!list_empty(&clockevents_released)) { | |
353 | dev = list_entry(clockevents_released.next, | |
354 | struct clock_event_device, list); | |
355 | list_del(&dev->list); | |
356 | list_add(&dev->list, &clockevent_devices); | |
7172a286 | 357 | tick_check_new_device(dev); |
d316c57f TG |
358 | } |
359 | } | |
360 | ||
03e13cf5 TG |
361 | /* |
362 | * Try to install a replacement clock event device | |
363 | */ | |
364 | static int clockevents_replace(struct clock_event_device *ced) | |
365 | { | |
366 | struct clock_event_device *dev, *newdev = NULL; | |
367 | ||
368 | list_for_each_entry(dev, &clockevent_devices, list) { | |
472c4a94 | 369 | if (dev == ced || !clockevent_state_detached(dev)) |
03e13cf5 TG |
370 | continue; |
371 | ||
372 | if (!tick_check_replacement(newdev, dev)) | |
373 | continue; | |
374 | ||
375 | if (!try_module_get(dev->owner)) | |
376 | continue; | |
377 | ||
378 | if (newdev) | |
379 | module_put(newdev->owner); | |
380 | newdev = dev; | |
381 | } | |
382 | if (newdev) { | |
383 | tick_install_replacement(newdev); | |
384 | list_del_init(&ced->list); | |
385 | } | |
386 | return newdev ? 0 : -EBUSY; | |
387 | } | |
388 | ||
389 | /* | |
390 | * Called with clockevents_mutex and clockevents_lock held | |
391 | */ | |
392 | static int __clockevents_try_unbind(struct clock_event_device *ced, int cpu) | |
393 | { | |
394 | /* Fast track. Device is unused */ | |
472c4a94 | 395 | if (clockevent_state_detached(ced)) { |
03e13cf5 TG |
396 | list_del_init(&ced->list); |
397 | return 0; | |
398 | } | |
399 | ||
400 | return ced == per_cpu(tick_cpu_device, cpu).evtdev ? -EAGAIN : -EBUSY; | |
401 | } | |
402 | ||
403 | /* | |
404 | * SMP function call to unbind a device | |
405 | */ | |
406 | static void __clockevents_unbind(void *arg) | |
407 | { | |
408 | struct ce_unbind *cu = arg; | |
409 | int res; | |
410 | ||
411 | raw_spin_lock(&clockevents_lock); | |
412 | res = __clockevents_try_unbind(cu->ce, smp_processor_id()); | |
413 | if (res == -EAGAIN) | |
414 | res = clockevents_replace(cu->ce); | |
415 | cu->res = res; | |
416 | raw_spin_unlock(&clockevents_lock); | |
417 | } | |
418 | ||
419 | /* | |
420 | * Issues smp function call to unbind a per cpu device. Called with | |
421 | * clockevents_mutex held. | |
422 | */ | |
423 | static int clockevents_unbind(struct clock_event_device *ced, int cpu) | |
424 | { | |
425 | struct ce_unbind cu = { .ce = ced, .res = -ENODEV }; | |
426 | ||
427 | smp_call_function_single(cpu, __clockevents_unbind, &cu, 1); | |
428 | return cu.res; | |
429 | } | |
430 | ||
431 | /* | |
432 | * Unbind a clockevents device. | |
433 | */ | |
434 | int clockevents_unbind_device(struct clock_event_device *ced, int cpu) | |
435 | { | |
436 | int ret; | |
437 | ||
438 | mutex_lock(&clockevents_mutex); | |
439 | ret = clockevents_unbind(ced, cpu); | |
440 | mutex_unlock(&clockevents_mutex); | |
441 | return ret; | |
442 | } | |
32a15832 | 443 | EXPORT_SYMBOL_GPL(clockevents_unbind_device); |
03e13cf5 | 444 | |
d316c57f TG |
445 | /** |
446 | * clockevents_register_device - register a clock event device | |
447 | * @dev: device to register | |
448 | */ | |
449 | void clockevents_register_device(struct clock_event_device *dev) | |
450 | { | |
f833bab8 SS |
451 | unsigned long flags; |
452 | ||
77e32c89 | 453 | /* Initialize state to DETACHED */ |
051ebd10 | 454 | clockevent_set_state(dev, CLOCK_EVT_STATE_DETACHED); |
77e32c89 | 455 | |
1b054b67 TG |
456 | if (!dev->cpumask) { |
457 | WARN_ON(num_possible_cpus() > 1); | |
458 | dev->cpumask = cpumask_of(smp_processor_id()); | |
459 | } | |
320ab2b0 | 460 | |
b5f91da0 | 461 | raw_spin_lock_irqsave(&clockevents_lock, flags); |
d316c57f TG |
462 | |
463 | list_add(&dev->list, &clockevent_devices); | |
7172a286 | 464 | tick_check_new_device(dev); |
d316c57f TG |
465 | clockevents_notify_released(); |
466 | ||
b5f91da0 | 467 | raw_spin_unlock_irqrestore(&clockevents_lock, flags); |
d316c57f | 468 | } |
c81fc2c3 | 469 | EXPORT_SYMBOL_GPL(clockevents_register_device); |
d316c57f | 470 | |
e5400321 | 471 | void clockevents_config(struct clock_event_device *dev, u32 freq) |
57f0fcbe | 472 | { |
c0e299b1 | 473 | u64 sec; |
57f0fcbe TG |
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); | |
97b94106 TG |
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); | |
57f0fcbe TG |
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 | */ | |
504 | void 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 | } | |
c35ef95c | 513 | EXPORT_SYMBOL_GPL(clockevents_config_and_register); |
57f0fcbe | 514 | |
627ee794 TG |
515 | int __clockevents_update_freq(struct clock_event_device *dev, u32 freq) |
516 | { | |
517 | clockevents_config(dev, freq); | |
518 | ||
472c4a94 | 519 | if (clockevent_state_oneshot(dev)) |
fe79a9ba SB |
520 | return clockevents_program_event(dev, dev->next_event, false); |
521 | ||
472c4a94 | 522 | if (clockevent_state_periodic(dev)) |
d7eb231c | 523 | return __clockevents_switch_state(dev, CLOCK_EVT_STATE_PERIODIC); |
627ee794 | 524 | |
fe79a9ba | 525 | return 0; |
627ee794 TG |
526 | } |
527 | ||
80b816b7 TG |
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 | |
627ee794 TG |
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. | |
80b816b7 TG |
539 | */ |
540 | int clockevents_update_freq(struct clock_event_device *dev, u32 freq) | |
541 | { | |
627ee794 TG |
542 | unsigned long flags; |
543 | int ret; | |
80b816b7 | 544 | |
627ee794 TG |
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; | |
80b816b7 TG |
551 | } |
552 | ||
d316c57f TG |
553 | /* |
554 | * Noop handler when we shut down an event device | |
555 | */ | |
7c1e7689 | 556 | void clockevents_handle_noop(struct clock_event_device *dev) |
d316c57f TG |
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 | * | |
db6f672e TG |
565 | * Called from various tick functions with clockevents_lock held and |
566 | * interrupts disabled. | |
d316c57f TG |
567 | */ |
568 | void clockevents_exchange_device(struct clock_event_device *old, | |
569 | struct clock_event_device *new) | |
570 | { | |
d316c57f TG |
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) { | |
ccf33d68 | 576 | module_put(old->owner); |
d7eb231c | 577 | clockevents_switch_state(old, CLOCK_EVT_STATE_DETACHED); |
d316c57f TG |
578 | list_del(&old->list); |
579 | list_add(&old->list, &clockevents_released); | |
580 | } | |
581 | ||
582 | if (new) { | |
472c4a94 | 583 | BUG_ON(!clockevent_state_detached(new)); |
2344abbc | 584 | clockevents_shutdown(new); |
d316c57f | 585 | } |
d316c57f TG |
586 | } |
587 | ||
adc78e6b RW |
588 | /** |
589 | * clockevents_suspend - suspend clock devices | |
590 | */ | |
591 | void clockevents_suspend(void) | |
592 | { | |
593 | struct clock_event_device *dev; | |
594 | ||
595 | list_for_each_entry_reverse(dev, &clockevent_devices, list) | |
a9d20988 | 596 | if (dev->suspend && !clockevent_state_detached(dev)) |
adc78e6b RW |
597 | dev->suspend(dev); |
598 | } | |
599 | ||
600 | /** | |
601 | * clockevents_resume - resume clock devices | |
602 | */ | |
603 | void clockevents_resume(void) | |
604 | { | |
605 | struct clock_event_device *dev; | |
606 | ||
607 | list_for_each_entry(dev, &clockevent_devices, list) | |
a9d20988 | 608 | if (dev->resume && !clockevent_state_detached(dev)) |
adc78e6b RW |
609 | dev->resume(dev); |
610 | } | |
611 | ||
a49b116d | 612 | #ifdef CONFIG_HOTPLUG_CPU |
d316c57f | 613 | /** |
a49b116d | 614 | * tick_cleanup_dead_cpu - Cleanup the tick and clockevents of a dead cpu |
d316c57f | 615 | */ |
a49b116d | 616 | void tick_cleanup_dead_cpu(int cpu) |
d316c57f | 617 | { |
bb6eddf7 | 618 | struct clock_event_device *dev, *tmp; |
f833bab8 | 619 | unsigned long flags; |
0b858e6f | 620 | |
b5f91da0 | 621 | raw_spin_lock_irqsave(&clockevents_lock, flags); |
d316c57f | 622 | |
a49b116d TG |
623 | tick_shutdown_broadcast_oneshot(cpu); |
624 | tick_shutdown_broadcast(cpu); | |
625 | tick_shutdown(cpu); | |
626 | /* | |
627 | * Unregister the clock event devices which were | |
628 | * released from the users in the notify chain. | |
629 | */ | |
630 | list_for_each_entry_safe(dev, tmp, &clockevents_released, list) | |
631 | list_del(&dev->list); | |
632 | /* | |
633 | * Now check whether the CPU has left unused per cpu devices | |
634 | */ | |
635 | list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) { | |
636 | if (cpumask_test_cpu(cpu, dev->cpumask) && | |
637 | cpumask_weight(dev->cpumask) == 1 && | |
638 | !tick_is_broadcast_device(dev)) { | |
472c4a94 | 639 | BUG_ON(!clockevent_state_detached(dev)); |
bb6eddf7 | 640 | list_del(&dev->list); |
bb6eddf7 | 641 | } |
d316c57f | 642 | } |
b5f91da0 | 643 | raw_spin_unlock_irqrestore(&clockevents_lock, flags); |
d316c57f | 644 | } |
a49b116d | 645 | #endif |
501f8670 TG |
646 | |
647 | #ifdef CONFIG_SYSFS | |
648 | struct bus_type clockevents_subsys = { | |
649 | .name = "clockevents", | |
650 | .dev_name = "clockevent", | |
651 | }; | |
652 | ||
653 | static DEFINE_PER_CPU(struct device, tick_percpu_dev); | |
654 | static struct tick_device *tick_get_tick_dev(struct device *dev); | |
655 | ||
656 | static ssize_t sysfs_show_current_tick_dev(struct device *dev, | |
657 | struct device_attribute *attr, | |
658 | char *buf) | |
659 | { | |
660 | struct tick_device *td; | |
661 | ssize_t count = 0; | |
662 | ||
663 | raw_spin_lock_irq(&clockevents_lock); | |
664 | td = tick_get_tick_dev(dev); | |
665 | if (td && td->evtdev) | |
666 | count = snprintf(buf, PAGE_SIZE, "%s\n", td->evtdev->name); | |
667 | raw_spin_unlock_irq(&clockevents_lock); | |
668 | return count; | |
669 | } | |
670 | static DEVICE_ATTR(current_device, 0444, sysfs_show_current_tick_dev, NULL); | |
671 | ||
03e13cf5 TG |
672 | /* We don't support the abomination of removable broadcast devices */ |
673 | static ssize_t sysfs_unbind_tick_dev(struct device *dev, | |
674 | struct device_attribute *attr, | |
675 | const char *buf, size_t count) | |
676 | { | |
677 | char name[CS_NAME_LEN]; | |
891292a7 | 678 | ssize_t ret = sysfs_get_uname(buf, name, count); |
03e13cf5 TG |
679 | struct clock_event_device *ce; |
680 | ||
681 | if (ret < 0) | |
682 | return ret; | |
683 | ||
684 | ret = -ENODEV; | |
685 | mutex_lock(&clockevents_mutex); | |
686 | raw_spin_lock_irq(&clockevents_lock); | |
687 | list_for_each_entry(ce, &clockevent_devices, list) { | |
688 | if (!strcmp(ce->name, name)) { | |
689 | ret = __clockevents_try_unbind(ce, dev->id); | |
690 | break; | |
691 | } | |
692 | } | |
693 | raw_spin_unlock_irq(&clockevents_lock); | |
694 | /* | |
695 | * We hold clockevents_mutex, so ce can't go away | |
696 | */ | |
697 | if (ret == -EAGAIN) | |
698 | ret = clockevents_unbind(ce, dev->id); | |
699 | mutex_unlock(&clockevents_mutex); | |
700 | return ret ? ret : count; | |
701 | } | |
702 | static DEVICE_ATTR(unbind_device, 0200, NULL, sysfs_unbind_tick_dev); | |
703 | ||
501f8670 TG |
704 | #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST |
705 | static struct device tick_bc_dev = { | |
706 | .init_name = "broadcast", | |
707 | .id = 0, | |
708 | .bus = &clockevents_subsys, | |
709 | }; | |
710 | ||
711 | static struct tick_device *tick_get_tick_dev(struct device *dev) | |
712 | { | |
713 | return dev == &tick_bc_dev ? tick_get_broadcast_device() : | |
714 | &per_cpu(tick_cpu_device, dev->id); | |
715 | } | |
716 | ||
717 | static __init int tick_broadcast_init_sysfs(void) | |
718 | { | |
719 | int err = device_register(&tick_bc_dev); | |
720 | ||
721 | if (!err) | |
722 | err = device_create_file(&tick_bc_dev, &dev_attr_current_device); | |
723 | return err; | |
724 | } | |
725 | #else | |
726 | static struct tick_device *tick_get_tick_dev(struct device *dev) | |
727 | { | |
728 | return &per_cpu(tick_cpu_device, dev->id); | |
729 | } | |
730 | static inline int tick_broadcast_init_sysfs(void) { return 0; } | |
de68d9b1 | 731 | #endif |
501f8670 TG |
732 | |
733 | static int __init tick_init_sysfs(void) | |
734 | { | |
735 | int cpu; | |
736 | ||
737 | for_each_possible_cpu(cpu) { | |
738 | struct device *dev = &per_cpu(tick_percpu_dev, cpu); | |
739 | int err; | |
740 | ||
741 | dev->id = cpu; | |
742 | dev->bus = &clockevents_subsys; | |
743 | err = device_register(dev); | |
744 | if (!err) | |
745 | err = device_create_file(dev, &dev_attr_current_device); | |
03e13cf5 TG |
746 | if (!err) |
747 | err = device_create_file(dev, &dev_attr_unbind_device); | |
501f8670 TG |
748 | if (err) |
749 | return err; | |
750 | } | |
751 | return tick_broadcast_init_sysfs(); | |
752 | } | |
753 | ||
754 | static int __init clockevents_init_sysfs(void) | |
755 | { | |
756 | int err = subsys_system_register(&clockevents_subsys, NULL); | |
757 | ||
758 | if (!err) | |
759 | err = tick_init_sysfs(); | |
760 | return err; | |
761 | } | |
762 | device_initcall(clockevents_init_sysfs); | |
763 | #endif /* SYSFS */ |