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 | |
77e32c89 VK |
97 | static int __clockevents_set_state(struct clock_event_device *dev, |
98 | enum clock_event_state state) | |
bd624d75 VK |
99 | { |
100 | /* Transition with legacy set_mode() callback */ | |
101 | if (dev->set_mode) { | |
102 | /* Legacy callback doesn't support new modes */ | |
77e32c89 | 103 | if (state > CLOCK_EVT_STATE_ONESHOT) |
bd624d75 | 104 | return -ENOSYS; |
77e32c89 VK |
105 | /* |
106 | * 'clock_event_state' and 'clock_event_mode' have 1-to-1 | |
107 | * mapping until *_ONESHOT, and so a simple cast will work. | |
108 | */ | |
109 | dev->set_mode((enum clock_event_mode)state, dev); | |
110 | dev->mode = (enum clock_event_mode)state; | |
bd624d75 VK |
111 | return 0; |
112 | } | |
113 | ||
114 | if (dev->features & CLOCK_EVT_FEAT_DUMMY) | |
115 | return 0; | |
116 | ||
77e32c89 VK |
117 | /* Transition with new state-specific callbacks */ |
118 | switch (state) { | |
119 | case CLOCK_EVT_STATE_DETACHED: | |
149aabcc | 120 | /* The clockevent device is getting replaced. Shut it down. */ |
bd624d75 | 121 | |
77e32c89 VK |
122 | case CLOCK_EVT_STATE_SHUTDOWN: |
123 | return dev->set_state_shutdown(dev); | |
bd624d75 | 124 | |
77e32c89 | 125 | case CLOCK_EVT_STATE_PERIODIC: |
bd624d75 VK |
126 | /* Core internal bug */ |
127 | if (!(dev->features & CLOCK_EVT_FEAT_PERIODIC)) | |
128 | return -ENOSYS; | |
77e32c89 | 129 | return dev->set_state_periodic(dev); |
bd624d75 | 130 | |
77e32c89 | 131 | case CLOCK_EVT_STATE_ONESHOT: |
bd624d75 VK |
132 | /* Core internal bug */ |
133 | if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT)) | |
134 | return -ENOSYS; | |
77e32c89 | 135 | return dev->set_state_oneshot(dev); |
bd624d75 | 136 | |
bd624d75 VK |
137 | default: |
138 | return -ENOSYS; | |
139 | } | |
140 | } | |
141 | ||
d316c57f | 142 | /** |
77e32c89 | 143 | * clockevents_set_state - set the operating state of a clock event device |
d316c57f | 144 | * @dev: device to modify |
77e32c89 | 145 | * @state: new state |
d316c57f TG |
146 | * |
147 | * Must be called with interrupts disabled ! | |
148 | */ | |
77e32c89 VK |
149 | void clockevents_set_state(struct clock_event_device *dev, |
150 | enum clock_event_state state) | |
d316c57f | 151 | { |
77e32c89 VK |
152 | if (dev->state != state) { |
153 | if (__clockevents_set_state(dev, state)) | |
bd624d75 VK |
154 | return; |
155 | ||
77e32c89 | 156 | dev->state = state; |
2d68259d MD |
157 | |
158 | /* | |
159 | * A nsec2cyc multiplicator of 0 is invalid and we'd crash | |
160 | * on it, so fix it up and emit a warning: | |
161 | */ | |
77e32c89 | 162 | if (state == CLOCK_EVT_STATE_ONESHOT) { |
2d68259d MD |
163 | if (unlikely(!dev->mult)) { |
164 | dev->mult = 1; | |
165 | WARN_ON(1); | |
166 | } | |
167 | } | |
d316c57f TG |
168 | } |
169 | } | |
170 | ||
2344abbc TG |
171 | /** |
172 | * clockevents_shutdown - shutdown the device and clear next_event | |
173 | * @dev: device to shutdown | |
174 | */ | |
175 | void clockevents_shutdown(struct clock_event_device *dev) | |
176 | { | |
77e32c89 | 177 | clockevents_set_state(dev, CLOCK_EVT_STATE_SHUTDOWN); |
2344abbc TG |
178 | dev->next_event.tv64 = KTIME_MAX; |
179 | } | |
180 | ||
554ef387 VK |
181 | /** |
182 | * clockevents_tick_resume - Resume the tick device before using it again | |
183 | * @dev: device to resume | |
184 | */ | |
185 | int clockevents_tick_resume(struct clock_event_device *dev) | |
186 | { | |
187 | int ret = 0; | |
188 | ||
77e32c89 | 189 | if (dev->set_mode) { |
554ef387 | 190 | dev->set_mode(CLOCK_EVT_MODE_RESUME, dev); |
554ef387 | 191 | dev->mode = CLOCK_EVT_MODE_RESUME; |
77e32c89 VK |
192 | } else if (dev->tick_resume) { |
193 | ret = dev->tick_resume(dev); | |
194 | } | |
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 | ||
77e32c89 | 251 | if (dev->state == CLOCK_EVT_STATE_SHUTDOWN) |
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 | ||
77e32c89 | 288 | if (dev->state == CLOCK_EVT_STATE_SHUTDOWN) |
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 | ||
77e32c89 | 320 | if (dev->state == CLOCK_EVT_STATE_SHUTDOWN) |
d316c57f TG |
321 | return 0; |
322 | ||
65516f8a MS |
323 | /* Shortcut for clockevent devices that can deal with ktime. */ |
324 | if (dev->features & CLOCK_EVT_FEAT_KTIME) | |
325 | return dev->set_next_ktime(expires, dev); | |
326 | ||
d1748302 MS |
327 | delta = ktime_to_ns(ktime_sub(expires, ktime_get())); |
328 | if (delta <= 0) | |
329 | return force ? clockevents_program_min_delta(dev) : -ETIME; | |
d316c57f | 330 | |
d1748302 MS |
331 | delta = min(delta, (int64_t) dev->max_delta_ns); |
332 | delta = max(delta, (int64_t) dev->min_delta_ns); | |
d316c57f | 333 | |
d1748302 MS |
334 | clc = ((unsigned long long) delta * dev->mult) >> dev->shift; |
335 | rc = dev->set_next_event((unsigned long) clc, dev); | |
336 | ||
337 | return (rc && force) ? clockevents_program_min_delta(dev) : rc; | |
d316c57f TG |
338 | } |
339 | ||
d316c57f | 340 | /* |
3eb05676 | 341 | * Called after a notify add to make devices available which were |
d316c57f TG |
342 | * released from the notifier call. |
343 | */ | |
344 | static void clockevents_notify_released(void) | |
345 | { | |
346 | struct clock_event_device *dev; | |
347 | ||
348 | while (!list_empty(&clockevents_released)) { | |
349 | dev = list_entry(clockevents_released.next, | |
350 | struct clock_event_device, list); | |
351 | list_del(&dev->list); | |
352 | list_add(&dev->list, &clockevent_devices); | |
7172a286 | 353 | tick_check_new_device(dev); |
d316c57f TG |
354 | } |
355 | } | |
356 | ||
03e13cf5 TG |
357 | /* |
358 | * Try to install a replacement clock event device | |
359 | */ | |
360 | static int clockevents_replace(struct clock_event_device *ced) | |
361 | { | |
362 | struct clock_event_device *dev, *newdev = NULL; | |
363 | ||
364 | list_for_each_entry(dev, &clockevent_devices, list) { | |
77e32c89 | 365 | if (dev == ced || dev->state != CLOCK_EVT_STATE_DETACHED) |
03e13cf5 TG |
366 | continue; |
367 | ||
368 | if (!tick_check_replacement(newdev, dev)) | |
369 | continue; | |
370 | ||
371 | if (!try_module_get(dev->owner)) | |
372 | continue; | |
373 | ||
374 | if (newdev) | |
375 | module_put(newdev->owner); | |
376 | newdev = dev; | |
377 | } | |
378 | if (newdev) { | |
379 | tick_install_replacement(newdev); | |
380 | list_del_init(&ced->list); | |
381 | } | |
382 | return newdev ? 0 : -EBUSY; | |
383 | } | |
384 | ||
385 | /* | |
386 | * Called with clockevents_mutex and clockevents_lock held | |
387 | */ | |
388 | static int __clockevents_try_unbind(struct clock_event_device *ced, int cpu) | |
389 | { | |
390 | /* Fast track. Device is unused */ | |
77e32c89 | 391 | if (ced->state == CLOCK_EVT_STATE_DETACHED) { |
03e13cf5 TG |
392 | list_del_init(&ced->list); |
393 | return 0; | |
394 | } | |
395 | ||
396 | return ced == per_cpu(tick_cpu_device, cpu).evtdev ? -EAGAIN : -EBUSY; | |
397 | } | |
398 | ||
399 | /* | |
400 | * SMP function call to unbind a device | |
401 | */ | |
402 | static void __clockevents_unbind(void *arg) | |
403 | { | |
404 | struct ce_unbind *cu = arg; | |
405 | int res; | |
406 | ||
407 | raw_spin_lock(&clockevents_lock); | |
408 | res = __clockevents_try_unbind(cu->ce, smp_processor_id()); | |
409 | if (res == -EAGAIN) | |
410 | res = clockevents_replace(cu->ce); | |
411 | cu->res = res; | |
412 | raw_spin_unlock(&clockevents_lock); | |
413 | } | |
414 | ||
415 | /* | |
416 | * Issues smp function call to unbind a per cpu device. Called with | |
417 | * clockevents_mutex held. | |
418 | */ | |
419 | static int clockevents_unbind(struct clock_event_device *ced, int cpu) | |
420 | { | |
421 | struct ce_unbind cu = { .ce = ced, .res = -ENODEV }; | |
422 | ||
423 | smp_call_function_single(cpu, __clockevents_unbind, &cu, 1); | |
424 | return cu.res; | |
425 | } | |
426 | ||
427 | /* | |
428 | * Unbind a clockevents device. | |
429 | */ | |
430 | int clockevents_unbind_device(struct clock_event_device *ced, int cpu) | |
431 | { | |
432 | int ret; | |
433 | ||
434 | mutex_lock(&clockevents_mutex); | |
435 | ret = clockevents_unbind(ced, cpu); | |
436 | mutex_unlock(&clockevents_mutex); | |
437 | return ret; | |
438 | } | |
32a15832 | 439 | EXPORT_SYMBOL_GPL(clockevents_unbind_device); |
03e13cf5 | 440 | |
77e32c89 | 441 | /* Sanity check of state transition callbacks */ |
bd624d75 VK |
442 | static int clockevents_sanity_check(struct clock_event_device *dev) |
443 | { | |
444 | /* Legacy set_mode() callback */ | |
445 | if (dev->set_mode) { | |
446 | /* We shouldn't be supporting new modes now */ | |
77e32c89 VK |
447 | WARN_ON(dev->set_state_periodic || dev->set_state_oneshot || |
448 | dev->set_state_shutdown || dev->tick_resume); | |
de81e64b VK |
449 | |
450 | BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED); | |
bd624d75 VK |
451 | return 0; |
452 | } | |
453 | ||
454 | if (dev->features & CLOCK_EVT_FEAT_DUMMY) | |
455 | return 0; | |
456 | ||
77e32c89 VK |
457 | /* New state-specific callbacks */ |
458 | if (!dev->set_state_shutdown) | |
bd624d75 VK |
459 | return -EINVAL; |
460 | ||
461 | if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) && | |
77e32c89 | 462 | !dev->set_state_periodic) |
bd624d75 VK |
463 | return -EINVAL; |
464 | ||
465 | if ((dev->features & CLOCK_EVT_FEAT_ONESHOT) && | |
77e32c89 | 466 | !dev->set_state_oneshot) |
bd624d75 VK |
467 | return -EINVAL; |
468 | ||
469 | return 0; | |
470 | } | |
471 | ||
d316c57f TG |
472 | /** |
473 | * clockevents_register_device - register a clock event device | |
474 | * @dev: device to register | |
475 | */ | |
476 | void clockevents_register_device(struct clock_event_device *dev) | |
477 | { | |
f833bab8 SS |
478 | unsigned long flags; |
479 | ||
bd624d75 VK |
480 | BUG_ON(clockevents_sanity_check(dev)); |
481 | ||
77e32c89 VK |
482 | /* Initialize state to DETACHED */ |
483 | dev->state = CLOCK_EVT_STATE_DETACHED; | |
484 | ||
1b054b67 TG |
485 | if (!dev->cpumask) { |
486 | WARN_ON(num_possible_cpus() > 1); | |
487 | dev->cpumask = cpumask_of(smp_processor_id()); | |
488 | } | |
320ab2b0 | 489 | |
b5f91da0 | 490 | raw_spin_lock_irqsave(&clockevents_lock, flags); |
d316c57f TG |
491 | |
492 | list_add(&dev->list, &clockevent_devices); | |
7172a286 | 493 | tick_check_new_device(dev); |
d316c57f TG |
494 | clockevents_notify_released(); |
495 | ||
b5f91da0 | 496 | raw_spin_unlock_irqrestore(&clockevents_lock, flags); |
d316c57f | 497 | } |
c81fc2c3 | 498 | EXPORT_SYMBOL_GPL(clockevents_register_device); |
d316c57f | 499 | |
e5400321 | 500 | void clockevents_config(struct clock_event_device *dev, u32 freq) |
57f0fcbe | 501 | { |
c0e299b1 | 502 | u64 sec; |
57f0fcbe TG |
503 | |
504 | if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT)) | |
505 | return; | |
506 | ||
507 | /* | |
508 | * Calculate the maximum number of seconds we can sleep. Limit | |
509 | * to 10 minutes for hardware which can program more than | |
510 | * 32bit ticks so we still get reasonable conversion values. | |
511 | */ | |
512 | sec = dev->max_delta_ticks; | |
513 | do_div(sec, freq); | |
514 | if (!sec) | |
515 | sec = 1; | |
516 | else if (sec > 600 && dev->max_delta_ticks > UINT_MAX) | |
517 | sec = 600; | |
518 | ||
519 | clockevents_calc_mult_shift(dev, freq, sec); | |
97b94106 TG |
520 | dev->min_delta_ns = cev_delta2ns(dev->min_delta_ticks, dev, false); |
521 | dev->max_delta_ns = cev_delta2ns(dev->max_delta_ticks, dev, true); | |
57f0fcbe TG |
522 | } |
523 | ||
524 | /** | |
525 | * clockevents_config_and_register - Configure and register a clock event device | |
526 | * @dev: device to register | |
527 | * @freq: The clock frequency | |
528 | * @min_delta: The minimum clock ticks to program in oneshot mode | |
529 | * @max_delta: The maximum clock ticks to program in oneshot mode | |
530 | * | |
531 | * min/max_delta can be 0 for devices which do not support oneshot mode. | |
532 | */ | |
533 | void clockevents_config_and_register(struct clock_event_device *dev, | |
534 | u32 freq, unsigned long min_delta, | |
535 | unsigned long max_delta) | |
536 | { | |
537 | dev->min_delta_ticks = min_delta; | |
538 | dev->max_delta_ticks = max_delta; | |
539 | clockevents_config(dev, freq); | |
540 | clockevents_register_device(dev); | |
541 | } | |
c35ef95c | 542 | EXPORT_SYMBOL_GPL(clockevents_config_and_register); |
57f0fcbe | 543 | |
627ee794 TG |
544 | int __clockevents_update_freq(struct clock_event_device *dev, u32 freq) |
545 | { | |
546 | clockevents_config(dev, freq); | |
547 | ||
77e32c89 | 548 | if (dev->state == CLOCK_EVT_STATE_ONESHOT) |
fe79a9ba SB |
549 | return clockevents_program_event(dev, dev->next_event, false); |
550 | ||
77e32c89 VK |
551 | if (dev->state == CLOCK_EVT_STATE_PERIODIC) |
552 | return __clockevents_set_state(dev, CLOCK_EVT_STATE_PERIODIC); | |
627ee794 | 553 | |
fe79a9ba | 554 | return 0; |
627ee794 TG |
555 | } |
556 | ||
80b816b7 TG |
557 | /** |
558 | * clockevents_update_freq - Update frequency and reprogram a clock event device. | |
559 | * @dev: device to modify | |
560 | * @freq: new device frequency | |
561 | * | |
562 | * Reconfigure and reprogram a clock event device in oneshot | |
563 | * mode. Must be called on the cpu for which the device delivers per | |
627ee794 TG |
564 | * cpu timer events. If called for the broadcast device the core takes |
565 | * care of serialization. | |
566 | * | |
567 | * Returns 0 on success, -ETIME when the event is in the past. | |
80b816b7 TG |
568 | */ |
569 | int clockevents_update_freq(struct clock_event_device *dev, u32 freq) | |
570 | { | |
627ee794 TG |
571 | unsigned long flags; |
572 | int ret; | |
80b816b7 | 573 | |
627ee794 TG |
574 | local_irq_save(flags); |
575 | ret = tick_broadcast_update_freq(dev, freq); | |
576 | if (ret == -ENODEV) | |
577 | ret = __clockevents_update_freq(dev, freq); | |
578 | local_irq_restore(flags); | |
579 | return ret; | |
80b816b7 TG |
580 | } |
581 | ||
d316c57f TG |
582 | /* |
583 | * Noop handler when we shut down an event device | |
584 | */ | |
7c1e7689 | 585 | void clockevents_handle_noop(struct clock_event_device *dev) |
d316c57f TG |
586 | { |
587 | } | |
588 | ||
589 | /** | |
590 | * clockevents_exchange_device - release and request clock devices | |
591 | * @old: device to release (can be NULL) | |
592 | * @new: device to request (can be NULL) | |
593 | * | |
db6f672e TG |
594 | * Called from various tick functions with clockevents_lock held and |
595 | * interrupts disabled. | |
d316c57f TG |
596 | */ |
597 | void clockevents_exchange_device(struct clock_event_device *old, | |
598 | struct clock_event_device *new) | |
599 | { | |
d316c57f TG |
600 | /* |
601 | * Caller releases a clock event device. We queue it into the | |
602 | * released list and do a notify add later. | |
603 | */ | |
604 | if (old) { | |
ccf33d68 | 605 | module_put(old->owner); |
77e32c89 | 606 | clockevents_set_state(old, CLOCK_EVT_STATE_DETACHED); |
d316c57f TG |
607 | list_del(&old->list); |
608 | list_add(&old->list, &clockevents_released); | |
609 | } | |
610 | ||
611 | if (new) { | |
77e32c89 | 612 | BUG_ON(new->state != CLOCK_EVT_STATE_DETACHED); |
2344abbc | 613 | clockevents_shutdown(new); |
d316c57f | 614 | } |
d316c57f TG |
615 | } |
616 | ||
adc78e6b RW |
617 | /** |
618 | * clockevents_suspend - suspend clock devices | |
619 | */ | |
620 | void clockevents_suspend(void) | |
621 | { | |
622 | struct clock_event_device *dev; | |
623 | ||
624 | list_for_each_entry_reverse(dev, &clockevent_devices, list) | |
625 | if (dev->suspend) | |
626 | dev->suspend(dev); | |
627 | } | |
628 | ||
629 | /** | |
630 | * clockevents_resume - resume clock devices | |
631 | */ | |
632 | void clockevents_resume(void) | |
633 | { | |
634 | struct clock_event_device *dev; | |
635 | ||
636 | list_for_each_entry(dev, &clockevent_devices, list) | |
637 | if (dev->resume) | |
638 | dev->resume(dev); | |
639 | } | |
640 | ||
a49b116d | 641 | #ifdef CONFIG_HOTPLUG_CPU |
d316c57f | 642 | /** |
a49b116d | 643 | * tick_cleanup_dead_cpu - Cleanup the tick and clockevents of a dead cpu |
d316c57f | 644 | */ |
a49b116d | 645 | void tick_cleanup_dead_cpu(int cpu) |
d316c57f | 646 | { |
bb6eddf7 | 647 | struct clock_event_device *dev, *tmp; |
f833bab8 | 648 | unsigned long flags; |
0b858e6f | 649 | |
b5f91da0 | 650 | raw_spin_lock_irqsave(&clockevents_lock, flags); |
d316c57f | 651 | |
a49b116d TG |
652 | tick_shutdown_broadcast_oneshot(cpu); |
653 | tick_shutdown_broadcast(cpu); | |
654 | tick_shutdown(cpu); | |
655 | /* | |
656 | * Unregister the clock event devices which were | |
657 | * released from the users in the notify chain. | |
658 | */ | |
659 | list_for_each_entry_safe(dev, tmp, &clockevents_released, list) | |
660 | list_del(&dev->list); | |
661 | /* | |
662 | * Now check whether the CPU has left unused per cpu devices | |
663 | */ | |
664 | list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) { | |
665 | if (cpumask_test_cpu(cpu, dev->cpumask) && | |
666 | cpumask_weight(dev->cpumask) == 1 && | |
667 | !tick_is_broadcast_device(dev)) { | |
668 | BUG_ON(dev->state != CLOCK_EVT_STATE_DETACHED); | |
bb6eddf7 | 669 | list_del(&dev->list); |
bb6eddf7 | 670 | } |
d316c57f | 671 | } |
b5f91da0 | 672 | raw_spin_unlock_irqrestore(&clockevents_lock, flags); |
d316c57f | 673 | } |
a49b116d | 674 | #endif |
501f8670 TG |
675 | |
676 | #ifdef CONFIG_SYSFS | |
677 | struct bus_type clockevents_subsys = { | |
678 | .name = "clockevents", | |
679 | .dev_name = "clockevent", | |
680 | }; | |
681 | ||
682 | static DEFINE_PER_CPU(struct device, tick_percpu_dev); | |
683 | static struct tick_device *tick_get_tick_dev(struct device *dev); | |
684 | ||
685 | static ssize_t sysfs_show_current_tick_dev(struct device *dev, | |
686 | struct device_attribute *attr, | |
687 | char *buf) | |
688 | { | |
689 | struct tick_device *td; | |
690 | ssize_t count = 0; | |
691 | ||
692 | raw_spin_lock_irq(&clockevents_lock); | |
693 | td = tick_get_tick_dev(dev); | |
694 | if (td && td->evtdev) | |
695 | count = snprintf(buf, PAGE_SIZE, "%s\n", td->evtdev->name); | |
696 | raw_spin_unlock_irq(&clockevents_lock); | |
697 | return count; | |
698 | } | |
699 | static DEVICE_ATTR(current_device, 0444, sysfs_show_current_tick_dev, NULL); | |
700 | ||
03e13cf5 TG |
701 | /* We don't support the abomination of removable broadcast devices */ |
702 | static ssize_t sysfs_unbind_tick_dev(struct device *dev, | |
703 | struct device_attribute *attr, | |
704 | const char *buf, size_t count) | |
705 | { | |
706 | char name[CS_NAME_LEN]; | |
891292a7 | 707 | ssize_t ret = sysfs_get_uname(buf, name, count); |
03e13cf5 TG |
708 | struct clock_event_device *ce; |
709 | ||
710 | if (ret < 0) | |
711 | return ret; | |
712 | ||
713 | ret = -ENODEV; | |
714 | mutex_lock(&clockevents_mutex); | |
715 | raw_spin_lock_irq(&clockevents_lock); | |
716 | list_for_each_entry(ce, &clockevent_devices, list) { | |
717 | if (!strcmp(ce->name, name)) { | |
718 | ret = __clockevents_try_unbind(ce, dev->id); | |
719 | break; | |
720 | } | |
721 | } | |
722 | raw_spin_unlock_irq(&clockevents_lock); | |
723 | /* | |
724 | * We hold clockevents_mutex, so ce can't go away | |
725 | */ | |
726 | if (ret == -EAGAIN) | |
727 | ret = clockevents_unbind(ce, dev->id); | |
728 | mutex_unlock(&clockevents_mutex); | |
729 | return ret ? ret : count; | |
730 | } | |
731 | static DEVICE_ATTR(unbind_device, 0200, NULL, sysfs_unbind_tick_dev); | |
732 | ||
501f8670 TG |
733 | #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST |
734 | static struct device tick_bc_dev = { | |
735 | .init_name = "broadcast", | |
736 | .id = 0, | |
737 | .bus = &clockevents_subsys, | |
738 | }; | |
739 | ||
740 | static struct tick_device *tick_get_tick_dev(struct device *dev) | |
741 | { | |
742 | return dev == &tick_bc_dev ? tick_get_broadcast_device() : | |
743 | &per_cpu(tick_cpu_device, dev->id); | |
744 | } | |
745 | ||
746 | static __init int tick_broadcast_init_sysfs(void) | |
747 | { | |
748 | int err = device_register(&tick_bc_dev); | |
749 | ||
750 | if (!err) | |
751 | err = device_create_file(&tick_bc_dev, &dev_attr_current_device); | |
752 | return err; | |
753 | } | |
754 | #else | |
755 | static struct tick_device *tick_get_tick_dev(struct device *dev) | |
756 | { | |
757 | return &per_cpu(tick_cpu_device, dev->id); | |
758 | } | |
759 | static inline int tick_broadcast_init_sysfs(void) { return 0; } | |
de68d9b1 | 760 | #endif |
501f8670 TG |
761 | |
762 | static int __init tick_init_sysfs(void) | |
763 | { | |
764 | int cpu; | |
765 | ||
766 | for_each_possible_cpu(cpu) { | |
767 | struct device *dev = &per_cpu(tick_percpu_dev, cpu); | |
768 | int err; | |
769 | ||
770 | dev->id = cpu; | |
771 | dev->bus = &clockevents_subsys; | |
772 | err = device_register(dev); | |
773 | if (!err) | |
774 | err = device_create_file(dev, &dev_attr_current_device); | |
03e13cf5 TG |
775 | if (!err) |
776 | err = device_create_file(dev, &dev_attr_unbind_device); | |
501f8670 TG |
777 | if (err) |
778 | return err; | |
779 | } | |
780 | return tick_broadcast_init_sysfs(); | |
781 | } | |
782 | ||
783 | static int __init clockevents_init_sysfs(void) | |
784 | { | |
785 | int err = subsys_system_register(&clockevents_subsys, NULL); | |
786 | ||
787 | if (!err) | |
788 | err = tick_init_sysfs(); | |
789 | return err; | |
790 | } | |
791 | device_initcall(clockevents_init_sysfs); | |
792 | #endif /* SYSFS */ |