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35728b82 | 1 | // SPDX-License-Identifier: GPL-2.0 |
d316c57f | 2 | /* |
d316c57f TG |
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 | |
d316c57f TG |
8 | */ |
9 | ||
10 | #include <linux/clockchips.h> | |
11 | #include <linux/hrtimer.h> | |
12 | #include <linux/init.h> | |
13 | #include <linux/module.h> | |
d316c57f | 14 | #include <linux/smp.h> |
501f8670 | 15 | #include <linux/device.h> |
d316c57f | 16 | |
8e1a928a HS |
17 | #include "tick-internal.h" |
18 | ||
d316c57f TG |
19 | /* The registered clock event devices */ |
20 | static LIST_HEAD(clockevent_devices); | |
21 | static LIST_HEAD(clockevents_released); | |
d316c57f | 22 | /* Protection for the above */ |
b5f91da0 | 23 | static DEFINE_RAW_SPINLOCK(clockevents_lock); |
03e13cf5 TG |
24 | /* Protection for unbind operations */ |
25 | static DEFINE_MUTEX(clockevents_mutex); | |
26 | ||
27 | struct ce_unbind { | |
28 | struct clock_event_device *ce; | |
29 | int res; | |
30 | }; | |
d316c57f | 31 | |
97b94106 TG |
32 | static u64 cev_delta2ns(unsigned long latch, struct clock_event_device *evt, |
33 | bool ismax) | |
d316c57f | 34 | { |
97813f2f | 35 | u64 clc = (u64) latch << evt->shift; |
97b94106 | 36 | u64 rnd; |
d316c57f | 37 | |
7d9df98b | 38 | if (WARN_ON(!evt->mult)) |
45fe4fe1 | 39 | evt->mult = 1; |
97b94106 TG |
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) && | |
10632008 | 69 | (!ismax || evt->mult <= (1ULL << evt->shift))) |
97b94106 | 70 | clc += rnd; |
45fe4fe1 | 71 | |
d316c57f | 72 | do_div(clc, evt->mult); |
d316c57f | 73 | |
97b94106 TG |
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 | */ | |
85 | u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt) | |
86 | { | |
87 | return cev_delta2ns(latch, evt, false); | |
d316c57f | 88 | } |
c81fc2c3 | 89 | EXPORT_SYMBOL_GPL(clockevent_delta2ns); |
d316c57f | 90 | |
d7eb231c TG |
91 | static int __clockevents_switch_state(struct clock_event_device *dev, |
92 | enum clock_event_state state) | |
bd624d75 | 93 | { |
bd624d75 VK |
94 | if (dev->features & CLOCK_EVT_FEAT_DUMMY) |
95 | return 0; | |
96 | ||
77e32c89 VK |
97 | /* Transition with new state-specific callbacks */ |
98 | switch (state) { | |
99 | case CLOCK_EVT_STATE_DETACHED: | |
149aabcc | 100 | /* The clockevent device is getting replaced. Shut it down. */ |
bd624d75 | 101 | |
77e32c89 | 102 | case CLOCK_EVT_STATE_SHUTDOWN: |
7c4a976c VK |
103 | if (dev->set_state_shutdown) |
104 | return dev->set_state_shutdown(dev); | |
105 | return 0; | |
bd624d75 | 106 | |
77e32c89 | 107 | case CLOCK_EVT_STATE_PERIODIC: |
bd624d75 VK |
108 | /* Core internal bug */ |
109 | if (!(dev->features & CLOCK_EVT_FEAT_PERIODIC)) | |
110 | return -ENOSYS; | |
7c4a976c VK |
111 | if (dev->set_state_periodic) |
112 | return dev->set_state_periodic(dev); | |
113 | return 0; | |
bd624d75 | 114 | |
77e32c89 | 115 | case CLOCK_EVT_STATE_ONESHOT: |
bd624d75 VK |
116 | /* Core internal bug */ |
117 | if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT)) | |
118 | return -ENOSYS; | |
7c4a976c VK |
119 | if (dev->set_state_oneshot) |
120 | return dev->set_state_oneshot(dev); | |
121 | return 0; | |
bd624d75 | 122 | |
8fff52fd VK |
123 | case CLOCK_EVT_STATE_ONESHOT_STOPPED: |
124 | /* Core internal bug */ | |
472c4a94 | 125 | if (WARN_ONCE(!clockevent_state_oneshot(dev), |
051ebd10 TG |
126 | "Current state: %d\n", |
127 | clockevent_get_state(dev))) | |
8fff52fd VK |
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 | ||
bd624d75 VK |
135 | default: |
136 | return -ENOSYS; | |
137 | } | |
138 | } | |
139 | ||
d316c57f | 140 | /** |
d7eb231c | 141 | * clockevents_switch_state - set the operating state of a clock event device |
d316c57f | 142 | * @dev: device to modify |
77e32c89 | 143 | * @state: new state |
d316c57f TG |
144 | * |
145 | * Must be called with interrupts disabled ! | |
146 | */ | |
d7eb231c TG |
147 | void clockevents_switch_state(struct clock_event_device *dev, |
148 | enum clock_event_state state) | |
d316c57f | 149 | { |
051ebd10 | 150 | if (clockevent_get_state(dev) != state) { |
d7eb231c | 151 | if (__clockevents_switch_state(dev, state)) |
bd624d75 VK |
152 | return; |
153 | ||
051ebd10 | 154 | clockevent_set_state(dev, state); |
2d68259d MD |
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 | */ | |
472c4a94 | 160 | if (clockevent_state_oneshot(dev)) { |
7d9df98b | 161 | if (WARN_ON(!dev->mult)) |
2d68259d | 162 | dev->mult = 1; |
2d68259d | 163 | } |
d316c57f TG |
164 | } |
165 | } | |
166 | ||
2344abbc TG |
167 | /** |
168 | * clockevents_shutdown - shutdown the device and clear next_event | |
169 | * @dev: device to shutdown | |
170 | */ | |
171 | void clockevents_shutdown(struct clock_event_device *dev) | |
172 | { | |
d7eb231c | 173 | clockevents_switch_state(dev, CLOCK_EVT_STATE_SHUTDOWN); |
2456e855 | 174 | dev->next_event = KTIME_MAX; |
2344abbc TG |
175 | } |
176 | ||
554ef387 VK |
177 | /** |
178 | * clockevents_tick_resume - Resume the tick device before using it again | |
179 | * @dev: device to resume | |
180 | */ | |
181 | int clockevents_tick_resume(struct clock_event_device *dev) | |
182 | { | |
183 | int ret = 0; | |
184 | ||
eef7635a | 185 | if (dev->tick_resume) |
77e32c89 | 186 | ret = dev->tick_resume(dev); |
554ef387 VK |
187 | |
188 | return ret; | |
189 | } | |
190 | ||
d1748302 MS |
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 | */ | |
202 | static 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) { | |
504d5874 JK |
206 | printk_deferred(KERN_WARNING |
207 | "CE: Reprogramming failure. Giving up\n"); | |
2456e855 | 208 | dev->next_event = KTIME_MAX; |
d1748302 MS |
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 | ||
504d5874 JK |
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); | |
d1748302 MS |
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 | */ | |
233 | static 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 | ||
472c4a94 | 243 | if (clockevent_state_shutdown(dev)) |
d1748302 MS |
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 | */ | |
272 | static int clockevents_program_min_delta(struct clock_event_device *dev) | |
273 | { | |
274 | unsigned long long clc; | |
3a29ddb1 JH |
275 | int64_t delta = 0; |
276 | int i; | |
d1748302 | 277 | |
3a29ddb1 JH |
278 | for (i = 0; i < 10; i++) { |
279 | delta += dev->min_delta_ns; | |
280 | dev->next_event = ktime_add_ns(ktime_get(), delta); | |
d1748302 | 281 | |
3a29ddb1 JH |
282 | if (clockevent_state_shutdown(dev)) |
283 | return 0; | |
d1748302 | 284 | |
3a29ddb1 JH |
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; | |
d1748302 MS |
291 | } |
292 | ||
293 | #endif /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */ | |
294 | ||
d316c57f TG |
295 | /** |
296 | * clockevents_program_event - Reprogram the clock event device. | |
d1748302 | 297 | * @dev: device to program |
d316c57f | 298 | * @expires: absolute expiry time (monotonic clock) |
d1748302 | 299 | * @force: program minimum delay if expires can not be set |
d316c57f TG |
300 | * |
301 | * Returns 0 on success, -ETIME when the event is in the past. | |
302 | */ | |
303 | int clockevents_program_event(struct clock_event_device *dev, ktime_t expires, | |
d1748302 | 304 | bool force) |
d316c57f TG |
305 | { |
306 | unsigned long long clc; | |
307 | int64_t delta; | |
d1748302 | 308 | int rc; |
d316c57f | 309 | |
7d9df98b | 310 | if (WARN_ON_ONCE(expires < 0)) |
167b1de3 | 311 | return -ETIME; |
167b1de3 | 312 | |
d316c57f TG |
313 | dev->next_event = expires; |
314 | ||
472c4a94 | 315 | if (clockevent_state_shutdown(dev)) |
d316c57f TG |
316 | return 0; |
317 | ||
d2540875 | 318 | /* We must be in ONESHOT state here */ |
472c4a94 | 319 | WARN_ONCE(!clockevent_state_oneshot(dev), "Current state: %d\n", |
051ebd10 | 320 | clockevent_get_state(dev)); |
d2540875 | 321 | |
65516f8a MS |
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 | ||
d1748302 MS |
326 | delta = ktime_to_ns(ktime_sub(expires, ktime_get())); |
327 | if (delta <= 0) | |
328 | return force ? clockevents_program_min_delta(dev) : -ETIME; | |
d316c57f | 329 | |
d1748302 MS |
330 | delta = min(delta, (int64_t) dev->max_delta_ns); |
331 | delta = max(delta, (int64_t) dev->min_delta_ns); | |
d316c57f | 332 | |
d1748302 MS |
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; | |
d316c57f TG |
337 | } |
338 | ||
d316c57f | 339 | /* |
3eb05676 | 340 | * Called after a notify add to make devices available which were |
d316c57f TG |
341 | * released from the notifier call. |
342 | */ | |
343 | static 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); | |
7172a286 | 352 | tick_check_new_device(dev); |
d316c57f TG |
353 | } |
354 | } | |
355 | ||
03e13cf5 TG |
356 | /* |
357 | * Try to install a replacement clock event device | |
358 | */ | |
359 | static 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) { | |
472c4a94 | 364 | if (dev == ced || !clockevent_state_detached(dev)) |
03e13cf5 TG |
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 | */ | |
387 | static int __clockevents_try_unbind(struct clock_event_device *ced, int cpu) | |
388 | { | |
389 | /* Fast track. Device is unused */ | |
472c4a94 | 390 | if (clockevent_state_detached(ced)) { |
03e13cf5 TG |
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 | */ | |
401 | static 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 | */ | |
418 | static 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 | */ | |
429 | int 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 | } | |
32a15832 | 438 | EXPORT_SYMBOL_GPL(clockevents_unbind_device); |
03e13cf5 | 439 | |
d316c57f TG |
440 | /** |
441 | * clockevents_register_device - register a clock event device | |
442 | * @dev: device to register | |
443 | */ | |
444 | void clockevents_register_device(struct clock_event_device *dev) | |
445 | { | |
f833bab8 SS |
446 | unsigned long flags; |
447 | ||
77e32c89 | 448 | /* Initialize state to DETACHED */ |
051ebd10 | 449 | clockevent_set_state(dev, CLOCK_EVT_STATE_DETACHED); |
77e32c89 | 450 | |
1b054b67 TG |
451 | if (!dev->cpumask) { |
452 | WARN_ON(num_possible_cpus() > 1); | |
453 | dev->cpumask = cpumask_of(smp_processor_id()); | |
454 | } | |
320ab2b0 | 455 | |
fbfa9260 SH |
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 | ||
b5f91da0 | 462 | raw_spin_lock_irqsave(&clockevents_lock, flags); |
d316c57f TG |
463 | |
464 | list_add(&dev->list, &clockevent_devices); | |
7172a286 | 465 | tick_check_new_device(dev); |
d316c57f TG |
466 | clockevents_notify_released(); |
467 | ||
b5f91da0 | 468 | raw_spin_unlock_irqrestore(&clockevents_lock, flags); |
d316c57f | 469 | } |
c81fc2c3 | 470 | EXPORT_SYMBOL_GPL(clockevents_register_device); |
d316c57f | 471 | |
0695bd99 | 472 | static void clockevents_config(struct clock_event_device *dev, u32 freq) |
57f0fcbe | 473 | { |
c0e299b1 | 474 | u64 sec; |
57f0fcbe TG |
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); | |
97b94106 TG |
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); | |
57f0fcbe TG |
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 | */ | |
505 | void 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 | } | |
c35ef95c | 514 | EXPORT_SYMBOL_GPL(clockevents_config_and_register); |
57f0fcbe | 515 | |
627ee794 TG |
516 | int __clockevents_update_freq(struct clock_event_device *dev, u32 freq) |
517 | { | |
518 | clockevents_config(dev, freq); | |
519 | ||
472c4a94 | 520 | if (clockevent_state_oneshot(dev)) |
fe79a9ba SB |
521 | return clockevents_program_event(dev, dev->next_event, false); |
522 | ||
472c4a94 | 523 | if (clockevent_state_periodic(dev)) |
d7eb231c | 524 | return __clockevents_switch_state(dev, CLOCK_EVT_STATE_PERIODIC); |
627ee794 | 525 | |
fe79a9ba | 526 | return 0; |
627ee794 TG |
527 | } |
528 | ||
80b816b7 TG |
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 | |
627ee794 TG |
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. | |
80b816b7 TG |
540 | */ |
541 | int clockevents_update_freq(struct clock_event_device *dev, u32 freq) | |
542 | { | |
627ee794 TG |
543 | unsigned long flags; |
544 | int ret; | |
80b816b7 | 545 | |
627ee794 TG |
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; | |
80b816b7 TG |
552 | } |
553 | ||
d316c57f TG |
554 | /* |
555 | * Noop handler when we shut down an event device | |
556 | */ | |
7c1e7689 | 557 | void clockevents_handle_noop(struct clock_event_device *dev) |
d316c57f TG |
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 | * | |
db6f672e TG |
566 | * Called from various tick functions with clockevents_lock held and |
567 | * interrupts disabled. | |
d316c57f TG |
568 | */ |
569 | void clockevents_exchange_device(struct clock_event_device *old, | |
570 | struct clock_event_device *new) | |
571 | { | |
d316c57f TG |
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) { | |
ccf33d68 | 577 | module_put(old->owner); |
d7eb231c | 578 | clockevents_switch_state(old, CLOCK_EVT_STATE_DETACHED); |
d316c57f TG |
579 | list_del(&old->list); |
580 | list_add(&old->list, &clockevents_released); | |
581 | } | |
582 | ||
583 | if (new) { | |
472c4a94 | 584 | BUG_ON(!clockevent_state_detached(new)); |
2344abbc | 585 | clockevents_shutdown(new); |
d316c57f | 586 | } |
d316c57f TG |
587 | } |
588 | ||
adc78e6b RW |
589 | /** |
590 | * clockevents_suspend - suspend clock devices | |
591 | */ | |
592 | void clockevents_suspend(void) | |
593 | { | |
594 | struct clock_event_device *dev; | |
595 | ||
596 | list_for_each_entry_reverse(dev, &clockevent_devices, list) | |
a9d20988 | 597 | if (dev->suspend && !clockevent_state_detached(dev)) |
adc78e6b RW |
598 | dev->suspend(dev); |
599 | } | |
600 | ||
601 | /** | |
602 | * clockevents_resume - resume clock devices | |
603 | */ | |
604 | void clockevents_resume(void) | |
605 | { | |
606 | struct clock_event_device *dev; | |
607 | ||
608 | list_for_each_entry(dev, &clockevent_devices, list) | |
a9d20988 | 609 | if (dev->resume && !clockevent_state_detached(dev)) |
adc78e6b RW |
610 | dev->resume(dev); |
611 | } | |
612 | ||
a49b116d | 613 | #ifdef CONFIG_HOTPLUG_CPU |
1b72d432 TG |
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 | */ | |
622 | void 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 | ||
d316c57f | 630 | /** |
a49b116d | 631 | * tick_cleanup_dead_cpu - Cleanup the tick and clockevents of a dead cpu |
d316c57f | 632 | */ |
a49b116d | 633 | void tick_cleanup_dead_cpu(int cpu) |
d316c57f | 634 | { |
bb6eddf7 | 635 | struct clock_event_device *dev, *tmp; |
f833bab8 | 636 | unsigned long flags; |
0b858e6f | 637 | |
b5f91da0 | 638 | raw_spin_lock_irqsave(&clockevents_lock, flags); |
d316c57f | 639 | |
a49b116d TG |
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)) { | |
472c4a94 | 654 | BUG_ON(!clockevent_state_detached(dev)); |
bb6eddf7 | 655 | list_del(&dev->list); |
bb6eddf7 | 656 | } |
d316c57f | 657 | } |
b5f91da0 | 658 | raw_spin_unlock_irqrestore(&clockevents_lock, flags); |
d316c57f | 659 | } |
a49b116d | 660 | #endif |
501f8670 TG |
661 | |
662 | #ifdef CONFIG_SYSFS | |
775be506 | 663 | static struct bus_type clockevents_subsys = { |
501f8670 TG |
664 | .name = "clockevents", |
665 | .dev_name = "clockevent", | |
666 | }; | |
667 | ||
668 | static DEFINE_PER_CPU(struct device, tick_percpu_dev); | |
669 | static struct tick_device *tick_get_tick_dev(struct device *dev); | |
670 | ||
671 | static 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 | } | |
685 | static DEVICE_ATTR(current_device, 0444, sysfs_show_current_tick_dev, NULL); | |
686 | ||
03e13cf5 TG |
687 | /* We don't support the abomination of removable broadcast devices */ |
688 | static 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]; | |
891292a7 | 693 | ssize_t ret = sysfs_get_uname(buf, name, count); |
03e13cf5 TG |
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 | } | |
717 | static DEVICE_ATTR(unbind_device, 0200, NULL, sysfs_unbind_tick_dev); | |
718 | ||
501f8670 TG |
719 | #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST |
720 | static struct device tick_bc_dev = { | |
721 | .init_name = "broadcast", | |
722 | .id = 0, | |
723 | .bus = &clockevents_subsys, | |
724 | }; | |
725 | ||
726 | static 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 | ||
732 | static __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 | |
741 | static struct tick_device *tick_get_tick_dev(struct device *dev) | |
742 | { | |
743 | return &per_cpu(tick_cpu_device, dev->id); | |
744 | } | |
745 | static inline int tick_broadcast_init_sysfs(void) { return 0; } | |
de68d9b1 | 746 | #endif |
501f8670 TG |
747 | |
748 | static 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); | |
03e13cf5 TG |
761 | if (!err) |
762 | err = device_create_file(dev, &dev_attr_unbind_device); | |
501f8670 TG |
763 | if (err) |
764 | return err; | |
765 | } | |
766 | return tick_broadcast_init_sysfs(); | |
767 | } | |
768 | ||
769 | static 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 | } | |
777 | device_initcall(clockevents_init_sysfs); | |
778 | #endif /* SYSFS */ |