Commit | Line | Data |
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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> |
d316c57f | 19 | |
8e1a928a HS |
20 | #include "tick-internal.h" |
21 | ||
d316c57f TG |
22 | /* The registered clock event devices */ |
23 | static LIST_HEAD(clockevent_devices); | |
24 | static LIST_HEAD(clockevents_released); | |
d316c57f | 25 | /* Protection for the above */ |
b5f91da0 | 26 | static DEFINE_RAW_SPINLOCK(clockevents_lock); |
d316c57f TG |
27 | |
28 | /** | |
29 | * clockevents_delta2ns - Convert a latch value (device ticks) to nanoseconds | |
30 | * @latch: value to convert | |
31 | * @evt: pointer to clock event device descriptor | |
32 | * | |
33 | * Math helper, returns latch value converted to nanoseconds (bound checked) | |
34 | */ | |
97813f2f | 35 | u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt) |
d316c57f | 36 | { |
97813f2f | 37 | u64 clc = (u64) latch << evt->shift; |
d316c57f | 38 | |
45fe4fe1 IM |
39 | if (unlikely(!evt->mult)) { |
40 | evt->mult = 1; | |
41 | WARN_ON(1); | |
42 | } | |
43 | ||
d316c57f TG |
44 | do_div(clc, evt->mult); |
45 | if (clc < 1000) | |
46 | clc = 1000; | |
97813f2f JH |
47 | if (clc > KTIME_MAX) |
48 | clc = KTIME_MAX; | |
d316c57f | 49 | |
97813f2f | 50 | return clc; |
d316c57f | 51 | } |
c81fc2c3 | 52 | EXPORT_SYMBOL_GPL(clockevent_delta2ns); |
d316c57f TG |
53 | |
54 | /** | |
55 | * clockevents_set_mode - set the operating mode of a clock event device | |
56 | * @dev: device to modify | |
57 | * @mode: new mode | |
58 | * | |
59 | * Must be called with interrupts disabled ! | |
60 | */ | |
61 | void clockevents_set_mode(struct clock_event_device *dev, | |
62 | enum clock_event_mode mode) | |
63 | { | |
64 | if (dev->mode != mode) { | |
65 | dev->set_mode(mode, dev); | |
66 | dev->mode = mode; | |
2d68259d MD |
67 | |
68 | /* | |
69 | * A nsec2cyc multiplicator of 0 is invalid and we'd crash | |
70 | * on it, so fix it up and emit a warning: | |
71 | */ | |
72 | if (mode == CLOCK_EVT_MODE_ONESHOT) { | |
73 | if (unlikely(!dev->mult)) { | |
74 | dev->mult = 1; | |
75 | WARN_ON(1); | |
76 | } | |
77 | } | |
d316c57f TG |
78 | } |
79 | } | |
80 | ||
2344abbc TG |
81 | /** |
82 | * clockevents_shutdown - shutdown the device and clear next_event | |
83 | * @dev: device to shutdown | |
84 | */ | |
85 | void clockevents_shutdown(struct clock_event_device *dev) | |
86 | { | |
87 | clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN); | |
88 | dev->next_event.tv64 = KTIME_MAX; | |
89 | } | |
90 | ||
d1748302 MS |
91 | #ifdef CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST |
92 | ||
93 | /* Limit min_delta to a jiffie */ | |
94 | #define MIN_DELTA_LIMIT (NSEC_PER_SEC / HZ) | |
95 | ||
96 | /** | |
97 | * clockevents_increase_min_delta - raise minimum delta of a clock event device | |
98 | * @dev: device to increase the minimum delta | |
99 | * | |
100 | * Returns 0 on success, -ETIME when the minimum delta reached the limit. | |
101 | */ | |
102 | static int clockevents_increase_min_delta(struct clock_event_device *dev) | |
103 | { | |
104 | /* Nothing to do if we already reached the limit */ | |
105 | if (dev->min_delta_ns >= MIN_DELTA_LIMIT) { | |
106 | printk(KERN_WARNING "CE: Reprogramming failure. Giving up\n"); | |
107 | dev->next_event.tv64 = KTIME_MAX; | |
108 | return -ETIME; | |
109 | } | |
110 | ||
111 | if (dev->min_delta_ns < 5000) | |
112 | dev->min_delta_ns = 5000; | |
113 | else | |
114 | dev->min_delta_ns += dev->min_delta_ns >> 1; | |
115 | ||
116 | if (dev->min_delta_ns > MIN_DELTA_LIMIT) | |
117 | dev->min_delta_ns = MIN_DELTA_LIMIT; | |
118 | ||
119 | printk(KERN_WARNING "CE: %s increased min_delta_ns to %llu nsec\n", | |
120 | dev->name ? dev->name : "?", | |
121 | (unsigned long long) dev->min_delta_ns); | |
122 | return 0; | |
123 | } | |
124 | ||
125 | /** | |
126 | * clockevents_program_min_delta - Set clock event device to the minimum delay. | |
127 | * @dev: device to program | |
128 | * | |
129 | * Returns 0 on success, -ETIME when the retry loop failed. | |
130 | */ | |
131 | static int clockevents_program_min_delta(struct clock_event_device *dev) | |
132 | { | |
133 | unsigned long long clc; | |
134 | int64_t delta; | |
135 | int i; | |
136 | ||
137 | for (i = 0;;) { | |
138 | delta = dev->min_delta_ns; | |
139 | dev->next_event = ktime_add_ns(ktime_get(), delta); | |
140 | ||
141 | if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN) | |
142 | return 0; | |
143 | ||
144 | dev->retries++; | |
145 | clc = ((unsigned long long) delta * dev->mult) >> dev->shift; | |
146 | if (dev->set_next_event((unsigned long) clc, dev) == 0) | |
147 | return 0; | |
148 | ||
149 | if (++i > 2) { | |
150 | /* | |
151 | * We tried 3 times to program the device with the | |
152 | * given min_delta_ns. Try to increase the minimum | |
153 | * delta, if that fails as well get out of here. | |
154 | */ | |
155 | if (clockevents_increase_min_delta(dev)) | |
156 | return -ETIME; | |
157 | i = 0; | |
158 | } | |
159 | } | |
160 | } | |
161 | ||
162 | #else /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */ | |
163 | ||
164 | /** | |
165 | * clockevents_program_min_delta - Set clock event device to the minimum delay. | |
166 | * @dev: device to program | |
167 | * | |
168 | * Returns 0 on success, -ETIME when the retry loop failed. | |
169 | */ | |
170 | static int clockevents_program_min_delta(struct clock_event_device *dev) | |
171 | { | |
172 | unsigned long long clc; | |
173 | int64_t delta; | |
174 | ||
175 | delta = dev->min_delta_ns; | |
176 | dev->next_event = ktime_add_ns(ktime_get(), delta); | |
177 | ||
178 | if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN) | |
179 | return 0; | |
180 | ||
181 | dev->retries++; | |
182 | clc = ((unsigned long long) delta * dev->mult) >> dev->shift; | |
183 | return dev->set_next_event((unsigned long) clc, dev); | |
184 | } | |
185 | ||
186 | #endif /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */ | |
187 | ||
d316c57f TG |
188 | /** |
189 | * clockevents_program_event - Reprogram the clock event device. | |
d1748302 | 190 | * @dev: device to program |
d316c57f | 191 | * @expires: absolute expiry time (monotonic clock) |
d1748302 | 192 | * @force: program minimum delay if expires can not be set |
d316c57f TG |
193 | * |
194 | * Returns 0 on success, -ETIME when the event is in the past. | |
195 | */ | |
196 | int clockevents_program_event(struct clock_event_device *dev, ktime_t expires, | |
d1748302 | 197 | bool force) |
d316c57f TG |
198 | { |
199 | unsigned long long clc; | |
200 | int64_t delta; | |
d1748302 | 201 | int rc; |
d316c57f | 202 | |
167b1de3 TG |
203 | if (unlikely(expires.tv64 < 0)) { |
204 | WARN_ON_ONCE(1); | |
205 | return -ETIME; | |
206 | } | |
207 | ||
d316c57f TG |
208 | dev->next_event = expires; |
209 | ||
210 | if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN) | |
211 | return 0; | |
212 | ||
65516f8a MS |
213 | /* Shortcut for clockevent devices that can deal with ktime. */ |
214 | if (dev->features & CLOCK_EVT_FEAT_KTIME) | |
215 | return dev->set_next_ktime(expires, dev); | |
216 | ||
d1748302 MS |
217 | delta = ktime_to_ns(ktime_sub(expires, ktime_get())); |
218 | if (delta <= 0) | |
219 | return force ? clockevents_program_min_delta(dev) : -ETIME; | |
d316c57f | 220 | |
d1748302 MS |
221 | delta = min(delta, (int64_t) dev->max_delta_ns); |
222 | delta = max(delta, (int64_t) dev->min_delta_ns); | |
d316c57f | 223 | |
d1748302 MS |
224 | clc = ((unsigned long long) delta * dev->mult) >> dev->shift; |
225 | rc = dev->set_next_event((unsigned long) clc, dev); | |
226 | ||
227 | return (rc && force) ? clockevents_program_min_delta(dev) : rc; | |
d316c57f TG |
228 | } |
229 | ||
d316c57f | 230 | /* |
3eb05676 | 231 | * Called after a notify add to make devices available which were |
d316c57f TG |
232 | * released from the notifier call. |
233 | */ | |
234 | static void clockevents_notify_released(void) | |
235 | { | |
236 | struct clock_event_device *dev; | |
237 | ||
238 | while (!list_empty(&clockevents_released)) { | |
239 | dev = list_entry(clockevents_released.next, | |
240 | struct clock_event_device, list); | |
241 | list_del(&dev->list); | |
242 | list_add(&dev->list, &clockevent_devices); | |
7172a286 | 243 | tick_check_new_device(dev); |
d316c57f TG |
244 | } |
245 | } | |
246 | ||
247 | /** | |
248 | * clockevents_register_device - register a clock event device | |
249 | * @dev: device to register | |
250 | */ | |
251 | void clockevents_register_device(struct clock_event_device *dev) | |
252 | { | |
f833bab8 SS |
253 | unsigned long flags; |
254 | ||
d316c57f | 255 | BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED); |
1b054b67 TG |
256 | if (!dev->cpumask) { |
257 | WARN_ON(num_possible_cpus() > 1); | |
258 | dev->cpumask = cpumask_of(smp_processor_id()); | |
259 | } | |
320ab2b0 | 260 | |
b5f91da0 | 261 | raw_spin_lock_irqsave(&clockevents_lock, flags); |
d316c57f TG |
262 | |
263 | list_add(&dev->list, &clockevent_devices); | |
7172a286 | 264 | tick_check_new_device(dev); |
d316c57f TG |
265 | clockevents_notify_released(); |
266 | ||
b5f91da0 | 267 | raw_spin_unlock_irqrestore(&clockevents_lock, flags); |
d316c57f | 268 | } |
c81fc2c3 | 269 | EXPORT_SYMBOL_GPL(clockevents_register_device); |
d316c57f | 270 | |
e5400321 | 271 | void clockevents_config(struct clock_event_device *dev, u32 freq) |
57f0fcbe | 272 | { |
c0e299b1 | 273 | u64 sec; |
57f0fcbe TG |
274 | |
275 | if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT)) | |
276 | return; | |
277 | ||
278 | /* | |
279 | * Calculate the maximum number of seconds we can sleep. Limit | |
280 | * to 10 minutes for hardware which can program more than | |
281 | * 32bit ticks so we still get reasonable conversion values. | |
282 | */ | |
283 | sec = dev->max_delta_ticks; | |
284 | do_div(sec, freq); | |
285 | if (!sec) | |
286 | sec = 1; | |
287 | else if (sec > 600 && dev->max_delta_ticks > UINT_MAX) | |
288 | sec = 600; | |
289 | ||
290 | clockevents_calc_mult_shift(dev, freq, sec); | |
291 | dev->min_delta_ns = clockevent_delta2ns(dev->min_delta_ticks, dev); | |
292 | dev->max_delta_ns = clockevent_delta2ns(dev->max_delta_ticks, dev); | |
293 | } | |
294 | ||
295 | /** | |
296 | * clockevents_config_and_register - Configure and register a clock event device | |
297 | * @dev: device to register | |
298 | * @freq: The clock frequency | |
299 | * @min_delta: The minimum clock ticks to program in oneshot mode | |
300 | * @max_delta: The maximum clock ticks to program in oneshot mode | |
301 | * | |
302 | * min/max_delta can be 0 for devices which do not support oneshot mode. | |
303 | */ | |
304 | void clockevents_config_and_register(struct clock_event_device *dev, | |
305 | u32 freq, unsigned long min_delta, | |
306 | unsigned long max_delta) | |
307 | { | |
308 | dev->min_delta_ticks = min_delta; | |
309 | dev->max_delta_ticks = max_delta; | |
310 | clockevents_config(dev, freq); | |
311 | clockevents_register_device(dev); | |
312 | } | |
c35ef95c | 313 | EXPORT_SYMBOL_GPL(clockevents_config_and_register); |
57f0fcbe | 314 | |
80b816b7 TG |
315 | /** |
316 | * clockevents_update_freq - Update frequency and reprogram a clock event device. | |
317 | * @dev: device to modify | |
318 | * @freq: new device frequency | |
319 | * | |
320 | * Reconfigure and reprogram a clock event device in oneshot | |
321 | * mode. Must be called on the cpu for which the device delivers per | |
322 | * cpu timer events with interrupts disabled! Returns 0 on success, | |
323 | * -ETIME when the event is in the past. | |
324 | */ | |
325 | int clockevents_update_freq(struct clock_event_device *dev, u32 freq) | |
326 | { | |
327 | clockevents_config(dev, freq); | |
328 | ||
329 | if (dev->mode != CLOCK_EVT_MODE_ONESHOT) | |
330 | return 0; | |
331 | ||
d1748302 | 332 | return clockevents_program_event(dev, dev->next_event, false); |
80b816b7 TG |
333 | } |
334 | ||
d316c57f TG |
335 | /* |
336 | * Noop handler when we shut down an event device | |
337 | */ | |
7c1e7689 | 338 | void clockevents_handle_noop(struct clock_event_device *dev) |
d316c57f TG |
339 | { |
340 | } | |
341 | ||
342 | /** | |
343 | * clockevents_exchange_device - release and request clock devices | |
344 | * @old: device to release (can be NULL) | |
345 | * @new: device to request (can be NULL) | |
346 | * | |
347 | * Called from the notifier chain. clockevents_lock is held already | |
348 | */ | |
349 | void clockevents_exchange_device(struct clock_event_device *old, | |
350 | struct clock_event_device *new) | |
351 | { | |
352 | unsigned long flags; | |
353 | ||
354 | local_irq_save(flags); | |
355 | /* | |
356 | * Caller releases a clock event device. We queue it into the | |
357 | * released list and do a notify add later. | |
358 | */ | |
359 | if (old) { | |
d316c57f TG |
360 | clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED); |
361 | list_del(&old->list); | |
362 | list_add(&old->list, &clockevents_released); | |
363 | } | |
364 | ||
365 | if (new) { | |
366 | BUG_ON(new->mode != CLOCK_EVT_MODE_UNUSED); | |
2344abbc | 367 | clockevents_shutdown(new); |
d316c57f TG |
368 | } |
369 | local_irq_restore(flags); | |
370 | } | |
371 | ||
adc78e6b RW |
372 | /** |
373 | * clockevents_suspend - suspend clock devices | |
374 | */ | |
375 | void clockevents_suspend(void) | |
376 | { | |
377 | struct clock_event_device *dev; | |
378 | ||
379 | list_for_each_entry_reverse(dev, &clockevent_devices, list) | |
380 | if (dev->suspend) | |
381 | dev->suspend(dev); | |
382 | } | |
383 | ||
384 | /** | |
385 | * clockevents_resume - resume clock devices | |
386 | */ | |
387 | void clockevents_resume(void) | |
388 | { | |
389 | struct clock_event_device *dev; | |
390 | ||
391 | list_for_each_entry(dev, &clockevent_devices, list) | |
392 | if (dev->resume) | |
393 | dev->resume(dev); | |
394 | } | |
395 | ||
de68d9b1 | 396 | #ifdef CONFIG_GENERIC_CLOCKEVENTS |
d316c57f TG |
397 | /** |
398 | * clockevents_notify - notification about relevant events | |
399 | */ | |
400 | void clockevents_notify(unsigned long reason, void *arg) | |
401 | { | |
bb6eddf7 | 402 | struct clock_event_device *dev, *tmp; |
f833bab8 | 403 | unsigned long flags; |
bb6eddf7 | 404 | int cpu; |
0b858e6f | 405 | |
b5f91da0 | 406 | raw_spin_lock_irqsave(&clockevents_lock, flags); |
d316c57f TG |
407 | |
408 | switch (reason) { | |
8c53daf6 TG |
409 | case CLOCK_EVT_NOTIFY_BROADCAST_ON: |
410 | case CLOCK_EVT_NOTIFY_BROADCAST_OFF: | |
411 | case CLOCK_EVT_NOTIFY_BROADCAST_FORCE: | |
412 | tick_broadcast_on_off(reason, arg); | |
413 | break; | |
414 | ||
415 | case CLOCK_EVT_NOTIFY_BROADCAST_ENTER: | |
416 | case CLOCK_EVT_NOTIFY_BROADCAST_EXIT: | |
417 | tick_broadcast_oneshot_control(reason); | |
418 | break; | |
419 | ||
420 | case CLOCK_EVT_NOTIFY_CPU_DYING: | |
421 | tick_handover_do_timer(arg); | |
422 | break; | |
423 | ||
424 | case CLOCK_EVT_NOTIFY_SUSPEND: | |
425 | tick_suspend(); | |
426 | tick_suspend_broadcast(); | |
427 | break; | |
428 | ||
429 | case CLOCK_EVT_NOTIFY_RESUME: | |
430 | tick_resume(); | |
431 | break; | |
432 | ||
d316c57f | 433 | case CLOCK_EVT_NOTIFY_CPU_DEAD: |
8c53daf6 TG |
434 | tick_shutdown_broadcast_oneshot(arg); |
435 | tick_shutdown_broadcast(arg); | |
436 | tick_shutdown(arg); | |
d316c57f TG |
437 | /* |
438 | * Unregister the clock event devices which were | |
439 | * released from the users in the notify chain. | |
440 | */ | |
bb6eddf7 TG |
441 | list_for_each_entry_safe(dev, tmp, &clockevents_released, list) |
442 | list_del(&dev->list); | |
443 | /* | |
444 | * Now check whether the CPU has left unused per cpu devices | |
445 | */ | |
446 | cpu = *((int *)arg); | |
447 | list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) { | |
448 | if (cpumask_test_cpu(cpu, dev->cpumask) && | |
ea9d8e3f XF |
449 | cpumask_weight(dev->cpumask) == 1 && |
450 | !tick_is_broadcast_device(dev)) { | |
bb6eddf7 TG |
451 | BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED); |
452 | list_del(&dev->list); | |
453 | } | |
454 | } | |
d316c57f TG |
455 | break; |
456 | default: | |
457 | break; | |
458 | } | |
b5f91da0 | 459 | raw_spin_unlock_irqrestore(&clockevents_lock, flags); |
d316c57f TG |
460 | } |
461 | EXPORT_SYMBOL_GPL(clockevents_notify); | |
de68d9b1 | 462 | #endif |