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Commit | Line | Data |
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4f86d3a8 LB |
1 | /* |
2 | * cpuidle.c - core cpuidle infrastructure | |
3 | * | |
4 | * (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> | |
5 | * Shaohua Li <shaohua.li@intel.com> | |
6 | * Adam Belay <abelay@novell.com> | |
7 | * | |
8 | * This code is licenced under the GPL. | |
9 | */ | |
10 | ||
b60e6a0e | 11 | #include <linux/clockchips.h> |
4f86d3a8 LB |
12 | #include <linux/kernel.h> |
13 | #include <linux/mutex.h> | |
14 | #include <linux/sched.h> | |
15 | #include <linux/notifier.h> | |
e8db0be1 | 16 | #include <linux/pm_qos.h> |
4f86d3a8 LB |
17 | #include <linux/cpu.h> |
18 | #include <linux/cpuidle.h> | |
9a0b8415 | 19 | #include <linux/ktime.h> |
2e94d1f7 | 20 | #include <linux/hrtimer.h> |
884b17e1 | 21 | #include <linux/module.h> |
38106313 | 22 | #include <linux/suspend.h> |
124cf911 | 23 | #include <linux/tick.h> |
288f023e | 24 | #include <trace/events/power.h> |
4f86d3a8 LB |
25 | |
26 | #include "cpuidle.h" | |
27 | ||
28 | DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices); | |
4c637b21 | 29 | DEFINE_PER_CPU(struct cpuidle_device, cpuidle_dev); |
4f86d3a8 LB |
30 | |
31 | DEFINE_MUTEX(cpuidle_lock); | |
32 | LIST_HEAD(cpuidle_detected_devices); | |
4f86d3a8 LB |
33 | |
34 | static int enabled_devices; | |
62027aea | 35 | static int off __read_mostly; |
a0bfa137 | 36 | static int initialized __read_mostly; |
62027aea LB |
37 | |
38 | int cpuidle_disabled(void) | |
39 | { | |
40 | return off; | |
41 | } | |
d91ee586 LB |
42 | void disable_cpuidle(void) |
43 | { | |
44 | off = 1; | |
45 | } | |
4f86d3a8 | 46 | |
ef2b22ac RW |
47 | bool cpuidle_not_available(struct cpuidle_driver *drv, |
48 | struct cpuidle_device *dev) | |
31a34090 RW |
49 | { |
50 | return off || !initialized || !drv || !dev || !dev->enabled; | |
51 | } | |
52 | ||
1a022e3f BO |
53 | /** |
54 | * cpuidle_play_dead - cpu off-lining | |
55 | * | |
ee01e663 | 56 | * Returns in case of an error or no driver |
1a022e3f BO |
57 | */ |
58 | int cpuidle_play_dead(void) | |
59 | { | |
60 | struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); | |
bf4d1b5d | 61 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
8aef33a7 | 62 | int i; |
1a022e3f | 63 | |
ee01e663 TK |
64 | if (!drv) |
65 | return -ENODEV; | |
66 | ||
1a022e3f | 67 | /* Find lowest-power state that supports long-term idle */ |
7d51d979 | 68 | for (i = drv->state_count - 1; i >= 0; i--) |
8aef33a7 DL |
69 | if (drv->states[i].enter_dead) |
70 | return drv->states[i].enter_dead(dev, i); | |
1a022e3f BO |
71 | |
72 | return -ENODEV; | |
73 | } | |
74 | ||
ef2b22ac | 75 | static int find_deepest_state(struct cpuidle_driver *drv, |
0d94039f RW |
76 | struct cpuidle_device *dev, |
77 | unsigned int max_latency, | |
78 | unsigned int forbidden_flags, | |
79 | bool freeze) | |
a6220fc1 RW |
80 | { |
81 | unsigned int latency_req = 0; | |
7d51d979 | 82 | int i, ret = -ENXIO; |
a6220fc1 | 83 | |
7d51d979 | 84 | for (i = 0; i < drv->state_count; i++) { |
a6220fc1 RW |
85 | struct cpuidle_state *s = &drv->states[i]; |
86 | struct cpuidle_state_usage *su = &dev->states_usage[i]; | |
87 | ||
124cf911 | 88 | if (s->disabled || su->disable || s->exit_latency <= latency_req |
0d94039f RW |
89 | || s->exit_latency > max_latency |
90 | || (s->flags & forbidden_flags) | |
124cf911 | 91 | || (freeze && !s->enter_freeze)) |
a6220fc1 RW |
92 | continue; |
93 | ||
94 | latency_req = s->exit_latency; | |
95 | ret = i; | |
96 | } | |
97 | return ret; | |
98 | } | |
99 | ||
87e9b9f1 | 100 | #ifdef CONFIG_SUSPEND |
ef2b22ac RW |
101 | /** |
102 | * cpuidle_find_deepest_state - Find the deepest available idle state. | |
103 | * @drv: cpuidle driver for the given CPU. | |
104 | * @dev: cpuidle device for the given CPU. | |
105 | */ | |
106 | int cpuidle_find_deepest_state(struct cpuidle_driver *drv, | |
107 | struct cpuidle_device *dev) | |
108 | { | |
0d94039f | 109 | return find_deepest_state(drv, dev, UINT_MAX, 0, false); |
ef2b22ac RW |
110 | } |
111 | ||
124cf911 RW |
112 | static void enter_freeze_proper(struct cpuidle_driver *drv, |
113 | struct cpuidle_device *dev, int index) | |
114 | { | |
ae0afb4f RW |
115 | /* |
116 | * trace_suspend_resume() called by tick_freeze() for the last CPU | |
117 | * executing it contains RCU usage regarded as invalid in the idle | |
118 | * context, so tell RCU about that. | |
119 | */ | |
120 | RCU_NONIDLE(tick_freeze()); | |
124cf911 RW |
121 | /* |
122 | * The state used here cannot be a "coupled" one, because the "coupled" | |
123 | * cpuidle mechanism enables interrupts and doing that with timekeeping | |
124 | * suspended is generally unsafe. | |
125 | */ | |
126 | drv->states[index].enter_freeze(dev, drv, index); | |
127 | WARN_ON(!irqs_disabled()); | |
128 | /* | |
129 | * timekeeping_resume() that will be called by tick_unfreeze() for the | |
ae0afb4f | 130 | * first CPU executing it calls functions containing RCU read-side |
124cf911 RW |
131 | * critical sections, so tell RCU about that. |
132 | */ | |
133 | RCU_NONIDLE(tick_unfreeze()); | |
134 | } | |
135 | ||
38106313 RW |
136 | /** |
137 | * cpuidle_enter_freeze - Enter an idle state suitable for suspend-to-idle. | |
ef2b22ac RW |
138 | * @drv: cpuidle driver for the given CPU. |
139 | * @dev: cpuidle device for the given CPU. | |
38106313 | 140 | * |
124cf911 | 141 | * If there are states with the ->enter_freeze callback, find the deepest of |
ef2b22ac | 142 | * them and enter it with frozen tick. |
38106313 | 143 | */ |
ef2b22ac | 144 | int cpuidle_enter_freeze(struct cpuidle_driver *drv, struct cpuidle_device *dev) |
38106313 | 145 | { |
38106313 RW |
146 | int index; |
147 | ||
124cf911 RW |
148 | /* |
149 | * Find the deepest state with ->enter_freeze present, which guarantees | |
150 | * that interrupts won't be enabled when it exits and allows the tick to | |
151 | * be frozen safely. | |
152 | */ | |
0d94039f | 153 | index = find_deepest_state(drv, dev, UINT_MAX, 0, true); |
ef2b22ac | 154 | if (index >= 0) |
124cf911 | 155 | enter_freeze_proper(drv, dev, index); |
124cf911 | 156 | |
ef2b22ac | 157 | return index; |
38106313 | 158 | } |
87e9b9f1 | 159 | #endif /* CONFIG_SUSPEND */ |
38106313 | 160 | |
56cfbf74 CC |
161 | /** |
162 | * cpuidle_enter_state - enter the state and update stats | |
163 | * @dev: cpuidle device for this cpu | |
164 | * @drv: cpuidle driver for this cpu | |
7312280b | 165 | * @index: index into the states table in @drv of the state to enter |
56cfbf74 CC |
166 | */ |
167 | int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, | |
554c06ba | 168 | int index) |
56cfbf74 CC |
169 | { |
170 | int entered_state; | |
171 | ||
554c06ba | 172 | struct cpuidle_state *target_state = &drv->states[index]; |
df8d9eea | 173 | bool broadcast = !!(target_state->flags & CPUIDLE_FLAG_TIMER_STOP); |
554c06ba DL |
174 | ktime_t time_start, time_end; |
175 | s64 diff; | |
176 | ||
df8d9eea RW |
177 | /* |
178 | * Tell the time framework to switch to a broadcast timer because our | |
179 | * local timer will be shut down. If a local timer is used from another | |
180 | * CPU as a broadcast timer, this call may fail if it is not available. | |
181 | */ | |
827a5aef | 182 | if (broadcast && tick_broadcast_enter()) { |
0d94039f RW |
183 | index = find_deepest_state(drv, dev, target_state->exit_latency, |
184 | CPUIDLE_FLAG_TIMER_STOP, false); | |
185 | if (index < 0) { | |
186 | default_idle_call(); | |
187 | return -EBUSY; | |
188 | } | |
189 | target_state = &drv->states[index]; | |
827a5aef | 190 | } |
df8d9eea | 191 | |
faad3849 RW |
192 | /* Take note of the planned idle state. */ |
193 | sched_idle_set_state(target_state); | |
194 | ||
30fe6884 | 195 | trace_cpu_idle_rcuidle(index, dev->cpu); |
554c06ba DL |
196 | time_start = ktime_get(); |
197 | ||
198 | entered_state = target_state->enter(dev, drv, index); | |
199 | ||
200 | time_end = ktime_get(); | |
30fe6884 | 201 | trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu); |
554c06ba | 202 | |
faad3849 RW |
203 | /* The cpu is no longer idle or about to enter idle. */ |
204 | sched_idle_set_state(NULL); | |
205 | ||
df8d9eea RW |
206 | if (broadcast) { |
207 | if (WARN_ON_ONCE(!irqs_disabled())) | |
208 | local_irq_disable(); | |
209 | ||
210 | tick_broadcast_exit(); | |
211 | } | |
212 | ||
0b89e9aa PB |
213 | if (!cpuidle_state_is_coupled(dev, drv, entered_state)) |
214 | local_irq_enable(); | |
554c06ba DL |
215 | |
216 | diff = ktime_to_us(ktime_sub(time_end, time_start)); | |
217 | if (diff > INT_MAX) | |
218 | diff = INT_MAX; | |
219 | ||
220 | dev->last_residency = (int) diff; | |
56cfbf74 CC |
221 | |
222 | if (entered_state >= 0) { | |
223 | /* Update cpuidle counters */ | |
224 | /* This can be moved to within driver enter routine | |
225 | * but that results in multiple copies of same code. | |
226 | */ | |
a474a515 | 227 | dev->states_usage[entered_state].time += dev->last_residency; |
56cfbf74 CC |
228 | dev->states_usage[entered_state].usage++; |
229 | } else { | |
230 | dev->last_residency = 0; | |
231 | } | |
232 | ||
233 | return entered_state; | |
234 | } | |
235 | ||
4f86d3a8 | 236 | /** |
907e30f1 DL |
237 | * cpuidle_select - ask the cpuidle framework to choose an idle state |
238 | * | |
239 | * @drv: the cpuidle driver | |
240 | * @dev: the cpuidle device | |
4f86d3a8 | 241 | * |
907e30f1 | 242 | * Returns the index of the idle state. |
4f86d3a8 | 243 | */ |
907e30f1 | 244 | int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev) |
4f86d3a8 | 245 | { |
907e30f1 DL |
246 | return cpuidle_curr_governor->select(drv, dev); |
247 | } | |
ba8f20c2 | 248 | |
907e30f1 DL |
249 | /** |
250 | * cpuidle_enter - enter into the specified idle state | |
251 | * | |
252 | * @drv: the cpuidle driver tied with the cpu | |
253 | * @dev: the cpuidle device | |
254 | * @index: the index in the idle state table | |
255 | * | |
256 | * Returns the index in the idle state, < 0 in case of error. | |
257 | * The error code depends on the backend driver | |
258 | */ | |
259 | int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev, | |
260 | int index) | |
261 | { | |
262 | if (cpuidle_state_is_coupled(dev, drv, index)) | |
263 | return cpuidle_enter_state_coupled(dev, drv, index); | |
264 | return cpuidle_enter_state(dev, drv, index); | |
265 | } | |
b60e6a0e | 266 | |
907e30f1 DL |
267 | /** |
268 | * cpuidle_reflect - tell the underlying governor what was the state | |
269 | * we were in | |
270 | * | |
271 | * @dev : the cpuidle device | |
272 | * @index: the index in the idle state table | |
273 | * | |
274 | */ | |
275 | void cpuidle_reflect(struct cpuidle_device *dev, int index) | |
276 | { | |
a802ea96 | 277 | if (cpuidle_curr_governor->reflect && index >= 0) |
907e30f1 | 278 | cpuidle_curr_governor->reflect(dev, index); |
4f86d3a8 LB |
279 | } |
280 | ||
281 | /** | |
282 | * cpuidle_install_idle_handler - installs the cpuidle idle loop handler | |
283 | */ | |
284 | void cpuidle_install_idle_handler(void) | |
285 | { | |
a0bfa137 | 286 | if (enabled_devices) { |
4f86d3a8 LB |
287 | /* Make sure all changes finished before we switch to new idle */ |
288 | smp_wmb(); | |
a0bfa137 | 289 | initialized = 1; |
4f86d3a8 LB |
290 | } |
291 | } | |
292 | ||
293 | /** | |
294 | * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler | |
295 | */ | |
296 | void cpuidle_uninstall_idle_handler(void) | |
297 | { | |
a0bfa137 LB |
298 | if (enabled_devices) { |
299 | initialized = 0; | |
2ed903c5 | 300 | wake_up_all_idle_cpus(); |
4f86d3a8 | 301 | } |
442bf3aa DL |
302 | |
303 | /* | |
304 | * Make sure external observers (such as the scheduler) | |
305 | * are done looking at pointed idle states. | |
306 | */ | |
307 | synchronize_rcu(); | |
4f86d3a8 LB |
308 | } |
309 | ||
310 | /** | |
311 | * cpuidle_pause_and_lock - temporarily disables CPUIDLE | |
312 | */ | |
313 | void cpuidle_pause_and_lock(void) | |
314 | { | |
315 | mutex_lock(&cpuidle_lock); | |
316 | cpuidle_uninstall_idle_handler(); | |
317 | } | |
318 | ||
319 | EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock); | |
320 | ||
321 | /** | |
322 | * cpuidle_resume_and_unlock - resumes CPUIDLE operation | |
323 | */ | |
324 | void cpuidle_resume_and_unlock(void) | |
325 | { | |
326 | cpuidle_install_idle_handler(); | |
327 | mutex_unlock(&cpuidle_lock); | |
328 | } | |
329 | ||
330 | EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock); | |
331 | ||
8651f97b PM |
332 | /* Currently used in suspend/resume path to suspend cpuidle */ |
333 | void cpuidle_pause(void) | |
334 | { | |
335 | mutex_lock(&cpuidle_lock); | |
336 | cpuidle_uninstall_idle_handler(); | |
337 | mutex_unlock(&cpuidle_lock); | |
338 | } | |
339 | ||
340 | /* Currently used in suspend/resume path to resume cpuidle */ | |
341 | void cpuidle_resume(void) | |
342 | { | |
343 | mutex_lock(&cpuidle_lock); | |
344 | cpuidle_install_idle_handler(); | |
345 | mutex_unlock(&cpuidle_lock); | |
346 | } | |
347 | ||
4f86d3a8 LB |
348 | /** |
349 | * cpuidle_enable_device - enables idle PM for a CPU | |
350 | * @dev: the CPU | |
351 | * | |
352 | * This function must be called between cpuidle_pause_and_lock and | |
353 | * cpuidle_resume_and_unlock when used externally. | |
354 | */ | |
355 | int cpuidle_enable_device(struct cpuidle_device *dev) | |
356 | { | |
5df0aa73 | 357 | int ret; |
bf4d1b5d | 358 | struct cpuidle_driver *drv; |
4f86d3a8 | 359 | |
1b0a0e9a SB |
360 | if (!dev) |
361 | return -EINVAL; | |
362 | ||
4f86d3a8 LB |
363 | if (dev->enabled) |
364 | return 0; | |
bf4d1b5d DL |
365 | |
366 | drv = cpuidle_get_cpu_driver(dev); | |
367 | ||
e1689795 | 368 | if (!drv || !cpuidle_curr_governor) |
4f86d3a8 | 369 | return -EIO; |
bf4d1b5d | 370 | |
10b9d3f8 DL |
371 | if (!dev->registered) |
372 | return -EINVAL; | |
373 | ||
bf4d1b5d DL |
374 | ret = cpuidle_add_device_sysfs(dev); |
375 | if (ret) | |
4f86d3a8 LB |
376 | return ret; |
377 | ||
378 | if (cpuidle_curr_governor->enable && | |
e1689795 | 379 | (ret = cpuidle_curr_governor->enable(drv, dev))) |
4f86d3a8 LB |
380 | goto fail_sysfs; |
381 | ||
4f86d3a8 LB |
382 | smp_wmb(); |
383 | ||
384 | dev->enabled = 1; | |
385 | ||
386 | enabled_devices++; | |
387 | return 0; | |
388 | ||
389 | fail_sysfs: | |
bf4d1b5d | 390 | cpuidle_remove_device_sysfs(dev); |
4f86d3a8 LB |
391 | |
392 | return ret; | |
393 | } | |
394 | ||
395 | EXPORT_SYMBOL_GPL(cpuidle_enable_device); | |
396 | ||
397 | /** | |
398 | * cpuidle_disable_device - disables idle PM for a CPU | |
399 | * @dev: the CPU | |
400 | * | |
401 | * This function must be called between cpuidle_pause_and_lock and | |
402 | * cpuidle_resume_and_unlock when used externally. | |
403 | */ | |
404 | void cpuidle_disable_device(struct cpuidle_device *dev) | |
405 | { | |
bf4d1b5d DL |
406 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
407 | ||
cf31cd1a | 408 | if (!dev || !dev->enabled) |
4f86d3a8 | 409 | return; |
bf4d1b5d DL |
410 | |
411 | if (!drv || !cpuidle_curr_governor) | |
4f86d3a8 LB |
412 | return; |
413 | ||
414 | dev->enabled = 0; | |
415 | ||
416 | if (cpuidle_curr_governor->disable) | |
bf4d1b5d | 417 | cpuidle_curr_governor->disable(drv, dev); |
4f86d3a8 | 418 | |
bf4d1b5d | 419 | cpuidle_remove_device_sysfs(dev); |
4f86d3a8 LB |
420 | enabled_devices--; |
421 | } | |
422 | ||
423 | EXPORT_SYMBOL_GPL(cpuidle_disable_device); | |
424 | ||
f6bb51a5 DL |
425 | static void __cpuidle_unregister_device(struct cpuidle_device *dev) |
426 | { | |
427 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); | |
428 | ||
429 | list_del(&dev->device_list); | |
430 | per_cpu(cpuidle_devices, dev->cpu) = NULL; | |
431 | module_put(drv->owner); | |
432 | } | |
433 | ||
267d4bf8 | 434 | static void __cpuidle_device_init(struct cpuidle_device *dev) |
5df0aa73 DL |
435 | { |
436 | memset(dev->states_usage, 0, sizeof(dev->states_usage)); | |
437 | dev->last_residency = 0; | |
5df0aa73 DL |
438 | } |
439 | ||
4f86d3a8 | 440 | /** |
dcb84f33 VP |
441 | * __cpuidle_register_device - internal register function called before register |
442 | * and enable routines | |
4f86d3a8 | 443 | * @dev: the cpu |
dcb84f33 VP |
444 | * |
445 | * cpuidle_lock mutex must be held before this is called | |
4f86d3a8 | 446 | */ |
dcb84f33 | 447 | static int __cpuidle_register_device(struct cpuidle_device *dev) |
4f86d3a8 LB |
448 | { |
449 | int ret; | |
bf4d1b5d | 450 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
4f86d3a8 | 451 | |
bf4d1b5d | 452 | if (!try_module_get(drv->owner)) |
4f86d3a8 LB |
453 | return -EINVAL; |
454 | ||
4f86d3a8 LB |
455 | per_cpu(cpuidle_devices, dev->cpu) = dev; |
456 | list_add(&dev->device_list, &cpuidle_detected_devices); | |
4f86d3a8 | 457 | |
4126c019 | 458 | ret = cpuidle_coupled_register_device(dev); |
47182668 | 459 | if (ret) |
f6bb51a5 | 460 | __cpuidle_unregister_device(dev); |
47182668 VK |
461 | else |
462 | dev->registered = 1; | |
4f86d3a8 | 463 | |
47182668 | 464 | return ret; |
dcb84f33 VP |
465 | } |
466 | ||
467 | /** | |
468 | * cpuidle_register_device - registers a CPU's idle PM feature | |
469 | * @dev: the cpu | |
470 | */ | |
471 | int cpuidle_register_device(struct cpuidle_device *dev) | |
472 | { | |
c878a52d | 473 | int ret = -EBUSY; |
dcb84f33 | 474 | |
1b0a0e9a SB |
475 | if (!dev) |
476 | return -EINVAL; | |
477 | ||
dcb84f33 VP |
478 | mutex_lock(&cpuidle_lock); |
479 | ||
c878a52d DL |
480 | if (dev->registered) |
481 | goto out_unlock; | |
482 | ||
267d4bf8 | 483 | __cpuidle_device_init(dev); |
5df0aa73 | 484 | |
f6bb51a5 DL |
485 | ret = __cpuidle_register_device(dev); |
486 | if (ret) | |
487 | goto out_unlock; | |
488 | ||
489 | ret = cpuidle_add_sysfs(dev); | |
490 | if (ret) | |
491 | goto out_unregister; | |
dcb84f33 | 492 | |
10b9d3f8 | 493 | ret = cpuidle_enable_device(dev); |
f6bb51a5 DL |
494 | if (ret) |
495 | goto out_sysfs; | |
10b9d3f8 | 496 | |
4f86d3a8 LB |
497 | cpuidle_install_idle_handler(); |
498 | ||
f6bb51a5 | 499 | out_unlock: |
4f86d3a8 LB |
500 | mutex_unlock(&cpuidle_lock); |
501 | ||
f6bb51a5 DL |
502 | return ret; |
503 | ||
504 | out_sysfs: | |
505 | cpuidle_remove_sysfs(dev); | |
506 | out_unregister: | |
507 | __cpuidle_unregister_device(dev); | |
508 | goto out_unlock; | |
4f86d3a8 LB |
509 | } |
510 | ||
511 | EXPORT_SYMBOL_GPL(cpuidle_register_device); | |
512 | ||
513 | /** | |
514 | * cpuidle_unregister_device - unregisters a CPU's idle PM feature | |
515 | * @dev: the cpu | |
516 | */ | |
517 | void cpuidle_unregister_device(struct cpuidle_device *dev) | |
518 | { | |
813e8e3d | 519 | if (!dev || dev->registered == 0) |
dcb84f33 VP |
520 | return; |
521 | ||
4f86d3a8 LB |
522 | cpuidle_pause_and_lock(); |
523 | ||
524 | cpuidle_disable_device(dev); | |
525 | ||
1aef40e2 | 526 | cpuidle_remove_sysfs(dev); |
f6bb51a5 DL |
527 | |
528 | __cpuidle_unregister_device(dev); | |
4f86d3a8 | 529 | |
4126c019 CC |
530 | cpuidle_coupled_unregister_device(dev); |
531 | ||
4f86d3a8 | 532 | cpuidle_resume_and_unlock(); |
4f86d3a8 LB |
533 | } |
534 | ||
535 | EXPORT_SYMBOL_GPL(cpuidle_unregister_device); | |
536 | ||
1c192d04 | 537 | /** |
4c637b21 DL |
538 | * cpuidle_unregister: unregister a driver and the devices. This function |
539 | * can be used only if the driver has been previously registered through | |
540 | * the cpuidle_register function. | |
541 | * | |
542 | * @drv: a valid pointer to a struct cpuidle_driver | |
543 | */ | |
544 | void cpuidle_unregister(struct cpuidle_driver *drv) | |
545 | { | |
546 | int cpu; | |
547 | struct cpuidle_device *device; | |
548 | ||
82467a5a | 549 | for_each_cpu(cpu, drv->cpumask) { |
4c637b21 DL |
550 | device = &per_cpu(cpuidle_dev, cpu); |
551 | cpuidle_unregister_device(device); | |
552 | } | |
553 | ||
554 | cpuidle_unregister_driver(drv); | |
555 | } | |
556 | EXPORT_SYMBOL_GPL(cpuidle_unregister); | |
557 | ||
558 | /** | |
559 | * cpuidle_register: registers the driver and the cpu devices with the | |
560 | * coupled_cpus passed as parameter. This function is used for all common | |
561 | * initialization pattern there are in the arch specific drivers. The | |
562 | * devices is globally defined in this file. | |
563 | * | |
564 | * @drv : a valid pointer to a struct cpuidle_driver | |
565 | * @coupled_cpus: a cpumask for the coupled states | |
566 | * | |
567 | * Returns 0 on success, < 0 otherwise | |
568 | */ | |
569 | int cpuidle_register(struct cpuidle_driver *drv, | |
570 | const struct cpumask *const coupled_cpus) | |
571 | { | |
572 | int ret, cpu; | |
573 | struct cpuidle_device *device; | |
574 | ||
575 | ret = cpuidle_register_driver(drv); | |
576 | if (ret) { | |
577 | pr_err("failed to register cpuidle driver\n"); | |
578 | return ret; | |
579 | } | |
580 | ||
82467a5a | 581 | for_each_cpu(cpu, drv->cpumask) { |
4c637b21 DL |
582 | device = &per_cpu(cpuidle_dev, cpu); |
583 | device->cpu = cpu; | |
584 | ||
585 | #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED | |
586 | /* | |
caf4a36e | 587 | * On multiplatform for ARM, the coupled idle states could be |
4c637b21 DL |
588 | * enabled in the kernel even if the cpuidle driver does not |
589 | * use it. Note, coupled_cpus is a struct copy. | |
590 | */ | |
591 | if (coupled_cpus) | |
592 | device->coupled_cpus = *coupled_cpus; | |
593 | #endif | |
594 | ret = cpuidle_register_device(device); | |
595 | if (!ret) | |
596 | continue; | |
597 | ||
598 | pr_err("Failed to register cpuidle device for cpu%d\n", cpu); | |
599 | ||
600 | cpuidle_unregister(drv); | |
601 | break; | |
602 | } | |
603 | ||
604 | return ret; | |
605 | } | |
606 | EXPORT_SYMBOL_GPL(cpuidle_register); | |
607 | ||
4f86d3a8 LB |
608 | #ifdef CONFIG_SMP |
609 | ||
4f86d3a8 LB |
610 | /* |
611 | * This function gets called when a part of the kernel has a new latency | |
612 | * requirement. This means we need to get all processors out of their C-state, | |
613 | * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that | |
614 | * wakes them all right up. | |
615 | */ | |
616 | static int cpuidle_latency_notify(struct notifier_block *b, | |
617 | unsigned long l, void *v) | |
618 | { | |
2ed903c5 | 619 | wake_up_all_idle_cpus(); |
4f86d3a8 LB |
620 | return NOTIFY_OK; |
621 | } | |
622 | ||
623 | static struct notifier_block cpuidle_latency_notifier = { | |
624 | .notifier_call = cpuidle_latency_notify, | |
625 | }; | |
626 | ||
d82b3518 MG |
627 | static inline void latency_notifier_init(struct notifier_block *n) |
628 | { | |
629 | pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n); | |
630 | } | |
4f86d3a8 LB |
631 | |
632 | #else /* CONFIG_SMP */ | |
633 | ||
634 | #define latency_notifier_init(x) do { } while (0) | |
635 | ||
636 | #endif /* CONFIG_SMP */ | |
637 | ||
638 | /** | |
639 | * cpuidle_init - core initializer | |
640 | */ | |
641 | static int __init cpuidle_init(void) | |
642 | { | |
643 | int ret; | |
644 | ||
62027aea LB |
645 | if (cpuidle_disabled()) |
646 | return -ENODEV; | |
647 | ||
8a25a2fd | 648 | ret = cpuidle_add_interface(cpu_subsys.dev_root); |
4f86d3a8 LB |
649 | if (ret) |
650 | return ret; | |
651 | ||
652 | latency_notifier_init(&cpuidle_latency_notifier); | |
653 | ||
654 | return 0; | |
655 | } | |
656 | ||
62027aea | 657 | module_param(off, int, 0444); |
4f86d3a8 | 658 | core_initcall(cpuidle_init); |