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