Commit | Line | Data |
---|---|---|
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 | |
1a022e3f BO |
47 | /** |
48 | * cpuidle_play_dead - cpu off-lining | |
49 | * | |
ee01e663 | 50 | * Returns in case of an error or no driver |
1a022e3f BO |
51 | */ |
52 | int cpuidle_play_dead(void) | |
53 | { | |
54 | struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); | |
bf4d1b5d | 55 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
8aef33a7 | 56 | int i; |
1a022e3f | 57 | |
ee01e663 TK |
58 | if (!drv) |
59 | return -ENODEV; | |
60 | ||
1a022e3f | 61 | /* Find lowest-power state that supports long-term idle */ |
8aef33a7 DL |
62 | for (i = drv->state_count - 1; i >= CPUIDLE_DRIVER_STATE_START; i--) |
63 | if (drv->states[i].enter_dead) | |
64 | return drv->states[i].enter_dead(dev, i); | |
1a022e3f BO |
65 | |
66 | return -ENODEV; | |
67 | } | |
68 | ||
a6220fc1 | 69 | /** |
38106313 RW |
70 | * cpuidle_find_deepest_state - Find deepest state meeting specific conditions. |
71 | * @drv: cpuidle driver for the given CPU. | |
72 | * @dev: cpuidle device for the given CPU. | |
124cf911 | 73 | * @freeze: Whether or not the state should be suitable for suspend-to-idle. |
a6220fc1 RW |
74 | */ |
75 | static int cpuidle_find_deepest_state(struct cpuidle_driver *drv, | |
124cf911 | 76 | struct cpuidle_device *dev, bool freeze) |
a6220fc1 RW |
77 | { |
78 | unsigned int latency_req = 0; | |
124cf911 | 79 | int i, ret = freeze ? -1 : CPUIDLE_DRIVER_STATE_START - 1; |
a6220fc1 RW |
80 | |
81 | for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) { | |
82 | struct cpuidle_state *s = &drv->states[i]; | |
83 | struct cpuidle_state_usage *su = &dev->states_usage[i]; | |
84 | ||
124cf911 RW |
85 | if (s->disabled || su->disable || s->exit_latency <= latency_req |
86 | || (freeze && !s->enter_freeze)) | |
a6220fc1 RW |
87 | continue; |
88 | ||
89 | latency_req = s->exit_latency; | |
90 | ret = i; | |
91 | } | |
92 | return ret; | |
93 | } | |
94 | ||
124cf911 RW |
95 | static void enter_freeze_proper(struct cpuidle_driver *drv, |
96 | struct cpuidle_device *dev, int index) | |
97 | { | |
98 | tick_freeze(); | |
99 | /* | |
100 | * The state used here cannot be a "coupled" one, because the "coupled" | |
101 | * cpuidle mechanism enables interrupts and doing that with timekeeping | |
102 | * suspended is generally unsafe. | |
103 | */ | |
104 | drv->states[index].enter_freeze(dev, drv, index); | |
105 | WARN_ON(!irqs_disabled()); | |
106 | /* | |
107 | * timekeeping_resume() that will be called by tick_unfreeze() for the | |
108 | * last CPU executing it calls functions containing RCU read-side | |
109 | * critical sections, so tell RCU about that. | |
110 | */ | |
111 | RCU_NONIDLE(tick_unfreeze()); | |
112 | } | |
113 | ||
38106313 RW |
114 | /** |
115 | * cpuidle_enter_freeze - Enter an idle state suitable for suspend-to-idle. | |
116 | * | |
124cf911 RW |
117 | * If there are states with the ->enter_freeze callback, find the deepest of |
118 | * them and enter it with frozen tick. Otherwise, find the deepest state | |
119 | * available and enter it normally. | |
01e04f46 RW |
120 | * |
121 | * Returns with enabled interrupts. | |
38106313 RW |
122 | */ |
123 | void cpuidle_enter_freeze(void) | |
124 | { | |
125 | struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); | |
126 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); | |
127 | int index; | |
128 | ||
124cf911 RW |
129 | /* |
130 | * Find the deepest state with ->enter_freeze present, which guarantees | |
131 | * that interrupts won't be enabled when it exits and allows the tick to | |
132 | * be frozen safely. | |
133 | */ | |
134 | index = cpuidle_find_deepest_state(drv, dev, true); | |
135 | if (index >= 0) { | |
136 | enter_freeze_proper(drv, dev, index); | |
01e04f46 | 137 | local_irq_enable(); |
124cf911 RW |
138 | return; |
139 | } | |
140 | ||
141 | /* | |
142 | * It is not safe to freeze the tick, find the deepest state available | |
143 | * at all and try to enter it normally. | |
144 | */ | |
145 | index = cpuidle_find_deepest_state(drv, dev, false); | |
38106313 RW |
146 | if (index >= 0) |
147 | cpuidle_enter(drv, dev, index); | |
148 | else | |
149 | arch_cpu_idle(); | |
38106313 RW |
150 | } |
151 | ||
56cfbf74 CC |
152 | /** |
153 | * cpuidle_enter_state - enter the state and update stats | |
154 | * @dev: cpuidle device for this cpu | |
155 | * @drv: cpuidle driver for this cpu | |
156 | * @next_state: index into drv->states of the state to enter | |
157 | */ | |
158 | int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, | |
554c06ba | 159 | int index) |
56cfbf74 CC |
160 | { |
161 | int entered_state; | |
162 | ||
554c06ba DL |
163 | struct cpuidle_state *target_state = &drv->states[index]; |
164 | ktime_t time_start, time_end; | |
165 | s64 diff; | |
166 | ||
30fe6884 | 167 | trace_cpu_idle_rcuidle(index, dev->cpu); |
554c06ba DL |
168 | time_start = ktime_get(); |
169 | ||
170 | entered_state = target_state->enter(dev, drv, index); | |
171 | ||
172 | time_end = ktime_get(); | |
30fe6884 | 173 | trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu); |
554c06ba | 174 | |
0b89e9aa PB |
175 | if (!cpuidle_state_is_coupled(dev, drv, entered_state)) |
176 | local_irq_enable(); | |
554c06ba DL |
177 | |
178 | diff = ktime_to_us(ktime_sub(time_end, time_start)); | |
179 | if (diff > INT_MAX) | |
180 | diff = INT_MAX; | |
181 | ||
182 | dev->last_residency = (int) diff; | |
56cfbf74 CC |
183 | |
184 | if (entered_state >= 0) { | |
185 | /* Update cpuidle counters */ | |
186 | /* This can be moved to within driver enter routine | |
187 | * but that results in multiple copies of same code. | |
188 | */ | |
a474a515 | 189 | dev->states_usage[entered_state].time += dev->last_residency; |
56cfbf74 CC |
190 | dev->states_usage[entered_state].usage++; |
191 | } else { | |
192 | dev->last_residency = 0; | |
193 | } | |
194 | ||
195 | return entered_state; | |
196 | } | |
197 | ||
4f86d3a8 | 198 | /** |
907e30f1 DL |
199 | * cpuidle_select - ask the cpuidle framework to choose an idle state |
200 | * | |
201 | * @drv: the cpuidle driver | |
202 | * @dev: the cpuidle device | |
4f86d3a8 | 203 | * |
907e30f1 | 204 | * Returns the index of the idle state. |
4f86d3a8 | 205 | */ |
907e30f1 | 206 | int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev) |
4f86d3a8 | 207 | { |
52c324f8 RW |
208 | if (off || !initialized) |
209 | return -ENODEV; | |
210 | ||
211 | if (!drv || !dev || !dev->enabled) | |
212 | return -EBUSY; | |
213 | ||
907e30f1 DL |
214 | return cpuidle_curr_governor->select(drv, dev); |
215 | } | |
ba8f20c2 | 216 | |
907e30f1 DL |
217 | /** |
218 | * cpuidle_enter - enter into the specified idle state | |
219 | * | |
220 | * @drv: the cpuidle driver tied with the cpu | |
221 | * @dev: the cpuidle device | |
222 | * @index: the index in the idle state table | |
223 | * | |
224 | * Returns the index in the idle state, < 0 in case of error. | |
225 | * The error code depends on the backend driver | |
226 | */ | |
227 | int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev, | |
228 | int index) | |
229 | { | |
230 | if (cpuidle_state_is_coupled(dev, drv, index)) | |
231 | return cpuidle_enter_state_coupled(dev, drv, index); | |
232 | return cpuidle_enter_state(dev, drv, index); | |
233 | } | |
b60e6a0e | 234 | |
907e30f1 DL |
235 | /** |
236 | * cpuidle_reflect - tell the underlying governor what was the state | |
237 | * we were in | |
238 | * | |
239 | * @dev : the cpuidle device | |
240 | * @index: the index in the idle state table | |
241 | * | |
242 | */ | |
243 | void cpuidle_reflect(struct cpuidle_device *dev, int index) | |
244 | { | |
38106313 | 245 | if (cpuidle_curr_governor->reflect) |
907e30f1 | 246 | cpuidle_curr_governor->reflect(dev, index); |
4f86d3a8 LB |
247 | } |
248 | ||
249 | /** | |
250 | * cpuidle_install_idle_handler - installs the cpuidle idle loop handler | |
251 | */ | |
252 | void cpuidle_install_idle_handler(void) | |
253 | { | |
a0bfa137 | 254 | if (enabled_devices) { |
4f86d3a8 LB |
255 | /* Make sure all changes finished before we switch to new idle */ |
256 | smp_wmb(); | |
a0bfa137 | 257 | initialized = 1; |
4f86d3a8 LB |
258 | } |
259 | } | |
260 | ||
261 | /** | |
262 | * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler | |
263 | */ | |
264 | void cpuidle_uninstall_idle_handler(void) | |
265 | { | |
a0bfa137 LB |
266 | if (enabled_devices) { |
267 | initialized = 0; | |
2ed903c5 | 268 | wake_up_all_idle_cpus(); |
4f86d3a8 | 269 | } |
442bf3aa DL |
270 | |
271 | /* | |
272 | * Make sure external observers (such as the scheduler) | |
273 | * are done looking at pointed idle states. | |
274 | */ | |
275 | synchronize_rcu(); | |
4f86d3a8 LB |
276 | } |
277 | ||
278 | /** | |
279 | * cpuidle_pause_and_lock - temporarily disables CPUIDLE | |
280 | */ | |
281 | void cpuidle_pause_and_lock(void) | |
282 | { | |
283 | mutex_lock(&cpuidle_lock); | |
284 | cpuidle_uninstall_idle_handler(); | |
285 | } | |
286 | ||
287 | EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock); | |
288 | ||
289 | /** | |
290 | * cpuidle_resume_and_unlock - resumes CPUIDLE operation | |
291 | */ | |
292 | void cpuidle_resume_and_unlock(void) | |
293 | { | |
294 | cpuidle_install_idle_handler(); | |
295 | mutex_unlock(&cpuidle_lock); | |
296 | } | |
297 | ||
298 | EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock); | |
299 | ||
8651f97b PM |
300 | /* Currently used in suspend/resume path to suspend cpuidle */ |
301 | void cpuidle_pause(void) | |
302 | { | |
303 | mutex_lock(&cpuidle_lock); | |
304 | cpuidle_uninstall_idle_handler(); | |
305 | mutex_unlock(&cpuidle_lock); | |
306 | } | |
307 | ||
308 | /* Currently used in suspend/resume path to resume cpuidle */ | |
309 | void cpuidle_resume(void) | |
310 | { | |
311 | mutex_lock(&cpuidle_lock); | |
312 | cpuidle_install_idle_handler(); | |
313 | mutex_unlock(&cpuidle_lock); | |
314 | } | |
315 | ||
4f86d3a8 LB |
316 | /** |
317 | * cpuidle_enable_device - enables idle PM for a CPU | |
318 | * @dev: the CPU | |
319 | * | |
320 | * This function must be called between cpuidle_pause_and_lock and | |
321 | * cpuidle_resume_and_unlock when used externally. | |
322 | */ | |
323 | int cpuidle_enable_device(struct cpuidle_device *dev) | |
324 | { | |
5df0aa73 | 325 | int ret; |
bf4d1b5d | 326 | struct cpuidle_driver *drv; |
4f86d3a8 | 327 | |
1b0a0e9a SB |
328 | if (!dev) |
329 | return -EINVAL; | |
330 | ||
4f86d3a8 LB |
331 | if (dev->enabled) |
332 | return 0; | |
bf4d1b5d DL |
333 | |
334 | drv = cpuidle_get_cpu_driver(dev); | |
335 | ||
e1689795 | 336 | if (!drv || !cpuidle_curr_governor) |
4f86d3a8 | 337 | return -EIO; |
bf4d1b5d | 338 | |
10b9d3f8 DL |
339 | if (!dev->registered) |
340 | return -EINVAL; | |
341 | ||
4f86d3a8 | 342 | if (!dev->state_count) |
fc850f39 | 343 | dev->state_count = drv->state_count; |
4f86d3a8 | 344 | |
bf4d1b5d DL |
345 | ret = cpuidle_add_device_sysfs(dev); |
346 | if (ret) | |
4f86d3a8 LB |
347 | return ret; |
348 | ||
349 | if (cpuidle_curr_governor->enable && | |
e1689795 | 350 | (ret = cpuidle_curr_governor->enable(drv, dev))) |
4f86d3a8 LB |
351 | goto fail_sysfs; |
352 | ||
4f86d3a8 LB |
353 | smp_wmb(); |
354 | ||
355 | dev->enabled = 1; | |
356 | ||
357 | enabled_devices++; | |
358 | return 0; | |
359 | ||
360 | fail_sysfs: | |
bf4d1b5d | 361 | cpuidle_remove_device_sysfs(dev); |
4f86d3a8 LB |
362 | |
363 | return ret; | |
364 | } | |
365 | ||
366 | EXPORT_SYMBOL_GPL(cpuidle_enable_device); | |
367 | ||
368 | /** | |
369 | * cpuidle_disable_device - disables idle PM for a CPU | |
370 | * @dev: the CPU | |
371 | * | |
372 | * This function must be called between cpuidle_pause_and_lock and | |
373 | * cpuidle_resume_and_unlock when used externally. | |
374 | */ | |
375 | void cpuidle_disable_device(struct cpuidle_device *dev) | |
376 | { | |
bf4d1b5d DL |
377 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
378 | ||
cf31cd1a | 379 | if (!dev || !dev->enabled) |
4f86d3a8 | 380 | return; |
bf4d1b5d DL |
381 | |
382 | if (!drv || !cpuidle_curr_governor) | |
4f86d3a8 LB |
383 | return; |
384 | ||
385 | dev->enabled = 0; | |
386 | ||
387 | if (cpuidle_curr_governor->disable) | |
bf4d1b5d | 388 | cpuidle_curr_governor->disable(drv, dev); |
4f86d3a8 | 389 | |
bf4d1b5d | 390 | cpuidle_remove_device_sysfs(dev); |
4f86d3a8 LB |
391 | enabled_devices--; |
392 | } | |
393 | ||
394 | EXPORT_SYMBOL_GPL(cpuidle_disable_device); | |
395 | ||
f6bb51a5 DL |
396 | static void __cpuidle_unregister_device(struct cpuidle_device *dev) |
397 | { | |
398 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); | |
399 | ||
400 | list_del(&dev->device_list); | |
401 | per_cpu(cpuidle_devices, dev->cpu) = NULL; | |
402 | module_put(drv->owner); | |
403 | } | |
404 | ||
267d4bf8 | 405 | static void __cpuidle_device_init(struct cpuidle_device *dev) |
5df0aa73 DL |
406 | { |
407 | memset(dev->states_usage, 0, sizeof(dev->states_usage)); | |
408 | dev->last_residency = 0; | |
5df0aa73 DL |
409 | } |
410 | ||
4f86d3a8 | 411 | /** |
dcb84f33 VP |
412 | * __cpuidle_register_device - internal register function called before register |
413 | * and enable routines | |
4f86d3a8 | 414 | * @dev: the cpu |
dcb84f33 VP |
415 | * |
416 | * cpuidle_lock mutex must be held before this is called | |
4f86d3a8 | 417 | */ |
dcb84f33 | 418 | static int __cpuidle_register_device(struct cpuidle_device *dev) |
4f86d3a8 LB |
419 | { |
420 | int ret; | |
bf4d1b5d | 421 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
4f86d3a8 | 422 | |
bf4d1b5d | 423 | if (!try_module_get(drv->owner)) |
4f86d3a8 LB |
424 | return -EINVAL; |
425 | ||
4f86d3a8 LB |
426 | per_cpu(cpuidle_devices, dev->cpu) = dev; |
427 | list_add(&dev->device_list, &cpuidle_detected_devices); | |
4f86d3a8 | 428 | |
4126c019 | 429 | ret = cpuidle_coupled_register_device(dev); |
47182668 | 430 | if (ret) |
f6bb51a5 | 431 | __cpuidle_unregister_device(dev); |
47182668 VK |
432 | else |
433 | dev->registered = 1; | |
4f86d3a8 | 434 | |
47182668 | 435 | return ret; |
dcb84f33 VP |
436 | } |
437 | ||
438 | /** | |
439 | * cpuidle_register_device - registers a CPU's idle PM feature | |
440 | * @dev: the cpu | |
441 | */ | |
442 | int cpuidle_register_device(struct cpuidle_device *dev) | |
443 | { | |
c878a52d | 444 | int ret = -EBUSY; |
dcb84f33 | 445 | |
1b0a0e9a SB |
446 | if (!dev) |
447 | return -EINVAL; | |
448 | ||
dcb84f33 VP |
449 | mutex_lock(&cpuidle_lock); |
450 | ||
c878a52d DL |
451 | if (dev->registered) |
452 | goto out_unlock; | |
453 | ||
267d4bf8 | 454 | __cpuidle_device_init(dev); |
5df0aa73 | 455 | |
f6bb51a5 DL |
456 | ret = __cpuidle_register_device(dev); |
457 | if (ret) | |
458 | goto out_unlock; | |
459 | ||
460 | ret = cpuidle_add_sysfs(dev); | |
461 | if (ret) | |
462 | goto out_unregister; | |
dcb84f33 | 463 | |
10b9d3f8 | 464 | ret = cpuidle_enable_device(dev); |
f6bb51a5 DL |
465 | if (ret) |
466 | goto out_sysfs; | |
10b9d3f8 | 467 | |
4f86d3a8 LB |
468 | cpuidle_install_idle_handler(); |
469 | ||
f6bb51a5 | 470 | out_unlock: |
4f86d3a8 LB |
471 | mutex_unlock(&cpuidle_lock); |
472 | ||
f6bb51a5 DL |
473 | return ret; |
474 | ||
475 | out_sysfs: | |
476 | cpuidle_remove_sysfs(dev); | |
477 | out_unregister: | |
478 | __cpuidle_unregister_device(dev); | |
479 | goto out_unlock; | |
4f86d3a8 LB |
480 | } |
481 | ||
482 | EXPORT_SYMBOL_GPL(cpuidle_register_device); | |
483 | ||
484 | /** | |
485 | * cpuidle_unregister_device - unregisters a CPU's idle PM feature | |
486 | * @dev: the cpu | |
487 | */ | |
488 | void cpuidle_unregister_device(struct cpuidle_device *dev) | |
489 | { | |
813e8e3d | 490 | if (!dev || dev->registered == 0) |
dcb84f33 VP |
491 | return; |
492 | ||
4f86d3a8 LB |
493 | cpuidle_pause_and_lock(); |
494 | ||
495 | cpuidle_disable_device(dev); | |
496 | ||
1aef40e2 | 497 | cpuidle_remove_sysfs(dev); |
f6bb51a5 DL |
498 | |
499 | __cpuidle_unregister_device(dev); | |
4f86d3a8 | 500 | |
4126c019 CC |
501 | cpuidle_coupled_unregister_device(dev); |
502 | ||
4f86d3a8 | 503 | cpuidle_resume_and_unlock(); |
4f86d3a8 LB |
504 | } |
505 | ||
506 | EXPORT_SYMBOL_GPL(cpuidle_unregister_device); | |
507 | ||
1c192d04 | 508 | /** |
4c637b21 DL |
509 | * cpuidle_unregister: unregister a driver and the devices. This function |
510 | * can be used only if the driver has been previously registered through | |
511 | * the cpuidle_register function. | |
512 | * | |
513 | * @drv: a valid pointer to a struct cpuidle_driver | |
514 | */ | |
515 | void cpuidle_unregister(struct cpuidle_driver *drv) | |
516 | { | |
517 | int cpu; | |
518 | struct cpuidle_device *device; | |
519 | ||
82467a5a | 520 | for_each_cpu(cpu, drv->cpumask) { |
4c637b21 DL |
521 | device = &per_cpu(cpuidle_dev, cpu); |
522 | cpuidle_unregister_device(device); | |
523 | } | |
524 | ||
525 | cpuidle_unregister_driver(drv); | |
526 | } | |
527 | EXPORT_SYMBOL_GPL(cpuidle_unregister); | |
528 | ||
529 | /** | |
530 | * cpuidle_register: registers the driver and the cpu devices with the | |
531 | * coupled_cpus passed as parameter. This function is used for all common | |
532 | * initialization pattern there are in the arch specific drivers. The | |
533 | * devices is globally defined in this file. | |
534 | * | |
535 | * @drv : a valid pointer to a struct cpuidle_driver | |
536 | * @coupled_cpus: a cpumask for the coupled states | |
537 | * | |
538 | * Returns 0 on success, < 0 otherwise | |
539 | */ | |
540 | int cpuidle_register(struct cpuidle_driver *drv, | |
541 | const struct cpumask *const coupled_cpus) | |
542 | { | |
543 | int ret, cpu; | |
544 | struct cpuidle_device *device; | |
545 | ||
546 | ret = cpuidle_register_driver(drv); | |
547 | if (ret) { | |
548 | pr_err("failed to register cpuidle driver\n"); | |
549 | return ret; | |
550 | } | |
551 | ||
82467a5a | 552 | for_each_cpu(cpu, drv->cpumask) { |
4c637b21 DL |
553 | device = &per_cpu(cpuidle_dev, cpu); |
554 | device->cpu = cpu; | |
555 | ||
556 | #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED | |
557 | /* | |
caf4a36e | 558 | * On multiplatform for ARM, the coupled idle states could be |
4c637b21 DL |
559 | * enabled in the kernel even if the cpuidle driver does not |
560 | * use it. Note, coupled_cpus is a struct copy. | |
561 | */ | |
562 | if (coupled_cpus) | |
563 | device->coupled_cpus = *coupled_cpus; | |
564 | #endif | |
565 | ret = cpuidle_register_device(device); | |
566 | if (!ret) | |
567 | continue; | |
568 | ||
569 | pr_err("Failed to register cpuidle device for cpu%d\n", cpu); | |
570 | ||
571 | cpuidle_unregister(drv); | |
572 | break; | |
573 | } | |
574 | ||
575 | return ret; | |
576 | } | |
577 | EXPORT_SYMBOL_GPL(cpuidle_register); | |
578 | ||
4f86d3a8 LB |
579 | #ifdef CONFIG_SMP |
580 | ||
4f86d3a8 LB |
581 | /* |
582 | * This function gets called when a part of the kernel has a new latency | |
583 | * requirement. This means we need to get all processors out of their C-state, | |
584 | * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that | |
585 | * wakes them all right up. | |
586 | */ | |
587 | static int cpuidle_latency_notify(struct notifier_block *b, | |
588 | unsigned long l, void *v) | |
589 | { | |
2ed903c5 | 590 | wake_up_all_idle_cpus(); |
4f86d3a8 LB |
591 | return NOTIFY_OK; |
592 | } | |
593 | ||
594 | static struct notifier_block cpuidle_latency_notifier = { | |
595 | .notifier_call = cpuidle_latency_notify, | |
596 | }; | |
597 | ||
d82b3518 MG |
598 | static inline void latency_notifier_init(struct notifier_block *n) |
599 | { | |
600 | pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n); | |
601 | } | |
4f86d3a8 LB |
602 | |
603 | #else /* CONFIG_SMP */ | |
604 | ||
605 | #define latency_notifier_init(x) do { } while (0) | |
606 | ||
607 | #endif /* CONFIG_SMP */ | |
608 | ||
609 | /** | |
610 | * cpuidle_init - core initializer | |
611 | */ | |
612 | static int __init cpuidle_init(void) | |
613 | { | |
614 | int ret; | |
615 | ||
62027aea LB |
616 | if (cpuidle_disabled()) |
617 | return -ENODEV; | |
618 | ||
8a25a2fd | 619 | ret = cpuidle_add_interface(cpu_subsys.dev_root); |
4f86d3a8 LB |
620 | if (ret) |
621 | return ret; | |
622 | ||
623 | latency_notifier_init(&cpuidle_latency_notifier); | |
624 | ||
625 | return 0; | |
626 | } | |
627 | ||
62027aea | 628 | module_param(off, int, 0444); |
4f86d3a8 | 629 | core_initcall(cpuidle_init); |