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