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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> | |
e6017571 | 15 | #include <linux/sched/clock.h> |
4f86d3a8 | 16 | #include <linux/notifier.h> |
e8db0be1 | 17 | #include <linux/pm_qos.h> |
4f86d3a8 LB |
18 | #include <linux/cpu.h> |
19 | #include <linux/cpuidle.h> | |
9a0b8415 | 20 | #include <linux/ktime.h> |
2e94d1f7 | 21 | #include <linux/hrtimer.h> |
884b17e1 | 22 | #include <linux/module.h> |
38106313 | 23 | #include <linux/suspend.h> |
124cf911 | 24 | #include <linux/tick.h> |
288f023e | 25 | #include <trace/events/power.h> |
4f86d3a8 LB |
26 | |
27 | #include "cpuidle.h" | |
28 | ||
29 | DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices); | |
4c637b21 | 30 | DEFINE_PER_CPU(struct cpuidle_device, cpuidle_dev); |
4f86d3a8 LB |
31 | |
32 | DEFINE_MUTEX(cpuidle_lock); | |
33 | LIST_HEAD(cpuidle_detected_devices); | |
4f86d3a8 LB |
34 | |
35 | static int enabled_devices; | |
62027aea | 36 | static int off __read_mostly; |
a0bfa137 | 37 | static int initialized __read_mostly; |
62027aea LB |
38 | |
39 | int cpuidle_disabled(void) | |
40 | { | |
41 | return off; | |
42 | } | |
d91ee586 LB |
43 | void disable_cpuidle(void) |
44 | { | |
45 | off = 1; | |
46 | } | |
4f86d3a8 | 47 | |
ef2b22ac RW |
48 | bool cpuidle_not_available(struct cpuidle_driver *drv, |
49 | struct cpuidle_device *dev) | |
31a34090 RW |
50 | { |
51 | return off || !initialized || !drv || !dev || !dev->enabled; | |
52 | } | |
53 | ||
1a022e3f BO |
54 | /** |
55 | * cpuidle_play_dead - cpu off-lining | |
56 | * | |
ee01e663 | 57 | * Returns in case of an error or no driver |
1a022e3f BO |
58 | */ |
59 | int cpuidle_play_dead(void) | |
60 | { | |
61 | struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); | |
bf4d1b5d | 62 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
8aef33a7 | 63 | int i; |
1a022e3f | 64 | |
ee01e663 TK |
65 | if (!drv) |
66 | return -ENODEV; | |
67 | ||
1a022e3f | 68 | /* Find lowest-power state that supports long-term idle */ |
7d51d979 | 69 | for (i = drv->state_count - 1; i >= 0; i--) |
8aef33a7 DL |
70 | if (drv->states[i].enter_dead) |
71 | return drv->states[i].enter_dead(dev, i); | |
1a022e3f BO |
72 | |
73 | return -ENODEV; | |
74 | } | |
75 | ||
ef2b22ac | 76 | static int find_deepest_state(struct cpuidle_driver *drv, |
0d94039f RW |
77 | struct cpuidle_device *dev, |
78 | unsigned int max_latency, | |
79 | unsigned int forbidden_flags, | |
80 | bool freeze) | |
a6220fc1 RW |
81 | { |
82 | unsigned int latency_req = 0; | |
51164251 | 83 | int i, ret = 0; |
a6220fc1 | 84 | |
51164251 | 85 | for (i = 1; i < drv->state_count; i++) { |
a6220fc1 RW |
86 | struct cpuidle_state *s = &drv->states[i]; |
87 | struct cpuidle_state_usage *su = &dev->states_usage[i]; | |
88 | ||
124cf911 | 89 | if (s->disabled || su->disable || s->exit_latency <= latency_req |
0d94039f RW |
90 | || s->exit_latency > max_latency |
91 | || (s->flags & forbidden_flags) | |
124cf911 | 92 | || (freeze && !s->enter_freeze)) |
a6220fc1 RW |
93 | continue; |
94 | ||
95 | latency_req = s->exit_latency; | |
96 | ret = i; | |
97 | } | |
98 | return ret; | |
99 | } | |
100 | ||
0e7414b7 RW |
101 | /** |
102 | * cpuidle_use_deepest_state - Set/clear governor override flag. | |
103 | * @enable: New value of the flag. | |
104 | * | |
105 | * Set/unset the current CPU to use the deepest idle state (override governors | |
106 | * going forward if set). | |
107 | */ | |
bb8313b6 JP |
108 | void cpuidle_use_deepest_state(bool enable) |
109 | { | |
110 | struct cpuidle_device *dev; | |
111 | ||
112 | preempt_disable(); | |
113 | dev = cpuidle_get_device(); | |
114 | dev->use_deepest_state = enable; | |
115 | preempt_enable(); | |
116 | } | |
117 | ||
ef2b22ac RW |
118 | /** |
119 | * cpuidle_find_deepest_state - Find the deepest available idle state. | |
120 | * @drv: cpuidle driver for the given CPU. | |
121 | * @dev: cpuidle device for the given CPU. | |
122 | */ | |
123 | int cpuidle_find_deepest_state(struct cpuidle_driver *drv, | |
124 | struct cpuidle_device *dev) | |
125 | { | |
0d94039f | 126 | return find_deepest_state(drv, dev, UINT_MAX, 0, false); |
ef2b22ac RW |
127 | } |
128 | ||
bb8313b6 | 129 | #ifdef CONFIG_SUSPEND |
124cf911 RW |
130 | static void enter_freeze_proper(struct cpuidle_driver *drv, |
131 | struct cpuidle_device *dev, int index) | |
132 | { | |
ae0afb4f RW |
133 | /* |
134 | * trace_suspend_resume() called by tick_freeze() for the last CPU | |
135 | * executing it contains RCU usage regarded as invalid in the idle | |
136 | * context, so tell RCU about that. | |
137 | */ | |
138 | RCU_NONIDLE(tick_freeze()); | |
124cf911 RW |
139 | /* |
140 | * The state used here cannot be a "coupled" one, because the "coupled" | |
141 | * cpuidle mechanism enables interrupts and doing that with timekeeping | |
142 | * suspended is generally unsafe. | |
143 | */ | |
63caae84 | 144 | stop_critical_timings(); |
124cf911 RW |
145 | drv->states[index].enter_freeze(dev, drv, index); |
146 | WARN_ON(!irqs_disabled()); | |
147 | /* | |
148 | * timekeeping_resume() that will be called by tick_unfreeze() for the | |
ae0afb4f | 149 | * first CPU executing it calls functions containing RCU read-side |
124cf911 RW |
150 | * critical sections, so tell RCU about that. |
151 | */ | |
152 | RCU_NONIDLE(tick_unfreeze()); | |
63caae84 | 153 | start_critical_timings(); |
124cf911 RW |
154 | } |
155 | ||
38106313 RW |
156 | /** |
157 | * cpuidle_enter_freeze - Enter an idle state suitable for suspend-to-idle. | |
ef2b22ac RW |
158 | * @drv: cpuidle driver for the given CPU. |
159 | * @dev: cpuidle device for the given CPU. | |
38106313 | 160 | * |
124cf911 | 161 | * If there are states with the ->enter_freeze callback, find the deepest of |
ef2b22ac | 162 | * them and enter it with frozen tick. |
38106313 | 163 | */ |
ef2b22ac | 164 | int cpuidle_enter_freeze(struct cpuidle_driver *drv, struct cpuidle_device *dev) |
38106313 | 165 | { |
38106313 RW |
166 | int index; |
167 | ||
124cf911 RW |
168 | /* |
169 | * Find the deepest state with ->enter_freeze present, which guarantees | |
170 | * that interrupts won't be enabled when it exits and allows the tick to | |
171 | * be frozen safely. | |
172 | */ | |
0d94039f | 173 | index = find_deepest_state(drv, dev, UINT_MAX, 0, true); |
6f16886b | 174 | if (index > 0) |
124cf911 | 175 | enter_freeze_proper(drv, dev, index); |
124cf911 | 176 | |
ef2b22ac | 177 | return index; |
38106313 | 178 | } |
87e9b9f1 | 179 | #endif /* CONFIG_SUSPEND */ |
38106313 | 180 | |
56cfbf74 CC |
181 | /** |
182 | * cpuidle_enter_state - enter the state and update stats | |
183 | * @dev: cpuidle device for this cpu | |
184 | * @drv: cpuidle driver for this cpu | |
7312280b | 185 | * @index: index into the states table in @drv of the state to enter |
56cfbf74 CC |
186 | */ |
187 | int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, | |
554c06ba | 188 | int index) |
56cfbf74 CC |
189 | { |
190 | int entered_state; | |
191 | ||
554c06ba | 192 | struct cpuidle_state *target_state = &drv->states[index]; |
df8d9eea | 193 | bool broadcast = !!(target_state->flags & CPUIDLE_FLAG_TIMER_STOP); |
dbd1b8ea | 194 | ktime_t time_start, time_end; |
554c06ba DL |
195 | s64 diff; |
196 | ||
df8d9eea RW |
197 | /* |
198 | * Tell the time framework to switch to a broadcast timer because our | |
199 | * local timer will be shut down. If a local timer is used from another | |
200 | * CPU as a broadcast timer, this call may fail if it is not available. | |
201 | */ | |
827a5aef | 202 | if (broadcast && tick_broadcast_enter()) { |
0d94039f RW |
203 | index = find_deepest_state(drv, dev, target_state->exit_latency, |
204 | CPUIDLE_FLAG_TIMER_STOP, false); | |
205 | if (index < 0) { | |
206 | default_idle_call(); | |
207 | return -EBUSY; | |
208 | } | |
209 | target_state = &drv->states[index]; | |
827a5aef | 210 | } |
df8d9eea | 211 | |
faad3849 RW |
212 | /* Take note of the planned idle state. */ |
213 | sched_idle_set_state(target_state); | |
214 | ||
30fe6884 | 215 | trace_cpu_idle_rcuidle(index, dev->cpu); |
dbd1b8ea | 216 | time_start = ns_to_ktime(local_clock()); |
554c06ba | 217 | |
63caae84 | 218 | stop_critical_timings(); |
554c06ba | 219 | entered_state = target_state->enter(dev, drv, index); |
63caae84 | 220 | start_critical_timings(); |
554c06ba | 221 | |
dbd1b8ea | 222 | time_end = ns_to_ktime(local_clock()); |
30fe6884 | 223 | trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu); |
554c06ba | 224 | |
faad3849 RW |
225 | /* The cpu is no longer idle or about to enter idle. */ |
226 | sched_idle_set_state(NULL); | |
227 | ||
df8d9eea RW |
228 | if (broadcast) { |
229 | if (WARN_ON_ONCE(!irqs_disabled())) | |
230 | local_irq_disable(); | |
231 | ||
232 | tick_broadcast_exit(); | |
233 | } | |
234 | ||
e7387da5 | 235 | if (!cpuidle_state_is_coupled(drv, index)) |
0b89e9aa | 236 | local_irq_enable(); |
554c06ba | 237 | |
dbd1b8ea | 238 | diff = ktime_us_delta(time_end, time_start); |
554c06ba DL |
239 | if (diff > INT_MAX) |
240 | diff = INT_MAX; | |
241 | ||
242 | dev->last_residency = (int) diff; | |
56cfbf74 CC |
243 | |
244 | if (entered_state >= 0) { | |
245 | /* Update cpuidle counters */ | |
246 | /* This can be moved to within driver enter routine | |
247 | * but that results in multiple copies of same code. | |
248 | */ | |
a474a515 | 249 | dev->states_usage[entered_state].time += dev->last_residency; |
56cfbf74 CC |
250 | dev->states_usage[entered_state].usage++; |
251 | } else { | |
252 | dev->last_residency = 0; | |
253 | } | |
254 | ||
255 | return entered_state; | |
256 | } | |
257 | ||
4f86d3a8 | 258 | /** |
907e30f1 DL |
259 | * cpuidle_select - ask the cpuidle framework to choose an idle state |
260 | * | |
261 | * @drv: the cpuidle driver | |
262 | * @dev: the cpuidle device | |
4f86d3a8 | 263 | * |
51164251 | 264 | * Returns the index of the idle state. The return value must not be negative. |
4f86d3a8 | 265 | */ |
907e30f1 | 266 | int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev) |
4f86d3a8 | 267 | { |
907e30f1 DL |
268 | return cpuidle_curr_governor->select(drv, dev); |
269 | } | |
ba8f20c2 | 270 | |
907e30f1 DL |
271 | /** |
272 | * cpuidle_enter - enter into the specified idle state | |
273 | * | |
274 | * @drv: the cpuidle driver tied with the cpu | |
275 | * @dev: the cpuidle device | |
276 | * @index: the index in the idle state table | |
277 | * | |
278 | * Returns the index in the idle state, < 0 in case of error. | |
279 | * The error code depends on the backend driver | |
280 | */ | |
281 | int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev, | |
282 | int index) | |
283 | { | |
4c1ed5a6 | 284 | if (cpuidle_state_is_coupled(drv, index)) |
907e30f1 DL |
285 | return cpuidle_enter_state_coupled(dev, drv, index); |
286 | return cpuidle_enter_state(dev, drv, index); | |
287 | } | |
b60e6a0e | 288 | |
907e30f1 DL |
289 | /** |
290 | * cpuidle_reflect - tell the underlying governor what was the state | |
291 | * we were in | |
292 | * | |
293 | * @dev : the cpuidle device | |
294 | * @index: the index in the idle state table | |
295 | * | |
296 | */ | |
297 | void cpuidle_reflect(struct cpuidle_device *dev, int index) | |
298 | { | |
a802ea96 | 299 | if (cpuidle_curr_governor->reflect && index >= 0) |
907e30f1 | 300 | cpuidle_curr_governor->reflect(dev, index); |
4f86d3a8 LB |
301 | } |
302 | ||
303 | /** | |
304 | * cpuidle_install_idle_handler - installs the cpuidle idle loop handler | |
305 | */ | |
306 | void cpuidle_install_idle_handler(void) | |
307 | { | |
a0bfa137 | 308 | if (enabled_devices) { |
4f86d3a8 LB |
309 | /* Make sure all changes finished before we switch to new idle */ |
310 | smp_wmb(); | |
a0bfa137 | 311 | initialized = 1; |
4f86d3a8 LB |
312 | } |
313 | } | |
314 | ||
315 | /** | |
316 | * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler | |
317 | */ | |
318 | void cpuidle_uninstall_idle_handler(void) | |
319 | { | |
a0bfa137 LB |
320 | if (enabled_devices) { |
321 | initialized = 0; | |
2ed903c5 | 322 | wake_up_all_idle_cpus(); |
4f86d3a8 | 323 | } |
442bf3aa DL |
324 | |
325 | /* | |
326 | * Make sure external observers (such as the scheduler) | |
327 | * are done looking at pointed idle states. | |
328 | */ | |
329 | synchronize_rcu(); | |
4f86d3a8 LB |
330 | } |
331 | ||
332 | /** | |
333 | * cpuidle_pause_and_lock - temporarily disables CPUIDLE | |
334 | */ | |
335 | void cpuidle_pause_and_lock(void) | |
336 | { | |
337 | mutex_lock(&cpuidle_lock); | |
338 | cpuidle_uninstall_idle_handler(); | |
339 | } | |
340 | ||
341 | EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock); | |
342 | ||
343 | /** | |
344 | * cpuidle_resume_and_unlock - resumes CPUIDLE operation | |
345 | */ | |
346 | void cpuidle_resume_and_unlock(void) | |
347 | { | |
348 | cpuidle_install_idle_handler(); | |
349 | mutex_unlock(&cpuidle_lock); | |
350 | } | |
351 | ||
352 | EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock); | |
353 | ||
8651f97b PM |
354 | /* Currently used in suspend/resume path to suspend cpuidle */ |
355 | void cpuidle_pause(void) | |
356 | { | |
357 | mutex_lock(&cpuidle_lock); | |
358 | cpuidle_uninstall_idle_handler(); | |
359 | mutex_unlock(&cpuidle_lock); | |
360 | } | |
361 | ||
362 | /* Currently used in suspend/resume path to resume cpuidle */ | |
363 | void cpuidle_resume(void) | |
364 | { | |
365 | mutex_lock(&cpuidle_lock); | |
366 | cpuidle_install_idle_handler(); | |
367 | mutex_unlock(&cpuidle_lock); | |
368 | } | |
369 | ||
4f86d3a8 LB |
370 | /** |
371 | * cpuidle_enable_device - enables idle PM for a CPU | |
372 | * @dev: the CPU | |
373 | * | |
374 | * This function must be called between cpuidle_pause_and_lock and | |
375 | * cpuidle_resume_and_unlock when used externally. | |
376 | */ | |
377 | int cpuidle_enable_device(struct cpuidle_device *dev) | |
378 | { | |
5df0aa73 | 379 | int ret; |
bf4d1b5d | 380 | struct cpuidle_driver *drv; |
4f86d3a8 | 381 | |
1b0a0e9a SB |
382 | if (!dev) |
383 | return -EINVAL; | |
384 | ||
4f86d3a8 LB |
385 | if (dev->enabled) |
386 | return 0; | |
bf4d1b5d DL |
387 | |
388 | drv = cpuidle_get_cpu_driver(dev); | |
389 | ||
e1689795 | 390 | if (!drv || !cpuidle_curr_governor) |
4f86d3a8 | 391 | return -EIO; |
bf4d1b5d | 392 | |
10b9d3f8 DL |
393 | if (!dev->registered) |
394 | return -EINVAL; | |
395 | ||
bf4d1b5d DL |
396 | ret = cpuidle_add_device_sysfs(dev); |
397 | if (ret) | |
4f86d3a8 LB |
398 | return ret; |
399 | ||
400 | if (cpuidle_curr_governor->enable && | |
e1689795 | 401 | (ret = cpuidle_curr_governor->enable(drv, dev))) |
4f86d3a8 LB |
402 | goto fail_sysfs; |
403 | ||
4f86d3a8 LB |
404 | smp_wmb(); |
405 | ||
406 | dev->enabled = 1; | |
407 | ||
408 | enabled_devices++; | |
409 | return 0; | |
410 | ||
411 | fail_sysfs: | |
bf4d1b5d | 412 | cpuidle_remove_device_sysfs(dev); |
4f86d3a8 LB |
413 | |
414 | return ret; | |
415 | } | |
416 | ||
417 | EXPORT_SYMBOL_GPL(cpuidle_enable_device); | |
418 | ||
419 | /** | |
420 | * cpuidle_disable_device - disables idle PM for a CPU | |
421 | * @dev: the CPU | |
422 | * | |
423 | * This function must be called between cpuidle_pause_and_lock and | |
424 | * cpuidle_resume_and_unlock when used externally. | |
425 | */ | |
426 | void cpuidle_disable_device(struct cpuidle_device *dev) | |
427 | { | |
bf4d1b5d DL |
428 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
429 | ||
cf31cd1a | 430 | if (!dev || !dev->enabled) |
4f86d3a8 | 431 | return; |
bf4d1b5d DL |
432 | |
433 | if (!drv || !cpuidle_curr_governor) | |
4f86d3a8 LB |
434 | return; |
435 | ||
436 | dev->enabled = 0; | |
437 | ||
438 | if (cpuidle_curr_governor->disable) | |
bf4d1b5d | 439 | cpuidle_curr_governor->disable(drv, dev); |
4f86d3a8 | 440 | |
bf4d1b5d | 441 | cpuidle_remove_device_sysfs(dev); |
4f86d3a8 LB |
442 | enabled_devices--; |
443 | } | |
444 | ||
445 | EXPORT_SYMBOL_GPL(cpuidle_disable_device); | |
446 | ||
f6bb51a5 DL |
447 | static void __cpuidle_unregister_device(struct cpuidle_device *dev) |
448 | { | |
449 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); | |
450 | ||
451 | list_del(&dev->device_list); | |
452 | per_cpu(cpuidle_devices, dev->cpu) = NULL; | |
453 | module_put(drv->owner); | |
c998c078 DG |
454 | |
455 | dev->registered = 0; | |
f6bb51a5 DL |
456 | } |
457 | ||
267d4bf8 | 458 | static void __cpuidle_device_init(struct cpuidle_device *dev) |
5df0aa73 DL |
459 | { |
460 | memset(dev->states_usage, 0, sizeof(dev->states_usage)); | |
461 | dev->last_residency = 0; | |
5df0aa73 DL |
462 | } |
463 | ||
4f86d3a8 | 464 | /** |
dcb84f33 VP |
465 | * __cpuidle_register_device - internal register function called before register |
466 | * and enable routines | |
4f86d3a8 | 467 | * @dev: the cpu |
dcb84f33 VP |
468 | * |
469 | * cpuidle_lock mutex must be held before this is called | |
4f86d3a8 | 470 | */ |
dcb84f33 | 471 | static int __cpuidle_register_device(struct cpuidle_device *dev) |
4f86d3a8 LB |
472 | { |
473 | int ret; | |
bf4d1b5d | 474 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
4f86d3a8 | 475 | |
bf4d1b5d | 476 | if (!try_module_get(drv->owner)) |
4f86d3a8 LB |
477 | return -EINVAL; |
478 | ||
4f86d3a8 LB |
479 | per_cpu(cpuidle_devices, dev->cpu) = dev; |
480 | list_add(&dev->device_list, &cpuidle_detected_devices); | |
4f86d3a8 | 481 | |
4126c019 | 482 | ret = cpuidle_coupled_register_device(dev); |
47182668 | 483 | if (ret) |
f6bb51a5 | 484 | __cpuidle_unregister_device(dev); |
47182668 VK |
485 | else |
486 | dev->registered = 1; | |
4f86d3a8 | 487 | |
47182668 | 488 | return ret; |
dcb84f33 VP |
489 | } |
490 | ||
491 | /** | |
492 | * cpuidle_register_device - registers a CPU's idle PM feature | |
493 | * @dev: the cpu | |
494 | */ | |
495 | int cpuidle_register_device(struct cpuidle_device *dev) | |
496 | { | |
c878a52d | 497 | int ret = -EBUSY; |
dcb84f33 | 498 | |
1b0a0e9a SB |
499 | if (!dev) |
500 | return -EINVAL; | |
501 | ||
dcb84f33 VP |
502 | mutex_lock(&cpuidle_lock); |
503 | ||
c878a52d DL |
504 | if (dev->registered) |
505 | goto out_unlock; | |
506 | ||
267d4bf8 | 507 | __cpuidle_device_init(dev); |
5df0aa73 | 508 | |
f6bb51a5 DL |
509 | ret = __cpuidle_register_device(dev); |
510 | if (ret) | |
511 | goto out_unlock; | |
512 | ||
513 | ret = cpuidle_add_sysfs(dev); | |
514 | if (ret) | |
515 | goto out_unregister; | |
dcb84f33 | 516 | |
10b9d3f8 | 517 | ret = cpuidle_enable_device(dev); |
f6bb51a5 DL |
518 | if (ret) |
519 | goto out_sysfs; | |
10b9d3f8 | 520 | |
4f86d3a8 LB |
521 | cpuidle_install_idle_handler(); |
522 | ||
f6bb51a5 | 523 | out_unlock: |
4f86d3a8 LB |
524 | mutex_unlock(&cpuidle_lock); |
525 | ||
f6bb51a5 DL |
526 | return ret; |
527 | ||
528 | out_sysfs: | |
529 | cpuidle_remove_sysfs(dev); | |
530 | out_unregister: | |
531 | __cpuidle_unregister_device(dev); | |
532 | goto out_unlock; | |
4f86d3a8 LB |
533 | } |
534 | ||
535 | EXPORT_SYMBOL_GPL(cpuidle_register_device); | |
536 | ||
537 | /** | |
538 | * cpuidle_unregister_device - unregisters a CPU's idle PM feature | |
539 | * @dev: the cpu | |
540 | */ | |
541 | void cpuidle_unregister_device(struct cpuidle_device *dev) | |
542 | { | |
813e8e3d | 543 | if (!dev || dev->registered == 0) |
dcb84f33 VP |
544 | return; |
545 | ||
4f86d3a8 LB |
546 | cpuidle_pause_and_lock(); |
547 | ||
548 | cpuidle_disable_device(dev); | |
549 | ||
1aef40e2 | 550 | cpuidle_remove_sysfs(dev); |
f6bb51a5 DL |
551 | |
552 | __cpuidle_unregister_device(dev); | |
4f86d3a8 | 553 | |
4126c019 CC |
554 | cpuidle_coupled_unregister_device(dev); |
555 | ||
4f86d3a8 | 556 | cpuidle_resume_and_unlock(); |
4f86d3a8 LB |
557 | } |
558 | ||
559 | EXPORT_SYMBOL_GPL(cpuidle_unregister_device); | |
560 | ||
1c192d04 | 561 | /** |
4c637b21 DL |
562 | * cpuidle_unregister: unregister a driver and the devices. This function |
563 | * can be used only if the driver has been previously registered through | |
564 | * the cpuidle_register function. | |
565 | * | |
566 | * @drv: a valid pointer to a struct cpuidle_driver | |
567 | */ | |
568 | void cpuidle_unregister(struct cpuidle_driver *drv) | |
569 | { | |
570 | int cpu; | |
571 | struct cpuidle_device *device; | |
572 | ||
82467a5a | 573 | for_each_cpu(cpu, drv->cpumask) { |
4c637b21 DL |
574 | device = &per_cpu(cpuidle_dev, cpu); |
575 | cpuidle_unregister_device(device); | |
576 | } | |
577 | ||
578 | cpuidle_unregister_driver(drv); | |
579 | } | |
580 | EXPORT_SYMBOL_GPL(cpuidle_unregister); | |
581 | ||
582 | /** | |
583 | * cpuidle_register: registers the driver and the cpu devices with the | |
584 | * coupled_cpus passed as parameter. This function is used for all common | |
585 | * initialization pattern there are in the arch specific drivers. The | |
586 | * devices is globally defined in this file. | |
587 | * | |
588 | * @drv : a valid pointer to a struct cpuidle_driver | |
589 | * @coupled_cpus: a cpumask for the coupled states | |
590 | * | |
591 | * Returns 0 on success, < 0 otherwise | |
592 | */ | |
593 | int cpuidle_register(struct cpuidle_driver *drv, | |
594 | const struct cpumask *const coupled_cpus) | |
595 | { | |
596 | int ret, cpu; | |
597 | struct cpuidle_device *device; | |
598 | ||
599 | ret = cpuidle_register_driver(drv); | |
600 | if (ret) { | |
601 | pr_err("failed to register cpuidle driver\n"); | |
602 | return ret; | |
603 | } | |
604 | ||
82467a5a | 605 | for_each_cpu(cpu, drv->cpumask) { |
4c637b21 DL |
606 | device = &per_cpu(cpuidle_dev, cpu); |
607 | device->cpu = cpu; | |
608 | ||
609 | #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED | |
610 | /* | |
caf4a36e | 611 | * On multiplatform for ARM, the coupled idle states could be |
4c637b21 DL |
612 | * enabled in the kernel even if the cpuidle driver does not |
613 | * use it. Note, coupled_cpus is a struct copy. | |
614 | */ | |
615 | if (coupled_cpus) | |
616 | device->coupled_cpus = *coupled_cpus; | |
617 | #endif | |
618 | ret = cpuidle_register_device(device); | |
619 | if (!ret) | |
620 | continue; | |
621 | ||
622 | pr_err("Failed to register cpuidle device for cpu%d\n", cpu); | |
623 | ||
624 | cpuidle_unregister(drv); | |
625 | break; | |
626 | } | |
627 | ||
628 | return ret; | |
629 | } | |
630 | EXPORT_SYMBOL_GPL(cpuidle_register); | |
631 | ||
4f86d3a8 LB |
632 | #ifdef CONFIG_SMP |
633 | ||
4f86d3a8 LB |
634 | /* |
635 | * This function gets called when a part of the kernel has a new latency | |
636 | * requirement. This means we need to get all processors out of their C-state, | |
637 | * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that | |
638 | * wakes them all right up. | |
639 | */ | |
640 | static int cpuidle_latency_notify(struct notifier_block *b, | |
641 | unsigned long l, void *v) | |
642 | { | |
2ed903c5 | 643 | wake_up_all_idle_cpus(); |
4f86d3a8 LB |
644 | return NOTIFY_OK; |
645 | } | |
646 | ||
647 | static struct notifier_block cpuidle_latency_notifier = { | |
648 | .notifier_call = cpuidle_latency_notify, | |
649 | }; | |
650 | ||
d82b3518 MG |
651 | static inline void latency_notifier_init(struct notifier_block *n) |
652 | { | |
653 | pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n); | |
654 | } | |
4f86d3a8 LB |
655 | |
656 | #else /* CONFIG_SMP */ | |
657 | ||
658 | #define latency_notifier_init(x) do { } while (0) | |
659 | ||
660 | #endif /* CONFIG_SMP */ | |
661 | ||
662 | /** | |
663 | * cpuidle_init - core initializer | |
664 | */ | |
665 | static int __init cpuidle_init(void) | |
666 | { | |
667 | int ret; | |
668 | ||
62027aea LB |
669 | if (cpuidle_disabled()) |
670 | return -ENODEV; | |
671 | ||
8a25a2fd | 672 | ret = cpuidle_add_interface(cpu_subsys.dev_root); |
4f86d3a8 LB |
673 | if (ret) |
674 | return ret; | |
675 | ||
676 | latency_notifier_init(&cpuidle_latency_notifier); | |
677 | ||
678 | return 0; | |
679 | } | |
680 | ||
62027aea | 681 | module_param(off, int, 0444); |
4f86d3a8 | 682 | core_initcall(cpuidle_init); |