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> |
288f023e | 22 | #include <trace/events/power.h> |
4f86d3a8 LB |
23 | |
24 | #include "cpuidle.h" | |
25 | ||
26 | DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices); | |
4c637b21 | 27 | DEFINE_PER_CPU(struct cpuidle_device, cpuidle_dev); |
4f86d3a8 LB |
28 | |
29 | DEFINE_MUTEX(cpuidle_lock); | |
30 | LIST_HEAD(cpuidle_detected_devices); | |
4f86d3a8 LB |
31 | |
32 | static int enabled_devices; | |
62027aea | 33 | static int off __read_mostly; |
a0bfa137 | 34 | static int initialized __read_mostly; |
62027aea LB |
35 | |
36 | int cpuidle_disabled(void) | |
37 | { | |
38 | return off; | |
39 | } | |
d91ee586 LB |
40 | void disable_cpuidle(void) |
41 | { | |
42 | off = 1; | |
43 | } | |
4f86d3a8 | 44 | |
dcb84f33 VP |
45 | static int __cpuidle_register_device(struct cpuidle_device *dev); |
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 | ||
56cfbf74 CC |
69 | /** |
70 | * cpuidle_enter_state - enter the state and update stats | |
71 | * @dev: cpuidle device for this cpu | |
72 | * @drv: cpuidle driver for this cpu | |
73 | * @next_state: index into drv->states of the state to enter | |
74 | */ | |
75 | int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, | |
554c06ba | 76 | int index) |
56cfbf74 CC |
77 | { |
78 | int entered_state; | |
79 | ||
554c06ba DL |
80 | struct cpuidle_state *target_state = &drv->states[index]; |
81 | ktime_t time_start, time_end; | |
82 | s64 diff; | |
83 | ||
84 | time_start = ktime_get(); | |
85 | ||
86 | entered_state = target_state->enter(dev, drv, index); | |
87 | ||
88 | time_end = ktime_get(); | |
89 | ||
90 | local_irq_enable(); | |
91 | ||
92 | diff = ktime_to_us(ktime_sub(time_end, time_start)); | |
93 | if (diff > INT_MAX) | |
94 | diff = INT_MAX; | |
95 | ||
96 | dev->last_residency = (int) diff; | |
56cfbf74 CC |
97 | |
98 | if (entered_state >= 0) { | |
99 | /* Update cpuidle counters */ | |
100 | /* This can be moved to within driver enter routine | |
101 | * but that results in multiple copies of same code. | |
102 | */ | |
a474a515 | 103 | dev->states_usage[entered_state].time += dev->last_residency; |
56cfbf74 CC |
104 | dev->states_usage[entered_state].usage++; |
105 | } else { | |
106 | dev->last_residency = 0; | |
107 | } | |
108 | ||
109 | return entered_state; | |
110 | } | |
111 | ||
4f86d3a8 LB |
112 | /** |
113 | * cpuidle_idle_call - the main idle loop | |
114 | * | |
115 | * NOTE: no locks or semaphores should be used here | |
a0bfa137 | 116 | * return non-zero on failure |
4f86d3a8 | 117 | */ |
a0bfa137 | 118 | int cpuidle_idle_call(void) |
4f86d3a8 | 119 | { |
4a6f4fe8 | 120 | struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); |
bf4d1b5d | 121 | struct cpuidle_driver *drv; |
e978aa7d | 122 | int next_state, entered_state; |
4f86d3a8 | 123 | |
a0bfa137 LB |
124 | if (off) |
125 | return -ENODEV; | |
126 | ||
127 | if (!initialized) | |
128 | return -ENODEV; | |
129 | ||
4f86d3a8 | 130 | /* check if the device is ready */ |
a0bfa137 LB |
131 | if (!dev || !dev->enabled) |
132 | return -EBUSY; | |
4f86d3a8 | 133 | |
bf4d1b5d DL |
134 | drv = cpuidle_get_cpu_driver(dev); |
135 | ||
4f86d3a8 | 136 | /* ask the governor for the next state */ |
46bcfad7 | 137 | next_state = cpuidle_curr_governor->select(drv, dev); |
246eb7f0 | 138 | if (need_resched()) { |
d73d68dc YS |
139 | dev->last_residency = 0; |
140 | /* give the governor an opportunity to reflect on the outcome */ | |
141 | if (cpuidle_curr_governor->reflect) | |
142 | cpuidle_curr_governor->reflect(dev, next_state); | |
246eb7f0 | 143 | local_irq_enable(); |
a0bfa137 | 144 | return 0; |
246eb7f0 KH |
145 | } |
146 | ||
76027ea8 | 147 | trace_cpu_idle_rcuidle(next_state, dev->cpu); |
f77cfe4e | 148 | |
b60e6a0e DL |
149 | if (drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP) |
150 | clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, | |
151 | &dev->cpu); | |
152 | ||
4126c019 CC |
153 | if (cpuidle_state_is_coupled(dev, drv, next_state)) |
154 | entered_state = cpuidle_enter_state_coupled(dev, drv, | |
155 | next_state); | |
156 | else | |
157 | entered_state = cpuidle_enter_state(dev, drv, next_state); | |
f77cfe4e | 158 | |
b60e6a0e DL |
159 | if (drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP) |
160 | clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, | |
161 | &dev->cpu); | |
162 | ||
76027ea8 | 163 | trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu); |
f77cfe4e | 164 | |
4f86d3a8 LB |
165 | /* give the governor an opportunity to reflect on the outcome */ |
166 | if (cpuidle_curr_governor->reflect) | |
e978aa7d | 167 | cpuidle_curr_governor->reflect(dev, entered_state); |
a0bfa137 LB |
168 | |
169 | return 0; | |
4f86d3a8 LB |
170 | } |
171 | ||
172 | /** | |
173 | * cpuidle_install_idle_handler - installs the cpuidle idle loop handler | |
174 | */ | |
175 | void cpuidle_install_idle_handler(void) | |
176 | { | |
a0bfa137 | 177 | if (enabled_devices) { |
4f86d3a8 LB |
178 | /* Make sure all changes finished before we switch to new idle */ |
179 | smp_wmb(); | |
a0bfa137 | 180 | initialized = 1; |
4f86d3a8 LB |
181 | } |
182 | } | |
183 | ||
184 | /** | |
185 | * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler | |
186 | */ | |
187 | void cpuidle_uninstall_idle_handler(void) | |
188 | { | |
a0bfa137 LB |
189 | if (enabled_devices) { |
190 | initialized = 0; | |
4a162513 | 191 | kick_all_cpus_sync(); |
4f86d3a8 LB |
192 | } |
193 | } | |
194 | ||
195 | /** | |
196 | * cpuidle_pause_and_lock - temporarily disables CPUIDLE | |
197 | */ | |
198 | void cpuidle_pause_and_lock(void) | |
199 | { | |
200 | mutex_lock(&cpuidle_lock); | |
201 | cpuidle_uninstall_idle_handler(); | |
202 | } | |
203 | ||
204 | EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock); | |
205 | ||
206 | /** | |
207 | * cpuidle_resume_and_unlock - resumes CPUIDLE operation | |
208 | */ | |
209 | void cpuidle_resume_and_unlock(void) | |
210 | { | |
211 | cpuidle_install_idle_handler(); | |
212 | mutex_unlock(&cpuidle_lock); | |
213 | } | |
214 | ||
215 | EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock); | |
216 | ||
8651f97b PM |
217 | /* Currently used in suspend/resume path to suspend cpuidle */ |
218 | void cpuidle_pause(void) | |
219 | { | |
220 | mutex_lock(&cpuidle_lock); | |
221 | cpuidle_uninstall_idle_handler(); | |
222 | mutex_unlock(&cpuidle_lock); | |
223 | } | |
224 | ||
225 | /* Currently used in suspend/resume path to resume cpuidle */ | |
226 | void cpuidle_resume(void) | |
227 | { | |
228 | mutex_lock(&cpuidle_lock); | |
229 | cpuidle_install_idle_handler(); | |
230 | mutex_unlock(&cpuidle_lock); | |
231 | } | |
232 | ||
d8c216cf | 233 | #ifdef CONFIG_ARCH_HAS_CPU_RELAX |
46bcfad7 DD |
234 | static int poll_idle(struct cpuidle_device *dev, |
235 | struct cpuidle_driver *drv, int index) | |
d8c216cf RW |
236 | { |
237 | ktime_t t1, t2; | |
238 | s64 diff; | |
d8c216cf RW |
239 | |
240 | t1 = ktime_get(); | |
241 | local_irq_enable(); | |
242 | while (!need_resched()) | |
243 | cpu_relax(); | |
244 | ||
245 | t2 = ktime_get(); | |
246 | diff = ktime_to_us(ktime_sub(t2, t1)); | |
247 | if (diff > INT_MAX) | |
248 | diff = INT_MAX; | |
249 | ||
e978aa7d DD |
250 | dev->last_residency = (int) diff; |
251 | ||
252 | return index; | |
d8c216cf RW |
253 | } |
254 | ||
46bcfad7 | 255 | static void poll_idle_init(struct cpuidle_driver *drv) |
d8c216cf | 256 | { |
46bcfad7 | 257 | struct cpuidle_state *state = &drv->states[0]; |
d8c216cf | 258 | |
720f1c30 | 259 | snprintf(state->name, CPUIDLE_NAME_LEN, "POLL"); |
d8c216cf RW |
260 | snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE"); |
261 | state->exit_latency = 0; | |
262 | state->target_residency = 0; | |
263 | state->power_usage = -1; | |
d247632c | 264 | state->flags = 0; |
d8c216cf | 265 | state->enter = poll_idle; |
cbc9ef02 | 266 | state->disabled = false; |
d8c216cf RW |
267 | } |
268 | #else | |
46bcfad7 | 269 | static void poll_idle_init(struct cpuidle_driver *drv) {} |
d8c216cf RW |
270 | #endif /* CONFIG_ARCH_HAS_CPU_RELAX */ |
271 | ||
4f86d3a8 LB |
272 | /** |
273 | * cpuidle_enable_device - enables idle PM for a CPU | |
274 | * @dev: the CPU | |
275 | * | |
276 | * This function must be called between cpuidle_pause_and_lock and | |
277 | * cpuidle_resume_and_unlock when used externally. | |
278 | */ | |
279 | int cpuidle_enable_device(struct cpuidle_device *dev) | |
280 | { | |
281 | int ret, i; | |
bf4d1b5d | 282 | struct cpuidle_driver *drv; |
4f86d3a8 | 283 | |
1b0a0e9a SB |
284 | if (!dev) |
285 | return -EINVAL; | |
286 | ||
4f86d3a8 LB |
287 | if (dev->enabled) |
288 | return 0; | |
bf4d1b5d DL |
289 | |
290 | drv = cpuidle_get_cpu_driver(dev); | |
291 | ||
e1689795 | 292 | if (!drv || !cpuidle_curr_governor) |
4f86d3a8 | 293 | return -EIO; |
bf4d1b5d | 294 | |
4f86d3a8 | 295 | if (!dev->state_count) |
fc850f39 | 296 | dev->state_count = drv->state_count; |
4f86d3a8 | 297 | |
dcb84f33 VP |
298 | if (dev->registered == 0) { |
299 | ret = __cpuidle_register_device(dev); | |
300 | if (ret) | |
301 | return ret; | |
302 | } | |
303 | ||
e1689795 | 304 | poll_idle_init(drv); |
d8c216cf | 305 | |
bf4d1b5d DL |
306 | ret = cpuidle_add_device_sysfs(dev); |
307 | if (ret) | |
4f86d3a8 LB |
308 | return ret; |
309 | ||
310 | if (cpuidle_curr_governor->enable && | |
e1689795 | 311 | (ret = cpuidle_curr_governor->enable(drv, dev))) |
4f86d3a8 LB |
312 | goto fail_sysfs; |
313 | ||
314 | for (i = 0; i < dev->state_count; i++) { | |
4202735e DD |
315 | dev->states_usage[i].usage = 0; |
316 | dev->states_usage[i].time = 0; | |
4f86d3a8 LB |
317 | } |
318 | dev->last_residency = 0; | |
4f86d3a8 LB |
319 | |
320 | smp_wmb(); | |
321 | ||
322 | dev->enabled = 1; | |
323 | ||
324 | enabled_devices++; | |
325 | return 0; | |
326 | ||
327 | fail_sysfs: | |
bf4d1b5d | 328 | cpuidle_remove_device_sysfs(dev); |
4f86d3a8 LB |
329 | |
330 | return ret; | |
331 | } | |
332 | ||
333 | EXPORT_SYMBOL_GPL(cpuidle_enable_device); | |
334 | ||
335 | /** | |
336 | * cpuidle_disable_device - disables idle PM for a CPU | |
337 | * @dev: the CPU | |
338 | * | |
339 | * This function must be called between cpuidle_pause_and_lock and | |
340 | * cpuidle_resume_and_unlock when used externally. | |
341 | */ | |
342 | void cpuidle_disable_device(struct cpuidle_device *dev) | |
343 | { | |
bf4d1b5d DL |
344 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
345 | ||
cf31cd1a | 346 | if (!dev || !dev->enabled) |
4f86d3a8 | 347 | return; |
bf4d1b5d DL |
348 | |
349 | if (!drv || !cpuidle_curr_governor) | |
4f86d3a8 LB |
350 | return; |
351 | ||
352 | dev->enabled = 0; | |
353 | ||
354 | if (cpuidle_curr_governor->disable) | |
bf4d1b5d | 355 | cpuidle_curr_governor->disable(drv, dev); |
4f86d3a8 | 356 | |
bf4d1b5d | 357 | cpuidle_remove_device_sysfs(dev); |
4f86d3a8 LB |
358 | enabled_devices--; |
359 | } | |
360 | ||
361 | EXPORT_SYMBOL_GPL(cpuidle_disable_device); | |
362 | ||
363 | /** | |
dcb84f33 VP |
364 | * __cpuidle_register_device - internal register function called before register |
365 | * and enable routines | |
4f86d3a8 | 366 | * @dev: the cpu |
dcb84f33 VP |
367 | * |
368 | * cpuidle_lock mutex must be held before this is called | |
4f86d3a8 | 369 | */ |
dcb84f33 | 370 | static int __cpuidle_register_device(struct cpuidle_device *dev) |
4f86d3a8 LB |
371 | { |
372 | int ret; | |
bf4d1b5d | 373 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
4f86d3a8 | 374 | |
bf4d1b5d | 375 | if (!try_module_get(drv->owner)) |
4f86d3a8 LB |
376 | return -EINVAL; |
377 | ||
4f86d3a8 LB |
378 | per_cpu(cpuidle_devices, dev->cpu) = dev; |
379 | list_add(&dev->device_list, &cpuidle_detected_devices); | |
1aef40e2 | 380 | ret = cpuidle_add_sysfs(dev); |
3af272ab CC |
381 | if (ret) |
382 | goto err_sysfs; | |
4f86d3a8 | 383 | |
4126c019 CC |
384 | ret = cpuidle_coupled_register_device(dev); |
385 | if (ret) | |
386 | goto err_coupled; | |
4f86d3a8 | 387 | |
dcb84f33 VP |
388 | dev->registered = 1; |
389 | return 0; | |
3af272ab | 390 | |
4126c019 | 391 | err_coupled: |
1aef40e2 | 392 | cpuidle_remove_sysfs(dev); |
3af272ab CC |
393 | err_sysfs: |
394 | list_del(&dev->device_list); | |
395 | per_cpu(cpuidle_devices, dev->cpu) = NULL; | |
bf4d1b5d | 396 | module_put(drv->owner); |
3af272ab | 397 | return ret; |
dcb84f33 VP |
398 | } |
399 | ||
400 | /** | |
401 | * cpuidle_register_device - registers a CPU's idle PM feature | |
402 | * @dev: the cpu | |
403 | */ | |
404 | int cpuidle_register_device(struct cpuidle_device *dev) | |
405 | { | |
406 | int ret; | |
407 | ||
1b0a0e9a SB |
408 | if (!dev) |
409 | return -EINVAL; | |
410 | ||
dcb84f33 VP |
411 | mutex_lock(&cpuidle_lock); |
412 | ||
413 | if ((ret = __cpuidle_register_device(dev))) { | |
414 | mutex_unlock(&cpuidle_lock); | |
415 | return ret; | |
416 | } | |
417 | ||
4f86d3a8 LB |
418 | cpuidle_enable_device(dev); |
419 | cpuidle_install_idle_handler(); | |
420 | ||
421 | mutex_unlock(&cpuidle_lock); | |
422 | ||
423 | return 0; | |
424 | ||
425 | } | |
426 | ||
427 | EXPORT_SYMBOL_GPL(cpuidle_register_device); | |
428 | ||
429 | /** | |
430 | * cpuidle_unregister_device - unregisters a CPU's idle PM feature | |
431 | * @dev: the cpu | |
432 | */ | |
433 | void cpuidle_unregister_device(struct cpuidle_device *dev) | |
434 | { | |
bf4d1b5d | 435 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
4f86d3a8 | 436 | |
dcb84f33 VP |
437 | if (dev->registered == 0) |
438 | return; | |
439 | ||
4f86d3a8 LB |
440 | cpuidle_pause_and_lock(); |
441 | ||
442 | cpuidle_disable_device(dev); | |
443 | ||
1aef40e2 | 444 | cpuidle_remove_sysfs(dev); |
4f86d3a8 | 445 | list_del(&dev->device_list); |
4f86d3a8 LB |
446 | per_cpu(cpuidle_devices, dev->cpu) = NULL; |
447 | ||
4126c019 CC |
448 | cpuidle_coupled_unregister_device(dev); |
449 | ||
4f86d3a8 LB |
450 | cpuidle_resume_and_unlock(); |
451 | ||
bf4d1b5d | 452 | module_put(drv->owner); |
4f86d3a8 LB |
453 | } |
454 | ||
455 | EXPORT_SYMBOL_GPL(cpuidle_unregister_device); | |
456 | ||
1c192d04 | 457 | /** |
4c637b21 DL |
458 | * cpuidle_unregister: unregister a driver and the devices. This function |
459 | * can be used only if the driver has been previously registered through | |
460 | * the cpuidle_register function. | |
461 | * | |
462 | * @drv: a valid pointer to a struct cpuidle_driver | |
463 | */ | |
464 | void cpuidle_unregister(struct cpuidle_driver *drv) | |
465 | { | |
466 | int cpu; | |
467 | struct cpuidle_device *device; | |
468 | ||
469 | for_each_possible_cpu(cpu) { | |
470 | device = &per_cpu(cpuidle_dev, cpu); | |
471 | cpuidle_unregister_device(device); | |
472 | } | |
473 | ||
474 | cpuidle_unregister_driver(drv); | |
475 | } | |
476 | EXPORT_SYMBOL_GPL(cpuidle_unregister); | |
477 | ||
478 | /** | |
479 | * cpuidle_register: registers the driver and the cpu devices with the | |
480 | * coupled_cpus passed as parameter. This function is used for all common | |
481 | * initialization pattern there are in the arch specific drivers. The | |
482 | * devices is globally defined in this file. | |
483 | * | |
484 | * @drv : a valid pointer to a struct cpuidle_driver | |
485 | * @coupled_cpus: a cpumask for the coupled states | |
486 | * | |
487 | * Returns 0 on success, < 0 otherwise | |
488 | */ | |
489 | int cpuidle_register(struct cpuidle_driver *drv, | |
490 | const struct cpumask *const coupled_cpus) | |
491 | { | |
492 | int ret, cpu; | |
493 | struct cpuidle_device *device; | |
494 | ||
495 | ret = cpuidle_register_driver(drv); | |
496 | if (ret) { | |
497 | pr_err("failed to register cpuidle driver\n"); | |
498 | return ret; | |
499 | } | |
500 | ||
501 | for_each_possible_cpu(cpu) { | |
502 | device = &per_cpu(cpuidle_dev, cpu); | |
503 | device->cpu = cpu; | |
504 | ||
505 | #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED | |
506 | /* | |
507 | * On multiplatform for ARM, the coupled idle states could | |
508 | * enabled in the kernel even if the cpuidle driver does not | |
509 | * use it. Note, coupled_cpus is a struct copy. | |
510 | */ | |
511 | if (coupled_cpus) | |
512 | device->coupled_cpus = *coupled_cpus; | |
513 | #endif | |
514 | ret = cpuidle_register_device(device); | |
515 | if (!ret) | |
516 | continue; | |
517 | ||
518 | pr_err("Failed to register cpuidle device for cpu%d\n", cpu); | |
519 | ||
520 | cpuidle_unregister(drv); | |
521 | break; | |
522 | } | |
523 | ||
524 | return ret; | |
525 | } | |
526 | EXPORT_SYMBOL_GPL(cpuidle_register); | |
527 | ||
4f86d3a8 LB |
528 | #ifdef CONFIG_SMP |
529 | ||
530 | static void smp_callback(void *v) | |
531 | { | |
532 | /* we already woke the CPU up, nothing more to do */ | |
533 | } | |
534 | ||
535 | /* | |
536 | * This function gets called when a part of the kernel has a new latency | |
537 | * requirement. This means we need to get all processors out of their C-state, | |
538 | * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that | |
539 | * wakes them all right up. | |
540 | */ | |
541 | static int cpuidle_latency_notify(struct notifier_block *b, | |
542 | unsigned long l, void *v) | |
543 | { | |
8691e5a8 | 544 | smp_call_function(smp_callback, NULL, 1); |
4f86d3a8 LB |
545 | return NOTIFY_OK; |
546 | } | |
547 | ||
548 | static struct notifier_block cpuidle_latency_notifier = { | |
549 | .notifier_call = cpuidle_latency_notify, | |
550 | }; | |
551 | ||
d82b3518 MG |
552 | static inline void latency_notifier_init(struct notifier_block *n) |
553 | { | |
554 | pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n); | |
555 | } | |
4f86d3a8 LB |
556 | |
557 | #else /* CONFIG_SMP */ | |
558 | ||
559 | #define latency_notifier_init(x) do { } while (0) | |
560 | ||
561 | #endif /* CONFIG_SMP */ | |
562 | ||
563 | /** | |
564 | * cpuidle_init - core initializer | |
565 | */ | |
566 | static int __init cpuidle_init(void) | |
567 | { | |
568 | int ret; | |
569 | ||
62027aea LB |
570 | if (cpuidle_disabled()) |
571 | return -ENODEV; | |
572 | ||
8a25a2fd | 573 | ret = cpuidle_add_interface(cpu_subsys.dev_root); |
4f86d3a8 LB |
574 | if (ret) |
575 | return ret; | |
576 | ||
577 | latency_notifier_init(&cpuidle_latency_notifier); | |
578 | ||
579 | return 0; | |
580 | } | |
581 | ||
62027aea | 582 | module_param(off, int, 0444); |
4f86d3a8 | 583 | core_initcall(cpuidle_init); |