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; |
a6220fc1 | 35 | static bool use_deepest_state __read_mostly; |
62027aea LB |
36 | |
37 | int cpuidle_disabled(void) | |
38 | { | |
39 | return off; | |
40 | } | |
d91ee586 LB |
41 | void disable_cpuidle(void) |
42 | { | |
43 | off = 1; | |
44 | } | |
4f86d3a8 | 45 | |
1a022e3f BO |
46 | /** |
47 | * cpuidle_play_dead - cpu off-lining | |
48 | * | |
ee01e663 | 49 | * Returns in case of an error or no driver |
1a022e3f BO |
50 | */ |
51 | int cpuidle_play_dead(void) | |
52 | { | |
53 | struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); | |
bf4d1b5d | 54 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
8aef33a7 | 55 | int i; |
1a022e3f | 56 | |
ee01e663 TK |
57 | if (!drv) |
58 | return -ENODEV; | |
59 | ||
1a022e3f | 60 | /* Find lowest-power state that supports long-term idle */ |
8aef33a7 DL |
61 | for (i = drv->state_count - 1; i >= CPUIDLE_DRIVER_STATE_START; i--) |
62 | if (drv->states[i].enter_dead) | |
63 | return drv->states[i].enter_dead(dev, i); | |
1a022e3f BO |
64 | |
65 | return -ENODEV; | |
66 | } | |
67 | ||
a6220fc1 RW |
68 | /** |
69 | * cpuidle_use_deepest_state - Enable/disable the "deepest idle" mode. | |
70 | * @enable: Whether enable or disable the feature. | |
71 | * | |
72 | * If the "deepest idle" mode is enabled, cpuidle will ignore the governor and | |
73 | * always use the state with the greatest exit latency (out of the states that | |
74 | * are not disabled). | |
75 | * | |
76 | * This function can only be called after cpuidle_pause() to avoid races. | |
77 | */ | |
78 | void cpuidle_use_deepest_state(bool enable) | |
79 | { | |
80 | use_deepest_state = enable; | |
81 | } | |
82 | ||
83 | /** | |
84 | * cpuidle_find_deepest_state - Find the state of the greatest exit latency. | |
85 | * @drv: cpuidle driver for a given CPU. | |
86 | * @dev: cpuidle device for a given CPU. | |
87 | */ | |
88 | static int cpuidle_find_deepest_state(struct cpuidle_driver *drv, | |
89 | struct cpuidle_device *dev) | |
90 | { | |
91 | unsigned int latency_req = 0; | |
92 | int i, ret = CPUIDLE_DRIVER_STATE_START - 1; | |
93 | ||
94 | for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) { | |
95 | struct cpuidle_state *s = &drv->states[i]; | |
96 | struct cpuidle_state_usage *su = &dev->states_usage[i]; | |
97 | ||
98 | if (s->disabled || su->disable || s->exit_latency <= latency_req) | |
99 | continue; | |
100 | ||
101 | latency_req = s->exit_latency; | |
102 | ret = i; | |
103 | } | |
104 | return ret; | |
105 | } | |
106 | ||
56cfbf74 CC |
107 | /** |
108 | * cpuidle_enter_state - enter the state and update stats | |
109 | * @dev: cpuidle device for this cpu | |
110 | * @drv: cpuidle driver for this cpu | |
111 | * @next_state: index into drv->states of the state to enter | |
112 | */ | |
113 | int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, | |
554c06ba | 114 | int index) |
56cfbf74 CC |
115 | { |
116 | int entered_state; | |
117 | ||
554c06ba DL |
118 | struct cpuidle_state *target_state = &drv->states[index]; |
119 | ktime_t time_start, time_end; | |
120 | s64 diff; | |
121 | ||
122 | time_start = ktime_get(); | |
123 | ||
124 | entered_state = target_state->enter(dev, drv, index); | |
125 | ||
126 | time_end = ktime_get(); | |
127 | ||
0b89e9aa PB |
128 | if (!cpuidle_state_is_coupled(dev, drv, entered_state)) |
129 | local_irq_enable(); | |
554c06ba DL |
130 | |
131 | diff = ktime_to_us(ktime_sub(time_end, time_start)); | |
132 | if (diff > INT_MAX) | |
133 | diff = INT_MAX; | |
134 | ||
135 | dev->last_residency = (int) diff; | |
56cfbf74 CC |
136 | |
137 | if (entered_state >= 0) { | |
138 | /* Update cpuidle counters */ | |
139 | /* This can be moved to within driver enter routine | |
140 | * but that results in multiple copies of same code. | |
141 | */ | |
a474a515 | 142 | dev->states_usage[entered_state].time += dev->last_residency; |
56cfbf74 CC |
143 | dev->states_usage[entered_state].usage++; |
144 | } else { | |
145 | dev->last_residency = 0; | |
146 | } | |
147 | ||
148 | return entered_state; | |
149 | } | |
150 | ||
4f86d3a8 | 151 | /** |
907e30f1 DL |
152 | * cpuidle_select - ask the cpuidle framework to choose an idle state |
153 | * | |
154 | * @drv: the cpuidle driver | |
155 | * @dev: the cpuidle device | |
4f86d3a8 | 156 | * |
907e30f1 | 157 | * Returns the index of the idle state. |
4f86d3a8 | 158 | */ |
907e30f1 | 159 | int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev) |
4f86d3a8 | 160 | { |
52c324f8 RW |
161 | if (off || !initialized) |
162 | return -ENODEV; | |
163 | ||
164 | if (!drv || !dev || !dev->enabled) | |
165 | return -EBUSY; | |
166 | ||
a6220fc1 RW |
167 | if (unlikely(use_deepest_state)) |
168 | return cpuidle_find_deepest_state(drv, dev); | |
169 | ||
907e30f1 DL |
170 | return cpuidle_curr_governor->select(drv, dev); |
171 | } | |
ba8f20c2 | 172 | |
907e30f1 DL |
173 | /** |
174 | * cpuidle_enter - enter into the specified idle state | |
175 | * | |
176 | * @drv: the cpuidle driver tied with the cpu | |
177 | * @dev: the cpuidle device | |
178 | * @index: the index in the idle state table | |
179 | * | |
180 | * Returns the index in the idle state, < 0 in case of error. | |
181 | * The error code depends on the backend driver | |
182 | */ | |
183 | int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev, | |
184 | int index) | |
185 | { | |
186 | if (cpuidle_state_is_coupled(dev, drv, index)) | |
187 | return cpuidle_enter_state_coupled(dev, drv, index); | |
188 | return cpuidle_enter_state(dev, drv, index); | |
189 | } | |
b60e6a0e | 190 | |
907e30f1 DL |
191 | /** |
192 | * cpuidle_reflect - tell the underlying governor what was the state | |
193 | * we were in | |
194 | * | |
195 | * @dev : the cpuidle device | |
196 | * @index: the index in the idle state table | |
197 | * | |
198 | */ | |
199 | void cpuidle_reflect(struct cpuidle_device *dev, int index) | |
200 | { | |
a6220fc1 | 201 | if (cpuidle_curr_governor->reflect && !unlikely(use_deepest_state)) |
907e30f1 | 202 | cpuidle_curr_governor->reflect(dev, index); |
4f86d3a8 LB |
203 | } |
204 | ||
205 | /** | |
206 | * cpuidle_install_idle_handler - installs the cpuidle idle loop handler | |
207 | */ | |
208 | void cpuidle_install_idle_handler(void) | |
209 | { | |
a0bfa137 | 210 | if (enabled_devices) { |
4f86d3a8 LB |
211 | /* Make sure all changes finished before we switch to new idle */ |
212 | smp_wmb(); | |
a0bfa137 | 213 | initialized = 1; |
4f86d3a8 LB |
214 | } |
215 | } | |
216 | ||
217 | /** | |
218 | * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler | |
219 | */ | |
220 | void cpuidle_uninstall_idle_handler(void) | |
221 | { | |
a0bfa137 LB |
222 | if (enabled_devices) { |
223 | initialized = 0; | |
4a162513 | 224 | kick_all_cpus_sync(); |
4f86d3a8 LB |
225 | } |
226 | } | |
227 | ||
228 | /** | |
229 | * cpuidle_pause_and_lock - temporarily disables CPUIDLE | |
230 | */ | |
231 | void cpuidle_pause_and_lock(void) | |
232 | { | |
233 | mutex_lock(&cpuidle_lock); | |
234 | cpuidle_uninstall_idle_handler(); | |
235 | } | |
236 | ||
237 | EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock); | |
238 | ||
239 | /** | |
240 | * cpuidle_resume_and_unlock - resumes CPUIDLE operation | |
241 | */ | |
242 | void cpuidle_resume_and_unlock(void) | |
243 | { | |
244 | cpuidle_install_idle_handler(); | |
245 | mutex_unlock(&cpuidle_lock); | |
246 | } | |
247 | ||
248 | EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock); | |
249 | ||
8651f97b PM |
250 | /* Currently used in suspend/resume path to suspend cpuidle */ |
251 | void cpuidle_pause(void) | |
252 | { | |
253 | mutex_lock(&cpuidle_lock); | |
254 | cpuidle_uninstall_idle_handler(); | |
255 | mutex_unlock(&cpuidle_lock); | |
256 | } | |
257 | ||
258 | /* Currently used in suspend/resume path to resume cpuidle */ | |
259 | void cpuidle_resume(void) | |
260 | { | |
261 | mutex_lock(&cpuidle_lock); | |
262 | cpuidle_install_idle_handler(); | |
263 | mutex_unlock(&cpuidle_lock); | |
264 | } | |
265 | ||
4f86d3a8 LB |
266 | /** |
267 | * cpuidle_enable_device - enables idle PM for a CPU | |
268 | * @dev: the CPU | |
269 | * | |
270 | * This function must be called between cpuidle_pause_and_lock and | |
271 | * cpuidle_resume_and_unlock when used externally. | |
272 | */ | |
273 | int cpuidle_enable_device(struct cpuidle_device *dev) | |
274 | { | |
5df0aa73 | 275 | int ret; |
bf4d1b5d | 276 | struct cpuidle_driver *drv; |
4f86d3a8 | 277 | |
1b0a0e9a SB |
278 | if (!dev) |
279 | return -EINVAL; | |
280 | ||
4f86d3a8 LB |
281 | if (dev->enabled) |
282 | return 0; | |
bf4d1b5d DL |
283 | |
284 | drv = cpuidle_get_cpu_driver(dev); | |
285 | ||
e1689795 | 286 | if (!drv || !cpuidle_curr_governor) |
4f86d3a8 | 287 | return -EIO; |
bf4d1b5d | 288 | |
10b9d3f8 DL |
289 | if (!dev->registered) |
290 | return -EINVAL; | |
291 | ||
4f86d3a8 | 292 | if (!dev->state_count) |
fc850f39 | 293 | dev->state_count = drv->state_count; |
4f86d3a8 | 294 | |
bf4d1b5d DL |
295 | ret = cpuidle_add_device_sysfs(dev); |
296 | if (ret) | |
4f86d3a8 LB |
297 | return ret; |
298 | ||
299 | if (cpuidle_curr_governor->enable && | |
e1689795 | 300 | (ret = cpuidle_curr_governor->enable(drv, dev))) |
4f86d3a8 LB |
301 | goto fail_sysfs; |
302 | ||
4f86d3a8 LB |
303 | smp_wmb(); |
304 | ||
305 | dev->enabled = 1; | |
306 | ||
307 | enabled_devices++; | |
308 | return 0; | |
309 | ||
310 | fail_sysfs: | |
bf4d1b5d | 311 | cpuidle_remove_device_sysfs(dev); |
4f86d3a8 LB |
312 | |
313 | return ret; | |
314 | } | |
315 | ||
316 | EXPORT_SYMBOL_GPL(cpuidle_enable_device); | |
317 | ||
318 | /** | |
319 | * cpuidle_disable_device - disables idle PM for a CPU | |
320 | * @dev: the CPU | |
321 | * | |
322 | * This function must be called between cpuidle_pause_and_lock and | |
323 | * cpuidle_resume_and_unlock when used externally. | |
324 | */ | |
325 | void cpuidle_disable_device(struct cpuidle_device *dev) | |
326 | { | |
bf4d1b5d DL |
327 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
328 | ||
cf31cd1a | 329 | if (!dev || !dev->enabled) |
4f86d3a8 | 330 | return; |
bf4d1b5d DL |
331 | |
332 | if (!drv || !cpuidle_curr_governor) | |
4f86d3a8 LB |
333 | return; |
334 | ||
335 | dev->enabled = 0; | |
336 | ||
337 | if (cpuidle_curr_governor->disable) | |
bf4d1b5d | 338 | cpuidle_curr_governor->disable(drv, dev); |
4f86d3a8 | 339 | |
bf4d1b5d | 340 | cpuidle_remove_device_sysfs(dev); |
4f86d3a8 LB |
341 | enabled_devices--; |
342 | } | |
343 | ||
344 | EXPORT_SYMBOL_GPL(cpuidle_disable_device); | |
345 | ||
f6bb51a5 DL |
346 | static void __cpuidle_unregister_device(struct cpuidle_device *dev) |
347 | { | |
348 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); | |
349 | ||
350 | list_del(&dev->device_list); | |
351 | per_cpu(cpuidle_devices, dev->cpu) = NULL; | |
352 | module_put(drv->owner); | |
353 | } | |
354 | ||
267d4bf8 | 355 | static void __cpuidle_device_init(struct cpuidle_device *dev) |
5df0aa73 DL |
356 | { |
357 | memset(dev->states_usage, 0, sizeof(dev->states_usage)); | |
358 | dev->last_residency = 0; | |
5df0aa73 DL |
359 | } |
360 | ||
4f86d3a8 | 361 | /** |
dcb84f33 VP |
362 | * __cpuidle_register_device - internal register function called before register |
363 | * and enable routines | |
4f86d3a8 | 364 | * @dev: the cpu |
dcb84f33 VP |
365 | * |
366 | * cpuidle_lock mutex must be held before this is called | |
4f86d3a8 | 367 | */ |
dcb84f33 | 368 | static int __cpuidle_register_device(struct cpuidle_device *dev) |
4f86d3a8 LB |
369 | { |
370 | int ret; | |
bf4d1b5d | 371 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
4f86d3a8 | 372 | |
bf4d1b5d | 373 | if (!try_module_get(drv->owner)) |
4f86d3a8 LB |
374 | return -EINVAL; |
375 | ||
4f86d3a8 LB |
376 | per_cpu(cpuidle_devices, dev->cpu) = dev; |
377 | list_add(&dev->device_list, &cpuidle_detected_devices); | |
4f86d3a8 | 378 | |
4126c019 | 379 | ret = cpuidle_coupled_register_device(dev); |
47182668 | 380 | if (ret) |
f6bb51a5 | 381 | __cpuidle_unregister_device(dev); |
47182668 VK |
382 | else |
383 | dev->registered = 1; | |
4f86d3a8 | 384 | |
47182668 | 385 | return ret; |
dcb84f33 VP |
386 | } |
387 | ||
388 | /** | |
389 | * cpuidle_register_device - registers a CPU's idle PM feature | |
390 | * @dev: the cpu | |
391 | */ | |
392 | int cpuidle_register_device(struct cpuidle_device *dev) | |
393 | { | |
c878a52d | 394 | int ret = -EBUSY; |
dcb84f33 | 395 | |
1b0a0e9a SB |
396 | if (!dev) |
397 | return -EINVAL; | |
398 | ||
dcb84f33 VP |
399 | mutex_lock(&cpuidle_lock); |
400 | ||
c878a52d DL |
401 | if (dev->registered) |
402 | goto out_unlock; | |
403 | ||
267d4bf8 | 404 | __cpuidle_device_init(dev); |
5df0aa73 | 405 | |
f6bb51a5 DL |
406 | ret = __cpuidle_register_device(dev); |
407 | if (ret) | |
408 | goto out_unlock; | |
409 | ||
410 | ret = cpuidle_add_sysfs(dev); | |
411 | if (ret) | |
412 | goto out_unregister; | |
dcb84f33 | 413 | |
10b9d3f8 | 414 | ret = cpuidle_enable_device(dev); |
f6bb51a5 DL |
415 | if (ret) |
416 | goto out_sysfs; | |
10b9d3f8 | 417 | |
4f86d3a8 LB |
418 | cpuidle_install_idle_handler(); |
419 | ||
f6bb51a5 | 420 | out_unlock: |
4f86d3a8 LB |
421 | mutex_unlock(&cpuidle_lock); |
422 | ||
f6bb51a5 DL |
423 | return ret; |
424 | ||
425 | out_sysfs: | |
426 | cpuidle_remove_sysfs(dev); | |
427 | out_unregister: | |
428 | __cpuidle_unregister_device(dev); | |
429 | goto out_unlock; | |
4f86d3a8 LB |
430 | } |
431 | ||
432 | EXPORT_SYMBOL_GPL(cpuidle_register_device); | |
433 | ||
434 | /** | |
435 | * cpuidle_unregister_device - unregisters a CPU's idle PM feature | |
436 | * @dev: the cpu | |
437 | */ | |
438 | void cpuidle_unregister_device(struct cpuidle_device *dev) | |
439 | { | |
813e8e3d | 440 | if (!dev || dev->registered == 0) |
dcb84f33 VP |
441 | return; |
442 | ||
4f86d3a8 LB |
443 | cpuidle_pause_and_lock(); |
444 | ||
445 | cpuidle_disable_device(dev); | |
446 | ||
1aef40e2 | 447 | cpuidle_remove_sysfs(dev); |
f6bb51a5 DL |
448 | |
449 | __cpuidle_unregister_device(dev); | |
4f86d3a8 | 450 | |
4126c019 CC |
451 | cpuidle_coupled_unregister_device(dev); |
452 | ||
4f86d3a8 | 453 | cpuidle_resume_and_unlock(); |
4f86d3a8 LB |
454 | } |
455 | ||
456 | EXPORT_SYMBOL_GPL(cpuidle_unregister_device); | |
457 | ||
1c192d04 | 458 | /** |
4c637b21 DL |
459 | * cpuidle_unregister: unregister a driver and the devices. This function |
460 | * can be used only if the driver has been previously registered through | |
461 | * the cpuidle_register function. | |
462 | * | |
463 | * @drv: a valid pointer to a struct cpuidle_driver | |
464 | */ | |
465 | void cpuidle_unregister(struct cpuidle_driver *drv) | |
466 | { | |
467 | int cpu; | |
468 | struct cpuidle_device *device; | |
469 | ||
82467a5a | 470 | for_each_cpu(cpu, drv->cpumask) { |
4c637b21 DL |
471 | device = &per_cpu(cpuidle_dev, cpu); |
472 | cpuidle_unregister_device(device); | |
473 | } | |
474 | ||
475 | cpuidle_unregister_driver(drv); | |
476 | } | |
477 | EXPORT_SYMBOL_GPL(cpuidle_unregister); | |
478 | ||
479 | /** | |
480 | * cpuidle_register: registers the driver and the cpu devices with the | |
481 | * coupled_cpus passed as parameter. This function is used for all common | |
482 | * initialization pattern there are in the arch specific drivers. The | |
483 | * devices is globally defined in this file. | |
484 | * | |
485 | * @drv : a valid pointer to a struct cpuidle_driver | |
486 | * @coupled_cpus: a cpumask for the coupled states | |
487 | * | |
488 | * Returns 0 on success, < 0 otherwise | |
489 | */ | |
490 | int cpuidle_register(struct cpuidle_driver *drv, | |
491 | const struct cpumask *const coupled_cpus) | |
492 | { | |
493 | int ret, cpu; | |
494 | struct cpuidle_device *device; | |
495 | ||
496 | ret = cpuidle_register_driver(drv); | |
497 | if (ret) { | |
498 | pr_err("failed to register cpuidle driver\n"); | |
499 | return ret; | |
500 | } | |
501 | ||
82467a5a | 502 | for_each_cpu(cpu, drv->cpumask) { |
4c637b21 DL |
503 | device = &per_cpu(cpuidle_dev, cpu); |
504 | device->cpu = cpu; | |
505 | ||
506 | #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED | |
507 | /* | |
caf4a36e | 508 | * On multiplatform for ARM, the coupled idle states could be |
4c637b21 DL |
509 | * enabled in the kernel even if the cpuidle driver does not |
510 | * use it. Note, coupled_cpus is a struct copy. | |
511 | */ | |
512 | if (coupled_cpus) | |
513 | device->coupled_cpus = *coupled_cpus; | |
514 | #endif | |
515 | ret = cpuidle_register_device(device); | |
516 | if (!ret) | |
517 | continue; | |
518 | ||
519 | pr_err("Failed to register cpuidle device for cpu%d\n", cpu); | |
520 | ||
521 | cpuidle_unregister(drv); | |
522 | break; | |
523 | } | |
524 | ||
525 | return ret; | |
526 | } | |
527 | EXPORT_SYMBOL_GPL(cpuidle_register); | |
528 | ||
4f86d3a8 LB |
529 | #ifdef CONFIG_SMP |
530 | ||
531 | static void smp_callback(void *v) | |
532 | { | |
533 | /* we already woke the CPU up, nothing more to do */ | |
534 | } | |
535 | ||
536 | /* | |
537 | * This function gets called when a part of the kernel has a new latency | |
538 | * requirement. This means we need to get all processors out of their C-state, | |
539 | * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that | |
540 | * wakes them all right up. | |
541 | */ | |
542 | static int cpuidle_latency_notify(struct notifier_block *b, | |
543 | unsigned long l, void *v) | |
544 | { | |
8691e5a8 | 545 | smp_call_function(smp_callback, NULL, 1); |
4f86d3a8 LB |
546 | return NOTIFY_OK; |
547 | } | |
548 | ||
549 | static struct notifier_block cpuidle_latency_notifier = { | |
550 | .notifier_call = cpuidle_latency_notify, | |
551 | }; | |
552 | ||
d82b3518 MG |
553 | static inline void latency_notifier_init(struct notifier_block *n) |
554 | { | |
555 | pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n); | |
556 | } | |
4f86d3a8 LB |
557 | |
558 | #else /* CONFIG_SMP */ | |
559 | ||
560 | #define latency_notifier_init(x) do { } while (0) | |
561 | ||
562 | #endif /* CONFIG_SMP */ | |
563 | ||
564 | /** | |
565 | * cpuidle_init - core initializer | |
566 | */ | |
567 | static int __init cpuidle_init(void) | |
568 | { | |
569 | int ret; | |
570 | ||
62027aea LB |
571 | if (cpuidle_disabled()) |
572 | return -ENODEV; | |
573 | ||
8a25a2fd | 574 | ret = cpuidle_add_interface(cpu_subsys.dev_root); |
4f86d3a8 LB |
575 | if (ret) |
576 | return ret; | |
577 | ||
578 | latency_notifier_init(&cpuidle_latency_notifier); | |
579 | ||
580 | return 0; | |
581 | } | |
582 | ||
62027aea | 583 | module_param(off, int, 0444); |
4f86d3a8 | 584 | core_initcall(cpuidle_init); |