blob: e28f6ea46f1a0c31062890450c79b13f896a337b [file] [log] [blame]
Len Brown4f86d3a2007-10-03 18:58:00 -04001/*
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
11#include <linux/kernel.h>
12#include <linux/mutex.h>
13#include <linux/sched.h>
14#include <linux/notifier.h>
Jean Pihete8db0be2011-08-25 15:35:03 +020015#include <linux/pm_qos.h>
Len Brown4f86d3a2007-10-03 18:58:00 -040016#include <linux/cpu.h>
17#include <linux/cpuidle.h>
venkatesh.pallipadi@intel.com9a0b8412008-01-31 17:35:06 -080018#include <linux/ktime.h>
Arjan van de Ven2e94d1f2008-09-10 16:06:00 -070019#include <linux/hrtimer.h>
Paul Gortmaker884b17e2011-08-29 17:52:39 -040020#include <linux/module.h>
Arjan van de Ven288f0232009-09-19 13:35:33 +020021#include <trace/events/power.h>
Len Brown4f86d3a2007-10-03 18:58:00 -040022
23#include "cpuidle.h"
24
25DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
Len Brown4f86d3a2007-10-03 18:58:00 -040026
27DEFINE_MUTEX(cpuidle_lock);
28LIST_HEAD(cpuidle_detected_devices);
Len Brown4f86d3a2007-10-03 18:58:00 -040029
30static int enabled_devices;
Len Brown62027ae2011-04-01 18:13:10 -040031static int off __read_mostly;
Len Browna0bfa132011-04-01 19:34:59 -040032static int initialized __read_mostly;
Len Brown62027ae2011-04-01 18:13:10 -040033
34int cpuidle_disabled(void)
35{
36 return off;
37}
Len Brownd91ee582011-04-01 18:28:35 -040038void disable_cpuidle(void)
39{
40 off = 1;
41}
Len Brown4f86d3a2007-10-03 18:58:00 -040042
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -040043static int __cpuidle_register_device(struct cpuidle_device *dev);
44
Robert Leee1689792012-03-20 15:22:42 -050045static inline int cpuidle_enter(struct cpuidle_device *dev,
46 struct cpuidle_driver *drv, int index)
47{
48 struct cpuidle_state *target_state = &drv->states[index];
49 return target_state->enter(dev, drv, index);
50}
51
52static inline int cpuidle_enter_tk(struct cpuidle_device *dev,
53 struct cpuidle_driver *drv, int index)
54{
55 return cpuidle_wrap_enter(dev, drv, index, cpuidle_enter);
56}
57
58typedef int (*cpuidle_enter_t)(struct cpuidle_device *dev,
59 struct cpuidle_driver *drv, int index);
60
61static cpuidle_enter_t cpuidle_enter_ops;
62
Len Brown4f86d3a2007-10-03 18:58:00 -040063/**
Boris Ostrovsky1a022e32012-03-13 19:55:09 +010064 * cpuidle_play_dead - cpu off-lining
65 *
Toshi Kaniee01e662012-03-31 21:37:02 -060066 * Returns in case of an error or no driver
Boris Ostrovsky1a022e32012-03-13 19:55:09 +010067 */
68int cpuidle_play_dead(void)
69{
70 struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
71 struct cpuidle_driver *drv = cpuidle_get_driver();
72 int i, dead_state = -1;
73 int power_usage = -1;
74
Toshi Kaniee01e662012-03-31 21:37:02 -060075 if (!drv)
76 return -ENODEV;
77
Boris Ostrovsky1a022e32012-03-13 19:55:09 +010078 /* Find lowest-power state that supports long-term idle */
79 for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
80 struct cpuidle_state *s = &drv->states[i];
81
82 if (s->power_usage < power_usage && s->enter_dead) {
83 power_usage = s->power_usage;
84 dead_state = i;
85 }
86 }
87
88 if (dead_state != -1)
89 return drv->states[dead_state].enter_dead(dev, dead_state);
90
91 return -ENODEV;
92}
93
94/**
Colin Cross56cfbf72012-05-07 17:57:39 -070095 * cpuidle_enter_state - enter the state and update stats
96 * @dev: cpuidle device for this cpu
97 * @drv: cpuidle driver for this cpu
98 * @next_state: index into drv->states of the state to enter
99 */
100int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
101 int next_state)
102{
103 int entered_state;
104
105 entered_state = cpuidle_enter_ops(dev, drv, next_state);
106
107 if (entered_state >= 0) {
108 /* Update cpuidle counters */
109 /* This can be moved to within driver enter routine
110 * but that results in multiple copies of same code.
111 */
112 dev->states_usage[entered_state].time +=
113 (unsigned long long)dev->last_residency;
114 dev->states_usage[entered_state].usage++;
115 } else {
116 dev->last_residency = 0;
117 }
118
119 return entered_state;
120}
121
122/**
Len Brown4f86d3a2007-10-03 18:58:00 -0400123 * cpuidle_idle_call - the main idle loop
124 *
125 * NOTE: no locks or semaphores should be used here
Len Browna0bfa132011-04-01 19:34:59 -0400126 * return non-zero on failure
Len Brown4f86d3a2007-10-03 18:58:00 -0400127 */
Len Browna0bfa132011-04-01 19:34:59 -0400128int cpuidle_idle_call(void)
Len Brown4f86d3a2007-10-03 18:58:00 -0400129{
Christoph Lameter4a6f4fe2010-12-06 11:16:24 -0600130 struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
Deepthi Dharwar46bcfad2011-10-28 16:20:42 +0530131 struct cpuidle_driver *drv = cpuidle_get_driver();
Deepthi Dharware978aa72011-10-28 16:20:09 +0530132 int next_state, entered_state;
Len Brown4f86d3a2007-10-03 18:58:00 -0400133
Len Browna0bfa132011-04-01 19:34:59 -0400134 if (off)
135 return -ENODEV;
136
137 if (!initialized)
138 return -ENODEV;
139
Len Brown4f86d3a2007-10-03 18:58:00 -0400140 /* check if the device is ready */
Len Browna0bfa132011-04-01 19:34:59 -0400141 if (!dev || !dev->enabled)
142 return -EBUSY;
Len Brown4f86d3a2007-10-03 18:58:00 -0400143
144 /* ask the governor for the next state */
Deepthi Dharwar46bcfad2011-10-28 16:20:42 +0530145 next_state = cpuidle_curr_governor->select(drv, dev);
Kevin Hilman246eb7f2009-10-26 16:50:18 -0700146 if (need_resched()) {
147 local_irq_enable();
Len Browna0bfa132011-04-01 19:34:59 -0400148 return 0;
Kevin Hilman246eb7f2009-10-26 16:50:18 -0700149 }
150
Steven Rostedt76027ea2012-02-07 09:46:01 -0500151 trace_power_start_rcuidle(POWER_CSTATE, next_state, dev->cpu);
152 trace_cpu_idle_rcuidle(next_state, dev->cpu);
Thomas Renningerf77cfe42011-01-07 11:29:44 +0100153
Colin Cross4126c012012-05-07 17:57:41 -0700154 if (cpuidle_state_is_coupled(dev, drv, next_state))
155 entered_state = cpuidle_enter_state_coupled(dev, drv,
156 next_state);
157 else
158 entered_state = cpuidle_enter_state(dev, drv, next_state);
Thomas Renningerf77cfe42011-01-07 11:29:44 +0100159
Steven Rostedt76027ea2012-02-07 09:46:01 -0500160 trace_power_end_rcuidle(dev->cpu);
161 trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
Thomas Renningerf77cfe42011-01-07 11:29:44 +0100162
Len Brown4f86d3a2007-10-03 18:58:00 -0400163 /* give the governor an opportunity to reflect on the outcome */
164 if (cpuidle_curr_governor->reflect)
Deepthi Dharware978aa72011-10-28 16:20:09 +0530165 cpuidle_curr_governor->reflect(dev, entered_state);
Len Browna0bfa132011-04-01 19:34:59 -0400166
167 return 0;
Len Brown4f86d3a2007-10-03 18:58:00 -0400168}
169
170/**
171 * cpuidle_install_idle_handler - installs the cpuidle idle loop handler
172 */
173void cpuidle_install_idle_handler(void)
174{
Len Browna0bfa132011-04-01 19:34:59 -0400175 if (enabled_devices) {
Len Brown4f86d3a2007-10-03 18:58:00 -0400176 /* Make sure all changes finished before we switch to new idle */
177 smp_wmb();
Len Browna0bfa132011-04-01 19:34:59 -0400178 initialized = 1;
Len Brown4f86d3a2007-10-03 18:58:00 -0400179 }
180}
181
182/**
183 * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
184 */
185void cpuidle_uninstall_idle_handler(void)
186{
Len Browna0bfa132011-04-01 19:34:59 -0400187 if (enabled_devices) {
188 initialized = 0;
Thomas Gleixner4a162512012-05-07 17:59:48 +0000189 kick_all_cpus_sync();
Len Brown4f86d3a2007-10-03 18:58:00 -0400190 }
191}
192
193/**
194 * cpuidle_pause_and_lock - temporarily disables CPUIDLE
195 */
196void cpuidle_pause_and_lock(void)
197{
198 mutex_lock(&cpuidle_lock);
199 cpuidle_uninstall_idle_handler();
200}
201
202EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);
203
204/**
205 * cpuidle_resume_and_unlock - resumes CPUIDLE operation
206 */
207void cpuidle_resume_and_unlock(void)
208{
209 cpuidle_install_idle_handler();
210 mutex_unlock(&cpuidle_lock);
211}
212
213EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);
214
Preeti U Murthy8651f972012-07-09 10:12:56 +0200215/* Currently used in suspend/resume path to suspend cpuidle */
216void cpuidle_pause(void)
217{
218 mutex_lock(&cpuidle_lock);
219 cpuidle_uninstall_idle_handler();
220 mutex_unlock(&cpuidle_lock);
221}
222
223/* Currently used in suspend/resume path to resume cpuidle */
224void cpuidle_resume(void)
225{
226 mutex_lock(&cpuidle_lock);
227 cpuidle_install_idle_handler();
228 mutex_unlock(&cpuidle_lock);
229}
230
Robert Leee1689792012-03-20 15:22:42 -0500231/**
232 * cpuidle_wrap_enter - performs timekeeping and irqen around enter function
233 * @dev: pointer to a valid cpuidle_device object
234 * @drv: pointer to a valid cpuidle_driver object
235 * @index: index of the target cpuidle state.
236 */
237int cpuidle_wrap_enter(struct cpuidle_device *dev,
238 struct cpuidle_driver *drv, int index,
239 int (*enter)(struct cpuidle_device *dev,
240 struct cpuidle_driver *drv, int index))
241{
242 ktime_t time_start, time_end;
243 s64 diff;
244
245 time_start = ktime_get();
246
247 index = enter(dev, drv, index);
248
249 time_end = ktime_get();
250
251 local_irq_enable();
252
253 diff = ktime_to_us(ktime_sub(time_end, time_start));
254 if (diff > INT_MAX)
255 diff = INT_MAX;
256
257 dev->last_residency = (int) diff;
258
259 return index;
260}
261
Rafael J. Wysockid8c216c2011-01-08 00:29:20 +0100262#ifdef CONFIG_ARCH_HAS_CPU_RELAX
Deepthi Dharwar46bcfad2011-10-28 16:20:42 +0530263static int poll_idle(struct cpuidle_device *dev,
264 struct cpuidle_driver *drv, int index)
Rafael J. Wysockid8c216c2011-01-08 00:29:20 +0100265{
266 ktime_t t1, t2;
267 s64 diff;
Rafael J. Wysockid8c216c2011-01-08 00:29:20 +0100268
269 t1 = ktime_get();
270 local_irq_enable();
271 while (!need_resched())
272 cpu_relax();
273
274 t2 = ktime_get();
275 diff = ktime_to_us(ktime_sub(t2, t1));
276 if (diff > INT_MAX)
277 diff = INT_MAX;
278
Deepthi Dharware978aa72011-10-28 16:20:09 +0530279 dev->last_residency = (int) diff;
280
281 return index;
Rafael J. Wysockid8c216c2011-01-08 00:29:20 +0100282}
283
Deepthi Dharwar46bcfad2011-10-28 16:20:42 +0530284static void poll_idle_init(struct cpuidle_driver *drv)
Rafael J. Wysockid8c216c2011-01-08 00:29:20 +0100285{
Deepthi Dharwar46bcfad2011-10-28 16:20:42 +0530286 struct cpuidle_state *state = &drv->states[0];
Rafael J. Wysockid8c216c2011-01-08 00:29:20 +0100287
Thomas Renninger720f1c32011-01-07 11:29:43 +0100288 snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
Rafael J. Wysockid8c216c2011-01-08 00:29:20 +0100289 snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
290 state->exit_latency = 0;
291 state->target_residency = 0;
292 state->power_usage = -1;
Len Brownd2476322011-01-12 02:34:59 -0500293 state->flags = 0;
Rafael J. Wysockid8c216c2011-01-08 00:29:20 +0100294 state->enter = poll_idle;
Rafael J. Wysockicbc9ef02012-07-03 19:07:42 +0200295 state->disabled = false;
Rafael J. Wysockid8c216c2011-01-08 00:29:20 +0100296}
297#else
Deepthi Dharwar46bcfad2011-10-28 16:20:42 +0530298static void poll_idle_init(struct cpuidle_driver *drv) {}
Rafael J. Wysockid8c216c2011-01-08 00:29:20 +0100299#endif /* CONFIG_ARCH_HAS_CPU_RELAX */
300
Len Brown4f86d3a2007-10-03 18:58:00 -0400301/**
302 * cpuidle_enable_device - enables idle PM for a CPU
303 * @dev: the CPU
304 *
305 * This function must be called between cpuidle_pause_and_lock and
306 * cpuidle_resume_and_unlock when used externally.
307 */
308int cpuidle_enable_device(struct cpuidle_device *dev)
309{
310 int ret, i;
Robert Leee1689792012-03-20 15:22:42 -0500311 struct cpuidle_driver *drv = cpuidle_get_driver();
Len Brown4f86d3a2007-10-03 18:58:00 -0400312
Srivatsa S. Bhat1b0a0e92012-05-04 14:06:02 -0700313 if (!dev)
314 return -EINVAL;
315
Len Brown4f86d3a2007-10-03 18:58:00 -0400316 if (dev->enabled)
317 return 0;
Robert Leee1689792012-03-20 15:22:42 -0500318 if (!drv || !cpuidle_curr_governor)
Len Brown4f86d3a2007-10-03 18:58:00 -0400319 return -EIO;
320 if (!dev->state_count)
Daniel Lezcanofc850f32012-03-26 14:51:26 +0200321 dev->state_count = drv->state_count;
Len Brown4f86d3a2007-10-03 18:58:00 -0400322
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -0400323 if (dev->registered == 0) {
324 ret = __cpuidle_register_device(dev);
325 if (ret)
326 return ret;
327 }
328
Robert Leee1689792012-03-20 15:22:42 -0500329 cpuidle_enter_ops = drv->en_core_tk_irqen ?
330 cpuidle_enter_tk : cpuidle_enter;
331
332 poll_idle_init(drv);
Rafael J. Wysockid8c216c2011-01-08 00:29:20 +0100333
Len Brown4f86d3a2007-10-03 18:58:00 -0400334 if ((ret = cpuidle_add_state_sysfs(dev)))
335 return ret;
336
337 if (cpuidle_curr_governor->enable &&
Robert Leee1689792012-03-20 15:22:42 -0500338 (ret = cpuidle_curr_governor->enable(drv, dev)))
Len Brown4f86d3a2007-10-03 18:58:00 -0400339 goto fail_sysfs;
340
341 for (i = 0; i < dev->state_count; i++) {
Deepthi Dharwar42027352011-10-28 16:20:33 +0530342 dev->states_usage[i].usage = 0;
343 dev->states_usage[i].time = 0;
Len Brown4f86d3a2007-10-03 18:58:00 -0400344 }
345 dev->last_residency = 0;
Len Brown4f86d3a2007-10-03 18:58:00 -0400346
347 smp_wmb();
348
349 dev->enabled = 1;
350
351 enabled_devices++;
352 return 0;
353
354fail_sysfs:
355 cpuidle_remove_state_sysfs(dev);
356
357 return ret;
358}
359
360EXPORT_SYMBOL_GPL(cpuidle_enable_device);
361
362/**
363 * cpuidle_disable_device - disables idle PM for a CPU
364 * @dev: the CPU
365 *
366 * This function must be called between cpuidle_pause_and_lock and
367 * cpuidle_resume_and_unlock when used externally.
368 */
369void cpuidle_disable_device(struct cpuidle_device *dev)
370{
371 if (!dev->enabled)
372 return;
Len Brown752138d2010-05-22 16:57:26 -0400373 if (!cpuidle_get_driver() || !cpuidle_curr_governor)
Len Brown4f86d3a2007-10-03 18:58:00 -0400374 return;
375
376 dev->enabled = 0;
377
378 if (cpuidle_curr_governor->disable)
Deepthi Dharwar46bcfad2011-10-28 16:20:42 +0530379 cpuidle_curr_governor->disable(cpuidle_get_driver(), dev);
Len Brown4f86d3a2007-10-03 18:58:00 -0400380
381 cpuidle_remove_state_sysfs(dev);
382 enabled_devices--;
383}
384
385EXPORT_SYMBOL_GPL(cpuidle_disable_device);
386
387/**
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -0400388 * __cpuidle_register_device - internal register function called before register
389 * and enable routines
Len Brown4f86d3a2007-10-03 18:58:00 -0400390 * @dev: the cpu
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -0400391 *
392 * cpuidle_lock mutex must be held before this is called
Len Brown4f86d3a2007-10-03 18:58:00 -0400393 */
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -0400394static int __cpuidle_register_device(struct cpuidle_device *dev)
Len Brown4f86d3a2007-10-03 18:58:00 -0400395{
396 int ret;
Kay Sievers8a25a2f2011-12-21 14:29:42 -0800397 struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu);
Len Brown752138d2010-05-22 16:57:26 -0400398 struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
Len Brown4f86d3a2007-10-03 18:58:00 -0400399
Len Brown752138d2010-05-22 16:57:26 -0400400 if (!try_module_get(cpuidle_driver->owner))
Len Brown4f86d3a2007-10-03 18:58:00 -0400401 return -EINVAL;
402
403 init_completion(&dev->kobj_unregister);
404
Len Brown4f86d3a2007-10-03 18:58:00 -0400405 per_cpu(cpuidle_devices, dev->cpu) = dev;
406 list_add(&dev->device_list, &cpuidle_detected_devices);
Colin Cross3af272a2012-05-07 17:57:40 -0700407 ret = cpuidle_add_sysfs(cpu_dev);
408 if (ret)
409 goto err_sysfs;
Len Brown4f86d3a2007-10-03 18:58:00 -0400410
Colin Cross4126c012012-05-07 17:57:41 -0700411 ret = cpuidle_coupled_register_device(dev);
412 if (ret)
413 goto err_coupled;
Len Brown4f86d3a2007-10-03 18:58:00 -0400414
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -0400415 dev->registered = 1;
416 return 0;
Colin Cross3af272a2012-05-07 17:57:40 -0700417
Colin Cross4126c012012-05-07 17:57:41 -0700418err_coupled:
419 cpuidle_remove_sysfs(cpu_dev);
420 wait_for_completion(&dev->kobj_unregister);
Colin Cross3af272a2012-05-07 17:57:40 -0700421err_sysfs:
422 list_del(&dev->device_list);
423 per_cpu(cpuidle_devices, dev->cpu) = NULL;
424 module_put(cpuidle_driver->owner);
425 return ret;
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -0400426}
427
428/**
429 * cpuidle_register_device - registers a CPU's idle PM feature
430 * @dev: the cpu
431 */
432int cpuidle_register_device(struct cpuidle_device *dev)
433{
434 int ret;
435
Srivatsa S. Bhat1b0a0e92012-05-04 14:06:02 -0700436 if (!dev)
437 return -EINVAL;
438
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -0400439 mutex_lock(&cpuidle_lock);
440
441 if ((ret = __cpuidle_register_device(dev))) {
442 mutex_unlock(&cpuidle_lock);
443 return ret;
444 }
445
Len Brown4f86d3a2007-10-03 18:58:00 -0400446 cpuidle_enable_device(dev);
447 cpuidle_install_idle_handler();
448
449 mutex_unlock(&cpuidle_lock);
450
451 return 0;
452
453}
454
455EXPORT_SYMBOL_GPL(cpuidle_register_device);
456
457/**
458 * cpuidle_unregister_device - unregisters a CPU's idle PM feature
459 * @dev: the cpu
460 */
461void cpuidle_unregister_device(struct cpuidle_device *dev)
462{
Kay Sievers8a25a2f2011-12-21 14:29:42 -0800463 struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu);
Len Brown752138d2010-05-22 16:57:26 -0400464 struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
Len Brown4f86d3a2007-10-03 18:58:00 -0400465
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -0400466 if (dev->registered == 0)
467 return;
468
Len Brown4f86d3a2007-10-03 18:58:00 -0400469 cpuidle_pause_and_lock();
470
471 cpuidle_disable_device(dev);
472
Kay Sievers8a25a2f2011-12-21 14:29:42 -0800473 cpuidle_remove_sysfs(cpu_dev);
Len Brown4f86d3a2007-10-03 18:58:00 -0400474 list_del(&dev->device_list);
475 wait_for_completion(&dev->kobj_unregister);
476 per_cpu(cpuidle_devices, dev->cpu) = NULL;
477
Colin Cross4126c012012-05-07 17:57:41 -0700478 cpuidle_coupled_unregister_device(dev);
479
Len Brown4f86d3a2007-10-03 18:58:00 -0400480 cpuidle_resume_and_unlock();
481
Len Brown752138d2010-05-22 16:57:26 -0400482 module_put(cpuidle_driver->owner);
Len Brown4f86d3a2007-10-03 18:58:00 -0400483}
484
485EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
486
487#ifdef CONFIG_SMP
488
489static void smp_callback(void *v)
490{
491 /* we already woke the CPU up, nothing more to do */
492}
493
494/*
495 * This function gets called when a part of the kernel has a new latency
496 * requirement. This means we need to get all processors out of their C-state,
497 * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
498 * wakes them all right up.
499 */
500static int cpuidle_latency_notify(struct notifier_block *b,
501 unsigned long l, void *v)
502{
Jens Axboe8691e5a2008-06-06 11:18:06 +0200503 smp_call_function(smp_callback, NULL, 1);
Len Brown4f86d3a2007-10-03 18:58:00 -0400504 return NOTIFY_OK;
505}
506
507static struct notifier_block cpuidle_latency_notifier = {
508 .notifier_call = cpuidle_latency_notify,
509};
510
Mark Grossd82b3512008-02-04 22:30:08 -0800511static inline void latency_notifier_init(struct notifier_block *n)
512{
513 pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
514}
Len Brown4f86d3a2007-10-03 18:58:00 -0400515
516#else /* CONFIG_SMP */
517
518#define latency_notifier_init(x) do { } while (0)
519
520#endif /* CONFIG_SMP */
521
522/**
523 * cpuidle_init - core initializer
524 */
525static int __init cpuidle_init(void)
526{
527 int ret;
528
Len Brown62027ae2011-04-01 18:13:10 -0400529 if (cpuidle_disabled())
530 return -ENODEV;
531
Kay Sievers8a25a2f2011-12-21 14:29:42 -0800532 ret = cpuidle_add_interface(cpu_subsys.dev_root);
Len Brown4f86d3a2007-10-03 18:58:00 -0400533 if (ret)
534 return ret;
535
536 latency_notifier_init(&cpuidle_latency_notifier);
537
538 return 0;
539}
540
Len Brown62027ae2011-04-01 18:13:10 -0400541module_param(off, int, 0444);
Len Brown4f86d3a2007-10-03 18:58:00 -0400542core_initcall(cpuidle_init);