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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
Daniel Lezcanob60e6a02013-03-21 12:21:31 +000011#include <linux/clockchips.h>
Len Brown4f86d3a2007-10-03 18:58:00 -040012#include <linux/kernel.h>
13#include <linux/mutex.h>
14#include <linux/sched.h>
15#include <linux/notifier.h>
Jean Pihete8db0be2011-08-25 15:35:03 +020016#include <linux/pm_qos.h>
Len Brown4f86d3a2007-10-03 18:58:00 -040017#include <linux/cpu.h>
18#include <linux/cpuidle.h>
venkatesh.pallipadi@intel.com9a0b8412008-01-31 17:35:06 -080019#include <linux/ktime.h>
Arjan van de Ven2e94d1f2008-09-10 16:06:00 -070020#include <linux/hrtimer.h>
Paul Gortmaker884b17e2011-08-29 17:52:39 -040021#include <linux/module.h>
Rafael J. Wysocki38106312015-02-12 23:33:15 +010022#include <linux/suspend.h>
Rafael J. Wysocki124cf9112015-02-13 23:50:43 +010023#include <linux/tick.h>
Arjan van de Ven288f0232009-09-19 13:35:33 +020024#include <trace/events/power.h>
Len Brown4f86d3a2007-10-03 18:58:00 -040025
26#include "cpuidle.h"
27
28DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
Daniel Lezcano4c637b22013-04-23 08:54:33 +000029DEFINE_PER_CPU(struct cpuidle_device, cpuidle_dev);
Len Brown4f86d3a2007-10-03 18:58:00 -040030
31DEFINE_MUTEX(cpuidle_lock);
32LIST_HEAD(cpuidle_detected_devices);
Len Brown4f86d3a2007-10-03 18:58:00 -040033
34static int enabled_devices;
Len Brown62027ae2011-04-01 18:13:10 -040035static int off __read_mostly;
Len Browna0bfa132011-04-01 19:34:59 -040036static int initialized __read_mostly;
Len Brown62027ae2011-04-01 18:13:10 -040037
38int cpuidle_disabled(void)
39{
40 return off;
41}
Len Brownd91ee582011-04-01 18:28:35 -040042void disable_cpuidle(void)
43{
44 off = 1;
45}
Len Brown4f86d3a2007-10-03 18:58:00 -040046
Rafael J. Wysockief2b22a2015-03-02 22:26:55 +010047bool cpuidle_not_available(struct cpuidle_driver *drv,
48 struct cpuidle_device *dev)
Rafael J. Wysocki31a34092015-02-27 00:39:56 +010049{
50 return off || !initialized || !drv || !dev || !dev->enabled;
51}
52
Len Brown4f86d3a2007-10-03 18:58:00 -040053/**
Boris Ostrovsky1a022e32012-03-13 19:55:09 +010054 * cpuidle_play_dead - cpu off-lining
55 *
Toshi Kaniee01e662012-03-31 21:37:02 -060056 * Returns in case of an error or no driver
Boris Ostrovsky1a022e32012-03-13 19:55:09 +010057 */
58int cpuidle_play_dead(void)
59{
60 struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +000061 struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
Daniel Lezcano8aef33a2013-01-15 14:18:04 +010062 int i;
Boris Ostrovsky1a022e32012-03-13 19:55:09 +010063
Toshi Kaniee01e662012-03-31 21:37:02 -060064 if (!drv)
65 return -ENODEV;
66
Boris Ostrovsky1a022e32012-03-13 19:55:09 +010067 /* Find lowest-power state that supports long-term idle */
Rafael J. Wysocki7d51d9792015-05-28 04:09:24 +020068 for (i = drv->state_count - 1; i >= 0; i--)
Daniel Lezcano8aef33a2013-01-15 14:18:04 +010069 if (drv->states[i].enter_dead)
70 return drv->states[i].enter_dead(dev, i);
Boris Ostrovsky1a022e32012-03-13 19:55:09 +010071
72 return -ENODEV;
73}
74
Rafael J. Wysockief2b22a2015-03-02 22:26:55 +010075static int find_deepest_state(struct cpuidle_driver *drv,
Rafael J. Wysocki0d940392015-05-10 01:19:52 +020076 struct cpuidle_device *dev,
77 unsigned int max_latency,
78 unsigned int forbidden_flags,
79 bool freeze)
Rafael J. Wysockia6220fc2014-05-05 00:51:54 +020080{
81 unsigned int latency_req = 0;
Rafael J. Wysocki7d51d9792015-05-28 04:09:24 +020082 int i, ret = -ENXIO;
Rafael J. Wysockia6220fc2014-05-05 00:51:54 +020083
Rafael J. Wysocki7d51d9792015-05-28 04:09:24 +020084 for (i = 0; i < drv->state_count; i++) {
Rafael J. Wysockia6220fc2014-05-05 00:51:54 +020085 struct cpuidle_state *s = &drv->states[i];
86 struct cpuidle_state_usage *su = &dev->states_usage[i];
87
Rafael J. Wysocki124cf9112015-02-13 23:50:43 +010088 if (s->disabled || su->disable || s->exit_latency <= latency_req
Rafael J. Wysocki0d940392015-05-10 01:19:52 +020089 || s->exit_latency > max_latency
90 || (s->flags & forbidden_flags)
Rafael J. Wysocki124cf9112015-02-13 23:50:43 +010091 || (freeze && !s->enter_freeze))
Rafael J. Wysockia6220fc2014-05-05 00:51:54 +020092 continue;
93
94 latency_req = s->exit_latency;
95 ret = i;
96 }
97 return ret;
98}
99
Rafael J. Wysocki87e9b9f2015-05-16 01:38:15 +0200100#ifdef CONFIG_SUSPEND
Rafael J. Wysockief2b22a2015-03-02 22:26:55 +0100101/**
102 * cpuidle_find_deepest_state - Find the deepest available idle state.
103 * @drv: cpuidle driver for the given CPU.
104 * @dev: cpuidle device for the given CPU.
105 */
106int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
107 struct cpuidle_device *dev)
108{
Rafael J. Wysocki0d940392015-05-10 01:19:52 +0200109 return find_deepest_state(drv, dev, UINT_MAX, 0, false);
Rafael J. Wysockief2b22a2015-03-02 22:26:55 +0100110}
111
Rafael J. Wysocki124cf9112015-02-13 23:50:43 +0100112static void enter_freeze_proper(struct cpuidle_driver *drv,
113 struct cpuidle_device *dev, int index)
114{
Rafael J. Wysockiae0afb42015-07-09 22:59:49 +0200115 /*
116 * trace_suspend_resume() called by tick_freeze() for the last CPU
117 * executing it contains RCU usage regarded as invalid in the idle
118 * context, so tell RCU about that.
119 */
120 RCU_NONIDLE(tick_freeze());
Rafael J. Wysocki124cf9112015-02-13 23:50:43 +0100121 /*
122 * The state used here cannot be a "coupled" one, because the "coupled"
123 * cpuidle mechanism enables interrupts and doing that with timekeeping
124 * suspended is generally unsafe.
125 */
126 drv->states[index].enter_freeze(dev, drv, index);
127 WARN_ON(!irqs_disabled());
128 /*
129 * timekeeping_resume() that will be called by tick_unfreeze() for the
Rafael J. Wysockiae0afb42015-07-09 22:59:49 +0200130 * first CPU executing it calls functions containing RCU read-side
Rafael J. Wysocki124cf9112015-02-13 23:50:43 +0100131 * critical sections, so tell RCU about that.
132 */
133 RCU_NONIDLE(tick_unfreeze());
134}
135
Rafael J. Wysockia6220fc2014-05-05 00:51:54 +0200136/**
Rafael J. Wysocki38106312015-02-12 23:33:15 +0100137 * cpuidle_enter_freeze - Enter an idle state suitable for suspend-to-idle.
Rafael J. Wysockief2b22a2015-03-02 22:26:55 +0100138 * @drv: cpuidle driver for the given CPU.
139 * @dev: cpuidle device for the given CPU.
Rafael J. Wysocki38106312015-02-12 23:33:15 +0100140 *
Rafael J. Wysocki124cf9112015-02-13 23:50:43 +0100141 * If there are states with the ->enter_freeze callback, find the deepest of
Rafael J. Wysockief2b22a2015-03-02 22:26:55 +0100142 * them and enter it with frozen tick.
Rafael J. Wysocki38106312015-02-12 23:33:15 +0100143 */
Rafael J. Wysockief2b22a2015-03-02 22:26:55 +0100144int cpuidle_enter_freeze(struct cpuidle_driver *drv, struct cpuidle_device *dev)
Rafael J. Wysocki38106312015-02-12 23:33:15 +0100145{
Rafael J. Wysocki38106312015-02-12 23:33:15 +0100146 int index;
147
Rafael J. Wysocki124cf9112015-02-13 23:50:43 +0100148 /*
149 * Find the deepest state with ->enter_freeze present, which guarantees
150 * that interrupts won't be enabled when it exits and allows the tick to
151 * be frozen safely.
152 */
Rafael J. Wysocki0d940392015-05-10 01:19:52 +0200153 index = find_deepest_state(drv, dev, UINT_MAX, 0, true);
Rafael J. Wysockief2b22a2015-03-02 22:26:55 +0100154 if (index >= 0)
Rafael J. Wysocki124cf9112015-02-13 23:50:43 +0100155 enter_freeze_proper(drv, dev, index);
Rafael J. Wysocki124cf9112015-02-13 23:50:43 +0100156
Rafael J. Wysockief2b22a2015-03-02 22:26:55 +0100157 return index;
Rafael J. Wysocki38106312015-02-12 23:33:15 +0100158}
Rafael J. Wysocki87e9b9f2015-05-16 01:38:15 +0200159#endif /* CONFIG_SUSPEND */
Rafael J. Wysocki38106312015-02-12 23:33:15 +0100160
161/**
Colin Cross56cfbf72012-05-07 17:57:39 -0700162 * cpuidle_enter_state - enter the state and update stats
163 * @dev: cpuidle device for this cpu
164 * @drv: cpuidle driver for this cpu
Rafael J. Wysocki73122802015-05-09 21:50:32 +0200165 * @index: index into the states table in @drv of the state to enter
Colin Cross56cfbf72012-05-07 17:57:39 -0700166 */
167int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
Daniel Lezcano554c06b2013-04-23 08:54:31 +0000168 int index)
Colin Cross56cfbf72012-05-07 17:57:39 -0700169{
170 int entered_state;
171
Daniel Lezcano554c06b2013-04-23 08:54:31 +0000172 struct cpuidle_state *target_state = &drv->states[index];
Rafael J. Wysockidf8d9ee2015-04-29 15:19:21 +0200173 bool broadcast = !!(target_state->flags & CPUIDLE_FLAG_TIMER_STOP);
Daniel Lezcano554c06b2013-04-23 08:54:31 +0000174 ktime_t time_start, time_end;
175 s64 diff;
176
Rafael J. Wysockidf8d9ee2015-04-29 15:19:21 +0200177 /*
178 * Tell the time framework to switch to a broadcast timer because our
179 * local timer will be shut down. If a local timer is used from another
180 * CPU as a broadcast timer, this call may fail if it is not available.
181 */
Rafael J. Wysocki827a5ae2015-05-10 01:18:46 +0200182 if (broadcast && tick_broadcast_enter()) {
Rafael J. Wysocki0d940392015-05-10 01:19:52 +0200183 index = find_deepest_state(drv, dev, target_state->exit_latency,
184 CPUIDLE_FLAG_TIMER_STOP, false);
185 if (index < 0) {
186 default_idle_call();
187 return -EBUSY;
188 }
189 target_state = &drv->states[index];
Rafael J. Wysocki827a5ae2015-05-10 01:18:46 +0200190 }
Rafael J. Wysockidf8d9ee2015-04-29 15:19:21 +0200191
Rafael J. Wysockifaad3842015-05-10 01:18:03 +0200192 /* Take note of the planned idle state. */
193 sched_idle_set_state(target_state);
194
Sandeep Tripathy30fe6882014-07-02 15:00:58 +0530195 trace_cpu_idle_rcuidle(index, dev->cpu);
Daniel Lezcano554c06b2013-04-23 08:54:31 +0000196 time_start = ktime_get();
197
198 entered_state = target_state->enter(dev, drv, index);
199
200 time_end = ktime_get();
Sandeep Tripathy30fe6882014-07-02 15:00:58 +0530201 trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
Daniel Lezcano554c06b2013-04-23 08:54:31 +0000202
Rafael J. Wysockifaad3842015-05-10 01:18:03 +0200203 /* The cpu is no longer idle or about to enter idle. */
204 sched_idle_set_state(NULL);
205
Rafael J. Wysockidf8d9ee2015-04-29 15:19:21 +0200206 if (broadcast) {
207 if (WARN_ON_ONCE(!irqs_disabled()))
208 local_irq_disable();
209
210 tick_broadcast_exit();
211 }
212
Paul Burton0b89e9a2014-03-06 11:02:01 +0000213 if (!cpuidle_state_is_coupled(dev, drv, entered_state))
214 local_irq_enable();
Daniel Lezcano554c06b2013-04-23 08:54:31 +0000215
216 diff = ktime_to_us(ktime_sub(time_end, time_start));
217 if (diff > INT_MAX)
218 diff = INT_MAX;
219
220 dev->last_residency = (int) diff;
Colin Cross56cfbf72012-05-07 17:57:39 -0700221
222 if (entered_state >= 0) {
223 /* Update cpuidle counters */
224 /* This can be moved to within driver enter routine
225 * but that results in multiple copies of same code.
226 */
Julius Wernera474a512012-11-27 14:17:58 +0100227 dev->states_usage[entered_state].time += dev->last_residency;
Colin Cross56cfbf72012-05-07 17:57:39 -0700228 dev->states_usage[entered_state].usage++;
229 } else {
230 dev->last_residency = 0;
231 }
232
233 return entered_state;
234}
235
236/**
Daniel Lezcano907e30f2014-03-03 08:48:50 +0100237 * cpuidle_select - ask the cpuidle framework to choose an idle state
Len Brown4f86d3a2007-10-03 18:58:00 -0400238 *
Daniel Lezcano907e30f2014-03-03 08:48:50 +0100239 * @drv: the cpuidle driver
240 * @dev: the cpuidle device
241 *
242 * Returns the index of the idle state.
Len Brown4f86d3a2007-10-03 18:58:00 -0400243 */
Daniel Lezcano907e30f2014-03-03 08:48:50 +0100244int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
Len Brown4f86d3a2007-10-03 18:58:00 -0400245{
Daniel Lezcano907e30f2014-03-03 08:48:50 +0100246 return cpuidle_curr_governor->select(drv, dev);
247}
Len Brown4f86d3a2007-10-03 18:58:00 -0400248
Daniel Lezcano907e30f2014-03-03 08:48:50 +0100249/**
250 * cpuidle_enter - enter into the specified idle state
251 *
252 * @drv: the cpuidle driver tied with the cpu
253 * @dev: the cpuidle device
254 * @index: the index in the idle state table
255 *
256 * Returns the index in the idle state, < 0 in case of error.
257 * The error code depends on the backend driver
258 */
259int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev,
260 int index)
261{
262 if (cpuidle_state_is_coupled(dev, drv, index))
263 return cpuidle_enter_state_coupled(dev, drv, index);
264 return cpuidle_enter_state(dev, drv, index);
265}
Len Browna0bfa132011-04-01 19:34:59 -0400266
Daniel Lezcano907e30f2014-03-03 08:48:50 +0100267/**
268 * cpuidle_reflect - tell the underlying governor what was the state
269 * we were in
270 *
271 * @dev : the cpuidle device
272 * @index: the index in the idle state table
273 *
274 */
275void cpuidle_reflect(struct cpuidle_device *dev, int index)
276{
Rafael J. Wysockia802ea92015-05-04 22:53:28 +0200277 if (cpuidle_curr_governor->reflect && index >= 0)
Daniel Lezcano907e30f2014-03-03 08:48:50 +0100278 cpuidle_curr_governor->reflect(dev, index);
Len Brown4f86d3a2007-10-03 18:58:00 -0400279}
280
281/**
282 * cpuidle_install_idle_handler - installs the cpuidle idle loop handler
283 */
284void cpuidle_install_idle_handler(void)
285{
Len Browna0bfa132011-04-01 19:34:59 -0400286 if (enabled_devices) {
Len Brown4f86d3a2007-10-03 18:58:00 -0400287 /* Make sure all changes finished before we switch to new idle */
288 smp_wmb();
Len Browna0bfa132011-04-01 19:34:59 -0400289 initialized = 1;
Len Brown4f86d3a2007-10-03 18:58:00 -0400290 }
291}
292
293/**
294 * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
295 */
296void cpuidle_uninstall_idle_handler(void)
297{
Len Browna0bfa132011-04-01 19:34:59 -0400298 if (enabled_devices) {
299 initialized = 0;
Chuansheng Liu2ed903c2014-09-04 15:17:55 +0800300 wake_up_all_idle_cpus();
Len Brown4f86d3a2007-10-03 18:58:00 -0400301 }
Daniel Lezcano442bf3a2014-09-04 11:32:09 -0400302
303 /*
304 * Make sure external observers (such as the scheduler)
305 * are done looking at pointed idle states.
306 */
307 synchronize_rcu();
Len Brown4f86d3a2007-10-03 18:58:00 -0400308}
309
310/**
311 * cpuidle_pause_and_lock - temporarily disables CPUIDLE
312 */
313void cpuidle_pause_and_lock(void)
314{
315 mutex_lock(&cpuidle_lock);
316 cpuidle_uninstall_idle_handler();
317}
318
319EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);
320
321/**
322 * cpuidle_resume_and_unlock - resumes CPUIDLE operation
323 */
324void cpuidle_resume_and_unlock(void)
325{
326 cpuidle_install_idle_handler();
327 mutex_unlock(&cpuidle_lock);
328}
329
330EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);
331
Preeti U Murthy8651f972012-07-09 10:12:56 +0200332/* Currently used in suspend/resume path to suspend cpuidle */
333void cpuidle_pause(void)
334{
335 mutex_lock(&cpuidle_lock);
336 cpuidle_uninstall_idle_handler();
337 mutex_unlock(&cpuidle_lock);
338}
339
340/* Currently used in suspend/resume path to resume cpuidle */
341void cpuidle_resume(void)
342{
343 mutex_lock(&cpuidle_lock);
344 cpuidle_install_idle_handler();
345 mutex_unlock(&cpuidle_lock);
346}
347
Len Brown4f86d3a2007-10-03 18:58:00 -0400348/**
349 * cpuidle_enable_device - enables idle PM for a CPU
350 * @dev: the CPU
351 *
352 * This function must be called between cpuidle_pause_and_lock and
353 * cpuidle_resume_and_unlock when used externally.
354 */
355int cpuidle_enable_device(struct cpuidle_device *dev)
356{
Daniel Lezcano5df0aa72013-06-12 15:08:54 +0200357 int ret;
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000358 struct cpuidle_driver *drv;
Len Brown4f86d3a2007-10-03 18:58:00 -0400359
Srivatsa S. Bhat1b0a0e92012-05-04 14:06:02 -0700360 if (!dev)
361 return -EINVAL;
362
Len Brown4f86d3a2007-10-03 18:58:00 -0400363 if (dev->enabled)
364 return 0;
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000365
366 drv = cpuidle_get_cpu_driver(dev);
367
Robert Leee1689792012-03-20 15:22:42 -0500368 if (!drv || !cpuidle_curr_governor)
Len Brown4f86d3a2007-10-03 18:58:00 -0400369 return -EIO;
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000370
Daniel Lezcano10b9d3f2013-06-12 15:08:49 +0200371 if (!dev->registered)
372 return -EINVAL;
373
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000374 ret = cpuidle_add_device_sysfs(dev);
375 if (ret)
Len Brown4f86d3a2007-10-03 18:58:00 -0400376 return ret;
377
378 if (cpuidle_curr_governor->enable &&
Robert Leee1689792012-03-20 15:22:42 -0500379 (ret = cpuidle_curr_governor->enable(drv, dev)))
Len Brown4f86d3a2007-10-03 18:58:00 -0400380 goto fail_sysfs;
381
Len Brown4f86d3a2007-10-03 18:58:00 -0400382 smp_wmb();
383
384 dev->enabled = 1;
385
386 enabled_devices++;
387 return 0;
388
389fail_sysfs:
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000390 cpuidle_remove_device_sysfs(dev);
Len Brown4f86d3a2007-10-03 18:58:00 -0400391
392 return ret;
393}
394
395EXPORT_SYMBOL_GPL(cpuidle_enable_device);
396
397/**
398 * cpuidle_disable_device - disables idle PM for a CPU
399 * @dev: the CPU
400 *
401 * This function must be called between cpuidle_pause_and_lock and
402 * cpuidle_resume_and_unlock when used externally.
403 */
404void cpuidle_disable_device(struct cpuidle_device *dev)
405{
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000406 struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
407
Srivatsa S. Bhatcf31cd12012-10-08 13:43:08 +0530408 if (!dev || !dev->enabled)
Len Brown4f86d3a2007-10-03 18:58:00 -0400409 return;
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000410
411 if (!drv || !cpuidle_curr_governor)
Len Brown4f86d3a2007-10-03 18:58:00 -0400412 return;
413
414 dev->enabled = 0;
415
416 if (cpuidle_curr_governor->disable)
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000417 cpuidle_curr_governor->disable(drv, dev);
Len Brown4f86d3a2007-10-03 18:58:00 -0400418
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000419 cpuidle_remove_device_sysfs(dev);
Len Brown4f86d3a2007-10-03 18:58:00 -0400420 enabled_devices--;
421}
422
423EXPORT_SYMBOL_GPL(cpuidle_disable_device);
424
Daniel Lezcanof6bb51a2013-06-12 15:08:53 +0200425static void __cpuidle_unregister_device(struct cpuidle_device *dev)
426{
427 struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
428
429 list_del(&dev->device_list);
430 per_cpu(cpuidle_devices, dev->cpu) = NULL;
431 module_put(drv->owner);
432}
433
Viresh Kumar267d4bf2013-10-03 21:26:43 +0530434static void __cpuidle_device_init(struct cpuidle_device *dev)
Daniel Lezcano5df0aa72013-06-12 15:08:54 +0200435{
436 memset(dev->states_usage, 0, sizeof(dev->states_usage));
437 dev->last_residency = 0;
Daniel Lezcano5df0aa72013-06-12 15:08:54 +0200438}
439
Len Brown4f86d3a2007-10-03 18:58:00 -0400440/**
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -0400441 * __cpuidle_register_device - internal register function called before register
442 * and enable routines
Len Brown4f86d3a2007-10-03 18:58:00 -0400443 * @dev: the cpu
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -0400444 *
445 * cpuidle_lock mutex must be held before this is called
Len Brown4f86d3a2007-10-03 18:58:00 -0400446 */
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -0400447static int __cpuidle_register_device(struct cpuidle_device *dev)
Len Brown4f86d3a2007-10-03 18:58:00 -0400448{
449 int ret;
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000450 struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
Len Brown4f86d3a2007-10-03 18:58:00 -0400451
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000452 if (!try_module_get(drv->owner))
Len Brown4f86d3a2007-10-03 18:58:00 -0400453 return -EINVAL;
454
Len Brown4f86d3a2007-10-03 18:58:00 -0400455 per_cpu(cpuidle_devices, dev->cpu) = dev;
456 list_add(&dev->device_list, &cpuidle_detected_devices);
Len Brown4f86d3a2007-10-03 18:58:00 -0400457
Colin Cross4126c012012-05-07 17:57:41 -0700458 ret = cpuidle_coupled_register_device(dev);
Viresh Kumar47182662013-10-03 21:26:46 +0530459 if (ret)
Daniel Lezcanof6bb51a2013-06-12 15:08:53 +0200460 __cpuidle_unregister_device(dev);
Viresh Kumar47182662013-10-03 21:26:46 +0530461 else
462 dev->registered = 1;
Len Brown4f86d3a2007-10-03 18:58:00 -0400463
Viresh Kumar47182662013-10-03 21:26:46 +0530464 return ret;
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -0400465}
466
467/**
468 * cpuidle_register_device - registers a CPU's idle PM feature
469 * @dev: the cpu
470 */
471int cpuidle_register_device(struct cpuidle_device *dev)
472{
Daniel Lezcanoc878a522013-06-12 15:08:55 +0200473 int ret = -EBUSY;
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -0400474
Srivatsa S. Bhat1b0a0e92012-05-04 14:06:02 -0700475 if (!dev)
476 return -EINVAL;
477
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -0400478 mutex_lock(&cpuidle_lock);
479
Daniel Lezcanoc878a522013-06-12 15:08:55 +0200480 if (dev->registered)
481 goto out_unlock;
482
Viresh Kumar267d4bf2013-10-03 21:26:43 +0530483 __cpuidle_device_init(dev);
Daniel Lezcano5df0aa72013-06-12 15:08:54 +0200484
Daniel Lezcanof6bb51a2013-06-12 15:08:53 +0200485 ret = __cpuidle_register_device(dev);
486 if (ret)
487 goto out_unlock;
488
489 ret = cpuidle_add_sysfs(dev);
490 if (ret)
491 goto out_unregister;
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -0400492
Daniel Lezcano10b9d3f2013-06-12 15:08:49 +0200493 ret = cpuidle_enable_device(dev);
Daniel Lezcanof6bb51a2013-06-12 15:08:53 +0200494 if (ret)
495 goto out_sysfs;
Daniel Lezcano10b9d3f2013-06-12 15:08:49 +0200496
Len Brown4f86d3a2007-10-03 18:58:00 -0400497 cpuidle_install_idle_handler();
498
Daniel Lezcanof6bb51a2013-06-12 15:08:53 +0200499out_unlock:
Len Brown4f86d3a2007-10-03 18:58:00 -0400500 mutex_unlock(&cpuidle_lock);
501
Daniel Lezcanof6bb51a2013-06-12 15:08:53 +0200502 return ret;
503
504out_sysfs:
505 cpuidle_remove_sysfs(dev);
506out_unregister:
507 __cpuidle_unregister_device(dev);
508 goto out_unlock;
Len Brown4f86d3a2007-10-03 18:58:00 -0400509}
510
511EXPORT_SYMBOL_GPL(cpuidle_register_device);
512
513/**
514 * cpuidle_unregister_device - unregisters a CPU's idle PM feature
515 * @dev: the cpu
516 */
517void cpuidle_unregister_device(struct cpuidle_device *dev)
518{
Konrad Rzeszutek Wilk813e8e32013-12-03 10:59:58 -0500519 if (!dev || dev->registered == 0)
Venkatesh Pallipadidcb84f32008-05-19 19:09:27 -0400520 return;
521
Len Brown4f86d3a2007-10-03 18:58:00 -0400522 cpuidle_pause_and_lock();
523
524 cpuidle_disable_device(dev);
525
Daniel Lezcano1aef40e2012-10-26 12:26:24 +0200526 cpuidle_remove_sysfs(dev);
Daniel Lezcanof6bb51a2013-06-12 15:08:53 +0200527
528 __cpuidle_unregister_device(dev);
Len Brown4f86d3a2007-10-03 18:58:00 -0400529
Colin Cross4126c012012-05-07 17:57:41 -0700530 cpuidle_coupled_unregister_device(dev);
531
Len Brown4f86d3a2007-10-03 18:58:00 -0400532 cpuidle_resume_and_unlock();
Len Brown4f86d3a2007-10-03 18:58:00 -0400533}
534
535EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
536
Daniel Lezcano1c192d02013-04-23 15:28:44 +0000537/**
Daniel Lezcano4c637b22013-04-23 08:54:33 +0000538 * cpuidle_unregister: unregister a driver and the devices. This function
539 * can be used only if the driver has been previously registered through
540 * the cpuidle_register function.
541 *
542 * @drv: a valid pointer to a struct cpuidle_driver
543 */
544void cpuidle_unregister(struct cpuidle_driver *drv)
545{
546 int cpu;
547 struct cpuidle_device *device;
548
Daniel Lezcano82467a52013-06-07 21:53:09 +0000549 for_each_cpu(cpu, drv->cpumask) {
Daniel Lezcano4c637b22013-04-23 08:54:33 +0000550 device = &per_cpu(cpuidle_dev, cpu);
551 cpuidle_unregister_device(device);
552 }
553
554 cpuidle_unregister_driver(drv);
555}
556EXPORT_SYMBOL_GPL(cpuidle_unregister);
557
558/**
559 * cpuidle_register: registers the driver and the cpu devices with the
560 * coupled_cpus passed as parameter. This function is used for all common
561 * initialization pattern there are in the arch specific drivers. The
562 * devices is globally defined in this file.
563 *
564 * @drv : a valid pointer to a struct cpuidle_driver
565 * @coupled_cpus: a cpumask for the coupled states
566 *
567 * Returns 0 on success, < 0 otherwise
568 */
569int cpuidle_register(struct cpuidle_driver *drv,
570 const struct cpumask *const coupled_cpus)
571{
572 int ret, cpu;
573 struct cpuidle_device *device;
574
575 ret = cpuidle_register_driver(drv);
576 if (ret) {
577 pr_err("failed to register cpuidle driver\n");
578 return ret;
579 }
580
Daniel Lezcano82467a52013-06-07 21:53:09 +0000581 for_each_cpu(cpu, drv->cpumask) {
Daniel Lezcano4c637b22013-04-23 08:54:33 +0000582 device = &per_cpu(cpuidle_dev, cpu);
583 device->cpu = cpu;
584
585#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
586 /*
Viresh Kumarcaf4a362013-10-03 21:26:41 +0530587 * On multiplatform for ARM, the coupled idle states could be
Daniel Lezcano4c637b22013-04-23 08:54:33 +0000588 * enabled in the kernel even if the cpuidle driver does not
589 * use it. Note, coupled_cpus is a struct copy.
590 */
591 if (coupled_cpus)
592 device->coupled_cpus = *coupled_cpus;
593#endif
594 ret = cpuidle_register_device(device);
595 if (!ret)
596 continue;
597
598 pr_err("Failed to register cpuidle device for cpu%d\n", cpu);
599
600 cpuidle_unregister(drv);
601 break;
602 }
603
604 return ret;
605}
606EXPORT_SYMBOL_GPL(cpuidle_register);
607
Len Brown4f86d3a2007-10-03 18:58:00 -0400608#ifdef CONFIG_SMP
609
Len Brown4f86d3a2007-10-03 18:58:00 -0400610/*
611 * This function gets called when a part of the kernel has a new latency
612 * requirement. This means we need to get all processors out of their C-state,
613 * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
614 * wakes them all right up.
615 */
616static int cpuidle_latency_notify(struct notifier_block *b,
617 unsigned long l, void *v)
618{
Chuansheng Liu2ed903c2014-09-04 15:17:55 +0800619 wake_up_all_idle_cpus();
Len Brown4f86d3a2007-10-03 18:58:00 -0400620 return NOTIFY_OK;
621}
622
623static struct notifier_block cpuidle_latency_notifier = {
624 .notifier_call = cpuidle_latency_notify,
625};
626
Mark Grossd82b3512008-02-04 22:30:08 -0800627static inline void latency_notifier_init(struct notifier_block *n)
628{
629 pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
630}
Len Brown4f86d3a2007-10-03 18:58:00 -0400631
632#else /* CONFIG_SMP */
633
634#define latency_notifier_init(x) do { } while (0)
635
636#endif /* CONFIG_SMP */
637
638/**
639 * cpuidle_init - core initializer
640 */
641static int __init cpuidle_init(void)
642{
643 int ret;
644
Len Brown62027ae2011-04-01 18:13:10 -0400645 if (cpuidle_disabled())
646 return -ENODEV;
647
Kay Sievers8a25a2f2011-12-21 14:29:42 -0800648 ret = cpuidle_add_interface(cpu_subsys.dev_root);
Len Brown4f86d3a2007-10-03 18:58:00 -0400649 if (ret)
650 return ret;
651
652 latency_notifier_init(&cpuidle_latency_notifier);
653
654 return 0;
655}
656
Len Brown62027ae2011-04-01 18:13:10 -0400657module_param(off, int, 0444);
Len Brown4f86d3a2007-10-03 18:58:00 -0400658core_initcall(cpuidle_init);