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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, | |
28ba086e | 80 | bool s2idle) |
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) | |
28ba086e | 92 | || (s2idle && !s->enter_s2idle)) |
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(); | |
41dc750e LF |
114 | if (dev) |
115 | dev->use_deepest_state = enable; | |
bb8313b6 JP |
116 | preempt_enable(); |
117 | } | |
118 | ||
ef2b22ac RW |
119 | /** |
120 | * cpuidle_find_deepest_state - Find the deepest available idle state. | |
121 | * @drv: cpuidle driver for the given CPU. | |
122 | * @dev: cpuidle device for the given CPU. | |
123 | */ | |
124 | int cpuidle_find_deepest_state(struct cpuidle_driver *drv, | |
125 | struct cpuidle_device *dev) | |
126 | { | |
0d94039f | 127 | return find_deepest_state(drv, dev, UINT_MAX, 0, false); |
ef2b22ac RW |
128 | } |
129 | ||
bb8313b6 | 130 | #ifdef CONFIG_SUSPEND |
28ba086e | 131 | static void enter_s2idle_proper(struct cpuidle_driver *drv, |
124cf911 RW |
132 | struct cpuidle_device *dev, int index) |
133 | { | |
64bdff69 RW |
134 | ktime_t time_start, time_end; |
135 | ||
136 | time_start = ns_to_ktime(local_clock()); | |
137 | ||
ae0afb4f RW |
138 | /* |
139 | * trace_suspend_resume() called by tick_freeze() for the last CPU | |
140 | * executing it contains RCU usage regarded as invalid in the idle | |
141 | * context, so tell RCU about that. | |
142 | */ | |
143 | RCU_NONIDLE(tick_freeze()); | |
124cf911 RW |
144 | /* |
145 | * The state used here cannot be a "coupled" one, because the "coupled" | |
146 | * cpuidle mechanism enables interrupts and doing that with timekeeping | |
147 | * suspended is generally unsafe. | |
148 | */ | |
63caae84 | 149 | stop_critical_timings(); |
28ba086e | 150 | drv->states[index].enter_s2idle(dev, drv, index); |
124cf911 RW |
151 | WARN_ON(!irqs_disabled()); |
152 | /* | |
153 | * timekeeping_resume() that will be called by tick_unfreeze() for the | |
ae0afb4f | 154 | * first CPU executing it calls functions containing RCU read-side |
124cf911 RW |
155 | * critical sections, so tell RCU about that. |
156 | */ | |
157 | RCU_NONIDLE(tick_unfreeze()); | |
63caae84 | 158 | start_critical_timings(); |
64bdff69 RW |
159 | |
160 | time_end = ns_to_ktime(local_clock()); | |
161 | ||
162 | dev->states_usage[index].s2idle_time += ktime_us_delta(time_end, time_start); | |
163 | dev->states_usage[index].s2idle_usage++; | |
124cf911 RW |
164 | } |
165 | ||
38106313 | 166 | /** |
28ba086e | 167 | * cpuidle_enter_s2idle - Enter an idle state suitable for suspend-to-idle. |
ef2b22ac RW |
168 | * @drv: cpuidle driver for the given CPU. |
169 | * @dev: cpuidle device for the given CPU. | |
38106313 | 170 | * |
28ba086e | 171 | * If there are states with the ->enter_s2idle callback, find the deepest of |
ef2b22ac | 172 | * them and enter it with frozen tick. |
38106313 | 173 | */ |
28ba086e | 174 | int cpuidle_enter_s2idle(struct cpuidle_driver *drv, struct cpuidle_device *dev) |
38106313 | 175 | { |
38106313 RW |
176 | int index; |
177 | ||
124cf911 | 178 | /* |
28ba086e | 179 | * Find the deepest state with ->enter_s2idle present, which guarantees |
124cf911 RW |
180 | * that interrupts won't be enabled when it exits and allows the tick to |
181 | * be frozen safely. | |
182 | */ | |
0d94039f | 183 | index = find_deepest_state(drv, dev, UINT_MAX, 0, true); |
6f16886b | 184 | if (index > 0) |
28ba086e | 185 | enter_s2idle_proper(drv, dev, index); |
124cf911 | 186 | |
ef2b22ac | 187 | return index; |
38106313 | 188 | } |
87e9b9f1 | 189 | #endif /* CONFIG_SUSPEND */ |
38106313 | 190 | |
56cfbf74 CC |
191 | /** |
192 | * cpuidle_enter_state - enter the state and update stats | |
193 | * @dev: cpuidle device for this cpu | |
194 | * @drv: cpuidle driver for this cpu | |
7312280b | 195 | * @index: index into the states table in @drv of the state to enter |
56cfbf74 CC |
196 | */ |
197 | int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, | |
554c06ba | 198 | int index) |
56cfbf74 CC |
199 | { |
200 | int entered_state; | |
201 | ||
554c06ba | 202 | struct cpuidle_state *target_state = &drv->states[index]; |
df8d9eea | 203 | bool broadcast = !!(target_state->flags & CPUIDLE_FLAG_TIMER_STOP); |
dbd1b8ea | 204 | ktime_t time_start, time_end; |
554c06ba DL |
205 | s64 diff; |
206 | ||
df8d9eea RW |
207 | /* |
208 | * Tell the time framework to switch to a broadcast timer because our | |
209 | * local timer will be shut down. If a local timer is used from another | |
210 | * CPU as a broadcast timer, this call may fail if it is not available. | |
211 | */ | |
827a5aef | 212 | if (broadcast && tick_broadcast_enter()) { |
0d94039f RW |
213 | index = find_deepest_state(drv, dev, target_state->exit_latency, |
214 | CPUIDLE_FLAG_TIMER_STOP, false); | |
215 | if (index < 0) { | |
216 | default_idle_call(); | |
217 | return -EBUSY; | |
218 | } | |
219 | target_state = &drv->states[index]; | |
f187851b | 220 | broadcast = false; |
827a5aef | 221 | } |
df8d9eea | 222 | |
faad3849 RW |
223 | /* Take note of the planned idle state. */ |
224 | sched_idle_set_state(target_state); | |
225 | ||
30fe6884 | 226 | trace_cpu_idle_rcuidle(index, dev->cpu); |
dbd1b8ea | 227 | time_start = ns_to_ktime(local_clock()); |
554c06ba | 228 | |
63caae84 | 229 | stop_critical_timings(); |
554c06ba | 230 | entered_state = target_state->enter(dev, drv, index); |
63caae84 | 231 | start_critical_timings(); |
554c06ba | 232 | |
f9fccdb9 | 233 | sched_clock_idle_wakeup_event(); |
dbd1b8ea | 234 | time_end = ns_to_ktime(local_clock()); |
30fe6884 | 235 | trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu); |
554c06ba | 236 | |
faad3849 RW |
237 | /* The cpu is no longer idle or about to enter idle. */ |
238 | sched_idle_set_state(NULL); | |
239 | ||
df8d9eea RW |
240 | if (broadcast) { |
241 | if (WARN_ON_ONCE(!irqs_disabled())) | |
242 | local_irq_disable(); | |
243 | ||
244 | tick_broadcast_exit(); | |
245 | } | |
246 | ||
e7387da5 | 247 | if (!cpuidle_state_is_coupled(drv, index)) |
0b89e9aa | 248 | local_irq_enable(); |
554c06ba | 249 | |
dbd1b8ea | 250 | diff = ktime_us_delta(time_end, time_start); |
554c06ba DL |
251 | if (diff > INT_MAX) |
252 | diff = INT_MAX; | |
253 | ||
254 | dev->last_residency = (int) diff; | |
56cfbf74 CC |
255 | |
256 | if (entered_state >= 0) { | |
257 | /* Update cpuidle counters */ | |
258 | /* This can be moved to within driver enter routine | |
259 | * but that results in multiple copies of same code. | |
260 | */ | |
a474a515 | 261 | dev->states_usage[entered_state].time += dev->last_residency; |
56cfbf74 CC |
262 | dev->states_usage[entered_state].usage++; |
263 | } else { | |
264 | dev->last_residency = 0; | |
265 | } | |
266 | ||
267 | return entered_state; | |
268 | } | |
269 | ||
4f86d3a8 | 270 | /** |
907e30f1 DL |
271 | * cpuidle_select - ask the cpuidle framework to choose an idle state |
272 | * | |
273 | * @drv: the cpuidle driver | |
274 | * @dev: the cpuidle device | |
45f1ff59 | 275 | * @stop_tick: indication on whether or not to stop the tick |
4f86d3a8 | 276 | * |
51164251 | 277 | * Returns the index of the idle state. The return value must not be negative. |
45f1ff59 RW |
278 | * |
279 | * The memory location pointed to by @stop_tick is expected to be written the | |
280 | * 'false' boolean value if the scheduler tick should not be stopped before | |
281 | * entering the returned state. | |
4f86d3a8 | 282 | */ |
45f1ff59 RW |
283 | int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev, |
284 | bool *stop_tick) | |
4f86d3a8 | 285 | { |
45f1ff59 | 286 | return cpuidle_curr_governor->select(drv, dev, stop_tick); |
907e30f1 | 287 | } |
ba8f20c2 | 288 | |
907e30f1 DL |
289 | /** |
290 | * cpuidle_enter - enter into the specified idle state | |
291 | * | |
292 | * @drv: the cpuidle driver tied with the cpu | |
293 | * @dev: the cpuidle device | |
294 | * @index: the index in the idle state table | |
295 | * | |
296 | * Returns the index in the idle state, < 0 in case of error. | |
297 | * The error code depends on the backend driver | |
298 | */ | |
299 | int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev, | |
300 | int index) | |
301 | { | |
4c1ed5a6 | 302 | if (cpuidle_state_is_coupled(drv, index)) |
907e30f1 DL |
303 | return cpuidle_enter_state_coupled(dev, drv, index); |
304 | return cpuidle_enter_state(dev, drv, index); | |
305 | } | |
b60e6a0e | 306 | |
907e30f1 DL |
307 | /** |
308 | * cpuidle_reflect - tell the underlying governor what was the state | |
309 | * we were in | |
310 | * | |
311 | * @dev : the cpuidle device | |
312 | * @index: the index in the idle state table | |
313 | * | |
314 | */ | |
315 | void cpuidle_reflect(struct cpuidle_device *dev, int index) | |
316 | { | |
a802ea96 | 317 | if (cpuidle_curr_governor->reflect && index >= 0) |
907e30f1 | 318 | cpuidle_curr_governor->reflect(dev, index); |
4f86d3a8 LB |
319 | } |
320 | ||
321 | /** | |
322 | * cpuidle_install_idle_handler - installs the cpuidle idle loop handler | |
323 | */ | |
324 | void cpuidle_install_idle_handler(void) | |
325 | { | |
a0bfa137 | 326 | if (enabled_devices) { |
4f86d3a8 LB |
327 | /* Make sure all changes finished before we switch to new idle */ |
328 | smp_wmb(); | |
a0bfa137 | 329 | initialized = 1; |
4f86d3a8 LB |
330 | } |
331 | } | |
332 | ||
333 | /** | |
334 | * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler | |
335 | */ | |
336 | void cpuidle_uninstall_idle_handler(void) | |
337 | { | |
a0bfa137 LB |
338 | if (enabled_devices) { |
339 | initialized = 0; | |
2ed903c5 | 340 | wake_up_all_idle_cpus(); |
4f86d3a8 | 341 | } |
442bf3aa DL |
342 | |
343 | /* | |
344 | * Make sure external observers (such as the scheduler) | |
345 | * are done looking at pointed idle states. | |
346 | */ | |
347 | synchronize_rcu(); | |
4f86d3a8 LB |
348 | } |
349 | ||
350 | /** | |
351 | * cpuidle_pause_and_lock - temporarily disables CPUIDLE | |
352 | */ | |
353 | void cpuidle_pause_and_lock(void) | |
354 | { | |
355 | mutex_lock(&cpuidle_lock); | |
356 | cpuidle_uninstall_idle_handler(); | |
357 | } | |
358 | ||
359 | EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock); | |
360 | ||
361 | /** | |
362 | * cpuidle_resume_and_unlock - resumes CPUIDLE operation | |
363 | */ | |
364 | void cpuidle_resume_and_unlock(void) | |
365 | { | |
366 | cpuidle_install_idle_handler(); | |
367 | mutex_unlock(&cpuidle_lock); | |
368 | } | |
369 | ||
370 | EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock); | |
371 | ||
8651f97b PM |
372 | /* Currently used in suspend/resume path to suspend cpuidle */ |
373 | void cpuidle_pause(void) | |
374 | { | |
375 | mutex_lock(&cpuidle_lock); | |
376 | cpuidle_uninstall_idle_handler(); | |
377 | mutex_unlock(&cpuidle_lock); | |
378 | } | |
379 | ||
380 | /* Currently used in suspend/resume path to resume cpuidle */ | |
381 | void cpuidle_resume(void) | |
382 | { | |
383 | mutex_lock(&cpuidle_lock); | |
384 | cpuidle_install_idle_handler(); | |
385 | mutex_unlock(&cpuidle_lock); | |
386 | } | |
387 | ||
4f86d3a8 LB |
388 | /** |
389 | * cpuidle_enable_device - enables idle PM for a CPU | |
390 | * @dev: the CPU | |
391 | * | |
392 | * This function must be called between cpuidle_pause_and_lock and | |
393 | * cpuidle_resume_and_unlock when used externally. | |
394 | */ | |
395 | int cpuidle_enable_device(struct cpuidle_device *dev) | |
396 | { | |
5df0aa73 | 397 | int ret; |
bf4d1b5d | 398 | struct cpuidle_driver *drv; |
4f86d3a8 | 399 | |
1b0a0e9a SB |
400 | if (!dev) |
401 | return -EINVAL; | |
402 | ||
4f86d3a8 LB |
403 | if (dev->enabled) |
404 | return 0; | |
bf4d1b5d | 405 | |
e7b06a09 GJ |
406 | if (!cpuidle_curr_governor) |
407 | return -EIO; | |
408 | ||
bf4d1b5d DL |
409 | drv = cpuidle_get_cpu_driver(dev); |
410 | ||
e7b06a09 | 411 | if (!drv) |
4f86d3a8 | 412 | return -EIO; |
bf4d1b5d | 413 | |
10b9d3f8 DL |
414 | if (!dev->registered) |
415 | return -EINVAL; | |
416 | ||
bf4d1b5d DL |
417 | ret = cpuidle_add_device_sysfs(dev); |
418 | if (ret) | |
4f86d3a8 LB |
419 | return ret; |
420 | ||
3fc74bd8 GJ |
421 | if (cpuidle_curr_governor->enable) { |
422 | ret = cpuidle_curr_governor->enable(drv, dev); | |
423 | if (ret) | |
424 | goto fail_sysfs; | |
425 | } | |
4f86d3a8 | 426 | |
4f86d3a8 LB |
427 | smp_wmb(); |
428 | ||
429 | dev->enabled = 1; | |
430 | ||
431 | enabled_devices++; | |
432 | return 0; | |
433 | ||
434 | fail_sysfs: | |
bf4d1b5d | 435 | cpuidle_remove_device_sysfs(dev); |
4f86d3a8 LB |
436 | |
437 | return ret; | |
438 | } | |
439 | ||
440 | EXPORT_SYMBOL_GPL(cpuidle_enable_device); | |
441 | ||
442 | /** | |
443 | * cpuidle_disable_device - disables idle PM for a CPU | |
444 | * @dev: the CPU | |
445 | * | |
446 | * This function must be called between cpuidle_pause_and_lock and | |
447 | * cpuidle_resume_and_unlock when used externally. | |
448 | */ | |
449 | void cpuidle_disable_device(struct cpuidle_device *dev) | |
450 | { | |
bf4d1b5d DL |
451 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
452 | ||
cf31cd1a | 453 | if (!dev || !dev->enabled) |
4f86d3a8 | 454 | return; |
bf4d1b5d DL |
455 | |
456 | if (!drv || !cpuidle_curr_governor) | |
4f86d3a8 LB |
457 | return; |
458 | ||
459 | dev->enabled = 0; | |
460 | ||
461 | if (cpuidle_curr_governor->disable) | |
bf4d1b5d | 462 | cpuidle_curr_governor->disable(drv, dev); |
4f86d3a8 | 463 | |
bf4d1b5d | 464 | cpuidle_remove_device_sysfs(dev); |
4f86d3a8 LB |
465 | enabled_devices--; |
466 | } | |
467 | ||
468 | EXPORT_SYMBOL_GPL(cpuidle_disable_device); | |
469 | ||
f6bb51a5 DL |
470 | static void __cpuidle_unregister_device(struct cpuidle_device *dev) |
471 | { | |
472 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); | |
473 | ||
474 | list_del(&dev->device_list); | |
475 | per_cpu(cpuidle_devices, dev->cpu) = NULL; | |
476 | module_put(drv->owner); | |
c998c078 DG |
477 | |
478 | dev->registered = 0; | |
f6bb51a5 DL |
479 | } |
480 | ||
267d4bf8 | 481 | static void __cpuidle_device_init(struct cpuidle_device *dev) |
5df0aa73 DL |
482 | { |
483 | memset(dev->states_usage, 0, sizeof(dev->states_usage)); | |
484 | dev->last_residency = 0; | |
5df0aa73 DL |
485 | } |
486 | ||
4f86d3a8 | 487 | /** |
dcb84f33 VP |
488 | * __cpuidle_register_device - internal register function called before register |
489 | * and enable routines | |
4f86d3a8 | 490 | * @dev: the cpu |
dcb84f33 VP |
491 | * |
492 | * cpuidle_lock mutex must be held before this is called | |
4f86d3a8 | 493 | */ |
dcb84f33 | 494 | static int __cpuidle_register_device(struct cpuidle_device *dev) |
4f86d3a8 LB |
495 | { |
496 | int ret; | |
bf4d1b5d | 497 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
4f86d3a8 | 498 | |
bf4d1b5d | 499 | if (!try_module_get(drv->owner)) |
4f86d3a8 LB |
500 | return -EINVAL; |
501 | ||
4f86d3a8 LB |
502 | per_cpu(cpuidle_devices, dev->cpu) = dev; |
503 | list_add(&dev->device_list, &cpuidle_detected_devices); | |
4f86d3a8 | 504 | |
4126c019 | 505 | ret = cpuidle_coupled_register_device(dev); |
47182668 | 506 | if (ret) |
f6bb51a5 | 507 | __cpuidle_unregister_device(dev); |
47182668 VK |
508 | else |
509 | dev->registered = 1; | |
4f86d3a8 | 510 | |
47182668 | 511 | return ret; |
dcb84f33 VP |
512 | } |
513 | ||
514 | /** | |
515 | * cpuidle_register_device - registers a CPU's idle PM feature | |
516 | * @dev: the cpu | |
517 | */ | |
518 | int cpuidle_register_device(struct cpuidle_device *dev) | |
519 | { | |
c878a52d | 520 | int ret = -EBUSY; |
dcb84f33 | 521 | |
1b0a0e9a SB |
522 | if (!dev) |
523 | return -EINVAL; | |
524 | ||
dcb84f33 VP |
525 | mutex_lock(&cpuidle_lock); |
526 | ||
c878a52d DL |
527 | if (dev->registered) |
528 | goto out_unlock; | |
529 | ||
267d4bf8 | 530 | __cpuidle_device_init(dev); |
5df0aa73 | 531 | |
f6bb51a5 DL |
532 | ret = __cpuidle_register_device(dev); |
533 | if (ret) | |
534 | goto out_unlock; | |
535 | ||
536 | ret = cpuidle_add_sysfs(dev); | |
537 | if (ret) | |
538 | goto out_unregister; | |
dcb84f33 | 539 | |
10b9d3f8 | 540 | ret = cpuidle_enable_device(dev); |
f6bb51a5 DL |
541 | if (ret) |
542 | goto out_sysfs; | |
10b9d3f8 | 543 | |
4f86d3a8 LB |
544 | cpuidle_install_idle_handler(); |
545 | ||
f6bb51a5 | 546 | out_unlock: |
4f86d3a8 LB |
547 | mutex_unlock(&cpuidle_lock); |
548 | ||
f6bb51a5 DL |
549 | return ret; |
550 | ||
551 | out_sysfs: | |
552 | cpuidle_remove_sysfs(dev); | |
553 | out_unregister: | |
554 | __cpuidle_unregister_device(dev); | |
555 | goto out_unlock; | |
4f86d3a8 LB |
556 | } |
557 | ||
558 | EXPORT_SYMBOL_GPL(cpuidle_register_device); | |
559 | ||
560 | /** | |
561 | * cpuidle_unregister_device - unregisters a CPU's idle PM feature | |
562 | * @dev: the cpu | |
563 | */ | |
564 | void cpuidle_unregister_device(struct cpuidle_device *dev) | |
565 | { | |
813e8e3d | 566 | if (!dev || dev->registered == 0) |
dcb84f33 VP |
567 | return; |
568 | ||
4f86d3a8 LB |
569 | cpuidle_pause_and_lock(); |
570 | ||
571 | cpuidle_disable_device(dev); | |
572 | ||
1aef40e2 | 573 | cpuidle_remove_sysfs(dev); |
f6bb51a5 DL |
574 | |
575 | __cpuidle_unregister_device(dev); | |
4f86d3a8 | 576 | |
4126c019 CC |
577 | cpuidle_coupled_unregister_device(dev); |
578 | ||
4f86d3a8 | 579 | cpuidle_resume_and_unlock(); |
4f86d3a8 LB |
580 | } |
581 | ||
582 | EXPORT_SYMBOL_GPL(cpuidle_unregister_device); | |
583 | ||
1c192d04 | 584 | /** |
4c637b21 DL |
585 | * cpuidle_unregister: unregister a driver and the devices. This function |
586 | * can be used only if the driver has been previously registered through | |
587 | * the cpuidle_register function. | |
588 | * | |
589 | * @drv: a valid pointer to a struct cpuidle_driver | |
590 | */ | |
591 | void cpuidle_unregister(struct cpuidle_driver *drv) | |
592 | { | |
593 | int cpu; | |
594 | struct cpuidle_device *device; | |
595 | ||
82467a5a | 596 | for_each_cpu(cpu, drv->cpumask) { |
4c637b21 DL |
597 | device = &per_cpu(cpuidle_dev, cpu); |
598 | cpuidle_unregister_device(device); | |
599 | } | |
600 | ||
601 | cpuidle_unregister_driver(drv); | |
602 | } | |
603 | EXPORT_SYMBOL_GPL(cpuidle_unregister); | |
604 | ||
605 | /** | |
606 | * cpuidle_register: registers the driver and the cpu devices with the | |
607 | * coupled_cpus passed as parameter. This function is used for all common | |
608 | * initialization pattern there are in the arch specific drivers. The | |
609 | * devices is globally defined in this file. | |
610 | * | |
611 | * @drv : a valid pointer to a struct cpuidle_driver | |
612 | * @coupled_cpus: a cpumask for the coupled states | |
613 | * | |
614 | * Returns 0 on success, < 0 otherwise | |
615 | */ | |
616 | int cpuidle_register(struct cpuidle_driver *drv, | |
617 | const struct cpumask *const coupled_cpus) | |
618 | { | |
619 | int ret, cpu; | |
620 | struct cpuidle_device *device; | |
621 | ||
622 | ret = cpuidle_register_driver(drv); | |
623 | if (ret) { | |
624 | pr_err("failed to register cpuidle driver\n"); | |
625 | return ret; | |
626 | } | |
627 | ||
82467a5a | 628 | for_each_cpu(cpu, drv->cpumask) { |
4c637b21 DL |
629 | device = &per_cpu(cpuidle_dev, cpu); |
630 | device->cpu = cpu; | |
631 | ||
632 | #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED | |
633 | /* | |
caf4a36e | 634 | * On multiplatform for ARM, the coupled idle states could be |
4c637b21 DL |
635 | * enabled in the kernel even if the cpuidle driver does not |
636 | * use it. Note, coupled_cpus is a struct copy. | |
637 | */ | |
638 | if (coupled_cpus) | |
639 | device->coupled_cpus = *coupled_cpus; | |
640 | #endif | |
641 | ret = cpuidle_register_device(device); | |
642 | if (!ret) | |
643 | continue; | |
644 | ||
645 | pr_err("Failed to register cpuidle device for cpu%d\n", cpu); | |
646 | ||
647 | cpuidle_unregister(drv); | |
648 | break; | |
649 | } | |
650 | ||
651 | return ret; | |
652 | } | |
653 | EXPORT_SYMBOL_GPL(cpuidle_register); | |
654 | ||
4f86d3a8 LB |
655 | #ifdef CONFIG_SMP |
656 | ||
4f86d3a8 LB |
657 | /* |
658 | * This function gets called when a part of the kernel has a new latency | |
659 | * requirement. This means we need to get all processors out of their C-state, | |
660 | * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that | |
661 | * wakes them all right up. | |
662 | */ | |
663 | static int cpuidle_latency_notify(struct notifier_block *b, | |
664 | unsigned long l, void *v) | |
665 | { | |
2ed903c5 | 666 | wake_up_all_idle_cpus(); |
4f86d3a8 LB |
667 | return NOTIFY_OK; |
668 | } | |
669 | ||
670 | static struct notifier_block cpuidle_latency_notifier = { | |
671 | .notifier_call = cpuidle_latency_notify, | |
672 | }; | |
673 | ||
d82b3518 MG |
674 | static inline void latency_notifier_init(struct notifier_block *n) |
675 | { | |
676 | pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n); | |
677 | } | |
4f86d3a8 LB |
678 | |
679 | #else /* CONFIG_SMP */ | |
680 | ||
681 | #define latency_notifier_init(x) do { } while (0) | |
682 | ||
683 | #endif /* CONFIG_SMP */ | |
684 | ||
685 | /** | |
686 | * cpuidle_init - core initializer | |
687 | */ | |
688 | static int __init cpuidle_init(void) | |
689 | { | |
690 | int ret; | |
691 | ||
62027aea LB |
692 | if (cpuidle_disabled()) |
693 | return -ENODEV; | |
694 | ||
8a25a2fd | 695 | ret = cpuidle_add_interface(cpu_subsys.dev_root); |
4f86d3a8 LB |
696 | if (ret) |
697 | return ret; | |
698 | ||
699 | latency_notifier_init(&cpuidle_latency_notifier); | |
700 | ||
701 | return 0; | |
702 | } | |
703 | ||
62027aea | 704 | module_param(off, int, 0444); |
4f86d3a8 | 705 | core_initcall(cpuidle_init); |