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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 | ||
11 | #include <linux/kernel.h> | |
12 | #include <linux/mutex.h> | |
13 | #include <linux/sched.h> | |
14 | #include <linux/notifier.h> | |
e8db0be1 | 15 | #include <linux/pm_qos.h> |
4f86d3a8 LB |
16 | #include <linux/cpu.h> |
17 | #include <linux/cpuidle.h> | |
9a0b8415 | 18 | #include <linux/ktime.h> |
2e94d1f7 | 19 | #include <linux/hrtimer.h> |
884b17e1 | 20 | #include <linux/module.h> |
288f023e | 21 | #include <trace/events/power.h> |
4f86d3a8 LB |
22 | |
23 | #include "cpuidle.h" | |
24 | ||
25 | DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices); | |
4f86d3a8 LB |
26 | |
27 | DEFINE_MUTEX(cpuidle_lock); | |
28 | LIST_HEAD(cpuidle_detected_devices); | |
4f86d3a8 LB |
29 | |
30 | static int enabled_devices; | |
62027aea | 31 | static int off __read_mostly; |
a0bfa137 | 32 | static int initialized __read_mostly; |
62027aea LB |
33 | |
34 | int cpuidle_disabled(void) | |
35 | { | |
36 | return off; | |
37 | } | |
d91ee586 LB |
38 | void disable_cpuidle(void) |
39 | { | |
40 | off = 1; | |
41 | } | |
4f86d3a8 | 42 | |
dcb84f33 VP |
43 | static int __cpuidle_register_device(struct cpuidle_device *dev); |
44 | ||
e1689795 RL |
45 | static 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 | ||
52 | static 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 | ||
58 | typedef int (*cpuidle_enter_t)(struct cpuidle_device *dev, | |
59 | struct cpuidle_driver *drv, int index); | |
60 | ||
61 | static cpuidle_enter_t cpuidle_enter_ops; | |
62 | ||
1a022e3f BO |
63 | /** |
64 | * cpuidle_play_dead - cpu off-lining | |
65 | * | |
ee01e663 | 66 | * Returns in case of an error or no driver |
1a022e3f BO |
67 | */ |
68 | int 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 | ||
ee01e663 TK |
75 | if (!drv) |
76 | return -ENODEV; | |
77 | ||
1a022e3f BO |
78 | /* 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 | ||
56cfbf74 CC |
94 | /** |
95 | * 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 | */ | |
100 | int 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 | ||
4f86d3a8 LB |
122 | /** |
123 | * cpuidle_idle_call - the main idle loop | |
124 | * | |
125 | * NOTE: no locks or semaphores should be used here | |
a0bfa137 | 126 | * return non-zero on failure |
4f86d3a8 | 127 | */ |
a0bfa137 | 128 | int cpuidle_idle_call(void) |
4f86d3a8 | 129 | { |
4a6f4fe8 | 130 | struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); |
46bcfad7 | 131 | struct cpuidle_driver *drv = cpuidle_get_driver(); |
e978aa7d | 132 | int next_state, entered_state; |
4f86d3a8 | 133 | |
a0bfa137 LB |
134 | if (off) |
135 | return -ENODEV; | |
136 | ||
137 | if (!initialized) | |
138 | return -ENODEV; | |
139 | ||
4f86d3a8 | 140 | /* check if the device is ready */ |
a0bfa137 LB |
141 | if (!dev || !dev->enabled) |
142 | return -EBUSY; | |
4f86d3a8 LB |
143 | |
144 | /* ask the governor for the next state */ | |
46bcfad7 | 145 | next_state = cpuidle_curr_governor->select(drv, dev); |
246eb7f0 KH |
146 | if (need_resched()) { |
147 | local_irq_enable(); | |
a0bfa137 | 148 | return 0; |
246eb7f0 KH |
149 | } |
150 | ||
76027ea8 SR |
151 | trace_power_start_rcuidle(POWER_CSTATE, next_state, dev->cpu); |
152 | trace_cpu_idle_rcuidle(next_state, dev->cpu); | |
f77cfe4e | 153 | |
4126c019 CC |
154 | 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); | |
f77cfe4e | 159 | |
76027ea8 SR |
160 | trace_power_end_rcuidle(dev->cpu); |
161 | trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu); | |
f77cfe4e | 162 | |
4f86d3a8 LB |
163 | /* give the governor an opportunity to reflect on the outcome */ |
164 | if (cpuidle_curr_governor->reflect) | |
e978aa7d | 165 | cpuidle_curr_governor->reflect(dev, entered_state); |
a0bfa137 LB |
166 | |
167 | return 0; | |
4f86d3a8 LB |
168 | } |
169 | ||
170 | /** | |
171 | * cpuidle_install_idle_handler - installs the cpuidle idle loop handler | |
172 | */ | |
173 | void cpuidle_install_idle_handler(void) | |
174 | { | |
a0bfa137 | 175 | if (enabled_devices) { |
4f86d3a8 LB |
176 | /* Make sure all changes finished before we switch to new idle */ |
177 | smp_wmb(); | |
a0bfa137 | 178 | initialized = 1; |
4f86d3a8 LB |
179 | } |
180 | } | |
181 | ||
182 | /** | |
183 | * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler | |
184 | */ | |
185 | void cpuidle_uninstall_idle_handler(void) | |
186 | { | |
a0bfa137 LB |
187 | if (enabled_devices) { |
188 | initialized = 0; | |
4a162513 | 189 | kick_all_cpus_sync(); |
4f86d3a8 LB |
190 | } |
191 | } | |
192 | ||
193 | /** | |
194 | * cpuidle_pause_and_lock - temporarily disables CPUIDLE | |
195 | */ | |
196 | void cpuidle_pause_and_lock(void) | |
197 | { | |
198 | mutex_lock(&cpuidle_lock); | |
199 | cpuidle_uninstall_idle_handler(); | |
200 | } | |
201 | ||
202 | EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock); | |
203 | ||
204 | /** | |
205 | * cpuidle_resume_and_unlock - resumes CPUIDLE operation | |
206 | */ | |
207 | void cpuidle_resume_and_unlock(void) | |
208 | { | |
209 | cpuidle_install_idle_handler(); | |
210 | mutex_unlock(&cpuidle_lock); | |
211 | } | |
212 | ||
213 | EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock); | |
214 | ||
8651f97b PM |
215 | /* Currently used in suspend/resume path to suspend cpuidle */ |
216 | void 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 */ | |
224 | void cpuidle_resume(void) | |
225 | { | |
226 | mutex_lock(&cpuidle_lock); | |
227 | cpuidle_install_idle_handler(); | |
228 | mutex_unlock(&cpuidle_lock); | |
229 | } | |
230 | ||
e1689795 RL |
231 | /** |
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 | */ | |
237 | int 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 | ||
d8c216cf | 262 | #ifdef CONFIG_ARCH_HAS_CPU_RELAX |
46bcfad7 DD |
263 | static int poll_idle(struct cpuidle_device *dev, |
264 | struct cpuidle_driver *drv, int index) | |
d8c216cf RW |
265 | { |
266 | ktime_t t1, t2; | |
267 | s64 diff; | |
d8c216cf RW |
268 | |
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 | ||
e978aa7d DD |
279 | dev->last_residency = (int) diff; |
280 | ||
281 | return index; | |
d8c216cf RW |
282 | } |
283 | ||
46bcfad7 | 284 | static void poll_idle_init(struct cpuidle_driver *drv) |
d8c216cf | 285 | { |
46bcfad7 | 286 | struct cpuidle_state *state = &drv->states[0]; |
d8c216cf | 287 | |
720f1c30 | 288 | snprintf(state->name, CPUIDLE_NAME_LEN, "POLL"); |
d8c216cf RW |
289 | 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; | |
d247632c | 293 | state->flags = 0; |
d8c216cf | 294 | state->enter = poll_idle; |
cbc9ef02 | 295 | state->disabled = false; |
d8c216cf RW |
296 | } |
297 | #else | |
46bcfad7 | 298 | static void poll_idle_init(struct cpuidle_driver *drv) {} |
d8c216cf RW |
299 | #endif /* CONFIG_ARCH_HAS_CPU_RELAX */ |
300 | ||
4f86d3a8 LB |
301 | /** |
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 | */ | |
308 | int cpuidle_enable_device(struct cpuidle_device *dev) | |
309 | { | |
310 | int ret, i; | |
e1689795 | 311 | struct cpuidle_driver *drv = cpuidle_get_driver(); |
4f86d3a8 | 312 | |
1b0a0e9a SB |
313 | if (!dev) |
314 | return -EINVAL; | |
315 | ||
4f86d3a8 LB |
316 | if (dev->enabled) |
317 | return 0; | |
e1689795 | 318 | if (!drv || !cpuidle_curr_governor) |
4f86d3a8 LB |
319 | return -EIO; |
320 | if (!dev->state_count) | |
fc850f39 | 321 | dev->state_count = drv->state_count; |
4f86d3a8 | 322 | |
dcb84f33 VP |
323 | if (dev->registered == 0) { |
324 | ret = __cpuidle_register_device(dev); | |
325 | if (ret) | |
326 | return ret; | |
327 | } | |
328 | ||
e1689795 RL |
329 | cpuidle_enter_ops = drv->en_core_tk_irqen ? |
330 | cpuidle_enter_tk : cpuidle_enter; | |
331 | ||
332 | poll_idle_init(drv); | |
d8c216cf | 333 | |
4f86d3a8 LB |
334 | if ((ret = cpuidle_add_state_sysfs(dev))) |
335 | return ret; | |
336 | ||
337 | if (cpuidle_curr_governor->enable && | |
e1689795 | 338 | (ret = cpuidle_curr_governor->enable(drv, dev))) |
4f86d3a8 LB |
339 | goto fail_sysfs; |
340 | ||
341 | for (i = 0; i < dev->state_count; i++) { | |
4202735e DD |
342 | dev->states_usage[i].usage = 0; |
343 | dev->states_usage[i].time = 0; | |
4f86d3a8 LB |
344 | } |
345 | dev->last_residency = 0; | |
4f86d3a8 LB |
346 | |
347 | smp_wmb(); | |
348 | ||
349 | dev->enabled = 1; | |
350 | ||
351 | enabled_devices++; | |
352 | return 0; | |
353 | ||
354 | fail_sysfs: | |
355 | cpuidle_remove_state_sysfs(dev); | |
356 | ||
357 | return ret; | |
358 | } | |
359 | ||
360 | EXPORT_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 | */ | |
369 | void cpuidle_disable_device(struct cpuidle_device *dev) | |
370 | { | |
371 | if (!dev->enabled) | |
372 | return; | |
752138df | 373 | if (!cpuidle_get_driver() || !cpuidle_curr_governor) |
4f86d3a8 LB |
374 | return; |
375 | ||
376 | dev->enabled = 0; | |
377 | ||
378 | if (cpuidle_curr_governor->disable) | |
46bcfad7 | 379 | cpuidle_curr_governor->disable(cpuidle_get_driver(), dev); |
4f86d3a8 LB |
380 | |
381 | cpuidle_remove_state_sysfs(dev); | |
382 | enabled_devices--; | |
383 | } | |
384 | ||
385 | EXPORT_SYMBOL_GPL(cpuidle_disable_device); | |
386 | ||
387 | /** | |
dcb84f33 VP |
388 | * __cpuidle_register_device - internal register function called before register |
389 | * and enable routines | |
4f86d3a8 | 390 | * @dev: the cpu |
dcb84f33 VP |
391 | * |
392 | * cpuidle_lock mutex must be held before this is called | |
4f86d3a8 | 393 | */ |
dcb84f33 | 394 | static int __cpuidle_register_device(struct cpuidle_device *dev) |
4f86d3a8 LB |
395 | { |
396 | int ret; | |
8a25a2fd | 397 | struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu); |
752138df | 398 | struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver(); |
4f86d3a8 | 399 | |
752138df | 400 | if (!try_module_get(cpuidle_driver->owner)) |
4f86d3a8 LB |
401 | return -EINVAL; |
402 | ||
403 | init_completion(&dev->kobj_unregister); | |
404 | ||
4f86d3a8 LB |
405 | per_cpu(cpuidle_devices, dev->cpu) = dev; |
406 | list_add(&dev->device_list, &cpuidle_detected_devices); | |
3af272ab CC |
407 | ret = cpuidle_add_sysfs(cpu_dev); |
408 | if (ret) | |
409 | goto err_sysfs; | |
4f86d3a8 | 410 | |
4126c019 CC |
411 | ret = cpuidle_coupled_register_device(dev); |
412 | if (ret) | |
413 | goto err_coupled; | |
4f86d3a8 | 414 | |
dcb84f33 VP |
415 | dev->registered = 1; |
416 | return 0; | |
3af272ab | 417 | |
4126c019 CC |
418 | err_coupled: |
419 | cpuidle_remove_sysfs(cpu_dev); | |
420 | wait_for_completion(&dev->kobj_unregister); | |
3af272ab CC |
421 | err_sysfs: |
422 | list_del(&dev->device_list); | |
423 | per_cpu(cpuidle_devices, dev->cpu) = NULL; | |
424 | module_put(cpuidle_driver->owner); | |
425 | return ret; | |
dcb84f33 VP |
426 | } |
427 | ||
428 | /** | |
429 | * cpuidle_register_device - registers a CPU's idle PM feature | |
430 | * @dev: the cpu | |
431 | */ | |
432 | int cpuidle_register_device(struct cpuidle_device *dev) | |
433 | { | |
434 | int ret; | |
435 | ||
1b0a0e9a SB |
436 | if (!dev) |
437 | return -EINVAL; | |
438 | ||
dcb84f33 VP |
439 | mutex_lock(&cpuidle_lock); |
440 | ||
441 | if ((ret = __cpuidle_register_device(dev))) { | |
442 | mutex_unlock(&cpuidle_lock); | |
443 | return ret; | |
444 | } | |
445 | ||
4f86d3a8 LB |
446 | cpuidle_enable_device(dev); |
447 | cpuidle_install_idle_handler(); | |
448 | ||
449 | mutex_unlock(&cpuidle_lock); | |
450 | ||
451 | return 0; | |
452 | ||
453 | } | |
454 | ||
455 | EXPORT_SYMBOL_GPL(cpuidle_register_device); | |
456 | ||
457 | /** | |
458 | * cpuidle_unregister_device - unregisters a CPU's idle PM feature | |
459 | * @dev: the cpu | |
460 | */ | |
461 | void cpuidle_unregister_device(struct cpuidle_device *dev) | |
462 | { | |
8a25a2fd | 463 | struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu); |
752138df | 464 | struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver(); |
4f86d3a8 | 465 | |
dcb84f33 VP |
466 | if (dev->registered == 0) |
467 | return; | |
468 | ||
4f86d3a8 LB |
469 | cpuidle_pause_and_lock(); |
470 | ||
471 | cpuidle_disable_device(dev); | |
472 | ||
8a25a2fd | 473 | cpuidle_remove_sysfs(cpu_dev); |
4f86d3a8 LB |
474 | list_del(&dev->device_list); |
475 | wait_for_completion(&dev->kobj_unregister); | |
476 | per_cpu(cpuidle_devices, dev->cpu) = NULL; | |
477 | ||
4126c019 CC |
478 | cpuidle_coupled_unregister_device(dev); |
479 | ||
4f86d3a8 LB |
480 | cpuidle_resume_and_unlock(); |
481 | ||
752138df | 482 | module_put(cpuidle_driver->owner); |
4f86d3a8 LB |
483 | } |
484 | ||
485 | EXPORT_SYMBOL_GPL(cpuidle_unregister_device); | |
486 | ||
487 | #ifdef CONFIG_SMP | |
488 | ||
489 | static 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 | */ | |
500 | static int cpuidle_latency_notify(struct notifier_block *b, | |
501 | unsigned long l, void *v) | |
502 | { | |
8691e5a8 | 503 | smp_call_function(smp_callback, NULL, 1); |
4f86d3a8 LB |
504 | return NOTIFY_OK; |
505 | } | |
506 | ||
507 | static struct notifier_block cpuidle_latency_notifier = { | |
508 | .notifier_call = cpuidle_latency_notify, | |
509 | }; | |
510 | ||
d82b3518 MG |
511 | static inline void latency_notifier_init(struct notifier_block *n) |
512 | { | |
513 | pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n); | |
514 | } | |
4f86d3a8 LB |
515 | |
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 | */ | |
525 | static int __init cpuidle_init(void) | |
526 | { | |
527 | int ret; | |
528 | ||
62027aea LB |
529 | if (cpuidle_disabled()) |
530 | return -ENODEV; | |
531 | ||
8a25a2fd | 532 | ret = cpuidle_add_interface(cpu_subsys.dev_root); |
4f86d3a8 LB |
533 | if (ret) |
534 | return ret; | |
535 | ||
536 | latency_notifier_init(&cpuidle_latency_notifier); | |
537 | ||
538 | return 0; | |
539 | } | |
540 | ||
62027aea | 541 | module_param(off, int, 0444); |
4f86d3a8 | 542 | core_initcall(cpuidle_init); |