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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 | |
a6869cc4 VP |
43 | #if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT) |
44 | static void cpuidle_kick_cpus(void) | |
45 | { | |
46 | cpu_idle_wait(); | |
47 | } | |
48 | #elif defined(CONFIG_SMP) | |
49 | # error "Arch needs cpu_idle_wait() equivalent here" | |
50 | #else /* !CONFIG_ARCH_HAS_CPU_IDLE_WAIT && !CONFIG_SMP */ | |
51 | static void cpuidle_kick_cpus(void) {} | |
52 | #endif | |
53 | ||
dcb84f33 VP |
54 | static int __cpuidle_register_device(struct cpuidle_device *dev); |
55 | ||
e1689795 RL |
56 | static inline int cpuidle_enter(struct cpuidle_device *dev, |
57 | struct cpuidle_driver *drv, int index) | |
58 | { | |
59 | struct cpuidle_state *target_state = &drv->states[index]; | |
60 | return target_state->enter(dev, drv, index); | |
61 | } | |
62 | ||
63 | static inline int cpuidle_enter_tk(struct cpuidle_device *dev, | |
64 | struct cpuidle_driver *drv, int index) | |
65 | { | |
66 | return cpuidle_wrap_enter(dev, drv, index, cpuidle_enter); | |
67 | } | |
68 | ||
69 | typedef int (*cpuidle_enter_t)(struct cpuidle_device *dev, | |
70 | struct cpuidle_driver *drv, int index); | |
71 | ||
72 | static cpuidle_enter_t cpuidle_enter_ops; | |
73 | ||
1a022e3f BO |
74 | /** |
75 | * cpuidle_play_dead - cpu off-lining | |
76 | * | |
ee01e663 | 77 | * Returns in case of an error or no driver |
1a022e3f BO |
78 | */ |
79 | int cpuidle_play_dead(void) | |
80 | { | |
81 | struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); | |
82 | struct cpuidle_driver *drv = cpuidle_get_driver(); | |
83 | int i, dead_state = -1; | |
84 | int power_usage = -1; | |
85 | ||
ee01e663 TK |
86 | if (!drv) |
87 | return -ENODEV; | |
88 | ||
1a022e3f BO |
89 | /* Find lowest-power state that supports long-term idle */ |
90 | for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) { | |
91 | struct cpuidle_state *s = &drv->states[i]; | |
92 | ||
93 | if (s->power_usage < power_usage && s->enter_dead) { | |
94 | power_usage = s->power_usage; | |
95 | dead_state = i; | |
96 | } | |
97 | } | |
98 | ||
99 | if (dead_state != -1) | |
100 | return drv->states[dead_state].enter_dead(dev, dead_state); | |
101 | ||
102 | return -ENODEV; | |
103 | } | |
104 | ||
56cfbf74 CC |
105 | /** |
106 | * cpuidle_enter_state - enter the state and update stats | |
107 | * @dev: cpuidle device for this cpu | |
108 | * @drv: cpuidle driver for this cpu | |
109 | * @next_state: index into drv->states of the state to enter | |
110 | */ | |
111 | int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, | |
112 | int next_state) | |
113 | { | |
114 | int entered_state; | |
115 | ||
116 | entered_state = cpuidle_enter_ops(dev, drv, next_state); | |
117 | ||
118 | if (entered_state >= 0) { | |
119 | /* Update cpuidle counters */ | |
120 | /* This can be moved to within driver enter routine | |
121 | * but that results in multiple copies of same code. | |
122 | */ | |
123 | dev->states_usage[entered_state].time += | |
124 | (unsigned long long)dev->last_residency; | |
125 | dev->states_usage[entered_state].usage++; | |
126 | } else { | |
127 | dev->last_residency = 0; | |
128 | } | |
129 | ||
130 | return entered_state; | |
131 | } | |
132 | ||
4f86d3a8 LB |
133 | /** |
134 | * cpuidle_idle_call - the main idle loop | |
135 | * | |
136 | * NOTE: no locks or semaphores should be used here | |
a0bfa137 | 137 | * return non-zero on failure |
4f86d3a8 | 138 | */ |
a0bfa137 | 139 | int cpuidle_idle_call(void) |
4f86d3a8 | 140 | { |
4a6f4fe8 | 141 | struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); |
46bcfad7 | 142 | struct cpuidle_driver *drv = cpuidle_get_driver(); |
e978aa7d | 143 | int next_state, entered_state; |
4f86d3a8 | 144 | |
a0bfa137 LB |
145 | if (off) |
146 | return -ENODEV; | |
147 | ||
148 | if (!initialized) | |
149 | return -ENODEV; | |
150 | ||
4f86d3a8 | 151 | /* check if the device is ready */ |
a0bfa137 LB |
152 | if (!dev || !dev->enabled) |
153 | return -EBUSY; | |
4f86d3a8 | 154 | |
9a655837 AV |
155 | #if 0 |
156 | /* shows regressions, re-enable for 2.6.29 */ | |
2e94d1f7 AV |
157 | /* |
158 | * run any timers that can be run now, at this point | |
159 | * before calculating the idle duration etc. | |
160 | */ | |
161 | hrtimer_peek_ahead_timers(); | |
9a655837 | 162 | #endif |
71abbbf8 | 163 | |
4f86d3a8 | 164 | /* ask the governor for the next state */ |
46bcfad7 | 165 | next_state = cpuidle_curr_governor->select(drv, dev); |
246eb7f0 KH |
166 | if (need_resched()) { |
167 | local_irq_enable(); | |
a0bfa137 | 168 | return 0; |
246eb7f0 KH |
169 | } |
170 | ||
76027ea8 SR |
171 | trace_power_start_rcuidle(POWER_CSTATE, next_state, dev->cpu); |
172 | trace_cpu_idle_rcuidle(next_state, dev->cpu); | |
f77cfe4e | 173 | |
56cfbf74 | 174 | entered_state = cpuidle_enter_state(dev, drv, next_state); |
f77cfe4e | 175 | |
76027ea8 SR |
176 | trace_power_end_rcuidle(dev->cpu); |
177 | trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu); | |
f77cfe4e | 178 | |
4f86d3a8 LB |
179 | /* give the governor an opportunity to reflect on the outcome */ |
180 | if (cpuidle_curr_governor->reflect) | |
e978aa7d | 181 | cpuidle_curr_governor->reflect(dev, entered_state); |
a0bfa137 LB |
182 | |
183 | return 0; | |
4f86d3a8 LB |
184 | } |
185 | ||
186 | /** | |
187 | * cpuidle_install_idle_handler - installs the cpuidle idle loop handler | |
188 | */ | |
189 | void cpuidle_install_idle_handler(void) | |
190 | { | |
a0bfa137 | 191 | if (enabled_devices) { |
4f86d3a8 LB |
192 | /* Make sure all changes finished before we switch to new idle */ |
193 | smp_wmb(); | |
a0bfa137 | 194 | initialized = 1; |
4f86d3a8 LB |
195 | } |
196 | } | |
197 | ||
198 | /** | |
199 | * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler | |
200 | */ | |
201 | void cpuidle_uninstall_idle_handler(void) | |
202 | { | |
a0bfa137 LB |
203 | if (enabled_devices) { |
204 | initialized = 0; | |
a6869cc4 | 205 | cpuidle_kick_cpus(); |
4f86d3a8 LB |
206 | } |
207 | } | |
208 | ||
209 | /** | |
210 | * cpuidle_pause_and_lock - temporarily disables CPUIDLE | |
211 | */ | |
212 | void cpuidle_pause_and_lock(void) | |
213 | { | |
214 | mutex_lock(&cpuidle_lock); | |
215 | cpuidle_uninstall_idle_handler(); | |
216 | } | |
217 | ||
218 | EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock); | |
219 | ||
220 | /** | |
221 | * cpuidle_resume_and_unlock - resumes CPUIDLE operation | |
222 | */ | |
223 | void cpuidle_resume_and_unlock(void) | |
224 | { | |
225 | cpuidle_install_idle_handler(); | |
226 | mutex_unlock(&cpuidle_lock); | |
227 | } | |
228 | ||
229 | EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock); | |
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; |
3a53396b | 295 | state->disable = 0; |
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 LB |
312 | |
313 | if (dev->enabled) | |
314 | return 0; | |
e1689795 | 315 | if (!drv || !cpuidle_curr_governor) |
4f86d3a8 LB |
316 | return -EIO; |
317 | if (!dev->state_count) | |
fc850f39 | 318 | dev->state_count = drv->state_count; |
4f86d3a8 | 319 | |
dcb84f33 VP |
320 | if (dev->registered == 0) { |
321 | ret = __cpuidle_register_device(dev); | |
322 | if (ret) | |
323 | return ret; | |
324 | } | |
325 | ||
e1689795 RL |
326 | cpuidle_enter_ops = drv->en_core_tk_irqen ? |
327 | cpuidle_enter_tk : cpuidle_enter; | |
328 | ||
329 | poll_idle_init(drv); | |
d8c216cf | 330 | |
4f86d3a8 LB |
331 | if ((ret = cpuidle_add_state_sysfs(dev))) |
332 | return ret; | |
333 | ||
334 | if (cpuidle_curr_governor->enable && | |
e1689795 | 335 | (ret = cpuidle_curr_governor->enable(drv, dev))) |
4f86d3a8 LB |
336 | goto fail_sysfs; |
337 | ||
338 | for (i = 0; i < dev->state_count; i++) { | |
4202735e DD |
339 | dev->states_usage[i].usage = 0; |
340 | dev->states_usage[i].time = 0; | |
4f86d3a8 LB |
341 | } |
342 | dev->last_residency = 0; | |
4f86d3a8 LB |
343 | |
344 | smp_wmb(); | |
345 | ||
346 | dev->enabled = 1; | |
347 | ||
348 | enabled_devices++; | |
349 | return 0; | |
350 | ||
351 | fail_sysfs: | |
352 | cpuidle_remove_state_sysfs(dev); | |
353 | ||
354 | return ret; | |
355 | } | |
356 | ||
357 | EXPORT_SYMBOL_GPL(cpuidle_enable_device); | |
358 | ||
359 | /** | |
360 | * cpuidle_disable_device - disables idle PM for a CPU | |
361 | * @dev: the CPU | |
362 | * | |
363 | * This function must be called between cpuidle_pause_and_lock and | |
364 | * cpuidle_resume_and_unlock when used externally. | |
365 | */ | |
366 | void cpuidle_disable_device(struct cpuidle_device *dev) | |
367 | { | |
368 | if (!dev->enabled) | |
369 | return; | |
752138df | 370 | if (!cpuidle_get_driver() || !cpuidle_curr_governor) |
4f86d3a8 LB |
371 | return; |
372 | ||
373 | dev->enabled = 0; | |
374 | ||
375 | if (cpuidle_curr_governor->disable) | |
46bcfad7 | 376 | cpuidle_curr_governor->disable(cpuidle_get_driver(), dev); |
4f86d3a8 LB |
377 | |
378 | cpuidle_remove_state_sysfs(dev); | |
379 | enabled_devices--; | |
380 | } | |
381 | ||
382 | EXPORT_SYMBOL_GPL(cpuidle_disable_device); | |
383 | ||
384 | /** | |
dcb84f33 VP |
385 | * __cpuidle_register_device - internal register function called before register |
386 | * and enable routines | |
4f86d3a8 | 387 | * @dev: the cpu |
dcb84f33 VP |
388 | * |
389 | * cpuidle_lock mutex must be held before this is called | |
4f86d3a8 | 390 | */ |
dcb84f33 | 391 | static int __cpuidle_register_device(struct cpuidle_device *dev) |
4f86d3a8 LB |
392 | { |
393 | int ret; | |
8a25a2fd | 394 | struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu); |
752138df | 395 | struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver(); |
4f86d3a8 | 396 | |
8a25a2fd | 397 | if (!dev) |
4f86d3a8 | 398 | return -EINVAL; |
752138df | 399 | if (!try_module_get(cpuidle_driver->owner)) |
4f86d3a8 LB |
400 | return -EINVAL; |
401 | ||
402 | init_completion(&dev->kobj_unregister); | |
403 | ||
4f86d3a8 LB |
404 | per_cpu(cpuidle_devices, dev->cpu) = dev; |
405 | list_add(&dev->device_list, &cpuidle_detected_devices); | |
3af272ab CC |
406 | ret = cpuidle_add_sysfs(cpu_dev); |
407 | if (ret) | |
408 | goto err_sysfs; | |
4f86d3a8 | 409 | |
dcb84f33 VP |
410 | dev->registered = 1; |
411 | return 0; | |
3af272ab CC |
412 | |
413 | err_sysfs: | |
414 | list_del(&dev->device_list); | |
415 | per_cpu(cpuidle_devices, dev->cpu) = NULL; | |
416 | module_put(cpuidle_driver->owner); | |
417 | return ret; | |
dcb84f33 VP |
418 | } |
419 | ||
420 | /** | |
421 | * cpuidle_register_device - registers a CPU's idle PM feature | |
422 | * @dev: the cpu | |
423 | */ | |
424 | int cpuidle_register_device(struct cpuidle_device *dev) | |
425 | { | |
426 | int ret; | |
427 | ||
428 | mutex_lock(&cpuidle_lock); | |
429 | ||
430 | if ((ret = __cpuidle_register_device(dev))) { | |
431 | mutex_unlock(&cpuidle_lock); | |
432 | return ret; | |
433 | } | |
434 | ||
4f86d3a8 LB |
435 | cpuidle_enable_device(dev); |
436 | cpuidle_install_idle_handler(); | |
437 | ||
438 | mutex_unlock(&cpuidle_lock); | |
439 | ||
440 | return 0; | |
441 | ||
442 | } | |
443 | ||
444 | EXPORT_SYMBOL_GPL(cpuidle_register_device); | |
445 | ||
446 | /** | |
447 | * cpuidle_unregister_device - unregisters a CPU's idle PM feature | |
448 | * @dev: the cpu | |
449 | */ | |
450 | void cpuidle_unregister_device(struct cpuidle_device *dev) | |
451 | { | |
8a25a2fd | 452 | struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu); |
752138df | 453 | struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver(); |
4f86d3a8 | 454 | |
dcb84f33 VP |
455 | if (dev->registered == 0) |
456 | return; | |
457 | ||
4f86d3a8 LB |
458 | cpuidle_pause_and_lock(); |
459 | ||
460 | cpuidle_disable_device(dev); | |
461 | ||
8a25a2fd | 462 | cpuidle_remove_sysfs(cpu_dev); |
4f86d3a8 LB |
463 | list_del(&dev->device_list); |
464 | wait_for_completion(&dev->kobj_unregister); | |
465 | per_cpu(cpuidle_devices, dev->cpu) = NULL; | |
466 | ||
467 | cpuidle_resume_and_unlock(); | |
468 | ||
752138df | 469 | module_put(cpuidle_driver->owner); |
4f86d3a8 LB |
470 | } |
471 | ||
472 | EXPORT_SYMBOL_GPL(cpuidle_unregister_device); | |
473 | ||
474 | #ifdef CONFIG_SMP | |
475 | ||
476 | static void smp_callback(void *v) | |
477 | { | |
478 | /* we already woke the CPU up, nothing more to do */ | |
479 | } | |
480 | ||
481 | /* | |
482 | * This function gets called when a part of the kernel has a new latency | |
483 | * requirement. This means we need to get all processors out of their C-state, | |
484 | * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that | |
485 | * wakes them all right up. | |
486 | */ | |
487 | static int cpuidle_latency_notify(struct notifier_block *b, | |
488 | unsigned long l, void *v) | |
489 | { | |
8691e5a8 | 490 | smp_call_function(smp_callback, NULL, 1); |
4f86d3a8 LB |
491 | return NOTIFY_OK; |
492 | } | |
493 | ||
494 | static struct notifier_block cpuidle_latency_notifier = { | |
495 | .notifier_call = cpuidle_latency_notify, | |
496 | }; | |
497 | ||
d82b3518 MG |
498 | static inline void latency_notifier_init(struct notifier_block *n) |
499 | { | |
500 | pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n); | |
501 | } | |
4f86d3a8 LB |
502 | |
503 | #else /* CONFIG_SMP */ | |
504 | ||
505 | #define latency_notifier_init(x) do { } while (0) | |
506 | ||
507 | #endif /* CONFIG_SMP */ | |
508 | ||
509 | /** | |
510 | * cpuidle_init - core initializer | |
511 | */ | |
512 | static int __init cpuidle_init(void) | |
513 | { | |
514 | int ret; | |
515 | ||
62027aea LB |
516 | if (cpuidle_disabled()) |
517 | return -ENODEV; | |
518 | ||
8a25a2fd | 519 | ret = cpuidle_add_interface(cpu_subsys.dev_root); |
4f86d3a8 LB |
520 | if (ret) |
521 | return ret; | |
522 | ||
523 | latency_notifier_init(&cpuidle_latency_notifier); | |
524 | ||
525 | return 0; | |
526 | } | |
527 | ||
62027aea | 528 | module_param(off, int, 0444); |
4f86d3a8 | 529 | core_initcall(cpuidle_init); |