Commit | Line | Data |
---|---|---|
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); | |
bf4d1b5d | 71 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
8aef33a7 | 72 | int i; |
1a022e3f | 73 | |
ee01e663 TK |
74 | if (!drv) |
75 | return -ENODEV; | |
76 | ||
1a022e3f | 77 | /* Find lowest-power state that supports long-term idle */ |
8aef33a7 DL |
78 | for (i = drv->state_count - 1; i >= CPUIDLE_DRIVER_STATE_START; i--) |
79 | if (drv->states[i].enter_dead) | |
80 | return drv->states[i].enter_dead(dev, i); | |
1a022e3f BO |
81 | |
82 | return -ENODEV; | |
83 | } | |
84 | ||
56cfbf74 CC |
85 | /** |
86 | * cpuidle_enter_state - enter the state and update stats | |
87 | * @dev: cpuidle device for this cpu | |
88 | * @drv: cpuidle driver for this cpu | |
89 | * @next_state: index into drv->states of the state to enter | |
90 | */ | |
91 | int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, | |
92 | int next_state) | |
93 | { | |
94 | int entered_state; | |
95 | ||
96 | entered_state = cpuidle_enter_ops(dev, drv, next_state); | |
97 | ||
98 | if (entered_state >= 0) { | |
99 | /* Update cpuidle counters */ | |
100 | /* This can be moved to within driver enter routine | |
101 | * but that results in multiple copies of same code. | |
102 | */ | |
a474a515 | 103 | dev->states_usage[entered_state].time += dev->last_residency; |
56cfbf74 CC |
104 | dev->states_usage[entered_state].usage++; |
105 | } else { | |
106 | dev->last_residency = 0; | |
107 | } | |
108 | ||
109 | return entered_state; | |
110 | } | |
111 | ||
4f86d3a8 LB |
112 | /** |
113 | * cpuidle_idle_call - the main idle loop | |
114 | * | |
115 | * NOTE: no locks or semaphores should be used here | |
a0bfa137 | 116 | * return non-zero on failure |
4f86d3a8 | 117 | */ |
a0bfa137 | 118 | int cpuidle_idle_call(void) |
4f86d3a8 | 119 | { |
4a6f4fe8 | 120 | struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); |
bf4d1b5d | 121 | struct cpuidle_driver *drv; |
e978aa7d | 122 | int next_state, entered_state; |
4f86d3a8 | 123 | |
a0bfa137 LB |
124 | if (off) |
125 | return -ENODEV; | |
126 | ||
127 | if (!initialized) | |
128 | return -ENODEV; | |
129 | ||
4f86d3a8 | 130 | /* check if the device is ready */ |
a0bfa137 LB |
131 | if (!dev || !dev->enabled) |
132 | return -EBUSY; | |
4f86d3a8 | 133 | |
bf4d1b5d DL |
134 | drv = cpuidle_get_cpu_driver(dev); |
135 | ||
4f86d3a8 | 136 | /* ask the governor for the next state */ |
46bcfad7 | 137 | next_state = cpuidle_curr_governor->select(drv, dev); |
246eb7f0 | 138 | if (need_resched()) { |
d73d68dc YS |
139 | dev->last_residency = 0; |
140 | /* give the governor an opportunity to reflect on the outcome */ | |
141 | if (cpuidle_curr_governor->reflect) | |
142 | cpuidle_curr_governor->reflect(dev, next_state); | |
246eb7f0 | 143 | local_irq_enable(); |
a0bfa137 | 144 | return 0; |
246eb7f0 KH |
145 | } |
146 | ||
76027ea8 SR |
147 | trace_power_start_rcuidle(POWER_CSTATE, next_state, dev->cpu); |
148 | trace_cpu_idle_rcuidle(next_state, dev->cpu); | |
f77cfe4e | 149 | |
4126c019 CC |
150 | if (cpuidle_state_is_coupled(dev, drv, next_state)) |
151 | entered_state = cpuidle_enter_state_coupled(dev, drv, | |
152 | next_state); | |
153 | else | |
154 | entered_state = cpuidle_enter_state(dev, drv, next_state); | |
f77cfe4e | 155 | |
76027ea8 SR |
156 | trace_power_end_rcuidle(dev->cpu); |
157 | trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu); | |
f77cfe4e | 158 | |
4f86d3a8 LB |
159 | /* give the governor an opportunity to reflect on the outcome */ |
160 | if (cpuidle_curr_governor->reflect) | |
e978aa7d | 161 | cpuidle_curr_governor->reflect(dev, entered_state); |
a0bfa137 LB |
162 | |
163 | return 0; | |
4f86d3a8 LB |
164 | } |
165 | ||
166 | /** | |
167 | * cpuidle_install_idle_handler - installs the cpuidle idle loop handler | |
168 | */ | |
169 | void cpuidle_install_idle_handler(void) | |
170 | { | |
a0bfa137 | 171 | if (enabled_devices) { |
4f86d3a8 LB |
172 | /* Make sure all changes finished before we switch to new idle */ |
173 | smp_wmb(); | |
a0bfa137 | 174 | initialized = 1; |
4f86d3a8 LB |
175 | } |
176 | } | |
177 | ||
178 | /** | |
179 | * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler | |
180 | */ | |
181 | void cpuidle_uninstall_idle_handler(void) | |
182 | { | |
a0bfa137 LB |
183 | if (enabled_devices) { |
184 | initialized = 0; | |
4a162513 | 185 | kick_all_cpus_sync(); |
4f86d3a8 LB |
186 | } |
187 | } | |
188 | ||
189 | /** | |
190 | * cpuidle_pause_and_lock - temporarily disables CPUIDLE | |
191 | */ | |
192 | void cpuidle_pause_and_lock(void) | |
193 | { | |
194 | mutex_lock(&cpuidle_lock); | |
195 | cpuidle_uninstall_idle_handler(); | |
196 | } | |
197 | ||
198 | EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock); | |
199 | ||
200 | /** | |
201 | * cpuidle_resume_and_unlock - resumes CPUIDLE operation | |
202 | */ | |
203 | void cpuidle_resume_and_unlock(void) | |
204 | { | |
205 | cpuidle_install_idle_handler(); | |
206 | mutex_unlock(&cpuidle_lock); | |
207 | } | |
208 | ||
209 | EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock); | |
210 | ||
8651f97b PM |
211 | /* Currently used in suspend/resume path to suspend cpuidle */ |
212 | void cpuidle_pause(void) | |
213 | { | |
214 | mutex_lock(&cpuidle_lock); | |
215 | cpuidle_uninstall_idle_handler(); | |
216 | mutex_unlock(&cpuidle_lock); | |
217 | } | |
218 | ||
219 | /* Currently used in suspend/resume path to resume cpuidle */ | |
220 | void cpuidle_resume(void) | |
221 | { | |
222 | mutex_lock(&cpuidle_lock); | |
223 | cpuidle_install_idle_handler(); | |
224 | mutex_unlock(&cpuidle_lock); | |
225 | } | |
226 | ||
e1689795 RL |
227 | /** |
228 | * cpuidle_wrap_enter - performs timekeeping and irqen around enter function | |
229 | * @dev: pointer to a valid cpuidle_device object | |
230 | * @drv: pointer to a valid cpuidle_driver object | |
231 | * @index: index of the target cpuidle state. | |
232 | */ | |
233 | int cpuidle_wrap_enter(struct cpuidle_device *dev, | |
234 | struct cpuidle_driver *drv, int index, | |
235 | int (*enter)(struct cpuidle_device *dev, | |
236 | struct cpuidle_driver *drv, int index)) | |
237 | { | |
238 | ktime_t time_start, time_end; | |
239 | s64 diff; | |
240 | ||
241 | time_start = ktime_get(); | |
242 | ||
243 | index = enter(dev, drv, index); | |
244 | ||
245 | time_end = ktime_get(); | |
246 | ||
247 | local_irq_enable(); | |
248 | ||
249 | diff = ktime_to_us(ktime_sub(time_end, time_start)); | |
250 | if (diff > INT_MAX) | |
251 | diff = INT_MAX; | |
252 | ||
253 | dev->last_residency = (int) diff; | |
254 | ||
255 | return index; | |
256 | } | |
257 | ||
d8c216cf | 258 | #ifdef CONFIG_ARCH_HAS_CPU_RELAX |
46bcfad7 DD |
259 | static int poll_idle(struct cpuidle_device *dev, |
260 | struct cpuidle_driver *drv, int index) | |
d8c216cf RW |
261 | { |
262 | ktime_t t1, t2; | |
263 | s64 diff; | |
d8c216cf RW |
264 | |
265 | t1 = ktime_get(); | |
266 | local_irq_enable(); | |
267 | while (!need_resched()) | |
268 | cpu_relax(); | |
269 | ||
270 | t2 = ktime_get(); | |
271 | diff = ktime_to_us(ktime_sub(t2, t1)); | |
272 | if (diff > INT_MAX) | |
273 | diff = INT_MAX; | |
274 | ||
e978aa7d DD |
275 | dev->last_residency = (int) diff; |
276 | ||
277 | return index; | |
d8c216cf RW |
278 | } |
279 | ||
46bcfad7 | 280 | static void poll_idle_init(struct cpuidle_driver *drv) |
d8c216cf | 281 | { |
46bcfad7 | 282 | struct cpuidle_state *state = &drv->states[0]; |
d8c216cf | 283 | |
720f1c30 | 284 | snprintf(state->name, CPUIDLE_NAME_LEN, "POLL"); |
d8c216cf RW |
285 | snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE"); |
286 | state->exit_latency = 0; | |
287 | state->target_residency = 0; | |
288 | state->power_usage = -1; | |
d247632c | 289 | state->flags = 0; |
d8c216cf | 290 | state->enter = poll_idle; |
cbc9ef02 | 291 | state->disabled = false; |
d8c216cf RW |
292 | } |
293 | #else | |
46bcfad7 | 294 | static void poll_idle_init(struct cpuidle_driver *drv) {} |
d8c216cf RW |
295 | #endif /* CONFIG_ARCH_HAS_CPU_RELAX */ |
296 | ||
4f86d3a8 LB |
297 | /** |
298 | * cpuidle_enable_device - enables idle PM for a CPU | |
299 | * @dev: the CPU | |
300 | * | |
301 | * This function must be called between cpuidle_pause_and_lock and | |
302 | * cpuidle_resume_and_unlock when used externally. | |
303 | */ | |
304 | int cpuidle_enable_device(struct cpuidle_device *dev) | |
305 | { | |
306 | int ret, i; | |
bf4d1b5d | 307 | struct cpuidle_driver *drv; |
4f86d3a8 | 308 | |
1b0a0e9a SB |
309 | if (!dev) |
310 | return -EINVAL; | |
311 | ||
4f86d3a8 LB |
312 | if (dev->enabled) |
313 | return 0; | |
bf4d1b5d DL |
314 | |
315 | drv = cpuidle_get_cpu_driver(dev); | |
316 | ||
e1689795 | 317 | if (!drv || !cpuidle_curr_governor) |
4f86d3a8 | 318 | return -EIO; |
bf4d1b5d | 319 | |
4f86d3a8 | 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 | |
bf4d1b5d DL |
334 | ret = cpuidle_add_device_sysfs(dev); |
335 | if (ret) | |
4f86d3a8 LB |
336 | return ret; |
337 | ||
338 | if (cpuidle_curr_governor->enable && | |
e1689795 | 339 | (ret = cpuidle_curr_governor->enable(drv, dev))) |
4f86d3a8 LB |
340 | goto fail_sysfs; |
341 | ||
342 | for (i = 0; i < dev->state_count; i++) { | |
4202735e DD |
343 | dev->states_usage[i].usage = 0; |
344 | dev->states_usage[i].time = 0; | |
4f86d3a8 LB |
345 | } |
346 | dev->last_residency = 0; | |
4f86d3a8 LB |
347 | |
348 | smp_wmb(); | |
349 | ||
350 | dev->enabled = 1; | |
351 | ||
352 | enabled_devices++; | |
353 | return 0; | |
354 | ||
355 | fail_sysfs: | |
bf4d1b5d | 356 | cpuidle_remove_device_sysfs(dev); |
4f86d3a8 LB |
357 | |
358 | return ret; | |
359 | } | |
360 | ||
361 | EXPORT_SYMBOL_GPL(cpuidle_enable_device); | |
362 | ||
363 | /** | |
364 | * cpuidle_disable_device - disables idle PM for a CPU | |
365 | * @dev: the CPU | |
366 | * | |
367 | * This function must be called between cpuidle_pause_and_lock and | |
368 | * cpuidle_resume_and_unlock when used externally. | |
369 | */ | |
370 | void cpuidle_disable_device(struct cpuidle_device *dev) | |
371 | { | |
bf4d1b5d DL |
372 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
373 | ||
cf31cd1a | 374 | if (!dev || !dev->enabled) |
4f86d3a8 | 375 | return; |
bf4d1b5d DL |
376 | |
377 | if (!drv || !cpuidle_curr_governor) | |
4f86d3a8 LB |
378 | return; |
379 | ||
380 | dev->enabled = 0; | |
381 | ||
382 | if (cpuidle_curr_governor->disable) | |
bf4d1b5d | 383 | cpuidle_curr_governor->disable(drv, dev); |
4f86d3a8 | 384 | |
bf4d1b5d | 385 | cpuidle_remove_device_sysfs(dev); |
4f86d3a8 LB |
386 | enabled_devices--; |
387 | } | |
388 | ||
389 | EXPORT_SYMBOL_GPL(cpuidle_disable_device); | |
390 | ||
391 | /** | |
dcb84f33 VP |
392 | * __cpuidle_register_device - internal register function called before register |
393 | * and enable routines | |
4f86d3a8 | 394 | * @dev: the cpu |
dcb84f33 VP |
395 | * |
396 | * cpuidle_lock mutex must be held before this is called | |
4f86d3a8 | 397 | */ |
dcb84f33 | 398 | static int __cpuidle_register_device(struct cpuidle_device *dev) |
4f86d3a8 LB |
399 | { |
400 | int ret; | |
bf4d1b5d | 401 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
4f86d3a8 | 402 | |
bf4d1b5d | 403 | if (!try_module_get(drv->owner)) |
4f86d3a8 LB |
404 | return -EINVAL; |
405 | ||
4f86d3a8 LB |
406 | per_cpu(cpuidle_devices, dev->cpu) = dev; |
407 | list_add(&dev->device_list, &cpuidle_detected_devices); | |
1aef40e2 | 408 | ret = cpuidle_add_sysfs(dev); |
3af272ab CC |
409 | if (ret) |
410 | goto err_sysfs; | |
4f86d3a8 | 411 | |
4126c019 CC |
412 | ret = cpuidle_coupled_register_device(dev); |
413 | if (ret) | |
414 | goto err_coupled; | |
4f86d3a8 | 415 | |
dcb84f33 VP |
416 | dev->registered = 1; |
417 | return 0; | |
3af272ab | 418 | |
4126c019 | 419 | err_coupled: |
1aef40e2 | 420 | cpuidle_remove_sysfs(dev); |
3af272ab CC |
421 | err_sysfs: |
422 | list_del(&dev->device_list); | |
423 | per_cpu(cpuidle_devices, dev->cpu) = NULL; | |
bf4d1b5d | 424 | module_put(drv->owner); |
3af272ab | 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 | { | |
bf4d1b5d | 463 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
4f86d3a8 | 464 | |
dcb84f33 VP |
465 | if (dev->registered == 0) |
466 | return; | |
467 | ||
4f86d3a8 LB |
468 | cpuidle_pause_and_lock(); |
469 | ||
470 | cpuidle_disable_device(dev); | |
471 | ||
1aef40e2 | 472 | cpuidle_remove_sysfs(dev); |
4f86d3a8 | 473 | list_del(&dev->device_list); |
4f86d3a8 LB |
474 | per_cpu(cpuidle_devices, dev->cpu) = NULL; |
475 | ||
4126c019 CC |
476 | cpuidle_coupled_unregister_device(dev); |
477 | ||
4f86d3a8 LB |
478 | cpuidle_resume_and_unlock(); |
479 | ||
bf4d1b5d | 480 | module_put(drv->owner); |
4f86d3a8 LB |
481 | } |
482 | ||
483 | EXPORT_SYMBOL_GPL(cpuidle_unregister_device); | |
484 | ||
485 | #ifdef CONFIG_SMP | |
486 | ||
487 | static void smp_callback(void *v) | |
488 | { | |
489 | /* we already woke the CPU up, nothing more to do */ | |
490 | } | |
491 | ||
492 | /* | |
493 | * This function gets called when a part of the kernel has a new latency | |
494 | * requirement. This means we need to get all processors out of their C-state, | |
495 | * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that | |
496 | * wakes them all right up. | |
497 | */ | |
498 | static int cpuidle_latency_notify(struct notifier_block *b, | |
499 | unsigned long l, void *v) | |
500 | { | |
8691e5a8 | 501 | smp_call_function(smp_callback, NULL, 1); |
4f86d3a8 LB |
502 | return NOTIFY_OK; |
503 | } | |
504 | ||
505 | static struct notifier_block cpuidle_latency_notifier = { | |
506 | .notifier_call = cpuidle_latency_notify, | |
507 | }; | |
508 | ||
d82b3518 MG |
509 | static inline void latency_notifier_init(struct notifier_block *n) |
510 | { | |
511 | pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n); | |
512 | } | |
4f86d3a8 LB |
513 | |
514 | #else /* CONFIG_SMP */ | |
515 | ||
516 | #define latency_notifier_init(x) do { } while (0) | |
517 | ||
518 | #endif /* CONFIG_SMP */ | |
519 | ||
520 | /** | |
521 | * cpuidle_init - core initializer | |
522 | */ | |
523 | static int __init cpuidle_init(void) | |
524 | { | |
525 | int ret; | |
526 | ||
62027aea LB |
527 | if (cpuidle_disabled()) |
528 | return -ENODEV; | |
529 | ||
8a25a2fd | 530 | ret = cpuidle_add_interface(cpu_subsys.dev_root); |
4f86d3a8 LB |
531 | if (ret) |
532 | return ret; | |
533 | ||
534 | latency_notifier_init(&cpuidle_latency_notifier); | |
535 | ||
536 | return 0; | |
537 | } | |
538 | ||
62027aea | 539 | module_param(off, int, 0444); |
4f86d3a8 | 540 | core_initcall(cpuidle_init); |