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 | |
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 | ||
4f86d3a8 LB |
105 | /** |
106 | * cpuidle_idle_call - the main idle loop | |
107 | * | |
108 | * NOTE: no locks or semaphores should be used here | |
a0bfa137 | 109 | * return non-zero on failure |
4f86d3a8 | 110 | */ |
a0bfa137 | 111 | int cpuidle_idle_call(void) |
4f86d3a8 | 112 | { |
4a6f4fe8 | 113 | struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); |
46bcfad7 | 114 | struct cpuidle_driver *drv = cpuidle_get_driver(); |
e978aa7d | 115 | int next_state, entered_state; |
4f86d3a8 | 116 | |
a0bfa137 LB |
117 | if (off) |
118 | return -ENODEV; | |
119 | ||
120 | if (!initialized) | |
121 | return -ENODEV; | |
122 | ||
4f86d3a8 | 123 | /* check if the device is ready */ |
a0bfa137 LB |
124 | if (!dev || !dev->enabled) |
125 | return -EBUSY; | |
4f86d3a8 | 126 | |
9a655837 AV |
127 | #if 0 |
128 | /* shows regressions, re-enable for 2.6.29 */ | |
2e94d1f7 AV |
129 | /* |
130 | * run any timers that can be run now, at this point | |
131 | * before calculating the idle duration etc. | |
132 | */ | |
133 | hrtimer_peek_ahead_timers(); | |
9a655837 | 134 | #endif |
71abbbf8 | 135 | |
4f86d3a8 | 136 | /* ask the governor for the next state */ |
46bcfad7 | 137 | next_state = cpuidle_curr_governor->select(drv, dev); |
246eb7f0 KH |
138 | if (need_resched()) { |
139 | local_irq_enable(); | |
a0bfa137 | 140 | return 0; |
246eb7f0 KH |
141 | } |
142 | ||
76027ea8 SR |
143 | trace_power_start_rcuidle(POWER_CSTATE, next_state, dev->cpu); |
144 | trace_cpu_idle_rcuidle(next_state, dev->cpu); | |
f77cfe4e | 145 | |
e1689795 | 146 | entered_state = cpuidle_enter_ops(dev, drv, next_state); |
f77cfe4e | 147 | |
76027ea8 SR |
148 | trace_power_end_rcuidle(dev->cpu); |
149 | trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu); | |
f77cfe4e | 150 | |
e978aa7d DD |
151 | if (entered_state >= 0) { |
152 | /* Update cpuidle counters */ | |
153 | /* This can be moved to within driver enter routine | |
154 | * but that results in multiple copies of same code. | |
155 | */ | |
4202735e | 156 | dev->states_usage[entered_state].time += |
e978aa7d | 157 | (unsigned long long)dev->last_residency; |
4202735e | 158 | dev->states_usage[entered_state].usage++; |
e1689795 RL |
159 | } else { |
160 | dev->last_residency = 0; | |
e978aa7d | 161 | } |
4f86d3a8 LB |
162 | |
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; | |
a6869cc4 | 189 | cpuidle_kick_cpus(); |
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 | ||
e1689795 RL |
215 | /** |
216 | * cpuidle_wrap_enter - performs timekeeping and irqen around enter function | |
217 | * @dev: pointer to a valid cpuidle_device object | |
218 | * @drv: pointer to a valid cpuidle_driver object | |
219 | * @index: index of the target cpuidle state. | |
220 | */ | |
221 | int cpuidle_wrap_enter(struct cpuidle_device *dev, | |
222 | struct cpuidle_driver *drv, int index, | |
223 | int (*enter)(struct cpuidle_device *dev, | |
224 | struct cpuidle_driver *drv, int index)) | |
225 | { | |
226 | ktime_t time_start, time_end; | |
227 | s64 diff; | |
228 | ||
229 | time_start = ktime_get(); | |
230 | ||
231 | index = enter(dev, drv, index); | |
232 | ||
233 | time_end = ktime_get(); | |
234 | ||
235 | local_irq_enable(); | |
236 | ||
237 | diff = ktime_to_us(ktime_sub(time_end, time_start)); | |
238 | if (diff > INT_MAX) | |
239 | diff = INT_MAX; | |
240 | ||
241 | dev->last_residency = (int) diff; | |
242 | ||
243 | return index; | |
244 | } | |
245 | ||
d8c216cf | 246 | #ifdef CONFIG_ARCH_HAS_CPU_RELAX |
46bcfad7 DD |
247 | static int poll_idle(struct cpuidle_device *dev, |
248 | struct cpuidle_driver *drv, int index) | |
d8c216cf RW |
249 | { |
250 | ktime_t t1, t2; | |
251 | s64 diff; | |
d8c216cf RW |
252 | |
253 | t1 = ktime_get(); | |
254 | local_irq_enable(); | |
255 | while (!need_resched()) | |
256 | cpu_relax(); | |
257 | ||
258 | t2 = ktime_get(); | |
259 | diff = ktime_to_us(ktime_sub(t2, t1)); | |
260 | if (diff > INT_MAX) | |
261 | diff = INT_MAX; | |
262 | ||
e978aa7d DD |
263 | dev->last_residency = (int) diff; |
264 | ||
265 | return index; | |
d8c216cf RW |
266 | } |
267 | ||
46bcfad7 | 268 | static void poll_idle_init(struct cpuidle_driver *drv) |
d8c216cf | 269 | { |
46bcfad7 | 270 | struct cpuidle_state *state = &drv->states[0]; |
d8c216cf | 271 | |
720f1c30 | 272 | snprintf(state->name, CPUIDLE_NAME_LEN, "POLL"); |
d8c216cf RW |
273 | snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE"); |
274 | state->exit_latency = 0; | |
275 | state->target_residency = 0; | |
276 | state->power_usage = -1; | |
d247632c | 277 | state->flags = 0; |
d8c216cf | 278 | state->enter = poll_idle; |
3a53396b | 279 | state->disable = 0; |
d8c216cf RW |
280 | } |
281 | #else | |
46bcfad7 | 282 | static void poll_idle_init(struct cpuidle_driver *drv) {} |
d8c216cf RW |
283 | #endif /* CONFIG_ARCH_HAS_CPU_RELAX */ |
284 | ||
4f86d3a8 LB |
285 | /** |
286 | * cpuidle_enable_device - enables idle PM for a CPU | |
287 | * @dev: the CPU | |
288 | * | |
289 | * This function must be called between cpuidle_pause_and_lock and | |
290 | * cpuidle_resume_and_unlock when used externally. | |
291 | */ | |
292 | int cpuidle_enable_device(struct cpuidle_device *dev) | |
293 | { | |
294 | int ret, i; | |
e1689795 | 295 | struct cpuidle_driver *drv = cpuidle_get_driver(); |
4f86d3a8 LB |
296 | |
297 | if (dev->enabled) | |
298 | return 0; | |
e1689795 | 299 | if (!drv || !cpuidle_curr_governor) |
4f86d3a8 LB |
300 | return -EIO; |
301 | if (!dev->state_count) | |
fc850f39 | 302 | dev->state_count = drv->state_count; |
4f86d3a8 | 303 | |
dcb84f33 VP |
304 | if (dev->registered == 0) { |
305 | ret = __cpuidle_register_device(dev); | |
306 | if (ret) | |
307 | return ret; | |
308 | } | |
309 | ||
e1689795 RL |
310 | cpuidle_enter_ops = drv->en_core_tk_irqen ? |
311 | cpuidle_enter_tk : cpuidle_enter; | |
312 | ||
313 | poll_idle_init(drv); | |
d8c216cf | 314 | |
4f86d3a8 LB |
315 | if ((ret = cpuidle_add_state_sysfs(dev))) |
316 | return ret; | |
317 | ||
318 | if (cpuidle_curr_governor->enable && | |
e1689795 | 319 | (ret = cpuidle_curr_governor->enable(drv, dev))) |
4f86d3a8 LB |
320 | goto fail_sysfs; |
321 | ||
322 | for (i = 0; i < dev->state_count; i++) { | |
4202735e DD |
323 | dev->states_usage[i].usage = 0; |
324 | dev->states_usage[i].time = 0; | |
4f86d3a8 LB |
325 | } |
326 | dev->last_residency = 0; | |
4f86d3a8 LB |
327 | |
328 | smp_wmb(); | |
329 | ||
330 | dev->enabled = 1; | |
331 | ||
332 | enabled_devices++; | |
333 | return 0; | |
334 | ||
335 | fail_sysfs: | |
336 | cpuidle_remove_state_sysfs(dev); | |
337 | ||
338 | return ret; | |
339 | } | |
340 | ||
341 | EXPORT_SYMBOL_GPL(cpuidle_enable_device); | |
342 | ||
343 | /** | |
344 | * cpuidle_disable_device - disables idle PM for a CPU | |
345 | * @dev: the CPU | |
346 | * | |
347 | * This function must be called between cpuidle_pause_and_lock and | |
348 | * cpuidle_resume_and_unlock when used externally. | |
349 | */ | |
350 | void cpuidle_disable_device(struct cpuidle_device *dev) | |
351 | { | |
352 | if (!dev->enabled) | |
353 | return; | |
752138df | 354 | if (!cpuidle_get_driver() || !cpuidle_curr_governor) |
4f86d3a8 LB |
355 | return; |
356 | ||
357 | dev->enabled = 0; | |
358 | ||
359 | if (cpuidle_curr_governor->disable) | |
46bcfad7 | 360 | cpuidle_curr_governor->disable(cpuidle_get_driver(), dev); |
4f86d3a8 LB |
361 | |
362 | cpuidle_remove_state_sysfs(dev); | |
363 | enabled_devices--; | |
364 | } | |
365 | ||
366 | EXPORT_SYMBOL_GPL(cpuidle_disable_device); | |
367 | ||
368 | /** | |
dcb84f33 VP |
369 | * __cpuidle_register_device - internal register function called before register |
370 | * and enable routines | |
4f86d3a8 | 371 | * @dev: the cpu |
dcb84f33 VP |
372 | * |
373 | * cpuidle_lock mutex must be held before this is called | |
4f86d3a8 | 374 | */ |
dcb84f33 | 375 | static int __cpuidle_register_device(struct cpuidle_device *dev) |
4f86d3a8 LB |
376 | { |
377 | int ret; | |
8a25a2fd | 378 | struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu); |
752138df | 379 | struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver(); |
4f86d3a8 | 380 | |
8a25a2fd | 381 | if (!dev) |
4f86d3a8 | 382 | return -EINVAL; |
752138df | 383 | if (!try_module_get(cpuidle_driver->owner)) |
4f86d3a8 LB |
384 | return -EINVAL; |
385 | ||
386 | init_completion(&dev->kobj_unregister); | |
387 | ||
4f86d3a8 LB |
388 | per_cpu(cpuidle_devices, dev->cpu) = dev; |
389 | list_add(&dev->device_list, &cpuidle_detected_devices); | |
8a25a2fd | 390 | if ((ret = cpuidle_add_sysfs(cpu_dev))) { |
752138df | 391 | module_put(cpuidle_driver->owner); |
4f86d3a8 LB |
392 | return ret; |
393 | } | |
394 | ||
dcb84f33 VP |
395 | dev->registered = 1; |
396 | return 0; | |
397 | } | |
398 | ||
399 | /** | |
400 | * cpuidle_register_device - registers a CPU's idle PM feature | |
401 | * @dev: the cpu | |
402 | */ | |
403 | int cpuidle_register_device(struct cpuidle_device *dev) | |
404 | { | |
405 | int ret; | |
406 | ||
407 | mutex_lock(&cpuidle_lock); | |
408 | ||
409 | if ((ret = __cpuidle_register_device(dev))) { | |
410 | mutex_unlock(&cpuidle_lock); | |
411 | return ret; | |
412 | } | |
413 | ||
4f86d3a8 LB |
414 | cpuidle_enable_device(dev); |
415 | cpuidle_install_idle_handler(); | |
416 | ||
417 | mutex_unlock(&cpuidle_lock); | |
418 | ||
419 | return 0; | |
420 | ||
421 | } | |
422 | ||
423 | EXPORT_SYMBOL_GPL(cpuidle_register_device); | |
424 | ||
425 | /** | |
426 | * cpuidle_unregister_device - unregisters a CPU's idle PM feature | |
427 | * @dev: the cpu | |
428 | */ | |
429 | void cpuidle_unregister_device(struct cpuidle_device *dev) | |
430 | { | |
8a25a2fd | 431 | struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu); |
752138df | 432 | struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver(); |
4f86d3a8 | 433 | |
dcb84f33 VP |
434 | if (dev->registered == 0) |
435 | return; | |
436 | ||
4f86d3a8 LB |
437 | cpuidle_pause_and_lock(); |
438 | ||
439 | cpuidle_disable_device(dev); | |
440 | ||
8a25a2fd | 441 | cpuidle_remove_sysfs(cpu_dev); |
4f86d3a8 LB |
442 | list_del(&dev->device_list); |
443 | wait_for_completion(&dev->kobj_unregister); | |
444 | per_cpu(cpuidle_devices, dev->cpu) = NULL; | |
445 | ||
446 | cpuidle_resume_and_unlock(); | |
447 | ||
752138df | 448 | module_put(cpuidle_driver->owner); |
4f86d3a8 LB |
449 | } |
450 | ||
451 | EXPORT_SYMBOL_GPL(cpuidle_unregister_device); | |
452 | ||
453 | #ifdef CONFIG_SMP | |
454 | ||
455 | static void smp_callback(void *v) | |
456 | { | |
457 | /* we already woke the CPU up, nothing more to do */ | |
458 | } | |
459 | ||
460 | /* | |
461 | * This function gets called when a part of the kernel has a new latency | |
462 | * requirement. This means we need to get all processors out of their C-state, | |
463 | * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that | |
464 | * wakes them all right up. | |
465 | */ | |
466 | static int cpuidle_latency_notify(struct notifier_block *b, | |
467 | unsigned long l, void *v) | |
468 | { | |
8691e5a8 | 469 | smp_call_function(smp_callback, NULL, 1); |
4f86d3a8 LB |
470 | return NOTIFY_OK; |
471 | } | |
472 | ||
473 | static struct notifier_block cpuidle_latency_notifier = { | |
474 | .notifier_call = cpuidle_latency_notify, | |
475 | }; | |
476 | ||
d82b3518 MG |
477 | static inline void latency_notifier_init(struct notifier_block *n) |
478 | { | |
479 | pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n); | |
480 | } | |
4f86d3a8 LB |
481 | |
482 | #else /* CONFIG_SMP */ | |
483 | ||
484 | #define latency_notifier_init(x) do { } while (0) | |
485 | ||
486 | #endif /* CONFIG_SMP */ | |
487 | ||
488 | /** | |
489 | * cpuidle_init - core initializer | |
490 | */ | |
491 | static int __init cpuidle_init(void) | |
492 | { | |
493 | int ret; | |
494 | ||
62027aea LB |
495 | if (cpuidle_disabled()) |
496 | return -ENODEV; | |
497 | ||
8a25a2fd | 498 | ret = cpuidle_add_interface(cpu_subsys.dev_root); |
4f86d3a8 LB |
499 | if (ret) |
500 | return ret; | |
501 | ||
502 | latency_notifier_init(&cpuidle_latency_notifier); | |
503 | ||
504 | return 0; | |
505 | } | |
506 | ||
62027aea | 507 | module_param(off, int, 0444); |
4f86d3a8 | 508 | core_initcall(cpuidle_init); |