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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 | ||
4f86d3a8 LB |
94 | /** |
95 | * cpuidle_idle_call - the main idle loop | |
96 | * | |
97 | * NOTE: no locks or semaphores should be used here | |
a0bfa137 | 98 | * return non-zero on failure |
4f86d3a8 | 99 | */ |
a0bfa137 | 100 | int cpuidle_idle_call(void) |
4f86d3a8 | 101 | { |
4a6f4fe8 | 102 | struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); |
46bcfad7 | 103 | struct cpuidle_driver *drv = cpuidle_get_driver(); |
e978aa7d | 104 | int next_state, entered_state; |
4f86d3a8 | 105 | |
a0bfa137 LB |
106 | if (off) |
107 | return -ENODEV; | |
108 | ||
109 | if (!initialized) | |
110 | return -ENODEV; | |
111 | ||
4f86d3a8 | 112 | /* check if the device is ready */ |
a0bfa137 LB |
113 | if (!dev || !dev->enabled) |
114 | return -EBUSY; | |
4f86d3a8 | 115 | |
9a655837 AV |
116 | #if 0 |
117 | /* shows regressions, re-enable for 2.6.29 */ | |
2e94d1f7 AV |
118 | /* |
119 | * run any timers that can be run now, at this point | |
120 | * before calculating the idle duration etc. | |
121 | */ | |
122 | hrtimer_peek_ahead_timers(); | |
9a655837 | 123 | #endif |
71abbbf8 | 124 | |
4f86d3a8 | 125 | /* ask the governor for the next state */ |
46bcfad7 | 126 | next_state = cpuidle_curr_governor->select(drv, dev); |
246eb7f0 KH |
127 | if (need_resched()) { |
128 | local_irq_enable(); | |
a0bfa137 | 129 | return 0; |
246eb7f0 KH |
130 | } |
131 | ||
76027ea8 SR |
132 | trace_power_start_rcuidle(POWER_CSTATE, next_state, dev->cpu); |
133 | trace_cpu_idle_rcuidle(next_state, dev->cpu); | |
f77cfe4e | 134 | |
e1689795 | 135 | entered_state = cpuidle_enter_ops(dev, drv, next_state); |
f77cfe4e | 136 | |
76027ea8 SR |
137 | trace_power_end_rcuidle(dev->cpu); |
138 | trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu); | |
f77cfe4e | 139 | |
e978aa7d DD |
140 | if (entered_state >= 0) { |
141 | /* Update cpuidle counters */ | |
142 | /* This can be moved to within driver enter routine | |
143 | * but that results in multiple copies of same code. | |
144 | */ | |
4202735e | 145 | dev->states_usage[entered_state].time += |
e978aa7d | 146 | (unsigned long long)dev->last_residency; |
4202735e | 147 | dev->states_usage[entered_state].usage++; |
e1689795 RL |
148 | } else { |
149 | dev->last_residency = 0; | |
e978aa7d | 150 | } |
4f86d3a8 LB |
151 | |
152 | /* give the governor an opportunity to reflect on the outcome */ | |
153 | if (cpuidle_curr_governor->reflect) | |
e978aa7d | 154 | cpuidle_curr_governor->reflect(dev, entered_state); |
a0bfa137 LB |
155 | |
156 | return 0; | |
4f86d3a8 LB |
157 | } |
158 | ||
159 | /** | |
160 | * cpuidle_install_idle_handler - installs the cpuidle idle loop handler | |
161 | */ | |
162 | void cpuidle_install_idle_handler(void) | |
163 | { | |
a0bfa137 | 164 | if (enabled_devices) { |
4f86d3a8 LB |
165 | /* Make sure all changes finished before we switch to new idle */ |
166 | smp_wmb(); | |
a0bfa137 | 167 | initialized = 1; |
4f86d3a8 LB |
168 | } |
169 | } | |
170 | ||
171 | /** | |
172 | * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler | |
173 | */ | |
174 | void cpuidle_uninstall_idle_handler(void) | |
175 | { | |
a0bfa137 LB |
176 | if (enabled_devices) { |
177 | initialized = 0; | |
4a162513 | 178 | kick_all_cpus_sync(); |
4f86d3a8 LB |
179 | } |
180 | } | |
181 | ||
182 | /** | |
183 | * cpuidle_pause_and_lock - temporarily disables CPUIDLE | |
184 | */ | |
185 | void cpuidle_pause_and_lock(void) | |
186 | { | |
187 | mutex_lock(&cpuidle_lock); | |
188 | cpuidle_uninstall_idle_handler(); | |
189 | } | |
190 | ||
191 | EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock); | |
192 | ||
193 | /** | |
194 | * cpuidle_resume_and_unlock - resumes CPUIDLE operation | |
195 | */ | |
196 | void cpuidle_resume_and_unlock(void) | |
197 | { | |
198 | cpuidle_install_idle_handler(); | |
199 | mutex_unlock(&cpuidle_lock); | |
200 | } | |
201 | ||
202 | EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock); | |
203 | ||
e1689795 RL |
204 | /** |
205 | * cpuidle_wrap_enter - performs timekeeping and irqen around enter function | |
206 | * @dev: pointer to a valid cpuidle_device object | |
207 | * @drv: pointer to a valid cpuidle_driver object | |
208 | * @index: index of the target cpuidle state. | |
209 | */ | |
210 | int cpuidle_wrap_enter(struct cpuidle_device *dev, | |
211 | struct cpuidle_driver *drv, int index, | |
212 | int (*enter)(struct cpuidle_device *dev, | |
213 | struct cpuidle_driver *drv, int index)) | |
214 | { | |
215 | ktime_t time_start, time_end; | |
216 | s64 diff; | |
217 | ||
218 | time_start = ktime_get(); | |
219 | ||
220 | index = enter(dev, drv, index); | |
221 | ||
222 | time_end = ktime_get(); | |
223 | ||
224 | local_irq_enable(); | |
225 | ||
226 | diff = ktime_to_us(ktime_sub(time_end, time_start)); | |
227 | if (diff > INT_MAX) | |
228 | diff = INT_MAX; | |
229 | ||
230 | dev->last_residency = (int) diff; | |
231 | ||
232 | return index; | |
233 | } | |
234 | ||
d8c216cf | 235 | #ifdef CONFIG_ARCH_HAS_CPU_RELAX |
46bcfad7 DD |
236 | static int poll_idle(struct cpuidle_device *dev, |
237 | struct cpuidle_driver *drv, int index) | |
d8c216cf RW |
238 | { |
239 | ktime_t t1, t2; | |
240 | s64 diff; | |
d8c216cf RW |
241 | |
242 | t1 = ktime_get(); | |
243 | local_irq_enable(); | |
244 | while (!need_resched()) | |
245 | cpu_relax(); | |
246 | ||
247 | t2 = ktime_get(); | |
248 | diff = ktime_to_us(ktime_sub(t2, t1)); | |
249 | if (diff > INT_MAX) | |
250 | diff = INT_MAX; | |
251 | ||
e978aa7d DD |
252 | dev->last_residency = (int) diff; |
253 | ||
254 | return index; | |
d8c216cf RW |
255 | } |
256 | ||
46bcfad7 | 257 | static void poll_idle_init(struct cpuidle_driver *drv) |
d8c216cf | 258 | { |
46bcfad7 | 259 | struct cpuidle_state *state = &drv->states[0]; |
d8c216cf | 260 | |
720f1c30 | 261 | snprintf(state->name, CPUIDLE_NAME_LEN, "POLL"); |
d8c216cf RW |
262 | snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE"); |
263 | state->exit_latency = 0; | |
264 | state->target_residency = 0; | |
265 | state->power_usage = -1; | |
d247632c | 266 | state->flags = 0; |
d8c216cf RW |
267 | state->enter = poll_idle; |
268 | } | |
269 | #else | |
46bcfad7 | 270 | static void poll_idle_init(struct cpuidle_driver *drv) {} |
d8c216cf RW |
271 | #endif /* CONFIG_ARCH_HAS_CPU_RELAX */ |
272 | ||
4f86d3a8 LB |
273 | /** |
274 | * cpuidle_enable_device - enables idle PM for a CPU | |
275 | * @dev: the CPU | |
276 | * | |
277 | * This function must be called between cpuidle_pause_and_lock and | |
278 | * cpuidle_resume_and_unlock when used externally. | |
279 | */ | |
280 | int cpuidle_enable_device(struct cpuidle_device *dev) | |
281 | { | |
282 | int ret, i; | |
e1689795 | 283 | struct cpuidle_driver *drv = cpuidle_get_driver(); |
4f86d3a8 LB |
284 | |
285 | if (dev->enabled) | |
286 | return 0; | |
e1689795 | 287 | if (!drv || !cpuidle_curr_governor) |
4f86d3a8 LB |
288 | return -EIO; |
289 | if (!dev->state_count) | |
fc850f39 | 290 | dev->state_count = drv->state_count; |
4f86d3a8 | 291 | |
dcb84f33 VP |
292 | if (dev->registered == 0) { |
293 | ret = __cpuidle_register_device(dev); | |
294 | if (ret) | |
295 | return ret; | |
296 | } | |
297 | ||
e1689795 RL |
298 | cpuidle_enter_ops = drv->en_core_tk_irqen ? |
299 | cpuidle_enter_tk : cpuidle_enter; | |
300 | ||
301 | poll_idle_init(drv); | |
d8c216cf | 302 | |
4f86d3a8 LB |
303 | if ((ret = cpuidle_add_state_sysfs(dev))) |
304 | return ret; | |
305 | ||
306 | if (cpuidle_curr_governor->enable && | |
e1689795 | 307 | (ret = cpuidle_curr_governor->enable(drv, dev))) |
4f86d3a8 LB |
308 | goto fail_sysfs; |
309 | ||
310 | for (i = 0; i < dev->state_count; i++) { | |
4202735e DD |
311 | dev->states_usage[i].usage = 0; |
312 | dev->states_usage[i].time = 0; | |
4f86d3a8 LB |
313 | } |
314 | dev->last_residency = 0; | |
4f86d3a8 LB |
315 | |
316 | smp_wmb(); | |
317 | ||
318 | dev->enabled = 1; | |
319 | ||
320 | enabled_devices++; | |
321 | return 0; | |
322 | ||
323 | fail_sysfs: | |
324 | cpuidle_remove_state_sysfs(dev); | |
325 | ||
326 | return ret; | |
327 | } | |
328 | ||
329 | EXPORT_SYMBOL_GPL(cpuidle_enable_device); | |
330 | ||
331 | /** | |
332 | * cpuidle_disable_device - disables idle PM for a CPU | |
333 | * @dev: the CPU | |
334 | * | |
335 | * This function must be called between cpuidle_pause_and_lock and | |
336 | * cpuidle_resume_and_unlock when used externally. | |
337 | */ | |
338 | void cpuidle_disable_device(struct cpuidle_device *dev) | |
339 | { | |
340 | if (!dev->enabled) | |
341 | return; | |
752138df | 342 | if (!cpuidle_get_driver() || !cpuidle_curr_governor) |
4f86d3a8 LB |
343 | return; |
344 | ||
345 | dev->enabled = 0; | |
346 | ||
347 | if (cpuidle_curr_governor->disable) | |
46bcfad7 | 348 | cpuidle_curr_governor->disable(cpuidle_get_driver(), dev); |
4f86d3a8 LB |
349 | |
350 | cpuidle_remove_state_sysfs(dev); | |
351 | enabled_devices--; | |
352 | } | |
353 | ||
354 | EXPORT_SYMBOL_GPL(cpuidle_disable_device); | |
355 | ||
356 | /** | |
dcb84f33 VP |
357 | * __cpuidle_register_device - internal register function called before register |
358 | * and enable routines | |
4f86d3a8 | 359 | * @dev: the cpu |
dcb84f33 VP |
360 | * |
361 | * cpuidle_lock mutex must be held before this is called | |
4f86d3a8 | 362 | */ |
dcb84f33 | 363 | static int __cpuidle_register_device(struct cpuidle_device *dev) |
4f86d3a8 LB |
364 | { |
365 | int ret; | |
8a25a2fd | 366 | struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu); |
752138df | 367 | struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver(); |
4f86d3a8 | 368 | |
8a25a2fd | 369 | if (!dev) |
4f86d3a8 | 370 | return -EINVAL; |
752138df | 371 | if (!try_module_get(cpuidle_driver->owner)) |
4f86d3a8 LB |
372 | return -EINVAL; |
373 | ||
374 | init_completion(&dev->kobj_unregister); | |
375 | ||
4f86d3a8 LB |
376 | per_cpu(cpuidle_devices, dev->cpu) = dev; |
377 | list_add(&dev->device_list, &cpuidle_detected_devices); | |
8a25a2fd | 378 | if ((ret = cpuidle_add_sysfs(cpu_dev))) { |
752138df | 379 | module_put(cpuidle_driver->owner); |
4f86d3a8 LB |
380 | return ret; |
381 | } | |
382 | ||
dcb84f33 VP |
383 | dev->registered = 1; |
384 | return 0; | |
385 | } | |
386 | ||
387 | /** | |
388 | * cpuidle_register_device - registers a CPU's idle PM feature | |
389 | * @dev: the cpu | |
390 | */ | |
391 | int cpuidle_register_device(struct cpuidle_device *dev) | |
392 | { | |
393 | int ret; | |
394 | ||
395 | mutex_lock(&cpuidle_lock); | |
396 | ||
397 | if ((ret = __cpuidle_register_device(dev))) { | |
398 | mutex_unlock(&cpuidle_lock); | |
399 | return ret; | |
400 | } | |
401 | ||
4f86d3a8 LB |
402 | cpuidle_enable_device(dev); |
403 | cpuidle_install_idle_handler(); | |
404 | ||
405 | mutex_unlock(&cpuidle_lock); | |
406 | ||
407 | return 0; | |
408 | ||
409 | } | |
410 | ||
411 | EXPORT_SYMBOL_GPL(cpuidle_register_device); | |
412 | ||
413 | /** | |
414 | * cpuidle_unregister_device - unregisters a CPU's idle PM feature | |
415 | * @dev: the cpu | |
416 | */ | |
417 | void cpuidle_unregister_device(struct cpuidle_device *dev) | |
418 | { | |
8a25a2fd | 419 | struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu); |
752138df | 420 | struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver(); |
4f86d3a8 | 421 | |
dcb84f33 VP |
422 | if (dev->registered == 0) |
423 | return; | |
424 | ||
4f86d3a8 LB |
425 | cpuidle_pause_and_lock(); |
426 | ||
427 | cpuidle_disable_device(dev); | |
428 | ||
8a25a2fd | 429 | cpuidle_remove_sysfs(cpu_dev); |
4f86d3a8 LB |
430 | list_del(&dev->device_list); |
431 | wait_for_completion(&dev->kobj_unregister); | |
432 | per_cpu(cpuidle_devices, dev->cpu) = NULL; | |
433 | ||
434 | cpuidle_resume_and_unlock(); | |
435 | ||
752138df | 436 | module_put(cpuidle_driver->owner); |
4f86d3a8 LB |
437 | } |
438 | ||
439 | EXPORT_SYMBOL_GPL(cpuidle_unregister_device); | |
440 | ||
441 | #ifdef CONFIG_SMP | |
442 | ||
443 | static void smp_callback(void *v) | |
444 | { | |
445 | /* we already woke the CPU up, nothing more to do */ | |
446 | } | |
447 | ||
448 | /* | |
449 | * This function gets called when a part of the kernel has a new latency | |
450 | * requirement. This means we need to get all processors out of their C-state, | |
451 | * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that | |
452 | * wakes them all right up. | |
453 | */ | |
454 | static int cpuidle_latency_notify(struct notifier_block *b, | |
455 | unsigned long l, void *v) | |
456 | { | |
8691e5a8 | 457 | smp_call_function(smp_callback, NULL, 1); |
4f86d3a8 LB |
458 | return NOTIFY_OK; |
459 | } | |
460 | ||
461 | static struct notifier_block cpuidle_latency_notifier = { | |
462 | .notifier_call = cpuidle_latency_notify, | |
463 | }; | |
464 | ||
d82b3518 MG |
465 | static inline void latency_notifier_init(struct notifier_block *n) |
466 | { | |
467 | pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n); | |
468 | } | |
4f86d3a8 LB |
469 | |
470 | #else /* CONFIG_SMP */ | |
471 | ||
472 | #define latency_notifier_init(x) do { } while (0) | |
473 | ||
474 | #endif /* CONFIG_SMP */ | |
475 | ||
476 | /** | |
477 | * cpuidle_init - core initializer | |
478 | */ | |
479 | static int __init cpuidle_init(void) | |
480 | { | |
481 | int ret; | |
482 | ||
62027aea LB |
483 | if (cpuidle_disabled()) |
484 | return -ENODEV; | |
485 | ||
8a25a2fd | 486 | ret = cpuidle_add_interface(cpu_subsys.dev_root); |
4f86d3a8 LB |
487 | if (ret) |
488 | return ret; | |
489 | ||
490 | latency_notifier_init(&cpuidle_latency_notifier); | |
491 | ||
492 | return 0; | |
493 | } | |
494 | ||
62027aea | 495 | module_param(off, int, 0444); |
4f86d3a8 | 496 | core_initcall(cpuidle_init); |