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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 | ||
4f86d3a8 LB |
74 | /** |
75 | * cpuidle_idle_call - the main idle loop | |
76 | * | |
77 | * NOTE: no locks or semaphores should be used here | |
a0bfa137 | 78 | * return non-zero on failure |
4f86d3a8 | 79 | */ |
a0bfa137 | 80 | int cpuidle_idle_call(void) |
4f86d3a8 | 81 | { |
4a6f4fe8 | 82 | struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); |
46bcfad7 | 83 | struct cpuidle_driver *drv = cpuidle_get_driver(); |
e978aa7d | 84 | int next_state, entered_state; |
4f86d3a8 | 85 | |
a0bfa137 LB |
86 | if (off) |
87 | return -ENODEV; | |
88 | ||
89 | if (!initialized) | |
90 | return -ENODEV; | |
91 | ||
4f86d3a8 | 92 | /* check if the device is ready */ |
a0bfa137 LB |
93 | if (!dev || !dev->enabled) |
94 | return -EBUSY; | |
4f86d3a8 | 95 | |
9a655837 AV |
96 | #if 0 |
97 | /* shows regressions, re-enable for 2.6.29 */ | |
2e94d1f7 AV |
98 | /* |
99 | * run any timers that can be run now, at this point | |
100 | * before calculating the idle duration etc. | |
101 | */ | |
102 | hrtimer_peek_ahead_timers(); | |
9a655837 | 103 | #endif |
71abbbf8 | 104 | |
4f86d3a8 | 105 | /* ask the governor for the next state */ |
46bcfad7 | 106 | next_state = cpuidle_curr_governor->select(drv, dev); |
246eb7f0 KH |
107 | if (need_resched()) { |
108 | local_irq_enable(); | |
a0bfa137 | 109 | return 0; |
246eb7f0 KH |
110 | } |
111 | ||
f77cfe4e TR |
112 | trace_power_start(POWER_CSTATE, next_state, dev->cpu); |
113 | trace_cpu_idle(next_state, dev->cpu); | |
114 | ||
e1689795 | 115 | entered_state = cpuidle_enter_ops(dev, drv, next_state); |
f77cfe4e TR |
116 | |
117 | trace_power_end(dev->cpu); | |
118 | trace_cpu_idle(PWR_EVENT_EXIT, dev->cpu); | |
119 | ||
e978aa7d DD |
120 | if (entered_state >= 0) { |
121 | /* Update cpuidle counters */ | |
122 | /* This can be moved to within driver enter routine | |
123 | * but that results in multiple copies of same code. | |
124 | */ | |
4202735e | 125 | dev->states_usage[entered_state].time += |
e978aa7d | 126 | (unsigned long long)dev->last_residency; |
4202735e | 127 | dev->states_usage[entered_state].usage++; |
e1689795 RL |
128 | } else { |
129 | dev->last_residency = 0; | |
e978aa7d | 130 | } |
4f86d3a8 LB |
131 | |
132 | /* give the governor an opportunity to reflect on the outcome */ | |
133 | if (cpuidle_curr_governor->reflect) | |
e978aa7d | 134 | cpuidle_curr_governor->reflect(dev, entered_state); |
a0bfa137 LB |
135 | |
136 | return 0; | |
4f86d3a8 LB |
137 | } |
138 | ||
139 | /** | |
140 | * cpuidle_install_idle_handler - installs the cpuidle idle loop handler | |
141 | */ | |
142 | void cpuidle_install_idle_handler(void) | |
143 | { | |
a0bfa137 | 144 | if (enabled_devices) { |
4f86d3a8 LB |
145 | /* Make sure all changes finished before we switch to new idle */ |
146 | smp_wmb(); | |
a0bfa137 | 147 | initialized = 1; |
4f86d3a8 LB |
148 | } |
149 | } | |
150 | ||
151 | /** | |
152 | * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler | |
153 | */ | |
154 | void cpuidle_uninstall_idle_handler(void) | |
155 | { | |
a0bfa137 LB |
156 | if (enabled_devices) { |
157 | initialized = 0; | |
a6869cc4 | 158 | cpuidle_kick_cpus(); |
4f86d3a8 LB |
159 | } |
160 | } | |
161 | ||
162 | /** | |
163 | * cpuidle_pause_and_lock - temporarily disables CPUIDLE | |
164 | */ | |
165 | void cpuidle_pause_and_lock(void) | |
166 | { | |
167 | mutex_lock(&cpuidle_lock); | |
168 | cpuidle_uninstall_idle_handler(); | |
169 | } | |
170 | ||
171 | EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock); | |
172 | ||
173 | /** | |
174 | * cpuidle_resume_and_unlock - resumes CPUIDLE operation | |
175 | */ | |
176 | void cpuidle_resume_and_unlock(void) | |
177 | { | |
178 | cpuidle_install_idle_handler(); | |
179 | mutex_unlock(&cpuidle_lock); | |
180 | } | |
181 | ||
182 | EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock); | |
183 | ||
e1689795 RL |
184 | /** |
185 | * cpuidle_wrap_enter - performs timekeeping and irqen around enter function | |
186 | * @dev: pointer to a valid cpuidle_device object | |
187 | * @drv: pointer to a valid cpuidle_driver object | |
188 | * @index: index of the target cpuidle state. | |
189 | */ | |
190 | int cpuidle_wrap_enter(struct cpuidle_device *dev, | |
191 | struct cpuidle_driver *drv, int index, | |
192 | int (*enter)(struct cpuidle_device *dev, | |
193 | struct cpuidle_driver *drv, int index)) | |
194 | { | |
195 | ktime_t time_start, time_end; | |
196 | s64 diff; | |
197 | ||
198 | time_start = ktime_get(); | |
199 | ||
200 | index = enter(dev, drv, index); | |
201 | ||
202 | time_end = ktime_get(); | |
203 | ||
204 | local_irq_enable(); | |
205 | ||
206 | diff = ktime_to_us(ktime_sub(time_end, time_start)); | |
207 | if (diff > INT_MAX) | |
208 | diff = INT_MAX; | |
209 | ||
210 | dev->last_residency = (int) diff; | |
211 | ||
212 | return index; | |
213 | } | |
214 | ||
d8c216cf | 215 | #ifdef CONFIG_ARCH_HAS_CPU_RELAX |
46bcfad7 DD |
216 | static int poll_idle(struct cpuidle_device *dev, |
217 | struct cpuidle_driver *drv, int index) | |
d8c216cf RW |
218 | { |
219 | ktime_t t1, t2; | |
220 | s64 diff; | |
d8c216cf RW |
221 | |
222 | t1 = ktime_get(); | |
223 | local_irq_enable(); | |
224 | while (!need_resched()) | |
225 | cpu_relax(); | |
226 | ||
227 | t2 = ktime_get(); | |
228 | diff = ktime_to_us(ktime_sub(t2, t1)); | |
229 | if (diff > INT_MAX) | |
230 | diff = INT_MAX; | |
231 | ||
e978aa7d DD |
232 | dev->last_residency = (int) diff; |
233 | ||
234 | return index; | |
d8c216cf RW |
235 | } |
236 | ||
46bcfad7 | 237 | static void poll_idle_init(struct cpuidle_driver *drv) |
d8c216cf | 238 | { |
46bcfad7 | 239 | struct cpuidle_state *state = &drv->states[0]; |
d8c216cf | 240 | |
720f1c30 | 241 | snprintf(state->name, CPUIDLE_NAME_LEN, "POLL"); |
d8c216cf RW |
242 | snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE"); |
243 | state->exit_latency = 0; | |
244 | state->target_residency = 0; | |
245 | state->power_usage = -1; | |
d247632c | 246 | state->flags = 0; |
d8c216cf | 247 | state->enter = poll_idle; |
3a53396b | 248 | state->disable = 0; |
d8c216cf RW |
249 | } |
250 | #else | |
46bcfad7 | 251 | static void poll_idle_init(struct cpuidle_driver *drv) {} |
d8c216cf RW |
252 | #endif /* CONFIG_ARCH_HAS_CPU_RELAX */ |
253 | ||
4f86d3a8 LB |
254 | /** |
255 | * cpuidle_enable_device - enables idle PM for a CPU | |
256 | * @dev: the CPU | |
257 | * | |
258 | * This function must be called between cpuidle_pause_and_lock and | |
259 | * cpuidle_resume_and_unlock when used externally. | |
260 | */ | |
261 | int cpuidle_enable_device(struct cpuidle_device *dev) | |
262 | { | |
263 | int ret, i; | |
e1689795 | 264 | struct cpuidle_driver *drv = cpuidle_get_driver(); |
4f86d3a8 LB |
265 | |
266 | if (dev->enabled) | |
267 | return 0; | |
e1689795 | 268 | if (!drv || !cpuidle_curr_governor) |
4f86d3a8 LB |
269 | return -EIO; |
270 | if (!dev->state_count) | |
271 | return -EINVAL; | |
272 | ||
dcb84f33 VP |
273 | if (dev->registered == 0) { |
274 | ret = __cpuidle_register_device(dev); | |
275 | if (ret) | |
276 | return ret; | |
277 | } | |
278 | ||
e1689795 RL |
279 | cpuidle_enter_ops = drv->en_core_tk_irqen ? |
280 | cpuidle_enter_tk : cpuidle_enter; | |
281 | ||
282 | poll_idle_init(drv); | |
d8c216cf | 283 | |
4f86d3a8 LB |
284 | if ((ret = cpuidle_add_state_sysfs(dev))) |
285 | return ret; | |
286 | ||
287 | if (cpuidle_curr_governor->enable && | |
e1689795 | 288 | (ret = cpuidle_curr_governor->enable(drv, dev))) |
4f86d3a8 LB |
289 | goto fail_sysfs; |
290 | ||
291 | for (i = 0; i < dev->state_count; i++) { | |
4202735e DD |
292 | dev->states_usage[i].usage = 0; |
293 | dev->states_usage[i].time = 0; | |
4f86d3a8 LB |
294 | } |
295 | dev->last_residency = 0; | |
4f86d3a8 LB |
296 | |
297 | smp_wmb(); | |
298 | ||
299 | dev->enabled = 1; | |
300 | ||
301 | enabled_devices++; | |
302 | return 0; | |
303 | ||
304 | fail_sysfs: | |
305 | cpuidle_remove_state_sysfs(dev); | |
306 | ||
307 | return ret; | |
308 | } | |
309 | ||
310 | EXPORT_SYMBOL_GPL(cpuidle_enable_device); | |
311 | ||
312 | /** | |
313 | * cpuidle_disable_device - disables idle PM for a CPU | |
314 | * @dev: the CPU | |
315 | * | |
316 | * This function must be called between cpuidle_pause_and_lock and | |
317 | * cpuidle_resume_and_unlock when used externally. | |
318 | */ | |
319 | void cpuidle_disable_device(struct cpuidle_device *dev) | |
320 | { | |
321 | if (!dev->enabled) | |
322 | return; | |
752138df | 323 | if (!cpuidle_get_driver() || !cpuidle_curr_governor) |
4f86d3a8 LB |
324 | return; |
325 | ||
326 | dev->enabled = 0; | |
327 | ||
328 | if (cpuidle_curr_governor->disable) | |
46bcfad7 | 329 | cpuidle_curr_governor->disable(cpuidle_get_driver(), dev); |
4f86d3a8 LB |
330 | |
331 | cpuidle_remove_state_sysfs(dev); | |
332 | enabled_devices--; | |
333 | } | |
334 | ||
335 | EXPORT_SYMBOL_GPL(cpuidle_disable_device); | |
336 | ||
337 | /** | |
dcb84f33 VP |
338 | * __cpuidle_register_device - internal register function called before register |
339 | * and enable routines | |
4f86d3a8 | 340 | * @dev: the cpu |
dcb84f33 VP |
341 | * |
342 | * cpuidle_lock mutex must be held before this is called | |
4f86d3a8 | 343 | */ |
dcb84f33 | 344 | static int __cpuidle_register_device(struct cpuidle_device *dev) |
4f86d3a8 LB |
345 | { |
346 | int ret; | |
8a25a2fd | 347 | struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu); |
752138df | 348 | struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver(); |
4f86d3a8 | 349 | |
8a25a2fd | 350 | if (!dev) |
4f86d3a8 | 351 | return -EINVAL; |
752138df | 352 | if (!try_module_get(cpuidle_driver->owner)) |
4f86d3a8 LB |
353 | return -EINVAL; |
354 | ||
355 | init_completion(&dev->kobj_unregister); | |
356 | ||
4f86d3a8 LB |
357 | per_cpu(cpuidle_devices, dev->cpu) = dev; |
358 | list_add(&dev->device_list, &cpuidle_detected_devices); | |
8a25a2fd | 359 | if ((ret = cpuidle_add_sysfs(cpu_dev))) { |
752138df | 360 | module_put(cpuidle_driver->owner); |
4f86d3a8 LB |
361 | return ret; |
362 | } | |
363 | ||
dcb84f33 VP |
364 | dev->registered = 1; |
365 | return 0; | |
366 | } | |
367 | ||
368 | /** | |
369 | * cpuidle_register_device - registers a CPU's idle PM feature | |
370 | * @dev: the cpu | |
371 | */ | |
372 | int cpuidle_register_device(struct cpuidle_device *dev) | |
373 | { | |
374 | int ret; | |
375 | ||
376 | mutex_lock(&cpuidle_lock); | |
377 | ||
378 | if ((ret = __cpuidle_register_device(dev))) { | |
379 | mutex_unlock(&cpuidle_lock); | |
380 | return ret; | |
381 | } | |
382 | ||
4f86d3a8 LB |
383 | cpuidle_enable_device(dev); |
384 | cpuidle_install_idle_handler(); | |
385 | ||
386 | mutex_unlock(&cpuidle_lock); | |
387 | ||
388 | return 0; | |
389 | ||
390 | } | |
391 | ||
392 | EXPORT_SYMBOL_GPL(cpuidle_register_device); | |
393 | ||
394 | /** | |
395 | * cpuidle_unregister_device - unregisters a CPU's idle PM feature | |
396 | * @dev: the cpu | |
397 | */ | |
398 | void cpuidle_unregister_device(struct cpuidle_device *dev) | |
399 | { | |
8a25a2fd | 400 | struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu); |
752138df | 401 | struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver(); |
4f86d3a8 | 402 | |
dcb84f33 VP |
403 | if (dev->registered == 0) |
404 | return; | |
405 | ||
4f86d3a8 LB |
406 | cpuidle_pause_and_lock(); |
407 | ||
408 | cpuidle_disable_device(dev); | |
409 | ||
8a25a2fd | 410 | cpuidle_remove_sysfs(cpu_dev); |
4f86d3a8 LB |
411 | list_del(&dev->device_list); |
412 | wait_for_completion(&dev->kobj_unregister); | |
413 | per_cpu(cpuidle_devices, dev->cpu) = NULL; | |
414 | ||
415 | cpuidle_resume_and_unlock(); | |
416 | ||
752138df | 417 | module_put(cpuidle_driver->owner); |
4f86d3a8 LB |
418 | } |
419 | ||
420 | EXPORT_SYMBOL_GPL(cpuidle_unregister_device); | |
421 | ||
422 | #ifdef CONFIG_SMP | |
423 | ||
424 | static void smp_callback(void *v) | |
425 | { | |
426 | /* we already woke the CPU up, nothing more to do */ | |
427 | } | |
428 | ||
429 | /* | |
430 | * This function gets called when a part of the kernel has a new latency | |
431 | * requirement. This means we need to get all processors out of their C-state, | |
432 | * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that | |
433 | * wakes them all right up. | |
434 | */ | |
435 | static int cpuidle_latency_notify(struct notifier_block *b, | |
436 | unsigned long l, void *v) | |
437 | { | |
8691e5a8 | 438 | smp_call_function(smp_callback, NULL, 1); |
4f86d3a8 LB |
439 | return NOTIFY_OK; |
440 | } | |
441 | ||
442 | static struct notifier_block cpuidle_latency_notifier = { | |
443 | .notifier_call = cpuidle_latency_notify, | |
444 | }; | |
445 | ||
d82b3518 MG |
446 | static inline void latency_notifier_init(struct notifier_block *n) |
447 | { | |
448 | pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n); | |
449 | } | |
4f86d3a8 LB |
450 | |
451 | #else /* CONFIG_SMP */ | |
452 | ||
453 | #define latency_notifier_init(x) do { } while (0) | |
454 | ||
455 | #endif /* CONFIG_SMP */ | |
456 | ||
457 | /** | |
458 | * cpuidle_init - core initializer | |
459 | */ | |
460 | static int __init cpuidle_init(void) | |
461 | { | |
462 | int ret; | |
463 | ||
62027aea LB |
464 | if (cpuidle_disabled()) |
465 | return -ENODEV; | |
466 | ||
8a25a2fd | 467 | ret = cpuidle_add_interface(cpu_subsys.dev_root); |
4f86d3a8 LB |
468 | if (ret) |
469 | return ret; | |
470 | ||
471 | latency_notifier_init(&cpuidle_latency_notifier); | |
472 | ||
473 | return 0; | |
474 | } | |
475 | ||
62027aea | 476 | module_param(off, int, 0444); |
4f86d3a8 | 477 | core_initcall(cpuidle_init); |