blob: 3210cf9eee10b3eb64ea282653b1857816d0a353 [file] [log] [blame]
lh9ed821d2023-04-07 01:36:19 -07001/*
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>
15#include <linux/pm_qos.h>
16#include <linux/cpu.h>
17#include <linux/cpuidle.h>
18#include <linux/ktime.h>
19#include <linux/hrtimer.h>
20#include <linux/module.h>
21#include <trace/events/power.h>
22
23#include "cpuidle.h"
24
25DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
26
27DEFINE_MUTEX(cpuidle_lock);
28LIST_HEAD(cpuidle_detected_devices);
29
30static int enabled_devices;
31static int off __read_mostly;
32static int initialized __read_mostly;
33
34int cpuidle_disabled(void)
35{
36 return off;
37}
38void disable_cpuidle(void)
39{
40 off = 1;
41}
42
43#if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT)
44static 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 */
51static void cpuidle_kick_cpus(void) {}
52#endif
53
54static int __cpuidle_register_device(struct cpuidle_device *dev);
55
56static 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
63static 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
69typedef int (*cpuidle_enter_t)(struct cpuidle_device *dev,
70 struct cpuidle_driver *drv, int index);
71
72static cpuidle_enter_t cpuidle_enter_ops;
73
74/**
75 * cpuidle_play_dead - cpu off-lining
76 *
77 * Returns in case of an error or no driver
78 */
79int 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
86 if (!drv)
87 return -ENODEV;
88
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
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 */
111int 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
133/**
134 * cpuidle_idle_call - the main idle loop
135 *
136 * NOTE: no locks or semaphores should be used here
137 * return non-zero on failure
138 */
139int cpuidle_idle_call(void)
140{
141 struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
142 struct cpuidle_driver *drv = cpuidle_get_driver();
143 int next_state, entered_state;
144
145 if (off)
146 return -ENODEV;
147
148 if (!initialized)
149 return -ENODEV;
150
151 /* check if the device is ready */
152 if (!dev || !dev->enabled)
153 return -EBUSY;
154
155#if 0
156 /* shows regressions, re-enable for 2.6.29 */
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();
162#endif
163
164 /* ask the governor for the next state */
165 next_state = cpuidle_curr_governor->select(drv, dev);
166 if (need_resched()) {
167 local_irq_enable();
168 return 0;
169 }
170
171 trace_power_start_rcuidle(POWER_CSTATE, next_state, dev->cpu);
172 trace_cpu_idle_rcuidle(next_state, dev->cpu);
173
174 if (cpuidle_state_is_coupled(dev, drv, next_state))
175 entered_state = cpuidle_enter_state_coupled(dev, drv,
176 next_state);
177 else
178 entered_state = cpuidle_enter_state(dev, drv, next_state);
179
180 trace_power_end_rcuidle(dev->cpu);
181 trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
182
183 /* give the governor an opportunity to reflect on the outcome */
184 if (cpuidle_curr_governor->reflect)
185 cpuidle_curr_governor->reflect(dev, entered_state);
186
187 return 0;
188}
189
190/**
191 * cpuidle_install_idle_handler - installs the cpuidle idle loop handler
192 */
193void cpuidle_install_idle_handler(void)
194{
195 if (enabled_devices) {
196 /* Make sure all changes finished before we switch to new idle */
197 smp_wmb();
198 initialized = 1;
199 }
200}
201
202/**
203 * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
204 */
205void cpuidle_uninstall_idle_handler(void)
206{
207 if (enabled_devices) {
208 initialized = 0;
209 cpuidle_kick_cpus();
210 }
211}
212
213/**
214 * cpuidle_pause_and_lock - temporarily disables CPUIDLE
215 */
216void cpuidle_pause_and_lock(void)
217{
218 mutex_lock(&cpuidle_lock);
219 cpuidle_uninstall_idle_handler();
220}
221
222EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);
223
224/**
225 * cpuidle_resume_and_unlock - resumes CPUIDLE operation
226 */
227void cpuidle_resume_and_unlock(void)
228{
229 cpuidle_install_idle_handler();
230 mutex_unlock(&cpuidle_lock);
231}
232
233EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);
234
235/**
236 * cpuidle_wrap_enter - performs timekeeping and irqen around enter function
237 * @dev: pointer to a valid cpuidle_device object
238 * @drv: pointer to a valid cpuidle_driver object
239 * @index: index of the target cpuidle state.
240 */
241int cpuidle_wrap_enter(struct cpuidle_device *dev,
242 struct cpuidle_driver *drv, int index,
243 int (*enter)(struct cpuidle_device *dev,
244 struct cpuidle_driver *drv, int index))
245{
246 ktime_t time_start, time_end;
247 s64 diff;
248
249 time_start = ktime_get();
250
251 index = enter(dev, drv, index);
252
253 time_end = ktime_get();
254
255 local_irq_enable();
256
257 diff = ktime_to_us(ktime_sub(time_end, time_start));
258 if (diff > INT_MAX)
259 diff = INT_MAX;
260
261 dev->last_residency = (int) diff;
262
263 return index;
264}
265
266#ifdef CONFIG_ARCH_HAS_CPU_RELAX
267static int poll_idle(struct cpuidle_device *dev,
268 struct cpuidle_driver *drv, int index)
269{
270 ktime_t t1, t2;
271 s64 diff;
272
273 t1 = ktime_get();
274 local_irq_enable();
275 while (!need_resched())
276 cpu_relax();
277
278 t2 = ktime_get();
279 diff = ktime_to_us(ktime_sub(t2, t1));
280 if (diff > INT_MAX)
281 diff = INT_MAX;
282
283 dev->last_residency = (int) diff;
284
285 return index;
286}
287
288static void poll_idle_init(struct cpuidle_driver *drv)
289{
290 struct cpuidle_state *state = &drv->states[0];
291
292 snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
293 snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
294 state->exit_latency = 0;
295 state->target_residency = 0;
296 state->power_usage = -1;
297 state->flags = 0;
298 state->enter = poll_idle;
299 state->disable = 0;
300}
301#else
302static void poll_idle_init(struct cpuidle_driver *drv) {}
303#endif /* CONFIG_ARCH_HAS_CPU_RELAX */
304
305/**
306 * cpuidle_enable_device - enables idle PM for a CPU
307 * @dev: the CPU
308 *
309 * This function must be called between cpuidle_pause_and_lock and
310 * cpuidle_resume_and_unlock when used externally.
311 */
312int cpuidle_enable_device(struct cpuidle_device *dev)
313{
314 int ret, i;
315 struct cpuidle_driver *drv = cpuidle_get_driver();
316
317 if (dev->enabled)
318 return 0;
319 if (!drv || !cpuidle_curr_governor)
320 return -EIO;
321 if (!dev->state_count)
322 dev->state_count = drv->state_count;
323
324 if (dev->registered == 0) {
325 ret = __cpuidle_register_device(dev);
326 if (ret)
327 return ret;
328 }
329
330 cpuidle_enter_ops = drv->en_core_tk_irqen ?
331 cpuidle_enter_tk : cpuidle_enter;
332
333 poll_idle_init(drv);
334
335 if ((ret = cpuidle_add_state_sysfs(dev)))
336 return ret;
337
338 if (cpuidle_curr_governor->enable &&
339 (ret = cpuidle_curr_governor->enable(drv, dev)))
340 goto fail_sysfs;
341
342 for (i = 0; i < dev->state_count; i++) {
343 dev->states_usage[i].usage = 0;
344 dev->states_usage[i].time = 0;
345 }
346 dev->last_residency = 0;
347
348 smp_wmb();
349
350 dev->enabled = 1;
351
352 enabled_devices++;
353 return 0;
354
355fail_sysfs:
356 cpuidle_remove_state_sysfs(dev);
357
358 return ret;
359}
360
361EXPORT_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 */
370void cpuidle_disable_device(struct cpuidle_device *dev)
371{
372 if (!dev->enabled)
373 return;
374 if (!cpuidle_get_driver() || !cpuidle_curr_governor)
375 return;
376
377 dev->enabled = 0;
378
379 if (cpuidle_curr_governor->disable)
380 cpuidle_curr_governor->disable(cpuidle_get_driver(), dev);
381
382 cpuidle_remove_state_sysfs(dev);
383 enabled_devices--;
384}
385
386EXPORT_SYMBOL_GPL(cpuidle_disable_device);
387
388/**
389 * __cpuidle_register_device - internal register function called before register
390 * and enable routines
391 * @dev: the cpu
392 *
393 * cpuidle_lock mutex must be held before this is called
394 */
395static int __cpuidle_register_device(struct cpuidle_device *dev)
396{
397 int ret;
398 struct device *cpu_dev=NULL ; //= get_cpu_device((unsigned long)dev->cpu);
399 struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
400
401 if (!dev)
402 return -EINVAL;
403
404 cpu_dev = get_cpu_device((unsigned long)dev->cpu);
405
406 if(cpu_dev == NULL)
407 return -EINVAL;
408 if (!try_module_get(cpuidle_driver->owner))
409 return -EINVAL;
410
411 init_completion(&dev->kobj_unregister);
412
413 per_cpu(cpuidle_devices, dev->cpu) = dev;
414 list_add(&dev->device_list, &cpuidle_detected_devices);
415 ret = cpuidle_add_sysfs(cpu_dev);
416 if (ret)
417 goto err_sysfs;
418
419 ret = cpuidle_coupled_register_device(dev);
420 if (ret)
421 goto err_coupled;
422
423 dev->registered = 1;
424 return 0;
425
426err_coupled:
427 cpuidle_remove_sysfs(cpu_dev);
428 wait_for_completion(&dev->kobj_unregister);
429err_sysfs:
430 list_del(&dev->device_list);
431 per_cpu(cpuidle_devices, dev->cpu) = NULL;
432 module_put(cpuidle_driver->owner);
433 return ret;
434}
435
436/**
437 * cpuidle_register_device - registers a CPU's idle PM feature
438 * @dev: the cpu
439 */
440int cpuidle_register_device(struct cpuidle_device *dev)
441{
442 int ret;
443
444 mutex_lock(&cpuidle_lock);
445
446 if ((ret = __cpuidle_register_device(dev))) {
447 mutex_unlock(&cpuidle_lock);
448 return ret;
449 }
450
451 cpuidle_enable_device(dev);
452 cpuidle_install_idle_handler();
453
454 mutex_unlock(&cpuidle_lock);
455
456 return 0;
457
458}
459
460EXPORT_SYMBOL_GPL(cpuidle_register_device);
461
462/**
463 * cpuidle_unregister_device - unregisters a CPU's idle PM feature
464 * @dev: the cpu
465 */
466void cpuidle_unregister_device(struct cpuidle_device *dev)
467{
468 struct device *cpu_dev=NULL ; //= get_cpu_device((unsigned long)dev->cpu);
469 struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
470
471 if (dev == NULL)
472 return;
473 if (dev->registered == 0)
474 return;
475
476 cpu_dev = get_cpu_device((unsigned long)dev->cpu);
477
478 if(cpu_dev == NULL)
479 return;
480
481 cpuidle_pause_and_lock();
482
483 cpuidle_disable_device(dev);
484
485 cpuidle_remove_sysfs(cpu_dev);
486 list_del(&dev->device_list);
487 wait_for_completion(&dev->kobj_unregister);
488 per_cpu(cpuidle_devices, dev->cpu) = NULL;
489
490 cpuidle_coupled_unregister_device(dev);
491
492 cpuidle_resume_and_unlock();
493
494 module_put(cpuidle_driver->owner);
495}
496
497EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
498
499#ifdef CONFIG_SMP
500
501static void smp_callback(void *v)
502{
503 /* we already woke the CPU up, nothing more to do */
504}
505
506/*
507 * This function gets called when a part of the kernel has a new latency
508 * requirement. This means we need to get all processors out of their C-state,
509 * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
510 * wakes them all right up.
511 */
512static int cpuidle_latency_notify(struct notifier_block *b,
513 unsigned long l, void *v)
514{
515 smp_call_function(smp_callback, NULL, 1);
516 return NOTIFY_OK;
517}
518
519static struct notifier_block cpuidle_latency_notifier = {
520 .notifier_call = cpuidle_latency_notify,
521};
522
523static inline void latency_notifier_init(struct notifier_block *n)
524{
525 pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
526}
527
528#else /* CONFIG_SMP */
529
530#define latency_notifier_init(x) do { } while (0)
531
532#endif /* CONFIG_SMP */
533
534/**
535 * cpuidle_init - core initializer
536 */
537static int __init cpuidle_init(void)
538{
539 int ret;
540
541 if (cpuidle_disabled())
542 return -ENODEV;
543
544 ret = cpuidle_add_interface(cpu_subsys.dev_root);
545 if (ret)
546 return ret;
547
548 latency_notifier_init(&cpuidle_latency_notifier);
549
550 return 0;
551}
552
553module_param(off, int, 0444);
554core_initcall(cpuidle_init);