1/*
2 * sysfs.c - sysfs support
3 *
4 * (C) 2006-2007 Shaohua Li <shaohua.li@intel.com>
5 *
6 * This code is licenced under the GPL.
7 */
8
9#include <linux/kernel.h>
10#include <linux/cpuidle.h>
11#include <linux/sysfs.h>
12#include <linux/slab.h>
13#include <linux/cpu.h>
14#include <linux/completion.h>
15#include <linux/capability.h>
16#include <linux/device.h>
17#include <linux/kobject.h>
18
19#include "cpuidle.h"
20
21static ssize_t show_available_governors(struct device *dev,
22 struct device_attribute *attr,
23 char *buf)
24{
25 ssize_t i = 0;
26 struct cpuidle_governor *tmp;
27
28 mutex_lock(&cpuidle_lock);
29 list_for_each_entry(tmp, &cpuidle_governors, governor_list) {
30 if (i >= (ssize_t)(PAGE_SIZE - (CPUIDLE_NAME_LEN + 2)))
31 goto out;
32
33 i += sysfs_emit_at(buf, at: i, fmt: "%.*s ", CPUIDLE_NAME_LEN, tmp->name);
34 }
35
36out:
37 i += sysfs_emit_at(buf, at: i, fmt: "\n");
38 mutex_unlock(lock: &cpuidle_lock);
39 return i;
40}
41
42static ssize_t show_current_driver(struct device *dev,
43 struct device_attribute *attr,
44 char *buf)
45{
46 ssize_t ret;
47 struct cpuidle_driver *drv;
48
49 spin_lock(lock: &cpuidle_driver_lock);
50 drv = cpuidle_get_driver();
51 if (drv)
52 ret = sysfs_emit(buf, fmt: "%s\n", drv->name);
53 else
54 ret = sysfs_emit(buf, fmt: "none\n");
55 spin_unlock(lock: &cpuidle_driver_lock);
56
57 return ret;
58}
59
60static ssize_t show_current_governor(struct device *dev,
61 struct device_attribute *attr,
62 char *buf)
63{
64 ssize_t ret;
65
66 mutex_lock(&cpuidle_lock);
67 if (cpuidle_curr_governor)
68 ret = sysfs_emit(buf, fmt: "%s\n", cpuidle_curr_governor->name);
69 else
70 ret = sysfs_emit(buf, fmt: "none\n");
71 mutex_unlock(lock: &cpuidle_lock);
72
73 return ret;
74}
75
76static ssize_t store_current_governor(struct device *dev,
77 struct device_attribute *attr,
78 const char *buf, size_t count)
79{
80 char gov_name[CPUIDLE_NAME_LEN + 1];
81 int ret;
82 struct cpuidle_governor *gov;
83
84 ret = sscanf(buf, "%" __stringify(CPUIDLE_NAME_LEN) "s", gov_name);
85 if (ret != 1)
86 return -EINVAL;
87
88 mutex_lock(&cpuidle_lock);
89 ret = -EINVAL;
90 list_for_each_entry(gov, &cpuidle_governors, governor_list) {
91 if (!strncmp(gov->name, gov_name, CPUIDLE_NAME_LEN)) {
92 ret = cpuidle_switch_governor(gov);
93 break;
94 }
95 }
96 mutex_unlock(lock: &cpuidle_lock);
97
98 return ret ? ret : count;
99}
100
101static DEVICE_ATTR(available_governors, 0444, show_available_governors, NULL);
102static DEVICE_ATTR(current_driver, 0444, show_current_driver, NULL);
103static DEVICE_ATTR(current_governor, 0644, show_current_governor,
104 store_current_governor);
105static DEVICE_ATTR(current_governor_ro, 0444, show_current_governor, NULL);
106
107static struct attribute *cpuidle_attrs[] = {
108 &dev_attr_available_governors.attr,
109 &dev_attr_current_driver.attr,
110 &dev_attr_current_governor.attr,
111 &dev_attr_current_governor_ro.attr,
112 NULL
113};
114
115static struct attribute_group cpuidle_attr_group = {
116 .attrs = cpuidle_attrs,
117 .name = "cpuidle",
118};
119
120/**
121 * cpuidle_add_interface - add CPU global sysfs attributes
122 */
123int cpuidle_add_interface(void)
124{
125 struct device *dev_root = bus_get_dev_root(bus: &cpu_subsys);
126 int retval;
127
128 if (!dev_root)
129 return -EINVAL;
130
131 retval = sysfs_create_group(kobj: &dev_root->kobj, grp: &cpuidle_attr_group);
132 put_device(dev: dev_root);
133 return retval;
134}
135
136/**
137 * cpuidle_remove_interface - remove CPU global sysfs attributes
138 * @dev: the target device
139 */
140void cpuidle_remove_interface(struct device *dev)
141{
142 sysfs_remove_group(kobj: &dev->kobj, grp: &cpuidle_attr_group);
143}
144
145struct cpuidle_attr {
146 struct attribute attr;
147 ssize_t (*show)(struct cpuidle_device *, char *);
148 ssize_t (*store)(struct cpuidle_device *, const char *, size_t count);
149};
150
151#define attr_to_cpuidleattr(a) container_of(a, struct cpuidle_attr, attr)
152
153struct cpuidle_device_kobj {
154 struct cpuidle_device *dev;
155 struct completion kobj_unregister;
156 struct kobject kobj;
157};
158
159static inline struct cpuidle_device *to_cpuidle_device(struct kobject *kobj)
160{
161 struct cpuidle_device_kobj *kdev =
162 container_of(kobj, struct cpuidle_device_kobj, kobj);
163
164 return kdev->dev;
165}
166
167static ssize_t cpuidle_show(struct kobject *kobj, struct attribute *attr,
168 char *buf)
169{
170 int ret = -EIO;
171 struct cpuidle_device *dev = to_cpuidle_device(kobj);
172 struct cpuidle_attr *cattr = attr_to_cpuidleattr(attr);
173
174 if (cattr->show) {
175 mutex_lock(&cpuidle_lock);
176 ret = cattr->show(dev, buf);
177 mutex_unlock(lock: &cpuidle_lock);
178 }
179 return ret;
180}
181
182static ssize_t cpuidle_store(struct kobject *kobj, struct attribute *attr,
183 const char *buf, size_t count)
184{
185 int ret = -EIO;
186 struct cpuidle_device *dev = to_cpuidle_device(kobj);
187 struct cpuidle_attr *cattr = attr_to_cpuidleattr(attr);
188
189 if (cattr->store) {
190 mutex_lock(&cpuidle_lock);
191 ret = cattr->store(dev, buf, count);
192 mutex_unlock(lock: &cpuidle_lock);
193 }
194 return ret;
195}
196
197static const struct sysfs_ops cpuidle_sysfs_ops = {
198 .show = cpuidle_show,
199 .store = cpuidle_store,
200};
201
202static void cpuidle_sysfs_release(struct kobject *kobj)
203{
204 struct cpuidle_device_kobj *kdev =
205 container_of(kobj, struct cpuidle_device_kobj, kobj);
206
207 complete(&kdev->kobj_unregister);
208}
209
210static const struct kobj_type ktype_cpuidle = {
211 .sysfs_ops = &cpuidle_sysfs_ops,
212 .release = cpuidle_sysfs_release,
213};
214
215struct cpuidle_state_attr {
216 struct attribute attr;
217 ssize_t (*show)(struct cpuidle_state *, \
218 struct cpuidle_state_usage *, char *);
219 ssize_t (*store)(struct cpuidle_state *, \
220 struct cpuidle_state_usage *, const char *, size_t);
221};
222
223#define define_one_state_ro(_name, show) \
224static struct cpuidle_state_attr attr_##_name = __ATTR(_name, 0444, show, NULL)
225
226#define define_one_state_rw(_name, show, store) \
227static struct cpuidle_state_attr attr_##_name = __ATTR(_name, 0644, show, store)
228
229#define define_show_state_function(_name) \
230static ssize_t show_state_##_name(struct cpuidle_state *state, \
231 struct cpuidle_state_usage *state_usage, char *buf) \
232{ \
233 return sysfs_emit(buf, "%u\n", state->_name);\
234}
235
236#define define_show_state_ull_function(_name) \
237static ssize_t show_state_##_name(struct cpuidle_state *state, \
238 struct cpuidle_state_usage *state_usage, \
239 char *buf) \
240{ \
241 return sysfs_emit(buf, "%llu\n", state_usage->_name);\
242}
243
244#define define_show_state_str_function(_name) \
245static ssize_t show_state_##_name(struct cpuidle_state *state, \
246 struct cpuidle_state_usage *state_usage, \
247 char *buf) \
248{ \
249 if (state->_name[0] == '\0')\
250 return sysfs_emit(buf, "<null>\n");\
251 return sysfs_emit(buf, "%s\n", state->_name);\
252}
253
254#define define_show_state_time_function(_name) \
255static ssize_t show_state_##_name(struct cpuidle_state *state, \
256 struct cpuidle_state_usage *state_usage, \
257 char *buf) \
258{ \
259 return sysfs_emit(buf, "%llu\n", ktime_to_us(state->_name##_ns)); \
260}
261
262define_show_state_time_function(exit_latency)
263define_show_state_time_function(target_residency)
264define_show_state_function(power_usage)
265define_show_state_ull_function(usage)
266define_show_state_ull_function(rejected)
267define_show_state_str_function(name)
268define_show_state_str_function(desc)
269define_show_state_ull_function(above)
270define_show_state_ull_function(below)
271
272static ssize_t show_state_time(struct cpuidle_state *state,
273 struct cpuidle_state_usage *state_usage,
274 char *buf)
275{
276 return sysfs_emit(buf, fmt: "%llu\n", ktime_to_us(kt: state_usage->time_ns));
277}
278
279static ssize_t show_state_disable(struct cpuidle_state *state,
280 struct cpuidle_state_usage *state_usage,
281 char *buf)
282{
283 return sysfs_emit(buf, fmt: "%llu\n",
284 state_usage->disable & CPUIDLE_STATE_DISABLED_BY_USER);
285}
286
287static ssize_t store_state_disable(struct cpuidle_state *state,
288 struct cpuidle_state_usage *state_usage,
289 const char *buf, size_t size)
290{
291 unsigned int value;
292 int err;
293
294 if (!capable(CAP_SYS_ADMIN))
295 return -EPERM;
296
297 err = kstrtouint(s: buf, base: 0, res: &value);
298 if (err)
299 return err;
300
301 if (value)
302 state_usage->disable |= CPUIDLE_STATE_DISABLED_BY_USER;
303 else
304 state_usage->disable &= ~CPUIDLE_STATE_DISABLED_BY_USER;
305
306 return size;
307}
308
309static ssize_t show_state_default_status(struct cpuidle_state *state,
310 struct cpuidle_state_usage *state_usage,
311 char *buf)
312{
313 return sysfs_emit(buf, fmt: "%s\n",
314 state->flags & CPUIDLE_FLAG_OFF ? "disabled" : "enabled");
315}
316
317define_one_state_ro(name, show_state_name);
318define_one_state_ro(desc, show_state_desc);
319define_one_state_ro(latency, show_state_exit_latency);
320define_one_state_ro(residency, show_state_target_residency);
321define_one_state_ro(power, show_state_power_usage);
322define_one_state_ro(usage, show_state_usage);
323define_one_state_ro(rejected, show_state_rejected);
324define_one_state_ro(time, show_state_time);
325define_one_state_rw(disable, show_state_disable, store_state_disable);
326define_one_state_ro(above, show_state_above);
327define_one_state_ro(below, show_state_below);
328define_one_state_ro(default_status, show_state_default_status);
329
330static struct attribute *cpuidle_state_default_attrs[] = {
331 &attr_name.attr,
332 &attr_desc.attr,
333 &attr_latency.attr,
334 &attr_residency.attr,
335 &attr_power.attr,
336 &attr_usage.attr,
337 &attr_rejected.attr,
338 &attr_time.attr,
339 &attr_disable.attr,
340 &attr_above.attr,
341 &attr_below.attr,
342 &attr_default_status.attr,
343 NULL
344};
345ATTRIBUTE_GROUPS(cpuidle_state_default);
346
347struct cpuidle_state_kobj {
348 struct cpuidle_state *state;
349 struct cpuidle_state_usage *state_usage;
350 struct completion kobj_unregister;
351 struct kobject kobj;
352 struct cpuidle_device *device;
353};
354
355#ifdef CONFIG_SUSPEND
356#define define_show_state_s2idle_ull_function(_name) \
357static ssize_t show_state_s2idle_##_name(struct cpuidle_state *state, \
358 struct cpuidle_state_usage *state_usage, \
359 char *buf) \
360{ \
361 return sysfs_emit(buf, "%llu\n", state_usage->s2idle_##_name);\
362}
363
364define_show_state_s2idle_ull_function(usage);
365define_show_state_s2idle_ull_function(time);
366
367#define define_one_state_s2idle_ro(_name, show) \
368static struct cpuidle_state_attr attr_s2idle_##_name = \
369 __ATTR(_name, 0444, show, NULL)
370
371define_one_state_s2idle_ro(usage, show_state_s2idle_usage);
372define_one_state_s2idle_ro(time, show_state_s2idle_time);
373
374static struct attribute *cpuidle_state_s2idle_attrs[] = {
375 &attr_s2idle_usage.attr,
376 &attr_s2idle_time.attr,
377 NULL
378};
379
380static const struct attribute_group cpuidle_state_s2idle_group = {
381 .name = "s2idle",
382 .attrs = cpuidle_state_s2idle_attrs,
383};
384
385static void cpuidle_add_s2idle_attr_group(struct cpuidle_state_kobj *kobj)
386{
387 int ret;
388
389 if (!kobj->state->enter_s2idle)
390 return;
391
392 ret = sysfs_create_group(kobj: &kobj->kobj, grp: &cpuidle_state_s2idle_group);
393 if (ret)
394 pr_debug("%s: sysfs attribute group not created\n", __func__);
395}
396
397static void cpuidle_remove_s2idle_attr_group(struct cpuidle_state_kobj *kobj)
398{
399 if (kobj->state->enter_s2idle)
400 sysfs_remove_group(kobj: &kobj->kobj, grp: &cpuidle_state_s2idle_group);
401}
402#else
403static inline void cpuidle_add_s2idle_attr_group(struct cpuidle_state_kobj *kobj) { }
404static inline void cpuidle_remove_s2idle_attr_group(struct cpuidle_state_kobj *kobj) { }
405#endif /* CONFIG_SUSPEND */
406
407#define kobj_to_state_obj(k) container_of(k, struct cpuidle_state_kobj, kobj)
408#define kobj_to_state(k) (kobj_to_state_obj(k)->state)
409#define kobj_to_state_usage(k) (kobj_to_state_obj(k)->state_usage)
410#define kobj_to_device(k) (kobj_to_state_obj(k)->device)
411#define attr_to_stateattr(a) container_of(a, struct cpuidle_state_attr, attr)
412
413static ssize_t cpuidle_state_show(struct kobject *kobj, struct attribute *attr,
414 char *buf)
415{
416 int ret = -EIO;
417 struct cpuidle_state *state = kobj_to_state(kobj);
418 struct cpuidle_state_usage *state_usage = kobj_to_state_usage(kobj);
419 struct cpuidle_state_attr *cattr = attr_to_stateattr(attr);
420
421 if (cattr->show)
422 ret = cattr->show(state, state_usage, buf);
423
424 return ret;
425}
426
427static ssize_t cpuidle_state_store(struct kobject *kobj, struct attribute *attr,
428 const char *buf, size_t size)
429{
430 int ret = -EIO;
431 struct cpuidle_state *state = kobj_to_state(kobj);
432 struct cpuidle_state_usage *state_usage = kobj_to_state_usage(kobj);
433 struct cpuidle_state_attr *cattr = attr_to_stateattr(attr);
434 struct cpuidle_device *dev = kobj_to_device(kobj);
435
436 if (cattr->store)
437 ret = cattr->store(state, state_usage, buf, size);
438
439 /* reset poll time cache */
440 dev->poll_limit_ns = 0;
441
442 return ret;
443}
444
445static const struct sysfs_ops cpuidle_state_sysfs_ops = {
446 .show = cpuidle_state_show,
447 .store = cpuidle_state_store,
448};
449
450static void cpuidle_state_sysfs_release(struct kobject *kobj)
451{
452 struct cpuidle_state_kobj *state_obj = kobj_to_state_obj(kobj);
453
454 complete(&state_obj->kobj_unregister);
455}
456
457static const struct kobj_type ktype_state_cpuidle = {
458 .sysfs_ops = &cpuidle_state_sysfs_ops,
459 .default_groups = cpuidle_state_default_groups,
460 .release = cpuidle_state_sysfs_release,
461};
462
463static inline void cpuidle_free_state_kobj(struct cpuidle_device *device, int i)
464{
465 cpuidle_remove_s2idle_attr_group(kobj: device->kobjs[i]);
466 kobject_put(kobj: &device->kobjs[i]->kobj);
467 wait_for_completion(&device->kobjs[i]->kobj_unregister);
468 kfree(objp: device->kobjs[i]);
469 device->kobjs[i] = NULL;
470}
471
472/**
473 * cpuidle_add_state_sysfs - adds cpuidle states sysfs attributes
474 * @device: the target device
475 */
476static int cpuidle_add_state_sysfs(struct cpuidle_device *device)
477{
478 int i, ret = -ENOMEM;
479 struct cpuidle_state_kobj *kobj;
480 struct cpuidle_device_kobj *kdev = device->kobj_dev;
481 struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev: device);
482
483 /* state statistics */
484 for (i = 0; i < drv->state_count; i++) {
485 kobj = kzalloc(sizeof(struct cpuidle_state_kobj), GFP_KERNEL);
486 if (!kobj) {
487 ret = -ENOMEM;
488 goto error_state;
489 }
490 kobj->state = &drv->states[i];
491 kobj->state_usage = &device->states_usage[i];
492 kobj->device = device;
493 init_completion(x: &kobj->kobj_unregister);
494
495 ret = kobject_init_and_add(kobj: &kobj->kobj, ktype: &ktype_state_cpuidle,
496 parent: &kdev->kobj, fmt: "state%d", i);
497 if (ret) {
498 kobject_put(kobj: &kobj->kobj);
499 kfree(objp: kobj);
500 goto error_state;
501 }
502 cpuidle_add_s2idle_attr_group(kobj);
503 kobject_uevent(kobj: &kobj->kobj, action: KOBJ_ADD);
504 device->kobjs[i] = kobj;
505 }
506
507 return 0;
508
509error_state:
510 for (i = i - 1; i >= 0; i--)
511 cpuidle_free_state_kobj(device, i);
512 return ret;
513}
514
515/**
516 * cpuidle_remove_state_sysfs - removes the cpuidle states sysfs attributes
517 * @device: the target device
518 */
519static void cpuidle_remove_state_sysfs(struct cpuidle_device *device)
520{
521 struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev: device);
522 int i;
523
524 for (i = 0; i < drv->state_count; i++)
525 cpuidle_free_state_kobj(device, i);
526}
527
528#ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS
529#define kobj_to_driver_kobj(k) container_of(k, struct cpuidle_driver_kobj, kobj)
530#define attr_to_driver_attr(a) container_of(a, struct cpuidle_driver_attr, attr)
531
532#define define_one_driver_ro(_name, show) \
533 static struct cpuidle_driver_attr attr_driver_##_name = \
534 __ATTR(_name, 0444, show, NULL)
535
536struct cpuidle_driver_kobj {
537 struct cpuidle_driver *drv;
538 struct completion kobj_unregister;
539 struct kobject kobj;
540};
541
542struct cpuidle_driver_attr {
543 struct attribute attr;
544 ssize_t (*show)(struct cpuidle_driver *, char *);
545 ssize_t (*store)(struct cpuidle_driver *, const char *, size_t);
546};
547
548static ssize_t show_driver_name(struct cpuidle_driver *drv, char *buf)
549{
550 ssize_t ret;
551
552 spin_lock(&cpuidle_driver_lock);
553 ret = sysfs_emit(buf, "%s\n", drv ? drv->name : "none");
554 spin_unlock(&cpuidle_driver_lock);
555
556 return ret;
557}
558
559static void cpuidle_driver_sysfs_release(struct kobject *kobj)
560{
561 struct cpuidle_driver_kobj *driver_kobj = kobj_to_driver_kobj(kobj);
562 complete(&driver_kobj->kobj_unregister);
563}
564
565static ssize_t cpuidle_driver_show(struct kobject *kobj, struct attribute *attr,
566 char *buf)
567{
568 int ret = -EIO;
569 struct cpuidle_driver_kobj *driver_kobj = kobj_to_driver_kobj(kobj);
570 struct cpuidle_driver_attr *dattr = attr_to_driver_attr(attr);
571
572 if (dattr->show)
573 ret = dattr->show(driver_kobj->drv, buf);
574
575 return ret;
576}
577
578static ssize_t cpuidle_driver_store(struct kobject *kobj, struct attribute *attr,
579 const char *buf, size_t size)
580{
581 int ret = -EIO;
582 struct cpuidle_driver_kobj *driver_kobj = kobj_to_driver_kobj(kobj);
583 struct cpuidle_driver_attr *dattr = attr_to_driver_attr(attr);
584
585 if (dattr->store)
586 ret = dattr->store(driver_kobj->drv, buf, size);
587
588 return ret;
589}
590
591define_one_driver_ro(name, show_driver_name);
592
593static const struct sysfs_ops cpuidle_driver_sysfs_ops = {
594 .show = cpuidle_driver_show,
595 .store = cpuidle_driver_store,
596};
597
598static struct attribute *cpuidle_driver_default_attrs[] = {
599 &attr_driver_name.attr,
600 NULL
601};
602ATTRIBUTE_GROUPS(cpuidle_driver_default);
603
604static const struct kobj_type ktype_driver_cpuidle = {
605 .sysfs_ops = &cpuidle_driver_sysfs_ops,
606 .default_groups = cpuidle_driver_default_groups,
607 .release = cpuidle_driver_sysfs_release,
608};
609
610/**
611 * cpuidle_add_driver_sysfs - adds the driver name sysfs attribute
612 * @dev: the target device
613 */
614static int cpuidle_add_driver_sysfs(struct cpuidle_device *dev)
615{
616 struct cpuidle_driver_kobj *kdrv;
617 struct cpuidle_device_kobj *kdev = dev->kobj_dev;
618 struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
619 int ret;
620
621 kdrv = kzalloc(sizeof(*kdrv), GFP_KERNEL);
622 if (!kdrv)
623 return -ENOMEM;
624
625 kdrv->drv = drv;
626 init_completion(&kdrv->kobj_unregister);
627
628 ret = kobject_init_and_add(&kdrv->kobj, &ktype_driver_cpuidle,
629 &kdev->kobj, "driver");
630 if (ret) {
631 kobject_put(&kdrv->kobj);
632 kfree(kdrv);
633 return ret;
634 }
635
636 kobject_uevent(&kdrv->kobj, KOBJ_ADD);
637 dev->kobj_driver = kdrv;
638
639 return ret;
640}
641
642/**
643 * cpuidle_remove_driver_sysfs - removes the driver name sysfs attribute
644 * @dev: the target device
645 */
646static void cpuidle_remove_driver_sysfs(struct cpuidle_device *dev)
647{
648 struct cpuidle_driver_kobj *kdrv = dev->kobj_driver;
649 kobject_put(&kdrv->kobj);
650 wait_for_completion(&kdrv->kobj_unregister);
651 kfree(kdrv);
652}
653#else
654static inline int cpuidle_add_driver_sysfs(struct cpuidle_device *dev)
655{
656 return 0;
657}
658
659static inline void cpuidle_remove_driver_sysfs(struct cpuidle_device *dev)
660{
661 ;
662}
663#endif
664
665/**
666 * cpuidle_add_device_sysfs - adds device specific sysfs attributes
667 * @device: the target device
668 */
669int cpuidle_add_device_sysfs(struct cpuidle_device *device)
670{
671 int ret;
672
673 ret = cpuidle_add_state_sysfs(device);
674 if (ret)
675 return ret;
676
677 ret = cpuidle_add_driver_sysfs(dev: device);
678 if (ret)
679 cpuidle_remove_state_sysfs(device);
680 return ret;
681}
682
683/**
684 * cpuidle_remove_device_sysfs : removes device specific sysfs attributes
685 * @device : the target device
686 */
687void cpuidle_remove_device_sysfs(struct cpuidle_device *device)
688{
689 cpuidle_remove_driver_sysfs(dev: device);
690 cpuidle_remove_state_sysfs(device);
691}
692
693/**
694 * cpuidle_add_sysfs - creates a sysfs instance for the target device
695 * @dev: the target device
696 */
697int cpuidle_add_sysfs(struct cpuidle_device *dev)
698{
699 struct cpuidle_device_kobj *kdev;
700 struct device *cpu_dev = get_cpu_device(cpu: (unsigned long)dev->cpu);
701 int error;
702
703 /*
704 * Return if cpu_device is not setup for this CPU.
705 *
706 * This could happen if the arch did not set up cpu_device
707 * since this CPU is not in cpu_present mask and the
708 * driver did not send a correct CPU mask during registration.
709 * Without this check we would end up passing bogus
710 * value for &cpu_dev->kobj in kobject_init_and_add()
711 */
712 if (!cpu_dev)
713 return -ENODEV;
714
715 kdev = kzalloc(sizeof(*kdev), GFP_KERNEL);
716 if (!kdev)
717 return -ENOMEM;
718 kdev->dev = dev;
719
720 init_completion(x: &kdev->kobj_unregister);
721
722 error = kobject_init_and_add(kobj: &kdev->kobj, ktype: &ktype_cpuidle, parent: &cpu_dev->kobj,
723 fmt: "cpuidle");
724 if (error) {
725 kobject_put(kobj: &kdev->kobj);
726 kfree(objp: kdev);
727 return error;
728 }
729
730 dev->kobj_dev = kdev;
731 kobject_uevent(kobj: &kdev->kobj, action: KOBJ_ADD);
732
733 return 0;
734}
735
736/**
737 * cpuidle_remove_sysfs - deletes a sysfs instance on the target device
738 * @dev: the target device
739 */
740void cpuidle_remove_sysfs(struct cpuidle_device *dev)
741{
742 struct cpuidle_device_kobj *kdev = dev->kobj_dev;
743
744 kobject_put(kobj: &kdev->kobj);
745 wait_for_completion(&kdev->kobj_unregister);
746 kfree(objp: kdev);
747}
748

source code of linux/drivers/cpuidle/sysfs.c