xref: /openbmc/linux/drivers/cpuidle/sysfs.c (revision 2359ccdd) 
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 
21 static unsigned int sysfs_switch;
22 static int __init cpuidle_sysfs_setup(char *unused)
23 {
24 	sysfs_switch = 1;
25 	return 1;
26 }
27 __setup("cpuidle_sysfs_switch", cpuidle_sysfs_setup);
28 
29 static ssize_t show_available_governors(struct device *dev,
30 					struct device_attribute *attr,
31 					char *buf)
32 {
33 	ssize_t i = 0;
34 	struct cpuidle_governor *tmp;
35 
36 	mutex_lock(&cpuidle_lock);
37 	list_for_each_entry(tmp, &cpuidle_governors, governor_list) {
38 		if (i >= (ssize_t) ((PAGE_SIZE/sizeof(char)) -
39 				    CPUIDLE_NAME_LEN - 2))
40 			goto out;
41 		i += scnprintf(&buf[i], CPUIDLE_NAME_LEN, "%s ", tmp->name);
42 	}
43 
44 out:
45 	i+= sprintf(&buf[i], "\n");
46 	mutex_unlock(&cpuidle_lock);
47 	return i;
48 }
49 
50 static ssize_t show_current_driver(struct device *dev,
51 				   struct device_attribute *attr,
52 				   char *buf)
53 {
54 	ssize_t ret;
55 	struct cpuidle_driver *drv;
56 
57 	spin_lock(&cpuidle_driver_lock);
58 	drv = cpuidle_get_driver();
59 	if (drv)
60 		ret = sprintf(buf, "%s\n", drv->name);
61 	else
62 		ret = sprintf(buf, "none\n");
63 	spin_unlock(&cpuidle_driver_lock);
64 
65 	return ret;
66 }
67 
68 static ssize_t show_current_governor(struct device *dev,
69 				     struct device_attribute *attr,
70 				     char *buf)
71 {
72 	ssize_t ret;
73 
74 	mutex_lock(&cpuidle_lock);
75 	if (cpuidle_curr_governor)
76 		ret = sprintf(buf, "%s\n", cpuidle_curr_governor->name);
77 	else
78 		ret = sprintf(buf, "none\n");
79 	mutex_unlock(&cpuidle_lock);
80 
81 	return ret;
82 }
83 
84 static ssize_t store_current_governor(struct device *dev,
85 				      struct device_attribute *attr,
86 				      const char *buf, size_t count)
87 {
88 	char gov_name[CPUIDLE_NAME_LEN];
89 	int ret = -EINVAL;
90 	size_t len = count;
91 	struct cpuidle_governor *gov;
92 
93 	if (!len || len >= sizeof(gov_name))
94 		return -EINVAL;
95 
96 	memcpy(gov_name, buf, len);
97 	gov_name[len] = '\0';
98 	if (gov_name[len - 1] == '\n')
99 		gov_name[--len] = '\0';
100 
101 	mutex_lock(&cpuidle_lock);
102 
103 	list_for_each_entry(gov, &cpuidle_governors, governor_list) {
104 		if (strlen(gov->name) == len && !strcmp(gov->name, gov_name)) {
105 			ret = cpuidle_switch_governor(gov);
106 			break;
107 		}
108 	}
109 
110 	mutex_unlock(&cpuidle_lock);
111 
112 	if (ret)
113 		return ret;
114 	else
115 		return count;
116 }
117 
118 static DEVICE_ATTR(current_driver, 0444, show_current_driver, NULL);
119 static DEVICE_ATTR(current_governor_ro, 0444, show_current_governor, NULL);
120 
121 static struct attribute *cpuidle_default_attrs[] = {
122 	&dev_attr_current_driver.attr,
123 	&dev_attr_current_governor_ro.attr,
124 	NULL
125 };
126 
127 static DEVICE_ATTR(available_governors, 0444, show_available_governors, NULL);
128 static DEVICE_ATTR(current_governor, 0644, show_current_governor,
129 		   store_current_governor);
130 
131 static struct attribute *cpuidle_switch_attrs[] = {
132 	&dev_attr_available_governors.attr,
133 	&dev_attr_current_driver.attr,
134 	&dev_attr_current_governor.attr,
135 	NULL
136 };
137 
138 static struct attribute_group cpuidle_attr_group = {
139 	.attrs = cpuidle_default_attrs,
140 	.name = "cpuidle",
141 };
142 
143 /**
144  * cpuidle_add_interface - add CPU global sysfs attributes
145  */
146 int cpuidle_add_interface(struct device *dev)
147 {
148 	if (sysfs_switch)
149 		cpuidle_attr_group.attrs = cpuidle_switch_attrs;
150 
151 	return sysfs_create_group(&dev->kobj, &cpuidle_attr_group);
152 }
153 
154 /**
155  * cpuidle_remove_interface - remove CPU global sysfs attributes
156  */
157 void cpuidle_remove_interface(struct device *dev)
158 {
159 	sysfs_remove_group(&dev->kobj, &cpuidle_attr_group);
160 }
161 
162 struct cpuidle_attr {
163 	struct attribute attr;
164 	ssize_t (*show)(struct cpuidle_device *, char *);
165 	ssize_t (*store)(struct cpuidle_device *, const char *, size_t count);
166 };
167 
168 #define define_one_ro(_name, show) \
169 	static struct cpuidle_attr attr_##_name = __ATTR(_name, 0444, show, NULL)
170 #define define_one_rw(_name, show, store) \
171 	static struct cpuidle_attr attr_##_name = __ATTR(_name, 0644, show, store)
172 
173 #define attr_to_cpuidleattr(a) container_of(a, struct cpuidle_attr, attr)
174 
175 struct cpuidle_device_kobj {
176 	struct cpuidle_device *dev;
177 	struct completion kobj_unregister;
178 	struct kobject kobj;
179 };
180 
181 static inline struct cpuidle_device *to_cpuidle_device(struct kobject *kobj)
182 {
183 	struct cpuidle_device_kobj *kdev =
184 		container_of(kobj, struct cpuidle_device_kobj, kobj);
185 
186 	return kdev->dev;
187 }
188 
189 static ssize_t cpuidle_show(struct kobject *kobj, struct attribute *attr,
190 			    char *buf)
191 {
192 	int ret = -EIO;
193 	struct cpuidle_device *dev = to_cpuidle_device(kobj);
194 	struct cpuidle_attr *cattr = attr_to_cpuidleattr(attr);
195 
196 	if (cattr->show) {
197 		mutex_lock(&cpuidle_lock);
198 		ret = cattr->show(dev, buf);
199 		mutex_unlock(&cpuidle_lock);
200 	}
201 	return ret;
202 }
203 
204 static ssize_t cpuidle_store(struct kobject *kobj, struct attribute *attr,
205 			     const char *buf, size_t count)
206 {
207 	int ret = -EIO;
208 	struct cpuidle_device *dev = to_cpuidle_device(kobj);
209 	struct cpuidle_attr *cattr = attr_to_cpuidleattr(attr);
210 
211 	if (cattr->store) {
212 		mutex_lock(&cpuidle_lock);
213 		ret = cattr->store(dev, buf, count);
214 		mutex_unlock(&cpuidle_lock);
215 	}
216 	return ret;
217 }
218 
219 static const struct sysfs_ops cpuidle_sysfs_ops = {
220 	.show = cpuidle_show,
221 	.store = cpuidle_store,
222 };
223 
224 static void cpuidle_sysfs_release(struct kobject *kobj)
225 {
226 	struct cpuidle_device_kobj *kdev =
227 		container_of(kobj, struct cpuidle_device_kobj, kobj);
228 
229 	complete(&kdev->kobj_unregister);
230 }
231 
232 static struct kobj_type ktype_cpuidle = {
233 	.sysfs_ops = &cpuidle_sysfs_ops,
234 	.release = cpuidle_sysfs_release,
235 };
236 
237 struct cpuidle_state_attr {
238 	struct attribute attr;
239 	ssize_t (*show)(struct cpuidle_state *, \
240 					struct cpuidle_state_usage *, char *);
241 	ssize_t (*store)(struct cpuidle_state *, \
242 			struct cpuidle_state_usage *, const char *, size_t);
243 };
244 
245 #define define_one_state_ro(_name, show) \
246 static struct cpuidle_state_attr attr_##_name = __ATTR(_name, 0444, show, NULL)
247 
248 #define define_one_state_rw(_name, show, store) \
249 static struct cpuidle_state_attr attr_##_name = __ATTR(_name, 0644, show, store)
250 
251 #define define_show_state_function(_name) \
252 static ssize_t show_state_##_name(struct cpuidle_state *state, \
253 			 struct cpuidle_state_usage *state_usage, char *buf) \
254 { \
255 	return sprintf(buf, "%u\n", state->_name);\
256 }
257 
258 #define define_store_state_ull_function(_name) \
259 static ssize_t store_state_##_name(struct cpuidle_state *state, \
260 				   struct cpuidle_state_usage *state_usage, \
261 				   const char *buf, size_t size)	\
262 { \
263 	unsigned long long value; \
264 	int err; \
265 	if (!capable(CAP_SYS_ADMIN)) \
266 		return -EPERM; \
267 	err = kstrtoull(buf, 0, &value); \
268 	if (err) \
269 		return err; \
270 	if (value) \
271 		state_usage->_name = 1; \
272 	else \
273 		state_usage->_name = 0; \
274 	return size; \
275 }
276 
277 #define define_show_state_ull_function(_name) \
278 static ssize_t show_state_##_name(struct cpuidle_state *state, \
279 				  struct cpuidle_state_usage *state_usage, \
280 				  char *buf)				\
281 { \
282 	return sprintf(buf, "%llu\n", state_usage->_name);\
283 }
284 
285 #define define_show_state_str_function(_name) \
286 static ssize_t show_state_##_name(struct cpuidle_state *state, \
287 				  struct cpuidle_state_usage *state_usage, \
288 				  char *buf)				\
289 { \
290 	if (state->_name[0] == '\0')\
291 		return sprintf(buf, "<null>\n");\
292 	return sprintf(buf, "%s\n", state->_name);\
293 }
294 
295 define_show_state_function(exit_latency)
296 define_show_state_function(target_residency)
297 define_show_state_function(power_usage)
298 define_show_state_ull_function(usage)
299 define_show_state_ull_function(time)
300 define_show_state_str_function(name)
301 define_show_state_str_function(desc)
302 define_show_state_ull_function(disable)
303 define_store_state_ull_function(disable)
304 
305 define_one_state_ro(name, show_state_name);
306 define_one_state_ro(desc, show_state_desc);
307 define_one_state_ro(latency, show_state_exit_latency);
308 define_one_state_ro(residency, show_state_target_residency);
309 define_one_state_ro(power, show_state_power_usage);
310 define_one_state_ro(usage, show_state_usage);
311 define_one_state_ro(time, show_state_time);
312 define_one_state_rw(disable, show_state_disable, store_state_disable);
313 
314 static struct attribute *cpuidle_state_default_attrs[] = {
315 	&attr_name.attr,
316 	&attr_desc.attr,
317 	&attr_latency.attr,
318 	&attr_residency.attr,
319 	&attr_power.attr,
320 	&attr_usage.attr,
321 	&attr_time.attr,
322 	&attr_disable.attr,
323 	NULL
324 };
325 
326 struct cpuidle_state_kobj {
327 	struct cpuidle_state *state;
328 	struct cpuidle_state_usage *state_usage;
329 	struct completion kobj_unregister;
330 	struct kobject kobj;
331 };
332 
333 #ifdef CONFIG_SUSPEND
334 #define define_show_state_s2idle_ull_function(_name) \
335 static ssize_t show_state_s2idle_##_name(struct cpuidle_state *state, \
336 					 struct cpuidle_state_usage *state_usage, \
337 					 char *buf)				\
338 { \
339 	return sprintf(buf, "%llu\n", state_usage->s2idle_##_name);\
340 }
341 
342 define_show_state_s2idle_ull_function(usage);
343 define_show_state_s2idle_ull_function(time);
344 
345 #define define_one_state_s2idle_ro(_name, show) \
346 static struct cpuidle_state_attr attr_s2idle_##_name = \
347 	__ATTR(_name, 0444, show, NULL)
348 
349 define_one_state_s2idle_ro(usage, show_state_s2idle_usage);
350 define_one_state_s2idle_ro(time, show_state_s2idle_time);
351 
352 static struct attribute *cpuidle_state_s2idle_attrs[] = {
353 	&attr_s2idle_usage.attr,
354 	&attr_s2idle_time.attr,
355 	NULL
356 };
357 
358 static const struct attribute_group cpuidle_state_s2idle_group = {
359 	.name	= "s2idle",
360 	.attrs	= cpuidle_state_s2idle_attrs,
361 };
362 
363 static void cpuidle_add_s2idle_attr_group(struct cpuidle_state_kobj *kobj)
364 {
365 	int ret;
366 
367 	if (!kobj->state->enter_s2idle)
368 		return;
369 
370 	ret = sysfs_create_group(&kobj->kobj, &cpuidle_state_s2idle_group);
371 	if (ret)
372 		pr_debug("%s: sysfs attribute group not created\n", __func__);
373 }
374 
375 static void cpuidle_remove_s2idle_attr_group(struct cpuidle_state_kobj *kobj)
376 {
377 	if (kobj->state->enter_s2idle)
378 		sysfs_remove_group(&kobj->kobj, &cpuidle_state_s2idle_group);
379 }
380 #else
381 static inline void cpuidle_add_s2idle_attr_group(struct cpuidle_state_kobj *kobj) { }
382 static inline void cpuidle_remove_s2idle_attr_group(struct cpuidle_state_kobj *kobj) { }
383 #endif /* CONFIG_SUSPEND */
384 
385 #define kobj_to_state_obj(k) container_of(k, struct cpuidle_state_kobj, kobj)
386 #define kobj_to_state(k) (kobj_to_state_obj(k)->state)
387 #define kobj_to_state_usage(k) (kobj_to_state_obj(k)->state_usage)
388 #define attr_to_stateattr(a) container_of(a, struct cpuidle_state_attr, attr)
389 
390 static ssize_t cpuidle_state_show(struct kobject *kobj, struct attribute *attr,
391 				  char * buf)
392 {
393 	int ret = -EIO;
394 	struct cpuidle_state *state = kobj_to_state(kobj);
395 	struct cpuidle_state_usage *state_usage = kobj_to_state_usage(kobj);
396 	struct cpuidle_state_attr * cattr = attr_to_stateattr(attr);
397 
398 	if (cattr->show)
399 		ret = cattr->show(state, state_usage, buf);
400 
401 	return ret;
402 }
403 
404 static ssize_t cpuidle_state_store(struct kobject *kobj, struct attribute *attr,
405 				   const char *buf, size_t size)
406 {
407 	int ret = -EIO;
408 	struct cpuidle_state *state = kobj_to_state(kobj);
409 	struct cpuidle_state_usage *state_usage = kobj_to_state_usage(kobj);
410 	struct cpuidle_state_attr *cattr = attr_to_stateattr(attr);
411 
412 	if (cattr->store)
413 		ret = cattr->store(state, state_usage, buf, size);
414 
415 	return ret;
416 }
417 
418 static const struct sysfs_ops cpuidle_state_sysfs_ops = {
419 	.show = cpuidle_state_show,
420 	.store = cpuidle_state_store,
421 };
422 
423 static void cpuidle_state_sysfs_release(struct kobject *kobj)
424 {
425 	struct cpuidle_state_kobj *state_obj = kobj_to_state_obj(kobj);
426 
427 	complete(&state_obj->kobj_unregister);
428 }
429 
430 static struct kobj_type ktype_state_cpuidle = {
431 	.sysfs_ops = &cpuidle_state_sysfs_ops,
432 	.default_attrs = cpuidle_state_default_attrs,
433 	.release = cpuidle_state_sysfs_release,
434 };
435 
436 static inline void cpuidle_free_state_kobj(struct cpuidle_device *device, int i)
437 {
438 	cpuidle_remove_s2idle_attr_group(device->kobjs[i]);
439 	kobject_put(&device->kobjs[i]->kobj);
440 	wait_for_completion(&device->kobjs[i]->kobj_unregister);
441 	kfree(device->kobjs[i]);
442 	device->kobjs[i] = NULL;
443 }
444 
445 /**
446  * cpuidle_add_state_sysfs - adds cpuidle states sysfs attributes
447  * @device: the target device
448  */
449 static int cpuidle_add_state_sysfs(struct cpuidle_device *device)
450 {
451 	int i, ret = -ENOMEM;
452 	struct cpuidle_state_kobj *kobj;
453 	struct cpuidle_device_kobj *kdev = device->kobj_dev;
454 	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(device);
455 
456 	/* state statistics */
457 	for (i = 0; i < drv->state_count; i++) {
458 		kobj = kzalloc(sizeof(struct cpuidle_state_kobj), GFP_KERNEL);
459 		if (!kobj) {
460 			ret = -ENOMEM;
461 			goto error_state;
462 		}
463 		kobj->state = &drv->states[i];
464 		kobj->state_usage = &device->states_usage[i];
465 		init_completion(&kobj->kobj_unregister);
466 
467 		ret = kobject_init_and_add(&kobj->kobj, &ktype_state_cpuidle,
468 					   &kdev->kobj, "state%d", i);
469 		if (ret) {
470 			kfree(kobj);
471 			goto error_state;
472 		}
473 		cpuidle_add_s2idle_attr_group(kobj);
474 		kobject_uevent(&kobj->kobj, KOBJ_ADD);
475 		device->kobjs[i] = kobj;
476 	}
477 
478 	return 0;
479 
480 error_state:
481 	for (i = i - 1; i >= 0; i--)
482 		cpuidle_free_state_kobj(device, i);
483 	return ret;
484 }
485 
486 /**
487  * cpuidle_remove_driver_sysfs - removes the cpuidle states sysfs attributes
488  * @device: the target device
489  */
490 static void cpuidle_remove_state_sysfs(struct cpuidle_device *device)
491 {
492 	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(device);
493 	int i;
494 
495 	for (i = 0; i < drv->state_count; i++)
496 		cpuidle_free_state_kobj(device, i);
497 }
498 
499 #ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS
500 #define kobj_to_driver_kobj(k) container_of(k, struct cpuidle_driver_kobj, kobj)
501 #define attr_to_driver_attr(a) container_of(a, struct cpuidle_driver_attr, attr)
502 
503 #define define_one_driver_ro(_name, show)                       \
504 	static struct cpuidle_driver_attr attr_driver_##_name = \
505 		__ATTR(_name, 0444, show, NULL)
506 
507 struct cpuidle_driver_kobj {
508 	struct cpuidle_driver *drv;
509 	struct completion kobj_unregister;
510 	struct kobject kobj;
511 };
512 
513 struct cpuidle_driver_attr {
514 	struct attribute attr;
515 	ssize_t (*show)(struct cpuidle_driver *, char *);
516 	ssize_t (*store)(struct cpuidle_driver *, const char *, size_t);
517 };
518 
519 static ssize_t show_driver_name(struct cpuidle_driver *drv, char *buf)
520 {
521 	ssize_t ret;
522 
523 	spin_lock(&cpuidle_driver_lock);
524 	ret = sprintf(buf, "%s\n", drv ? drv->name : "none");
525 	spin_unlock(&cpuidle_driver_lock);
526 
527 	return ret;
528 }
529 
530 static void cpuidle_driver_sysfs_release(struct kobject *kobj)
531 {
532 	struct cpuidle_driver_kobj *driver_kobj = kobj_to_driver_kobj(kobj);
533 	complete(&driver_kobj->kobj_unregister);
534 }
535 
536 static ssize_t cpuidle_driver_show(struct kobject *kobj, struct attribute *attr,
537 				   char *buf)
538 {
539 	int ret = -EIO;
540 	struct cpuidle_driver_kobj *driver_kobj = kobj_to_driver_kobj(kobj);
541 	struct cpuidle_driver_attr *dattr = attr_to_driver_attr(attr);
542 
543 	if (dattr->show)
544 		ret = dattr->show(driver_kobj->drv, buf);
545 
546 	return ret;
547 }
548 
549 static ssize_t cpuidle_driver_store(struct kobject *kobj, struct attribute *attr,
550 				    const char *buf, size_t size)
551 {
552 	int ret = -EIO;
553 	struct cpuidle_driver_kobj *driver_kobj = kobj_to_driver_kobj(kobj);
554 	struct cpuidle_driver_attr *dattr = attr_to_driver_attr(attr);
555 
556 	if (dattr->store)
557 		ret = dattr->store(driver_kobj->drv, buf, size);
558 
559 	return ret;
560 }
561 
562 define_one_driver_ro(name, show_driver_name);
563 
564 static const struct sysfs_ops cpuidle_driver_sysfs_ops = {
565 	.show = cpuidle_driver_show,
566 	.store = cpuidle_driver_store,
567 };
568 
569 static struct attribute *cpuidle_driver_default_attrs[] = {
570 	&attr_driver_name.attr,
571 	NULL
572 };
573 
574 static struct kobj_type ktype_driver_cpuidle = {
575 	.sysfs_ops = &cpuidle_driver_sysfs_ops,
576 	.default_attrs = cpuidle_driver_default_attrs,
577 	.release = cpuidle_driver_sysfs_release,
578 };
579 
580 /**
581  * cpuidle_add_driver_sysfs - adds the driver name sysfs attribute
582  * @device: the target device
583  */
584 static int cpuidle_add_driver_sysfs(struct cpuidle_device *dev)
585 {
586 	struct cpuidle_driver_kobj *kdrv;
587 	struct cpuidle_device_kobj *kdev = dev->kobj_dev;
588 	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
589 	int ret;
590 
591 	kdrv = kzalloc(sizeof(*kdrv), GFP_KERNEL);
592 	if (!kdrv)
593 		return -ENOMEM;
594 
595 	kdrv->drv = drv;
596 	init_completion(&kdrv->kobj_unregister);
597 
598 	ret = kobject_init_and_add(&kdrv->kobj, &ktype_driver_cpuidle,
599 				   &kdev->kobj, "driver");
600 	if (ret) {
601 		kfree(kdrv);
602 		return ret;
603 	}
604 
605 	kobject_uevent(&kdrv->kobj, KOBJ_ADD);
606 	dev->kobj_driver = kdrv;
607 
608 	return ret;
609 }
610 
611 /**
612  * cpuidle_remove_driver_sysfs - removes the driver name sysfs attribute
613  * @device: the target device
614  */
615 static void cpuidle_remove_driver_sysfs(struct cpuidle_device *dev)
616 {
617 	struct cpuidle_driver_kobj *kdrv = dev->kobj_driver;
618 	kobject_put(&kdrv->kobj);
619 	wait_for_completion(&kdrv->kobj_unregister);
620 	kfree(kdrv);
621 }
622 #else
623 static inline int cpuidle_add_driver_sysfs(struct cpuidle_device *dev)
624 {
625 	return 0;
626 }
627 
628 static inline void cpuidle_remove_driver_sysfs(struct cpuidle_device *dev)
629 {
630 	;
631 }
632 #endif
633 
634 /**
635  * cpuidle_add_device_sysfs - adds device specific sysfs attributes
636  * @device: the target device
637  */
638 int cpuidle_add_device_sysfs(struct cpuidle_device *device)
639 {
640 	int ret;
641 
642 	ret = cpuidle_add_state_sysfs(device);
643 	if (ret)
644 		return ret;
645 
646 	ret = cpuidle_add_driver_sysfs(device);
647 	if (ret)
648 		cpuidle_remove_state_sysfs(device);
649 	return ret;
650 }
651 
652 /**
653  * cpuidle_remove_device_sysfs : removes device specific sysfs attributes
654  * @device : the target device
655  */
656 void cpuidle_remove_device_sysfs(struct cpuidle_device *device)
657 {
658 	cpuidle_remove_driver_sysfs(device);
659 	cpuidle_remove_state_sysfs(device);
660 }
661 
662 /**
663  * cpuidle_add_sysfs - creates a sysfs instance for the target device
664  * @dev: the target device
665  */
666 int cpuidle_add_sysfs(struct cpuidle_device *dev)
667 {
668 	struct cpuidle_device_kobj *kdev;
669 	struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu);
670 	int error;
671 
672 	/*
673 	 * Return if cpu_device is not setup for this CPU.
674 	 *
675 	 * This could happen if the arch did not set up cpu_device
676 	 * since this CPU is not in cpu_present mask and the
677 	 * driver did not send a correct CPU mask during registration.
678 	 * Without this check we would end up passing bogus
679 	 * value for &cpu_dev->kobj in kobject_init_and_add()
680 	 */
681 	if (!cpu_dev)
682 		return -ENODEV;
683 
684 	kdev = kzalloc(sizeof(*kdev), GFP_KERNEL);
685 	if (!kdev)
686 		return -ENOMEM;
687 	kdev->dev = dev;
688 	dev->kobj_dev = kdev;
689 
690 	init_completion(&kdev->kobj_unregister);
691 
692 	error = kobject_init_and_add(&kdev->kobj, &ktype_cpuidle, &cpu_dev->kobj,
693 				   "cpuidle");
694 	if (error) {
695 		kfree(kdev);
696 		return error;
697 	}
698 
699 	kobject_uevent(&kdev->kobj, KOBJ_ADD);
700 
701 	return 0;
702 }
703 
704 /**
705  * cpuidle_remove_sysfs - deletes a sysfs instance on the target device
706  * @dev: the target device
707  */
708 void cpuidle_remove_sysfs(struct cpuidle_device *dev)
709 {
710 	struct cpuidle_device_kobj *kdev = dev->kobj_dev;
711 
712 	kobject_put(&kdev->kobj);
713 	wait_for_completion(&kdev->kobj_unregister);
714 	kfree(kdev);
715 }
716