summaryrefslogtreecommitdiffstats
path: root/drivers/cpuidle/sysfs.c
blob: 7729cf622d1ee2935e3ba0769dc208ac6929666a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
/*
 * sysfs.c - sysfs support
 *
 * (C) 2006-2007 Shaohua Li <shaohua.li@intel.com>
 *
 * This code is licenced under the GPL.
 */

#include <linux/kernel.h>
#include <linux/cpuidle.h>
#include <linux/sysfs.h>
#include <linux/slab.h>
#include <linux/cpu.h>
#include <linux/completion.h>
#include <linux/capability.h>
#include <linux/device.h>
#include <linux/kobject.h>

#include "cpuidle.h"

static unsigned int sysfs_switch;
static int __init cpuidle_sysfs_setup(char *unused)
{
	sysfs_switch = 1;
	return 1;
}
__setup("cpuidle_sysfs_switch", cpuidle_sysfs_setup);

static ssize_t show_available_governors(struct device *dev,
					struct device_attribute *attr,
					char *buf)
{
	ssize_t i = 0;
	struct cpuidle_governor *tmp;

	mutex_lock(&cpuidle_lock);
	list_for_each_entry(tmp, &cpuidle_governors, governor_list) {
		if (i >= (ssize_t) ((PAGE_SIZE/sizeof(char)) -
				    CPUIDLE_NAME_LEN - 2))
			goto out;
		i += scnprintf(&buf[i], CPUIDLE_NAME_LEN, "%s ", tmp->name);
	}

out:
	i+= sprintf(&buf[i], "\n");
	mutex_unlock(&cpuidle_lock);
	return i;
}

static ssize_t show_current_driver(struct device *dev,
				   struct device_attribute *attr,
				   char *buf)
{
	ssize_t ret;
	struct cpuidle_driver *drv;

	spin_lock(&cpuidle_driver_lock);
	drv = cpuidle_get_driver();
	if (drv)
		ret = sprintf(buf, "%s\n", drv->name);
	else
		ret = sprintf(buf, "none\n");
	spin_unlock(&cpuidle_driver_lock);

	return ret;
}

static ssize_t show_current_governor(struct device *dev,
				     struct device_attribute *attr,
				     char *buf)
{
	ssize_t ret;

	mutex_lock(&cpuidle_lock);
	if (cpuidle_curr_governor)
		ret = sprintf(buf, "%s\n", cpuidle_curr_governor->name);
	else
		ret = sprintf(buf, "none\n");
	mutex_unlock(&cpuidle_lock);

	return ret;
}

static ssize_t store_current_governor(struct device *dev,
				      struct device_attribute *attr,
				      const char *buf, size_t count)
{
	char gov_name[CPUIDLE_NAME_LEN];
	int ret = -EINVAL;
	size_t len = count;
	struct cpuidle_governor *gov;

	if (!len || len >= sizeof(gov_name))
		return -EINVAL;

	memcpy(gov_name, buf, len);
	gov_name[len] = '\0';
	if (gov_name[len - 1] == '\n')
		gov_name[--len] = '\0';

	mutex_lock(&cpuidle_lock);

	list_for_each_entry(gov, &cpuidle_governors, governor_list) {
		if (strlen(gov->name) == len && !strcmp(gov->name, gov_name)) {
			ret = cpuidle_switch_governor(gov);
			break;
		}
	}

	mutex_unlock(&cpuidle_lock);

	if (ret)
		return ret;
	else
		return count;
}

static DEVICE_ATTR(current_driver, 0444, show_current_driver, NULL);
static DEVICE_ATTR(current_governor_ro, 0444, show_current_governor, NULL);

static struct attribute *cpuidle_default_attrs[] = {
	&dev_attr_current_driver.attr,
	&dev_attr_current_governor_ro.attr,
	NULL
};

static DEVICE_ATTR(available_governors, 0444, show_available_governors, NULL);
static DEVICE_ATTR(current_governor, 0644, show_current_governor,
		   store_current_governor);

static struct attribute *cpuidle_switch_attrs[] = {
	&dev_attr_available_governors.attr,
	&dev_attr_current_driver.attr,
	&dev_attr_current_governor.attr,
	NULL
};

static struct attribute_group cpuidle_attr_group = {
	.attrs = cpuidle_default_attrs,
	.name = "cpuidle",
};

/**
 * cpuidle_add_interface - add CPU global sysfs attributes
 * @dev: the target device
 */
int cpuidle_add_interface(struct device *dev)
{
	if (sysfs_switch)
		cpuidle_attr_group.attrs = cpuidle_switch_attrs;

	return sysfs_create_group(&dev->kobj, &cpuidle_attr_group);
}

/**
 * cpuidle_remove_interface - remove CPU global sysfs attributes
 * @dev: the target device
 */
void cpuidle_remove_interface(struct device *dev)
{
	sysfs_remove_group(&dev->kobj, &cpuidle_attr_group);
}

struct cpuidle_attr {
	struct attribute attr;
	ssize_t (*show)(struct cpuidle_device *, char *);
	ssize_t (*store)(struct cpuidle_device *, const char *, size_t count);
};

#define attr_to_cpuidleattr(a) container_of(a, struct cpuidle_attr, attr)

struct cpuidle_device_kobj {
	struct cpuidle_device *dev;
	struct completion kobj_unregister;
	struct kobject kobj;
};

static inline struct cpuidle_device *to_cpuidle_device(struct kobject *kobj)
{
	struct cpuidle_device_kobj *kdev =
		container_of(kobj, struct cpuidle_device_kobj, kobj);

	return kdev->dev;
}

static ssize_t cpuidle_show(struct kobject *kobj, struct attribute *attr,
			    char *buf)
{
	int ret = -EIO;
	struct cpuidle_device *dev = to_cpuidle_device(kobj);
	struct cpuidle_attr *cattr = attr_to_cpuidleattr(attr);

	if (cattr->show) {
		mutex_lock(&cpuidle_lock);
		ret = cattr->show(dev, buf);
		mutex_unlock(&cpuidle_lock);
	}
	return ret;
}

static ssize_t cpuidle_store(struct kobject *kobj, struct attribute *attr,
			     const char *buf, size_t count)
{
	int ret = -EIO;
	struct cpuidle_device *dev = to_cpuidle_device(kobj);
	struct cpuidle_attr *cattr = attr_to_cpuidleattr(attr);

	if (cattr->store) {
		mutex_lock(&cpuidle_lock);
		ret = cattr->store(dev, buf, count);
		mutex_unlock(&cpuidle_lock);
	}
	return ret;
}

static const struct sysfs_ops cpuidle_sysfs_ops = {
	.show = cpuidle_show,
	.store = cpuidle_store,
};

static void cpuidle_sysfs_release(struct kobject *kobj)
{
	struct cpuidle_device_kobj *kdev =
		container_of(kobj, struct cpuidle_device_kobj, kobj);

	complete(&kdev->kobj_unregister);
}

static struct kobj_type ktype_cpuidle = {
	.sysfs_ops = &cpuidle_sysfs_ops,
	.release = cpuidle_sysfs_release,
};

struct cpuidle_state_attr {
	struct attribute attr;
	ssize_t (*show)(struct cpuidle_state *, \
					struct cpuidle_state_usage *, char *);
	ssize_t (*store)(struct cpuidle_state *, \
			struct cpuidle_state_usage *, const char *, size_t);
};

#define define_one_state_ro(_name, show) \
static struct cpuidle_state_attr attr_##_name = __ATTR(_name, 0444, show, NULL)

#define define_one_state_rw(_name, show, store) \
static struct cpuidle_state_attr attr_##_name = __ATTR(_name, 0644, show, store)

#define define_show_state_function(_name) \
static ssize_t show_state_##_name(struct cpuidle_state *state, \
			 struct cpuidle_state_usage *state_usage, char *buf) \
{ \
	return sprintf(buf, "%u\n", state->_name);\
}

#define define_show_state_ull_function(_name) \
static ssize_t show_state_##_name(struct cpuidle_state *state, \
				  struct cpuidle_state_usage *state_usage, \
				  char *buf)				\
{ \
	return sprintf(buf, "%llu\n", state_usage->_name);\
}

#define define_show_state_str_function(_name) \
static ssize_t show_state_##_name(struct cpuidle_state *state, \
				  struct cpuidle_state_usage *state_usage, \
				  char *buf)				\
{ \
	if (state->_name[0] == '\0')\
		return sprintf(buf, "<null>\n");\
	return sprintf(buf, "%s\n", state->_name);\
}

#define define_show_state_time_function(_name) \
static ssize_t show_state_##_name(struct cpuidle_state *state, \
				  struct cpuidle_state_usage *state_usage, \
				  char *buf) \
{ \
	return sprintf(buf, "%llu\n", ktime_to_us(state->_name##_ns)); \
}

define_show_state_time_function(exit_latency)
define_show_state_time_function(target_residency)
define_show_state_function(power_usage)
define_show_state_ull_function(usage)
define_show_state_str_function(name)
define_show_state_str_function(desc)
define_show_state_ull_function(above)
define_show_state_ull_function(below)

static ssize_t show_state_time(struct cpuidle_state *state,
			       struct cpuidle_state_usage *state_usage,
			       char *buf)
{
	return sprintf(buf, "%llu\n", ktime_to_us(state_usage->time_ns));
}

static ssize_t show_state_disable(struct cpuidle_state *state,
				  struct cpuidle_state_usage *state_usage,
				  char *buf)
{
	return sprintf(buf, "%llu\n",
		       state_usage->disable & CPUIDLE_STATE_DISABLED_BY_USER);
}

static ssize_t store_state_disable(struct cpuidle_state *state,
				   struct cpuidle_state_usage *state_usage,
				   const char *buf, size_t size)
{
	unsigned int value;
	int err;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	err = kstrtouint(buf, 0, &value);
	if (err)
		return err;

	if (value)
		state_usage->disable |= CPUIDLE_STATE_DISABLED_BY_USER;
	else
		state_usage->disable &= ~CPUIDLE_STATE_DISABLED_BY_USER;

	return size;
}

static ssize_t show_state_default_status(struct cpuidle_state *state,
					  struct cpuidle_state_usage *state_usage,
					  char *buf)
{
	return sprintf(buf, "%s\n",
		       state->flags & CPUIDLE_FLAG_OFF ? "disabled" : "enabled");
}

define_one_state_ro(name, show_state_name);
define_one_state_ro(desc, show_state_desc);
define_one_state_ro(latency, show_state_exit_latency);
define_one_state_ro(residency, show_state_target_residency);
define_one_state_ro(power, show_state_power_usage);
define_one_state_ro(usage, show_state_usage);
define_one_state_ro(time, show_state_time);
define_one_state_rw(disable, show_state_disable, store_state_disable);
define_one_state_ro(above, show_state_above);
define_one_state_ro(below, show_state_below);
define_one_state_ro(default_status, show_state_default_status);

static struct attribute *cpuidle_state_default_attrs[] = {
	&attr_name.attr,
	&attr_desc.attr,
	&attr_latency.attr,
	&attr_residency.attr,
	&attr_power.attr,
	&attr_usage.attr,
	&attr_time.attr,
	&attr_disable.attr,
	&attr_above.attr,
	&attr_below.attr,
	&attr_default_status.attr,
	NULL
};

struct cpuidle_state_kobj {
	struct cpuidle_state *state;
	struct cpuidle_state_usage *state_usage;
	struct completion kobj_unregister;
	struct kobject kobj;
	struct cpuidle_device *device;
};

#ifdef CONFIG_SUSPEND
#define define_show_state_s2idle_ull_function(_name) \
static ssize_t show_state_s2idle_##_name(struct cpuidle_state *state, \
					 struct cpuidle_state_usage *state_usage, \
					 char *buf)				\
{ \
	return sprintf(buf, "%llu\n", state_usage->s2idle_##_name);\
}

define_show_state_s2idle_ull_function(usage);
define_show_state_s2idle_ull_function(time);

#define define_one_state_s2idle_ro(_name, show) \
static struct cpuidle_state_attr attr_s2idle_##_name = \
	__ATTR(_name, 0444, show, NULL)

define_one_state_s2idle_ro(usage, show_state_s2idle_usage);
define_one_state_s2idle_ro(time, show_state_s2idle_time);

static struct attribute *cpuidle_state_s2idle_attrs[] = {
	&attr_s2idle_usage.attr,
	&attr_s2idle_time.attr,
	NULL
};

static const struct attribute_group cpuidle_state_s2idle_group = {
	.name	= "s2idle",
	.attrs	= cpuidle_state_s2idle_attrs,
};

static void cpuidle_add_s2idle_attr_group(struct cpuidle_state_kobj *kobj)
{
	int ret;

	if (!kobj->state->enter_s2idle)
		return;

	ret = sysfs_create_group(&kobj->kobj, &cpuidle_state_s2idle_group);
	if (ret)
		pr_debug("%s: sysfs attribute group not created\n", __func__);
}

static void cpuidle_remove_s2idle_attr_group(struct cpuidle_state_kobj *kobj)
{
	if (kobj->state->enter_s2idle)
		sysfs_remove_group(&kobj->kobj, &cpuidle_state_s2idle_group);
}
#else
static inline void cpuidle_add_s2idle_attr_group(struct cpuidle_state_kobj *kobj) { }
static inline void cpuidle_remove_s2idle_attr_group(struct cpuidle_state_kobj *kobj) { }
#endif /* CONFIG_SUSPEND */

#define kobj_to_state_obj(k) container_of(k, struct cpuidle_state_kobj, kobj)
#define kobj_to_state(k) (kobj_to_state_obj(k)->state)
#define kobj_to_state_usage(k) (kobj_to_state_obj(k)->state_usage)
#define kobj_to_device(k) (kobj_to_state_obj(k)->device)
#define attr_to_stateattr(a) container_of(a, struct cpuidle_state_attr, attr)

static ssize_t cpuidle_state_show(struct kobject *kobj, struct attribute *attr,
				  char * buf)
{
	int ret = -EIO;
	struct cpuidle_state *state = kobj_to_state(kobj);
	struct cpuidle_state_usage *state_usage = kobj_to_state_usage(kobj);
	struct cpuidle_state_attr * cattr = attr_to_stateattr(attr);

	if (cattr->show)
		ret = cattr->show(state, state_usage, buf);

	return ret;
}

static ssize_t cpuidle_state_store(struct kobject *kobj, struct attribute *attr,
				   const char *buf, size_t size)
{
	int ret = -EIO;
	struct cpuidle_state *state = kobj_to_state(kobj);
	struct cpuidle_state_usage *state_usage = kobj_to_state_usage(kobj);
	struct cpuidle_state_attr *cattr = attr_to_stateattr(attr);
	struct cpuidle_device *dev = kobj_to_device(kobj);

	if (cattr->store)
		ret = cattr->store(state, state_usage, buf, size);

	/* reset poll time cache */
	dev->poll_limit_ns = 0;

	return ret;
}

static const struct sysfs_ops cpuidle_state_sysfs_ops = {
	.show = cpuidle_state_show,
	.store = cpuidle_state_store,
};

static void cpuidle_state_sysfs_release(struct kobject *kobj)
{
	struct cpuidle_state_kobj *state_obj = kobj_to_state_obj(kobj);

	complete(&state_obj->kobj_unregister);
}

static struct kobj_type ktype_state_cpuidle = {
	.sysfs_ops = &cpuidle_state_sysfs_ops,
	.default_attrs = cpuidle_state_default_attrs,
	.release = cpuidle_state_sysfs_release,
};

static inline void cpuidle_free_state_kobj(struct cpuidle_device *device, int i)
{
	cpuidle_remove_s2idle_attr_group(device->kobjs[i]);
	kobject_put(&device->kobjs[i]->kobj);
	wait_for_completion(&device->kobjs[i]->kobj_unregister);
	kfree(device->kobjs[i]);
	device->kobjs[i] = NULL;
}

/**
 * cpuidle_add_state_sysfs - adds cpuidle states sysfs attributes
 * @device: the target device
 */
static int cpuidle_add_state_sysfs(struct cpuidle_device *device)
{
	int i, ret = -ENOMEM;
	struct cpuidle_state_kobj *kobj;
	struct cpuidle_device_kobj *kdev = device->kobj_dev;
	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(device);

	/* state statistics */
	for (i = 0; i < drv->state_count; i++) {
		kobj = kzalloc(sizeof(struct cpuidle_state_kobj), GFP_KERNEL);
		if (!kobj) {
			ret = -ENOMEM;
			goto error_state;
		}
		kobj->state = &drv->states[i];
		kobj->state_usage = &device->states_usage[i];
		kobj->device = device;
		init_completion(&kobj->kobj_unregister);

		ret = kobject_init_and_add(&kobj->kobj, &ktype_state_cpuidle,
					   &kdev->kobj, "state%d", i);
		if (ret) {
			kfree(kobj);
			goto error_state;
		}
		cpuidle_add_s2idle_attr_group(kobj);
		kobject_uevent(&kobj->kobj, KOBJ_ADD);
		device->kobjs[i] = kobj;
	}

	return 0;

error_state:
	for (i = i - 1; i >= 0; i--)
		cpuidle_free_state_kobj(device, i);
	return ret;
}

/**
 * cpuidle_remove_driver_sysfs - removes the cpuidle states sysfs attributes
 * @device: the target device
 */
static void cpuidle_remove_state_sysfs(struct cpuidle_device *device)
{
	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(device);
	int i;

	for (i = 0; i < drv->state_count; i++)
		cpuidle_free_state_kobj(device, i);
}

#ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS
#define kobj_to_driver_kobj(k) container_of(k, struct cpuidle_driver_kobj, kobj)
#define attr_to_driver_attr(a) container_of(a, struct cpuidle_driver_attr, attr)

#define define_one_driver_ro(_name, show)                       \
	static struct cpuidle_driver_attr attr_driver_##_name = \
		__ATTR(_name, 0444, show, NULL)

struct cpuidle_driver_kobj {
	struct cpuidle_driver *drv;
	struct completion kobj_unregister;
	struct kobject kobj;
};

struct cpuidle_driver_attr {
	struct attribute attr;
	ssize_t (*show)(struct cpuidle_driver *, char *);
	ssize_t (*store)(struct cpuidle_driver *, const char *, size_t);
};

static ssize_t show_driver_name(struct cpuidle_driver *drv, char *buf)
{
	ssize_t ret;

	spin_lock(&cpuidle_driver_lock);
	ret = sprintf(buf, "%s\n", drv ? drv->name : "none");
	spin_unlock(&cpuidle_driver_lock);

	return ret;
}

static void cpuidle_driver_sysfs_release(struct kobject *kobj)
{
	struct cpuidle_driver_kobj *driver_kobj = kobj_to_driver_kobj(kobj);
	complete(&driver_kobj->kobj_unregister);
}

static ssize_t cpuidle_driver_show(struct kobject *kobj, struct attribute *attr,
				   char *buf)
{
	int ret = -EIO;
	struct cpuidle_driver_kobj *driver_kobj = kobj_to_driver_kobj(kobj);
	struct cpuidle_driver_attr *dattr = attr_to_driver_attr(attr);

	if (dattr->show)
		ret = dattr->show(driver_kobj->drv, buf);

	return ret;
}

static ssize_t cpuidle_driver_store(struct kobject *kobj, struct attribute *attr,
				    const char *buf, size_t size)
{
	int ret = -EIO;
	struct cpuidle_driver_kobj *driver_kobj = kobj_to_driver_kobj(kobj);
	struct cpuidle_driver_attr *dattr = attr_to_driver_attr(attr);

	if (dattr->store)
		ret = dattr->store(driver_kobj->drv, buf, size);

	return ret;
}

define_one_driver_ro(name, show_driver_name);

static const struct sysfs_ops cpuidle_driver_sysfs_ops = {
	.show = cpuidle_driver_show,
	.store = cpuidle_driver_store,
};

static struct attribute *cpuidle_driver_default_attrs[] = {
	&attr_driver_name.attr,
	NULL
};

static struct kobj_type ktype_driver_cpuidle = {
	.sysfs_ops = &cpuidle_driver_sysfs_ops,
	.default_attrs = cpuidle_driver_default_attrs,
	.release = cpuidle_driver_sysfs_release,
};

/**
 * cpuidle_add_driver_sysfs - adds the driver name sysfs attribute
 * @dev: the target device
 */
static int cpuidle_add_driver_sysfs(struct cpuidle_device *dev)
{
	struct cpuidle_driver_kobj *kdrv;
	struct cpuidle_device_kobj *kdev = dev->kobj_dev;
	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
	int ret;

	kdrv = kzalloc(sizeof(*kdrv), GFP_KERNEL);
	if (!kdrv)
		return -ENOMEM;

	kdrv->drv = drv;
	init_completion(&kdrv->kobj_unregister);

	ret = kobject_init_and_add(&kdrv->kobj, &ktype_driver_cpuidle,
				   &kdev->kobj, "driver");
	if (ret) {
		kfree(kdrv);
		return ret;
	}

	kobject_uevent(&kdrv->kobj, KOBJ_ADD);
	dev->kobj_driver = kdrv;

	return ret;
}

/**
 * cpuidle_remove_driver_sysfs - removes the driver name sysfs attribute
 * @dev: the target device
 */
static void cpuidle_remove_driver_sysfs(struct cpuidle_device *dev)
{
	struct cpuidle_driver_kobj *kdrv = dev->kobj_driver;
	kobject_put(&kdrv->kobj);
	wait_for_completion(&kdrv->kobj_unregister);
	kfree(kdrv);
}
#else
static inline int cpuidle_add_driver_sysfs(struct cpuidle_device *dev)
{
	return 0;
}

static inline void cpuidle_remove_driver_sysfs(struct cpuidle_device *dev)
{
	;
}
#endif

/**
 * cpuidle_add_device_sysfs - adds device specific sysfs attributes
 * @device: the target device
 */
int cpuidle_add_device_sysfs(struct cpuidle_device *device)
{
	int ret;

	ret = cpuidle_add_state_sysfs(device);
	if (ret)
		return ret;

	ret = cpuidle_add_driver_sysfs(device);
	if (ret)
		cpuidle_remove_state_sysfs(device);
	return ret;
}

/**
 * cpuidle_remove_device_sysfs : removes device specific sysfs attributes
 * @device : the target device
 */
void cpuidle_remove_device_sysfs(struct cpuidle_device *device)
{
	cpuidle_remove_driver_sysfs(device);
	cpuidle_remove_state_sysfs(device);
}

/**
 * cpuidle_add_sysfs - creates a sysfs instance for the target device
 * @dev: the target device
 */
int cpuidle_add_sysfs(struct cpuidle_device *dev)
{
	struct cpuidle_device_kobj *kdev;
	struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu);
	int error;

	/*
	 * Return if cpu_device is not setup for this CPU.
	 *
	 * This could happen if the arch did not set up cpu_device
	 * since this CPU is not in cpu_present mask and the
	 * driver did not send a correct CPU mask during registration.
	 * Without this check we would end up passing bogus
	 * value for &cpu_dev->kobj in kobject_init_and_add()
	 */
	if (!cpu_dev)
		return -ENODEV;

	kdev = kzalloc(sizeof(*kdev), GFP_KERNEL);
	if (!kdev)
		return -ENOMEM;
	kdev->dev = dev;
	dev->kobj_dev = kdev;

	init_completion(&kdev->kobj_unregister);

	error = kobject_init_and_add(&kdev->kobj, &ktype_cpuidle, &cpu_dev->kobj,
				   "cpuidle");
	if (error) {
		kfree(kdev);
		return error;
	}

	kobject_uevent(&kdev->kobj, KOBJ_ADD);

	return 0;
}

/**
 * cpuidle_remove_sysfs - deletes a sysfs instance on the target device
 * @dev: the target device
 */
void cpuidle_remove_sysfs(struct cpuidle_device *dev)
{
	struct cpuidle_device_kobj *kdev = dev->kobj_dev;

	kobject_put(&kdev->kobj);
	wait_for_completion(&kdev->kobj_unregister);
	kfree(kdev);
}