xref: /openbmc/linux/drivers/base/core.c (revision b6dcefde)
1 /*
2  * drivers/base/core.c - core driver model code (device registration, etc)
3  *
4  * Copyright (c) 2002-3 Patrick Mochel
5  * Copyright (c) 2002-3 Open Source Development Labs
6  * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
7  * Copyright (c) 2006 Novell, Inc.
8  *
9  * This file is released under the GPLv2
10  *
11  */
12 
13 #include <linux/device.h>
14 #include <linux/err.h>
15 #include <linux/init.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <linux/string.h>
19 #include <linux/kdev_t.h>
20 #include <linux/notifier.h>
21 #include <linux/genhd.h>
22 #include <linux/kallsyms.h>
23 #include <linux/semaphore.h>
24 #include <linux/mutex.h>
25 #include <linux/async.h>
26 
27 #include "base.h"
28 #include "power/power.h"
29 
30 int (*platform_notify)(struct device *dev) = NULL;
31 int (*platform_notify_remove)(struct device *dev) = NULL;
32 static struct kobject *dev_kobj;
33 struct kobject *sysfs_dev_char_kobj;
34 struct kobject *sysfs_dev_block_kobj;
35 
36 #ifdef CONFIG_BLOCK
37 static inline int device_is_not_partition(struct device *dev)
38 {
39 	return !(dev->type == &part_type);
40 }
41 #else
42 static inline int device_is_not_partition(struct device *dev)
43 {
44 	return 1;
45 }
46 #endif
47 
48 /**
49  * dev_driver_string - Return a device's driver name, if at all possible
50  * @dev: struct device to get the name of
51  *
52  * Will return the device's driver's name if it is bound to a device.  If
53  * the device is not bound to a device, it will return the name of the bus
54  * it is attached to.  If it is not attached to a bus either, an empty
55  * string will be returned.
56  */
57 const char *dev_driver_string(const struct device *dev)
58 {
59 	struct device_driver *drv;
60 
61 	/* dev->driver can change to NULL underneath us because of unbinding,
62 	 * so be careful about accessing it.  dev->bus and dev->class should
63 	 * never change once they are set, so they don't need special care.
64 	 */
65 	drv = ACCESS_ONCE(dev->driver);
66 	return drv ? drv->name :
67 			(dev->bus ? dev->bus->name :
68 			(dev->class ? dev->class->name : ""));
69 }
70 EXPORT_SYMBOL(dev_driver_string);
71 
72 #define to_dev(obj) container_of(obj, struct device, kobj)
73 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
74 
75 static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
76 			     char *buf)
77 {
78 	struct device_attribute *dev_attr = to_dev_attr(attr);
79 	struct device *dev = to_dev(kobj);
80 	ssize_t ret = -EIO;
81 
82 	if (dev_attr->show)
83 		ret = dev_attr->show(dev, dev_attr, buf);
84 	if (ret >= (ssize_t)PAGE_SIZE) {
85 		print_symbol("dev_attr_show: %s returned bad count\n",
86 				(unsigned long)dev_attr->show);
87 	}
88 	return ret;
89 }
90 
91 static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
92 			      const char *buf, size_t count)
93 {
94 	struct device_attribute *dev_attr = to_dev_attr(attr);
95 	struct device *dev = to_dev(kobj);
96 	ssize_t ret = -EIO;
97 
98 	if (dev_attr->store)
99 		ret = dev_attr->store(dev, dev_attr, buf, count);
100 	return ret;
101 }
102 
103 static struct sysfs_ops dev_sysfs_ops = {
104 	.show	= dev_attr_show,
105 	.store	= dev_attr_store,
106 };
107 
108 
109 /**
110  *	device_release - free device structure.
111  *	@kobj:	device's kobject.
112  *
113  *	This is called once the reference count for the object
114  *	reaches 0. We forward the call to the device's release
115  *	method, which should handle actually freeing the structure.
116  */
117 static void device_release(struct kobject *kobj)
118 {
119 	struct device *dev = to_dev(kobj);
120 	struct device_private *p = dev->p;
121 
122 	if (dev->release)
123 		dev->release(dev);
124 	else if (dev->type && dev->type->release)
125 		dev->type->release(dev);
126 	else if (dev->class && dev->class->dev_release)
127 		dev->class->dev_release(dev);
128 	else
129 		WARN(1, KERN_ERR "Device '%s' does not have a release() "
130 			"function, it is broken and must be fixed.\n",
131 			dev_name(dev));
132 	kfree(p);
133 }
134 
135 static struct kobj_type device_ktype = {
136 	.release	= device_release,
137 	.sysfs_ops	= &dev_sysfs_ops,
138 };
139 
140 
141 static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
142 {
143 	struct kobj_type *ktype = get_ktype(kobj);
144 
145 	if (ktype == &device_ktype) {
146 		struct device *dev = to_dev(kobj);
147 		if (dev->bus)
148 			return 1;
149 		if (dev->class)
150 			return 1;
151 	}
152 	return 0;
153 }
154 
155 static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
156 {
157 	struct device *dev = to_dev(kobj);
158 
159 	if (dev->bus)
160 		return dev->bus->name;
161 	if (dev->class)
162 		return dev->class->name;
163 	return NULL;
164 }
165 
166 static int dev_uevent(struct kset *kset, struct kobject *kobj,
167 		      struct kobj_uevent_env *env)
168 {
169 	struct device *dev = to_dev(kobj);
170 	int retval = 0;
171 
172 	/* add device node properties if present */
173 	if (MAJOR(dev->devt)) {
174 		const char *tmp;
175 		const char *name;
176 		mode_t mode = 0;
177 
178 		add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
179 		add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
180 		name = device_get_devnode(dev, &mode, &tmp);
181 		if (name) {
182 			add_uevent_var(env, "DEVNAME=%s", name);
183 			kfree(tmp);
184 			if (mode)
185 				add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
186 		}
187 	}
188 
189 	if (dev->type && dev->type->name)
190 		add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
191 
192 	if (dev->driver)
193 		add_uevent_var(env, "DRIVER=%s", dev->driver->name);
194 
195 #ifdef CONFIG_SYSFS_DEPRECATED
196 	if (dev->class) {
197 		struct device *parent = dev->parent;
198 
199 		/* find first bus device in parent chain */
200 		while (parent && !parent->bus)
201 			parent = parent->parent;
202 		if (parent && parent->bus) {
203 			const char *path;
204 
205 			path = kobject_get_path(&parent->kobj, GFP_KERNEL);
206 			if (path) {
207 				add_uevent_var(env, "PHYSDEVPATH=%s", path);
208 				kfree(path);
209 			}
210 
211 			add_uevent_var(env, "PHYSDEVBUS=%s", parent->bus->name);
212 
213 			if (parent->driver)
214 				add_uevent_var(env, "PHYSDEVDRIVER=%s",
215 					       parent->driver->name);
216 		}
217 	} else if (dev->bus) {
218 		add_uevent_var(env, "PHYSDEVBUS=%s", dev->bus->name);
219 
220 		if (dev->driver)
221 			add_uevent_var(env, "PHYSDEVDRIVER=%s",
222 				       dev->driver->name);
223 	}
224 #endif
225 
226 	/* have the bus specific function add its stuff */
227 	if (dev->bus && dev->bus->uevent) {
228 		retval = dev->bus->uevent(dev, env);
229 		if (retval)
230 			pr_debug("device: '%s': %s: bus uevent() returned %d\n",
231 				 dev_name(dev), __func__, retval);
232 	}
233 
234 	/* have the class specific function add its stuff */
235 	if (dev->class && dev->class->dev_uevent) {
236 		retval = dev->class->dev_uevent(dev, env);
237 		if (retval)
238 			pr_debug("device: '%s': %s: class uevent() "
239 				 "returned %d\n", dev_name(dev),
240 				 __func__, retval);
241 	}
242 
243 	/* have the device type specific fuction add its stuff */
244 	if (dev->type && dev->type->uevent) {
245 		retval = dev->type->uevent(dev, env);
246 		if (retval)
247 			pr_debug("device: '%s': %s: dev_type uevent() "
248 				 "returned %d\n", dev_name(dev),
249 				 __func__, retval);
250 	}
251 
252 	return retval;
253 }
254 
255 static struct kset_uevent_ops device_uevent_ops = {
256 	.filter =	dev_uevent_filter,
257 	.name =		dev_uevent_name,
258 	.uevent =	dev_uevent,
259 };
260 
261 static ssize_t show_uevent(struct device *dev, struct device_attribute *attr,
262 			   char *buf)
263 {
264 	struct kobject *top_kobj;
265 	struct kset *kset;
266 	struct kobj_uevent_env *env = NULL;
267 	int i;
268 	size_t count = 0;
269 	int retval;
270 
271 	/* search the kset, the device belongs to */
272 	top_kobj = &dev->kobj;
273 	while (!top_kobj->kset && top_kobj->parent)
274 		top_kobj = top_kobj->parent;
275 	if (!top_kobj->kset)
276 		goto out;
277 
278 	kset = top_kobj->kset;
279 	if (!kset->uevent_ops || !kset->uevent_ops->uevent)
280 		goto out;
281 
282 	/* respect filter */
283 	if (kset->uevent_ops && kset->uevent_ops->filter)
284 		if (!kset->uevent_ops->filter(kset, &dev->kobj))
285 			goto out;
286 
287 	env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
288 	if (!env)
289 		return -ENOMEM;
290 
291 	/* let the kset specific function add its keys */
292 	retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
293 	if (retval)
294 		goto out;
295 
296 	/* copy keys to file */
297 	for (i = 0; i < env->envp_idx; i++)
298 		count += sprintf(&buf[count], "%s\n", env->envp[i]);
299 out:
300 	kfree(env);
301 	return count;
302 }
303 
304 static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
305 			    const char *buf, size_t count)
306 {
307 	enum kobject_action action;
308 
309 	if (kobject_action_type(buf, count, &action) == 0) {
310 		kobject_uevent(&dev->kobj, action);
311 		goto out;
312 	}
313 
314 	dev_err(dev, "uevent: unsupported action-string; this will "
315 		     "be ignored in a future kernel version\n");
316 	kobject_uevent(&dev->kobj, KOBJ_ADD);
317 out:
318 	return count;
319 }
320 
321 static struct device_attribute uevent_attr =
322 	__ATTR(uevent, S_IRUGO | S_IWUSR, show_uevent, store_uevent);
323 
324 static int device_add_attributes(struct device *dev,
325 				 struct device_attribute *attrs)
326 {
327 	int error = 0;
328 	int i;
329 
330 	if (attrs) {
331 		for (i = 0; attr_name(attrs[i]); i++) {
332 			error = device_create_file(dev, &attrs[i]);
333 			if (error)
334 				break;
335 		}
336 		if (error)
337 			while (--i >= 0)
338 				device_remove_file(dev, &attrs[i]);
339 	}
340 	return error;
341 }
342 
343 static void device_remove_attributes(struct device *dev,
344 				     struct device_attribute *attrs)
345 {
346 	int i;
347 
348 	if (attrs)
349 		for (i = 0; attr_name(attrs[i]); i++)
350 			device_remove_file(dev, &attrs[i]);
351 }
352 
353 static int device_add_groups(struct device *dev,
354 			     const struct attribute_group **groups)
355 {
356 	int error = 0;
357 	int i;
358 
359 	if (groups) {
360 		for (i = 0; groups[i]; i++) {
361 			error = sysfs_create_group(&dev->kobj, groups[i]);
362 			if (error) {
363 				while (--i >= 0)
364 					sysfs_remove_group(&dev->kobj,
365 							   groups[i]);
366 				break;
367 			}
368 		}
369 	}
370 	return error;
371 }
372 
373 static void device_remove_groups(struct device *dev,
374 				 const struct attribute_group **groups)
375 {
376 	int i;
377 
378 	if (groups)
379 		for (i = 0; groups[i]; i++)
380 			sysfs_remove_group(&dev->kobj, groups[i]);
381 }
382 
383 static int device_add_attrs(struct device *dev)
384 {
385 	struct class *class = dev->class;
386 	struct device_type *type = dev->type;
387 	int error;
388 
389 	if (class) {
390 		error = device_add_attributes(dev, class->dev_attrs);
391 		if (error)
392 			return error;
393 	}
394 
395 	if (type) {
396 		error = device_add_groups(dev, type->groups);
397 		if (error)
398 			goto err_remove_class_attrs;
399 	}
400 
401 	error = device_add_groups(dev, dev->groups);
402 	if (error)
403 		goto err_remove_type_groups;
404 
405 	return 0;
406 
407  err_remove_type_groups:
408 	if (type)
409 		device_remove_groups(dev, type->groups);
410  err_remove_class_attrs:
411 	if (class)
412 		device_remove_attributes(dev, class->dev_attrs);
413 
414 	return error;
415 }
416 
417 static void device_remove_attrs(struct device *dev)
418 {
419 	struct class *class = dev->class;
420 	struct device_type *type = dev->type;
421 
422 	device_remove_groups(dev, dev->groups);
423 
424 	if (type)
425 		device_remove_groups(dev, type->groups);
426 
427 	if (class)
428 		device_remove_attributes(dev, class->dev_attrs);
429 }
430 
431 
432 static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
433 			char *buf)
434 {
435 	return print_dev_t(buf, dev->devt);
436 }
437 
438 static struct device_attribute devt_attr =
439 	__ATTR(dev, S_IRUGO, show_dev, NULL);
440 
441 /* kset to create /sys/devices/  */
442 struct kset *devices_kset;
443 
444 /**
445  * device_create_file - create sysfs attribute file for device.
446  * @dev: device.
447  * @attr: device attribute descriptor.
448  */
449 int device_create_file(struct device *dev,
450 		       const struct device_attribute *attr)
451 {
452 	int error = 0;
453 	if (dev)
454 		error = sysfs_create_file(&dev->kobj, &attr->attr);
455 	return error;
456 }
457 
458 /**
459  * device_remove_file - remove sysfs attribute file.
460  * @dev: device.
461  * @attr: device attribute descriptor.
462  */
463 void device_remove_file(struct device *dev,
464 			const struct device_attribute *attr)
465 {
466 	if (dev)
467 		sysfs_remove_file(&dev->kobj, &attr->attr);
468 }
469 
470 /**
471  * device_create_bin_file - create sysfs binary attribute file for device.
472  * @dev: device.
473  * @attr: device binary attribute descriptor.
474  */
475 int device_create_bin_file(struct device *dev,
476 			   const struct bin_attribute *attr)
477 {
478 	int error = -EINVAL;
479 	if (dev)
480 		error = sysfs_create_bin_file(&dev->kobj, attr);
481 	return error;
482 }
483 EXPORT_SYMBOL_GPL(device_create_bin_file);
484 
485 /**
486  * device_remove_bin_file - remove sysfs binary attribute file
487  * @dev: device.
488  * @attr: device binary attribute descriptor.
489  */
490 void device_remove_bin_file(struct device *dev,
491 			    const struct bin_attribute *attr)
492 {
493 	if (dev)
494 		sysfs_remove_bin_file(&dev->kobj, attr);
495 }
496 EXPORT_SYMBOL_GPL(device_remove_bin_file);
497 
498 /**
499  * device_schedule_callback_owner - helper to schedule a callback for a device
500  * @dev: device.
501  * @func: callback function to invoke later.
502  * @owner: module owning the callback routine
503  *
504  * Attribute methods must not unregister themselves or their parent device
505  * (which would amount to the same thing).  Attempts to do so will deadlock,
506  * since unregistration is mutually exclusive with driver callbacks.
507  *
508  * Instead methods can call this routine, which will attempt to allocate
509  * and schedule a workqueue request to call back @func with @dev as its
510  * argument in the workqueue's process context.  @dev will be pinned until
511  * @func returns.
512  *
513  * This routine is usually called via the inline device_schedule_callback(),
514  * which automatically sets @owner to THIS_MODULE.
515  *
516  * Returns 0 if the request was submitted, -ENOMEM if storage could not
517  * be allocated, -ENODEV if a reference to @owner isn't available.
518  *
519  * NOTE: This routine won't work if CONFIG_SYSFS isn't set!  It uses an
520  * underlying sysfs routine (since it is intended for use by attribute
521  * methods), and if sysfs isn't available you'll get nothing but -ENOSYS.
522  */
523 int device_schedule_callback_owner(struct device *dev,
524 		void (*func)(struct device *), struct module *owner)
525 {
526 	return sysfs_schedule_callback(&dev->kobj,
527 			(void (*)(void *)) func, dev, owner);
528 }
529 EXPORT_SYMBOL_GPL(device_schedule_callback_owner);
530 
531 static void klist_children_get(struct klist_node *n)
532 {
533 	struct device_private *p = to_device_private_parent(n);
534 	struct device *dev = p->device;
535 
536 	get_device(dev);
537 }
538 
539 static void klist_children_put(struct klist_node *n)
540 {
541 	struct device_private *p = to_device_private_parent(n);
542 	struct device *dev = p->device;
543 
544 	put_device(dev);
545 }
546 
547 /**
548  * device_initialize - init device structure.
549  * @dev: device.
550  *
551  * This prepares the device for use by other layers by initializing
552  * its fields.
553  * It is the first half of device_register(), if called by
554  * that function, though it can also be called separately, so one
555  * may use @dev's fields. In particular, get_device()/put_device()
556  * may be used for reference counting of @dev after calling this
557  * function.
558  *
559  * NOTE: Use put_device() to give up your reference instead of freeing
560  * @dev directly once you have called this function.
561  */
562 void device_initialize(struct device *dev)
563 {
564 	dev->kobj.kset = devices_kset;
565 	kobject_init(&dev->kobj, &device_ktype);
566 	INIT_LIST_HEAD(&dev->dma_pools);
567 	init_MUTEX(&dev->sem);
568 	spin_lock_init(&dev->devres_lock);
569 	INIT_LIST_HEAD(&dev->devres_head);
570 	device_init_wakeup(dev, 0);
571 	device_pm_init(dev);
572 	set_dev_node(dev, -1);
573 }
574 
575 #ifdef CONFIG_SYSFS_DEPRECATED
576 static struct kobject *get_device_parent(struct device *dev,
577 					 struct device *parent)
578 {
579 	/* class devices without a parent live in /sys/class/<classname>/ */
580 	if (dev->class && (!parent || parent->class != dev->class))
581 		return &dev->class->p->class_subsys.kobj;
582 	/* all other devices keep their parent */
583 	else if (parent)
584 		return &parent->kobj;
585 
586 	return NULL;
587 }
588 
589 static inline void cleanup_device_parent(struct device *dev) {}
590 static inline void cleanup_glue_dir(struct device *dev,
591 				    struct kobject *glue_dir) {}
592 #else
593 static struct kobject *virtual_device_parent(struct device *dev)
594 {
595 	static struct kobject *virtual_dir = NULL;
596 
597 	if (!virtual_dir)
598 		virtual_dir = kobject_create_and_add("virtual",
599 						     &devices_kset->kobj);
600 
601 	return virtual_dir;
602 }
603 
604 static struct kobject *get_device_parent(struct device *dev,
605 					 struct device *parent)
606 {
607 	int retval;
608 
609 	if (dev->class) {
610 		struct kobject *kobj = NULL;
611 		struct kobject *parent_kobj;
612 		struct kobject *k;
613 
614 		/*
615 		 * If we have no parent, we live in "virtual".
616 		 * Class-devices with a non class-device as parent, live
617 		 * in a "glue" directory to prevent namespace collisions.
618 		 */
619 		if (parent == NULL)
620 			parent_kobj = virtual_device_parent(dev);
621 		else if (parent->class)
622 			return &parent->kobj;
623 		else
624 			parent_kobj = &parent->kobj;
625 
626 		/* find our class-directory at the parent and reference it */
627 		spin_lock(&dev->class->p->class_dirs.list_lock);
628 		list_for_each_entry(k, &dev->class->p->class_dirs.list, entry)
629 			if (k->parent == parent_kobj) {
630 				kobj = kobject_get(k);
631 				break;
632 			}
633 		spin_unlock(&dev->class->p->class_dirs.list_lock);
634 		if (kobj)
635 			return kobj;
636 
637 		/* or create a new class-directory at the parent device */
638 		k = kobject_create();
639 		if (!k)
640 			return NULL;
641 		k->kset = &dev->class->p->class_dirs;
642 		retval = kobject_add(k, parent_kobj, "%s", dev->class->name);
643 		if (retval < 0) {
644 			kobject_put(k);
645 			return NULL;
646 		}
647 		/* do not emit an uevent for this simple "glue" directory */
648 		return k;
649 	}
650 
651 	if (parent)
652 		return &parent->kobj;
653 	return NULL;
654 }
655 
656 static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
657 {
658 	/* see if we live in a "glue" directory */
659 	if (!glue_dir || !dev->class ||
660 	    glue_dir->kset != &dev->class->p->class_dirs)
661 		return;
662 
663 	kobject_put(glue_dir);
664 }
665 
666 static void cleanup_device_parent(struct device *dev)
667 {
668 	cleanup_glue_dir(dev, dev->kobj.parent);
669 }
670 #endif
671 
672 static void setup_parent(struct device *dev, struct device *parent)
673 {
674 	struct kobject *kobj;
675 	kobj = get_device_parent(dev, parent);
676 	if (kobj)
677 		dev->kobj.parent = kobj;
678 }
679 
680 static int device_add_class_symlinks(struct device *dev)
681 {
682 	int error;
683 
684 	if (!dev->class)
685 		return 0;
686 
687 	error = sysfs_create_link(&dev->kobj,
688 				  &dev->class->p->class_subsys.kobj,
689 				  "subsystem");
690 	if (error)
691 		goto out;
692 
693 #ifdef CONFIG_SYSFS_DEPRECATED
694 	/* stacked class devices need a symlink in the class directory */
695 	if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
696 	    device_is_not_partition(dev)) {
697 		error = sysfs_create_link(&dev->class->p->class_subsys.kobj,
698 					  &dev->kobj, dev_name(dev));
699 		if (error)
700 			goto out_subsys;
701 	}
702 
703 	if (dev->parent && device_is_not_partition(dev)) {
704 		struct device *parent = dev->parent;
705 		char *class_name;
706 
707 		/*
708 		 * stacked class devices have the 'device' link
709 		 * pointing to the bus device instead of the parent
710 		 */
711 		while (parent->class && !parent->bus && parent->parent)
712 			parent = parent->parent;
713 
714 		error = sysfs_create_link(&dev->kobj,
715 					  &parent->kobj,
716 					  "device");
717 		if (error)
718 			goto out_busid;
719 
720 		class_name = make_class_name(dev->class->name,
721 						&dev->kobj);
722 		if (class_name)
723 			error = sysfs_create_link(&dev->parent->kobj,
724 						&dev->kobj, class_name);
725 		kfree(class_name);
726 		if (error)
727 			goto out_device;
728 	}
729 	return 0;
730 
731 out_device:
732 	if (dev->parent && device_is_not_partition(dev))
733 		sysfs_remove_link(&dev->kobj, "device");
734 out_busid:
735 	if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
736 	    device_is_not_partition(dev))
737 		sysfs_remove_link(&dev->class->p->class_subsys.kobj,
738 				  dev_name(dev));
739 #else
740 	/* link in the class directory pointing to the device */
741 	error = sysfs_create_link(&dev->class->p->class_subsys.kobj,
742 				  &dev->kobj, dev_name(dev));
743 	if (error)
744 		goto out_subsys;
745 
746 	if (dev->parent && device_is_not_partition(dev)) {
747 		error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
748 					  "device");
749 		if (error)
750 			goto out_busid;
751 	}
752 	return 0;
753 
754 out_busid:
755 	sysfs_remove_link(&dev->class->p->class_subsys.kobj, dev_name(dev));
756 #endif
757 
758 out_subsys:
759 	sysfs_remove_link(&dev->kobj, "subsystem");
760 out:
761 	return error;
762 }
763 
764 static void device_remove_class_symlinks(struct device *dev)
765 {
766 	if (!dev->class)
767 		return;
768 
769 #ifdef CONFIG_SYSFS_DEPRECATED
770 	if (dev->parent && device_is_not_partition(dev)) {
771 		char *class_name;
772 
773 		class_name = make_class_name(dev->class->name, &dev->kobj);
774 		if (class_name) {
775 			sysfs_remove_link(&dev->parent->kobj, class_name);
776 			kfree(class_name);
777 		}
778 		sysfs_remove_link(&dev->kobj, "device");
779 	}
780 
781 	if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
782 	    device_is_not_partition(dev))
783 		sysfs_remove_link(&dev->class->p->class_subsys.kobj,
784 				  dev_name(dev));
785 #else
786 	if (dev->parent && device_is_not_partition(dev))
787 		sysfs_remove_link(&dev->kobj, "device");
788 
789 	sysfs_remove_link(&dev->class->p->class_subsys.kobj, dev_name(dev));
790 #endif
791 
792 	sysfs_remove_link(&dev->kobj, "subsystem");
793 }
794 
795 /**
796  * dev_set_name - set a device name
797  * @dev: device
798  * @fmt: format string for the device's name
799  */
800 int dev_set_name(struct device *dev, const char *fmt, ...)
801 {
802 	va_list vargs;
803 	int err;
804 
805 	va_start(vargs, fmt);
806 	err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
807 	va_end(vargs);
808 	return err;
809 }
810 EXPORT_SYMBOL_GPL(dev_set_name);
811 
812 /**
813  * device_to_dev_kobj - select a /sys/dev/ directory for the device
814  * @dev: device
815  *
816  * By default we select char/ for new entries.  Setting class->dev_obj
817  * to NULL prevents an entry from being created.  class->dev_kobj must
818  * be set (or cleared) before any devices are registered to the class
819  * otherwise device_create_sys_dev_entry() and
820  * device_remove_sys_dev_entry() will disagree about the the presence
821  * of the link.
822  */
823 static struct kobject *device_to_dev_kobj(struct device *dev)
824 {
825 	struct kobject *kobj;
826 
827 	if (dev->class)
828 		kobj = dev->class->dev_kobj;
829 	else
830 		kobj = sysfs_dev_char_kobj;
831 
832 	return kobj;
833 }
834 
835 static int device_create_sys_dev_entry(struct device *dev)
836 {
837 	struct kobject *kobj = device_to_dev_kobj(dev);
838 	int error = 0;
839 	char devt_str[15];
840 
841 	if (kobj) {
842 		format_dev_t(devt_str, dev->devt);
843 		error = sysfs_create_link(kobj, &dev->kobj, devt_str);
844 	}
845 
846 	return error;
847 }
848 
849 static void device_remove_sys_dev_entry(struct device *dev)
850 {
851 	struct kobject *kobj = device_to_dev_kobj(dev);
852 	char devt_str[15];
853 
854 	if (kobj) {
855 		format_dev_t(devt_str, dev->devt);
856 		sysfs_remove_link(kobj, devt_str);
857 	}
858 }
859 
860 int device_private_init(struct device *dev)
861 {
862 	dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
863 	if (!dev->p)
864 		return -ENOMEM;
865 	dev->p->device = dev;
866 	klist_init(&dev->p->klist_children, klist_children_get,
867 		   klist_children_put);
868 	return 0;
869 }
870 
871 /**
872  * device_add - add device to device hierarchy.
873  * @dev: device.
874  *
875  * This is part 2 of device_register(), though may be called
876  * separately _iff_ device_initialize() has been called separately.
877  *
878  * This adds @dev to the kobject hierarchy via kobject_add(), adds it
879  * to the global and sibling lists for the device, then
880  * adds it to the other relevant subsystems of the driver model.
881  *
882  * NOTE: _Never_ directly free @dev after calling this function, even
883  * if it returned an error! Always use put_device() to give up your
884  * reference instead.
885  */
886 int device_add(struct device *dev)
887 {
888 	struct device *parent = NULL;
889 	struct class_interface *class_intf;
890 	int error = -EINVAL;
891 
892 	dev = get_device(dev);
893 	if (!dev)
894 		goto done;
895 
896 	if (!dev->p) {
897 		error = device_private_init(dev);
898 		if (error)
899 			goto done;
900 	}
901 
902 	/*
903 	 * for statically allocated devices, which should all be converted
904 	 * some day, we need to initialize the name. We prevent reading back
905 	 * the name, and force the use of dev_name()
906 	 */
907 	if (dev->init_name) {
908 		dev_set_name(dev, "%s", dev->init_name);
909 		dev->init_name = NULL;
910 	}
911 
912 	if (!dev_name(dev)) {
913 		error = -EINVAL;
914 		goto name_error;
915 	}
916 
917 	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
918 
919 	parent = get_device(dev->parent);
920 	setup_parent(dev, parent);
921 
922 	/* use parent numa_node */
923 	if (parent)
924 		set_dev_node(dev, dev_to_node(parent));
925 
926 	/* first, register with generic layer. */
927 	/* we require the name to be set before, and pass NULL */
928 	error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
929 	if (error)
930 		goto Error;
931 
932 	/* notify platform of device entry */
933 	if (platform_notify)
934 		platform_notify(dev);
935 
936 	error = device_create_file(dev, &uevent_attr);
937 	if (error)
938 		goto attrError;
939 
940 	if (MAJOR(dev->devt)) {
941 		error = device_create_file(dev, &devt_attr);
942 		if (error)
943 			goto ueventattrError;
944 
945 		error = device_create_sys_dev_entry(dev);
946 		if (error)
947 			goto devtattrError;
948 
949 		devtmpfs_create_node(dev);
950 	}
951 
952 	error = device_add_class_symlinks(dev);
953 	if (error)
954 		goto SymlinkError;
955 	error = device_add_attrs(dev);
956 	if (error)
957 		goto AttrsError;
958 	error = bus_add_device(dev);
959 	if (error)
960 		goto BusError;
961 	error = dpm_sysfs_add(dev);
962 	if (error)
963 		goto DPMError;
964 	device_pm_add(dev);
965 
966 	/* Notify clients of device addition.  This call must come
967 	 * after dpm_sysf_add() and before kobject_uevent().
968 	 */
969 	if (dev->bus)
970 		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
971 					     BUS_NOTIFY_ADD_DEVICE, dev);
972 
973 	kobject_uevent(&dev->kobj, KOBJ_ADD);
974 	bus_probe_device(dev);
975 	if (parent)
976 		klist_add_tail(&dev->p->knode_parent,
977 			       &parent->p->klist_children);
978 
979 	if (dev->class) {
980 		mutex_lock(&dev->class->p->class_mutex);
981 		/* tie the class to the device */
982 		klist_add_tail(&dev->knode_class,
983 			       &dev->class->p->class_devices);
984 
985 		/* notify any interfaces that the device is here */
986 		list_for_each_entry(class_intf,
987 				    &dev->class->p->class_interfaces, node)
988 			if (class_intf->add_dev)
989 				class_intf->add_dev(dev, class_intf);
990 		mutex_unlock(&dev->class->p->class_mutex);
991 	}
992 done:
993 	put_device(dev);
994 	return error;
995  DPMError:
996 	bus_remove_device(dev);
997  BusError:
998 	device_remove_attrs(dev);
999  AttrsError:
1000 	device_remove_class_symlinks(dev);
1001  SymlinkError:
1002 	if (MAJOR(dev->devt))
1003 		devtmpfs_delete_node(dev);
1004 	if (MAJOR(dev->devt))
1005 		device_remove_sys_dev_entry(dev);
1006  devtattrError:
1007 	if (MAJOR(dev->devt))
1008 		device_remove_file(dev, &devt_attr);
1009  ueventattrError:
1010 	device_remove_file(dev, &uevent_attr);
1011  attrError:
1012 	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1013 	kobject_del(&dev->kobj);
1014  Error:
1015 	cleanup_device_parent(dev);
1016 	if (parent)
1017 		put_device(parent);
1018 name_error:
1019 	kfree(dev->p);
1020 	dev->p = NULL;
1021 	goto done;
1022 }
1023 
1024 /**
1025  * device_register - register a device with the system.
1026  * @dev: pointer to the device structure
1027  *
1028  * This happens in two clean steps - initialize the device
1029  * and add it to the system. The two steps can be called
1030  * separately, but this is the easiest and most common.
1031  * I.e. you should only call the two helpers separately if
1032  * have a clearly defined need to use and refcount the device
1033  * before it is added to the hierarchy.
1034  *
1035  * NOTE: _Never_ directly free @dev after calling this function, even
1036  * if it returned an error! Always use put_device() to give up the
1037  * reference initialized in this function instead.
1038  */
1039 int device_register(struct device *dev)
1040 {
1041 	device_initialize(dev);
1042 	return device_add(dev);
1043 }
1044 
1045 /**
1046  * get_device - increment reference count for device.
1047  * @dev: device.
1048  *
1049  * This simply forwards the call to kobject_get(), though
1050  * we do take care to provide for the case that we get a NULL
1051  * pointer passed in.
1052  */
1053 struct device *get_device(struct device *dev)
1054 {
1055 	return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
1056 }
1057 
1058 /**
1059  * put_device - decrement reference count.
1060  * @dev: device in question.
1061  */
1062 void put_device(struct device *dev)
1063 {
1064 	/* might_sleep(); */
1065 	if (dev)
1066 		kobject_put(&dev->kobj);
1067 }
1068 
1069 /**
1070  * device_del - delete device from system.
1071  * @dev: device.
1072  *
1073  * This is the first part of the device unregistration
1074  * sequence. This removes the device from the lists we control
1075  * from here, has it removed from the other driver model
1076  * subsystems it was added to in device_add(), and removes it
1077  * from the kobject hierarchy.
1078  *
1079  * NOTE: this should be called manually _iff_ device_add() was
1080  * also called manually.
1081  */
1082 void device_del(struct device *dev)
1083 {
1084 	struct device *parent = dev->parent;
1085 	struct class_interface *class_intf;
1086 
1087 	/* Notify clients of device removal.  This call must come
1088 	 * before dpm_sysfs_remove().
1089 	 */
1090 	if (dev->bus)
1091 		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1092 					     BUS_NOTIFY_DEL_DEVICE, dev);
1093 	device_pm_remove(dev);
1094 	dpm_sysfs_remove(dev);
1095 	if (parent)
1096 		klist_del(&dev->p->knode_parent);
1097 	if (MAJOR(dev->devt)) {
1098 		devtmpfs_delete_node(dev);
1099 		device_remove_sys_dev_entry(dev);
1100 		device_remove_file(dev, &devt_attr);
1101 	}
1102 	if (dev->class) {
1103 		device_remove_class_symlinks(dev);
1104 
1105 		mutex_lock(&dev->class->p->class_mutex);
1106 		/* notify any interfaces that the device is now gone */
1107 		list_for_each_entry(class_intf,
1108 				    &dev->class->p->class_interfaces, node)
1109 			if (class_intf->remove_dev)
1110 				class_intf->remove_dev(dev, class_intf);
1111 		/* remove the device from the class list */
1112 		klist_del(&dev->knode_class);
1113 		mutex_unlock(&dev->class->p->class_mutex);
1114 	}
1115 	device_remove_file(dev, &uevent_attr);
1116 	device_remove_attrs(dev);
1117 	bus_remove_device(dev);
1118 
1119 	/*
1120 	 * Some platform devices are driven without driver attached
1121 	 * and managed resources may have been acquired.  Make sure
1122 	 * all resources are released.
1123 	 */
1124 	devres_release_all(dev);
1125 
1126 	/* Notify the platform of the removal, in case they
1127 	 * need to do anything...
1128 	 */
1129 	if (platform_notify_remove)
1130 		platform_notify_remove(dev);
1131 	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1132 	cleanup_device_parent(dev);
1133 	kobject_del(&dev->kobj);
1134 	put_device(parent);
1135 }
1136 
1137 /**
1138  * device_unregister - unregister device from system.
1139  * @dev: device going away.
1140  *
1141  * We do this in two parts, like we do device_register(). First,
1142  * we remove it from all the subsystems with device_del(), then
1143  * we decrement the reference count via put_device(). If that
1144  * is the final reference count, the device will be cleaned up
1145  * via device_release() above. Otherwise, the structure will
1146  * stick around until the final reference to the device is dropped.
1147  */
1148 void device_unregister(struct device *dev)
1149 {
1150 	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1151 	device_del(dev);
1152 	put_device(dev);
1153 }
1154 
1155 static struct device *next_device(struct klist_iter *i)
1156 {
1157 	struct klist_node *n = klist_next(i);
1158 	struct device *dev = NULL;
1159 	struct device_private *p;
1160 
1161 	if (n) {
1162 		p = to_device_private_parent(n);
1163 		dev = p->device;
1164 	}
1165 	return dev;
1166 }
1167 
1168 /**
1169  * device_get_devnode - path of device node file
1170  * @dev: device
1171  * @mode: returned file access mode
1172  * @tmp: possibly allocated string
1173  *
1174  * Return the relative path of a possible device node.
1175  * Non-default names may need to allocate a memory to compose
1176  * a name. This memory is returned in tmp and needs to be
1177  * freed by the caller.
1178  */
1179 const char *device_get_devnode(struct device *dev,
1180 			       mode_t *mode, const char **tmp)
1181 {
1182 	char *s;
1183 
1184 	*tmp = NULL;
1185 
1186 	/* the device type may provide a specific name */
1187 	if (dev->type && dev->type->devnode)
1188 		*tmp = dev->type->devnode(dev, mode);
1189 	if (*tmp)
1190 		return *tmp;
1191 
1192 	/* the class may provide a specific name */
1193 	if (dev->class && dev->class->devnode)
1194 		*tmp = dev->class->devnode(dev, mode);
1195 	if (*tmp)
1196 		return *tmp;
1197 
1198 	/* return name without allocation, tmp == NULL */
1199 	if (strchr(dev_name(dev), '!') == NULL)
1200 		return dev_name(dev);
1201 
1202 	/* replace '!' in the name with '/' */
1203 	*tmp = kstrdup(dev_name(dev), GFP_KERNEL);
1204 	if (!*tmp)
1205 		return NULL;
1206 	while ((s = strchr(*tmp, '!')))
1207 		s[0] = '/';
1208 	return *tmp;
1209 }
1210 
1211 /**
1212  * device_for_each_child - device child iterator.
1213  * @parent: parent struct device.
1214  * @data: data for the callback.
1215  * @fn: function to be called for each device.
1216  *
1217  * Iterate over @parent's child devices, and call @fn for each,
1218  * passing it @data.
1219  *
1220  * We check the return of @fn each time. If it returns anything
1221  * other than 0, we break out and return that value.
1222  */
1223 int device_for_each_child(struct device *parent, void *data,
1224 			  int (*fn)(struct device *dev, void *data))
1225 {
1226 	struct klist_iter i;
1227 	struct device *child;
1228 	int error = 0;
1229 
1230 	if (!parent->p)
1231 		return 0;
1232 
1233 	klist_iter_init(&parent->p->klist_children, &i);
1234 	while ((child = next_device(&i)) && !error)
1235 		error = fn(child, data);
1236 	klist_iter_exit(&i);
1237 	return error;
1238 }
1239 
1240 /**
1241  * device_find_child - device iterator for locating a particular device.
1242  * @parent: parent struct device
1243  * @data: Data to pass to match function
1244  * @match: Callback function to check device
1245  *
1246  * This is similar to the device_for_each_child() function above, but it
1247  * returns a reference to a device that is 'found' for later use, as
1248  * determined by the @match callback.
1249  *
1250  * The callback should return 0 if the device doesn't match and non-zero
1251  * if it does.  If the callback returns non-zero and a reference to the
1252  * current device can be obtained, this function will return to the caller
1253  * and not iterate over any more devices.
1254  */
1255 struct device *device_find_child(struct device *parent, void *data,
1256 				 int (*match)(struct device *dev, void *data))
1257 {
1258 	struct klist_iter i;
1259 	struct device *child;
1260 
1261 	if (!parent)
1262 		return NULL;
1263 
1264 	klist_iter_init(&parent->p->klist_children, &i);
1265 	while ((child = next_device(&i)))
1266 		if (match(child, data) && get_device(child))
1267 			break;
1268 	klist_iter_exit(&i);
1269 	return child;
1270 }
1271 
1272 int __init devices_init(void)
1273 {
1274 	devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
1275 	if (!devices_kset)
1276 		return -ENOMEM;
1277 	dev_kobj = kobject_create_and_add("dev", NULL);
1278 	if (!dev_kobj)
1279 		goto dev_kobj_err;
1280 	sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
1281 	if (!sysfs_dev_block_kobj)
1282 		goto block_kobj_err;
1283 	sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
1284 	if (!sysfs_dev_char_kobj)
1285 		goto char_kobj_err;
1286 
1287 	return 0;
1288 
1289  char_kobj_err:
1290 	kobject_put(sysfs_dev_block_kobj);
1291  block_kobj_err:
1292 	kobject_put(dev_kobj);
1293  dev_kobj_err:
1294 	kset_unregister(devices_kset);
1295 	return -ENOMEM;
1296 }
1297 
1298 EXPORT_SYMBOL_GPL(device_for_each_child);
1299 EXPORT_SYMBOL_GPL(device_find_child);
1300 
1301 EXPORT_SYMBOL_GPL(device_initialize);
1302 EXPORT_SYMBOL_GPL(device_add);
1303 EXPORT_SYMBOL_GPL(device_register);
1304 
1305 EXPORT_SYMBOL_GPL(device_del);
1306 EXPORT_SYMBOL_GPL(device_unregister);
1307 EXPORT_SYMBOL_GPL(get_device);
1308 EXPORT_SYMBOL_GPL(put_device);
1309 
1310 EXPORT_SYMBOL_GPL(device_create_file);
1311 EXPORT_SYMBOL_GPL(device_remove_file);
1312 
1313 struct root_device
1314 {
1315 	struct device dev;
1316 	struct module *owner;
1317 };
1318 
1319 #define to_root_device(dev) container_of(dev, struct root_device, dev)
1320 
1321 static void root_device_release(struct device *dev)
1322 {
1323 	kfree(to_root_device(dev));
1324 }
1325 
1326 /**
1327  * __root_device_register - allocate and register a root device
1328  * @name: root device name
1329  * @owner: owner module of the root device, usually THIS_MODULE
1330  *
1331  * This function allocates a root device and registers it
1332  * using device_register(). In order to free the returned
1333  * device, use root_device_unregister().
1334  *
1335  * Root devices are dummy devices which allow other devices
1336  * to be grouped under /sys/devices. Use this function to
1337  * allocate a root device and then use it as the parent of
1338  * any device which should appear under /sys/devices/{name}
1339  *
1340  * The /sys/devices/{name} directory will also contain a
1341  * 'module' symlink which points to the @owner directory
1342  * in sysfs.
1343  *
1344  * Note: You probably want to use root_device_register().
1345  */
1346 struct device *__root_device_register(const char *name, struct module *owner)
1347 {
1348 	struct root_device *root;
1349 	int err = -ENOMEM;
1350 
1351 	root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
1352 	if (!root)
1353 		return ERR_PTR(err);
1354 
1355 	err = dev_set_name(&root->dev, "%s", name);
1356 	if (err) {
1357 		kfree(root);
1358 		return ERR_PTR(err);
1359 	}
1360 
1361 	root->dev.release = root_device_release;
1362 
1363 	err = device_register(&root->dev);
1364 	if (err) {
1365 		put_device(&root->dev);
1366 		return ERR_PTR(err);
1367 	}
1368 
1369 #ifdef CONFIG_MODULE	/* gotta find a "cleaner" way to do this */
1370 	if (owner) {
1371 		struct module_kobject *mk = &owner->mkobj;
1372 
1373 		err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
1374 		if (err) {
1375 			device_unregister(&root->dev);
1376 			return ERR_PTR(err);
1377 		}
1378 		root->owner = owner;
1379 	}
1380 #endif
1381 
1382 	return &root->dev;
1383 }
1384 EXPORT_SYMBOL_GPL(__root_device_register);
1385 
1386 /**
1387  * root_device_unregister - unregister and free a root device
1388  * @dev: device going away
1389  *
1390  * This function unregisters and cleans up a device that was created by
1391  * root_device_register().
1392  */
1393 void root_device_unregister(struct device *dev)
1394 {
1395 	struct root_device *root = to_root_device(dev);
1396 
1397 	if (root->owner)
1398 		sysfs_remove_link(&root->dev.kobj, "module");
1399 
1400 	device_unregister(dev);
1401 }
1402 EXPORT_SYMBOL_GPL(root_device_unregister);
1403 
1404 
1405 static void device_create_release(struct device *dev)
1406 {
1407 	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1408 	kfree(dev);
1409 }
1410 
1411 /**
1412  * device_create_vargs - creates a device and registers it with sysfs
1413  * @class: pointer to the struct class that this device should be registered to
1414  * @parent: pointer to the parent struct device of this new device, if any
1415  * @devt: the dev_t for the char device to be added
1416  * @drvdata: the data to be added to the device for callbacks
1417  * @fmt: string for the device's name
1418  * @args: va_list for the device's name
1419  *
1420  * This function can be used by char device classes.  A struct device
1421  * will be created in sysfs, registered to the specified class.
1422  *
1423  * A "dev" file will be created, showing the dev_t for the device, if
1424  * the dev_t is not 0,0.
1425  * If a pointer to a parent struct device is passed in, the newly created
1426  * struct device will be a child of that device in sysfs.
1427  * The pointer to the struct device will be returned from the call.
1428  * Any further sysfs files that might be required can be created using this
1429  * pointer.
1430  *
1431  * Note: the struct class passed to this function must have previously
1432  * been created with a call to class_create().
1433  */
1434 struct device *device_create_vargs(struct class *class, struct device *parent,
1435 				   dev_t devt, void *drvdata, const char *fmt,
1436 				   va_list args)
1437 {
1438 	struct device *dev = NULL;
1439 	int retval = -ENODEV;
1440 
1441 	if (class == NULL || IS_ERR(class))
1442 		goto error;
1443 
1444 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1445 	if (!dev) {
1446 		retval = -ENOMEM;
1447 		goto error;
1448 	}
1449 
1450 	dev->devt = devt;
1451 	dev->class = class;
1452 	dev->parent = parent;
1453 	dev->release = device_create_release;
1454 	dev_set_drvdata(dev, drvdata);
1455 
1456 	retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
1457 	if (retval)
1458 		goto error;
1459 
1460 	retval = device_register(dev);
1461 	if (retval)
1462 		goto error;
1463 
1464 	return dev;
1465 
1466 error:
1467 	put_device(dev);
1468 	return ERR_PTR(retval);
1469 }
1470 EXPORT_SYMBOL_GPL(device_create_vargs);
1471 
1472 /**
1473  * device_create - creates a device and registers it with sysfs
1474  * @class: pointer to the struct class that this device should be registered to
1475  * @parent: pointer to the parent struct device of this new device, if any
1476  * @devt: the dev_t for the char device to be added
1477  * @drvdata: the data to be added to the device for callbacks
1478  * @fmt: string for the device's name
1479  *
1480  * This function can be used by char device classes.  A struct device
1481  * will be created in sysfs, registered to the specified class.
1482  *
1483  * A "dev" file will be created, showing the dev_t for the device, if
1484  * the dev_t is not 0,0.
1485  * If a pointer to a parent struct device is passed in, the newly created
1486  * struct device will be a child of that device in sysfs.
1487  * The pointer to the struct device will be returned from the call.
1488  * Any further sysfs files that might be required can be created using this
1489  * pointer.
1490  *
1491  * Note: the struct class passed to this function must have previously
1492  * been created with a call to class_create().
1493  */
1494 struct device *device_create(struct class *class, struct device *parent,
1495 			     dev_t devt, void *drvdata, const char *fmt, ...)
1496 {
1497 	va_list vargs;
1498 	struct device *dev;
1499 
1500 	va_start(vargs, fmt);
1501 	dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
1502 	va_end(vargs);
1503 	return dev;
1504 }
1505 EXPORT_SYMBOL_GPL(device_create);
1506 
1507 static int __match_devt(struct device *dev, void *data)
1508 {
1509 	dev_t *devt = data;
1510 
1511 	return dev->devt == *devt;
1512 }
1513 
1514 /**
1515  * device_destroy - removes a device that was created with device_create()
1516  * @class: pointer to the struct class that this device was registered with
1517  * @devt: the dev_t of the device that was previously registered
1518  *
1519  * This call unregisters and cleans up a device that was created with a
1520  * call to device_create().
1521  */
1522 void device_destroy(struct class *class, dev_t devt)
1523 {
1524 	struct device *dev;
1525 
1526 	dev = class_find_device(class, NULL, &devt, __match_devt);
1527 	if (dev) {
1528 		put_device(dev);
1529 		device_unregister(dev);
1530 	}
1531 }
1532 EXPORT_SYMBOL_GPL(device_destroy);
1533 
1534 /**
1535  * device_rename - renames a device
1536  * @dev: the pointer to the struct device to be renamed
1537  * @new_name: the new name of the device
1538  *
1539  * It is the responsibility of the caller to provide mutual
1540  * exclusion between two different calls of device_rename
1541  * on the same device to ensure that new_name is valid and
1542  * won't conflict with other devices.
1543  */
1544 int device_rename(struct device *dev, char *new_name)
1545 {
1546 	char *old_class_name = NULL;
1547 	char *new_class_name = NULL;
1548 	char *old_device_name = NULL;
1549 	int error;
1550 
1551 	dev = get_device(dev);
1552 	if (!dev)
1553 		return -EINVAL;
1554 
1555 	pr_debug("device: '%s': %s: renaming to '%s'\n", dev_name(dev),
1556 		 __func__, new_name);
1557 
1558 #ifdef CONFIG_SYSFS_DEPRECATED
1559 	if ((dev->class) && (dev->parent))
1560 		old_class_name = make_class_name(dev->class->name, &dev->kobj);
1561 #endif
1562 
1563 	old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
1564 	if (!old_device_name) {
1565 		error = -ENOMEM;
1566 		goto out;
1567 	}
1568 
1569 	error = kobject_rename(&dev->kobj, new_name);
1570 	if (error)
1571 		goto out;
1572 
1573 #ifdef CONFIG_SYSFS_DEPRECATED
1574 	if (old_class_name) {
1575 		new_class_name = make_class_name(dev->class->name, &dev->kobj);
1576 		if (new_class_name) {
1577 			error = sysfs_create_link_nowarn(&dev->parent->kobj,
1578 							 &dev->kobj,
1579 							 new_class_name);
1580 			if (error)
1581 				goto out;
1582 			sysfs_remove_link(&dev->parent->kobj, old_class_name);
1583 		}
1584 	}
1585 #else
1586 	if (dev->class) {
1587 		error = sysfs_create_link_nowarn(&dev->class->p->class_subsys.kobj,
1588 						 &dev->kobj, dev_name(dev));
1589 		if (error)
1590 			goto out;
1591 		sysfs_remove_link(&dev->class->p->class_subsys.kobj,
1592 				  old_device_name);
1593 	}
1594 #endif
1595 
1596 out:
1597 	put_device(dev);
1598 
1599 	kfree(new_class_name);
1600 	kfree(old_class_name);
1601 	kfree(old_device_name);
1602 
1603 	return error;
1604 }
1605 EXPORT_SYMBOL_GPL(device_rename);
1606 
1607 static int device_move_class_links(struct device *dev,
1608 				   struct device *old_parent,
1609 				   struct device *new_parent)
1610 {
1611 	int error = 0;
1612 #ifdef CONFIG_SYSFS_DEPRECATED
1613 	char *class_name;
1614 
1615 	class_name = make_class_name(dev->class->name, &dev->kobj);
1616 	if (!class_name) {
1617 		error = -ENOMEM;
1618 		goto out;
1619 	}
1620 	if (old_parent) {
1621 		sysfs_remove_link(&dev->kobj, "device");
1622 		sysfs_remove_link(&old_parent->kobj, class_name);
1623 	}
1624 	if (new_parent) {
1625 		error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1626 					  "device");
1627 		if (error)
1628 			goto out;
1629 		error = sysfs_create_link(&new_parent->kobj, &dev->kobj,
1630 					  class_name);
1631 		if (error)
1632 			sysfs_remove_link(&dev->kobj, "device");
1633 	} else
1634 		error = 0;
1635 out:
1636 	kfree(class_name);
1637 	return error;
1638 #else
1639 	if (old_parent)
1640 		sysfs_remove_link(&dev->kobj, "device");
1641 	if (new_parent)
1642 		error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1643 					  "device");
1644 	return error;
1645 #endif
1646 }
1647 
1648 /**
1649  * device_move - moves a device to a new parent
1650  * @dev: the pointer to the struct device to be moved
1651  * @new_parent: the new parent of the device (can by NULL)
1652  * @dpm_order: how to reorder the dpm_list
1653  */
1654 int device_move(struct device *dev, struct device *new_parent,
1655 		enum dpm_order dpm_order)
1656 {
1657 	int error;
1658 	struct device *old_parent;
1659 	struct kobject *new_parent_kobj;
1660 
1661 	dev = get_device(dev);
1662 	if (!dev)
1663 		return -EINVAL;
1664 
1665 	device_pm_lock();
1666 	new_parent = get_device(new_parent);
1667 	new_parent_kobj = get_device_parent(dev, new_parent);
1668 
1669 	pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
1670 		 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
1671 	error = kobject_move(&dev->kobj, new_parent_kobj);
1672 	if (error) {
1673 		cleanup_glue_dir(dev, new_parent_kobj);
1674 		put_device(new_parent);
1675 		goto out;
1676 	}
1677 	old_parent = dev->parent;
1678 	dev->parent = new_parent;
1679 	if (old_parent)
1680 		klist_remove(&dev->p->knode_parent);
1681 	if (new_parent) {
1682 		klist_add_tail(&dev->p->knode_parent,
1683 			       &new_parent->p->klist_children);
1684 		set_dev_node(dev, dev_to_node(new_parent));
1685 	}
1686 
1687 	if (!dev->class)
1688 		goto out_put;
1689 	error = device_move_class_links(dev, old_parent, new_parent);
1690 	if (error) {
1691 		/* We ignore errors on cleanup since we're hosed anyway... */
1692 		device_move_class_links(dev, new_parent, old_parent);
1693 		if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
1694 			if (new_parent)
1695 				klist_remove(&dev->p->knode_parent);
1696 			dev->parent = old_parent;
1697 			if (old_parent) {
1698 				klist_add_tail(&dev->p->knode_parent,
1699 					       &old_parent->p->klist_children);
1700 				set_dev_node(dev, dev_to_node(old_parent));
1701 			}
1702 		}
1703 		cleanup_glue_dir(dev, new_parent_kobj);
1704 		put_device(new_parent);
1705 		goto out;
1706 	}
1707 	switch (dpm_order) {
1708 	case DPM_ORDER_NONE:
1709 		break;
1710 	case DPM_ORDER_DEV_AFTER_PARENT:
1711 		device_pm_move_after(dev, new_parent);
1712 		break;
1713 	case DPM_ORDER_PARENT_BEFORE_DEV:
1714 		device_pm_move_before(new_parent, dev);
1715 		break;
1716 	case DPM_ORDER_DEV_LAST:
1717 		device_pm_move_last(dev);
1718 		break;
1719 	}
1720 out_put:
1721 	put_device(old_parent);
1722 out:
1723 	device_pm_unlock();
1724 	put_device(dev);
1725 	return error;
1726 }
1727 EXPORT_SYMBOL_GPL(device_move);
1728 
1729 /**
1730  * device_shutdown - call ->shutdown() on each device to shutdown.
1731  */
1732 void device_shutdown(void)
1733 {
1734 	struct device *dev, *devn;
1735 
1736 	list_for_each_entry_safe_reverse(dev, devn, &devices_kset->list,
1737 				kobj.entry) {
1738 		if (dev->bus && dev->bus->shutdown) {
1739 			dev_dbg(dev, "shutdown\n");
1740 			dev->bus->shutdown(dev);
1741 		} else if (dev->driver && dev->driver->shutdown) {
1742 			dev_dbg(dev, "shutdown\n");
1743 			dev->driver->shutdown(dev);
1744 		}
1745 	}
1746 	async_synchronize_full();
1747 }
1748