2 * drivers/base/core.c - core driver model code (device registration, etc)
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.
9 * This file is released under the GPLv2
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/mutex.h>
24 #include <linux/async.h>
25 #include <linux/pm_runtime.h>
28 #include "power/power.h"
30 #ifdef CONFIG_SYSFS_DEPRECATED
31 #ifdef CONFIG_SYSFS_DEPRECATED_V2
32 long sysfs_deprecated = 1;
34 long sysfs_deprecated = 0;
36 static __init int sysfs_deprecated_setup(char *arg)
38 return strict_strtol(arg, 10, &sysfs_deprecated);
40 early_param("sysfs.deprecated", sysfs_deprecated_setup);
43 int (*platform_notify)(struct device *dev) = NULL;
44 int (*platform_notify_remove)(struct device *dev) = NULL;
45 static struct kobject *dev_kobj;
46 struct kobject *sysfs_dev_char_kobj;
47 struct kobject *sysfs_dev_block_kobj;
50 static inline int device_is_not_partition(struct device *dev)
52 return !(dev->type == &part_type);
55 static inline int device_is_not_partition(struct device *dev)
62 * dev_driver_string - Return a device's driver name, if at all possible
63 * @dev: struct device to get the name of
65 * Will return the device's driver's name if it is bound to a device. If
66 * the device is not bound to a device, it will return the name of the bus
67 * it is attached to. If it is not attached to a bus either, an empty
68 * string will be returned.
70 const char *dev_driver_string(const struct device *dev)
72 struct device_driver *drv;
74 /* dev->driver can change to NULL underneath us because of unbinding,
75 * so be careful about accessing it. dev->bus and dev->class should
76 * never change once they are set, so they don't need special care.
78 drv = ACCESS_ONCE(dev->driver);
79 return drv ? drv->name :
80 (dev->bus ? dev->bus->name :
81 (dev->class ? dev->class->name : ""));
83 EXPORT_SYMBOL(dev_driver_string);
85 #define to_dev(obj) container_of(obj, struct device, kobj)
86 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
88 static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
91 struct device_attribute *dev_attr = to_dev_attr(attr);
92 struct device *dev = to_dev(kobj);
96 ret = dev_attr->show(dev, dev_attr, buf);
97 if (ret >= (ssize_t)PAGE_SIZE) {
98 print_symbol("dev_attr_show: %s returned bad count\n",
99 (unsigned long)dev_attr->show);
104 static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
105 const char *buf, size_t count)
107 struct device_attribute *dev_attr = to_dev_attr(attr);
108 struct device *dev = to_dev(kobj);
112 ret = dev_attr->store(dev, dev_attr, buf, count);
116 static const struct sysfs_ops dev_sysfs_ops = {
117 .show = dev_attr_show,
118 .store = dev_attr_store,
121 #define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
123 ssize_t device_store_ulong(struct device *dev,
124 struct device_attribute *attr,
125 const char *buf, size_t size)
127 struct dev_ext_attribute *ea = to_ext_attr(attr);
129 unsigned long new = simple_strtoul(buf, &end, 0);
132 *(unsigned long *)(ea->var) = new;
133 /* Always return full write size even if we didn't consume all */
136 EXPORT_SYMBOL_GPL(device_store_ulong);
138 ssize_t device_show_ulong(struct device *dev,
139 struct device_attribute *attr,
142 struct dev_ext_attribute *ea = to_ext_attr(attr);
143 return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
145 EXPORT_SYMBOL_GPL(device_show_ulong);
147 ssize_t device_store_int(struct device *dev,
148 struct device_attribute *attr,
149 const char *buf, size_t size)
151 struct dev_ext_attribute *ea = to_ext_attr(attr);
153 long new = simple_strtol(buf, &end, 0);
154 if (end == buf || new > INT_MAX || new < INT_MIN)
156 *(int *)(ea->var) = new;
157 /* Always return full write size even if we didn't consume all */
160 EXPORT_SYMBOL_GPL(device_store_int);
162 ssize_t device_show_int(struct device *dev,
163 struct device_attribute *attr,
166 struct dev_ext_attribute *ea = to_ext_attr(attr);
168 return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
170 EXPORT_SYMBOL_GPL(device_show_int);
173 * device_release - free device structure.
174 * @kobj: device's kobject.
176 * This is called once the reference count for the object
177 * reaches 0. We forward the call to the device's release
178 * method, which should handle actually freeing the structure.
180 static void device_release(struct kobject *kobj)
182 struct device *dev = to_dev(kobj);
183 struct device_private *p = dev->p;
187 else if (dev->type && dev->type->release)
188 dev->type->release(dev);
189 else if (dev->class && dev->class->dev_release)
190 dev->class->dev_release(dev);
192 WARN(1, KERN_ERR "Device '%s' does not have a release() "
193 "function, it is broken and must be fixed.\n",
198 static const void *device_namespace(struct kobject *kobj)
200 struct device *dev = to_dev(kobj);
201 const void *ns = NULL;
203 if (dev->class && dev->class->ns_type)
204 ns = dev->class->namespace(dev);
209 static struct kobj_type device_ktype = {
210 .release = device_release,
211 .sysfs_ops = &dev_sysfs_ops,
212 .namespace = device_namespace,
216 static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
218 struct kobj_type *ktype = get_ktype(kobj);
220 if (ktype == &device_ktype) {
221 struct device *dev = to_dev(kobj);
230 static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
232 struct device *dev = to_dev(kobj);
235 return dev->bus->name;
237 return dev->class->name;
241 static int dev_uevent(struct kset *kset, struct kobject *kobj,
242 struct kobj_uevent_env *env)
244 struct device *dev = to_dev(kobj);
247 /* add device node properties if present */
248 if (MAJOR(dev->devt)) {
253 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
254 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
255 name = device_get_devnode(dev, &mode, &tmp);
257 add_uevent_var(env, "DEVNAME=%s", name);
260 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
264 if (dev->type && dev->type->name)
265 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
268 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
270 /* have the bus specific function add its stuff */
271 if (dev->bus && dev->bus->uevent) {
272 retval = dev->bus->uevent(dev, env);
274 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
275 dev_name(dev), __func__, retval);
278 /* have the class specific function add its stuff */
279 if (dev->class && dev->class->dev_uevent) {
280 retval = dev->class->dev_uevent(dev, env);
282 pr_debug("device: '%s': %s: class uevent() "
283 "returned %d\n", dev_name(dev),
287 /* have the device type specific function add its stuff */
288 if (dev->type && dev->type->uevent) {
289 retval = dev->type->uevent(dev, env);
291 pr_debug("device: '%s': %s: dev_type uevent() "
292 "returned %d\n", dev_name(dev),
299 static const struct kset_uevent_ops device_uevent_ops = {
300 .filter = dev_uevent_filter,
301 .name = dev_uevent_name,
302 .uevent = dev_uevent,
305 static ssize_t show_uevent(struct device *dev, struct device_attribute *attr,
308 struct kobject *top_kobj;
310 struct kobj_uevent_env *env = NULL;
315 /* search the kset, the device belongs to */
316 top_kobj = &dev->kobj;
317 while (!top_kobj->kset && top_kobj->parent)
318 top_kobj = top_kobj->parent;
322 kset = top_kobj->kset;
323 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
327 if (kset->uevent_ops && kset->uevent_ops->filter)
328 if (!kset->uevent_ops->filter(kset, &dev->kobj))
331 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
335 /* let the kset specific function add its keys */
336 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
340 /* copy keys to file */
341 for (i = 0; i < env->envp_idx; i++)
342 count += sprintf(&buf[count], "%s\n", env->envp[i]);
348 static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
349 const char *buf, size_t count)
351 enum kobject_action action;
353 if (kobject_action_type(buf, count, &action) == 0)
354 kobject_uevent(&dev->kobj, action);
356 dev_err(dev, "uevent: unknown action-string\n");
360 static struct device_attribute uevent_attr =
361 __ATTR(uevent, S_IRUGO | S_IWUSR, show_uevent, store_uevent);
363 static int device_add_attributes(struct device *dev,
364 struct device_attribute *attrs)
370 for (i = 0; attr_name(attrs[i]); i++) {
371 error = device_create_file(dev, &attrs[i]);
377 device_remove_file(dev, &attrs[i]);
382 static void device_remove_attributes(struct device *dev,
383 struct device_attribute *attrs)
388 for (i = 0; attr_name(attrs[i]); i++)
389 device_remove_file(dev, &attrs[i]);
392 static int device_add_bin_attributes(struct device *dev,
393 struct bin_attribute *attrs)
399 for (i = 0; attr_name(attrs[i]); i++) {
400 error = device_create_bin_file(dev, &attrs[i]);
406 device_remove_bin_file(dev, &attrs[i]);
411 static void device_remove_bin_attributes(struct device *dev,
412 struct bin_attribute *attrs)
417 for (i = 0; attr_name(attrs[i]); i++)
418 device_remove_bin_file(dev, &attrs[i]);
421 static int device_add_groups(struct device *dev,
422 const struct attribute_group **groups)
428 for (i = 0; groups[i]; i++) {
429 error = sysfs_create_group(&dev->kobj, groups[i]);
432 sysfs_remove_group(&dev->kobj,
441 static void device_remove_groups(struct device *dev,
442 const struct attribute_group **groups)
447 for (i = 0; groups[i]; i++)
448 sysfs_remove_group(&dev->kobj, groups[i]);
451 static int device_add_attrs(struct device *dev)
453 struct class *class = dev->class;
454 const struct device_type *type = dev->type;
458 error = device_add_attributes(dev, class->dev_attrs);
461 error = device_add_bin_attributes(dev, class->dev_bin_attrs);
463 goto err_remove_class_attrs;
467 error = device_add_groups(dev, type->groups);
469 goto err_remove_class_bin_attrs;
472 error = device_add_groups(dev, dev->groups);
474 goto err_remove_type_groups;
478 err_remove_type_groups:
480 device_remove_groups(dev, type->groups);
481 err_remove_class_bin_attrs:
483 device_remove_bin_attributes(dev, class->dev_bin_attrs);
484 err_remove_class_attrs:
486 device_remove_attributes(dev, class->dev_attrs);
491 static void device_remove_attrs(struct device *dev)
493 struct class *class = dev->class;
494 const struct device_type *type = dev->type;
496 device_remove_groups(dev, dev->groups);
499 device_remove_groups(dev, type->groups);
502 device_remove_attributes(dev, class->dev_attrs);
503 device_remove_bin_attributes(dev, class->dev_bin_attrs);
508 static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
511 return print_dev_t(buf, dev->devt);
514 static struct device_attribute devt_attr =
515 __ATTR(dev, S_IRUGO, show_dev, NULL);
518 struct kset *devices_kset;
521 * device_create_file - create sysfs attribute file for device.
523 * @attr: device attribute descriptor.
525 int device_create_file(struct device *dev,
526 const struct device_attribute *attr)
530 error = sysfs_create_file(&dev->kobj, &attr->attr);
535 * device_remove_file - remove sysfs attribute file.
537 * @attr: device attribute descriptor.
539 void device_remove_file(struct device *dev,
540 const struct device_attribute *attr)
543 sysfs_remove_file(&dev->kobj, &attr->attr);
547 * device_create_bin_file - create sysfs binary attribute file for device.
549 * @attr: device binary attribute descriptor.
551 int device_create_bin_file(struct device *dev,
552 const struct bin_attribute *attr)
556 error = sysfs_create_bin_file(&dev->kobj, attr);
559 EXPORT_SYMBOL_GPL(device_create_bin_file);
562 * device_remove_bin_file - remove sysfs binary attribute file
564 * @attr: device binary attribute descriptor.
566 void device_remove_bin_file(struct device *dev,
567 const struct bin_attribute *attr)
570 sysfs_remove_bin_file(&dev->kobj, attr);
572 EXPORT_SYMBOL_GPL(device_remove_bin_file);
575 * device_schedule_callback_owner - helper to schedule a callback for a device
577 * @func: callback function to invoke later.
578 * @owner: module owning the callback routine
580 * Attribute methods must not unregister themselves or their parent device
581 * (which would amount to the same thing). Attempts to do so will deadlock,
582 * since unregistration is mutually exclusive with driver callbacks.
584 * Instead methods can call this routine, which will attempt to allocate
585 * and schedule a workqueue request to call back @func with @dev as its
586 * argument in the workqueue's process context. @dev will be pinned until
589 * This routine is usually called via the inline device_schedule_callback(),
590 * which automatically sets @owner to THIS_MODULE.
592 * Returns 0 if the request was submitted, -ENOMEM if storage could not
593 * be allocated, -ENODEV if a reference to @owner isn't available.
595 * NOTE: This routine won't work if CONFIG_SYSFS isn't set! It uses an
596 * underlying sysfs routine (since it is intended for use by attribute
597 * methods), and if sysfs isn't available you'll get nothing but -ENOSYS.
599 int device_schedule_callback_owner(struct device *dev,
600 void (*func)(struct device *), struct module *owner)
602 return sysfs_schedule_callback(&dev->kobj,
603 (void (*)(void *)) func, dev, owner);
605 EXPORT_SYMBOL_GPL(device_schedule_callback_owner);
607 static void klist_children_get(struct klist_node *n)
609 struct device_private *p = to_device_private_parent(n);
610 struct device *dev = p->device;
615 static void klist_children_put(struct klist_node *n)
617 struct device_private *p = to_device_private_parent(n);
618 struct device *dev = p->device;
624 * device_initialize - init device structure.
627 * This prepares the device for use by other layers by initializing
629 * It is the first half of device_register(), if called by
630 * that function, though it can also be called separately, so one
631 * may use @dev's fields. In particular, get_device()/put_device()
632 * may be used for reference counting of @dev after calling this
635 * All fields in @dev must be initialized by the caller to 0, except
636 * for those explicitly set to some other value. The simplest
637 * approach is to use kzalloc() to allocate the structure containing
640 * NOTE: Use put_device() to give up your reference instead of freeing
641 * @dev directly once you have called this function.
643 void device_initialize(struct device *dev)
645 dev->kobj.kset = devices_kset;
646 kobject_init(&dev->kobj, &device_ktype);
647 INIT_LIST_HEAD(&dev->dma_pools);
648 mutex_init(&dev->mutex);
649 lockdep_set_novalidate_class(&dev->mutex);
650 spin_lock_init(&dev->devres_lock);
651 INIT_LIST_HEAD(&dev->devres_head);
653 set_dev_node(dev, -1);
656 static struct kobject *virtual_device_parent(struct device *dev)
658 static struct kobject *virtual_dir = NULL;
661 virtual_dir = kobject_create_and_add("virtual",
662 &devices_kset->kobj);
672 #define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
674 static void class_dir_release(struct kobject *kobj)
676 struct class_dir *dir = to_class_dir(kobj);
681 struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
683 struct class_dir *dir = to_class_dir(kobj);
684 return dir->class->ns_type;
687 static struct kobj_type class_dir_ktype = {
688 .release = class_dir_release,
689 .sysfs_ops = &kobj_sysfs_ops,
690 .child_ns_type = class_dir_child_ns_type
693 static struct kobject *
694 class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
696 struct class_dir *dir;
699 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
704 kobject_init(&dir->kobj, &class_dir_ktype);
706 dir->kobj.kset = &class->p->glue_dirs;
708 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
710 kobject_put(&dir->kobj);
717 static struct kobject *get_device_parent(struct device *dev,
718 struct device *parent)
721 static DEFINE_MUTEX(gdp_mutex);
722 struct kobject *kobj = NULL;
723 struct kobject *parent_kobj;
727 /* block disks show up in /sys/block */
728 if (sysfs_deprecated && dev->class == &block_class) {
729 if (parent && parent->class == &block_class)
730 return &parent->kobj;
731 return &block_class.p->subsys.kobj;
736 * If we have no parent, we live in "virtual".
737 * Class-devices with a non class-device as parent, live
738 * in a "glue" directory to prevent namespace collisions.
741 parent_kobj = virtual_device_parent(dev);
742 else if (parent->class && !dev->class->ns_type)
743 return &parent->kobj;
745 parent_kobj = &parent->kobj;
747 mutex_lock(&gdp_mutex);
749 /* find our class-directory at the parent and reference it */
750 spin_lock(&dev->class->p->glue_dirs.list_lock);
751 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
752 if (k->parent == parent_kobj) {
753 kobj = kobject_get(k);
756 spin_unlock(&dev->class->p->glue_dirs.list_lock);
758 mutex_unlock(&gdp_mutex);
762 /* or create a new class-directory at the parent device */
763 k = class_dir_create_and_add(dev->class, parent_kobj);
764 /* do not emit an uevent for this simple "glue" directory */
765 mutex_unlock(&gdp_mutex);
769 /* subsystems can specify a default root directory for their devices */
770 if (!parent && dev->bus && dev->bus->dev_root)
771 return &dev->bus->dev_root->kobj;
774 return &parent->kobj;
778 static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
780 /* see if we live in a "glue" directory */
781 if (!glue_dir || !dev->class ||
782 glue_dir->kset != &dev->class->p->glue_dirs)
785 kobject_put(glue_dir);
788 static void cleanup_device_parent(struct device *dev)
790 cleanup_glue_dir(dev, dev->kobj.parent);
793 static int device_add_class_symlinks(struct device *dev)
800 error = sysfs_create_link(&dev->kobj,
801 &dev->class->p->subsys.kobj,
806 if (dev->parent && device_is_not_partition(dev)) {
807 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
814 /* /sys/block has directories and does not need symlinks */
815 if (sysfs_deprecated && dev->class == &block_class)
819 /* link in the class directory pointing to the device */
820 error = sysfs_create_link(&dev->class->p->subsys.kobj,
821 &dev->kobj, dev_name(dev));
828 sysfs_remove_link(&dev->kobj, "device");
831 sysfs_remove_link(&dev->kobj, "subsystem");
836 static void device_remove_class_symlinks(struct device *dev)
841 if (dev->parent && device_is_not_partition(dev))
842 sysfs_remove_link(&dev->kobj, "device");
843 sysfs_remove_link(&dev->kobj, "subsystem");
845 if (sysfs_deprecated && dev->class == &block_class)
848 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
852 * dev_set_name - set a device name
854 * @fmt: format string for the device's name
856 int dev_set_name(struct device *dev, const char *fmt, ...)
861 va_start(vargs, fmt);
862 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
866 EXPORT_SYMBOL_GPL(dev_set_name);
869 * device_to_dev_kobj - select a /sys/dev/ directory for the device
872 * By default we select char/ for new entries. Setting class->dev_obj
873 * to NULL prevents an entry from being created. class->dev_kobj must
874 * be set (or cleared) before any devices are registered to the class
875 * otherwise device_create_sys_dev_entry() and
876 * device_remove_sys_dev_entry() will disagree about the the presence
879 static struct kobject *device_to_dev_kobj(struct device *dev)
881 struct kobject *kobj;
884 kobj = dev->class->dev_kobj;
886 kobj = sysfs_dev_char_kobj;
891 static int device_create_sys_dev_entry(struct device *dev)
893 struct kobject *kobj = device_to_dev_kobj(dev);
898 format_dev_t(devt_str, dev->devt);
899 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
905 static void device_remove_sys_dev_entry(struct device *dev)
907 struct kobject *kobj = device_to_dev_kobj(dev);
911 format_dev_t(devt_str, dev->devt);
912 sysfs_remove_link(kobj, devt_str);
916 int device_private_init(struct device *dev)
918 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
921 dev->p->device = dev;
922 klist_init(&dev->p->klist_children, klist_children_get,
924 INIT_LIST_HEAD(&dev->p->deferred_probe);
929 * device_add - add device to device hierarchy.
932 * This is part 2 of device_register(), though may be called
933 * separately _iff_ device_initialize() has been called separately.
935 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
936 * to the global and sibling lists for the device, then
937 * adds it to the other relevant subsystems of the driver model.
939 * Do not call this routine or device_register() more than once for
940 * any device structure. The driver model core is not designed to work
941 * with devices that get unregistered and then spring back to life.
942 * (Among other things, it's very hard to guarantee that all references
943 * to the previous incarnation of @dev have been dropped.) Allocate
944 * and register a fresh new struct device instead.
946 * NOTE: _Never_ directly free @dev after calling this function, even
947 * if it returned an error! Always use put_device() to give up your
950 int device_add(struct device *dev)
952 struct device *parent = NULL;
953 struct kobject *kobj;
954 struct class_interface *class_intf;
957 dev = get_device(dev);
962 error = device_private_init(dev);
968 * for statically allocated devices, which should all be converted
969 * some day, we need to initialize the name. We prevent reading back
970 * the name, and force the use of dev_name()
972 if (dev->init_name) {
973 dev_set_name(dev, "%s", dev->init_name);
974 dev->init_name = NULL;
977 /* subsystems can specify simple device enumeration */
978 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
979 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
981 if (!dev_name(dev)) {
986 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
988 parent = get_device(dev->parent);
989 kobj = get_device_parent(dev, parent);
991 dev->kobj.parent = kobj;
993 /* use parent numa_node */
995 set_dev_node(dev, dev_to_node(parent));
997 /* first, register with generic layer. */
998 /* we require the name to be set before, and pass NULL */
999 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
1003 /* notify platform of device entry */
1004 if (platform_notify)
1005 platform_notify(dev);
1007 error = device_create_file(dev, &uevent_attr);
1011 if (MAJOR(dev->devt)) {
1012 error = device_create_file(dev, &devt_attr);
1014 goto ueventattrError;
1016 error = device_create_sys_dev_entry(dev);
1020 devtmpfs_create_node(dev);
1023 error = device_add_class_symlinks(dev);
1026 error = device_add_attrs(dev);
1029 error = bus_add_device(dev);
1032 error = dpm_sysfs_add(dev);
1037 /* Notify clients of device addition. This call must come
1038 * after dpm_sysfs_add() and before kobject_uevent().
1041 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1042 BUS_NOTIFY_ADD_DEVICE, dev);
1044 kobject_uevent(&dev->kobj, KOBJ_ADD);
1045 bus_probe_device(dev);
1047 klist_add_tail(&dev->p->knode_parent,
1048 &parent->p->klist_children);
1051 mutex_lock(&dev->class->p->mutex);
1052 /* tie the class to the device */
1053 klist_add_tail(&dev->knode_class,
1054 &dev->class->p->klist_devices);
1056 /* notify any interfaces that the device is here */
1057 list_for_each_entry(class_intf,
1058 &dev->class->p->interfaces, node)
1059 if (class_intf->add_dev)
1060 class_intf->add_dev(dev, class_intf);
1061 mutex_unlock(&dev->class->p->mutex);
1067 bus_remove_device(dev);
1069 device_remove_attrs(dev);
1071 device_remove_class_symlinks(dev);
1073 if (MAJOR(dev->devt))
1074 devtmpfs_delete_node(dev);
1075 if (MAJOR(dev->devt))
1076 device_remove_sys_dev_entry(dev);
1078 if (MAJOR(dev->devt))
1079 device_remove_file(dev, &devt_attr);
1081 device_remove_file(dev, &uevent_attr);
1083 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1084 kobject_del(&dev->kobj);
1086 cleanup_device_parent(dev);
1096 * device_register - register a device with the system.
1097 * @dev: pointer to the device structure
1099 * This happens in two clean steps - initialize the device
1100 * and add it to the system. The two steps can be called
1101 * separately, but this is the easiest and most common.
1102 * I.e. you should only call the two helpers separately if
1103 * have a clearly defined need to use and refcount the device
1104 * before it is added to the hierarchy.
1106 * For more information, see the kerneldoc for device_initialize()
1109 * NOTE: _Never_ directly free @dev after calling this function, even
1110 * if it returned an error! Always use put_device() to give up the
1111 * reference initialized in this function instead.
1113 int device_register(struct device *dev)
1115 device_initialize(dev);
1116 return device_add(dev);
1120 * get_device - increment reference count for device.
1123 * This simply forwards the call to kobject_get(), though
1124 * we do take care to provide for the case that we get a NULL
1125 * pointer passed in.
1127 struct device *get_device(struct device *dev)
1129 return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
1133 * put_device - decrement reference count.
1134 * @dev: device in question.
1136 void put_device(struct device *dev)
1138 /* might_sleep(); */
1140 kobject_put(&dev->kobj);
1144 * device_del - delete device from system.
1147 * This is the first part of the device unregistration
1148 * sequence. This removes the device from the lists we control
1149 * from here, has it removed from the other driver model
1150 * subsystems it was added to in device_add(), and removes it
1151 * from the kobject hierarchy.
1153 * NOTE: this should be called manually _iff_ device_add() was
1154 * also called manually.
1156 void device_del(struct device *dev)
1158 struct device *parent = dev->parent;
1159 struct class_interface *class_intf;
1161 /* Notify clients of device removal. This call must come
1162 * before dpm_sysfs_remove().
1165 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1166 BUS_NOTIFY_DEL_DEVICE, dev);
1167 device_pm_remove(dev);
1168 dpm_sysfs_remove(dev);
1170 klist_del(&dev->p->knode_parent);
1171 if (MAJOR(dev->devt)) {
1172 devtmpfs_delete_node(dev);
1173 device_remove_sys_dev_entry(dev);
1174 device_remove_file(dev, &devt_attr);
1177 device_remove_class_symlinks(dev);
1179 mutex_lock(&dev->class->p->mutex);
1180 /* notify any interfaces that the device is now gone */
1181 list_for_each_entry(class_intf,
1182 &dev->class->p->interfaces, node)
1183 if (class_intf->remove_dev)
1184 class_intf->remove_dev(dev, class_intf);
1185 /* remove the device from the class list */
1186 klist_del(&dev->knode_class);
1187 mutex_unlock(&dev->class->p->mutex);
1189 device_remove_file(dev, &uevent_attr);
1190 device_remove_attrs(dev);
1191 bus_remove_device(dev);
1192 driver_deferred_probe_del(dev);
1195 * Some platform devices are driven without driver attached
1196 * and managed resources may have been acquired. Make sure
1197 * all resources are released.
1199 devres_release_all(dev);
1201 /* Notify the platform of the removal, in case they
1202 * need to do anything...
1204 if (platform_notify_remove)
1205 platform_notify_remove(dev);
1206 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1207 cleanup_device_parent(dev);
1208 kobject_del(&dev->kobj);
1213 * device_unregister - unregister device from system.
1214 * @dev: device going away.
1216 * We do this in two parts, like we do device_register(). First,
1217 * we remove it from all the subsystems with device_del(), then
1218 * we decrement the reference count via put_device(). If that
1219 * is the final reference count, the device will be cleaned up
1220 * via device_release() above. Otherwise, the structure will
1221 * stick around until the final reference to the device is dropped.
1223 void device_unregister(struct device *dev)
1225 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1230 static struct device *next_device(struct klist_iter *i)
1232 struct klist_node *n = klist_next(i);
1233 struct device *dev = NULL;
1234 struct device_private *p;
1237 p = to_device_private_parent(n);
1244 * device_get_devnode - path of device node file
1246 * @mode: returned file access mode
1247 * @tmp: possibly allocated string
1249 * Return the relative path of a possible device node.
1250 * Non-default names may need to allocate a memory to compose
1251 * a name. This memory is returned in tmp and needs to be
1252 * freed by the caller.
1254 const char *device_get_devnode(struct device *dev,
1255 umode_t *mode, const char **tmp)
1261 /* the device type may provide a specific name */
1262 if (dev->type && dev->type->devnode)
1263 *tmp = dev->type->devnode(dev, mode);
1267 /* the class may provide a specific name */
1268 if (dev->class && dev->class->devnode)
1269 *tmp = dev->class->devnode(dev, mode);
1273 /* return name without allocation, tmp == NULL */
1274 if (strchr(dev_name(dev), '!') == NULL)
1275 return dev_name(dev);
1277 /* replace '!' in the name with '/' */
1278 *tmp = kstrdup(dev_name(dev), GFP_KERNEL);
1281 while ((s = strchr(*tmp, '!')))
1287 * device_for_each_child - device child iterator.
1288 * @parent: parent struct device.
1289 * @data: data for the callback.
1290 * @fn: function to be called for each device.
1292 * Iterate over @parent's child devices, and call @fn for each,
1295 * We check the return of @fn each time. If it returns anything
1296 * other than 0, we break out and return that value.
1298 int device_for_each_child(struct device *parent, void *data,
1299 int (*fn)(struct device *dev, void *data))
1301 struct klist_iter i;
1302 struct device *child;
1308 klist_iter_init(&parent->p->klist_children, &i);
1309 while ((child = next_device(&i)) && !error)
1310 error = fn(child, data);
1311 klist_iter_exit(&i);
1316 * device_find_child - device iterator for locating a particular device.
1317 * @parent: parent struct device
1318 * @data: Data to pass to match function
1319 * @match: Callback function to check device
1321 * This is similar to the device_for_each_child() function above, but it
1322 * returns a reference to a device that is 'found' for later use, as
1323 * determined by the @match callback.
1325 * The callback should return 0 if the device doesn't match and non-zero
1326 * if it does. If the callback returns non-zero and a reference to the
1327 * current device can be obtained, this function will return to the caller
1328 * and not iterate over any more devices.
1330 struct device *device_find_child(struct device *parent, void *data,
1331 int (*match)(struct device *dev, void *data))
1333 struct klist_iter i;
1334 struct device *child;
1339 klist_iter_init(&parent->p->klist_children, &i);
1340 while ((child = next_device(&i)))
1341 if (match(child, data) && get_device(child))
1343 klist_iter_exit(&i);
1347 int __init devices_init(void)
1349 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
1352 dev_kobj = kobject_create_and_add("dev", NULL);
1355 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
1356 if (!sysfs_dev_block_kobj)
1357 goto block_kobj_err;
1358 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
1359 if (!sysfs_dev_char_kobj)
1365 kobject_put(sysfs_dev_block_kobj);
1367 kobject_put(dev_kobj);
1369 kset_unregister(devices_kset);
1373 EXPORT_SYMBOL_GPL(device_for_each_child);
1374 EXPORT_SYMBOL_GPL(device_find_child);
1376 EXPORT_SYMBOL_GPL(device_initialize);
1377 EXPORT_SYMBOL_GPL(device_add);
1378 EXPORT_SYMBOL_GPL(device_register);
1380 EXPORT_SYMBOL_GPL(device_del);
1381 EXPORT_SYMBOL_GPL(device_unregister);
1382 EXPORT_SYMBOL_GPL(get_device);
1383 EXPORT_SYMBOL_GPL(put_device);
1385 EXPORT_SYMBOL_GPL(device_create_file);
1386 EXPORT_SYMBOL_GPL(device_remove_file);
1388 struct root_device {
1390 struct module *owner;
1393 inline struct root_device *to_root_device(struct device *d)
1395 return container_of(d, struct root_device, dev);
1398 static void root_device_release(struct device *dev)
1400 kfree(to_root_device(dev));
1404 * __root_device_register - allocate and register a root device
1405 * @name: root device name
1406 * @owner: owner module of the root device, usually THIS_MODULE
1408 * This function allocates a root device and registers it
1409 * using device_register(). In order to free the returned
1410 * device, use root_device_unregister().
1412 * Root devices are dummy devices which allow other devices
1413 * to be grouped under /sys/devices. Use this function to
1414 * allocate a root device and then use it as the parent of
1415 * any device which should appear under /sys/devices/{name}
1417 * The /sys/devices/{name} directory will also contain a
1418 * 'module' symlink which points to the @owner directory
1421 * Returns &struct device pointer on success, or ERR_PTR() on error.
1423 * Note: You probably want to use root_device_register().
1425 struct device *__root_device_register(const char *name, struct module *owner)
1427 struct root_device *root;
1430 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
1432 return ERR_PTR(err);
1434 err = dev_set_name(&root->dev, "%s", name);
1437 return ERR_PTR(err);
1440 root->dev.release = root_device_release;
1442 err = device_register(&root->dev);
1444 put_device(&root->dev);
1445 return ERR_PTR(err);
1448 #ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
1450 struct module_kobject *mk = &owner->mkobj;
1452 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
1454 device_unregister(&root->dev);
1455 return ERR_PTR(err);
1457 root->owner = owner;
1463 EXPORT_SYMBOL_GPL(__root_device_register);
1466 * root_device_unregister - unregister and free a root device
1467 * @dev: device going away
1469 * This function unregisters and cleans up a device that was created by
1470 * root_device_register().
1472 void root_device_unregister(struct device *dev)
1474 struct root_device *root = to_root_device(dev);
1477 sysfs_remove_link(&root->dev.kobj, "module");
1479 device_unregister(dev);
1481 EXPORT_SYMBOL_GPL(root_device_unregister);
1484 static void device_create_release(struct device *dev)
1486 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1491 * device_create_vargs - creates a device and registers it with sysfs
1492 * @class: pointer to the struct class that this device should be registered to
1493 * @parent: pointer to the parent struct device of this new device, if any
1494 * @devt: the dev_t for the char device to be added
1495 * @drvdata: the data to be added to the device for callbacks
1496 * @fmt: string for the device's name
1497 * @args: va_list for the device's name
1499 * This function can be used by char device classes. A struct device
1500 * will be created in sysfs, registered to the specified class.
1502 * A "dev" file will be created, showing the dev_t for the device, if
1503 * the dev_t is not 0,0.
1504 * If a pointer to a parent struct device is passed in, the newly created
1505 * struct device will be a child of that device in sysfs.
1506 * The pointer to the struct device will be returned from the call.
1507 * Any further sysfs files that might be required can be created using this
1510 * Returns &struct device pointer on success, or ERR_PTR() on error.
1512 * Note: the struct class passed to this function must have previously
1513 * been created with a call to class_create().
1515 struct device *device_create_vargs(struct class *class, struct device *parent,
1516 dev_t devt, void *drvdata, const char *fmt,
1519 struct device *dev = NULL;
1520 int retval = -ENODEV;
1522 if (class == NULL || IS_ERR(class))
1525 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1533 dev->parent = parent;
1534 dev->release = device_create_release;
1535 dev_set_drvdata(dev, drvdata);
1537 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
1541 retval = device_register(dev);
1549 return ERR_PTR(retval);
1551 EXPORT_SYMBOL_GPL(device_create_vargs);
1554 * device_create - creates a device and registers it with sysfs
1555 * @class: pointer to the struct class that this device should be registered to
1556 * @parent: pointer to the parent struct device of this new device, if any
1557 * @devt: the dev_t for the char device to be added
1558 * @drvdata: the data to be added to the device for callbacks
1559 * @fmt: string for the device's name
1561 * This function can be used by char device classes. A struct device
1562 * will be created in sysfs, registered to the specified class.
1564 * A "dev" file will be created, showing the dev_t for the device, if
1565 * the dev_t is not 0,0.
1566 * If a pointer to a parent struct device is passed in, the newly created
1567 * struct device will be a child of that device in sysfs.
1568 * The pointer to the struct device will be returned from the call.
1569 * Any further sysfs files that might be required can be created using this
1572 * Returns &struct device pointer on success, or ERR_PTR() on error.
1574 * Note: the struct class passed to this function must have previously
1575 * been created with a call to class_create().
1577 struct device *device_create(struct class *class, struct device *parent,
1578 dev_t devt, void *drvdata, const char *fmt, ...)
1583 va_start(vargs, fmt);
1584 dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
1588 EXPORT_SYMBOL_GPL(device_create);
1590 static int __match_devt(struct device *dev, void *data)
1594 return dev->devt == *devt;
1598 * device_destroy - removes a device that was created with device_create()
1599 * @class: pointer to the struct class that this device was registered with
1600 * @devt: the dev_t of the device that was previously registered
1602 * This call unregisters and cleans up a device that was created with a
1603 * call to device_create().
1605 void device_destroy(struct class *class, dev_t devt)
1609 dev = class_find_device(class, NULL, &devt, __match_devt);
1612 device_unregister(dev);
1615 EXPORT_SYMBOL_GPL(device_destroy);
1618 * device_rename - renames a device
1619 * @dev: the pointer to the struct device to be renamed
1620 * @new_name: the new name of the device
1622 * It is the responsibility of the caller to provide mutual
1623 * exclusion between two different calls of device_rename
1624 * on the same device to ensure that new_name is valid and
1625 * won't conflict with other devices.
1627 * Note: Don't call this function. Currently, the networking layer calls this
1628 * function, but that will change. The following text from Kay Sievers offers
1631 * Renaming devices is racy at many levels, symlinks and other stuff are not
1632 * replaced atomically, and you get a "move" uevent, but it's not easy to
1633 * connect the event to the old and new device. Device nodes are not renamed at
1634 * all, there isn't even support for that in the kernel now.
1636 * In the meantime, during renaming, your target name might be taken by another
1637 * driver, creating conflicts. Or the old name is taken directly after you
1638 * renamed it -- then you get events for the same DEVPATH, before you even see
1639 * the "move" event. It's just a mess, and nothing new should ever rely on
1640 * kernel device renaming. Besides that, it's not even implemented now for
1641 * other things than (driver-core wise very simple) network devices.
1643 * We are currently about to change network renaming in udev to completely
1644 * disallow renaming of devices in the same namespace as the kernel uses,
1645 * because we can't solve the problems properly, that arise with swapping names
1646 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
1647 * be allowed to some other name than eth[0-9]*, for the aforementioned
1650 * Make up a "real" name in the driver before you register anything, or add
1651 * some other attributes for userspace to find the device, or use udev to add
1652 * symlinks -- but never rename kernel devices later, it's a complete mess. We
1653 * don't even want to get into that and try to implement the missing pieces in
1654 * the core. We really have other pieces to fix in the driver core mess. :)
1656 int device_rename(struct device *dev, const char *new_name)
1658 char *old_class_name = NULL;
1659 char *new_class_name = NULL;
1660 char *old_device_name = NULL;
1663 dev = get_device(dev);
1667 pr_debug("device: '%s': %s: renaming to '%s'\n", dev_name(dev),
1668 __func__, new_name);
1670 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
1671 if (!old_device_name) {
1677 error = sysfs_rename_link(&dev->class->p->subsys.kobj,
1678 &dev->kobj, old_device_name, new_name);
1683 error = kobject_rename(&dev->kobj, new_name);
1690 kfree(new_class_name);
1691 kfree(old_class_name);
1692 kfree(old_device_name);
1696 EXPORT_SYMBOL_GPL(device_rename);
1698 static int device_move_class_links(struct device *dev,
1699 struct device *old_parent,
1700 struct device *new_parent)
1705 sysfs_remove_link(&dev->kobj, "device");
1707 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1713 * device_move - moves a device to a new parent
1714 * @dev: the pointer to the struct device to be moved
1715 * @new_parent: the new parent of the device (can by NULL)
1716 * @dpm_order: how to reorder the dpm_list
1718 int device_move(struct device *dev, struct device *new_parent,
1719 enum dpm_order dpm_order)
1722 struct device *old_parent;
1723 struct kobject *new_parent_kobj;
1725 dev = get_device(dev);
1730 new_parent = get_device(new_parent);
1731 new_parent_kobj = get_device_parent(dev, new_parent);
1733 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
1734 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
1735 error = kobject_move(&dev->kobj, new_parent_kobj);
1737 cleanup_glue_dir(dev, new_parent_kobj);
1738 put_device(new_parent);
1741 old_parent = dev->parent;
1742 dev->parent = new_parent;
1744 klist_remove(&dev->p->knode_parent);
1746 klist_add_tail(&dev->p->knode_parent,
1747 &new_parent->p->klist_children);
1748 set_dev_node(dev, dev_to_node(new_parent));
1753 error = device_move_class_links(dev, old_parent, new_parent);
1755 /* We ignore errors on cleanup since we're hosed anyway... */
1756 device_move_class_links(dev, new_parent, old_parent);
1757 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
1759 klist_remove(&dev->p->knode_parent);
1760 dev->parent = old_parent;
1762 klist_add_tail(&dev->p->knode_parent,
1763 &old_parent->p->klist_children);
1764 set_dev_node(dev, dev_to_node(old_parent));
1767 cleanup_glue_dir(dev, new_parent_kobj);
1768 put_device(new_parent);
1771 switch (dpm_order) {
1772 case DPM_ORDER_NONE:
1774 case DPM_ORDER_DEV_AFTER_PARENT:
1775 device_pm_move_after(dev, new_parent);
1777 case DPM_ORDER_PARENT_BEFORE_DEV:
1778 device_pm_move_before(new_parent, dev);
1780 case DPM_ORDER_DEV_LAST:
1781 device_pm_move_last(dev);
1785 put_device(old_parent);
1791 EXPORT_SYMBOL_GPL(device_move);
1794 * device_shutdown - call ->shutdown() on each device to shutdown.
1796 void device_shutdown(void)
1800 spin_lock(&devices_kset->list_lock);
1802 * Walk the devices list backward, shutting down each in turn.
1803 * Beware that device unplug events may also start pulling
1804 * devices offline, even as the system is shutting down.
1806 while (!list_empty(&devices_kset->list)) {
1807 dev = list_entry(devices_kset->list.prev, struct device,
1811 * Make sure the device is off the kset list, in the
1812 * event that dev->*->shutdown() doesn't remove it.
1814 list_del_init(&dev->kobj.entry);
1815 spin_unlock(&devices_kset->list_lock);
1817 /* Don't allow any more runtime suspends */
1818 pm_runtime_get_noresume(dev);
1819 pm_runtime_barrier(dev);
1821 if (dev->bus && dev->bus->shutdown) {
1822 dev_dbg(dev, "shutdown\n");
1823 dev->bus->shutdown(dev);
1824 } else if (dev->driver && dev->driver->shutdown) {
1825 dev_dbg(dev, "shutdown\n");
1826 dev->driver->shutdown(dev);
1830 spin_lock(&devices_kset->list_lock);
1832 spin_unlock(&devices_kset->list_lock);
1833 async_synchronize_full();
1837 * Device logging functions
1840 #ifdef CONFIG_PRINTK
1842 int __dev_printk(const char *level, const struct device *dev,
1843 struct va_format *vaf)
1846 return printk("%s(NULL device *): %pV", level, vaf);
1848 return printk("%s%s %s: %pV",
1849 level, dev_driver_string(dev), dev_name(dev), vaf);
1851 EXPORT_SYMBOL(__dev_printk);
1853 int dev_printk(const char *level, const struct device *dev,
1854 const char *fmt, ...)
1856 struct va_format vaf;
1860 va_start(args, fmt);
1865 r = __dev_printk(level, dev, &vaf);
1870 EXPORT_SYMBOL(dev_printk);
1872 #define define_dev_printk_level(func, kern_level) \
1873 int func(const struct device *dev, const char *fmt, ...) \
1875 struct va_format vaf; \
1879 va_start(args, fmt); \
1884 r = __dev_printk(kern_level, dev, &vaf); \
1889 EXPORT_SYMBOL(func);
1891 define_dev_printk_level(dev_emerg, KERN_EMERG);
1892 define_dev_printk_level(dev_alert, KERN_ALERT);
1893 define_dev_printk_level(dev_crit, KERN_CRIT);
1894 define_dev_printk_level(dev_err, KERN_ERR);
1895 define_dev_printk_level(dev_warn, KERN_WARNING);
1896 define_dev_printk_level(dev_notice, KERN_NOTICE);
1897 define_dev_printk_level(_dev_info, KERN_INFO);