/* * drivers/base/core.c - core driver model code (device registration, etc) * * Copyright (c) 2002-3 Patrick Mochel * Copyright (c) 2002-3 Open Source Development Labs * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de> * Copyright (c) 2006 Novell, Inc. * * This file is released under the GPLv2 * */ #include <linux/device.h> #include <linux/err.h> #include <linux/init.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/string.h> #include <linux/kdev_t.h> #include <linux/notifier.h> #include <linux/genhd.h> #include <linux/kallsyms.h> #include <linux/semaphore.h> #include <linux/mutex.h> #include <linux/async.h> #include "base.h" #include "power/power.h" int (*platform_notify)(struct device *dev) = NULL; int (*platform_notify_remove)(struct device *dev) = NULL; static struct kobject *dev_kobj; struct kobject *sysfs_dev_char_kobj; struct kobject *sysfs_dev_block_kobj; #ifdef CONFIG_BLOCK static inline int device_is_not_partition(struct device *dev) { return !(dev->type == &part_type); } #else static inline int device_is_not_partition(struct device *dev) { return 1; } #endif /** * dev_driver_string - Return a device's driver name, if at all possible * @dev: struct device to get the name of * * Will return the device's driver's name if it is bound to a device. If * the device is not bound to a device, it will return the name of the bus * it is attached to. If it is not attached to a bus either, an empty * string will be returned. */ const char *dev_driver_string(const struct device *dev) { struct device_driver *drv; /* dev->driver can change to NULL underneath us because of unbinding, * so be careful about accessing it. dev->bus and dev->class should * never change once they are set, so they don't need special care. */ drv = ACCESS_ONCE(dev->driver); return drv ? drv->name : (dev->bus ? dev->bus->name : (dev->class ? dev->class->name : "")); } EXPORT_SYMBOL(dev_driver_string); #define to_dev(obj) container_of(obj, struct device, kobj) #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr) static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { struct device_attribute *dev_attr = to_dev_attr(attr); struct device *dev = to_dev(kobj); ssize_t ret = -EIO; if (dev_attr->show) ret = dev_attr->show(dev, dev_attr, buf); if (ret >= (ssize_t)PAGE_SIZE) { print_symbol("dev_attr_show: %s returned bad count\n", (unsigned long)dev_attr->show); } return ret; } static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { struct device_attribute *dev_attr = to_dev_attr(attr); struct device *dev = to_dev(kobj); ssize_t ret = -EIO; if (dev_attr->store) ret = dev_attr->store(dev, dev_attr, buf, count); return ret; } static struct sysfs_ops dev_sysfs_ops = { .show = dev_attr_show, .store = dev_attr_store, }; /** * device_release - free device structure. * @kobj: device's kobject. * * This is called once the reference count for the object * reaches 0. We forward the call to the device's release * method, which should handle actually freeing the structure. */ static void device_release(struct kobject *kobj) { struct device *dev = to_dev(kobj); struct device_private *p = dev->p; if (dev->release) dev->release(dev); else if (dev->type && dev->type->release) dev->type->release(dev); else if (dev->class && dev->class->dev_release) dev->class->dev_release(dev); else WARN(1, KERN_ERR "Device '%s' does not have a release() " "function, it is broken and must be fixed.\n", dev_name(dev)); kfree(p); } static struct kobj_type device_ktype = { .release = device_release, .sysfs_ops = &dev_sysfs_ops, }; static int dev_uevent_filter(struct kset *kset, struct kobject *kobj) { struct kobj_type *ktype = get_ktype(kobj); if (ktype == &device_ktype) { struct device *dev = to_dev(kobj); if (dev->bus) return 1; if (dev->class) return 1; } return 0; } static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj) { struct device *dev = to_dev(kobj); if (dev->bus) return dev->bus->name; if (dev->class) return dev->class->name; return NULL; } static int dev_uevent(struct kset *kset, struct kobject *kobj, struct kobj_uevent_env *env) { struct device *dev = to_dev(kobj); int retval = 0; /* add device node properties if present */ if (MAJOR(dev->devt)) { const char *tmp; const char *name; mode_t mode = 0; add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt)); add_uevent_var(env, "MINOR=%u", MINOR(dev->devt)); name = device_get_devnode(dev, &mode, &tmp); if (name) { add_uevent_var(env, "DEVNAME=%s", name); kfree(tmp); if (mode) add_uevent_var(env, "DEVMODE=%#o", mode & 0777); } } if (dev->type && dev->type->name) add_uevent_var(env, "DEVTYPE=%s", dev->type->name); if (dev->driver) add_uevent_var(env, "DRIVER=%s", dev->driver->name); #ifdef CONFIG_SYSFS_DEPRECATED if (dev->class) { struct device *parent = dev->parent; /* find first bus device in parent chain */ while (parent && !parent->bus) parent = parent->parent; if (parent && parent->bus) { const char *path; path = kobject_get_path(&parent->kobj, GFP_KERNEL); if (path) { add_uevent_var(env, "PHYSDEVPATH=%s", path); kfree(path); } add_uevent_var(env, "PHYSDEVBUS=%s", parent->bus->name); if (parent->driver) add_uevent_var(env, "PHYSDEVDRIVER=%s", parent->driver->name); } } else if (dev->bus) { add_uevent_var(env, "PHYSDEVBUS=%s", dev->bus->name); if (dev->driver) add_uevent_var(env, "PHYSDEVDRIVER=%s", dev->driver->name); } #endif /* have the bus specific function add its stuff */ if (dev->bus && dev->bus->uevent) { retval = dev->bus->uevent(dev, env); if (retval) pr_debug("device: '%s': %s: bus uevent() returned %d\n", dev_name(dev), __func__, retval); } /* have the class specific function add its stuff */ if (dev->class && dev->class->dev_uevent) { retval = dev->class->dev_uevent(dev, env); if (retval) pr_debug("device: '%s': %s: class uevent() " "returned %d\n", dev_name(dev), __func__, retval); } /* have the device type specific fuction add its stuff */ if (dev->type && dev->type->uevent) { retval = dev->type->uevent(dev, env); if (retval) pr_debug("device: '%s': %s: dev_type uevent() " "returned %d\n", dev_name(dev), __func__, retval); } return retval; } static struct kset_uevent_ops device_uevent_ops = { .filter = dev_uevent_filter, .name = dev_uevent_name, .uevent = dev_uevent, }; static ssize_t show_uevent(struct device *dev, struct device_attribute *attr, char *buf) { struct kobject *top_kobj; struct kset *kset; struct kobj_uevent_env *env = NULL; int i; size_t count = 0; int retval; /* search the kset, the device belongs to */ top_kobj = &dev->kobj; while (!top_kobj->kset && top_kobj->parent) top_kobj = top_kobj->parent; if (!top_kobj->kset) goto out; kset = top_kobj->kset; if (!kset->uevent_ops || !kset->uevent_ops->uevent) goto out; /* respect filter */ if (kset->uevent_ops && kset->uevent_ops->filter) if (!kset->uevent_ops->filter(kset, &dev->kobj)) goto out; env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); if (!env) return -ENOMEM; /* let the kset specific function add its keys */ retval = kset->uevent_ops->uevent(kset, &dev->kobj, env); if (retval) goto out; /* copy keys to file */ for (i = 0; i < env->envp_idx; i++) count += sprintf(&buf[count], "%s\n", env->envp[i]); out: kfree(env); return count; } static ssize_t store_uevent(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { enum kobject_action action; if (kobject_action_type(buf, count, &action) == 0) { kobject_uevent(&dev->kobj, action); goto out; } dev_err(dev, "uevent: unsupported action-string; this will " "be ignored in a future kernel version\n"); kobject_uevent(&dev->kobj, KOBJ_ADD); out: return count; } static struct device_attribute uevent_attr = __ATTR(uevent, S_IRUGO | S_IWUSR, show_uevent, store_uevent); static int device_add_attributes(struct device *dev, struct device_attribute *attrs) { int error = 0; int i; if (attrs) { for (i = 0; attr_name(attrs[i]); i++) { error = device_create_file(dev, &attrs[i]); if (error) break; } if (error) while (--i >= 0) device_remove_file(dev, &attrs[i]); } return error; } static void device_remove_attributes(struct device *dev, struct device_attribute *attrs) { int i; if (attrs) for (i = 0; attr_name(attrs[i]); i++) device_remove_file(dev, &attrs[i]); } static int device_add_groups(struct device *dev, const struct attribute_group **groups) { int error = 0; int i; if (groups) { for (i = 0; groups[i]; i++) { error = sysfs_create_group(&dev->kobj, groups[i]); if (error) { while (--i >= 0) sysfs_remove_group(&dev->kobj, groups[i]); break; } } } return error; } static void device_remove_groups(struct device *dev, const struct attribute_group **groups) { int i; if (groups) for (i = 0; groups[i]; i++) sysfs_remove_group(&dev->kobj, groups[i]); } static int device_add_attrs(struct device *dev) { struct class *class = dev->class; struct device_type *type = dev->type; int error; if (class) { error = device_add_attributes(dev, class->dev_attrs); if (error) return error; } if (type) { error = device_add_groups(dev, type->groups); if (error) goto err_remove_class_attrs; } error = device_add_groups(dev, dev->groups); if (error) goto err_remove_type_groups; return 0; err_remove_type_groups: if (type) device_remove_groups(dev, type->groups); err_remove_class_attrs: if (class) device_remove_attributes(dev, class->dev_attrs); return error; } static void device_remove_attrs(struct device *dev) { struct class *class = dev->class; struct device_type *type = dev->type; device_remove_groups(dev, dev->groups); if (type) device_remove_groups(dev, type->groups); if (class) device_remove_attributes(dev, class->dev_attrs); } static ssize_t show_dev(struct device *dev, struct device_attribute *attr, char *buf) { return print_dev_t(buf, dev->devt); } static struct device_attribute devt_attr = __ATTR(dev, S_IRUGO, show_dev, NULL); /* kset to create /sys/devices/ */ struct kset *devices_kset; /** * device_create_file - create sysfs attribute file for device. * @dev: device. * @attr: device attribute descriptor. */ int device_create_file(struct device *dev, const struct device_attribute *attr) { int error = 0; if (dev) error = sysfs_create_file(&dev->kobj, &attr->attr); return error; } /** * device_remove_file - remove sysfs attribute file. * @dev: device. * @attr: device attribute descriptor. */ void device_remove_file(struct device *dev, const struct device_attribute *attr) { if (dev) sysfs_remove_file(&dev->kobj, &attr->attr); } /** * device_create_bin_file - create sysfs binary attribute file for device. * @dev: device. * @attr: device binary attribute descriptor. */ int device_create_bin_file(struct device *dev, const struct bin_attribute *attr) { int error = -EINVAL; if (dev) error = sysfs_create_bin_file(&dev->kobj, attr); return error; } EXPORT_SYMBOL_GPL(device_create_bin_file); /** * device_remove_bin_file - remove sysfs binary attribute file * @dev: device. * @attr: device binary attribute descriptor. */ void device_remove_bin_file(struct device *dev, const struct bin_attribute *attr) { if (dev) sysfs_remove_bin_file(&dev->kobj, attr); } EXPORT_SYMBOL_GPL(device_remove_bin_file); /** * device_schedule_callback_owner - helper to schedule a callback for a device * @dev: device. * @func: callback function to invoke later. * @owner: module owning the callback routine * * Attribute methods must not unregister themselves or their parent device * (which would amount to the same thing). Attempts to do so will deadlock, * since unregistration is mutually exclusive with driver callbacks. * * Instead methods can call this routine, which will attempt to allocate * and schedule a workqueue request to call back @func with @dev as its * argument in the workqueue's process context. @dev will be pinned until * @func returns. * * This routine is usually called via the inline device_schedule_callback(), * which automatically sets @owner to THIS_MODULE. * * Returns 0 if the request was submitted, -ENOMEM if storage could not * be allocated, -ENODEV if a reference to @owner isn't available. * * NOTE: This routine won't work if CONFIG_SYSFS isn't set! It uses an * underlying sysfs routine (since it is intended for use by attribute * methods), and if sysfs isn't available you'll get nothing but -ENOSYS. */ int device_schedule_callback_owner(struct device *dev, void (*func)(struct device *), struct module *owner) { return sysfs_schedule_callback(&dev->kobj, (void (*)(void *)) func, dev, owner); } EXPORT_SYMBOL_GPL(device_schedule_callback_owner); static void klist_children_get(struct klist_node *n) { struct device_private *p = to_device_private_parent(n); struct device *dev = p->device; get_device(dev); } static void klist_children_put(struct klist_node *n) { struct device_private *p = to_device_private_parent(n); struct device *dev = p->device; put_device(dev); } /** * device_initialize - init device structure. * @dev: device. * * This prepares the device for use by other layers by initializing * its fields. * It is the first half of device_register(), if called by * that function, though it can also be called separately, so one * may use @dev's fields. In particular, get_device()/put_device() * may be used for reference counting of @dev after calling this * function. * * NOTE: Use put_device() to give up your reference instead of freeing * @dev directly once you have called this function. */ void device_initialize(struct device *dev) { dev->kobj.kset = devices_kset; kobject_init(&dev->kobj, &device_ktype); INIT_LIST_HEAD(&dev->dma_pools); init_MUTEX(&dev->sem); spin_lock_init(&dev->devres_lock); INIT_LIST_HEAD(&dev->devres_head); device_init_wakeup(dev, 0); device_pm_init(dev); set_dev_node(dev, -1); } #ifdef CONFIG_SYSFS_DEPRECATED static struct kobject *get_device_parent(struct device *dev, struct device *parent) { /* class devices without a parent live in /sys/class/<classname>/ */ if (dev->class && (!parent || parent->class != dev->class)) return &dev->class->p->class_subsys.kobj; /* all other devices keep their parent */ else if (parent) return &parent->kobj; return NULL; } static inline void cleanup_device_parent(struct device *dev) {} static inline void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir) {} #else static struct kobject *virtual_device_parent(struct device *dev) { static struct kobject *virtual_dir = NULL; if (!virtual_dir) virtual_dir = kobject_create_and_add("virtual", &devices_kset->kobj); return virtual_dir; } static struct kobject *get_device_parent(struct device *dev, struct device *parent) { int retval; if (dev->class) { struct kobject *kobj = NULL; struct kobject *parent_kobj; struct kobject *k; /* * If we have no parent, we live in "virtual". * Class-devices with a non class-device as parent, live * in a "glue" directory to prevent namespace collisions. */ if (parent == NULL) parent_kobj = virtual_device_parent(dev); else if (parent->class) return &parent->kobj; else parent_kobj = &parent->kobj; /* find our class-directory at the parent and reference it */ spin_lock(&dev->class->p->class_dirs.list_lock); list_for_each_entry(k, &dev->class->p->class_dirs.list, entry) if (k->parent == parent_kobj) { kobj = kobject_get(k); break; } spin_unlock(&dev->class->p->class_dirs.list_lock); if (kobj) return kobj; /* or create a new class-directory at the parent device */ k = kobject_create(); if (!k) return NULL; k->kset = &dev->class->p->class_dirs; retval = kobject_add(k, parent_kobj, "%s", dev->class->name); if (retval < 0) { kobject_put(k); return NULL; } /* do not emit an uevent for this simple "glue" directory */ return k; } if (parent) return &parent->kobj; return NULL; } static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir) { /* see if we live in a "glue" directory */ if (!glue_dir || !dev->class || glue_dir->kset != &dev->class->p->class_dirs) return; kobject_put(glue_dir); } static void cleanup_device_parent(struct device *dev) { cleanup_glue_dir(dev, dev->kobj.parent); } #endif static void setup_parent(struct device *dev, struct device *parent) { struct kobject *kobj; kobj = get_device_parent(dev, parent); if (kobj) dev->kobj.parent = kobj; } static int device_add_class_symlinks(struct device *dev) { int error; if (!dev->class) return 0; error = sysfs_create_link(&dev->kobj, &dev->class->p->class_subsys.kobj, "subsystem"); if (error) goto out; #ifdef CONFIG_SYSFS_DEPRECATED /* stacked class devices need a symlink in the class directory */ if (dev->kobj.parent != &dev->class->p->class_subsys.kobj && device_is_not_partition(dev)) { error = sysfs_create_link(&dev->class->p->class_subsys.kobj, &dev->kobj, dev_name(dev)); if (error) goto out_subsys; } if (dev->parent && device_is_not_partition(dev)) { struct device *parent = dev->parent; char *class_name; /* * stacked class devices have the 'device' link * pointing to the bus device instead of the parent */ while (parent->class && !parent->bus && parent->parent) parent = parent->parent; error = sysfs_create_link(&dev->kobj, &parent->kobj, "device"); if (error) goto out_busid; class_name = make_class_name(dev->class->name, &dev->kobj); if (class_name) error = sysfs_create_link(&dev->parent->kobj, &dev->kobj, class_name); kfree(class_name); if (error) goto out_device; } return 0; out_device: if (dev->parent && device_is_not_partition(dev)) sysfs_remove_link(&dev->kobj, "device"); out_busid: if (dev->kobj.parent != &dev->class->p->class_subsys.kobj && device_is_not_partition(dev)) sysfs_remove_link(&dev->class->p->class_subsys.kobj, dev_name(dev)); #else /* link in the class directory pointing to the device */ error = sysfs_create_link(&dev->class->p->class_subsys.kobj, &dev->kobj, dev_name(dev)); if (error) goto out_subsys; if (dev->parent && device_is_not_partition(dev)) { error = sysfs_create_link(&dev->kobj, &dev->parent->kobj, "device"); if (error) goto out_busid; } return 0; out_busid: sysfs_remove_link(&dev->class->p->class_subsys.kobj, dev_name(dev)); #endif out_subsys: sysfs_remove_link(&dev->kobj, "subsystem"); out: return error; } static void device_remove_class_symlinks(struct device *dev) { if (!dev->class) return; #ifdef CONFIG_SYSFS_DEPRECATED if (dev->parent && device_is_not_partition(dev)) { char *class_name; class_name = make_class_name(dev->class->name, &dev->kobj); if (class_name) { sysfs_remove_link(&dev->parent->kobj, class_name); kfree(class_name); } sysfs_remove_link(&dev->kobj, "device"); } if (dev->kobj.parent != &dev->class->p->class_subsys.kobj && device_is_not_partition(dev)) sysfs_remove_link(&dev->class->p->class_subsys.kobj, dev_name(dev)); #else if (dev->parent && device_is_not_partition(dev)) sysfs_remove_link(&dev->kobj, "device"); sysfs_remove_link(&dev->class->p->class_subsys.kobj, dev_name(dev)); #endif sysfs_remove_link(&dev->kobj, "subsystem"); } /** * dev_set_name - set a device name * @dev: device * @fmt: format string for the device's name */ int dev_set_name(struct device *dev, const char *fmt, ...) { va_list vargs; int err; va_start(vargs, fmt); err = kobject_set_name_vargs(&dev->kobj, fmt, vargs); va_end(vargs); return err; } EXPORT_SYMBOL_GPL(dev_set_name); /** * device_to_dev_kobj - select a /sys/dev/ directory for the device * @dev: device * * By default we select char/ for new entries. Setting class->dev_obj * to NULL prevents an entry from being created. class->dev_kobj must * be set (or cleared) before any devices are registered to the class * otherwise device_create_sys_dev_entry() and * device_remove_sys_dev_entry() will disagree about the the presence * of the link. */ static struct kobject *device_to_dev_kobj(struct device *dev) { struct kobject *kobj; if (dev->class) kobj = dev->class->dev_kobj; else kobj = sysfs_dev_char_kobj; return kobj; } static int device_create_sys_dev_entry(struct device *dev) { struct kobject *kobj = device_to_dev_kobj(dev); int error = 0; char devt_str[15]; if (kobj) { format_dev_t(devt_str, dev->devt); error = sysfs_create_link(kobj, &dev->kobj, devt_str); } return error; } static void device_remove_sys_dev_entry(struct device *dev) { struct kobject *kobj = device_to_dev_kobj(dev); char devt_str[15]; if (kobj) { format_dev_t(devt_str, dev->devt); sysfs_remove_link(kobj, devt_str); } } int device_private_init(struct device *dev) { dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL); if (!dev->p) return -ENOMEM; dev->p->device = dev; klist_init(&dev->p->klist_children, klist_children_get, klist_children_put); return 0; } /** * device_add - add device to device hierarchy. * @dev: device. * * This is part 2 of device_register(), though may be called * separately _iff_ device_initialize() has been called separately. * * This adds @dev to the kobject hierarchy via kobject_add(), adds it * to the global and sibling lists for the device, then * adds it to the other relevant subsystems of the driver model. * * NOTE: _Never_ directly free @dev after calling this function, even * if it returned an error! Always use put_device() to give up your * reference instead. */ int device_add(struct device *dev) { struct device *parent = NULL; struct class_interface *class_intf; int error = -EINVAL; dev = get_device(dev); if (!dev) goto done; if (!dev->p) { error = device_private_init(dev); if (error) goto done; } /* * for statically allocated devices, which should all be converted * some day, we need to initialize the name. We prevent reading back * the name, and force the use of dev_name() */ if (dev->init_name) { dev_set_name(dev, "%s", dev->init_name); dev->init_name = NULL; } if (!dev_name(dev)) { error = -EINVAL; goto name_error; } pr_debug("device: '%s': %s\n", dev_name(dev), __func__); parent = get_device(dev->parent); setup_parent(dev, parent); /* use parent numa_node */ if (parent) set_dev_node(dev, dev_to_node(parent)); /* first, register with generic layer. */ /* we require the name to be set before, and pass NULL */ error = kobject_add(&dev->kobj, dev->kobj.parent, NULL); if (error) goto Error; /* notify platform of device entry */ if (platform_notify) platform_notify(dev); error = device_create_file(dev, &uevent_attr); if (error) goto attrError; if (MAJOR(dev->devt)) { error = device_create_file(dev, &devt_attr); if (error) goto ueventattrError; error = device_create_sys_dev_entry(dev); if (error) goto devtattrError; devtmpfs_create_node(dev); } error = device_add_class_symlinks(dev); if (error) goto SymlinkError; error = device_add_attrs(dev); if (error) goto AttrsError; error = bus_add_device(dev); if (error) goto BusError; error = dpm_sysfs_add(dev); if (error) goto DPMError; device_pm_add(dev); /* Notify clients of device addition. This call must come * after dpm_sysf_add() and before kobject_uevent(). */ if (dev->bus) blocking_notifier_call_chain(&dev->bus->p->bus_notifier, BUS_NOTIFY_ADD_DEVICE, dev); kobject_uevent(&dev->kobj, KOBJ_ADD); bus_probe_device(dev); if (parent) klist_add_tail(&dev->p->knode_parent, &parent->p->klist_children); if (dev->class) { mutex_lock(&dev->class->p->class_mutex); /* tie the class to the device */ klist_add_tail(&dev->knode_class, &dev->class->p->class_devices); /* notify any interfaces that the device is here */ list_for_each_entry(class_intf, &dev->class->p->class_interfaces, node) if (class_intf->add_dev) class_intf->add_dev(dev, class_intf); mutex_unlock(&dev->class->p->class_mutex); } done: put_device(dev); return error; DPMError: bus_remove_device(dev); BusError: device_remove_attrs(dev); AttrsError: device_remove_class_symlinks(dev); SymlinkError: if (MAJOR(dev->devt)) devtmpfs_delete_node(dev); if (MAJOR(dev->devt)) device_remove_sys_dev_entry(dev); devtattrError: if (MAJOR(dev->devt)) device_remove_file(dev, &devt_attr); ueventattrError: device_remove_file(dev, &uevent_attr); attrError: kobject_uevent(&dev->kobj, KOBJ_REMOVE); kobject_del(&dev->kobj); Error: cleanup_device_parent(dev); if (parent) put_device(parent); name_error: kfree(dev->p); dev->p = NULL; goto done; } /** * device_register - register a device with the system. * @dev: pointer to the device structure * * This happens in two clean steps - initialize the device * and add it to the system. The two steps can be called * separately, but this is the easiest and most common. * I.e. you should only call the two helpers separately if * have a clearly defined need to use and refcount the device * before it is added to the hierarchy. * * NOTE: _Never_ directly free @dev after calling this function, even * if it returned an error! Always use put_device() to give up the * reference initialized in this function instead. */ int device_register(struct device *dev) { device_initialize(dev); return device_add(dev); } /** * get_device - increment reference count for device. * @dev: device. * * This simply forwards the call to kobject_get(), though * we do take care to provide for the case that we get a NULL * pointer passed in. */ struct device *get_device(struct device *dev) { return dev ? to_dev(kobject_get(&dev->kobj)) : NULL; } /** * put_device - decrement reference count. * @dev: device in question. */ void put_device(struct device *dev) { /* might_sleep(); */ if (dev) kobject_put(&dev->kobj); } /** * device_del - delete device from system. * @dev: device. * * This is the first part of the device unregistration * sequence. This removes the device from the lists we control * from here, has it removed from the other driver model * subsystems it was added to in device_add(), and removes it * from the kobject hierarchy. * * NOTE: this should be called manually _iff_ device_add() was * also called manually. */ void device_del(struct device *dev) { struct device *parent = dev->parent; struct class_interface *class_intf; /* Notify clients of device removal. This call must come * before dpm_sysfs_remove(). */ if (dev->bus) blocking_notifier_call_chain(&dev->bus->p->bus_notifier, BUS_NOTIFY_DEL_DEVICE, dev); device_pm_remove(dev); dpm_sysfs_remove(dev); if (parent) klist_del(&dev->p->knode_parent); if (MAJOR(dev->devt)) { devtmpfs_delete_node(dev); device_remove_sys_dev_entry(dev); device_remove_file(dev, &devt_attr); } if (dev->class) { device_remove_class_symlinks(dev); mutex_lock(&dev->class->p->class_mutex); /* notify any interfaces that the device is now gone */ list_for_each_entry(class_intf, &dev->class->p->class_interfaces, node) if (class_intf->remove_dev) class_intf->remove_dev(dev, class_intf); /* remove the device from the class list */ klist_del(&dev->knode_class); mutex_unlock(&dev->class->p->class_mutex); } device_remove_file(dev, &uevent_attr); device_remove_attrs(dev); bus_remove_device(dev); /* * Some platform devices are driven without driver attached * and managed resources may have been acquired. Make sure * all resources are released. */ devres_release_all(dev); /* Notify the platform of the removal, in case they * need to do anything... */ if (platform_notify_remove) platform_notify_remove(dev); kobject_uevent(&dev->kobj, KOBJ_REMOVE); cleanup_device_parent(dev); kobject_del(&dev->kobj); put_device(parent); } /** * device_unregister - unregister device from system. * @dev: device going away. * * We do this in two parts, like we do device_register(). First, * we remove it from all the subsystems with device_del(), then * we decrement the reference count via put_device(). If that * is the final reference count, the device will be cleaned up * via device_release() above. Otherwise, the structure will * stick around until the final reference to the device is dropped. */ void device_unregister(struct device *dev) { pr_debug("device: '%s': %s\n", dev_name(dev), __func__); device_del(dev); put_device(dev); } static struct device *next_device(struct klist_iter *i) { struct klist_node *n = klist_next(i); struct device *dev = NULL; struct device_private *p; if (n) { p = to_device_private_parent(n); dev = p->device; } return dev; } /** * device_get_devnode - path of device node file * @dev: device * @mode: returned file access mode * @tmp: possibly allocated string * * Return the relative path of a possible device node. * Non-default names may need to allocate a memory to compose * a name. This memory is returned in tmp and needs to be * freed by the caller. */ const char *device_get_devnode(struct device *dev, mode_t *mode, const char **tmp) { char *s; *tmp = NULL; /* the device type may provide a specific name */ if (dev->type && dev->type->devnode) *tmp = dev->type->devnode(dev, mode); if (*tmp) return *tmp; /* the class may provide a specific name */ if (dev->class && dev->class->devnode) *tmp = dev->class->devnode(dev, mode); if (*tmp) return *tmp; /* return name without allocation, tmp == NULL */ if (strchr(dev_name(dev), '!') == NULL) return dev_name(dev); /* replace '!' in the name with '/' */ *tmp = kstrdup(dev_name(dev), GFP_KERNEL); if (!*tmp) return NULL; while ((s = strchr(*tmp, '!'))) s[0] = '/'; return *tmp; } /** * device_for_each_child - device child iterator. * @parent: parent struct device. * @data: data for the callback. * @fn: function to be called for each device. * * Iterate over @parent's child devices, and call @fn for each, * passing it @data. * * We check the return of @fn each time. If it returns anything * other than 0, we break out and return that value. */ int device_for_each_child(struct device *parent, void *data, int (*fn)(struct device *dev, void *data)) { struct klist_iter i; struct device *child; int error = 0; if (!parent->p) return 0; klist_iter_init(&parent->p->klist_children, &i); while ((child = next_device(&i)) && !error) error = fn(child, data); klist_iter_exit(&i); return error; } /** * device_find_child - device iterator for locating a particular device. * @parent: parent struct device * @data: Data to pass to match function * @match: Callback function to check device * * This is similar to the device_for_each_child() function above, but it * returns a reference to a device that is 'found' for later use, as * determined by the @match callback. * * The callback should return 0 if the device doesn't match and non-zero * if it does. If the callback returns non-zero and a reference to the * current device can be obtained, this function will return to the caller * and not iterate over any more devices. */ struct device *device_find_child(struct device *parent, void *data, int (*match)(struct device *dev, void *data)) { struct klist_iter i; struct device *child; if (!parent) return NULL; klist_iter_init(&parent->p->klist_children, &i); while ((child = next_device(&i))) if (match(child, data) && get_device(child)) break; klist_iter_exit(&i); return child; } int __init devices_init(void) { devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL); if (!devices_kset) return -ENOMEM; dev_kobj = kobject_create_and_add("dev", NULL); if (!dev_kobj) goto dev_kobj_err; sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj); if (!sysfs_dev_block_kobj) goto block_kobj_err; sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj); if (!sysfs_dev_char_kobj) goto char_kobj_err; return 0; char_kobj_err: kobject_put(sysfs_dev_block_kobj); block_kobj_err: kobject_put(dev_kobj); dev_kobj_err: kset_unregister(devices_kset); return -ENOMEM; } EXPORT_SYMBOL_GPL(device_for_each_child); EXPORT_SYMBOL_GPL(device_find_child); EXPORT_SYMBOL_GPL(device_initialize); EXPORT_SYMBOL_GPL(device_add); EXPORT_SYMBOL_GPL(device_register); EXPORT_SYMBOL_GPL(device_del); EXPORT_SYMBOL_GPL(device_unregister); EXPORT_SYMBOL_GPL(get_device); EXPORT_SYMBOL_GPL(put_device); EXPORT_SYMBOL_GPL(device_create_file); EXPORT_SYMBOL_GPL(device_remove_file); struct root_device { struct device dev; struct module *owner; }; #define to_root_device(dev) container_of(dev, struct root_device, dev) static void root_device_release(struct device *dev) { kfree(to_root_device(dev)); } /** * __root_device_register - allocate and register a root device * @name: root device name * @owner: owner module of the root device, usually THIS_MODULE * * This function allocates a root device and registers it * using device_register(). In order to free the returned * device, use root_device_unregister(). * * Root devices are dummy devices which allow other devices * to be grouped under /sys/devices. Use this function to * allocate a root device and then use it as the parent of * any device which should appear under /sys/devices/{name} * * The /sys/devices/{name} directory will also contain a * 'module' symlink which points to the @owner directory * in sysfs. * * Note: You probably want to use root_device_register(). */ struct device *__root_device_register(const char *name, struct module *owner) { struct root_device *root; int err = -ENOMEM; root = kzalloc(sizeof(struct root_device), GFP_KERNEL); if (!root) return ERR_PTR(err); err = dev_set_name(&root->dev, "%s", name); if (err) { kfree(root); return ERR_PTR(err); } root->dev.release = root_device_release; err = device_register(&root->dev); if (err) { put_device(&root->dev); return ERR_PTR(err); } #ifdef CONFIG_MODULE /* gotta find a "cleaner" way to do this */ if (owner) { struct module_kobject *mk = &owner->mkobj; err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module"); if (err) { device_unregister(&root->dev); return ERR_PTR(err); } root->owner = owner; } #endif return &root->dev; } EXPORT_SYMBOL_GPL(__root_device_register); /** * root_device_unregister - unregister and free a root device * @dev: device going away * * This function unregisters and cleans up a device that was created by * root_device_register(). */ void root_device_unregister(struct device *dev) { struct root_device *root = to_root_device(dev); if (root->owner) sysfs_remove_link(&root->dev.kobj, "module"); device_unregister(dev); } EXPORT_SYMBOL_GPL(root_device_unregister); static void device_create_release(struct device *dev) { pr_debug("device: '%s': %s\n", dev_name(dev), __func__); kfree(dev); } /** * device_create_vargs - creates a device and registers it with sysfs * @class: pointer to the struct class that this device should be registered to * @parent: pointer to the parent struct device of this new device, if any * @devt: the dev_t for the char device to be added * @drvdata: the data to be added to the device for callbacks * @fmt: string for the device's name * @args: va_list for the device's name * * This function can be used by char device classes. A struct device * will be created in sysfs, registered to the specified class. * * A "dev" file will be created, showing the dev_t for the device, if * the dev_t is not 0,0. * If a pointer to a parent struct device is passed in, the newly created * struct device will be a child of that device in sysfs. * The pointer to the struct device will be returned from the call. * Any further sysfs files that might be required can be created using this * pointer. * * Note: the struct class passed to this function must have previously * been created with a call to class_create(). */ struct device *device_create_vargs(struct class *class, struct device *parent, dev_t devt, void *drvdata, const char *fmt, va_list args) { struct device *dev = NULL; int retval = -ENODEV; if (class == NULL || IS_ERR(class)) goto error; dev = kzalloc(sizeof(*dev), GFP_KERNEL); if (!dev) { retval = -ENOMEM; goto error; } dev->devt = devt; dev->class = class; dev->parent = parent; dev->release = device_create_release; dev_set_drvdata(dev, drvdata); retval = kobject_set_name_vargs(&dev->kobj, fmt, args); if (retval) goto error; retval = device_register(dev); if (retval) goto error; return dev; error: put_device(dev); return ERR_PTR(retval); } EXPORT_SYMBOL_GPL(device_create_vargs); /** * device_create - creates a device and registers it with sysfs * @class: pointer to the struct class that this device should be registered to * @parent: pointer to the parent struct device of this new device, if any * @devt: the dev_t for the char device to be added * @drvdata: the data to be added to the device for callbacks * @fmt: string for the device's name * * This function can be used by char device classes. A struct device * will be created in sysfs, registered to the specified class. * * A "dev" file will be created, showing the dev_t for the device, if * the dev_t is not 0,0. * If a pointer to a parent struct device is passed in, the newly created * struct device will be a child of that device in sysfs. * The pointer to the struct device will be returned from the call. * Any further sysfs files that might be required can be created using this * pointer. * * Note: the struct class passed to this function must have previously * been created with a call to class_create(). */ struct device *device_create(struct class *class, struct device *parent, dev_t devt, void *drvdata, const char *fmt, ...) { va_list vargs; struct device *dev; va_start(vargs, fmt); dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs); va_end(vargs); return dev; } EXPORT_SYMBOL_GPL(device_create); static int __match_devt(struct device *dev, void *data) { dev_t *devt = data; return dev->devt == *devt; } /** * device_destroy - removes a device that was created with device_create() * @class: pointer to the struct class that this device was registered with * @devt: the dev_t of the device that was previously registered * * This call unregisters and cleans up a device that was created with a * call to device_create(). */ void device_destroy(struct class *class, dev_t devt) { struct device *dev; dev = class_find_device(class, NULL, &devt, __match_devt); if (dev) { put_device(dev); device_unregister(dev); } } EXPORT_SYMBOL_GPL(device_destroy); /** * device_rename - renames a device * @dev: the pointer to the struct device to be renamed * @new_name: the new name of the device * * It is the responsibility of the caller to provide mutual * exclusion between two different calls of device_rename * on the same device to ensure that new_name is valid and * won't conflict with other devices. */ int device_rename(struct device *dev, char *new_name) { char *old_class_name = NULL; char *new_class_name = NULL; char *old_device_name = NULL; int error; dev = get_device(dev); if (!dev) return -EINVAL; pr_debug("device: '%s': %s: renaming to '%s'\n", dev_name(dev), __func__, new_name); #ifdef CONFIG_SYSFS_DEPRECATED if ((dev->class) && (dev->parent)) old_class_name = make_class_name(dev->class->name, &dev->kobj); #endif old_device_name = kstrdup(dev_name(dev), GFP_KERNEL); if (!old_device_name) { error = -ENOMEM; goto out; } error = kobject_rename(&dev->kobj, new_name); if (error) goto out; #ifdef CONFIG_SYSFS_DEPRECATED if (old_class_name) { new_class_name = make_class_name(dev->class->name, &dev->kobj); if (new_class_name) { error = sysfs_create_link_nowarn(&dev->parent->kobj, &dev->kobj, new_class_name); if (error) goto out; sysfs_remove_link(&dev->parent->kobj, old_class_name); } } #else if (dev->class) { error = sysfs_create_link_nowarn(&dev->class->p->class_subsys.kobj, &dev->kobj, dev_name(dev)); if (error) goto out; sysfs_remove_link(&dev->class->p->class_subsys.kobj, old_device_name); } #endif out: put_device(dev); kfree(new_class_name); kfree(old_class_name); kfree(old_device_name); return error; } EXPORT_SYMBOL_GPL(device_rename); static int device_move_class_links(struct device *dev, struct device *old_parent, struct device *new_parent) { int error = 0; #ifdef CONFIG_SYSFS_DEPRECATED char *class_name; class_name = make_class_name(dev->class->name, &dev->kobj); if (!class_name) { error = -ENOMEM; goto out; } if (old_parent) { sysfs_remove_link(&dev->kobj, "device"); sysfs_remove_link(&old_parent->kobj, class_name); } if (new_parent) { error = sysfs_create_link(&dev->kobj, &new_parent->kobj, "device"); if (error) goto out; error = sysfs_create_link(&new_parent->kobj, &dev->kobj, class_name); if (error) sysfs_remove_link(&dev->kobj, "device"); } else error = 0; out: kfree(class_name); return error; #else if (old_parent) sysfs_remove_link(&dev->kobj, "device"); if (new_parent) error = sysfs_create_link(&dev->kobj, &new_parent->kobj, "device"); return error; #endif } /** * device_move - moves a device to a new parent * @dev: the pointer to the struct device to be moved * @new_parent: the new parent of the device (can by NULL) * @dpm_order: how to reorder the dpm_list */ int device_move(struct device *dev, struct device *new_parent, enum dpm_order dpm_order) { int error; struct device *old_parent; struct kobject *new_parent_kobj; dev = get_device(dev); if (!dev) return -EINVAL; device_pm_lock(); new_parent = get_device(new_parent); new_parent_kobj = get_device_parent(dev, new_parent); pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev), __func__, new_parent ? dev_name(new_parent) : "<NULL>"); error = kobject_move(&dev->kobj, new_parent_kobj); if (error) { cleanup_glue_dir(dev, new_parent_kobj); put_device(new_parent); goto out; } old_parent = dev->parent; dev->parent = new_parent; if (old_parent) klist_remove(&dev->p->knode_parent); if (new_parent) { klist_add_tail(&dev->p->knode_parent, &new_parent->p->klist_children); set_dev_node(dev, dev_to_node(new_parent)); } if (!dev->class) goto out_put; error = device_move_class_links(dev, old_parent, new_parent); if (error) { /* We ignore errors on cleanup since we're hosed anyway... */ device_move_class_links(dev, new_parent, old_parent); if (!kobject_move(&dev->kobj, &old_parent->kobj)) { if (new_parent) klist_remove(&dev->p->knode_parent); dev->parent = old_parent; if (old_parent) { klist_add_tail(&dev->p->knode_parent, &old_parent->p->klist_children); set_dev_node(dev, dev_to_node(old_parent)); } } cleanup_glue_dir(dev, new_parent_kobj); put_device(new_parent); goto out; } switch (dpm_order) { case DPM_ORDER_NONE: break; case DPM_ORDER_DEV_AFTER_PARENT: device_pm_move_after(dev, new_parent); break; case DPM_ORDER_PARENT_BEFORE_DEV: device_pm_move_before(new_parent, dev); break; case DPM_ORDER_DEV_LAST: device_pm_move_last(dev); break; } out_put: put_device(old_parent); out: device_pm_unlock(); put_device(dev); return error; } EXPORT_SYMBOL_GPL(device_move); /** * device_shutdown - call ->shutdown() on each device to shutdown. */ void device_shutdown(void) { struct device *dev, *devn; list_for_each_entry_safe_reverse(dev, devn, &devices_kset->list, kobj.entry) { if (dev->bus && dev->bus->shutdown) { dev_dbg(dev, "shutdown\n"); dev->bus->shutdown(dev); } else if (dev->driver && dev->driver->shutdown) { dev_dbg(dev, "shutdown\n"); dev->driver->shutdown(dev); } } async_synchronize_full(); }