/* * 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 * Copyright (c) 2006 Novell, Inc. * * This file is released under the GPLv2 * */ #include #include #include #include #include #include #include #include #include #include "base.h" #include "power/power.h" int (*platform_notify)(struct device * dev) = NULL; int (*platform_notify_remove)(struct device * dev) = NULL; /* * sysfs bindings for devices. */ /** * 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(struct device *dev) { return dev->driver ? dev->driver->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); 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); 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 { printk(KERN_ERR "Device '%s' does not have a release() function, " "it is broken and must be fixed.\n", dev->bus_id); WARN_ON(1); } } 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->uevent_suppress) return 0; 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 the major/minor if present */ if (MAJOR(dev->devt)) { add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt)); add_uevent_var(env, "MINOR=%u", MINOR(dev->devt)); } 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 ("%s: bus uevent() returned %d\n", __FUNCTION__, 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("%s: class uevent() returned %d\n", __FUNCTION__, 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("%s: dev_type uevent() returned %d\n", __FUNCTION__, 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, 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, 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); /* * devices_subsys - structure to be registered with kobject core. */ decl_subsys(devices, &device_uevent_ops); /** * device_create_file - create sysfs attribute file for device. * @dev: device. * @attr: device attribute descriptor. */ int device_create_file(struct device * dev, struct device_attribute * attr) { int error = 0; if (get_device(dev)) { error = sysfs_create_file(&dev->kobj, &attr->attr); put_device(dev); } return error; } /** * device_remove_file - remove sysfs attribute file. * @dev: device. * @attr: device attribute descriptor. */ void device_remove_file(struct device * dev, struct device_attribute * attr) { if (get_device(dev)) { sysfs_remove_file(&dev->kobj, &attr->attr); put_device(dev); } } /** * 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, 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, 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 *dev = container_of(n, struct device, knode_parent); get_device(dev); } static void klist_children_put(struct klist_node *n) { struct device *dev = container_of(n, struct device, knode_parent); put_device(dev); } /** * device_initialize - init device structure. * @dev: device. * * This prepares the device for use by other layers, * including adding it to the device hierarchy. * It is the first half of device_register(), if called by * that, though it can also be called separately, so one * may use @dev's fields (e.g. the refcount). */ void device_initialize(struct device *dev) { dev->kobj.kset = &devices_subsys; dev->kobj.ktype = &device_ktype; kobject_init(&dev->kobj); klist_init(&dev->klist_children, klist_children_get, klist_children_put); INIT_LIST_HEAD(&dev->dma_pools); INIT_LIST_HEAD(&dev->node); init_MUTEX(&dev->sem); spin_lock_init(&dev->devres_lock); INIT_LIST_HEAD(&dev->devres_head); device_init_wakeup(dev, 0); set_dev_node(dev, -1); } #ifdef CONFIG_SYSFS_DEPRECATED static struct kobject * get_device_parent(struct device *dev, struct device *parent) { /* * Set the parent to the class, not the parent device * for topmost devices in class hierarchy. * This keeps sysfs from having a symlink to make old * udevs happy */ if (dev->class && (!parent || parent->class != dev->class)) return &dev->class->subsys.kobj; else if (parent) return &parent->kobj; return NULL; } #else static struct kobject *virtual_device_parent(struct device *dev) { static struct kobject *virtual_dir = NULL; if (!virtual_dir) virtual_dir = kobject_add_dir(&devices_subsys.kobj, "virtual"); return virtual_dir; } static struct kobject * get_device_parent(struct device *dev, struct device *parent) { 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 bus-device as parent, live * in a class-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->class_dirs.list_lock); list_for_each_entry(k, &dev->class->class_dirs.list, entry) if (k->parent == parent_kobj) { kobj = kobject_get(k); break; } spin_unlock(&dev->class->class_dirs.list_lock); if (kobj) return kobj; /* or create a new class-directory at the parent device */ return kobject_kset_add_dir(&dev->class->class_dirs, parent_kobj, dev->class->name); } if (parent) return &parent->kobj; return NULL; } #endif static int setup_parent(struct device *dev, struct device *parent) { struct kobject *kobj; kobj = get_device_parent(dev, parent); if (IS_ERR(kobj)) return PTR_ERR(kobj); if (kobj) dev->kobj.parent = kobj; return 0; } static int device_add_class_symlinks(struct device *dev) { int error; if (!dev->class) return 0; error = sysfs_create_link(&dev->kobj, &dev->class->subsys.kobj, "subsystem"); if (error) goto out; /* * If this is not a "fake" compatible device, then create the * symlink from the class to the device. */ if (dev->kobj.parent != &dev->class->subsys.kobj) { error = sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj, dev->bus_id); if (error) goto out_subsys; } if (dev->parent) { #ifdef CONFIG_SYSFS_DEPRECATED { struct device *parent = dev->parent; char *class_name; /* * In old sysfs stacked class devices had 'device' * link pointing to real device instead of 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; } #else error = sysfs_create_link(&dev->kobj, &dev->parent->kobj, "device"); if (error) goto out_busid; #endif } return 0; #ifdef CONFIG_SYSFS_DEPRECATED out_device: if (dev->parent) sysfs_remove_link(&dev->kobj, "device"); #endif out_busid: if (dev->kobj.parent != &dev->class->subsys.kobj) sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id); out_subsys: sysfs_remove_link(&dev->kobj, "subsystem"); out: return error; } static void device_remove_class_symlinks(struct device *dev) { if (!dev->class) return; if (dev->parent) { #ifdef CONFIG_SYSFS_DEPRECATED 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); } #endif sysfs_remove_link(&dev->kobj, "device"); } if (dev->kobj.parent != &dev->class->subsys.kobj) sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id); sysfs_remove_link(&dev->kobj, "subsystem"); } /** * 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 it 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. */ int device_add(struct device *dev) { struct device *parent = NULL; struct class_interface *class_intf; int error; error = pm_sleep_lock(); if (error) { dev_warn(dev, "Suspicious %s during suspend\n", __FUNCTION__); dump_stack(); return error; } dev = get_device(dev); if (!dev || !strlen(dev->bus_id)) { error = -EINVAL; goto Error; } pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id); parent = get_device(dev->parent); error = setup_parent(dev, parent); if (error) goto Error; /* first, register with generic layer. */ kobject_set_name(&dev->kobj, "%s", dev->bus_id); error = kobject_add(&dev->kobj); if (error) goto Error; /* notify platform of device entry */ if (platform_notify) platform_notify(dev); /* notify clients of device entry (new way) */ if (dev->bus) blocking_notifier_call_chain(&dev->bus->bus_notifier, BUS_NOTIFY_ADD_DEVICE, 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_add_class_symlinks(dev); if (error) goto SymlinkError; error = device_add_attrs(dev); if (error) goto AttrsError; error = dpm_sysfs_add(dev); if (error) goto PMError; device_pm_add(dev); error = bus_add_device(dev); if (error) goto BusError; kobject_uevent(&dev->kobj, KOBJ_ADD); bus_attach_device(dev); if (parent) klist_add_tail(&dev->knode_parent, &parent->klist_children); if (dev->class) { down(&dev->class->sem); /* tie the class to the device */ list_add_tail(&dev->node, &dev->class->devices); /* notify any interfaces that the device is here */ list_for_each_entry(class_intf, &dev->class->interfaces, node) if (class_intf->add_dev) class_intf->add_dev(dev, class_intf); up(&dev->class->sem); } Done: put_device(dev); pm_sleep_unlock(); return error; BusError: device_pm_remove(dev); dpm_sysfs_remove(dev); PMError: if (dev->bus) blocking_notifier_call_chain(&dev->bus->bus_notifier, BUS_NOTIFY_DEL_DEVICE, dev); device_remove_attrs(dev); AttrsError: device_remove_class_symlinks(dev); SymlinkError: if (MAJOR(dev->devt)) device_remove_file(dev, &devt_attr); if (dev->class) { sysfs_remove_link(&dev->kobj, "subsystem"); /* If this is not a "fake" compatible device, remove the * symlink from the class to the device. */ if (dev->kobj.parent != &dev->class->subsys.kobj) sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id); if (parent) { #ifdef CONFIG_SYSFS_DEPRECATED char *class_name = make_class_name(dev->class->name, &dev->kobj); if (class_name) sysfs_remove_link(&dev->parent->kobj, class_name); kfree(class_name); #endif sysfs_remove_link(&dev->kobj, "device"); } } ueventattrError: device_remove_file(dev, &uevent_attr); attrError: kobject_uevent(&dev->kobj, KOBJ_REMOVE); kobject_del(&dev->kobj); Error: if (parent) put_device(parent); 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. */ 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) { 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; device_pm_remove(dev); if (parent) klist_del(&dev->knode_parent); if (MAJOR(dev->devt)) device_remove_file(dev, &devt_attr); if (dev->class) { sysfs_remove_link(&dev->kobj, "subsystem"); /* If this is not a "fake" compatible device, remove the * symlink from the class to the device. */ if (dev->kobj.parent != &dev->class->subsys.kobj) sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id); if (parent) { #ifdef CONFIG_SYSFS_DEPRECATED char *class_name = make_class_name(dev->class->name, &dev->kobj); if (class_name) sysfs_remove_link(&dev->parent->kobj, class_name); kfree(class_name); #endif sysfs_remove_link(&dev->kobj, "device"); } down(&dev->class->sem); /* notify any interfaces that the device is now gone */ list_for_each_entry(class_intf, &dev->class->interfaces, node) if (class_intf->remove_dev) class_intf->remove_dev(dev, class_intf); /* remove the device from the class list */ list_del_init(&dev->node); up(&dev->class->sem); /* If we live in a parent class-directory, unreference it */ if (dev->kobj.parent->kset == &dev->class->class_dirs) { struct device *d; int other = 0; /* * if we are the last child of our class, delete * our class-directory at this parent */ down(&dev->class->sem); list_for_each_entry(d, &dev->class->devices, node) { if (d == dev) continue; if (d->kobj.parent == dev->kobj.parent) { other = 1; break; } } if (!other) kobject_del(dev->kobj.parent); kobject_put(dev->kobj.parent); up(&dev->class->sem); } } 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); if (dev->bus) blocking_notifier_call_chain(&dev->bus->bus_notifier, BUS_NOTIFY_DEL_DEVICE, dev); kobject_uevent(&dev->kobj, KOBJ_REMOVE); kobject_del(&dev->kobj); if (parent) 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("DEV: Unregistering device. ID = '%s'\n", dev->bus_id); device_del(dev); put_device(dev); } static struct device * next_device(struct klist_iter * i) { struct klist_node * n = klist_next(i); return n ? container_of(n, struct device, knode_parent) : NULL; } /** * 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 *, void *)) { struct klist_iter i; struct device * child; int error = 0; klist_iter_init(&parent->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 *, void *)) { struct klist_iter i; struct device *child; if (!parent) return NULL; klist_iter_init(&parent->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) { return subsystem_register(&devices_subsys); } 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); static void device_create_release(struct device *dev) { pr_debug("%s called for %s\n", __FUNCTION__, dev->bus_id); kfree(dev); } /** * 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 * @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, 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; va_start(args, fmt); vsnprintf(dev->bus_id, BUS_ID_SIZE, fmt, args); va_end(args); retval = device_register(dev); if (retval) goto error; return dev; error: kfree(dev); return ERR_PTR(retval); } EXPORT_SYMBOL_GPL(device_create); /** * find_device - finds 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 */ static struct device *find_device(struct class *class, dev_t devt) { struct device *dev = NULL; struct device *dev_tmp; down(&class->sem); list_for_each_entry(dev_tmp, &class->devices, node) { if (dev_tmp->devt == devt) { dev = dev_tmp; break; } } up(&class->sem); return dev; } /** * 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 = find_device(class, devt); if (dev) device_unregister(dev); } EXPORT_SYMBOL_GPL(device_destroy); #ifdef CONFIG_PM_SLEEP /** * destroy_suspended_device - asks the PM core to remove a suspended device * @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 notifies the PM core of the necessity to unregister a suspended * device created with a call to device_create() (devices cannot be * unregistered directly while suspended, since the PM core holds their * semaphores at that time). * * It can only be called within the scope of a system sleep transition. In * practice this means it has to be directly or indirectly invoked either by * a suspend or resume method, or by the PM core (e.g. via * disable_nonboot_cpus() or enable_nonboot_cpus()). */ void destroy_suspended_device(struct class *class, dev_t devt) { struct device *dev; dev = find_device(class, devt); if (dev) device_pm_schedule_removal(dev); } EXPORT_SYMBOL_GPL(destroy_suspended_device); #endif /* CONFIG_PM_SLEEP */ /** * device_rename - renames a device * @dev: the pointer to the struct device to be renamed * @new_name: the new name of the device */ 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: renaming '%s' to '%s'\n", dev->bus_id, 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 = kmalloc(BUS_ID_SIZE, GFP_KERNEL); if (!old_device_name) { error = -ENOMEM; goto out; } strlcpy(old_device_name, dev->bus_id, BUS_ID_SIZE); strlcpy(dev->bus_id, new_name, BUS_ID_SIZE); error = kobject_rename(&dev->kobj, new_name); if (error) { strlcpy(dev->bus_id, old_device_name, BUS_ID_SIZE); 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(&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) { sysfs_remove_link(&dev->class->subsys.kobj, old_device_name); error = sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj, dev->bus_id); if (error) { dev_err(dev, "%s: sysfs_create_symlink failed (%d)\n", __FUNCTION__, error); } } #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) */ int device_move(struct device *dev, struct device *new_parent) { int error; struct device *old_parent; struct kobject *new_parent_kobj; dev = get_device(dev); if (!dev) return -EINVAL; new_parent = get_device(new_parent); new_parent_kobj = get_device_parent (dev, new_parent); if (IS_ERR(new_parent_kobj)) { error = PTR_ERR(new_parent_kobj); put_device(new_parent); goto out; } pr_debug("DEVICE: moving '%s' to '%s'\n", dev->bus_id, new_parent ? new_parent->bus_id : ""); error = kobject_move(&dev->kobj, new_parent_kobj); if (error) { put_device(new_parent); goto out; } old_parent = dev->parent; dev->parent = new_parent; if (old_parent) klist_remove(&dev->knode_parent); if (new_parent) klist_add_tail(&dev->knode_parent, &new_parent->klist_children); 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->knode_parent); if (old_parent) klist_add_tail(&dev->knode_parent, &old_parent->klist_children); } put_device(new_parent); goto out; } out_put: put_device(old_parent); out: put_device(dev); return error; } EXPORT_SYMBOL_GPL(device_move);