/* * 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 <asm/semaphore.h> #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 : ""); } EXPORT_SYMBOL_GPL(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->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 ktype_device = { .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 == &ktype_device) { 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, char **envp, int num_envp, char *buffer, int buffer_size) { struct device *dev = to_dev(kobj); int i = 0; int length = 0; int retval = 0; /* add the major/minor if present */ if (MAJOR(dev->devt)) { add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length, "MAJOR=%u", MAJOR(dev->devt)); add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length, "MINOR=%u", MINOR(dev->devt)); } /* add bus name (same as SUBSYSTEM, deprecated) */ if (dev->bus) add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length, "PHYSDEVBUS=%s", dev->bus->name); /* add driver name (PHYSDEV* values are deprecated)*/ if (dev->driver) { add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length, "DRIVER=%s", dev->driver->name); add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length, "PHYSDEVDRIVER=%s", dev->driver->name); } /* terminate, set to next free slot, shrink available space */ envp[i] = NULL; envp = &envp[i]; num_envp -= i; buffer = &buffer[length]; buffer_size -= length; if (dev->bus && dev->bus->uevent) { /* have the bus specific function add its stuff */ retval = dev->bus->uevent(dev, envp, num_envp, buffer, buffer_size); if (retval) { pr_debug ("%s - uevent() returned %d\n", __FUNCTION__, retval); } } if (dev->class && dev->class->dev_uevent) { /* have the class specific function add its stuff */ retval = dev->class->dev_uevent(dev, envp, num_envp, buffer, buffer_size); if (retval) { pr_debug("%s - dev_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 store_uevent(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { kobject_uevent(&dev->kobj, KOBJ_ADD); return count; } static int device_add_groups(struct device *dev) { int i; int error = 0; if (dev->groups) { for (i = 0; dev->groups[i]; i++) { error = sysfs_create_group(&dev->kobj, dev->groups[i]); if (error) { while (--i >= 0) sysfs_remove_group(&dev->kobj, dev->groups[i]); goto out; } } } out: return error; } static void device_remove_groups(struct device *dev) { int i; if (dev->groups) { for (i = 0; dev->groups[i]; i++) { sysfs_remove_group(&dev->kobj, dev->groups[i]); } } } static int device_add_attrs(struct device *dev) { struct class *class = dev->class; int error = 0; int i; if (!class) return 0; if (class->dev_attrs) { for (i = 0; attr_name(class->dev_attrs[i]); i++) { error = device_create_file(dev, &class->dev_attrs[i]); if (error) break; } } if (error) while (--i >= 0) device_remove_file(dev, &class->dev_attrs[i]); return error; } static void device_remove_attrs(struct device *dev) { struct class *class = dev->class; int i; if (!class) return; if (class->dev_attrs) { for (i = 0; attr_name(class->dev_attrs[i]); i++) device_remove_file(dev, &class->dev_attrs[i]); } } static ssize_t show_dev(struct device *dev, struct device_attribute *attr, char *buf) { return print_dev_t(buf, dev->devt); } /* * devices_subsys - structure to be registered with kobject core. */ decl_subsys(devices, &ktype_device, &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); 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) { kobj_set_kset_s(dev, devices_subsys); 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); device_init_wakeup(dev, 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 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; char *class_name = NULL; struct class_interface *class_intf; int error = -EINVAL; dev = get_device(dev); if (!dev || !strlen(dev->bus_id)) goto Error; /* if this is a class device, and has no parent, create one */ if ((dev->class) && (dev->parent == NULL)) { error = virtual_device_parent(dev); if (error) goto Error; } parent = get_device(dev->parent); pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id); /* first, register with generic layer. */ kobject_set_name(&dev->kobj, "%s", dev->bus_id); if (parent) dev->kobj.parent = &parent->kobj; if ((error = kobject_add(&dev->kobj))) goto Error; /* notify platform of device entry */ if (platform_notify) platform_notify(dev); dev->uevent_attr.attr.name = "uevent"; dev->uevent_attr.attr.mode = S_IWUSR; if (dev->driver) dev->uevent_attr.attr.owner = dev->driver->owner; dev->uevent_attr.store = store_uevent; device_create_file(dev, &dev->uevent_attr); if (MAJOR(dev->devt)) { struct device_attribute *attr; attr = kzalloc(sizeof(*attr), GFP_KERNEL); if (!attr) { error = -ENOMEM; goto PMError; } attr->attr.name = "dev"; attr->attr.mode = S_IRUGO; if (dev->driver) attr->attr.owner = dev->driver->owner; attr->show = show_dev; error = device_create_file(dev, attr); if (error) { kfree(attr); goto attrError; } dev->devt_attr = attr; } if (dev->class) { sysfs_create_link(&dev->kobj, &dev->class->subsys.kset.kobj, "subsystem"); sysfs_create_link(&dev->class->subsys.kset.kobj, &dev->kobj, dev->bus_id); if (parent) { sysfs_create_link(&dev->kobj, &dev->parent->kobj, "device"); class_name = make_class_name(dev->class->name, &dev->kobj); sysfs_create_link(&dev->parent->kobj, &dev->kobj, class_name); } } if ((error = device_add_attrs(dev))) goto AttrsError; if ((error = device_add_groups(dev))) goto GroupError; if ((error = device_pm_add(dev))) goto PMError; if ((error = bus_add_device(dev))) 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: kfree(class_name); put_device(dev); return error; BusError: device_pm_remove(dev); PMError: device_remove_groups(dev); GroupError: device_remove_attrs(dev); AttrsError: if (dev->devt_attr) { device_remove_file(dev, dev->devt_attr); kfree(dev->devt_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; char *class_name = NULL; struct class_interface *class_intf; if (parent) klist_del(&dev->knode_parent); if (dev->devt_attr) device_remove_file(dev, dev->devt_attr); if (dev->class) { sysfs_remove_link(&dev->kobj, "subsystem"); sysfs_remove_link(&dev->class->subsys.kset.kobj, dev->bus_id); class_name = make_class_name(dev->class->name, &dev->kobj); if (parent) { sysfs_remove_link(&dev->kobj, "device"); sysfs_remove_link(&dev->parent->kobj, class_name); } kfree(class_name); 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); } device_remove_file(dev, &dev->uevent_attr); device_remove_groups(dev); device_remove_attrs(dev); /* Notify the platform of the removal, in case they * need to do anything... */ if (platform_notify_remove) platform_notify_remove(dev); bus_remove_device(dev); device_pm_remove(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; } int __init devices_init(void) { return subsystem_register(&devices_subsys); } EXPORT_SYMBOL_GPL(device_for_each_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); /** * 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 = 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); if (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 */ int device_rename(struct device *dev, char *new_name) { char *old_class_name = NULL; char *new_class_name = NULL; char *old_symlink_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); if ((dev->class) && (dev->parent)) old_class_name = make_class_name(dev->class->name, &dev->kobj); if (dev->class) { old_symlink_name = kmalloc(BUS_ID_SIZE, GFP_KERNEL); if (!old_symlink_name) return -ENOMEM; strlcpy(old_symlink_name, dev->bus_id, BUS_ID_SIZE); } strlcpy(dev->bus_id, new_name, BUS_ID_SIZE); error = kobject_rename(&dev->kobj, new_name); if (old_class_name) { new_class_name = make_class_name(dev->class->name, &dev->kobj); if (new_class_name) { sysfs_create_link(&dev->parent->kobj, &dev->kobj, new_class_name); sysfs_remove_link(&dev->parent->kobj, old_class_name); } } if (dev->class) { sysfs_remove_link(&dev->class->subsys.kset.kobj, old_symlink_name); sysfs_create_link(&dev->class->subsys.kset.kobj, &dev->kobj, dev->bus_id); } put_device(dev); kfree(old_class_name); kfree(new_class_name); kfree(old_symlink_name); return error; }