/* * class.c - basic device class management * * Copyright (c) 2002-3 Patrick Mochel * Copyright (c) 2002-3 Open Source Development Labs * Copyright (c) 2003-2004 Greg Kroah-Hartman * Copyright (c) 2003-2004 IBM Corp. * * This file is released under the GPLv2 * */ #include <linux/device.h> #include <linux/module.h> #include <linux/init.h> #include <linux/string.h> #include <linux/kdev_t.h> #include <linux/err.h> #include <linux/slab.h> #include <linux/genhd.h> #include <linux/mutex.h> #include "base.h" #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr) static ssize_t class_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { struct class_attribute *class_attr = to_class_attr(attr); struct class_private *cp = to_class(kobj); ssize_t ret = -EIO; if (class_attr->show) ret = class_attr->show(cp->class, buf); return ret; } static ssize_t class_attr_store(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { struct class_attribute *class_attr = to_class_attr(attr); struct class_private *cp = to_class(kobj); ssize_t ret = -EIO; if (class_attr->store) ret = class_attr->store(cp->class, buf, count); return ret; } static void class_release(struct kobject *kobj) { struct class_private *cp = to_class(kobj); struct class *class = cp->class; pr_debug("class '%s': release.\n", class->name); if (class->class_release) class->class_release(class); else pr_debug("class '%s' does not have a release() function, " "be careful\n", class->name); } static struct sysfs_ops class_sysfs_ops = { .show = class_attr_show, .store = class_attr_store, }; static struct kobj_type class_ktype = { .sysfs_ops = &class_sysfs_ops, .release = class_release, }; /* Hotplug events for classes go to the class class_subsys */ static struct kset *class_kset; int class_create_file(struct class *cls, const struct class_attribute *attr) { int error; if (cls) error = sysfs_create_file(&cls->p->class_subsys.kobj, &attr->attr); else error = -EINVAL; return error; } void class_remove_file(struct class *cls, const struct class_attribute *attr) { if (cls) sysfs_remove_file(&cls->p->class_subsys.kobj, &attr->attr); } static struct class *class_get(struct class *cls) { if (cls) kset_get(&cls->p->class_subsys); return cls; } static void class_put(struct class *cls) { if (cls) kset_put(&cls->p->class_subsys); } static int add_class_attrs(struct class *cls) { int i; int error = 0; if (cls->class_attrs) { for (i = 0; attr_name(cls->class_attrs[i]); i++) { error = class_create_file(cls, &cls->class_attrs[i]); if (error) goto error; } } done: return error; error: while (--i >= 0) class_remove_file(cls, &cls->class_attrs[i]); goto done; } static void remove_class_attrs(struct class *cls) { int i; if (cls->class_attrs) { for (i = 0; attr_name(cls->class_attrs[i]); i++) class_remove_file(cls, &cls->class_attrs[i]); } } int __class_register(struct class *cls, struct lock_class_key *key) { struct class_private *cp; int error; pr_debug("device class '%s': registering\n", cls->name); cp = kzalloc(sizeof(*cp), GFP_KERNEL); if (!cp) return -ENOMEM; INIT_LIST_HEAD(&cp->class_devices); INIT_LIST_HEAD(&cp->class_interfaces); kset_init(&cp->class_dirs); __mutex_init(&cp->class_mutex, "struct class mutex", key); error = kobject_set_name(&cp->class_subsys.kobj, "%s", cls->name); if (error) { kfree(cp); return error; } /* set the default /sys/dev directory for devices of this class */ if (!cls->dev_kobj) cls->dev_kobj = sysfs_dev_char_kobj; #if defined(CONFIG_SYSFS_DEPRECATED) && defined(CONFIG_BLOCK) /* let the block class directory show up in the root of sysfs */ if (cls != &block_class) cp->class_subsys.kobj.kset = class_kset; #else cp->class_subsys.kobj.kset = class_kset; #endif cp->class_subsys.kobj.ktype = &class_ktype; cp->class = cls; cls->p = cp; error = kset_register(&cp->class_subsys); if (error) { kfree(cp); return error; } error = add_class_attrs(class_get(cls)); class_put(cls); return error; } EXPORT_SYMBOL_GPL(__class_register); void class_unregister(struct class *cls) { pr_debug("device class '%s': unregistering\n", cls->name); remove_class_attrs(cls); kset_unregister(&cls->p->class_subsys); } static void class_create_release(struct class *cls) { pr_debug("%s called for %s\n", __func__, cls->name); kfree(cls); } /** * class_create - create a struct class structure * @owner: pointer to the module that is to "own" this struct class * @name: pointer to a string for the name of this class. * * This is used to create a struct class pointer that can then be used * in calls to device_create(). * * Note, the pointer created here is to be destroyed when finished by * making a call to class_destroy(). */ struct class *__class_create(struct module *owner, const char *name, struct lock_class_key *key) { struct class *cls; int retval; cls = kzalloc(sizeof(*cls), GFP_KERNEL); if (!cls) { retval = -ENOMEM; goto error; } cls->name = name; cls->owner = owner; cls->class_release = class_create_release; retval = __class_register(cls, key); if (retval) goto error; return cls; error: kfree(cls); return ERR_PTR(retval); } EXPORT_SYMBOL_GPL(__class_create); /** * class_destroy - destroys a struct class structure * @cls: pointer to the struct class that is to be destroyed * * Note, the pointer to be destroyed must have been created with a call * to class_create(). */ void class_destroy(struct class *cls) { if ((cls == NULL) || (IS_ERR(cls))) return; class_unregister(cls); } #ifdef CONFIG_SYSFS_DEPRECATED char *make_class_name(const char *name, struct kobject *kobj) { char *class_name; int size; size = strlen(name) + strlen(kobject_name(kobj)) + 2; class_name = kmalloc(size, GFP_KERNEL); if (!class_name) return NULL; strcpy(class_name, name); strcat(class_name, ":"); strcat(class_name, kobject_name(kobj)); return class_name; } #endif /** * class_for_each_device - device iterator * @class: the class we're iterating * @start: the device to start with in the list, if any. * @data: data for the callback * @fn: function to be called for each device * * Iterate over @class's list of devices, and call @fn for each, * passing it @data. If @start is set, the list iteration will start * there, otherwise if it is NULL, the iteration starts at the * beginning of the list. * * We check the return of @fn each time. If it returns anything * other than 0, we break out and return that value. * * Note, we hold class->class_mutex in this function, so it can not be * re-acquired in @fn, otherwise it will self-deadlocking. For * example, calls to add or remove class members would be verboten. */ int class_for_each_device(struct class *class, struct device *start, void *data, int (*fn)(struct device *, void *)) { struct device *dev; int error = 0; if (!class) return -EINVAL; mutex_lock(&class->p->class_mutex); list_for_each_entry(dev, &class->p->class_devices, node) { if (start) { if (start == dev) start = NULL; continue; } dev = get_device(dev); error = fn(dev, data); put_device(dev); if (error) break; } mutex_unlock(&class->p->class_mutex); return error; } EXPORT_SYMBOL_GPL(class_for_each_device); /** * class_find_device - device iterator for locating a particular device * @class: the class we're iterating * @start: Device to begin with * @data: data for the match function * @match: function to check device * * This is similar to the class_for_each_dev() 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, this function will * return to the caller and not iterate over any more devices. * * Note, you will need to drop the reference with put_device() after use. * * We hold class->class_mutex in this function, so it can not be * re-acquired in @match, otherwise it will self-deadlocking. For * example, calls to add or remove class members would be verboten. */ struct device *class_find_device(struct class *class, struct device *start, void *data, int (*match)(struct device *, void *)) { struct device *dev; int found = 0; if (!class) return NULL; mutex_lock(&class->p->class_mutex); list_for_each_entry(dev, &class->p->class_devices, node) { if (start) { if (start == dev) start = NULL; continue; } dev = get_device(dev); if (match(dev, data)) { found = 1; break; } else put_device(dev); } mutex_unlock(&class->p->class_mutex); return found ? dev : NULL; } EXPORT_SYMBOL_GPL(class_find_device); int class_interface_register(struct class_interface *class_intf) { struct class *parent; struct device *dev; if (!class_intf || !class_intf->class) return -ENODEV; parent = class_get(class_intf->class); if (!parent) return -EINVAL; mutex_lock(&parent->p->class_mutex); list_add_tail(&class_intf->node, &parent->p->class_interfaces); if (class_intf->add_dev) { list_for_each_entry(dev, &parent->p->class_devices, node) class_intf->add_dev(dev, class_intf); } mutex_unlock(&parent->p->class_mutex); return 0; } void class_interface_unregister(struct class_interface *class_intf) { struct class *parent = class_intf->class; struct device *dev; if (!parent) return; mutex_lock(&parent->p->class_mutex); list_del_init(&class_intf->node); if (class_intf->remove_dev) { list_for_each_entry(dev, &parent->p->class_devices, node) class_intf->remove_dev(dev, class_intf); } mutex_unlock(&parent->p->class_mutex); class_put(parent); } int __init classes_init(void) { class_kset = kset_create_and_add("class", NULL, NULL); if (!class_kset) return -ENOMEM; return 0; } EXPORT_SYMBOL_GPL(class_create_file); EXPORT_SYMBOL_GPL(class_remove_file); EXPORT_SYMBOL_GPL(class_unregister); EXPORT_SYMBOL_GPL(class_destroy); EXPORT_SYMBOL_GPL(class_interface_register); EXPORT_SYMBOL_GPL(class_interface_unregister);