/* * 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 "base.h" #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr) #define to_class(obj) container_of(obj, struct class, subsys.kobj) 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 *dc = to_class(kobj); ssize_t ret = -EIO; if (class_attr->show) ret = class_attr->show(dc, 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 *dc = to_class(kobj); ssize_t ret = -EIO; if (class_attr->store) ret = class_attr->store(dc, buf, count); return ret; } static void class_release(struct kobject *kobj) { struct class *class = to_class(kobj); 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_obj 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->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->subsys.kobj, &attr->attr); } static struct class *class_get(struct class *cls) { if (cls) return container_of(kset_get(&cls->subsys), struct class, subsys); return NULL; } static void class_put(struct class *cls) { if (cls) kset_put(&cls->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) { int error; pr_debug("device class '%s': registering\n", cls->name); INIT_LIST_HEAD(&cls->children); INIT_LIST_HEAD(&cls->devices); INIT_LIST_HEAD(&cls->interfaces); kset_init(&cls->class_dirs); init_MUTEX(&cls->sem); error = kobject_set_name(&cls->subsys.kobj, "%s", cls->name); if (error) return error; #if defined(CONFIG_SYSFS_DEPRECATED) && defined(CONFIG_BLOCK) /* let the block class directory show up in the root of sysfs */ if (cls != &block_class) cls->subsys.kobj.kset = class_kset; #else cls->subsys.kobj.kset = class_kset; #endif cls->subsys.kobj.ktype = &class_ktype; error = kset_register(&cls->subsys); if (!error) { error = add_class_attrs(class_get(cls)); class_put(cls); } return error; } void class_unregister(struct class *cls) { pr_debug("device class '%s': unregistering\n", cls->name); remove_class_attrs(cls); kset_unregister(&cls->subsys); } static void class_create_release(struct class *cls) { pr_debug("%s called for %s\n", __FUNCTION__, cls->name); kfree(cls); } static void class_device_create_release(struct class_device *class_dev) { pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id); kfree(class_dev); } /* needed to allow these devices to have parent class devices */ static int class_device_create_uevent(struct class_device *class_dev, struct kobj_uevent_env *env) { pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id); return 0; } /** * 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 class_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 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; cls->release = class_device_create_release; retval = class_register(cls); if (retval) goto error; return cls; error: kfree(cls); return ERR_PTR(retval); } /** * 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); } /* Class Device Stuff */ int class_device_create_file(struct class_device *class_dev, const struct class_device_attribute *attr) { int error = -EINVAL; if (class_dev) error = sysfs_create_file(&class_dev->kobj, &attr->attr); return error; } void class_device_remove_file(struct class_device *class_dev, const struct class_device_attribute *attr) { if (class_dev) sysfs_remove_file(&class_dev->kobj, &attr->attr); } int class_device_create_bin_file(struct class_device *class_dev, struct bin_attribute *attr) { int error = -EINVAL; if (class_dev) error = sysfs_create_bin_file(&class_dev->kobj, attr); return error; } void class_device_remove_bin_file(struct class_device *class_dev, struct bin_attribute *attr) { if (class_dev) sysfs_remove_bin_file(&class_dev->kobj, attr); } static ssize_t class_device_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { struct class_device_attribute *class_dev_attr = to_class_dev_attr(attr); struct class_device *cd = to_class_dev(kobj); ssize_t ret = 0; if (class_dev_attr->show) ret = class_dev_attr->show(cd, buf); return ret; } static ssize_t class_device_attr_store(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { struct class_device_attribute *class_dev_attr = to_class_dev_attr(attr); struct class_device *cd = to_class_dev(kobj); ssize_t ret = 0; if (class_dev_attr->store) ret = class_dev_attr->store(cd, buf, count); return ret; } static struct sysfs_ops class_dev_sysfs_ops = { .show = class_device_attr_show, .store = class_device_attr_store, }; static void class_dev_release(struct kobject *kobj) { struct class_device *cd = to_class_dev(kobj); struct class *cls = cd->class; pr_debug("device class '%s': release.\n", cd->class_id); if (cd->release) cd->release(cd); else if (cls->release) cls->release(cd); else { printk(KERN_ERR "Class Device '%s' does not have a release() " "function, it is broken and must be fixed.\n", cd->class_id); WARN_ON(1); } } static struct kobj_type class_device_ktype = { .sysfs_ops = &class_dev_sysfs_ops, .release = class_dev_release, }; static int class_uevent_filter(struct kset *kset, struct kobject *kobj) { struct kobj_type *ktype = get_ktype(kobj); if (ktype == &class_device_ktype) { struct class_device *class_dev = to_class_dev(kobj); if (class_dev->class) return 1; } return 0; } static const char *class_uevent_name(struct kset *kset, struct kobject *kobj) { struct class_device *class_dev = to_class_dev(kobj); return class_dev->class->name; } #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; } static int make_deprecated_class_device_links(struct class_device *class_dev) { char *class_name; int error; if (!class_dev->dev) return 0; class_name = make_class_name(class_dev->class->name, &class_dev->kobj); if (class_name) error = sysfs_create_link(&class_dev->dev->kobj, &class_dev->kobj, class_name); else error = -ENOMEM; kfree(class_name); return error; } static void remove_deprecated_class_device_links(struct class_device *class_dev) { char *class_name; if (!class_dev->dev) return; class_name = make_class_name(class_dev->class->name, &class_dev->kobj); if (class_name) sysfs_remove_link(&class_dev->dev->kobj, class_name); kfree(class_name); } #else static inline int make_deprecated_class_device_links(struct class_device *cd) { return 0; } static void remove_deprecated_class_device_links(struct class_device *cd) { } #endif static int class_uevent(struct kset *kset, struct kobject *kobj, struct kobj_uevent_env *env) { struct class_device *class_dev = to_class_dev(kobj); struct device *dev = class_dev->dev; int retval = 0; pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id); if (MAJOR(class_dev->devt)) { add_uevent_var(env, "MAJOR=%u", MAJOR(class_dev->devt)); add_uevent_var(env, "MINOR=%u", MINOR(class_dev->devt)); } if (dev) { const char *path = kobject_get_path(&dev->kobj, GFP_KERNEL); if (path) { add_uevent_var(env, "PHYSDEVPATH=%s", path); kfree(path); } if (dev->bus) add_uevent_var(env, "PHYSDEVBUS=%s", dev->bus->name); if (dev->driver) add_uevent_var(env, "PHYSDEVDRIVER=%s", dev->driver->name); } if (class_dev->uevent) { /* have the class device specific function add its stuff */ retval = class_dev->uevent(class_dev, env); if (retval) pr_debug("class_dev->uevent() returned %d\n", retval); } else if (class_dev->class->uevent) { /* have the class specific function add its stuff */ retval = class_dev->class->uevent(class_dev, env); if (retval) pr_debug("class->uevent() returned %d\n", retval); } return retval; } static struct kset_uevent_ops class_uevent_ops = { .filter = class_uevent_filter, .name = class_uevent_name, .uevent = class_uevent, }; /* * DO NOT copy how this is created, kset_create_and_add() should be * called, but this is a hold-over from the old-way and will be deleted * entirely soon. */ static struct kset class_obj_subsys = { .uevent_ops = &class_uevent_ops, }; static int class_device_add_attrs(struct class_device *cd) { int i; int error = 0; struct class *cls = cd->class; if (cls->class_dev_attrs) { for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) { error = class_device_create_file(cd, &cls->class_dev_attrs[i]); if (error) goto err; } } done: return error; err: while (--i >= 0) class_device_remove_file(cd, &cls->class_dev_attrs[i]); goto done; } static void class_device_remove_attrs(struct class_device *cd) { int i; struct class *cls = cd->class; if (cls->class_dev_attrs) { for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) class_device_remove_file(cd, &cls->class_dev_attrs[i]); } } static int class_device_add_groups(struct class_device *cd) { int i; int error = 0; if (cd->groups) { for (i = 0; cd->groups[i]; i++) { error = sysfs_create_group(&cd->kobj, cd->groups[i]); if (error) { while (--i >= 0) sysfs_remove_group(&cd->kobj, cd->groups[i]); goto out; } } } out: return error; } static void class_device_remove_groups(struct class_device *cd) { int i; if (cd->groups) for (i = 0; cd->groups[i]; i++) sysfs_remove_group(&cd->kobj, cd->groups[i]); } static ssize_t show_dev(struct class_device *class_dev, char *buf) { return print_dev_t(buf, class_dev->devt); } static struct class_device_attribute class_devt_attr = __ATTR(dev, S_IRUGO, show_dev, NULL); static ssize_t store_uevent(struct class_device *class_dev, const char *buf, size_t count) { kobject_uevent(&class_dev->kobj, KOBJ_ADD); return count; } static struct class_device_attribute class_uevent_attr = __ATTR(uevent, S_IWUSR, NULL, store_uevent); void class_device_initialize(struct class_device *class_dev) { class_dev->kobj.kset = &class_obj_subsys; kobject_init(&class_dev->kobj, &class_device_ktype); INIT_LIST_HEAD(&class_dev->node); } int class_device_add(struct class_device *class_dev) { struct class *parent_class = NULL; struct class_device *parent_class_dev = NULL; struct class_interface *class_intf; int error = -EINVAL; class_dev = class_device_get(class_dev); if (!class_dev) return -EINVAL; if (!strlen(class_dev->class_id)) goto out1; parent_class = class_get(class_dev->class); if (!parent_class) goto out1; parent_class_dev = class_device_get(class_dev->parent); pr_debug("CLASS: registering class device: ID = '%s'\n", class_dev->class_id); /* first, register with generic layer. */ if (parent_class_dev) class_dev->kobj.parent = &parent_class_dev->kobj; else class_dev->kobj.parent = &parent_class->subsys.kobj; error = kobject_add(&class_dev->kobj, class_dev->kobj.parent, "%s", class_dev->class_id); if (error) goto out2; /* add the needed attributes to this device */ error = sysfs_create_link(&class_dev->kobj, &parent_class->subsys.kobj, "subsystem"); if (error) goto out3; error = class_device_create_file(class_dev, &class_uevent_attr); if (error) goto out3; if (MAJOR(class_dev->devt)) { error = class_device_create_file(class_dev, &class_devt_attr); if (error) goto out4; } error = class_device_add_attrs(class_dev); if (error) goto out5; if (class_dev->dev) { error = sysfs_create_link(&class_dev->kobj, &class_dev->dev->kobj, "device"); if (error) goto out6; } error = class_device_add_groups(class_dev); if (error) goto out7; error = make_deprecated_class_device_links(class_dev); if (error) goto out8; kobject_uevent(&class_dev->kobj, KOBJ_ADD); /* notify any interfaces this device is now here */ down(&parent_class->sem); list_add_tail(&class_dev->node, &parent_class->children); list_for_each_entry(class_intf, &parent_class->interfaces, node) { if (class_intf->add) class_intf->add(class_dev, class_intf); } up(&parent_class->sem); goto out1; out8: class_device_remove_groups(class_dev); out7: if (class_dev->dev) sysfs_remove_link(&class_dev->kobj, "device"); out6: class_device_remove_attrs(class_dev); out5: if (MAJOR(class_dev->devt)) class_device_remove_file(class_dev, &class_devt_attr); out4: class_device_remove_file(class_dev, &class_uevent_attr); out3: kobject_del(&class_dev->kobj); out2: if (parent_class_dev) class_device_put(parent_class_dev); class_put(parent_class); out1: class_device_put(class_dev); return error; } int class_device_register(struct class_device *class_dev) { class_device_initialize(class_dev); return class_device_add(class_dev); } /** * class_device_create - creates a class device and registers it with sysfs * @cls: pointer to the struct class that this device should be registered to. * @parent: pointer to the parent struct class_device of this new device, if * any. * @devt: the dev_t for the char device to be added. * @device: a pointer to a struct device that is assiociated with this class * device. * @fmt: string for the class device's name * * This function can be used by char device classes. A struct * class_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 class_device is passed in, the newly * created struct class_device will be a child of that device in sysfs. * The pointer to the struct class_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 class_device *class_device_create(struct class *cls, struct class_device *parent, dev_t devt, struct device *device, const char *fmt, ...) { va_list args; struct class_device *class_dev = NULL; int retval = -ENODEV; if (cls == NULL || IS_ERR(cls)) goto error; class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL); if (!class_dev) { retval = -ENOMEM; goto error; } class_dev->devt = devt; class_dev->dev = device; class_dev->class = cls; class_dev->parent = parent; class_dev->release = class_device_create_release; class_dev->uevent = class_device_create_uevent; va_start(args, fmt); vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args); va_end(args); retval = class_device_register(class_dev); if (retval) goto error; return class_dev; error: kfree(class_dev); return ERR_PTR(retval); } void class_device_del(struct class_device *class_dev) { struct class *parent_class = class_dev->class; struct class_device *parent_device = class_dev->parent; struct class_interface *class_intf; if (parent_class) { down(&parent_class->sem); list_del_init(&class_dev->node); list_for_each_entry(class_intf, &parent_class->interfaces, node) if (class_intf->remove) class_intf->remove(class_dev, class_intf); up(&parent_class->sem); } if (class_dev->dev) { remove_deprecated_class_device_links(class_dev); sysfs_remove_link(&class_dev->kobj, "device"); } sysfs_remove_link(&class_dev->kobj, "subsystem"); class_device_remove_file(class_dev, &class_uevent_attr); if (MAJOR(class_dev->devt)) class_device_remove_file(class_dev, &class_devt_attr); class_device_remove_attrs(class_dev); class_device_remove_groups(class_dev); kobject_uevent(&class_dev->kobj, KOBJ_REMOVE); kobject_del(&class_dev->kobj); class_device_put(parent_device); class_put(parent_class); } void class_device_unregister(struct class_device *class_dev) { pr_debug("CLASS: Unregistering class device. ID = '%s'\n", class_dev->class_id); class_device_del(class_dev); class_device_put(class_dev); } /** * class_device_destroy - removes a class device that was created with class_device_create() * @cls: the 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 class device that was created with a * call to class_device_create() */ void class_device_destroy(struct class *cls, dev_t devt) { struct class_device *class_dev = NULL; struct class_device *class_dev_tmp; down(&cls->sem); list_for_each_entry(class_dev_tmp, &cls->children, node) { if (class_dev_tmp->devt == devt) { class_dev = class_dev_tmp; break; } } up(&cls->sem); if (class_dev) class_device_unregister(class_dev); } struct class_device *class_device_get(struct class_device *class_dev) { if (class_dev) return to_class_dev(kobject_get(&class_dev->kobj)); return NULL; } void class_device_put(struct class_device *class_dev) { if (class_dev) kobject_put(&class_dev->kobj); } /** * class_for_each_device - device iterator * @class: the class we're iterating * @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. * * 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->sem 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, void *data, int (*fn)(struct device *, void *)) { struct device *dev; int error = 0; if (!class) return -EINVAL; down(&class->sem); list_for_each_entry(dev, &class->devices, node) { dev = get_device(dev); if (dev) { error = fn(dev, data); put_device(dev); } else error = -ENODEV; if (error) break; } up(&class->sem); 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 * @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->sem 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, void *data, int (*match)(struct device *, void *)) { struct device *dev; int found = 0; if (!class) return NULL; down(&class->sem); list_for_each_entry(dev, &class->devices, node) { dev = get_device(dev); if (dev) { if (match(dev, data)) { found = 1; break; } else put_device(dev); } else break; } up(&class->sem); return found ? dev : NULL; } EXPORT_SYMBOL_GPL(class_find_device); /** * class_find_child - device iterator for locating a particular class_device * @class: the class we're iterating * @data: data for the match function * @match: function to check class_device * * This function returns a reference to a class_device that is 'found' for * later use, as determined by the @match callback. * * The callback should return 0 if the class_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 class_devices. * * Note, you will need to drop the reference with class_device_put() after use. * * We hold class->sem 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 class_device *class_find_child(struct class *class, void *data, int (*match)(struct class_device *, void *)) { struct class_device *dev; int found = 0; if (!class) return NULL; down(&class->sem); list_for_each_entry(dev, &class->children, node) { dev = class_device_get(dev); if (dev) { if (match(dev, data)) { found = 1; break; } else class_device_put(dev); } else break; } up(&class->sem); return found ? dev : NULL; } EXPORT_SYMBOL_GPL(class_find_child); int class_interface_register(struct class_interface *class_intf) { struct class *parent; struct class_device *class_dev; struct device *dev; if (!class_intf || !class_intf->class) return -ENODEV; parent = class_get(class_intf->class); if (!parent) return -EINVAL; down(&parent->sem); list_add_tail(&class_intf->node, &parent->interfaces); if (class_intf->add) { list_for_each_entry(class_dev, &parent->children, node) class_intf->add(class_dev, class_intf); } if (class_intf->add_dev) { list_for_each_entry(dev, &parent->devices, node) class_intf->add_dev(dev, class_intf); } up(&parent->sem); return 0; } void class_interface_unregister(struct class_interface *class_intf) { struct class *parent = class_intf->class; struct class_device *class_dev; struct device *dev; if (!parent) return; down(&parent->sem); list_del_init(&class_intf->node); if (class_intf->remove) { list_for_each_entry(class_dev, &parent->children, node) class_intf->remove(class_dev, class_intf); } if (class_intf->remove_dev) { list_for_each_entry(dev, &parent->devices, node) class_intf->remove_dev(dev, class_intf); } up(&parent->sem); class_put(parent); } int __init classes_init(void) { class_kset = kset_create_and_add("class", NULL, NULL); if (!class_kset) return -ENOMEM; /* ick, this is ugly, the things we go through to keep from showing up * in sysfs... */ kset_init(&class_obj_subsys); kobject_set_name(&class_obj_subsys.kobj, "class_obj"); if (!class_obj_subsys.kobj.parent) class_obj_subsys.kobj.parent = &class_obj_subsys.kobj; return 0; } EXPORT_SYMBOL_GPL(class_create_file); EXPORT_SYMBOL_GPL(class_remove_file); EXPORT_SYMBOL_GPL(class_register); EXPORT_SYMBOL_GPL(class_unregister); EXPORT_SYMBOL_GPL(class_create); EXPORT_SYMBOL_GPL(class_destroy); EXPORT_SYMBOL_GPL(class_device_register); EXPORT_SYMBOL_GPL(class_device_unregister); EXPORT_SYMBOL_GPL(class_device_initialize); EXPORT_SYMBOL_GPL(class_device_add); EXPORT_SYMBOL_GPL(class_device_del); EXPORT_SYMBOL_GPL(class_device_get); EXPORT_SYMBOL_GPL(class_device_put); EXPORT_SYMBOL_GPL(class_device_create); EXPORT_SYMBOL_GPL(class_device_destroy); EXPORT_SYMBOL_GPL(class_device_create_file); EXPORT_SYMBOL_GPL(class_device_remove_file); EXPORT_SYMBOL_GPL(class_device_create_bin_file); EXPORT_SYMBOL_GPL(class_device_remove_bin_file); EXPORT_SYMBOL_GPL(class_interface_register); EXPORT_SYMBOL_GPL(class_interface_unregister);