/* * attribute_container.c - implementation of a simple container for classes * * Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com> * * This file is licensed under GPLv2 * * The basic idea here is to enable a device to be attached to an * aritrary numer of classes without having to allocate storage for them. * Instead, the contained classes select the devices they need to attach * to via a matching function. */ #include <linux/attribute_container.h> #include <linux/init.h> #include <linux/device.h> #include <linux/kernel.h> #include <linux/slab.h> #include <linux/list.h> #include <linux/module.h> #include "base.h" /* This is a private structure used to tie the classdev and the * container .. it should never be visible outside this file */ struct internal_container { struct klist_node node; struct attribute_container *cont; struct class_device classdev; }; static void internal_container_klist_get(struct klist_node *n) { struct internal_container *ic = container_of(n, struct internal_container, node); class_device_get(&ic->classdev); } static void internal_container_klist_put(struct klist_node *n) { struct internal_container *ic = container_of(n, struct internal_container, node); class_device_put(&ic->classdev); } /** * attribute_container_classdev_to_container - given a classdev, return the container * * @classdev: the class device created by attribute_container_add_device. * * Returns the container associated with this classdev. */ struct attribute_container * attribute_container_classdev_to_container(struct class_device *classdev) { struct internal_container *ic = container_of(classdev, struct internal_container, classdev); return ic->cont; } EXPORT_SYMBOL_GPL(attribute_container_classdev_to_container); static struct list_head attribute_container_list; static DECLARE_MUTEX(attribute_container_mutex); /** * attribute_container_register - register an attribute container * * @cont: The container to register. This must be allocated by the * callee and should also be zeroed by it. */ int attribute_container_register(struct attribute_container *cont) { INIT_LIST_HEAD(&cont->node); klist_init(&cont->containers,internal_container_klist_get, internal_container_klist_put); down(&attribute_container_mutex); list_add_tail(&cont->node, &attribute_container_list); up(&attribute_container_mutex); return 0; } EXPORT_SYMBOL_GPL(attribute_container_register); /** * attribute_container_unregister - remove a container registration * * @cont: previously registered container to remove */ int attribute_container_unregister(struct attribute_container *cont) { int retval = -EBUSY; down(&attribute_container_mutex); spin_lock(&cont->containers.k_lock); if (!list_empty(&cont->containers.k_list)) goto out; retval = 0; list_del(&cont->node); out: spin_unlock(&cont->containers.k_lock); up(&attribute_container_mutex); return retval; } EXPORT_SYMBOL_GPL(attribute_container_unregister); /* private function used as class release */ static void attribute_container_release(struct class_device *classdev) { struct internal_container *ic = container_of(classdev, struct internal_container, classdev); struct device *dev = classdev->dev; kfree(ic); put_device(dev); } /** * attribute_container_add_device - see if any container is interested in dev * * @dev: device to add attributes to * @fn: function to trigger addition of class device. * * This function allocates storage for the class device(s) to be * attached to dev (one for each matching attribute_container). If no * fn is provided, the code will simply register the class device via * class_device_add. If a function is provided, it is expected to add * the class device at the appropriate time. One of the things that * might be necessary is to allocate and initialise the classdev and * then add it a later time. To do this, call this routine for * allocation and initialisation and then use * attribute_container_device_trigger() to call class_device_add() on * it. Note: after this, the class device contains a reference to dev * which is not relinquished until the release of the classdev. */ void attribute_container_add_device(struct device *dev, int (*fn)(struct attribute_container *, struct device *, struct class_device *)) { struct attribute_container *cont; down(&attribute_container_mutex); list_for_each_entry(cont, &attribute_container_list, node) { struct internal_container *ic; if (attribute_container_no_classdevs(cont)) continue; if (!cont->match(cont, dev)) continue; ic = kzalloc(sizeof(*ic), GFP_KERNEL); if (!ic) { dev_printk(KERN_ERR, dev, "failed to allocate class container\n"); continue; } ic->cont = cont; class_device_initialize(&ic->classdev); ic->classdev.dev = get_device(dev); ic->classdev.class = cont->class; cont->class->release = attribute_container_release; strcpy(ic->classdev.class_id, dev->bus_id); if (fn) fn(cont, dev, &ic->classdev); else attribute_container_add_class_device(&ic->classdev); klist_add_tail(&ic->node, &cont->containers); } up(&attribute_container_mutex); } /* FIXME: can't break out of this unless klist_iter_exit is also * called before doing the break */ #define klist_for_each_entry(pos, head, member, iter) \ for (klist_iter_init(head, iter); (pos = ({ \ struct klist_node *n = klist_next(iter); \ n ? container_of(n, typeof(*pos), member) : \ ({ klist_iter_exit(iter) ; NULL; }); \ }) ) != NULL; ) /** * attribute_container_remove_device - make device eligible for removal. * * @dev: The generic device * @fn: A function to call to remove the device * * This routine triggers device removal. If fn is NULL, then it is * simply done via class_device_unregister (note that if something * still has a reference to the classdev, then the memory occupied * will not be freed until the classdev is released). If you want a * two phase release: remove from visibility and then delete the * device, then you should use this routine with a fn that calls * class_device_del() and then use * attribute_container_device_trigger() to do the final put on the * classdev. */ void attribute_container_remove_device(struct device *dev, void (*fn)(struct attribute_container *, struct device *, struct class_device *)) { struct attribute_container *cont; down(&attribute_container_mutex); list_for_each_entry(cont, &attribute_container_list, node) { struct internal_container *ic; struct klist_iter iter; if (attribute_container_no_classdevs(cont)) continue; if (!cont->match(cont, dev)) continue; klist_for_each_entry(ic, &cont->containers, node, &iter) { if (dev != ic->classdev.dev) continue; klist_del(&ic->node); if (fn) fn(cont, dev, &ic->classdev); else { attribute_container_remove_attrs(&ic->classdev); class_device_unregister(&ic->classdev); } } } up(&attribute_container_mutex); } /** * attribute_container_device_trigger - execute a trigger for each matching classdev * * @dev: The generic device to run the trigger for * @fn the function to execute for each classdev. * * This funcion is for executing a trigger when you need to know both * the container and the classdev. If you only care about the * container, then use attribute_container_trigger() instead. */ void attribute_container_device_trigger(struct device *dev, int (*fn)(struct attribute_container *, struct device *, struct class_device *)) { struct attribute_container *cont; down(&attribute_container_mutex); list_for_each_entry(cont, &attribute_container_list, node) { struct internal_container *ic; struct klist_iter iter; if (!cont->match(cont, dev)) continue; if (attribute_container_no_classdevs(cont)) { fn(cont, dev, NULL); continue; } klist_for_each_entry(ic, &cont->containers, node, &iter) { if (dev == ic->classdev.dev) fn(cont, dev, &ic->classdev); } } up(&attribute_container_mutex); } /** * attribute_container_trigger - trigger a function for each matching container * * @dev: The generic device to activate the trigger for * @fn: the function to trigger * * This routine triggers a function that only needs to know the * matching containers (not the classdev) associated with a device. * It is more lightweight than attribute_container_device_trigger, so * should be used in preference unless the triggering function * actually needs to know the classdev. */ void attribute_container_trigger(struct device *dev, int (*fn)(struct attribute_container *, struct device *)) { struct attribute_container *cont; down(&attribute_container_mutex); list_for_each_entry(cont, &attribute_container_list, node) { if (cont->match(cont, dev)) fn(cont, dev); } up(&attribute_container_mutex); } /** * attribute_container_add_attrs - add attributes * * @classdev: The class device * * This simply creates all the class device sysfs files from the * attributes listed in the container */ int attribute_container_add_attrs(struct class_device *classdev) { struct attribute_container *cont = attribute_container_classdev_to_container(classdev); struct class_device_attribute **attrs = cont->attrs; int i, error; if (!attrs) return 0; for (i = 0; attrs[i]; i++) { error = class_device_create_file(classdev, attrs[i]); if (error) return error; } return 0; } /** * attribute_container_add_class_device - same function as class_device_add * * @classdev: the class device to add * * This performs essentially the same function as class_device_add except for * attribute containers, namely add the classdev to the system and then * create the attribute files */ int attribute_container_add_class_device(struct class_device *classdev) { int error = class_device_add(classdev); if (error) return error; return attribute_container_add_attrs(classdev); } /** * attribute_container_add_class_device_adapter - simple adapter for triggers * * This function is identical to attribute_container_add_class_device except * that it is designed to be called from the triggers */ int attribute_container_add_class_device_adapter(struct attribute_container *cont, struct device *dev, struct class_device *classdev) { return attribute_container_add_class_device(classdev); } /** * attribute_container_remove_attrs - remove any attribute files * * @classdev: The class device to remove the files from * */ void attribute_container_remove_attrs(struct class_device *classdev) { struct attribute_container *cont = attribute_container_classdev_to_container(classdev); struct class_device_attribute **attrs = cont->attrs; int i; if (!attrs) return; for (i = 0; attrs[i]; i++) class_device_remove_file(classdev, attrs[i]); } /** * attribute_container_class_device_del - equivalent of class_device_del * * @classdev: the class device * * This function simply removes all the attribute files and then calls * class_device_del. */ void attribute_container_class_device_del(struct class_device *classdev) { attribute_container_remove_attrs(classdev); class_device_del(classdev); } /** * attribute_container_find_class_device - find the corresponding class_device * * @cont: the container * @dev: the generic device * * Looks up the device in the container's list of class devices and returns * the corresponding class_device. */ struct class_device * attribute_container_find_class_device(struct attribute_container *cont, struct device *dev) { struct class_device *cdev = NULL; struct internal_container *ic; struct klist_iter iter; klist_for_each_entry(ic, &cont->containers, node, &iter) { if (ic->classdev.dev == dev) { cdev = &ic->classdev; /* FIXME: must exit iterator then break */ klist_iter_exit(&iter); break; } } return cdev; } EXPORT_SYMBOL_GPL(attribute_container_find_class_device); int __init attribute_container_init(void) { INIT_LIST_HEAD(&attribute_container_list); return 0; }