| /* |
| * 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 |
| * |
| * This file is released under the GPLv2 |
| * |
| */ |
| |
| #include <linux/config.h> |
| #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 <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. |
| */ |
| |
| #define to_dev(obj) container_of(obj, struct device, kobj) |
| #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr) |
| |
| extern struct attribute * dev_default_attrs[]; |
| |
| 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 = 0; |
| |
| if (dev_attr->show) |
| ret = dev_attr->show(dev, 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 = 0; |
| |
| if (dev_attr->store) |
| ret = dev_attr->store(dev, 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 { |
| 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, |
| .default_attrs = dev_default_attrs, |
| }; |
| |
| |
| static int dev_hotplug_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; |
| } |
| return 0; |
| } |
| |
| static char *dev_hotplug_name(struct kset *kset, struct kobject *kobj) |
| { |
| struct device *dev = to_dev(kobj); |
| |
| return dev->bus->name; |
| } |
| |
| static int dev_hotplug(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 bus name of physical device */ |
| if (dev->bus) |
| add_hotplug_env_var(envp, num_envp, &i, |
| buffer, buffer_size, &length, |
| "PHYSDEVBUS=%s", dev->bus->name); |
| |
| /* add driver name of physical device */ |
| if (dev->driver) |
| add_hotplug_env_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->hotplug) { |
| /* have the bus specific function add its stuff */ |
| retval = dev->bus->hotplug (dev, envp, num_envp, buffer, buffer_size); |
| if (retval) { |
| pr_debug ("%s - hotplug() returned %d\n", |
| __FUNCTION__, retval); |
| } |
| } |
| |
| return retval; |
| } |
| |
| static struct kset_hotplug_ops device_hotplug_ops = { |
| .filter = dev_hotplug_filter, |
| .name = dev_hotplug_name, |
| .hotplug = dev_hotplug, |
| }; |
| |
| /** |
| * device_subsys - structure to be registered with kobject core. |
| */ |
| |
| decl_subsys(devices, &ktype_device, &device_hotplug_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_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); |
| INIT_LIST_HEAD(&dev->node); |
| INIT_LIST_HEAD(&dev->children); |
| INIT_LIST_HEAD(&dev->driver_list); |
| INIT_LIST_HEAD(&dev->bus_list); |
| INIT_LIST_HEAD(&dev->dma_pools); |
| } |
| |
| /** |
| * 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; |
| int error = -EINVAL; |
| |
| dev = get_device(dev); |
| if (!dev || !strlen(dev->bus_id)) |
| 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; |
| if ((error = device_pm_add(dev))) |
| goto PMError; |
| if ((error = bus_add_device(dev))) |
| goto BusError; |
| down_write(&devices_subsys.rwsem); |
| if (parent) |
| list_add_tail(&dev->node, &parent->children); |
| up_write(&devices_subsys.rwsem); |
| |
| /* notify platform of device entry */ |
| if (platform_notify) |
| platform_notify(dev); |
| |
| kobject_hotplug(&dev->kobj, KOBJ_ADD); |
| Done: |
| put_device(dev); |
| return error; |
| BusError: |
| device_pm_remove(dev); |
| PMError: |
| 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; |
| |
| down_write(&devices_subsys.rwsem); |
| if (parent) |
| list_del_init(&dev->node); |
| up_write(&devices_subsys.rwsem); |
| |
| /* 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_hotplug(&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); |
| } |
| |
| |
| /** |
| * device_for_each_child - device child iterator. |
| * @dev: parent struct device. |
| * @data: data for the callback. |
| * @fn: function to be called for each device. |
| * |
| * Iterate over @dev'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 * dev, void * data, |
| int (*fn)(struct device *, void *)) |
| { |
| struct device * child; |
| int error = 0; |
| |
| down_read(&devices_subsys.rwsem); |
| list_for_each_entry(child, &dev->children, node) { |
| if((error = fn(child, data))) |
| break; |
| } |
| up_read(&devices_subsys.rwsem); |
| return error; |
| } |
| |
| /** |
| * device_find - locate device on a bus by name. |
| * @name: name of the device. |
| * @bus: bus to scan for the device. |
| * |
| * Call kset_find_obj() to iterate over list of devices on |
| * a bus to find device by name. Return device if found. |
| * |
| * Note that kset_find_obj increments device's reference count. |
| */ |
| struct device *device_find(const char *name, struct bus_type *bus) |
| { |
| struct kobject *k = kset_find_obj(&bus->devices, name); |
| if (k) |
| return to_dev(k); |
| return NULL; |
| } |
| |
| 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_find); |
| |
| EXPORT_SYMBOL_GPL(device_create_file); |
| EXPORT_SYMBOL_GPL(device_remove_file); |