| /* |
| * bus.c - bus driver management |
| * |
| * 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/module.h> |
| #include <linux/errno.h> |
| #include <linux/init.h> |
| #include <linux/string.h> |
| #include "base.h" |
| #include "power/power.h" |
| |
| #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr) |
| #define to_bus(obj) container_of(obj, struct bus_type, subsys.kset.kobj) |
| |
| /* |
| * sysfs bindings for drivers |
| */ |
| |
| #define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr) |
| #define to_driver(obj) container_of(obj, struct device_driver, kobj) |
| |
| |
| static ssize_t |
| drv_attr_show(struct kobject * kobj, struct attribute * attr, char * buf) |
| { |
| struct driver_attribute * drv_attr = to_drv_attr(attr); |
| struct device_driver * drv = to_driver(kobj); |
| ssize_t ret = -EIO; |
| |
| if (drv_attr->show) |
| ret = drv_attr->show(drv, buf); |
| return ret; |
| } |
| |
| static ssize_t |
| drv_attr_store(struct kobject * kobj, struct attribute * attr, |
| const char * buf, size_t count) |
| { |
| struct driver_attribute * drv_attr = to_drv_attr(attr); |
| struct device_driver * drv = to_driver(kobj); |
| ssize_t ret = -EIO; |
| |
| if (drv_attr->store) |
| ret = drv_attr->store(drv, buf, count); |
| return ret; |
| } |
| |
| static struct sysfs_ops driver_sysfs_ops = { |
| .show = drv_attr_show, |
| .store = drv_attr_store, |
| }; |
| |
| |
| static void driver_release(struct kobject * kobj) |
| { |
| struct device_driver * drv = to_driver(kobj); |
| complete(&drv->unloaded); |
| } |
| |
| static struct kobj_type ktype_driver = { |
| .sysfs_ops = &driver_sysfs_ops, |
| .release = driver_release, |
| }; |
| |
| |
| /* |
| * sysfs bindings for buses |
| */ |
| |
| |
| static ssize_t |
| bus_attr_show(struct kobject * kobj, struct attribute * attr, char * buf) |
| { |
| struct bus_attribute * bus_attr = to_bus_attr(attr); |
| struct bus_type * bus = to_bus(kobj); |
| ssize_t ret = 0; |
| |
| if (bus_attr->show) |
| ret = bus_attr->show(bus, buf); |
| return ret; |
| } |
| |
| static ssize_t |
| bus_attr_store(struct kobject * kobj, struct attribute * attr, |
| const char * buf, size_t count) |
| { |
| struct bus_attribute * bus_attr = to_bus_attr(attr); |
| struct bus_type * bus = to_bus(kobj); |
| ssize_t ret = 0; |
| |
| if (bus_attr->store) |
| ret = bus_attr->store(bus, buf, count); |
| return ret; |
| } |
| |
| static struct sysfs_ops bus_sysfs_ops = { |
| .show = bus_attr_show, |
| .store = bus_attr_store, |
| }; |
| |
| int bus_create_file(struct bus_type * bus, struct bus_attribute * attr) |
| { |
| int error; |
| if (get_bus(bus)) { |
| error = sysfs_create_file(&bus->subsys.kset.kobj, &attr->attr); |
| put_bus(bus); |
| } else |
| error = -EINVAL; |
| return error; |
| } |
| |
| void bus_remove_file(struct bus_type * bus, struct bus_attribute * attr) |
| { |
| if (get_bus(bus)) { |
| sysfs_remove_file(&bus->subsys.kset.kobj, &attr->attr); |
| put_bus(bus); |
| } |
| } |
| |
| static struct kobj_type ktype_bus = { |
| .sysfs_ops = &bus_sysfs_ops, |
| |
| }; |
| |
| decl_subsys(bus, &ktype_bus, NULL); |
| |
| |
| #ifdef CONFIG_HOTPLUG |
| |
| /* Manually detach a device from its associated driver. */ |
| static int driver_helper(struct device *dev, void *data) |
| { |
| const char *name = data; |
| |
| if (strcmp(name, dev->bus_id) == 0) |
| return 1; |
| return 0; |
| } |
| |
| static ssize_t driver_unbind(struct device_driver *drv, |
| const char *buf, size_t count) |
| { |
| struct bus_type *bus = get_bus(drv->bus); |
| struct device *dev; |
| int err = -ENODEV; |
| |
| dev = bus_find_device(bus, NULL, (void *)buf, driver_helper); |
| if (dev && dev->driver == drv) { |
| if (dev->parent) /* Needed for USB */ |
| down(&dev->parent->sem); |
| device_release_driver(dev); |
| if (dev->parent) |
| up(&dev->parent->sem); |
| err = count; |
| } |
| put_device(dev); |
| put_bus(bus); |
| return err; |
| } |
| static DRIVER_ATTR(unbind, S_IWUSR, NULL, driver_unbind); |
| |
| /* |
| * Manually attach a device to a driver. |
| * Note: the driver must want to bind to the device, |
| * it is not possible to override the driver's id table. |
| */ |
| static ssize_t driver_bind(struct device_driver *drv, |
| const char *buf, size_t count) |
| { |
| struct bus_type *bus = get_bus(drv->bus); |
| struct device *dev; |
| int err = -ENODEV; |
| |
| dev = bus_find_device(bus, NULL, (void *)buf, driver_helper); |
| if (dev && dev->driver == NULL) { |
| if (dev->parent) /* Needed for USB */ |
| down(&dev->parent->sem); |
| down(&dev->sem); |
| err = driver_probe_device(drv, dev); |
| up(&dev->sem); |
| if (dev->parent) |
| up(&dev->parent->sem); |
| |
| if (err > 0) /* success */ |
| err = count; |
| else if (err == 0) /* driver didn't accept device */ |
| err = -ENODEV; |
| } |
| put_device(dev); |
| put_bus(bus); |
| return err; |
| } |
| static DRIVER_ATTR(bind, S_IWUSR, NULL, driver_bind); |
| |
| #endif |
| |
| static struct device * next_device(struct klist_iter * i) |
| { |
| struct klist_node * n = klist_next(i); |
| return n ? container_of(n, struct device, knode_bus) : NULL; |
| } |
| |
| /** |
| * bus_for_each_dev - device iterator. |
| * @bus: bus type. |
| * @start: device to start iterating from. |
| * @data: data for the callback. |
| * @fn: function to be called for each device. |
| * |
| * Iterate over @bus's list of devices, and call @fn for each, |
| * passing it @data. If @start is not NULL, we use that device to |
| * begin iterating from. |
| * |
| * We check the return of @fn each time. If it returns anything |
| * other than 0, we break out and return that value. |
| * |
| * NOTE: The device that returns a non-zero value is not retained |
| * in any way, nor is its refcount incremented. If the caller needs |
| * to retain this data, it should do, and increment the reference |
| * count in the supplied callback. |
| */ |
| |
| int bus_for_each_dev(struct bus_type * bus, struct device * start, |
| void * data, int (*fn)(struct device *, void *)) |
| { |
| struct klist_iter i; |
| struct device * dev; |
| int error = 0; |
| |
| if (!bus) |
| return -EINVAL; |
| |
| klist_iter_init_node(&bus->klist_devices, &i, |
| (start ? &start->knode_bus : NULL)); |
| while ((dev = next_device(&i)) && !error) |
| error = fn(dev, data); |
| klist_iter_exit(&i); |
| return error; |
| } |
| |
| /** |
| * bus_find_device - device iterator for locating a particular device. |
| * @bus: bus type |
| * @start: Device to begin with |
| * @data: Data to pass to match function |
| * @match: Callback function to check device |
| * |
| * This is similar to the bus_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. |
| */ |
| struct device * bus_find_device(struct bus_type *bus, |
| struct device *start, void *data, |
| int (*match)(struct device *, void *)) |
| { |
| struct klist_iter i; |
| struct device *dev; |
| |
| if (!bus) |
| return NULL; |
| |
| klist_iter_init_node(&bus->klist_devices, &i, |
| (start ? &start->knode_bus : NULL)); |
| while ((dev = next_device(&i))) |
| if (match(dev, data) && get_device(dev)) |
| break; |
| klist_iter_exit(&i); |
| return dev; |
| } |
| |
| |
| static struct device_driver * next_driver(struct klist_iter * i) |
| { |
| struct klist_node * n = klist_next(i); |
| return n ? container_of(n, struct device_driver, knode_bus) : NULL; |
| } |
| |
| /** |
| * bus_for_each_drv - driver iterator |
| * @bus: bus we're dealing with. |
| * @start: driver to start iterating on. |
| * @data: data to pass to the callback. |
| * @fn: function to call for each driver. |
| * |
| * This is nearly identical to the device iterator above. |
| * We iterate over each driver that belongs to @bus, and call |
| * @fn for each. If @fn returns anything but 0, we break out |
| * and return it. If @start is not NULL, we use it as the head |
| * of the list. |
| * |
| * NOTE: we don't return the driver that returns a non-zero |
| * value, nor do we leave the reference count incremented for that |
| * driver. If the caller needs to know that info, it must set it |
| * in the callback. It must also be sure to increment the refcount |
| * so it doesn't disappear before returning to the caller. |
| */ |
| |
| int bus_for_each_drv(struct bus_type * bus, struct device_driver * start, |
| void * data, int (*fn)(struct device_driver *, void *)) |
| { |
| struct klist_iter i; |
| struct device_driver * drv; |
| int error = 0; |
| |
| if (!bus) |
| return -EINVAL; |
| |
| klist_iter_init_node(&bus->klist_drivers, &i, |
| start ? &start->knode_bus : NULL); |
| while ((drv = next_driver(&i)) && !error) |
| error = fn(drv, data); |
| klist_iter_exit(&i); |
| return error; |
| } |
| |
| static int device_add_attrs(struct bus_type * bus, struct device * dev) |
| { |
| int error = 0; |
| int i; |
| |
| if (bus->dev_attrs) { |
| for (i = 0; attr_name(bus->dev_attrs[i]); i++) { |
| error = device_create_file(dev,&bus->dev_attrs[i]); |
| if (error) |
| goto Err; |
| } |
| } |
| Done: |
| return error; |
| Err: |
| while (--i >= 0) |
| device_remove_file(dev,&bus->dev_attrs[i]); |
| goto Done; |
| } |
| |
| |
| static void device_remove_attrs(struct bus_type * bus, struct device * dev) |
| { |
| int i; |
| |
| if (bus->dev_attrs) { |
| for (i = 0; attr_name(bus->dev_attrs[i]); i++) |
| device_remove_file(dev,&bus->dev_attrs[i]); |
| } |
| } |
| |
| |
| /** |
| * bus_add_device - add device to bus |
| * @dev: device being added |
| * |
| * - Add the device to its bus's list of devices. |
| * - Create link to device's bus. |
| */ |
| int bus_add_device(struct device * dev) |
| { |
| struct bus_type * bus = get_bus(dev->bus); |
| int error = 0; |
| |
| if (bus) { |
| pr_debug("bus %s: add device %s\n", bus->name, dev->bus_id); |
| error = device_add_attrs(bus, dev); |
| if (!error) { |
| sysfs_create_link(&bus->devices.kobj, &dev->kobj, dev->bus_id); |
| sysfs_create_link(&dev->kobj, &dev->bus->subsys.kset.kobj, "bus"); |
| } |
| } |
| return error; |
| } |
| |
| /** |
| * bus_attach_device - add device to bus |
| * @dev: device tried to attach to a driver |
| * |
| * - Try to attach to driver. |
| */ |
| void bus_attach_device(struct device * dev) |
| { |
| struct bus_type * bus = dev->bus; |
| |
| if (bus) { |
| device_attach(dev); |
| klist_add_tail(&dev->knode_bus, &bus->klist_devices); |
| } |
| } |
| |
| /** |
| * bus_remove_device - remove device from bus |
| * @dev: device to be removed |
| * |
| * - Remove symlink from bus's directory. |
| * - Delete device from bus's list. |
| * - Detach from its driver. |
| * - Drop reference taken in bus_add_device(). |
| */ |
| void bus_remove_device(struct device * dev) |
| { |
| if (dev->bus) { |
| sysfs_remove_link(&dev->kobj, "bus"); |
| sysfs_remove_link(&dev->bus->devices.kobj, dev->bus_id); |
| device_remove_attrs(dev->bus, dev); |
| klist_remove(&dev->knode_bus); |
| pr_debug("bus %s: remove device %s\n", dev->bus->name, dev->bus_id); |
| device_release_driver(dev); |
| put_bus(dev->bus); |
| } |
| } |
| |
| static int driver_add_attrs(struct bus_type * bus, struct device_driver * drv) |
| { |
| int error = 0; |
| int i; |
| |
| if (bus->drv_attrs) { |
| for (i = 0; attr_name(bus->drv_attrs[i]); i++) { |
| error = driver_create_file(drv, &bus->drv_attrs[i]); |
| if (error) |
| goto Err; |
| } |
| } |
| Done: |
| return error; |
| Err: |
| while (--i >= 0) |
| driver_remove_file(drv, &bus->drv_attrs[i]); |
| goto Done; |
| } |
| |
| |
| static void driver_remove_attrs(struct bus_type * bus, struct device_driver * drv) |
| { |
| int i; |
| |
| if (bus->drv_attrs) { |
| for (i = 0; attr_name(bus->drv_attrs[i]); i++) |
| driver_remove_file(drv, &bus->drv_attrs[i]); |
| } |
| } |
| |
| #ifdef CONFIG_HOTPLUG |
| /* |
| * Thanks to drivers making their tables __devinit, we can't allow manual |
| * bind and unbind from userspace unless CONFIG_HOTPLUG is enabled. |
| */ |
| static void add_bind_files(struct device_driver *drv) |
| { |
| driver_create_file(drv, &driver_attr_unbind); |
| driver_create_file(drv, &driver_attr_bind); |
| } |
| |
| static void remove_bind_files(struct device_driver *drv) |
| { |
| driver_remove_file(drv, &driver_attr_bind); |
| driver_remove_file(drv, &driver_attr_unbind); |
| } |
| #else |
| static inline void add_bind_files(struct device_driver *drv) {} |
| static inline void remove_bind_files(struct device_driver *drv) {} |
| #endif |
| |
| /** |
| * bus_add_driver - Add a driver to the bus. |
| * @drv: driver. |
| * |
| */ |
| int bus_add_driver(struct device_driver * drv) |
| { |
| struct bus_type * bus = get_bus(drv->bus); |
| int error = 0; |
| |
| if (bus) { |
| pr_debug("bus %s: add driver %s\n", bus->name, drv->name); |
| error = kobject_set_name(&drv->kobj, "%s", drv->name); |
| if (error) { |
| put_bus(bus); |
| return error; |
| } |
| drv->kobj.kset = &bus->drivers; |
| if ((error = kobject_register(&drv->kobj))) { |
| put_bus(bus); |
| return error; |
| } |
| |
| driver_attach(drv); |
| klist_add_tail(&drv->knode_bus, &bus->klist_drivers); |
| module_add_driver(drv->owner, drv); |
| |
| driver_add_attrs(bus, drv); |
| add_bind_files(drv); |
| } |
| return error; |
| } |
| |
| |
| /** |
| * bus_remove_driver - delete driver from bus's knowledge. |
| * @drv: driver. |
| * |
| * Detach the driver from the devices it controls, and remove |
| * it from its bus's list of drivers. Finally, we drop the reference |
| * to the bus we took in bus_add_driver(). |
| */ |
| |
| void bus_remove_driver(struct device_driver * drv) |
| { |
| if (drv->bus) { |
| remove_bind_files(drv); |
| driver_remove_attrs(drv->bus, drv); |
| klist_remove(&drv->knode_bus); |
| pr_debug("bus %s: remove driver %s\n", drv->bus->name, drv->name); |
| driver_detach(drv); |
| module_remove_driver(drv); |
| kobject_unregister(&drv->kobj); |
| put_bus(drv->bus); |
| } |
| } |
| |
| |
| /* Helper for bus_rescan_devices's iter */ |
| static int bus_rescan_devices_helper(struct device *dev, void *data) |
| { |
| if (!dev->driver) { |
| if (dev->parent) /* Needed for USB */ |
| down(&dev->parent->sem); |
| device_attach(dev); |
| if (dev->parent) |
| up(&dev->parent->sem); |
| } |
| return 0; |
| } |
| |
| /** |
| * bus_rescan_devices - rescan devices on the bus for possible drivers |
| * @bus: the bus to scan. |
| * |
| * This function will look for devices on the bus with no driver |
| * attached and rescan it against existing drivers to see if it matches |
| * any by calling device_attach() for the unbound devices. |
| */ |
| void bus_rescan_devices(struct bus_type * bus) |
| { |
| bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper); |
| } |
| |
| /** |
| * device_reprobe - remove driver for a device and probe for a new driver |
| * @dev: the device to reprobe |
| * |
| * This function detaches the attached driver (if any) for the given |
| * device and restarts the driver probing process. It is intended |
| * to use if probing criteria changed during a devices lifetime and |
| * driver attachment should change accordingly. |
| */ |
| void device_reprobe(struct device *dev) |
| { |
| if (dev->driver) { |
| if (dev->parent) /* Needed for USB */ |
| down(&dev->parent->sem); |
| device_release_driver(dev); |
| if (dev->parent) |
| up(&dev->parent->sem); |
| } |
| |
| bus_rescan_devices_helper(dev, NULL); |
| } |
| EXPORT_SYMBOL_GPL(device_reprobe); |
| |
| struct bus_type * get_bus(struct bus_type * bus) |
| { |
| return bus ? container_of(subsys_get(&bus->subsys), struct bus_type, subsys) : NULL; |
| } |
| |
| void put_bus(struct bus_type * bus) |
| { |
| subsys_put(&bus->subsys); |
| } |
| |
| |
| /** |
| * find_bus - locate bus by name. |
| * @name: name of bus. |
| * |
| * Call kset_find_obj() to iterate over list of buses to |
| * find a bus by name. Return bus if found. |
| * |
| * Note that kset_find_obj increments bus' reference count. |
| */ |
| |
| struct bus_type * find_bus(char * name) |
| { |
| struct kobject * k = kset_find_obj(&bus_subsys.kset, name); |
| return k ? to_bus(k) : NULL; |
| } |
| |
| |
| /** |
| * bus_add_attrs - Add default attributes for this bus. |
| * @bus: Bus that has just been registered. |
| */ |
| |
| static int bus_add_attrs(struct bus_type * bus) |
| { |
| int error = 0; |
| int i; |
| |
| if (bus->bus_attrs) { |
| for (i = 0; attr_name(bus->bus_attrs[i]); i++) { |
| if ((error = bus_create_file(bus,&bus->bus_attrs[i]))) |
| goto Err; |
| } |
| } |
| Done: |
| return error; |
| Err: |
| while (--i >= 0) |
| bus_remove_file(bus,&bus->bus_attrs[i]); |
| goto Done; |
| } |
| |
| static void bus_remove_attrs(struct bus_type * bus) |
| { |
| int i; |
| |
| if (bus->bus_attrs) { |
| for (i = 0; attr_name(bus->bus_attrs[i]); i++) |
| bus_remove_file(bus,&bus->bus_attrs[i]); |
| } |
| } |
| |
| static void klist_devices_get(struct klist_node *n) |
| { |
| struct device *dev = container_of(n, struct device, knode_bus); |
| |
| get_device(dev); |
| } |
| |
| static void klist_devices_put(struct klist_node *n) |
| { |
| struct device *dev = container_of(n, struct device, knode_bus); |
| |
| put_device(dev); |
| } |
| |
| static void klist_drivers_get(struct klist_node *n) |
| { |
| struct device_driver *drv = container_of(n, struct device_driver, |
| knode_bus); |
| |
| get_driver(drv); |
| } |
| |
| static void klist_drivers_put(struct klist_node *n) |
| { |
| struct device_driver *drv = container_of(n, struct device_driver, |
| knode_bus); |
| |
| put_driver(drv); |
| } |
| |
| /** |
| * bus_register - register a bus with the system. |
| * @bus: bus. |
| * |
| * Once we have that, we registered the bus with the kobject |
| * infrastructure, then register the children subsystems it has: |
| * the devices and drivers that belong to the bus. |
| */ |
| int bus_register(struct bus_type * bus) |
| { |
| int retval; |
| |
| retval = kobject_set_name(&bus->subsys.kset.kobj, "%s", bus->name); |
| if (retval) |
| goto out; |
| |
| subsys_set_kset(bus, bus_subsys); |
| retval = subsystem_register(&bus->subsys); |
| if (retval) |
| goto out; |
| |
| kobject_set_name(&bus->devices.kobj, "devices"); |
| bus->devices.subsys = &bus->subsys; |
| retval = kset_register(&bus->devices); |
| if (retval) |
| goto bus_devices_fail; |
| |
| kobject_set_name(&bus->drivers.kobj, "drivers"); |
| bus->drivers.subsys = &bus->subsys; |
| bus->drivers.ktype = &ktype_driver; |
| retval = kset_register(&bus->drivers); |
| if (retval) |
| goto bus_drivers_fail; |
| |
| klist_init(&bus->klist_devices, klist_devices_get, klist_devices_put); |
| klist_init(&bus->klist_drivers, klist_drivers_get, klist_drivers_put); |
| bus_add_attrs(bus); |
| |
| pr_debug("bus type '%s' registered\n", bus->name); |
| return 0; |
| |
| bus_drivers_fail: |
| kset_unregister(&bus->devices); |
| bus_devices_fail: |
| subsystem_unregister(&bus->subsys); |
| out: |
| return retval; |
| } |
| |
| |
| /** |
| * bus_unregister - remove a bus from the system |
| * @bus: bus. |
| * |
| * Unregister the child subsystems and the bus itself. |
| * Finally, we call put_bus() to release the refcount |
| */ |
| void bus_unregister(struct bus_type * bus) |
| { |
| pr_debug("bus %s: unregistering\n", bus->name); |
| bus_remove_attrs(bus); |
| kset_unregister(&bus->drivers); |
| kset_unregister(&bus->devices); |
| subsystem_unregister(&bus->subsys); |
| } |
| |
| int __init buses_init(void) |
| { |
| return subsystem_register(&bus_subsys); |
| } |
| |
| |
| EXPORT_SYMBOL_GPL(bus_for_each_dev); |
| EXPORT_SYMBOL_GPL(bus_find_device); |
| EXPORT_SYMBOL_GPL(bus_for_each_drv); |
| |
| EXPORT_SYMBOL_GPL(bus_add_device); |
| EXPORT_SYMBOL_GPL(bus_attach_device); |
| EXPORT_SYMBOL_GPL(bus_remove_device); |
| EXPORT_SYMBOL_GPL(bus_register); |
| EXPORT_SYMBOL_GPL(bus_unregister); |
| EXPORT_SYMBOL_GPL(bus_rescan_devices); |
| EXPORT_SYMBOL_GPL(get_bus); |
| EXPORT_SYMBOL_GPL(put_bus); |
| EXPORT_SYMBOL_GPL(find_bus); |
| |
| EXPORT_SYMBOL_GPL(bus_create_file); |
| EXPORT_SYMBOL_GPL(bus_remove_file); |