2 * bus.c - bus driver management
4 * Copyright (c) 2002-3 Patrick Mochel
5 * Copyright (c) 2002-3 Open Source Development Labs
7 * This file is released under the GPLv2
11 #include <linux/config.h>
12 #include <linux/device.h>
13 #include <linux/module.h>
14 #include <linux/errno.h>
15 #include <linux/init.h>
16 #include <linux/string.h>
18 #include "power/power.h"
20 #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
21 #define to_bus(obj) container_of(obj, struct bus_type, subsys.kset.kobj)
24 * sysfs bindings for drivers
27 #define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
28 #define to_driver(obj) container_of(obj, struct device_driver, kobj)
32 drv_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
34 struct driver_attribute * drv_attr = to_drv_attr(attr);
35 struct device_driver * drv = to_driver(kobj);
39 ret = drv_attr->show(drv, buf);
44 drv_attr_store(struct kobject * kobj, struct attribute * attr,
45 const char * buf, size_t count)
47 struct driver_attribute * drv_attr = to_drv_attr(attr);
48 struct device_driver * drv = to_driver(kobj);
52 ret = drv_attr->store(drv, buf, count);
56 static struct sysfs_ops driver_sysfs_ops = {
57 .show = drv_attr_show,
58 .store = drv_attr_store,
62 static void driver_release(struct kobject * kobj)
64 struct device_driver * drv = to_driver(kobj);
65 complete(&drv->unloaded);
68 static struct kobj_type ktype_driver = {
69 .sysfs_ops = &driver_sysfs_ops,
70 .release = driver_release,
75 * sysfs bindings for buses
80 bus_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
82 struct bus_attribute * bus_attr = to_bus_attr(attr);
83 struct bus_type * bus = to_bus(kobj);
87 ret = bus_attr->show(bus, buf);
92 bus_attr_store(struct kobject * kobj, struct attribute * attr,
93 const char * buf, size_t count)
95 struct bus_attribute * bus_attr = to_bus_attr(attr);
96 struct bus_type * bus = to_bus(kobj);
100 ret = bus_attr->store(bus, buf, count);
104 static struct sysfs_ops bus_sysfs_ops = {
105 .show = bus_attr_show,
106 .store = bus_attr_store,
109 int bus_create_file(struct bus_type * bus, struct bus_attribute * attr)
113 error = sysfs_create_file(&bus->subsys.kset.kobj, &attr->attr);
120 void bus_remove_file(struct bus_type * bus, struct bus_attribute * attr)
123 sysfs_remove_file(&bus->subsys.kset.kobj, &attr->attr);
128 static struct kobj_type ktype_bus = {
129 .sysfs_ops = &bus_sysfs_ops,
133 decl_subsys(bus, &ktype_bus, NULL);
136 static struct device * next_device(struct klist_iter * i)
138 struct klist_node * n = klist_next(i);
139 return n ? container_of(n, struct device, knode_bus) : NULL;
143 * bus_for_each_dev - device iterator.
145 * @start: device to start iterating from.
146 * @data: data for the callback.
147 * @fn: function to be called for each device.
149 * Iterate over @bus's list of devices, and call @fn for each,
150 * passing it @data. If @start is not NULL, we use that device to
151 * begin iterating from.
153 * We check the return of @fn each time. If it returns anything
154 * other than 0, we break out and return that value.
156 * NOTE: The device that returns a non-zero value is not retained
157 * in any way, nor is its refcount incremented. If the caller needs
158 * to retain this data, it should do, and increment the reference
159 * count in the supplied callback.
162 int bus_for_each_dev(struct bus_type * bus, struct device * start,
163 void * data, int (*fn)(struct device *, void *))
172 klist_iter_init_node(&bus->klist_devices, &i,
173 (start ? &start->knode_bus : NULL));
174 while ((dev = next_device(&i)) && !error)
175 error = fn(dev, data);
182 static struct device_driver * next_driver(struct klist_iter * i)
184 struct klist_node * n = klist_next(i);
185 return n ? container_of(n, struct device_driver, knode_bus) : NULL;
189 * bus_for_each_drv - driver iterator
190 * @bus: bus we're dealing with.
191 * @start: driver to start iterating on.
192 * @data: data to pass to the callback.
193 * @fn: function to call for each driver.
195 * This is nearly identical to the device iterator above.
196 * We iterate over each driver that belongs to @bus, and call
197 * @fn for each. If @fn returns anything but 0, we break out
198 * and return it. If @start is not NULL, we use it as the head
201 * NOTE: we don't return the driver that returns a non-zero
202 * value, nor do we leave the reference count incremented for that
203 * driver. If the caller needs to know that info, it must set it
204 * in the callback. It must also be sure to increment the refcount
205 * so it doesn't disappear before returning to the caller.
208 int bus_for_each_drv(struct bus_type * bus, struct device_driver * start,
209 void * data, int (*fn)(struct device_driver *, void *))
212 struct device_driver * drv;
218 klist_iter_init_node(&bus->klist_drivers, &i,
219 start ? &start->knode_bus : NULL);
220 while ((drv = next_driver(&i)) && !error)
221 error = fn(drv, data);
226 static int device_add_attrs(struct bus_type * bus, struct device * dev)
231 if (bus->dev_attrs) {
232 for (i = 0; attr_name(bus->dev_attrs[i]); i++) {
233 error = device_create_file(dev,&bus->dev_attrs[i]);
242 device_remove_file(dev,&bus->dev_attrs[i]);
247 static void device_remove_attrs(struct bus_type * bus, struct device * dev)
251 if (bus->dev_attrs) {
252 for (i = 0; attr_name(bus->dev_attrs[i]); i++)
253 device_remove_file(dev,&bus->dev_attrs[i]);
259 * bus_add_device - add device to bus
260 * @dev: device being added
262 * - Add the device to its bus's list of devices.
263 * - Try to attach to driver.
264 * - Create link to device's physical location.
266 int bus_add_device(struct device * dev)
268 struct bus_type * bus = get_bus(dev->bus);
272 pr_debug("bus %s: add device %s\n", bus->name, dev->bus_id);
274 klist_add_tail(&bus->klist_devices, &dev->knode_bus);
275 device_add_attrs(bus, dev);
276 sysfs_create_link(&bus->devices.kobj, &dev->kobj, dev->bus_id);
277 sysfs_create_link(&dev->kobj, &dev->bus->subsys.kset.kobj, "bus");
283 * bus_remove_device - remove device from bus
284 * @dev: device to be removed
286 * - Remove symlink from bus's directory.
287 * - Delete device from bus's list.
288 * - Detach from its driver.
289 * - Drop reference taken in bus_add_device().
291 void bus_remove_device(struct device * dev)
294 sysfs_remove_link(&dev->kobj, "bus");
295 sysfs_remove_link(&dev->bus->devices.kobj, dev->bus_id);
296 device_remove_attrs(dev->bus, dev);
297 klist_remove(&dev->knode_bus);
298 pr_debug("bus %s: remove device %s\n", dev->bus->name, dev->bus_id);
299 device_release_driver(dev);
304 static int driver_add_attrs(struct bus_type * bus, struct device_driver * drv)
309 if (bus->drv_attrs) {
310 for (i = 0; attr_name(bus->drv_attrs[i]); i++) {
311 error = driver_create_file(drv, &bus->drv_attrs[i]);
320 driver_remove_file(drv, &bus->drv_attrs[i]);
325 static void driver_remove_attrs(struct bus_type * bus, struct device_driver * drv)
329 if (bus->drv_attrs) {
330 for (i = 0; attr_name(bus->drv_attrs[i]); i++)
331 driver_remove_file(drv, &bus->drv_attrs[i]);
337 * bus_add_driver - Add a driver to the bus.
341 int bus_add_driver(struct device_driver * drv)
343 struct bus_type * bus = get_bus(drv->bus);
347 pr_debug("bus %s: add driver %s\n", bus->name, drv->name);
348 error = kobject_set_name(&drv->kobj, "%s", drv->name);
353 drv->kobj.kset = &bus->drivers;
354 if ((error = kobject_register(&drv->kobj))) {
360 klist_add_tail(&bus->klist_drivers, &drv->knode_bus);
361 module_add_driver(drv->owner, drv);
363 driver_add_attrs(bus, drv);
370 * bus_remove_driver - delete driver from bus's knowledge.
373 * Detach the driver from the devices it controls, and remove
374 * it from its bus's list of drivers. Finally, we drop the reference
375 * to the bus we took in bus_add_driver().
378 void bus_remove_driver(struct device_driver * drv)
381 driver_remove_attrs(drv->bus, drv);
382 klist_remove(&drv->knode_bus);
383 pr_debug("bus %s: remove driver %s\n", drv->bus->name, drv->name);
385 module_remove_driver(drv);
386 kobject_unregister(&drv->kobj);
392 /* Helper for bus_rescan_devices's iter */
393 static int bus_rescan_devices_helper(struct device *dev, void *data)
397 if (!dev->driver && device_attach(dev))
405 * bus_rescan_devices - rescan devices on the bus for possible drivers
406 * @bus: the bus to scan.
408 * This function will look for devices on the bus with no driver
409 * attached and rescan it against existing drivers to see if it
410 * matches any. Calls device_attach(). Returns the number of devices
411 * that were sucessfully bound to a driver.
413 int bus_rescan_devices(struct bus_type * bus)
417 bus_for_each_dev(bus, NULL, &count, bus_rescan_devices_helper);
423 struct bus_type * get_bus(struct bus_type * bus)
425 return bus ? container_of(subsys_get(&bus->subsys), struct bus_type, subsys) : NULL;
428 void put_bus(struct bus_type * bus)
430 subsys_put(&bus->subsys);
435 * find_bus - locate bus by name.
436 * @name: name of bus.
438 * Call kset_find_obj() to iterate over list of buses to
439 * find a bus by name. Return bus if found.
441 * Note that kset_find_obj increments bus' reference count.
444 struct bus_type * find_bus(char * name)
446 struct kobject * k = kset_find_obj(&bus_subsys.kset, name);
447 return k ? to_bus(k) : NULL;
452 * bus_add_attrs - Add default attributes for this bus.
453 * @bus: Bus that has just been registered.
456 static int bus_add_attrs(struct bus_type * bus)
461 if (bus->bus_attrs) {
462 for (i = 0; attr_name(bus->bus_attrs[i]); i++) {
463 if ((error = bus_create_file(bus,&bus->bus_attrs[i])))
471 bus_remove_file(bus,&bus->bus_attrs[i]);
475 static void bus_remove_attrs(struct bus_type * bus)
479 if (bus->bus_attrs) {
480 for (i = 0; attr_name(bus->bus_attrs[i]); i++)
481 bus_remove_file(bus,&bus->bus_attrs[i]);
486 * bus_register - register a bus with the system.
489 * Once we have that, we registered the bus with the kobject
490 * infrastructure, then register the children subsystems it has:
491 * the devices and drivers that belong to the bus.
493 int bus_register(struct bus_type * bus)
497 retval = kobject_set_name(&bus->subsys.kset.kobj, "%s", bus->name);
501 subsys_set_kset(bus, bus_subsys);
502 retval = subsystem_register(&bus->subsys);
506 kobject_set_name(&bus->devices.kobj, "devices");
507 bus->devices.subsys = &bus->subsys;
508 retval = kset_register(&bus->devices);
510 goto bus_devices_fail;
512 kobject_set_name(&bus->drivers.kobj, "drivers");
513 bus->drivers.subsys = &bus->subsys;
514 bus->drivers.ktype = &ktype_driver;
515 retval = kset_register(&bus->drivers);
517 goto bus_drivers_fail;
519 klist_init(&bus->klist_devices);
520 klist_init(&bus->klist_drivers);
523 pr_debug("bus type '%s' registered\n", bus->name);
527 kset_unregister(&bus->devices);
529 subsystem_unregister(&bus->subsys);
536 * bus_unregister - remove a bus from the system
539 * Unregister the child subsystems and the bus itself.
540 * Finally, we call put_bus() to release the refcount
542 void bus_unregister(struct bus_type * bus)
544 pr_debug("bus %s: unregistering\n", bus->name);
545 bus_remove_attrs(bus);
546 kset_unregister(&bus->drivers);
547 kset_unregister(&bus->devices);
548 subsystem_unregister(&bus->subsys);
551 int __init buses_init(void)
553 return subsystem_register(&bus_subsys);
557 EXPORT_SYMBOL_GPL(bus_for_each_dev);
558 EXPORT_SYMBOL_GPL(bus_for_each_drv);
560 EXPORT_SYMBOL_GPL(bus_add_device);
561 EXPORT_SYMBOL_GPL(bus_remove_device);
562 EXPORT_SYMBOL_GPL(bus_register);
563 EXPORT_SYMBOL_GPL(bus_unregister);
564 EXPORT_SYMBOL_GPL(bus_rescan_devices);
565 EXPORT_SYMBOL_GPL(get_bus);
566 EXPORT_SYMBOL_GPL(put_bus);
567 EXPORT_SYMBOL_GPL(find_bus);
569 EXPORT_SYMBOL_GPL(bus_create_file);
570 EXPORT_SYMBOL_GPL(bus_remove_file);