2 * bus.c - bus driver management
4 * Copyright (c) 2002-3 Patrick Mochel
5 * Copyright (c) 2002-3 Open Source Development Labs
6 * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de>
7 * Copyright (c) 2007 Novell Inc.
9 * This file is released under the GPLv2
13 #include <linux/device.h>
14 #include <linux/module.h>
15 #include <linux/errno.h>
16 #include <linux/slab.h>
17 #include <linux/init.h>
18 #include <linux/string.h>
19 #include <linux/mutex.h>
20 #include <linux/sysfs.h>
22 #include "power/power.h"
24 /* /sys/devices/system */
25 static struct kset *system_kset;
27 #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
30 * sysfs bindings for drivers
33 #define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
36 static int __must_check bus_rescan_devices_helper(struct device *dev,
39 static struct bus_type *bus_get(struct bus_type *bus)
42 kset_get(&bus->p->subsys);
48 static void bus_put(struct bus_type *bus)
51 kset_put(&bus->p->subsys);
54 static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr,
57 struct driver_attribute *drv_attr = to_drv_attr(attr);
58 struct driver_private *drv_priv = to_driver(kobj);
62 ret = drv_attr->show(drv_priv->driver, buf);
66 static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr,
67 const char *buf, size_t count)
69 struct driver_attribute *drv_attr = to_drv_attr(attr);
70 struct driver_private *drv_priv = to_driver(kobj);
74 ret = drv_attr->store(drv_priv->driver, buf, count);
78 static const struct sysfs_ops driver_sysfs_ops = {
79 .show = drv_attr_show,
80 .store = drv_attr_store,
83 static void driver_release(struct kobject *kobj)
85 struct driver_private *drv_priv = to_driver(kobj);
87 pr_debug("driver: '%s': %s\n", kobject_name(kobj), __func__);
91 static struct kobj_type driver_ktype = {
92 .sysfs_ops = &driver_sysfs_ops,
93 .release = driver_release,
97 * sysfs bindings for buses
99 static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr,
102 struct bus_attribute *bus_attr = to_bus_attr(attr);
103 struct subsys_private *subsys_priv = to_subsys_private(kobj);
107 ret = bus_attr->show(subsys_priv->bus, buf);
111 static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr,
112 const char *buf, size_t count)
114 struct bus_attribute *bus_attr = to_bus_attr(attr);
115 struct subsys_private *subsys_priv = to_subsys_private(kobj);
119 ret = bus_attr->store(subsys_priv->bus, buf, count);
123 static const struct sysfs_ops bus_sysfs_ops = {
124 .show = bus_attr_show,
125 .store = bus_attr_store,
128 int bus_create_file(struct bus_type *bus, struct bus_attribute *attr)
132 error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr);
138 EXPORT_SYMBOL_GPL(bus_create_file);
140 void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr)
143 sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr);
147 EXPORT_SYMBOL_GPL(bus_remove_file);
149 static struct kobj_type bus_ktype = {
150 .sysfs_ops = &bus_sysfs_ops,
153 static int bus_uevent_filter(struct kset *kset, struct kobject *kobj)
155 struct kobj_type *ktype = get_ktype(kobj);
157 if (ktype == &bus_ktype)
162 static const struct kset_uevent_ops bus_uevent_ops = {
163 .filter = bus_uevent_filter,
166 static struct kset *bus_kset;
168 /* Manually detach a device from its associated driver. */
169 static ssize_t unbind_store(struct device_driver *drv, const char *buf,
172 struct bus_type *bus = bus_get(drv->bus);
176 dev = bus_find_device_by_name(bus, NULL, buf);
177 if (dev && dev->driver == drv) {
178 if (dev->parent) /* Needed for USB */
179 device_lock(dev->parent);
180 device_release_driver(dev);
182 device_unlock(dev->parent);
189 static DRIVER_ATTR_WO(unbind);
192 * Manually attach a device to a driver.
193 * Note: the driver must want to bind to the device,
194 * it is not possible to override the driver's id table.
196 static ssize_t bind_store(struct device_driver *drv, const char *buf,
199 struct bus_type *bus = bus_get(drv->bus);
203 dev = bus_find_device_by_name(bus, NULL, buf);
204 if (dev && dev->driver == NULL && driver_match_device(drv, dev)) {
205 if (dev->parent) /* Needed for USB */
206 device_lock(dev->parent);
208 err = driver_probe_device(drv, dev);
211 device_unlock(dev->parent);
216 } else if (err == 0) {
217 /* driver didn't accept device */
225 static DRIVER_ATTR_WO(bind);
227 static ssize_t show_drivers_autoprobe(struct bus_type *bus, char *buf)
229 return sprintf(buf, "%d\n", bus->p->drivers_autoprobe);
232 static ssize_t store_drivers_autoprobe(struct bus_type *bus,
233 const char *buf, size_t count)
236 bus->p->drivers_autoprobe = 0;
238 bus->p->drivers_autoprobe = 1;
242 static ssize_t store_drivers_probe(struct bus_type *bus,
243 const char *buf, size_t count)
247 dev = bus_find_device_by_name(bus, NULL, buf);
250 if (bus_rescan_devices_helper(dev, NULL) != 0)
255 static struct device *next_device(struct klist_iter *i)
257 struct klist_node *n = klist_next(i);
258 struct device *dev = NULL;
259 struct device_private *dev_prv;
262 dev_prv = to_device_private_bus(n);
263 dev = dev_prv->device;
269 * bus_for_each_dev - device iterator.
271 * @start: device to start iterating from.
272 * @data: data for the callback.
273 * @fn: function to be called for each device.
275 * Iterate over @bus's list of devices, and call @fn for each,
276 * passing it @data. If @start is not NULL, we use that device to
277 * begin iterating from.
279 * We check the return of @fn each time. If it returns anything
280 * other than 0, we break out and return that value.
282 * NOTE: The device that returns a non-zero value is not retained
283 * in any way, nor is its refcount incremented. If the caller needs
284 * to retain this data, it should do so, and increment the reference
285 * count in the supplied callback.
287 int bus_for_each_dev(struct bus_type *bus, struct device *start,
288 void *data, int (*fn)(struct device *, void *))
297 klist_iter_init_node(&bus->p->klist_devices, &i,
298 (start ? &start->p->knode_bus : NULL));
299 while ((dev = next_device(&i)) && !error)
300 error = fn(dev, data);
304 EXPORT_SYMBOL_GPL(bus_for_each_dev);
307 * bus_find_device - device iterator for locating a particular device.
309 * @start: Device to begin with
310 * @data: Data to pass to match function
311 * @match: Callback function to check device
313 * This is similar to the bus_for_each_dev() function above, but it
314 * returns a reference to a device that is 'found' for later use, as
315 * determined by the @match callback.
317 * The callback should return 0 if the device doesn't match and non-zero
318 * if it does. If the callback returns non-zero, this function will
319 * return to the caller and not iterate over any more devices.
321 struct device *bus_find_device(struct bus_type *bus,
322 struct device *start, void *data,
323 int (*match)(struct device *dev, void *data))
331 klist_iter_init_node(&bus->p->klist_devices, &i,
332 (start ? &start->p->knode_bus : NULL));
333 while ((dev = next_device(&i)))
334 if (match(dev, data) && get_device(dev))
339 EXPORT_SYMBOL_GPL(bus_find_device);
341 static int match_name(struct device *dev, void *data)
343 const char *name = data;
345 return sysfs_streq(name, dev_name(dev));
349 * bus_find_device_by_name - device iterator for locating a particular device of a specific name
351 * @start: Device to begin with
352 * @name: name of the device to match
354 * This is similar to the bus_find_device() function above, but it handles
355 * searching by a name automatically, no need to write another strcmp matching
358 struct device *bus_find_device_by_name(struct bus_type *bus,
359 struct device *start, const char *name)
361 return bus_find_device(bus, start, (void *)name, match_name);
363 EXPORT_SYMBOL_GPL(bus_find_device_by_name);
366 * subsys_find_device_by_id - find a device with a specific enumeration number
368 * @id: index 'id' in struct device
369 * @hint: device to check first
371 * Check the hint's next object and if it is a match return it directly,
372 * otherwise, fall back to a full list search. Either way a reference for
373 * the returned object is taken.
375 struct device *subsys_find_device_by_id(struct bus_type *subsys, unsigned int id,
385 klist_iter_init_node(&subsys->p->klist_devices, &i, &hint->p->knode_bus);
386 dev = next_device(&i);
387 if (dev && dev->id == id && get_device(dev)) {
394 klist_iter_init_node(&subsys->p->klist_devices, &i, NULL);
395 while ((dev = next_device(&i))) {
396 if (dev->id == id && get_device(dev)) {
404 EXPORT_SYMBOL_GPL(subsys_find_device_by_id);
406 static struct device_driver *next_driver(struct klist_iter *i)
408 struct klist_node *n = klist_next(i);
409 struct driver_private *drv_priv;
412 drv_priv = container_of(n, struct driver_private, knode_bus);
413 return drv_priv->driver;
419 * bus_for_each_drv - driver iterator
420 * @bus: bus we're dealing with.
421 * @start: driver to start iterating on.
422 * @data: data to pass to the callback.
423 * @fn: function to call for each driver.
425 * This is nearly identical to the device iterator above.
426 * We iterate over each driver that belongs to @bus, and call
427 * @fn for each. If @fn returns anything but 0, we break out
428 * and return it. If @start is not NULL, we use it as the head
431 * NOTE: we don't return the driver that returns a non-zero
432 * value, nor do we leave the reference count incremented for that
433 * driver. If the caller needs to know that info, it must set it
434 * in the callback. It must also be sure to increment the refcount
435 * so it doesn't disappear before returning to the caller.
437 int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
438 void *data, int (*fn)(struct device_driver *, void *))
441 struct device_driver *drv;
447 klist_iter_init_node(&bus->p->klist_drivers, &i,
448 start ? &start->p->knode_bus : NULL);
449 while ((drv = next_driver(&i)) && !error)
450 error = fn(drv, data);
454 EXPORT_SYMBOL_GPL(bus_for_each_drv);
456 static int device_add_attrs(struct bus_type *bus, struct device *dev)
464 for (i = 0; bus->dev_attrs[i].attr.name; i++) {
465 error = device_create_file(dev, &bus->dev_attrs[i]);
468 device_remove_file(dev, &bus->dev_attrs[i]);
475 static void device_remove_attrs(struct bus_type *bus, struct device *dev)
479 if (bus->dev_attrs) {
480 for (i = 0; bus->dev_attrs[i].attr.name; i++)
481 device_remove_file(dev, &bus->dev_attrs[i]);
486 * bus_add_device - add device to bus
487 * @dev: device being added
489 * - Add device's bus attributes.
490 * - Create links to device's bus.
491 * - Add the device to its bus's list of devices.
493 int bus_add_device(struct device *dev)
495 struct bus_type *bus = bus_get(dev->bus);
499 pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev));
500 error = device_add_attrs(bus, dev);
503 error = device_add_groups(dev, bus->dev_groups);
506 error = sysfs_create_link(&bus->p->devices_kset->kobj,
507 &dev->kobj, dev_name(dev));
510 error = sysfs_create_link(&dev->kobj,
511 &dev->bus->p->subsys.kobj, "subsystem");
514 klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices);
519 sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev));
521 device_remove_groups(dev, bus->dev_groups);
523 device_remove_attrs(bus, dev);
530 * bus_probe_device - probe drivers for a new device
531 * @dev: device to probe
533 * - Automatically probe for a driver if the bus allows it.
535 void bus_probe_device(struct device *dev)
537 struct bus_type *bus = dev->bus;
538 struct subsys_interface *sif;
544 if (bus->p->drivers_autoprobe) {
545 ret = device_attach(dev);
549 mutex_lock(&bus->p->mutex);
550 list_for_each_entry(sif, &bus->p->interfaces, node)
552 sif->add_dev(dev, sif);
553 mutex_unlock(&bus->p->mutex);
557 * bus_remove_device - remove device from bus
558 * @dev: device to be removed
560 * - Remove device from all interfaces.
561 * - Remove symlink from bus' directory.
562 * - Delete device from bus's list.
563 * - Detach from its driver.
564 * - Drop reference taken in bus_add_device().
566 void bus_remove_device(struct device *dev)
568 struct bus_type *bus = dev->bus;
569 struct subsys_interface *sif;
574 mutex_lock(&bus->p->mutex);
575 list_for_each_entry(sif, &bus->p->interfaces, node)
577 sif->remove_dev(dev, sif);
578 mutex_unlock(&bus->p->mutex);
580 sysfs_remove_link(&dev->kobj, "subsystem");
581 sysfs_remove_link(&dev->bus->p->devices_kset->kobj,
583 device_remove_attrs(dev->bus, dev);
584 device_remove_groups(dev, dev->bus->dev_groups);
585 if (klist_node_attached(&dev->p->knode_bus))
586 klist_del(&dev->p->knode_bus);
588 pr_debug("bus: '%s': remove device %s\n",
589 dev->bus->name, dev_name(dev));
590 device_release_driver(dev);
594 static int driver_add_attrs(struct bus_type *bus, struct device_driver *drv)
599 if (bus->drv_attrs) {
600 for (i = 0; bus->drv_attrs[i].attr.name; i++) {
601 error = driver_create_file(drv, &bus->drv_attrs[i]);
610 driver_remove_file(drv, &bus->drv_attrs[i]);
614 static void driver_remove_attrs(struct bus_type *bus,
615 struct device_driver *drv)
619 if (bus->drv_attrs) {
620 for (i = 0; bus->drv_attrs[i].attr.name; i++)
621 driver_remove_file(drv, &bus->drv_attrs[i]);
625 static int __must_check add_bind_files(struct device_driver *drv)
629 ret = driver_create_file(drv, &driver_attr_unbind);
631 ret = driver_create_file(drv, &driver_attr_bind);
633 driver_remove_file(drv, &driver_attr_unbind);
638 static void remove_bind_files(struct device_driver *drv)
640 driver_remove_file(drv, &driver_attr_bind);
641 driver_remove_file(drv, &driver_attr_unbind);
644 static BUS_ATTR(drivers_probe, S_IWUSR, NULL, store_drivers_probe);
645 static BUS_ATTR(drivers_autoprobe, S_IWUSR | S_IRUGO,
646 show_drivers_autoprobe, store_drivers_autoprobe);
648 static int add_probe_files(struct bus_type *bus)
652 retval = bus_create_file(bus, &bus_attr_drivers_probe);
656 retval = bus_create_file(bus, &bus_attr_drivers_autoprobe);
658 bus_remove_file(bus, &bus_attr_drivers_probe);
663 static void remove_probe_files(struct bus_type *bus)
665 bus_remove_file(bus, &bus_attr_drivers_autoprobe);
666 bus_remove_file(bus, &bus_attr_drivers_probe);
669 static ssize_t uevent_store(struct device_driver *drv, const char *buf,
672 enum kobject_action action;
674 if (kobject_action_type(buf, count, &action) == 0)
675 kobject_uevent(&drv->p->kobj, action);
678 static DRIVER_ATTR_WO(uevent);
681 * bus_add_driver - Add a driver to the bus.
684 int bus_add_driver(struct device_driver *drv)
686 struct bus_type *bus;
687 struct driver_private *priv;
690 bus = bus_get(drv->bus);
694 pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name);
696 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
701 klist_init(&priv->klist_devices, NULL, NULL);
704 priv->kobj.kset = bus->p->drivers_kset;
705 error = kobject_init_and_add(&priv->kobj, &driver_ktype, NULL,
710 klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers);
711 if (drv->bus->p->drivers_autoprobe) {
712 error = driver_attach(drv);
716 module_add_driver(drv->owner, drv);
718 error = driver_create_file(drv, &driver_attr_uevent);
720 printk(KERN_ERR "%s: uevent attr (%s) failed\n",
721 __func__, drv->name);
723 error = driver_add_attrs(bus, drv);
725 /* How the hell do we get out of this pickle? Give up */
726 printk(KERN_ERR "%s: driver_add_attrs(%s) failed\n",
727 __func__, drv->name);
729 error = driver_add_groups(drv, bus->drv_groups);
731 printk(KERN_ERR "%s: driver_create_groups(%s) failed\n",
732 __func__, drv->name);
734 if (!drv->suppress_bind_attrs) {
735 error = add_bind_files(drv);
738 printk(KERN_ERR "%s: add_bind_files(%s) failed\n",
739 __func__, drv->name);
746 kobject_put(&priv->kobj);
755 * bus_remove_driver - delete driver from bus's knowledge.
758 * Detach the driver from the devices it controls, and remove
759 * it from its bus's list of drivers. Finally, we drop the reference
760 * to the bus we took in bus_add_driver().
762 void bus_remove_driver(struct device_driver *drv)
767 if (!drv->suppress_bind_attrs)
768 remove_bind_files(drv);
769 driver_remove_attrs(drv->bus, drv);
770 driver_remove_groups(drv, drv->bus->drv_groups);
771 driver_remove_file(drv, &driver_attr_uevent);
772 klist_remove(&drv->p->knode_bus);
773 pr_debug("bus: '%s': remove driver %s\n", drv->bus->name, drv->name);
775 module_remove_driver(drv);
776 kobject_put(&drv->p->kobj);
780 /* Helper for bus_rescan_devices's iter */
781 static int __must_check bus_rescan_devices_helper(struct device *dev,
787 if (dev->parent) /* Needed for USB */
788 device_lock(dev->parent);
789 ret = device_attach(dev);
791 device_unlock(dev->parent);
793 return ret < 0 ? ret : 0;
797 * bus_rescan_devices - rescan devices on the bus for possible drivers
798 * @bus: the bus to scan.
800 * This function will look for devices on the bus with no driver
801 * attached and rescan it against existing drivers to see if it matches
802 * any by calling device_attach() for the unbound devices.
804 int bus_rescan_devices(struct bus_type *bus)
806 return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
808 EXPORT_SYMBOL_GPL(bus_rescan_devices);
811 * device_reprobe - remove driver for a device and probe for a new driver
812 * @dev: the device to reprobe
814 * This function detaches the attached driver (if any) for the given
815 * device and restarts the driver probing process. It is intended
816 * to use if probing criteria changed during a devices lifetime and
817 * driver attachment should change accordingly.
819 int device_reprobe(struct device *dev)
822 if (dev->parent) /* Needed for USB */
823 device_lock(dev->parent);
824 device_release_driver(dev);
826 device_unlock(dev->parent);
828 return bus_rescan_devices_helper(dev, NULL);
830 EXPORT_SYMBOL_GPL(device_reprobe);
833 * find_bus - locate bus by name.
834 * @name: name of bus.
836 * Call kset_find_obj() to iterate over list of buses to
837 * find a bus by name. Return bus if found.
839 * Note that kset_find_obj increments bus' reference count.
842 struct bus_type *find_bus(char *name)
844 struct kobject *k = kset_find_obj(bus_kset, name);
845 return k ? to_bus(k) : NULL;
851 * bus_add_attrs - Add default attributes for this bus.
852 * @bus: Bus that has just been registered.
855 static int bus_add_attrs(struct bus_type *bus)
860 if (bus->bus_attrs) {
861 for (i = 0; bus->bus_attrs[i].attr.name; i++) {
862 error = bus_create_file(bus, &bus->bus_attrs[i]);
871 bus_remove_file(bus, &bus->bus_attrs[i]);
875 static void bus_remove_attrs(struct bus_type *bus)
879 if (bus->bus_attrs) {
880 for (i = 0; bus->bus_attrs[i].attr.name; i++)
881 bus_remove_file(bus, &bus->bus_attrs[i]);
885 static int bus_add_groups(struct bus_type *bus,
886 const struct attribute_group **groups)
888 return sysfs_create_groups(&bus->p->subsys.kobj, groups);
891 static void bus_remove_groups(struct bus_type *bus,
892 const struct attribute_group **groups)
894 sysfs_remove_groups(&bus->p->subsys.kobj, groups);
897 static void klist_devices_get(struct klist_node *n)
899 struct device_private *dev_prv = to_device_private_bus(n);
900 struct device *dev = dev_prv->device;
905 static void klist_devices_put(struct klist_node *n)
907 struct device_private *dev_prv = to_device_private_bus(n);
908 struct device *dev = dev_prv->device;
913 static ssize_t bus_uevent_store(struct bus_type *bus,
914 const char *buf, size_t count)
916 enum kobject_action action;
918 if (kobject_action_type(buf, count, &action) == 0)
919 kobject_uevent(&bus->p->subsys.kobj, action);
922 static BUS_ATTR(uevent, S_IWUSR, NULL, bus_uevent_store);
925 * bus_register - register a driver-core subsystem
926 * @bus: bus to register
928 * Once we have that, we register the bus with the kobject
929 * infrastructure, then register the children subsystems it has:
930 * the devices and drivers that belong to the subsystem.
932 int bus_register(struct bus_type *bus)
935 struct subsys_private *priv;
936 struct lock_class_key *key = &bus->lock_key;
938 priv = kzalloc(sizeof(struct subsys_private), GFP_KERNEL);
945 BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier);
947 retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name);
951 priv->subsys.kobj.kset = bus_kset;
952 priv->subsys.kobj.ktype = &bus_ktype;
953 priv->drivers_autoprobe = 1;
955 retval = kset_register(&priv->subsys);
959 retval = bus_create_file(bus, &bus_attr_uevent);
961 goto bus_uevent_fail;
963 priv->devices_kset = kset_create_and_add("devices", NULL,
965 if (!priv->devices_kset) {
967 goto bus_devices_fail;
970 priv->drivers_kset = kset_create_and_add("drivers", NULL,
972 if (!priv->drivers_kset) {
974 goto bus_drivers_fail;
977 INIT_LIST_HEAD(&priv->interfaces);
978 __mutex_init(&priv->mutex, "subsys mutex", key);
979 klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put);
980 klist_init(&priv->klist_drivers, NULL, NULL);
982 retval = add_probe_files(bus);
984 goto bus_probe_files_fail;
986 retval = bus_add_attrs(bus);
989 retval = bus_add_groups(bus, bus->bus_groups);
991 goto bus_groups_fail;
993 pr_debug("bus: '%s': registered\n", bus->name);
997 bus_remove_attrs(bus);
999 remove_probe_files(bus);
1000 bus_probe_files_fail:
1001 kset_unregister(bus->p->drivers_kset);
1003 kset_unregister(bus->p->devices_kset);
1005 bus_remove_file(bus, &bus_attr_uevent);
1007 kset_unregister(&bus->p->subsys);
1013 EXPORT_SYMBOL_GPL(bus_register);
1016 * bus_unregister - remove a bus from the system
1019 * Unregister the child subsystems and the bus itself.
1020 * Finally, we call bus_put() to release the refcount
1022 void bus_unregister(struct bus_type *bus)
1024 pr_debug("bus: '%s': unregistering\n", bus->name);
1026 device_unregister(bus->dev_root);
1027 bus_remove_attrs(bus);
1028 bus_remove_groups(bus, bus->bus_groups);
1029 remove_probe_files(bus);
1030 kset_unregister(bus->p->drivers_kset);
1031 kset_unregister(bus->p->devices_kset);
1032 bus_remove_file(bus, &bus_attr_uevent);
1033 kset_unregister(&bus->p->subsys);
1037 EXPORT_SYMBOL_GPL(bus_unregister);
1039 int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
1041 return blocking_notifier_chain_register(&bus->p->bus_notifier, nb);
1043 EXPORT_SYMBOL_GPL(bus_register_notifier);
1045 int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
1047 return blocking_notifier_chain_unregister(&bus->p->bus_notifier, nb);
1049 EXPORT_SYMBOL_GPL(bus_unregister_notifier);
1051 struct kset *bus_get_kset(struct bus_type *bus)
1053 return &bus->p->subsys;
1055 EXPORT_SYMBOL_GPL(bus_get_kset);
1057 struct klist *bus_get_device_klist(struct bus_type *bus)
1059 return &bus->p->klist_devices;
1061 EXPORT_SYMBOL_GPL(bus_get_device_klist);
1064 * Yes, this forcibly breaks the klist abstraction temporarily. It
1065 * just wants to sort the klist, not change reference counts and
1066 * take/drop locks rapidly in the process. It does all this while
1067 * holding the lock for the list, so objects can't otherwise be
1068 * added/removed while we're swizzling.
1070 static void device_insertion_sort_klist(struct device *a, struct list_head *list,
1071 int (*compare)(const struct device *a,
1072 const struct device *b))
1074 struct list_head *pos;
1075 struct klist_node *n;
1076 struct device_private *dev_prv;
1079 list_for_each(pos, list) {
1080 n = container_of(pos, struct klist_node, n_node);
1081 dev_prv = to_device_private_bus(n);
1082 b = dev_prv->device;
1083 if (compare(a, b) <= 0) {
1084 list_move_tail(&a->p->knode_bus.n_node,
1085 &b->p->knode_bus.n_node);
1089 list_move_tail(&a->p->knode_bus.n_node, list);
1092 void bus_sort_breadthfirst(struct bus_type *bus,
1093 int (*compare)(const struct device *a,
1094 const struct device *b))
1096 LIST_HEAD(sorted_devices);
1097 struct list_head *pos, *tmp;
1098 struct klist_node *n;
1099 struct device_private *dev_prv;
1101 struct klist *device_klist;
1103 device_klist = bus_get_device_klist(bus);
1105 spin_lock(&device_klist->k_lock);
1106 list_for_each_safe(pos, tmp, &device_klist->k_list) {
1107 n = container_of(pos, struct klist_node, n_node);
1108 dev_prv = to_device_private_bus(n);
1109 dev = dev_prv->device;
1110 device_insertion_sort_klist(dev, &sorted_devices, compare);
1112 list_splice(&sorted_devices, &device_klist->k_list);
1113 spin_unlock(&device_klist->k_lock);
1115 EXPORT_SYMBOL_GPL(bus_sort_breadthfirst);
1118 * subsys_dev_iter_init - initialize subsys device iterator
1119 * @iter: subsys iterator to initialize
1120 * @subsys: the subsys we wanna iterate over
1121 * @start: the device to start iterating from, if any
1122 * @type: device_type of the devices to iterate over, NULL for all
1124 * Initialize subsys iterator @iter such that it iterates over devices
1125 * of @subsys. If @start is set, the list iteration will start there,
1126 * otherwise if it is NULL, the iteration starts at the beginning of
1129 void subsys_dev_iter_init(struct subsys_dev_iter *iter, struct bus_type *subsys,
1130 struct device *start, const struct device_type *type)
1132 struct klist_node *start_knode = NULL;
1135 start_knode = &start->p->knode_bus;
1136 klist_iter_init_node(&subsys->p->klist_devices, &iter->ki, start_knode);
1139 EXPORT_SYMBOL_GPL(subsys_dev_iter_init);
1142 * subsys_dev_iter_next - iterate to the next device
1143 * @iter: subsys iterator to proceed
1145 * Proceed @iter to the next device and return it. Returns NULL if
1146 * iteration is complete.
1148 * The returned device is referenced and won't be released till
1149 * iterator is proceed to the next device or exited. The caller is
1150 * free to do whatever it wants to do with the device including
1151 * calling back into subsys code.
1153 struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter)
1155 struct klist_node *knode;
1159 knode = klist_next(&iter->ki);
1162 dev = container_of(knode, struct device_private, knode_bus)->device;
1163 if (!iter->type || iter->type == dev->type)
1167 EXPORT_SYMBOL_GPL(subsys_dev_iter_next);
1170 * subsys_dev_iter_exit - finish iteration
1171 * @iter: subsys iterator to finish
1173 * Finish an iteration. Always call this function after iteration is
1174 * complete whether the iteration ran till the end or not.
1176 void subsys_dev_iter_exit(struct subsys_dev_iter *iter)
1178 klist_iter_exit(&iter->ki);
1180 EXPORT_SYMBOL_GPL(subsys_dev_iter_exit);
1182 int subsys_interface_register(struct subsys_interface *sif)
1184 struct bus_type *subsys;
1185 struct subsys_dev_iter iter;
1188 if (!sif || !sif->subsys)
1191 subsys = bus_get(sif->subsys);
1195 mutex_lock(&subsys->p->mutex);
1196 list_add_tail(&sif->node, &subsys->p->interfaces);
1198 subsys_dev_iter_init(&iter, subsys, NULL, NULL);
1199 while ((dev = subsys_dev_iter_next(&iter)))
1200 sif->add_dev(dev, sif);
1201 subsys_dev_iter_exit(&iter);
1203 mutex_unlock(&subsys->p->mutex);
1207 EXPORT_SYMBOL_GPL(subsys_interface_register);
1209 void subsys_interface_unregister(struct subsys_interface *sif)
1211 struct bus_type *subsys;
1212 struct subsys_dev_iter iter;
1215 if (!sif || !sif->subsys)
1218 subsys = sif->subsys;
1220 mutex_lock(&subsys->p->mutex);
1221 list_del_init(&sif->node);
1222 if (sif->remove_dev) {
1223 subsys_dev_iter_init(&iter, subsys, NULL, NULL);
1224 while ((dev = subsys_dev_iter_next(&iter)))
1225 sif->remove_dev(dev, sif);
1226 subsys_dev_iter_exit(&iter);
1228 mutex_unlock(&subsys->p->mutex);
1232 EXPORT_SYMBOL_GPL(subsys_interface_unregister);
1234 static void system_root_device_release(struct device *dev)
1239 static int subsys_register(struct bus_type *subsys,
1240 const struct attribute_group **groups,
1241 struct kobject *parent_of_root)
1246 err = bus_register(subsys);
1250 dev = kzalloc(sizeof(struct device), GFP_KERNEL);
1256 err = dev_set_name(dev, "%s", subsys->name);
1260 dev->kobj.parent = parent_of_root;
1261 dev->groups = groups;
1262 dev->release = system_root_device_release;
1264 err = device_register(dev);
1268 subsys->dev_root = dev;
1277 bus_unregister(subsys);
1282 * subsys_system_register - register a subsystem at /sys/devices/system/
1283 * @subsys: system subsystem
1284 * @groups: default attributes for the root device
1286 * All 'system' subsystems have a /sys/devices/system/<name> root device
1287 * with the name of the subsystem. The root device can carry subsystem-
1288 * wide attributes. All registered devices are below this single root
1289 * device and are named after the subsystem with a simple enumeration
1290 * number appended. The registered devices are not explicitely named;
1291 * only 'id' in the device needs to be set.
1293 * Do not use this interface for anything new, it exists for compatibility
1294 * with bad ideas only. New subsystems should use plain subsystems; and
1295 * add the subsystem-wide attributes should be added to the subsystem
1296 * directory itself and not some create fake root-device placed in
1297 * /sys/devices/system/<name>.
1299 int subsys_system_register(struct bus_type *subsys,
1300 const struct attribute_group **groups)
1302 return subsys_register(subsys, groups, &system_kset->kobj);
1304 EXPORT_SYMBOL_GPL(subsys_system_register);
1307 * subsys_virtual_register - register a subsystem at /sys/devices/virtual/
1308 * @subsys: virtual subsystem
1309 * @groups: default attributes for the root device
1311 * All 'virtual' subsystems have a /sys/devices/system/<name> root device
1312 * with the name of the subystem. The root device can carry subsystem-wide
1313 * attributes. All registered devices are below this single root device.
1314 * There's no restriction on device naming. This is for kernel software
1315 * constructs which need sysfs interface.
1317 int subsys_virtual_register(struct bus_type *subsys,
1318 const struct attribute_group **groups)
1320 struct kobject *virtual_dir;
1322 virtual_dir = virtual_device_parent(NULL);
1326 return subsys_register(subsys, groups, virtual_dir);
1328 EXPORT_SYMBOL_GPL(subsys_virtual_register);
1330 int __init buses_init(void)
1332 bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);
1336 system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj);