3  * bus.c - bus driver management
12 #include <linux/device/bus.h>
42 static struct bus_type *bus_get(struct bus_type *bus)  in bus_get()  argument
44 	if (bus) {  in bus_get()
45 		kset_get(&bus->p->subsys);  in bus_get()
46 		return bus;  in bus_get()
51 static void bus_put(struct bus_type *bus)  in bus_put()  argument
53 	if (bus)  in bus_put()
54 		kset_put(&bus->p->subsys);  in bus_put()
110 		ret = bus_attr->show(subsys_priv->bus, buf);  in bus_attr_show()
122 		ret = bus_attr->store(subsys_priv->bus, buf, count);  in bus_attr_store()
131 int bus_create_file(struct bus_type *bus, struct bus_attribute *attr)  in bus_create_file()  argument
134 	if (bus_get(bus)) {  in bus_create_file()
135 		error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr);  in bus_create_file()
136 		bus_put(bus);  in bus_create_file()
143 void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr)  in bus_remove_file()  argument
145 	if (bus_get(bus)) {  in bus_remove_file()
146 		sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr);  in bus_remove_file()
147 		bus_put(bus);  in bus_remove_file()
155 	struct bus_type *bus = priv->bus;  in bus_release()  local
158 	bus->p = NULL;  in bus_release()
185 	struct bus_type *bus = bus_get(drv->bus);  in unbind_store()  local
189 	dev = bus_find_device_by_name(bus, NULL, buf);  in unbind_store()
195 	bus_put(bus);  in unbind_store()
208 	struct bus_type *bus = bus_get(drv->bus);  in bind_store()  local
212 	dev = bus_find_device_by_name(bus, NULL, buf);  in bind_store()
225 	bus_put(bus);  in bind_store()
230 static ssize_t drivers_autoprobe_show(struct bus_type *bus, char *buf)  in drivers_autoprobe_show()  argument
232 	return sysfs_emit(buf, "%d\n", bus->p->drivers_autoprobe);  in drivers_autoprobe_show()
235 static ssize_t drivers_autoprobe_store(struct bus_type *bus,  in drivers_autoprobe_store()  argument
239 		bus->p->drivers_autoprobe = 0;  in drivers_autoprobe_store()
241 		bus->p->drivers_autoprobe = 1;  in drivers_autoprobe_store()
245 static ssize_t drivers_probe_store(struct bus_type *bus,  in drivers_probe_store()  argument
251 	dev = bus_find_device_by_name(bus, NULL, buf);  in drivers_probe_store()
275  * @bus: bus type.
280  * Iterate over @bus's list of devices, and call @fn for each,
292 int bus_for_each_dev(struct bus_type *bus, struct device *start,  in bus_for_each_dev()  argument
299 	if (!bus || !bus->p)  in bus_for_each_dev()
302 	klist_iter_init_node(&bus->p->klist_devices, &i,  in bus_for_each_dev()
313  * @bus: bus type
326 struct device *bus_find_device(struct bus_type *bus,  in bus_find_device()  argument
333 	if (!bus || !bus->p)  in bus_find_device()
336 	klist_iter_init_node(&bus->p->klist_devices, &i,  in bus_find_device()
401  * @bus: bus we're dealing with.
407  * We iterate over each driver that belongs to @bus, and call
418 int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,  in bus_for_each_drv()  argument
425 	if (!bus)  in bus_for_each_drv()
428 	klist_iter_init_node(&bus->p->klist_drivers, &i,  in bus_for_each_drv()
438  * bus_add_device - add device to bus
441  * - Add device's bus attributes.
442  * - Create links to device's bus.
443  * - Add the device to its bus's list of devices.
447 	struct bus_type *bus = bus_get(dev->bus);  in bus_add_device()  local
450 	if (bus) {  in bus_add_device()
451 		pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev));  in bus_add_device()
452 		error = device_add_groups(dev, bus->dev_groups);  in bus_add_device()
455 		error = sysfs_create_link(&bus->p->devices_kset->kobj,  in bus_add_device()
460 				&dev->bus->p->subsys.kobj, "subsystem");  in bus_add_device()
463 		klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices);  in bus_add_device()
468 	sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev));  in bus_add_device()
470 	device_remove_groups(dev, bus->dev_groups);  in bus_add_device()
472 	bus_put(dev->bus);  in bus_add_device()
480  * - Automatically probe for a driver if the bus allows it.
484 	struct bus_type *bus = dev->bus;  in bus_probe_device()  local
487 	if (!bus)  in bus_probe_device()
490 	if (bus->p->drivers_autoprobe)  in bus_probe_device()
493 	mutex_lock(&bus->p->mutex);  in bus_probe_device()
494 	list_for_each_entry(sif, &bus->p->interfaces, node)  in bus_probe_device()
497 	mutex_unlock(&bus->p->mutex);  in bus_probe_device()
501  * bus_remove_device - remove device from bus
505  * - Remove symlink from bus' directory.
506  * - Delete device from bus's list.
512 	struct bus_type *bus = dev->bus;  in bus_remove_device()  local
515 	if (!bus)  in bus_remove_device()
518 	mutex_lock(&bus->p->mutex);  in bus_remove_device()
519 	list_for_each_entry(sif, &bus->p->interfaces, node)  in bus_remove_device()
522 	mutex_unlock(&bus->p->mutex);  in bus_remove_device()
525 	sysfs_remove_link(&dev->bus->p->devices_kset->kobj,  in bus_remove_device()
527 	device_remove_groups(dev, dev->bus->dev_groups);  in bus_remove_device()
531 	pr_debug("bus: '%s': remove device %s\n",  in bus_remove_device()
532 		 dev->bus->name, dev_name(dev));  in bus_remove_device()
534 	bus_put(dev->bus);  in bus_remove_device()
559 static int add_probe_files(struct bus_type *bus)  in add_probe_files()  argument
563 	retval = bus_create_file(bus, &bus_attr_drivers_probe);  in add_probe_files()
567 	retval = bus_create_file(bus, &bus_attr_drivers_autoprobe);  in add_probe_files()
569 		bus_remove_file(bus, &bus_attr_drivers_probe);  in add_probe_files()
574 static void remove_probe_files(struct bus_type *bus)  in remove_probe_files()  argument
576 	bus_remove_file(bus, &bus_attr_drivers_autoprobe);  in remove_probe_files()
577 	bus_remove_file(bus, &bus_attr_drivers_probe);  in remove_probe_files()
591  * bus_add_driver - Add a driver to the bus.
596 	struct bus_type *bus;  in bus_add_driver()  local
600 	bus = bus_get(drv->bus);  in bus_add_driver()
601 	if (!bus)  in bus_add_driver()
604 	pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name);  in bus_add_driver()
614 	priv->kobj.kset = bus->p->drivers_kset;  in bus_add_driver()
620 	klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers);  in bus_add_driver()
621 	if (drv->bus->p->drivers_autoprobe) {  in bus_add_driver()
633 	error = driver_add_groups(drv, bus->drv_groups);  in bus_add_driver()
656 	bus_put(bus);  in bus_add_driver()
661  * bus_remove_driver - delete driver from bus's knowledge.
665  * it from its bus's list of drivers. Finally, we drop the reference
666  * to the bus we took in bus_add_driver().
670 	if (!drv->bus)  in bus_remove_driver()
675 	driver_remove_groups(drv, drv->bus->drv_groups);  in bus_remove_driver()
678 	pr_debug("bus: '%s': remove driver %s\n", drv->bus->name, drv->name);  in bus_remove_driver()
682 	bus_put(drv->bus);  in bus_remove_driver()
692 		if (dev->parent && dev->bus->need_parent_lock)  in bus_rescan_devices_helper()
695 		if (dev->parent && dev->bus->need_parent_lock)  in bus_rescan_devices_helper()
702  * bus_rescan_devices - rescan devices on the bus for possible drivers
703  * @bus: the bus to scan.
705  * This function will look for devices on the bus with no driver
709 int bus_rescan_devices(struct bus_type *bus)  in bus_rescan_devices()  argument
711 	return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);  in bus_rescan_devices()
733  * find_bus - locate bus by name.
734  * @name: name of bus.
737  * find a bus by name. Return bus if found.
739  * Note that kset_find_obj increments bus' reference count.
749 static int bus_add_groups(struct bus_type *bus,  in bus_add_groups()  argument
752 	return sysfs_create_groups(&bus->p->subsys.kobj, groups);  in bus_add_groups()
755 static void bus_remove_groups(struct bus_type *bus,  in bus_remove_groups()  argument
758 	sysfs_remove_groups(&bus->p->subsys.kobj, groups);  in bus_remove_groups()
777 static ssize_t bus_uevent_store(struct bus_type *bus,  in bus_uevent_store()  argument
782 	rc = kobject_synth_uevent(&bus->p->subsys.kobj, buf, count);  in bus_uevent_store()
796  * @bus: bus to register
798  * Once we have that, we register the bus with the kobject
802 int bus_register(struct bus_type *bus)  in bus_register()  argument
806 	struct lock_class_key *key = &bus->lock_key;  in bus_register()
812 	priv->bus = bus;  in bus_register()
813 	bus->p = priv;  in bus_register()
817 	retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name);  in bus_register()
829 	retval = bus_create_file(bus, &bus_attr_uevent);  in bus_register()
852 	retval = add_probe_files(bus);  in bus_register()
856 	retval = bus_add_groups(bus, bus->bus_groups);  in bus_register()
860 	pr_debug("bus: '%s': registered\n", bus->name);  in bus_register()
864 	remove_probe_files(bus);  in bus_register()
866 	kset_unregister(bus->p->drivers_kset);  in bus_register()
868 	kset_unregister(bus->p->devices_kset);  in bus_register()
870 	bus_remove_file(bus, &bus_attr_uevent);  in bus_register()
872 	kset_unregister(&bus->p->subsys);  in bus_register()
874 	kfree(bus->p);  in bus_register()
875 	bus->p = NULL;  in bus_register()
881  * bus_unregister - remove a bus from the system
882  * @bus: bus.
884  * Unregister the child subsystems and the bus itself.
887 void bus_unregister(struct bus_type *bus)  in bus_unregister()  argument
889 	pr_debug("bus: '%s': unregistering\n", bus->name);  in bus_unregister()
890 	if (bus->dev_root)  in bus_unregister()
891 		device_unregister(bus->dev_root);  in bus_unregister()
892 	bus_remove_groups(bus, bus->bus_groups);  in bus_unregister()
893 	remove_probe_files(bus);  in bus_unregister()
894 	kset_unregister(bus->p->drivers_kset);  in bus_unregister()
895 	kset_unregister(bus->p->devices_kset);  in bus_unregister()
896 	bus_remove_file(bus, &bus_attr_uevent);  in bus_unregister()
897 	kset_unregister(&bus->p->subsys);  in bus_unregister()
901 int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)  in bus_register_notifier()  argument
903 	return blocking_notifier_chain_register(&bus->p->bus_notifier, nb);  in bus_register_notifier()
907 int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)  in bus_unregister_notifier()  argument
909 	return blocking_notifier_chain_unregister(&bus->p->bus_notifier, nb);  in bus_unregister_notifier()
913 struct kset *bus_get_kset(struct bus_type *bus)  in bus_get_kset()  argument
915 	return &bus->p->subsys;  in bus_get_kset()
919 struct klist *bus_get_device_klist(struct bus_type *bus)  in bus_get_device_klist()  argument
921 	return &bus->p->klist_devices;  in bus_get_device_klist()
952 void bus_sort_breadthfirst(struct bus_type *bus,  in bus_sort_breadthfirst()  argument
962 	device_klist = bus_get_device_klist(bus);  in bus_sort_breadthfirst()
1190 	bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);  in buses_init()