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>
21 #include "power/power.h"
23 /* /sys/devices/system */
24 static struct kset *system_kset;
26 #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
29 * sysfs bindings for drivers
32 #define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
35 static int __must_check bus_rescan_devices_helper(struct device *dev,
38 static struct bus_type *bus_get(struct bus_type *bus)
41 kset_get(&bus->p->subsys);
47 static void bus_put(struct bus_type *bus)
50 kset_put(&bus->p->subsys);
53 static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr,
56 struct driver_attribute *drv_attr = to_drv_attr(attr);
57 struct driver_private *drv_priv = to_driver(kobj);
61 ret = drv_attr->show(drv_priv->driver, buf);
65 static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr,
66 const char *buf, size_t count)
68 struct driver_attribute *drv_attr = to_drv_attr(attr);
69 struct driver_private *drv_priv = to_driver(kobj);
73 ret = drv_attr->store(drv_priv->driver, buf, count);
77 static const struct sysfs_ops driver_sysfs_ops = {
78 .show = drv_attr_show,
79 .store = drv_attr_store,
82 static void driver_release(struct kobject *kobj)
84 struct driver_private *drv_priv = to_driver(kobj);
86 pr_debug("driver: '%s': %s\n", kobject_name(kobj), __func__);
90 static struct kobj_type driver_ktype = {
91 .sysfs_ops = &driver_sysfs_ops,
92 .release = driver_release,
96 * sysfs bindings for buses
98 static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr,
101 struct bus_attribute *bus_attr = to_bus_attr(attr);
102 struct subsys_private *subsys_priv = to_subsys_private(kobj);
106 ret = bus_attr->show(subsys_priv->bus, buf);
110 static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr,
111 const char *buf, size_t count)
113 struct bus_attribute *bus_attr = to_bus_attr(attr);
114 struct subsys_private *subsys_priv = to_subsys_private(kobj);
118 ret = bus_attr->store(subsys_priv->bus, buf, count);
122 static const struct sysfs_ops bus_sysfs_ops = {
123 .show = bus_attr_show,
124 .store = bus_attr_store,
127 int bus_create_file(struct bus_type *bus, struct bus_attribute *attr)
131 error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr);
137 EXPORT_SYMBOL_GPL(bus_create_file);
139 void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr)
142 sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr);
146 EXPORT_SYMBOL_GPL(bus_remove_file);
148 static struct kobj_type bus_ktype = {
149 .sysfs_ops = &bus_sysfs_ops,
152 static int bus_uevent_filter(struct kset *kset, struct kobject *kobj)
154 struct kobj_type *ktype = get_ktype(kobj);
156 if (ktype == &bus_ktype)
161 static const struct kset_uevent_ops bus_uevent_ops = {
162 .filter = bus_uevent_filter,
165 static struct kset *bus_kset;
167 /* Manually detach a device from its associated driver. */
168 static ssize_t unbind_store(struct device_driver *drv, const char *buf,
171 struct bus_type *bus = bus_get(drv->bus);
175 dev = bus_find_device_by_name(bus, NULL, buf);
176 if (dev && dev->driver == drv) {
177 if (dev->parent) /* Needed for USB */
178 device_lock(dev->parent);
179 device_release_driver(dev);
181 device_unlock(dev->parent);
188 static DRIVER_ATTR_WO(unbind);
191 * Manually attach a device to a driver.
192 * Note: the driver must want to bind to the device,
193 * it is not possible to override the driver's id table.
195 static ssize_t bind_store(struct device_driver *drv, const char *buf,
198 struct bus_type *bus = bus_get(drv->bus);
202 dev = bus_find_device_by_name(bus, NULL, buf);
203 if (dev && dev->driver == NULL && driver_match_device(drv, dev)) {
204 if (dev->parent) /* Needed for USB */
205 device_lock(dev->parent);
207 err = driver_probe_device(drv, dev);
210 device_unlock(dev->parent);
215 } else if (err == 0) {
216 /* driver didn't accept device */
224 static DRIVER_ATTR_WO(bind);
226 static ssize_t show_drivers_autoprobe(struct bus_type *bus, char *buf)
228 return sprintf(buf, "%d\n", bus->p->drivers_autoprobe);
231 static ssize_t store_drivers_autoprobe(struct bus_type *bus,
232 const char *buf, size_t count)
235 bus->p->drivers_autoprobe = 0;
237 bus->p->drivers_autoprobe = 1;
241 static ssize_t store_drivers_probe(struct bus_type *bus,
242 const char *buf, size_t count)
246 dev = bus_find_device_by_name(bus, NULL, buf);
249 if (bus_rescan_devices_helper(dev, NULL) != 0)
254 static struct device *next_device(struct klist_iter *i)
256 struct klist_node *n = klist_next(i);
257 struct device *dev = NULL;
258 struct device_private *dev_prv;
261 dev_prv = to_device_private_bus(n);
262 dev = dev_prv->device;
268 * bus_for_each_dev - device iterator.
270 * @start: device to start iterating from.
271 * @data: data for the callback.
272 * @fn: function to be called for each device.
274 * Iterate over @bus's list of devices, and call @fn for each,
275 * passing it @data. If @start is not NULL, we use that device to
276 * begin iterating from.
278 * We check the return of @fn each time. If it returns anything
279 * other than 0, we break out and return that value.
281 * NOTE: The device that returns a non-zero value is not retained
282 * in any way, nor is its refcount incremented. If the caller needs
283 * to retain this data, it should do so, and increment the reference
284 * count in the supplied callback.
286 int bus_for_each_dev(struct bus_type *bus, struct device *start,
287 void *data, int (*fn)(struct device *, void *))
296 klist_iter_init_node(&bus->p->klist_devices, &i,
297 (start ? &start->p->knode_bus : NULL));
298 while ((dev = next_device(&i)) && !error)
299 error = fn(dev, data);
303 EXPORT_SYMBOL_GPL(bus_for_each_dev);
306 * bus_find_device - device iterator for locating a particular device.
308 * @start: Device to begin with
309 * @data: Data to pass to match function
310 * @match: Callback function to check device
312 * This is similar to the bus_for_each_dev() function above, but it
313 * returns a reference to a device that is 'found' for later use, as
314 * determined by the @match callback.
316 * The callback should return 0 if the device doesn't match and non-zero
317 * if it does. If the callback returns non-zero, this function will
318 * return to the caller and not iterate over any more devices.
320 struct device *bus_find_device(struct bus_type *bus,
321 struct device *start, void *data,
322 int (*match)(struct device *dev, void *data))
330 klist_iter_init_node(&bus->p->klist_devices, &i,
331 (start ? &start->p->knode_bus : NULL));
332 while ((dev = next_device(&i)))
333 if (match(dev, data) && get_device(dev))
338 EXPORT_SYMBOL_GPL(bus_find_device);
340 static int match_name(struct device *dev, void *data)
342 const char *name = data;
344 return sysfs_streq(name, dev_name(dev));
348 * bus_find_device_by_name - device iterator for locating a particular device of a specific name
350 * @start: Device to begin with
351 * @name: name of the device to match
353 * This is similar to the bus_find_device() function above, but it handles
354 * searching by a name automatically, no need to write another strcmp matching
357 struct device *bus_find_device_by_name(struct bus_type *bus,
358 struct device *start, const char *name)
360 return bus_find_device(bus, start, (void *)name, match_name);
362 EXPORT_SYMBOL_GPL(bus_find_device_by_name);
365 * subsys_find_device_by_id - find a device with a specific enumeration number
367 * @id: index 'id' in struct device
368 * @hint: device to check first
370 * Check the hint's next object and if it is a match return it directly,
371 * otherwise, fall back to a full list search. Either way a reference for
372 * the returned object is taken.
374 struct device *subsys_find_device_by_id(struct bus_type *subsys, unsigned int id,
384 klist_iter_init_node(&subsys->p->klist_devices, &i, &hint->p->knode_bus);
385 dev = next_device(&i);
386 if (dev && dev->id == id && get_device(dev)) {
393 klist_iter_init_node(&subsys->p->klist_devices, &i, NULL);
394 while ((dev = next_device(&i))) {
395 if (dev->id == id && get_device(dev)) {
403 EXPORT_SYMBOL_GPL(subsys_find_device_by_id);
405 static struct device_driver *next_driver(struct klist_iter *i)
407 struct klist_node *n = klist_next(i);
408 struct driver_private *drv_priv;
411 drv_priv = container_of(n, struct driver_private, knode_bus);
412 return drv_priv->driver;
418 * bus_for_each_drv - driver iterator
419 * @bus: bus we're dealing with.
420 * @start: driver to start iterating on.
421 * @data: data to pass to the callback.
422 * @fn: function to call for each driver.
424 * This is nearly identical to the device iterator above.
425 * We iterate over each driver that belongs to @bus, and call
426 * @fn for each. If @fn returns anything but 0, we break out
427 * and return it. If @start is not NULL, we use it as the head
430 * NOTE: we don't return the driver that returns a non-zero
431 * value, nor do we leave the reference count incremented for that
432 * driver. If the caller needs to know that info, it must set it
433 * in the callback. It must also be sure to increment the refcount
434 * so it doesn't disappear before returning to the caller.
436 int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
437 void *data, int (*fn)(struct device_driver *, void *))
440 struct device_driver *drv;
446 klist_iter_init_node(&bus->p->klist_drivers, &i,
447 start ? &start->p->knode_bus : NULL);
448 while ((drv = next_driver(&i)) && !error)
449 error = fn(drv, data);
453 EXPORT_SYMBOL_GPL(bus_for_each_drv);
455 static int device_add_attrs(struct bus_type *bus, struct device *dev)
463 for (i = 0; bus->dev_attrs[i].attr.name; i++) {
464 error = device_create_file(dev, &bus->dev_attrs[i]);
467 device_remove_file(dev, &bus->dev_attrs[i]);
474 static void device_remove_attrs(struct bus_type *bus, struct device *dev)
478 if (bus->dev_attrs) {
479 for (i = 0; bus->dev_attrs[i].attr.name; i++)
480 device_remove_file(dev, &bus->dev_attrs[i]);
485 * bus_add_device - add device to bus
486 * @dev: device being added
488 * - Add device's bus attributes.
489 * - Create links to device's bus.
490 * - Add the device to its bus's list of devices.
492 int bus_add_device(struct device *dev)
494 struct bus_type *bus = bus_get(dev->bus);
498 pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev));
499 error = device_add_attrs(bus, dev);
502 error = device_add_groups(dev, bus->dev_groups);
505 error = sysfs_create_link(&bus->p->devices_kset->kobj,
506 &dev->kobj, dev_name(dev));
509 error = sysfs_create_link(&dev->kobj,
510 &dev->bus->p->subsys.kobj, "subsystem");
513 klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices);
518 sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev));
520 device_remove_groups(dev, bus->dev_groups);
522 device_remove_attrs(bus, dev);
529 * bus_probe_device - probe drivers for a new device
530 * @dev: device to probe
532 * - Automatically probe for a driver if the bus allows it.
534 void bus_probe_device(struct device *dev)
536 struct bus_type *bus = dev->bus;
537 struct subsys_interface *sif;
543 if (bus->p->drivers_autoprobe) {
544 ret = device_attach(dev);
548 mutex_lock(&bus->p->mutex);
549 list_for_each_entry(sif, &bus->p->interfaces, node)
551 sif->add_dev(dev, sif);
552 mutex_unlock(&bus->p->mutex);
556 * bus_remove_device - remove device from bus
557 * @dev: device to be removed
559 * - Remove device from all interfaces.
560 * - Remove symlink from bus' directory.
561 * - Delete device from bus's list.
562 * - Detach from its driver.
563 * - Drop reference taken in bus_add_device().
565 void bus_remove_device(struct device *dev)
567 struct bus_type *bus = dev->bus;
568 struct subsys_interface *sif;
573 mutex_lock(&bus->p->mutex);
574 list_for_each_entry(sif, &bus->p->interfaces, node)
576 sif->remove_dev(dev, sif);
577 mutex_unlock(&bus->p->mutex);
579 sysfs_remove_link(&dev->kobj, "subsystem");
580 sysfs_remove_link(&dev->bus->p->devices_kset->kobj,
582 device_remove_attrs(dev->bus, dev);
583 device_remove_groups(dev, dev->bus->dev_groups);
584 if (klist_node_attached(&dev->p->knode_bus))
585 klist_del(&dev->p->knode_bus);
587 pr_debug("bus: '%s': remove device %s\n",
588 dev->bus->name, dev_name(dev));
589 device_release_driver(dev);
593 static int driver_add_attrs(struct bus_type *bus, struct device_driver *drv)
598 if (bus->drv_attrs) {
599 for (i = 0; bus->drv_attrs[i].attr.name; i++) {
600 error = driver_create_file(drv, &bus->drv_attrs[i]);
609 driver_remove_file(drv, &bus->drv_attrs[i]);
613 static void driver_remove_attrs(struct bus_type *bus,
614 struct device_driver *drv)
618 if (bus->drv_attrs) {
619 for (i = 0; bus->drv_attrs[i].attr.name; i++)
620 driver_remove_file(drv, &bus->drv_attrs[i]);
624 static int __must_check add_bind_files(struct device_driver *drv)
628 ret = driver_create_file(drv, &driver_attr_unbind);
630 ret = driver_create_file(drv, &driver_attr_bind);
632 driver_remove_file(drv, &driver_attr_unbind);
637 static void remove_bind_files(struct device_driver *drv)
639 driver_remove_file(drv, &driver_attr_bind);
640 driver_remove_file(drv, &driver_attr_unbind);
643 static BUS_ATTR(drivers_probe, S_IWUSR, NULL, store_drivers_probe);
644 static BUS_ATTR(drivers_autoprobe, S_IWUSR | S_IRUGO,
645 show_drivers_autoprobe, store_drivers_autoprobe);
647 static int add_probe_files(struct bus_type *bus)
651 retval = bus_create_file(bus, &bus_attr_drivers_probe);
655 retval = bus_create_file(bus, &bus_attr_drivers_autoprobe);
657 bus_remove_file(bus, &bus_attr_drivers_probe);
662 static void remove_probe_files(struct bus_type *bus)
664 bus_remove_file(bus, &bus_attr_drivers_autoprobe);
665 bus_remove_file(bus, &bus_attr_drivers_probe);
668 static ssize_t uevent_store(struct device_driver *drv, const char *buf,
671 enum kobject_action action;
673 if (kobject_action_type(buf, count, &action) == 0)
674 kobject_uevent(&drv->p->kobj, action);
677 static DRIVER_ATTR_WO(uevent);
680 * bus_add_driver - Add a driver to the bus.
683 int bus_add_driver(struct device_driver *drv)
685 struct bus_type *bus;
686 struct driver_private *priv;
689 bus = bus_get(drv->bus);
693 pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name);
695 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
700 klist_init(&priv->klist_devices, NULL, NULL);
703 priv->kobj.kset = bus->p->drivers_kset;
704 error = kobject_init_and_add(&priv->kobj, &driver_ktype, NULL,
709 klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers);
710 if (drv->bus->p->drivers_autoprobe) {
711 error = driver_attach(drv);
715 module_add_driver(drv->owner, drv);
717 error = driver_create_file(drv, &driver_attr_uevent);
719 printk(KERN_ERR "%s: uevent attr (%s) failed\n",
720 __func__, drv->name);
722 error = driver_add_attrs(bus, drv);
724 /* How the hell do we get out of this pickle? Give up */
725 printk(KERN_ERR "%s: driver_add_attrs(%s) failed\n",
726 __func__, drv->name);
728 error = driver_add_groups(drv, bus->drv_groups);
730 printk(KERN_ERR "%s: driver_create_groups(%s) failed\n",
731 __func__, drv->name);
733 if (!drv->suppress_bind_attrs) {
734 error = add_bind_files(drv);
737 printk(KERN_ERR "%s: add_bind_files(%s) failed\n",
738 __func__, drv->name);
745 kobject_put(&priv->kobj);
754 * bus_remove_driver - delete driver from bus's knowledge.
757 * Detach the driver from the devices it controls, and remove
758 * it from its bus's list of drivers. Finally, we drop the reference
759 * to the bus we took in bus_add_driver().
761 void bus_remove_driver(struct device_driver *drv)
766 if (!drv->suppress_bind_attrs)
767 remove_bind_files(drv);
768 driver_remove_attrs(drv->bus, drv);
769 driver_remove_groups(drv, drv->bus->drv_groups);
770 driver_remove_file(drv, &driver_attr_uevent);
771 klist_remove(&drv->p->knode_bus);
772 pr_debug("bus: '%s': remove driver %s\n", drv->bus->name, drv->name);
774 module_remove_driver(drv);
775 kobject_put(&drv->p->kobj);
779 /* Helper for bus_rescan_devices's iter */
780 static int __must_check bus_rescan_devices_helper(struct device *dev,
786 if (dev->parent) /* Needed for USB */
787 device_lock(dev->parent);
788 ret = device_attach(dev);
790 device_unlock(dev->parent);
792 return ret < 0 ? ret : 0;
796 * bus_rescan_devices - rescan devices on the bus for possible drivers
797 * @bus: the bus to scan.
799 * This function will look for devices on the bus with no driver
800 * attached and rescan it against existing drivers to see if it matches
801 * any by calling device_attach() for the unbound devices.
803 int bus_rescan_devices(struct bus_type *bus)
805 return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
807 EXPORT_SYMBOL_GPL(bus_rescan_devices);
810 * device_reprobe - remove driver for a device and probe for a new driver
811 * @dev: the device to reprobe
813 * This function detaches the attached driver (if any) for the given
814 * device and restarts the driver probing process. It is intended
815 * to use if probing criteria changed during a devices lifetime and
816 * driver attachment should change accordingly.
818 int device_reprobe(struct device *dev)
821 if (dev->parent) /* Needed for USB */
822 device_lock(dev->parent);
823 device_release_driver(dev);
825 device_unlock(dev->parent);
827 return bus_rescan_devices_helper(dev, NULL);
829 EXPORT_SYMBOL_GPL(device_reprobe);
832 * find_bus - locate bus by name.
833 * @name: name of bus.
835 * Call kset_find_obj() to iterate over list of buses to
836 * find a bus by name. Return bus if found.
838 * Note that kset_find_obj increments bus' reference count.
841 struct bus_type *find_bus(char *name)
843 struct kobject *k = kset_find_obj(bus_kset, name);
844 return k ? to_bus(k) : NULL;
850 * bus_add_attrs - Add default attributes for this bus.
851 * @bus: Bus that has just been registered.
854 static int bus_add_attrs(struct bus_type *bus)
859 if (bus->bus_attrs) {
860 for (i = 0; bus->bus_attrs[i].attr.name; i++) {
861 error = bus_create_file(bus, &bus->bus_attrs[i]);
870 bus_remove_file(bus, &bus->bus_attrs[i]);
874 static void bus_remove_attrs(struct bus_type *bus)
878 if (bus->bus_attrs) {
879 for (i = 0; bus->bus_attrs[i].attr.name; i++)
880 bus_remove_file(bus, &bus->bus_attrs[i]);
884 static int bus_add_groups(struct bus_type *bus,
885 const struct attribute_group **groups)
887 return sysfs_create_groups(&bus->p->subsys.kobj, groups);
890 static void bus_remove_groups(struct bus_type *bus,
891 const struct attribute_group **groups)
893 sysfs_remove_groups(&bus->p->subsys.kobj, groups);
896 static void klist_devices_get(struct klist_node *n)
898 struct device_private *dev_prv = to_device_private_bus(n);
899 struct device *dev = dev_prv->device;
904 static void klist_devices_put(struct klist_node *n)
906 struct device_private *dev_prv = to_device_private_bus(n);
907 struct device *dev = dev_prv->device;
912 static ssize_t bus_uevent_store(struct bus_type *bus,
913 const char *buf, size_t count)
915 enum kobject_action action;
917 if (kobject_action_type(buf, count, &action) == 0)
918 kobject_uevent(&bus->p->subsys.kobj, action);
921 static BUS_ATTR(uevent, S_IWUSR, NULL, bus_uevent_store);
924 * bus_register - register a driver-core subsystem
925 * @bus: bus to register
927 * Once we have that, we register the bus with the kobject
928 * infrastructure, then register the children subsystems it has:
929 * the devices and drivers that belong to the subsystem.
931 int bus_register(struct bus_type *bus)
934 struct subsys_private *priv;
935 struct lock_class_key *key = &bus->lock_key;
937 priv = kzalloc(sizeof(struct subsys_private), GFP_KERNEL);
944 BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier);
946 retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name);
950 priv->subsys.kobj.kset = bus_kset;
951 priv->subsys.kobj.ktype = &bus_ktype;
952 priv->drivers_autoprobe = 1;
954 retval = kset_register(&priv->subsys);
958 retval = bus_create_file(bus, &bus_attr_uevent);
960 goto bus_uevent_fail;
962 priv->devices_kset = kset_create_and_add("devices", NULL,
964 if (!priv->devices_kset) {
966 goto bus_devices_fail;
969 priv->drivers_kset = kset_create_and_add("drivers", NULL,
971 if (!priv->drivers_kset) {
973 goto bus_drivers_fail;
976 INIT_LIST_HEAD(&priv->interfaces);
977 __mutex_init(&priv->mutex, "subsys mutex", key);
978 klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put);
979 klist_init(&priv->klist_drivers, NULL, NULL);
981 retval = add_probe_files(bus);
983 goto bus_probe_files_fail;
985 retval = bus_add_attrs(bus);
988 retval = bus_add_groups(bus, bus->bus_groups);
990 goto bus_groups_fail;
992 pr_debug("bus: '%s': registered\n", bus->name);
996 bus_remove_attrs(bus);
998 remove_probe_files(bus);
999 bus_probe_files_fail:
1000 kset_unregister(bus->p->drivers_kset);
1002 kset_unregister(bus->p->devices_kset);
1004 bus_remove_file(bus, &bus_attr_uevent);
1006 kset_unregister(&bus->p->subsys);
1012 EXPORT_SYMBOL_GPL(bus_register);
1015 * bus_unregister - remove a bus from the system
1018 * Unregister the child subsystems and the bus itself.
1019 * Finally, we call bus_put() to release the refcount
1021 void bus_unregister(struct bus_type *bus)
1023 pr_debug("bus: '%s': unregistering\n", bus->name);
1025 device_unregister(bus->dev_root);
1026 bus_remove_attrs(bus);
1027 bus_remove_groups(bus, bus->bus_groups);
1028 remove_probe_files(bus);
1029 kset_unregister(bus->p->drivers_kset);
1030 kset_unregister(bus->p->devices_kset);
1031 bus_remove_file(bus, &bus_attr_uevent);
1032 kset_unregister(&bus->p->subsys);
1036 EXPORT_SYMBOL_GPL(bus_unregister);
1038 int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
1040 return blocking_notifier_chain_register(&bus->p->bus_notifier, nb);
1042 EXPORT_SYMBOL_GPL(bus_register_notifier);
1044 int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
1046 return blocking_notifier_chain_unregister(&bus->p->bus_notifier, nb);
1048 EXPORT_SYMBOL_GPL(bus_unregister_notifier);
1050 struct kset *bus_get_kset(struct bus_type *bus)
1052 return &bus->p->subsys;
1054 EXPORT_SYMBOL_GPL(bus_get_kset);
1056 struct klist *bus_get_device_klist(struct bus_type *bus)
1058 return &bus->p->klist_devices;
1060 EXPORT_SYMBOL_GPL(bus_get_device_klist);
1063 * Yes, this forcibly breaks the klist abstraction temporarily. It
1064 * just wants to sort the klist, not change reference counts and
1065 * take/drop locks rapidly in the process. It does all this while
1066 * holding the lock for the list, so objects can't otherwise be
1067 * added/removed while we're swizzling.
1069 static void device_insertion_sort_klist(struct device *a, struct list_head *list,
1070 int (*compare)(const struct device *a,
1071 const struct device *b))
1073 struct list_head *pos;
1074 struct klist_node *n;
1075 struct device_private *dev_prv;
1078 list_for_each(pos, list) {
1079 n = container_of(pos, struct klist_node, n_node);
1080 dev_prv = to_device_private_bus(n);
1081 b = dev_prv->device;
1082 if (compare(a, b) <= 0) {
1083 list_move_tail(&a->p->knode_bus.n_node,
1084 &b->p->knode_bus.n_node);
1088 list_move_tail(&a->p->knode_bus.n_node, list);
1091 void bus_sort_breadthfirst(struct bus_type *bus,
1092 int (*compare)(const struct device *a,
1093 const struct device *b))
1095 LIST_HEAD(sorted_devices);
1096 struct list_head *pos, *tmp;
1097 struct klist_node *n;
1098 struct device_private *dev_prv;
1100 struct klist *device_klist;
1102 device_klist = bus_get_device_klist(bus);
1104 spin_lock(&device_klist->k_lock);
1105 list_for_each_safe(pos, tmp, &device_klist->k_list) {
1106 n = container_of(pos, struct klist_node, n_node);
1107 dev_prv = to_device_private_bus(n);
1108 dev = dev_prv->device;
1109 device_insertion_sort_klist(dev, &sorted_devices, compare);
1111 list_splice(&sorted_devices, &device_klist->k_list);
1112 spin_unlock(&device_klist->k_lock);
1114 EXPORT_SYMBOL_GPL(bus_sort_breadthfirst);
1117 * subsys_dev_iter_init - initialize subsys device iterator
1118 * @iter: subsys iterator to initialize
1119 * @subsys: the subsys we wanna iterate over
1120 * @start: the device to start iterating from, if any
1121 * @type: device_type of the devices to iterate over, NULL for all
1123 * Initialize subsys iterator @iter such that it iterates over devices
1124 * of @subsys. If @start is set, the list iteration will start there,
1125 * otherwise if it is NULL, the iteration starts at the beginning of
1128 void subsys_dev_iter_init(struct subsys_dev_iter *iter, struct bus_type *subsys,
1129 struct device *start, const struct device_type *type)
1131 struct klist_node *start_knode = NULL;
1134 start_knode = &start->p->knode_bus;
1135 klist_iter_init_node(&subsys->p->klist_devices, &iter->ki, start_knode);
1138 EXPORT_SYMBOL_GPL(subsys_dev_iter_init);
1141 * subsys_dev_iter_next - iterate to the next device
1142 * @iter: subsys iterator to proceed
1144 * Proceed @iter to the next device and return it. Returns NULL if
1145 * iteration is complete.
1147 * The returned device is referenced and won't be released till
1148 * iterator is proceed to the next device or exited. The caller is
1149 * free to do whatever it wants to do with the device including
1150 * calling back into subsys code.
1152 struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter)
1154 struct klist_node *knode;
1158 knode = klist_next(&iter->ki);
1161 dev = container_of(knode, struct device_private, knode_bus)->device;
1162 if (!iter->type || iter->type == dev->type)
1166 EXPORT_SYMBOL_GPL(subsys_dev_iter_next);
1169 * subsys_dev_iter_exit - finish iteration
1170 * @iter: subsys iterator to finish
1172 * Finish an iteration. Always call this function after iteration is
1173 * complete whether the iteration ran till the end or not.
1175 void subsys_dev_iter_exit(struct subsys_dev_iter *iter)
1177 klist_iter_exit(&iter->ki);
1179 EXPORT_SYMBOL_GPL(subsys_dev_iter_exit);
1181 int subsys_interface_register(struct subsys_interface *sif)
1183 struct bus_type *subsys;
1184 struct subsys_dev_iter iter;
1187 if (!sif || !sif->subsys)
1190 subsys = bus_get(sif->subsys);
1194 mutex_lock(&subsys->p->mutex);
1195 list_add_tail(&sif->node, &subsys->p->interfaces);
1197 subsys_dev_iter_init(&iter, subsys, NULL, NULL);
1198 while ((dev = subsys_dev_iter_next(&iter)))
1199 sif->add_dev(dev, sif);
1200 subsys_dev_iter_exit(&iter);
1202 mutex_unlock(&subsys->p->mutex);
1206 EXPORT_SYMBOL_GPL(subsys_interface_register);
1208 void subsys_interface_unregister(struct subsys_interface *sif)
1210 struct bus_type *subsys;
1211 struct subsys_dev_iter iter;
1214 if (!sif || !sif->subsys)
1217 subsys = sif->subsys;
1219 mutex_lock(&subsys->p->mutex);
1220 list_del_init(&sif->node);
1221 if (sif->remove_dev) {
1222 subsys_dev_iter_init(&iter, subsys, NULL, NULL);
1223 while ((dev = subsys_dev_iter_next(&iter)))
1224 sif->remove_dev(dev, sif);
1225 subsys_dev_iter_exit(&iter);
1227 mutex_unlock(&subsys->p->mutex);
1231 EXPORT_SYMBOL_GPL(subsys_interface_unregister);
1233 static void system_root_device_release(struct device *dev)
1238 static int subsys_register(struct bus_type *subsys,
1239 const struct attribute_group **groups,
1240 struct kobject *parent_of_root)
1245 err = bus_register(subsys);
1249 dev = kzalloc(sizeof(struct device), GFP_KERNEL);
1255 err = dev_set_name(dev, "%s", subsys->name);
1259 dev->kobj.parent = parent_of_root;
1260 dev->groups = groups;
1261 dev->release = system_root_device_release;
1263 err = device_register(dev);
1267 subsys->dev_root = dev;
1276 bus_unregister(subsys);
1281 * subsys_system_register - register a subsystem at /sys/devices/system/
1282 * @subsys: system subsystem
1283 * @groups: default attributes for the root device
1285 * All 'system' subsystems have a /sys/devices/system/<name> root device
1286 * with the name of the subsystem. The root device can carry subsystem-
1287 * wide attributes. All registered devices are below this single root
1288 * device and are named after the subsystem with a simple enumeration
1289 * number appended. The registered devices are not explicitely named;
1290 * only 'id' in the device needs to be set.
1292 * Do not use this interface for anything new, it exists for compatibility
1293 * with bad ideas only. New subsystems should use plain subsystems; and
1294 * add the subsystem-wide attributes should be added to the subsystem
1295 * directory itself and not some create fake root-device placed in
1296 * /sys/devices/system/<name>.
1298 int subsys_system_register(struct bus_type *subsys,
1299 const struct attribute_group **groups)
1301 return subsys_register(subsys, groups, &system_kset->kobj);
1303 EXPORT_SYMBOL_GPL(subsys_system_register);
1306 * subsys_virtual_register - register a subsystem at /sys/devices/virtual/
1307 * @subsys: virtual subsystem
1308 * @groups: default attributes for the root device
1310 * All 'virtual' subsystems have a /sys/devices/system/<name> root device
1311 * with the name of the subystem. The root device can carry subsystem-wide
1312 * attributes. All registered devices are below this single root device.
1313 * There's no restriction on device naming. This is for kernel software
1314 * constructs which need sysfs interface.
1316 int subsys_virtual_register(struct bus_type *subsys,
1317 const struct attribute_group **groups)
1319 struct kobject *virtual_dir;
1321 virtual_dir = virtual_device_parent(NULL);
1325 return subsys_register(subsys, groups, virtual_dir);
1327 EXPORT_SYMBOL_GPL(subsys_virtual_register);
1329 int __init buses_init(void)
1331 bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);
1335 system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj);