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/async.h>
14 #include <linux/device.h>
15 #include <linux/module.h>
16 #include <linux/errno.h>
17 #include <linux/slab.h>
18 #include <linux/init.h>
19 #include <linux/string.h>
20 #include <linux/mutex.h>
21 #include <linux/sysfs.h>
23 #include "power/power.h"
25 /* /sys/devices/system */
26 static struct kset *system_kset;
28 #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
31 * sysfs bindings for drivers
34 #define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
37 static int __must_check bus_rescan_devices_helper(struct device *dev,
40 static struct bus_type *bus_get(struct bus_type *bus)
43 kset_get(&bus->p->subsys);
49 static void bus_put(struct bus_type *bus)
52 kset_put(&bus->p->subsys);
55 static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr,
58 struct driver_attribute *drv_attr = to_drv_attr(attr);
59 struct driver_private *drv_priv = to_driver(kobj);
63 ret = drv_attr->show(drv_priv->driver, buf);
67 static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr,
68 const char *buf, size_t count)
70 struct driver_attribute *drv_attr = to_drv_attr(attr);
71 struct driver_private *drv_priv = to_driver(kobj);
75 ret = drv_attr->store(drv_priv->driver, buf, count);
79 static const struct sysfs_ops driver_sysfs_ops = {
80 .show = drv_attr_show,
81 .store = drv_attr_store,
84 static void driver_release(struct kobject *kobj)
86 struct driver_private *drv_priv = to_driver(kobj);
88 pr_debug("driver: '%s': %s\n", kobject_name(kobj), __func__);
92 static struct kobj_type driver_ktype = {
93 .sysfs_ops = &driver_sysfs_ops,
94 .release = driver_release,
98 * sysfs bindings for buses
100 static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr,
103 struct bus_attribute *bus_attr = to_bus_attr(attr);
104 struct subsys_private *subsys_priv = to_subsys_private(kobj);
108 ret = bus_attr->show(subsys_priv->bus, buf);
112 static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr,
113 const char *buf, size_t count)
115 struct bus_attribute *bus_attr = to_bus_attr(attr);
116 struct subsys_private *subsys_priv = to_subsys_private(kobj);
120 ret = bus_attr->store(subsys_priv->bus, buf, count);
124 static const struct sysfs_ops bus_sysfs_ops = {
125 .show = bus_attr_show,
126 .store = bus_attr_store,
129 int bus_create_file(struct bus_type *bus, struct bus_attribute *attr)
133 error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr);
139 EXPORT_SYMBOL_GPL(bus_create_file);
141 void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr)
144 sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr);
148 EXPORT_SYMBOL_GPL(bus_remove_file);
150 static void bus_release(struct kobject *kobj)
152 struct subsys_private *priv =
153 container_of(kobj, typeof(*priv), subsys.kobj);
154 struct bus_type *bus = priv->bus;
160 static struct kobj_type bus_ktype = {
161 .sysfs_ops = &bus_sysfs_ops,
162 .release = bus_release,
165 static int bus_uevent_filter(struct kset *kset, struct kobject *kobj)
167 struct kobj_type *ktype = get_ktype(kobj);
169 if (ktype == &bus_ktype)
174 static const struct kset_uevent_ops bus_uevent_ops = {
175 .filter = bus_uevent_filter,
178 static struct kset *bus_kset;
180 /* Manually detach a device from its associated driver. */
181 static ssize_t unbind_store(struct device_driver *drv, const char *buf,
184 struct bus_type *bus = bus_get(drv->bus);
188 dev = bus_find_device_by_name(bus, NULL, buf);
189 if (dev && dev->driver == drv) {
190 if (dev->parent) /* Needed for USB */
191 device_lock(dev->parent);
192 device_release_driver(dev);
194 device_unlock(dev->parent);
201 static DRIVER_ATTR_WO(unbind);
204 * Manually attach a device to a driver.
205 * Note: the driver must want to bind to the device,
206 * it is not possible to override the driver's id table.
208 static ssize_t bind_store(struct device_driver *drv, const char *buf,
211 struct bus_type *bus = bus_get(drv->bus);
215 dev = bus_find_device_by_name(bus, NULL, buf);
216 if (dev && dev->driver == NULL && driver_match_device(drv, dev)) {
217 if (dev->parent) /* Needed for USB */
218 device_lock(dev->parent);
220 err = driver_probe_device(drv, dev);
223 device_unlock(dev->parent);
228 } else if (err == 0) {
229 /* driver didn't accept device */
237 static DRIVER_ATTR_WO(bind);
239 static ssize_t show_drivers_autoprobe(struct bus_type *bus, char *buf)
241 return sprintf(buf, "%d\n", bus->p->drivers_autoprobe);
244 static ssize_t store_drivers_autoprobe(struct bus_type *bus,
245 const char *buf, size_t count)
248 bus->p->drivers_autoprobe = 0;
250 bus->p->drivers_autoprobe = 1;
254 static ssize_t store_drivers_probe(struct bus_type *bus,
255 const char *buf, size_t count)
260 dev = bus_find_device_by_name(bus, NULL, buf);
263 if (bus_rescan_devices_helper(dev, NULL) == 0)
269 static struct device *next_device(struct klist_iter *i)
271 struct klist_node *n = klist_next(i);
272 struct device *dev = NULL;
273 struct device_private *dev_prv;
276 dev_prv = to_device_private_bus(n);
277 dev = dev_prv->device;
283 * bus_for_each_dev - device iterator.
285 * @start: device to start iterating from.
286 * @data: data for the callback.
287 * @fn: function to be called for each device.
289 * Iterate over @bus's list of devices, and call @fn for each,
290 * passing it @data. If @start is not NULL, we use that device to
291 * begin iterating from.
293 * We check the return of @fn each time. If it returns anything
294 * other than 0, we break out and return that value.
296 * NOTE: The device that returns a non-zero value is not retained
297 * in any way, nor is its refcount incremented. If the caller needs
298 * to retain this data, it should do so, and increment the reference
299 * count in the supplied callback.
301 int bus_for_each_dev(struct bus_type *bus, struct device *start,
302 void *data, int (*fn)(struct device *, void *))
311 klist_iter_init_node(&bus->p->klist_devices, &i,
312 (start ? &start->p->knode_bus : NULL));
313 while ((dev = next_device(&i)) && !error)
314 error = fn(dev, data);
318 EXPORT_SYMBOL_GPL(bus_for_each_dev);
321 * bus_find_device - device iterator for locating a particular device.
323 * @start: Device to begin with
324 * @data: Data to pass to match function
325 * @match: Callback function to check device
327 * This is similar to the bus_for_each_dev() function above, but it
328 * returns a reference to a device that is 'found' for later use, as
329 * determined by the @match callback.
331 * The callback should return 0 if the device doesn't match and non-zero
332 * if it does. If the callback returns non-zero, this function will
333 * return to the caller and not iterate over any more devices.
335 struct device *bus_find_device(struct bus_type *bus,
336 struct device *start, void *data,
337 int (*match)(struct device *dev, void *data))
345 klist_iter_init_node(&bus->p->klist_devices, &i,
346 (start ? &start->p->knode_bus : NULL));
347 while ((dev = next_device(&i)))
348 if (match(dev, data) && get_device(dev))
353 EXPORT_SYMBOL_GPL(bus_find_device);
355 static int match_name(struct device *dev, void *data)
357 const char *name = data;
359 return sysfs_streq(name, dev_name(dev));
363 * bus_find_device_by_name - device iterator for locating a particular device of a specific name
365 * @start: Device to begin with
366 * @name: name of the device to match
368 * This is similar to the bus_find_device() function above, but it handles
369 * searching by a name automatically, no need to write another strcmp matching
372 struct device *bus_find_device_by_name(struct bus_type *bus,
373 struct device *start, const char *name)
375 return bus_find_device(bus, start, (void *)name, match_name);
377 EXPORT_SYMBOL_GPL(bus_find_device_by_name);
380 * subsys_find_device_by_id - find a device with a specific enumeration number
382 * @id: index 'id' in struct device
383 * @hint: device to check first
385 * Check the hint's next object and if it is a match return it directly,
386 * otherwise, fall back to a full list search. Either way a reference for
387 * the returned object is taken.
389 struct device *subsys_find_device_by_id(struct bus_type *subsys, unsigned int id,
399 klist_iter_init_node(&subsys->p->klist_devices, &i, &hint->p->knode_bus);
400 dev = next_device(&i);
401 if (dev && dev->id == id && get_device(dev)) {
408 klist_iter_init_node(&subsys->p->klist_devices, &i, NULL);
409 while ((dev = next_device(&i))) {
410 if (dev->id == id && get_device(dev)) {
418 EXPORT_SYMBOL_GPL(subsys_find_device_by_id);
420 static struct device_driver *next_driver(struct klist_iter *i)
422 struct klist_node *n = klist_next(i);
423 struct driver_private *drv_priv;
426 drv_priv = container_of(n, struct driver_private, knode_bus);
427 return drv_priv->driver;
433 * bus_for_each_drv - driver iterator
434 * @bus: bus we're dealing with.
435 * @start: driver to start iterating on.
436 * @data: data to pass to the callback.
437 * @fn: function to call for each driver.
439 * This is nearly identical to the device iterator above.
440 * We iterate over each driver that belongs to @bus, and call
441 * @fn for each. If @fn returns anything but 0, we break out
442 * and return it. If @start is not NULL, we use it as the head
445 * NOTE: we don't return the driver that returns a non-zero
446 * value, nor do we leave the reference count incremented for that
447 * driver. If the caller needs to know that info, it must set it
448 * in the callback. It must also be sure to increment the refcount
449 * so it doesn't disappear before returning to the caller.
451 int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
452 void *data, int (*fn)(struct device_driver *, void *))
455 struct device_driver *drv;
461 klist_iter_init_node(&bus->p->klist_drivers, &i,
462 start ? &start->p->knode_bus : NULL);
463 while ((drv = next_driver(&i)) && !error)
464 error = fn(drv, data);
468 EXPORT_SYMBOL_GPL(bus_for_each_drv);
470 static int device_add_attrs(struct bus_type *bus, struct device *dev)
478 for (i = 0; bus->dev_attrs[i].attr.name; i++) {
479 error = device_create_file(dev, &bus->dev_attrs[i]);
482 device_remove_file(dev, &bus->dev_attrs[i]);
489 static void device_remove_attrs(struct bus_type *bus, struct device *dev)
493 if (bus->dev_attrs) {
494 for (i = 0; bus->dev_attrs[i].attr.name; i++)
495 device_remove_file(dev, &bus->dev_attrs[i]);
500 * bus_add_device - add device to bus
501 * @dev: device being added
503 * - Add device's bus attributes.
504 * - Create links to device's bus.
505 * - Add the device to its bus's list of devices.
507 int bus_add_device(struct device *dev)
509 struct bus_type *bus = bus_get(dev->bus);
513 pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev));
514 error = device_add_attrs(bus, dev);
517 error = device_add_groups(dev, bus->dev_groups);
520 error = sysfs_create_link(&bus->p->devices_kset->kobj,
521 &dev->kobj, dev_name(dev));
524 error = sysfs_create_link(&dev->kobj,
525 &dev->bus->p->subsys.kobj, "subsystem");
528 klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices);
533 sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev));
535 device_remove_groups(dev, bus->dev_groups);
537 device_remove_attrs(bus, dev);
544 * bus_probe_device - probe drivers for a new device
545 * @dev: device to probe
547 * - Automatically probe for a driver if the bus allows it.
549 void bus_probe_device(struct device *dev)
551 struct bus_type *bus = dev->bus;
552 struct subsys_interface *sif;
557 if (bus->p->drivers_autoprobe)
558 device_initial_probe(dev);
560 mutex_lock(&bus->p->mutex);
561 list_for_each_entry(sif, &bus->p->interfaces, node)
563 sif->add_dev(dev, sif);
564 mutex_unlock(&bus->p->mutex);
568 * bus_remove_device - remove device from bus
569 * @dev: device to be removed
571 * - Remove device from all interfaces.
572 * - Remove symlink from bus' directory.
573 * - Delete device from bus's list.
574 * - Detach from its driver.
575 * - Drop reference taken in bus_add_device().
577 void bus_remove_device(struct device *dev)
579 struct bus_type *bus = dev->bus;
580 struct subsys_interface *sif;
585 mutex_lock(&bus->p->mutex);
586 list_for_each_entry(sif, &bus->p->interfaces, node)
588 sif->remove_dev(dev, sif);
589 mutex_unlock(&bus->p->mutex);
591 sysfs_remove_link(&dev->kobj, "subsystem");
592 sysfs_remove_link(&dev->bus->p->devices_kset->kobj,
594 device_remove_attrs(dev->bus, dev);
595 device_remove_groups(dev, dev->bus->dev_groups);
596 if (klist_node_attached(&dev->p->knode_bus))
597 klist_del(&dev->p->knode_bus);
599 pr_debug("bus: '%s': remove device %s\n",
600 dev->bus->name, dev_name(dev));
601 device_release_driver(dev);
605 static int __must_check add_bind_files(struct device_driver *drv)
609 ret = driver_create_file(drv, &driver_attr_unbind);
611 ret = driver_create_file(drv, &driver_attr_bind);
613 driver_remove_file(drv, &driver_attr_unbind);
618 static void remove_bind_files(struct device_driver *drv)
620 driver_remove_file(drv, &driver_attr_bind);
621 driver_remove_file(drv, &driver_attr_unbind);
624 static BUS_ATTR(drivers_probe, S_IWUSR, NULL, store_drivers_probe);
625 static BUS_ATTR(drivers_autoprobe, S_IWUSR | S_IRUGO,
626 show_drivers_autoprobe, store_drivers_autoprobe);
628 static int add_probe_files(struct bus_type *bus)
632 retval = bus_create_file(bus, &bus_attr_drivers_probe);
636 retval = bus_create_file(bus, &bus_attr_drivers_autoprobe);
638 bus_remove_file(bus, &bus_attr_drivers_probe);
643 static void remove_probe_files(struct bus_type *bus)
645 bus_remove_file(bus, &bus_attr_drivers_autoprobe);
646 bus_remove_file(bus, &bus_attr_drivers_probe);
649 static ssize_t uevent_store(struct device_driver *drv, const char *buf,
652 enum kobject_action action;
654 if (kobject_action_type(buf, count, &action) == 0)
655 kobject_uevent(&drv->p->kobj, action);
658 static DRIVER_ATTR_WO(uevent);
660 static void driver_attach_async(void *_drv, async_cookie_t cookie)
662 struct device_driver *drv = _drv;
665 ret = driver_attach(drv);
667 pr_debug("bus: '%s': driver %s async attach completed: %d\n",
668 drv->bus->name, drv->name, ret);
672 * bus_add_driver - Add a driver to the bus.
675 int bus_add_driver(struct device_driver *drv)
677 struct bus_type *bus;
678 struct driver_private *priv;
681 bus = bus_get(drv->bus);
685 pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name);
687 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
692 klist_init(&priv->klist_devices, NULL, NULL);
695 priv->kobj.kset = bus->p->drivers_kset;
696 error = kobject_init_and_add(&priv->kobj, &driver_ktype, NULL,
701 klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers);
702 if (drv->bus->p->drivers_autoprobe) {
703 if (driver_allows_async_probing(drv)) {
704 pr_debug("bus: '%s': probing driver %s asynchronously\n",
705 drv->bus->name, drv->name);
706 async_schedule(driver_attach_async, drv);
708 error = driver_attach(drv);
713 module_add_driver(drv->owner, drv);
715 error = driver_create_file(drv, &driver_attr_uevent);
717 printk(KERN_ERR "%s: uevent attr (%s) failed\n",
718 __func__, drv->name);
720 error = driver_add_groups(drv, bus->drv_groups);
722 /* How the hell do we get out of this pickle? Give up */
723 printk(KERN_ERR "%s: driver_create_groups(%s) failed\n",
724 __func__, drv->name);
727 if (!drv->suppress_bind_attrs) {
728 error = add_bind_files(drv);
731 printk(KERN_ERR "%s: add_bind_files(%s) failed\n",
732 __func__, drv->name);
739 kobject_put(&priv->kobj);
748 * bus_remove_driver - delete driver from bus's knowledge.
751 * Detach the driver from the devices it controls, and remove
752 * it from its bus's list of drivers. Finally, we drop the reference
753 * to the bus we took in bus_add_driver().
755 void bus_remove_driver(struct device_driver *drv)
760 if (!drv->suppress_bind_attrs)
761 remove_bind_files(drv);
762 driver_remove_groups(drv, drv->bus->drv_groups);
763 driver_remove_file(drv, &driver_attr_uevent);
764 klist_remove(&drv->p->knode_bus);
765 pr_debug("bus: '%s': remove driver %s\n", drv->bus->name, drv->name);
767 module_remove_driver(drv);
768 kobject_put(&drv->p->kobj);
772 /* Helper for bus_rescan_devices's iter */
773 static int __must_check bus_rescan_devices_helper(struct device *dev,
779 if (dev->parent) /* Needed for USB */
780 device_lock(dev->parent);
781 ret = device_attach(dev);
783 device_unlock(dev->parent);
785 return ret < 0 ? ret : 0;
789 * bus_rescan_devices - rescan devices on the bus for possible drivers
790 * @bus: the bus to scan.
792 * This function will look for devices on the bus with no driver
793 * attached and rescan it against existing drivers to see if it matches
794 * any by calling device_attach() for the unbound devices.
796 int bus_rescan_devices(struct bus_type *bus)
798 return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
800 EXPORT_SYMBOL_GPL(bus_rescan_devices);
803 * device_reprobe - remove driver for a device and probe for a new driver
804 * @dev: the device to reprobe
806 * This function detaches the attached driver (if any) for the given
807 * device and restarts the driver probing process. It is intended
808 * to use if probing criteria changed during a devices lifetime and
809 * driver attachment should change accordingly.
811 int device_reprobe(struct device *dev)
814 if (dev->parent) /* Needed for USB */
815 device_lock(dev->parent);
816 device_release_driver(dev);
818 device_unlock(dev->parent);
820 return bus_rescan_devices_helper(dev, NULL);
822 EXPORT_SYMBOL_GPL(device_reprobe);
825 * find_bus - locate bus by name.
826 * @name: name of bus.
828 * Call kset_find_obj() to iterate over list of buses to
829 * find a bus by name. Return bus if found.
831 * Note that kset_find_obj increments bus' reference count.
834 struct bus_type *find_bus(char *name)
836 struct kobject *k = kset_find_obj(bus_kset, name);
837 return k ? to_bus(k) : NULL;
841 static int bus_add_groups(struct bus_type *bus,
842 const struct attribute_group **groups)
844 return sysfs_create_groups(&bus->p->subsys.kobj, groups);
847 static void bus_remove_groups(struct bus_type *bus,
848 const struct attribute_group **groups)
850 sysfs_remove_groups(&bus->p->subsys.kobj, groups);
853 static void klist_devices_get(struct klist_node *n)
855 struct device_private *dev_prv = to_device_private_bus(n);
856 struct device *dev = dev_prv->device;
861 static void klist_devices_put(struct klist_node *n)
863 struct device_private *dev_prv = to_device_private_bus(n);
864 struct device *dev = dev_prv->device;
869 static ssize_t bus_uevent_store(struct bus_type *bus,
870 const char *buf, size_t count)
872 enum kobject_action action;
874 if (kobject_action_type(buf, count, &action) == 0)
875 kobject_uevent(&bus->p->subsys.kobj, action);
878 static BUS_ATTR(uevent, S_IWUSR, NULL, bus_uevent_store);
881 * bus_register - register a driver-core subsystem
882 * @bus: bus to register
884 * Once we have that, we register the bus with the kobject
885 * infrastructure, then register the children subsystems it has:
886 * the devices and drivers that belong to the subsystem.
888 int bus_register(struct bus_type *bus)
891 struct subsys_private *priv;
892 struct lock_class_key *key = &bus->lock_key;
894 priv = kzalloc(sizeof(struct subsys_private), GFP_KERNEL);
901 BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier);
903 retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name);
907 priv->subsys.kobj.kset = bus_kset;
908 priv->subsys.kobj.ktype = &bus_ktype;
909 priv->drivers_autoprobe = 1;
911 retval = kset_register(&priv->subsys);
915 retval = bus_create_file(bus, &bus_attr_uevent);
917 goto bus_uevent_fail;
919 priv->devices_kset = kset_create_and_add("devices", NULL,
921 if (!priv->devices_kset) {
923 goto bus_devices_fail;
926 priv->drivers_kset = kset_create_and_add("drivers", NULL,
928 if (!priv->drivers_kset) {
930 goto bus_drivers_fail;
933 INIT_LIST_HEAD(&priv->interfaces);
934 __mutex_init(&priv->mutex, "subsys mutex", key);
935 klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put);
936 klist_init(&priv->klist_drivers, NULL, NULL);
938 retval = add_probe_files(bus);
940 goto bus_probe_files_fail;
942 retval = bus_add_groups(bus, bus->bus_groups);
944 goto bus_groups_fail;
946 pr_debug("bus: '%s': registered\n", bus->name);
950 remove_probe_files(bus);
951 bus_probe_files_fail:
952 kset_unregister(bus->p->drivers_kset);
954 kset_unregister(bus->p->devices_kset);
956 bus_remove_file(bus, &bus_attr_uevent);
958 kset_unregister(&bus->p->subsys);
964 EXPORT_SYMBOL_GPL(bus_register);
967 * bus_unregister - remove a bus from the system
970 * Unregister the child subsystems and the bus itself.
971 * Finally, we call bus_put() to release the refcount
973 void bus_unregister(struct bus_type *bus)
975 pr_debug("bus: '%s': unregistering\n", bus->name);
977 device_unregister(bus->dev_root);
978 bus_remove_groups(bus, bus->bus_groups);
979 remove_probe_files(bus);
980 kset_unregister(bus->p->drivers_kset);
981 kset_unregister(bus->p->devices_kset);
982 bus_remove_file(bus, &bus_attr_uevent);
983 kset_unregister(&bus->p->subsys);
985 EXPORT_SYMBOL_GPL(bus_unregister);
987 int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
989 return blocking_notifier_chain_register(&bus->p->bus_notifier, nb);
991 EXPORT_SYMBOL_GPL(bus_register_notifier);
993 int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
995 return blocking_notifier_chain_unregister(&bus->p->bus_notifier, nb);
997 EXPORT_SYMBOL_GPL(bus_unregister_notifier);
999 struct kset *bus_get_kset(struct bus_type *bus)
1001 return &bus->p->subsys;
1003 EXPORT_SYMBOL_GPL(bus_get_kset);
1005 struct klist *bus_get_device_klist(struct bus_type *bus)
1007 return &bus->p->klist_devices;
1009 EXPORT_SYMBOL_GPL(bus_get_device_klist);
1012 * Yes, this forcibly breaks the klist abstraction temporarily. It
1013 * just wants to sort the klist, not change reference counts and
1014 * take/drop locks rapidly in the process. It does all this while
1015 * holding the lock for the list, so objects can't otherwise be
1016 * added/removed while we're swizzling.
1018 static void device_insertion_sort_klist(struct device *a, struct list_head *list,
1019 int (*compare)(const struct device *a,
1020 const struct device *b))
1022 struct list_head *pos;
1023 struct klist_node *n;
1024 struct device_private *dev_prv;
1027 list_for_each(pos, list) {
1028 n = container_of(pos, struct klist_node, n_node);
1029 dev_prv = to_device_private_bus(n);
1030 b = dev_prv->device;
1031 if (compare(a, b) <= 0) {
1032 list_move_tail(&a->p->knode_bus.n_node,
1033 &b->p->knode_bus.n_node);
1037 list_move_tail(&a->p->knode_bus.n_node, list);
1040 void bus_sort_breadthfirst(struct bus_type *bus,
1041 int (*compare)(const struct device *a,
1042 const struct device *b))
1044 LIST_HEAD(sorted_devices);
1045 struct list_head *pos, *tmp;
1046 struct klist_node *n;
1047 struct device_private *dev_prv;
1049 struct klist *device_klist;
1051 device_klist = bus_get_device_klist(bus);
1053 spin_lock(&device_klist->k_lock);
1054 list_for_each_safe(pos, tmp, &device_klist->k_list) {
1055 n = container_of(pos, struct klist_node, n_node);
1056 dev_prv = to_device_private_bus(n);
1057 dev = dev_prv->device;
1058 device_insertion_sort_klist(dev, &sorted_devices, compare);
1060 list_splice(&sorted_devices, &device_klist->k_list);
1061 spin_unlock(&device_klist->k_lock);
1063 EXPORT_SYMBOL_GPL(bus_sort_breadthfirst);
1066 * subsys_dev_iter_init - initialize subsys device iterator
1067 * @iter: subsys iterator to initialize
1068 * @subsys: the subsys we wanna iterate over
1069 * @start: the device to start iterating from, if any
1070 * @type: device_type of the devices to iterate over, NULL for all
1072 * Initialize subsys iterator @iter such that it iterates over devices
1073 * of @subsys. If @start is set, the list iteration will start there,
1074 * otherwise if it is NULL, the iteration starts at the beginning of
1077 void subsys_dev_iter_init(struct subsys_dev_iter *iter, struct bus_type *subsys,
1078 struct device *start, const struct device_type *type)
1080 struct klist_node *start_knode = NULL;
1083 start_knode = &start->p->knode_bus;
1084 klist_iter_init_node(&subsys->p->klist_devices, &iter->ki, start_knode);
1087 EXPORT_SYMBOL_GPL(subsys_dev_iter_init);
1090 * subsys_dev_iter_next - iterate to the next device
1091 * @iter: subsys iterator to proceed
1093 * Proceed @iter to the next device and return it. Returns NULL if
1094 * iteration is complete.
1096 * The returned device is referenced and won't be released till
1097 * iterator is proceed to the next device or exited. The caller is
1098 * free to do whatever it wants to do with the device including
1099 * calling back into subsys code.
1101 struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter)
1103 struct klist_node *knode;
1107 knode = klist_next(&iter->ki);
1110 dev = container_of(knode, struct device_private, knode_bus)->device;
1111 if (!iter->type || iter->type == dev->type)
1115 EXPORT_SYMBOL_GPL(subsys_dev_iter_next);
1118 * subsys_dev_iter_exit - finish iteration
1119 * @iter: subsys iterator to finish
1121 * Finish an iteration. Always call this function after iteration is
1122 * complete whether the iteration ran till the end or not.
1124 void subsys_dev_iter_exit(struct subsys_dev_iter *iter)
1126 klist_iter_exit(&iter->ki);
1128 EXPORT_SYMBOL_GPL(subsys_dev_iter_exit);
1130 int subsys_interface_register(struct subsys_interface *sif)
1132 struct bus_type *subsys;
1133 struct subsys_dev_iter iter;
1136 if (!sif || !sif->subsys)
1139 subsys = bus_get(sif->subsys);
1143 mutex_lock(&subsys->p->mutex);
1144 list_add_tail(&sif->node, &subsys->p->interfaces);
1146 subsys_dev_iter_init(&iter, subsys, NULL, NULL);
1147 while ((dev = subsys_dev_iter_next(&iter)))
1148 sif->add_dev(dev, sif);
1149 subsys_dev_iter_exit(&iter);
1151 mutex_unlock(&subsys->p->mutex);
1155 EXPORT_SYMBOL_GPL(subsys_interface_register);
1157 void subsys_interface_unregister(struct subsys_interface *sif)
1159 struct bus_type *subsys;
1160 struct subsys_dev_iter iter;
1163 if (!sif || !sif->subsys)
1166 subsys = sif->subsys;
1168 mutex_lock(&subsys->p->mutex);
1169 list_del_init(&sif->node);
1170 if (sif->remove_dev) {
1171 subsys_dev_iter_init(&iter, subsys, NULL, NULL);
1172 while ((dev = subsys_dev_iter_next(&iter)))
1173 sif->remove_dev(dev, sif);
1174 subsys_dev_iter_exit(&iter);
1176 mutex_unlock(&subsys->p->mutex);
1180 EXPORT_SYMBOL_GPL(subsys_interface_unregister);
1182 static void system_root_device_release(struct device *dev)
1187 static int subsys_register(struct bus_type *subsys,
1188 const struct attribute_group **groups,
1189 struct kobject *parent_of_root)
1194 err = bus_register(subsys);
1198 dev = kzalloc(sizeof(struct device), GFP_KERNEL);
1204 err = dev_set_name(dev, "%s", subsys->name);
1208 dev->kobj.parent = parent_of_root;
1209 dev->groups = groups;
1210 dev->release = system_root_device_release;
1212 err = device_register(dev);
1216 subsys->dev_root = dev;
1225 bus_unregister(subsys);
1230 * subsys_system_register - register a subsystem at /sys/devices/system/
1231 * @subsys: system subsystem
1232 * @groups: default attributes for the root device
1234 * All 'system' subsystems have a /sys/devices/system/<name> root device
1235 * with the name of the subsystem. The root device can carry subsystem-
1236 * wide attributes. All registered devices are below this single root
1237 * device and are named after the subsystem with a simple enumeration
1238 * number appended. The registered devices are not explicitly named;
1239 * only 'id' in the device needs to be set.
1241 * Do not use this interface for anything new, it exists for compatibility
1242 * with bad ideas only. New subsystems should use plain subsystems; and
1243 * add the subsystem-wide attributes should be added to the subsystem
1244 * directory itself and not some create fake root-device placed in
1245 * /sys/devices/system/<name>.
1247 int subsys_system_register(struct bus_type *subsys,
1248 const struct attribute_group **groups)
1250 return subsys_register(subsys, groups, &system_kset->kobj);
1252 EXPORT_SYMBOL_GPL(subsys_system_register);
1255 * subsys_virtual_register - register a subsystem at /sys/devices/virtual/
1256 * @subsys: virtual subsystem
1257 * @groups: default attributes for the root device
1259 * All 'virtual' subsystems have a /sys/devices/system/<name> root device
1260 * with the name of the subystem. The root device can carry subsystem-wide
1261 * attributes. All registered devices are below this single root device.
1262 * There's no restriction on device naming. This is for kernel software
1263 * constructs which need sysfs interface.
1265 int subsys_virtual_register(struct bus_type *subsys,
1266 const struct attribute_group **groups)
1268 struct kobject *virtual_dir;
1270 virtual_dir = virtual_device_parent(NULL);
1274 return subsys_register(subsys, groups, virtual_dir);
1276 EXPORT_SYMBOL_GPL(subsys_virtual_register);
1278 int __init buses_init(void)
1280 bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);
1284 system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj);