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
driver_unbind(struct device_driver
*drv
,
169 const char *buf
, size_t count
)
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(unbind
, S_IWUSR
, NULL
, driver_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
driver_bind(struct device_driver
*drv
,
196 const char *buf
, size_t count
)
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(bind
, S_IWUSR
, NULL
, driver_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; attr_name(bus
->dev_attrs
[i
]); 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; attr_name(bus
->dev_attrs
[i
]); 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
= sysfs_create_link(&bus
->p
->devices_kset
->kobj
,
503 &dev
->kobj
, dev_name(dev
));
506 error
= sysfs_create_link(&dev
->kobj
,
507 &dev
->bus
->p
->subsys
.kobj
, "subsystem");
510 klist_add_tail(&dev
->p
->knode_bus
, &bus
->p
->klist_devices
);
515 sysfs_remove_link(&bus
->p
->devices_kset
->kobj
, dev_name(dev
));
517 device_remove_attrs(bus
, dev
);
524 * bus_probe_device - probe drivers for a new device
525 * @dev: device to probe
527 * - Automatically probe for a driver if the bus allows it.
529 void bus_probe_device(struct device
*dev
)
531 struct bus_type
*bus
= dev
->bus
;
532 struct subsys_interface
*sif
;
538 if (bus
->p
->drivers_autoprobe
) {
539 ret
= device_attach(dev
);
543 mutex_lock(&bus
->p
->mutex
);
544 list_for_each_entry(sif
, &bus
->p
->interfaces
, node
)
546 sif
->add_dev(dev
, sif
);
547 mutex_unlock(&bus
->p
->mutex
);
551 * bus_remove_device - remove device from bus
552 * @dev: device to be removed
554 * - Remove device from all interfaces.
555 * - Remove symlink from bus' directory.
556 * - Delete device from bus's list.
557 * - Detach from its driver.
558 * - Drop reference taken in bus_add_device().
560 void bus_remove_device(struct device
*dev
)
562 struct bus_type
*bus
= dev
->bus
;
563 struct subsys_interface
*sif
;
568 mutex_lock(&bus
->p
->mutex
);
569 list_for_each_entry(sif
, &bus
->p
->interfaces
, node
)
571 sif
->remove_dev(dev
, sif
);
572 mutex_unlock(&bus
->p
->mutex
);
574 sysfs_remove_link(&dev
->kobj
, "subsystem");
575 sysfs_remove_link(&dev
->bus
->p
->devices_kset
->kobj
,
577 device_remove_attrs(dev
->bus
, dev
);
578 if (klist_node_attached(&dev
->p
->knode_bus
))
579 klist_del(&dev
->p
->knode_bus
);
581 pr_debug("bus: '%s': remove device %s\n",
582 dev
->bus
->name
, dev_name(dev
));
583 device_release_driver(dev
);
587 static int driver_add_attrs(struct bus_type
*bus
, struct device_driver
*drv
)
592 if (bus
->drv_attrs
) {
593 for (i
= 0; attr_name(bus
->drv_attrs
[i
]); i
++) {
594 error
= driver_create_file(drv
, &bus
->drv_attrs
[i
]);
603 driver_remove_file(drv
, &bus
->drv_attrs
[i
]);
607 static void driver_remove_attrs(struct bus_type
*bus
,
608 struct device_driver
*drv
)
612 if (bus
->drv_attrs
) {
613 for (i
= 0; attr_name(bus
->drv_attrs
[i
]); i
++)
614 driver_remove_file(drv
, &bus
->drv_attrs
[i
]);
618 static int __must_check
add_bind_files(struct device_driver
*drv
)
622 ret
= driver_create_file(drv
, &driver_attr_unbind
);
624 ret
= driver_create_file(drv
, &driver_attr_bind
);
626 driver_remove_file(drv
, &driver_attr_unbind
);
631 static void remove_bind_files(struct device_driver
*drv
)
633 driver_remove_file(drv
, &driver_attr_bind
);
634 driver_remove_file(drv
, &driver_attr_unbind
);
637 static BUS_ATTR(drivers_probe
, S_IWUSR
, NULL
, store_drivers_probe
);
638 static BUS_ATTR(drivers_autoprobe
, S_IWUSR
| S_IRUGO
,
639 show_drivers_autoprobe
, store_drivers_autoprobe
);
641 static int add_probe_files(struct bus_type
*bus
)
645 retval
= bus_create_file(bus
, &bus_attr_drivers_probe
);
649 retval
= bus_create_file(bus
, &bus_attr_drivers_autoprobe
);
651 bus_remove_file(bus
, &bus_attr_drivers_probe
);
656 static void remove_probe_files(struct bus_type
*bus
)
658 bus_remove_file(bus
, &bus_attr_drivers_autoprobe
);
659 bus_remove_file(bus
, &bus_attr_drivers_probe
);
662 static ssize_t
driver_uevent_store(struct device_driver
*drv
,
663 const char *buf
, size_t count
)
665 enum kobject_action action
;
667 if (kobject_action_type(buf
, count
, &action
) == 0)
668 kobject_uevent(&drv
->p
->kobj
, action
);
671 static DRIVER_ATTR(uevent
, S_IWUSR
, NULL
, driver_uevent_store
);
674 * bus_add_driver - Add a driver to the bus.
677 int bus_add_driver(struct device_driver
*drv
)
679 struct bus_type
*bus
;
680 struct driver_private
*priv
;
683 bus
= bus_get(drv
->bus
);
687 pr_debug("bus: '%s': add driver %s\n", bus
->name
, drv
->name
);
689 priv
= kzalloc(sizeof(*priv
), GFP_KERNEL
);
694 klist_init(&priv
->klist_devices
, NULL
, NULL
);
697 priv
->kobj
.kset
= bus
->p
->drivers_kset
;
698 error
= kobject_init_and_add(&priv
->kobj
, &driver_ktype
, NULL
,
703 if (drv
->bus
->p
->drivers_autoprobe
) {
704 error
= driver_attach(drv
);
708 klist_add_tail(&priv
->knode_bus
, &bus
->p
->klist_drivers
);
709 module_add_driver(drv
->owner
, drv
);
711 error
= driver_create_file(drv
, &driver_attr_uevent
);
713 printk(KERN_ERR
"%s: uevent attr (%s) failed\n",
714 __func__
, drv
->name
);
716 error
= driver_add_attrs(bus
, drv
);
718 /* How the hell do we get out of this pickle? Give up */
719 printk(KERN_ERR
"%s: driver_add_attrs(%s) failed\n",
720 __func__
, drv
->name
);
723 if (!drv
->suppress_bind_attrs
) {
724 error
= add_bind_files(drv
);
727 printk(KERN_ERR
"%s: add_bind_files(%s) failed\n",
728 __func__
, drv
->name
);
735 kobject_put(&priv
->kobj
);
744 * bus_remove_driver - delete driver from bus's knowledge.
747 * Detach the driver from the devices it controls, and remove
748 * it from its bus's list of drivers. Finally, we drop the reference
749 * to the bus we took in bus_add_driver().
751 void bus_remove_driver(struct device_driver
*drv
)
756 if (!drv
->suppress_bind_attrs
)
757 remove_bind_files(drv
);
758 driver_remove_attrs(drv
->bus
, drv
);
759 driver_remove_file(drv
, &driver_attr_uevent
);
760 klist_remove(&drv
->p
->knode_bus
);
761 pr_debug("bus: '%s': remove driver %s\n", drv
->bus
->name
, drv
->name
);
763 module_remove_driver(drv
);
764 kobject_put(&drv
->p
->kobj
);
768 /* Helper for bus_rescan_devices's iter */
769 static int __must_check
bus_rescan_devices_helper(struct device
*dev
,
775 if (dev
->parent
) /* Needed for USB */
776 device_lock(dev
->parent
);
777 ret
= device_attach(dev
);
779 device_unlock(dev
->parent
);
781 return ret
< 0 ? ret
: 0;
785 * bus_rescan_devices - rescan devices on the bus for possible drivers
786 * @bus: the bus to scan.
788 * This function will look for devices on the bus with no driver
789 * attached and rescan it against existing drivers to see if it matches
790 * any by calling device_attach() for the unbound devices.
792 int bus_rescan_devices(struct bus_type
*bus
)
794 return bus_for_each_dev(bus
, NULL
, NULL
, bus_rescan_devices_helper
);
796 EXPORT_SYMBOL_GPL(bus_rescan_devices
);
799 * device_reprobe - remove driver for a device and probe for a new driver
800 * @dev: the device to reprobe
802 * This function detaches the attached driver (if any) for the given
803 * device and restarts the driver probing process. It is intended
804 * to use if probing criteria changed during a devices lifetime and
805 * driver attachment should change accordingly.
807 int device_reprobe(struct device
*dev
)
810 if (dev
->parent
) /* Needed for USB */
811 device_lock(dev
->parent
);
812 device_release_driver(dev
);
814 device_unlock(dev
->parent
);
816 return bus_rescan_devices_helper(dev
, NULL
);
818 EXPORT_SYMBOL_GPL(device_reprobe
);
821 * find_bus - locate bus by name.
822 * @name: name of bus.
824 * Call kset_find_obj() to iterate over list of buses to
825 * find a bus by name. Return bus if found.
827 * Note that kset_find_obj increments bus' reference count.
830 struct bus_type
*find_bus(char *name
)
832 struct kobject
*k
= kset_find_obj(bus_kset
, name
);
833 return k
? to_bus(k
) : NULL
;
839 * bus_add_attrs - Add default attributes for this bus.
840 * @bus: Bus that has just been registered.
843 static int bus_add_attrs(struct bus_type
*bus
)
848 if (bus
->bus_attrs
) {
849 for (i
= 0; attr_name(bus
->bus_attrs
[i
]); i
++) {
850 error
= bus_create_file(bus
, &bus
->bus_attrs
[i
]);
859 bus_remove_file(bus
, &bus
->bus_attrs
[i
]);
863 static void bus_remove_attrs(struct bus_type
*bus
)
867 if (bus
->bus_attrs
) {
868 for (i
= 0; attr_name(bus
->bus_attrs
[i
]); i
++)
869 bus_remove_file(bus
, &bus
->bus_attrs
[i
]);
873 static void klist_devices_get(struct klist_node
*n
)
875 struct device_private
*dev_prv
= to_device_private_bus(n
);
876 struct device
*dev
= dev_prv
->device
;
881 static void klist_devices_put(struct klist_node
*n
)
883 struct device_private
*dev_prv
= to_device_private_bus(n
);
884 struct device
*dev
= dev_prv
->device
;
889 static ssize_t
bus_uevent_store(struct bus_type
*bus
,
890 const char *buf
, size_t count
)
892 enum kobject_action action
;
894 if (kobject_action_type(buf
, count
, &action
) == 0)
895 kobject_uevent(&bus
->p
->subsys
.kobj
, action
);
898 static BUS_ATTR(uevent
, S_IWUSR
, NULL
, bus_uevent_store
);
901 * __bus_register - register a driver-core subsystem
902 * @bus: bus to register
903 * @key: lockdep class key
905 * Once we have that, we register the bus with the kobject
906 * infrastructure, then register the children subsystems it has:
907 * the devices and drivers that belong to the subsystem.
909 int __bus_register(struct bus_type
*bus
, struct lock_class_key
*key
)
912 struct subsys_private
*priv
;
914 priv
= kzalloc(sizeof(struct subsys_private
), GFP_KERNEL
);
921 BLOCKING_INIT_NOTIFIER_HEAD(&priv
->bus_notifier
);
923 retval
= kobject_set_name(&priv
->subsys
.kobj
, "%s", bus
->name
);
927 priv
->subsys
.kobj
.kset
= bus_kset
;
928 priv
->subsys
.kobj
.ktype
= &bus_ktype
;
929 priv
->drivers_autoprobe
= 1;
931 retval
= kset_register(&priv
->subsys
);
935 retval
= bus_create_file(bus
, &bus_attr_uevent
);
937 goto bus_uevent_fail
;
939 priv
->devices_kset
= kset_create_and_add("devices", NULL
,
941 if (!priv
->devices_kset
) {
943 goto bus_devices_fail
;
946 priv
->drivers_kset
= kset_create_and_add("drivers", NULL
,
948 if (!priv
->drivers_kset
) {
950 goto bus_drivers_fail
;
953 INIT_LIST_HEAD(&priv
->interfaces
);
954 __mutex_init(&priv
->mutex
, "subsys mutex", key
);
955 klist_init(&priv
->klist_devices
, klist_devices_get
, klist_devices_put
);
956 klist_init(&priv
->klist_drivers
, NULL
, NULL
);
958 retval
= add_probe_files(bus
);
960 goto bus_probe_files_fail
;
962 retval
= bus_add_attrs(bus
);
966 pr_debug("bus: '%s': registered\n", bus
->name
);
970 remove_probe_files(bus
);
971 bus_probe_files_fail
:
972 kset_unregister(bus
->p
->drivers_kset
);
974 kset_unregister(bus
->p
->devices_kset
);
976 bus_remove_file(bus
, &bus_attr_uevent
);
978 kset_unregister(&bus
->p
->subsys
);
984 EXPORT_SYMBOL_GPL(__bus_register
);
987 * bus_unregister - remove a bus from the system
990 * Unregister the child subsystems and the bus itself.
991 * Finally, we call bus_put() to release the refcount
993 void bus_unregister(struct bus_type
*bus
)
995 pr_debug("bus: '%s': unregistering\n", bus
->name
);
997 device_unregister(bus
->dev_root
);
998 bus_remove_attrs(bus
);
999 remove_probe_files(bus
);
1000 kset_unregister(bus
->p
->drivers_kset
);
1001 kset_unregister(bus
->p
->devices_kset
);
1002 bus_remove_file(bus
, &bus_attr_uevent
);
1003 kset_unregister(&bus
->p
->subsys
);
1007 EXPORT_SYMBOL_GPL(bus_unregister
);
1009 int bus_register_notifier(struct bus_type
*bus
, struct notifier_block
*nb
)
1011 return blocking_notifier_chain_register(&bus
->p
->bus_notifier
, nb
);
1013 EXPORT_SYMBOL_GPL(bus_register_notifier
);
1015 int bus_unregister_notifier(struct bus_type
*bus
, struct notifier_block
*nb
)
1017 return blocking_notifier_chain_unregister(&bus
->p
->bus_notifier
, nb
);
1019 EXPORT_SYMBOL_GPL(bus_unregister_notifier
);
1021 struct kset
*bus_get_kset(struct bus_type
*bus
)
1023 return &bus
->p
->subsys
;
1025 EXPORT_SYMBOL_GPL(bus_get_kset
);
1027 struct klist
*bus_get_device_klist(struct bus_type
*bus
)
1029 return &bus
->p
->klist_devices
;
1031 EXPORT_SYMBOL_GPL(bus_get_device_klist
);
1034 * Yes, this forcibly breaks the klist abstraction temporarily. It
1035 * just wants to sort the klist, not change reference counts and
1036 * take/drop locks rapidly in the process. It does all this while
1037 * holding the lock for the list, so objects can't otherwise be
1038 * added/removed while we're swizzling.
1040 static void device_insertion_sort_klist(struct device
*a
, struct list_head
*list
,
1041 int (*compare
)(const struct device
*a
,
1042 const struct device
*b
))
1044 struct list_head
*pos
;
1045 struct klist_node
*n
;
1046 struct device_private
*dev_prv
;
1049 list_for_each(pos
, list
) {
1050 n
= container_of(pos
, struct klist_node
, n_node
);
1051 dev_prv
= to_device_private_bus(n
);
1052 b
= dev_prv
->device
;
1053 if (compare(a
, b
) <= 0) {
1054 list_move_tail(&a
->p
->knode_bus
.n_node
,
1055 &b
->p
->knode_bus
.n_node
);
1059 list_move_tail(&a
->p
->knode_bus
.n_node
, list
);
1062 void bus_sort_breadthfirst(struct bus_type
*bus
,
1063 int (*compare
)(const struct device
*a
,
1064 const struct device
*b
))
1066 LIST_HEAD(sorted_devices
);
1067 struct list_head
*pos
, *tmp
;
1068 struct klist_node
*n
;
1069 struct device_private
*dev_prv
;
1071 struct klist
*device_klist
;
1073 device_klist
= bus_get_device_klist(bus
);
1075 spin_lock(&device_klist
->k_lock
);
1076 list_for_each_safe(pos
, tmp
, &device_klist
->k_list
) {
1077 n
= container_of(pos
, struct klist_node
, n_node
);
1078 dev_prv
= to_device_private_bus(n
);
1079 dev
= dev_prv
->device
;
1080 device_insertion_sort_klist(dev
, &sorted_devices
, compare
);
1082 list_splice(&sorted_devices
, &device_klist
->k_list
);
1083 spin_unlock(&device_klist
->k_lock
);
1085 EXPORT_SYMBOL_GPL(bus_sort_breadthfirst
);
1088 * subsys_dev_iter_init - initialize subsys device iterator
1089 * @iter: subsys iterator to initialize
1090 * @subsys: the subsys we wanna iterate over
1091 * @start: the device to start iterating from, if any
1092 * @type: device_type of the devices to iterate over, NULL for all
1094 * Initialize subsys iterator @iter such that it iterates over devices
1095 * of @subsys. If @start is set, the list iteration will start there,
1096 * otherwise if it is NULL, the iteration starts at the beginning of
1099 void subsys_dev_iter_init(struct subsys_dev_iter
*iter
, struct bus_type
*subsys
,
1100 struct device
*start
, const struct device_type
*type
)
1102 struct klist_node
*start_knode
= NULL
;
1105 start_knode
= &start
->p
->knode_bus
;
1106 klist_iter_init_node(&subsys
->p
->klist_devices
, &iter
->ki
, start_knode
);
1109 EXPORT_SYMBOL_GPL(subsys_dev_iter_init
);
1112 * subsys_dev_iter_next - iterate to the next device
1113 * @iter: subsys iterator to proceed
1115 * Proceed @iter to the next device and return it. Returns NULL if
1116 * iteration is complete.
1118 * The returned device is referenced and won't be released till
1119 * iterator is proceed to the next device or exited. The caller is
1120 * free to do whatever it wants to do with the device including
1121 * calling back into subsys code.
1123 struct device
*subsys_dev_iter_next(struct subsys_dev_iter
*iter
)
1125 struct klist_node
*knode
;
1129 knode
= klist_next(&iter
->ki
);
1132 dev
= container_of(knode
, struct device_private
, knode_bus
)->device
;
1133 if (!iter
->type
|| iter
->type
== dev
->type
)
1137 EXPORT_SYMBOL_GPL(subsys_dev_iter_next
);
1140 * subsys_dev_iter_exit - finish iteration
1141 * @iter: subsys iterator to finish
1143 * Finish an iteration. Always call this function after iteration is
1144 * complete whether the iteration ran till the end or not.
1146 void subsys_dev_iter_exit(struct subsys_dev_iter
*iter
)
1148 klist_iter_exit(&iter
->ki
);
1150 EXPORT_SYMBOL_GPL(subsys_dev_iter_exit
);
1152 int subsys_interface_register(struct subsys_interface
*sif
)
1154 struct bus_type
*subsys
;
1155 struct subsys_dev_iter iter
;
1158 if (!sif
|| !sif
->subsys
)
1161 subsys
= bus_get(sif
->subsys
);
1165 mutex_lock(&subsys
->p
->mutex
);
1166 list_add_tail(&sif
->node
, &subsys
->p
->interfaces
);
1168 subsys_dev_iter_init(&iter
, subsys
, NULL
, NULL
);
1169 while ((dev
= subsys_dev_iter_next(&iter
)))
1170 sif
->add_dev(dev
, sif
);
1171 subsys_dev_iter_exit(&iter
);
1173 mutex_unlock(&subsys
->p
->mutex
);
1177 EXPORT_SYMBOL_GPL(subsys_interface_register
);
1179 void subsys_interface_unregister(struct subsys_interface
*sif
)
1181 struct bus_type
*subsys
;
1182 struct subsys_dev_iter iter
;
1185 if (!sif
|| !sif
->subsys
)
1188 subsys
= sif
->subsys
;
1190 mutex_lock(&subsys
->p
->mutex
);
1191 list_del_init(&sif
->node
);
1192 if (sif
->remove_dev
) {
1193 subsys_dev_iter_init(&iter
, subsys
, NULL
, NULL
);
1194 while ((dev
= subsys_dev_iter_next(&iter
)))
1195 sif
->remove_dev(dev
, sif
);
1196 subsys_dev_iter_exit(&iter
);
1198 mutex_unlock(&subsys
->p
->mutex
);
1202 EXPORT_SYMBOL_GPL(subsys_interface_unregister
);
1204 static void system_root_device_release(struct device
*dev
)
1209 * subsys_system_register - register a subsystem at /sys/devices/system/
1210 * @subsys: system subsystem
1211 * @groups: default attributes for the root device
1213 * All 'system' subsystems have a /sys/devices/system/<name> root device
1214 * with the name of the subsystem. The root device can carry subsystem-
1215 * wide attributes. All registered devices are below this single root
1216 * device and are named after the subsystem with a simple enumeration
1217 * number appended. The registered devices are not explicitely named;
1218 * only 'id' in the device needs to be set.
1220 * Do not use this interface for anything new, it exists for compatibility
1221 * with bad ideas only. New subsystems should use plain subsystems; and
1222 * add the subsystem-wide attributes should be added to the subsystem
1223 * directory itself and not some create fake root-device placed in
1224 * /sys/devices/system/<name>.
1226 int subsys_system_register(struct bus_type
*subsys
,
1227 const struct attribute_group
**groups
)
1232 err
= bus_register(subsys
);
1236 dev
= kzalloc(sizeof(struct device
), GFP_KERNEL
);
1242 err
= dev_set_name(dev
, "%s", subsys
->name
);
1246 dev
->kobj
.parent
= &system_kset
->kobj
;
1247 dev
->groups
= groups
;
1248 dev
->release
= system_root_device_release
;
1250 err
= device_register(dev
);
1254 subsys
->dev_root
= dev
;
1263 bus_unregister(subsys
);
1266 EXPORT_SYMBOL_GPL(subsys_system_register
);
1268 int __init
buses_init(void)
1270 bus_kset
= kset_create_and_add("bus", &bus_uevent_ops
, NULL
);
1274 system_kset
= kset_create_and_add("system", NULL
, &devices_kset
->kobj
);