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
)
247 dev
= bus_find_device_by_name(bus
, NULL
, buf
);
250 if (bus_rescan_devices_helper(dev
, NULL
) == 0)
256 static struct device
*next_device(struct klist_iter
*i
)
258 struct klist_node
*n
= klist_next(i
);
259 struct device
*dev
= NULL
;
260 struct device_private
*dev_prv
;
263 dev_prv
= to_device_private_bus(n
);
264 dev
= dev_prv
->device
;
270 * bus_for_each_dev - device iterator.
272 * @start: device to start iterating from.
273 * @data: data for the callback.
274 * @fn: function to be called for each device.
276 * Iterate over @bus's list of devices, and call @fn for each,
277 * passing it @data. If @start is not NULL, we use that device to
278 * begin iterating from.
280 * We check the return of @fn each time. If it returns anything
281 * other than 0, we break out and return that value.
283 * NOTE: The device that returns a non-zero value is not retained
284 * in any way, nor is its refcount incremented. If the caller needs
285 * to retain this data, it should do so, and increment the reference
286 * count in the supplied callback.
288 int bus_for_each_dev(struct bus_type
*bus
, struct device
*start
,
289 void *data
, int (*fn
)(struct device
*, void *))
298 klist_iter_init_node(&bus
->p
->klist_devices
, &i
,
299 (start
? &start
->p
->knode_bus
: NULL
));
300 while ((dev
= next_device(&i
)) && !error
)
301 error
= fn(dev
, data
);
305 EXPORT_SYMBOL_GPL(bus_for_each_dev
);
308 * bus_find_device - device iterator for locating a particular device.
310 * @start: Device to begin with
311 * @data: Data to pass to match function
312 * @match: Callback function to check device
314 * This is similar to the bus_for_each_dev() function above, but it
315 * returns a reference to a device that is 'found' for later use, as
316 * determined by the @match callback.
318 * The callback should return 0 if the device doesn't match and non-zero
319 * if it does. If the callback returns non-zero, this function will
320 * return to the caller and not iterate over any more devices.
322 struct device
*bus_find_device(struct bus_type
*bus
,
323 struct device
*start
, void *data
,
324 int (*match
)(struct device
*dev
, void *data
))
332 klist_iter_init_node(&bus
->p
->klist_devices
, &i
,
333 (start
? &start
->p
->knode_bus
: NULL
));
334 while ((dev
= next_device(&i
)))
335 if (match(dev
, data
) && get_device(dev
))
340 EXPORT_SYMBOL_GPL(bus_find_device
);
342 static int match_name(struct device
*dev
, void *data
)
344 const char *name
= data
;
346 return sysfs_streq(name
, dev_name(dev
));
350 * bus_find_device_by_name - device iterator for locating a particular device of a specific name
352 * @start: Device to begin with
353 * @name: name of the device to match
355 * This is similar to the bus_find_device() function above, but it handles
356 * searching by a name automatically, no need to write another strcmp matching
359 struct device
*bus_find_device_by_name(struct bus_type
*bus
,
360 struct device
*start
, const char *name
)
362 return bus_find_device(bus
, start
, (void *)name
, match_name
);
364 EXPORT_SYMBOL_GPL(bus_find_device_by_name
);
367 * subsys_find_device_by_id - find a device with a specific enumeration number
369 * @id: index 'id' in struct device
370 * @hint: device to check first
372 * Check the hint's next object and if it is a match return it directly,
373 * otherwise, fall back to a full list search. Either way a reference for
374 * the returned object is taken.
376 struct device
*subsys_find_device_by_id(struct bus_type
*subsys
, unsigned int id
,
386 klist_iter_init_node(&subsys
->p
->klist_devices
, &i
, &hint
->p
->knode_bus
);
387 dev
= next_device(&i
);
388 if (dev
&& dev
->id
== id
&& get_device(dev
)) {
395 klist_iter_init_node(&subsys
->p
->klist_devices
, &i
, NULL
);
396 while ((dev
= next_device(&i
))) {
397 if (dev
->id
== id
&& get_device(dev
)) {
405 EXPORT_SYMBOL_GPL(subsys_find_device_by_id
);
407 static struct device_driver
*next_driver(struct klist_iter
*i
)
409 struct klist_node
*n
= klist_next(i
);
410 struct driver_private
*drv_priv
;
413 drv_priv
= container_of(n
, struct driver_private
, knode_bus
);
414 return drv_priv
->driver
;
420 * bus_for_each_drv - driver iterator
421 * @bus: bus we're dealing with.
422 * @start: driver to start iterating on.
423 * @data: data to pass to the callback.
424 * @fn: function to call for each driver.
426 * This is nearly identical to the device iterator above.
427 * We iterate over each driver that belongs to @bus, and call
428 * @fn for each. If @fn returns anything but 0, we break out
429 * and return it. If @start is not NULL, we use it as the head
432 * NOTE: we don't return the driver that returns a non-zero
433 * value, nor do we leave the reference count incremented for that
434 * driver. If the caller needs to know that info, it must set it
435 * in the callback. It must also be sure to increment the refcount
436 * so it doesn't disappear before returning to the caller.
438 int bus_for_each_drv(struct bus_type
*bus
, struct device_driver
*start
,
439 void *data
, int (*fn
)(struct device_driver
*, void *))
442 struct device_driver
*drv
;
448 klist_iter_init_node(&bus
->p
->klist_drivers
, &i
,
449 start
? &start
->p
->knode_bus
: NULL
);
450 while ((drv
= next_driver(&i
)) && !error
)
451 error
= fn(drv
, data
);
455 EXPORT_SYMBOL_GPL(bus_for_each_drv
);
457 static int device_add_attrs(struct bus_type
*bus
, struct device
*dev
)
465 for (i
= 0; attr_name(bus
->dev_attrs
[i
]); i
++) {
466 error
= device_create_file(dev
, &bus
->dev_attrs
[i
]);
469 device_remove_file(dev
, &bus
->dev_attrs
[i
]);
476 static void device_remove_attrs(struct bus_type
*bus
, struct device
*dev
)
480 if (bus
->dev_attrs
) {
481 for (i
= 0; attr_name(bus
->dev_attrs
[i
]); i
++)
482 device_remove_file(dev
, &bus
->dev_attrs
[i
]);
487 * bus_add_device - add device to bus
488 * @dev: device being added
490 * - Add device's bus attributes.
491 * - Create links to device's bus.
492 * - Add the device to its bus's list of devices.
494 int bus_add_device(struct device
*dev
)
496 struct bus_type
*bus
= bus_get(dev
->bus
);
500 pr_debug("bus: '%s': add device %s\n", bus
->name
, dev_name(dev
));
501 error
= device_add_attrs(bus
, dev
);
504 error
= sysfs_create_link(&bus
->p
->devices_kset
->kobj
,
505 &dev
->kobj
, dev_name(dev
));
508 error
= sysfs_create_link(&dev
->kobj
,
509 &dev
->bus
->p
->subsys
.kobj
, "subsystem");
512 klist_add_tail(&dev
->p
->knode_bus
, &bus
->p
->klist_devices
);
517 sysfs_remove_link(&bus
->p
->devices_kset
->kobj
, dev_name(dev
));
519 device_remove_attrs(bus
, dev
);
526 * bus_probe_device - probe drivers for a new device
527 * @dev: device to probe
529 * - Automatically probe for a driver if the bus allows it.
531 void bus_probe_device(struct device
*dev
)
533 struct bus_type
*bus
= dev
->bus
;
534 struct subsys_interface
*sif
;
540 if (bus
->p
->drivers_autoprobe
) {
541 ret
= device_attach(dev
);
545 mutex_lock(&bus
->p
->mutex
);
546 list_for_each_entry(sif
, &bus
->p
->interfaces
, node
)
548 sif
->add_dev(dev
, sif
);
549 mutex_unlock(&bus
->p
->mutex
);
553 * bus_remove_device - remove device from bus
554 * @dev: device to be removed
556 * - Remove device from all interfaces.
557 * - Remove symlink from bus' directory.
558 * - Delete device from bus's list.
559 * - Detach from its driver.
560 * - Drop reference taken in bus_add_device().
562 void bus_remove_device(struct device
*dev
)
564 struct bus_type
*bus
= dev
->bus
;
565 struct subsys_interface
*sif
;
570 mutex_lock(&bus
->p
->mutex
);
571 list_for_each_entry(sif
, &bus
->p
->interfaces
, node
)
573 sif
->remove_dev(dev
, sif
);
574 mutex_unlock(&bus
->p
->mutex
);
576 sysfs_remove_link(&dev
->kobj
, "subsystem");
577 sysfs_remove_link(&dev
->bus
->p
->devices_kset
->kobj
,
579 device_remove_attrs(dev
->bus
, dev
);
580 if (klist_node_attached(&dev
->p
->knode_bus
))
581 klist_del(&dev
->p
->knode_bus
);
583 pr_debug("bus: '%s': remove device %s\n",
584 dev
->bus
->name
, dev_name(dev
));
585 device_release_driver(dev
);
589 static int driver_add_attrs(struct bus_type
*bus
, struct device_driver
*drv
)
594 if (bus
->drv_attrs
) {
595 for (i
= 0; attr_name(bus
->drv_attrs
[i
]); i
++) {
596 error
= driver_create_file(drv
, &bus
->drv_attrs
[i
]);
605 driver_remove_file(drv
, &bus
->drv_attrs
[i
]);
609 static void driver_remove_attrs(struct bus_type
*bus
,
610 struct device_driver
*drv
)
614 if (bus
->drv_attrs
) {
615 for (i
= 0; attr_name(bus
->drv_attrs
[i
]); i
++)
616 driver_remove_file(drv
, &bus
->drv_attrs
[i
]);
620 static int __must_check
add_bind_files(struct device_driver
*drv
)
624 ret
= driver_create_file(drv
, &driver_attr_unbind
);
626 ret
= driver_create_file(drv
, &driver_attr_bind
);
628 driver_remove_file(drv
, &driver_attr_unbind
);
633 static void remove_bind_files(struct device_driver
*drv
)
635 driver_remove_file(drv
, &driver_attr_bind
);
636 driver_remove_file(drv
, &driver_attr_unbind
);
639 static BUS_ATTR(drivers_probe
, S_IWUSR
, NULL
, store_drivers_probe
);
640 static BUS_ATTR(drivers_autoprobe
, S_IWUSR
| S_IRUGO
,
641 show_drivers_autoprobe
, store_drivers_autoprobe
);
643 static int add_probe_files(struct bus_type
*bus
)
647 retval
= bus_create_file(bus
, &bus_attr_drivers_probe
);
651 retval
= bus_create_file(bus
, &bus_attr_drivers_autoprobe
);
653 bus_remove_file(bus
, &bus_attr_drivers_probe
);
658 static void remove_probe_files(struct bus_type
*bus
)
660 bus_remove_file(bus
, &bus_attr_drivers_autoprobe
);
661 bus_remove_file(bus
, &bus_attr_drivers_probe
);
664 static ssize_t
driver_uevent_store(struct device_driver
*drv
,
665 const char *buf
, size_t count
)
667 enum kobject_action action
;
669 if (kobject_action_type(buf
, count
, &action
) == 0)
670 kobject_uevent(&drv
->p
->kobj
, action
);
673 static DRIVER_ATTR(uevent
, S_IWUSR
, NULL
, driver_uevent_store
);
676 * bus_add_driver - Add a driver to the bus.
679 int bus_add_driver(struct device_driver
*drv
)
681 struct bus_type
*bus
;
682 struct driver_private
*priv
;
685 bus
= bus_get(drv
->bus
);
689 pr_debug("bus: '%s': add driver %s\n", bus
->name
, drv
->name
);
691 priv
= kzalloc(sizeof(*priv
), GFP_KERNEL
);
696 klist_init(&priv
->klist_devices
, NULL
, NULL
);
699 priv
->kobj
.kset
= bus
->p
->drivers_kset
;
700 error
= kobject_init_and_add(&priv
->kobj
, &driver_ktype
, NULL
,
705 klist_add_tail(&priv
->knode_bus
, &bus
->p
->klist_drivers
);
706 if (drv
->bus
->p
->drivers_autoprobe
) {
707 error
= driver_attach(drv
);
711 module_add_driver(drv
->owner
, drv
);
713 error
= driver_create_file(drv
, &driver_attr_uevent
);
715 printk(KERN_ERR
"%s: uevent attr (%s) failed\n",
716 __func__
, drv
->name
);
718 error
= driver_add_attrs(bus
, drv
);
720 /* How the hell do we get out of this pickle? Give up */
721 printk(KERN_ERR
"%s: driver_add_attrs(%s) failed\n",
722 __func__
, drv
->name
);
725 if (!drv
->suppress_bind_attrs
) {
726 error
= add_bind_files(drv
);
729 printk(KERN_ERR
"%s: add_bind_files(%s) failed\n",
730 __func__
, drv
->name
);
737 kobject_put(&priv
->kobj
);
746 * bus_remove_driver - delete driver from bus's knowledge.
749 * Detach the driver from the devices it controls, and remove
750 * it from its bus's list of drivers. Finally, we drop the reference
751 * to the bus we took in bus_add_driver().
753 void bus_remove_driver(struct device_driver
*drv
)
758 if (!drv
->suppress_bind_attrs
)
759 remove_bind_files(drv
);
760 driver_remove_attrs(drv
->bus
, drv
);
761 driver_remove_file(drv
, &driver_attr_uevent
);
762 klist_remove(&drv
->p
->knode_bus
);
763 pr_debug("bus: '%s': remove driver %s\n", drv
->bus
->name
, drv
->name
);
765 module_remove_driver(drv
);
766 kobject_put(&drv
->p
->kobj
);
770 /* Helper for bus_rescan_devices's iter */
771 static int __must_check
bus_rescan_devices_helper(struct device
*dev
,
777 if (dev
->parent
) /* Needed for USB */
778 device_lock(dev
->parent
);
779 ret
= device_attach(dev
);
781 device_unlock(dev
->parent
);
783 return ret
< 0 ? ret
: 0;
787 * bus_rescan_devices - rescan devices on the bus for possible drivers
788 * @bus: the bus to scan.
790 * This function will look for devices on the bus with no driver
791 * attached and rescan it against existing drivers to see if it matches
792 * any by calling device_attach() for the unbound devices.
794 int bus_rescan_devices(struct bus_type
*bus
)
796 return bus_for_each_dev(bus
, NULL
, NULL
, bus_rescan_devices_helper
);
798 EXPORT_SYMBOL_GPL(bus_rescan_devices
);
801 * device_reprobe - remove driver for a device and probe for a new driver
802 * @dev: the device to reprobe
804 * This function detaches the attached driver (if any) for the given
805 * device and restarts the driver probing process. It is intended
806 * to use if probing criteria changed during a devices lifetime and
807 * driver attachment should change accordingly.
809 int device_reprobe(struct device
*dev
)
812 if (dev
->parent
) /* Needed for USB */
813 device_lock(dev
->parent
);
814 device_release_driver(dev
);
816 device_unlock(dev
->parent
);
818 return bus_rescan_devices_helper(dev
, NULL
);
820 EXPORT_SYMBOL_GPL(device_reprobe
);
823 * find_bus - locate bus by name.
824 * @name: name of bus.
826 * Call kset_find_obj() to iterate over list of buses to
827 * find a bus by name. Return bus if found.
829 * Note that kset_find_obj increments bus' reference count.
832 struct bus_type
*find_bus(char *name
)
834 struct kobject
*k
= kset_find_obj(bus_kset
, name
);
835 return k
? to_bus(k
) : NULL
;
841 * bus_add_attrs - Add default attributes for this bus.
842 * @bus: Bus that has just been registered.
845 static int bus_add_attrs(struct bus_type
*bus
)
850 if (bus
->bus_attrs
) {
851 for (i
= 0; attr_name(bus
->bus_attrs
[i
]); i
++) {
852 error
= bus_create_file(bus
, &bus
->bus_attrs
[i
]);
861 bus_remove_file(bus
, &bus
->bus_attrs
[i
]);
865 static void bus_remove_attrs(struct bus_type
*bus
)
869 if (bus
->bus_attrs
) {
870 for (i
= 0; attr_name(bus
->bus_attrs
[i
]); i
++)
871 bus_remove_file(bus
, &bus
->bus_attrs
[i
]);
875 static void klist_devices_get(struct klist_node
*n
)
877 struct device_private
*dev_prv
= to_device_private_bus(n
);
878 struct device
*dev
= dev_prv
->device
;
883 static void klist_devices_put(struct klist_node
*n
)
885 struct device_private
*dev_prv
= to_device_private_bus(n
);
886 struct device
*dev
= dev_prv
->device
;
891 static ssize_t
bus_uevent_store(struct bus_type
*bus
,
892 const char *buf
, size_t count
)
894 enum kobject_action action
;
896 if (kobject_action_type(buf
, count
, &action
) == 0)
897 kobject_uevent(&bus
->p
->subsys
.kobj
, action
);
900 static BUS_ATTR(uevent
, S_IWUSR
, NULL
, bus_uevent_store
);
903 * bus_register - register a driver-core subsystem
904 * @bus: bus to register
906 * Once we have that, we register the bus with the kobject
907 * infrastructure, then register the children subsystems it has:
908 * the devices and drivers that belong to the subsystem.
910 int bus_register(struct bus_type
*bus
)
913 struct subsys_private
*priv
;
914 struct lock_class_key
*key
= &bus
->lock_key
;
916 priv
= kzalloc(sizeof(struct subsys_private
), GFP_KERNEL
);
923 BLOCKING_INIT_NOTIFIER_HEAD(&priv
->bus_notifier
);
925 retval
= kobject_set_name(&priv
->subsys
.kobj
, "%s", bus
->name
);
929 priv
->subsys
.kobj
.kset
= bus_kset
;
930 priv
->subsys
.kobj
.ktype
= &bus_ktype
;
931 priv
->drivers_autoprobe
= 1;
933 retval
= kset_register(&priv
->subsys
);
937 retval
= bus_create_file(bus
, &bus_attr_uevent
);
939 goto bus_uevent_fail
;
941 priv
->devices_kset
= kset_create_and_add("devices", NULL
,
943 if (!priv
->devices_kset
) {
945 goto bus_devices_fail
;
948 priv
->drivers_kset
= kset_create_and_add("drivers", NULL
,
950 if (!priv
->drivers_kset
) {
952 goto bus_drivers_fail
;
955 INIT_LIST_HEAD(&priv
->interfaces
);
956 __mutex_init(&priv
->mutex
, "subsys mutex", key
);
957 klist_init(&priv
->klist_devices
, klist_devices_get
, klist_devices_put
);
958 klist_init(&priv
->klist_drivers
, NULL
, NULL
);
960 retval
= add_probe_files(bus
);
962 goto bus_probe_files_fail
;
964 retval
= bus_add_attrs(bus
);
968 pr_debug("bus: '%s': registered\n", bus
->name
);
972 remove_probe_files(bus
);
973 bus_probe_files_fail
:
974 kset_unregister(bus
->p
->drivers_kset
);
976 kset_unregister(bus
->p
->devices_kset
);
978 bus_remove_file(bus
, &bus_attr_uevent
);
980 kset_unregister(&bus
->p
->subsys
);
986 EXPORT_SYMBOL_GPL(bus_register
);
989 * bus_unregister - remove a bus from the system
992 * Unregister the child subsystems and the bus itself.
993 * Finally, we call bus_put() to release the refcount
995 void bus_unregister(struct bus_type
*bus
)
997 pr_debug("bus: '%s': unregistering\n", bus
->name
);
999 device_unregister(bus
->dev_root
);
1000 bus_remove_attrs(bus
);
1001 remove_probe_files(bus
);
1002 kset_unregister(bus
->p
->drivers_kset
);
1003 kset_unregister(bus
->p
->devices_kset
);
1004 bus_remove_file(bus
, &bus_attr_uevent
);
1005 kset_unregister(&bus
->p
->subsys
);
1009 EXPORT_SYMBOL_GPL(bus_unregister
);
1011 int bus_register_notifier(struct bus_type
*bus
, struct notifier_block
*nb
)
1013 return blocking_notifier_chain_register(&bus
->p
->bus_notifier
, nb
);
1015 EXPORT_SYMBOL_GPL(bus_register_notifier
);
1017 int bus_unregister_notifier(struct bus_type
*bus
, struct notifier_block
*nb
)
1019 return blocking_notifier_chain_unregister(&bus
->p
->bus_notifier
, nb
);
1021 EXPORT_SYMBOL_GPL(bus_unregister_notifier
);
1023 struct kset
*bus_get_kset(struct bus_type
*bus
)
1025 return &bus
->p
->subsys
;
1027 EXPORT_SYMBOL_GPL(bus_get_kset
);
1029 struct klist
*bus_get_device_klist(struct bus_type
*bus
)
1031 return &bus
->p
->klist_devices
;
1033 EXPORT_SYMBOL_GPL(bus_get_device_klist
);
1036 * Yes, this forcibly breaks the klist abstraction temporarily. It
1037 * just wants to sort the klist, not change reference counts and
1038 * take/drop locks rapidly in the process. It does all this while
1039 * holding the lock for the list, so objects can't otherwise be
1040 * added/removed while we're swizzling.
1042 static void device_insertion_sort_klist(struct device
*a
, struct list_head
*list
,
1043 int (*compare
)(const struct device
*a
,
1044 const struct device
*b
))
1046 struct list_head
*pos
;
1047 struct klist_node
*n
;
1048 struct device_private
*dev_prv
;
1051 list_for_each(pos
, list
) {
1052 n
= container_of(pos
, struct klist_node
, n_node
);
1053 dev_prv
= to_device_private_bus(n
);
1054 b
= dev_prv
->device
;
1055 if (compare(a
, b
) <= 0) {
1056 list_move_tail(&a
->p
->knode_bus
.n_node
,
1057 &b
->p
->knode_bus
.n_node
);
1061 list_move_tail(&a
->p
->knode_bus
.n_node
, list
);
1064 void bus_sort_breadthfirst(struct bus_type
*bus
,
1065 int (*compare
)(const struct device
*a
,
1066 const struct device
*b
))
1068 LIST_HEAD(sorted_devices
);
1069 struct list_head
*pos
, *tmp
;
1070 struct klist_node
*n
;
1071 struct device_private
*dev_prv
;
1073 struct klist
*device_klist
;
1075 device_klist
= bus_get_device_klist(bus
);
1077 spin_lock(&device_klist
->k_lock
);
1078 list_for_each_safe(pos
, tmp
, &device_klist
->k_list
) {
1079 n
= container_of(pos
, struct klist_node
, n_node
);
1080 dev_prv
= to_device_private_bus(n
);
1081 dev
= dev_prv
->device
;
1082 device_insertion_sort_klist(dev
, &sorted_devices
, compare
);
1084 list_splice(&sorted_devices
, &device_klist
->k_list
);
1085 spin_unlock(&device_klist
->k_lock
);
1087 EXPORT_SYMBOL_GPL(bus_sort_breadthfirst
);
1090 * subsys_dev_iter_init - initialize subsys device iterator
1091 * @iter: subsys iterator to initialize
1092 * @subsys: the subsys we wanna iterate over
1093 * @start: the device to start iterating from, if any
1094 * @type: device_type of the devices to iterate over, NULL for all
1096 * Initialize subsys iterator @iter such that it iterates over devices
1097 * of @subsys. If @start is set, the list iteration will start there,
1098 * otherwise if it is NULL, the iteration starts at the beginning of
1101 void subsys_dev_iter_init(struct subsys_dev_iter
*iter
, struct bus_type
*subsys
,
1102 struct device
*start
, const struct device_type
*type
)
1104 struct klist_node
*start_knode
= NULL
;
1107 start_knode
= &start
->p
->knode_bus
;
1108 klist_iter_init_node(&subsys
->p
->klist_devices
, &iter
->ki
, start_knode
);
1111 EXPORT_SYMBOL_GPL(subsys_dev_iter_init
);
1114 * subsys_dev_iter_next - iterate to the next device
1115 * @iter: subsys iterator to proceed
1117 * Proceed @iter to the next device and return it. Returns NULL if
1118 * iteration is complete.
1120 * The returned device is referenced and won't be released till
1121 * iterator is proceed to the next device or exited. The caller is
1122 * free to do whatever it wants to do with the device including
1123 * calling back into subsys code.
1125 struct device
*subsys_dev_iter_next(struct subsys_dev_iter
*iter
)
1127 struct klist_node
*knode
;
1131 knode
= klist_next(&iter
->ki
);
1134 dev
= container_of(knode
, struct device_private
, knode_bus
)->device
;
1135 if (!iter
->type
|| iter
->type
== dev
->type
)
1139 EXPORT_SYMBOL_GPL(subsys_dev_iter_next
);
1142 * subsys_dev_iter_exit - finish iteration
1143 * @iter: subsys iterator to finish
1145 * Finish an iteration. Always call this function after iteration is
1146 * complete whether the iteration ran till the end or not.
1148 void subsys_dev_iter_exit(struct subsys_dev_iter
*iter
)
1150 klist_iter_exit(&iter
->ki
);
1152 EXPORT_SYMBOL_GPL(subsys_dev_iter_exit
);
1154 int subsys_interface_register(struct subsys_interface
*sif
)
1156 struct bus_type
*subsys
;
1157 struct subsys_dev_iter iter
;
1160 if (!sif
|| !sif
->subsys
)
1163 subsys
= bus_get(sif
->subsys
);
1167 mutex_lock(&subsys
->p
->mutex
);
1168 list_add_tail(&sif
->node
, &subsys
->p
->interfaces
);
1170 subsys_dev_iter_init(&iter
, subsys
, NULL
, NULL
);
1171 while ((dev
= subsys_dev_iter_next(&iter
)))
1172 sif
->add_dev(dev
, sif
);
1173 subsys_dev_iter_exit(&iter
);
1175 mutex_unlock(&subsys
->p
->mutex
);
1179 EXPORT_SYMBOL_GPL(subsys_interface_register
);
1181 void subsys_interface_unregister(struct subsys_interface
*sif
)
1183 struct bus_type
*subsys
;
1184 struct subsys_dev_iter iter
;
1187 if (!sif
|| !sif
->subsys
)
1190 subsys
= sif
->subsys
;
1192 mutex_lock(&subsys
->p
->mutex
);
1193 list_del_init(&sif
->node
);
1194 if (sif
->remove_dev
) {
1195 subsys_dev_iter_init(&iter
, subsys
, NULL
, NULL
);
1196 while ((dev
= subsys_dev_iter_next(&iter
)))
1197 sif
->remove_dev(dev
, sif
);
1198 subsys_dev_iter_exit(&iter
);
1200 mutex_unlock(&subsys
->p
->mutex
);
1204 EXPORT_SYMBOL_GPL(subsys_interface_unregister
);
1206 static void system_root_device_release(struct device
*dev
)
1211 static int subsys_register(struct bus_type
*subsys
,
1212 const struct attribute_group
**groups
,
1213 struct kobject
*parent_of_root
)
1218 err
= bus_register(subsys
);
1222 dev
= kzalloc(sizeof(struct device
), GFP_KERNEL
);
1228 err
= dev_set_name(dev
, "%s", subsys
->name
);
1232 dev
->kobj
.parent
= parent_of_root
;
1233 dev
->groups
= groups
;
1234 dev
->release
= system_root_device_release
;
1236 err
= device_register(dev
);
1240 subsys
->dev_root
= dev
;
1249 bus_unregister(subsys
);
1254 * subsys_system_register - register a subsystem at /sys/devices/system/
1255 * @subsys: system subsystem
1256 * @groups: default attributes for the root device
1258 * All 'system' subsystems have a /sys/devices/system/<name> root device
1259 * with the name of the subsystem. The root device can carry subsystem-
1260 * wide attributes. All registered devices are below this single root
1261 * device and are named after the subsystem with a simple enumeration
1262 * number appended. The registered devices are not explicitely named;
1263 * only 'id' in the device needs to be set.
1265 * Do not use this interface for anything new, it exists for compatibility
1266 * with bad ideas only. New subsystems should use plain subsystems; and
1267 * add the subsystem-wide attributes should be added to the subsystem
1268 * directory itself and not some create fake root-device placed in
1269 * /sys/devices/system/<name>.
1271 int subsys_system_register(struct bus_type
*subsys
,
1272 const struct attribute_group
**groups
)
1274 return subsys_register(subsys
, groups
, &system_kset
->kobj
);
1276 EXPORT_SYMBOL_GPL(subsys_system_register
);
1279 * subsys_virtual_register - register a subsystem at /sys/devices/virtual/
1280 * @subsys: virtual subsystem
1281 * @groups: default attributes for the root device
1283 * All 'virtual' subsystems have a /sys/devices/system/<name> root device
1284 * with the name of the subystem. The root device can carry subsystem-wide
1285 * attributes. All registered devices are below this single root device.
1286 * There's no restriction on device naming. This is for kernel software
1287 * constructs which need sysfs interface.
1289 int subsys_virtual_register(struct bus_type
*subsys
,
1290 const struct attribute_group
**groups
)
1292 struct kobject
*virtual_dir
;
1294 virtual_dir
= virtual_device_parent(NULL
);
1298 return subsys_register(subsys
, groups
, virtual_dir
);
1300 EXPORT_SYMBOL_GPL(subsys_virtual_register
);
1302 int __init
buses_init(void)
1304 bus_kset
= kset_create_and_add("bus", &bus_uevent_ops
, NULL
);
1308 system_kset
= kset_create_and_add("system", NULL
, &devices_kset
->kobj
);