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
;
168 #ifdef CONFIG_HOTPLUG
169 /* Manually detach a device from its associated driver. */
170 static ssize_t
driver_unbind(struct device_driver
*drv
,
171 const char *buf
, size_t count
)
173 struct bus_type
*bus
= bus_get(drv
->bus
);
177 dev
= bus_find_device_by_name(bus
, NULL
, buf
);
178 if (dev
&& dev
->driver
== drv
) {
179 if (dev
->parent
) /* Needed for USB */
180 device_lock(dev
->parent
);
181 device_release_driver(dev
);
183 device_unlock(dev
->parent
);
190 static DRIVER_ATTR(unbind
, S_IWUSR
, NULL
, driver_unbind
);
193 * Manually attach a device to a driver.
194 * Note: the driver must want to bind to the device,
195 * it is not possible to override the driver's id table.
197 static ssize_t
driver_bind(struct device_driver
*drv
,
198 const char *buf
, size_t count
)
200 struct bus_type
*bus
= bus_get(drv
->bus
);
204 dev
= bus_find_device_by_name(bus
, NULL
, buf
);
205 if (dev
&& dev
->driver
== NULL
&& driver_match_device(drv
, dev
)) {
206 if (dev
->parent
) /* Needed for USB */
207 device_lock(dev
->parent
);
209 err
= driver_probe_device(drv
, dev
);
212 device_unlock(dev
->parent
);
217 } else if (err
== 0) {
218 /* driver didn't accept device */
226 static DRIVER_ATTR(bind
, S_IWUSR
, NULL
, driver_bind
);
228 static ssize_t
show_drivers_autoprobe(struct bus_type
*bus
, char *buf
)
230 return sprintf(buf
, "%d\n", bus
->p
->drivers_autoprobe
);
233 static ssize_t
store_drivers_autoprobe(struct bus_type
*bus
,
234 const char *buf
, size_t count
)
237 bus
->p
->drivers_autoprobe
= 0;
239 bus
->p
->drivers_autoprobe
= 1;
243 static ssize_t
store_drivers_probe(struct bus_type
*bus
,
244 const char *buf
, size_t count
)
248 dev
= bus_find_device_by_name(bus
, NULL
, buf
);
251 if (bus_rescan_devices_helper(dev
, NULL
) != 0)
257 static struct device
*next_device(struct klist_iter
*i
)
259 struct klist_node
*n
= klist_next(i
);
260 struct device
*dev
= NULL
;
261 struct device_private
*dev_prv
;
264 dev_prv
= to_device_private_bus(n
);
265 dev
= dev_prv
->device
;
271 * bus_for_each_dev - device iterator.
273 * @start: device to start iterating from.
274 * @data: data for the callback.
275 * @fn: function to be called for each device.
277 * Iterate over @bus's list of devices, and call @fn for each,
278 * passing it @data. If @start is not NULL, we use that device to
279 * begin iterating from.
281 * We check the return of @fn each time. If it returns anything
282 * other than 0, we break out and return that value.
284 * NOTE: The device that returns a non-zero value is not retained
285 * in any way, nor is its refcount incremented. If the caller needs
286 * to retain this data, it should do so, and increment the reference
287 * count in the supplied callback.
289 int bus_for_each_dev(struct bus_type
*bus
, struct device
*start
,
290 void *data
, int (*fn
)(struct device
*, void *))
299 klist_iter_init_node(&bus
->p
->klist_devices
, &i
,
300 (start
? &start
->p
->knode_bus
: NULL
));
301 while ((dev
= next_device(&i
)) && !error
)
302 error
= fn(dev
, data
);
306 EXPORT_SYMBOL_GPL(bus_for_each_dev
);
309 * bus_find_device - device iterator for locating a particular device.
311 * @start: Device to begin with
312 * @data: Data to pass to match function
313 * @match: Callback function to check device
315 * This is similar to the bus_for_each_dev() function above, but it
316 * returns a reference to a device that is 'found' for later use, as
317 * determined by the @match callback.
319 * The callback should return 0 if the device doesn't match and non-zero
320 * if it does. If the callback returns non-zero, this function will
321 * return to the caller and not iterate over any more devices.
323 struct device
*bus_find_device(struct bus_type
*bus
,
324 struct device
*start
, void *data
,
325 int (*match
)(struct device
*dev
, void *data
))
333 klist_iter_init_node(&bus
->p
->klist_devices
, &i
,
334 (start
? &start
->p
->knode_bus
: NULL
));
335 while ((dev
= next_device(&i
)))
336 if (match(dev
, data
) && get_device(dev
))
341 EXPORT_SYMBOL_GPL(bus_find_device
);
343 static int match_name(struct device
*dev
, void *data
)
345 const char *name
= data
;
347 return sysfs_streq(name
, dev_name(dev
));
351 * bus_find_device_by_name - device iterator for locating a particular device of a specific name
353 * @start: Device to begin with
354 * @name: name of the device to match
356 * This is similar to the bus_find_device() function above, but it handles
357 * searching by a name automatically, no need to write another strcmp matching
360 struct device
*bus_find_device_by_name(struct bus_type
*bus
,
361 struct device
*start
, const char *name
)
363 return bus_find_device(bus
, start
, (void *)name
, match_name
);
365 EXPORT_SYMBOL_GPL(bus_find_device_by_name
);
368 * subsys_find_device_by_id - find a device with a specific enumeration number
370 * @id: index 'id' in struct device
371 * @hint: device to check first
373 * Check the hint's next object and if it is a match return it directly,
374 * otherwise, fall back to a full list search. Either way a reference for
375 * the returned object is taken.
377 struct device
*subsys_find_device_by_id(struct bus_type
*subsys
, unsigned int id
,
387 klist_iter_init_node(&subsys
->p
->klist_devices
, &i
, &hint
->p
->knode_bus
);
388 dev
= next_device(&i
);
389 if (dev
&& dev
->id
== id
&& get_device(dev
)) {
396 klist_iter_init_node(&subsys
->p
->klist_devices
, &i
, NULL
);
397 while ((dev
= next_device(&i
))) {
398 if (dev
->id
== id
&& get_device(dev
)) {
406 EXPORT_SYMBOL_GPL(subsys_find_device_by_id
);
408 static struct device_driver
*next_driver(struct klist_iter
*i
)
410 struct klist_node
*n
= klist_next(i
);
411 struct driver_private
*drv_priv
;
414 drv_priv
= container_of(n
, struct driver_private
, knode_bus
);
415 return drv_priv
->driver
;
421 * bus_for_each_drv - driver iterator
422 * @bus: bus we're dealing with.
423 * @start: driver to start iterating on.
424 * @data: data to pass to the callback.
425 * @fn: function to call for each driver.
427 * This is nearly identical to the device iterator above.
428 * We iterate over each driver that belongs to @bus, and call
429 * @fn for each. If @fn returns anything but 0, we break out
430 * and return it. If @start is not NULL, we use it as the head
433 * NOTE: we don't return the driver that returns a non-zero
434 * value, nor do we leave the reference count incremented for that
435 * driver. If the caller needs to know that info, it must set it
436 * in the callback. It must also be sure to increment the refcount
437 * so it doesn't disappear before returning to the caller.
439 int bus_for_each_drv(struct bus_type
*bus
, struct device_driver
*start
,
440 void *data
, int (*fn
)(struct device_driver
*, void *))
443 struct device_driver
*drv
;
449 klist_iter_init_node(&bus
->p
->klist_drivers
, &i
,
450 start
? &start
->p
->knode_bus
: NULL
);
451 while ((drv
= next_driver(&i
)) && !error
)
452 error
= fn(drv
, data
);
456 EXPORT_SYMBOL_GPL(bus_for_each_drv
);
458 static int device_add_attrs(struct bus_type
*bus
, struct device
*dev
)
466 for (i
= 0; attr_name(bus
->dev_attrs
[i
]); i
++) {
467 error
= device_create_file(dev
, &bus
->dev_attrs
[i
]);
470 device_remove_file(dev
, &bus
->dev_attrs
[i
]);
477 static void device_remove_attrs(struct bus_type
*bus
, struct device
*dev
)
481 if (bus
->dev_attrs
) {
482 for (i
= 0; attr_name(bus
->dev_attrs
[i
]); i
++)
483 device_remove_file(dev
, &bus
->dev_attrs
[i
]);
488 * bus_add_device - add device to bus
489 * @dev: device being added
491 * - Add device's bus attributes.
492 * - Create links to device's bus.
493 * - Add the device to its bus's list of devices.
495 int bus_add_device(struct device
*dev
)
497 struct bus_type
*bus
= bus_get(dev
->bus
);
501 pr_debug("bus: '%s': add device %s\n", bus
->name
, dev_name(dev
));
502 error
= device_add_attrs(bus
, dev
);
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_attrs(bus
, dev
);
527 * bus_probe_device - probe drivers for a new device
528 * @dev: device to probe
530 * - Automatically probe for a driver if the bus allows it.
532 void bus_probe_device(struct device
*dev
)
534 struct bus_type
*bus
= dev
->bus
;
535 struct subsys_interface
*sif
;
541 if (bus
->p
->drivers_autoprobe
) {
542 ret
= device_attach(dev
);
546 mutex_lock(&bus
->p
->mutex
);
547 list_for_each_entry(sif
, &bus
->p
->interfaces
, node
)
549 sif
->add_dev(dev
, sif
);
550 mutex_unlock(&bus
->p
->mutex
);
554 * bus_remove_device - remove device from bus
555 * @dev: device to be removed
557 * - Remove device from all interfaces.
558 * - Remove symlink from bus' directory.
559 * - Delete device from bus's list.
560 * - Detach from its driver.
561 * - Drop reference taken in bus_add_device().
563 void bus_remove_device(struct device
*dev
)
565 struct bus_type
*bus
= dev
->bus
;
566 struct subsys_interface
*sif
;
571 mutex_lock(&bus
->p
->mutex
);
572 list_for_each_entry(sif
, &bus
->p
->interfaces
, node
)
574 sif
->remove_dev(dev
, sif
);
575 mutex_unlock(&bus
->p
->mutex
);
577 sysfs_remove_link(&dev
->kobj
, "subsystem");
578 sysfs_remove_link(&dev
->bus
->p
->devices_kset
->kobj
,
580 device_remove_attrs(dev
->bus
, dev
);
581 if (klist_node_attached(&dev
->p
->knode_bus
))
582 klist_del(&dev
->p
->knode_bus
);
584 pr_debug("bus: '%s': remove device %s\n",
585 dev
->bus
->name
, dev_name(dev
));
586 device_release_driver(dev
);
590 static int driver_add_attrs(struct bus_type
*bus
, struct device_driver
*drv
)
595 if (bus
->drv_attrs
) {
596 for (i
= 0; attr_name(bus
->drv_attrs
[i
]); i
++) {
597 error
= driver_create_file(drv
, &bus
->drv_attrs
[i
]);
606 driver_remove_file(drv
, &bus
->drv_attrs
[i
]);
610 static void driver_remove_attrs(struct bus_type
*bus
,
611 struct device_driver
*drv
)
615 if (bus
->drv_attrs
) {
616 for (i
= 0; attr_name(bus
->drv_attrs
[i
]); i
++)
617 driver_remove_file(drv
, &bus
->drv_attrs
[i
]);
621 #ifdef CONFIG_HOTPLUG
623 * Thanks to drivers making their tables __devinit, we can't allow manual
624 * bind and unbind from userspace unless CONFIG_HOTPLUG is enabled.
626 static int __must_check
add_bind_files(struct device_driver
*drv
)
630 ret
= driver_create_file(drv
, &driver_attr_unbind
);
632 ret
= driver_create_file(drv
, &driver_attr_bind
);
634 driver_remove_file(drv
, &driver_attr_unbind
);
639 static void remove_bind_files(struct device_driver
*drv
)
641 driver_remove_file(drv
, &driver_attr_bind
);
642 driver_remove_file(drv
, &driver_attr_unbind
);
645 static BUS_ATTR(drivers_probe
, S_IWUSR
, NULL
, store_drivers_probe
);
646 static BUS_ATTR(drivers_autoprobe
, S_IWUSR
| S_IRUGO
,
647 show_drivers_autoprobe
, store_drivers_autoprobe
);
649 static int add_probe_files(struct bus_type
*bus
)
653 retval
= bus_create_file(bus
, &bus_attr_drivers_probe
);
657 retval
= bus_create_file(bus
, &bus_attr_drivers_autoprobe
);
659 bus_remove_file(bus
, &bus_attr_drivers_probe
);
664 static void remove_probe_files(struct bus_type
*bus
)
666 bus_remove_file(bus
, &bus_attr_drivers_autoprobe
);
667 bus_remove_file(bus
, &bus_attr_drivers_probe
);
670 static inline int add_bind_files(struct device_driver
*drv
) { return 0; }
671 static inline void remove_bind_files(struct device_driver
*drv
) {}
672 static inline int add_probe_files(struct bus_type
*bus
) { return 0; }
673 static inline void remove_probe_files(struct bus_type
*bus
) {}
676 static ssize_t
driver_uevent_store(struct device_driver
*drv
,
677 const char *buf
, size_t count
)
679 enum kobject_action action
;
681 if (kobject_action_type(buf
, count
, &action
) == 0)
682 kobject_uevent(&drv
->p
->kobj
, action
);
685 static DRIVER_ATTR(uevent
, S_IWUSR
, NULL
, driver_uevent_store
);
688 * bus_add_driver - Add a driver to the bus.
691 int bus_add_driver(struct device_driver
*drv
)
693 struct bus_type
*bus
;
694 struct driver_private
*priv
;
697 bus
= bus_get(drv
->bus
);
701 pr_debug("bus: '%s': add driver %s\n", bus
->name
, drv
->name
);
703 priv
= kzalloc(sizeof(*priv
), GFP_KERNEL
);
708 klist_init(&priv
->klist_devices
, NULL
, NULL
);
711 priv
->kobj
.kset
= bus
->p
->drivers_kset
;
712 error
= kobject_init_and_add(&priv
->kobj
, &driver_ktype
, NULL
,
717 if (drv
->bus
->p
->drivers_autoprobe
) {
718 error
= driver_attach(drv
);
722 klist_add_tail(&priv
->knode_bus
, &bus
->p
->klist_drivers
);
723 module_add_driver(drv
->owner
, drv
);
725 error
= driver_create_file(drv
, &driver_attr_uevent
);
727 printk(KERN_ERR
"%s: uevent attr (%s) failed\n",
728 __func__
, drv
->name
);
730 error
= driver_add_attrs(bus
, drv
);
732 /* How the hell do we get out of this pickle? Give up */
733 printk(KERN_ERR
"%s: driver_add_attrs(%s) failed\n",
734 __func__
, drv
->name
);
737 if (!drv
->suppress_bind_attrs
) {
738 error
= add_bind_files(drv
);
741 printk(KERN_ERR
"%s: add_bind_files(%s) failed\n",
742 __func__
, drv
->name
);
746 kobject_uevent(&priv
->kobj
, KOBJ_ADD
);
750 kobject_put(&priv
->kobj
);
759 * bus_remove_driver - delete driver from bus's knowledge.
762 * Detach the driver from the devices it controls, and remove
763 * it from its bus's list of drivers. Finally, we drop the reference
764 * to the bus we took in bus_add_driver().
766 void bus_remove_driver(struct device_driver
*drv
)
771 if (!drv
->suppress_bind_attrs
)
772 remove_bind_files(drv
);
773 driver_remove_attrs(drv
->bus
, drv
);
774 driver_remove_file(drv
, &driver_attr_uevent
);
775 klist_remove(&drv
->p
->knode_bus
);
776 pr_debug("bus: '%s': remove driver %s\n", drv
->bus
->name
, drv
->name
);
778 module_remove_driver(drv
);
779 kobject_put(&drv
->p
->kobj
);
783 /* Helper for bus_rescan_devices's iter */
784 static int __must_check
bus_rescan_devices_helper(struct device
*dev
,
790 if (dev
->parent
) /* Needed for USB */
791 device_lock(dev
->parent
);
792 ret
= device_attach(dev
);
794 device_unlock(dev
->parent
);
796 return ret
< 0 ? ret
: 0;
800 * bus_rescan_devices - rescan devices on the bus for possible drivers
801 * @bus: the bus to scan.
803 * This function will look for devices on the bus with no driver
804 * attached and rescan it against existing drivers to see if it matches
805 * any by calling device_attach() for the unbound devices.
807 int bus_rescan_devices(struct bus_type
*bus
)
809 return bus_for_each_dev(bus
, NULL
, NULL
, bus_rescan_devices_helper
);
811 EXPORT_SYMBOL_GPL(bus_rescan_devices
);
814 * device_reprobe - remove driver for a device and probe for a new driver
815 * @dev: the device to reprobe
817 * This function detaches the attached driver (if any) for the given
818 * device and restarts the driver probing process. It is intended
819 * to use if probing criteria changed during a devices lifetime and
820 * driver attachment should change accordingly.
822 int device_reprobe(struct device
*dev
)
825 if (dev
->parent
) /* Needed for USB */
826 device_lock(dev
->parent
);
827 device_release_driver(dev
);
829 device_unlock(dev
->parent
);
831 return bus_rescan_devices_helper(dev
, NULL
);
833 EXPORT_SYMBOL_GPL(device_reprobe
);
836 * find_bus - locate bus by name.
837 * @name: name of bus.
839 * Call kset_find_obj() to iterate over list of buses to
840 * find a bus by name. Return bus if found.
842 * Note that kset_find_obj increments bus' reference count.
845 struct bus_type
*find_bus(char *name
)
847 struct kobject
*k
= kset_find_obj(bus_kset
, name
);
848 return k
? to_bus(k
) : NULL
;
854 * bus_add_attrs - Add default attributes for this bus.
855 * @bus: Bus that has just been registered.
858 static int bus_add_attrs(struct bus_type
*bus
)
863 if (bus
->bus_attrs
) {
864 for (i
= 0; attr_name(bus
->bus_attrs
[i
]); i
++) {
865 error
= bus_create_file(bus
, &bus
->bus_attrs
[i
]);
874 bus_remove_file(bus
, &bus
->bus_attrs
[i
]);
878 static void bus_remove_attrs(struct bus_type
*bus
)
882 if (bus
->bus_attrs
) {
883 for (i
= 0; attr_name(bus
->bus_attrs
[i
]); i
++)
884 bus_remove_file(bus
, &bus
->bus_attrs
[i
]);
888 static void klist_devices_get(struct klist_node
*n
)
890 struct device_private
*dev_prv
= to_device_private_bus(n
);
891 struct device
*dev
= dev_prv
->device
;
896 static void klist_devices_put(struct klist_node
*n
)
898 struct device_private
*dev_prv
= to_device_private_bus(n
);
899 struct device
*dev
= dev_prv
->device
;
904 static ssize_t
bus_uevent_store(struct bus_type
*bus
,
905 const char *buf
, size_t count
)
907 enum kobject_action action
;
909 if (kobject_action_type(buf
, count
, &action
) == 0)
910 kobject_uevent(&bus
->p
->subsys
.kobj
, action
);
913 static BUS_ATTR(uevent
, S_IWUSR
, NULL
, bus_uevent_store
);
916 * __bus_register - register a driver-core subsystem
917 * @bus: bus to register
918 * @key: lockdep class key
920 * Once we have that, we register the bus with the kobject
921 * infrastructure, then register the children subsystems it has:
922 * the devices and drivers that belong to the subsystem.
924 int __bus_register(struct bus_type
*bus
, struct lock_class_key
*key
)
927 struct subsys_private
*priv
;
929 priv
= kzalloc(sizeof(struct subsys_private
), GFP_KERNEL
);
936 BLOCKING_INIT_NOTIFIER_HEAD(&priv
->bus_notifier
);
938 retval
= kobject_set_name(&priv
->subsys
.kobj
, "%s", bus
->name
);
942 priv
->subsys
.kobj
.kset
= bus_kset
;
943 priv
->subsys
.kobj
.ktype
= &bus_ktype
;
944 priv
->drivers_autoprobe
= 1;
946 retval
= kset_register(&priv
->subsys
);
950 retval
= bus_create_file(bus
, &bus_attr_uevent
);
952 goto bus_uevent_fail
;
954 priv
->devices_kset
= kset_create_and_add("devices", NULL
,
956 if (!priv
->devices_kset
) {
958 goto bus_devices_fail
;
961 priv
->drivers_kset
= kset_create_and_add("drivers", NULL
,
963 if (!priv
->drivers_kset
) {
965 goto bus_drivers_fail
;
968 INIT_LIST_HEAD(&priv
->interfaces
);
969 __mutex_init(&priv
->mutex
, "subsys mutex", key
);
970 klist_init(&priv
->klist_devices
, klist_devices_get
, klist_devices_put
);
971 klist_init(&priv
->klist_drivers
, NULL
, NULL
);
973 retval
= add_probe_files(bus
);
975 goto bus_probe_files_fail
;
977 retval
= bus_add_attrs(bus
);
981 pr_debug("bus: '%s': registered\n", bus
->name
);
985 remove_probe_files(bus
);
986 bus_probe_files_fail
:
987 kset_unregister(bus
->p
->drivers_kset
);
989 kset_unregister(bus
->p
->devices_kset
);
991 bus_remove_file(bus
, &bus_attr_uevent
);
993 kset_unregister(&bus
->p
->subsys
);
999 EXPORT_SYMBOL_GPL(__bus_register
);
1002 * bus_unregister - remove a bus from the system
1005 * Unregister the child subsystems and the bus itself.
1006 * Finally, we call bus_put() to release the refcount
1008 void bus_unregister(struct bus_type
*bus
)
1010 pr_debug("bus: '%s': unregistering\n", bus
->name
);
1012 device_unregister(bus
->dev_root
);
1013 bus_remove_attrs(bus
);
1014 remove_probe_files(bus
);
1015 kset_unregister(bus
->p
->drivers_kset
);
1016 kset_unregister(bus
->p
->devices_kset
);
1017 bus_remove_file(bus
, &bus_attr_uevent
);
1018 kset_unregister(&bus
->p
->subsys
);
1022 EXPORT_SYMBOL_GPL(bus_unregister
);
1024 int bus_register_notifier(struct bus_type
*bus
, struct notifier_block
*nb
)
1026 return blocking_notifier_chain_register(&bus
->p
->bus_notifier
, nb
);
1028 EXPORT_SYMBOL_GPL(bus_register_notifier
);
1030 int bus_unregister_notifier(struct bus_type
*bus
, struct notifier_block
*nb
)
1032 return blocking_notifier_chain_unregister(&bus
->p
->bus_notifier
, nb
);
1034 EXPORT_SYMBOL_GPL(bus_unregister_notifier
);
1036 struct kset
*bus_get_kset(struct bus_type
*bus
)
1038 return &bus
->p
->subsys
;
1040 EXPORT_SYMBOL_GPL(bus_get_kset
);
1042 struct klist
*bus_get_device_klist(struct bus_type
*bus
)
1044 return &bus
->p
->klist_devices
;
1046 EXPORT_SYMBOL_GPL(bus_get_device_klist
);
1049 * Yes, this forcibly breaks the klist abstraction temporarily. It
1050 * just wants to sort the klist, not change reference counts and
1051 * take/drop locks rapidly in the process. It does all this while
1052 * holding the lock for the list, so objects can't otherwise be
1053 * added/removed while we're swizzling.
1055 static void device_insertion_sort_klist(struct device
*a
, struct list_head
*list
,
1056 int (*compare
)(const struct device
*a
,
1057 const struct device
*b
))
1059 struct list_head
*pos
;
1060 struct klist_node
*n
;
1061 struct device_private
*dev_prv
;
1064 list_for_each(pos
, list
) {
1065 n
= container_of(pos
, struct klist_node
, n_node
);
1066 dev_prv
= to_device_private_bus(n
);
1067 b
= dev_prv
->device
;
1068 if (compare(a
, b
) <= 0) {
1069 list_move_tail(&a
->p
->knode_bus
.n_node
,
1070 &b
->p
->knode_bus
.n_node
);
1074 list_move_tail(&a
->p
->knode_bus
.n_node
, list
);
1077 void bus_sort_breadthfirst(struct bus_type
*bus
,
1078 int (*compare
)(const struct device
*a
,
1079 const struct device
*b
))
1081 LIST_HEAD(sorted_devices
);
1082 struct list_head
*pos
, *tmp
;
1083 struct klist_node
*n
;
1084 struct device_private
*dev_prv
;
1086 struct klist
*device_klist
;
1088 device_klist
= bus_get_device_klist(bus
);
1090 spin_lock(&device_klist
->k_lock
);
1091 list_for_each_safe(pos
, tmp
, &device_klist
->k_list
) {
1092 n
= container_of(pos
, struct klist_node
, n_node
);
1093 dev_prv
= to_device_private_bus(n
);
1094 dev
= dev_prv
->device
;
1095 device_insertion_sort_klist(dev
, &sorted_devices
, compare
);
1097 list_splice(&sorted_devices
, &device_klist
->k_list
);
1098 spin_unlock(&device_klist
->k_lock
);
1100 EXPORT_SYMBOL_GPL(bus_sort_breadthfirst
);
1103 * subsys_dev_iter_init - initialize subsys device iterator
1104 * @iter: subsys iterator to initialize
1105 * @subsys: the subsys we wanna iterate over
1106 * @start: the device to start iterating from, if any
1107 * @type: device_type of the devices to iterate over, NULL for all
1109 * Initialize subsys iterator @iter such that it iterates over devices
1110 * of @subsys. If @start is set, the list iteration will start there,
1111 * otherwise if it is NULL, the iteration starts at the beginning of
1114 void subsys_dev_iter_init(struct subsys_dev_iter
*iter
, struct bus_type
*subsys
,
1115 struct device
*start
, const struct device_type
*type
)
1117 struct klist_node
*start_knode
= NULL
;
1120 start_knode
= &start
->p
->knode_bus
;
1121 klist_iter_init_node(&subsys
->p
->klist_devices
, &iter
->ki
, start_knode
);
1124 EXPORT_SYMBOL_GPL(subsys_dev_iter_init
);
1127 * subsys_dev_iter_next - iterate to the next device
1128 * @iter: subsys iterator to proceed
1130 * Proceed @iter to the next device and return it. Returns NULL if
1131 * iteration is complete.
1133 * The returned device is referenced and won't be released till
1134 * iterator is proceed to the next device or exited. The caller is
1135 * free to do whatever it wants to do with the device including
1136 * calling back into subsys code.
1138 struct device
*subsys_dev_iter_next(struct subsys_dev_iter
*iter
)
1140 struct klist_node
*knode
;
1144 knode
= klist_next(&iter
->ki
);
1147 dev
= container_of(knode
, struct device_private
, knode_bus
)->device
;
1148 if (!iter
->type
|| iter
->type
== dev
->type
)
1152 EXPORT_SYMBOL_GPL(subsys_dev_iter_next
);
1155 * subsys_dev_iter_exit - finish iteration
1156 * @iter: subsys iterator to finish
1158 * Finish an iteration. Always call this function after iteration is
1159 * complete whether the iteration ran till the end or not.
1161 void subsys_dev_iter_exit(struct subsys_dev_iter
*iter
)
1163 klist_iter_exit(&iter
->ki
);
1165 EXPORT_SYMBOL_GPL(subsys_dev_iter_exit
);
1167 int subsys_interface_register(struct subsys_interface
*sif
)
1169 struct bus_type
*subsys
;
1170 struct subsys_dev_iter iter
;
1173 if (!sif
|| !sif
->subsys
)
1176 subsys
= bus_get(sif
->subsys
);
1180 mutex_lock(&subsys
->p
->mutex
);
1181 list_add_tail(&sif
->node
, &subsys
->p
->interfaces
);
1183 subsys_dev_iter_init(&iter
, subsys
, NULL
, NULL
);
1184 while ((dev
= subsys_dev_iter_next(&iter
)))
1185 sif
->add_dev(dev
, sif
);
1186 subsys_dev_iter_exit(&iter
);
1188 mutex_unlock(&subsys
->p
->mutex
);
1192 EXPORT_SYMBOL_GPL(subsys_interface_register
);
1194 void subsys_interface_unregister(struct subsys_interface
*sif
)
1196 struct bus_type
*subsys
;
1197 struct subsys_dev_iter iter
;
1200 if (!sif
|| !sif
->subsys
)
1203 subsys
= sif
->subsys
;
1205 mutex_lock(&subsys
->p
->mutex
);
1206 list_del_init(&sif
->node
);
1207 if (sif
->remove_dev
) {
1208 subsys_dev_iter_init(&iter
, subsys
, NULL
, NULL
);
1209 while ((dev
= subsys_dev_iter_next(&iter
)))
1210 sif
->remove_dev(dev
, sif
);
1211 subsys_dev_iter_exit(&iter
);
1213 mutex_unlock(&subsys
->p
->mutex
);
1217 EXPORT_SYMBOL_GPL(subsys_interface_unregister
);
1219 static void system_root_device_release(struct device
*dev
)
1224 * subsys_system_register - register a subsystem at /sys/devices/system/
1225 * @subsys: system subsystem
1226 * @groups: default attributes for the root device
1228 * All 'system' subsystems have a /sys/devices/system/<name> root device
1229 * with the name of the subsystem. The root device can carry subsystem-
1230 * wide attributes. All registered devices are below this single root
1231 * device and are named after the subsystem with a simple enumeration
1232 * number appended. The registered devices are not explicitely named;
1233 * only 'id' in the device needs to be set.
1235 * Do not use this interface for anything new, it exists for compatibility
1236 * with bad ideas only. New subsystems should use plain subsystems; and
1237 * add the subsystem-wide attributes should be added to the subsystem
1238 * directory itself and not some create fake root-device placed in
1239 * /sys/devices/system/<name>.
1241 int subsys_system_register(struct bus_type
*subsys
,
1242 const struct attribute_group
**groups
)
1247 err
= bus_register(subsys
);
1251 dev
= kzalloc(sizeof(struct device
), GFP_KERNEL
);
1257 err
= dev_set_name(dev
, "%s", subsys
->name
);
1261 dev
->kobj
.parent
= &system_kset
->kobj
;
1262 dev
->groups
= groups
;
1263 dev
->release
= system_root_device_release
;
1265 err
= device_register(dev
);
1269 subsys
->dev_root
= dev
;
1278 bus_unregister(subsys
);
1281 EXPORT_SYMBOL_GPL(subsys_system_register
);
1283 int __init
buses_init(void)
1285 bus_kset
= kset_create_and_add("bus", &bus_uevent_ops
, NULL
);
1289 system_kset
= kset_create_and_add("system", NULL
, &devices_kset
->kobj
);