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1/*
2 * bus.c - bus driver management
3 *
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.
8 *
9 * This file is released under the GPLv2
10 *
11 */
12
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 "base.h"
20#include "power/power.h"
21
22#define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
23
24/*
25 * sysfs bindings for drivers
26 */
27
28#define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
29
30
31static int __must_check bus_rescan_devices_helper(struct device *dev,
32 void *data);
33
34static struct bus_type *bus_get(struct bus_type *bus)
35{
36 if (bus) {
37 kset_get(&bus->p->subsys);
38 return bus;
39 }
40 return NULL;
41}
42
43static void bus_put(struct bus_type *bus)
44{
45 if (bus)
46 kset_put(&bus->p->subsys);
47}
48
49static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr,
50 char *buf)
51{
52 struct driver_attribute *drv_attr = to_drv_attr(attr);
53 struct driver_private *drv_priv = to_driver(kobj);
54 ssize_t ret = -EIO;
55
56 if (drv_attr->show)
57 ret = drv_attr->show(drv_priv->driver, buf);
58 return ret;
59}
60
61static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr,
62 const char *buf, size_t count)
63{
64 struct driver_attribute *drv_attr = to_drv_attr(attr);
65 struct driver_private *drv_priv = to_driver(kobj);
66 ssize_t ret = -EIO;
67
68 if (drv_attr->store)
69 ret = drv_attr->store(drv_priv->driver, buf, count);
70 return ret;
71}
72
73static const struct sysfs_ops driver_sysfs_ops = {
74 .show = drv_attr_show,
75 .store = drv_attr_store,
76};
77
78static void driver_release(struct kobject *kobj)
79{
80 struct driver_private *drv_priv = to_driver(kobj);
81
82 pr_debug("driver: '%s': %s\n", kobject_name(kobj), __func__);
83 kfree(drv_priv);
84}
85
86static struct kobj_type driver_ktype = {
87 .sysfs_ops = &driver_sysfs_ops,
88 .release = driver_release,
89};
90
91/*
92 * sysfs bindings for buses
93 */
94static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr,
95 char *buf)
96{
97 struct bus_attribute *bus_attr = to_bus_attr(attr);
98 struct subsys_private *subsys_priv = to_subsys_private(kobj);
99 ssize_t ret = 0;
100
101 if (bus_attr->show)
102 ret = bus_attr->show(subsys_priv->bus, buf);
103 return ret;
104}
105
106static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr,
107 const char *buf, size_t count)
108{
109 struct bus_attribute *bus_attr = to_bus_attr(attr);
110 struct subsys_private *subsys_priv = to_subsys_private(kobj);
111 ssize_t ret = 0;
112
113 if (bus_attr->store)
114 ret = bus_attr->store(subsys_priv->bus, buf, count);
115 return ret;
116}
117
118static const struct sysfs_ops bus_sysfs_ops = {
119 .show = bus_attr_show,
120 .store = bus_attr_store,
121};
122
123int bus_create_file(struct bus_type *bus, struct bus_attribute *attr)
124{
125 int error;
126 if (bus_get(bus)) {
127 error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr);
128 bus_put(bus);
129 } else
130 error = -EINVAL;
131 return error;
132}
133EXPORT_SYMBOL_GPL(bus_create_file);
134
135void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr)
136{
137 if (bus_get(bus)) {
138 sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr);
139 bus_put(bus);
140 }
141}
142EXPORT_SYMBOL_GPL(bus_remove_file);
143
144static struct kobj_type bus_ktype = {
145 .sysfs_ops = &bus_sysfs_ops,
146};
147
148static int bus_uevent_filter(struct kset *kset, struct kobject *kobj)
149{
150 struct kobj_type *ktype = get_ktype(kobj);
151
152 if (ktype == &bus_ktype)
153 return 1;
154 return 0;
155}
156
157static const struct kset_uevent_ops bus_uevent_ops = {
158 .filter = bus_uevent_filter,
159};
160
161static struct kset *bus_kset;
162
163
164#ifdef CONFIG_HOTPLUG
165/* Manually detach a device from its associated driver. */
166static ssize_t driver_unbind(struct device_driver *drv,
167 const char *buf, size_t count)
168{
169 struct bus_type *bus = bus_get(drv->bus);
170 struct device *dev;
171 int err = -ENODEV;
172
173 dev = bus_find_device_by_name(bus, NULL, buf);
174 if (dev && dev->driver == drv) {
175 if (dev->parent) /* Needed for USB */
176 device_lock(dev->parent);
177 device_release_driver(dev);
178 if (dev->parent)
179 device_unlock(dev->parent);
180 err = count;
181 }
182 put_device(dev);
183 bus_put(bus);
184 return err;
185}
186static DRIVER_ATTR(unbind, S_IWUSR, NULL, driver_unbind);
187
188/*
189 * Manually attach a device to a driver.
190 * Note: the driver must want to bind to the device,
191 * it is not possible to override the driver's id table.
192 */
193static ssize_t driver_bind(struct device_driver *drv,
194 const char *buf, size_t count)
195{
196 struct bus_type *bus = bus_get(drv->bus);
197 struct device *dev;
198 int err = -ENODEV;
199
200 dev = bus_find_device_by_name(bus, NULL, buf);
201 if (dev && dev->driver == NULL && driver_match_device(drv, dev)) {
202 if (dev->parent) /* Needed for USB */
203 device_lock(dev->parent);
204 device_lock(dev);
205 err = driver_probe_device(drv, dev);
206 device_unlock(dev);
207 if (dev->parent)
208 device_unlock(dev->parent);
209
210 if (err > 0) {
211 /* success */
212 err = count;
213 } else if (err == 0) {
214 /* driver didn't accept device */
215 err = -ENODEV;
216 }
217 }
218 put_device(dev);
219 bus_put(bus);
220 return err;
221}
222static DRIVER_ATTR(bind, S_IWUSR, NULL, driver_bind);
223
224static ssize_t show_drivers_autoprobe(struct bus_type *bus, char *buf)
225{
226 return sprintf(buf, "%d\n", bus->p->drivers_autoprobe);
227}
228
229static ssize_t store_drivers_autoprobe(struct bus_type *bus,
230 const char *buf, size_t count)
231{
232 if (buf[0] == '0')
233 bus->p->drivers_autoprobe = 0;
234 else
235 bus->p->drivers_autoprobe = 1;
236 return count;
237}
238
239static ssize_t store_drivers_probe(struct bus_type *bus,
240 const char *buf, size_t count)
241{
242 struct device *dev;
243
244 dev = bus_find_device_by_name(bus, NULL, buf);
245 if (!dev)
246 return -ENODEV;
247 if (bus_rescan_devices_helper(dev, NULL) != 0)
248 return -EINVAL;
249 return count;
250}
251#endif
252
253static struct device *next_device(struct klist_iter *i)
254{
255 struct klist_node *n = klist_next(i);
256 struct device *dev = NULL;
257 struct device_private *dev_prv;
258
259 if (n) {
260 dev_prv = to_device_private_bus(n);
261 dev = dev_prv->device;
262 }
263 return dev;
264}
265
266/**
267 * bus_for_each_dev - device iterator.
268 * @bus: bus type.
269 * @start: device to start iterating from.
270 * @data: data for the callback.
271 * @fn: function to be called for each device.
272 *
273 * Iterate over @bus's list of devices, and call @fn for each,
274 * passing it @data. If @start is not NULL, we use that device to
275 * begin iterating from.
276 *
277 * We check the return of @fn each time. If it returns anything
278 * other than 0, we break out and return that value.
279 *
280 * NOTE: The device that returns a non-zero value is not retained
281 * in any way, nor is its refcount incremented. If the caller needs
282 * to retain this data, it should do so, and increment the reference
283 * count in the supplied callback.
284 */
285int bus_for_each_dev(struct bus_type *bus, struct device *start,
286 void *data, int (*fn)(struct device *, void *))
287{
288 struct klist_iter i;
289 struct device *dev;
290 int error = 0;
291
292 if (!bus)
293 return -EINVAL;
294
295 klist_iter_init_node(&bus->p->klist_devices, &i,
296 (start ? &start->p->knode_bus : NULL));
297 while ((dev = next_device(&i)) && !error)
298 error = fn(dev, data);
299 klist_iter_exit(&i);
300 return error;
301}
302EXPORT_SYMBOL_GPL(bus_for_each_dev);
303
304/**
305 * bus_find_device - device iterator for locating a particular device.
306 * @bus: bus type
307 * @start: Device to begin with
308 * @data: Data to pass to match function
309 * @match: Callback function to check device
310 *
311 * This is similar to the bus_for_each_dev() function above, but it
312 * returns a reference to a device that is 'found' for later use, as
313 * determined by the @match callback.
314 *
315 * The callback should return 0 if the device doesn't match and non-zero
316 * if it does. If the callback returns non-zero, this function will
317 * return to the caller and not iterate over any more devices.
318 */
319struct device *bus_find_device(struct bus_type *bus,
320 struct device *start, void *data,
321 int (*match)(struct device *dev, void *data))
322{
323 struct klist_iter i;
324 struct device *dev;
325
326 if (!bus)
327 return NULL;
328
329 klist_iter_init_node(&bus->p->klist_devices, &i,
330 (start ? &start->p->knode_bus : NULL));
331 while ((dev = next_device(&i)))
332 if (match(dev, data) && get_device(dev))
333 break;
334 klist_iter_exit(&i);
335 return dev;
336}
337EXPORT_SYMBOL_GPL(bus_find_device);
338
339static int match_name(struct device *dev, void *data)
340{
341 const char *name = data;
342
343 return sysfs_streq(name, dev_name(dev));
344}
345
346/**
347 * bus_find_device_by_name - device iterator for locating a particular device of a specific name
348 * @bus: bus type
349 * @start: Device to begin with
350 * @name: name of the device to match
351 *
352 * This is similar to the bus_find_device() function above, but it handles
353 * searching by a name automatically, no need to write another strcmp matching
354 * function.
355 */
356struct device *bus_find_device_by_name(struct bus_type *bus,
357 struct device *start, const char *name)
358{
359 return bus_find_device(bus, start, (void *)name, match_name);
360}
361EXPORT_SYMBOL_GPL(bus_find_device_by_name);
362
363static struct device_driver *next_driver(struct klist_iter *i)
364{
365 struct klist_node *n = klist_next(i);
366 struct driver_private *drv_priv;
367
368 if (n) {
369 drv_priv = container_of(n, struct driver_private, knode_bus);
370 return drv_priv->driver;
371 }
372 return NULL;
373}
374
375/**
376 * bus_for_each_drv - driver iterator
377 * @bus: bus we're dealing with.
378 * @start: driver to start iterating on.
379 * @data: data to pass to the callback.
380 * @fn: function to call for each driver.
381 *
382 * This is nearly identical to the device iterator above.
383 * We iterate over each driver that belongs to @bus, and call
384 * @fn for each. If @fn returns anything but 0, we break out
385 * and return it. If @start is not NULL, we use it as the head
386 * of the list.
387 *
388 * NOTE: we don't return the driver that returns a non-zero
389 * value, nor do we leave the reference count incremented for that
390 * driver. If the caller needs to know that info, it must set it
391 * in the callback. It must also be sure to increment the refcount
392 * so it doesn't disappear before returning to the caller.
393 */
394int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
395 void *data, int (*fn)(struct device_driver *, void *))
396{
397 struct klist_iter i;
398 struct device_driver *drv;
399 int error = 0;
400
401 if (!bus)
402 return -EINVAL;
403
404 klist_iter_init_node(&bus->p->klist_drivers, &i,
405 start ? &start->p->knode_bus : NULL);
406 while ((drv = next_driver(&i)) && !error)
407 error = fn(drv, data);
408 klist_iter_exit(&i);
409 return error;
410}
411EXPORT_SYMBOL_GPL(bus_for_each_drv);
412
413static int device_add_attrs(struct bus_type *bus, struct device *dev)
414{
415 int error = 0;
416 int i;
417
418 if (!bus->dev_attrs)
419 return 0;
420
421 for (i = 0; attr_name(bus->dev_attrs[i]); i++) {
422 error = device_create_file(dev, &bus->dev_attrs[i]);
423 if (error) {
424 while (--i >= 0)
425 device_remove_file(dev, &bus->dev_attrs[i]);
426 break;
427 }
428 }
429 return error;
430}
431
432static void device_remove_attrs(struct bus_type *bus, struct device *dev)
433{
434 int i;
435
436 if (bus->dev_attrs) {
437 for (i = 0; attr_name(bus->dev_attrs[i]); i++)
438 device_remove_file(dev, &bus->dev_attrs[i]);
439 }
440}
441
442/**
443 * bus_add_device - add device to bus
444 * @dev: device being added
445 *
446 * - Add device's bus attributes.
447 * - Create links to device's bus.
448 * - Add the device to its bus's list of devices.
449 */
450int bus_add_device(struct device *dev)
451{
452 struct bus_type *bus = bus_get(dev->bus);
453 int error = 0;
454
455 if (bus) {
456 pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev));
457 error = device_add_attrs(bus, dev);
458 if (error)
459 goto out_put;
460 error = sysfs_create_link(&bus->p->devices_kset->kobj,
461 &dev->kobj, dev_name(dev));
462 if (error)
463 goto out_id;
464 error = sysfs_create_link(&dev->kobj,
465 &dev->bus->p->subsys.kobj, "subsystem");
466 if (error)
467 goto out_subsys;
468 klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices);
469 }
470 return 0;
471
472out_subsys:
473 sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev));
474out_id:
475 device_remove_attrs(bus, dev);
476out_put:
477 bus_put(dev->bus);
478 return error;
479}
480
481/**
482 * bus_probe_device - probe drivers for a new device
483 * @dev: device to probe
484 *
485 * - Automatically probe for a driver if the bus allows it.
486 */
487void bus_probe_device(struct device *dev)
488{
489 struct bus_type *bus = dev->bus;
490 int ret;
491
492 if (bus && bus->p->drivers_autoprobe) {
493 ret = device_attach(dev);
494 WARN_ON(ret < 0);
495 }
496}
497
498/**
499 * bus_remove_device - remove device from bus
500 * @dev: device to be removed
501 *
502 * - Remove symlink from bus's directory.
503 * - Delete device from bus's list.
504 * - Detach from its driver.
505 * - Drop reference taken in bus_add_device().
506 */
507void bus_remove_device(struct device *dev)
508{
509 if (dev->bus) {
510 sysfs_remove_link(&dev->kobj, "subsystem");
511 sysfs_remove_link(&dev->bus->p->devices_kset->kobj,
512 dev_name(dev));
513 device_remove_attrs(dev->bus, dev);
514 if (klist_node_attached(&dev->p->knode_bus))
515 klist_del(&dev->p->knode_bus);
516
517 pr_debug("bus: '%s': remove device %s\n",
518 dev->bus->name, dev_name(dev));
519 device_release_driver(dev);
520 bus_put(dev->bus);
521 }
522}
523
524static int driver_add_attrs(struct bus_type *bus, struct device_driver *drv)
525{
526 int error = 0;
527 int i;
528
529 if (bus->drv_attrs) {
530 for (i = 0; attr_name(bus->drv_attrs[i]); i++) {
531 error = driver_create_file(drv, &bus->drv_attrs[i]);
532 if (error)
533 goto err;
534 }
535 }
536done:
537 return error;
538err:
539 while (--i >= 0)
540 driver_remove_file(drv, &bus->drv_attrs[i]);
541 goto done;
542}
543
544static void driver_remove_attrs(struct bus_type *bus,
545 struct device_driver *drv)
546{
547 int i;
548
549 if (bus->drv_attrs) {
550 for (i = 0; attr_name(bus->drv_attrs[i]); i++)
551 driver_remove_file(drv, &bus->drv_attrs[i]);
552 }
553}
554
555#ifdef CONFIG_HOTPLUG
556/*
557 * Thanks to drivers making their tables __devinit, we can't allow manual
558 * bind and unbind from userspace unless CONFIG_HOTPLUG is enabled.
559 */
560static int __must_check add_bind_files(struct device_driver *drv)
561{
562 int ret;
563
564 ret = driver_create_file(drv, &driver_attr_unbind);
565 if (ret == 0) {
566 ret = driver_create_file(drv, &driver_attr_bind);
567 if (ret)
568 driver_remove_file(drv, &driver_attr_unbind);
569 }
570 return ret;
571}
572
573static void remove_bind_files(struct device_driver *drv)
574{
575 driver_remove_file(drv, &driver_attr_bind);
576 driver_remove_file(drv, &driver_attr_unbind);
577}
578
579static BUS_ATTR(drivers_probe, S_IWUSR, NULL, store_drivers_probe);
580static BUS_ATTR(drivers_autoprobe, S_IWUSR | S_IRUGO,
581 show_drivers_autoprobe, store_drivers_autoprobe);
582
583static int add_probe_files(struct bus_type *bus)
584{
585 int retval;
586
587 retval = bus_create_file(bus, &bus_attr_drivers_probe);
588 if (retval)
589 goto out;
590
591 retval = bus_create_file(bus, &bus_attr_drivers_autoprobe);
592 if (retval)
593 bus_remove_file(bus, &bus_attr_drivers_probe);
594out:
595 return retval;
596}
597
598static void remove_probe_files(struct bus_type *bus)
599{
600 bus_remove_file(bus, &bus_attr_drivers_autoprobe);
601 bus_remove_file(bus, &bus_attr_drivers_probe);
602}
603#else
604static inline int add_bind_files(struct device_driver *drv) { return 0; }
605static inline void remove_bind_files(struct device_driver *drv) {}
606static inline int add_probe_files(struct bus_type *bus) { return 0; }
607static inline void remove_probe_files(struct bus_type *bus) {}
608#endif
609
610static ssize_t driver_uevent_store(struct device_driver *drv,
611 const char *buf, size_t count)
612{
613 enum kobject_action action;
614
615 if (kobject_action_type(buf, count, &action) == 0)
616 kobject_uevent(&drv->p->kobj, action);
617 return count;
618}
619static DRIVER_ATTR(uevent, S_IWUSR, NULL, driver_uevent_store);
620
621/**
622 * bus_add_driver - Add a driver to the bus.
623 * @drv: driver.
624 */
625int bus_add_driver(struct device_driver *drv)
626{
627 struct bus_type *bus;
628 struct driver_private *priv;
629 int error = 0;
630
631 bus = bus_get(drv->bus);
632 if (!bus)
633 return -EINVAL;
634
635 pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name);
636
637 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
638 if (!priv) {
639 error = -ENOMEM;
640 goto out_put_bus;
641 }
642 klist_init(&priv->klist_devices, NULL, NULL);
643 priv->driver = drv;
644 drv->p = priv;
645 priv->kobj.kset = bus->p->drivers_kset;
646 error = kobject_init_and_add(&priv->kobj, &driver_ktype, NULL,
647 "%s", drv->name);
648 if (error)
649 goto out_unregister;
650
651 if (drv->bus->p->drivers_autoprobe) {
652 error = driver_attach(drv);
653 if (error)
654 goto out_unregister;
655 }
656 klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers);
657 module_add_driver(drv->owner, drv);
658
659 error = driver_create_file(drv, &driver_attr_uevent);
660 if (error) {
661 printk(KERN_ERR "%s: uevent attr (%s) failed\n",
662 __func__, drv->name);
663 }
664 error = driver_add_attrs(bus, drv);
665 if (error) {
666 /* How the hell do we get out of this pickle? Give up */
667 printk(KERN_ERR "%s: driver_add_attrs(%s) failed\n",
668 __func__, drv->name);
669 }
670
671 if (!drv->suppress_bind_attrs) {
672 error = add_bind_files(drv);
673 if (error) {
674 /* Ditto */
675 printk(KERN_ERR "%s: add_bind_files(%s) failed\n",
676 __func__, drv->name);
677 }
678 }
679
680 kobject_uevent(&priv->kobj, KOBJ_ADD);
681 return 0;
682
683out_unregister:
684 kobject_put(&priv->kobj);
685 kfree(drv->p);
686 drv->p = NULL;
687out_put_bus:
688 bus_put(bus);
689 return error;
690}
691
692/**
693 * bus_remove_driver - delete driver from bus's knowledge.
694 * @drv: driver.
695 *
696 * Detach the driver from the devices it controls, and remove
697 * it from its bus's list of drivers. Finally, we drop the reference
698 * to the bus we took in bus_add_driver().
699 */
700void bus_remove_driver(struct device_driver *drv)
701{
702 if (!drv->bus)
703 return;
704
705 if (!drv->suppress_bind_attrs)
706 remove_bind_files(drv);
707 driver_remove_attrs(drv->bus, drv);
708 driver_remove_file(drv, &driver_attr_uevent);
709 klist_remove(&drv->p->knode_bus);
710 pr_debug("bus: '%s': remove driver %s\n", drv->bus->name, drv->name);
711 driver_detach(drv);
712 module_remove_driver(drv);
713 kobject_put(&drv->p->kobj);
714 bus_put(drv->bus);
715}
716
717/* Helper for bus_rescan_devices's iter */
718static int __must_check bus_rescan_devices_helper(struct device *dev,
719 void *data)
720{
721 int ret = 0;
722
723 if (!dev->driver) {
724 if (dev->parent) /* Needed for USB */
725 device_lock(dev->parent);
726 ret = device_attach(dev);
727 if (dev->parent)
728 device_unlock(dev->parent);
729 }
730 return ret < 0 ? ret : 0;
731}
732
733/**
734 * bus_rescan_devices - rescan devices on the bus for possible drivers
735 * @bus: the bus to scan.
736 *
737 * This function will look for devices on the bus with no driver
738 * attached and rescan it against existing drivers to see if it matches
739 * any by calling device_attach() for the unbound devices.
740 */
741int bus_rescan_devices(struct bus_type *bus)
742{
743 return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
744}
745EXPORT_SYMBOL_GPL(bus_rescan_devices);
746
747/**
748 * device_reprobe - remove driver for a device and probe for a new driver
749 * @dev: the device to reprobe
750 *
751 * This function detaches the attached driver (if any) for the given
752 * device and restarts the driver probing process. It is intended
753 * to use if probing criteria changed during a devices lifetime and
754 * driver attachment should change accordingly.
755 */
756int device_reprobe(struct device *dev)
757{
758 if (dev->driver) {
759 if (dev->parent) /* Needed for USB */
760 device_lock(dev->parent);
761 device_release_driver(dev);
762 if (dev->parent)
763 device_unlock(dev->parent);
764 }
765 return bus_rescan_devices_helper(dev, NULL);
766}
767EXPORT_SYMBOL_GPL(device_reprobe);
768
769/**
770 * find_bus - locate bus by name.
771 * @name: name of bus.
772 *
773 * Call kset_find_obj() to iterate over list of buses to
774 * find a bus by name. Return bus if found.
775 *
776 * Note that kset_find_obj increments bus' reference count.
777 */
778#if 0
779struct bus_type *find_bus(char *name)
780{
781 struct kobject *k = kset_find_obj(bus_kset, name);
782 return k ? to_bus(k) : NULL;
783}
784#endif /* 0 */
785
786
787/**
788 * bus_add_attrs - Add default attributes for this bus.
789 * @bus: Bus that has just been registered.
790 */
791
792static int bus_add_attrs(struct bus_type *bus)
793{
794 int error = 0;
795 int i;
796
797 if (bus->bus_attrs) {
798 for (i = 0; attr_name(bus->bus_attrs[i]); i++) {
799 error = bus_create_file(bus, &bus->bus_attrs[i]);
800 if (error)
801 goto err;
802 }
803 }
804done:
805 return error;
806err:
807 while (--i >= 0)
808 bus_remove_file(bus, &bus->bus_attrs[i]);
809 goto done;
810}
811
812static void bus_remove_attrs(struct bus_type *bus)
813{
814 int i;
815
816 if (bus->bus_attrs) {
817 for (i = 0; attr_name(bus->bus_attrs[i]); i++)
818 bus_remove_file(bus, &bus->bus_attrs[i]);
819 }
820}
821
822static void klist_devices_get(struct klist_node *n)
823{
824 struct device_private *dev_prv = to_device_private_bus(n);
825 struct device *dev = dev_prv->device;
826
827 get_device(dev);
828}
829
830static void klist_devices_put(struct klist_node *n)
831{
832 struct device_private *dev_prv = to_device_private_bus(n);
833 struct device *dev = dev_prv->device;
834
835 put_device(dev);
836}
837
838static ssize_t bus_uevent_store(struct bus_type *bus,
839 const char *buf, size_t count)
840{
841 enum kobject_action action;
842
843 if (kobject_action_type(buf, count, &action) == 0)
844 kobject_uevent(&bus->p->subsys.kobj, action);
845 return count;
846}
847static BUS_ATTR(uevent, S_IWUSR, NULL, bus_uevent_store);
848
849/**
850 * bus_register - register a bus with the system.
851 * @bus: bus.
852 *
853 * Once we have that, we registered the bus with the kobject
854 * infrastructure, then register the children subsystems it has:
855 * the devices and drivers that belong to the bus.
856 */
857int bus_register(struct bus_type *bus)
858{
859 int retval;
860 struct subsys_private *priv;
861
862 priv = kzalloc(sizeof(struct subsys_private), GFP_KERNEL);
863 if (!priv)
864 return -ENOMEM;
865
866 priv->bus = bus;
867 bus->p = priv;
868
869 BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier);
870
871 retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name);
872 if (retval)
873 goto out;
874
875 priv->subsys.kobj.kset = bus_kset;
876 priv->subsys.kobj.ktype = &bus_ktype;
877 priv->drivers_autoprobe = 1;
878
879 retval = kset_register(&priv->subsys);
880 if (retval)
881 goto out;
882
883 retval = bus_create_file(bus, &bus_attr_uevent);
884 if (retval)
885 goto bus_uevent_fail;
886
887 priv->devices_kset = kset_create_and_add("devices", NULL,
888 &priv->subsys.kobj);
889 if (!priv->devices_kset) {
890 retval = -ENOMEM;
891 goto bus_devices_fail;
892 }
893
894 priv->drivers_kset = kset_create_and_add("drivers", NULL,
895 &priv->subsys.kobj);
896 if (!priv->drivers_kset) {
897 retval = -ENOMEM;
898 goto bus_drivers_fail;
899 }
900
901 klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put);
902 klist_init(&priv->klist_drivers, NULL, NULL);
903
904 retval = add_probe_files(bus);
905 if (retval)
906 goto bus_probe_files_fail;
907
908 retval = bus_add_attrs(bus);
909 if (retval)
910 goto bus_attrs_fail;
911
912 pr_debug("bus: '%s': registered\n", bus->name);
913 return 0;
914
915bus_attrs_fail:
916 remove_probe_files(bus);
917bus_probe_files_fail:
918 kset_unregister(bus->p->drivers_kset);
919bus_drivers_fail:
920 kset_unregister(bus->p->devices_kset);
921bus_devices_fail:
922 bus_remove_file(bus, &bus_attr_uevent);
923bus_uevent_fail:
924 kset_unregister(&bus->p->subsys);
925out:
926 kfree(bus->p);
927 bus->p = NULL;
928 return retval;
929}
930EXPORT_SYMBOL_GPL(bus_register);
931
932/**
933 * bus_unregister - remove a bus from the system
934 * @bus: bus.
935 *
936 * Unregister the child subsystems and the bus itself.
937 * Finally, we call bus_put() to release the refcount
938 */
939void bus_unregister(struct bus_type *bus)
940{
941 pr_debug("bus: '%s': unregistering\n", bus->name);
942 bus_remove_attrs(bus);
943 remove_probe_files(bus);
944 kset_unregister(bus->p->drivers_kset);
945 kset_unregister(bus->p->devices_kset);
946 bus_remove_file(bus, &bus_attr_uevent);
947 kset_unregister(&bus->p->subsys);
948 kfree(bus->p);
949 bus->p = NULL;
950}
951EXPORT_SYMBOL_GPL(bus_unregister);
952
953int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
954{
955 return blocking_notifier_chain_register(&bus->p->bus_notifier, nb);
956}
957EXPORT_SYMBOL_GPL(bus_register_notifier);
958
959int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
960{
961 return blocking_notifier_chain_unregister(&bus->p->bus_notifier, nb);
962}
963EXPORT_SYMBOL_GPL(bus_unregister_notifier);
964
965struct kset *bus_get_kset(struct bus_type *bus)
966{
967 return &bus->p->subsys;
968}
969EXPORT_SYMBOL_GPL(bus_get_kset);
970
971struct klist *bus_get_device_klist(struct bus_type *bus)
972{
973 return &bus->p->klist_devices;
974}
975EXPORT_SYMBOL_GPL(bus_get_device_klist);
976
977/*
978 * Yes, this forcibly breaks the klist abstraction temporarily. It
979 * just wants to sort the klist, not change reference counts and
980 * take/drop locks rapidly in the process. It does all this while
981 * holding the lock for the list, so objects can't otherwise be
982 * added/removed while we're swizzling.
983 */
984static void device_insertion_sort_klist(struct device *a, struct list_head *list,
985 int (*compare)(const struct device *a,
986 const struct device *b))
987{
988 struct list_head *pos;
989 struct klist_node *n;
990 struct device_private *dev_prv;
991 struct device *b;
992
993 list_for_each(pos, list) {
994 n = container_of(pos, struct klist_node, n_node);
995 dev_prv = to_device_private_bus(n);
996 b = dev_prv->device;
997 if (compare(a, b) <= 0) {
998 list_move_tail(&a->p->knode_bus.n_node,
999 &b->p->knode_bus.n_node);
1000 return;
1001 }
1002 }
1003 list_move_tail(&a->p->knode_bus.n_node, list);
1004}
1005
1006void bus_sort_breadthfirst(struct bus_type *bus,
1007 int (*compare)(const struct device *a,
1008 const struct device *b))
1009{
1010 LIST_HEAD(sorted_devices);
1011 struct list_head *pos, *tmp;
1012 struct klist_node *n;
1013 struct device_private *dev_prv;
1014 struct device *dev;
1015 struct klist *device_klist;
1016
1017 device_klist = bus_get_device_klist(bus);
1018
1019 spin_lock(&device_klist->k_lock);
1020 list_for_each_safe(pos, tmp, &device_klist->k_list) {
1021 n = container_of(pos, struct klist_node, n_node);
1022 dev_prv = to_device_private_bus(n);
1023 dev = dev_prv->device;
1024 device_insertion_sort_klist(dev, &sorted_devices, compare);
1025 }
1026 list_splice(&sorted_devices, &device_klist->k_list);
1027 spin_unlock(&device_klist->k_lock);
1028}
1029EXPORT_SYMBOL_GPL(bus_sort_breadthfirst);
1030
1031int __init buses_init(void)
1032{
1033 bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);
1034 if (!bus_kset)
1035 return -ENOMEM;
1036 return 0;
1037}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * bus.c - bus driver management
4 *
5 * Copyright (c) 2002-3 Patrick Mochel
6 * Copyright (c) 2002-3 Open Source Development Labs
7 * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de>
8 * Copyright (c) 2007 Novell Inc.
9 */
10
11#include <linux/async.h>
12#include <linux/device/bus.h>
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>
20#include <linux/sysfs.h>
21#include "base.h"
22#include "power/power.h"
23
24/* /sys/devices/system */
25static struct kset *system_kset;
26
27#define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
28
29/*
30 * sysfs bindings for drivers
31 */
32
33#define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
34
35#define DRIVER_ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) \
36 struct driver_attribute driver_attr_##_name = \
37 __ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store)
38
39static int __must_check bus_rescan_devices_helper(struct device *dev,
40 void *data);
41
42static struct bus_type *bus_get(struct bus_type *bus)
43{
44 if (bus) {
45 kset_get(&bus->p->subsys);
46 return bus;
47 }
48 return NULL;
49}
50
51static void bus_put(struct bus_type *bus)
52{
53 if (bus)
54 kset_put(&bus->p->subsys);
55}
56
57static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr,
58 char *buf)
59{
60 struct driver_attribute *drv_attr = to_drv_attr(attr);
61 struct driver_private *drv_priv = to_driver(kobj);
62 ssize_t ret = -EIO;
63
64 if (drv_attr->show)
65 ret = drv_attr->show(drv_priv->driver, buf);
66 return ret;
67}
68
69static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr,
70 const char *buf, size_t count)
71{
72 struct driver_attribute *drv_attr = to_drv_attr(attr);
73 struct driver_private *drv_priv = to_driver(kobj);
74 ssize_t ret = -EIO;
75
76 if (drv_attr->store)
77 ret = drv_attr->store(drv_priv->driver, buf, count);
78 return ret;
79}
80
81static const struct sysfs_ops driver_sysfs_ops = {
82 .show = drv_attr_show,
83 .store = drv_attr_store,
84};
85
86static void driver_release(struct kobject *kobj)
87{
88 struct driver_private *drv_priv = to_driver(kobj);
89
90 pr_debug("driver: '%s': %s\n", kobject_name(kobj), __func__);
91 kfree(drv_priv);
92}
93
94static struct kobj_type driver_ktype = {
95 .sysfs_ops = &driver_sysfs_ops,
96 .release = driver_release,
97};
98
99/*
100 * sysfs bindings for buses
101 */
102static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr,
103 char *buf)
104{
105 struct bus_attribute *bus_attr = to_bus_attr(attr);
106 struct subsys_private *subsys_priv = to_subsys_private(kobj);
107 ssize_t ret = 0;
108
109 if (bus_attr->show)
110 ret = bus_attr->show(subsys_priv->bus, buf);
111 return ret;
112}
113
114static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr,
115 const char *buf, size_t count)
116{
117 struct bus_attribute *bus_attr = to_bus_attr(attr);
118 struct subsys_private *subsys_priv = to_subsys_private(kobj);
119 ssize_t ret = 0;
120
121 if (bus_attr->store)
122 ret = bus_attr->store(subsys_priv->bus, buf, count);
123 return ret;
124}
125
126static const struct sysfs_ops bus_sysfs_ops = {
127 .show = bus_attr_show,
128 .store = bus_attr_store,
129};
130
131int bus_create_file(struct bus_type *bus, struct bus_attribute *attr)
132{
133 int error;
134 if (bus_get(bus)) {
135 error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr);
136 bus_put(bus);
137 } else
138 error = -EINVAL;
139 return error;
140}
141EXPORT_SYMBOL_GPL(bus_create_file);
142
143void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr)
144{
145 if (bus_get(bus)) {
146 sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr);
147 bus_put(bus);
148 }
149}
150EXPORT_SYMBOL_GPL(bus_remove_file);
151
152static void bus_release(struct kobject *kobj)
153{
154 struct subsys_private *priv = to_subsys_private(kobj);
155 struct bus_type *bus = priv->bus;
156
157 kfree(priv);
158 bus->p = NULL;
159}
160
161static struct kobj_type bus_ktype = {
162 .sysfs_ops = &bus_sysfs_ops,
163 .release = bus_release,
164};
165
166static int bus_uevent_filter(const struct kobject *kobj)
167{
168 const struct kobj_type *ktype = get_ktype(kobj);
169
170 if (ktype == &bus_ktype)
171 return 1;
172 return 0;
173}
174
175static const struct kset_uevent_ops bus_uevent_ops = {
176 .filter = bus_uevent_filter,
177};
178
179static struct kset *bus_kset;
180
181/* Manually detach a device from its associated driver. */
182static ssize_t unbind_store(struct device_driver *drv, const char *buf,
183 size_t count)
184{
185 struct bus_type *bus = bus_get(drv->bus);
186 struct device *dev;
187 int err = -ENODEV;
188
189 dev = bus_find_device_by_name(bus, NULL, buf);
190 if (dev && dev->driver == drv) {
191 device_driver_detach(dev);
192 err = count;
193 }
194 put_device(dev);
195 bus_put(bus);
196 return err;
197}
198static DRIVER_ATTR_IGNORE_LOCKDEP(unbind, 0200, NULL, unbind_store);
199
200/*
201 * Manually attach a device to a driver.
202 * Note: the driver must want to bind to the device,
203 * it is not possible to override the driver's id table.
204 */
205static ssize_t bind_store(struct device_driver *drv, const char *buf,
206 size_t count)
207{
208 struct bus_type *bus = bus_get(drv->bus);
209 struct device *dev;
210 int err = -ENODEV;
211
212 dev = bus_find_device_by_name(bus, NULL, buf);
213 if (dev && driver_match_device(drv, dev)) {
214 err = device_driver_attach(drv, dev);
215 if (!err) {
216 /* success */
217 err = count;
218 }
219 }
220 put_device(dev);
221 bus_put(bus);
222 return err;
223}
224static DRIVER_ATTR_IGNORE_LOCKDEP(bind, 0200, NULL, bind_store);
225
226static ssize_t drivers_autoprobe_show(struct bus_type *bus, char *buf)
227{
228 return sysfs_emit(buf, "%d\n", bus->p->drivers_autoprobe);
229}
230
231static ssize_t drivers_autoprobe_store(struct bus_type *bus,
232 const char *buf, size_t count)
233{
234 if (buf[0] == '0')
235 bus->p->drivers_autoprobe = 0;
236 else
237 bus->p->drivers_autoprobe = 1;
238 return count;
239}
240
241static ssize_t drivers_probe_store(struct bus_type *bus,
242 const char *buf, size_t count)
243{
244 struct device *dev;
245 int err = -EINVAL;
246
247 dev = bus_find_device_by_name(bus, NULL, buf);
248 if (!dev)
249 return -ENODEV;
250 if (bus_rescan_devices_helper(dev, NULL) == 0)
251 err = count;
252 put_device(dev);
253 return err;
254}
255
256static struct device *next_device(struct klist_iter *i)
257{
258 struct klist_node *n = klist_next(i);
259 struct device *dev = NULL;
260 struct device_private *dev_prv;
261
262 if (n) {
263 dev_prv = to_device_private_bus(n);
264 dev = dev_prv->device;
265 }
266 return dev;
267}
268
269/**
270 * bus_for_each_dev - device iterator.
271 * @bus: bus type.
272 * @start: device to start iterating from.
273 * @data: data for the callback.
274 * @fn: function to be called for each device.
275 *
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.
279 *
280 * We check the return of @fn each time. If it returns anything
281 * other than 0, we break out and return that value.
282 *
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.
287 */
288int bus_for_each_dev(struct bus_type *bus, struct device *start,
289 void *data, int (*fn)(struct device *, void *))
290{
291 struct klist_iter i;
292 struct device *dev;
293 int error = 0;
294
295 if (!bus || !bus->p)
296 return -EINVAL;
297
298 klist_iter_init_node(&bus->p->klist_devices, &i,
299 (start ? &start->p->knode_bus : NULL));
300 while (!error && (dev = next_device(&i)))
301 error = fn(dev, data);
302 klist_iter_exit(&i);
303 return error;
304}
305EXPORT_SYMBOL_GPL(bus_for_each_dev);
306
307/**
308 * bus_find_device - device iterator for locating a particular device.
309 * @bus: bus type
310 * @start: Device to begin with
311 * @data: Data to pass to match function
312 * @match: Callback function to check device
313 *
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.
317 *
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.
321 */
322struct device *bus_find_device(struct bus_type *bus,
323 struct device *start, const void *data,
324 int (*match)(struct device *dev, const void *data))
325{
326 struct klist_iter i;
327 struct device *dev;
328
329 if (!bus || !bus->p)
330 return NULL;
331
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))
336 break;
337 klist_iter_exit(&i);
338 return dev;
339}
340EXPORT_SYMBOL_GPL(bus_find_device);
341
342/**
343 * subsys_find_device_by_id - find a device with a specific enumeration number
344 * @subsys: subsystem
345 * @id: index 'id' in struct device
346 * @hint: device to check first
347 *
348 * Check the hint's next object and if it is a match return it directly,
349 * otherwise, fall back to a full list search. Either way a reference for
350 * the returned object is taken.
351 */
352struct device *subsys_find_device_by_id(struct bus_type *subsys, unsigned int id,
353 struct device *hint)
354{
355 struct klist_iter i;
356 struct device *dev;
357
358 if (!subsys)
359 return NULL;
360
361 if (hint) {
362 klist_iter_init_node(&subsys->p->klist_devices, &i, &hint->p->knode_bus);
363 dev = next_device(&i);
364 if (dev && dev->id == id && get_device(dev)) {
365 klist_iter_exit(&i);
366 return dev;
367 }
368 klist_iter_exit(&i);
369 }
370
371 klist_iter_init_node(&subsys->p->klist_devices, &i, NULL);
372 while ((dev = next_device(&i))) {
373 if (dev->id == id && get_device(dev)) {
374 klist_iter_exit(&i);
375 return dev;
376 }
377 }
378 klist_iter_exit(&i);
379 return NULL;
380}
381EXPORT_SYMBOL_GPL(subsys_find_device_by_id);
382
383static struct device_driver *next_driver(struct klist_iter *i)
384{
385 struct klist_node *n = klist_next(i);
386 struct driver_private *drv_priv;
387
388 if (n) {
389 drv_priv = container_of(n, struct driver_private, knode_bus);
390 return drv_priv->driver;
391 }
392 return NULL;
393}
394
395/**
396 * bus_for_each_drv - driver iterator
397 * @bus: bus we're dealing with.
398 * @start: driver to start iterating on.
399 * @data: data to pass to the callback.
400 * @fn: function to call for each driver.
401 *
402 * This is nearly identical to the device iterator above.
403 * We iterate over each driver that belongs to @bus, and call
404 * @fn for each. If @fn returns anything but 0, we break out
405 * and return it. If @start is not NULL, we use it as the head
406 * of the list.
407 *
408 * NOTE: we don't return the driver that returns a non-zero
409 * value, nor do we leave the reference count incremented for that
410 * driver. If the caller needs to know that info, it must set it
411 * in the callback. It must also be sure to increment the refcount
412 * so it doesn't disappear before returning to the caller.
413 */
414int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
415 void *data, int (*fn)(struct device_driver *, void *))
416{
417 struct klist_iter i;
418 struct device_driver *drv;
419 int error = 0;
420
421 if (!bus)
422 return -EINVAL;
423
424 klist_iter_init_node(&bus->p->klist_drivers, &i,
425 start ? &start->p->knode_bus : NULL);
426 while ((drv = next_driver(&i)) && !error)
427 error = fn(drv, data);
428 klist_iter_exit(&i);
429 return error;
430}
431EXPORT_SYMBOL_GPL(bus_for_each_drv);
432
433/**
434 * bus_add_device - add device to bus
435 * @dev: device being added
436 *
437 * - Add device's bus attributes.
438 * - Create links to device's bus.
439 * - Add the device to its bus's list of devices.
440 */
441int bus_add_device(struct device *dev)
442{
443 struct bus_type *bus = bus_get(dev->bus);
444 int error = 0;
445
446 if (bus) {
447 pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev));
448 error = device_add_groups(dev, bus->dev_groups);
449 if (error)
450 goto out_put;
451 error = sysfs_create_link(&bus->p->devices_kset->kobj,
452 &dev->kobj, dev_name(dev));
453 if (error)
454 goto out_groups;
455 error = sysfs_create_link(&dev->kobj,
456 &dev->bus->p->subsys.kobj, "subsystem");
457 if (error)
458 goto out_subsys;
459 klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices);
460 }
461 return 0;
462
463out_subsys:
464 sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev));
465out_groups:
466 device_remove_groups(dev, bus->dev_groups);
467out_put:
468 bus_put(dev->bus);
469 return error;
470}
471
472/**
473 * bus_probe_device - probe drivers for a new device
474 * @dev: device to probe
475 *
476 * - Automatically probe for a driver if the bus allows it.
477 */
478void bus_probe_device(struct device *dev)
479{
480 struct bus_type *bus = dev->bus;
481 struct subsys_interface *sif;
482
483 if (!bus)
484 return;
485
486 if (bus->p->drivers_autoprobe)
487 device_initial_probe(dev);
488
489 mutex_lock(&bus->p->mutex);
490 list_for_each_entry(sif, &bus->p->interfaces, node)
491 if (sif->add_dev)
492 sif->add_dev(dev, sif);
493 mutex_unlock(&bus->p->mutex);
494}
495
496/**
497 * bus_remove_device - remove device from bus
498 * @dev: device to be removed
499 *
500 * - Remove device from all interfaces.
501 * - Remove symlink from bus' directory.
502 * - Delete device from bus's list.
503 * - Detach from its driver.
504 * - Drop reference taken in bus_add_device().
505 */
506void bus_remove_device(struct device *dev)
507{
508 struct bus_type *bus = dev->bus;
509 struct subsys_interface *sif;
510
511 if (!bus)
512 return;
513
514 mutex_lock(&bus->p->mutex);
515 list_for_each_entry(sif, &bus->p->interfaces, node)
516 if (sif->remove_dev)
517 sif->remove_dev(dev, sif);
518 mutex_unlock(&bus->p->mutex);
519
520 sysfs_remove_link(&dev->kobj, "subsystem");
521 sysfs_remove_link(&dev->bus->p->devices_kset->kobj,
522 dev_name(dev));
523 device_remove_groups(dev, dev->bus->dev_groups);
524 if (klist_node_attached(&dev->p->knode_bus))
525 klist_del(&dev->p->knode_bus);
526
527 pr_debug("bus: '%s': remove device %s\n",
528 dev->bus->name, dev_name(dev));
529 device_release_driver(dev);
530 bus_put(dev->bus);
531}
532
533static int __must_check add_bind_files(struct device_driver *drv)
534{
535 int ret;
536
537 ret = driver_create_file(drv, &driver_attr_unbind);
538 if (ret == 0) {
539 ret = driver_create_file(drv, &driver_attr_bind);
540 if (ret)
541 driver_remove_file(drv, &driver_attr_unbind);
542 }
543 return ret;
544}
545
546static void remove_bind_files(struct device_driver *drv)
547{
548 driver_remove_file(drv, &driver_attr_bind);
549 driver_remove_file(drv, &driver_attr_unbind);
550}
551
552static BUS_ATTR_WO(drivers_probe);
553static BUS_ATTR_RW(drivers_autoprobe);
554
555static int add_probe_files(struct bus_type *bus)
556{
557 int retval;
558
559 retval = bus_create_file(bus, &bus_attr_drivers_probe);
560 if (retval)
561 goto out;
562
563 retval = bus_create_file(bus, &bus_attr_drivers_autoprobe);
564 if (retval)
565 bus_remove_file(bus, &bus_attr_drivers_probe);
566out:
567 return retval;
568}
569
570static void remove_probe_files(struct bus_type *bus)
571{
572 bus_remove_file(bus, &bus_attr_drivers_autoprobe);
573 bus_remove_file(bus, &bus_attr_drivers_probe);
574}
575
576static ssize_t uevent_store(struct device_driver *drv, const char *buf,
577 size_t count)
578{
579 int rc;
580
581 rc = kobject_synth_uevent(&drv->p->kobj, buf, count);
582 return rc ? rc : count;
583}
584static DRIVER_ATTR_WO(uevent);
585
586/**
587 * bus_add_driver - Add a driver to the bus.
588 * @drv: driver.
589 */
590int bus_add_driver(struct device_driver *drv)
591{
592 struct bus_type *bus;
593 struct driver_private *priv;
594 int error = 0;
595
596 bus = bus_get(drv->bus);
597 if (!bus)
598 return -EINVAL;
599
600 pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name);
601
602 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
603 if (!priv) {
604 error = -ENOMEM;
605 goto out_put_bus;
606 }
607 klist_init(&priv->klist_devices, NULL, NULL);
608 priv->driver = drv;
609 drv->p = priv;
610 priv->kobj.kset = bus->p->drivers_kset;
611 error = kobject_init_and_add(&priv->kobj, &driver_ktype, NULL,
612 "%s", drv->name);
613 if (error)
614 goto out_unregister;
615
616 klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers);
617 if (drv->bus->p->drivers_autoprobe) {
618 error = driver_attach(drv);
619 if (error)
620 goto out_del_list;
621 }
622 module_add_driver(drv->owner, drv);
623
624 error = driver_create_file(drv, &driver_attr_uevent);
625 if (error) {
626 printk(KERN_ERR "%s: uevent attr (%s) failed\n",
627 __func__, drv->name);
628 }
629 error = driver_add_groups(drv, bus->drv_groups);
630 if (error) {
631 /* How the hell do we get out of this pickle? Give up */
632 printk(KERN_ERR "%s: driver_add_groups(%s) failed\n",
633 __func__, drv->name);
634 }
635
636 if (!drv->suppress_bind_attrs) {
637 error = add_bind_files(drv);
638 if (error) {
639 /* Ditto */
640 printk(KERN_ERR "%s: add_bind_files(%s) failed\n",
641 __func__, drv->name);
642 }
643 }
644
645 return 0;
646
647out_del_list:
648 klist_del(&priv->knode_bus);
649out_unregister:
650 kobject_put(&priv->kobj);
651 /* drv->p is freed in driver_release() */
652 drv->p = NULL;
653out_put_bus:
654 bus_put(bus);
655 return error;
656}
657
658/**
659 * bus_remove_driver - delete driver from bus's knowledge.
660 * @drv: driver.
661 *
662 * Detach the driver from the devices it controls, and remove
663 * it from its bus's list of drivers. Finally, we drop the reference
664 * to the bus we took in bus_add_driver().
665 */
666void bus_remove_driver(struct device_driver *drv)
667{
668 if (!drv->bus)
669 return;
670
671 if (!drv->suppress_bind_attrs)
672 remove_bind_files(drv);
673 driver_remove_groups(drv, drv->bus->drv_groups);
674 driver_remove_file(drv, &driver_attr_uevent);
675 klist_remove(&drv->p->knode_bus);
676 pr_debug("bus: '%s': remove driver %s\n", drv->bus->name, drv->name);
677 driver_detach(drv);
678 module_remove_driver(drv);
679 kobject_put(&drv->p->kobj);
680 bus_put(drv->bus);
681}
682
683/* Helper for bus_rescan_devices's iter */
684static int __must_check bus_rescan_devices_helper(struct device *dev,
685 void *data)
686{
687 int ret = 0;
688
689 if (!dev->driver) {
690 if (dev->parent && dev->bus->need_parent_lock)
691 device_lock(dev->parent);
692 ret = device_attach(dev);
693 if (dev->parent && dev->bus->need_parent_lock)
694 device_unlock(dev->parent);
695 }
696 return ret < 0 ? ret : 0;
697}
698
699/**
700 * bus_rescan_devices - rescan devices on the bus for possible drivers
701 * @bus: the bus to scan.
702 *
703 * This function will look for devices on the bus with no driver
704 * attached and rescan it against existing drivers to see if it matches
705 * any by calling device_attach() for the unbound devices.
706 */
707int bus_rescan_devices(struct bus_type *bus)
708{
709 return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
710}
711EXPORT_SYMBOL_GPL(bus_rescan_devices);
712
713/**
714 * device_reprobe - remove driver for a device and probe for a new driver
715 * @dev: the device to reprobe
716 *
717 * This function detaches the attached driver (if any) for the given
718 * device and restarts the driver probing process. It is intended
719 * to use if probing criteria changed during a devices lifetime and
720 * driver attachment should change accordingly.
721 */
722int device_reprobe(struct device *dev)
723{
724 if (dev->driver)
725 device_driver_detach(dev);
726 return bus_rescan_devices_helper(dev, NULL);
727}
728EXPORT_SYMBOL_GPL(device_reprobe);
729
730static int bus_add_groups(struct bus_type *bus,
731 const struct attribute_group **groups)
732{
733 return sysfs_create_groups(&bus->p->subsys.kobj, groups);
734}
735
736static void bus_remove_groups(struct bus_type *bus,
737 const struct attribute_group **groups)
738{
739 sysfs_remove_groups(&bus->p->subsys.kobj, groups);
740}
741
742static void klist_devices_get(struct klist_node *n)
743{
744 struct device_private *dev_prv = to_device_private_bus(n);
745 struct device *dev = dev_prv->device;
746
747 get_device(dev);
748}
749
750static void klist_devices_put(struct klist_node *n)
751{
752 struct device_private *dev_prv = to_device_private_bus(n);
753 struct device *dev = dev_prv->device;
754
755 put_device(dev);
756}
757
758static ssize_t bus_uevent_store(struct bus_type *bus,
759 const char *buf, size_t count)
760{
761 int rc;
762
763 rc = kobject_synth_uevent(&bus->p->subsys.kobj, buf, count);
764 return rc ? rc : count;
765}
766/*
767 * "open code" the old BUS_ATTR() macro here. We want to use BUS_ATTR_WO()
768 * here, but can not use it as earlier in the file we have
769 * DEVICE_ATTR_WO(uevent), which would cause a clash with the with the store
770 * function name.
771 */
772static struct bus_attribute bus_attr_uevent = __ATTR(uevent, 0200, NULL,
773 bus_uevent_store);
774
775/**
776 * bus_register - register a driver-core subsystem
777 * @bus: bus to register
778 *
779 * Once we have that, we register the bus with the kobject
780 * infrastructure, then register the children subsystems it has:
781 * the devices and drivers that belong to the subsystem.
782 */
783int bus_register(struct bus_type *bus)
784{
785 int retval;
786 struct subsys_private *priv;
787 struct lock_class_key *key = &bus->lock_key;
788
789 priv = kzalloc(sizeof(struct subsys_private), GFP_KERNEL);
790 if (!priv)
791 return -ENOMEM;
792
793 priv->bus = bus;
794 bus->p = priv;
795
796 BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier);
797
798 retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name);
799 if (retval)
800 goto out;
801
802 priv->subsys.kobj.kset = bus_kset;
803 priv->subsys.kobj.ktype = &bus_ktype;
804 priv->drivers_autoprobe = 1;
805
806 retval = kset_register(&priv->subsys);
807 if (retval)
808 goto out;
809
810 retval = bus_create_file(bus, &bus_attr_uevent);
811 if (retval)
812 goto bus_uevent_fail;
813
814 priv->devices_kset = kset_create_and_add("devices", NULL,
815 &priv->subsys.kobj);
816 if (!priv->devices_kset) {
817 retval = -ENOMEM;
818 goto bus_devices_fail;
819 }
820
821 priv->drivers_kset = kset_create_and_add("drivers", NULL,
822 &priv->subsys.kobj);
823 if (!priv->drivers_kset) {
824 retval = -ENOMEM;
825 goto bus_drivers_fail;
826 }
827
828 INIT_LIST_HEAD(&priv->interfaces);
829 __mutex_init(&priv->mutex, "subsys mutex", key);
830 klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put);
831 klist_init(&priv->klist_drivers, NULL, NULL);
832
833 retval = add_probe_files(bus);
834 if (retval)
835 goto bus_probe_files_fail;
836
837 retval = bus_add_groups(bus, bus->bus_groups);
838 if (retval)
839 goto bus_groups_fail;
840
841 pr_debug("bus: '%s': registered\n", bus->name);
842 return 0;
843
844bus_groups_fail:
845 remove_probe_files(bus);
846bus_probe_files_fail:
847 kset_unregister(bus->p->drivers_kset);
848bus_drivers_fail:
849 kset_unregister(bus->p->devices_kset);
850bus_devices_fail:
851 bus_remove_file(bus, &bus_attr_uevent);
852bus_uevent_fail:
853 kset_unregister(&bus->p->subsys);
854out:
855 kfree(bus->p);
856 bus->p = NULL;
857 return retval;
858}
859EXPORT_SYMBOL_GPL(bus_register);
860
861/**
862 * bus_unregister - remove a bus from the system
863 * @bus: bus.
864 *
865 * Unregister the child subsystems and the bus itself.
866 * Finally, we call bus_put() to release the refcount
867 */
868void bus_unregister(struct bus_type *bus)
869{
870 pr_debug("bus: '%s': unregistering\n", bus->name);
871 if (bus->dev_root)
872 device_unregister(bus->dev_root);
873 bus_remove_groups(bus, bus->bus_groups);
874 remove_probe_files(bus);
875 kset_unregister(bus->p->drivers_kset);
876 kset_unregister(bus->p->devices_kset);
877 bus_remove_file(bus, &bus_attr_uevent);
878 kset_unregister(&bus->p->subsys);
879}
880EXPORT_SYMBOL_GPL(bus_unregister);
881
882int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
883{
884 return blocking_notifier_chain_register(&bus->p->bus_notifier, nb);
885}
886EXPORT_SYMBOL_GPL(bus_register_notifier);
887
888int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
889{
890 return blocking_notifier_chain_unregister(&bus->p->bus_notifier, nb);
891}
892EXPORT_SYMBOL_GPL(bus_unregister_notifier);
893
894struct kset *bus_get_kset(struct bus_type *bus)
895{
896 return &bus->p->subsys;
897}
898EXPORT_SYMBOL_GPL(bus_get_kset);
899
900struct klist *bus_get_device_klist(struct bus_type *bus)
901{
902 return &bus->p->klist_devices;
903}
904EXPORT_SYMBOL_GPL(bus_get_device_klist);
905
906/*
907 * Yes, this forcibly breaks the klist abstraction temporarily. It
908 * just wants to sort the klist, not change reference counts and
909 * take/drop locks rapidly in the process. It does all this while
910 * holding the lock for the list, so objects can't otherwise be
911 * added/removed while we're swizzling.
912 */
913static void device_insertion_sort_klist(struct device *a, struct list_head *list,
914 int (*compare)(const struct device *a,
915 const struct device *b))
916{
917 struct klist_node *n;
918 struct device_private *dev_prv;
919 struct device *b;
920
921 list_for_each_entry(n, list, n_node) {
922 dev_prv = to_device_private_bus(n);
923 b = dev_prv->device;
924 if (compare(a, b) <= 0) {
925 list_move_tail(&a->p->knode_bus.n_node,
926 &b->p->knode_bus.n_node);
927 return;
928 }
929 }
930 list_move_tail(&a->p->knode_bus.n_node, list);
931}
932
933void bus_sort_breadthfirst(struct bus_type *bus,
934 int (*compare)(const struct device *a,
935 const struct device *b))
936{
937 LIST_HEAD(sorted_devices);
938 struct klist_node *n, *tmp;
939 struct device_private *dev_prv;
940 struct device *dev;
941 struct klist *device_klist;
942
943 device_klist = bus_get_device_klist(bus);
944
945 spin_lock(&device_klist->k_lock);
946 list_for_each_entry_safe(n, tmp, &device_klist->k_list, n_node) {
947 dev_prv = to_device_private_bus(n);
948 dev = dev_prv->device;
949 device_insertion_sort_klist(dev, &sorted_devices, compare);
950 }
951 list_splice(&sorted_devices, &device_klist->k_list);
952 spin_unlock(&device_klist->k_lock);
953}
954EXPORT_SYMBOL_GPL(bus_sort_breadthfirst);
955
956/**
957 * subsys_dev_iter_init - initialize subsys device iterator
958 * @iter: subsys iterator to initialize
959 * @subsys: the subsys we wanna iterate over
960 * @start: the device to start iterating from, if any
961 * @type: device_type of the devices to iterate over, NULL for all
962 *
963 * Initialize subsys iterator @iter such that it iterates over devices
964 * of @subsys. If @start is set, the list iteration will start there,
965 * otherwise if it is NULL, the iteration starts at the beginning of
966 * the list.
967 */
968void subsys_dev_iter_init(struct subsys_dev_iter *iter, struct bus_type *subsys,
969 struct device *start, const struct device_type *type)
970{
971 struct klist_node *start_knode = NULL;
972
973 if (start)
974 start_knode = &start->p->knode_bus;
975 klist_iter_init_node(&subsys->p->klist_devices, &iter->ki, start_knode);
976 iter->type = type;
977}
978EXPORT_SYMBOL_GPL(subsys_dev_iter_init);
979
980/**
981 * subsys_dev_iter_next - iterate to the next device
982 * @iter: subsys iterator to proceed
983 *
984 * Proceed @iter to the next device and return it. Returns NULL if
985 * iteration is complete.
986 *
987 * The returned device is referenced and won't be released till
988 * iterator is proceed to the next device or exited. The caller is
989 * free to do whatever it wants to do with the device including
990 * calling back into subsys code.
991 */
992struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter)
993{
994 struct klist_node *knode;
995 struct device *dev;
996
997 for (;;) {
998 knode = klist_next(&iter->ki);
999 if (!knode)
1000 return NULL;
1001 dev = to_device_private_bus(knode)->device;
1002 if (!iter->type || iter->type == dev->type)
1003 return dev;
1004 }
1005}
1006EXPORT_SYMBOL_GPL(subsys_dev_iter_next);
1007
1008/**
1009 * subsys_dev_iter_exit - finish iteration
1010 * @iter: subsys iterator to finish
1011 *
1012 * Finish an iteration. Always call this function after iteration is
1013 * complete whether the iteration ran till the end or not.
1014 */
1015void subsys_dev_iter_exit(struct subsys_dev_iter *iter)
1016{
1017 klist_iter_exit(&iter->ki);
1018}
1019EXPORT_SYMBOL_GPL(subsys_dev_iter_exit);
1020
1021int subsys_interface_register(struct subsys_interface *sif)
1022{
1023 struct bus_type *subsys;
1024 struct subsys_dev_iter iter;
1025 struct device *dev;
1026
1027 if (!sif || !sif->subsys)
1028 return -ENODEV;
1029
1030 subsys = bus_get(sif->subsys);
1031 if (!subsys)
1032 return -EINVAL;
1033
1034 mutex_lock(&subsys->p->mutex);
1035 list_add_tail(&sif->node, &subsys->p->interfaces);
1036 if (sif->add_dev) {
1037 subsys_dev_iter_init(&iter, subsys, NULL, NULL);
1038 while ((dev = subsys_dev_iter_next(&iter)))
1039 sif->add_dev(dev, sif);
1040 subsys_dev_iter_exit(&iter);
1041 }
1042 mutex_unlock(&subsys->p->mutex);
1043
1044 return 0;
1045}
1046EXPORT_SYMBOL_GPL(subsys_interface_register);
1047
1048void subsys_interface_unregister(struct subsys_interface *sif)
1049{
1050 struct bus_type *subsys;
1051 struct subsys_dev_iter iter;
1052 struct device *dev;
1053
1054 if (!sif || !sif->subsys)
1055 return;
1056
1057 subsys = sif->subsys;
1058
1059 mutex_lock(&subsys->p->mutex);
1060 list_del_init(&sif->node);
1061 if (sif->remove_dev) {
1062 subsys_dev_iter_init(&iter, subsys, NULL, NULL);
1063 while ((dev = subsys_dev_iter_next(&iter)))
1064 sif->remove_dev(dev, sif);
1065 subsys_dev_iter_exit(&iter);
1066 }
1067 mutex_unlock(&subsys->p->mutex);
1068
1069 bus_put(subsys);
1070}
1071EXPORT_SYMBOL_GPL(subsys_interface_unregister);
1072
1073static void system_root_device_release(struct device *dev)
1074{
1075 kfree(dev);
1076}
1077
1078static int subsys_register(struct bus_type *subsys,
1079 const struct attribute_group **groups,
1080 struct kobject *parent_of_root)
1081{
1082 struct device *dev;
1083 int err;
1084
1085 err = bus_register(subsys);
1086 if (err < 0)
1087 return err;
1088
1089 dev = kzalloc(sizeof(struct device), GFP_KERNEL);
1090 if (!dev) {
1091 err = -ENOMEM;
1092 goto err_dev;
1093 }
1094
1095 err = dev_set_name(dev, "%s", subsys->name);
1096 if (err < 0)
1097 goto err_name;
1098
1099 dev->kobj.parent = parent_of_root;
1100 dev->groups = groups;
1101 dev->release = system_root_device_release;
1102
1103 err = device_register(dev);
1104 if (err < 0)
1105 goto err_dev_reg;
1106
1107 subsys->dev_root = dev;
1108 return 0;
1109
1110err_dev_reg:
1111 put_device(dev);
1112 dev = NULL;
1113err_name:
1114 kfree(dev);
1115err_dev:
1116 bus_unregister(subsys);
1117 return err;
1118}
1119
1120/**
1121 * subsys_system_register - register a subsystem at /sys/devices/system/
1122 * @subsys: system subsystem
1123 * @groups: default attributes for the root device
1124 *
1125 * All 'system' subsystems have a /sys/devices/system/<name> root device
1126 * with the name of the subsystem. The root device can carry subsystem-
1127 * wide attributes. All registered devices are below this single root
1128 * device and are named after the subsystem with a simple enumeration
1129 * number appended. The registered devices are not explicitly named;
1130 * only 'id' in the device needs to be set.
1131 *
1132 * Do not use this interface for anything new, it exists for compatibility
1133 * with bad ideas only. New subsystems should use plain subsystems; and
1134 * add the subsystem-wide attributes should be added to the subsystem
1135 * directory itself and not some create fake root-device placed in
1136 * /sys/devices/system/<name>.
1137 */
1138int subsys_system_register(struct bus_type *subsys,
1139 const struct attribute_group **groups)
1140{
1141 return subsys_register(subsys, groups, &system_kset->kobj);
1142}
1143EXPORT_SYMBOL_GPL(subsys_system_register);
1144
1145/**
1146 * subsys_virtual_register - register a subsystem at /sys/devices/virtual/
1147 * @subsys: virtual subsystem
1148 * @groups: default attributes for the root device
1149 *
1150 * All 'virtual' subsystems have a /sys/devices/system/<name> root device
1151 * with the name of the subystem. The root device can carry subsystem-wide
1152 * attributes. All registered devices are below this single root device.
1153 * There's no restriction on device naming. This is for kernel software
1154 * constructs which need sysfs interface.
1155 */
1156int subsys_virtual_register(struct bus_type *subsys,
1157 const struct attribute_group **groups)
1158{
1159 struct kobject *virtual_dir;
1160
1161 virtual_dir = virtual_device_parent(NULL);
1162 if (!virtual_dir)
1163 return -ENOMEM;
1164
1165 return subsys_register(subsys, groups, virtual_dir);
1166}
1167EXPORT_SYMBOL_GPL(subsys_virtual_register);
1168
1169int __init buses_init(void)
1170{
1171 bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);
1172 if (!bus_kset)
1173 return -ENOMEM;
1174
1175 system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj);
1176 if (!system_kset)
1177 return -ENOMEM;
1178
1179 return 0;
1180}