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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/*
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 <linux/mutex.h>
20#include "base.h"
21#include "power/power.h"
22
23/* /sys/devices/system */
24static struct kset *system_kset;
25
26#define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
27
28/*
29 * sysfs bindings for drivers
30 */
31
32#define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
33
34
35static int __must_check bus_rescan_devices_helper(struct device *dev,
36 void *data);
37
38static struct bus_type *bus_get(struct bus_type *bus)
39{
40 if (bus) {
41 kset_get(&bus->p->subsys);
42 return bus;
43 }
44 return NULL;
45}
46
47static void bus_put(struct bus_type *bus)
48{
49 if (bus)
50 kset_put(&bus->p->subsys);
51}
52
53static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr,
54 char *buf)
55{
56 struct driver_attribute *drv_attr = to_drv_attr(attr);
57 struct driver_private *drv_priv = to_driver(kobj);
58 ssize_t ret = -EIO;
59
60 if (drv_attr->show)
61 ret = drv_attr->show(drv_priv->driver, buf);
62 return ret;
63}
64
65static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr,
66 const char *buf, size_t count)
67{
68 struct driver_attribute *drv_attr = to_drv_attr(attr);
69 struct driver_private *drv_priv = to_driver(kobj);
70 ssize_t ret = -EIO;
71
72 if (drv_attr->store)
73 ret = drv_attr->store(drv_priv->driver, buf, count);
74 return ret;
75}
76
77static const struct sysfs_ops driver_sysfs_ops = {
78 .show = drv_attr_show,
79 .store = drv_attr_store,
80};
81
82static void driver_release(struct kobject *kobj)
83{
84 struct driver_private *drv_priv = to_driver(kobj);
85
86 pr_debug("driver: '%s': %s\n", kobject_name(kobj), __func__);
87 kfree(drv_priv);
88}
89
90static struct kobj_type driver_ktype = {
91 .sysfs_ops = &driver_sysfs_ops,
92 .release = driver_release,
93};
94
95/*
96 * sysfs bindings for buses
97 */
98static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr,
99 char *buf)
100{
101 struct bus_attribute *bus_attr = to_bus_attr(attr);
102 struct subsys_private *subsys_priv = to_subsys_private(kobj);
103 ssize_t ret = 0;
104
105 if (bus_attr->show)
106 ret = bus_attr->show(subsys_priv->bus, buf);
107 return ret;
108}
109
110static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr,
111 const char *buf, size_t count)
112{
113 struct bus_attribute *bus_attr = to_bus_attr(attr);
114 struct subsys_private *subsys_priv = to_subsys_private(kobj);
115 ssize_t ret = 0;
116
117 if (bus_attr->store)
118 ret = bus_attr->store(subsys_priv->bus, buf, count);
119 return ret;
120}
121
122static const struct sysfs_ops bus_sysfs_ops = {
123 .show = bus_attr_show,
124 .store = bus_attr_store,
125};
126
127int bus_create_file(struct bus_type *bus, struct bus_attribute *attr)
128{
129 int error;
130 if (bus_get(bus)) {
131 error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr);
132 bus_put(bus);
133 } else
134 error = -EINVAL;
135 return error;
136}
137EXPORT_SYMBOL_GPL(bus_create_file);
138
139void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr)
140{
141 if (bus_get(bus)) {
142 sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr);
143 bus_put(bus);
144 }
145}
146EXPORT_SYMBOL_GPL(bus_remove_file);
147
148static struct kobj_type bus_ktype = {
149 .sysfs_ops = &bus_sysfs_ops,
150};
151
152static int bus_uevent_filter(struct kset *kset, struct kobject *kobj)
153{
154 struct kobj_type *ktype = get_ktype(kobj);
155
156 if (ktype == &bus_ktype)
157 return 1;
158 return 0;
159}
160
161static const struct kset_uevent_ops bus_uevent_ops = {
162 .filter = bus_uevent_filter,
163};
164
165static struct kset *bus_kset;
166
167
168#ifdef CONFIG_HOTPLUG
169/* Manually detach a device from its associated driver. */
170static ssize_t driver_unbind(struct device_driver *drv,
171 const char *buf, size_t count)
172{
173 struct bus_type *bus = bus_get(drv->bus);
174 struct device *dev;
175 int err = -ENODEV;
176
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);
182 if (dev->parent)
183 device_unlock(dev->parent);
184 err = count;
185 }
186 put_device(dev);
187 bus_put(bus);
188 return err;
189}
190static DRIVER_ATTR(unbind, S_IWUSR, NULL, driver_unbind);
191
192/*
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.
196 */
197static ssize_t driver_bind(struct device_driver *drv,
198 const char *buf, size_t count)
199{
200 struct bus_type *bus = bus_get(drv->bus);
201 struct device *dev;
202 int err = -ENODEV;
203
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);
208 device_lock(dev);
209 err = driver_probe_device(drv, dev);
210 device_unlock(dev);
211 if (dev->parent)
212 device_unlock(dev->parent);
213
214 if (err > 0) {
215 /* success */
216 err = count;
217 } else if (err == 0) {
218 /* driver didn't accept device */
219 err = -ENODEV;
220 }
221 }
222 put_device(dev);
223 bus_put(bus);
224 return err;
225}
226static DRIVER_ATTR(bind, S_IWUSR, NULL, driver_bind);
227
228static ssize_t show_drivers_autoprobe(struct bus_type *bus, char *buf)
229{
230 return sprintf(buf, "%d\n", bus->p->drivers_autoprobe);
231}
232
233static ssize_t store_drivers_autoprobe(struct bus_type *bus,
234 const char *buf, size_t count)
235{
236 if (buf[0] == '0')
237 bus->p->drivers_autoprobe = 0;
238 else
239 bus->p->drivers_autoprobe = 1;
240 return count;
241}
242
243static ssize_t store_drivers_probe(struct bus_type *bus,
244 const char *buf, size_t count)
245{
246 struct device *dev;
247
248 dev = bus_find_device_by_name(bus, NULL, buf);
249 if (!dev)
250 return -ENODEV;
251 if (bus_rescan_devices_helper(dev, NULL) != 0)
252 return -EINVAL;
253 return count;
254}
255#endif
256
257static struct device *next_device(struct klist_iter *i)
258{
259 struct klist_node *n = klist_next(i);
260 struct device *dev = NULL;
261 struct device_private *dev_prv;
262
263 if (n) {
264 dev_prv = to_device_private_bus(n);
265 dev = dev_prv->device;
266 }
267 return dev;
268}
269
270/**
271 * bus_for_each_dev - device iterator.
272 * @bus: bus type.
273 * @start: device to start iterating from.
274 * @data: data for the callback.
275 * @fn: function to be called for each device.
276 *
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.
280 *
281 * We check the return of @fn each time. If it returns anything
282 * other than 0, we break out and return that value.
283 *
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.
288 */
289int bus_for_each_dev(struct bus_type *bus, struct device *start,
290 void *data, int (*fn)(struct device *, void *))
291{
292 struct klist_iter i;
293 struct device *dev;
294 int error = 0;
295
296 if (!bus)
297 return -EINVAL;
298
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);
303 klist_iter_exit(&i);
304 return error;
305}
306EXPORT_SYMBOL_GPL(bus_for_each_dev);
307
308/**
309 * bus_find_device - device iterator for locating a particular device.
310 * @bus: bus type
311 * @start: Device to begin with
312 * @data: Data to pass to match function
313 * @match: Callback function to check device
314 *
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.
318 *
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.
322 */
323struct device *bus_find_device(struct bus_type *bus,
324 struct device *start, void *data,
325 int (*match)(struct device *dev, void *data))
326{
327 struct klist_iter i;
328 struct device *dev;
329
330 if (!bus)
331 return NULL;
332
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))
337 break;
338 klist_iter_exit(&i);
339 return dev;
340}
341EXPORT_SYMBOL_GPL(bus_find_device);
342
343static int match_name(struct device *dev, void *data)
344{
345 const char *name = data;
346
347 return sysfs_streq(name, dev_name(dev));
348}
349
350/**
351 * bus_find_device_by_name - device iterator for locating a particular device of a specific name
352 * @bus: bus type
353 * @start: Device to begin with
354 * @name: name of the device to match
355 *
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
358 * function.
359 */
360struct device *bus_find_device_by_name(struct bus_type *bus,
361 struct device *start, const char *name)
362{
363 return bus_find_device(bus, start, (void *)name, match_name);
364}
365EXPORT_SYMBOL_GPL(bus_find_device_by_name);
366
367/**
368 * subsys_find_device_by_id - find a device with a specific enumeration number
369 * @subsys: subsystem
370 * @id: index 'id' in struct device
371 * @hint: device to check first
372 *
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.
376 */
377struct device *subsys_find_device_by_id(struct bus_type *subsys, unsigned int id,
378 struct device *hint)
379{
380 struct klist_iter i;
381 struct device *dev;
382
383 if (!subsys)
384 return NULL;
385
386 if (hint) {
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)) {
390 klist_iter_exit(&i);
391 return dev;
392 }
393 klist_iter_exit(&i);
394 }
395
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)) {
399 klist_iter_exit(&i);
400 return dev;
401 }
402 }
403 klist_iter_exit(&i);
404 return NULL;
405}
406EXPORT_SYMBOL_GPL(subsys_find_device_by_id);
407
408static struct device_driver *next_driver(struct klist_iter *i)
409{
410 struct klist_node *n = klist_next(i);
411 struct driver_private *drv_priv;
412
413 if (n) {
414 drv_priv = container_of(n, struct driver_private, knode_bus);
415 return drv_priv->driver;
416 }
417 return NULL;
418}
419
420/**
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.
426 *
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
431 * of the list.
432 *
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.
438 */
439int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
440 void *data, int (*fn)(struct device_driver *, void *))
441{
442 struct klist_iter i;
443 struct device_driver *drv;
444 int error = 0;
445
446 if (!bus)
447 return -EINVAL;
448
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);
453 klist_iter_exit(&i);
454 return error;
455}
456EXPORT_SYMBOL_GPL(bus_for_each_drv);
457
458static int device_add_attrs(struct bus_type *bus, struct device *dev)
459{
460 int error = 0;
461 int i;
462
463 if (!bus->dev_attrs)
464 return 0;
465
466 for (i = 0; attr_name(bus->dev_attrs[i]); i++) {
467 error = device_create_file(dev, &bus->dev_attrs[i]);
468 if (error) {
469 while (--i >= 0)
470 device_remove_file(dev, &bus->dev_attrs[i]);
471 break;
472 }
473 }
474 return error;
475}
476
477static void device_remove_attrs(struct bus_type *bus, struct device *dev)
478{
479 int i;
480
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]);
484 }
485}
486
487/**
488 * bus_add_device - add device to bus
489 * @dev: device being added
490 *
491 * - Add device's bus attributes.
492 * - Create links to device's bus.
493 * - Add the device to its bus's list of devices.
494 */
495int bus_add_device(struct device *dev)
496{
497 struct bus_type *bus = bus_get(dev->bus);
498 int error = 0;
499
500 if (bus) {
501 pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev));
502 error = device_add_attrs(bus, dev);
503 if (error)
504 goto out_put;
505 error = sysfs_create_link(&bus->p->devices_kset->kobj,
506 &dev->kobj, dev_name(dev));
507 if (error)
508 goto out_id;
509 error = sysfs_create_link(&dev->kobj,
510 &dev->bus->p->subsys.kobj, "subsystem");
511 if (error)
512 goto out_subsys;
513 klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices);
514 }
515 return 0;
516
517out_subsys:
518 sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev));
519out_id:
520 device_remove_attrs(bus, dev);
521out_put:
522 bus_put(dev->bus);
523 return error;
524}
525
526/**
527 * bus_probe_device - probe drivers for a new device
528 * @dev: device to probe
529 *
530 * - Automatically probe for a driver if the bus allows it.
531 */
532void bus_probe_device(struct device *dev)
533{
534 struct bus_type *bus = dev->bus;
535 struct subsys_interface *sif;
536 int ret;
537
538 if (!bus)
539 return;
540
541 if (bus->p->drivers_autoprobe) {
542 ret = device_attach(dev);
543 WARN_ON(ret < 0);
544 }
545
546 mutex_lock(&bus->p->mutex);
547 list_for_each_entry(sif, &bus->p->interfaces, node)
548 if (sif->add_dev)
549 sif->add_dev(dev, sif);
550 mutex_unlock(&bus->p->mutex);
551}
552
553/**
554 * bus_remove_device - remove device from bus
555 * @dev: device to be removed
556 *
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().
562 */
563void bus_remove_device(struct device *dev)
564{
565 struct bus_type *bus = dev->bus;
566 struct subsys_interface *sif;
567
568 if (!bus)
569 return;
570
571 mutex_lock(&bus->p->mutex);
572 list_for_each_entry(sif, &bus->p->interfaces, node)
573 if (sif->remove_dev)
574 sif->remove_dev(dev, sif);
575 mutex_unlock(&bus->p->mutex);
576
577 sysfs_remove_link(&dev->kobj, "subsystem");
578 sysfs_remove_link(&dev->bus->p->devices_kset->kobj,
579 dev_name(dev));
580 device_remove_attrs(dev->bus, dev);
581 if (klist_node_attached(&dev->p->knode_bus))
582 klist_del(&dev->p->knode_bus);
583
584 pr_debug("bus: '%s': remove device %s\n",
585 dev->bus->name, dev_name(dev));
586 device_release_driver(dev);
587 bus_put(dev->bus);
588}
589
590static int driver_add_attrs(struct bus_type *bus, struct device_driver *drv)
591{
592 int error = 0;
593 int i;
594
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]);
598 if (error)
599 goto err;
600 }
601 }
602done:
603 return error;
604err:
605 while (--i >= 0)
606 driver_remove_file(drv, &bus->drv_attrs[i]);
607 goto done;
608}
609
610static void driver_remove_attrs(struct bus_type *bus,
611 struct device_driver *drv)
612{
613 int i;
614
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]);
618 }
619}
620
621#ifdef CONFIG_HOTPLUG
622/*
623 * Thanks to drivers making their tables __devinit, we can't allow manual
624 * bind and unbind from userspace unless CONFIG_HOTPLUG is enabled.
625 */
626static int __must_check add_bind_files(struct device_driver *drv)
627{
628 int ret;
629
630 ret = driver_create_file(drv, &driver_attr_unbind);
631 if (ret == 0) {
632 ret = driver_create_file(drv, &driver_attr_bind);
633 if (ret)
634 driver_remove_file(drv, &driver_attr_unbind);
635 }
636 return ret;
637}
638
639static void remove_bind_files(struct device_driver *drv)
640{
641 driver_remove_file(drv, &driver_attr_bind);
642 driver_remove_file(drv, &driver_attr_unbind);
643}
644
645static BUS_ATTR(drivers_probe, S_IWUSR, NULL, store_drivers_probe);
646static BUS_ATTR(drivers_autoprobe, S_IWUSR | S_IRUGO,
647 show_drivers_autoprobe, store_drivers_autoprobe);
648
649static int add_probe_files(struct bus_type *bus)
650{
651 int retval;
652
653 retval = bus_create_file(bus, &bus_attr_drivers_probe);
654 if (retval)
655 goto out;
656
657 retval = bus_create_file(bus, &bus_attr_drivers_autoprobe);
658 if (retval)
659 bus_remove_file(bus, &bus_attr_drivers_probe);
660out:
661 return retval;
662}
663
664static void remove_probe_files(struct bus_type *bus)
665{
666 bus_remove_file(bus, &bus_attr_drivers_autoprobe);
667 bus_remove_file(bus, &bus_attr_drivers_probe);
668}
669#else
670static inline int add_bind_files(struct device_driver *drv) { return 0; }
671static inline void remove_bind_files(struct device_driver *drv) {}
672static inline int add_probe_files(struct bus_type *bus) { return 0; }
673static inline void remove_probe_files(struct bus_type *bus) {}
674#endif
675
676static ssize_t driver_uevent_store(struct device_driver *drv,
677 const char *buf, size_t count)
678{
679 enum kobject_action action;
680
681 if (kobject_action_type(buf, count, &action) == 0)
682 kobject_uevent(&drv->p->kobj, action);
683 return count;
684}
685static DRIVER_ATTR(uevent, S_IWUSR, NULL, driver_uevent_store);
686
687/**
688 * bus_add_driver - Add a driver to the bus.
689 * @drv: driver.
690 */
691int bus_add_driver(struct device_driver *drv)
692{
693 struct bus_type *bus;
694 struct driver_private *priv;
695 int error = 0;
696
697 bus = bus_get(drv->bus);
698 if (!bus)
699 return -EINVAL;
700
701 pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name);
702
703 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
704 if (!priv) {
705 error = -ENOMEM;
706 goto out_put_bus;
707 }
708 klist_init(&priv->klist_devices, NULL, NULL);
709 priv->driver = drv;
710 drv->p = priv;
711 priv->kobj.kset = bus->p->drivers_kset;
712 error = kobject_init_and_add(&priv->kobj, &driver_ktype, NULL,
713 "%s", drv->name);
714 if (error)
715 goto out_unregister;
716
717 if (drv->bus->p->drivers_autoprobe) {
718 error = driver_attach(drv);
719 if (error)
720 goto out_unregister;
721 }
722 klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers);
723 module_add_driver(drv->owner, drv);
724
725 error = driver_create_file(drv, &driver_attr_uevent);
726 if (error) {
727 printk(KERN_ERR "%s: uevent attr (%s) failed\n",
728 __func__, drv->name);
729 }
730 error = driver_add_attrs(bus, drv);
731 if (error) {
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);
735 }
736
737 if (!drv->suppress_bind_attrs) {
738 error = add_bind_files(drv);
739 if (error) {
740 /* Ditto */
741 printk(KERN_ERR "%s: add_bind_files(%s) failed\n",
742 __func__, drv->name);
743 }
744 }
745
746 kobject_uevent(&priv->kobj, KOBJ_ADD);
747 return 0;
748
749out_unregister:
750 kobject_put(&priv->kobj);
751 kfree(drv->p);
752 drv->p = NULL;
753out_put_bus:
754 bus_put(bus);
755 return error;
756}
757
758/**
759 * bus_remove_driver - delete driver from bus's knowledge.
760 * @drv: driver.
761 *
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().
765 */
766void bus_remove_driver(struct device_driver *drv)
767{
768 if (!drv->bus)
769 return;
770
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);
777 driver_detach(drv);
778 module_remove_driver(drv);
779 kobject_put(&drv->p->kobj);
780 bus_put(drv->bus);
781}
782
783/* Helper for bus_rescan_devices's iter */
784static int __must_check bus_rescan_devices_helper(struct device *dev,
785 void *data)
786{
787 int ret = 0;
788
789 if (!dev->driver) {
790 if (dev->parent) /* Needed for USB */
791 device_lock(dev->parent);
792 ret = device_attach(dev);
793 if (dev->parent)
794 device_unlock(dev->parent);
795 }
796 return ret < 0 ? ret : 0;
797}
798
799/**
800 * bus_rescan_devices - rescan devices on the bus for possible drivers
801 * @bus: the bus to scan.
802 *
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.
806 */
807int bus_rescan_devices(struct bus_type *bus)
808{
809 return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
810}
811EXPORT_SYMBOL_GPL(bus_rescan_devices);
812
813/**
814 * device_reprobe - remove driver for a device and probe for a new driver
815 * @dev: the device to reprobe
816 *
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.
821 */
822int device_reprobe(struct device *dev)
823{
824 if (dev->driver) {
825 if (dev->parent) /* Needed for USB */
826 device_lock(dev->parent);
827 device_release_driver(dev);
828 if (dev->parent)
829 device_unlock(dev->parent);
830 }
831 return bus_rescan_devices_helper(dev, NULL);
832}
833EXPORT_SYMBOL_GPL(device_reprobe);
834
835/**
836 * find_bus - locate bus by name.
837 * @name: name of bus.
838 *
839 * Call kset_find_obj() to iterate over list of buses to
840 * find a bus by name. Return bus if found.
841 *
842 * Note that kset_find_obj increments bus' reference count.
843 */
844#if 0
845struct bus_type *find_bus(char *name)
846{
847 struct kobject *k = kset_find_obj(bus_kset, name);
848 return k ? to_bus(k) : NULL;
849}
850#endif /* 0 */
851
852
853/**
854 * bus_add_attrs - Add default attributes for this bus.
855 * @bus: Bus that has just been registered.
856 */
857
858static int bus_add_attrs(struct bus_type *bus)
859{
860 int error = 0;
861 int i;
862
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]);
866 if (error)
867 goto err;
868 }
869 }
870done:
871 return error;
872err:
873 while (--i >= 0)
874 bus_remove_file(bus, &bus->bus_attrs[i]);
875 goto done;
876}
877
878static void bus_remove_attrs(struct bus_type *bus)
879{
880 int i;
881
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]);
885 }
886}
887
888static void klist_devices_get(struct klist_node *n)
889{
890 struct device_private *dev_prv = to_device_private_bus(n);
891 struct device *dev = dev_prv->device;
892
893 get_device(dev);
894}
895
896static void klist_devices_put(struct klist_node *n)
897{
898 struct device_private *dev_prv = to_device_private_bus(n);
899 struct device *dev = dev_prv->device;
900
901 put_device(dev);
902}
903
904static ssize_t bus_uevent_store(struct bus_type *bus,
905 const char *buf, size_t count)
906{
907 enum kobject_action action;
908
909 if (kobject_action_type(buf, count, &action) == 0)
910 kobject_uevent(&bus->p->subsys.kobj, action);
911 return count;
912}
913static BUS_ATTR(uevent, S_IWUSR, NULL, bus_uevent_store);
914
915/**
916 * __bus_register - register a driver-core subsystem
917 * @bus: bus to register
918 * @key: lockdep class key
919 *
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.
923 */
924int __bus_register(struct bus_type *bus, struct lock_class_key *key)
925{
926 int retval;
927 struct subsys_private *priv;
928
929 priv = kzalloc(sizeof(struct subsys_private), GFP_KERNEL);
930 if (!priv)
931 return -ENOMEM;
932
933 priv->bus = bus;
934 bus->p = priv;
935
936 BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier);
937
938 retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name);
939 if (retval)
940 goto out;
941
942 priv->subsys.kobj.kset = bus_kset;
943 priv->subsys.kobj.ktype = &bus_ktype;
944 priv->drivers_autoprobe = 1;
945
946 retval = kset_register(&priv->subsys);
947 if (retval)
948 goto out;
949
950 retval = bus_create_file(bus, &bus_attr_uevent);
951 if (retval)
952 goto bus_uevent_fail;
953
954 priv->devices_kset = kset_create_and_add("devices", NULL,
955 &priv->subsys.kobj);
956 if (!priv->devices_kset) {
957 retval = -ENOMEM;
958 goto bus_devices_fail;
959 }
960
961 priv->drivers_kset = kset_create_and_add("drivers", NULL,
962 &priv->subsys.kobj);
963 if (!priv->drivers_kset) {
964 retval = -ENOMEM;
965 goto bus_drivers_fail;
966 }
967
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);
972
973 retval = add_probe_files(bus);
974 if (retval)
975 goto bus_probe_files_fail;
976
977 retval = bus_add_attrs(bus);
978 if (retval)
979 goto bus_attrs_fail;
980
981 pr_debug("bus: '%s': registered\n", bus->name);
982 return 0;
983
984bus_attrs_fail:
985 remove_probe_files(bus);
986bus_probe_files_fail:
987 kset_unregister(bus->p->drivers_kset);
988bus_drivers_fail:
989 kset_unregister(bus->p->devices_kset);
990bus_devices_fail:
991 bus_remove_file(bus, &bus_attr_uevent);
992bus_uevent_fail:
993 kset_unregister(&bus->p->subsys);
994out:
995 kfree(bus->p);
996 bus->p = NULL;
997 return retval;
998}
999EXPORT_SYMBOL_GPL(__bus_register);
1000
1001/**
1002 * bus_unregister - remove a bus from the system
1003 * @bus: bus.
1004 *
1005 * Unregister the child subsystems and the bus itself.
1006 * Finally, we call bus_put() to release the refcount
1007 */
1008void bus_unregister(struct bus_type *bus)
1009{
1010 pr_debug("bus: '%s': unregistering\n", bus->name);
1011 if (bus->dev_root)
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);
1019 kfree(bus->p);
1020 bus->p = NULL;
1021}
1022EXPORT_SYMBOL_GPL(bus_unregister);
1023
1024int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
1025{
1026 return blocking_notifier_chain_register(&bus->p->bus_notifier, nb);
1027}
1028EXPORT_SYMBOL_GPL(bus_register_notifier);
1029
1030int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
1031{
1032 return blocking_notifier_chain_unregister(&bus->p->bus_notifier, nb);
1033}
1034EXPORT_SYMBOL_GPL(bus_unregister_notifier);
1035
1036struct kset *bus_get_kset(struct bus_type *bus)
1037{
1038 return &bus->p->subsys;
1039}
1040EXPORT_SYMBOL_GPL(bus_get_kset);
1041
1042struct klist *bus_get_device_klist(struct bus_type *bus)
1043{
1044 return &bus->p->klist_devices;
1045}
1046EXPORT_SYMBOL_GPL(bus_get_device_klist);
1047
1048/*
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.
1054 */
1055static void device_insertion_sort_klist(struct device *a, struct list_head *list,
1056 int (*compare)(const struct device *a,
1057 const struct device *b))
1058{
1059 struct list_head *pos;
1060 struct klist_node *n;
1061 struct device_private *dev_prv;
1062 struct device *b;
1063
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);
1071 return;
1072 }
1073 }
1074 list_move_tail(&a->p->knode_bus.n_node, list);
1075}
1076
1077void bus_sort_breadthfirst(struct bus_type *bus,
1078 int (*compare)(const struct device *a,
1079 const struct device *b))
1080{
1081 LIST_HEAD(sorted_devices);
1082 struct list_head *pos, *tmp;
1083 struct klist_node *n;
1084 struct device_private *dev_prv;
1085 struct device *dev;
1086 struct klist *device_klist;
1087
1088 device_klist = bus_get_device_klist(bus);
1089
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);
1096 }
1097 list_splice(&sorted_devices, &device_klist->k_list);
1098 spin_unlock(&device_klist->k_lock);
1099}
1100EXPORT_SYMBOL_GPL(bus_sort_breadthfirst);
1101
1102/**
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
1108 *
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
1112 * the list.
1113 */
1114void subsys_dev_iter_init(struct subsys_dev_iter *iter, struct bus_type *subsys,
1115 struct device *start, const struct device_type *type)
1116{
1117 struct klist_node *start_knode = NULL;
1118
1119 if (start)
1120 start_knode = &start->p->knode_bus;
1121 klist_iter_init_node(&subsys->p->klist_devices, &iter->ki, start_knode);
1122 iter->type = type;
1123}
1124EXPORT_SYMBOL_GPL(subsys_dev_iter_init);
1125
1126/**
1127 * subsys_dev_iter_next - iterate to the next device
1128 * @iter: subsys iterator to proceed
1129 *
1130 * Proceed @iter to the next device and return it. Returns NULL if
1131 * iteration is complete.
1132 *
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.
1137 */
1138struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter)
1139{
1140 struct klist_node *knode;
1141 struct device *dev;
1142
1143 for (;;) {
1144 knode = klist_next(&iter->ki);
1145 if (!knode)
1146 return NULL;
1147 dev = container_of(knode, struct device_private, knode_bus)->device;
1148 if (!iter->type || iter->type == dev->type)
1149 return dev;
1150 }
1151}
1152EXPORT_SYMBOL_GPL(subsys_dev_iter_next);
1153
1154/**
1155 * subsys_dev_iter_exit - finish iteration
1156 * @iter: subsys iterator to finish
1157 *
1158 * Finish an iteration. Always call this function after iteration is
1159 * complete whether the iteration ran till the end or not.
1160 */
1161void subsys_dev_iter_exit(struct subsys_dev_iter *iter)
1162{
1163 klist_iter_exit(&iter->ki);
1164}
1165EXPORT_SYMBOL_GPL(subsys_dev_iter_exit);
1166
1167int subsys_interface_register(struct subsys_interface *sif)
1168{
1169 struct bus_type *subsys;
1170 struct subsys_dev_iter iter;
1171 struct device *dev;
1172
1173 if (!sif || !sif->subsys)
1174 return -ENODEV;
1175
1176 subsys = bus_get(sif->subsys);
1177 if (!subsys)
1178 return -EINVAL;
1179
1180 mutex_lock(&subsys->p->mutex);
1181 list_add_tail(&sif->node, &subsys->p->interfaces);
1182 if (sif->add_dev) {
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);
1187 }
1188 mutex_unlock(&subsys->p->mutex);
1189
1190 return 0;
1191}
1192EXPORT_SYMBOL_GPL(subsys_interface_register);
1193
1194void subsys_interface_unregister(struct subsys_interface *sif)
1195{
1196 struct bus_type *subsys;
1197 struct subsys_dev_iter iter;
1198 struct device *dev;
1199
1200 if (!sif || !sif->subsys)
1201 return;
1202
1203 subsys = sif->subsys;
1204
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);
1212 }
1213 mutex_unlock(&subsys->p->mutex);
1214
1215 bus_put(subsys);
1216}
1217EXPORT_SYMBOL_GPL(subsys_interface_unregister);
1218
1219static void system_root_device_release(struct device *dev)
1220{
1221 kfree(dev);
1222}
1223/**
1224 * subsys_system_register - register a subsystem at /sys/devices/system/
1225 * @subsys: system subsystem
1226 * @groups: default attributes for the root device
1227 *
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.
1234 *
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>.
1240 */
1241int subsys_system_register(struct bus_type *subsys,
1242 const struct attribute_group **groups)
1243{
1244 struct device *dev;
1245 int err;
1246
1247 err = bus_register(subsys);
1248 if (err < 0)
1249 return err;
1250
1251 dev = kzalloc(sizeof(struct device), GFP_KERNEL);
1252 if (!dev) {
1253 err = -ENOMEM;
1254 goto err_dev;
1255 }
1256
1257 err = dev_set_name(dev, "%s", subsys->name);
1258 if (err < 0)
1259 goto err_name;
1260
1261 dev->kobj.parent = &system_kset->kobj;
1262 dev->groups = groups;
1263 dev->release = system_root_device_release;
1264
1265 err = device_register(dev);
1266 if (err < 0)
1267 goto err_dev_reg;
1268
1269 subsys->dev_root = dev;
1270 return 0;
1271
1272err_dev_reg:
1273 put_device(dev);
1274 dev = NULL;
1275err_name:
1276 kfree(dev);
1277err_dev:
1278 bus_unregister(subsys);
1279 return err;
1280}
1281EXPORT_SYMBOL_GPL(subsys_system_register);
1282
1283int __init buses_init(void)
1284{
1285 bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);
1286 if (!bus_kset)
1287 return -ENOMEM;
1288
1289 system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj);
1290 if (!system_kset)
1291 return -ENOMEM;
1292
1293 return 0;
1294}