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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * class.c - basic device class management
4 *
5 * Copyright (c) 2002-3 Patrick Mochel
6 * Copyright (c) 2002-3 Open Source Development Labs
7 * Copyright (c) 2003-2004 Greg Kroah-Hartman
8 * Copyright (c) 2003-2004 IBM Corp.
9 */
10
11#include <linux/device/class.h>
12#include <linux/device.h>
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/string.h>
16#include <linux/kdev_t.h>
17#include <linux/err.h>
18#include <linux/slab.h>
19#include <linux/blkdev.h>
20#include <linux/mutex.h>
21#include "base.h"
22
23#define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
24
25static ssize_t class_attr_show(struct kobject *kobj, struct attribute *attr,
26 char *buf)
27{
28 struct class_attribute *class_attr = to_class_attr(attr);
29 struct subsys_private *cp = to_subsys_private(kobj);
30 ssize_t ret = -EIO;
31
32 if (class_attr->show)
33 ret = class_attr->show(cp->class, class_attr, buf);
34 return ret;
35}
36
37static ssize_t class_attr_store(struct kobject *kobj, struct attribute *attr,
38 const char *buf, size_t count)
39{
40 struct class_attribute *class_attr = to_class_attr(attr);
41 struct subsys_private *cp = to_subsys_private(kobj);
42 ssize_t ret = -EIO;
43
44 if (class_attr->store)
45 ret = class_attr->store(cp->class, class_attr, buf, count);
46 return ret;
47}
48
49static void class_release(struct kobject *kobj)
50{
51 struct subsys_private *cp = to_subsys_private(kobj);
52 struct class *class = cp->class;
53
54 pr_debug("class '%s': release.\n", class->name);
55
56 if (class->class_release)
57 class->class_release(class);
58 else
59 pr_debug("class '%s' does not have a release() function, "
60 "be careful\n", class->name);
61
62 kfree(cp);
63}
64
65static const struct kobj_ns_type_operations *class_child_ns_type(const struct kobject *kobj)
66{
67 struct subsys_private *cp = to_subsys_private(kobj);
68 struct class *class = cp->class;
69
70 return class->ns_type;
71}
72
73static const struct sysfs_ops class_sysfs_ops = {
74 .show = class_attr_show,
75 .store = class_attr_store,
76};
77
78static struct kobj_type class_ktype = {
79 .sysfs_ops = &class_sysfs_ops,
80 .release = class_release,
81 .child_ns_type = class_child_ns_type,
82};
83
84/* Hotplug events for classes go to the class subsys */
85static struct kset *class_kset;
86
87
88int class_create_file_ns(struct class *cls, const struct class_attribute *attr,
89 const void *ns)
90{
91 int error;
92
93 if (cls)
94 error = sysfs_create_file_ns(&cls->p->subsys.kobj,
95 &attr->attr, ns);
96 else
97 error = -EINVAL;
98 return error;
99}
100
101void class_remove_file_ns(struct class *cls, const struct class_attribute *attr,
102 const void *ns)
103{
104 if (cls)
105 sysfs_remove_file_ns(&cls->p->subsys.kobj, &attr->attr, ns);
106}
107
108static struct class *class_get(struct class *cls)
109{
110 if (cls)
111 kset_get(&cls->p->subsys);
112 return cls;
113}
114
115static void class_put(struct class *cls)
116{
117 if (cls)
118 kset_put(&cls->p->subsys);
119}
120
121static struct device *klist_class_to_dev(struct klist_node *n)
122{
123 struct device_private *p = to_device_private_class(n);
124 return p->device;
125}
126
127static void klist_class_dev_get(struct klist_node *n)
128{
129 struct device *dev = klist_class_to_dev(n);
130
131 get_device(dev);
132}
133
134static void klist_class_dev_put(struct klist_node *n)
135{
136 struct device *dev = klist_class_to_dev(n);
137
138 put_device(dev);
139}
140
141static int class_add_groups(struct class *cls,
142 const struct attribute_group **groups)
143{
144 return sysfs_create_groups(&cls->p->subsys.kobj, groups);
145}
146
147static void class_remove_groups(struct class *cls,
148 const struct attribute_group **groups)
149{
150 return sysfs_remove_groups(&cls->p->subsys.kobj, groups);
151}
152
153int __class_register(struct class *cls, struct lock_class_key *key)
154{
155 struct subsys_private *cp;
156 int error;
157
158 pr_debug("device class '%s': registering\n", cls->name);
159
160 cp = kzalloc(sizeof(*cp), GFP_KERNEL);
161 if (!cp)
162 return -ENOMEM;
163 klist_init(&cp->klist_devices, klist_class_dev_get, klist_class_dev_put);
164 INIT_LIST_HEAD(&cp->interfaces);
165 kset_init(&cp->glue_dirs);
166 __mutex_init(&cp->mutex, "subsys mutex", key);
167 error = kobject_set_name(&cp->subsys.kobj, "%s", cls->name);
168 if (error) {
169 kfree(cp);
170 return error;
171 }
172
173 /* set the default /sys/dev directory for devices of this class */
174 if (!cls->dev_kobj)
175 cls->dev_kobj = sysfs_dev_char_kobj;
176
177#if defined(CONFIG_BLOCK)
178 /* let the block class directory show up in the root of sysfs */
179 if (!sysfs_deprecated || cls != &block_class)
180 cp->subsys.kobj.kset = class_kset;
181#else
182 cp->subsys.kobj.kset = class_kset;
183#endif
184 cp->subsys.kobj.ktype = &class_ktype;
185 cp->class = cls;
186 cls->p = cp;
187
188 error = kset_register(&cp->subsys);
189 if (error) {
190 kfree(cp);
191 return error;
192 }
193 error = class_add_groups(class_get(cls), cls->class_groups);
194 class_put(cls);
195 if (error) {
196 kobject_del(&cp->subsys.kobj);
197 kfree_const(cp->subsys.kobj.name);
198 kfree(cp);
199 }
200 return error;
201}
202EXPORT_SYMBOL_GPL(__class_register);
203
204void class_unregister(struct class *cls)
205{
206 pr_debug("device class '%s': unregistering\n", cls->name);
207 class_remove_groups(cls, cls->class_groups);
208 kset_unregister(&cls->p->subsys);
209}
210
211static void class_create_release(struct class *cls)
212{
213 pr_debug("%s called for %s\n", __func__, cls->name);
214 kfree(cls);
215}
216
217/**
218 * __class_create - create a struct class structure
219 * @owner: pointer to the module that is to "own" this struct class
220 * @name: pointer to a string for the name of this class.
221 * @key: the lock_class_key for this class; used by mutex lock debugging
222 *
223 * This is used to create a struct class pointer that can then be used
224 * in calls to device_create().
225 *
226 * Returns &struct class pointer on success, or ERR_PTR() on error.
227 *
228 * Note, the pointer created here is to be destroyed when finished by
229 * making a call to class_destroy().
230 */
231struct class *__class_create(struct module *owner, const char *name,
232 struct lock_class_key *key)
233{
234 struct class *cls;
235 int retval;
236
237 cls = kzalloc(sizeof(*cls), GFP_KERNEL);
238 if (!cls) {
239 retval = -ENOMEM;
240 goto error;
241 }
242
243 cls->name = name;
244 cls->owner = owner;
245 cls->class_release = class_create_release;
246
247 retval = __class_register(cls, key);
248 if (retval)
249 goto error;
250
251 return cls;
252
253error:
254 kfree(cls);
255 return ERR_PTR(retval);
256}
257EXPORT_SYMBOL_GPL(__class_create);
258
259/**
260 * class_destroy - destroys a struct class structure
261 * @cls: pointer to the struct class that is to be destroyed
262 *
263 * Note, the pointer to be destroyed must have been created with a call
264 * to class_create().
265 */
266void class_destroy(struct class *cls)
267{
268 if (IS_ERR_OR_NULL(cls))
269 return;
270
271 class_unregister(cls);
272}
273
274/**
275 * class_dev_iter_init - initialize class device iterator
276 * @iter: class iterator to initialize
277 * @class: the class we wanna iterate over
278 * @start: the device to start iterating from, if any
279 * @type: device_type of the devices to iterate over, NULL for all
280 *
281 * Initialize class iterator @iter such that it iterates over devices
282 * of @class. If @start is set, the list iteration will start there,
283 * otherwise if it is NULL, the iteration starts at the beginning of
284 * the list.
285 */
286void class_dev_iter_init(struct class_dev_iter *iter, struct class *class,
287 struct device *start, const struct device_type *type)
288{
289 struct klist_node *start_knode = NULL;
290
291 if (start)
292 start_knode = &start->p->knode_class;
293 klist_iter_init_node(&class->p->klist_devices, &iter->ki, start_knode);
294 iter->type = type;
295}
296EXPORT_SYMBOL_GPL(class_dev_iter_init);
297
298/**
299 * class_dev_iter_next - iterate to the next device
300 * @iter: class iterator to proceed
301 *
302 * Proceed @iter to the next device and return it. Returns NULL if
303 * iteration is complete.
304 *
305 * The returned device is referenced and won't be released till
306 * iterator is proceed to the next device or exited. The caller is
307 * free to do whatever it wants to do with the device including
308 * calling back into class code.
309 */
310struct device *class_dev_iter_next(struct class_dev_iter *iter)
311{
312 struct klist_node *knode;
313 struct device *dev;
314
315 while (1) {
316 knode = klist_next(&iter->ki);
317 if (!knode)
318 return NULL;
319 dev = klist_class_to_dev(knode);
320 if (!iter->type || iter->type == dev->type)
321 return dev;
322 }
323}
324EXPORT_SYMBOL_GPL(class_dev_iter_next);
325
326/**
327 * class_dev_iter_exit - finish iteration
328 * @iter: class iterator to finish
329 *
330 * Finish an iteration. Always call this function after iteration is
331 * complete whether the iteration ran till the end or not.
332 */
333void class_dev_iter_exit(struct class_dev_iter *iter)
334{
335 klist_iter_exit(&iter->ki);
336}
337EXPORT_SYMBOL_GPL(class_dev_iter_exit);
338
339/**
340 * class_for_each_device - device iterator
341 * @class: the class we're iterating
342 * @start: the device to start with in the list, if any.
343 * @data: data for the callback
344 * @fn: function to be called for each device
345 *
346 * Iterate over @class's list of devices, and call @fn for each,
347 * passing it @data. If @start is set, the list iteration will start
348 * there, otherwise if it is NULL, the iteration starts at the
349 * beginning of the list.
350 *
351 * We check the return of @fn each time. If it returns anything
352 * other than 0, we break out and return that value.
353 *
354 * @fn is allowed to do anything including calling back into class
355 * code. There's no locking restriction.
356 */
357int class_for_each_device(struct class *class, struct device *start,
358 void *data, int (*fn)(struct device *, void *))
359{
360 struct class_dev_iter iter;
361 struct device *dev;
362 int error = 0;
363
364 if (!class)
365 return -EINVAL;
366 if (!class->p) {
367 WARN(1, "%s called for class '%s' before it was initialized",
368 __func__, class->name);
369 return -EINVAL;
370 }
371
372 class_dev_iter_init(&iter, class, start, NULL);
373 while ((dev = class_dev_iter_next(&iter))) {
374 error = fn(dev, data);
375 if (error)
376 break;
377 }
378 class_dev_iter_exit(&iter);
379
380 return error;
381}
382EXPORT_SYMBOL_GPL(class_for_each_device);
383
384/**
385 * class_find_device - device iterator for locating a particular device
386 * @class: the class we're iterating
387 * @start: Device to begin with
388 * @data: data for the match function
389 * @match: function to check device
390 *
391 * This is similar to the class_for_each_dev() function above, but it
392 * returns a reference to a device that is 'found' for later use, as
393 * determined by the @match callback.
394 *
395 * The callback should return 0 if the device doesn't match and non-zero
396 * if it does. If the callback returns non-zero, this function will
397 * return to the caller and not iterate over any more devices.
398 *
399 * Note, you will need to drop the reference with put_device() after use.
400 *
401 * @match is allowed to do anything including calling back into class
402 * code. There's no locking restriction.
403 */
404struct device *class_find_device(struct class *class, struct device *start,
405 const void *data,
406 int (*match)(struct device *, const void *))
407{
408 struct class_dev_iter iter;
409 struct device *dev;
410
411 if (!class)
412 return NULL;
413 if (!class->p) {
414 WARN(1, "%s called for class '%s' before it was initialized",
415 __func__, class->name);
416 return NULL;
417 }
418
419 class_dev_iter_init(&iter, class, start, NULL);
420 while ((dev = class_dev_iter_next(&iter))) {
421 if (match(dev, data)) {
422 get_device(dev);
423 break;
424 }
425 }
426 class_dev_iter_exit(&iter);
427
428 return dev;
429}
430EXPORT_SYMBOL_GPL(class_find_device);
431
432int class_interface_register(struct class_interface *class_intf)
433{
434 struct class *parent;
435 struct class_dev_iter iter;
436 struct device *dev;
437
438 if (!class_intf || !class_intf->class)
439 return -ENODEV;
440
441 parent = class_get(class_intf->class);
442 if (!parent)
443 return -EINVAL;
444
445 mutex_lock(&parent->p->mutex);
446 list_add_tail(&class_intf->node, &parent->p->interfaces);
447 if (class_intf->add_dev) {
448 class_dev_iter_init(&iter, parent, NULL, NULL);
449 while ((dev = class_dev_iter_next(&iter)))
450 class_intf->add_dev(dev, class_intf);
451 class_dev_iter_exit(&iter);
452 }
453 mutex_unlock(&parent->p->mutex);
454
455 return 0;
456}
457
458void class_interface_unregister(struct class_interface *class_intf)
459{
460 struct class *parent = class_intf->class;
461 struct class_dev_iter iter;
462 struct device *dev;
463
464 if (!parent)
465 return;
466
467 mutex_lock(&parent->p->mutex);
468 list_del_init(&class_intf->node);
469 if (class_intf->remove_dev) {
470 class_dev_iter_init(&iter, parent, NULL, NULL);
471 while ((dev = class_dev_iter_next(&iter)))
472 class_intf->remove_dev(dev, class_intf);
473 class_dev_iter_exit(&iter);
474 }
475 mutex_unlock(&parent->p->mutex);
476
477 class_put(parent);
478}
479
480ssize_t show_class_attr_string(struct class *class,
481 struct class_attribute *attr, char *buf)
482{
483 struct class_attribute_string *cs;
484
485 cs = container_of(attr, struct class_attribute_string, attr);
486 return sysfs_emit(buf, "%s\n", cs->str);
487}
488
489EXPORT_SYMBOL_GPL(show_class_attr_string);
490
491struct class_compat {
492 struct kobject *kobj;
493};
494
495/**
496 * class_compat_register - register a compatibility class
497 * @name: the name of the class
498 *
499 * Compatibility class are meant as a temporary user-space compatibility
500 * workaround when converting a family of class devices to a bus devices.
501 */
502struct class_compat *class_compat_register(const char *name)
503{
504 struct class_compat *cls;
505
506 cls = kmalloc(sizeof(struct class_compat), GFP_KERNEL);
507 if (!cls)
508 return NULL;
509 cls->kobj = kobject_create_and_add(name, &class_kset->kobj);
510 if (!cls->kobj) {
511 kfree(cls);
512 return NULL;
513 }
514 return cls;
515}
516EXPORT_SYMBOL_GPL(class_compat_register);
517
518/**
519 * class_compat_unregister - unregister a compatibility class
520 * @cls: the class to unregister
521 */
522void class_compat_unregister(struct class_compat *cls)
523{
524 kobject_put(cls->kobj);
525 kfree(cls);
526}
527EXPORT_SYMBOL_GPL(class_compat_unregister);
528
529/**
530 * class_compat_create_link - create a compatibility class device link to
531 * a bus device
532 * @cls: the compatibility class
533 * @dev: the target bus device
534 * @device_link: an optional device to which a "device" link should be created
535 */
536int class_compat_create_link(struct class_compat *cls, struct device *dev,
537 struct device *device_link)
538{
539 int error;
540
541 error = sysfs_create_link(cls->kobj, &dev->kobj, dev_name(dev));
542 if (error)
543 return error;
544
545 /*
546 * Optionally add a "device" link (typically to the parent), as a
547 * class device would have one and we want to provide as much
548 * backwards compatibility as possible.
549 */
550 if (device_link) {
551 error = sysfs_create_link(&dev->kobj, &device_link->kobj,
552 "device");
553 if (error)
554 sysfs_remove_link(cls->kobj, dev_name(dev));
555 }
556
557 return error;
558}
559EXPORT_SYMBOL_GPL(class_compat_create_link);
560
561/**
562 * class_compat_remove_link - remove a compatibility class device link to
563 * a bus device
564 * @cls: the compatibility class
565 * @dev: the target bus device
566 * @device_link: an optional device to which a "device" link was previously
567 * created
568 */
569void class_compat_remove_link(struct class_compat *cls, struct device *dev,
570 struct device *device_link)
571{
572 if (device_link)
573 sysfs_remove_link(&dev->kobj, "device");
574 sysfs_remove_link(cls->kobj, dev_name(dev));
575}
576EXPORT_SYMBOL_GPL(class_compat_remove_link);
577
578int __init classes_init(void)
579{
580 class_kset = kset_create_and_add("class", NULL, NULL);
581 if (!class_kset)
582 return -ENOMEM;
583 return 0;
584}
585
586EXPORT_SYMBOL_GPL(class_create_file_ns);
587EXPORT_SYMBOL_GPL(class_remove_file_ns);
588EXPORT_SYMBOL_GPL(class_unregister);
589EXPORT_SYMBOL_GPL(class_destroy);
590
591EXPORT_SYMBOL_GPL(class_interface_register);
592EXPORT_SYMBOL_GPL(class_interface_unregister);
1/*
2 * class.c - basic device class management
3 *
4 * Copyright (c) 2002-3 Patrick Mochel
5 * Copyright (c) 2002-3 Open Source Development Labs
6 * Copyright (c) 2003-2004 Greg Kroah-Hartman
7 * Copyright (c) 2003-2004 IBM Corp.
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/init.h>
16#include <linux/string.h>
17#include <linux/kdev_t.h>
18#include <linux/err.h>
19#include <linux/slab.h>
20#include <linux/genhd.h>
21#include <linux/mutex.h>
22#include "base.h"
23
24#define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
25
26static ssize_t class_attr_show(struct kobject *kobj, struct attribute *attr,
27 char *buf)
28{
29 struct class_attribute *class_attr = to_class_attr(attr);
30 struct subsys_private *cp = to_subsys_private(kobj);
31 ssize_t ret = -EIO;
32
33 if (class_attr->show)
34 ret = class_attr->show(cp->class, class_attr, buf);
35 return ret;
36}
37
38static ssize_t class_attr_store(struct kobject *kobj, struct attribute *attr,
39 const char *buf, size_t count)
40{
41 struct class_attribute *class_attr = to_class_attr(attr);
42 struct subsys_private *cp = to_subsys_private(kobj);
43 ssize_t ret = -EIO;
44
45 if (class_attr->store)
46 ret = class_attr->store(cp->class, class_attr, buf, count);
47 return ret;
48}
49
50static void class_release(struct kobject *kobj)
51{
52 struct subsys_private *cp = to_subsys_private(kobj);
53 struct class *class = cp->class;
54
55 pr_debug("class '%s': release.\n", class->name);
56
57 if (class->class_release)
58 class->class_release(class);
59 else
60 pr_debug("class '%s' does not have a release() function, "
61 "be careful\n", class->name);
62
63 kfree(cp);
64}
65
66static const struct kobj_ns_type_operations *class_child_ns_type(struct kobject *kobj)
67{
68 struct subsys_private *cp = to_subsys_private(kobj);
69 struct class *class = cp->class;
70
71 return class->ns_type;
72}
73
74static const struct sysfs_ops class_sysfs_ops = {
75 .show = class_attr_show,
76 .store = class_attr_store,
77};
78
79static struct kobj_type class_ktype = {
80 .sysfs_ops = &class_sysfs_ops,
81 .release = class_release,
82 .child_ns_type = class_child_ns_type,
83};
84
85/* Hotplug events for classes go to the class subsys */
86static struct kset *class_kset;
87
88
89int class_create_file_ns(struct class *cls, const struct class_attribute *attr,
90 const void *ns)
91{
92 int error;
93
94 if (cls)
95 error = sysfs_create_file_ns(&cls->p->subsys.kobj,
96 &attr->attr, ns);
97 else
98 error = -EINVAL;
99 return error;
100}
101
102void class_remove_file_ns(struct class *cls, const struct class_attribute *attr,
103 const void *ns)
104{
105 if (cls)
106 sysfs_remove_file_ns(&cls->p->subsys.kobj, &attr->attr, ns);
107}
108
109static struct class *class_get(struct class *cls)
110{
111 if (cls)
112 kset_get(&cls->p->subsys);
113 return cls;
114}
115
116static void class_put(struct class *cls)
117{
118 if (cls)
119 kset_put(&cls->p->subsys);
120}
121
122static int add_class_attrs(struct class *cls)
123{
124 int i;
125 int error = 0;
126
127 if (cls->class_attrs) {
128 for (i = 0; cls->class_attrs[i].attr.name; i++) {
129 error = class_create_file(cls, &cls->class_attrs[i]);
130 if (error)
131 goto error;
132 }
133 }
134done:
135 return error;
136error:
137 while (--i >= 0)
138 class_remove_file(cls, &cls->class_attrs[i]);
139 goto done;
140}
141
142static void remove_class_attrs(struct class *cls)
143{
144 int i;
145
146 if (cls->class_attrs) {
147 for (i = 0; cls->class_attrs[i].attr.name; i++)
148 class_remove_file(cls, &cls->class_attrs[i]);
149 }
150}
151
152static void klist_class_dev_get(struct klist_node *n)
153{
154 struct device *dev = container_of(n, struct device, knode_class);
155
156 get_device(dev);
157}
158
159static void klist_class_dev_put(struct klist_node *n)
160{
161 struct device *dev = container_of(n, struct device, knode_class);
162
163 put_device(dev);
164}
165
166static int class_add_groups(struct class *cls,
167 const struct attribute_group **groups)
168{
169 return sysfs_create_groups(&cls->p->subsys.kobj, groups);
170}
171
172static void class_remove_groups(struct class *cls,
173 const struct attribute_group **groups)
174{
175 return sysfs_remove_groups(&cls->p->subsys.kobj, groups);
176}
177
178int __class_register(struct class *cls, struct lock_class_key *key)
179{
180 struct subsys_private *cp;
181 int error;
182
183 pr_debug("device class '%s': registering\n", cls->name);
184
185 cp = kzalloc(sizeof(*cp), GFP_KERNEL);
186 if (!cp)
187 return -ENOMEM;
188 klist_init(&cp->klist_devices, klist_class_dev_get, klist_class_dev_put);
189 INIT_LIST_HEAD(&cp->interfaces);
190 kset_init(&cp->glue_dirs);
191 __mutex_init(&cp->mutex, "subsys mutex", key);
192 error = kobject_set_name(&cp->subsys.kobj, "%s", cls->name);
193 if (error) {
194 kfree(cp);
195 return error;
196 }
197
198 /* set the default /sys/dev directory for devices of this class */
199 if (!cls->dev_kobj)
200 cls->dev_kobj = sysfs_dev_char_kobj;
201
202#if defined(CONFIG_BLOCK)
203 /* let the block class directory show up in the root of sysfs */
204 if (!sysfs_deprecated || cls != &block_class)
205 cp->subsys.kobj.kset = class_kset;
206#else
207 cp->subsys.kobj.kset = class_kset;
208#endif
209 cp->subsys.kobj.ktype = &class_ktype;
210 cp->class = cls;
211 cls->p = cp;
212
213 error = kset_register(&cp->subsys);
214 if (error) {
215 kfree(cp);
216 return error;
217 }
218 error = class_add_groups(class_get(cls), cls->class_groups);
219 class_put(cls);
220 error = add_class_attrs(class_get(cls));
221 class_put(cls);
222 return error;
223}
224EXPORT_SYMBOL_GPL(__class_register);
225
226void class_unregister(struct class *cls)
227{
228 pr_debug("device class '%s': unregistering\n", cls->name);
229 remove_class_attrs(cls);
230 class_remove_groups(cls, cls->class_groups);
231 kset_unregister(&cls->p->subsys);
232}
233
234static void class_create_release(struct class *cls)
235{
236 pr_debug("%s called for %s\n", __func__, cls->name);
237 kfree(cls);
238}
239
240/**
241 * class_create - create a struct class structure
242 * @owner: pointer to the module that is to "own" this struct class
243 * @name: pointer to a string for the name of this class.
244 * @key: the lock_class_key for this class; used by mutex lock debugging
245 *
246 * This is used to create a struct class pointer that can then be used
247 * in calls to device_create().
248 *
249 * Returns &struct class pointer on success, or ERR_PTR() on error.
250 *
251 * Note, the pointer created here is to be destroyed when finished by
252 * making a call to class_destroy().
253 */
254struct class *__class_create(struct module *owner, const char *name,
255 struct lock_class_key *key)
256{
257 struct class *cls;
258 int retval;
259
260 cls = kzalloc(sizeof(*cls), GFP_KERNEL);
261 if (!cls) {
262 retval = -ENOMEM;
263 goto error;
264 }
265
266 cls->name = name;
267 cls->owner = owner;
268 cls->class_release = class_create_release;
269
270 retval = __class_register(cls, key);
271 if (retval)
272 goto error;
273
274 return cls;
275
276error:
277 kfree(cls);
278 return ERR_PTR(retval);
279}
280EXPORT_SYMBOL_GPL(__class_create);
281
282/**
283 * class_destroy - destroys a struct class structure
284 * @cls: pointer to the struct class that is to be destroyed
285 *
286 * Note, the pointer to be destroyed must have been created with a call
287 * to class_create().
288 */
289void class_destroy(struct class *cls)
290{
291 if ((cls == NULL) || (IS_ERR(cls)))
292 return;
293
294 class_unregister(cls);
295}
296
297/**
298 * class_dev_iter_init - initialize class device iterator
299 * @iter: class iterator to initialize
300 * @class: the class we wanna iterate over
301 * @start: the device to start iterating from, if any
302 * @type: device_type of the devices to iterate over, NULL for all
303 *
304 * Initialize class iterator @iter such that it iterates over devices
305 * of @class. If @start is set, the list iteration will start there,
306 * otherwise if it is NULL, the iteration starts at the beginning of
307 * the list.
308 */
309void class_dev_iter_init(struct class_dev_iter *iter, struct class *class,
310 struct device *start, const struct device_type *type)
311{
312 struct klist_node *start_knode = NULL;
313
314 if (start)
315 start_knode = &start->knode_class;
316 klist_iter_init_node(&class->p->klist_devices, &iter->ki, start_knode);
317 iter->type = type;
318}
319EXPORT_SYMBOL_GPL(class_dev_iter_init);
320
321/**
322 * class_dev_iter_next - iterate to the next device
323 * @iter: class iterator to proceed
324 *
325 * Proceed @iter to the next device and return it. Returns NULL if
326 * iteration is complete.
327 *
328 * The returned device is referenced and won't be released till
329 * iterator is proceed to the next device or exited. The caller is
330 * free to do whatever it wants to do with the device including
331 * calling back into class code.
332 */
333struct device *class_dev_iter_next(struct class_dev_iter *iter)
334{
335 struct klist_node *knode;
336 struct device *dev;
337
338 while (1) {
339 knode = klist_next(&iter->ki);
340 if (!knode)
341 return NULL;
342 dev = container_of(knode, struct device, knode_class);
343 if (!iter->type || iter->type == dev->type)
344 return dev;
345 }
346}
347EXPORT_SYMBOL_GPL(class_dev_iter_next);
348
349/**
350 * class_dev_iter_exit - finish iteration
351 * @iter: class iterator to finish
352 *
353 * Finish an iteration. Always call this function after iteration is
354 * complete whether the iteration ran till the end or not.
355 */
356void class_dev_iter_exit(struct class_dev_iter *iter)
357{
358 klist_iter_exit(&iter->ki);
359}
360EXPORT_SYMBOL_GPL(class_dev_iter_exit);
361
362/**
363 * class_for_each_device - device iterator
364 * @class: the class we're iterating
365 * @start: the device to start with in the list, if any.
366 * @data: data for the callback
367 * @fn: function to be called for each device
368 *
369 * Iterate over @class's list of devices, and call @fn for each,
370 * passing it @data. If @start is set, the list iteration will start
371 * there, otherwise if it is NULL, the iteration starts at the
372 * beginning of the list.
373 *
374 * We check the return of @fn each time. If it returns anything
375 * other than 0, we break out and return that value.
376 *
377 * @fn is allowed to do anything including calling back into class
378 * code. There's no locking restriction.
379 */
380int class_for_each_device(struct class *class, struct device *start,
381 void *data, int (*fn)(struct device *, void *))
382{
383 struct class_dev_iter iter;
384 struct device *dev;
385 int error = 0;
386
387 if (!class)
388 return -EINVAL;
389 if (!class->p) {
390 WARN(1, "%s called for class '%s' before it was initialized",
391 __func__, class->name);
392 return -EINVAL;
393 }
394
395 class_dev_iter_init(&iter, class, start, NULL);
396 while ((dev = class_dev_iter_next(&iter))) {
397 error = fn(dev, data);
398 if (error)
399 break;
400 }
401 class_dev_iter_exit(&iter);
402
403 return error;
404}
405EXPORT_SYMBOL_GPL(class_for_each_device);
406
407/**
408 * class_find_device - device iterator for locating a particular device
409 * @class: the class we're iterating
410 * @start: Device to begin with
411 * @data: data for the match function
412 * @match: function to check device
413 *
414 * This is similar to the class_for_each_dev() function above, but it
415 * returns a reference to a device that is 'found' for later use, as
416 * determined by the @match callback.
417 *
418 * The callback should return 0 if the device doesn't match and non-zero
419 * if it does. If the callback returns non-zero, this function will
420 * return to the caller and not iterate over any more devices.
421 *
422 * Note, you will need to drop the reference with put_device() after use.
423 *
424 * @match is allowed to do anything including calling back into class
425 * code. There's no locking restriction.
426 */
427struct device *class_find_device(struct class *class, struct device *start,
428 const void *data,
429 int (*match)(struct device *, const void *))
430{
431 struct class_dev_iter iter;
432 struct device *dev;
433
434 if (!class)
435 return NULL;
436 if (!class->p) {
437 WARN(1, "%s called for class '%s' before it was initialized",
438 __func__, class->name);
439 return NULL;
440 }
441
442 class_dev_iter_init(&iter, class, start, NULL);
443 while ((dev = class_dev_iter_next(&iter))) {
444 if (match(dev, data)) {
445 get_device(dev);
446 break;
447 }
448 }
449 class_dev_iter_exit(&iter);
450
451 return dev;
452}
453EXPORT_SYMBOL_GPL(class_find_device);
454
455int class_interface_register(struct class_interface *class_intf)
456{
457 struct class *parent;
458 struct class_dev_iter iter;
459 struct device *dev;
460
461 if (!class_intf || !class_intf->class)
462 return -ENODEV;
463
464 parent = class_get(class_intf->class);
465 if (!parent)
466 return -EINVAL;
467
468 mutex_lock(&parent->p->mutex);
469 list_add_tail(&class_intf->node, &parent->p->interfaces);
470 if (class_intf->add_dev) {
471 class_dev_iter_init(&iter, parent, NULL, NULL);
472 while ((dev = class_dev_iter_next(&iter)))
473 class_intf->add_dev(dev, class_intf);
474 class_dev_iter_exit(&iter);
475 }
476 mutex_unlock(&parent->p->mutex);
477
478 return 0;
479}
480
481void class_interface_unregister(struct class_interface *class_intf)
482{
483 struct class *parent = class_intf->class;
484 struct class_dev_iter iter;
485 struct device *dev;
486
487 if (!parent)
488 return;
489
490 mutex_lock(&parent->p->mutex);
491 list_del_init(&class_intf->node);
492 if (class_intf->remove_dev) {
493 class_dev_iter_init(&iter, parent, NULL, NULL);
494 while ((dev = class_dev_iter_next(&iter)))
495 class_intf->remove_dev(dev, class_intf);
496 class_dev_iter_exit(&iter);
497 }
498 mutex_unlock(&parent->p->mutex);
499
500 class_put(parent);
501}
502
503ssize_t show_class_attr_string(struct class *class,
504 struct class_attribute *attr, char *buf)
505{
506 struct class_attribute_string *cs;
507
508 cs = container_of(attr, struct class_attribute_string, attr);
509 return snprintf(buf, PAGE_SIZE, "%s\n", cs->str);
510}
511
512EXPORT_SYMBOL_GPL(show_class_attr_string);
513
514struct class_compat {
515 struct kobject *kobj;
516};
517
518/**
519 * class_compat_register - register a compatibility class
520 * @name: the name of the class
521 *
522 * Compatibility class are meant as a temporary user-space compatibility
523 * workaround when converting a family of class devices to a bus devices.
524 */
525struct class_compat *class_compat_register(const char *name)
526{
527 struct class_compat *cls;
528
529 cls = kmalloc(sizeof(struct class_compat), GFP_KERNEL);
530 if (!cls)
531 return NULL;
532 cls->kobj = kobject_create_and_add(name, &class_kset->kobj);
533 if (!cls->kobj) {
534 kfree(cls);
535 return NULL;
536 }
537 return cls;
538}
539EXPORT_SYMBOL_GPL(class_compat_register);
540
541/**
542 * class_compat_unregister - unregister a compatibility class
543 * @cls: the class to unregister
544 */
545void class_compat_unregister(struct class_compat *cls)
546{
547 kobject_put(cls->kobj);
548 kfree(cls);
549}
550EXPORT_SYMBOL_GPL(class_compat_unregister);
551
552/**
553 * class_compat_create_link - create a compatibility class device link to
554 * a bus device
555 * @cls: the compatibility class
556 * @dev: the target bus device
557 * @device_link: an optional device to which a "device" link should be created
558 */
559int class_compat_create_link(struct class_compat *cls, struct device *dev,
560 struct device *device_link)
561{
562 int error;
563
564 error = sysfs_create_link(cls->kobj, &dev->kobj, dev_name(dev));
565 if (error)
566 return error;
567
568 /*
569 * Optionally add a "device" link (typically to the parent), as a
570 * class device would have one and we want to provide as much
571 * backwards compatibility as possible.
572 */
573 if (device_link) {
574 error = sysfs_create_link(&dev->kobj, &device_link->kobj,
575 "device");
576 if (error)
577 sysfs_remove_link(cls->kobj, dev_name(dev));
578 }
579
580 return error;
581}
582EXPORT_SYMBOL_GPL(class_compat_create_link);
583
584/**
585 * class_compat_remove_link - remove a compatibility class device link to
586 * a bus device
587 * @cls: the compatibility class
588 * @dev: the target bus device
589 * @device_link: an optional device to which a "device" link was previously
590 * created
591 */
592void class_compat_remove_link(struct class_compat *cls, struct device *dev,
593 struct device *device_link)
594{
595 if (device_link)
596 sysfs_remove_link(&dev->kobj, "device");
597 sysfs_remove_link(cls->kobj, dev_name(dev));
598}
599EXPORT_SYMBOL_GPL(class_compat_remove_link);
600
601int __init classes_init(void)
602{
603 class_kset = kset_create_and_add("class", NULL, NULL);
604 if (!class_kset)
605 return -ENOMEM;
606 return 0;
607}
608
609EXPORT_SYMBOL_GPL(class_create_file_ns);
610EXPORT_SYMBOL_GPL(class_remove_file_ns);
611EXPORT_SYMBOL_GPL(class_unregister);
612EXPORT_SYMBOL_GPL(class_destroy);
613
614EXPORT_SYMBOL_GPL(class_interface_register);
615EXPORT_SYMBOL_GPL(class_interface_unregister);