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1/*
2 * drivers/base/core.c - core driver model code (device registration, etc)
3 *
4 * Copyright (c) 2002-3 Patrick Mochel
5 * Copyright (c) 2002-3 Open Source Development Labs
6 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
7 * Copyright (c) 2006 Novell, Inc.
8 *
9 * This file is released under the GPLv2
10 *
11 */
12
13#include <linux/device.h>
14#include <linux/err.h>
15#include <linux/init.h>
16#include <linux/module.h>
17#include <linux/slab.h>
18#include <linux/string.h>
19#include <linux/kdev_t.h>
20#include <linux/notifier.h>
21#include <linux/genhd.h>
22#include <linux/kallsyms.h>
23#include <linux/mutex.h>
24#include <linux/async.h>
25
26#include "base.h"
27#include "power/power.h"
28
29#ifdef CONFIG_SYSFS_DEPRECATED
30#ifdef CONFIG_SYSFS_DEPRECATED_V2
31long sysfs_deprecated = 1;
32#else
33long sysfs_deprecated = 0;
34#endif
35static __init int sysfs_deprecated_setup(char *arg)
36{
37 return strict_strtol(arg, 10, &sysfs_deprecated);
38}
39early_param("sysfs.deprecated", sysfs_deprecated_setup);
40#endif
41
42int (*platform_notify)(struct device *dev) = NULL;
43int (*platform_notify_remove)(struct device *dev) = NULL;
44static struct kobject *dev_kobj;
45struct kobject *sysfs_dev_char_kobj;
46struct kobject *sysfs_dev_block_kobj;
47
48#ifdef CONFIG_BLOCK
49static inline int device_is_not_partition(struct device *dev)
50{
51 return !(dev->type == &part_type);
52}
53#else
54static inline int device_is_not_partition(struct device *dev)
55{
56 return 1;
57}
58#endif
59
60/**
61 * dev_driver_string - Return a device's driver name, if at all possible
62 * @dev: struct device to get the name of
63 *
64 * Will return the device's driver's name if it is bound to a device. If
65 * the device is not bound to a device, it will return the name of the bus
66 * it is attached to. If it is not attached to a bus either, an empty
67 * string will be returned.
68 */
69const char *dev_driver_string(const struct device *dev)
70{
71 struct device_driver *drv;
72
73 /* dev->driver can change to NULL underneath us because of unbinding,
74 * so be careful about accessing it. dev->bus and dev->class should
75 * never change once they are set, so they don't need special care.
76 */
77 drv = ACCESS_ONCE(dev->driver);
78 return drv ? drv->name :
79 (dev->bus ? dev->bus->name :
80 (dev->class ? dev->class->name : ""));
81}
82EXPORT_SYMBOL(dev_driver_string);
83
84#define to_dev(obj) container_of(obj, struct device, kobj)
85#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
86
87static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
88 char *buf)
89{
90 struct device_attribute *dev_attr = to_dev_attr(attr);
91 struct device *dev = to_dev(kobj);
92 ssize_t ret = -EIO;
93
94 if (dev_attr->show)
95 ret = dev_attr->show(dev, dev_attr, buf);
96 if (ret >= (ssize_t)PAGE_SIZE) {
97 print_symbol("dev_attr_show: %s returned bad count\n",
98 (unsigned long)dev_attr->show);
99 }
100 return ret;
101}
102
103static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
104 const char *buf, size_t count)
105{
106 struct device_attribute *dev_attr = to_dev_attr(attr);
107 struct device *dev = to_dev(kobj);
108 ssize_t ret = -EIO;
109
110 if (dev_attr->store)
111 ret = dev_attr->store(dev, dev_attr, buf, count);
112 return ret;
113}
114
115static const struct sysfs_ops dev_sysfs_ops = {
116 .show = dev_attr_show,
117 .store = dev_attr_store,
118};
119
120
121/**
122 * device_release - free device structure.
123 * @kobj: device's kobject.
124 *
125 * This is called once the reference count for the object
126 * reaches 0. We forward the call to the device's release
127 * method, which should handle actually freeing the structure.
128 */
129static void device_release(struct kobject *kobj)
130{
131 struct device *dev = to_dev(kobj);
132 struct device_private *p = dev->p;
133
134 if (dev->release)
135 dev->release(dev);
136 else if (dev->type && dev->type->release)
137 dev->type->release(dev);
138 else if (dev->class && dev->class->dev_release)
139 dev->class->dev_release(dev);
140 else
141 WARN(1, KERN_ERR "Device '%s' does not have a release() "
142 "function, it is broken and must be fixed.\n",
143 dev_name(dev));
144 kfree(p);
145}
146
147static const void *device_namespace(struct kobject *kobj)
148{
149 struct device *dev = to_dev(kobj);
150 const void *ns = NULL;
151
152 if (dev->class && dev->class->ns_type)
153 ns = dev->class->namespace(dev);
154
155 return ns;
156}
157
158static struct kobj_type device_ktype = {
159 .release = device_release,
160 .sysfs_ops = &dev_sysfs_ops,
161 .namespace = device_namespace,
162};
163
164
165static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
166{
167 struct kobj_type *ktype = get_ktype(kobj);
168
169 if (ktype == &device_ktype) {
170 struct device *dev = to_dev(kobj);
171 if (dev->bus)
172 return 1;
173 if (dev->class)
174 return 1;
175 }
176 return 0;
177}
178
179static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
180{
181 struct device *dev = to_dev(kobj);
182
183 if (dev->bus)
184 return dev->bus->name;
185 if (dev->class)
186 return dev->class->name;
187 return NULL;
188}
189
190static int dev_uevent(struct kset *kset, struct kobject *kobj,
191 struct kobj_uevent_env *env)
192{
193 struct device *dev = to_dev(kobj);
194 int retval = 0;
195
196 /* add device node properties if present */
197 if (MAJOR(dev->devt)) {
198 const char *tmp;
199 const char *name;
200 mode_t mode = 0;
201
202 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
203 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
204 name = device_get_devnode(dev, &mode, &tmp);
205 if (name) {
206 add_uevent_var(env, "DEVNAME=%s", name);
207 kfree(tmp);
208 if (mode)
209 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
210 }
211 }
212
213 if (dev->type && dev->type->name)
214 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
215
216 if (dev->driver)
217 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
218
219 /* have the bus specific function add its stuff */
220 if (dev->bus && dev->bus->uevent) {
221 retval = dev->bus->uevent(dev, env);
222 if (retval)
223 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
224 dev_name(dev), __func__, retval);
225 }
226
227 /* have the class specific function add its stuff */
228 if (dev->class && dev->class->dev_uevent) {
229 retval = dev->class->dev_uevent(dev, env);
230 if (retval)
231 pr_debug("device: '%s': %s: class uevent() "
232 "returned %d\n", dev_name(dev),
233 __func__, retval);
234 }
235
236 /* have the device type specific function add its stuff */
237 if (dev->type && dev->type->uevent) {
238 retval = dev->type->uevent(dev, env);
239 if (retval)
240 pr_debug("device: '%s': %s: dev_type uevent() "
241 "returned %d\n", dev_name(dev),
242 __func__, retval);
243 }
244
245 return retval;
246}
247
248static const struct kset_uevent_ops device_uevent_ops = {
249 .filter = dev_uevent_filter,
250 .name = dev_uevent_name,
251 .uevent = dev_uevent,
252};
253
254static ssize_t show_uevent(struct device *dev, struct device_attribute *attr,
255 char *buf)
256{
257 struct kobject *top_kobj;
258 struct kset *kset;
259 struct kobj_uevent_env *env = NULL;
260 int i;
261 size_t count = 0;
262 int retval;
263
264 /* search the kset, the device belongs to */
265 top_kobj = &dev->kobj;
266 while (!top_kobj->kset && top_kobj->parent)
267 top_kobj = top_kobj->parent;
268 if (!top_kobj->kset)
269 goto out;
270
271 kset = top_kobj->kset;
272 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
273 goto out;
274
275 /* respect filter */
276 if (kset->uevent_ops && kset->uevent_ops->filter)
277 if (!kset->uevent_ops->filter(kset, &dev->kobj))
278 goto out;
279
280 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
281 if (!env)
282 return -ENOMEM;
283
284 /* let the kset specific function add its keys */
285 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
286 if (retval)
287 goto out;
288
289 /* copy keys to file */
290 for (i = 0; i < env->envp_idx; i++)
291 count += sprintf(&buf[count], "%s\n", env->envp[i]);
292out:
293 kfree(env);
294 return count;
295}
296
297static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
298 const char *buf, size_t count)
299{
300 enum kobject_action action;
301
302 if (kobject_action_type(buf, count, &action) == 0)
303 kobject_uevent(&dev->kobj, action);
304 else
305 dev_err(dev, "uevent: unknown action-string\n");
306 return count;
307}
308
309static struct device_attribute uevent_attr =
310 __ATTR(uevent, S_IRUGO | S_IWUSR, show_uevent, store_uevent);
311
312static int device_add_attributes(struct device *dev,
313 struct device_attribute *attrs)
314{
315 int error = 0;
316 int i;
317
318 if (attrs) {
319 for (i = 0; attr_name(attrs[i]); i++) {
320 error = device_create_file(dev, &attrs[i]);
321 if (error)
322 break;
323 }
324 if (error)
325 while (--i >= 0)
326 device_remove_file(dev, &attrs[i]);
327 }
328 return error;
329}
330
331static void device_remove_attributes(struct device *dev,
332 struct device_attribute *attrs)
333{
334 int i;
335
336 if (attrs)
337 for (i = 0; attr_name(attrs[i]); i++)
338 device_remove_file(dev, &attrs[i]);
339}
340
341static int device_add_bin_attributes(struct device *dev,
342 struct bin_attribute *attrs)
343{
344 int error = 0;
345 int i;
346
347 if (attrs) {
348 for (i = 0; attr_name(attrs[i]); i++) {
349 error = device_create_bin_file(dev, &attrs[i]);
350 if (error)
351 break;
352 }
353 if (error)
354 while (--i >= 0)
355 device_remove_bin_file(dev, &attrs[i]);
356 }
357 return error;
358}
359
360static void device_remove_bin_attributes(struct device *dev,
361 struct bin_attribute *attrs)
362{
363 int i;
364
365 if (attrs)
366 for (i = 0; attr_name(attrs[i]); i++)
367 device_remove_bin_file(dev, &attrs[i]);
368}
369
370static int device_add_groups(struct device *dev,
371 const struct attribute_group **groups)
372{
373 int error = 0;
374 int i;
375
376 if (groups) {
377 for (i = 0; groups[i]; i++) {
378 error = sysfs_create_group(&dev->kobj, groups[i]);
379 if (error) {
380 while (--i >= 0)
381 sysfs_remove_group(&dev->kobj,
382 groups[i]);
383 break;
384 }
385 }
386 }
387 return error;
388}
389
390static void device_remove_groups(struct device *dev,
391 const struct attribute_group **groups)
392{
393 int i;
394
395 if (groups)
396 for (i = 0; groups[i]; i++)
397 sysfs_remove_group(&dev->kobj, groups[i]);
398}
399
400static int device_add_attrs(struct device *dev)
401{
402 struct class *class = dev->class;
403 const struct device_type *type = dev->type;
404 int error;
405
406 if (class) {
407 error = device_add_attributes(dev, class->dev_attrs);
408 if (error)
409 return error;
410 error = device_add_bin_attributes(dev, class->dev_bin_attrs);
411 if (error)
412 goto err_remove_class_attrs;
413 }
414
415 if (type) {
416 error = device_add_groups(dev, type->groups);
417 if (error)
418 goto err_remove_class_bin_attrs;
419 }
420
421 error = device_add_groups(dev, dev->groups);
422 if (error)
423 goto err_remove_type_groups;
424
425 return 0;
426
427 err_remove_type_groups:
428 if (type)
429 device_remove_groups(dev, type->groups);
430 err_remove_class_bin_attrs:
431 if (class)
432 device_remove_bin_attributes(dev, class->dev_bin_attrs);
433 err_remove_class_attrs:
434 if (class)
435 device_remove_attributes(dev, class->dev_attrs);
436
437 return error;
438}
439
440static void device_remove_attrs(struct device *dev)
441{
442 struct class *class = dev->class;
443 const struct device_type *type = dev->type;
444
445 device_remove_groups(dev, dev->groups);
446
447 if (type)
448 device_remove_groups(dev, type->groups);
449
450 if (class) {
451 device_remove_attributes(dev, class->dev_attrs);
452 device_remove_bin_attributes(dev, class->dev_bin_attrs);
453 }
454}
455
456
457static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
458 char *buf)
459{
460 return print_dev_t(buf, dev->devt);
461}
462
463static struct device_attribute devt_attr =
464 __ATTR(dev, S_IRUGO, show_dev, NULL);
465
466/* kset to create /sys/devices/ */
467struct kset *devices_kset;
468
469/**
470 * device_create_file - create sysfs attribute file for device.
471 * @dev: device.
472 * @attr: device attribute descriptor.
473 */
474int device_create_file(struct device *dev,
475 const struct device_attribute *attr)
476{
477 int error = 0;
478 if (dev)
479 error = sysfs_create_file(&dev->kobj, &attr->attr);
480 return error;
481}
482
483/**
484 * device_remove_file - remove sysfs attribute file.
485 * @dev: device.
486 * @attr: device attribute descriptor.
487 */
488void device_remove_file(struct device *dev,
489 const struct device_attribute *attr)
490{
491 if (dev)
492 sysfs_remove_file(&dev->kobj, &attr->attr);
493}
494
495/**
496 * device_create_bin_file - create sysfs binary attribute file for device.
497 * @dev: device.
498 * @attr: device binary attribute descriptor.
499 */
500int device_create_bin_file(struct device *dev,
501 const struct bin_attribute *attr)
502{
503 int error = -EINVAL;
504 if (dev)
505 error = sysfs_create_bin_file(&dev->kobj, attr);
506 return error;
507}
508EXPORT_SYMBOL_GPL(device_create_bin_file);
509
510/**
511 * device_remove_bin_file - remove sysfs binary attribute file
512 * @dev: device.
513 * @attr: device binary attribute descriptor.
514 */
515void device_remove_bin_file(struct device *dev,
516 const struct bin_attribute *attr)
517{
518 if (dev)
519 sysfs_remove_bin_file(&dev->kobj, attr);
520}
521EXPORT_SYMBOL_GPL(device_remove_bin_file);
522
523/**
524 * device_schedule_callback_owner - helper to schedule a callback for a device
525 * @dev: device.
526 * @func: callback function to invoke later.
527 * @owner: module owning the callback routine
528 *
529 * Attribute methods must not unregister themselves or their parent device
530 * (which would amount to the same thing). Attempts to do so will deadlock,
531 * since unregistration is mutually exclusive with driver callbacks.
532 *
533 * Instead methods can call this routine, which will attempt to allocate
534 * and schedule a workqueue request to call back @func with @dev as its
535 * argument in the workqueue's process context. @dev will be pinned until
536 * @func returns.
537 *
538 * This routine is usually called via the inline device_schedule_callback(),
539 * which automatically sets @owner to THIS_MODULE.
540 *
541 * Returns 0 if the request was submitted, -ENOMEM if storage could not
542 * be allocated, -ENODEV if a reference to @owner isn't available.
543 *
544 * NOTE: This routine won't work if CONFIG_SYSFS isn't set! It uses an
545 * underlying sysfs routine (since it is intended for use by attribute
546 * methods), and if sysfs isn't available you'll get nothing but -ENOSYS.
547 */
548int device_schedule_callback_owner(struct device *dev,
549 void (*func)(struct device *), struct module *owner)
550{
551 return sysfs_schedule_callback(&dev->kobj,
552 (void (*)(void *)) func, dev, owner);
553}
554EXPORT_SYMBOL_GPL(device_schedule_callback_owner);
555
556static void klist_children_get(struct klist_node *n)
557{
558 struct device_private *p = to_device_private_parent(n);
559 struct device *dev = p->device;
560
561 get_device(dev);
562}
563
564static void klist_children_put(struct klist_node *n)
565{
566 struct device_private *p = to_device_private_parent(n);
567 struct device *dev = p->device;
568
569 put_device(dev);
570}
571
572/**
573 * device_initialize - init device structure.
574 * @dev: device.
575 *
576 * This prepares the device for use by other layers by initializing
577 * its fields.
578 * It is the first half of device_register(), if called by
579 * that function, though it can also be called separately, so one
580 * may use @dev's fields. In particular, get_device()/put_device()
581 * may be used for reference counting of @dev after calling this
582 * function.
583 *
584 * NOTE: Use put_device() to give up your reference instead of freeing
585 * @dev directly once you have called this function.
586 */
587void device_initialize(struct device *dev)
588{
589 dev->kobj.kset = devices_kset;
590 kobject_init(&dev->kobj, &device_ktype);
591 INIT_LIST_HEAD(&dev->dma_pools);
592 mutex_init(&dev->mutex);
593 lockdep_set_novalidate_class(&dev->mutex);
594 spin_lock_init(&dev->devres_lock);
595 INIT_LIST_HEAD(&dev->devres_head);
596 device_pm_init(dev);
597 set_dev_node(dev, -1);
598}
599
600static struct kobject *virtual_device_parent(struct device *dev)
601{
602 static struct kobject *virtual_dir = NULL;
603
604 if (!virtual_dir)
605 virtual_dir = kobject_create_and_add("virtual",
606 &devices_kset->kobj);
607
608 return virtual_dir;
609}
610
611struct class_dir {
612 struct kobject kobj;
613 struct class *class;
614};
615
616#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
617
618static void class_dir_release(struct kobject *kobj)
619{
620 struct class_dir *dir = to_class_dir(kobj);
621 kfree(dir);
622}
623
624static const
625struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
626{
627 struct class_dir *dir = to_class_dir(kobj);
628 return dir->class->ns_type;
629}
630
631static struct kobj_type class_dir_ktype = {
632 .release = class_dir_release,
633 .sysfs_ops = &kobj_sysfs_ops,
634 .child_ns_type = class_dir_child_ns_type
635};
636
637static struct kobject *
638class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
639{
640 struct class_dir *dir;
641 int retval;
642
643 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
644 if (!dir)
645 return NULL;
646
647 dir->class = class;
648 kobject_init(&dir->kobj, &class_dir_ktype);
649
650 dir->kobj.kset = &class->p->glue_dirs;
651
652 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
653 if (retval < 0) {
654 kobject_put(&dir->kobj);
655 return NULL;
656 }
657 return &dir->kobj;
658}
659
660
661static struct kobject *get_device_parent(struct device *dev,
662 struct device *parent)
663{
664 if (dev->class) {
665 static DEFINE_MUTEX(gdp_mutex);
666 struct kobject *kobj = NULL;
667 struct kobject *parent_kobj;
668 struct kobject *k;
669
670#ifdef CONFIG_BLOCK
671 /* block disks show up in /sys/block */
672 if (sysfs_deprecated && dev->class == &block_class) {
673 if (parent && parent->class == &block_class)
674 return &parent->kobj;
675 return &block_class.p->subsys.kobj;
676 }
677#endif
678
679 /*
680 * If we have no parent, we live in "virtual".
681 * Class-devices with a non class-device as parent, live
682 * in a "glue" directory to prevent namespace collisions.
683 */
684 if (parent == NULL)
685 parent_kobj = virtual_device_parent(dev);
686 else if (parent->class && !dev->class->ns_type)
687 return &parent->kobj;
688 else
689 parent_kobj = &parent->kobj;
690
691 mutex_lock(&gdp_mutex);
692
693 /* find our class-directory at the parent and reference it */
694 spin_lock(&dev->class->p->glue_dirs.list_lock);
695 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
696 if (k->parent == parent_kobj) {
697 kobj = kobject_get(k);
698 break;
699 }
700 spin_unlock(&dev->class->p->glue_dirs.list_lock);
701 if (kobj) {
702 mutex_unlock(&gdp_mutex);
703 return kobj;
704 }
705
706 /* or create a new class-directory at the parent device */
707 k = class_dir_create_and_add(dev->class, parent_kobj);
708 /* do not emit an uevent for this simple "glue" directory */
709 mutex_unlock(&gdp_mutex);
710 return k;
711 }
712
713 if (parent)
714 return &parent->kobj;
715 return NULL;
716}
717
718static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
719{
720 /* see if we live in a "glue" directory */
721 if (!glue_dir || !dev->class ||
722 glue_dir->kset != &dev->class->p->glue_dirs)
723 return;
724
725 kobject_put(glue_dir);
726}
727
728static void cleanup_device_parent(struct device *dev)
729{
730 cleanup_glue_dir(dev, dev->kobj.parent);
731}
732
733static void setup_parent(struct device *dev, struct device *parent)
734{
735 struct kobject *kobj;
736 kobj = get_device_parent(dev, parent);
737 if (kobj)
738 dev->kobj.parent = kobj;
739}
740
741static int device_add_class_symlinks(struct device *dev)
742{
743 int error;
744
745 if (!dev->class)
746 return 0;
747
748 error = sysfs_create_link(&dev->kobj,
749 &dev->class->p->subsys.kobj,
750 "subsystem");
751 if (error)
752 goto out;
753
754 if (dev->parent && device_is_not_partition(dev)) {
755 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
756 "device");
757 if (error)
758 goto out_subsys;
759 }
760
761#ifdef CONFIG_BLOCK
762 /* /sys/block has directories and does not need symlinks */
763 if (sysfs_deprecated && dev->class == &block_class)
764 return 0;
765#endif
766
767 /* link in the class directory pointing to the device */
768 error = sysfs_create_link(&dev->class->p->subsys.kobj,
769 &dev->kobj, dev_name(dev));
770 if (error)
771 goto out_device;
772
773 return 0;
774
775out_device:
776 sysfs_remove_link(&dev->kobj, "device");
777
778out_subsys:
779 sysfs_remove_link(&dev->kobj, "subsystem");
780out:
781 return error;
782}
783
784static void device_remove_class_symlinks(struct device *dev)
785{
786 if (!dev->class)
787 return;
788
789 if (dev->parent && device_is_not_partition(dev))
790 sysfs_remove_link(&dev->kobj, "device");
791 sysfs_remove_link(&dev->kobj, "subsystem");
792#ifdef CONFIG_BLOCK
793 if (sysfs_deprecated && dev->class == &block_class)
794 return;
795#endif
796 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
797}
798
799/**
800 * dev_set_name - set a device name
801 * @dev: device
802 * @fmt: format string for the device's name
803 */
804int dev_set_name(struct device *dev, const char *fmt, ...)
805{
806 va_list vargs;
807 int err;
808
809 va_start(vargs, fmt);
810 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
811 va_end(vargs);
812 return err;
813}
814EXPORT_SYMBOL_GPL(dev_set_name);
815
816/**
817 * device_to_dev_kobj - select a /sys/dev/ directory for the device
818 * @dev: device
819 *
820 * By default we select char/ for new entries. Setting class->dev_obj
821 * to NULL prevents an entry from being created. class->dev_kobj must
822 * be set (or cleared) before any devices are registered to the class
823 * otherwise device_create_sys_dev_entry() and
824 * device_remove_sys_dev_entry() will disagree about the the presence
825 * of the link.
826 */
827static struct kobject *device_to_dev_kobj(struct device *dev)
828{
829 struct kobject *kobj;
830
831 if (dev->class)
832 kobj = dev->class->dev_kobj;
833 else
834 kobj = sysfs_dev_char_kobj;
835
836 return kobj;
837}
838
839static int device_create_sys_dev_entry(struct device *dev)
840{
841 struct kobject *kobj = device_to_dev_kobj(dev);
842 int error = 0;
843 char devt_str[15];
844
845 if (kobj) {
846 format_dev_t(devt_str, dev->devt);
847 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
848 }
849
850 return error;
851}
852
853static void device_remove_sys_dev_entry(struct device *dev)
854{
855 struct kobject *kobj = device_to_dev_kobj(dev);
856 char devt_str[15];
857
858 if (kobj) {
859 format_dev_t(devt_str, dev->devt);
860 sysfs_remove_link(kobj, devt_str);
861 }
862}
863
864int device_private_init(struct device *dev)
865{
866 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
867 if (!dev->p)
868 return -ENOMEM;
869 dev->p->device = dev;
870 klist_init(&dev->p->klist_children, klist_children_get,
871 klist_children_put);
872 return 0;
873}
874
875/**
876 * device_add - add device to device hierarchy.
877 * @dev: device.
878 *
879 * This is part 2 of device_register(), though may be called
880 * separately _iff_ device_initialize() has been called separately.
881 *
882 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
883 * to the global and sibling lists for the device, then
884 * adds it to the other relevant subsystems of the driver model.
885 *
886 * NOTE: _Never_ directly free @dev after calling this function, even
887 * if it returned an error! Always use put_device() to give up your
888 * reference instead.
889 */
890int device_add(struct device *dev)
891{
892 struct device *parent = NULL;
893 struct class_interface *class_intf;
894 int error = -EINVAL;
895
896 dev = get_device(dev);
897 if (!dev)
898 goto done;
899
900 if (!dev->p) {
901 error = device_private_init(dev);
902 if (error)
903 goto done;
904 }
905
906 /*
907 * for statically allocated devices, which should all be converted
908 * some day, we need to initialize the name. We prevent reading back
909 * the name, and force the use of dev_name()
910 */
911 if (dev->init_name) {
912 dev_set_name(dev, "%s", dev->init_name);
913 dev->init_name = NULL;
914 }
915
916 if (!dev_name(dev)) {
917 error = -EINVAL;
918 goto name_error;
919 }
920
921 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
922
923 parent = get_device(dev->parent);
924 setup_parent(dev, parent);
925
926 /* use parent numa_node */
927 if (parent)
928 set_dev_node(dev, dev_to_node(parent));
929
930 /* first, register with generic layer. */
931 /* we require the name to be set before, and pass NULL */
932 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
933 if (error)
934 goto Error;
935
936 /* notify platform of device entry */
937 if (platform_notify)
938 platform_notify(dev);
939
940 error = device_create_file(dev, &uevent_attr);
941 if (error)
942 goto attrError;
943
944 if (MAJOR(dev->devt)) {
945 error = device_create_file(dev, &devt_attr);
946 if (error)
947 goto ueventattrError;
948
949 error = device_create_sys_dev_entry(dev);
950 if (error)
951 goto devtattrError;
952
953 devtmpfs_create_node(dev);
954 }
955
956 error = device_add_class_symlinks(dev);
957 if (error)
958 goto SymlinkError;
959 error = device_add_attrs(dev);
960 if (error)
961 goto AttrsError;
962 error = bus_add_device(dev);
963 if (error)
964 goto BusError;
965 error = dpm_sysfs_add(dev);
966 if (error)
967 goto DPMError;
968 device_pm_add(dev);
969
970 /* Notify clients of device addition. This call must come
971 * after dpm_sysf_add() and before kobject_uevent().
972 */
973 if (dev->bus)
974 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
975 BUS_NOTIFY_ADD_DEVICE, dev);
976
977 kobject_uevent(&dev->kobj, KOBJ_ADD);
978 bus_probe_device(dev);
979 if (parent)
980 klist_add_tail(&dev->p->knode_parent,
981 &parent->p->klist_children);
982
983 if (dev->class) {
984 mutex_lock(&dev->class->p->class_mutex);
985 /* tie the class to the device */
986 klist_add_tail(&dev->knode_class,
987 &dev->class->p->klist_devices);
988
989 /* notify any interfaces that the device is here */
990 list_for_each_entry(class_intf,
991 &dev->class->p->class_interfaces, node)
992 if (class_intf->add_dev)
993 class_intf->add_dev(dev, class_intf);
994 mutex_unlock(&dev->class->p->class_mutex);
995 }
996done:
997 put_device(dev);
998 return error;
999 DPMError:
1000 bus_remove_device(dev);
1001 BusError:
1002 device_remove_attrs(dev);
1003 AttrsError:
1004 device_remove_class_symlinks(dev);
1005 SymlinkError:
1006 if (MAJOR(dev->devt))
1007 devtmpfs_delete_node(dev);
1008 if (MAJOR(dev->devt))
1009 device_remove_sys_dev_entry(dev);
1010 devtattrError:
1011 if (MAJOR(dev->devt))
1012 device_remove_file(dev, &devt_attr);
1013 ueventattrError:
1014 device_remove_file(dev, &uevent_attr);
1015 attrError:
1016 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1017 kobject_del(&dev->kobj);
1018 Error:
1019 cleanup_device_parent(dev);
1020 if (parent)
1021 put_device(parent);
1022name_error:
1023 kfree(dev->p);
1024 dev->p = NULL;
1025 goto done;
1026}
1027
1028/**
1029 * device_register - register a device with the system.
1030 * @dev: pointer to the device structure
1031 *
1032 * This happens in two clean steps - initialize the device
1033 * and add it to the system. The two steps can be called
1034 * separately, but this is the easiest and most common.
1035 * I.e. you should only call the two helpers separately if
1036 * have a clearly defined need to use and refcount the device
1037 * before it is added to the hierarchy.
1038 *
1039 * NOTE: _Never_ directly free @dev after calling this function, even
1040 * if it returned an error! Always use put_device() to give up the
1041 * reference initialized in this function instead.
1042 */
1043int device_register(struct device *dev)
1044{
1045 device_initialize(dev);
1046 return device_add(dev);
1047}
1048
1049/**
1050 * get_device - increment reference count for device.
1051 * @dev: device.
1052 *
1053 * This simply forwards the call to kobject_get(), though
1054 * we do take care to provide for the case that we get a NULL
1055 * pointer passed in.
1056 */
1057struct device *get_device(struct device *dev)
1058{
1059 return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
1060}
1061
1062/**
1063 * put_device - decrement reference count.
1064 * @dev: device in question.
1065 */
1066void put_device(struct device *dev)
1067{
1068 /* might_sleep(); */
1069 if (dev)
1070 kobject_put(&dev->kobj);
1071}
1072
1073/**
1074 * device_del - delete device from system.
1075 * @dev: device.
1076 *
1077 * This is the first part of the device unregistration
1078 * sequence. This removes the device from the lists we control
1079 * from here, has it removed from the other driver model
1080 * subsystems it was added to in device_add(), and removes it
1081 * from the kobject hierarchy.
1082 *
1083 * NOTE: this should be called manually _iff_ device_add() was
1084 * also called manually.
1085 */
1086void device_del(struct device *dev)
1087{
1088 struct device *parent = dev->parent;
1089 struct class_interface *class_intf;
1090
1091 /* Notify clients of device removal. This call must come
1092 * before dpm_sysfs_remove().
1093 */
1094 if (dev->bus)
1095 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1096 BUS_NOTIFY_DEL_DEVICE, dev);
1097 device_pm_remove(dev);
1098 dpm_sysfs_remove(dev);
1099 if (parent)
1100 klist_del(&dev->p->knode_parent);
1101 if (MAJOR(dev->devt)) {
1102 devtmpfs_delete_node(dev);
1103 device_remove_sys_dev_entry(dev);
1104 device_remove_file(dev, &devt_attr);
1105 }
1106 if (dev->class) {
1107 device_remove_class_symlinks(dev);
1108
1109 mutex_lock(&dev->class->p->class_mutex);
1110 /* notify any interfaces that the device is now gone */
1111 list_for_each_entry(class_intf,
1112 &dev->class->p->class_interfaces, node)
1113 if (class_intf->remove_dev)
1114 class_intf->remove_dev(dev, class_intf);
1115 /* remove the device from the class list */
1116 klist_del(&dev->knode_class);
1117 mutex_unlock(&dev->class->p->class_mutex);
1118 }
1119 device_remove_file(dev, &uevent_attr);
1120 device_remove_attrs(dev);
1121 bus_remove_device(dev);
1122
1123 /*
1124 * Some platform devices are driven without driver attached
1125 * and managed resources may have been acquired. Make sure
1126 * all resources are released.
1127 */
1128 devres_release_all(dev);
1129
1130 /* Notify the platform of the removal, in case they
1131 * need to do anything...
1132 */
1133 if (platform_notify_remove)
1134 platform_notify_remove(dev);
1135 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1136 cleanup_device_parent(dev);
1137 kobject_del(&dev->kobj);
1138 put_device(parent);
1139}
1140
1141/**
1142 * device_unregister - unregister device from system.
1143 * @dev: device going away.
1144 *
1145 * We do this in two parts, like we do device_register(). First,
1146 * we remove it from all the subsystems with device_del(), then
1147 * we decrement the reference count via put_device(). If that
1148 * is the final reference count, the device will be cleaned up
1149 * via device_release() above. Otherwise, the structure will
1150 * stick around until the final reference to the device is dropped.
1151 */
1152void device_unregister(struct device *dev)
1153{
1154 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1155 device_del(dev);
1156 put_device(dev);
1157}
1158
1159static struct device *next_device(struct klist_iter *i)
1160{
1161 struct klist_node *n = klist_next(i);
1162 struct device *dev = NULL;
1163 struct device_private *p;
1164
1165 if (n) {
1166 p = to_device_private_parent(n);
1167 dev = p->device;
1168 }
1169 return dev;
1170}
1171
1172/**
1173 * device_get_devnode - path of device node file
1174 * @dev: device
1175 * @mode: returned file access mode
1176 * @tmp: possibly allocated string
1177 *
1178 * Return the relative path of a possible device node.
1179 * Non-default names may need to allocate a memory to compose
1180 * a name. This memory is returned in tmp and needs to be
1181 * freed by the caller.
1182 */
1183const char *device_get_devnode(struct device *dev,
1184 mode_t *mode, const char **tmp)
1185{
1186 char *s;
1187
1188 *tmp = NULL;
1189
1190 /* the device type may provide a specific name */
1191 if (dev->type && dev->type->devnode)
1192 *tmp = dev->type->devnode(dev, mode);
1193 if (*tmp)
1194 return *tmp;
1195
1196 /* the class may provide a specific name */
1197 if (dev->class && dev->class->devnode)
1198 *tmp = dev->class->devnode(dev, mode);
1199 if (*tmp)
1200 return *tmp;
1201
1202 /* return name without allocation, tmp == NULL */
1203 if (strchr(dev_name(dev), '!') == NULL)
1204 return dev_name(dev);
1205
1206 /* replace '!' in the name with '/' */
1207 *tmp = kstrdup(dev_name(dev), GFP_KERNEL);
1208 if (!*tmp)
1209 return NULL;
1210 while ((s = strchr(*tmp, '!')))
1211 s[0] = '/';
1212 return *tmp;
1213}
1214
1215/**
1216 * device_for_each_child - device child iterator.
1217 * @parent: parent struct device.
1218 * @data: data for the callback.
1219 * @fn: function to be called for each device.
1220 *
1221 * Iterate over @parent's child devices, and call @fn for each,
1222 * passing it @data.
1223 *
1224 * We check the return of @fn each time. If it returns anything
1225 * other than 0, we break out and return that value.
1226 */
1227int device_for_each_child(struct device *parent, void *data,
1228 int (*fn)(struct device *dev, void *data))
1229{
1230 struct klist_iter i;
1231 struct device *child;
1232 int error = 0;
1233
1234 if (!parent->p)
1235 return 0;
1236
1237 klist_iter_init(&parent->p->klist_children, &i);
1238 while ((child = next_device(&i)) && !error)
1239 error = fn(child, data);
1240 klist_iter_exit(&i);
1241 return error;
1242}
1243
1244/**
1245 * device_find_child - device iterator for locating a particular device.
1246 * @parent: parent struct device
1247 * @data: Data to pass to match function
1248 * @match: Callback function to check device
1249 *
1250 * This is similar to the device_for_each_child() function above, but it
1251 * returns a reference to a device that is 'found' for later use, as
1252 * determined by the @match callback.
1253 *
1254 * The callback should return 0 if the device doesn't match and non-zero
1255 * if it does. If the callback returns non-zero and a reference to the
1256 * current device can be obtained, this function will return to the caller
1257 * and not iterate over any more devices.
1258 */
1259struct device *device_find_child(struct device *parent, void *data,
1260 int (*match)(struct device *dev, void *data))
1261{
1262 struct klist_iter i;
1263 struct device *child;
1264
1265 if (!parent)
1266 return NULL;
1267
1268 klist_iter_init(&parent->p->klist_children, &i);
1269 while ((child = next_device(&i)))
1270 if (match(child, data) && get_device(child))
1271 break;
1272 klist_iter_exit(&i);
1273 return child;
1274}
1275
1276int __init devices_init(void)
1277{
1278 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
1279 if (!devices_kset)
1280 return -ENOMEM;
1281 dev_kobj = kobject_create_and_add("dev", NULL);
1282 if (!dev_kobj)
1283 goto dev_kobj_err;
1284 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
1285 if (!sysfs_dev_block_kobj)
1286 goto block_kobj_err;
1287 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
1288 if (!sysfs_dev_char_kobj)
1289 goto char_kobj_err;
1290
1291 return 0;
1292
1293 char_kobj_err:
1294 kobject_put(sysfs_dev_block_kobj);
1295 block_kobj_err:
1296 kobject_put(dev_kobj);
1297 dev_kobj_err:
1298 kset_unregister(devices_kset);
1299 return -ENOMEM;
1300}
1301
1302EXPORT_SYMBOL_GPL(device_for_each_child);
1303EXPORT_SYMBOL_GPL(device_find_child);
1304
1305EXPORT_SYMBOL_GPL(device_initialize);
1306EXPORT_SYMBOL_GPL(device_add);
1307EXPORT_SYMBOL_GPL(device_register);
1308
1309EXPORT_SYMBOL_GPL(device_del);
1310EXPORT_SYMBOL_GPL(device_unregister);
1311EXPORT_SYMBOL_GPL(get_device);
1312EXPORT_SYMBOL_GPL(put_device);
1313
1314EXPORT_SYMBOL_GPL(device_create_file);
1315EXPORT_SYMBOL_GPL(device_remove_file);
1316
1317struct root_device {
1318 struct device dev;
1319 struct module *owner;
1320};
1321
1322inline struct root_device *to_root_device(struct device *d)
1323{
1324 return container_of(d, struct root_device, dev);
1325}
1326
1327static void root_device_release(struct device *dev)
1328{
1329 kfree(to_root_device(dev));
1330}
1331
1332/**
1333 * __root_device_register - allocate and register a root device
1334 * @name: root device name
1335 * @owner: owner module of the root device, usually THIS_MODULE
1336 *
1337 * This function allocates a root device and registers it
1338 * using device_register(). In order to free the returned
1339 * device, use root_device_unregister().
1340 *
1341 * Root devices are dummy devices which allow other devices
1342 * to be grouped under /sys/devices. Use this function to
1343 * allocate a root device and then use it as the parent of
1344 * any device which should appear under /sys/devices/{name}
1345 *
1346 * The /sys/devices/{name} directory will also contain a
1347 * 'module' symlink which points to the @owner directory
1348 * in sysfs.
1349 *
1350 * Returns &struct device pointer on success, or ERR_PTR() on error.
1351 *
1352 * Note: You probably want to use root_device_register().
1353 */
1354struct device *__root_device_register(const char *name, struct module *owner)
1355{
1356 struct root_device *root;
1357 int err = -ENOMEM;
1358
1359 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
1360 if (!root)
1361 return ERR_PTR(err);
1362
1363 err = dev_set_name(&root->dev, "%s", name);
1364 if (err) {
1365 kfree(root);
1366 return ERR_PTR(err);
1367 }
1368
1369 root->dev.release = root_device_release;
1370
1371 err = device_register(&root->dev);
1372 if (err) {
1373 put_device(&root->dev);
1374 return ERR_PTR(err);
1375 }
1376
1377#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
1378 if (owner) {
1379 struct module_kobject *mk = &owner->mkobj;
1380
1381 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
1382 if (err) {
1383 device_unregister(&root->dev);
1384 return ERR_PTR(err);
1385 }
1386 root->owner = owner;
1387 }
1388#endif
1389
1390 return &root->dev;
1391}
1392EXPORT_SYMBOL_GPL(__root_device_register);
1393
1394/**
1395 * root_device_unregister - unregister and free a root device
1396 * @dev: device going away
1397 *
1398 * This function unregisters and cleans up a device that was created by
1399 * root_device_register().
1400 */
1401void root_device_unregister(struct device *dev)
1402{
1403 struct root_device *root = to_root_device(dev);
1404
1405 if (root->owner)
1406 sysfs_remove_link(&root->dev.kobj, "module");
1407
1408 device_unregister(dev);
1409}
1410EXPORT_SYMBOL_GPL(root_device_unregister);
1411
1412
1413static void device_create_release(struct device *dev)
1414{
1415 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1416 kfree(dev);
1417}
1418
1419/**
1420 * device_create_vargs - creates a device and registers it with sysfs
1421 * @class: pointer to the struct class that this device should be registered to
1422 * @parent: pointer to the parent struct device of this new device, if any
1423 * @devt: the dev_t for the char device to be added
1424 * @drvdata: the data to be added to the device for callbacks
1425 * @fmt: string for the device's name
1426 * @args: va_list for the device's name
1427 *
1428 * This function can be used by char device classes. A struct device
1429 * will be created in sysfs, registered to the specified class.
1430 *
1431 * A "dev" file will be created, showing the dev_t for the device, if
1432 * the dev_t is not 0,0.
1433 * If a pointer to a parent struct device is passed in, the newly created
1434 * struct device will be a child of that device in sysfs.
1435 * The pointer to the struct device will be returned from the call.
1436 * Any further sysfs files that might be required can be created using this
1437 * pointer.
1438 *
1439 * Returns &struct device pointer on success, or ERR_PTR() on error.
1440 *
1441 * Note: the struct class passed to this function must have previously
1442 * been created with a call to class_create().
1443 */
1444struct device *device_create_vargs(struct class *class, struct device *parent,
1445 dev_t devt, void *drvdata, const char *fmt,
1446 va_list args)
1447{
1448 struct device *dev = NULL;
1449 int retval = -ENODEV;
1450
1451 if (class == NULL || IS_ERR(class))
1452 goto error;
1453
1454 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1455 if (!dev) {
1456 retval = -ENOMEM;
1457 goto error;
1458 }
1459
1460 dev->devt = devt;
1461 dev->class = class;
1462 dev->parent = parent;
1463 dev->release = device_create_release;
1464 dev_set_drvdata(dev, drvdata);
1465
1466 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
1467 if (retval)
1468 goto error;
1469
1470 retval = device_register(dev);
1471 if (retval)
1472 goto error;
1473
1474 return dev;
1475
1476error:
1477 put_device(dev);
1478 return ERR_PTR(retval);
1479}
1480EXPORT_SYMBOL_GPL(device_create_vargs);
1481
1482/**
1483 * device_create - creates a device and registers it with sysfs
1484 * @class: pointer to the struct class that this device should be registered to
1485 * @parent: pointer to the parent struct device of this new device, if any
1486 * @devt: the dev_t for the char device to be added
1487 * @drvdata: the data to be added to the device for callbacks
1488 * @fmt: string for the device's name
1489 *
1490 * This function can be used by char device classes. A struct device
1491 * will be created in sysfs, registered to the specified class.
1492 *
1493 * A "dev" file will be created, showing the dev_t for the device, if
1494 * the dev_t is not 0,0.
1495 * If a pointer to a parent struct device is passed in, the newly created
1496 * struct device will be a child of that device in sysfs.
1497 * The pointer to the struct device will be returned from the call.
1498 * Any further sysfs files that might be required can be created using this
1499 * pointer.
1500 *
1501 * Returns &struct device pointer on success, or ERR_PTR() on error.
1502 *
1503 * Note: the struct class passed to this function must have previously
1504 * been created with a call to class_create().
1505 */
1506struct device *device_create(struct class *class, struct device *parent,
1507 dev_t devt, void *drvdata, const char *fmt, ...)
1508{
1509 va_list vargs;
1510 struct device *dev;
1511
1512 va_start(vargs, fmt);
1513 dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
1514 va_end(vargs);
1515 return dev;
1516}
1517EXPORT_SYMBOL_GPL(device_create);
1518
1519static int __match_devt(struct device *dev, void *data)
1520{
1521 dev_t *devt = data;
1522
1523 return dev->devt == *devt;
1524}
1525
1526/**
1527 * device_destroy - removes a device that was created with device_create()
1528 * @class: pointer to the struct class that this device was registered with
1529 * @devt: the dev_t of the device that was previously registered
1530 *
1531 * This call unregisters and cleans up a device that was created with a
1532 * call to device_create().
1533 */
1534void device_destroy(struct class *class, dev_t devt)
1535{
1536 struct device *dev;
1537
1538 dev = class_find_device(class, NULL, &devt, __match_devt);
1539 if (dev) {
1540 put_device(dev);
1541 device_unregister(dev);
1542 }
1543}
1544EXPORT_SYMBOL_GPL(device_destroy);
1545
1546/**
1547 * device_rename - renames a device
1548 * @dev: the pointer to the struct device to be renamed
1549 * @new_name: the new name of the device
1550 *
1551 * It is the responsibility of the caller to provide mutual
1552 * exclusion between two different calls of device_rename
1553 * on the same device to ensure that new_name is valid and
1554 * won't conflict with other devices.
1555 *
1556 * Note: Don't call this function. Currently, the networking layer calls this
1557 * function, but that will change. The following text from Kay Sievers offers
1558 * some insight:
1559 *
1560 * Renaming devices is racy at many levels, symlinks and other stuff are not
1561 * replaced atomically, and you get a "move" uevent, but it's not easy to
1562 * connect the event to the old and new device. Device nodes are not renamed at
1563 * all, there isn't even support for that in the kernel now.
1564 *
1565 * In the meantime, during renaming, your target name might be taken by another
1566 * driver, creating conflicts. Or the old name is taken directly after you
1567 * renamed it -- then you get events for the same DEVPATH, before you even see
1568 * the "move" event. It's just a mess, and nothing new should ever rely on
1569 * kernel device renaming. Besides that, it's not even implemented now for
1570 * other things than (driver-core wise very simple) network devices.
1571 *
1572 * We are currently about to change network renaming in udev to completely
1573 * disallow renaming of devices in the same namespace as the kernel uses,
1574 * because we can't solve the problems properly, that arise with swapping names
1575 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
1576 * be allowed to some other name than eth[0-9]*, for the aforementioned
1577 * reasons.
1578 *
1579 * Make up a "real" name in the driver before you register anything, or add
1580 * some other attributes for userspace to find the device, or use udev to add
1581 * symlinks -- but never rename kernel devices later, it's a complete mess. We
1582 * don't even want to get into that and try to implement the missing pieces in
1583 * the core. We really have other pieces to fix in the driver core mess. :)
1584 */
1585int device_rename(struct device *dev, const char *new_name)
1586{
1587 char *old_class_name = NULL;
1588 char *new_class_name = NULL;
1589 char *old_device_name = NULL;
1590 int error;
1591
1592 dev = get_device(dev);
1593 if (!dev)
1594 return -EINVAL;
1595
1596 pr_debug("device: '%s': %s: renaming to '%s'\n", dev_name(dev),
1597 __func__, new_name);
1598
1599 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
1600 if (!old_device_name) {
1601 error = -ENOMEM;
1602 goto out;
1603 }
1604
1605 if (dev->class) {
1606 error = sysfs_rename_link(&dev->class->p->subsys.kobj,
1607 &dev->kobj, old_device_name, new_name);
1608 if (error)
1609 goto out;
1610 }
1611
1612 error = kobject_rename(&dev->kobj, new_name);
1613 if (error)
1614 goto out;
1615
1616out:
1617 put_device(dev);
1618
1619 kfree(new_class_name);
1620 kfree(old_class_name);
1621 kfree(old_device_name);
1622
1623 return error;
1624}
1625EXPORT_SYMBOL_GPL(device_rename);
1626
1627static int device_move_class_links(struct device *dev,
1628 struct device *old_parent,
1629 struct device *new_parent)
1630{
1631 int error = 0;
1632
1633 if (old_parent)
1634 sysfs_remove_link(&dev->kobj, "device");
1635 if (new_parent)
1636 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1637 "device");
1638 return error;
1639}
1640
1641/**
1642 * device_move - moves a device to a new parent
1643 * @dev: the pointer to the struct device to be moved
1644 * @new_parent: the new parent of the device (can by NULL)
1645 * @dpm_order: how to reorder the dpm_list
1646 */
1647int device_move(struct device *dev, struct device *new_parent,
1648 enum dpm_order dpm_order)
1649{
1650 int error;
1651 struct device *old_parent;
1652 struct kobject *new_parent_kobj;
1653
1654 dev = get_device(dev);
1655 if (!dev)
1656 return -EINVAL;
1657
1658 device_pm_lock();
1659 new_parent = get_device(new_parent);
1660 new_parent_kobj = get_device_parent(dev, new_parent);
1661
1662 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
1663 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
1664 error = kobject_move(&dev->kobj, new_parent_kobj);
1665 if (error) {
1666 cleanup_glue_dir(dev, new_parent_kobj);
1667 put_device(new_parent);
1668 goto out;
1669 }
1670 old_parent = dev->parent;
1671 dev->parent = new_parent;
1672 if (old_parent)
1673 klist_remove(&dev->p->knode_parent);
1674 if (new_parent) {
1675 klist_add_tail(&dev->p->knode_parent,
1676 &new_parent->p->klist_children);
1677 set_dev_node(dev, dev_to_node(new_parent));
1678 }
1679
1680 if (!dev->class)
1681 goto out_put;
1682 error = device_move_class_links(dev, old_parent, new_parent);
1683 if (error) {
1684 /* We ignore errors on cleanup since we're hosed anyway... */
1685 device_move_class_links(dev, new_parent, old_parent);
1686 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
1687 if (new_parent)
1688 klist_remove(&dev->p->knode_parent);
1689 dev->parent = old_parent;
1690 if (old_parent) {
1691 klist_add_tail(&dev->p->knode_parent,
1692 &old_parent->p->klist_children);
1693 set_dev_node(dev, dev_to_node(old_parent));
1694 }
1695 }
1696 cleanup_glue_dir(dev, new_parent_kobj);
1697 put_device(new_parent);
1698 goto out;
1699 }
1700 switch (dpm_order) {
1701 case DPM_ORDER_NONE:
1702 break;
1703 case DPM_ORDER_DEV_AFTER_PARENT:
1704 device_pm_move_after(dev, new_parent);
1705 break;
1706 case DPM_ORDER_PARENT_BEFORE_DEV:
1707 device_pm_move_before(new_parent, dev);
1708 break;
1709 case DPM_ORDER_DEV_LAST:
1710 device_pm_move_last(dev);
1711 break;
1712 }
1713out_put:
1714 put_device(old_parent);
1715out:
1716 device_pm_unlock();
1717 put_device(dev);
1718 return error;
1719}
1720EXPORT_SYMBOL_GPL(device_move);
1721
1722/**
1723 * device_shutdown - call ->shutdown() on each device to shutdown.
1724 */
1725void device_shutdown(void)
1726{
1727 struct device *dev;
1728
1729 spin_lock(&devices_kset->list_lock);
1730 /*
1731 * Walk the devices list backward, shutting down each in turn.
1732 * Beware that device unplug events may also start pulling
1733 * devices offline, even as the system is shutting down.
1734 */
1735 while (!list_empty(&devices_kset->list)) {
1736 dev = list_entry(devices_kset->list.prev, struct device,
1737 kobj.entry);
1738 get_device(dev);
1739 /*
1740 * Make sure the device is off the kset list, in the
1741 * event that dev->*->shutdown() doesn't remove it.
1742 */
1743 list_del_init(&dev->kobj.entry);
1744 spin_unlock(&devices_kset->list_lock);
1745
1746 if (dev->bus && dev->bus->shutdown) {
1747 dev_dbg(dev, "shutdown\n");
1748 dev->bus->shutdown(dev);
1749 } else if (dev->driver && dev->driver->shutdown) {
1750 dev_dbg(dev, "shutdown\n");
1751 dev->driver->shutdown(dev);
1752 }
1753 put_device(dev);
1754
1755 spin_lock(&devices_kset->list_lock);
1756 }
1757 spin_unlock(&devices_kset->list_lock);
1758 async_synchronize_full();
1759}
1760
1761/*
1762 * Device logging functions
1763 */
1764
1765#ifdef CONFIG_PRINTK
1766
1767static int __dev_printk(const char *level, const struct device *dev,
1768 struct va_format *vaf)
1769{
1770 if (!dev)
1771 return printk("%s(NULL device *): %pV", level, vaf);
1772
1773 return printk("%s%s %s: %pV",
1774 level, dev_driver_string(dev), dev_name(dev), vaf);
1775}
1776
1777int dev_printk(const char *level, const struct device *dev,
1778 const char *fmt, ...)
1779{
1780 struct va_format vaf;
1781 va_list args;
1782 int r;
1783
1784 va_start(args, fmt);
1785
1786 vaf.fmt = fmt;
1787 vaf.va = &args;
1788
1789 r = __dev_printk(level, dev, &vaf);
1790 va_end(args);
1791
1792 return r;
1793}
1794EXPORT_SYMBOL(dev_printk);
1795
1796#define define_dev_printk_level(func, kern_level) \
1797int func(const struct device *dev, const char *fmt, ...) \
1798{ \
1799 struct va_format vaf; \
1800 va_list args; \
1801 int r; \
1802 \
1803 va_start(args, fmt); \
1804 \
1805 vaf.fmt = fmt; \
1806 vaf.va = &args; \
1807 \
1808 r = __dev_printk(kern_level, dev, &vaf); \
1809 va_end(args); \
1810 \
1811 return r; \
1812} \
1813EXPORT_SYMBOL(func);
1814
1815define_dev_printk_level(dev_emerg, KERN_EMERG);
1816define_dev_printk_level(dev_alert, KERN_ALERT);
1817define_dev_printk_level(dev_crit, KERN_CRIT);
1818define_dev_printk_level(dev_err, KERN_ERR);
1819define_dev_printk_level(dev_warn, KERN_WARNING);
1820define_dev_printk_level(dev_notice, KERN_NOTICE);
1821define_dev_printk_level(_dev_info, KERN_INFO);
1822
1823#endif
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * drivers/base/core.c - core driver model code (device registration, etc)
4 *
5 * Copyright (c) 2002-3 Patrick Mochel
6 * Copyright (c) 2002-3 Open Source Development Labs
7 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
8 * Copyright (c) 2006 Novell, Inc.
9 */
10
11#include <linux/acpi.h>
12#include <linux/blkdev.h>
13#include <linux/cleanup.h>
14#include <linux/cpufreq.h>
15#include <linux/device.h>
16#include <linux/dma-map-ops.h> /* for dma_default_coherent */
17#include <linux/err.h>
18#include <linux/fwnode.h>
19#include <linux/init.h>
20#include <linux/kdev_t.h>
21#include <linux/kstrtox.h>
22#include <linux/module.h>
23#include <linux/mutex.h>
24#include <linux/netdevice.h>
25#include <linux/notifier.h>
26#include <linux/of.h>
27#include <linux/of_device.h>
28#include <linux/pm_runtime.h>
29#include <linux/sched/mm.h>
30#include <linux/sched/signal.h>
31#include <linux/slab.h>
32#include <linux/string_helpers.h>
33#include <linux/swiotlb.h>
34#include <linux/sysfs.h>
35
36#include "base.h"
37#include "physical_location.h"
38#include "power/power.h"
39
40/* Device links support. */
41static LIST_HEAD(deferred_sync);
42static unsigned int defer_sync_state_count = 1;
43static DEFINE_MUTEX(fwnode_link_lock);
44static bool fw_devlink_is_permissive(void);
45static void __fw_devlink_link_to_consumers(struct device *dev);
46static bool fw_devlink_drv_reg_done;
47static bool fw_devlink_best_effort;
48static struct workqueue_struct *device_link_wq;
49
50/**
51 * __fwnode_link_add - Create a link between two fwnode_handles.
52 * @con: Consumer end of the link.
53 * @sup: Supplier end of the link.
54 * @flags: Link flags.
55 *
56 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
57 * represents the detail that the firmware lists @sup fwnode as supplying a
58 * resource to @con.
59 *
60 * The driver core will use the fwnode link to create a device link between the
61 * two device objects corresponding to @con and @sup when they are created. The
62 * driver core will automatically delete the fwnode link between @con and @sup
63 * after doing that.
64 *
65 * Attempts to create duplicate links between the same pair of fwnode handles
66 * are ignored and there is no reference counting.
67 */
68static int __fwnode_link_add(struct fwnode_handle *con,
69 struct fwnode_handle *sup, u8 flags)
70{
71 struct fwnode_link *link;
72
73 list_for_each_entry(link, &sup->consumers, s_hook)
74 if (link->consumer == con) {
75 link->flags |= flags;
76 return 0;
77 }
78
79 link = kzalloc(sizeof(*link), GFP_KERNEL);
80 if (!link)
81 return -ENOMEM;
82
83 link->supplier = sup;
84 INIT_LIST_HEAD(&link->s_hook);
85 link->consumer = con;
86 INIT_LIST_HEAD(&link->c_hook);
87 link->flags = flags;
88
89 list_add(&link->s_hook, &sup->consumers);
90 list_add(&link->c_hook, &con->suppliers);
91 pr_debug("%pfwf Linked as a fwnode consumer to %pfwf\n",
92 con, sup);
93
94 return 0;
95}
96
97int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup,
98 u8 flags)
99{
100 guard(mutex)(&fwnode_link_lock);
101
102 return __fwnode_link_add(con, sup, flags);
103}
104
105/**
106 * __fwnode_link_del - Delete a link between two fwnode_handles.
107 * @link: the fwnode_link to be deleted
108 *
109 * The fwnode_link_lock needs to be held when this function is called.
110 */
111static void __fwnode_link_del(struct fwnode_link *link)
112{
113 pr_debug("%pfwf Dropping the fwnode link to %pfwf\n",
114 link->consumer, link->supplier);
115 list_del(&link->s_hook);
116 list_del(&link->c_hook);
117 kfree(link);
118}
119
120/**
121 * __fwnode_link_cycle - Mark a fwnode link as being part of a cycle.
122 * @link: the fwnode_link to be marked
123 *
124 * The fwnode_link_lock needs to be held when this function is called.
125 */
126static void __fwnode_link_cycle(struct fwnode_link *link)
127{
128 pr_debug("%pfwf: cycle: depends on %pfwf\n",
129 link->consumer, link->supplier);
130 link->flags |= FWLINK_FLAG_CYCLE;
131}
132
133/**
134 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
135 * @fwnode: fwnode whose supplier links need to be deleted
136 *
137 * Deletes all supplier links connecting directly to @fwnode.
138 */
139static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
140{
141 struct fwnode_link *link, *tmp;
142
143 guard(mutex)(&fwnode_link_lock);
144
145 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook)
146 __fwnode_link_del(link);
147}
148
149/**
150 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle.
151 * @fwnode: fwnode whose consumer links need to be deleted
152 *
153 * Deletes all consumer links connecting directly to @fwnode.
154 */
155static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
156{
157 struct fwnode_link *link, *tmp;
158
159 guard(mutex)(&fwnode_link_lock);
160
161 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook)
162 __fwnode_link_del(link);
163}
164
165/**
166 * fwnode_links_purge - Delete all links connected to a fwnode_handle.
167 * @fwnode: fwnode whose links needs to be deleted
168 *
169 * Deletes all links connecting directly to a fwnode.
170 */
171void fwnode_links_purge(struct fwnode_handle *fwnode)
172{
173 fwnode_links_purge_suppliers(fwnode);
174 fwnode_links_purge_consumers(fwnode);
175}
176
177void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
178{
179 struct fwnode_handle *child;
180
181 /* Don't purge consumer links of an added child */
182 if (fwnode->dev)
183 return;
184
185 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
186 fwnode_links_purge_consumers(fwnode);
187
188 fwnode_for_each_available_child_node(fwnode, child)
189 fw_devlink_purge_absent_suppliers(child);
190}
191EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
192
193/**
194 * __fwnode_links_move_consumers - Move consumer from @from to @to fwnode_handle
195 * @from: move consumers away from this fwnode
196 * @to: move consumers to this fwnode
197 *
198 * Move all consumer links from @from fwnode to @to fwnode.
199 */
200static void __fwnode_links_move_consumers(struct fwnode_handle *from,
201 struct fwnode_handle *to)
202{
203 struct fwnode_link *link, *tmp;
204
205 list_for_each_entry_safe(link, tmp, &from->consumers, s_hook) {
206 __fwnode_link_add(link->consumer, to, link->flags);
207 __fwnode_link_del(link);
208 }
209}
210
211/**
212 * __fw_devlink_pickup_dangling_consumers - Pick up dangling consumers
213 * @fwnode: fwnode from which to pick up dangling consumers
214 * @new_sup: fwnode of new supplier
215 *
216 * If the @fwnode has a corresponding struct device and the device supports
217 * probing (that is, added to a bus), then we want to let fw_devlink create
218 * MANAGED device links to this device, so leave @fwnode and its descendant's
219 * fwnode links alone.
220 *
221 * Otherwise, move its consumers to the new supplier @new_sup.
222 */
223static void __fw_devlink_pickup_dangling_consumers(struct fwnode_handle *fwnode,
224 struct fwnode_handle *new_sup)
225{
226 struct fwnode_handle *child;
227
228 if (fwnode->dev && fwnode->dev->bus)
229 return;
230
231 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
232 __fwnode_links_move_consumers(fwnode, new_sup);
233
234 fwnode_for_each_available_child_node(fwnode, child)
235 __fw_devlink_pickup_dangling_consumers(child, new_sup);
236}
237
238static DEFINE_MUTEX(device_links_lock);
239DEFINE_STATIC_SRCU(device_links_srcu);
240
241static inline void device_links_write_lock(void)
242{
243 mutex_lock(&device_links_lock);
244}
245
246static inline void device_links_write_unlock(void)
247{
248 mutex_unlock(&device_links_lock);
249}
250
251int device_links_read_lock(void) __acquires(&device_links_srcu)
252{
253 return srcu_read_lock(&device_links_srcu);
254}
255
256void device_links_read_unlock(int idx) __releases(&device_links_srcu)
257{
258 srcu_read_unlock(&device_links_srcu, idx);
259}
260
261int device_links_read_lock_held(void)
262{
263 return srcu_read_lock_held(&device_links_srcu);
264}
265
266static void device_link_synchronize_removal(void)
267{
268 synchronize_srcu(&device_links_srcu);
269}
270
271static void device_link_remove_from_lists(struct device_link *link)
272{
273 list_del_rcu(&link->s_node);
274 list_del_rcu(&link->c_node);
275}
276
277static bool device_is_ancestor(struct device *dev, struct device *target)
278{
279 while (target->parent) {
280 target = target->parent;
281 if (dev == target)
282 return true;
283 }
284 return false;
285}
286
287#define DL_MARKER_FLAGS (DL_FLAG_INFERRED | \
288 DL_FLAG_CYCLE | \
289 DL_FLAG_MANAGED)
290static inline bool device_link_flag_is_sync_state_only(u32 flags)
291{
292 return (flags & ~DL_MARKER_FLAGS) == DL_FLAG_SYNC_STATE_ONLY;
293}
294
295/**
296 * device_is_dependent - Check if one device depends on another one
297 * @dev: Device to check dependencies for.
298 * @target: Device to check against.
299 *
300 * Check if @target depends on @dev or any device dependent on it (its child or
301 * its consumer etc). Return 1 if that is the case or 0 otherwise.
302 */
303static int device_is_dependent(struct device *dev, void *target)
304{
305 struct device_link *link;
306 int ret;
307
308 /*
309 * The "ancestors" check is needed to catch the case when the target
310 * device has not been completely initialized yet and it is still
311 * missing from the list of children of its parent device.
312 */
313 if (dev == target || device_is_ancestor(dev, target))
314 return 1;
315
316 ret = device_for_each_child(dev, target, device_is_dependent);
317 if (ret)
318 return ret;
319
320 list_for_each_entry(link, &dev->links.consumers, s_node) {
321 if (device_link_flag_is_sync_state_only(link->flags))
322 continue;
323
324 if (link->consumer == target)
325 return 1;
326
327 ret = device_is_dependent(link->consumer, target);
328 if (ret)
329 break;
330 }
331 return ret;
332}
333
334static void device_link_init_status(struct device_link *link,
335 struct device *consumer,
336 struct device *supplier)
337{
338 switch (supplier->links.status) {
339 case DL_DEV_PROBING:
340 switch (consumer->links.status) {
341 case DL_DEV_PROBING:
342 /*
343 * A consumer driver can create a link to a supplier
344 * that has not completed its probing yet as long as it
345 * knows that the supplier is already functional (for
346 * example, it has just acquired some resources from the
347 * supplier).
348 */
349 link->status = DL_STATE_CONSUMER_PROBE;
350 break;
351 default:
352 link->status = DL_STATE_DORMANT;
353 break;
354 }
355 break;
356 case DL_DEV_DRIVER_BOUND:
357 switch (consumer->links.status) {
358 case DL_DEV_PROBING:
359 link->status = DL_STATE_CONSUMER_PROBE;
360 break;
361 case DL_DEV_DRIVER_BOUND:
362 link->status = DL_STATE_ACTIVE;
363 break;
364 default:
365 link->status = DL_STATE_AVAILABLE;
366 break;
367 }
368 break;
369 case DL_DEV_UNBINDING:
370 link->status = DL_STATE_SUPPLIER_UNBIND;
371 break;
372 default:
373 link->status = DL_STATE_DORMANT;
374 break;
375 }
376}
377
378static int device_reorder_to_tail(struct device *dev, void *not_used)
379{
380 struct device_link *link;
381
382 /*
383 * Devices that have not been registered yet will be put to the ends
384 * of the lists during the registration, so skip them here.
385 */
386 if (device_is_registered(dev))
387 devices_kset_move_last(dev);
388
389 if (device_pm_initialized(dev))
390 device_pm_move_last(dev);
391
392 device_for_each_child(dev, NULL, device_reorder_to_tail);
393 list_for_each_entry(link, &dev->links.consumers, s_node) {
394 if (device_link_flag_is_sync_state_only(link->flags))
395 continue;
396 device_reorder_to_tail(link->consumer, NULL);
397 }
398
399 return 0;
400}
401
402/**
403 * device_pm_move_to_tail - Move set of devices to the end of device lists
404 * @dev: Device to move
405 *
406 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
407 *
408 * It moves the @dev along with all of its children and all of its consumers
409 * to the ends of the device_kset and dpm_list, recursively.
410 */
411void device_pm_move_to_tail(struct device *dev)
412{
413 int idx;
414
415 idx = device_links_read_lock();
416 device_pm_lock();
417 device_reorder_to_tail(dev, NULL);
418 device_pm_unlock();
419 device_links_read_unlock(idx);
420}
421
422#define to_devlink(dev) container_of((dev), struct device_link, link_dev)
423
424static ssize_t status_show(struct device *dev,
425 struct device_attribute *attr, char *buf)
426{
427 const char *output;
428
429 switch (to_devlink(dev)->status) {
430 case DL_STATE_NONE:
431 output = "not tracked";
432 break;
433 case DL_STATE_DORMANT:
434 output = "dormant";
435 break;
436 case DL_STATE_AVAILABLE:
437 output = "available";
438 break;
439 case DL_STATE_CONSUMER_PROBE:
440 output = "consumer probing";
441 break;
442 case DL_STATE_ACTIVE:
443 output = "active";
444 break;
445 case DL_STATE_SUPPLIER_UNBIND:
446 output = "supplier unbinding";
447 break;
448 default:
449 output = "unknown";
450 break;
451 }
452
453 return sysfs_emit(buf, "%s\n", output);
454}
455static DEVICE_ATTR_RO(status);
456
457static ssize_t auto_remove_on_show(struct device *dev,
458 struct device_attribute *attr, char *buf)
459{
460 struct device_link *link = to_devlink(dev);
461 const char *output;
462
463 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
464 output = "supplier unbind";
465 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
466 output = "consumer unbind";
467 else
468 output = "never";
469
470 return sysfs_emit(buf, "%s\n", output);
471}
472static DEVICE_ATTR_RO(auto_remove_on);
473
474static ssize_t runtime_pm_show(struct device *dev,
475 struct device_attribute *attr, char *buf)
476{
477 struct device_link *link = to_devlink(dev);
478
479 return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
480}
481static DEVICE_ATTR_RO(runtime_pm);
482
483static ssize_t sync_state_only_show(struct device *dev,
484 struct device_attribute *attr, char *buf)
485{
486 struct device_link *link = to_devlink(dev);
487
488 return sysfs_emit(buf, "%d\n",
489 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
490}
491static DEVICE_ATTR_RO(sync_state_only);
492
493static struct attribute *devlink_attrs[] = {
494 &dev_attr_status.attr,
495 &dev_attr_auto_remove_on.attr,
496 &dev_attr_runtime_pm.attr,
497 &dev_attr_sync_state_only.attr,
498 NULL,
499};
500ATTRIBUTE_GROUPS(devlink);
501
502static void device_link_release_fn(struct work_struct *work)
503{
504 struct device_link *link = container_of(work, struct device_link, rm_work);
505
506 /* Ensure that all references to the link object have been dropped. */
507 device_link_synchronize_removal();
508
509 pm_runtime_release_supplier(link);
510 /*
511 * If supplier_preactivated is set, the link has been dropped between
512 * the pm_runtime_get_suppliers() and pm_runtime_put_suppliers() calls
513 * in __driver_probe_device(). In that case, drop the supplier's
514 * PM-runtime usage counter to remove the reference taken by
515 * pm_runtime_get_suppliers().
516 */
517 if (link->supplier_preactivated)
518 pm_runtime_put_noidle(link->supplier);
519
520 pm_request_idle(link->supplier);
521
522 put_device(link->consumer);
523 put_device(link->supplier);
524 kfree(link);
525}
526
527static void devlink_dev_release(struct device *dev)
528{
529 struct device_link *link = to_devlink(dev);
530
531 INIT_WORK(&link->rm_work, device_link_release_fn);
532 /*
533 * It may take a while to complete this work because of the SRCU
534 * synchronization in device_link_release_fn() and if the consumer or
535 * supplier devices get deleted when it runs, so put it into the
536 * dedicated workqueue.
537 */
538 queue_work(device_link_wq, &link->rm_work);
539}
540
541/**
542 * device_link_wait_removal - Wait for ongoing devlink removal jobs to terminate
543 */
544void device_link_wait_removal(void)
545{
546 /*
547 * devlink removal jobs are queued in the dedicated work queue.
548 * To be sure that all removal jobs are terminated, ensure that any
549 * scheduled work has run to completion.
550 */
551 flush_workqueue(device_link_wq);
552}
553EXPORT_SYMBOL_GPL(device_link_wait_removal);
554
555static const struct class devlink_class = {
556 .name = "devlink",
557 .dev_groups = devlink_groups,
558 .dev_release = devlink_dev_release,
559};
560
561static int devlink_add_symlinks(struct device *dev)
562{
563 char *buf_con __free(kfree) = NULL, *buf_sup __free(kfree) = NULL;
564 int ret;
565 struct device_link *link = to_devlink(dev);
566 struct device *sup = link->supplier;
567 struct device *con = link->consumer;
568
569 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
570 if (ret)
571 goto out;
572
573 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
574 if (ret)
575 goto err_con;
576
577 buf_con = kasprintf(GFP_KERNEL, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
578 if (!buf_con) {
579 ret = -ENOMEM;
580 goto err_con_dev;
581 }
582
583 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf_con);
584 if (ret)
585 goto err_con_dev;
586
587 buf_sup = kasprintf(GFP_KERNEL, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
588 if (!buf_sup) {
589 ret = -ENOMEM;
590 goto err_sup_dev;
591 }
592
593 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf_sup);
594 if (ret)
595 goto err_sup_dev;
596
597 goto out;
598
599err_sup_dev:
600 sysfs_remove_link(&sup->kobj, buf_con);
601err_con_dev:
602 sysfs_remove_link(&link->link_dev.kobj, "consumer");
603err_con:
604 sysfs_remove_link(&link->link_dev.kobj, "supplier");
605out:
606 return ret;
607}
608
609static void devlink_remove_symlinks(struct device *dev)
610{
611 char *buf_con __free(kfree) = NULL, *buf_sup __free(kfree) = NULL;
612 struct device_link *link = to_devlink(dev);
613 struct device *sup = link->supplier;
614 struct device *con = link->consumer;
615
616 sysfs_remove_link(&link->link_dev.kobj, "consumer");
617 sysfs_remove_link(&link->link_dev.kobj, "supplier");
618
619 if (device_is_registered(con)) {
620 buf_sup = kasprintf(GFP_KERNEL, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
621 if (!buf_sup)
622 goto out;
623 sysfs_remove_link(&con->kobj, buf_sup);
624 }
625
626 buf_con = kasprintf(GFP_KERNEL, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
627 if (!buf_con)
628 goto out;
629 sysfs_remove_link(&sup->kobj, buf_con);
630
631 return;
632
633out:
634 WARN(1, "Unable to properly free device link symlinks!\n");
635}
636
637static struct class_interface devlink_class_intf = {
638 .class = &devlink_class,
639 .add_dev = devlink_add_symlinks,
640 .remove_dev = devlink_remove_symlinks,
641};
642
643static int __init devlink_class_init(void)
644{
645 int ret;
646
647 ret = class_register(&devlink_class);
648 if (ret)
649 return ret;
650
651 ret = class_interface_register(&devlink_class_intf);
652 if (ret)
653 class_unregister(&devlink_class);
654
655 return ret;
656}
657postcore_initcall(devlink_class_init);
658
659#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
660 DL_FLAG_AUTOREMOVE_SUPPLIER | \
661 DL_FLAG_AUTOPROBE_CONSUMER | \
662 DL_FLAG_SYNC_STATE_ONLY | \
663 DL_FLAG_INFERRED | \
664 DL_FLAG_CYCLE)
665
666#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
667 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
668
669/**
670 * device_link_add - Create a link between two devices.
671 * @consumer: Consumer end of the link.
672 * @supplier: Supplier end of the link.
673 * @flags: Link flags.
674 *
675 * Return: On success, a device_link struct will be returned.
676 * On error or invalid flag settings, NULL will be returned.
677 *
678 * The caller is responsible for the proper synchronization of the link creation
679 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
680 * runtime PM framework to take the link into account. Second, if the
681 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
682 * be forced into the active meta state and reference-counted upon the creation
683 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
684 * ignored.
685 *
686 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
687 * expected to release the link returned by it directly with the help of either
688 * device_link_del() or device_link_remove().
689 *
690 * If that flag is not set, however, the caller of this function is handing the
691 * management of the link over to the driver core entirely and its return value
692 * can only be used to check whether or not the link is present. In that case,
693 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
694 * flags can be used to indicate to the driver core when the link can be safely
695 * deleted. Namely, setting one of them in @flags indicates to the driver core
696 * that the link is not going to be used (by the given caller of this function)
697 * after unbinding the consumer or supplier driver, respectively, from its
698 * device, so the link can be deleted at that point. If none of them is set,
699 * the link will be maintained until one of the devices pointed to by it (either
700 * the consumer or the supplier) is unregistered.
701 *
702 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
703 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
704 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
705 * be used to request the driver core to automatically probe for a consumer
706 * driver after successfully binding a driver to the supplier device.
707 *
708 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
709 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
710 * the same time is invalid and will cause NULL to be returned upfront.
711 * However, if a device link between the given @consumer and @supplier pair
712 * exists already when this function is called for them, the existing link will
713 * be returned regardless of its current type and status (the link's flags may
714 * be modified then). The caller of this function is then expected to treat
715 * the link as though it has just been created, so (in particular) if
716 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
717 * explicitly when not needed any more (as stated above).
718 *
719 * A side effect of the link creation is re-ordering of dpm_list and the
720 * devices_kset list by moving the consumer device and all devices depending
721 * on it to the ends of these lists (that does not happen to devices that have
722 * not been registered when this function is called).
723 *
724 * The supplier device is required to be registered when this function is called
725 * and NULL will be returned if that is not the case. The consumer device need
726 * not be registered, however.
727 */
728struct device_link *device_link_add(struct device *consumer,
729 struct device *supplier, u32 flags)
730{
731 struct device_link *link;
732
733 if (!consumer || !supplier || consumer == supplier ||
734 flags & ~DL_ADD_VALID_FLAGS ||
735 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
736 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
737 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
738 DL_FLAG_AUTOREMOVE_SUPPLIER)))
739 return NULL;
740
741 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
742 if (pm_runtime_get_sync(supplier) < 0) {
743 pm_runtime_put_noidle(supplier);
744 return NULL;
745 }
746 }
747
748 if (!(flags & DL_FLAG_STATELESS))
749 flags |= DL_FLAG_MANAGED;
750
751 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
752 !device_link_flag_is_sync_state_only(flags))
753 return NULL;
754
755 device_links_write_lock();
756 device_pm_lock();
757
758 /*
759 * If the supplier has not been fully registered yet or there is a
760 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
761 * the supplier already in the graph, return NULL. If the link is a
762 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
763 * because it only affects sync_state() callbacks.
764 */
765 if (!device_pm_initialized(supplier)
766 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
767 device_is_dependent(consumer, supplier))) {
768 link = NULL;
769 goto out;
770 }
771
772 /*
773 * SYNC_STATE_ONLY links are useless once a consumer device has probed.
774 * So, only create it if the consumer hasn't probed yet.
775 */
776 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
777 consumer->links.status != DL_DEV_NO_DRIVER &&
778 consumer->links.status != DL_DEV_PROBING) {
779 link = NULL;
780 goto out;
781 }
782
783 /*
784 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
785 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
786 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
787 */
788 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
789 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
790
791 list_for_each_entry(link, &supplier->links.consumers, s_node) {
792 if (link->consumer != consumer)
793 continue;
794
795 if (link->flags & DL_FLAG_INFERRED &&
796 !(flags & DL_FLAG_INFERRED))
797 link->flags &= ~DL_FLAG_INFERRED;
798
799 if (flags & DL_FLAG_PM_RUNTIME) {
800 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
801 pm_runtime_new_link(consumer);
802 link->flags |= DL_FLAG_PM_RUNTIME;
803 }
804 if (flags & DL_FLAG_RPM_ACTIVE)
805 refcount_inc(&link->rpm_active);
806 }
807
808 if (flags & DL_FLAG_STATELESS) {
809 kref_get(&link->kref);
810 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
811 !(link->flags & DL_FLAG_STATELESS)) {
812 link->flags |= DL_FLAG_STATELESS;
813 goto reorder;
814 } else {
815 link->flags |= DL_FLAG_STATELESS;
816 goto out;
817 }
818 }
819
820 /*
821 * If the life time of the link following from the new flags is
822 * longer than indicated by the flags of the existing link,
823 * update the existing link to stay around longer.
824 */
825 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
826 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
827 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
828 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
829 }
830 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
831 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
832 DL_FLAG_AUTOREMOVE_SUPPLIER);
833 }
834 if (!(link->flags & DL_FLAG_MANAGED)) {
835 kref_get(&link->kref);
836 link->flags |= DL_FLAG_MANAGED;
837 device_link_init_status(link, consumer, supplier);
838 }
839 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
840 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
841 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
842 goto reorder;
843 }
844
845 goto out;
846 }
847
848 link = kzalloc(sizeof(*link), GFP_KERNEL);
849 if (!link)
850 goto out;
851
852 refcount_set(&link->rpm_active, 1);
853
854 get_device(supplier);
855 link->supplier = supplier;
856 INIT_LIST_HEAD(&link->s_node);
857 get_device(consumer);
858 link->consumer = consumer;
859 INIT_LIST_HEAD(&link->c_node);
860 link->flags = flags;
861 kref_init(&link->kref);
862
863 link->link_dev.class = &devlink_class;
864 device_set_pm_not_required(&link->link_dev);
865 dev_set_name(&link->link_dev, "%s:%s--%s:%s",
866 dev_bus_name(supplier), dev_name(supplier),
867 dev_bus_name(consumer), dev_name(consumer));
868 if (device_register(&link->link_dev)) {
869 put_device(&link->link_dev);
870 link = NULL;
871 goto out;
872 }
873
874 if (flags & DL_FLAG_PM_RUNTIME) {
875 if (flags & DL_FLAG_RPM_ACTIVE)
876 refcount_inc(&link->rpm_active);
877
878 pm_runtime_new_link(consumer);
879 }
880
881 /* Determine the initial link state. */
882 if (flags & DL_FLAG_STATELESS)
883 link->status = DL_STATE_NONE;
884 else
885 device_link_init_status(link, consumer, supplier);
886
887 /*
888 * Some callers expect the link creation during consumer driver probe to
889 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
890 */
891 if (link->status == DL_STATE_CONSUMER_PROBE &&
892 flags & DL_FLAG_PM_RUNTIME)
893 pm_runtime_resume(supplier);
894
895 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
896 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
897
898 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
899 dev_dbg(consumer,
900 "Linked as a sync state only consumer to %s\n",
901 dev_name(supplier));
902 goto out;
903 }
904
905reorder:
906 /*
907 * Move the consumer and all of the devices depending on it to the end
908 * of dpm_list and the devices_kset list.
909 *
910 * It is necessary to hold dpm_list locked throughout all that or else
911 * we may end up suspending with a wrong ordering of it.
912 */
913 device_reorder_to_tail(consumer, NULL);
914
915 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
916
917out:
918 device_pm_unlock();
919 device_links_write_unlock();
920
921 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
922 pm_runtime_put(supplier);
923
924 return link;
925}
926EXPORT_SYMBOL_GPL(device_link_add);
927
928static void __device_link_del(struct kref *kref)
929{
930 struct device_link *link = container_of(kref, struct device_link, kref);
931
932 dev_dbg(link->consumer, "Dropping the link to %s\n",
933 dev_name(link->supplier));
934
935 pm_runtime_drop_link(link);
936
937 device_link_remove_from_lists(link);
938 device_unregister(&link->link_dev);
939}
940
941static void device_link_put_kref(struct device_link *link)
942{
943 if (link->flags & DL_FLAG_STATELESS)
944 kref_put(&link->kref, __device_link_del);
945 else if (!device_is_registered(link->consumer))
946 __device_link_del(&link->kref);
947 else
948 WARN(1, "Unable to drop a managed device link reference\n");
949}
950
951/**
952 * device_link_del - Delete a stateless link between two devices.
953 * @link: Device link to delete.
954 *
955 * The caller must ensure proper synchronization of this function with runtime
956 * PM. If the link was added multiple times, it needs to be deleted as often.
957 * Care is required for hotplugged devices: Their links are purged on removal
958 * and calling device_link_del() is then no longer allowed.
959 */
960void device_link_del(struct device_link *link)
961{
962 device_links_write_lock();
963 device_link_put_kref(link);
964 device_links_write_unlock();
965}
966EXPORT_SYMBOL_GPL(device_link_del);
967
968/**
969 * device_link_remove - Delete a stateless link between two devices.
970 * @consumer: Consumer end of the link.
971 * @supplier: Supplier end of the link.
972 *
973 * The caller must ensure proper synchronization of this function with runtime
974 * PM.
975 */
976void device_link_remove(void *consumer, struct device *supplier)
977{
978 struct device_link *link;
979
980 if (WARN_ON(consumer == supplier))
981 return;
982
983 device_links_write_lock();
984
985 list_for_each_entry(link, &supplier->links.consumers, s_node) {
986 if (link->consumer == consumer) {
987 device_link_put_kref(link);
988 break;
989 }
990 }
991
992 device_links_write_unlock();
993}
994EXPORT_SYMBOL_GPL(device_link_remove);
995
996static void device_links_missing_supplier(struct device *dev)
997{
998 struct device_link *link;
999
1000 list_for_each_entry(link, &dev->links.suppliers, c_node) {
1001 if (link->status != DL_STATE_CONSUMER_PROBE)
1002 continue;
1003
1004 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1005 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1006 } else {
1007 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1008 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1009 }
1010 }
1011}
1012
1013static bool dev_is_best_effort(struct device *dev)
1014{
1015 return (fw_devlink_best_effort && dev->can_match) ||
1016 (dev->fwnode && (dev->fwnode->flags & FWNODE_FLAG_BEST_EFFORT));
1017}
1018
1019static struct fwnode_handle *fwnode_links_check_suppliers(
1020 struct fwnode_handle *fwnode)
1021{
1022 struct fwnode_link *link;
1023
1024 if (!fwnode || fw_devlink_is_permissive())
1025 return NULL;
1026
1027 list_for_each_entry(link, &fwnode->suppliers, c_hook)
1028 if (!(link->flags &
1029 (FWLINK_FLAG_CYCLE | FWLINK_FLAG_IGNORE)))
1030 return link->supplier;
1031
1032 return NULL;
1033}
1034
1035/**
1036 * device_links_check_suppliers - Check presence of supplier drivers.
1037 * @dev: Consumer device.
1038 *
1039 * Check links from this device to any suppliers. Walk the list of the device's
1040 * links to suppliers and see if all of them are available. If not, simply
1041 * return -EPROBE_DEFER.
1042 *
1043 * We need to guarantee that the supplier will not go away after the check has
1044 * been positive here. It only can go away in __device_release_driver() and
1045 * that function checks the device's links to consumers. This means we need to
1046 * mark the link as "consumer probe in progress" to make the supplier removal
1047 * wait for us to complete (or bad things may happen).
1048 *
1049 * Links without the DL_FLAG_MANAGED flag set are ignored.
1050 */
1051int device_links_check_suppliers(struct device *dev)
1052{
1053 struct device_link *link;
1054 int ret = 0, fwnode_ret = 0;
1055 struct fwnode_handle *sup_fw;
1056
1057 /*
1058 * Device waiting for supplier to become available is not allowed to
1059 * probe.
1060 */
1061 scoped_guard(mutex, &fwnode_link_lock) {
1062 sup_fw = fwnode_links_check_suppliers(dev->fwnode);
1063 if (sup_fw) {
1064 if (dev_is_best_effort(dev))
1065 fwnode_ret = -EAGAIN;
1066 else
1067 return dev_err_probe(dev, -EPROBE_DEFER,
1068 "wait for supplier %pfwf\n", sup_fw);
1069 }
1070 }
1071
1072 device_links_write_lock();
1073
1074 list_for_each_entry(link, &dev->links.suppliers, c_node) {
1075 if (!(link->flags & DL_FLAG_MANAGED))
1076 continue;
1077
1078 if (link->status != DL_STATE_AVAILABLE &&
1079 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
1080
1081 if (dev_is_best_effort(dev) &&
1082 link->flags & DL_FLAG_INFERRED &&
1083 !link->supplier->can_match) {
1084 ret = -EAGAIN;
1085 continue;
1086 }
1087
1088 device_links_missing_supplier(dev);
1089 ret = dev_err_probe(dev, -EPROBE_DEFER,
1090 "supplier %s not ready\n", dev_name(link->supplier));
1091 break;
1092 }
1093 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1094 }
1095 dev->links.status = DL_DEV_PROBING;
1096
1097 device_links_write_unlock();
1098
1099 return ret ? ret : fwnode_ret;
1100}
1101
1102/**
1103 * __device_links_queue_sync_state - Queue a device for sync_state() callback
1104 * @dev: Device to call sync_state() on
1105 * @list: List head to queue the @dev on
1106 *
1107 * Queues a device for a sync_state() callback when the device links write lock
1108 * isn't held. This allows the sync_state() execution flow to use device links
1109 * APIs. The caller must ensure this function is called with
1110 * device_links_write_lock() held.
1111 *
1112 * This function does a get_device() to make sure the device is not freed while
1113 * on this list.
1114 *
1115 * So the caller must also ensure that device_links_flush_sync_list() is called
1116 * as soon as the caller releases device_links_write_lock(). This is necessary
1117 * to make sure the sync_state() is called in a timely fashion and the
1118 * put_device() is called on this device.
1119 */
1120static void __device_links_queue_sync_state(struct device *dev,
1121 struct list_head *list)
1122{
1123 struct device_link *link;
1124
1125 if (!dev_has_sync_state(dev))
1126 return;
1127 if (dev->state_synced)
1128 return;
1129
1130 list_for_each_entry(link, &dev->links.consumers, s_node) {
1131 if (!(link->flags & DL_FLAG_MANAGED))
1132 continue;
1133 if (link->status != DL_STATE_ACTIVE)
1134 return;
1135 }
1136
1137 /*
1138 * Set the flag here to avoid adding the same device to a list more
1139 * than once. This can happen if new consumers get added to the device
1140 * and probed before the list is flushed.
1141 */
1142 dev->state_synced = true;
1143
1144 if (WARN_ON(!list_empty(&dev->links.defer_sync)))
1145 return;
1146
1147 get_device(dev);
1148 list_add_tail(&dev->links.defer_sync, list);
1149}
1150
1151/**
1152 * device_links_flush_sync_list - Call sync_state() on a list of devices
1153 * @list: List of devices to call sync_state() on
1154 * @dont_lock_dev: Device for which lock is already held by the caller
1155 *
1156 * Calls sync_state() on all the devices that have been queued for it. This
1157 * function is used in conjunction with __device_links_queue_sync_state(). The
1158 * @dont_lock_dev parameter is useful when this function is called from a
1159 * context where a device lock is already held.
1160 */
1161static void device_links_flush_sync_list(struct list_head *list,
1162 struct device *dont_lock_dev)
1163{
1164 struct device *dev, *tmp;
1165
1166 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
1167 list_del_init(&dev->links.defer_sync);
1168
1169 if (dev != dont_lock_dev)
1170 device_lock(dev);
1171
1172 dev_sync_state(dev);
1173
1174 if (dev != dont_lock_dev)
1175 device_unlock(dev);
1176
1177 put_device(dev);
1178 }
1179}
1180
1181void device_links_supplier_sync_state_pause(void)
1182{
1183 device_links_write_lock();
1184 defer_sync_state_count++;
1185 device_links_write_unlock();
1186}
1187
1188void device_links_supplier_sync_state_resume(void)
1189{
1190 struct device *dev, *tmp;
1191 LIST_HEAD(sync_list);
1192
1193 device_links_write_lock();
1194 if (!defer_sync_state_count) {
1195 WARN(true, "Unmatched sync_state pause/resume!");
1196 goto out;
1197 }
1198 defer_sync_state_count--;
1199 if (defer_sync_state_count)
1200 goto out;
1201
1202 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
1203 /*
1204 * Delete from deferred_sync list before queuing it to
1205 * sync_list because defer_sync is used for both lists.
1206 */
1207 list_del_init(&dev->links.defer_sync);
1208 __device_links_queue_sync_state(dev, &sync_list);
1209 }
1210out:
1211 device_links_write_unlock();
1212
1213 device_links_flush_sync_list(&sync_list, NULL);
1214}
1215
1216static int sync_state_resume_initcall(void)
1217{
1218 device_links_supplier_sync_state_resume();
1219 return 0;
1220}
1221late_initcall(sync_state_resume_initcall);
1222
1223static void __device_links_supplier_defer_sync(struct device *sup)
1224{
1225 if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup))
1226 list_add_tail(&sup->links.defer_sync, &deferred_sync);
1227}
1228
1229static void device_link_drop_managed(struct device_link *link)
1230{
1231 link->flags &= ~DL_FLAG_MANAGED;
1232 WRITE_ONCE(link->status, DL_STATE_NONE);
1233 kref_put(&link->kref, __device_link_del);
1234}
1235
1236static ssize_t waiting_for_supplier_show(struct device *dev,
1237 struct device_attribute *attr,
1238 char *buf)
1239{
1240 bool val;
1241
1242 device_lock(dev);
1243 scoped_guard(mutex, &fwnode_link_lock)
1244 val = !!fwnode_links_check_suppliers(dev->fwnode);
1245 device_unlock(dev);
1246 return sysfs_emit(buf, "%u\n", val);
1247}
1248static DEVICE_ATTR_RO(waiting_for_supplier);
1249
1250/**
1251 * device_links_force_bind - Prepares device to be force bound
1252 * @dev: Consumer device.
1253 *
1254 * device_bind_driver() force binds a device to a driver without calling any
1255 * driver probe functions. So the consumer really isn't going to wait for any
1256 * supplier before it's bound to the driver. We still want the device link
1257 * states to be sensible when this happens.
1258 *
1259 * In preparation for device_bind_driver(), this function goes through each
1260 * supplier device links and checks if the supplier is bound. If it is, then
1261 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link
1262 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.
1263 */
1264void device_links_force_bind(struct device *dev)
1265{
1266 struct device_link *link, *ln;
1267
1268 device_links_write_lock();
1269
1270 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1271 if (!(link->flags & DL_FLAG_MANAGED))
1272 continue;
1273
1274 if (link->status != DL_STATE_AVAILABLE) {
1275 device_link_drop_managed(link);
1276 continue;
1277 }
1278 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1279 }
1280 dev->links.status = DL_DEV_PROBING;
1281
1282 device_links_write_unlock();
1283}
1284
1285/**
1286 * device_links_driver_bound - Update device links after probing its driver.
1287 * @dev: Device to update the links for.
1288 *
1289 * The probe has been successful, so update links from this device to any
1290 * consumers by changing their status to "available".
1291 *
1292 * Also change the status of @dev's links to suppliers to "active".
1293 *
1294 * Links without the DL_FLAG_MANAGED flag set are ignored.
1295 */
1296void device_links_driver_bound(struct device *dev)
1297{
1298 struct device_link *link, *ln;
1299 LIST_HEAD(sync_list);
1300
1301 /*
1302 * If a device binds successfully, it's expected to have created all
1303 * the device links it needs to or make new device links as it needs
1304 * them. So, fw_devlink no longer needs to create device links to any
1305 * of the device's suppliers.
1306 *
1307 * Also, if a child firmware node of this bound device is not added as a
1308 * device by now, assume it is never going to be added. Make this bound
1309 * device the fallback supplier to the dangling consumers of the child
1310 * firmware node because this bound device is probably implementing the
1311 * child firmware node functionality and we don't want the dangling
1312 * consumers to defer probe indefinitely waiting for a device for the
1313 * child firmware node.
1314 */
1315 if (dev->fwnode && dev->fwnode->dev == dev) {
1316 struct fwnode_handle *child;
1317
1318 fwnode_links_purge_suppliers(dev->fwnode);
1319
1320 guard(mutex)(&fwnode_link_lock);
1321
1322 fwnode_for_each_available_child_node(dev->fwnode, child)
1323 __fw_devlink_pickup_dangling_consumers(child,
1324 dev->fwnode);
1325 __fw_devlink_link_to_consumers(dev);
1326 }
1327 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1328
1329 device_links_write_lock();
1330
1331 list_for_each_entry(link, &dev->links.consumers, s_node) {
1332 if (!(link->flags & DL_FLAG_MANAGED))
1333 continue;
1334
1335 /*
1336 * Links created during consumer probe may be in the "consumer
1337 * probe" state to start with if the supplier is still probing
1338 * when they are created and they may become "active" if the
1339 * consumer probe returns first. Skip them here.
1340 */
1341 if (link->status == DL_STATE_CONSUMER_PROBE ||
1342 link->status == DL_STATE_ACTIVE)
1343 continue;
1344
1345 WARN_ON(link->status != DL_STATE_DORMANT);
1346 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1347
1348 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1349 driver_deferred_probe_add(link->consumer);
1350 }
1351
1352 if (defer_sync_state_count)
1353 __device_links_supplier_defer_sync(dev);
1354 else
1355 __device_links_queue_sync_state(dev, &sync_list);
1356
1357 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1358 struct device *supplier;
1359
1360 if (!(link->flags & DL_FLAG_MANAGED))
1361 continue;
1362
1363 supplier = link->supplier;
1364 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1365 /*
1366 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1367 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1368 * save to drop the managed link completely.
1369 */
1370 device_link_drop_managed(link);
1371 } else if (dev_is_best_effort(dev) &&
1372 link->flags & DL_FLAG_INFERRED &&
1373 link->status != DL_STATE_CONSUMER_PROBE &&
1374 !link->supplier->can_match) {
1375 /*
1376 * When dev_is_best_effort() is true, we ignore device
1377 * links to suppliers that don't have a driver. If the
1378 * consumer device still managed to probe, there's no
1379 * point in maintaining a device link in a weird state
1380 * (consumer probed before supplier). So delete it.
1381 */
1382 device_link_drop_managed(link);
1383 } else {
1384 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1385 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1386 }
1387
1388 /*
1389 * This needs to be done even for the deleted
1390 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1391 * device link that was preventing the supplier from getting a
1392 * sync_state() call.
1393 */
1394 if (defer_sync_state_count)
1395 __device_links_supplier_defer_sync(supplier);
1396 else
1397 __device_links_queue_sync_state(supplier, &sync_list);
1398 }
1399
1400 dev->links.status = DL_DEV_DRIVER_BOUND;
1401
1402 device_links_write_unlock();
1403
1404 device_links_flush_sync_list(&sync_list, dev);
1405}
1406
1407/**
1408 * __device_links_no_driver - Update links of a device without a driver.
1409 * @dev: Device without a drvier.
1410 *
1411 * Delete all non-persistent links from this device to any suppliers.
1412 *
1413 * Persistent links stay around, but their status is changed to "available",
1414 * unless they already are in the "supplier unbind in progress" state in which
1415 * case they need not be updated.
1416 *
1417 * Links without the DL_FLAG_MANAGED flag set are ignored.
1418 */
1419static void __device_links_no_driver(struct device *dev)
1420{
1421 struct device_link *link, *ln;
1422
1423 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1424 if (!(link->flags & DL_FLAG_MANAGED))
1425 continue;
1426
1427 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1428 device_link_drop_managed(link);
1429 continue;
1430 }
1431
1432 if (link->status != DL_STATE_CONSUMER_PROBE &&
1433 link->status != DL_STATE_ACTIVE)
1434 continue;
1435
1436 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1437 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1438 } else {
1439 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1440 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1441 }
1442 }
1443
1444 dev->links.status = DL_DEV_NO_DRIVER;
1445}
1446
1447/**
1448 * device_links_no_driver - Update links after failing driver probe.
1449 * @dev: Device whose driver has just failed to probe.
1450 *
1451 * Clean up leftover links to consumers for @dev and invoke
1452 * %__device_links_no_driver() to update links to suppliers for it as
1453 * appropriate.
1454 *
1455 * Links without the DL_FLAG_MANAGED flag set are ignored.
1456 */
1457void device_links_no_driver(struct device *dev)
1458{
1459 struct device_link *link;
1460
1461 device_links_write_lock();
1462
1463 list_for_each_entry(link, &dev->links.consumers, s_node) {
1464 if (!(link->flags & DL_FLAG_MANAGED))
1465 continue;
1466
1467 /*
1468 * The probe has failed, so if the status of the link is
1469 * "consumer probe" or "active", it must have been added by
1470 * a probing consumer while this device was still probing.
1471 * Change its state to "dormant", as it represents a valid
1472 * relationship, but it is not functionally meaningful.
1473 */
1474 if (link->status == DL_STATE_CONSUMER_PROBE ||
1475 link->status == DL_STATE_ACTIVE)
1476 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1477 }
1478
1479 __device_links_no_driver(dev);
1480
1481 device_links_write_unlock();
1482}
1483
1484/**
1485 * device_links_driver_cleanup - Update links after driver removal.
1486 * @dev: Device whose driver has just gone away.
1487 *
1488 * Update links to consumers for @dev by changing their status to "dormant" and
1489 * invoke %__device_links_no_driver() to update links to suppliers for it as
1490 * appropriate.
1491 *
1492 * Links without the DL_FLAG_MANAGED flag set are ignored.
1493 */
1494void device_links_driver_cleanup(struct device *dev)
1495{
1496 struct device_link *link, *ln;
1497
1498 device_links_write_lock();
1499
1500 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1501 if (!(link->flags & DL_FLAG_MANAGED))
1502 continue;
1503
1504 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1505 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1506
1507 /*
1508 * autoremove the links between this @dev and its consumer
1509 * devices that are not active, i.e. where the link state
1510 * has moved to DL_STATE_SUPPLIER_UNBIND.
1511 */
1512 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1513 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1514 device_link_drop_managed(link);
1515
1516 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1517 }
1518
1519 list_del_init(&dev->links.defer_sync);
1520 __device_links_no_driver(dev);
1521
1522 device_links_write_unlock();
1523}
1524
1525/**
1526 * device_links_busy - Check if there are any busy links to consumers.
1527 * @dev: Device to check.
1528 *
1529 * Check each consumer of the device and return 'true' if its link's status
1530 * is one of "consumer probe" or "active" (meaning that the given consumer is
1531 * probing right now or its driver is present). Otherwise, change the link
1532 * state to "supplier unbind" to prevent the consumer from being probed
1533 * successfully going forward.
1534 *
1535 * Return 'false' if there are no probing or active consumers.
1536 *
1537 * Links without the DL_FLAG_MANAGED flag set are ignored.
1538 */
1539bool device_links_busy(struct device *dev)
1540{
1541 struct device_link *link;
1542 bool ret = false;
1543
1544 device_links_write_lock();
1545
1546 list_for_each_entry(link, &dev->links.consumers, s_node) {
1547 if (!(link->flags & DL_FLAG_MANAGED))
1548 continue;
1549
1550 if (link->status == DL_STATE_CONSUMER_PROBE
1551 || link->status == DL_STATE_ACTIVE) {
1552 ret = true;
1553 break;
1554 }
1555 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1556 }
1557
1558 dev->links.status = DL_DEV_UNBINDING;
1559
1560 device_links_write_unlock();
1561 return ret;
1562}
1563
1564/**
1565 * device_links_unbind_consumers - Force unbind consumers of the given device.
1566 * @dev: Device to unbind the consumers of.
1567 *
1568 * Walk the list of links to consumers for @dev and if any of them is in the
1569 * "consumer probe" state, wait for all device probes in progress to complete
1570 * and start over.
1571 *
1572 * If that's not the case, change the status of the link to "supplier unbind"
1573 * and check if the link was in the "active" state. If so, force the consumer
1574 * driver to unbind and start over (the consumer will not re-probe as we have
1575 * changed the state of the link already).
1576 *
1577 * Links without the DL_FLAG_MANAGED flag set are ignored.
1578 */
1579void device_links_unbind_consumers(struct device *dev)
1580{
1581 struct device_link *link;
1582
1583 start:
1584 device_links_write_lock();
1585
1586 list_for_each_entry(link, &dev->links.consumers, s_node) {
1587 enum device_link_state status;
1588
1589 if (!(link->flags & DL_FLAG_MANAGED) ||
1590 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1591 continue;
1592
1593 status = link->status;
1594 if (status == DL_STATE_CONSUMER_PROBE) {
1595 device_links_write_unlock();
1596
1597 wait_for_device_probe();
1598 goto start;
1599 }
1600 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1601 if (status == DL_STATE_ACTIVE) {
1602 struct device *consumer = link->consumer;
1603
1604 get_device(consumer);
1605
1606 device_links_write_unlock();
1607
1608 device_release_driver_internal(consumer, NULL,
1609 consumer->parent);
1610 put_device(consumer);
1611 goto start;
1612 }
1613 }
1614
1615 device_links_write_unlock();
1616}
1617
1618/**
1619 * device_links_purge - Delete existing links to other devices.
1620 * @dev: Target device.
1621 */
1622static void device_links_purge(struct device *dev)
1623{
1624 struct device_link *link, *ln;
1625
1626 if (dev->class == &devlink_class)
1627 return;
1628
1629 /*
1630 * Delete all of the remaining links from this device to any other
1631 * devices (either consumers or suppliers).
1632 */
1633 device_links_write_lock();
1634
1635 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1636 WARN_ON(link->status == DL_STATE_ACTIVE);
1637 __device_link_del(&link->kref);
1638 }
1639
1640 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1641 WARN_ON(link->status != DL_STATE_DORMANT &&
1642 link->status != DL_STATE_NONE);
1643 __device_link_del(&link->kref);
1644 }
1645
1646 device_links_write_unlock();
1647}
1648
1649#define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \
1650 DL_FLAG_SYNC_STATE_ONLY)
1651#define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \
1652 DL_FLAG_AUTOPROBE_CONSUMER)
1653#define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \
1654 DL_FLAG_PM_RUNTIME)
1655
1656static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1657static int __init fw_devlink_setup(char *arg)
1658{
1659 if (!arg)
1660 return -EINVAL;
1661
1662 if (strcmp(arg, "off") == 0) {
1663 fw_devlink_flags = 0;
1664 } else if (strcmp(arg, "permissive") == 0) {
1665 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1666 } else if (strcmp(arg, "on") == 0) {
1667 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1668 } else if (strcmp(arg, "rpm") == 0) {
1669 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1670 }
1671 return 0;
1672}
1673early_param("fw_devlink", fw_devlink_setup);
1674
1675static bool fw_devlink_strict;
1676static int __init fw_devlink_strict_setup(char *arg)
1677{
1678 return kstrtobool(arg, &fw_devlink_strict);
1679}
1680early_param("fw_devlink.strict", fw_devlink_strict_setup);
1681
1682#define FW_DEVLINK_SYNC_STATE_STRICT 0
1683#define FW_DEVLINK_SYNC_STATE_TIMEOUT 1
1684
1685#ifndef CONFIG_FW_DEVLINK_SYNC_STATE_TIMEOUT
1686static int fw_devlink_sync_state;
1687#else
1688static int fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_TIMEOUT;
1689#endif
1690
1691static int __init fw_devlink_sync_state_setup(char *arg)
1692{
1693 if (!arg)
1694 return -EINVAL;
1695
1696 if (strcmp(arg, "strict") == 0) {
1697 fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_STRICT;
1698 return 0;
1699 } else if (strcmp(arg, "timeout") == 0) {
1700 fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_TIMEOUT;
1701 return 0;
1702 }
1703 return -EINVAL;
1704}
1705early_param("fw_devlink.sync_state", fw_devlink_sync_state_setup);
1706
1707static inline u32 fw_devlink_get_flags(u8 fwlink_flags)
1708{
1709 if (fwlink_flags & FWLINK_FLAG_CYCLE)
1710 return FW_DEVLINK_FLAGS_PERMISSIVE | DL_FLAG_CYCLE;
1711
1712 return fw_devlink_flags;
1713}
1714
1715static bool fw_devlink_is_permissive(void)
1716{
1717 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE;
1718}
1719
1720bool fw_devlink_is_strict(void)
1721{
1722 return fw_devlink_strict && !fw_devlink_is_permissive();
1723}
1724
1725static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)
1726{
1727 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)
1728 return;
1729
1730 fwnode_call_int_op(fwnode, add_links);
1731 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;
1732}
1733
1734static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
1735{
1736 struct fwnode_handle *child = NULL;
1737
1738 fw_devlink_parse_fwnode(fwnode);
1739
1740 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1741 fw_devlink_parse_fwtree(child);
1742}
1743
1744static void fw_devlink_relax_link(struct device_link *link)
1745{
1746 if (!(link->flags & DL_FLAG_INFERRED))
1747 return;
1748
1749 if (device_link_flag_is_sync_state_only(link->flags))
1750 return;
1751
1752 pm_runtime_drop_link(link);
1753 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE;
1754 dev_dbg(link->consumer, "Relaxing link with %s\n",
1755 dev_name(link->supplier));
1756}
1757
1758static int fw_devlink_no_driver(struct device *dev, void *data)
1759{
1760 struct device_link *link = to_devlink(dev);
1761
1762 if (!link->supplier->can_match)
1763 fw_devlink_relax_link(link);
1764
1765 return 0;
1766}
1767
1768void fw_devlink_drivers_done(void)
1769{
1770 fw_devlink_drv_reg_done = true;
1771 device_links_write_lock();
1772 class_for_each_device(&devlink_class, NULL, NULL,
1773 fw_devlink_no_driver);
1774 device_links_write_unlock();
1775}
1776
1777static int fw_devlink_dev_sync_state(struct device *dev, void *data)
1778{
1779 struct device_link *link = to_devlink(dev);
1780 struct device *sup = link->supplier;
1781
1782 if (!(link->flags & DL_FLAG_MANAGED) ||
1783 link->status == DL_STATE_ACTIVE || sup->state_synced ||
1784 !dev_has_sync_state(sup))
1785 return 0;
1786
1787 if (fw_devlink_sync_state == FW_DEVLINK_SYNC_STATE_STRICT) {
1788 dev_warn(sup, "sync_state() pending due to %s\n",
1789 dev_name(link->consumer));
1790 return 0;
1791 }
1792
1793 if (!list_empty(&sup->links.defer_sync))
1794 return 0;
1795
1796 dev_warn(sup, "Timed out. Forcing sync_state()\n");
1797 sup->state_synced = true;
1798 get_device(sup);
1799 list_add_tail(&sup->links.defer_sync, data);
1800
1801 return 0;
1802}
1803
1804void fw_devlink_probing_done(void)
1805{
1806 LIST_HEAD(sync_list);
1807
1808 device_links_write_lock();
1809 class_for_each_device(&devlink_class, NULL, &sync_list,
1810 fw_devlink_dev_sync_state);
1811 device_links_write_unlock();
1812 device_links_flush_sync_list(&sync_list, NULL);
1813}
1814
1815/**
1816 * wait_for_init_devices_probe - Try to probe any device needed for init
1817 *
1818 * Some devices might need to be probed and bound successfully before the kernel
1819 * boot sequence can finish and move on to init/userspace. For example, a
1820 * network interface might need to be bound to be able to mount a NFS rootfs.
1821 *
1822 * With fw_devlink=on by default, some of these devices might be blocked from
1823 * probing because they are waiting on a optional supplier that doesn't have a
1824 * driver. While fw_devlink will eventually identify such devices and unblock
1825 * the probing automatically, it might be too late by the time it unblocks the
1826 * probing of devices. For example, the IP4 autoconfig might timeout before
1827 * fw_devlink unblocks probing of the network interface.
1828 *
1829 * This function is available to temporarily try and probe all devices that have
1830 * a driver even if some of their suppliers haven't been added or don't have
1831 * drivers.
1832 *
1833 * The drivers can then decide which of the suppliers are optional vs mandatory
1834 * and probe the device if possible. By the time this function returns, all such
1835 * "best effort" probes are guaranteed to be completed. If a device successfully
1836 * probes in this mode, we delete all fw_devlink discovered dependencies of that
1837 * device where the supplier hasn't yet probed successfully because they have to
1838 * be optional dependencies.
1839 *
1840 * Any devices that didn't successfully probe go back to being treated as if
1841 * this function was never called.
1842 *
1843 * This also means that some devices that aren't needed for init and could have
1844 * waited for their optional supplier to probe (when the supplier's module is
1845 * loaded later on) would end up probing prematurely with limited functionality.
1846 * So call this function only when boot would fail without it.
1847 */
1848void __init wait_for_init_devices_probe(void)
1849{
1850 if (!fw_devlink_flags || fw_devlink_is_permissive())
1851 return;
1852
1853 /*
1854 * Wait for all ongoing probes to finish so that the "best effort" is
1855 * only applied to devices that can't probe otherwise.
1856 */
1857 wait_for_device_probe();
1858
1859 pr_info("Trying to probe devices needed for running init ...\n");
1860 fw_devlink_best_effort = true;
1861 driver_deferred_probe_trigger();
1862
1863 /*
1864 * Wait for all "best effort" probes to finish before going back to
1865 * normal enforcement.
1866 */
1867 wait_for_device_probe();
1868 fw_devlink_best_effort = false;
1869}
1870
1871static void fw_devlink_unblock_consumers(struct device *dev)
1872{
1873 struct device_link *link;
1874
1875 if (!fw_devlink_flags || fw_devlink_is_permissive())
1876 return;
1877
1878 device_links_write_lock();
1879 list_for_each_entry(link, &dev->links.consumers, s_node)
1880 fw_devlink_relax_link(link);
1881 device_links_write_unlock();
1882}
1883
1884#define get_dev_from_fwnode(fwnode) get_device((fwnode)->dev)
1885
1886static bool fwnode_init_without_drv(struct fwnode_handle *fwnode)
1887{
1888 struct device *dev;
1889 bool ret;
1890
1891 if (!(fwnode->flags & FWNODE_FLAG_INITIALIZED))
1892 return false;
1893
1894 dev = get_dev_from_fwnode(fwnode);
1895 ret = !dev || dev->links.status == DL_DEV_NO_DRIVER;
1896 put_device(dev);
1897
1898 return ret;
1899}
1900
1901static bool fwnode_ancestor_init_without_drv(struct fwnode_handle *fwnode)
1902{
1903 struct fwnode_handle *parent;
1904
1905 fwnode_for_each_parent_node(fwnode, parent) {
1906 if (fwnode_init_without_drv(parent)) {
1907 fwnode_handle_put(parent);
1908 return true;
1909 }
1910 }
1911
1912 return false;
1913}
1914
1915/**
1916 * fwnode_is_ancestor_of - Test if @ancestor is ancestor of @child
1917 * @ancestor: Firmware which is tested for being an ancestor
1918 * @child: Firmware which is tested for being the child
1919 *
1920 * A node is considered an ancestor of itself too.
1921 *
1922 * Return: true if @ancestor is an ancestor of @child. Otherwise, returns false.
1923 */
1924static bool fwnode_is_ancestor_of(const struct fwnode_handle *ancestor,
1925 const struct fwnode_handle *child)
1926{
1927 struct fwnode_handle *parent;
1928
1929 if (IS_ERR_OR_NULL(ancestor))
1930 return false;
1931
1932 if (child == ancestor)
1933 return true;
1934
1935 fwnode_for_each_parent_node(child, parent) {
1936 if (parent == ancestor) {
1937 fwnode_handle_put(parent);
1938 return true;
1939 }
1940 }
1941 return false;
1942}
1943
1944/**
1945 * fwnode_get_next_parent_dev - Find device of closest ancestor fwnode
1946 * @fwnode: firmware node
1947 *
1948 * Given a firmware node (@fwnode), this function finds its closest ancestor
1949 * firmware node that has a corresponding struct device and returns that struct
1950 * device.
1951 *
1952 * The caller is responsible for calling put_device() on the returned device
1953 * pointer.
1954 *
1955 * Return: a pointer to the device of the @fwnode's closest ancestor.
1956 */
1957static struct device *fwnode_get_next_parent_dev(const struct fwnode_handle *fwnode)
1958{
1959 struct fwnode_handle *parent;
1960 struct device *dev;
1961
1962 fwnode_for_each_parent_node(fwnode, parent) {
1963 dev = get_dev_from_fwnode(parent);
1964 if (dev) {
1965 fwnode_handle_put(parent);
1966 return dev;
1967 }
1968 }
1969 return NULL;
1970}
1971
1972/**
1973 * __fw_devlink_relax_cycles - Relax and mark dependency cycles.
1974 * @con_handle: Potential consumer device fwnode.
1975 * @sup_handle: Potential supplier's fwnode.
1976 *
1977 * Needs to be called with fwnode_lock and device link lock held.
1978 *
1979 * Check if @sup_handle or any of its ancestors or suppliers direct/indirectly
1980 * depend on @con. This function can detect multiple cyles between @sup_handle
1981 * and @con. When such dependency cycles are found, convert all device links
1982 * created solely by fw_devlink into SYNC_STATE_ONLY device links. Also, mark
1983 * all fwnode links in the cycle with FWLINK_FLAG_CYCLE so that when they are
1984 * converted into a device link in the future, they are created as
1985 * SYNC_STATE_ONLY device links. This is the equivalent of doing
1986 * fw_devlink=permissive just between the devices in the cycle. We need to do
1987 * this because, at this point, fw_devlink can't tell which of these
1988 * dependencies is not a real dependency.
1989 *
1990 * Return true if one or more cycles were found. Otherwise, return false.
1991 */
1992static bool __fw_devlink_relax_cycles(struct fwnode_handle *con_handle,
1993 struct fwnode_handle *sup_handle)
1994{
1995 struct device *sup_dev = NULL, *par_dev = NULL, *con_dev = NULL;
1996 struct fwnode_link *link;
1997 struct device_link *dev_link;
1998 bool ret = false;
1999
2000 if (!sup_handle)
2001 return false;
2002
2003 /*
2004 * We aren't trying to find all cycles. Just a cycle between con and
2005 * sup_handle.
2006 */
2007 if (sup_handle->flags & FWNODE_FLAG_VISITED)
2008 return false;
2009
2010 sup_handle->flags |= FWNODE_FLAG_VISITED;
2011
2012 /* Termination condition. */
2013 if (sup_handle == con_handle) {
2014 pr_debug("----- cycle: start -----\n");
2015 ret = true;
2016 goto out;
2017 }
2018
2019 sup_dev = get_dev_from_fwnode(sup_handle);
2020 con_dev = get_dev_from_fwnode(con_handle);
2021 /*
2022 * If sup_dev is bound to a driver and @con hasn't started binding to a
2023 * driver, sup_dev can't be a consumer of @con. So, no need to check
2024 * further.
2025 */
2026 if (sup_dev && sup_dev->links.status == DL_DEV_DRIVER_BOUND &&
2027 con_dev && con_dev->links.status == DL_DEV_NO_DRIVER) {
2028 ret = false;
2029 goto out;
2030 }
2031
2032 list_for_each_entry(link, &sup_handle->suppliers, c_hook) {
2033 if (link->flags & FWLINK_FLAG_IGNORE)
2034 continue;
2035
2036 if (__fw_devlink_relax_cycles(con_handle, link->supplier)) {
2037 __fwnode_link_cycle(link);
2038 ret = true;
2039 }
2040 }
2041
2042 /*
2043 * Give priority to device parent over fwnode parent to account for any
2044 * quirks in how fwnodes are converted to devices.
2045 */
2046 if (sup_dev)
2047 par_dev = get_device(sup_dev->parent);
2048 else
2049 par_dev = fwnode_get_next_parent_dev(sup_handle);
2050
2051 if (par_dev && __fw_devlink_relax_cycles(con_handle, par_dev->fwnode)) {
2052 pr_debug("%pfwf: cycle: child of %pfwf\n", sup_handle,
2053 par_dev->fwnode);
2054 ret = true;
2055 }
2056
2057 if (!sup_dev)
2058 goto out;
2059
2060 list_for_each_entry(dev_link, &sup_dev->links.suppliers, c_node) {
2061 /*
2062 * Ignore a SYNC_STATE_ONLY flag only if it wasn't marked as
2063 * such due to a cycle.
2064 */
2065 if (device_link_flag_is_sync_state_only(dev_link->flags) &&
2066 !(dev_link->flags & DL_FLAG_CYCLE))
2067 continue;
2068
2069 if (__fw_devlink_relax_cycles(con_handle,
2070 dev_link->supplier->fwnode)) {
2071 pr_debug("%pfwf: cycle: depends on %pfwf\n", sup_handle,
2072 dev_link->supplier->fwnode);
2073 fw_devlink_relax_link(dev_link);
2074 dev_link->flags |= DL_FLAG_CYCLE;
2075 ret = true;
2076 }
2077 }
2078
2079out:
2080 sup_handle->flags &= ~FWNODE_FLAG_VISITED;
2081 put_device(sup_dev);
2082 put_device(con_dev);
2083 put_device(par_dev);
2084 return ret;
2085}
2086
2087/**
2088 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
2089 * @con: consumer device for the device link
2090 * @sup_handle: fwnode handle of supplier
2091 * @link: fwnode link that's being converted to a device link
2092 *
2093 * This function will try to create a device link between the consumer device
2094 * @con and the supplier device represented by @sup_handle.
2095 *
2096 * The supplier has to be provided as a fwnode because incorrect cycles in
2097 * fwnode links can sometimes cause the supplier device to never be created.
2098 * This function detects such cases and returns an error if it cannot create a
2099 * device link from the consumer to a missing supplier.
2100 *
2101 * Returns,
2102 * 0 on successfully creating a device link
2103 * -EINVAL if the device link cannot be created as expected
2104 * -EAGAIN if the device link cannot be created right now, but it may be
2105 * possible to do that in the future
2106 */
2107static int fw_devlink_create_devlink(struct device *con,
2108 struct fwnode_handle *sup_handle,
2109 struct fwnode_link *link)
2110{
2111 struct device *sup_dev;
2112 int ret = 0;
2113 u32 flags;
2114
2115 if (link->flags & FWLINK_FLAG_IGNORE)
2116 return 0;
2117
2118 /*
2119 * In some cases, a device P might also be a supplier to its child node
2120 * C. However, this would defer the probe of C until the probe of P
2121 * completes successfully. This is perfectly fine in the device driver
2122 * model. device_add() doesn't guarantee probe completion of the device
2123 * by the time it returns.
2124 *
2125 * However, there are a few drivers that assume C will finish probing
2126 * as soon as it's added and before P finishes probing. So, we provide
2127 * a flag to let fw_devlink know not to delay the probe of C until the
2128 * probe of P completes successfully.
2129 *
2130 * When such a flag is set, we can't create device links where P is the
2131 * supplier of C as that would delay the probe of C.
2132 */
2133 if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD &&
2134 fwnode_is_ancestor_of(sup_handle, con->fwnode))
2135 return -EINVAL;
2136
2137 /*
2138 * Don't try to optimize by not calling the cycle detection logic under
2139 * certain conditions. There's always some corner case that won't get
2140 * detected.
2141 */
2142 device_links_write_lock();
2143 if (__fw_devlink_relax_cycles(link->consumer, sup_handle)) {
2144 __fwnode_link_cycle(link);
2145 pr_debug("----- cycle: end -----\n");
2146 pr_info("%pfwf: Fixed dependency cycle(s) with %pfwf\n",
2147 link->consumer, sup_handle);
2148 }
2149 device_links_write_unlock();
2150
2151 if (con->fwnode == link->consumer)
2152 flags = fw_devlink_get_flags(link->flags);
2153 else
2154 flags = FW_DEVLINK_FLAGS_PERMISSIVE;
2155
2156 if (sup_handle->flags & FWNODE_FLAG_NOT_DEVICE)
2157 sup_dev = fwnode_get_next_parent_dev(sup_handle);
2158 else
2159 sup_dev = get_dev_from_fwnode(sup_handle);
2160
2161 if (sup_dev) {
2162 /*
2163 * If it's one of those drivers that don't actually bind to
2164 * their device using driver core, then don't wait on this
2165 * supplier device indefinitely.
2166 */
2167 if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
2168 sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
2169 dev_dbg(con,
2170 "Not linking %pfwf - dev might never probe\n",
2171 sup_handle);
2172 ret = -EINVAL;
2173 goto out;
2174 }
2175
2176 if (con != sup_dev && !device_link_add(con, sup_dev, flags)) {
2177 dev_err(con, "Failed to create device link (0x%x) with supplier %s for %pfwf\n",
2178 flags, dev_name(sup_dev), link->consumer);
2179 ret = -EINVAL;
2180 }
2181
2182 goto out;
2183 }
2184
2185 /*
2186 * Supplier or supplier's ancestor already initialized without a struct
2187 * device or being probed by a driver.
2188 */
2189 if (fwnode_init_without_drv(sup_handle) ||
2190 fwnode_ancestor_init_without_drv(sup_handle)) {
2191 dev_dbg(con, "Not linking %pfwf - might never become dev\n",
2192 sup_handle);
2193 return -EINVAL;
2194 }
2195
2196 ret = -EAGAIN;
2197out:
2198 put_device(sup_dev);
2199 return ret;
2200}
2201
2202/**
2203 * __fw_devlink_link_to_consumers - Create device links to consumers of a device
2204 * @dev: Device that needs to be linked to its consumers
2205 *
2206 * This function looks at all the consumer fwnodes of @dev and creates device
2207 * links between the consumer device and @dev (supplier).
2208 *
2209 * If the consumer device has not been added yet, then this function creates a
2210 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device
2211 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a
2212 * sync_state() callback before the real consumer device gets to be added and
2213 * then probed.
2214 *
2215 * Once device links are created from the real consumer to @dev (supplier), the
2216 * fwnode links are deleted.
2217 */
2218static void __fw_devlink_link_to_consumers(struct device *dev)
2219{
2220 struct fwnode_handle *fwnode = dev->fwnode;
2221 struct fwnode_link *link, *tmp;
2222
2223 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
2224 struct device *con_dev;
2225 bool own_link = true;
2226 int ret;
2227
2228 con_dev = get_dev_from_fwnode(link->consumer);
2229 /*
2230 * If consumer device is not available yet, make a "proxy"
2231 * SYNC_STATE_ONLY link from the consumer's parent device to
2232 * the supplier device. This is necessary to make sure the
2233 * supplier doesn't get a sync_state() callback before the real
2234 * consumer can create a device link to the supplier.
2235 *
2236 * This proxy link step is needed to handle the case where the
2237 * consumer's parent device is added before the supplier.
2238 */
2239 if (!con_dev) {
2240 con_dev = fwnode_get_next_parent_dev(link->consumer);
2241 /*
2242 * However, if the consumer's parent device is also the
2243 * parent of the supplier, don't create a
2244 * consumer-supplier link from the parent to its child
2245 * device. Such a dependency is impossible.
2246 */
2247 if (con_dev &&
2248 fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) {
2249 put_device(con_dev);
2250 con_dev = NULL;
2251 } else {
2252 own_link = false;
2253 }
2254 }
2255
2256 if (!con_dev)
2257 continue;
2258
2259 ret = fw_devlink_create_devlink(con_dev, fwnode, link);
2260 put_device(con_dev);
2261 if (!own_link || ret == -EAGAIN)
2262 continue;
2263
2264 __fwnode_link_del(link);
2265 }
2266}
2267
2268/**
2269 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device
2270 * @dev: The consumer device that needs to be linked to its suppliers
2271 * @fwnode: Root of the fwnode tree that is used to create device links
2272 *
2273 * This function looks at all the supplier fwnodes of fwnode tree rooted at
2274 * @fwnode and creates device links between @dev (consumer) and all the
2275 * supplier devices of the entire fwnode tree at @fwnode.
2276 *
2277 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
2278 * and the real suppliers of @dev. Once these device links are created, the
2279 * fwnode links are deleted.
2280 *
2281 * In addition, it also looks at all the suppliers of the entire fwnode tree
2282 * because some of the child devices of @dev that have not been added yet
2283 * (because @dev hasn't probed) might already have their suppliers added to
2284 * driver core. So, this function creates SYNC_STATE_ONLY device links between
2285 * @dev (consumer) and these suppliers to make sure they don't execute their
2286 * sync_state() callbacks before these child devices have a chance to create
2287 * their device links. The fwnode links that correspond to the child devices
2288 * aren't delete because they are needed later to create the device links
2289 * between the real consumer and supplier devices.
2290 */
2291static void __fw_devlink_link_to_suppliers(struct device *dev,
2292 struct fwnode_handle *fwnode)
2293{
2294 bool own_link = (dev->fwnode == fwnode);
2295 struct fwnode_link *link, *tmp;
2296 struct fwnode_handle *child = NULL;
2297
2298 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
2299 int ret;
2300 struct fwnode_handle *sup = link->supplier;
2301
2302 ret = fw_devlink_create_devlink(dev, sup, link);
2303 if (!own_link || ret == -EAGAIN)
2304 continue;
2305
2306 __fwnode_link_del(link);
2307 }
2308
2309 /*
2310 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of
2311 * all the descendants. This proxy link step is needed to handle the
2312 * case where the supplier is added before the consumer's parent device
2313 * (@dev).
2314 */
2315 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
2316 __fw_devlink_link_to_suppliers(dev, child);
2317}
2318
2319static void fw_devlink_link_device(struct device *dev)
2320{
2321 struct fwnode_handle *fwnode = dev->fwnode;
2322
2323 if (!fw_devlink_flags)
2324 return;
2325
2326 fw_devlink_parse_fwtree(fwnode);
2327
2328 guard(mutex)(&fwnode_link_lock);
2329
2330 __fw_devlink_link_to_consumers(dev);
2331 __fw_devlink_link_to_suppliers(dev, fwnode);
2332}
2333
2334/* Device links support end. */
2335
2336static struct kobject *dev_kobj;
2337
2338/* /sys/dev/char */
2339static struct kobject *sysfs_dev_char_kobj;
2340
2341/* /sys/dev/block */
2342static struct kobject *sysfs_dev_block_kobj;
2343
2344static DEFINE_MUTEX(device_hotplug_lock);
2345
2346void lock_device_hotplug(void)
2347{
2348 mutex_lock(&device_hotplug_lock);
2349}
2350
2351void unlock_device_hotplug(void)
2352{
2353 mutex_unlock(&device_hotplug_lock);
2354}
2355
2356int lock_device_hotplug_sysfs(void)
2357{
2358 if (mutex_trylock(&device_hotplug_lock))
2359 return 0;
2360
2361 /* Avoid busy looping (5 ms of sleep should do). */
2362 msleep(5);
2363 return restart_syscall();
2364}
2365
2366#ifdef CONFIG_BLOCK
2367static inline int device_is_not_partition(struct device *dev)
2368{
2369 return !(dev->type == &part_type);
2370}
2371#else
2372static inline int device_is_not_partition(struct device *dev)
2373{
2374 return 1;
2375}
2376#endif
2377
2378static void device_platform_notify(struct device *dev)
2379{
2380 acpi_device_notify(dev);
2381
2382 software_node_notify(dev);
2383}
2384
2385static void device_platform_notify_remove(struct device *dev)
2386{
2387 software_node_notify_remove(dev);
2388
2389 acpi_device_notify_remove(dev);
2390}
2391
2392/**
2393 * dev_driver_string - Return a device's driver name, if at all possible
2394 * @dev: struct device to get the name of
2395 *
2396 * Will return the device's driver's name if it is bound to a device. If
2397 * the device is not bound to a driver, it will return the name of the bus
2398 * it is attached to. If it is not attached to a bus either, an empty
2399 * string will be returned.
2400 */
2401const char *dev_driver_string(const struct device *dev)
2402{
2403 struct device_driver *drv;
2404
2405 /* dev->driver can change to NULL underneath us because of unbinding,
2406 * so be careful about accessing it. dev->bus and dev->class should
2407 * never change once they are set, so they don't need special care.
2408 */
2409 drv = READ_ONCE(dev->driver);
2410 return drv ? drv->name : dev_bus_name(dev);
2411}
2412EXPORT_SYMBOL(dev_driver_string);
2413
2414#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
2415
2416static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
2417 char *buf)
2418{
2419 struct device_attribute *dev_attr = to_dev_attr(attr);
2420 struct device *dev = kobj_to_dev(kobj);
2421 ssize_t ret = -EIO;
2422
2423 if (dev_attr->show)
2424 ret = dev_attr->show(dev, dev_attr, buf);
2425 if (ret >= (ssize_t)PAGE_SIZE) {
2426 printk("dev_attr_show: %pS returned bad count\n",
2427 dev_attr->show);
2428 }
2429 return ret;
2430}
2431
2432static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
2433 const char *buf, size_t count)
2434{
2435 struct device_attribute *dev_attr = to_dev_attr(attr);
2436 struct device *dev = kobj_to_dev(kobj);
2437 ssize_t ret = -EIO;
2438
2439 if (dev_attr->store)
2440 ret = dev_attr->store(dev, dev_attr, buf, count);
2441 return ret;
2442}
2443
2444static const struct sysfs_ops dev_sysfs_ops = {
2445 .show = dev_attr_show,
2446 .store = dev_attr_store,
2447};
2448
2449#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
2450
2451ssize_t device_store_ulong(struct device *dev,
2452 struct device_attribute *attr,
2453 const char *buf, size_t size)
2454{
2455 struct dev_ext_attribute *ea = to_ext_attr(attr);
2456 int ret;
2457 unsigned long new;
2458
2459 ret = kstrtoul(buf, 0, &new);
2460 if (ret)
2461 return ret;
2462 *(unsigned long *)(ea->var) = new;
2463 /* Always return full write size even if we didn't consume all */
2464 return size;
2465}
2466EXPORT_SYMBOL_GPL(device_store_ulong);
2467
2468ssize_t device_show_ulong(struct device *dev,
2469 struct device_attribute *attr,
2470 char *buf)
2471{
2472 struct dev_ext_attribute *ea = to_ext_attr(attr);
2473 return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var));
2474}
2475EXPORT_SYMBOL_GPL(device_show_ulong);
2476
2477ssize_t device_store_int(struct device *dev,
2478 struct device_attribute *attr,
2479 const char *buf, size_t size)
2480{
2481 struct dev_ext_attribute *ea = to_ext_attr(attr);
2482 int ret;
2483 long new;
2484
2485 ret = kstrtol(buf, 0, &new);
2486 if (ret)
2487 return ret;
2488
2489 if (new > INT_MAX || new < INT_MIN)
2490 return -EINVAL;
2491 *(int *)(ea->var) = new;
2492 /* Always return full write size even if we didn't consume all */
2493 return size;
2494}
2495EXPORT_SYMBOL_GPL(device_store_int);
2496
2497ssize_t device_show_int(struct device *dev,
2498 struct device_attribute *attr,
2499 char *buf)
2500{
2501 struct dev_ext_attribute *ea = to_ext_attr(attr);
2502
2503 return sysfs_emit(buf, "%d\n", *(int *)(ea->var));
2504}
2505EXPORT_SYMBOL_GPL(device_show_int);
2506
2507ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
2508 const char *buf, size_t size)
2509{
2510 struct dev_ext_attribute *ea = to_ext_attr(attr);
2511
2512 if (kstrtobool(buf, ea->var) < 0)
2513 return -EINVAL;
2514
2515 return size;
2516}
2517EXPORT_SYMBOL_GPL(device_store_bool);
2518
2519ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
2520 char *buf)
2521{
2522 struct dev_ext_attribute *ea = to_ext_attr(attr);
2523
2524 return sysfs_emit(buf, "%d\n", *(bool *)(ea->var));
2525}
2526EXPORT_SYMBOL_GPL(device_show_bool);
2527
2528ssize_t device_show_string(struct device *dev,
2529 struct device_attribute *attr, char *buf)
2530{
2531 struct dev_ext_attribute *ea = to_ext_attr(attr);
2532
2533 return sysfs_emit(buf, "%s\n", (char *)ea->var);
2534}
2535EXPORT_SYMBOL_GPL(device_show_string);
2536
2537/**
2538 * device_release - free device structure.
2539 * @kobj: device's kobject.
2540 *
2541 * This is called once the reference count for the object
2542 * reaches 0. We forward the call to the device's release
2543 * method, which should handle actually freeing the structure.
2544 */
2545static void device_release(struct kobject *kobj)
2546{
2547 struct device *dev = kobj_to_dev(kobj);
2548 struct device_private *p = dev->p;
2549
2550 /*
2551 * Some platform devices are driven without driver attached
2552 * and managed resources may have been acquired. Make sure
2553 * all resources are released.
2554 *
2555 * Drivers still can add resources into device after device
2556 * is deleted but alive, so release devres here to avoid
2557 * possible memory leak.
2558 */
2559 devres_release_all(dev);
2560
2561 kfree(dev->dma_range_map);
2562
2563 if (dev->release)
2564 dev->release(dev);
2565 else if (dev->type && dev->type->release)
2566 dev->type->release(dev);
2567 else if (dev->class && dev->class->dev_release)
2568 dev->class->dev_release(dev);
2569 else
2570 WARN(1, KERN_ERR "Device '%s' does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
2571 dev_name(dev));
2572 kfree(p);
2573}
2574
2575static const void *device_namespace(const struct kobject *kobj)
2576{
2577 const struct device *dev = kobj_to_dev(kobj);
2578 const void *ns = NULL;
2579
2580 if (dev->class && dev->class->namespace)
2581 ns = dev->class->namespace(dev);
2582
2583 return ns;
2584}
2585
2586static void device_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
2587{
2588 const struct device *dev = kobj_to_dev(kobj);
2589
2590 if (dev->class && dev->class->get_ownership)
2591 dev->class->get_ownership(dev, uid, gid);
2592}
2593
2594static const struct kobj_type device_ktype = {
2595 .release = device_release,
2596 .sysfs_ops = &dev_sysfs_ops,
2597 .namespace = device_namespace,
2598 .get_ownership = device_get_ownership,
2599};
2600
2601
2602static int dev_uevent_filter(const struct kobject *kobj)
2603{
2604 const struct kobj_type *ktype = get_ktype(kobj);
2605
2606 if (ktype == &device_ktype) {
2607 const struct device *dev = kobj_to_dev(kobj);
2608 if (dev->bus)
2609 return 1;
2610 if (dev->class)
2611 return 1;
2612 }
2613 return 0;
2614}
2615
2616static const char *dev_uevent_name(const struct kobject *kobj)
2617{
2618 const struct device *dev = kobj_to_dev(kobj);
2619
2620 if (dev->bus)
2621 return dev->bus->name;
2622 if (dev->class)
2623 return dev->class->name;
2624 return NULL;
2625}
2626
2627static int dev_uevent(const struct kobject *kobj, struct kobj_uevent_env *env)
2628{
2629 const struct device *dev = kobj_to_dev(kobj);
2630 int retval = 0;
2631
2632 /* add device node properties if present */
2633 if (MAJOR(dev->devt)) {
2634 const char *tmp;
2635 const char *name;
2636 umode_t mode = 0;
2637 kuid_t uid = GLOBAL_ROOT_UID;
2638 kgid_t gid = GLOBAL_ROOT_GID;
2639
2640 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
2641 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
2642 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
2643 if (name) {
2644 add_uevent_var(env, "DEVNAME=%s", name);
2645 if (mode)
2646 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
2647 if (!uid_eq(uid, GLOBAL_ROOT_UID))
2648 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
2649 if (!gid_eq(gid, GLOBAL_ROOT_GID))
2650 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
2651 kfree(tmp);
2652 }
2653 }
2654
2655 if (dev->type && dev->type->name)
2656 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
2657
2658 if (dev->driver)
2659 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
2660
2661 /* Add common DT information about the device */
2662 of_device_uevent(dev, env);
2663
2664 /* have the bus specific function add its stuff */
2665 if (dev->bus && dev->bus->uevent) {
2666 retval = dev->bus->uevent(dev, env);
2667 if (retval)
2668 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
2669 dev_name(dev), __func__, retval);
2670 }
2671
2672 /* have the class specific function add its stuff */
2673 if (dev->class && dev->class->dev_uevent) {
2674 retval = dev->class->dev_uevent(dev, env);
2675 if (retval)
2676 pr_debug("device: '%s': %s: class uevent() "
2677 "returned %d\n", dev_name(dev),
2678 __func__, retval);
2679 }
2680
2681 /* have the device type specific function add its stuff */
2682 if (dev->type && dev->type->uevent) {
2683 retval = dev->type->uevent(dev, env);
2684 if (retval)
2685 pr_debug("device: '%s': %s: dev_type uevent() "
2686 "returned %d\n", dev_name(dev),
2687 __func__, retval);
2688 }
2689
2690 return retval;
2691}
2692
2693static const struct kset_uevent_ops device_uevent_ops = {
2694 .filter = dev_uevent_filter,
2695 .name = dev_uevent_name,
2696 .uevent = dev_uevent,
2697};
2698
2699static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
2700 char *buf)
2701{
2702 struct kobject *top_kobj;
2703 struct kset *kset;
2704 struct kobj_uevent_env *env = NULL;
2705 int i;
2706 int len = 0;
2707 int retval;
2708
2709 /* search the kset, the device belongs to */
2710 top_kobj = &dev->kobj;
2711 while (!top_kobj->kset && top_kobj->parent)
2712 top_kobj = top_kobj->parent;
2713 if (!top_kobj->kset)
2714 goto out;
2715
2716 kset = top_kobj->kset;
2717 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
2718 goto out;
2719
2720 /* respect filter */
2721 if (kset->uevent_ops && kset->uevent_ops->filter)
2722 if (!kset->uevent_ops->filter(&dev->kobj))
2723 goto out;
2724
2725 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
2726 if (!env)
2727 return -ENOMEM;
2728
2729 /* Synchronize with really_probe() */
2730 device_lock(dev);
2731 /* let the kset specific function add its keys */
2732 retval = kset->uevent_ops->uevent(&dev->kobj, env);
2733 device_unlock(dev);
2734 if (retval)
2735 goto out;
2736
2737 /* copy keys to file */
2738 for (i = 0; i < env->envp_idx; i++)
2739 len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]);
2740out:
2741 kfree(env);
2742 return len;
2743}
2744
2745static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
2746 const char *buf, size_t count)
2747{
2748 int rc;
2749
2750 rc = kobject_synth_uevent(&dev->kobj, buf, count);
2751
2752 if (rc) {
2753 dev_err(dev, "uevent: failed to send synthetic uevent: %d\n", rc);
2754 return rc;
2755 }
2756
2757 return count;
2758}
2759static DEVICE_ATTR_RW(uevent);
2760
2761static ssize_t online_show(struct device *dev, struct device_attribute *attr,
2762 char *buf)
2763{
2764 bool val;
2765
2766 device_lock(dev);
2767 val = !dev->offline;
2768 device_unlock(dev);
2769 return sysfs_emit(buf, "%u\n", val);
2770}
2771
2772static ssize_t online_store(struct device *dev, struct device_attribute *attr,
2773 const char *buf, size_t count)
2774{
2775 bool val;
2776 int ret;
2777
2778 ret = kstrtobool(buf, &val);
2779 if (ret < 0)
2780 return ret;
2781
2782 ret = lock_device_hotplug_sysfs();
2783 if (ret)
2784 return ret;
2785
2786 ret = val ? device_online(dev) : device_offline(dev);
2787 unlock_device_hotplug();
2788 return ret < 0 ? ret : count;
2789}
2790static DEVICE_ATTR_RW(online);
2791
2792static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
2793 char *buf)
2794{
2795 const char *loc;
2796
2797 switch (dev->removable) {
2798 case DEVICE_REMOVABLE:
2799 loc = "removable";
2800 break;
2801 case DEVICE_FIXED:
2802 loc = "fixed";
2803 break;
2804 default:
2805 loc = "unknown";
2806 }
2807 return sysfs_emit(buf, "%s\n", loc);
2808}
2809static DEVICE_ATTR_RO(removable);
2810
2811int device_add_groups(struct device *dev, const struct attribute_group **groups)
2812{
2813 return sysfs_create_groups(&dev->kobj, groups);
2814}
2815EXPORT_SYMBOL_GPL(device_add_groups);
2816
2817void device_remove_groups(struct device *dev,
2818 const struct attribute_group **groups)
2819{
2820 sysfs_remove_groups(&dev->kobj, groups);
2821}
2822EXPORT_SYMBOL_GPL(device_remove_groups);
2823
2824union device_attr_group_devres {
2825 const struct attribute_group *group;
2826 const struct attribute_group **groups;
2827};
2828
2829static void devm_attr_group_remove(struct device *dev, void *res)
2830{
2831 union device_attr_group_devres *devres = res;
2832 const struct attribute_group *group = devres->group;
2833
2834 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2835 sysfs_remove_group(&dev->kobj, group);
2836}
2837
2838/**
2839 * devm_device_add_group - given a device, create a managed attribute group
2840 * @dev: The device to create the group for
2841 * @grp: The attribute group to create
2842 *
2843 * This function creates a group for the first time. It will explicitly
2844 * warn and error if any of the attribute files being created already exist.
2845 *
2846 * Returns 0 on success or error code on failure.
2847 */
2848int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2849{
2850 union device_attr_group_devres *devres;
2851 int error;
2852
2853 devres = devres_alloc(devm_attr_group_remove,
2854 sizeof(*devres), GFP_KERNEL);
2855 if (!devres)
2856 return -ENOMEM;
2857
2858 error = sysfs_create_group(&dev->kobj, grp);
2859 if (error) {
2860 devres_free(devres);
2861 return error;
2862 }
2863
2864 devres->group = grp;
2865 devres_add(dev, devres);
2866 return 0;
2867}
2868EXPORT_SYMBOL_GPL(devm_device_add_group);
2869
2870static int device_add_attrs(struct device *dev)
2871{
2872 const struct class *class = dev->class;
2873 const struct device_type *type = dev->type;
2874 int error;
2875
2876 if (class) {
2877 error = device_add_groups(dev, class->dev_groups);
2878 if (error)
2879 return error;
2880 }
2881
2882 if (type) {
2883 error = device_add_groups(dev, type->groups);
2884 if (error)
2885 goto err_remove_class_groups;
2886 }
2887
2888 error = device_add_groups(dev, dev->groups);
2889 if (error)
2890 goto err_remove_type_groups;
2891
2892 if (device_supports_offline(dev) && !dev->offline_disabled) {
2893 error = device_create_file(dev, &dev_attr_online);
2894 if (error)
2895 goto err_remove_dev_groups;
2896 }
2897
2898 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
2899 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2900 if (error)
2901 goto err_remove_dev_online;
2902 }
2903
2904 if (dev_removable_is_valid(dev)) {
2905 error = device_create_file(dev, &dev_attr_removable);
2906 if (error)
2907 goto err_remove_dev_waiting_for_supplier;
2908 }
2909
2910 if (dev_add_physical_location(dev)) {
2911 error = device_add_group(dev,
2912 &dev_attr_physical_location_group);
2913 if (error)
2914 goto err_remove_dev_removable;
2915 }
2916
2917 return 0;
2918
2919 err_remove_dev_removable:
2920 device_remove_file(dev, &dev_attr_removable);
2921 err_remove_dev_waiting_for_supplier:
2922 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2923 err_remove_dev_online:
2924 device_remove_file(dev, &dev_attr_online);
2925 err_remove_dev_groups:
2926 device_remove_groups(dev, dev->groups);
2927 err_remove_type_groups:
2928 if (type)
2929 device_remove_groups(dev, type->groups);
2930 err_remove_class_groups:
2931 if (class)
2932 device_remove_groups(dev, class->dev_groups);
2933
2934 return error;
2935}
2936
2937static void device_remove_attrs(struct device *dev)
2938{
2939 const struct class *class = dev->class;
2940 const struct device_type *type = dev->type;
2941
2942 if (dev->physical_location) {
2943 device_remove_group(dev, &dev_attr_physical_location_group);
2944 kfree(dev->physical_location);
2945 }
2946
2947 device_remove_file(dev, &dev_attr_removable);
2948 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2949 device_remove_file(dev, &dev_attr_online);
2950 device_remove_groups(dev, dev->groups);
2951
2952 if (type)
2953 device_remove_groups(dev, type->groups);
2954
2955 if (class)
2956 device_remove_groups(dev, class->dev_groups);
2957}
2958
2959static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2960 char *buf)
2961{
2962 return print_dev_t(buf, dev->devt);
2963}
2964static DEVICE_ATTR_RO(dev);
2965
2966/* /sys/devices/ */
2967struct kset *devices_kset;
2968
2969/**
2970 * devices_kset_move_before - Move device in the devices_kset's list.
2971 * @deva: Device to move.
2972 * @devb: Device @deva should come before.
2973 */
2974static void devices_kset_move_before(struct device *deva, struct device *devb)
2975{
2976 if (!devices_kset)
2977 return;
2978 pr_debug("devices_kset: Moving %s before %s\n",
2979 dev_name(deva), dev_name(devb));
2980 spin_lock(&devices_kset->list_lock);
2981 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2982 spin_unlock(&devices_kset->list_lock);
2983}
2984
2985/**
2986 * devices_kset_move_after - Move device in the devices_kset's list.
2987 * @deva: Device to move
2988 * @devb: Device @deva should come after.
2989 */
2990static void devices_kset_move_after(struct device *deva, struct device *devb)
2991{
2992 if (!devices_kset)
2993 return;
2994 pr_debug("devices_kset: Moving %s after %s\n",
2995 dev_name(deva), dev_name(devb));
2996 spin_lock(&devices_kset->list_lock);
2997 list_move(&deva->kobj.entry, &devb->kobj.entry);
2998 spin_unlock(&devices_kset->list_lock);
2999}
3000
3001/**
3002 * devices_kset_move_last - move the device to the end of devices_kset's list.
3003 * @dev: device to move
3004 */
3005void devices_kset_move_last(struct device *dev)
3006{
3007 if (!devices_kset)
3008 return;
3009 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
3010 spin_lock(&devices_kset->list_lock);
3011 list_move_tail(&dev->kobj.entry, &devices_kset->list);
3012 spin_unlock(&devices_kset->list_lock);
3013}
3014
3015/**
3016 * device_create_file - create sysfs attribute file for device.
3017 * @dev: device.
3018 * @attr: device attribute descriptor.
3019 */
3020int device_create_file(struct device *dev,
3021 const struct device_attribute *attr)
3022{
3023 int error = 0;
3024
3025 if (dev) {
3026 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
3027 "Attribute %s: write permission without 'store'\n",
3028 attr->attr.name);
3029 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
3030 "Attribute %s: read permission without 'show'\n",
3031 attr->attr.name);
3032 error = sysfs_create_file(&dev->kobj, &attr->attr);
3033 }
3034
3035 return error;
3036}
3037EXPORT_SYMBOL_GPL(device_create_file);
3038
3039/**
3040 * device_remove_file - remove sysfs attribute file.
3041 * @dev: device.
3042 * @attr: device attribute descriptor.
3043 */
3044void device_remove_file(struct device *dev,
3045 const struct device_attribute *attr)
3046{
3047 if (dev)
3048 sysfs_remove_file(&dev->kobj, &attr->attr);
3049}
3050EXPORT_SYMBOL_GPL(device_remove_file);
3051
3052/**
3053 * device_remove_file_self - remove sysfs attribute file from its own method.
3054 * @dev: device.
3055 * @attr: device attribute descriptor.
3056 *
3057 * See kernfs_remove_self() for details.
3058 */
3059bool device_remove_file_self(struct device *dev,
3060 const struct device_attribute *attr)
3061{
3062 if (dev)
3063 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
3064 else
3065 return false;
3066}
3067EXPORT_SYMBOL_GPL(device_remove_file_self);
3068
3069/**
3070 * device_create_bin_file - create sysfs binary attribute file for device.
3071 * @dev: device.
3072 * @attr: device binary attribute descriptor.
3073 */
3074int device_create_bin_file(struct device *dev,
3075 const struct bin_attribute *attr)
3076{
3077 int error = -EINVAL;
3078 if (dev)
3079 error = sysfs_create_bin_file(&dev->kobj, attr);
3080 return error;
3081}
3082EXPORT_SYMBOL_GPL(device_create_bin_file);
3083
3084/**
3085 * device_remove_bin_file - remove sysfs binary attribute file
3086 * @dev: device.
3087 * @attr: device binary attribute descriptor.
3088 */
3089void device_remove_bin_file(struct device *dev,
3090 const struct bin_attribute *attr)
3091{
3092 if (dev)
3093 sysfs_remove_bin_file(&dev->kobj, attr);
3094}
3095EXPORT_SYMBOL_GPL(device_remove_bin_file);
3096
3097static void klist_children_get(struct klist_node *n)
3098{
3099 struct device_private *p = to_device_private_parent(n);
3100 struct device *dev = p->device;
3101
3102 get_device(dev);
3103}
3104
3105static void klist_children_put(struct klist_node *n)
3106{
3107 struct device_private *p = to_device_private_parent(n);
3108 struct device *dev = p->device;
3109
3110 put_device(dev);
3111}
3112
3113/**
3114 * device_initialize - init device structure.
3115 * @dev: device.
3116 *
3117 * This prepares the device for use by other layers by initializing
3118 * its fields.
3119 * It is the first half of device_register(), if called by
3120 * that function, though it can also be called separately, so one
3121 * may use @dev's fields. In particular, get_device()/put_device()
3122 * may be used for reference counting of @dev after calling this
3123 * function.
3124 *
3125 * All fields in @dev must be initialized by the caller to 0, except
3126 * for those explicitly set to some other value. The simplest
3127 * approach is to use kzalloc() to allocate the structure containing
3128 * @dev.
3129 *
3130 * NOTE: Use put_device() to give up your reference instead of freeing
3131 * @dev directly once you have called this function.
3132 */
3133void device_initialize(struct device *dev)
3134{
3135 dev->kobj.kset = devices_kset;
3136 kobject_init(&dev->kobj, &device_ktype);
3137 INIT_LIST_HEAD(&dev->dma_pools);
3138 mutex_init(&dev->mutex);
3139 lockdep_set_novalidate_class(&dev->mutex);
3140 spin_lock_init(&dev->devres_lock);
3141 INIT_LIST_HEAD(&dev->devres_head);
3142 device_pm_init(dev);
3143 set_dev_node(dev, NUMA_NO_NODE);
3144 INIT_LIST_HEAD(&dev->links.consumers);
3145 INIT_LIST_HEAD(&dev->links.suppliers);
3146 INIT_LIST_HEAD(&dev->links.defer_sync);
3147 dev->links.status = DL_DEV_NO_DRIVER;
3148#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
3149 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
3150 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
3151 dev->dma_coherent = dma_default_coherent;
3152#endif
3153 swiotlb_dev_init(dev);
3154}
3155EXPORT_SYMBOL_GPL(device_initialize);
3156
3157struct kobject *virtual_device_parent(void)
3158{
3159 static struct kobject *virtual_dir = NULL;
3160
3161 if (!virtual_dir)
3162 virtual_dir = kobject_create_and_add("virtual",
3163 &devices_kset->kobj);
3164
3165 return virtual_dir;
3166}
3167
3168struct class_dir {
3169 struct kobject kobj;
3170 const struct class *class;
3171};
3172
3173#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
3174
3175static void class_dir_release(struct kobject *kobj)
3176{
3177 struct class_dir *dir = to_class_dir(kobj);
3178 kfree(dir);
3179}
3180
3181static const
3182struct kobj_ns_type_operations *class_dir_child_ns_type(const struct kobject *kobj)
3183{
3184 const struct class_dir *dir = to_class_dir(kobj);
3185 return dir->class->ns_type;
3186}
3187
3188static const struct kobj_type class_dir_ktype = {
3189 .release = class_dir_release,
3190 .sysfs_ops = &kobj_sysfs_ops,
3191 .child_ns_type = class_dir_child_ns_type
3192};
3193
3194static struct kobject *class_dir_create_and_add(struct subsys_private *sp,
3195 struct kobject *parent_kobj)
3196{
3197 struct class_dir *dir;
3198 int retval;
3199
3200 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
3201 if (!dir)
3202 return ERR_PTR(-ENOMEM);
3203
3204 dir->class = sp->class;
3205 kobject_init(&dir->kobj, &class_dir_ktype);
3206
3207 dir->kobj.kset = &sp->glue_dirs;
3208
3209 retval = kobject_add(&dir->kobj, parent_kobj, "%s", sp->class->name);
3210 if (retval < 0) {
3211 kobject_put(&dir->kobj);
3212 return ERR_PTR(retval);
3213 }
3214 return &dir->kobj;
3215}
3216
3217static DEFINE_MUTEX(gdp_mutex);
3218
3219static struct kobject *get_device_parent(struct device *dev,
3220 struct device *parent)
3221{
3222 struct subsys_private *sp = class_to_subsys(dev->class);
3223 struct kobject *kobj = NULL;
3224
3225 if (sp) {
3226 struct kobject *parent_kobj;
3227 struct kobject *k;
3228
3229 /*
3230 * If we have no parent, we live in "virtual".
3231 * Class-devices with a non class-device as parent, live
3232 * in a "glue" directory to prevent namespace collisions.
3233 */
3234 if (parent == NULL)
3235 parent_kobj = virtual_device_parent();
3236 else if (parent->class && !dev->class->ns_type) {
3237 subsys_put(sp);
3238 return &parent->kobj;
3239 } else {
3240 parent_kobj = &parent->kobj;
3241 }
3242
3243 mutex_lock(&gdp_mutex);
3244
3245 /* find our class-directory at the parent and reference it */
3246 spin_lock(&sp->glue_dirs.list_lock);
3247 list_for_each_entry(k, &sp->glue_dirs.list, entry)
3248 if (k->parent == parent_kobj) {
3249 kobj = kobject_get(k);
3250 break;
3251 }
3252 spin_unlock(&sp->glue_dirs.list_lock);
3253 if (kobj) {
3254 mutex_unlock(&gdp_mutex);
3255 subsys_put(sp);
3256 return kobj;
3257 }
3258
3259 /* or create a new class-directory at the parent device */
3260 k = class_dir_create_and_add(sp, parent_kobj);
3261 /* do not emit an uevent for this simple "glue" directory */
3262 mutex_unlock(&gdp_mutex);
3263 subsys_put(sp);
3264 return k;
3265 }
3266
3267 /* subsystems can specify a default root directory for their devices */
3268 if (!parent && dev->bus) {
3269 struct device *dev_root = bus_get_dev_root(dev->bus);
3270
3271 if (dev_root) {
3272 kobj = &dev_root->kobj;
3273 put_device(dev_root);
3274 return kobj;
3275 }
3276 }
3277
3278 if (parent)
3279 return &parent->kobj;
3280 return NULL;
3281}
3282
3283static inline bool live_in_glue_dir(struct kobject *kobj,
3284 struct device *dev)
3285{
3286 struct subsys_private *sp;
3287 bool retval;
3288
3289 if (!kobj || !dev->class)
3290 return false;
3291
3292 sp = class_to_subsys(dev->class);
3293 if (!sp)
3294 return false;
3295
3296 if (kobj->kset == &sp->glue_dirs)
3297 retval = true;
3298 else
3299 retval = false;
3300
3301 subsys_put(sp);
3302 return retval;
3303}
3304
3305static inline struct kobject *get_glue_dir(struct device *dev)
3306{
3307 return dev->kobj.parent;
3308}
3309
3310/**
3311 * kobject_has_children - Returns whether a kobject has children.
3312 * @kobj: the object to test
3313 *
3314 * This will return whether a kobject has other kobjects as children.
3315 *
3316 * It does NOT account for the presence of attribute files, only sub
3317 * directories. It also assumes there is no concurrent addition or
3318 * removal of such children, and thus relies on external locking.
3319 */
3320static inline bool kobject_has_children(struct kobject *kobj)
3321{
3322 WARN_ON_ONCE(kref_read(&kobj->kref) == 0);
3323
3324 return kobj->sd && kobj->sd->dir.subdirs;
3325}
3326
3327/*
3328 * make sure cleaning up dir as the last step, we need to make
3329 * sure .release handler of kobject is run with holding the
3330 * global lock
3331 */
3332static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
3333{
3334 unsigned int ref;
3335
3336 /* see if we live in a "glue" directory */
3337 if (!live_in_glue_dir(glue_dir, dev))
3338 return;
3339
3340 mutex_lock(&gdp_mutex);
3341 /**
3342 * There is a race condition between removing glue directory
3343 * and adding a new device under the glue directory.
3344 *
3345 * CPU1: CPU2:
3346 *
3347 * device_add()
3348 * get_device_parent()
3349 * class_dir_create_and_add()
3350 * kobject_add_internal()
3351 * create_dir() // create glue_dir
3352 *
3353 * device_add()
3354 * get_device_parent()
3355 * kobject_get() // get glue_dir
3356 *
3357 * device_del()
3358 * cleanup_glue_dir()
3359 * kobject_del(glue_dir)
3360 *
3361 * kobject_add()
3362 * kobject_add_internal()
3363 * create_dir() // in glue_dir
3364 * sysfs_create_dir_ns()
3365 * kernfs_create_dir_ns(sd)
3366 *
3367 * sysfs_remove_dir() // glue_dir->sd=NULL
3368 * sysfs_put() // free glue_dir->sd
3369 *
3370 * // sd is freed
3371 * kernfs_new_node(sd)
3372 * kernfs_get(glue_dir)
3373 * kernfs_add_one()
3374 * kernfs_put()
3375 *
3376 * Before CPU1 remove last child device under glue dir, if CPU2 add
3377 * a new device under glue dir, the glue_dir kobject reference count
3378 * will be increase to 2 in kobject_get(k). And CPU2 has been called
3379 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
3380 * and sysfs_put(). This result in glue_dir->sd is freed.
3381 *
3382 * Then the CPU2 will see a stale "empty" but still potentially used
3383 * glue dir around in kernfs_new_node().
3384 *
3385 * In order to avoid this happening, we also should make sure that
3386 * kernfs_node for glue_dir is released in CPU1 only when refcount
3387 * for glue_dir kobj is 1.
3388 */
3389 ref = kref_read(&glue_dir->kref);
3390 if (!kobject_has_children(glue_dir) && !--ref)
3391 kobject_del(glue_dir);
3392 kobject_put(glue_dir);
3393 mutex_unlock(&gdp_mutex);
3394}
3395
3396static int device_add_class_symlinks(struct device *dev)
3397{
3398 struct device_node *of_node = dev_of_node(dev);
3399 struct subsys_private *sp;
3400 int error;
3401
3402 if (of_node) {
3403 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
3404 if (error)
3405 dev_warn(dev, "Error %d creating of_node link\n",error);
3406 /* An error here doesn't warrant bringing down the device */
3407 }
3408
3409 sp = class_to_subsys(dev->class);
3410 if (!sp)
3411 return 0;
3412
3413 error = sysfs_create_link(&dev->kobj, &sp->subsys.kobj, "subsystem");
3414 if (error)
3415 goto out_devnode;
3416
3417 if (dev->parent && device_is_not_partition(dev)) {
3418 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
3419 "device");
3420 if (error)
3421 goto out_subsys;
3422 }
3423
3424 /* link in the class directory pointing to the device */
3425 error = sysfs_create_link(&sp->subsys.kobj, &dev->kobj, dev_name(dev));
3426 if (error)
3427 goto out_device;
3428 goto exit;
3429
3430out_device:
3431 sysfs_remove_link(&dev->kobj, "device");
3432out_subsys:
3433 sysfs_remove_link(&dev->kobj, "subsystem");
3434out_devnode:
3435 sysfs_remove_link(&dev->kobj, "of_node");
3436exit:
3437 subsys_put(sp);
3438 return error;
3439}
3440
3441static void device_remove_class_symlinks(struct device *dev)
3442{
3443 struct subsys_private *sp = class_to_subsys(dev->class);
3444
3445 if (dev_of_node(dev))
3446 sysfs_remove_link(&dev->kobj, "of_node");
3447
3448 if (!sp)
3449 return;
3450
3451 if (dev->parent && device_is_not_partition(dev))
3452 sysfs_remove_link(&dev->kobj, "device");
3453 sysfs_remove_link(&dev->kobj, "subsystem");
3454 sysfs_delete_link(&sp->subsys.kobj, &dev->kobj, dev_name(dev));
3455 subsys_put(sp);
3456}
3457
3458/**
3459 * dev_set_name - set a device name
3460 * @dev: device
3461 * @fmt: format string for the device's name
3462 */
3463int dev_set_name(struct device *dev, const char *fmt, ...)
3464{
3465 va_list vargs;
3466 int err;
3467
3468 va_start(vargs, fmt);
3469 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
3470 va_end(vargs);
3471 return err;
3472}
3473EXPORT_SYMBOL_GPL(dev_set_name);
3474
3475/* select a /sys/dev/ directory for the device */
3476static struct kobject *device_to_dev_kobj(struct device *dev)
3477{
3478 if (is_blockdev(dev))
3479 return sysfs_dev_block_kobj;
3480 else
3481 return sysfs_dev_char_kobj;
3482}
3483
3484static int device_create_sys_dev_entry(struct device *dev)
3485{
3486 struct kobject *kobj = device_to_dev_kobj(dev);
3487 int error = 0;
3488 char devt_str[15];
3489
3490 if (kobj) {
3491 format_dev_t(devt_str, dev->devt);
3492 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
3493 }
3494
3495 return error;
3496}
3497
3498static void device_remove_sys_dev_entry(struct device *dev)
3499{
3500 struct kobject *kobj = device_to_dev_kobj(dev);
3501 char devt_str[15];
3502
3503 if (kobj) {
3504 format_dev_t(devt_str, dev->devt);
3505 sysfs_remove_link(kobj, devt_str);
3506 }
3507}
3508
3509static int device_private_init(struct device *dev)
3510{
3511 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
3512 if (!dev->p)
3513 return -ENOMEM;
3514 dev->p->device = dev;
3515 klist_init(&dev->p->klist_children, klist_children_get,
3516 klist_children_put);
3517 INIT_LIST_HEAD(&dev->p->deferred_probe);
3518 return 0;
3519}
3520
3521/**
3522 * device_add - add device to device hierarchy.
3523 * @dev: device.
3524 *
3525 * This is part 2 of device_register(), though may be called
3526 * separately _iff_ device_initialize() has been called separately.
3527 *
3528 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
3529 * to the global and sibling lists for the device, then
3530 * adds it to the other relevant subsystems of the driver model.
3531 *
3532 * Do not call this routine or device_register() more than once for
3533 * any device structure. The driver model core is not designed to work
3534 * with devices that get unregistered and then spring back to life.
3535 * (Among other things, it's very hard to guarantee that all references
3536 * to the previous incarnation of @dev have been dropped.) Allocate
3537 * and register a fresh new struct device instead.
3538 *
3539 * NOTE: _Never_ directly free @dev after calling this function, even
3540 * if it returned an error! Always use put_device() to give up your
3541 * reference instead.
3542 *
3543 * Rule of thumb is: if device_add() succeeds, you should call
3544 * device_del() when you want to get rid of it. If device_add() has
3545 * *not* succeeded, use *only* put_device() to drop the reference
3546 * count.
3547 */
3548int device_add(struct device *dev)
3549{
3550 struct subsys_private *sp;
3551 struct device *parent;
3552 struct kobject *kobj;
3553 struct class_interface *class_intf;
3554 int error = -EINVAL;
3555 struct kobject *glue_dir = NULL;
3556
3557 dev = get_device(dev);
3558 if (!dev)
3559 goto done;
3560
3561 if (!dev->p) {
3562 error = device_private_init(dev);
3563 if (error)
3564 goto done;
3565 }
3566
3567 /*
3568 * for statically allocated devices, which should all be converted
3569 * some day, we need to initialize the name. We prevent reading back
3570 * the name, and force the use of dev_name()
3571 */
3572 if (dev->init_name) {
3573 error = dev_set_name(dev, "%s", dev->init_name);
3574 dev->init_name = NULL;
3575 }
3576
3577 if (dev_name(dev))
3578 error = 0;
3579 /* subsystems can specify simple device enumeration */
3580 else if (dev->bus && dev->bus->dev_name)
3581 error = dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
3582 else
3583 error = -EINVAL;
3584 if (error)
3585 goto name_error;
3586
3587 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3588
3589 parent = get_device(dev->parent);
3590 kobj = get_device_parent(dev, parent);
3591 if (IS_ERR(kobj)) {
3592 error = PTR_ERR(kobj);
3593 goto parent_error;
3594 }
3595 if (kobj)
3596 dev->kobj.parent = kobj;
3597
3598 /* use parent numa_node */
3599 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
3600 set_dev_node(dev, dev_to_node(parent));
3601
3602 /* first, register with generic layer. */
3603 /* we require the name to be set before, and pass NULL */
3604 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
3605 if (error) {
3606 glue_dir = kobj;
3607 goto Error;
3608 }
3609
3610 /* notify platform of device entry */
3611 device_platform_notify(dev);
3612
3613 error = device_create_file(dev, &dev_attr_uevent);
3614 if (error)
3615 goto attrError;
3616
3617 error = device_add_class_symlinks(dev);
3618 if (error)
3619 goto SymlinkError;
3620 error = device_add_attrs(dev);
3621 if (error)
3622 goto AttrsError;
3623 error = bus_add_device(dev);
3624 if (error)
3625 goto BusError;
3626 error = dpm_sysfs_add(dev);
3627 if (error)
3628 goto DPMError;
3629 device_pm_add(dev);
3630
3631 if (MAJOR(dev->devt)) {
3632 error = device_create_file(dev, &dev_attr_dev);
3633 if (error)
3634 goto DevAttrError;
3635
3636 error = device_create_sys_dev_entry(dev);
3637 if (error)
3638 goto SysEntryError;
3639
3640 devtmpfs_create_node(dev);
3641 }
3642
3643 /* Notify clients of device addition. This call must come
3644 * after dpm_sysfs_add() and before kobject_uevent().
3645 */
3646 bus_notify(dev, BUS_NOTIFY_ADD_DEVICE);
3647 kobject_uevent(&dev->kobj, KOBJ_ADD);
3648
3649 /*
3650 * Check if any of the other devices (consumers) have been waiting for
3651 * this device (supplier) to be added so that they can create a device
3652 * link to it.
3653 *
3654 * This needs to happen after device_pm_add() because device_link_add()
3655 * requires the supplier be registered before it's called.
3656 *
3657 * But this also needs to happen before bus_probe_device() to make sure
3658 * waiting consumers can link to it before the driver is bound to the
3659 * device and the driver sync_state callback is called for this device.
3660 */
3661 if (dev->fwnode && !dev->fwnode->dev) {
3662 dev->fwnode->dev = dev;
3663 fw_devlink_link_device(dev);
3664 }
3665
3666 bus_probe_device(dev);
3667
3668 /*
3669 * If all driver registration is done and a newly added device doesn't
3670 * match with any driver, don't block its consumers from probing in
3671 * case the consumer device is able to operate without this supplier.
3672 */
3673 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
3674 fw_devlink_unblock_consumers(dev);
3675
3676 if (parent)
3677 klist_add_tail(&dev->p->knode_parent,
3678 &parent->p->klist_children);
3679
3680 sp = class_to_subsys(dev->class);
3681 if (sp) {
3682 mutex_lock(&sp->mutex);
3683 /* tie the class to the device */
3684 klist_add_tail(&dev->p->knode_class, &sp->klist_devices);
3685
3686 /* notify any interfaces that the device is here */
3687 list_for_each_entry(class_intf, &sp->interfaces, node)
3688 if (class_intf->add_dev)
3689 class_intf->add_dev(dev);
3690 mutex_unlock(&sp->mutex);
3691 subsys_put(sp);
3692 }
3693done:
3694 put_device(dev);
3695 return error;
3696 SysEntryError:
3697 if (MAJOR(dev->devt))
3698 device_remove_file(dev, &dev_attr_dev);
3699 DevAttrError:
3700 device_pm_remove(dev);
3701 dpm_sysfs_remove(dev);
3702 DPMError:
3703 dev->driver = NULL;
3704 bus_remove_device(dev);
3705 BusError:
3706 device_remove_attrs(dev);
3707 AttrsError:
3708 device_remove_class_symlinks(dev);
3709 SymlinkError:
3710 device_remove_file(dev, &dev_attr_uevent);
3711 attrError:
3712 device_platform_notify_remove(dev);
3713 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3714 glue_dir = get_glue_dir(dev);
3715 kobject_del(&dev->kobj);
3716 Error:
3717 cleanup_glue_dir(dev, glue_dir);
3718parent_error:
3719 put_device(parent);
3720name_error:
3721 kfree(dev->p);
3722 dev->p = NULL;
3723 goto done;
3724}
3725EXPORT_SYMBOL_GPL(device_add);
3726
3727/**
3728 * device_register - register a device with the system.
3729 * @dev: pointer to the device structure
3730 *
3731 * This happens in two clean steps - initialize the device
3732 * and add it to the system. The two steps can be called
3733 * separately, but this is the easiest and most common.
3734 * I.e. you should only call the two helpers separately if
3735 * have a clearly defined need to use and refcount the device
3736 * before it is added to the hierarchy.
3737 *
3738 * For more information, see the kerneldoc for device_initialize()
3739 * and device_add().
3740 *
3741 * NOTE: _Never_ directly free @dev after calling this function, even
3742 * if it returned an error! Always use put_device() to give up the
3743 * reference initialized in this function instead.
3744 */
3745int device_register(struct device *dev)
3746{
3747 device_initialize(dev);
3748 return device_add(dev);
3749}
3750EXPORT_SYMBOL_GPL(device_register);
3751
3752/**
3753 * get_device - increment reference count for device.
3754 * @dev: device.
3755 *
3756 * This simply forwards the call to kobject_get(), though
3757 * we do take care to provide for the case that we get a NULL
3758 * pointer passed in.
3759 */
3760struct device *get_device(struct device *dev)
3761{
3762 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3763}
3764EXPORT_SYMBOL_GPL(get_device);
3765
3766/**
3767 * put_device - decrement reference count.
3768 * @dev: device in question.
3769 */
3770void put_device(struct device *dev)
3771{
3772 /* might_sleep(); */
3773 if (dev)
3774 kobject_put(&dev->kobj);
3775}
3776EXPORT_SYMBOL_GPL(put_device);
3777
3778bool kill_device(struct device *dev)
3779{
3780 /*
3781 * Require the device lock and set the "dead" flag to guarantee that
3782 * the update behavior is consistent with the other bitfields near
3783 * it and that we cannot have an asynchronous probe routine trying
3784 * to run while we are tearing out the bus/class/sysfs from
3785 * underneath the device.
3786 */
3787 device_lock_assert(dev);
3788
3789 if (dev->p->dead)
3790 return false;
3791 dev->p->dead = true;
3792 return true;
3793}
3794EXPORT_SYMBOL_GPL(kill_device);
3795
3796/**
3797 * device_del - delete device from system.
3798 * @dev: device.
3799 *
3800 * This is the first part of the device unregistration
3801 * sequence. This removes the device from the lists we control
3802 * from here, has it removed from the other driver model
3803 * subsystems it was added to in device_add(), and removes it
3804 * from the kobject hierarchy.
3805 *
3806 * NOTE: this should be called manually _iff_ device_add() was
3807 * also called manually.
3808 */
3809void device_del(struct device *dev)
3810{
3811 struct subsys_private *sp;
3812 struct device *parent = dev->parent;
3813 struct kobject *glue_dir = NULL;
3814 struct class_interface *class_intf;
3815 unsigned int noio_flag;
3816
3817 device_lock(dev);
3818 kill_device(dev);
3819 device_unlock(dev);
3820
3821 if (dev->fwnode && dev->fwnode->dev == dev)
3822 dev->fwnode->dev = NULL;
3823
3824 /* Notify clients of device removal. This call must come
3825 * before dpm_sysfs_remove().
3826 */
3827 noio_flag = memalloc_noio_save();
3828 bus_notify(dev, BUS_NOTIFY_DEL_DEVICE);
3829
3830 dpm_sysfs_remove(dev);
3831 if (parent)
3832 klist_del(&dev->p->knode_parent);
3833 if (MAJOR(dev->devt)) {
3834 devtmpfs_delete_node(dev);
3835 device_remove_sys_dev_entry(dev);
3836 device_remove_file(dev, &dev_attr_dev);
3837 }
3838
3839 sp = class_to_subsys(dev->class);
3840 if (sp) {
3841 device_remove_class_symlinks(dev);
3842
3843 mutex_lock(&sp->mutex);
3844 /* notify any interfaces that the device is now gone */
3845 list_for_each_entry(class_intf, &sp->interfaces, node)
3846 if (class_intf->remove_dev)
3847 class_intf->remove_dev(dev);
3848 /* remove the device from the class list */
3849 klist_del(&dev->p->knode_class);
3850 mutex_unlock(&sp->mutex);
3851 subsys_put(sp);
3852 }
3853 device_remove_file(dev, &dev_attr_uevent);
3854 device_remove_attrs(dev);
3855 bus_remove_device(dev);
3856 device_pm_remove(dev);
3857 driver_deferred_probe_del(dev);
3858 device_platform_notify_remove(dev);
3859 device_links_purge(dev);
3860
3861 /*
3862 * If a device does not have a driver attached, we need to clean
3863 * up any managed resources. We do this in device_release(), but
3864 * it's never called (and we leak the device) if a managed
3865 * resource holds a reference to the device. So release all
3866 * managed resources here, like we do in driver_detach(). We
3867 * still need to do so again in device_release() in case someone
3868 * adds a new resource after this point, though.
3869 */
3870 devres_release_all(dev);
3871
3872 bus_notify(dev, BUS_NOTIFY_REMOVED_DEVICE);
3873 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3874 glue_dir = get_glue_dir(dev);
3875 kobject_del(&dev->kobj);
3876 cleanup_glue_dir(dev, glue_dir);
3877 memalloc_noio_restore(noio_flag);
3878 put_device(parent);
3879}
3880EXPORT_SYMBOL_GPL(device_del);
3881
3882/**
3883 * device_unregister - unregister device from system.
3884 * @dev: device going away.
3885 *
3886 * We do this in two parts, like we do device_register(). First,
3887 * we remove it from all the subsystems with device_del(), then
3888 * we decrement the reference count via put_device(). If that
3889 * is the final reference count, the device will be cleaned up
3890 * via device_release() above. Otherwise, the structure will
3891 * stick around until the final reference to the device is dropped.
3892 */
3893void device_unregister(struct device *dev)
3894{
3895 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3896 device_del(dev);
3897 put_device(dev);
3898}
3899EXPORT_SYMBOL_GPL(device_unregister);
3900
3901static struct device *prev_device(struct klist_iter *i)
3902{
3903 struct klist_node *n = klist_prev(i);
3904 struct device *dev = NULL;
3905 struct device_private *p;
3906
3907 if (n) {
3908 p = to_device_private_parent(n);
3909 dev = p->device;
3910 }
3911 return dev;
3912}
3913
3914static struct device *next_device(struct klist_iter *i)
3915{
3916 struct klist_node *n = klist_next(i);
3917 struct device *dev = NULL;
3918 struct device_private *p;
3919
3920 if (n) {
3921 p = to_device_private_parent(n);
3922 dev = p->device;
3923 }
3924 return dev;
3925}
3926
3927/**
3928 * device_get_devnode - path of device node file
3929 * @dev: device
3930 * @mode: returned file access mode
3931 * @uid: returned file owner
3932 * @gid: returned file group
3933 * @tmp: possibly allocated string
3934 *
3935 * Return the relative path of a possible device node.
3936 * Non-default names may need to allocate a memory to compose
3937 * a name. This memory is returned in tmp and needs to be
3938 * freed by the caller.
3939 */
3940const char *device_get_devnode(const struct device *dev,
3941 umode_t *mode, kuid_t *uid, kgid_t *gid,
3942 const char **tmp)
3943{
3944 char *s;
3945
3946 *tmp = NULL;
3947
3948 /* the device type may provide a specific name */
3949 if (dev->type && dev->type->devnode)
3950 *tmp = dev->type->devnode(dev, mode, uid, gid);
3951 if (*tmp)
3952 return *tmp;
3953
3954 /* the class may provide a specific name */
3955 if (dev->class && dev->class->devnode)
3956 *tmp = dev->class->devnode(dev, mode);
3957 if (*tmp)
3958 return *tmp;
3959
3960 /* return name without allocation, tmp == NULL */
3961 if (strchr(dev_name(dev), '!') == NULL)
3962 return dev_name(dev);
3963
3964 /* replace '!' in the name with '/' */
3965 s = kstrdup_and_replace(dev_name(dev), '!', '/', GFP_KERNEL);
3966 if (!s)
3967 return NULL;
3968 return *tmp = s;
3969}
3970
3971/**
3972 * device_for_each_child - device child iterator.
3973 * @parent: parent struct device.
3974 * @fn: function to be called for each device.
3975 * @data: data for the callback.
3976 *
3977 * Iterate over @parent's child devices, and call @fn for each,
3978 * passing it @data.
3979 *
3980 * We check the return of @fn each time. If it returns anything
3981 * other than 0, we break out and return that value.
3982 */
3983int device_for_each_child(struct device *parent, void *data,
3984 int (*fn)(struct device *dev, void *data))
3985{
3986 struct klist_iter i;
3987 struct device *child;
3988 int error = 0;
3989
3990 if (!parent || !parent->p)
3991 return 0;
3992
3993 klist_iter_init(&parent->p->klist_children, &i);
3994 while (!error && (child = next_device(&i)))
3995 error = fn(child, data);
3996 klist_iter_exit(&i);
3997 return error;
3998}
3999EXPORT_SYMBOL_GPL(device_for_each_child);
4000
4001/**
4002 * device_for_each_child_reverse - device child iterator in reversed order.
4003 * @parent: parent struct device.
4004 * @fn: function to be called for each device.
4005 * @data: data for the callback.
4006 *
4007 * Iterate over @parent's child devices, and call @fn for each,
4008 * passing it @data.
4009 *
4010 * We check the return of @fn each time. If it returns anything
4011 * other than 0, we break out and return that value.
4012 */
4013int device_for_each_child_reverse(struct device *parent, void *data,
4014 int (*fn)(struct device *dev, void *data))
4015{
4016 struct klist_iter i;
4017 struct device *child;
4018 int error = 0;
4019
4020 if (!parent || !parent->p)
4021 return 0;
4022
4023 klist_iter_init(&parent->p->klist_children, &i);
4024 while ((child = prev_device(&i)) && !error)
4025 error = fn(child, data);
4026 klist_iter_exit(&i);
4027 return error;
4028}
4029EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
4030
4031/**
4032 * device_for_each_child_reverse_from - device child iterator in reversed order.
4033 * @parent: parent struct device.
4034 * @from: optional starting point in child list
4035 * @fn: function to be called for each device.
4036 * @data: data for the callback.
4037 *
4038 * Iterate over @parent's child devices, starting at @from, and call @fn
4039 * for each, passing it @data. This helper is identical to
4040 * device_for_each_child_reverse() when @from is NULL.
4041 *
4042 * @fn is checked each iteration. If it returns anything other than 0,
4043 * iteration stop and that value is returned to the caller of
4044 * device_for_each_child_reverse_from();
4045 */
4046int device_for_each_child_reverse_from(struct device *parent,
4047 struct device *from, const void *data,
4048 int (*fn)(struct device *, const void *))
4049{
4050 struct klist_iter i;
4051 struct device *child;
4052 int error = 0;
4053
4054 if (!parent->p)
4055 return 0;
4056
4057 klist_iter_init_node(&parent->p->klist_children, &i,
4058 (from ? &from->p->knode_parent : NULL));
4059 while ((child = prev_device(&i)) && !error)
4060 error = fn(child, data);
4061 klist_iter_exit(&i);
4062 return error;
4063}
4064EXPORT_SYMBOL_GPL(device_for_each_child_reverse_from);
4065
4066/**
4067 * device_find_child - device iterator for locating a particular device.
4068 * @parent: parent struct device
4069 * @match: Callback function to check device
4070 * @data: Data to pass to match function
4071 *
4072 * This is similar to the device_for_each_child() function above, but it
4073 * returns a reference to a device that is 'found' for later use, as
4074 * determined by the @match callback.
4075 *
4076 * The callback should return 0 if the device doesn't match and non-zero
4077 * if it does. If the callback returns non-zero and a reference to the
4078 * current device can be obtained, this function will return to the caller
4079 * and not iterate over any more devices.
4080 *
4081 * NOTE: you will need to drop the reference with put_device() after use.
4082 */
4083struct device *device_find_child(struct device *parent, void *data,
4084 int (*match)(struct device *dev, void *data))
4085{
4086 struct klist_iter i;
4087 struct device *child;
4088
4089 if (!parent || !parent->p)
4090 return NULL;
4091
4092 klist_iter_init(&parent->p->klist_children, &i);
4093 while ((child = next_device(&i)))
4094 if (match(child, data) && get_device(child))
4095 break;
4096 klist_iter_exit(&i);
4097 return child;
4098}
4099EXPORT_SYMBOL_GPL(device_find_child);
4100
4101/**
4102 * device_find_child_by_name - device iterator for locating a child device.
4103 * @parent: parent struct device
4104 * @name: name of the child device
4105 *
4106 * This is similar to the device_find_child() function above, but it
4107 * returns a reference to a device that has the name @name.
4108 *
4109 * NOTE: you will need to drop the reference with put_device() after use.
4110 */
4111struct device *device_find_child_by_name(struct device *parent,
4112 const char *name)
4113{
4114 struct klist_iter i;
4115 struct device *child;
4116
4117 if (!parent)
4118 return NULL;
4119
4120 klist_iter_init(&parent->p->klist_children, &i);
4121 while ((child = next_device(&i)))
4122 if (sysfs_streq(dev_name(child), name) && get_device(child))
4123 break;
4124 klist_iter_exit(&i);
4125 return child;
4126}
4127EXPORT_SYMBOL_GPL(device_find_child_by_name);
4128
4129static int match_any(struct device *dev, void *unused)
4130{
4131 return 1;
4132}
4133
4134/**
4135 * device_find_any_child - device iterator for locating a child device, if any.
4136 * @parent: parent struct device
4137 *
4138 * This is similar to the device_find_child() function above, but it
4139 * returns a reference to a child device, if any.
4140 *
4141 * NOTE: you will need to drop the reference with put_device() after use.
4142 */
4143struct device *device_find_any_child(struct device *parent)
4144{
4145 return device_find_child(parent, NULL, match_any);
4146}
4147EXPORT_SYMBOL_GPL(device_find_any_child);
4148
4149int __init devices_init(void)
4150{
4151 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
4152 if (!devices_kset)
4153 return -ENOMEM;
4154 dev_kobj = kobject_create_and_add("dev", NULL);
4155 if (!dev_kobj)
4156 goto dev_kobj_err;
4157 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
4158 if (!sysfs_dev_block_kobj)
4159 goto block_kobj_err;
4160 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
4161 if (!sysfs_dev_char_kobj)
4162 goto char_kobj_err;
4163 device_link_wq = alloc_workqueue("device_link_wq", 0, 0);
4164 if (!device_link_wq)
4165 goto wq_err;
4166
4167 return 0;
4168
4169 wq_err:
4170 kobject_put(sysfs_dev_char_kobj);
4171 char_kobj_err:
4172 kobject_put(sysfs_dev_block_kobj);
4173 block_kobj_err:
4174 kobject_put(dev_kobj);
4175 dev_kobj_err:
4176 kset_unregister(devices_kset);
4177 return -ENOMEM;
4178}
4179
4180static int device_check_offline(struct device *dev, void *not_used)
4181{
4182 int ret;
4183
4184 ret = device_for_each_child(dev, NULL, device_check_offline);
4185 if (ret)
4186 return ret;
4187
4188 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
4189}
4190
4191/**
4192 * device_offline - Prepare the device for hot-removal.
4193 * @dev: Device to be put offline.
4194 *
4195 * Execute the device bus type's .offline() callback, if present, to prepare
4196 * the device for a subsequent hot-removal. If that succeeds, the device must
4197 * not be used until either it is removed or its bus type's .online() callback
4198 * is executed.
4199 *
4200 * Call under device_hotplug_lock.
4201 */
4202int device_offline(struct device *dev)
4203{
4204 int ret;
4205
4206 if (dev->offline_disabled)
4207 return -EPERM;
4208
4209 ret = device_for_each_child(dev, NULL, device_check_offline);
4210 if (ret)
4211 return ret;
4212
4213 device_lock(dev);
4214 if (device_supports_offline(dev)) {
4215 if (dev->offline) {
4216 ret = 1;
4217 } else {
4218 ret = dev->bus->offline(dev);
4219 if (!ret) {
4220 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
4221 dev->offline = true;
4222 }
4223 }
4224 }
4225 device_unlock(dev);
4226
4227 return ret;
4228}
4229
4230/**
4231 * device_online - Put the device back online after successful device_offline().
4232 * @dev: Device to be put back online.
4233 *
4234 * If device_offline() has been successfully executed for @dev, but the device
4235 * has not been removed subsequently, execute its bus type's .online() callback
4236 * to indicate that the device can be used again.
4237 *
4238 * Call under device_hotplug_lock.
4239 */
4240int device_online(struct device *dev)
4241{
4242 int ret = 0;
4243
4244 device_lock(dev);
4245 if (device_supports_offline(dev)) {
4246 if (dev->offline) {
4247 ret = dev->bus->online(dev);
4248 if (!ret) {
4249 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
4250 dev->offline = false;
4251 }
4252 } else {
4253 ret = 1;
4254 }
4255 }
4256 device_unlock(dev);
4257
4258 return ret;
4259}
4260
4261struct root_device {
4262 struct device dev;
4263 struct module *owner;
4264};
4265
4266static inline struct root_device *to_root_device(struct device *d)
4267{
4268 return container_of(d, struct root_device, dev);
4269}
4270
4271static void root_device_release(struct device *dev)
4272{
4273 kfree(to_root_device(dev));
4274}
4275
4276/**
4277 * __root_device_register - allocate and register a root device
4278 * @name: root device name
4279 * @owner: owner module of the root device, usually THIS_MODULE
4280 *
4281 * This function allocates a root device and registers it
4282 * using device_register(). In order to free the returned
4283 * device, use root_device_unregister().
4284 *
4285 * Root devices are dummy devices which allow other devices
4286 * to be grouped under /sys/devices. Use this function to
4287 * allocate a root device and then use it as the parent of
4288 * any device which should appear under /sys/devices/{name}
4289 *
4290 * The /sys/devices/{name} directory will also contain a
4291 * 'module' symlink which points to the @owner directory
4292 * in sysfs.
4293 *
4294 * Returns &struct device pointer on success, or ERR_PTR() on error.
4295 *
4296 * Note: You probably want to use root_device_register().
4297 */
4298struct device *__root_device_register(const char *name, struct module *owner)
4299{
4300 struct root_device *root;
4301 int err = -ENOMEM;
4302
4303 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
4304 if (!root)
4305 return ERR_PTR(err);
4306
4307 err = dev_set_name(&root->dev, "%s", name);
4308 if (err) {
4309 kfree(root);
4310 return ERR_PTR(err);
4311 }
4312
4313 root->dev.release = root_device_release;
4314
4315 err = device_register(&root->dev);
4316 if (err) {
4317 put_device(&root->dev);
4318 return ERR_PTR(err);
4319 }
4320
4321#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
4322 if (owner) {
4323 struct module_kobject *mk = &owner->mkobj;
4324
4325 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
4326 if (err) {
4327 device_unregister(&root->dev);
4328 return ERR_PTR(err);
4329 }
4330 root->owner = owner;
4331 }
4332#endif
4333
4334 return &root->dev;
4335}
4336EXPORT_SYMBOL_GPL(__root_device_register);
4337
4338/**
4339 * root_device_unregister - unregister and free a root device
4340 * @dev: device going away
4341 *
4342 * This function unregisters and cleans up a device that was created by
4343 * root_device_register().
4344 */
4345void root_device_unregister(struct device *dev)
4346{
4347 struct root_device *root = to_root_device(dev);
4348
4349 if (root->owner)
4350 sysfs_remove_link(&root->dev.kobj, "module");
4351
4352 device_unregister(dev);
4353}
4354EXPORT_SYMBOL_GPL(root_device_unregister);
4355
4356
4357static void device_create_release(struct device *dev)
4358{
4359 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
4360 kfree(dev);
4361}
4362
4363static __printf(6, 0) struct device *
4364device_create_groups_vargs(const struct class *class, struct device *parent,
4365 dev_t devt, void *drvdata,
4366 const struct attribute_group **groups,
4367 const char *fmt, va_list args)
4368{
4369 struct device *dev = NULL;
4370 int retval = -ENODEV;
4371
4372 if (IS_ERR_OR_NULL(class))
4373 goto error;
4374
4375 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
4376 if (!dev) {
4377 retval = -ENOMEM;
4378 goto error;
4379 }
4380
4381 device_initialize(dev);
4382 dev->devt = devt;
4383 dev->class = class;
4384 dev->parent = parent;
4385 dev->groups = groups;
4386 dev->release = device_create_release;
4387 dev_set_drvdata(dev, drvdata);
4388
4389 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
4390 if (retval)
4391 goto error;
4392
4393 retval = device_add(dev);
4394 if (retval)
4395 goto error;
4396
4397 return dev;
4398
4399error:
4400 put_device(dev);
4401 return ERR_PTR(retval);
4402}
4403
4404/**
4405 * device_create - creates a device and registers it with sysfs
4406 * @class: pointer to the struct class that this device should be registered to
4407 * @parent: pointer to the parent struct device of this new device, if any
4408 * @devt: the dev_t for the char device to be added
4409 * @drvdata: the data to be added to the device for callbacks
4410 * @fmt: string for the device's name
4411 *
4412 * This function can be used by char device classes. A struct device
4413 * will be created in sysfs, registered to the specified class.
4414 *
4415 * A "dev" file will be created, showing the dev_t for the device, if
4416 * the dev_t is not 0,0.
4417 * If a pointer to a parent struct device is passed in, the newly created
4418 * struct device will be a child of that device in sysfs.
4419 * The pointer to the struct device will be returned from the call.
4420 * Any further sysfs files that might be required can be created using this
4421 * pointer.
4422 *
4423 * Returns &struct device pointer on success, or ERR_PTR() on error.
4424 */
4425struct device *device_create(const struct class *class, struct device *parent,
4426 dev_t devt, void *drvdata, const char *fmt, ...)
4427{
4428 va_list vargs;
4429 struct device *dev;
4430
4431 va_start(vargs, fmt);
4432 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
4433 fmt, vargs);
4434 va_end(vargs);
4435 return dev;
4436}
4437EXPORT_SYMBOL_GPL(device_create);
4438
4439/**
4440 * device_create_with_groups - creates a device and registers it with sysfs
4441 * @class: pointer to the struct class that this device should be registered to
4442 * @parent: pointer to the parent struct device of this new device, if any
4443 * @devt: the dev_t for the char device to be added
4444 * @drvdata: the data to be added to the device for callbacks
4445 * @groups: NULL-terminated list of attribute groups to be created
4446 * @fmt: string for the device's name
4447 *
4448 * This function can be used by char device classes. A struct device
4449 * will be created in sysfs, registered to the specified class.
4450 * Additional attributes specified in the groups parameter will also
4451 * be created automatically.
4452 *
4453 * A "dev" file will be created, showing the dev_t for the device, if
4454 * the dev_t is not 0,0.
4455 * If a pointer to a parent struct device is passed in, the newly created
4456 * struct device will be a child of that device in sysfs.
4457 * The pointer to the struct device will be returned from the call.
4458 * Any further sysfs files that might be required can be created using this
4459 * pointer.
4460 *
4461 * Returns &struct device pointer on success, or ERR_PTR() on error.
4462 */
4463struct device *device_create_with_groups(const struct class *class,
4464 struct device *parent, dev_t devt,
4465 void *drvdata,
4466 const struct attribute_group **groups,
4467 const char *fmt, ...)
4468{
4469 va_list vargs;
4470 struct device *dev;
4471
4472 va_start(vargs, fmt);
4473 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
4474 fmt, vargs);
4475 va_end(vargs);
4476 return dev;
4477}
4478EXPORT_SYMBOL_GPL(device_create_with_groups);
4479
4480/**
4481 * device_destroy - removes a device that was created with device_create()
4482 * @class: pointer to the struct class that this device was registered with
4483 * @devt: the dev_t of the device that was previously registered
4484 *
4485 * This call unregisters and cleans up a device that was created with a
4486 * call to device_create().
4487 */
4488void device_destroy(const struct class *class, dev_t devt)
4489{
4490 struct device *dev;
4491
4492 dev = class_find_device_by_devt(class, devt);
4493 if (dev) {
4494 put_device(dev);
4495 device_unregister(dev);
4496 }
4497}
4498EXPORT_SYMBOL_GPL(device_destroy);
4499
4500/**
4501 * device_rename - renames a device
4502 * @dev: the pointer to the struct device to be renamed
4503 * @new_name: the new name of the device
4504 *
4505 * It is the responsibility of the caller to provide mutual
4506 * exclusion between two different calls of device_rename
4507 * on the same device to ensure that new_name is valid and
4508 * won't conflict with other devices.
4509 *
4510 * Note: given that some subsystems (networking and infiniband) use this
4511 * function, with no immediate plans for this to change, we cannot assume or
4512 * require that this function not be called at all.
4513 *
4514 * However, if you're writing new code, do not call this function. The following
4515 * text from Kay Sievers offers some insight:
4516 *
4517 * Renaming devices is racy at many levels, symlinks and other stuff are not
4518 * replaced atomically, and you get a "move" uevent, but it's not easy to
4519 * connect the event to the old and new device. Device nodes are not renamed at
4520 * all, there isn't even support for that in the kernel now.
4521 *
4522 * In the meantime, during renaming, your target name might be taken by another
4523 * driver, creating conflicts. Or the old name is taken directly after you
4524 * renamed it -- then you get events for the same DEVPATH, before you even see
4525 * the "move" event. It's just a mess, and nothing new should ever rely on
4526 * kernel device renaming. Besides that, it's not even implemented now for
4527 * other things than (driver-core wise very simple) network devices.
4528 *
4529 * Make up a "real" name in the driver before you register anything, or add
4530 * some other attributes for userspace to find the device, or use udev to add
4531 * symlinks -- but never rename kernel devices later, it's a complete mess. We
4532 * don't even want to get into that and try to implement the missing pieces in
4533 * the core. We really have other pieces to fix in the driver core mess. :)
4534 */
4535int device_rename(struct device *dev, const char *new_name)
4536{
4537 struct subsys_private *sp = NULL;
4538 struct kobject *kobj = &dev->kobj;
4539 char *old_device_name = NULL;
4540 int error;
4541 bool is_link_renamed = false;
4542
4543 dev = get_device(dev);
4544 if (!dev)
4545 return -EINVAL;
4546
4547 dev_dbg(dev, "renaming to %s\n", new_name);
4548
4549 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
4550 if (!old_device_name) {
4551 error = -ENOMEM;
4552 goto out;
4553 }
4554
4555 if (dev->class) {
4556 sp = class_to_subsys(dev->class);
4557
4558 if (!sp) {
4559 error = -EINVAL;
4560 goto out;
4561 }
4562
4563 error = sysfs_rename_link_ns(&sp->subsys.kobj, kobj, old_device_name,
4564 new_name, kobject_namespace(kobj));
4565 if (error)
4566 goto out;
4567
4568 is_link_renamed = true;
4569 }
4570
4571 error = kobject_rename(kobj, new_name);
4572out:
4573 if (error && is_link_renamed)
4574 sysfs_rename_link_ns(&sp->subsys.kobj, kobj, new_name,
4575 old_device_name, kobject_namespace(kobj));
4576 subsys_put(sp);
4577
4578 put_device(dev);
4579
4580 kfree(old_device_name);
4581
4582 return error;
4583}
4584EXPORT_SYMBOL_GPL(device_rename);
4585
4586static int device_move_class_links(struct device *dev,
4587 struct device *old_parent,
4588 struct device *new_parent)
4589{
4590 int error = 0;
4591
4592 if (old_parent)
4593 sysfs_remove_link(&dev->kobj, "device");
4594 if (new_parent)
4595 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
4596 "device");
4597 return error;
4598}
4599
4600/**
4601 * device_move - moves a device to a new parent
4602 * @dev: the pointer to the struct device to be moved
4603 * @new_parent: the new parent of the device (can be NULL)
4604 * @dpm_order: how to reorder the dpm_list
4605 */
4606int device_move(struct device *dev, struct device *new_parent,
4607 enum dpm_order dpm_order)
4608{
4609 int error;
4610 struct device *old_parent;
4611 struct kobject *new_parent_kobj;
4612
4613 dev = get_device(dev);
4614 if (!dev)
4615 return -EINVAL;
4616
4617 device_pm_lock();
4618 new_parent = get_device(new_parent);
4619 new_parent_kobj = get_device_parent(dev, new_parent);
4620 if (IS_ERR(new_parent_kobj)) {
4621 error = PTR_ERR(new_parent_kobj);
4622 put_device(new_parent);
4623 goto out;
4624 }
4625
4626 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
4627 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
4628 error = kobject_move(&dev->kobj, new_parent_kobj);
4629 if (error) {
4630 cleanup_glue_dir(dev, new_parent_kobj);
4631 put_device(new_parent);
4632 goto out;
4633 }
4634 old_parent = dev->parent;
4635 dev->parent = new_parent;
4636 if (old_parent)
4637 klist_remove(&dev->p->knode_parent);
4638 if (new_parent) {
4639 klist_add_tail(&dev->p->knode_parent,
4640 &new_parent->p->klist_children);
4641 set_dev_node(dev, dev_to_node(new_parent));
4642 }
4643
4644 if (dev->class) {
4645 error = device_move_class_links(dev, old_parent, new_parent);
4646 if (error) {
4647 /* We ignore errors on cleanup since we're hosed anyway... */
4648 device_move_class_links(dev, new_parent, old_parent);
4649 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
4650 if (new_parent)
4651 klist_remove(&dev->p->knode_parent);
4652 dev->parent = old_parent;
4653 if (old_parent) {
4654 klist_add_tail(&dev->p->knode_parent,
4655 &old_parent->p->klist_children);
4656 set_dev_node(dev, dev_to_node(old_parent));
4657 }
4658 }
4659 cleanup_glue_dir(dev, new_parent_kobj);
4660 put_device(new_parent);
4661 goto out;
4662 }
4663 }
4664 switch (dpm_order) {
4665 case DPM_ORDER_NONE:
4666 break;
4667 case DPM_ORDER_DEV_AFTER_PARENT:
4668 device_pm_move_after(dev, new_parent);
4669 devices_kset_move_after(dev, new_parent);
4670 break;
4671 case DPM_ORDER_PARENT_BEFORE_DEV:
4672 device_pm_move_before(new_parent, dev);
4673 devices_kset_move_before(new_parent, dev);
4674 break;
4675 case DPM_ORDER_DEV_LAST:
4676 device_pm_move_last(dev);
4677 devices_kset_move_last(dev);
4678 break;
4679 }
4680
4681 put_device(old_parent);
4682out:
4683 device_pm_unlock();
4684 put_device(dev);
4685 return error;
4686}
4687EXPORT_SYMBOL_GPL(device_move);
4688
4689static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
4690 kgid_t kgid)
4691{
4692 struct kobject *kobj = &dev->kobj;
4693 const struct class *class = dev->class;
4694 const struct device_type *type = dev->type;
4695 int error;
4696
4697 if (class) {
4698 /*
4699 * Change the device groups of the device class for @dev to
4700 * @kuid/@kgid.
4701 */
4702 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
4703 kgid);
4704 if (error)
4705 return error;
4706 }
4707
4708 if (type) {
4709 /*
4710 * Change the device groups of the device type for @dev to
4711 * @kuid/@kgid.
4712 */
4713 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
4714 kgid);
4715 if (error)
4716 return error;
4717 }
4718
4719 /* Change the device groups of @dev to @kuid/@kgid. */
4720 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
4721 if (error)
4722 return error;
4723
4724 if (device_supports_offline(dev) && !dev->offline_disabled) {
4725 /* Change online device attributes of @dev to @kuid/@kgid. */
4726 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
4727 kuid, kgid);
4728 if (error)
4729 return error;
4730 }
4731
4732 return 0;
4733}
4734
4735/**
4736 * device_change_owner - change the owner of an existing device.
4737 * @dev: device.
4738 * @kuid: new owner's kuid
4739 * @kgid: new owner's kgid
4740 *
4741 * This changes the owner of @dev and its corresponding sysfs entries to
4742 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
4743 * core.
4744 *
4745 * Returns 0 on success or error code on failure.
4746 */
4747int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
4748{
4749 int error;
4750 struct kobject *kobj = &dev->kobj;
4751 struct subsys_private *sp;
4752
4753 dev = get_device(dev);
4754 if (!dev)
4755 return -EINVAL;
4756
4757 /*
4758 * Change the kobject and the default attributes and groups of the
4759 * ktype associated with it to @kuid/@kgid.
4760 */
4761 error = sysfs_change_owner(kobj, kuid, kgid);
4762 if (error)
4763 goto out;
4764
4765 /*
4766 * Change the uevent file for @dev to the new owner. The uevent file
4767 * was created in a separate step when @dev got added and we mirror
4768 * that step here.
4769 */
4770 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
4771 kgid);
4772 if (error)
4773 goto out;
4774
4775 /*
4776 * Change the device groups, the device groups associated with the
4777 * device class, and the groups associated with the device type of @dev
4778 * to @kuid/@kgid.
4779 */
4780 error = device_attrs_change_owner(dev, kuid, kgid);
4781 if (error)
4782 goto out;
4783
4784 error = dpm_sysfs_change_owner(dev, kuid, kgid);
4785 if (error)
4786 goto out;
4787
4788 /*
4789 * Change the owner of the symlink located in the class directory of
4790 * the device class associated with @dev which points to the actual
4791 * directory entry for @dev to @kuid/@kgid. This ensures that the
4792 * symlink shows the same permissions as its target.
4793 */
4794 sp = class_to_subsys(dev->class);
4795 if (!sp) {
4796 error = -EINVAL;
4797 goto out;
4798 }
4799 error = sysfs_link_change_owner(&sp->subsys.kobj, &dev->kobj, dev_name(dev), kuid, kgid);
4800 subsys_put(sp);
4801
4802out:
4803 put_device(dev);
4804 return error;
4805}
4806EXPORT_SYMBOL_GPL(device_change_owner);
4807
4808/**
4809 * device_shutdown - call ->shutdown() on each device to shutdown.
4810 */
4811void device_shutdown(void)
4812{
4813 struct device *dev, *parent;
4814
4815 wait_for_device_probe();
4816 device_block_probing();
4817
4818 cpufreq_suspend();
4819
4820 spin_lock(&devices_kset->list_lock);
4821 /*
4822 * Walk the devices list backward, shutting down each in turn.
4823 * Beware that device unplug events may also start pulling
4824 * devices offline, even as the system is shutting down.
4825 */
4826 while (!list_empty(&devices_kset->list)) {
4827 dev = list_entry(devices_kset->list.prev, struct device,
4828 kobj.entry);
4829
4830 /*
4831 * hold reference count of device's parent to
4832 * prevent it from being freed because parent's
4833 * lock is to be held
4834 */
4835 parent = get_device(dev->parent);
4836 get_device(dev);
4837 /*
4838 * Make sure the device is off the kset list, in the
4839 * event that dev->*->shutdown() doesn't remove it.
4840 */
4841 list_del_init(&dev->kobj.entry);
4842 spin_unlock(&devices_kset->list_lock);
4843
4844 /* hold lock to avoid race with probe/release */
4845 if (parent)
4846 device_lock(parent);
4847 device_lock(dev);
4848
4849 /* Don't allow any more runtime suspends */
4850 pm_runtime_get_noresume(dev);
4851 pm_runtime_barrier(dev);
4852
4853 if (dev->class && dev->class->shutdown_pre) {
4854 if (initcall_debug)
4855 dev_info(dev, "shutdown_pre\n");
4856 dev->class->shutdown_pre(dev);
4857 }
4858 if (dev->bus && dev->bus->shutdown) {
4859 if (initcall_debug)
4860 dev_info(dev, "shutdown\n");
4861 dev->bus->shutdown(dev);
4862 } else if (dev->driver && dev->driver->shutdown) {
4863 if (initcall_debug)
4864 dev_info(dev, "shutdown\n");
4865 dev->driver->shutdown(dev);
4866 }
4867
4868 device_unlock(dev);
4869 if (parent)
4870 device_unlock(parent);
4871
4872 put_device(dev);
4873 put_device(parent);
4874
4875 spin_lock(&devices_kset->list_lock);
4876 }
4877 spin_unlock(&devices_kset->list_lock);
4878}
4879
4880/*
4881 * Device logging functions
4882 */
4883
4884#ifdef CONFIG_PRINTK
4885static void
4886set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4887{
4888 const char *subsys;
4889
4890 memset(dev_info, 0, sizeof(*dev_info));
4891
4892 if (dev->class)
4893 subsys = dev->class->name;
4894 else if (dev->bus)
4895 subsys = dev->bus->name;
4896 else
4897 return;
4898
4899 strscpy(dev_info->subsystem, subsys);
4900
4901 /*
4902 * Add device identifier DEVICE=:
4903 * b12:8 block dev_t
4904 * c127:3 char dev_t
4905 * n8 netdev ifindex
4906 * +sound:card0 subsystem:devname
4907 */
4908 if (MAJOR(dev->devt)) {
4909 char c;
4910
4911 if (strcmp(subsys, "block") == 0)
4912 c = 'b';
4913 else
4914 c = 'c';
4915
4916 snprintf(dev_info->device, sizeof(dev_info->device),
4917 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4918 } else if (strcmp(subsys, "net") == 0) {
4919 struct net_device *net = to_net_dev(dev);
4920
4921 snprintf(dev_info->device, sizeof(dev_info->device),
4922 "n%u", net->ifindex);
4923 } else {
4924 snprintf(dev_info->device, sizeof(dev_info->device),
4925 "+%s:%s", subsys, dev_name(dev));
4926 }
4927}
4928
4929int dev_vprintk_emit(int level, const struct device *dev,
4930 const char *fmt, va_list args)
4931{
4932 struct dev_printk_info dev_info;
4933
4934 set_dev_info(dev, &dev_info);
4935
4936 return vprintk_emit(0, level, &dev_info, fmt, args);
4937}
4938EXPORT_SYMBOL(dev_vprintk_emit);
4939
4940int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4941{
4942 va_list args;
4943 int r;
4944
4945 va_start(args, fmt);
4946
4947 r = dev_vprintk_emit(level, dev, fmt, args);
4948
4949 va_end(args);
4950
4951 return r;
4952}
4953EXPORT_SYMBOL(dev_printk_emit);
4954
4955static void __dev_printk(const char *level, const struct device *dev,
4956 struct va_format *vaf)
4957{
4958 if (dev)
4959 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4960 dev_driver_string(dev), dev_name(dev), vaf);
4961 else
4962 printk("%s(NULL device *): %pV", level, vaf);
4963}
4964
4965void _dev_printk(const char *level, const struct device *dev,
4966 const char *fmt, ...)
4967{
4968 struct va_format vaf;
4969 va_list args;
4970
4971 va_start(args, fmt);
4972
4973 vaf.fmt = fmt;
4974 vaf.va = &args;
4975
4976 __dev_printk(level, dev, &vaf);
4977
4978 va_end(args);
4979}
4980EXPORT_SYMBOL(_dev_printk);
4981
4982#define define_dev_printk_level(func, kern_level) \
4983void func(const struct device *dev, const char *fmt, ...) \
4984{ \
4985 struct va_format vaf; \
4986 va_list args; \
4987 \
4988 va_start(args, fmt); \
4989 \
4990 vaf.fmt = fmt; \
4991 vaf.va = &args; \
4992 \
4993 __dev_printk(kern_level, dev, &vaf); \
4994 \
4995 va_end(args); \
4996} \
4997EXPORT_SYMBOL(func);
4998
4999define_dev_printk_level(_dev_emerg, KERN_EMERG);
5000define_dev_printk_level(_dev_alert, KERN_ALERT);
5001define_dev_printk_level(_dev_crit, KERN_CRIT);
5002define_dev_printk_level(_dev_err, KERN_ERR);
5003define_dev_printk_level(_dev_warn, KERN_WARNING);
5004define_dev_printk_level(_dev_notice, KERN_NOTICE);
5005define_dev_printk_level(_dev_info, KERN_INFO);
5006
5007#endif
5008
5009static void __dev_probe_failed(const struct device *dev, int err, bool fatal,
5010 const char *fmt, va_list vargsp)
5011{
5012 struct va_format vaf;
5013 va_list vargs;
5014
5015 /*
5016 * On x86_64 and possibly on other architectures, va_list is actually a
5017 * size-1 array containing a structure. As a result, function parameter
5018 * vargsp decays from T[1] to T*, and &vargsp has type T** rather than
5019 * T(*)[1], which is expected by its assignment to vaf.va below.
5020 *
5021 * One standard way to solve this mess is by creating a copy in a local
5022 * variable of type va_list and then using a pointer to that local copy
5023 * instead, which is the approach employed here.
5024 */
5025 va_copy(vargs, vargsp);
5026
5027 vaf.fmt = fmt;
5028 vaf.va = &vargs;
5029
5030 switch (err) {
5031 case -EPROBE_DEFER:
5032 device_set_deferred_probe_reason(dev, &vaf);
5033 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
5034 break;
5035
5036 case -ENOMEM:
5037 /* Don't print anything on -ENOMEM, there's already enough output */
5038 break;
5039
5040 default:
5041 /* Log fatal final failures as errors, otherwise produce warnings */
5042 if (fatal)
5043 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
5044 else
5045 dev_warn(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
5046 break;
5047 }
5048
5049 va_end(vargs);
5050}
5051
5052/**
5053 * dev_err_probe - probe error check and log helper
5054 * @dev: the pointer to the struct device
5055 * @err: error value to test
5056 * @fmt: printf-style format string
5057 * @...: arguments as specified in the format string
5058 *
5059 * This helper implements common pattern present in probe functions for error
5060 * checking: print debug or error message depending if the error value is
5061 * -EPROBE_DEFER and propagate error upwards.
5062 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
5063 * checked later by reading devices_deferred debugfs attribute.
5064 * It replaces the following code sequence::
5065 *
5066 * if (err != -EPROBE_DEFER)
5067 * dev_err(dev, ...);
5068 * else
5069 * dev_dbg(dev, ...);
5070 * return err;
5071 *
5072 * with::
5073 *
5074 * return dev_err_probe(dev, err, ...);
5075 *
5076 * Using this helper in your probe function is totally fine even if @err
5077 * is known to never be -EPROBE_DEFER.
5078 * The benefit compared to a normal dev_err() is the standardized format
5079 * of the error code, which is emitted symbolically (i.e. you get "EAGAIN"
5080 * instead of "-35"), and having the error code returned allows more
5081 * compact error paths.
5082 *
5083 * Returns @err.
5084 */
5085int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
5086{
5087 va_list vargs;
5088
5089 va_start(vargs, fmt);
5090
5091 /* Use dev_err() for logging when err doesn't equal -EPROBE_DEFER */
5092 __dev_probe_failed(dev, err, true, fmt, vargs);
5093
5094 va_end(vargs);
5095
5096 return err;
5097}
5098EXPORT_SYMBOL_GPL(dev_err_probe);
5099
5100/**
5101 * dev_warn_probe - probe error check and log helper
5102 * @dev: the pointer to the struct device
5103 * @err: error value to test
5104 * @fmt: printf-style format string
5105 * @...: arguments as specified in the format string
5106 *
5107 * This helper implements common pattern present in probe functions for error
5108 * checking: print debug or warning message depending if the error value is
5109 * -EPROBE_DEFER and propagate error upwards.
5110 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
5111 * checked later by reading devices_deferred debugfs attribute.
5112 * It replaces the following code sequence::
5113 *
5114 * if (err != -EPROBE_DEFER)
5115 * dev_warn(dev, ...);
5116 * else
5117 * dev_dbg(dev, ...);
5118 * return err;
5119 *
5120 * with::
5121 *
5122 * return dev_warn_probe(dev, err, ...);
5123 *
5124 * Using this helper in your probe function is totally fine even if @err
5125 * is known to never be -EPROBE_DEFER.
5126 * The benefit compared to a normal dev_warn() is the standardized format
5127 * of the error code, which is emitted symbolically (i.e. you get "EAGAIN"
5128 * instead of "-35"), and having the error code returned allows more
5129 * compact error paths.
5130 *
5131 * Returns @err.
5132 */
5133int dev_warn_probe(const struct device *dev, int err, const char *fmt, ...)
5134{
5135 va_list vargs;
5136
5137 va_start(vargs, fmt);
5138
5139 /* Use dev_warn() for logging when err doesn't equal -EPROBE_DEFER */
5140 __dev_probe_failed(dev, err, false, fmt, vargs);
5141
5142 va_end(vargs);
5143
5144 return err;
5145}
5146EXPORT_SYMBOL_GPL(dev_warn_probe);
5147
5148static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
5149{
5150 return fwnode && !IS_ERR(fwnode->secondary);
5151}
5152
5153/**
5154 * set_primary_fwnode - Change the primary firmware node of a given device.
5155 * @dev: Device to handle.
5156 * @fwnode: New primary firmware node of the device.
5157 *
5158 * Set the device's firmware node pointer to @fwnode, but if a secondary
5159 * firmware node of the device is present, preserve it.
5160 *
5161 * Valid fwnode cases are:
5162 * - primary --> secondary --> -ENODEV
5163 * - primary --> NULL
5164 * - secondary --> -ENODEV
5165 * - NULL
5166 */
5167void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
5168{
5169 struct device *parent = dev->parent;
5170 struct fwnode_handle *fn = dev->fwnode;
5171
5172 if (fwnode) {
5173 if (fwnode_is_primary(fn))
5174 fn = fn->secondary;
5175
5176 if (fn) {
5177 WARN_ON(fwnode->secondary);
5178 fwnode->secondary = fn;
5179 }
5180 dev->fwnode = fwnode;
5181 } else {
5182 if (fwnode_is_primary(fn)) {
5183 dev->fwnode = fn->secondary;
5184
5185 /* Skip nullifying fn->secondary if the primary is shared */
5186 if (parent && fn == parent->fwnode)
5187 return;
5188
5189 /* Set fn->secondary = NULL, so fn remains the primary fwnode */
5190 fn->secondary = NULL;
5191 } else {
5192 dev->fwnode = NULL;
5193 }
5194 }
5195}
5196EXPORT_SYMBOL_GPL(set_primary_fwnode);
5197
5198/**
5199 * set_secondary_fwnode - Change the secondary firmware node of a given device.
5200 * @dev: Device to handle.
5201 * @fwnode: New secondary firmware node of the device.
5202 *
5203 * If a primary firmware node of the device is present, set its secondary
5204 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
5205 * @fwnode.
5206 */
5207void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
5208{
5209 if (fwnode)
5210 fwnode->secondary = ERR_PTR(-ENODEV);
5211
5212 if (fwnode_is_primary(dev->fwnode))
5213 dev->fwnode->secondary = fwnode;
5214 else
5215 dev->fwnode = fwnode;
5216}
5217EXPORT_SYMBOL_GPL(set_secondary_fwnode);
5218
5219/**
5220 * device_set_of_node_from_dev - reuse device-tree node of another device
5221 * @dev: device whose device-tree node is being set
5222 * @dev2: device whose device-tree node is being reused
5223 *
5224 * Takes another reference to the new device-tree node after first dropping
5225 * any reference held to the old node.
5226 */
5227void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
5228{
5229 of_node_put(dev->of_node);
5230 dev->of_node = of_node_get(dev2->of_node);
5231 dev->of_node_reused = true;
5232}
5233EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
5234
5235void device_set_node(struct device *dev, struct fwnode_handle *fwnode)
5236{
5237 dev->fwnode = fwnode;
5238 dev->of_node = to_of_node(fwnode);
5239}
5240EXPORT_SYMBOL_GPL(device_set_node);
5241
5242int device_match_name(struct device *dev, const void *name)
5243{
5244 return sysfs_streq(dev_name(dev), name);
5245}
5246EXPORT_SYMBOL_GPL(device_match_name);
5247
5248int device_match_of_node(struct device *dev, const void *np)
5249{
5250 return dev->of_node == np;
5251}
5252EXPORT_SYMBOL_GPL(device_match_of_node);
5253
5254int device_match_fwnode(struct device *dev, const void *fwnode)
5255{
5256 return dev_fwnode(dev) == fwnode;
5257}
5258EXPORT_SYMBOL_GPL(device_match_fwnode);
5259
5260int device_match_devt(struct device *dev, const void *pdevt)
5261{
5262 return dev->devt == *(dev_t *)pdevt;
5263}
5264EXPORT_SYMBOL_GPL(device_match_devt);
5265
5266int device_match_acpi_dev(struct device *dev, const void *adev)
5267{
5268 return ACPI_COMPANION(dev) == adev;
5269}
5270EXPORT_SYMBOL(device_match_acpi_dev);
5271
5272int device_match_acpi_handle(struct device *dev, const void *handle)
5273{
5274 return ACPI_HANDLE(dev) == handle;
5275}
5276EXPORT_SYMBOL(device_match_acpi_handle);
5277
5278int device_match_any(struct device *dev, const void *unused)
5279{
5280 return 1;
5281}
5282EXPORT_SYMBOL_GPL(device_match_any);