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