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;
47
48/**
49 * __fwnode_link_add - Create a link between two fwnode_handles.
50 * @con: Consumer end of the link.
51 * @sup: Supplier end of the link.
52 * @flags: Link flags.
53 *
54 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
55 * represents the detail that the firmware lists @sup fwnode as supplying a
56 * resource to @con.
57 *
58 * The driver core will use the fwnode link to create a device link between the
59 * two device objects corresponding to @con and @sup when they are created. The
60 * driver core will automatically delete the fwnode link between @con and @sup
61 * after doing that.
62 *
63 * Attempts to create duplicate links between the same pair of fwnode handles
64 * are ignored and there is no reference counting.
65 */
66static int __fwnode_link_add(struct fwnode_handle *con,
67 struct fwnode_handle *sup, u8 flags)
68{
69 struct fwnode_link *link;
70
71 list_for_each_entry(link, &sup->consumers, s_hook)
72 if (link->consumer == con) {
73 link->flags |= flags;
74 return 0;
75 }
76
77 link = kzalloc(size: sizeof(*link), GFP_KERNEL);
78 if (!link)
79 return -ENOMEM;
80
81 link->supplier = sup;
82 INIT_LIST_HEAD(list: &link->s_hook);
83 link->consumer = con;
84 INIT_LIST_HEAD(list: &link->c_hook);
85 link->flags = flags;
86
87 list_add(new: &link->s_hook, head: &sup->consumers);
88 list_add(new: &link->c_hook, head: &con->suppliers);
89 pr_debug("%pfwf Linked as a fwnode consumer to %pfwf\n",
90 con, sup);
91
92 return 0;
93}
94
95int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
96{
97 int ret;
98
99 mutex_lock(&fwnode_link_lock);
100 ret = __fwnode_link_add(con, sup, flags: 0);
101 mutex_unlock(lock: &fwnode_link_lock);
102 return ret;
103}
104
105/**
106 * __fwnode_link_del - Delete a link between two fwnode_handles.
107 * @link: the fwnode_link to be deleted
108 *
109 * The fwnode_link_lock needs to be held when this function is called.
110 */
111static void __fwnode_link_del(struct fwnode_link *link)
112{
113 pr_debug("%pfwf Dropping the fwnode link to %pfwf\n",
114 link->consumer, link->supplier);
115 list_del(entry: &link->s_hook);
116 list_del(entry: &link->c_hook);
117 kfree(objp: link);
118}
119
120/**
121 * __fwnode_link_cycle - Mark a fwnode link as being part of a cycle.
122 * @link: the fwnode_link to be marked
123 *
124 * The fwnode_link_lock needs to be held when this function is called.
125 */
126static void __fwnode_link_cycle(struct fwnode_link *link)
127{
128 pr_debug("%pfwf: Relaxing link with %pfwf\n",
129 link->consumer, link->supplier);
130 link->flags |= FWLINK_FLAG_CYCLE;
131}
132
133/**
134 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
135 * @fwnode: fwnode whose supplier links need to be deleted
136 *
137 * Deletes all supplier links connecting directly to @fwnode.
138 */
139static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
140{
141 struct fwnode_link *link, *tmp;
142
143 mutex_lock(&fwnode_link_lock);
144 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook)
145 __fwnode_link_del(link);
146 mutex_unlock(lock: &fwnode_link_lock);
147}
148
149/**
150 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle.
151 * @fwnode: fwnode whose consumer links need to be deleted
152 *
153 * Deletes all consumer links connecting directly to @fwnode.
154 */
155static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
156{
157 struct fwnode_link *link, *tmp;
158
159 mutex_lock(&fwnode_link_lock);
160 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook)
161 __fwnode_link_del(link);
162 mutex_unlock(lock: &fwnode_link_lock);
163}
164
165/**
166 * fwnode_links_purge - Delete all links connected to a fwnode_handle.
167 * @fwnode: fwnode whose links needs to be deleted
168 *
169 * Deletes all links connecting directly to a fwnode.
170 */
171void fwnode_links_purge(struct fwnode_handle *fwnode)
172{
173 fwnode_links_purge_suppliers(fwnode);
174 fwnode_links_purge_consumers(fwnode);
175}
176
177void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
178{
179 struct fwnode_handle *child;
180
181 /* Don't purge consumer links of an added child */
182 if (fwnode->dev)
183 return;
184
185 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
186 fwnode_links_purge_consumers(fwnode);
187
188 fwnode_for_each_available_child_node(fwnode, child)
189 fw_devlink_purge_absent_suppliers(fwnode: child);
190}
191EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
192
193/**
194 * __fwnode_links_move_consumers - Move consumer from @from to @to fwnode_handle
195 * @from: move consumers away from this fwnode
196 * @to: move consumers to this fwnode
197 *
198 * Move all consumer links from @from fwnode to @to fwnode.
199 */
200static void __fwnode_links_move_consumers(struct fwnode_handle *from,
201 struct fwnode_handle *to)
202{
203 struct fwnode_link *link, *tmp;
204
205 list_for_each_entry_safe(link, tmp, &from->consumers, s_hook) {
206 __fwnode_link_add(con: link->consumer, sup: to, flags: link->flags);
207 __fwnode_link_del(link);
208 }
209}
210
211/**
212 * __fw_devlink_pickup_dangling_consumers - Pick up dangling consumers
213 * @fwnode: fwnode from which to pick up dangling consumers
214 * @new_sup: fwnode of new supplier
215 *
216 * If the @fwnode has a corresponding struct device and the device supports
217 * probing (that is, added to a bus), then we want to let fw_devlink create
218 * MANAGED device links to this device, so leave @fwnode and its descendant's
219 * fwnode links alone.
220 *
221 * Otherwise, move its consumers to the new supplier @new_sup.
222 */
223static void __fw_devlink_pickup_dangling_consumers(struct fwnode_handle *fwnode,
224 struct fwnode_handle *new_sup)
225{
226 struct fwnode_handle *child;
227
228 if (fwnode->dev && fwnode->dev->bus)
229 return;
230
231 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
232 __fwnode_links_move_consumers(from: fwnode, to: new_sup);
233
234 fwnode_for_each_available_child_node(fwnode, child)
235 __fw_devlink_pickup_dangling_consumers(fwnode: child, new_sup);
236}
237
238static DEFINE_MUTEX(device_links_lock);
239DEFINE_STATIC_SRCU(device_links_srcu);
240
241static inline void device_links_write_lock(void)
242{
243 mutex_lock(&device_links_lock);
244}
245
246static inline void device_links_write_unlock(void)
247{
248 mutex_unlock(lock: &device_links_lock);
249}
250
251int device_links_read_lock(void) __acquires(&device_links_srcu)
252{
253 return srcu_read_lock(ssp: &device_links_srcu);
254}
255
256void device_links_read_unlock(int idx) __releases(&device_links_srcu)
257{
258 srcu_read_unlock(ssp: &device_links_srcu, idx);
259}
260
261int device_links_read_lock_held(void)
262{
263 return srcu_read_lock_held(ssp: &device_links_srcu);
264}
265
266static void device_link_synchronize_removal(void)
267{
268 synchronize_srcu(ssp: &device_links_srcu);
269}
270
271static void device_link_remove_from_lists(struct device_link *link)
272{
273 list_del_rcu(entry: &link->s_node);
274 list_del_rcu(entry: &link->c_node);
275}
276
277static bool device_is_ancestor(struct device *dev, struct device *target)
278{
279 while (target->parent) {
280 target = target->parent;
281 if (dev == target)
282 return true;
283 }
284 return false;
285}
286
287static inline bool device_link_flag_is_sync_state_only(u32 flags)
288{
289 return (flags & ~(DL_FLAG_INFERRED | DL_FLAG_CYCLE)) ==
290 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED);
291}
292
293/**
294 * device_is_dependent - Check if one device depends on another one
295 * @dev: Device to check dependencies for.
296 * @target: Device to check against.
297 *
298 * Check if @target depends on @dev or any device dependent on it (its child or
299 * its consumer etc). Return 1 if that is the case or 0 otherwise.
300 */
301int device_is_dependent(struct device *dev, void *target)
302{
303 struct device_link *link;
304 int ret;
305
306 /*
307 * The "ancestors" check is needed to catch the case when the target
308 * device has not been completely initialized yet and it is still
309 * missing from the list of children of its parent device.
310 */
311 if (dev == target || device_is_ancestor(dev, target))
312 return 1;
313
314 ret = device_for_each_child(dev, data: target, fn: device_is_dependent);
315 if (ret)
316 return ret;
317
318 list_for_each_entry(link, &dev->links.consumers, s_node) {
319 if (device_link_flag_is_sync_state_only(flags: link->flags))
320 continue;
321
322 if (link->consumer == target)
323 return 1;
324
325 ret = device_is_dependent(dev: link->consumer, target);
326 if (ret)
327 break;
328 }
329 return ret;
330}
331
332static void device_link_init_status(struct device_link *link,
333 struct device *consumer,
334 struct device *supplier)
335{
336 switch (supplier->links.status) {
337 case DL_DEV_PROBING:
338 switch (consumer->links.status) {
339 case DL_DEV_PROBING:
340 /*
341 * A consumer driver can create a link to a supplier
342 * that has not completed its probing yet as long as it
343 * knows that the supplier is already functional (for
344 * example, it has just acquired some resources from the
345 * supplier).
346 */
347 link->status = DL_STATE_CONSUMER_PROBE;
348 break;
349 default:
350 link->status = DL_STATE_DORMANT;
351 break;
352 }
353 break;
354 case DL_DEV_DRIVER_BOUND:
355 switch (consumer->links.status) {
356 case DL_DEV_PROBING:
357 link->status = DL_STATE_CONSUMER_PROBE;
358 break;
359 case DL_DEV_DRIVER_BOUND:
360 link->status = DL_STATE_ACTIVE;
361 break;
362 default:
363 link->status = DL_STATE_AVAILABLE;
364 break;
365 }
366 break;
367 case DL_DEV_UNBINDING:
368 link->status = DL_STATE_SUPPLIER_UNBIND;
369 break;
370 default:
371 link->status = DL_STATE_DORMANT;
372 break;
373 }
374}
375
376static int device_reorder_to_tail(struct device *dev, void *not_used)
377{
378 struct device_link *link;
379
380 /*
381 * Devices that have not been registered yet will be put to the ends
382 * of the lists during the registration, so skip them here.
383 */
384 if (device_is_registered(dev))
385 devices_kset_move_last(dev);
386
387 if (device_pm_initialized(dev))
388 device_pm_move_last(dev);
389
390 device_for_each_child(dev, NULL, fn: device_reorder_to_tail);
391 list_for_each_entry(link, &dev->links.consumers, s_node) {
392 if (device_link_flag_is_sync_state_only(flags: link->flags))
393 continue;
394 device_reorder_to_tail(dev: link->consumer, NULL);
395 }
396
397 return 0;
398}
399
400/**
401 * device_pm_move_to_tail - Move set of devices to the end of device lists
402 * @dev: Device to move
403 *
404 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
405 *
406 * It moves the @dev along with all of its children and all of its consumers
407 * to the ends of the device_kset and dpm_list, recursively.
408 */
409void device_pm_move_to_tail(struct device *dev)
410{
411 int idx;
412
413 idx = device_links_read_lock();
414 device_pm_lock();
415 device_reorder_to_tail(dev, NULL);
416 device_pm_unlock();
417 device_links_read_unlock(idx);
418}
419
420#define to_devlink(dev) container_of((dev), struct device_link, link_dev)
421
422static ssize_t status_show(struct device *dev,
423 struct device_attribute *attr, char *buf)
424{
425 const char *output;
426
427 switch (to_devlink(dev)->status) {
428 case DL_STATE_NONE:
429 output = "not tracked";
430 break;
431 case DL_STATE_DORMANT:
432 output = "dormant";
433 break;
434 case DL_STATE_AVAILABLE:
435 output = "available";
436 break;
437 case DL_STATE_CONSUMER_PROBE:
438 output = "consumer probing";
439 break;
440 case DL_STATE_ACTIVE:
441 output = "active";
442 break;
443 case DL_STATE_SUPPLIER_UNBIND:
444 output = "supplier unbinding";
445 break;
446 default:
447 output = "unknown";
448 break;
449 }
450
451 return sysfs_emit(buf, fmt: "%s\n", output);
452}
453static DEVICE_ATTR_RO(status);
454
455static ssize_t auto_remove_on_show(struct device *dev,
456 struct device_attribute *attr, char *buf)
457{
458 struct device_link *link = to_devlink(dev);
459 const char *output;
460
461 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
462 output = "supplier unbind";
463 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
464 output = "consumer unbind";
465 else
466 output = "never";
467
468 return sysfs_emit(buf, fmt: "%s\n", output);
469}
470static DEVICE_ATTR_RO(auto_remove_on);
471
472static ssize_t runtime_pm_show(struct device *dev,
473 struct device_attribute *attr, char *buf)
474{
475 struct device_link *link = to_devlink(dev);
476
477 return sysfs_emit(buf, fmt: "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
478}
479static DEVICE_ATTR_RO(runtime_pm);
480
481static ssize_t sync_state_only_show(struct device *dev,
482 struct device_attribute *attr, char *buf)
483{
484 struct device_link *link = to_devlink(dev);
485
486 return sysfs_emit(buf, fmt: "%d\n",
487 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
488}
489static DEVICE_ATTR_RO(sync_state_only);
490
491static struct attribute *devlink_attrs[] = {
492 &dev_attr_status.attr,
493 &dev_attr_auto_remove_on.attr,
494 &dev_attr_runtime_pm.attr,
495 &dev_attr_sync_state_only.attr,
496 NULL,
497};
498ATTRIBUTE_GROUPS(devlink);
499
500static void device_link_release_fn(struct work_struct *work)
501{
502 struct device_link *link = container_of(work, struct device_link, rm_work);
503
504 /* Ensure that all references to the link object have been dropped. */
505 device_link_synchronize_removal();
506
507 pm_runtime_release_supplier(link);
508 /*
509 * If supplier_preactivated is set, the link has been dropped between
510 * the pm_runtime_get_suppliers() and pm_runtime_put_suppliers() calls
511 * in __driver_probe_device(). In that case, drop the supplier's
512 * PM-runtime usage counter to remove the reference taken by
513 * pm_runtime_get_suppliers().
514 */
515 if (link->supplier_preactivated)
516 pm_runtime_put_noidle(dev: link->supplier);
517
518 pm_request_idle(dev: link->supplier);
519
520 put_device(dev: link->consumer);
521 put_device(dev: link->supplier);
522 kfree(objp: link);
523}
524
525static void devlink_dev_release(struct device *dev)
526{
527 struct device_link *link = to_devlink(dev);
528
529 INIT_WORK(&link->rm_work, device_link_release_fn);
530 /*
531 * It may take a while to complete this work because of the SRCU
532 * synchronization in device_link_release_fn() and if the consumer or
533 * supplier devices get deleted when it runs, so put it into the "long"
534 * workqueue.
535 */
536 queue_work(wq: system_long_wq, work: &link->rm_work);
537}
538
539static struct class devlink_class = {
540 .name = "devlink",
541 .dev_groups = devlink_groups,
542 .dev_release = devlink_dev_release,
543};
544
545static int devlink_add_symlinks(struct device *dev)
546{
547 int ret;
548 size_t len;
549 struct device_link *link = to_devlink(dev);
550 struct device *sup = link->supplier;
551 struct device *con = link->consumer;
552 char *buf;
553
554 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
555 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
556 len += strlen(":");
557 len += strlen("supplier:") + 1;
558 buf = kzalloc(size: len, GFP_KERNEL);
559 if (!buf)
560 return -ENOMEM;
561
562 ret = sysfs_create_link(kobj: &link->link_dev.kobj, target: &sup->kobj, name: "supplier");
563 if (ret)
564 goto out;
565
566 ret = sysfs_create_link(kobj: &link->link_dev.kobj, target: &con->kobj, name: "consumer");
567 if (ret)
568 goto err_con;
569
570 snprintf(buf, size: len, fmt: "consumer:%s:%s", dev_bus_name(dev: con), dev_name(dev: con));
571 ret = sysfs_create_link(kobj: &sup->kobj, target: &link->link_dev.kobj, name: buf);
572 if (ret)
573 goto err_con_dev;
574
575 snprintf(buf, size: len, fmt: "supplier:%s:%s", dev_bus_name(dev: sup), dev_name(dev: sup));
576 ret = sysfs_create_link(kobj: &con->kobj, target: &link->link_dev.kobj, name: buf);
577 if (ret)
578 goto err_sup_dev;
579
580 goto out;
581
582err_sup_dev:
583 snprintf(buf, size: len, fmt: "consumer:%s:%s", dev_bus_name(dev: con), dev_name(dev: con));
584 sysfs_remove_link(kobj: &sup->kobj, name: buf);
585err_con_dev:
586 sysfs_remove_link(kobj: &link->link_dev.kobj, name: "consumer");
587err_con:
588 sysfs_remove_link(kobj: &link->link_dev.kobj, name: "supplier");
589out:
590 kfree(objp: buf);
591 return ret;
592}
593
594static void devlink_remove_symlinks(struct device *dev)
595{
596 struct device_link *link = to_devlink(dev);
597 size_t len;
598 struct device *sup = link->supplier;
599 struct device *con = link->consumer;
600 char *buf;
601
602 sysfs_remove_link(kobj: &link->link_dev.kobj, name: "consumer");
603 sysfs_remove_link(kobj: &link->link_dev.kobj, name: "supplier");
604
605 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
606 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
607 len += strlen(":");
608 len += strlen("supplier:") + 1;
609 buf = kzalloc(size: len, GFP_KERNEL);
610 if (!buf) {
611 WARN(1, "Unable to properly free device link symlinks!\n");
612 return;
613 }
614
615 if (device_is_registered(dev: con)) {
616 snprintf(buf, size: len, fmt: "supplier:%s:%s", dev_bus_name(dev: sup), dev_name(dev: sup));
617 sysfs_remove_link(kobj: &con->kobj, name: buf);
618 }
619 snprintf(buf, size: len, fmt: "consumer:%s:%s", dev_bus_name(dev: con), dev_name(dev: con));
620 sysfs_remove_link(kobj: &sup->kobj, name: buf);
621 kfree(objp: buf);
622}
623
624static struct class_interface devlink_class_intf = {
625 .class = &devlink_class,
626 .add_dev = devlink_add_symlinks,
627 .remove_dev = devlink_remove_symlinks,
628};
629
630static int __init devlink_class_init(void)
631{
632 int ret;
633
634 ret = class_register(class: &devlink_class);
635 if (ret)
636 return ret;
637
638 ret = class_interface_register(&devlink_class_intf);
639 if (ret)
640 class_unregister(class: &devlink_class);
641
642 return ret;
643}
644postcore_initcall(devlink_class_init);
645
646#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
647 DL_FLAG_AUTOREMOVE_SUPPLIER | \
648 DL_FLAG_AUTOPROBE_CONSUMER | \
649 DL_FLAG_SYNC_STATE_ONLY | \
650 DL_FLAG_INFERRED | \
651 DL_FLAG_CYCLE)
652
653#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
654 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
655
656/**
657 * device_link_add - Create a link between two devices.
658 * @consumer: Consumer end of the link.
659 * @supplier: Supplier end of the link.
660 * @flags: Link flags.
661 *
662 * The caller is responsible for the proper synchronization of the link creation
663 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
664 * runtime PM framework to take the link into account. Second, if the
665 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
666 * be forced into the active meta state and reference-counted upon the creation
667 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
668 * ignored.
669 *
670 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
671 * expected to release the link returned by it directly with the help of either
672 * device_link_del() or device_link_remove().
673 *
674 * If that flag is not set, however, the caller of this function is handing the
675 * management of the link over to the driver core entirely and its return value
676 * can only be used to check whether or not the link is present. In that case,
677 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
678 * flags can be used to indicate to the driver core when the link can be safely
679 * deleted. Namely, setting one of them in @flags indicates to the driver core
680 * that the link is not going to be used (by the given caller of this function)
681 * after unbinding the consumer or supplier driver, respectively, from its
682 * device, so the link can be deleted at that point. If none of them is set,
683 * the link will be maintained until one of the devices pointed to by it (either
684 * the consumer or the supplier) is unregistered.
685 *
686 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
687 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
688 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
689 * be used to request the driver core to automatically probe for a consumer
690 * driver after successfully binding a driver to the supplier device.
691 *
692 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
693 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
694 * the same time is invalid and will cause NULL to be returned upfront.
695 * However, if a device link between the given @consumer and @supplier pair
696 * exists already when this function is called for them, the existing link will
697 * be returned regardless of its current type and status (the link's flags may
698 * be modified then). The caller of this function is then expected to treat
699 * the link as though it has just been created, so (in particular) if
700 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
701 * explicitly when not needed any more (as stated above).
702 *
703 * A side effect of the link creation is re-ordering of dpm_list and the
704 * devices_kset list by moving the consumer device and all devices depending
705 * on it to the ends of these lists (that does not happen to devices that have
706 * not been registered when this function is called).
707 *
708 * The supplier device is required to be registered when this function is called
709 * and NULL will be returned if that is not the case. The consumer device need
710 * not be registered, however.
711 */
712struct device_link *device_link_add(struct device *consumer,
713 struct device *supplier, u32 flags)
714{
715 struct device_link *link;
716
717 if (!consumer || !supplier || consumer == supplier ||
718 flags & ~DL_ADD_VALID_FLAGS ||
719 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
720 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
721 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
722 DL_FLAG_AUTOREMOVE_SUPPLIER)))
723 return NULL;
724
725 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
726 if (pm_runtime_get_sync(dev: supplier) < 0) {
727 pm_runtime_put_noidle(dev: supplier);
728 return NULL;
729 }
730 }
731
732 if (!(flags & DL_FLAG_STATELESS))
733 flags |= DL_FLAG_MANAGED;
734
735 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
736 !device_link_flag_is_sync_state_only(flags))
737 return NULL;
738
739 device_links_write_lock();
740 device_pm_lock();
741
742 /*
743 * If the supplier has not been fully registered yet or there is a
744 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
745 * the supplier already in the graph, return NULL. If the link is a
746 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
747 * because it only affects sync_state() callbacks.
748 */
749 if (!device_pm_initialized(dev: supplier)
750 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
751 device_is_dependent(dev: consumer, target: supplier))) {
752 link = NULL;
753 goto out;
754 }
755
756 /*
757 * SYNC_STATE_ONLY links are useless once a consumer device has probed.
758 * So, only create it if the consumer hasn't probed yet.
759 */
760 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
761 consumer->links.status != DL_DEV_NO_DRIVER &&
762 consumer->links.status != DL_DEV_PROBING) {
763 link = NULL;
764 goto out;
765 }
766
767 /*
768 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
769 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
770 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
771 */
772 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
773 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
774
775 list_for_each_entry(link, &supplier->links.consumers, s_node) {
776 if (link->consumer != consumer)
777 continue;
778
779 if (link->flags & DL_FLAG_INFERRED &&
780 !(flags & DL_FLAG_INFERRED))
781 link->flags &= ~DL_FLAG_INFERRED;
782
783 if (flags & DL_FLAG_PM_RUNTIME) {
784 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
785 pm_runtime_new_link(dev: consumer);
786 link->flags |= DL_FLAG_PM_RUNTIME;
787 }
788 if (flags & DL_FLAG_RPM_ACTIVE)
789 refcount_inc(r: &link->rpm_active);
790 }
791
792 if (flags & DL_FLAG_STATELESS) {
793 kref_get(kref: &link->kref);
794 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
795 !(link->flags & DL_FLAG_STATELESS)) {
796 link->flags |= DL_FLAG_STATELESS;
797 goto reorder;
798 } else {
799 link->flags |= DL_FLAG_STATELESS;
800 goto out;
801 }
802 }
803
804 /*
805 * If the life time of the link following from the new flags is
806 * longer than indicated by the flags of the existing link,
807 * update the existing link to stay around longer.
808 */
809 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
810 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
811 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
812 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
813 }
814 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
815 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
816 DL_FLAG_AUTOREMOVE_SUPPLIER);
817 }
818 if (!(link->flags & DL_FLAG_MANAGED)) {
819 kref_get(kref: &link->kref);
820 link->flags |= DL_FLAG_MANAGED;
821 device_link_init_status(link, consumer, supplier);
822 }
823 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
824 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
825 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
826 goto reorder;
827 }
828
829 goto out;
830 }
831
832 link = kzalloc(size: sizeof(*link), GFP_KERNEL);
833 if (!link)
834 goto out;
835
836 refcount_set(r: &link->rpm_active, n: 1);
837
838 get_device(dev: supplier);
839 link->supplier = supplier;
840 INIT_LIST_HEAD(list: &link->s_node);
841 get_device(dev: consumer);
842 link->consumer = consumer;
843 INIT_LIST_HEAD(list: &link->c_node);
844 link->flags = flags;
845 kref_init(kref: &link->kref);
846
847 link->link_dev.class = &devlink_class;
848 device_set_pm_not_required(dev: &link->link_dev);
849 dev_set_name(dev: &link->link_dev, name: "%s:%s--%s:%s",
850 dev_bus_name(dev: supplier), dev_name(dev: supplier),
851 dev_bus_name(dev: consumer), dev_name(dev: consumer));
852 if (device_register(dev: &link->link_dev)) {
853 put_device(dev: &link->link_dev);
854 link = NULL;
855 goto out;
856 }
857
858 if (flags & DL_FLAG_PM_RUNTIME) {
859 if (flags & DL_FLAG_RPM_ACTIVE)
860 refcount_inc(r: &link->rpm_active);
861
862 pm_runtime_new_link(dev: consumer);
863 }
864
865 /* Determine the initial link state. */
866 if (flags & DL_FLAG_STATELESS)
867 link->status = DL_STATE_NONE;
868 else
869 device_link_init_status(link, consumer, supplier);
870
871 /*
872 * Some callers expect the link creation during consumer driver probe to
873 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
874 */
875 if (link->status == DL_STATE_CONSUMER_PROBE &&
876 flags & DL_FLAG_PM_RUNTIME)
877 pm_runtime_resume(dev: supplier);
878
879 list_add_tail_rcu(new: &link->s_node, head: &supplier->links.consumers);
880 list_add_tail_rcu(new: &link->c_node, head: &consumer->links.suppliers);
881
882 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
883 dev_dbg(consumer,
884 "Linked as a sync state only consumer to %s\n",
885 dev_name(supplier));
886 goto out;
887 }
888
889reorder:
890 /*
891 * Move the consumer and all of the devices depending on it to the end
892 * of dpm_list and the devices_kset list.
893 *
894 * It is necessary to hold dpm_list locked throughout all that or else
895 * we may end up suspending with a wrong ordering of it.
896 */
897 device_reorder_to_tail(dev: consumer, NULL);
898
899 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
900
901out:
902 device_pm_unlock();
903 device_links_write_unlock();
904
905 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
906 pm_runtime_put(dev: supplier);
907
908 return link;
909}
910EXPORT_SYMBOL_GPL(device_link_add);
911
912static void __device_link_del(struct kref *kref)
913{
914 struct device_link *link = container_of(kref, struct device_link, kref);
915
916 dev_dbg(link->consumer, "Dropping the link to %s\n",
917 dev_name(link->supplier));
918
919 pm_runtime_drop_link(link);
920
921 device_link_remove_from_lists(link);
922 device_unregister(dev: &link->link_dev);
923}
924
925static void device_link_put_kref(struct device_link *link)
926{
927 if (link->flags & DL_FLAG_STATELESS)
928 kref_put(kref: &link->kref, release: __device_link_del);
929 else if (!device_is_registered(dev: link->consumer))
930 __device_link_del(kref: &link->kref);
931 else
932 WARN(1, "Unable to drop a managed device link reference\n");
933}
934
935/**
936 * device_link_del - Delete a stateless link between two devices.
937 * @link: Device link to delete.
938 *
939 * The caller must ensure proper synchronization of this function with runtime
940 * PM. If the link was added multiple times, it needs to be deleted as often.
941 * Care is required for hotplugged devices: Their links are purged on removal
942 * and calling device_link_del() is then no longer allowed.
943 */
944void device_link_del(struct device_link *link)
945{
946 device_links_write_lock();
947 device_link_put_kref(link);
948 device_links_write_unlock();
949}
950EXPORT_SYMBOL_GPL(device_link_del);
951
952/**
953 * device_link_remove - Delete a stateless link between two devices.
954 * @consumer: Consumer end of the link.
955 * @supplier: Supplier end of the link.
956 *
957 * The caller must ensure proper synchronization of this function with runtime
958 * PM.
959 */
960void device_link_remove(void *consumer, struct device *supplier)
961{
962 struct device_link *link;
963
964 if (WARN_ON(consumer == supplier))
965 return;
966
967 device_links_write_lock();
968
969 list_for_each_entry(link, &supplier->links.consumers, s_node) {
970 if (link->consumer == consumer) {
971 device_link_put_kref(link);
972 break;
973 }
974 }
975
976 device_links_write_unlock();
977}
978EXPORT_SYMBOL_GPL(device_link_remove);
979
980static void device_links_missing_supplier(struct device *dev)
981{
982 struct device_link *link;
983
984 list_for_each_entry(link, &dev->links.suppliers, c_node) {
985 if (link->status != DL_STATE_CONSUMER_PROBE)
986 continue;
987
988 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
989 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
990 } else {
991 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
992 WRITE_ONCE(link->status, DL_STATE_DORMANT);
993 }
994 }
995}
996
997static bool dev_is_best_effort(struct device *dev)
998{
999 return (fw_devlink_best_effort && dev->can_match) ||
1000 (dev->fwnode && (dev->fwnode->flags & FWNODE_FLAG_BEST_EFFORT));
1001}
1002
1003static struct fwnode_handle *fwnode_links_check_suppliers(
1004 struct fwnode_handle *fwnode)
1005{
1006 struct fwnode_link *link;
1007
1008 if (!fwnode || fw_devlink_is_permissive())
1009 return NULL;
1010
1011 list_for_each_entry(link, &fwnode->suppliers, c_hook)
1012 if (!(link->flags & FWLINK_FLAG_CYCLE))
1013 return link->supplier;
1014
1015 return NULL;
1016}
1017
1018/**
1019 * device_links_check_suppliers - Check presence of supplier drivers.
1020 * @dev: Consumer device.
1021 *
1022 * Check links from this device to any suppliers. Walk the list of the device's
1023 * links to suppliers and see if all of them are available. If not, simply
1024 * return -EPROBE_DEFER.
1025 *
1026 * We need to guarantee that the supplier will not go away after the check has
1027 * been positive here. It only can go away in __device_release_driver() and
1028 * that function checks the device's links to consumers. This means we need to
1029 * mark the link as "consumer probe in progress" to make the supplier removal
1030 * wait for us to complete (or bad things may happen).
1031 *
1032 * Links without the DL_FLAG_MANAGED flag set are ignored.
1033 */
1034int device_links_check_suppliers(struct device *dev)
1035{
1036 struct device_link *link;
1037 int ret = 0, fwnode_ret = 0;
1038 struct fwnode_handle *sup_fw;
1039
1040 /*
1041 * Device waiting for supplier to become available is not allowed to
1042 * probe.
1043 */
1044 mutex_lock(&fwnode_link_lock);
1045 sup_fw = fwnode_links_check_suppliers(fwnode: dev->fwnode);
1046 if (sup_fw) {
1047 if (!dev_is_best_effort(dev)) {
1048 fwnode_ret = -EPROBE_DEFER;
1049 dev_err_probe(dev, err: -EPROBE_DEFER,
1050 fmt: "wait for supplier %pfwf\n", sup_fw);
1051 } else {
1052 fwnode_ret = -EAGAIN;
1053 }
1054 }
1055 mutex_unlock(lock: &fwnode_link_lock);
1056 if (fwnode_ret == -EPROBE_DEFER)
1057 return fwnode_ret;
1058
1059 device_links_write_lock();
1060
1061 list_for_each_entry(link, &dev->links.suppliers, c_node) {
1062 if (!(link->flags & DL_FLAG_MANAGED))
1063 continue;
1064
1065 if (link->status != DL_STATE_AVAILABLE &&
1066 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
1067
1068 if (dev_is_best_effort(dev) &&
1069 link->flags & DL_FLAG_INFERRED &&
1070 !link->supplier->can_match) {
1071 ret = -EAGAIN;
1072 continue;
1073 }
1074
1075 device_links_missing_supplier(dev);
1076 dev_err_probe(dev, err: -EPROBE_DEFER,
1077 fmt: "supplier %s not ready\n",
1078 dev_name(dev: link->supplier));
1079 ret = -EPROBE_DEFER;
1080 break;
1081 }
1082 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1083 }
1084 dev->links.status = DL_DEV_PROBING;
1085
1086 device_links_write_unlock();
1087
1088 return ret ? ret : fwnode_ret;
1089}
1090
1091/**
1092 * __device_links_queue_sync_state - Queue a device for sync_state() callback
1093 * @dev: Device to call sync_state() on
1094 * @list: List head to queue the @dev on
1095 *
1096 * Queues a device for a sync_state() callback when the device links write lock
1097 * isn't held. This allows the sync_state() execution flow to use device links
1098 * APIs. The caller must ensure this function is called with
1099 * device_links_write_lock() held.
1100 *
1101 * This function does a get_device() to make sure the device is not freed while
1102 * on this list.
1103 *
1104 * So the caller must also ensure that device_links_flush_sync_list() is called
1105 * as soon as the caller releases device_links_write_lock(). This is necessary
1106 * to make sure the sync_state() is called in a timely fashion and the
1107 * put_device() is called on this device.
1108 */
1109static void __device_links_queue_sync_state(struct device *dev,
1110 struct list_head *list)
1111{
1112 struct device_link *link;
1113
1114 if (!dev_has_sync_state(dev))
1115 return;
1116 if (dev->state_synced)
1117 return;
1118
1119 list_for_each_entry(link, &dev->links.consumers, s_node) {
1120 if (!(link->flags & DL_FLAG_MANAGED))
1121 continue;
1122 if (link->status != DL_STATE_ACTIVE)
1123 return;
1124 }
1125
1126 /*
1127 * Set the flag here to avoid adding the same device to a list more
1128 * than once. This can happen if new consumers get added to the device
1129 * and probed before the list is flushed.
1130 */
1131 dev->state_synced = true;
1132
1133 if (WARN_ON(!list_empty(&dev->links.defer_sync)))
1134 return;
1135
1136 get_device(dev);
1137 list_add_tail(new: &dev->links.defer_sync, head: list);
1138}
1139
1140/**
1141 * device_links_flush_sync_list - Call sync_state() on a list of devices
1142 * @list: List of devices to call sync_state() on
1143 * @dont_lock_dev: Device for which lock is already held by the caller
1144 *
1145 * Calls sync_state() on all the devices that have been queued for it. This
1146 * function is used in conjunction with __device_links_queue_sync_state(). The
1147 * @dont_lock_dev parameter is useful when this function is called from a
1148 * context where a device lock is already held.
1149 */
1150static void device_links_flush_sync_list(struct list_head *list,
1151 struct device *dont_lock_dev)
1152{
1153 struct device *dev, *tmp;
1154
1155 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
1156 list_del_init(entry: &dev->links.defer_sync);
1157
1158 if (dev != dont_lock_dev)
1159 device_lock(dev);
1160
1161 dev_sync_state(dev);
1162
1163 if (dev != dont_lock_dev)
1164 device_unlock(dev);
1165
1166 put_device(dev);
1167 }
1168}
1169
1170void device_links_supplier_sync_state_pause(void)
1171{
1172 device_links_write_lock();
1173 defer_sync_state_count++;
1174 device_links_write_unlock();
1175}
1176
1177void device_links_supplier_sync_state_resume(void)
1178{
1179 struct device *dev, *tmp;
1180 LIST_HEAD(sync_list);
1181
1182 device_links_write_lock();
1183 if (!defer_sync_state_count) {
1184 WARN(true, "Unmatched sync_state pause/resume!");
1185 goto out;
1186 }
1187 defer_sync_state_count--;
1188 if (defer_sync_state_count)
1189 goto out;
1190
1191 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
1192 /*
1193 * Delete from deferred_sync list before queuing it to
1194 * sync_list because defer_sync is used for both lists.
1195 */
1196 list_del_init(entry: &dev->links.defer_sync);
1197 __device_links_queue_sync_state(dev, list: &sync_list);
1198 }
1199out:
1200 device_links_write_unlock();
1201
1202 device_links_flush_sync_list(list: &sync_list, NULL);
1203}
1204
1205static int sync_state_resume_initcall(void)
1206{
1207 device_links_supplier_sync_state_resume();
1208 return 0;
1209}
1210late_initcall(sync_state_resume_initcall);
1211
1212static void __device_links_supplier_defer_sync(struct device *sup)
1213{
1214 if (list_empty(head: &sup->links.defer_sync) && dev_has_sync_state(dev: sup))
1215 list_add_tail(new: &sup->links.defer_sync, head: &deferred_sync);
1216}
1217
1218static void device_link_drop_managed(struct device_link *link)
1219{
1220 link->flags &= ~DL_FLAG_MANAGED;
1221 WRITE_ONCE(link->status, DL_STATE_NONE);
1222 kref_put(kref: &link->kref, release: __device_link_del);
1223}
1224
1225static ssize_t waiting_for_supplier_show(struct device *dev,
1226 struct device_attribute *attr,
1227 char *buf)
1228{
1229 bool val;
1230
1231 device_lock(dev);
1232 mutex_lock(&fwnode_link_lock);
1233 val = !!fwnode_links_check_suppliers(fwnode: dev->fwnode);
1234 mutex_unlock(lock: &fwnode_link_lock);
1235 device_unlock(dev);
1236 return sysfs_emit(buf, fmt: "%u\n", val);
1237}
1238static DEVICE_ATTR_RO(waiting_for_supplier);
1239
1240/**
1241 * device_links_force_bind - Prepares device to be force bound
1242 * @dev: Consumer device.
1243 *
1244 * device_bind_driver() force binds a device to a driver without calling any
1245 * driver probe functions. So the consumer really isn't going to wait for any
1246 * supplier before it's bound to the driver. We still want the device link
1247 * states to be sensible when this happens.
1248 *
1249 * In preparation for device_bind_driver(), this function goes through each
1250 * supplier device links and checks if the supplier is bound. If it is, then
1251 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link
1252 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.
1253 */
1254void device_links_force_bind(struct device *dev)
1255{
1256 struct device_link *link, *ln;
1257
1258 device_links_write_lock();
1259
1260 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1261 if (!(link->flags & DL_FLAG_MANAGED))
1262 continue;
1263
1264 if (link->status != DL_STATE_AVAILABLE) {
1265 device_link_drop_managed(link);
1266 continue;
1267 }
1268 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1269 }
1270 dev->links.status = DL_DEV_PROBING;
1271
1272 device_links_write_unlock();
1273}
1274
1275/**
1276 * device_links_driver_bound - Update device links after probing its driver.
1277 * @dev: Device to update the links for.
1278 *
1279 * The probe has been successful, so update links from this device to any
1280 * consumers by changing their status to "available".
1281 *
1282 * Also change the status of @dev's links to suppliers to "active".
1283 *
1284 * Links without the DL_FLAG_MANAGED flag set are ignored.
1285 */
1286void device_links_driver_bound(struct device *dev)
1287{
1288 struct device_link *link, *ln;
1289 LIST_HEAD(sync_list);
1290
1291 /*
1292 * If a device binds successfully, it's expected to have created all
1293 * the device links it needs to or make new device links as it needs
1294 * them. So, fw_devlink no longer needs to create device links to any
1295 * of the device's suppliers.
1296 *
1297 * Also, if a child firmware node of this bound device is not added as a
1298 * device by now, assume it is never going to be added. Make this bound
1299 * device the fallback supplier to the dangling consumers of the child
1300 * firmware node because this bound device is probably implementing the
1301 * child firmware node functionality and we don't want the dangling
1302 * consumers to defer probe indefinitely waiting for a device for the
1303 * child firmware node.
1304 */
1305 if (dev->fwnode && dev->fwnode->dev == dev) {
1306 struct fwnode_handle *child;
1307 fwnode_links_purge_suppliers(fwnode: dev->fwnode);
1308 mutex_lock(&fwnode_link_lock);
1309 fwnode_for_each_available_child_node(dev->fwnode, child)
1310 __fw_devlink_pickup_dangling_consumers(fwnode: child,
1311 new_sup: dev->fwnode);
1312 __fw_devlink_link_to_consumers(dev);
1313 mutex_unlock(lock: &fwnode_link_lock);
1314 }
1315 device_remove_file(dev, attr: &dev_attr_waiting_for_supplier);
1316
1317 device_links_write_lock();
1318
1319 list_for_each_entry(link, &dev->links.consumers, s_node) {
1320 if (!(link->flags & DL_FLAG_MANAGED))
1321 continue;
1322
1323 /*
1324 * Links created during consumer probe may be in the "consumer
1325 * probe" state to start with if the supplier is still probing
1326 * when they are created and they may become "active" if the
1327 * consumer probe returns first. Skip them here.
1328 */
1329 if (link->status == DL_STATE_CONSUMER_PROBE ||
1330 link->status == DL_STATE_ACTIVE)
1331 continue;
1332
1333 WARN_ON(link->status != DL_STATE_DORMANT);
1334 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1335
1336 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1337 driver_deferred_probe_add(dev: link->consumer);
1338 }
1339
1340 if (defer_sync_state_count)
1341 __device_links_supplier_defer_sync(sup: dev);
1342 else
1343 __device_links_queue_sync_state(dev, list: &sync_list);
1344
1345 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1346 struct device *supplier;
1347
1348 if (!(link->flags & DL_FLAG_MANAGED))
1349 continue;
1350
1351 supplier = link->supplier;
1352 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1353 /*
1354 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1355 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1356 * save to drop the managed link completely.
1357 */
1358 device_link_drop_managed(link);
1359 } else if (dev_is_best_effort(dev) &&
1360 link->flags & DL_FLAG_INFERRED &&
1361 link->status != DL_STATE_CONSUMER_PROBE &&
1362 !link->supplier->can_match) {
1363 /*
1364 * When dev_is_best_effort() is true, we ignore device
1365 * links to suppliers that don't have a driver. If the
1366 * consumer device still managed to probe, there's no
1367 * point in maintaining a device link in a weird state
1368 * (consumer probed before supplier). So delete it.
1369 */
1370 device_link_drop_managed(link);
1371 } else {
1372 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1373 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1374 }
1375
1376 /*
1377 * This needs to be done even for the deleted
1378 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1379 * device link that was preventing the supplier from getting a
1380 * sync_state() call.
1381 */
1382 if (defer_sync_state_count)
1383 __device_links_supplier_defer_sync(sup: supplier);
1384 else
1385 __device_links_queue_sync_state(dev: supplier, list: &sync_list);
1386 }
1387
1388 dev->links.status = DL_DEV_DRIVER_BOUND;
1389
1390 device_links_write_unlock();
1391
1392 device_links_flush_sync_list(list: &sync_list, dont_lock_dev: dev);
1393}
1394
1395/**
1396 * __device_links_no_driver - Update links of a device without a driver.
1397 * @dev: Device without a drvier.
1398 *
1399 * Delete all non-persistent links from this device to any suppliers.
1400 *
1401 * Persistent links stay around, but their status is changed to "available",
1402 * unless they already are in the "supplier unbind in progress" state in which
1403 * case they need not be updated.
1404 *
1405 * Links without the DL_FLAG_MANAGED flag set are ignored.
1406 */
1407static void __device_links_no_driver(struct device *dev)
1408{
1409 struct device_link *link, *ln;
1410
1411 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1412 if (!(link->flags & DL_FLAG_MANAGED))
1413 continue;
1414
1415 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1416 device_link_drop_managed(link);
1417 continue;
1418 }
1419
1420 if (link->status != DL_STATE_CONSUMER_PROBE &&
1421 link->status != DL_STATE_ACTIVE)
1422 continue;
1423
1424 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1425 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1426 } else {
1427 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1428 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1429 }
1430 }
1431
1432 dev->links.status = DL_DEV_NO_DRIVER;
1433}
1434
1435/**
1436 * device_links_no_driver - Update links after failing driver probe.
1437 * @dev: Device whose driver has just failed to probe.
1438 *
1439 * Clean up leftover links to consumers for @dev and invoke
1440 * %__device_links_no_driver() to update links to suppliers for it as
1441 * appropriate.
1442 *
1443 * Links without the DL_FLAG_MANAGED flag set are ignored.
1444 */
1445void device_links_no_driver(struct device *dev)
1446{
1447 struct device_link *link;
1448
1449 device_links_write_lock();
1450
1451 list_for_each_entry(link, &dev->links.consumers, s_node) {
1452 if (!(link->flags & DL_FLAG_MANAGED))
1453 continue;
1454
1455 /*
1456 * The probe has failed, so if the status of the link is
1457 * "consumer probe" or "active", it must have been added by
1458 * a probing consumer while this device was still probing.
1459 * Change its state to "dormant", as it represents a valid
1460 * relationship, but it is not functionally meaningful.
1461 */
1462 if (link->status == DL_STATE_CONSUMER_PROBE ||
1463 link->status == DL_STATE_ACTIVE)
1464 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1465 }
1466
1467 __device_links_no_driver(dev);
1468
1469 device_links_write_unlock();
1470}
1471
1472/**
1473 * device_links_driver_cleanup - Update links after driver removal.
1474 * @dev: Device whose driver has just gone away.
1475 *
1476 * Update links to consumers for @dev by changing their status to "dormant" and
1477 * invoke %__device_links_no_driver() to update links to suppliers for it as
1478 * appropriate.
1479 *
1480 * Links without the DL_FLAG_MANAGED flag set are ignored.
1481 */
1482void device_links_driver_cleanup(struct device *dev)
1483{
1484 struct device_link *link, *ln;
1485
1486 device_links_write_lock();
1487
1488 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1489 if (!(link->flags & DL_FLAG_MANAGED))
1490 continue;
1491
1492 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1493 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1494
1495 /*
1496 * autoremove the links between this @dev and its consumer
1497 * devices that are not active, i.e. where the link state
1498 * has moved to DL_STATE_SUPPLIER_UNBIND.
1499 */
1500 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1501 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1502 device_link_drop_managed(link);
1503
1504 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1505 }
1506
1507 list_del_init(entry: &dev->links.defer_sync);
1508 __device_links_no_driver(dev);
1509
1510 device_links_write_unlock();
1511}
1512
1513/**
1514 * device_links_busy - Check if there are any busy links to consumers.
1515 * @dev: Device to check.
1516 *
1517 * Check each consumer of the device and return 'true' if its link's status
1518 * is one of "consumer probe" or "active" (meaning that the given consumer is
1519 * probing right now or its driver is present). Otherwise, change the link
1520 * state to "supplier unbind" to prevent the consumer from being probed
1521 * successfully going forward.
1522 *
1523 * Return 'false' if there are no probing or active consumers.
1524 *
1525 * Links without the DL_FLAG_MANAGED flag set are ignored.
1526 */
1527bool device_links_busy(struct device *dev)
1528{
1529 struct device_link *link;
1530 bool ret = false;
1531
1532 device_links_write_lock();
1533
1534 list_for_each_entry(link, &dev->links.consumers, s_node) {
1535 if (!(link->flags & DL_FLAG_MANAGED))
1536 continue;
1537
1538 if (link->status == DL_STATE_CONSUMER_PROBE
1539 || link->status == DL_STATE_ACTIVE) {
1540 ret = true;
1541 break;
1542 }
1543 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1544 }
1545
1546 dev->links.status = DL_DEV_UNBINDING;
1547
1548 device_links_write_unlock();
1549 return ret;
1550}
1551
1552/**
1553 * device_links_unbind_consumers - Force unbind consumers of the given device.
1554 * @dev: Device to unbind the consumers of.
1555 *
1556 * Walk the list of links to consumers for @dev and if any of them is in the
1557 * "consumer probe" state, wait for all device probes in progress to complete
1558 * and start over.
1559 *
1560 * If that's not the case, change the status of the link to "supplier unbind"
1561 * and check if the link was in the "active" state. If so, force the consumer
1562 * driver to unbind and start over (the consumer will not re-probe as we have
1563 * changed the state of the link already).
1564 *
1565 * Links without the DL_FLAG_MANAGED flag set are ignored.
1566 */
1567void device_links_unbind_consumers(struct device *dev)
1568{
1569 struct device_link *link;
1570
1571 start:
1572 device_links_write_lock();
1573
1574 list_for_each_entry(link, &dev->links.consumers, s_node) {
1575 enum device_link_state status;
1576
1577 if (!(link->flags & DL_FLAG_MANAGED) ||
1578 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1579 continue;
1580
1581 status = link->status;
1582 if (status == DL_STATE_CONSUMER_PROBE) {
1583 device_links_write_unlock();
1584
1585 wait_for_device_probe();
1586 goto start;
1587 }
1588 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1589 if (status == DL_STATE_ACTIVE) {
1590 struct device *consumer = link->consumer;
1591
1592 get_device(dev: consumer);
1593
1594 device_links_write_unlock();
1595
1596 device_release_driver_internal(dev: consumer, NULL,
1597 parent: consumer->parent);
1598 put_device(dev: consumer);
1599 goto start;
1600 }
1601 }
1602
1603 device_links_write_unlock();
1604}
1605
1606/**
1607 * device_links_purge - Delete existing links to other devices.
1608 * @dev: Target device.
1609 */
1610static void device_links_purge(struct device *dev)
1611{
1612 struct device_link *link, *ln;
1613
1614 if (dev->class == &devlink_class)
1615 return;
1616
1617 /*
1618 * Delete all of the remaining links from this device to any other
1619 * devices (either consumers or suppliers).
1620 */
1621 device_links_write_lock();
1622
1623 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1624 WARN_ON(link->status == DL_STATE_ACTIVE);
1625 __device_link_del(kref: &link->kref);
1626 }
1627
1628 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1629 WARN_ON(link->status != DL_STATE_DORMANT &&
1630 link->status != DL_STATE_NONE);
1631 __device_link_del(kref: &link->kref);
1632 }
1633
1634 device_links_write_unlock();
1635}
1636
1637#define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \
1638 DL_FLAG_SYNC_STATE_ONLY)
1639#define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \
1640 DL_FLAG_AUTOPROBE_CONSUMER)
1641#define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \
1642 DL_FLAG_PM_RUNTIME)
1643
1644static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1645static int __init fw_devlink_setup(char *arg)
1646{
1647 if (!arg)
1648 return -EINVAL;
1649
1650 if (strcmp(arg, "off") == 0) {
1651 fw_devlink_flags = 0;
1652 } else if (strcmp(arg, "permissive") == 0) {
1653 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1654 } else if (strcmp(arg, "on") == 0) {
1655 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1656 } else if (strcmp(arg, "rpm") == 0) {
1657 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1658 }
1659 return 0;
1660}
1661early_param("fw_devlink", fw_devlink_setup);
1662
1663static bool fw_devlink_strict;
1664static int __init fw_devlink_strict_setup(char *arg)
1665{
1666 return kstrtobool(s: arg, res: &fw_devlink_strict);
1667}
1668early_param("fw_devlink.strict", fw_devlink_strict_setup);
1669
1670#define FW_DEVLINK_SYNC_STATE_STRICT 0
1671#define FW_DEVLINK_SYNC_STATE_TIMEOUT 1
1672
1673#ifndef CONFIG_FW_DEVLINK_SYNC_STATE_TIMEOUT
1674static int fw_devlink_sync_state;
1675#else
1676static int fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_TIMEOUT;
1677#endif
1678
1679static int __init fw_devlink_sync_state_setup(char *arg)
1680{
1681 if (!arg)
1682 return -EINVAL;
1683
1684 if (strcmp(arg, "strict") == 0) {
1685 fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_STRICT;
1686 return 0;
1687 } else if (strcmp(arg, "timeout") == 0) {
1688 fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_TIMEOUT;
1689 return 0;
1690 }
1691 return -EINVAL;
1692}
1693early_param("fw_devlink.sync_state", fw_devlink_sync_state_setup);
1694
1695static inline u32 fw_devlink_get_flags(u8 fwlink_flags)
1696{
1697 if (fwlink_flags & FWLINK_FLAG_CYCLE)
1698 return FW_DEVLINK_FLAGS_PERMISSIVE | DL_FLAG_CYCLE;
1699
1700 return fw_devlink_flags;
1701}
1702
1703static bool fw_devlink_is_permissive(void)
1704{
1705 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE;
1706}
1707
1708bool fw_devlink_is_strict(void)
1709{
1710 return fw_devlink_strict && !fw_devlink_is_permissive();
1711}
1712
1713static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)
1714{
1715 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)
1716 return;
1717
1718 fwnode_call_int_op(fwnode, add_links);
1719 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;
1720}
1721
1722static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
1723{
1724 struct fwnode_handle *child = NULL;
1725
1726 fw_devlink_parse_fwnode(fwnode);
1727
1728 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1729 fw_devlink_parse_fwtree(fwnode: child);
1730}
1731
1732static void fw_devlink_relax_link(struct device_link *link)
1733{
1734 if (!(link->flags & DL_FLAG_INFERRED))
1735 return;
1736
1737 if (device_link_flag_is_sync_state_only(flags: link->flags))
1738 return;
1739
1740 pm_runtime_drop_link(link);
1741 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE;
1742 dev_dbg(link->consumer, "Relaxing link with %s\n",
1743 dev_name(link->supplier));
1744}
1745
1746static int fw_devlink_no_driver(struct device *dev, void *data)
1747{
1748 struct device_link *link = to_devlink(dev);
1749
1750 if (!link->supplier->can_match)
1751 fw_devlink_relax_link(link);
1752
1753 return 0;
1754}
1755
1756void fw_devlink_drivers_done(void)
1757{
1758 fw_devlink_drv_reg_done = true;
1759 device_links_write_lock();
1760 class_for_each_device(class: &devlink_class, NULL, NULL,
1761 fn: fw_devlink_no_driver);
1762 device_links_write_unlock();
1763}
1764
1765static int fw_devlink_dev_sync_state(struct device *dev, void *data)
1766{
1767 struct device_link *link = to_devlink(dev);
1768 struct device *sup = link->supplier;
1769
1770 if (!(link->flags & DL_FLAG_MANAGED) ||
1771 link->status == DL_STATE_ACTIVE || sup->state_synced ||
1772 !dev_has_sync_state(dev: sup))
1773 return 0;
1774
1775 if (fw_devlink_sync_state == FW_DEVLINK_SYNC_STATE_STRICT) {
1776 dev_warn(sup, "sync_state() pending due to %s\n",
1777 dev_name(link->consumer));
1778 return 0;
1779 }
1780
1781 if (!list_empty(head: &sup->links.defer_sync))
1782 return 0;
1783
1784 dev_warn(sup, "Timed out. Forcing sync_state()\n");
1785 sup->state_synced = true;
1786 get_device(dev: sup);
1787 list_add_tail(new: &sup->links.defer_sync, head: data);
1788
1789 return 0;
1790}
1791
1792void fw_devlink_probing_done(void)
1793{
1794 LIST_HEAD(sync_list);
1795
1796 device_links_write_lock();
1797 class_for_each_device(class: &devlink_class, NULL, data: &sync_list,
1798 fn: fw_devlink_dev_sync_state);
1799 device_links_write_unlock();
1800 device_links_flush_sync_list(list: &sync_list, NULL);
1801}
1802
1803/**
1804 * wait_for_init_devices_probe - Try to probe any device needed for init
1805 *
1806 * Some devices might need to be probed and bound successfully before the kernel
1807 * boot sequence can finish and move on to init/userspace. For example, a
1808 * network interface might need to be bound to be able to mount a NFS rootfs.
1809 *
1810 * With fw_devlink=on by default, some of these devices might be blocked from
1811 * probing because they are waiting on a optional supplier that doesn't have a
1812 * driver. While fw_devlink will eventually identify such devices and unblock
1813 * the probing automatically, it might be too late by the time it unblocks the
1814 * probing of devices. For example, the IP4 autoconfig might timeout before
1815 * fw_devlink unblocks probing of the network interface.
1816 *
1817 * This function is available to temporarily try and probe all devices that have
1818 * a driver even if some of their suppliers haven't been added or don't have
1819 * drivers.
1820 *
1821 * The drivers can then decide which of the suppliers are optional vs mandatory
1822 * and probe the device if possible. By the time this function returns, all such
1823 * "best effort" probes are guaranteed to be completed. If a device successfully
1824 * probes in this mode, we delete all fw_devlink discovered dependencies of that
1825 * device where the supplier hasn't yet probed successfully because they have to
1826 * be optional dependencies.
1827 *
1828 * Any devices that didn't successfully probe go back to being treated as if
1829 * this function was never called.
1830 *
1831 * This also means that some devices that aren't needed for init and could have
1832 * waited for their optional supplier to probe (when the supplier's module is
1833 * loaded later on) would end up probing prematurely with limited functionality.
1834 * So call this function only when boot would fail without it.
1835 */
1836void __init wait_for_init_devices_probe(void)
1837{
1838 if (!fw_devlink_flags || fw_devlink_is_permissive())
1839 return;
1840
1841 /*
1842 * Wait for all ongoing probes to finish so that the "best effort" is
1843 * only applied to devices that can't probe otherwise.
1844 */
1845 wait_for_device_probe();
1846
1847 pr_info("Trying to probe devices needed for running init ...\n");
1848 fw_devlink_best_effort = true;
1849 driver_deferred_probe_trigger();
1850
1851 /*
1852 * Wait for all "best effort" probes to finish before going back to
1853 * normal enforcement.
1854 */
1855 wait_for_device_probe();
1856 fw_devlink_best_effort = false;
1857}
1858
1859static void fw_devlink_unblock_consumers(struct device *dev)
1860{
1861 struct device_link *link;
1862
1863 if (!fw_devlink_flags || fw_devlink_is_permissive())
1864 return;
1865
1866 device_links_write_lock();
1867 list_for_each_entry(link, &dev->links.consumers, s_node)
1868 fw_devlink_relax_link(link);
1869 device_links_write_unlock();
1870}
1871
1872
1873static bool fwnode_init_without_drv(struct fwnode_handle *fwnode)
1874{
1875 struct device *dev;
1876 bool ret;
1877
1878 if (!(fwnode->flags & FWNODE_FLAG_INITIALIZED))
1879 return false;
1880
1881 dev = get_dev_from_fwnode(fwnode);
1882 ret = !dev || dev->links.status == DL_DEV_NO_DRIVER;
1883 put_device(dev);
1884
1885 return ret;
1886}
1887
1888static bool fwnode_ancestor_init_without_drv(struct fwnode_handle *fwnode)
1889{
1890 struct fwnode_handle *parent;
1891
1892 fwnode_for_each_parent_node(fwnode, parent) {
1893 if (fwnode_init_without_drv(fwnode: parent)) {
1894 fwnode_handle_put(fwnode: parent);
1895 return true;
1896 }
1897 }
1898
1899 return false;
1900}
1901
1902/**
1903 * __fw_devlink_relax_cycles - Relax and mark dependency cycles.
1904 * @con: Potential consumer device.
1905 * @sup_handle: Potential supplier's fwnode.
1906 *
1907 * Needs to be called with fwnode_lock and device link lock held.
1908 *
1909 * Check if @sup_handle or any of its ancestors or suppliers direct/indirectly
1910 * depend on @con. This function can detect multiple cyles between @sup_handle
1911 * and @con. When such dependency cycles are found, convert all device links
1912 * created solely by fw_devlink into SYNC_STATE_ONLY device links. Also, mark
1913 * all fwnode links in the cycle with FWLINK_FLAG_CYCLE so that when they are
1914 * converted into a device link in the future, they are created as
1915 * SYNC_STATE_ONLY device links. This is the equivalent of doing
1916 * fw_devlink=permissive just between the devices in the cycle. We need to do
1917 * this because, at this point, fw_devlink can't tell which of these
1918 * dependencies is not a real dependency.
1919 *
1920 * Return true if one or more cycles were found. Otherwise, return false.
1921 */
1922static bool __fw_devlink_relax_cycles(struct device *con,
1923 struct fwnode_handle *sup_handle)
1924{
1925 struct device *sup_dev = NULL, *par_dev = NULL;
1926 struct fwnode_link *link;
1927 struct device_link *dev_link;
1928 bool ret = false;
1929
1930 if (!sup_handle)
1931 return false;
1932
1933 /*
1934 * We aren't trying to find all cycles. Just a cycle between con and
1935 * sup_handle.
1936 */
1937 if (sup_handle->flags & FWNODE_FLAG_VISITED)
1938 return false;
1939
1940 sup_handle->flags |= FWNODE_FLAG_VISITED;
1941
1942 sup_dev = get_dev_from_fwnode(sup_handle);
1943
1944 /* Termination condition. */
1945 if (sup_dev == con) {
1946 ret = true;
1947 goto out;
1948 }
1949
1950 /*
1951 * If sup_dev is bound to a driver and @con hasn't started binding to a
1952 * driver, sup_dev can't be a consumer of @con. So, no need to check
1953 * further.
1954 */
1955 if (sup_dev && sup_dev->links.status == DL_DEV_DRIVER_BOUND &&
1956 con->links.status == DL_DEV_NO_DRIVER) {
1957 ret = false;
1958 goto out;
1959 }
1960
1961 list_for_each_entry(link, &sup_handle->suppliers, c_hook) {
1962 if (__fw_devlink_relax_cycles(con, sup_handle: link->supplier)) {
1963 __fwnode_link_cycle(link);
1964 ret = true;
1965 }
1966 }
1967
1968 /*
1969 * Give priority to device parent over fwnode parent to account for any
1970 * quirks in how fwnodes are converted to devices.
1971 */
1972 if (sup_dev)
1973 par_dev = get_device(dev: sup_dev->parent);
1974 else
1975 par_dev = fwnode_get_next_parent_dev(fwnode: sup_handle);
1976
1977 if (par_dev && __fw_devlink_relax_cycles(con, sup_handle: par_dev->fwnode))
1978 ret = true;
1979
1980 if (!sup_dev)
1981 goto out;
1982
1983 list_for_each_entry(dev_link, &sup_dev->links.suppliers, c_node) {
1984 /*
1985 * Ignore a SYNC_STATE_ONLY flag only if it wasn't marked as
1986 * such due to a cycle.
1987 */
1988 if (device_link_flag_is_sync_state_only(flags: dev_link->flags) &&
1989 !(dev_link->flags & DL_FLAG_CYCLE))
1990 continue;
1991
1992 if (__fw_devlink_relax_cycles(con,
1993 sup_handle: dev_link->supplier->fwnode)) {
1994 fw_devlink_relax_link(link: dev_link);
1995 dev_link->flags |= DL_FLAG_CYCLE;
1996 ret = true;
1997 }
1998 }
1999
2000out:
2001 sup_handle->flags &= ~FWNODE_FLAG_VISITED;
2002 put_device(dev: sup_dev);
2003 put_device(dev: par_dev);
2004 return ret;
2005}
2006
2007/**
2008 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
2009 * @con: consumer device for the device link
2010 * @sup_handle: fwnode handle of supplier
2011 * @link: fwnode link that's being converted to a device link
2012 *
2013 * This function will try to create a device link between the consumer device
2014 * @con and the supplier device represented by @sup_handle.
2015 *
2016 * The supplier has to be provided as a fwnode because incorrect cycles in
2017 * fwnode links can sometimes cause the supplier device to never be created.
2018 * This function detects such cases and returns an error if it cannot create a
2019 * device link from the consumer to a missing supplier.
2020 *
2021 * Returns,
2022 * 0 on successfully creating a device link
2023 * -EINVAL if the device link cannot be created as expected
2024 * -EAGAIN if the device link cannot be created right now, but it may be
2025 * possible to do that in the future
2026 */
2027static int fw_devlink_create_devlink(struct device *con,
2028 struct fwnode_handle *sup_handle,
2029 struct fwnode_link *link)
2030{
2031 struct device *sup_dev;
2032 int ret = 0;
2033 u32 flags;
2034
2035 if (con->fwnode == link->consumer)
2036 flags = fw_devlink_get_flags(fwlink_flags: link->flags);
2037 else
2038 flags = FW_DEVLINK_FLAGS_PERMISSIVE;
2039
2040 /*
2041 * In some cases, a device P might also be a supplier to its child node
2042 * C. However, this would defer the probe of C until the probe of P
2043 * completes successfully. This is perfectly fine in the device driver
2044 * model. device_add() doesn't guarantee probe completion of the device
2045 * by the time it returns.
2046 *
2047 * However, there are a few drivers that assume C will finish probing
2048 * as soon as it's added and before P finishes probing. So, we provide
2049 * a flag to let fw_devlink know not to delay the probe of C until the
2050 * probe of P completes successfully.
2051 *
2052 * When such a flag is set, we can't create device links where P is the
2053 * supplier of C as that would delay the probe of C.
2054 */
2055 if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD &&
2056 fwnode_is_ancestor_of(ancestor: sup_handle, child: con->fwnode))
2057 return -EINVAL;
2058
2059 /*
2060 * SYNC_STATE_ONLY device links don't block probing and supports cycles.
2061 * So cycle detection isn't necessary and shouldn't be done.
2062 */
2063 if (!(flags & DL_FLAG_SYNC_STATE_ONLY)) {
2064 device_links_write_lock();
2065 if (__fw_devlink_relax_cycles(con, sup_handle)) {
2066 __fwnode_link_cycle(link);
2067 flags = fw_devlink_get_flags(fwlink_flags: link->flags);
2068 dev_info(con, "Fixed dependency cycle(s) with %pfwf\n",
2069 sup_handle);
2070 }
2071 device_links_write_unlock();
2072 }
2073
2074 if (sup_handle->flags & FWNODE_FLAG_NOT_DEVICE)
2075 sup_dev = fwnode_get_next_parent_dev(fwnode: sup_handle);
2076 else
2077 sup_dev = get_dev_from_fwnode(sup_handle);
2078
2079 if (sup_dev) {
2080 /*
2081 * If it's one of those drivers that don't actually bind to
2082 * their device using driver core, then don't wait on this
2083 * supplier device indefinitely.
2084 */
2085 if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
2086 sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
2087 dev_dbg(con,
2088 "Not linking %pfwf - dev might never probe\n",
2089 sup_handle);
2090 ret = -EINVAL;
2091 goto out;
2092 }
2093
2094 if (con != sup_dev && !device_link_add(con, sup_dev, flags)) {
2095 dev_err(con, "Failed to create device link (0x%x) with %s\n",
2096 flags, dev_name(sup_dev));
2097 ret = -EINVAL;
2098 }
2099
2100 goto out;
2101 }
2102
2103 /*
2104 * Supplier or supplier's ancestor already initialized without a struct
2105 * device or being probed by a driver.
2106 */
2107 if (fwnode_init_without_drv(fwnode: sup_handle) ||
2108 fwnode_ancestor_init_without_drv(fwnode: sup_handle)) {
2109 dev_dbg(con, "Not linking %pfwf - might never become dev\n",
2110 sup_handle);
2111 return -EINVAL;
2112 }
2113
2114 ret = -EAGAIN;
2115out:
2116 put_device(dev: sup_dev);
2117 return ret;
2118}
2119
2120/**
2121 * __fw_devlink_link_to_consumers - Create device links to consumers of a device
2122 * @dev: Device that needs to be linked to its consumers
2123 *
2124 * This function looks at all the consumer fwnodes of @dev and creates device
2125 * links between the consumer device and @dev (supplier).
2126 *
2127 * If the consumer device has not been added yet, then this function creates a
2128 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device
2129 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a
2130 * sync_state() callback before the real consumer device gets to be added and
2131 * then probed.
2132 *
2133 * Once device links are created from the real consumer to @dev (supplier), the
2134 * fwnode links are deleted.
2135 */
2136static void __fw_devlink_link_to_consumers(struct device *dev)
2137{
2138 struct fwnode_handle *fwnode = dev->fwnode;
2139 struct fwnode_link *link, *tmp;
2140
2141 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
2142 struct device *con_dev;
2143 bool own_link = true;
2144 int ret;
2145
2146 con_dev = get_dev_from_fwnode(link->consumer);
2147 /*
2148 * If consumer device is not available yet, make a "proxy"
2149 * SYNC_STATE_ONLY link from the consumer's parent device to
2150 * the supplier device. This is necessary to make sure the
2151 * supplier doesn't get a sync_state() callback before the real
2152 * consumer can create a device link to the supplier.
2153 *
2154 * This proxy link step is needed to handle the case where the
2155 * consumer's parent device is added before the supplier.
2156 */
2157 if (!con_dev) {
2158 con_dev = fwnode_get_next_parent_dev(fwnode: link->consumer);
2159 /*
2160 * However, if the consumer's parent device is also the
2161 * parent of the supplier, don't create a
2162 * consumer-supplier link from the parent to its child
2163 * device. Such a dependency is impossible.
2164 */
2165 if (con_dev &&
2166 fwnode_is_ancestor_of(ancestor: con_dev->fwnode, child: fwnode)) {
2167 put_device(dev: con_dev);
2168 con_dev = NULL;
2169 } else {
2170 own_link = false;
2171 }
2172 }
2173
2174 if (!con_dev)
2175 continue;
2176
2177 ret = fw_devlink_create_devlink(con: con_dev, sup_handle: fwnode, link);
2178 put_device(dev: con_dev);
2179 if (!own_link || ret == -EAGAIN)
2180 continue;
2181
2182 __fwnode_link_del(link);
2183 }
2184}
2185
2186/**
2187 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device
2188 * @dev: The consumer device that needs to be linked to its suppliers
2189 * @fwnode: Root of the fwnode tree that is used to create device links
2190 *
2191 * This function looks at all the supplier fwnodes of fwnode tree rooted at
2192 * @fwnode and creates device links between @dev (consumer) and all the
2193 * supplier devices of the entire fwnode tree at @fwnode.
2194 *
2195 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
2196 * and the real suppliers of @dev. Once these device links are created, the
2197 * fwnode links are deleted.
2198 *
2199 * In addition, it also looks at all the suppliers of the entire fwnode tree
2200 * because some of the child devices of @dev that have not been added yet
2201 * (because @dev hasn't probed) might already have their suppliers added to
2202 * driver core. So, this function creates SYNC_STATE_ONLY device links between
2203 * @dev (consumer) and these suppliers to make sure they don't execute their
2204 * sync_state() callbacks before these child devices have a chance to create
2205 * their device links. The fwnode links that correspond to the child devices
2206 * aren't delete because they are needed later to create the device links
2207 * between the real consumer and supplier devices.
2208 */
2209static void __fw_devlink_link_to_suppliers(struct device *dev,
2210 struct fwnode_handle *fwnode)
2211{
2212 bool own_link = (dev->fwnode == fwnode);
2213 struct fwnode_link *link, *tmp;
2214 struct fwnode_handle *child = NULL;
2215
2216 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
2217 int ret;
2218 struct fwnode_handle *sup = link->supplier;
2219
2220 ret = fw_devlink_create_devlink(con: dev, sup_handle: sup, link);
2221 if (!own_link || ret == -EAGAIN)
2222 continue;
2223
2224 __fwnode_link_del(link);
2225 }
2226
2227 /*
2228 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of
2229 * all the descendants. This proxy link step is needed to handle the
2230 * case where the supplier is added before the consumer's parent device
2231 * (@dev).
2232 */
2233 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
2234 __fw_devlink_link_to_suppliers(dev, fwnode: child);
2235}
2236
2237static void fw_devlink_link_device(struct device *dev)
2238{
2239 struct fwnode_handle *fwnode = dev->fwnode;
2240
2241 if (!fw_devlink_flags)
2242 return;
2243
2244 fw_devlink_parse_fwtree(fwnode);
2245
2246 mutex_lock(&fwnode_link_lock);
2247 __fw_devlink_link_to_consumers(dev);
2248 __fw_devlink_link_to_suppliers(dev, fwnode);
2249 mutex_unlock(lock: &fwnode_link_lock);
2250}
2251
2252/* Device links support end. */
2253
2254int (*platform_notify)(struct device *dev) = NULL;
2255int (*platform_notify_remove)(struct device *dev) = NULL;
2256static struct kobject *dev_kobj;
2257
2258/* /sys/dev/char */
2259static struct kobject *sysfs_dev_char_kobj;
2260
2261/* /sys/dev/block */
2262static struct kobject *sysfs_dev_block_kobj;
2263
2264static DEFINE_MUTEX(device_hotplug_lock);
2265
2266void lock_device_hotplug(void)
2267{
2268 mutex_lock(&device_hotplug_lock);
2269}
2270
2271void unlock_device_hotplug(void)
2272{
2273 mutex_unlock(lock: &device_hotplug_lock);
2274}
2275
2276int lock_device_hotplug_sysfs(void)
2277{
2278 if (mutex_trylock(lock: &device_hotplug_lock))
2279 return 0;
2280
2281 /* Avoid busy looping (5 ms of sleep should do). */
2282 msleep(msecs: 5);
2283 return restart_syscall();
2284}
2285
2286#ifdef CONFIG_BLOCK
2287static inline int device_is_not_partition(struct device *dev)
2288{
2289 return !(dev->type == &part_type);
2290}
2291#else
2292static inline int device_is_not_partition(struct device *dev)
2293{
2294 return 1;
2295}
2296#endif
2297
2298static void device_platform_notify(struct device *dev)
2299{
2300 acpi_device_notify(dev);
2301
2302 software_node_notify(dev);
2303
2304 if (platform_notify)
2305 platform_notify(dev);
2306}
2307
2308static void device_platform_notify_remove(struct device *dev)
2309{
2310 if (platform_notify_remove)
2311 platform_notify_remove(dev);
2312
2313 software_node_notify_remove(dev);
2314
2315 acpi_device_notify_remove(dev);
2316}
2317
2318/**
2319 * dev_driver_string - Return a device's driver name, if at all possible
2320 * @dev: struct device to get the name of
2321 *
2322 * Will return the device's driver's name if it is bound to a device. If
2323 * the device is not bound to a driver, it will return the name of the bus
2324 * it is attached to. If it is not attached to a bus either, an empty
2325 * string will be returned.
2326 */
2327const char *dev_driver_string(const struct device *dev)
2328{
2329 struct device_driver *drv;
2330
2331 /* dev->driver can change to NULL underneath us because of unbinding,
2332 * so be careful about accessing it. dev->bus and dev->class should
2333 * never change once they are set, so they don't need special care.
2334 */
2335 drv = READ_ONCE(dev->driver);
2336 return drv ? drv->name : dev_bus_name(dev);
2337}
2338EXPORT_SYMBOL(dev_driver_string);
2339
2340#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
2341
2342static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
2343 char *buf)
2344{
2345 struct device_attribute *dev_attr = to_dev_attr(attr);
2346 struct device *dev = kobj_to_dev(kobj);
2347 ssize_t ret = -EIO;
2348
2349 if (dev_attr->show)
2350 ret = dev_attr->show(dev, dev_attr, buf);
2351 if (ret >= (ssize_t)PAGE_SIZE) {
2352 printk("dev_attr_show: %pS returned bad count\n",
2353 dev_attr->show);
2354 }
2355 return ret;
2356}
2357
2358static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
2359 const char *buf, size_t count)
2360{
2361 struct device_attribute *dev_attr = to_dev_attr(attr);
2362 struct device *dev = kobj_to_dev(kobj);
2363 ssize_t ret = -EIO;
2364
2365 if (dev_attr->store)
2366 ret = dev_attr->store(dev, dev_attr, buf, count);
2367 return ret;
2368}
2369
2370static const struct sysfs_ops dev_sysfs_ops = {
2371 .show = dev_attr_show,
2372 .store = dev_attr_store,
2373};
2374
2375#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
2376
2377ssize_t device_store_ulong(struct device *dev,
2378 struct device_attribute *attr,
2379 const char *buf, size_t size)
2380{
2381 struct dev_ext_attribute *ea = to_ext_attr(attr);
2382 int ret;
2383 unsigned long new;
2384
2385 ret = kstrtoul(s: buf, base: 0, res: &new);
2386 if (ret)
2387 return ret;
2388 *(unsigned long *)(ea->var) = new;
2389 /* Always return full write size even if we didn't consume all */
2390 return size;
2391}
2392EXPORT_SYMBOL_GPL(device_store_ulong);
2393
2394ssize_t device_show_ulong(struct device *dev,
2395 struct device_attribute *attr,
2396 char *buf)
2397{
2398 struct dev_ext_attribute *ea = to_ext_attr(attr);
2399 return sysfs_emit(buf, fmt: "%lx\n", *(unsigned long *)(ea->var));
2400}
2401EXPORT_SYMBOL_GPL(device_show_ulong);
2402
2403ssize_t device_store_int(struct device *dev,
2404 struct device_attribute *attr,
2405 const char *buf, size_t size)
2406{
2407 struct dev_ext_attribute *ea = to_ext_attr(attr);
2408 int ret;
2409 long new;
2410
2411 ret = kstrtol(s: buf, base: 0, res: &new);
2412 if (ret)
2413 return ret;
2414
2415 if (new > INT_MAX || new < INT_MIN)
2416 return -EINVAL;
2417 *(int *)(ea->var) = new;
2418 /* Always return full write size even if we didn't consume all */
2419 return size;
2420}
2421EXPORT_SYMBOL_GPL(device_store_int);
2422
2423ssize_t device_show_int(struct device *dev,
2424 struct device_attribute *attr,
2425 char *buf)
2426{
2427 struct dev_ext_attribute *ea = to_ext_attr(attr);
2428
2429 return sysfs_emit(buf, fmt: "%d\n", *(int *)(ea->var));
2430}
2431EXPORT_SYMBOL_GPL(device_show_int);
2432
2433ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
2434 const char *buf, size_t size)
2435{
2436 struct dev_ext_attribute *ea = to_ext_attr(attr);
2437
2438 if (kstrtobool(s: buf, res: ea->var) < 0)
2439 return -EINVAL;
2440
2441 return size;
2442}
2443EXPORT_SYMBOL_GPL(device_store_bool);
2444
2445ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
2446 char *buf)
2447{
2448 struct dev_ext_attribute *ea = to_ext_attr(attr);
2449
2450 return sysfs_emit(buf, fmt: "%d\n", *(bool *)(ea->var));
2451}
2452EXPORT_SYMBOL_GPL(device_show_bool);
2453
2454/**
2455 * device_release - free device structure.
2456 * @kobj: device's kobject.
2457 *
2458 * This is called once the reference count for the object
2459 * reaches 0. We forward the call to the device's release
2460 * method, which should handle actually freeing the structure.
2461 */
2462static void device_release(struct kobject *kobj)
2463{
2464 struct device *dev = kobj_to_dev(kobj);
2465 struct device_private *p = dev->p;
2466
2467 /*
2468 * Some platform devices are driven without driver attached
2469 * and managed resources may have been acquired. Make sure
2470 * all resources are released.
2471 *
2472 * Drivers still can add resources into device after device
2473 * is deleted but alive, so release devres here to avoid
2474 * possible memory leak.
2475 */
2476 devres_release_all(dev);
2477
2478 kfree(objp: dev->dma_range_map);
2479
2480 if (dev->release)
2481 dev->release(dev);
2482 else if (dev->type && dev->type->release)
2483 dev->type->release(dev);
2484 else if (dev->class && dev->class->dev_release)
2485 dev->class->dev_release(dev);
2486 else
2487 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",
2488 dev_name(dev));
2489 kfree(objp: p);
2490}
2491
2492static const void *device_namespace(const struct kobject *kobj)
2493{
2494 const struct device *dev = kobj_to_dev(kobj);
2495 const void *ns = NULL;
2496
2497 if (dev->class && dev->class->ns_type)
2498 ns = dev->class->namespace(dev);
2499
2500 return ns;
2501}
2502
2503static void device_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
2504{
2505 const struct device *dev = kobj_to_dev(kobj);
2506
2507 if (dev->class && dev->class->get_ownership)
2508 dev->class->get_ownership(dev, uid, gid);
2509}
2510
2511static const struct kobj_type device_ktype = {
2512 .release = device_release,
2513 .sysfs_ops = &dev_sysfs_ops,
2514 .namespace = device_namespace,
2515 .get_ownership = device_get_ownership,
2516};
2517
2518
2519static int dev_uevent_filter(const struct kobject *kobj)
2520{
2521 const struct kobj_type *ktype = get_ktype(kobj);
2522
2523 if (ktype == &device_ktype) {
2524 const struct device *dev = kobj_to_dev(kobj);
2525 if (dev->bus)
2526 return 1;
2527 if (dev->class)
2528 return 1;
2529 }
2530 return 0;
2531}
2532
2533static const char *dev_uevent_name(const struct kobject *kobj)
2534{
2535 const struct device *dev = kobj_to_dev(kobj);
2536
2537 if (dev->bus)
2538 return dev->bus->name;
2539 if (dev->class)
2540 return dev->class->name;
2541 return NULL;
2542}
2543
2544static int dev_uevent(const struct kobject *kobj, struct kobj_uevent_env *env)
2545{
2546 const struct device *dev = kobj_to_dev(kobj);
2547 int retval = 0;
2548
2549 /* add device node properties if present */
2550 if (MAJOR(dev->devt)) {
2551 const char *tmp;
2552 const char *name;
2553 umode_t mode = 0;
2554 kuid_t uid = GLOBAL_ROOT_UID;
2555 kgid_t gid = GLOBAL_ROOT_GID;
2556
2557 add_uevent_var(env, format: "MAJOR=%u", MAJOR(dev->devt));
2558 add_uevent_var(env, format: "MINOR=%u", MINOR(dev->devt));
2559 name = device_get_devnode(dev, mode: &mode, uid: &uid, gid: &gid, tmp: &tmp);
2560 if (name) {
2561 add_uevent_var(env, format: "DEVNAME=%s", name);
2562 if (mode)
2563 add_uevent_var(env, format: "DEVMODE=%#o", mode & 0777);
2564 if (!uid_eq(left: uid, GLOBAL_ROOT_UID))
2565 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
2566 if (!gid_eq(gid, GLOBAL_ROOT_GID))
2567 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
2568 kfree(tmp);
2569 }
2570 }
2571
2572 if (dev->type && dev->type->name)
2573 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
2574
2575 if (dev->driver)
2576 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
2577
2578 /* Add common DT information about the device */
2579 of_device_uevent(dev, env);
2580
2581 /* have the bus specific function add its stuff */
2582 if (dev->bus && dev->bus->uevent) {
2583 retval = dev->bus->uevent(dev, env);
2584 if (retval)
2585 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
2586 dev_name(dev), __func__, retval);
2587 }
2588
2589 /* have the class specific function add its stuff */
2590 if (dev->class && dev->class->dev_uevent) {
2591 retval = dev->class->dev_uevent(dev, env);
2592 if (retval)
2593 pr_debug("device: '%s': %s: class uevent() "
2594 "returned %d\n", dev_name(dev),
2595 __func__, retval);
2596 }
2597
2598 /* have the device type specific function add its stuff */
2599 if (dev->type && dev->type->uevent) {
2600 retval = dev->type->uevent(dev, env);
2601 if (retval)
2602 pr_debug("device: '%s': %s: dev_type uevent() "
2603 "returned %d\n", dev_name(dev),
2604 __func__, retval);
2605 }
2606
2607 return retval;
2608}
2609
2610static const struct kset_uevent_ops device_uevent_ops = {
2611 .filter = dev_uevent_filter,
2612 .name = dev_uevent_name,
2613 .uevent = dev_uevent,
2614};
2615
2616static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
2617 char *buf)
2618{
2619 struct kobject *top_kobj;
2620 struct kset *kset;
2621 struct kobj_uevent_env *env = NULL;
2622 int i;
2623 int len = 0;
2624 int retval;
2625
2626 /* search the kset, the device belongs to */
2627 top_kobj = &dev->kobj;
2628 while (!top_kobj->kset && top_kobj->parent)
2629 top_kobj = top_kobj->parent;
2630 if (!top_kobj->kset)
2631 goto out;
2632
2633 kset = top_kobj->kset;
2634 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
2635 goto out;
2636
2637 /* respect filter */
2638 if (kset->uevent_ops && kset->uevent_ops->filter)
2639 if (!kset->uevent_ops->filter(&dev->kobj))
2640 goto out;
2641
2642 env = kzalloc(size: sizeof(struct kobj_uevent_env), GFP_KERNEL);
2643 if (!env)
2644 return -ENOMEM;
2645
2646 /* let the kset specific function add its keys */
2647 retval = kset->uevent_ops->uevent(&dev->kobj, env);
2648 if (retval)
2649 goto out;
2650
2651 /* copy keys to file */
2652 for (i = 0; i < env->envp_idx; i++)
2653 len += sysfs_emit_at(buf, at: len, fmt: "%s\n", env->envp[i]);
2654out:
2655 kfree(objp: env);
2656 return len;
2657}
2658
2659static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
2660 const char *buf, size_t count)
2661{
2662 int rc;
2663
2664 rc = kobject_synth_uevent(kobj: &dev->kobj, buf, count);
2665
2666 if (rc) {
2667 dev_err(dev, "uevent: failed to send synthetic uevent: %d\n", rc);
2668 return rc;
2669 }
2670
2671 return count;
2672}
2673static DEVICE_ATTR_RW(uevent);
2674
2675static ssize_t online_show(struct device *dev, struct device_attribute *attr,
2676 char *buf)
2677{
2678 bool val;
2679
2680 device_lock(dev);
2681 val = !dev->offline;
2682 device_unlock(dev);
2683 return sysfs_emit(buf, fmt: "%u\n", val);
2684}
2685
2686static ssize_t online_store(struct device *dev, struct device_attribute *attr,
2687 const char *buf, size_t count)
2688{
2689 bool val;
2690 int ret;
2691
2692 ret = kstrtobool(s: buf, res: &val);
2693 if (ret < 0)
2694 return ret;
2695
2696 ret = lock_device_hotplug_sysfs();
2697 if (ret)
2698 return ret;
2699
2700 ret = val ? device_online(dev) : device_offline(dev);
2701 unlock_device_hotplug();
2702 return ret < 0 ? ret : count;
2703}
2704static DEVICE_ATTR_RW(online);
2705
2706static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
2707 char *buf)
2708{
2709 const char *loc;
2710
2711 switch (dev->removable) {
2712 case DEVICE_REMOVABLE:
2713 loc = "removable";
2714 break;
2715 case DEVICE_FIXED:
2716 loc = "fixed";
2717 break;
2718 default:
2719 loc = "unknown";
2720 }
2721 return sysfs_emit(buf, fmt: "%s\n", loc);
2722}
2723static DEVICE_ATTR_RO(removable);
2724
2725int device_add_groups(struct device *dev, const struct attribute_group **groups)
2726{
2727 return sysfs_create_groups(kobj: &dev->kobj, groups);
2728}
2729EXPORT_SYMBOL_GPL(device_add_groups);
2730
2731void device_remove_groups(struct device *dev,
2732 const struct attribute_group **groups)
2733{
2734 sysfs_remove_groups(kobj: &dev->kobj, groups);
2735}
2736EXPORT_SYMBOL_GPL(device_remove_groups);
2737
2738union device_attr_group_devres {
2739 const struct attribute_group *group;
2740 const struct attribute_group **groups;
2741};
2742
2743static void devm_attr_group_remove(struct device *dev, void *res)
2744{
2745 union device_attr_group_devres *devres = res;
2746 const struct attribute_group *group = devres->group;
2747
2748 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2749 sysfs_remove_group(kobj: &dev->kobj, grp: group);
2750}
2751
2752static void devm_attr_groups_remove(struct device *dev, void *res)
2753{
2754 union device_attr_group_devres *devres = res;
2755 const struct attribute_group **groups = devres->groups;
2756
2757 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2758 sysfs_remove_groups(kobj: &dev->kobj, groups);
2759}
2760
2761/**
2762 * devm_device_add_group - given a device, create a managed attribute group
2763 * @dev: The device to create the group for
2764 * @grp: The attribute group to create
2765 *
2766 * This function creates a group for the first time. It will explicitly
2767 * warn and error if any of the attribute files being created already exist.
2768 *
2769 * Returns 0 on success or error code on failure.
2770 */
2771int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2772{
2773 union device_attr_group_devres *devres;
2774 int error;
2775
2776 devres = devres_alloc(devm_attr_group_remove,
2777 sizeof(*devres), GFP_KERNEL);
2778 if (!devres)
2779 return -ENOMEM;
2780
2781 error = sysfs_create_group(kobj: &dev->kobj, grp);
2782 if (error) {
2783 devres_free(res: devres);
2784 return error;
2785 }
2786
2787 devres->group = grp;
2788 devres_add(dev, res: devres);
2789 return 0;
2790}
2791EXPORT_SYMBOL_GPL(devm_device_add_group);
2792
2793/**
2794 * devm_device_add_groups - create a bunch of managed attribute groups
2795 * @dev: The device to create the group for
2796 * @groups: The attribute groups to create, NULL terminated
2797 *
2798 * This function creates a bunch of managed attribute groups. If an error
2799 * occurs when creating a group, all previously created groups will be
2800 * removed, unwinding everything back to the original state when this
2801 * function was called. It will explicitly warn and error if any of the
2802 * attribute files being created already exist.
2803 *
2804 * Returns 0 on success or error code from sysfs_create_group on failure.
2805 */
2806int devm_device_add_groups(struct device *dev,
2807 const struct attribute_group **groups)
2808{
2809 union device_attr_group_devres *devres;
2810 int error;
2811
2812 devres = devres_alloc(devm_attr_groups_remove,
2813 sizeof(*devres), GFP_KERNEL);
2814 if (!devres)
2815 return -ENOMEM;
2816
2817 error = sysfs_create_groups(kobj: &dev->kobj, groups);
2818 if (error) {
2819 devres_free(res: devres);
2820 return error;
2821 }
2822
2823 devres->groups = groups;
2824 devres_add(dev, res: devres);
2825 return 0;
2826}
2827EXPORT_SYMBOL_GPL(devm_device_add_groups);
2828
2829static int device_add_attrs(struct device *dev)
2830{
2831 const struct class *class = dev->class;
2832 const struct device_type *type = dev->type;
2833 int error;
2834
2835 if (class) {
2836 error = device_add_groups(dev, class->dev_groups);
2837 if (error)
2838 return error;
2839 }
2840
2841 if (type) {
2842 error = device_add_groups(dev, type->groups);
2843 if (error)
2844 goto err_remove_class_groups;
2845 }
2846
2847 error = device_add_groups(dev, dev->groups);
2848 if (error)
2849 goto err_remove_type_groups;
2850
2851 if (device_supports_offline(dev) && !dev->offline_disabled) {
2852 error = device_create_file(device: dev, entry: &dev_attr_online);
2853 if (error)
2854 goto err_remove_dev_groups;
2855 }
2856
2857 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
2858 error = device_create_file(device: dev, entry: &dev_attr_waiting_for_supplier);
2859 if (error)
2860 goto err_remove_dev_online;
2861 }
2862
2863 if (dev_removable_is_valid(dev)) {
2864 error = device_create_file(device: dev, entry: &dev_attr_removable);
2865 if (error)
2866 goto err_remove_dev_waiting_for_supplier;
2867 }
2868
2869 if (dev_add_physical_location(dev)) {
2870 error = device_add_group(dev,
2871 grp: &dev_attr_physical_location_group);
2872 if (error)
2873 goto err_remove_dev_removable;
2874 }
2875
2876 return 0;
2877
2878 err_remove_dev_removable:
2879 device_remove_file(dev, attr: &dev_attr_removable);
2880 err_remove_dev_waiting_for_supplier:
2881 device_remove_file(dev, attr: &dev_attr_waiting_for_supplier);
2882 err_remove_dev_online:
2883 device_remove_file(dev, attr: &dev_attr_online);
2884 err_remove_dev_groups:
2885 device_remove_groups(dev, dev->groups);
2886 err_remove_type_groups:
2887 if (type)
2888 device_remove_groups(dev, type->groups);
2889 err_remove_class_groups:
2890 if (class)
2891 device_remove_groups(dev, class->dev_groups);
2892
2893 return error;
2894}
2895
2896static void device_remove_attrs(struct device *dev)
2897{
2898 const struct class *class = dev->class;
2899 const struct device_type *type = dev->type;
2900
2901 if (dev->physical_location) {
2902 device_remove_group(dev, grp: &dev_attr_physical_location_group);
2903 kfree(objp: dev->physical_location);
2904 }
2905
2906 device_remove_file(dev, attr: &dev_attr_removable);
2907 device_remove_file(dev, attr: &dev_attr_waiting_for_supplier);
2908 device_remove_file(dev, attr: &dev_attr_online);
2909 device_remove_groups(dev, dev->groups);
2910
2911 if (type)
2912 device_remove_groups(dev, type->groups);
2913
2914 if (class)
2915 device_remove_groups(dev, class->dev_groups);
2916}
2917
2918static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2919 char *buf)
2920{
2921 return print_dev_t(buf, dev->devt);
2922}
2923static DEVICE_ATTR_RO(dev);
2924
2925/* /sys/devices/ */
2926struct kset *devices_kset;
2927
2928/**
2929 * devices_kset_move_before - Move device in the devices_kset's list.
2930 * @deva: Device to move.
2931 * @devb: Device @deva should come before.
2932 */
2933static void devices_kset_move_before(struct device *deva, struct device *devb)
2934{
2935 if (!devices_kset)
2936 return;
2937 pr_debug("devices_kset: Moving %s before %s\n",
2938 dev_name(deva), dev_name(devb));
2939 spin_lock(lock: &devices_kset->list_lock);
2940 list_move_tail(list: &deva->kobj.entry, head: &devb->kobj.entry);
2941 spin_unlock(lock: &devices_kset->list_lock);
2942}
2943
2944/**
2945 * devices_kset_move_after - Move device in the devices_kset's list.
2946 * @deva: Device to move
2947 * @devb: Device @deva should come after.
2948 */
2949static void devices_kset_move_after(struct device *deva, struct device *devb)
2950{
2951 if (!devices_kset)
2952 return;
2953 pr_debug("devices_kset: Moving %s after %s\n",
2954 dev_name(deva), dev_name(devb));
2955 spin_lock(lock: &devices_kset->list_lock);
2956 list_move(list: &deva->kobj.entry, head: &devb->kobj.entry);
2957 spin_unlock(lock: &devices_kset->list_lock);
2958}
2959
2960/**
2961 * devices_kset_move_last - move the device to the end of devices_kset's list.
2962 * @dev: device to move
2963 */
2964void devices_kset_move_last(struct device *dev)
2965{
2966 if (!devices_kset)
2967 return;
2968 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
2969 spin_lock(lock: &devices_kset->list_lock);
2970 list_move_tail(list: &dev->kobj.entry, head: &devices_kset->list);
2971 spin_unlock(lock: &devices_kset->list_lock);
2972}
2973
2974/**
2975 * device_create_file - create sysfs attribute file for device.
2976 * @dev: device.
2977 * @attr: device attribute descriptor.
2978 */
2979int device_create_file(struct device *dev,
2980 const struct device_attribute *attr)
2981{
2982 int error = 0;
2983
2984 if (dev) {
2985 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
2986 "Attribute %s: write permission without 'store'\n",
2987 attr->attr.name);
2988 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
2989 "Attribute %s: read permission without 'show'\n",
2990 attr->attr.name);
2991 error = sysfs_create_file(kobj: &dev->kobj, attr: &attr->attr);
2992 }
2993
2994 return error;
2995}
2996EXPORT_SYMBOL_GPL(device_create_file);
2997
2998/**
2999 * device_remove_file - remove sysfs attribute file.
3000 * @dev: device.
3001 * @attr: device attribute descriptor.
3002 */
3003void device_remove_file(struct device *dev,
3004 const struct device_attribute *attr)
3005{
3006 if (dev)
3007 sysfs_remove_file(kobj: &dev->kobj, attr: &attr->attr);
3008}
3009EXPORT_SYMBOL_GPL(device_remove_file);
3010
3011/**
3012 * device_remove_file_self - remove sysfs attribute file from its own method.
3013 * @dev: device.
3014 * @attr: device attribute descriptor.
3015 *
3016 * See kernfs_remove_self() for details.
3017 */
3018bool device_remove_file_self(struct device *dev,
3019 const struct device_attribute *attr)
3020{
3021 if (dev)
3022 return sysfs_remove_file_self(kobj: &dev->kobj, attr: &attr->attr);
3023 else
3024 return false;
3025}
3026EXPORT_SYMBOL_GPL(device_remove_file_self);
3027
3028/**
3029 * device_create_bin_file - create sysfs binary attribute file for device.
3030 * @dev: device.
3031 * @attr: device binary attribute descriptor.
3032 */
3033int device_create_bin_file(struct device *dev,
3034 const struct bin_attribute *attr)
3035{
3036 int error = -EINVAL;
3037 if (dev)
3038 error = sysfs_create_bin_file(kobj: &dev->kobj, attr);
3039 return error;
3040}
3041EXPORT_SYMBOL_GPL(device_create_bin_file);
3042
3043/**
3044 * device_remove_bin_file - remove sysfs binary attribute file
3045 * @dev: device.
3046 * @attr: device binary attribute descriptor.
3047 */
3048void device_remove_bin_file(struct device *dev,
3049 const struct bin_attribute *attr)
3050{
3051 if (dev)
3052 sysfs_remove_bin_file(kobj: &dev->kobj, attr);
3053}
3054EXPORT_SYMBOL_GPL(device_remove_bin_file);
3055
3056static void klist_children_get(struct klist_node *n)
3057{
3058 struct device_private *p = to_device_private_parent(n);
3059 struct device *dev = p->device;
3060
3061 get_device(dev);
3062}
3063
3064static void klist_children_put(struct klist_node *n)
3065{
3066 struct device_private *p = to_device_private_parent(n);
3067 struct device *dev = p->device;
3068
3069 put_device(dev);
3070}
3071
3072/**
3073 * device_initialize - init device structure.
3074 * @dev: device.
3075 *
3076 * This prepares the device for use by other layers by initializing
3077 * its fields.
3078 * It is the first half of device_register(), if called by
3079 * that function, though it can also be called separately, so one
3080 * may use @dev's fields. In particular, get_device()/put_device()
3081 * may be used for reference counting of @dev after calling this
3082 * function.
3083 *
3084 * All fields in @dev must be initialized by the caller to 0, except
3085 * for those explicitly set to some other value. The simplest
3086 * approach is to use kzalloc() to allocate the structure containing
3087 * @dev.
3088 *
3089 * NOTE: Use put_device() to give up your reference instead of freeing
3090 * @dev directly once you have called this function.
3091 */
3092void device_initialize(struct device *dev)
3093{
3094 dev->kobj.kset = devices_kset;
3095 kobject_init(kobj: &dev->kobj, ktype: &device_ktype);
3096 INIT_LIST_HEAD(list: &dev->dma_pools);
3097 mutex_init(&dev->mutex);
3098 lockdep_set_novalidate_class(&dev->mutex);
3099 spin_lock_init(&dev->devres_lock);
3100 INIT_LIST_HEAD(list: &dev->devres_head);
3101 device_pm_init(dev);
3102 set_dev_node(dev, NUMA_NO_NODE);
3103 INIT_LIST_HEAD(list: &dev->links.consumers);
3104 INIT_LIST_HEAD(list: &dev->links.suppliers);
3105 INIT_LIST_HEAD(list: &dev->links.defer_sync);
3106 dev->links.status = DL_DEV_NO_DRIVER;
3107#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
3108 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
3109 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
3110 dev->dma_coherent = dma_default_coherent;
3111#endif
3112 swiotlb_dev_init(dev);
3113}
3114EXPORT_SYMBOL_GPL(device_initialize);
3115
3116struct kobject *virtual_device_parent(struct device *dev)
3117{
3118 static struct kobject *virtual_dir = NULL;
3119
3120 if (!virtual_dir)
3121 virtual_dir = kobject_create_and_add(name: "virtual",
3122 parent: &devices_kset->kobj);
3123
3124 return virtual_dir;
3125}
3126
3127struct class_dir {
3128 struct kobject kobj;
3129 const struct class *class;
3130};
3131
3132#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
3133
3134static void class_dir_release(struct kobject *kobj)
3135{
3136 struct class_dir *dir = to_class_dir(kobj);
3137 kfree(objp: dir);
3138}
3139
3140static const
3141struct kobj_ns_type_operations *class_dir_child_ns_type(const struct kobject *kobj)
3142{
3143 const struct class_dir *dir = to_class_dir(kobj);
3144 return dir->class->ns_type;
3145}
3146
3147static const struct kobj_type class_dir_ktype = {
3148 .release = class_dir_release,
3149 .sysfs_ops = &kobj_sysfs_ops,
3150 .child_ns_type = class_dir_child_ns_type
3151};
3152
3153static struct kobject *class_dir_create_and_add(struct subsys_private *sp,
3154 struct kobject *parent_kobj)
3155{
3156 struct class_dir *dir;
3157 int retval;
3158
3159 dir = kzalloc(size: sizeof(*dir), GFP_KERNEL);
3160 if (!dir)
3161 return ERR_PTR(error: -ENOMEM);
3162
3163 dir->class = sp->class;
3164 kobject_init(kobj: &dir->kobj, ktype: &class_dir_ktype);
3165
3166 dir->kobj.kset = &sp->glue_dirs;
3167
3168 retval = kobject_add(kobj: &dir->kobj, parent: parent_kobj, fmt: "%s", sp->class->name);
3169 if (retval < 0) {
3170 kobject_put(kobj: &dir->kobj);
3171 return ERR_PTR(error: retval);
3172 }
3173 return &dir->kobj;
3174}
3175
3176static DEFINE_MUTEX(gdp_mutex);
3177
3178static struct kobject *get_device_parent(struct device *dev,
3179 struct device *parent)
3180{
3181 struct subsys_private *sp = class_to_subsys(class: dev->class);
3182 struct kobject *kobj = NULL;
3183
3184 if (sp) {
3185 struct kobject *parent_kobj;
3186 struct kobject *k;
3187
3188 /*
3189 * If we have no parent, we live in "virtual".
3190 * Class-devices with a non class-device as parent, live
3191 * in a "glue" directory to prevent namespace collisions.
3192 */
3193 if (parent == NULL)
3194 parent_kobj = virtual_device_parent(dev);
3195 else if (parent->class && !dev->class->ns_type) {
3196 subsys_put(sp);
3197 return &parent->kobj;
3198 } else {
3199 parent_kobj = &parent->kobj;
3200 }
3201
3202 mutex_lock(&gdp_mutex);
3203
3204 /* find our class-directory at the parent and reference it */
3205 spin_lock(lock: &sp->glue_dirs.list_lock);
3206 list_for_each_entry(k, &sp->glue_dirs.list, entry)
3207 if (k->parent == parent_kobj) {
3208 kobj = kobject_get(kobj: k);
3209 break;
3210 }
3211 spin_unlock(lock: &sp->glue_dirs.list_lock);
3212 if (kobj) {
3213 mutex_unlock(lock: &gdp_mutex);
3214 subsys_put(sp);
3215 return kobj;
3216 }
3217
3218 /* or create a new class-directory at the parent device */
3219 k = class_dir_create_and_add(sp, parent_kobj);
3220 /* do not emit an uevent for this simple "glue" directory */
3221 mutex_unlock(lock: &gdp_mutex);
3222 subsys_put(sp);
3223 return k;
3224 }
3225
3226 /* subsystems can specify a default root directory for their devices */
3227 if (!parent && dev->bus) {
3228 struct device *dev_root = bus_get_dev_root(bus: dev->bus);
3229
3230 if (dev_root) {
3231 kobj = &dev_root->kobj;
3232 put_device(dev: dev_root);
3233 return kobj;
3234 }
3235 }
3236
3237 if (parent)
3238 return &parent->kobj;
3239 return NULL;
3240}
3241
3242static inline bool live_in_glue_dir(struct kobject *kobj,
3243 struct device *dev)
3244{
3245 struct subsys_private *sp;
3246 bool retval;
3247
3248 if (!kobj || !dev->class)
3249 return false;
3250
3251 sp = class_to_subsys(class: dev->class);
3252 if (!sp)
3253 return false;
3254
3255 if (kobj->kset == &sp->glue_dirs)
3256 retval = true;
3257 else
3258 retval = false;
3259
3260 subsys_put(sp);
3261 return retval;
3262}
3263
3264static inline struct kobject *get_glue_dir(struct device *dev)
3265{
3266 return dev->kobj.parent;
3267}
3268
3269/**
3270 * kobject_has_children - Returns whether a kobject has children.
3271 * @kobj: the object to test
3272 *
3273 * This will return whether a kobject has other kobjects as children.
3274 *
3275 * It does NOT account for the presence of attribute files, only sub
3276 * directories. It also assumes there is no concurrent addition or
3277 * removal of such children, and thus relies on external locking.
3278 */
3279static inline bool kobject_has_children(struct kobject *kobj)
3280{
3281 WARN_ON_ONCE(kref_read(&kobj->kref) == 0);
3282
3283 return kobj->sd && kobj->sd->dir.subdirs;
3284}
3285
3286/*
3287 * make sure cleaning up dir as the last step, we need to make
3288 * sure .release handler of kobject is run with holding the
3289 * global lock
3290 */
3291static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
3292{
3293 unsigned int ref;
3294
3295 /* see if we live in a "glue" directory */
3296 if (!live_in_glue_dir(kobj: glue_dir, dev))
3297 return;
3298
3299 mutex_lock(&gdp_mutex);
3300 /**
3301 * There is a race condition between removing glue directory
3302 * and adding a new device under the glue directory.
3303 *
3304 * CPU1: CPU2:
3305 *
3306 * device_add()
3307 * get_device_parent()
3308 * class_dir_create_and_add()
3309 * kobject_add_internal()
3310 * create_dir() // create glue_dir
3311 *
3312 * device_add()
3313 * get_device_parent()
3314 * kobject_get() // get glue_dir
3315 *
3316 * device_del()
3317 * cleanup_glue_dir()
3318 * kobject_del(glue_dir)
3319 *
3320 * kobject_add()
3321 * kobject_add_internal()
3322 * create_dir() // in glue_dir
3323 * sysfs_create_dir_ns()
3324 * kernfs_create_dir_ns(sd)
3325 *
3326 * sysfs_remove_dir() // glue_dir->sd=NULL
3327 * sysfs_put() // free glue_dir->sd
3328 *
3329 * // sd is freed
3330 * kernfs_new_node(sd)
3331 * kernfs_get(glue_dir)
3332 * kernfs_add_one()
3333 * kernfs_put()
3334 *
3335 * Before CPU1 remove last child device under glue dir, if CPU2 add
3336 * a new device under glue dir, the glue_dir kobject reference count
3337 * will be increase to 2 in kobject_get(k). And CPU2 has been called
3338 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
3339 * and sysfs_put(). This result in glue_dir->sd is freed.
3340 *
3341 * Then the CPU2 will see a stale "empty" but still potentially used
3342 * glue dir around in kernfs_new_node().
3343 *
3344 * In order to avoid this happening, we also should make sure that
3345 * kernfs_node for glue_dir is released in CPU1 only when refcount
3346 * for glue_dir kobj is 1.
3347 */
3348 ref = kref_read(kref: &glue_dir->kref);
3349 if (!kobject_has_children(kobj: glue_dir) && !--ref)
3350 kobject_del(kobj: glue_dir);
3351 kobject_put(kobj: glue_dir);
3352 mutex_unlock(lock: &gdp_mutex);
3353}
3354
3355static int device_add_class_symlinks(struct device *dev)
3356{
3357 struct device_node *of_node = dev_of_node(dev);
3358 struct subsys_private *sp;
3359 int error;
3360
3361 if (of_node) {
3362 error = sysfs_create_link(kobj: &dev->kobj, of_node_kobj(of_node), name: "of_node");
3363 if (error)
3364 dev_warn(dev, "Error %d creating of_node link\n",error);
3365 /* An error here doesn't warrant bringing down the device */
3366 }
3367
3368 sp = class_to_subsys(class: dev->class);
3369 if (!sp)
3370 return 0;
3371
3372 error = sysfs_create_link(kobj: &dev->kobj, target: &sp->subsys.kobj, name: "subsystem");
3373 if (error)
3374 goto out_devnode;
3375
3376 if (dev->parent && device_is_not_partition(dev)) {
3377 error = sysfs_create_link(kobj: &dev->kobj, target: &dev->parent->kobj,
3378 name: "device");
3379 if (error)
3380 goto out_subsys;
3381 }
3382
3383 /* link in the class directory pointing to the device */
3384 error = sysfs_create_link(kobj: &sp->subsys.kobj, target: &dev->kobj, name: dev_name(dev));
3385 if (error)
3386 goto out_device;
3387 goto exit;
3388
3389out_device:
3390 sysfs_remove_link(kobj: &dev->kobj, name: "device");
3391out_subsys:
3392 sysfs_remove_link(kobj: &dev->kobj, name: "subsystem");
3393out_devnode:
3394 sysfs_remove_link(kobj: &dev->kobj, name: "of_node");
3395exit:
3396 subsys_put(sp);
3397 return error;
3398}
3399
3400static void device_remove_class_symlinks(struct device *dev)
3401{
3402 struct subsys_private *sp = class_to_subsys(class: dev->class);
3403
3404 if (dev_of_node(dev))
3405 sysfs_remove_link(kobj: &dev->kobj, name: "of_node");
3406
3407 if (!sp)
3408 return;
3409
3410 if (dev->parent && device_is_not_partition(dev))
3411 sysfs_remove_link(kobj: &dev->kobj, name: "device");
3412 sysfs_remove_link(kobj: &dev->kobj, name: "subsystem");
3413 sysfs_delete_link(dir: &sp->subsys.kobj, targ: &dev->kobj, name: dev_name(dev));
3414 subsys_put(sp);
3415}
3416
3417/**
3418 * dev_set_name - set a device name
3419 * @dev: device
3420 * @fmt: format string for the device's name
3421 */
3422int dev_set_name(struct device *dev, const char *fmt, ...)
3423{
3424 va_list vargs;
3425 int err;
3426
3427 va_start(vargs, fmt);
3428 err = kobject_set_name_vargs(kobj: &dev->kobj, fmt, vargs);
3429 va_end(vargs);
3430 return err;
3431}
3432EXPORT_SYMBOL_GPL(dev_set_name);
3433
3434/* select a /sys/dev/ directory for the device */
3435static struct kobject *device_to_dev_kobj(struct device *dev)
3436{
3437 if (is_blockdev(dev))
3438 return sysfs_dev_block_kobj;
3439 else
3440 return sysfs_dev_char_kobj;
3441}
3442
3443static int device_create_sys_dev_entry(struct device *dev)
3444{
3445 struct kobject *kobj = device_to_dev_kobj(dev);
3446 int error = 0;
3447 char devt_str[15];
3448
3449 if (kobj) {
3450 format_dev_t(devt_str, dev->devt);
3451 error = sysfs_create_link(kobj, target: &dev->kobj, name: devt_str);
3452 }
3453
3454 return error;
3455}
3456
3457static void device_remove_sys_dev_entry(struct device *dev)
3458{
3459 struct kobject *kobj = device_to_dev_kobj(dev);
3460 char devt_str[15];
3461
3462 if (kobj) {
3463 format_dev_t(devt_str, dev->devt);
3464 sysfs_remove_link(kobj, name: devt_str);
3465 }
3466}
3467
3468static int device_private_init(struct device *dev)
3469{
3470 dev->p = kzalloc(size: sizeof(*dev->p), GFP_KERNEL);
3471 if (!dev->p)
3472 return -ENOMEM;
3473 dev->p->device = dev;
3474 klist_init(k: &dev->p->klist_children, get: klist_children_get,
3475 put: klist_children_put);
3476 INIT_LIST_HEAD(list: &dev->p->deferred_probe);
3477 return 0;
3478}
3479
3480/**
3481 * device_add - add device to device hierarchy.
3482 * @dev: device.
3483 *
3484 * This is part 2 of device_register(), though may be called
3485 * separately _iff_ device_initialize() has been called separately.
3486 *
3487 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
3488 * to the global and sibling lists for the device, then
3489 * adds it to the other relevant subsystems of the driver model.
3490 *
3491 * Do not call this routine or device_register() more than once for
3492 * any device structure. The driver model core is not designed to work
3493 * with devices that get unregistered and then spring back to life.
3494 * (Among other things, it's very hard to guarantee that all references
3495 * to the previous incarnation of @dev have been dropped.) Allocate
3496 * and register a fresh new struct device instead.
3497 *
3498 * NOTE: _Never_ directly free @dev after calling this function, even
3499 * if it returned an error! Always use put_device() to give up your
3500 * reference instead.
3501 *
3502 * Rule of thumb is: if device_add() succeeds, you should call
3503 * device_del() when you want to get rid of it. If device_add() has
3504 * *not* succeeded, use *only* put_device() to drop the reference
3505 * count.
3506 */
3507int device_add(struct device *dev)
3508{
3509 struct subsys_private *sp;
3510 struct device *parent;
3511 struct kobject *kobj;
3512 struct class_interface *class_intf;
3513 int error = -EINVAL;
3514 struct kobject *glue_dir = NULL;
3515
3516 dev = get_device(dev);
3517 if (!dev)
3518 goto done;
3519
3520 if (!dev->p) {
3521 error = device_private_init(dev);
3522 if (error)
3523 goto done;
3524 }
3525
3526 /*
3527 * for statically allocated devices, which should all be converted
3528 * some day, we need to initialize the name. We prevent reading back
3529 * the name, and force the use of dev_name()
3530 */
3531 if (dev->init_name) {
3532 error = dev_set_name(dev, "%s", dev->init_name);
3533 dev->init_name = NULL;
3534 }
3535
3536 if (dev_name(dev))
3537 error = 0;
3538 /* subsystems can specify simple device enumeration */
3539 else if (dev->bus && dev->bus->dev_name)
3540 error = dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
3541 else
3542 error = -EINVAL;
3543 if (error)
3544 goto name_error;
3545
3546 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3547
3548 parent = get_device(dev: dev->parent);
3549 kobj = get_device_parent(dev, parent);
3550 if (IS_ERR(ptr: kobj)) {
3551 error = PTR_ERR(ptr: kobj);
3552 goto parent_error;
3553 }
3554 if (kobj)
3555 dev->kobj.parent = kobj;
3556
3557 /* use parent numa_node */
3558 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
3559 set_dev_node(dev, node: dev_to_node(dev: parent));
3560
3561 /* first, register with generic layer. */
3562 /* we require the name to be set before, and pass NULL */
3563 error = kobject_add(kobj: &dev->kobj, parent: dev->kobj.parent, NULL);
3564 if (error) {
3565 glue_dir = kobj;
3566 goto Error;
3567 }
3568
3569 /* notify platform of device entry */
3570 device_platform_notify(dev);
3571
3572 error = device_create_file(dev, &dev_attr_uevent);
3573 if (error)
3574 goto attrError;
3575
3576 error = device_add_class_symlinks(dev);
3577 if (error)
3578 goto SymlinkError;
3579 error = device_add_attrs(dev);
3580 if (error)
3581 goto AttrsError;
3582 error = bus_add_device(dev);
3583 if (error)
3584 goto BusError;
3585 error = dpm_sysfs_add(dev);
3586 if (error)
3587 goto DPMError;
3588 device_pm_add(dev);
3589
3590 if (MAJOR(dev->devt)) {
3591 error = device_create_file(dev, &dev_attr_dev);
3592 if (error)
3593 goto DevAttrError;
3594
3595 error = device_create_sys_dev_entry(dev);
3596 if (error)
3597 goto SysEntryError;
3598
3599 devtmpfs_create_node(dev);
3600 }
3601
3602 /* Notify clients of device addition. This call must come
3603 * after dpm_sysfs_add() and before kobject_uevent().
3604 */
3605 bus_notify(dev, value: BUS_NOTIFY_ADD_DEVICE);
3606 kobject_uevent(kobj: &dev->kobj, action: KOBJ_ADD);
3607
3608 /*
3609 * Check if any of the other devices (consumers) have been waiting for
3610 * this device (supplier) to be added so that they can create a device
3611 * link to it.
3612 *
3613 * This needs to happen after device_pm_add() because device_link_add()
3614 * requires the supplier be registered before it's called.
3615 *
3616 * But this also needs to happen before bus_probe_device() to make sure
3617 * waiting consumers can link to it before the driver is bound to the
3618 * device and the driver sync_state callback is called for this device.
3619 */
3620 if (dev->fwnode && !dev->fwnode->dev) {
3621 dev->fwnode->dev = dev;
3622 fw_devlink_link_device(dev);
3623 }
3624
3625 bus_probe_device(dev);
3626
3627 /*
3628 * If all driver registration is done and a newly added device doesn't
3629 * match with any driver, don't block its consumers from probing in
3630 * case the consumer device is able to operate without this supplier.
3631 */
3632 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
3633 fw_devlink_unblock_consumers(dev);
3634
3635 if (parent)
3636 klist_add_tail(n: &dev->p->knode_parent,
3637 k: &parent->p->klist_children);
3638
3639 sp = class_to_subsys(class: dev->class);
3640 if (sp) {
3641 mutex_lock(&sp->mutex);
3642 /* tie the class to the device */
3643 klist_add_tail(n: &dev->p->knode_class, k: &sp->klist_devices);
3644
3645 /* notify any interfaces that the device is here */
3646 list_for_each_entry(class_intf, &sp->interfaces, node)
3647 if (class_intf->add_dev)
3648 class_intf->add_dev(dev);
3649 mutex_unlock(lock: &sp->mutex);
3650 subsys_put(sp);
3651 }
3652done:
3653 put_device(dev);
3654 return error;
3655 SysEntryError:
3656 if (MAJOR(dev->devt))
3657 device_remove_file(dev, &dev_attr_dev);
3658 DevAttrError:
3659 device_pm_remove(dev);
3660 dpm_sysfs_remove(dev);
3661 DPMError:
3662 dev->driver = NULL;
3663 bus_remove_device(dev);
3664 BusError:
3665 device_remove_attrs(dev);
3666 AttrsError:
3667 device_remove_class_symlinks(dev);
3668 SymlinkError:
3669 device_remove_file(dev, &dev_attr_uevent);
3670 attrError:
3671 device_platform_notify_remove(dev);
3672 kobject_uevent(kobj: &dev->kobj, action: KOBJ_REMOVE);
3673 glue_dir = get_glue_dir(dev);
3674 kobject_del(kobj: &dev->kobj);
3675 Error:
3676 cleanup_glue_dir(dev, glue_dir);
3677parent_error:
3678 put_device(dev: parent);
3679name_error:
3680 kfree(objp: dev->p);
3681 dev->p = NULL;
3682 goto done;
3683}
3684EXPORT_SYMBOL_GPL(device_add);
3685
3686/**
3687 * device_register - register a device with the system.
3688 * @dev: pointer to the device structure
3689 *
3690 * This happens in two clean steps - initialize the device
3691 * and add it to the system. The two steps can be called
3692 * separately, but this is the easiest and most common.
3693 * I.e. you should only call the two helpers separately if
3694 * have a clearly defined need to use and refcount the device
3695 * before it is added to the hierarchy.
3696 *
3697 * For more information, see the kerneldoc for device_initialize()
3698 * and device_add().
3699 *
3700 * NOTE: _Never_ directly free @dev after calling this function, even
3701 * if it returned an error! Always use put_device() to give up the
3702 * reference initialized in this function instead.
3703 */
3704int device_register(struct device *dev)
3705{
3706 device_initialize(dev);
3707 return device_add(dev);
3708}
3709EXPORT_SYMBOL_GPL(device_register);
3710
3711/**
3712 * get_device - increment reference count for device.
3713 * @dev: device.
3714 *
3715 * This simply forwards the call to kobject_get(), though
3716 * we do take care to provide for the case that we get a NULL
3717 * pointer passed in.
3718 */
3719struct device *get_device(struct device *dev)
3720{
3721 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3722}
3723EXPORT_SYMBOL_GPL(get_device);
3724
3725/**
3726 * put_device - decrement reference count.
3727 * @dev: device in question.
3728 */
3729void put_device(struct device *dev)
3730{
3731 /* might_sleep(); */
3732 if (dev)
3733 kobject_put(kobj: &dev->kobj);
3734}
3735EXPORT_SYMBOL_GPL(put_device);
3736
3737bool kill_device(struct device *dev)
3738{
3739 /*
3740 * Require the device lock and set the "dead" flag to guarantee that
3741 * the update behavior is consistent with the other bitfields near
3742 * it and that we cannot have an asynchronous probe routine trying
3743 * to run while we are tearing out the bus/class/sysfs from
3744 * underneath the device.
3745 */
3746 device_lock_assert(dev);
3747
3748 if (dev->p->dead)
3749 return false;
3750 dev->p->dead = true;
3751 return true;
3752}
3753EXPORT_SYMBOL_GPL(kill_device);
3754
3755/**
3756 * device_del - delete device from system.
3757 * @dev: device.
3758 *
3759 * This is the first part of the device unregistration
3760 * sequence. This removes the device from the lists we control
3761 * from here, has it removed from the other driver model
3762 * subsystems it was added to in device_add(), and removes it
3763 * from the kobject hierarchy.
3764 *
3765 * NOTE: this should be called manually _iff_ device_add() was
3766 * also called manually.
3767 */
3768void device_del(struct device *dev)
3769{
3770 struct subsys_private *sp;
3771 struct device *parent = dev->parent;
3772 struct kobject *glue_dir = NULL;
3773 struct class_interface *class_intf;
3774 unsigned int noio_flag;
3775
3776 device_lock(dev);
3777 kill_device(dev);
3778 device_unlock(dev);
3779
3780 if (dev->fwnode && dev->fwnode->dev == dev)
3781 dev->fwnode->dev = NULL;
3782
3783 /* Notify clients of device removal. This call must come
3784 * before dpm_sysfs_remove().
3785 */
3786 noio_flag = memalloc_noio_save();
3787 bus_notify(dev, value: BUS_NOTIFY_DEL_DEVICE);
3788
3789 dpm_sysfs_remove(dev);
3790 if (parent)
3791 klist_del(n: &dev->p->knode_parent);
3792 if (MAJOR(dev->devt)) {
3793 devtmpfs_delete_node(dev);
3794 device_remove_sys_dev_entry(dev);
3795 device_remove_file(dev, &dev_attr_dev);
3796 }
3797
3798 sp = class_to_subsys(class: dev->class);
3799 if (sp) {
3800 device_remove_class_symlinks(dev);
3801
3802 mutex_lock(&sp->mutex);
3803 /* notify any interfaces that the device is now gone */
3804 list_for_each_entry(class_intf, &sp->interfaces, node)
3805 if (class_intf->remove_dev)
3806 class_intf->remove_dev(dev);
3807 /* remove the device from the class list */
3808 klist_del(n: &dev->p->knode_class);
3809 mutex_unlock(lock: &sp->mutex);
3810 subsys_put(sp);
3811 }
3812 device_remove_file(dev, &dev_attr_uevent);
3813 device_remove_attrs(dev);
3814 bus_remove_device(dev);
3815 device_pm_remove(dev);
3816 driver_deferred_probe_del(dev);
3817 device_platform_notify_remove(dev);
3818 device_links_purge(dev);
3819
3820 /*
3821 * If a device does not have a driver attached, we need to clean
3822 * up any managed resources. We do this in device_release(), but
3823 * it's never called (and we leak the device) if a managed
3824 * resource holds a reference to the device. So release all
3825 * managed resources here, like we do in driver_detach(). We
3826 * still need to do so again in device_release() in case someone
3827 * adds a new resource after this point, though.
3828 */
3829 devres_release_all(dev);
3830
3831 bus_notify(dev, value: BUS_NOTIFY_REMOVED_DEVICE);
3832 kobject_uevent(kobj: &dev->kobj, action: KOBJ_REMOVE);
3833 glue_dir = get_glue_dir(dev);
3834 kobject_del(kobj: &dev->kobj);
3835 cleanup_glue_dir(dev, glue_dir);
3836 memalloc_noio_restore(flags: noio_flag);
3837 put_device(parent);
3838}
3839EXPORT_SYMBOL_GPL(device_del);
3840
3841/**
3842 * device_unregister - unregister device from system.
3843 * @dev: device going away.
3844 *
3845 * We do this in two parts, like we do device_register(). First,
3846 * we remove it from all the subsystems with device_del(), then
3847 * we decrement the reference count via put_device(). If that
3848 * is the final reference count, the device will be cleaned up
3849 * via device_release() above. Otherwise, the structure will
3850 * stick around until the final reference to the device is dropped.
3851 */
3852void device_unregister(struct device *dev)
3853{
3854 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3855 device_del(dev);
3856 put_device(dev);
3857}
3858EXPORT_SYMBOL_GPL(device_unregister);
3859
3860static struct device *prev_device(struct klist_iter *i)
3861{
3862 struct klist_node *n = klist_prev(i);
3863 struct device *dev = NULL;
3864 struct device_private *p;
3865
3866 if (n) {
3867 p = to_device_private_parent(n);
3868 dev = p->device;
3869 }
3870 return dev;
3871}
3872
3873static struct device *next_device(struct klist_iter *i)
3874{
3875 struct klist_node *n = klist_next(i);
3876 struct device *dev = NULL;
3877 struct device_private *p;
3878
3879 if (n) {
3880 p = to_device_private_parent(n);
3881 dev = p->device;
3882 }
3883 return dev;
3884}
3885
3886/**
3887 * device_get_devnode - path of device node file
3888 * @dev: device
3889 * @mode: returned file access mode
3890 * @uid: returned file owner
3891 * @gid: returned file group
3892 * @tmp: possibly allocated string
3893 *
3894 * Return the relative path of a possible device node.
3895 * Non-default names may need to allocate a memory to compose
3896 * a name. This memory is returned in tmp and needs to be
3897 * freed by the caller.
3898 */
3899const char *device_get_devnode(const struct device *dev,
3900 umode_t *mode, kuid_t *uid, kgid_t *gid,
3901 const char **tmp)
3902{
3903 char *s;
3904
3905 *tmp = NULL;
3906
3907 /* the device type may provide a specific name */
3908 if (dev->type && dev->type->devnode)
3909 *tmp = dev->type->devnode(dev, mode, uid, gid);
3910 if (*tmp)
3911 return *tmp;
3912
3913 /* the class may provide a specific name */
3914 if (dev->class && dev->class->devnode)
3915 *tmp = dev->class->devnode(dev, mode);
3916 if (*tmp)
3917 return *tmp;
3918
3919 /* return name without allocation, tmp == NULL */
3920 if (strchr(dev_name(dev), '!') == NULL)
3921 return dev_name(dev);
3922
3923 /* replace '!' in the name with '/' */
3924 s = kstrdup_and_replace(src: dev_name(dev), old: '!', new: '/', GFP_KERNEL);
3925 if (!s)
3926 return NULL;
3927 return *tmp = s;
3928}
3929
3930/**
3931 * device_for_each_child - device child iterator.
3932 * @parent: parent struct device.
3933 * @fn: function to be called for each device.
3934 * @data: data for the callback.
3935 *
3936 * Iterate over @parent's child devices, and call @fn for each,
3937 * passing it @data.
3938 *
3939 * We check the return of @fn each time. If it returns anything
3940 * other than 0, we break out and return that value.
3941 */
3942int device_for_each_child(struct device *parent, void *data,
3943 int (*fn)(struct device *dev, void *data))
3944{
3945 struct klist_iter i;
3946 struct device *child;
3947 int error = 0;
3948
3949 if (!parent->p)
3950 return 0;
3951
3952 klist_iter_init(k: &parent->p->klist_children, i: &i);
3953 while (!error && (child = next_device(i: &i)))
3954 error = fn(child, data);
3955 klist_iter_exit(i: &i);
3956 return error;
3957}
3958EXPORT_SYMBOL_GPL(device_for_each_child);
3959
3960/**
3961 * device_for_each_child_reverse - device child iterator in reversed order.
3962 * @parent: parent struct device.
3963 * @fn: function to be called for each device.
3964 * @data: data for the callback.
3965 *
3966 * Iterate over @parent's child devices, and call @fn for each,
3967 * passing it @data.
3968 *
3969 * We check the return of @fn each time. If it returns anything
3970 * other than 0, we break out and return that value.
3971 */
3972int device_for_each_child_reverse(struct device *parent, void *data,
3973 int (*fn)(struct device *dev, void *data))
3974{
3975 struct klist_iter i;
3976 struct device *child;
3977 int error = 0;
3978
3979 if (!parent->p)
3980 return 0;
3981
3982 klist_iter_init(k: &parent->p->klist_children, i: &i);
3983 while ((child = prev_device(i: &i)) && !error)
3984 error = fn(child, data);
3985 klist_iter_exit(i: &i);
3986 return error;
3987}
3988EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
3989
3990/**
3991 * device_find_child - device iterator for locating a particular device.
3992 * @parent: parent struct device
3993 * @match: Callback function to check device
3994 * @data: Data to pass to match function
3995 *
3996 * This is similar to the device_for_each_child() function above, but it
3997 * returns a reference to a device that is 'found' for later use, as
3998 * determined by the @match callback.
3999 *
4000 * The callback should return 0 if the device doesn't match and non-zero
4001 * if it does. If the callback returns non-zero and a reference to the
4002 * current device can be obtained, this function will return to the caller
4003 * and not iterate over any more devices.
4004 *
4005 * NOTE: you will need to drop the reference with put_device() after use.
4006 */
4007struct device *device_find_child(struct device *parent, void *data,
4008 int (*match)(struct device *dev, void *data))
4009{
4010 struct klist_iter i;
4011 struct device *child;
4012
4013 if (!parent)
4014 return NULL;
4015
4016 klist_iter_init(k: &parent->p->klist_children, i: &i);
4017 while ((child = next_device(i: &i)))
4018 if (match(child, data) && get_device(child))
4019 break;
4020 klist_iter_exit(i: &i);
4021 return child;
4022}
4023EXPORT_SYMBOL_GPL(device_find_child);
4024
4025/**
4026 * device_find_child_by_name - device iterator for locating a child device.
4027 * @parent: parent struct device
4028 * @name: name of the child device
4029 *
4030 * This is similar to the device_find_child() function above, but it
4031 * returns a reference to a device that has the name @name.
4032 *
4033 * NOTE: you will need to drop the reference with put_device() after use.
4034 */
4035struct device *device_find_child_by_name(struct device *parent,
4036 const char *name)
4037{
4038 struct klist_iter i;
4039 struct device *child;
4040
4041 if (!parent)
4042 return NULL;
4043
4044 klist_iter_init(k: &parent->p->klist_children, i: &i);
4045 while ((child = next_device(i: &i)))
4046 if (sysfs_streq(s1: dev_name(dev: child), s2: name) && get_device(child))
4047 break;
4048 klist_iter_exit(i: &i);
4049 return child;
4050}
4051EXPORT_SYMBOL_GPL(device_find_child_by_name);
4052
4053static int match_any(struct device *dev, void *unused)
4054{
4055 return 1;
4056}
4057
4058/**
4059 * device_find_any_child - device iterator for locating a child device, if any.
4060 * @parent: parent struct device
4061 *
4062 * This is similar to the device_find_child() function above, but it
4063 * returns a reference to a child device, if any.
4064 *
4065 * NOTE: you will need to drop the reference with put_device() after use.
4066 */
4067struct device *device_find_any_child(struct device *parent)
4068{
4069 return device_find_child(parent, NULL, match_any);
4070}
4071EXPORT_SYMBOL_GPL(device_find_any_child);
4072
4073int __init devices_init(void)
4074{
4075 devices_kset = kset_create_and_add(name: "devices", u: &device_uevent_ops, NULL);
4076 if (!devices_kset)
4077 return -ENOMEM;
4078 dev_kobj = kobject_create_and_add(name: "dev", NULL);
4079 if (!dev_kobj)
4080 goto dev_kobj_err;
4081 sysfs_dev_block_kobj = kobject_create_and_add(name: "block", parent: dev_kobj);
4082 if (!sysfs_dev_block_kobj)
4083 goto block_kobj_err;
4084 sysfs_dev_char_kobj = kobject_create_and_add(name: "char", parent: dev_kobj);
4085 if (!sysfs_dev_char_kobj)
4086 goto char_kobj_err;
4087
4088 return 0;
4089
4090 char_kobj_err:
4091 kobject_put(kobj: sysfs_dev_block_kobj);
4092 block_kobj_err:
4093 kobject_put(kobj: dev_kobj);
4094 dev_kobj_err:
4095 kset_unregister(kset: devices_kset);
4096 return -ENOMEM;
4097}
4098
4099static int device_check_offline(struct device *dev, void *not_used)
4100{
4101 int ret;
4102
4103 ret = device_for_each_child(dev, NULL, device_check_offline);
4104 if (ret)
4105 return ret;
4106
4107 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
4108}
4109
4110/**
4111 * device_offline - Prepare the device for hot-removal.
4112 * @dev: Device to be put offline.
4113 *
4114 * Execute the device bus type's .offline() callback, if present, to prepare
4115 * the device for a subsequent hot-removal. If that succeeds, the device must
4116 * not be used until either it is removed or its bus type's .online() callback
4117 * is executed.
4118 *
4119 * Call under device_hotplug_lock.
4120 */
4121int device_offline(struct device *dev)
4122{
4123 int ret;
4124
4125 if (dev->offline_disabled)
4126 return -EPERM;
4127
4128 ret = device_for_each_child(dev, NULL, device_check_offline);
4129 if (ret)
4130 return ret;
4131
4132 device_lock(dev);
4133 if (device_supports_offline(dev)) {
4134 if (dev->offline) {
4135 ret = 1;
4136 } else {
4137 ret = dev->bus->offline(dev);
4138 if (!ret) {
4139 kobject_uevent(kobj: &dev->kobj, action: KOBJ_OFFLINE);
4140 dev->offline = true;
4141 }
4142 }
4143 }
4144 device_unlock(dev);
4145
4146 return ret;
4147}
4148
4149/**
4150 * device_online - Put the device back online after successful device_offline().
4151 * @dev: Device to be put back online.
4152 *
4153 * If device_offline() has been successfully executed for @dev, but the device
4154 * has not been removed subsequently, execute its bus type's .online() callback
4155 * to indicate that the device can be used again.
4156 *
4157 * Call under device_hotplug_lock.
4158 */
4159int device_online(struct device *dev)
4160{
4161 int ret = 0;
4162
4163 device_lock(dev);
4164 if (device_supports_offline(dev)) {
4165 if (dev->offline) {
4166 ret = dev->bus->online(dev);
4167 if (!ret) {
4168 kobject_uevent(kobj: &dev->kobj, action: KOBJ_ONLINE);
4169 dev->offline = false;
4170 }
4171 } else {
4172 ret = 1;
4173 }
4174 }
4175 device_unlock(dev);
4176
4177 return ret;
4178}
4179
4180struct root_device {
4181 struct device dev;
4182 struct module *owner;
4183};
4184
4185static inline struct root_device *to_root_device(struct device *d)
4186{
4187 return container_of(d, struct root_device, dev);
4188}
4189
4190static void root_device_release(struct device *dev)
4191{
4192 kfree(objp: to_root_device(d: dev));
4193}
4194
4195/**
4196 * __root_device_register - allocate and register a root device
4197 * @name: root device name
4198 * @owner: owner module of the root device, usually THIS_MODULE
4199 *
4200 * This function allocates a root device and registers it
4201 * using device_register(). In order to free the returned
4202 * device, use root_device_unregister().
4203 *
4204 * Root devices are dummy devices which allow other devices
4205 * to be grouped under /sys/devices. Use this function to
4206 * allocate a root device and then use it as the parent of
4207 * any device which should appear under /sys/devices/{name}
4208 *
4209 * The /sys/devices/{name} directory will also contain a
4210 * 'module' symlink which points to the @owner directory
4211 * in sysfs.
4212 *
4213 * Returns &struct device pointer on success, or ERR_PTR() on error.
4214 *
4215 * Note: You probably want to use root_device_register().
4216 */
4217struct device *__root_device_register(const char *name, struct module *owner)
4218{
4219 struct root_device *root;
4220 int err = -ENOMEM;
4221
4222 root = kzalloc(size: sizeof(struct root_device), GFP_KERNEL);
4223 if (!root)
4224 return ERR_PTR(error: err);
4225
4226 err = dev_set_name(&root->dev, "%s", name);
4227 if (err) {
4228 kfree(objp: root);
4229 return ERR_PTR(error: err);
4230 }
4231
4232 root->dev.release = root_device_release;
4233
4234 err = device_register(&root->dev);
4235 if (err) {
4236 put_device(&root->dev);
4237 return ERR_PTR(error: err);
4238 }
4239
4240#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
4241 if (owner) {
4242 struct module_kobject *mk = &owner->mkobj;
4243
4244 err = sysfs_create_link(kobj: &root->dev.kobj, target: &mk->kobj, name: "module");
4245 if (err) {
4246 device_unregister(&root->dev);
4247 return ERR_PTR(error: err);
4248 }
4249 root->owner = owner;
4250 }
4251#endif
4252
4253 return &root->dev;
4254}
4255EXPORT_SYMBOL_GPL(__root_device_register);
4256
4257/**
4258 * root_device_unregister - unregister and free a root device
4259 * @dev: device going away
4260 *
4261 * This function unregisters and cleans up a device that was created by
4262 * root_device_register().
4263 */
4264void root_device_unregister(struct device *dev)
4265{
4266 struct root_device *root = to_root_device(d: dev);
4267
4268 if (root->owner)
4269 sysfs_remove_link(kobj: &root->dev.kobj, name: "module");
4270
4271 device_unregister(dev);
4272}
4273EXPORT_SYMBOL_GPL(root_device_unregister);
4274
4275
4276static void device_create_release(struct device *dev)
4277{
4278 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
4279 kfree(objp: dev);
4280}
4281
4282static __printf(6, 0) struct device *
4283device_create_groups_vargs(const struct class *class, struct device *parent,
4284 dev_t devt, void *drvdata,
4285 const struct attribute_group **groups,
4286 const char *fmt, va_list args)
4287{
4288 struct device *dev = NULL;
4289 int retval = -ENODEV;
4290
4291 if (IS_ERR_OR_NULL(ptr: class))
4292 goto error;
4293
4294 dev = kzalloc(size: sizeof(*dev), GFP_KERNEL);
4295 if (!dev) {
4296 retval = -ENOMEM;
4297 goto error;
4298 }
4299
4300 device_initialize(dev);
4301 dev->devt = devt;
4302 dev->class = class;
4303 dev->parent = parent;
4304 dev->groups = groups;
4305 dev->release = device_create_release;
4306 dev_set_drvdata(dev, data: drvdata);
4307
4308 retval = kobject_set_name_vargs(kobj: &dev->kobj, fmt, vargs: args);
4309 if (retval)
4310 goto error;
4311
4312 retval = device_add(dev);
4313 if (retval)
4314 goto error;
4315
4316 return dev;
4317
4318error:
4319 put_device(dev);
4320 return ERR_PTR(error: retval);
4321}
4322
4323/**
4324 * device_create - creates a device and registers it with sysfs
4325 * @class: pointer to the struct class that this device should be registered to
4326 * @parent: pointer to the parent struct device of this new device, if any
4327 * @devt: the dev_t for the char device to be added
4328 * @drvdata: the data to be added to the device for callbacks
4329 * @fmt: string for the device's name
4330 *
4331 * This function can be used by char device classes. A struct device
4332 * will be created in sysfs, registered to the specified class.
4333 *
4334 * A "dev" file will be created, showing the dev_t for the device, if
4335 * the dev_t is not 0,0.
4336 * If a pointer to a parent struct device is passed in, the newly created
4337 * struct device will be a child of that device in sysfs.
4338 * The pointer to the struct device will be returned from the call.
4339 * Any further sysfs files that might be required can be created using this
4340 * pointer.
4341 *
4342 * Returns &struct device pointer on success, or ERR_PTR() on error.
4343 */
4344struct device *device_create(const struct class *class, struct device *parent,
4345 dev_t devt, void *drvdata, const char *fmt, ...)
4346{
4347 va_list vargs;
4348 struct device *dev;
4349
4350 va_start(vargs, fmt);
4351 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
4352 fmt, args: vargs);
4353 va_end(vargs);
4354 return dev;
4355}
4356EXPORT_SYMBOL_GPL(device_create);
4357
4358/**
4359 * device_create_with_groups - creates a device and registers it with sysfs
4360 * @class: pointer to the struct class that this device should be registered to
4361 * @parent: pointer to the parent struct device of this new device, if any
4362 * @devt: the dev_t for the char device to be added
4363 * @drvdata: the data to be added to the device for callbacks
4364 * @groups: NULL-terminated list of attribute groups to be created
4365 * @fmt: string for the device's name
4366 *
4367 * This function can be used by char device classes. A struct device
4368 * will be created in sysfs, registered to the specified class.
4369 * Additional attributes specified in the groups parameter will also
4370 * be created automatically.
4371 *
4372 * A "dev" file will be created, showing the dev_t for the device, if
4373 * the dev_t is not 0,0.
4374 * If a pointer to a parent struct device is passed in, the newly created
4375 * struct device will be a child of that device in sysfs.
4376 * The pointer to the struct device will be returned from the call.
4377 * Any further sysfs files that might be required can be created using this
4378 * pointer.
4379 *
4380 * Returns &struct device pointer on success, or ERR_PTR() on error.
4381 */
4382struct device *device_create_with_groups(const struct class *class,
4383 struct device *parent, dev_t devt,
4384 void *drvdata,
4385 const struct attribute_group **groups,
4386 const char *fmt, ...)
4387{
4388 va_list vargs;
4389 struct device *dev;
4390
4391 va_start(vargs, fmt);
4392 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
4393 fmt, args: vargs);
4394 va_end(vargs);
4395 return dev;
4396}
4397EXPORT_SYMBOL_GPL(device_create_with_groups);
4398
4399/**
4400 * device_destroy - removes a device that was created with device_create()
4401 * @class: pointer to the struct class that this device was registered with
4402 * @devt: the dev_t of the device that was previously registered
4403 *
4404 * This call unregisters and cleans up a device that was created with a
4405 * call to device_create().
4406 */
4407void device_destroy(const struct class *class, dev_t devt)
4408{
4409 struct device *dev;
4410
4411 dev = class_find_device_by_devt(class, devt);
4412 if (dev) {
4413 put_device(dev);
4414 device_unregister(dev);
4415 }
4416}
4417EXPORT_SYMBOL_GPL(device_destroy);
4418
4419/**
4420 * device_rename - renames a device
4421 * @dev: the pointer to the struct device to be renamed
4422 * @new_name: the new name of the device
4423 *
4424 * It is the responsibility of the caller to provide mutual
4425 * exclusion between two different calls of device_rename
4426 * on the same device to ensure that new_name is valid and
4427 * won't conflict with other devices.
4428 *
4429 * Note: given that some subsystems (networking and infiniband) use this
4430 * function, with no immediate plans for this to change, we cannot assume or
4431 * require that this function not be called at all.
4432 *
4433 * However, if you're writing new code, do not call this function. The following
4434 * text from Kay Sievers offers some insight:
4435 *
4436 * Renaming devices is racy at many levels, symlinks and other stuff are not
4437 * replaced atomically, and you get a "move" uevent, but it's not easy to
4438 * connect the event to the old and new device. Device nodes are not renamed at
4439 * all, there isn't even support for that in the kernel now.
4440 *
4441 * In the meantime, during renaming, your target name might be taken by another
4442 * driver, creating conflicts. Or the old name is taken directly after you
4443 * renamed it -- then you get events for the same DEVPATH, before you even see
4444 * the "move" event. It's just a mess, and nothing new should ever rely on
4445 * kernel device renaming. Besides that, it's not even implemented now for
4446 * other things than (driver-core wise very simple) network devices.
4447 *
4448 * Make up a "real" name in the driver before you register anything, or add
4449 * some other attributes for userspace to find the device, or use udev to add
4450 * symlinks -- but never rename kernel devices later, it's a complete mess. We
4451 * don't even want to get into that and try to implement the missing pieces in
4452 * the core. We really have other pieces to fix in the driver core mess. :)
4453 */
4454int device_rename(struct device *dev, const char *new_name)
4455{
4456 struct kobject *kobj = &dev->kobj;
4457 char *old_device_name = NULL;
4458 int error;
4459
4460 dev = get_device(dev);
4461 if (!dev)
4462 return -EINVAL;
4463
4464 dev_dbg(dev, "renaming to %s\n", new_name);
4465
4466 old_device_name = kstrdup(s: dev_name(dev), GFP_KERNEL);
4467 if (!old_device_name) {
4468 error = -ENOMEM;
4469 goto out;
4470 }
4471
4472 if (dev->class) {
4473 struct subsys_private *sp = class_to_subsys(class: dev->class);
4474
4475 if (!sp) {
4476 error = -EINVAL;
4477 goto out;
4478 }
4479
4480 error = sysfs_rename_link_ns(kobj: &sp->subsys.kobj, target: kobj, old_name: old_device_name,
4481 new_name, new_ns: kobject_namespace(kobj));
4482 subsys_put(sp);
4483 if (error)
4484 goto out;
4485 }
4486
4487 error = kobject_rename(kobj, new_name);
4488 if (error)
4489 goto out;
4490
4491out:
4492 put_device(dev);
4493
4494 kfree(objp: old_device_name);
4495
4496 return error;
4497}
4498EXPORT_SYMBOL_GPL(device_rename);
4499
4500static int device_move_class_links(struct device *dev,
4501 struct device *old_parent,
4502 struct device *new_parent)
4503{
4504 int error = 0;
4505
4506 if (old_parent)
4507 sysfs_remove_link(kobj: &dev->kobj, name: "device");
4508 if (new_parent)
4509 error = sysfs_create_link(kobj: &dev->kobj, target: &new_parent->kobj,
4510 name: "device");
4511 return error;
4512}
4513
4514/**
4515 * device_move - moves a device to a new parent
4516 * @dev: the pointer to the struct device to be moved
4517 * @new_parent: the new parent of the device (can be NULL)
4518 * @dpm_order: how to reorder the dpm_list
4519 */
4520int device_move(struct device *dev, struct device *new_parent,
4521 enum dpm_order dpm_order)
4522{
4523 int error;
4524 struct device *old_parent;
4525 struct kobject *new_parent_kobj;
4526
4527 dev = get_device(dev);
4528 if (!dev)
4529 return -EINVAL;
4530
4531 device_pm_lock();
4532 new_parent = get_device(new_parent);
4533 new_parent_kobj = get_device_parent(dev, parent: new_parent);
4534 if (IS_ERR(ptr: new_parent_kobj)) {
4535 error = PTR_ERR(ptr: new_parent_kobj);
4536 put_device(new_parent);
4537 goto out;
4538 }
4539
4540 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
4541 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
4542 error = kobject_move(&dev->kobj, new_parent_kobj);
4543 if (error) {
4544 cleanup_glue_dir(dev, glue_dir: new_parent_kobj);
4545 put_device(new_parent);
4546 goto out;
4547 }
4548 old_parent = dev->parent;
4549 dev->parent = new_parent;
4550 if (old_parent)
4551 klist_remove(n: &dev->p->knode_parent);
4552 if (new_parent) {
4553 klist_add_tail(n: &dev->p->knode_parent,
4554 k: &new_parent->p->klist_children);
4555 set_dev_node(dev, node: dev_to_node(dev: new_parent));
4556 }
4557
4558 if (dev->class) {
4559 error = device_move_class_links(dev, old_parent, new_parent);
4560 if (error) {
4561 /* We ignore errors on cleanup since we're hosed anyway... */
4562 device_move_class_links(dev, old_parent: new_parent, new_parent: old_parent);
4563 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
4564 if (new_parent)
4565 klist_remove(n: &dev->p->knode_parent);
4566 dev->parent = old_parent;
4567 if (old_parent) {
4568 klist_add_tail(n: &dev->p->knode_parent,
4569 k: &old_parent->p->klist_children);
4570 set_dev_node(dev, node: dev_to_node(dev: old_parent));
4571 }
4572 }
4573 cleanup_glue_dir(dev, glue_dir: new_parent_kobj);
4574 put_device(new_parent);
4575 goto out;
4576 }
4577 }
4578 switch (dpm_order) {
4579 case DPM_ORDER_NONE:
4580 break;
4581 case DPM_ORDER_DEV_AFTER_PARENT:
4582 device_pm_move_after(dev, new_parent);
4583 devices_kset_move_after(deva: dev, devb: new_parent);
4584 break;
4585 case DPM_ORDER_PARENT_BEFORE_DEV:
4586 device_pm_move_before(new_parent, dev);
4587 devices_kset_move_before(deva: new_parent, devb: dev);
4588 break;
4589 case DPM_ORDER_DEV_LAST:
4590 device_pm_move_last(dev);
4591 devices_kset_move_last(dev);
4592 break;
4593 }
4594
4595 put_device(old_parent);
4596out:
4597 device_pm_unlock();
4598 put_device(dev);
4599 return error;
4600}
4601EXPORT_SYMBOL_GPL(device_move);
4602
4603static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
4604 kgid_t kgid)
4605{
4606 struct kobject *kobj = &dev->kobj;
4607 const struct class *class = dev->class;
4608 const struct device_type *type = dev->type;
4609 int error;
4610
4611 if (class) {
4612 /*
4613 * Change the device groups of the device class for @dev to
4614 * @kuid/@kgid.
4615 */
4616 error = sysfs_groups_change_owner(kobj, groups: class->dev_groups, kuid,
4617 kgid);
4618 if (error)
4619 return error;
4620 }
4621
4622 if (type) {
4623 /*
4624 * Change the device groups of the device type for @dev to
4625 * @kuid/@kgid.
4626 */
4627 error = sysfs_groups_change_owner(kobj, groups: type->groups, kuid,
4628 kgid);
4629 if (error)
4630 return error;
4631 }
4632
4633 /* Change the device groups of @dev to @kuid/@kgid. */
4634 error = sysfs_groups_change_owner(kobj, groups: dev->groups, kuid, kgid);
4635 if (error)
4636 return error;
4637
4638 if (device_supports_offline(dev) && !dev->offline_disabled) {
4639 /* Change online device attributes of @dev to @kuid/@kgid. */
4640 error = sysfs_file_change_owner(kobj, name: dev_attr_online.attr.name,
4641 kuid, kgid);
4642 if (error)
4643 return error;
4644 }
4645
4646 return 0;
4647}
4648
4649/**
4650 * device_change_owner - change the owner of an existing device.
4651 * @dev: device.
4652 * @kuid: new owner's kuid
4653 * @kgid: new owner's kgid
4654 *
4655 * This changes the owner of @dev and its corresponding sysfs entries to
4656 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
4657 * core.
4658 *
4659 * Returns 0 on success or error code on failure.
4660 */
4661int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
4662{
4663 int error;
4664 struct kobject *kobj = &dev->kobj;
4665 struct subsys_private *sp;
4666
4667 dev = get_device(dev);
4668 if (!dev)
4669 return -EINVAL;
4670
4671 /*
4672 * Change the kobject and the default attributes and groups of the
4673 * ktype associated with it to @kuid/@kgid.
4674 */
4675 error = sysfs_change_owner(kobj, kuid, kgid);
4676 if (error)
4677 goto out;
4678
4679 /*
4680 * Change the uevent file for @dev to the new owner. The uevent file
4681 * was created in a separate step when @dev got added and we mirror
4682 * that step here.
4683 */
4684 error = sysfs_file_change_owner(kobj, name: dev_attr_uevent.attr.name, kuid,
4685 kgid);
4686 if (error)
4687 goto out;
4688
4689 /*
4690 * Change the device groups, the device groups associated with the
4691 * device class, and the groups associated with the device type of @dev
4692 * to @kuid/@kgid.
4693 */
4694 error = device_attrs_change_owner(dev, kuid, kgid);
4695 if (error)
4696 goto out;
4697
4698 error = dpm_sysfs_change_owner(dev, kuid, kgid);
4699 if (error)
4700 goto out;
4701
4702 /*
4703 * Change the owner of the symlink located in the class directory of
4704 * the device class associated with @dev which points to the actual
4705 * directory entry for @dev to @kuid/@kgid. This ensures that the
4706 * symlink shows the same permissions as its target.
4707 */
4708 sp = class_to_subsys(class: dev->class);
4709 if (!sp) {
4710 error = -EINVAL;
4711 goto out;
4712 }
4713 error = sysfs_link_change_owner(kobj: &sp->subsys.kobj, targ: &dev->kobj, name: dev_name(dev), kuid, kgid);
4714 subsys_put(sp);
4715
4716out:
4717 put_device(dev);
4718 return error;
4719}
4720EXPORT_SYMBOL_GPL(device_change_owner);
4721
4722/**
4723 * device_shutdown - call ->shutdown() on each device to shutdown.
4724 */
4725void device_shutdown(void)
4726{
4727 struct device *dev, *parent;
4728
4729 wait_for_device_probe();
4730 device_block_probing();
4731
4732 cpufreq_suspend();
4733
4734 spin_lock(lock: &devices_kset->list_lock);
4735 /*
4736 * Walk the devices list backward, shutting down each in turn.
4737 * Beware that device unplug events may also start pulling
4738 * devices offline, even as the system is shutting down.
4739 */
4740 while (!list_empty(head: &devices_kset->list)) {
4741 dev = list_entry(devices_kset->list.prev, struct device,
4742 kobj.entry);
4743
4744 /*
4745 * hold reference count of device's parent to
4746 * prevent it from being freed because parent's
4747 * lock is to be held
4748 */
4749 parent = get_device(dev->parent);
4750 get_device(dev);
4751 /*
4752 * Make sure the device is off the kset list, in the
4753 * event that dev->*->shutdown() doesn't remove it.
4754 */
4755 list_del_init(entry: &dev->kobj.entry);
4756 spin_unlock(lock: &devices_kset->list_lock);
4757
4758 /* hold lock to avoid race with probe/release */
4759 if (parent)
4760 device_lock(dev: parent);
4761 device_lock(dev);
4762
4763 /* Don't allow any more runtime suspends */
4764 pm_runtime_get_noresume(dev);
4765 pm_runtime_barrier(dev);
4766
4767 if (dev->class && dev->class->shutdown_pre) {
4768 if (initcall_debug)
4769 dev_info(dev, "shutdown_pre\n");
4770 dev->class->shutdown_pre(dev);
4771 }
4772 if (dev->bus && dev->bus->shutdown) {
4773 if (initcall_debug)
4774 dev_info(dev, "shutdown\n");
4775 dev->bus->shutdown(dev);
4776 } else if (dev->driver && dev->driver->shutdown) {
4777 if (initcall_debug)
4778 dev_info(dev, "shutdown\n");
4779 dev->driver->shutdown(dev);
4780 }
4781
4782 device_unlock(dev);
4783 if (parent)
4784 device_unlock(dev: parent);
4785
4786 put_device(dev);
4787 put_device(parent);
4788
4789 spin_lock(lock: &devices_kset->list_lock);
4790 }
4791 spin_unlock(lock: &devices_kset->list_lock);
4792}
4793
4794/*
4795 * Device logging functions
4796 */
4797
4798#ifdef CONFIG_PRINTK
4799static void
4800set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4801{
4802 const char *subsys;
4803
4804 memset(dev_info, 0, sizeof(*dev_info));
4805
4806 if (dev->class)
4807 subsys = dev->class->name;
4808 else if (dev->bus)
4809 subsys = dev->bus->name;
4810 else
4811 return;
4812
4813 strscpy(p: dev_info->subsystem, q: subsys, size: sizeof(dev_info->subsystem));
4814
4815 /*
4816 * Add device identifier DEVICE=:
4817 * b12:8 block dev_t
4818 * c127:3 char dev_t
4819 * n8 netdev ifindex
4820 * +sound:card0 subsystem:devname
4821 */
4822 if (MAJOR(dev->devt)) {
4823 char c;
4824
4825 if (strcmp(subsys, "block") == 0)
4826 c = 'b';
4827 else
4828 c = 'c';
4829
4830 snprintf(buf: dev_info->device, size: sizeof(dev_info->device),
4831 fmt: "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4832 } else if (strcmp(subsys, "net") == 0) {
4833 struct net_device *net = to_net_dev(dev);
4834
4835 snprintf(buf: dev_info->device, size: sizeof(dev_info->device),
4836 fmt: "n%u", net->ifindex);
4837 } else {
4838 snprintf(buf: dev_info->device, size: sizeof(dev_info->device),
4839 fmt: "+%s:%s", subsys, dev_name(dev));
4840 }
4841}
4842
4843int dev_vprintk_emit(int level, const struct device *dev,
4844 const char *fmt, va_list args)
4845{
4846 struct dev_printk_info dev_info;
4847
4848 set_dev_info(dev, dev_info: &dev_info);
4849
4850 return vprintk_emit(facility: 0, level, dev_info: &dev_info, fmt, args);
4851}
4852EXPORT_SYMBOL(dev_vprintk_emit);
4853
4854int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4855{
4856 va_list args;
4857 int r;
4858
4859 va_start(args, fmt);
4860
4861 r = dev_vprintk_emit(level, dev, fmt, args);
4862
4863 va_end(args);
4864
4865 return r;
4866}
4867EXPORT_SYMBOL(dev_printk_emit);
4868
4869static void __dev_printk(const char *level, const struct device *dev,
4870 struct va_format *vaf)
4871{
4872 if (dev)
4873 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4874 dev_driver_string(dev), dev_name(dev), vaf);
4875 else
4876 printk("%s(NULL device *): %pV", level, vaf);
4877}
4878
4879void _dev_printk(const char *level, const struct device *dev,
4880 const char *fmt, ...)
4881{
4882 struct va_format vaf;
4883 va_list args;
4884
4885 va_start(args, fmt);
4886
4887 vaf.fmt = fmt;
4888 vaf.va = &args;
4889
4890 __dev_printk(level, dev, vaf: &vaf);
4891
4892 va_end(args);
4893}
4894EXPORT_SYMBOL(_dev_printk);
4895
4896#define define_dev_printk_level(func, kern_level) \
4897void func(const struct device *dev, const char *fmt, ...) \
4898{ \
4899 struct va_format vaf; \
4900 va_list args; \
4901 \
4902 va_start(args, fmt); \
4903 \
4904 vaf.fmt = fmt; \
4905 vaf.va = &args; \
4906 \
4907 __dev_printk(kern_level, dev, &vaf); \
4908 \
4909 va_end(args); \
4910} \
4911EXPORT_SYMBOL(func);
4912
4913define_dev_printk_level(_dev_emerg, KERN_EMERG);
4914define_dev_printk_level(_dev_alert, KERN_ALERT);
4915define_dev_printk_level(_dev_crit, KERN_CRIT);
4916define_dev_printk_level(_dev_err, KERN_ERR);
4917define_dev_printk_level(_dev_warn, KERN_WARNING);
4918define_dev_printk_level(_dev_notice, KERN_NOTICE);
4919define_dev_printk_level(_dev_info, KERN_INFO);
4920
4921#endif
4922
4923/**
4924 * dev_err_probe - probe error check and log helper
4925 * @dev: the pointer to the struct device
4926 * @err: error value to test
4927 * @fmt: printf-style format string
4928 * @...: arguments as specified in the format string
4929 *
4930 * This helper implements common pattern present in probe functions for error
4931 * checking: print debug or error message depending if the error value is
4932 * -EPROBE_DEFER and propagate error upwards.
4933 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
4934 * checked later by reading devices_deferred debugfs attribute.
4935 * It replaces code sequence::
4936 *
4937 * if (err != -EPROBE_DEFER)
4938 * dev_err(dev, ...);
4939 * else
4940 * dev_dbg(dev, ...);
4941 * return err;
4942 *
4943 * with::
4944 *
4945 * return dev_err_probe(dev, err, ...);
4946 *
4947 * Note that it is deemed acceptable to use this function for error
4948 * prints during probe even if the @err is known to never be -EPROBE_DEFER.
4949 * The benefit compared to a normal dev_err() is the standardized format
4950 * of the error code and the fact that the error code is returned.
4951 *
4952 * Returns @err.
4953 *
4954 */
4955int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
4956{
4957 struct va_format vaf;
4958 va_list args;
4959
4960 va_start(args, fmt);
4961 vaf.fmt = fmt;
4962 vaf.va = &args;
4963
4964 if (err != -EPROBE_DEFER) {
4965 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4966 } else {
4967 device_set_deferred_probe_reason(dev, vaf: &vaf);
4968 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4969 }
4970
4971 va_end(args);
4972
4973 return err;
4974}
4975EXPORT_SYMBOL_GPL(dev_err_probe);
4976
4977static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
4978{
4979 return fwnode && !IS_ERR(ptr: fwnode->secondary);
4980}
4981
4982/**
4983 * set_primary_fwnode - Change the primary firmware node of a given device.
4984 * @dev: Device to handle.
4985 * @fwnode: New primary firmware node of the device.
4986 *
4987 * Set the device's firmware node pointer to @fwnode, but if a secondary
4988 * firmware node of the device is present, preserve it.
4989 *
4990 * Valid fwnode cases are:
4991 * - primary --> secondary --> -ENODEV
4992 * - primary --> NULL
4993 * - secondary --> -ENODEV
4994 * - NULL
4995 */
4996void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4997{
4998 struct device *parent = dev->parent;
4999 struct fwnode_handle *fn = dev->fwnode;
5000
5001 if (fwnode) {
5002 if (fwnode_is_primary(fwnode: fn))
5003 fn = fn->secondary;
5004
5005 if (fn) {
5006 WARN_ON(fwnode->secondary);
5007 fwnode->secondary = fn;
5008 }
5009 dev->fwnode = fwnode;
5010 } else {
5011 if (fwnode_is_primary(fwnode: fn)) {
5012 dev->fwnode = fn->secondary;
5013
5014 /* Skip nullifying fn->secondary if the primary is shared */
5015 if (parent && fn == parent->fwnode)
5016 return;
5017
5018 /* Set fn->secondary = NULL, so fn remains the primary fwnode */
5019 fn->secondary = NULL;
5020 } else {
5021 dev->fwnode = NULL;
5022 }
5023 }
5024}
5025EXPORT_SYMBOL_GPL(set_primary_fwnode);
5026
5027/**
5028 * set_secondary_fwnode - Change the secondary firmware node of a given device.
5029 * @dev: Device to handle.
5030 * @fwnode: New secondary firmware node of the device.
5031 *
5032 * If a primary firmware node of the device is present, set its secondary
5033 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
5034 * @fwnode.
5035 */
5036void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
5037{
5038 if (fwnode)
5039 fwnode->secondary = ERR_PTR(error: -ENODEV);
5040
5041 if (fwnode_is_primary(fwnode: dev->fwnode))
5042 dev->fwnode->secondary = fwnode;
5043 else
5044 dev->fwnode = fwnode;
5045}
5046EXPORT_SYMBOL_GPL(set_secondary_fwnode);
5047
5048/**
5049 * device_set_of_node_from_dev - reuse device-tree node of another device
5050 * @dev: device whose device-tree node is being set
5051 * @dev2: device whose device-tree node is being reused
5052 *
5053 * Takes another reference to the new device-tree node after first dropping
5054 * any reference held to the old node.
5055 */
5056void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
5057{
5058 of_node_put(node: dev->of_node);
5059 dev->of_node = of_node_get(node: dev2->of_node);
5060 dev->of_node_reused = true;
5061}
5062EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
5063
5064void device_set_node(struct device *dev, struct fwnode_handle *fwnode)
5065{
5066 dev->fwnode = fwnode;
5067 dev->of_node = to_of_node(fwnode);
5068}
5069EXPORT_SYMBOL_GPL(device_set_node);
5070
5071int device_match_name(struct device *dev, const void *name)
5072{
5073 return sysfs_streq(s1: dev_name(dev), s2: name);
5074}
5075EXPORT_SYMBOL_GPL(device_match_name);
5076
5077int device_match_of_node(struct device *dev, const void *np)
5078{
5079 return dev->of_node == np;
5080}
5081EXPORT_SYMBOL_GPL(device_match_of_node);
5082
5083int device_match_fwnode(struct device *dev, const void *fwnode)
5084{
5085 return dev_fwnode(dev) == fwnode;
5086}
5087EXPORT_SYMBOL_GPL(device_match_fwnode);
5088
5089int device_match_devt(struct device *dev, const void *pdevt)
5090{
5091 return dev->devt == *(dev_t *)pdevt;
5092}
5093EXPORT_SYMBOL_GPL(device_match_devt);
5094
5095int device_match_acpi_dev(struct device *dev, const void *adev)
5096{
5097 return ACPI_COMPANION(dev) == adev;
5098}
5099EXPORT_SYMBOL(device_match_acpi_dev);
5100
5101int device_match_acpi_handle(struct device *dev, const void *handle)
5102{
5103 return ACPI_HANDLE(dev) == handle;
5104}
5105EXPORT_SYMBOL(device_match_acpi_handle);
5106
5107int device_match_any(struct device *dev, const void *unused)
5108{
5109 return 1;
5110}
5111EXPORT_SYMBOL_GPL(device_match_any);
5112

source code of linux/drivers/base/core.c