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