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