projects/linux·blob v3.13 · refs

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1/*
2 * drivers/base/devres.c - device resource management
3 *
4 * Copyright (c) 2006 SUSE Linux Products GmbH
5 * Copyright (c) 2006 Tejun Heo <[email protected]>
6 *
7 * This file is released under the GPLv2.
8 */
9
10#include <linux/device.h>
11#include <linux/module.h>
12#include <linux/slab.h>
13
14#include "base.h"
15
16struct devres_node {
17 struct list_head entry;
18 dr_release_t release;
19#ifdef CONFIG_DEBUG_DEVRES
20 const char *name;
21 size_t size;
22#endif
23};
24
25struct devres {
26 struct devres_node node;
27 /* -- 3 pointers */
28 unsigned long long data[]; /* guarantee ull alignment */
29};
30
31struct devres_group {
32 struct devres_node node[2];
33 void *id;
34 int color;
35 /* -- 8 pointers */
36};
37
38#ifdef CONFIG_DEBUG_DEVRES
39static int log_devres = 0;
40module_param_named(log, log_devres, int, S_IRUGO | S_IWUSR);
41
42static void set_node_dbginfo(struct devres_node *node, const char *name,
43 size_t size)
44{
45 node->name = name;
46 node->size = size;
47}
48
49static void devres_log(struct device *dev, struct devres_node *node,
50 const char *op)
51{
52 if (unlikely(log_devres))
53 dev_err(dev, "DEVRES %3s %p %s (%lu bytes)\n",
54 op, node, node->name, (unsigned long)node->size);
55}
56#else /* CONFIG_DEBUG_DEVRES */
57#define set_node_dbginfo(node, n, s) do {} while (0)
58#define devres_log(dev, node, op) do {} while (0)
59#endif /* CONFIG_DEBUG_DEVRES */
60
61/*
62 * Release functions for devres group. These callbacks are used only
63 * for identification.
64 */
65static void group_open_release(struct device *dev, void *res)
66{
67 /* noop */
68}
69
70static void group_close_release(struct device *dev, void *res)
71{
72 /* noop */
73}
74
75static struct devres_group * node_to_group(struct devres_node *node)
76{
77 if (node->release == &group_open_release)
78 return container_of(node, struct devres_group, node[0]);
79 if (node->release == &group_close_release)
80 return container_of(node, struct devres_group, node[1]);
81 return NULL;
82}
83
84static __always_inline struct devres * alloc_dr(dr_release_t release,
85 size_t size, gfp_t gfp)
86{
87 size_t tot_size = sizeof(struct devres) + size;
88 struct devres *dr;
89
90 dr = kmalloc_track_caller(tot_size, gfp);
91 if (unlikely(!dr))
92 return NULL;
93
94 memset(dr, 0, offsetof(struct devres, data));
95
96 INIT_LIST_HEAD(&dr->node.entry);
97 dr->node.release = release;
98 return dr;
99}
100
101static void add_dr(struct device *dev, struct devres_node *node)
102{
103 devres_log(dev, node, "ADD");
104 BUG_ON(!list_empty(&node->entry));
105 list_add_tail(&node->entry, &dev->devres_head);
106}
107
108#ifdef CONFIG_DEBUG_DEVRES
109void * __devres_alloc(dr_release_t release, size_t size, gfp_t gfp,
110 const char *name)
111{
112 struct devres *dr;
113
114 dr = alloc_dr(release, size, gfp | __GFP_ZERO);
115 if (unlikely(!dr))
116 return NULL;
117 set_node_dbginfo(&dr->node, name, size);
118 return dr->data;
119}
120EXPORT_SYMBOL_GPL(__devres_alloc);
121#else
122/**
123 * devres_alloc - Allocate device resource data
124 * @release: Release function devres will be associated with
125 * @size: Allocation size
126 * @gfp: Allocation flags
127 *
128 * Allocate devres of @size bytes. The allocated area is zeroed, then
129 * associated with @release. The returned pointer can be passed to
130 * other devres_*() functions.
131 *
132 * RETURNS:
133 * Pointer to allocated devres on success, NULL on failure.
134 */
135void * devres_alloc(dr_release_t release, size_t size, gfp_t gfp)
136{
137 struct devres *dr;
138
139 dr = alloc_dr(release, size, gfp | __GFP_ZERO);
140 if (unlikely(!dr))
141 return NULL;
142 return dr->data;
143}
144EXPORT_SYMBOL_GPL(devres_alloc);
145#endif
146
147/**
148 * devres_for_each_res - Resource iterator
149 * @dev: Device to iterate resource from
150 * @release: Look for resources associated with this release function
151 * @match: Match function (optional)
152 * @match_data: Data for the match function
153 * @fn: Function to be called for each matched resource.
154 * @data: Data for @fn, the 3rd parameter of @fn
155 *
156 * Call @fn for each devres of @dev which is associated with @release
157 * and for which @match returns 1.
158 *
159 * RETURNS:
160 * void
161 */
162void devres_for_each_res(struct device *dev, dr_release_t release,
163 dr_match_t match, void *match_data,
164 void (*fn)(struct device *, void *, void *),
165 void *data)
166{
167 struct devres_node *node;
168 struct devres_node *tmp;
169 unsigned long flags;
170
171 if (!fn)
172 return;
173
174 spin_lock_irqsave(&dev->devres_lock, flags);
175 list_for_each_entry_safe_reverse(node, tmp,
176 &dev->devres_head, entry) {
177 struct devres *dr = container_of(node, struct devres, node);
178
179 if (node->release != release)
180 continue;
181 if (match && !match(dev, dr->data, match_data))
182 continue;
183 fn(dev, dr->data, data);
184 }
185 spin_unlock_irqrestore(&dev->devres_lock, flags);
186}
187EXPORT_SYMBOL_GPL(devres_for_each_res);
188
189/**
190 * devres_free - Free device resource data
191 * @res: Pointer to devres data to free
192 *
193 * Free devres created with devres_alloc().
194 */
195void devres_free(void *res)
196{
197 if (res) {
198 struct devres *dr = container_of(res, struct devres, data);
199
200 BUG_ON(!list_empty(&dr->node.entry));
201 kfree(dr);
202 }
203}
204EXPORT_SYMBOL_GPL(devres_free);
205
206/**
207 * devres_add - Register device resource
208 * @dev: Device to add resource to
209 * @res: Resource to register
210 *
211 * Register devres @res to @dev. @res should have been allocated
212 * using devres_alloc(). On driver detach, the associated release
213 * function will be invoked and devres will be freed automatically.
214 */
215void devres_add(struct device *dev, void *res)
216{
217 struct devres *dr = container_of(res, struct devres, data);
218 unsigned long flags;
219
220 spin_lock_irqsave(&dev->devres_lock, flags);
221 add_dr(dev, &dr->node);
222 spin_unlock_irqrestore(&dev->devres_lock, flags);
223}
224EXPORT_SYMBOL_GPL(devres_add);
225
226static struct devres *find_dr(struct device *dev, dr_release_t release,
227 dr_match_t match, void *match_data)
228{
229 struct devres_node *node;
230
231 list_for_each_entry_reverse(node, &dev->devres_head, entry) {
232 struct devres *dr = container_of(node, struct devres, node);
233
234 if (node->release != release)
235 continue;
236 if (match && !match(dev, dr->data, match_data))
237 continue;
238 return dr;
239 }
240
241 return NULL;
242}
243
244/**
245 * devres_find - Find device resource
246 * @dev: Device to lookup resource from
247 * @release: Look for resources associated with this release function
248 * @match: Match function (optional)
249 * @match_data: Data for the match function
250 *
251 * Find the latest devres of @dev which is associated with @release
252 * and for which @match returns 1. If @match is NULL, it's considered
253 * to match all.
254 *
255 * RETURNS:
256 * Pointer to found devres, NULL if not found.
257 */
258void * devres_find(struct device *dev, dr_release_t release,
259 dr_match_t match, void *match_data)
260{
261 struct devres *dr;
262 unsigned long flags;
263
264 spin_lock_irqsave(&dev->devres_lock, flags);
265 dr = find_dr(dev, release, match, match_data);
266 spin_unlock_irqrestore(&dev->devres_lock, flags);
267
268 if (dr)
269 return dr->data;
270 return NULL;
271}
272EXPORT_SYMBOL_GPL(devres_find);
273
274/**
275 * devres_get - Find devres, if non-existent, add one atomically
276 * @dev: Device to lookup or add devres for
277 * @new_res: Pointer to new initialized devres to add if not found
278 * @match: Match function (optional)
279 * @match_data: Data for the match function
280 *
281 * Find the latest devres of @dev which has the same release function
282 * as @new_res and for which @match return 1. If found, @new_res is
283 * freed; otherwise, @new_res is added atomically.
284 *
285 * RETURNS:
286 * Pointer to found or added devres.
287 */
288void * devres_get(struct device *dev, void *new_res,
289 dr_match_t match, void *match_data)
290{
291 struct devres *new_dr = container_of(new_res, struct devres, data);
292 struct devres *dr;
293 unsigned long flags;
294
295 spin_lock_irqsave(&dev->devres_lock, flags);
296 dr = find_dr(dev, new_dr->node.release, match, match_data);
297 if (!dr) {
298 add_dr(dev, &new_dr->node);
299 dr = new_dr;
300 new_dr = NULL;
301 }
302 spin_unlock_irqrestore(&dev->devres_lock, flags);
303 devres_free(new_dr);
304
305 return dr->data;
306}
307EXPORT_SYMBOL_GPL(devres_get);
308
309/**
310 * devres_remove - Find a device resource and remove it
311 * @dev: Device to find resource from
312 * @release: Look for resources associated with this release function
313 * @match: Match function (optional)
314 * @match_data: Data for the match function
315 *
316 * Find the latest devres of @dev associated with @release and for
317 * which @match returns 1. If @match is NULL, it's considered to
318 * match all. If found, the resource is removed atomically and
319 * returned.
320 *
321 * RETURNS:
322 * Pointer to removed devres on success, NULL if not found.
323 */
324void * devres_remove(struct device *dev, dr_release_t release,
325 dr_match_t match, void *match_data)
326{
327 struct devres *dr;
328 unsigned long flags;
329
330 spin_lock_irqsave(&dev->devres_lock, flags);
331 dr = find_dr(dev, release, match, match_data);
332 if (dr) {
333 list_del_init(&dr->node.entry);
334 devres_log(dev, &dr->node, "REM");
335 }
336 spin_unlock_irqrestore(&dev->devres_lock, flags);
337
338 if (dr)
339 return dr->data;
340 return NULL;
341}
342EXPORT_SYMBOL_GPL(devres_remove);
343
344/**
345 * devres_destroy - Find a device resource and destroy it
346 * @dev: Device to find resource from
347 * @release: Look for resources associated with this release function
348 * @match: Match function (optional)
349 * @match_data: Data for the match function
350 *
351 * Find the latest devres of @dev associated with @release and for
352 * which @match returns 1. If @match is NULL, it's considered to
353 * match all. If found, the resource is removed atomically and freed.
354 *
355 * Note that the release function for the resource will not be called,
356 * only the devres-allocated data will be freed. The caller becomes
357 * responsible for freeing any other data.
358 *
359 * RETURNS:
360 * 0 if devres is found and freed, -ENOENT if not found.
361 */
362int devres_destroy(struct device *dev, dr_release_t release,
363 dr_match_t match, void *match_data)
364{
365 void *res;
366
367 res = devres_remove(dev, release, match, match_data);
368 if (unlikely(!res))
369 return -ENOENT;
370
371 devres_free(res);
372 return 0;
373}
374EXPORT_SYMBOL_GPL(devres_destroy);
375
376
377/**
378 * devres_release - Find a device resource and destroy it, calling release
379 * @dev: Device to find resource from
380 * @release: Look for resources associated with this release function
381 * @match: Match function (optional)
382 * @match_data: Data for the match function
383 *
384 * Find the latest devres of @dev associated with @release and for
385 * which @match returns 1. If @match is NULL, it's considered to
386 * match all. If found, the resource is removed atomically, the
387 * release function called and the resource freed.
388 *
389 * RETURNS:
390 * 0 if devres is found and freed, -ENOENT if not found.
391 */
392int devres_release(struct device *dev, dr_release_t release,
393 dr_match_t match, void *match_data)
394{
395 void *res;
396
397 res = devres_remove(dev, release, match, match_data);
398 if (unlikely(!res))
399 return -ENOENT;
400
401 (*release)(dev, res);
402 devres_free(res);
403 return 0;
404}
405EXPORT_SYMBOL_GPL(devres_release);
406
407static int remove_nodes(struct device *dev,
408 struct list_head *first, struct list_head *end,
409 struct list_head *todo)
410{
411 int cnt = 0, nr_groups = 0;
412 struct list_head *cur;
413
414 /* First pass - move normal devres entries to @todo and clear
415 * devres_group colors.
416 */
417 cur = first;
418 while (cur != end) {
419 struct devres_node *node;
420 struct devres_group *grp;
421
422 node = list_entry(cur, struct devres_node, entry);
423 cur = cur->next;
424
425 grp = node_to_group(node);
426 if (grp) {
427 /* clear color of group markers in the first pass */
428 grp->color = 0;
429 nr_groups++;
430 } else {
431 /* regular devres entry */
432 if (&node->entry == first)
433 first = first->next;
434 list_move_tail(&node->entry, todo);
435 cnt++;
436 }
437 }
438
439 if (!nr_groups)
440 return cnt;
441
442 /* Second pass - Scan groups and color them. A group gets
443 * color value of two iff the group is wholly contained in
444 * [cur, end). That is, for a closed group, both opening and
445 * closing markers should be in the range, while just the
446 * opening marker is enough for an open group.
447 */
448 cur = first;
449 while (cur != end) {
450 struct devres_node *node;
451 struct devres_group *grp;
452
453 node = list_entry(cur, struct devres_node, entry);
454 cur = cur->next;
455
456 grp = node_to_group(node);
457 BUG_ON(!grp || list_empty(&grp->node[0].entry));
458
459 grp->color++;
460 if (list_empty(&grp->node[1].entry))
461 grp->color++;
462
463 BUG_ON(grp->color <= 0 || grp->color > 2);
464 if (grp->color == 2) {
465 /* No need to update cur or end. The removed
466 * nodes are always before both.
467 */
468 list_move_tail(&grp->node[0].entry, todo);
469 list_del_init(&grp->node[1].entry);
470 }
471 }
472
473 return cnt;
474}
475
476static int release_nodes(struct device *dev, struct list_head *first,
477 struct list_head *end, unsigned long flags)
478 __releases(&dev->devres_lock)
479{
480 LIST_HEAD(todo);
481 int cnt;
482 struct devres *dr, *tmp;
483
484 cnt = remove_nodes(dev, first, end, &todo);
485
486 spin_unlock_irqrestore(&dev->devres_lock, flags);
487
488 /* Release. Note that both devres and devres_group are
489 * handled as devres in the following loop. This is safe.
490 */
491 list_for_each_entry_safe_reverse(dr, tmp, &todo, node.entry) {
492 devres_log(dev, &dr->node, "REL");
493 dr->node.release(dev, dr->data);
494 kfree(dr);
495 }
496
497 return cnt;
498}
499
500/**
501 * devres_release_all - Release all managed resources
502 * @dev: Device to release resources for
503 *
504 * Release all resources associated with @dev. This function is
505 * called on driver detach.
506 */
507int devres_release_all(struct device *dev)
508{
509 unsigned long flags;
510
511 /* Looks like an uninitialized device structure */
512 if (WARN_ON(dev->devres_head.next == NULL))
513 return -ENODEV;
514 spin_lock_irqsave(&dev->devres_lock, flags);
515 return release_nodes(dev, dev->devres_head.next, &dev->devres_head,
516 flags);
517}
518
519/**
520 * devres_open_group - Open a new devres group
521 * @dev: Device to open devres group for
522 * @id: Separator ID
523 * @gfp: Allocation flags
524 *
525 * Open a new devres group for @dev with @id. For @id, using a
526 * pointer to an object which won't be used for another group is
527 * recommended. If @id is NULL, address-wise unique ID is created.
528 *
529 * RETURNS:
530 * ID of the new group, NULL on failure.
531 */
532void * devres_open_group(struct device *dev, void *id, gfp_t gfp)
533{
534 struct devres_group *grp;
535 unsigned long flags;
536
537 grp = kmalloc(sizeof(*grp), gfp);
538 if (unlikely(!grp))
539 return NULL;
540
541 grp->node[0].release = &group_open_release;
542 grp->node[1].release = &group_close_release;
543 INIT_LIST_HEAD(&grp->node[0].entry);
544 INIT_LIST_HEAD(&grp->node[1].entry);
545 set_node_dbginfo(&grp->node[0], "grp<", 0);
546 set_node_dbginfo(&grp->node[1], "grp>", 0);
547 grp->id = grp;
548 if (id)
549 grp->id = id;
550
551 spin_lock_irqsave(&dev->devres_lock, flags);
552 add_dr(dev, &grp->node[0]);
553 spin_unlock_irqrestore(&dev->devres_lock, flags);
554 return grp->id;
555}
556EXPORT_SYMBOL_GPL(devres_open_group);
557
558/* Find devres group with ID @id. If @id is NULL, look for the latest. */
559static struct devres_group * find_group(struct device *dev, void *id)
560{
561 struct devres_node *node;
562
563 list_for_each_entry_reverse(node, &dev->devres_head, entry) {
564 struct devres_group *grp;
565
566 if (node->release != &group_open_release)
567 continue;
568
569 grp = container_of(node, struct devres_group, node[0]);
570
571 if (id) {
572 if (grp->id == id)
573 return grp;
574 } else if (list_empty(&grp->node[1].entry))
575 return grp;
576 }
577
578 return NULL;
579}
580
581/**
582 * devres_close_group - Close a devres group
583 * @dev: Device to close devres group for
584 * @id: ID of target group, can be NULL
585 *
586 * Close the group identified by @id. If @id is NULL, the latest open
587 * group is selected.
588 */
589void devres_close_group(struct device *dev, void *id)
590{
591 struct devres_group *grp;
592 unsigned long flags;
593
594 spin_lock_irqsave(&dev->devres_lock, flags);
595
596 grp = find_group(dev, id);
597 if (grp)
598 add_dr(dev, &grp->node[1]);
599 else
600 WARN_ON(1);
601
602 spin_unlock_irqrestore(&dev->devres_lock, flags);
603}
604EXPORT_SYMBOL_GPL(devres_close_group);
605
606/**
607 * devres_remove_group - Remove a devres group
608 * @dev: Device to remove group for
609 * @id: ID of target group, can be NULL
610 *
611 * Remove the group identified by @id. If @id is NULL, the latest
612 * open group is selected. Note that removing a group doesn't affect
613 * any other resources.
614 */
615void devres_remove_group(struct device *dev, void *id)
616{
617 struct devres_group *grp;
618 unsigned long flags;
619
620 spin_lock_irqsave(&dev->devres_lock, flags);
621
622 grp = find_group(dev, id);
623 if (grp) {
624 list_del_init(&grp->node[0].entry);
625 list_del_init(&grp->node[1].entry);
626 devres_log(dev, &grp->node[0], "REM");
627 } else
628 WARN_ON(1);
629
630 spin_unlock_irqrestore(&dev->devres_lock, flags);
631
632 kfree(grp);
633}
634EXPORT_SYMBOL_GPL(devres_remove_group);
635
636/**
637 * devres_release_group - Release resources in a devres group
638 * @dev: Device to release group for
639 * @id: ID of target group, can be NULL
640 *
641 * Release all resources in the group identified by @id. If @id is
642 * NULL, the latest open group is selected. The selected group and
643 * groups properly nested inside the selected group are removed.
644 *
645 * RETURNS:
646 * The number of released non-group resources.
647 */
648int devres_release_group(struct device *dev, void *id)
649{
650 struct devres_group *grp;
651 unsigned long flags;
652 int cnt = 0;
653
654 spin_lock_irqsave(&dev->devres_lock, flags);
655
656 grp = find_group(dev, id);
657 if (grp) {
658 struct list_head *first = &grp->node[0].entry;
659 struct list_head *end = &dev->devres_head;
660
661 if (!list_empty(&grp->node[1].entry))
662 end = grp->node[1].entry.next;
663
664 cnt = release_nodes(dev, first, end, flags);
665 } else {
666 WARN_ON(1);
667 spin_unlock_irqrestore(&dev->devres_lock, flags);
668 }
669
670 return cnt;
671}
672EXPORT_SYMBOL_GPL(devres_release_group);
673
674/*
675 * Custom devres actions allow inserting a simple function call
676 * into the teadown sequence.
677 */
678
679struct action_devres {
680 void *data;
681 void (*action)(void *);
682};
683
684static int devm_action_match(struct device *dev, void *res, void *p)
685{
686 struct action_devres *devres = res;
687 struct action_devres *target = p;
688
689 return devres->action == target->action &&
690 devres->data == target->data;
691}
692
693static void devm_action_release(struct device *dev, void *res)
694{
695 struct action_devres *devres = res;
696
697 devres->action(devres->data);
698}
699
700/**
701 * devm_add_action() - add a custom action to list of managed resources
702 * @dev: Device that owns the action
703 * @action: Function that should be called
704 * @data: Pointer to data passed to @action implementation
705 *
706 * This adds a custom action to the list of managed resources so that
707 * it gets executed as part of standard resource unwinding.
708 */
709int devm_add_action(struct device *dev, void (*action)(void *), void *data)
710{
711 struct action_devres *devres;
712
713 devres = devres_alloc(devm_action_release,
714 sizeof(struct action_devres), GFP_KERNEL);
715 if (!devres)
716 return -ENOMEM;
717
718 devres->data = data;
719 devres->action = action;
720
721 devres_add(dev, devres);
722 return 0;
723}
724EXPORT_SYMBOL_GPL(devm_add_action);
725
726/**
727 * devm_remove_action() - removes previously added custom action
728 * @dev: Device that owns the action
729 * @action: Function implementing the action
730 * @data: Pointer to data passed to @action implementation
731 *
732 * Removes instance of @action previously added by devm_add_action().
733 * Both action and data should match one of the existing entries.
734 */
735void devm_remove_action(struct device *dev, void (*action)(void *), void *data)
736{
737 struct action_devres devres = {
738 .data = data,
739 .action = action,
740 };
741
742 WARN_ON(devres_destroy(dev, devm_action_release, devm_action_match,
743 &devres));
744
745}
746EXPORT_SYMBOL_GPL(devm_remove_action);
747
748/*
749 * Managed kmalloc/kfree
750 */
751static void devm_kmalloc_release(struct device *dev, void *res)
752{
753 /* noop */
754}
755
756static int devm_kmalloc_match(struct device *dev, void *res, void *data)
757{
758 return res == data;
759}
760
761/**
762 * devm_kmalloc - Resource-managed kmalloc
763 * @dev: Device to allocate memory for
764 * @size: Allocation size
765 * @gfp: Allocation gfp flags
766 *
767 * Managed kmalloc. Memory allocated with this function is
768 * automatically freed on driver detach. Like all other devres
769 * resources, guaranteed alignment is unsigned long long.
770 *
771 * RETURNS:
772 * Pointer to allocated memory on success, NULL on failure.
773 */
774void * devm_kmalloc(struct device *dev, size_t size, gfp_t gfp)
775{
776 struct devres *dr;
777
778 /* use raw alloc_dr for kmalloc caller tracing */
779 dr = alloc_dr(devm_kmalloc_release, size, gfp);
780 if (unlikely(!dr))
781 return NULL;
782
783 /*
784 * This is named devm_kzalloc_release for historical reasons
785 * The initial implementation did not support kmalloc, only kzalloc
786 */
787 set_node_dbginfo(&dr->node, "devm_kzalloc_release", size);
788 devres_add(dev, dr->data);
789 return dr->data;
790}
791EXPORT_SYMBOL_GPL(devm_kmalloc);
792
793/**
794 * devm_kfree - Resource-managed kfree
795 * @dev: Device this memory belongs to
796 * @p: Memory to free
797 *
798 * Free memory allocated with devm_kmalloc().
799 */
800void devm_kfree(struct device *dev, void *p)
801{
802 int rc;
803
804 rc = devres_destroy(dev, devm_kmalloc_release, devm_kmalloc_match, p);
805 WARN_ON(rc);
806}
807EXPORT_SYMBOL_GPL(devm_kfree);