projects/linux·blob v2.6.36 · 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_printk(KERN_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, tot_size);
95 INIT_LIST_HEAD(&dr->node.entry);
96 dr->node.release = release;
97 return dr;
98}
99
100static void add_dr(struct device *dev, struct devres_node *node)
101{
102 devres_log(dev, node, "ADD");
103 BUG_ON(!list_empty(&node->entry));
104 list_add_tail(&node->entry, &dev->devres_head);
105}
106
107#ifdef CONFIG_DEBUG_DEVRES
108void * __devres_alloc(dr_release_t release, size_t size, gfp_t gfp,
109 const char *name)
110{
111 struct devres *dr;
112
113 dr = alloc_dr(release, size, gfp);
114 if (unlikely(!dr))
115 return NULL;
116 set_node_dbginfo(&dr->node, name, size);
117 return dr->data;
118}
119EXPORT_SYMBOL_GPL(__devres_alloc);
120#else
121/**
122 * devres_alloc - Allocate device resource data
123 * @release: Release function devres will be associated with
124 * @size: Allocation size
125 * @gfp: Allocation flags
126 *
127 * Allocate devres of @size bytes. The allocated area is zeroed, then
128 * associated with @release. The returned pointer can be passed to
129 * other devres_*() functions.
130 *
131 * RETURNS:
132 * Pointer to allocated devres on success, NULL on failure.
133 */
134void * devres_alloc(dr_release_t release, size_t size, gfp_t gfp)
135{
136 struct devres *dr;
137
138 dr = alloc_dr(release, size, gfp);
139 if (unlikely(!dr))
140 return NULL;
141 return dr->data;
142}
143EXPORT_SYMBOL_GPL(devres_alloc);
144#endif
145
146/**
147 * devres_free - Free device resource data
148 * @res: Pointer to devres data to free
149 *
150 * Free devres created with devres_alloc().
151 */
152void devres_free(void *res)
153{
154 if (res) {
155 struct devres *dr = container_of(res, struct devres, data);
156
157 BUG_ON(!list_empty(&dr->node.entry));
158 kfree(dr);
159 }
160}
161EXPORT_SYMBOL_GPL(devres_free);
162
163/**
164 * devres_add - Register device resource
165 * @dev: Device to add resource to
166 * @res: Resource to register
167 *
168 * Register devres @res to @dev. @res should have been allocated
169 * using devres_alloc(). On driver detach, the associated release
170 * function will be invoked and devres will be freed automatically.
171 */
172void devres_add(struct device *dev, void *res)
173{
174 struct devres *dr = container_of(res, struct devres, data);
175 unsigned long flags;
176
177 spin_lock_irqsave(&dev->devres_lock, flags);
178 add_dr(dev, &dr->node);
179 spin_unlock_irqrestore(&dev->devres_lock, flags);
180}
181EXPORT_SYMBOL_GPL(devres_add);
182
183static struct devres *find_dr(struct device *dev, dr_release_t release,
184 dr_match_t match, void *match_data)
185{
186 struct devres_node *node;
187
188 list_for_each_entry_reverse(node, &dev->devres_head, entry) {
189 struct devres *dr = container_of(node, struct devres, node);
190
191 if (node->release != release)
192 continue;
193 if (match && !match(dev, dr->data, match_data))
194 continue;
195 return dr;
196 }
197
198 return NULL;
199}
200
201/**
202 * devres_find - Find device resource
203 * @dev: Device to lookup resource from
204 * @release: Look for resources associated with this release function
205 * @match: Match function (optional)
206 * @match_data: Data for the match function
207 *
208 * Find the latest devres of @dev which is associated with @release
209 * and for which @match returns 1. If @match is NULL, it's considered
210 * to match all.
211 *
212 * RETURNS:
213 * Pointer to found devres, NULL if not found.
214 */
215void * devres_find(struct device *dev, dr_release_t release,
216 dr_match_t match, void *match_data)
217{
218 struct devres *dr;
219 unsigned long flags;
220
221 spin_lock_irqsave(&dev->devres_lock, flags);
222 dr = find_dr(dev, release, match, match_data);
223 spin_unlock_irqrestore(&dev->devres_lock, flags);
224
225 if (dr)
226 return dr->data;
227 return NULL;
228}
229EXPORT_SYMBOL_GPL(devres_find);
230
231/**
232 * devres_get - Find devres, if non-existent, add one atomically
233 * @dev: Device to lookup or add devres for
234 * @new_res: Pointer to new initialized devres to add if not found
235 * @match: Match function (optional)
236 * @match_data: Data for the match function
237 *
238 * Find the latest devres of @dev which has the same release function
239 * as @new_res and for which @match return 1. If found, @new_res is
240 * freed; otherwise, @new_res is added atomically.
241 *
242 * RETURNS:
243 * Pointer to found or added devres.
244 */
245void * devres_get(struct device *dev, void *new_res,
246 dr_match_t match, void *match_data)
247{
248 struct devres *new_dr = container_of(new_res, struct devres, data);
249 struct devres *dr;
250 unsigned long flags;
251
252 spin_lock_irqsave(&dev->devres_lock, flags);
253 dr = find_dr(dev, new_dr->node.release, match, match_data);
254 if (!dr) {
255 add_dr(dev, &new_dr->node);
256 dr = new_dr;
257 new_dr = NULL;
258 }
259 spin_unlock_irqrestore(&dev->devres_lock, flags);
260 devres_free(new_dr);
261
262 return dr->data;
263}
264EXPORT_SYMBOL_GPL(devres_get);
265
266/**
267 * devres_remove - Find a device resource and remove it
268 * @dev: Device to find resource from
269 * @release: Look for resources associated with this release function
270 * @match: Match function (optional)
271 * @match_data: Data for the match function
272 *
273 * Find the latest devres of @dev associated with @release and for
274 * which @match returns 1. If @match is NULL, it's considered to
275 * match all. If found, the resource is removed atomically and
276 * returned.
277 *
278 * RETURNS:
279 * Pointer to removed devres on success, NULL if not found.
280 */
281void * devres_remove(struct device *dev, dr_release_t release,
282 dr_match_t match, void *match_data)
283{
284 struct devres *dr;
285 unsigned long flags;
286
287 spin_lock_irqsave(&dev->devres_lock, flags);
288 dr = find_dr(dev, release, match, match_data);
289 if (dr) {
290 list_del_init(&dr->node.entry);
291 devres_log(dev, &dr->node, "REM");
292 }
293 spin_unlock_irqrestore(&dev->devres_lock, flags);
294
295 if (dr)
296 return dr->data;
297 return NULL;
298}
299EXPORT_SYMBOL_GPL(devres_remove);
300
301/**
302 * devres_destroy - Find a device resource and destroy it
303 * @dev: Device to find resource from
304 * @release: Look for resources associated with this release function
305 * @match: Match function (optional)
306 * @match_data: Data for the match function
307 *
308 * Find the latest devres of @dev associated with @release and for
309 * which @match returns 1. If @match is NULL, it's considered to
310 * match all. If found, the resource is removed atomically and freed.
311 *
312 * RETURNS:
313 * 0 if devres is found and freed, -ENOENT if not found.
314 */
315int devres_destroy(struct device *dev, dr_release_t release,
316 dr_match_t match, void *match_data)
317{
318 void *res;
319
320 res = devres_remove(dev, release, match, match_data);
321 if (unlikely(!res))
322 return -ENOENT;
323
324 devres_free(res);
325 return 0;
326}
327EXPORT_SYMBOL_GPL(devres_destroy);
328
329static int remove_nodes(struct device *dev,
330 struct list_head *first, struct list_head *end,
331 struct list_head *todo)
332{
333 int cnt = 0, nr_groups = 0;
334 struct list_head *cur;
335
336 /* First pass - move normal devres entries to @todo and clear
337 * devres_group colors.
338 */
339 cur = first;
340 while (cur != end) {
341 struct devres_node *node;
342 struct devres_group *grp;
343
344 node = list_entry(cur, struct devres_node, entry);
345 cur = cur->next;
346
347 grp = node_to_group(node);
348 if (grp) {
349 /* clear color of group markers in the first pass */
350 grp->color = 0;
351 nr_groups++;
352 } else {
353 /* regular devres entry */
354 if (&node->entry == first)
355 first = first->next;
356 list_move_tail(&node->entry, todo);
357 cnt++;
358 }
359 }
360
361 if (!nr_groups)
362 return cnt;
363
364 /* Second pass - Scan groups and color them. A group gets
365 * color value of two iff the group is wholly contained in
366 * [cur, end). That is, for a closed group, both opening and
367 * closing markers should be in the range, while just the
368 * opening marker is enough for an open group.
369 */
370 cur = first;
371 while (cur != end) {
372 struct devres_node *node;
373 struct devres_group *grp;
374
375 node = list_entry(cur, struct devres_node, entry);
376 cur = cur->next;
377
378 grp = node_to_group(node);
379 BUG_ON(!grp || list_empty(&grp->node[0].entry));
380
381 grp->color++;
382 if (list_empty(&grp->node[1].entry))
383 grp->color++;
384
385 BUG_ON(grp->color <= 0 || grp->color > 2);
386 if (grp->color == 2) {
387 /* No need to update cur or end. The removed
388 * nodes are always before both.
389 */
390 list_move_tail(&grp->node[0].entry, todo);
391 list_del_init(&grp->node[1].entry);
392 }
393 }
394
395 return cnt;
396}
397
398static int release_nodes(struct device *dev, struct list_head *first,
399 struct list_head *end, unsigned long flags)
400{
401 LIST_HEAD(todo);
402 int cnt;
403 struct devres *dr, *tmp;
404
405 cnt = remove_nodes(dev, first, end, &todo);
406
407 spin_unlock_irqrestore(&dev->devres_lock, flags);
408
409 /* Release. Note that both devres and devres_group are
410 * handled as devres in the following loop. This is safe.
411 */
412 list_for_each_entry_safe_reverse(dr, tmp, &todo, node.entry) {
413 devres_log(dev, &dr->node, "REL");
414 dr->node.release(dev, dr->data);
415 kfree(dr);
416 }
417
418 return cnt;
419}
420
421/**
422 * devres_release_all - Release all managed resources
423 * @dev: Device to release resources for
424 *
425 * Release all resources associated with @dev. This function is
426 * called on driver detach.
427 */
428int devres_release_all(struct device *dev)
429{
430 unsigned long flags;
431
432 /* Looks like an uninitialized device structure */
433 if (WARN_ON(dev->devres_head.next == NULL))
434 return -ENODEV;
435 spin_lock_irqsave(&dev->devres_lock, flags);
436 return release_nodes(dev, dev->devres_head.next, &dev->devres_head,
437 flags);
438}
439
440/**
441 * devres_open_group - Open a new devres group
442 * @dev: Device to open devres group for
443 * @id: Separator ID
444 * @gfp: Allocation flags
445 *
446 * Open a new devres group for @dev with @id. For @id, using a
447 * pointer to an object which won't be used for another group is
448 * recommended. If @id is NULL, address-wise unique ID is created.
449 *
450 * RETURNS:
451 * ID of the new group, NULL on failure.
452 */
453void * devres_open_group(struct device *dev, void *id, gfp_t gfp)
454{
455 struct devres_group *grp;
456 unsigned long flags;
457
458 grp = kmalloc(sizeof(*grp), gfp);
459 if (unlikely(!grp))
460 return NULL;
461
462 grp->node[0].release = &group_open_release;
463 grp->node[1].release = &group_close_release;
464 INIT_LIST_HEAD(&grp->node[0].entry);
465 INIT_LIST_HEAD(&grp->node[1].entry);
466 set_node_dbginfo(&grp->node[0], "grp<", 0);
467 set_node_dbginfo(&grp->node[1], "grp>", 0);
468 grp->id = grp;
469 if (id)
470 grp->id = id;
471
472 spin_lock_irqsave(&dev->devres_lock, flags);
473 add_dr(dev, &grp->node[0]);
474 spin_unlock_irqrestore(&dev->devres_lock, flags);
475 return grp->id;
476}
477EXPORT_SYMBOL_GPL(devres_open_group);
478
479/* Find devres group with ID @id. If @id is NULL, look for the latest. */
480static struct devres_group * find_group(struct device *dev, void *id)
481{
482 struct devres_node *node;
483
484 list_for_each_entry_reverse(node, &dev->devres_head, entry) {
485 struct devres_group *grp;
486
487 if (node->release != &group_open_release)
488 continue;
489
490 grp = container_of(node, struct devres_group, node[0]);
491
492 if (id) {
493 if (grp->id == id)
494 return grp;
495 } else if (list_empty(&grp->node[1].entry))
496 return grp;
497 }
498
499 return NULL;
500}
501
502/**
503 * devres_close_group - Close a devres group
504 * @dev: Device to close devres group for
505 * @id: ID of target group, can be NULL
506 *
507 * Close the group identified by @id. If @id is NULL, the latest open
508 * group is selected.
509 */
510void devres_close_group(struct device *dev, void *id)
511{
512 struct devres_group *grp;
513 unsigned long flags;
514
515 spin_lock_irqsave(&dev->devres_lock, flags);
516
517 grp = find_group(dev, id);
518 if (grp)
519 add_dr(dev, &grp->node[1]);
520 else
521 WARN_ON(1);
522
523 spin_unlock_irqrestore(&dev->devres_lock, flags);
524}
525EXPORT_SYMBOL_GPL(devres_close_group);
526
527/**
528 * devres_remove_group - Remove a devres group
529 * @dev: Device to remove group for
530 * @id: ID of target group, can be NULL
531 *
532 * Remove the group identified by @id. If @id is NULL, the latest
533 * open group is selected. Note that removing a group doesn't affect
534 * any other resources.
535 */
536void devres_remove_group(struct device *dev, void *id)
537{
538 struct devres_group *grp;
539 unsigned long flags;
540
541 spin_lock_irqsave(&dev->devres_lock, flags);
542
543 grp = find_group(dev, id);
544 if (grp) {
545 list_del_init(&grp->node[0].entry);
546 list_del_init(&grp->node[1].entry);
547 devres_log(dev, &grp->node[0], "REM");
548 } else
549 WARN_ON(1);
550
551 spin_unlock_irqrestore(&dev->devres_lock, flags);
552
553 kfree(grp);
554}
555EXPORT_SYMBOL_GPL(devres_remove_group);
556
557/**
558 * devres_release_group - Release resources in a devres group
559 * @dev: Device to release group for
560 * @id: ID of target group, can be NULL
561 *
562 * Release all resources in the group identified by @id. If @id is
563 * NULL, the latest open group is selected. The selected group and
564 * groups properly nested inside the selected group are removed.
565 *
566 * RETURNS:
567 * The number of released non-group resources.
568 */
569int devres_release_group(struct device *dev, void *id)
570{
571 struct devres_group *grp;
572 unsigned long flags;
573 int cnt = 0;
574
575 spin_lock_irqsave(&dev->devres_lock, flags);
576
577 grp = find_group(dev, id);
578 if (grp) {
579 struct list_head *first = &grp->node[0].entry;
580 struct list_head *end = &dev->devres_head;
581
582 if (!list_empty(&grp->node[1].entry))
583 end = grp->node[1].entry.next;
584
585 cnt = release_nodes(dev, first, end, flags);
586 } else {
587 WARN_ON(1);
588 spin_unlock_irqrestore(&dev->devres_lock, flags);
589 }
590
591 return cnt;
592}
593EXPORT_SYMBOL_GPL(devres_release_group);
594
595/*
596 * Managed kzalloc/kfree
597 */
598static void devm_kzalloc_release(struct device *dev, void *res)
599{
600 /* noop */
601}
602
603static int devm_kzalloc_match(struct device *dev, void *res, void *data)
604{
605 return res == data;
606}
607
608/**
609 * devm_kzalloc - Resource-managed kzalloc
610 * @dev: Device to allocate memory for
611 * @size: Allocation size
612 * @gfp: Allocation gfp flags
613 *
614 * Managed kzalloc. Memory allocated with this function is
615 * automatically freed on driver detach. Like all other devres
616 * resources, guaranteed alignment is unsigned long long.
617 *
618 * RETURNS:
619 * Pointer to allocated memory on success, NULL on failure.
620 */
621void * devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
622{
623 struct devres *dr;
624
625 /* use raw alloc_dr for kmalloc caller tracing */
626 dr = alloc_dr(devm_kzalloc_release, size, gfp);
627 if (unlikely(!dr))
628 return NULL;
629
630 set_node_dbginfo(&dr->node, "devm_kzalloc_release", size);
631 devres_add(dev, dr->data);
632 return dr->data;
633}
634EXPORT_SYMBOL_GPL(devm_kzalloc);
635
636/**
637 * devm_kfree - Resource-managed kfree
638 * @dev: Device this memory belongs to
639 * @p: Memory to free
640 *
641 * Free memory allocated with dev_kzalloc().
642 */
643void devm_kfree(struct device *dev, void *p)
644{
645 int rc;
646
647 rc = devres_destroy(dev, devm_kzalloc_release, devm_kzalloc_match, p);
648 WARN_ON(rc);
649}
650EXPORT_SYMBOL_GPL(devm_kfree);