aboutsummaryrefslogtreecommitdiff
path: root/drivers/base/devres.c
blob: 6683906647640da75238198ac47a07561fd131f9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
/*
 * drivers/base/devres.c - device resource management
 *
 * Copyright (c) 2006  SUSE Linux Products GmbH
 * Copyright (c) 2006  Tejun Heo <teheo@suse.de>
 *
 * This file is released under the GPLv2.
 */

#include <linux/device.h>
#include <linux/module.h>
#include <linux/slab.h>

#include "base.h"

struct devres_node {
	struct list_head		entry;
	dr_release_t			release;
#ifdef CONFIG_DEBUG_DEVRES
	const char			*name;
	size_t				size;
#endif
};

struct devres {
	struct devres_node		node;
	/* -- 3 pointers */
	unsigned long long		data[];	/* guarantee ull alignment */
};

struct devres_group {
	struct devres_node		node[2];
	void				*id;
	int				color;
	/* -- 8 pointers */
};

#ifdef CONFIG_DEBUG_DEVRES
static int log_devres = 0;
module_param_named(log, log_devres, int, S_IRUGO | S_IWUSR);

static void set_node_dbginfo(struct devres_node *node, const char *name,
			     size_t size)
{
	node->name = name;
	node->size = size;
}

static void devres_log(struct device *dev, struct devres_node *node,
		       const char *op)
{
	if (unlikely(log_devres))
		dev_err(dev, "DEVRES %3s %p %s (%lu bytes)\n",
			op, node, node->name, (unsigned long)node->size);
}
#else /* CONFIG_DEBUG_DEVRES */
#define set_node_dbginfo(node, n, s)	do {} while (0)
#define devres_log(dev, node, op)	do {} while (0)
#endif /* CONFIG_DEBUG_DEVRES */

/*
 * Release functions for devres group.  These callbacks are used only
 * for identification.
 */
static void group_open_release(struct device *dev, void *res)
{
	/* noop */
}

static void group_close_release(struct device *dev, void *res)
{
	/* noop */
}

static struct devres_group * node_to_group(struct devres_node *node)
{
	if (node->release == &group_open_release)
		return container_of(node, struct devres_group, node[0]);
	if (node->release == &group_close_release)
		return container_of(node, struct devres_group, node[1]);
	return NULL;
}

static __always_inline struct devres * alloc_dr(dr_release_t release,
						size_t size, gfp_t gfp)
{
	size_t tot_size = sizeof(struct devres) + size;
	struct devres *dr;

	dr = kmalloc_track_caller(tot_size, gfp);
	if (unlikely(!dr))
		return NULL;

	memset(dr, 0, tot_size);
	INIT_LIST_HEAD(&dr->node.entry);
	dr->node.release = release;
	return dr;
}

static void add_dr(struct device *dev, struct devres_node *node)
{
	devres_log(dev, node, "ADD");
	BUG_ON(!list_empty(&node->entry));
	list_add_tail(&node->entry, &dev->devres_head);
}

#ifdef CONFIG_DEBUG_DEVRES
void * __devres_alloc(dr_release_t release, size_t size, gfp_t gfp,
		      const char *name)
{
	struct devres *dr;

	dr = alloc_dr(release, size, gfp);
	if (unlikely(!dr))
		return NULL;
	set_node_dbginfo(&dr->node, name, size);
	return dr->data;
}
EXPORT_SYMBOL_GPL(__devres_alloc);
#else
/**
 * devres_alloc - Allocate device resource data
 * @release: Release function devres will be associated with
 * @size: Allocation size
 * @gfp: Allocation flags
 *
 * Allocate devres of @size bytes.  The allocated area is zeroed, then
 * associated with @release.  The returned pointer can be passed to
 * other devres_*() functions.
 *
 * RETURNS:
 * Pointer to allocated devres on success, NULL on failure.
 */
void * devres_alloc(dr_release_t release, size_t size, gfp_t gfp)
{
	struct devres *dr;

	dr = alloc_dr(release, size, gfp);
	if (unlikely(!dr))
		return NULL;
	return dr->data;
}
EXPORT_SYMBOL_GPL(devres_alloc);
#endif

/**
 * devres_for_each_res - Resource iterator
 * @dev: Device to iterate resource from
 * @release: Look for resources associated with this release function
 * @match: Match function (optional)
 * @match_data: Data for the match function
 * @fn: Function to be called for each matched resource.
 * @data: Data for @fn, the 3rd parameter of @fn
 *
 * Call @fn for each devres of @dev which is associated with @release
 * and for which @match returns 1.
 *
 * RETURNS:
 * 	void
 */
void devres_for_each_res(struct device *dev, dr_release_t release,
			dr_match_t match, void *match_data,
			void (*fn)(struct device *, void *, void *),
			void *data)
{
	struct devres_node *node;
	struct devres_node *tmp;
	unsigned long flags;

	if (!fn)
		return;

	spin_lock_irqsave(&dev->devres_lock, flags);
	list_for_each_entry_safe_reverse(node, tmp,
			&dev->devres_head, entry) {
		struct devres *dr = container_of(node, struct devres, node);

		if (node->release != release)
			continue;
		if (match && !match(dev, dr->data, match_data))
			continue;
		fn(dev, dr->data, data);
	}
	spin_unlock_irqrestore(&dev->devres_lock, flags);
}
EXPORT_SYMBOL_GPL(devres_for_each_res);

/**
 * devres_free - Free device resource data
 * @res: Pointer to devres data to free
 *
 * Free devres created with devres_alloc().
 */
void devres_free(void *res)
{
	if (res) {
		struct devres *dr = container_of(res, struct devres, data);

		BUG_ON(!list_empty(&dr->node.entry));
		kfree(dr);
	}
}
EXPORT_SYMBOL_GPL(devres_free);

/**
 * devres_add - Register device resource
 * @dev: Device to add resource to
 * @res: Resource to register
 *
 * Register devres @res to @dev.  @res should have been allocated
 * using devres_alloc().  On driver detach, the associated release
 * function will be invoked and devres will be freed automatically.
 */
void devres_add(struct device *dev, void *res)
{
	struct devres *dr = container_of(res, struct devres, data);
	unsigned long flags;

	spin_lock_irqsave(&dev->devres_lock, flags);
	add_dr(dev, &dr->node);
	spin_unlock_irqrestore(&dev->devres_lock, flags);
}
EXPORT_SYMBOL_GPL(devres_add);

static struct devres *find_dr(struct device *dev, dr_release_t release,
			      dr_match_t match, void *match_data)
{
	struct devres_node *node;

	list_for_each_entry_reverse(node, &dev->devres_head, entry) {
		struct devres *dr = container_of(node, struct devres, node);

		if (node->release != release)
			continue;
		if (match && !match(dev, dr->data, match_data))
			continue;
		return dr;
	}

	return NULL;
}

/**
 * devres_find - Find device resource
 * @dev: Device to lookup resource from
 * @release: Look for resources associated with this release function
 * @match: Match function (optional)
 * @match_data: Data for the match function
 *
 * Find the latest devres of @dev which is associated with @release
 * and for which @match returns 1.  If @match is NULL, it's considered
 * to match all.
 *
 * RETURNS:
 * Pointer to found devres, NULL if not found.
 */
void * devres_find(struct device *dev, dr_release_t release,
		   dr_match_t match, void *match_data)
{
	struct devres *dr;
	unsigned long flags;

	spin_lock_irqsave(&dev->devres_lock, flags);
	dr = find_dr(dev, release, match, match_data);
	spin_unlock_irqrestore(&dev->devres_lock, flags);

	if (dr)
		return dr->data;
	return NULL;
}
EXPORT_SYMBOL_GPL(devres_find);

/**
 * devres_get - Find devres, if non-existent, add one atomically
 * @dev: Device to lookup or add devres for
 * @new_res: Pointer to new initialized devres to add if not found
 * @match: Match function (optional)
 * @match_data: Data for the match function
 *
 * Find the latest devres of @dev which has the same release function
 * as @new_res and for which @match return 1.  If found, @new_res is
 * freed; otherwise, @new_res is added atomically.
 *
 * RETURNS:
 * Pointer to found or added devres.
 */
void * devres_get(struct device *dev, void *new_res,
		  dr_match_t match, void *match_data)
{
	struct devres *new_dr = container_of(new_res, struct devres, data);
	struct devres *dr;
	unsigned long flags;

	spin_lock_irqsave(&dev->devres_lock, flags);
	dr = find_dr(dev, new_dr->node.release, match, match_data);
	if (!dr) {
		add_dr(dev, &new_dr->node);
		dr = new_dr;
		new_dr = NULL;
	}
	spin_unlock_irqrestore(&dev->devres_lock, flags);
	devres_free(new_dr);

	return dr->data;
}
EXPORT_SYMBOL_GPL(devres_get);

/**
 * devres_remove - Find a device resource and remove it
 * @dev: Device to find resource from
 * @release: Look for resources associated with this release function
 * @match: Match function (optional)
 * @match_data: Data for the match function
 *
 * Find the latest devres of @dev associated with @release and for
 * which @match returns 1.  If @match is NULL, it's considered to
 * match all.  If found, the resource is removed atomically and
 * returned.
 *
 * RETURNS:
 * Pointer to removed devres on success, NULL if not found.
 */
void * devres_remove(struct device *dev, dr_release_t release,
		     dr_match_t match, void *match_data)
{
	struct devres *dr;
	unsigned long flags;

	spin_lock_irqsave(&dev->devres_lock, flags);
	dr = find_dr(dev, release, match, match_data);
	if (dr) {
		list_del_init(&dr->node.entry);
		devres_log(dev, &dr->node, "REM");
	}
	spin_unlock_irqrestore(&dev->devres_lock, flags);

	if (dr)
		return dr->data;
	return NULL;
}
EXPORT_SYMBOL_GPL(devres_remove);

/**
 * devres_destroy - Find a device resource and destroy it
 * @dev: Device to find resource from
 * @release: Look for resources associated with this release function
 * @match: Match function (optional)
 * @match_data: Data for the match function
 *
 * Find the latest devres of @dev associated with @release and for
 * which @match returns 1.  If @match is NULL, it's considered to
 * match all.  If found, the resource is removed atomically and freed.
 *
 * Note that the release function for the resource will not be called,
 * only the devres-allocated data will be freed.  The caller becomes
 * responsible for freeing any other data.
 *
 * RETURNS:
 * 0 if devres is found and freed, -ENOENT if not found.
 */
int devres_destroy(struct device *dev, dr_release_t release,
		   dr_match_t match, void *match_data)
{
	void *res;

	res = devres_remove(dev, release, match, match_data);
	if (unlikely(!res))
		return -ENOENT;

	devres_free(res);
	return 0;
}
EXPORT_SYMBOL_GPL(devres_destroy);


/**
 * devres_release - Find a device resource and destroy it, calling release
 * @dev: Device to find resource from
 * @release: Look for resources associated with this release function
 * @match: Match function (optional)
 * @match_data: Data for the match function
 *
 * Find the latest devres of @dev associated with @release and for
 * which @match returns 1.  If @match is NULL, it's considered to
 * match all.  If found, the resource is removed atomically, the
 * release function called and the resource freed.
 *
 * RETURNS:
 * 0 if devres is found and freed, -ENOENT if not found.
 */
int devres_release(struct device *dev, dr_release_t release,
		   dr_match_t match, void *match_data)
{
	void *res;

	res = devres_remove(dev, release, match, match_data);
	if (unlikely(!res))
		return -ENOENT;

	(*release)(dev, res);
	devres_free(res);
	return 0;
}
EXPORT_SYMBOL_GPL(devres_release);

static int remove_nodes(struct device *dev,
			struct list_head *first, struct list_head *end,
			struct list_head *todo)
{
	int cnt = 0, nr_groups = 0;
	struct list_head *cur;

	/* First pass - move normal devres entries to @todo and clear
	 * devres_group colors.
	 */
	cur = first;
	while (cur != end) {
		struct devres_node *node;
		struct devres_group *grp;

		node = list_entry(cur, struct devres_node, entry);
		cur = cur->next;

		grp = node_to_group(node);
		if (grp) {
			/* clear color of group markers in the first pass */
			grp->color = 0;
			nr_groups++;
		} else {
			/* regular devres entry */
			if (&node->entry == first)
				first = first->next;
			list_move_tail(&node->entry, todo);
			cnt++;
		}
	}

	if (!nr_groups)
		return cnt;

	/* Second pass - Scan groups and color them.  A group gets
	 * color value of two iff the group is wholly contained in
	 * [cur, end).  That is, for a closed group, both opening and
	 * closing markers should be in the range, while just the
	 * opening marker is enough for an open group.
	 */
	cur = first;
	while (cur != end) {
		struct devres_node *node;
		struct devres_group *grp;

		node = list_entry(cur, struct devres_node, entry);
		cur = cur->next;

		grp = node_to_group(node);
		BUG_ON(!grp || list_empty(&grp->node[0].entry));

		grp->color++;
		if (list_empty(&grp->node[1].entry))
			grp->color++;

		BUG_ON(grp->color <= 0 || grp->color > 2);
		if (grp->color == 2) {
			/* No need to update cur or end.  The removed
			 * nodes are always before both.
			 */
			list_move_tail(&grp->node[0].entry, todo);
			list_del_init(&grp->node[1].entry);
		}
	}

	return cnt;
}

static int release_nodes(struct device *dev, struct list_head *first,
			 struct list_head *end, unsigned long flags)
	__releases(&dev->devres_lock)
{
	LIST_HEAD(todo);
	int cnt;
	struct devres *dr, *tmp;

	cnt = remove_nodes(dev, first, end, &todo);

	spin_unlock_irqrestore(&dev->devres_lock, flags);

	/* Release.  Note that both devres and devres_group are
	 * handled as devres in the following loop.  This is safe.
	 */
	list_for_each_entry_safe_reverse(dr, tmp, &todo, node.entry) {
		devres_log(dev, &dr->node, "REL");
		dr->node.release(dev, dr->data);
		kfree(dr);
	}

	return cnt;
}

/**
 * devres_release_all - Release all managed resources
 * @dev: Device to release resources for
 *
 * Release all resources associated with @dev.  This function is
 * called on driver detach.
 */
int devres_release_all(struct device *dev)
{
	unsigned long flags;

	/* Looks like an uninitialized device structure */
	if (WARN_ON(dev->devres_head.next == NULL))
		return -ENODEV;
	spin_lock_irqsave(&dev->devres_lock, flags);
	return release_nodes(dev, dev->devres_head.next, &dev->devres_head,
			     flags);
}

/**
 * devres_open_group - Open a new devres group
 * @dev: Device to open devres group for
 * @id: Separator ID
 * @gfp: Allocation flags
 *
 * Open a new devres group for @dev with @id.  For @id, using a
 * pointer to an object which won't be used for another group is
 * recommended.  If @id is NULL, address-wise unique ID is created.
 *
 * RETURNS:
 * ID of the new group, NULL on failure.
 */
void * devres_open_group(struct device *dev, void *id, gfp_t gfp)
{
	struct devres_group *grp;
	unsigned long flags;

	grp = kmalloc(sizeof(*grp), gfp);
	if (unlikely(!grp))
		return NULL;

	grp->node[0].release = &group_open_release;
	grp->node[1].release = &group_close_release;
	INIT_LIST_HEAD(&grp->node[0].entry);
	INIT_LIST_HEAD(&grp->node[1].entry);
	set_node_dbginfo(&grp->node[0], "grp<", 0);
	set_node_dbginfo(&grp->node[1], "grp>", 0);
	grp->id = grp;
	if (id)
		grp->id = id;

	spin_lock_irqsave(&dev->devres_lock, flags);
	add_dr(dev, &grp->node[0]);
	spin_unlock_irqrestore(&dev->devres_lock, flags);
	return grp->id;
}
EXPORT_SYMBOL_GPL(devres_open_group);

/* Find devres group with ID @id.  If @id is NULL, look for the latest. */
static struct devres_group * find_group(struct device *dev, void *id)
{
	struct devres_node *node;

	list_for_each_entry_reverse(node, &dev->devres_head, entry) {
		struct devres_group *grp;

		if (node->release != &group_open_release)
			continue;

		grp = container_of(node, struct devres_group, node[0]);

		if (id) {
			if (grp->id == id)
				return grp;
		} else if (list_empty(&grp->node[1].entry))
			return grp;
	}

	return NULL;
}

/**
 * devres_close_group - Close a devres group
 * @dev: Device to close devres group for
 * @id: ID of target group, can be NULL
 *
 * Close the group identified by @id.  If @id is NULL, the latest open
 * group is selected.
 */
void devres_close_group(struct device *dev, void *id)
{
	struct devres_group *grp;
	unsigned long flags;

	spin_lock_irqsave(&dev->devres_lock, flags);

	grp = find_group(dev, id);
	if (grp)
		add_dr(dev, &grp->node[1]);
	else
		WARN_ON(1);

	spin_unlock_irqrestore(&dev->devres_lock, flags);
}
EXPORT_SYMBOL_GPL(devres_close_group);

/**
 * devres_remove_group - Remove a devres group
 * @dev: Device to remove group for
 * @id: ID of target group, can be NULL
 *
 * Remove the group identified by @id.  If @id is NULL, the latest
 * open group is selected.  Note that removing a group doesn't affect
 * any other resources.
 */
void devres_remove_group(struct device *dev, void *id)
{
	struct devres_group *grp;
	unsigned long flags;

	spin_lock_irqsave(&dev->devres_lock, flags);

	grp = find_group(dev, id);
	if (grp) {
		list_del_init(&grp->node[0].entry);
		list_del_init(&grp->node[1].entry);
		devres_log(dev, &grp->node[0], "REM");
	} else
		WARN_ON(1);

	spin_unlock_irqrestore(&dev->devres_lock, flags);

	kfree(grp);
}
EXPORT_SYMBOL_GPL(devres_remove_group);

/**
 * devres_release_group - Release resources in a devres group
 * @dev: Device to release group for
 * @id: ID of target group, can be NULL
 *
 * Release all resources in the group identified by @id.  If @id is
 * NULL, the latest open group is selected.  The selected group and
 * groups properly nested inside the selected group are removed.
 *
 * RETURNS:
 * The number of released non-group resources.
 */
int devres_release_group(struct device *dev, void *id)
{
	struct devres_group *grp;
	unsigned long flags;
	int cnt = 0;

	spin_lock_irqsave(&dev->devres_lock, flags);

	grp = find_group(dev, id);
	if (grp) {
		struct list_head *first = &grp->node[0].entry;
		struct list_head *end = &dev->devres_head;

		if (!list_empty(&grp->node[1].entry))
			end = grp->node[1].entry.next;

		cnt = release_nodes(dev, first, end, flags);
	} else {
		WARN_ON(1);
		spin_unlock_irqrestore(&dev->devres_lock, flags);
	}

	return cnt;
}
EXPORT_SYMBOL_GPL(devres_release_group);

/*
 * Managed kzalloc/kfree
 */
static void devm_kzalloc_release(struct device *dev, void *res)
{
	/* noop */
}

static int devm_kzalloc_match(struct device *dev, void *res, void *data)
{
	return res == data;
}

/**
 * devm_kzalloc - Resource-managed kzalloc
 * @dev: Device to allocate memory for
 * @size: Allocation size
 * @gfp: Allocation gfp flags
 *
 * Managed kzalloc.  Memory allocated with this function is
 * automatically freed on driver detach.  Like all other devres
 * resources, guaranteed alignment is unsigned long long.
 *
 * RETURNS:
 * Pointer to allocated memory on success, NULL on failure.
 */
void * devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
{
	struct devres *dr;

	/* use raw alloc_dr for kmalloc caller tracing */
	dr = alloc_dr(devm_kzalloc_release, size, gfp);
	if (unlikely(!dr))
		return NULL;

	set_node_dbginfo(&dr->node, "devm_kzalloc_release", size);
	devres_add(dev, dr->data);
	return dr->data;
}
EXPORT_SYMBOL_GPL(devm_kzalloc);

/**
 * devm_kfree - Resource-managed kfree
 * @dev: Device this memory belongs to
 * @p: Memory to free
 *
 * Free memory allocated with devm_kzalloc().
 */
void devm_kfree(struct device *dev, void *p)
{
	int rc;

	rc = devres_destroy(dev, devm_kzalloc_release, devm_kzalloc_match, p);
	WARN_ON(rc);
}
EXPORT_SYMBOL_GPL(devm_kfree);