summaryrefslogtreecommitdiffstats
path: root/drivers/base/component.c
blob: 8946dfee4768e8a82fb35f994b4e9ff2b88c245a (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
// SPDX-License-Identifier: GPL-2.0
/*
 * Componentized device handling.
 *
 * This is work in progress.  We gather up the component devices into a list,
 * and bind them when instructed.  At the moment, we're specific to the DRM
 * subsystem, and only handles one master device, but this doesn't have to be
 * the case.
 */
#include <linux/component.h>
#include <linux/device.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/debugfs.h>

struct component;

struct component_match_array {
	void *data;
	int (*compare)(struct device *, void *);
	void (*release)(struct device *, void *);
	struct component *component;
	bool duplicate;
};

struct component_match {
	size_t alloc;
	size_t num;
	struct component_match_array *compare;
};

struct master {
	struct list_head node;
	bool bound;

	const struct component_master_ops *ops;
	struct device *dev;
	struct component_match *match;
	struct dentry *dentry;
};

struct component {
	struct list_head node;
	struct master *master;
	bool bound;

	const struct component_ops *ops;
	struct device *dev;
};

static DEFINE_MUTEX(component_mutex);
static LIST_HEAD(component_list);
static LIST_HEAD(masters);

#ifdef CONFIG_DEBUG_FS

static struct dentry *component_debugfs_dir;

static int component_devices_show(struct seq_file *s, void *data)
{
	struct master *m = s->private;
	struct component_match *match = m->match;
	size_t i;

	mutex_lock(&component_mutex);
	seq_printf(s, "%-40s %20s\n", "master name", "status");
	seq_puts(s, "-------------------------------------------------------------\n");
	seq_printf(s, "%-40s %20s\n\n",
		   dev_name(m->dev), m->bound ? "bound" : "not bound");

	seq_printf(s, "%-40s %20s\n", "device name", "status");
	seq_puts(s, "-------------------------------------------------------------\n");
	for (i = 0; i < match->num; i++) {
		struct device *d = (struct device *)match->compare[i].data;

		seq_printf(s, "%-40s %20s\n", dev_name(d),
			   match->compare[i].component ?
			   "registered" : "not registered");
	}
	mutex_unlock(&component_mutex);

	return 0;
}

static int component_devices_open(struct inode *inode, struct file *file)
{
	return single_open(file, component_devices_show, inode->i_private);
}

static const struct file_operations component_devices_fops = {
	.open = component_devices_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};

static int __init component_debug_init(void)
{
	component_debugfs_dir = debugfs_create_dir("device_component", NULL);

	return 0;
}

core_initcall(component_debug_init);

static void component_master_debugfs_add(struct master *m)
{
	m->dentry = debugfs_create_file(dev_name(m->dev), 0444,
					component_debugfs_dir,
					m, &component_devices_fops);
}

static void component_master_debugfs_del(struct master *m)
{
	debugfs_remove(m->dentry);
	m->dentry = NULL;
}

#else

static void component_master_debugfs_add(struct master *m)
{ }

static void component_master_debugfs_del(struct master *m)
{ }

#endif

static struct master *__master_find(struct device *dev,
	const struct component_master_ops *ops)
{
	struct master *m;

	list_for_each_entry(m, &masters, node)
		if (m->dev == dev && (!ops || m->ops == ops))
			return m;

	return NULL;
}

static struct component *find_component(struct master *master,
	int (*compare)(struct device *, void *), void *compare_data)
{
	struct component *c;

	list_for_each_entry(c, &component_list, node) {
		if (c->master && c->master != master)
			continue;

		if (compare(c->dev, compare_data))
			return c;
	}

	return NULL;
}

static int find_components(struct master *master)
{
	struct component_match *match = master->match;
	size_t i;
	int ret = 0;

	/*
	 * Scan the array of match functions and attach
	 * any components which are found to this master.
	 */
	for (i = 0; i < match->num; i++) {
		struct component_match_array *mc = &match->compare[i];
		struct component *c;

		dev_dbg(master->dev, "Looking for component %zu\n", i);

		if (match->compare[i].component)
			continue;

		c = find_component(master, mc->compare, mc->data);
		if (!c) {
			ret = -ENXIO;
			break;
		}

		dev_dbg(master->dev, "found component %s, duplicate %u\n", dev_name(c->dev), !!c->master);

		/* Attach this component to the master */
		match->compare[i].duplicate = !!c->master;
		match->compare[i].component = c;
		c->master = master;
	}
	return ret;
}

/* Detach component from associated master */
static void remove_component(struct master *master, struct component *c)
{
	size_t i;

	/* Detach the component from this master. */
	for (i = 0; i < master->match->num; i++)
		if (master->match->compare[i].component == c)
			master->match->compare[i].component = NULL;
}

/*
 * Try to bring up a master.  If component is NULL, we're interested in
 * this master, otherwise it's a component which must be present to try
 * and bring up the master.
 *
 * Returns 1 for successful bringup, 0 if not ready, or -ve errno.
 */
static int try_to_bring_up_master(struct master *master,
	struct component *component)
{
	int ret;

	dev_dbg(master->dev, "trying to bring up master\n");

	if (find_components(master)) {
		dev_dbg(master->dev, "master has incomplete components\n");
		return 0;
	}

	if (component && component->master != master) {
		dev_dbg(master->dev, "master is not for this component (%s)\n",
			dev_name(component->dev));
		return 0;
	}

	if (!devres_open_group(master->dev, NULL, GFP_KERNEL))
		return -ENOMEM;

	/* Found all components */
	ret = master->ops->bind(master->dev);
	if (ret < 0) {
		devres_release_group(master->dev, NULL);
		dev_info(master->dev, "master bind failed: %d\n", ret);
		return ret;
	}

	master->bound = true;
	return 1;
}

static int try_to_bring_up_masters(struct component *component)
{
	struct master *m;
	int ret = 0;

	list_for_each_entry(m, &masters, node) {
		if (!m->bound) {
			ret = try_to_bring_up_master(m, component);
			if (ret != 0)
				break;
		}
	}

	return ret;
}

static void take_down_master(struct master *master)
{
	if (master->bound) {
		master->ops->unbind(master->dev);
		devres_release_group(master->dev, NULL);
		master->bound = false;
	}
}

static void component_match_release(struct device *master,
	struct component_match *match)
{
	unsigned int i;

	for (i = 0; i < match->num; i++) {
		struct component_match_array *mc = &match->compare[i];

		if (mc->release)
			mc->release(master, mc->data);
	}

	kfree(match->compare);
}

static void devm_component_match_release(struct device *dev, void *res)
{
	component_match_release(dev, res);
}

static int component_match_realloc(struct device *dev,
	struct component_match *match, size_t num)
{
	struct component_match_array *new;

	if (match->alloc == num)
		return 0;

	new = kmalloc_array(num, sizeof(*new), GFP_KERNEL);
	if (!new)
		return -ENOMEM;

	if (match->compare) {
		memcpy(new, match->compare, sizeof(*new) *
					    min(match->num, num));
		kfree(match->compare);
	}
	match->compare = new;
	match->alloc = num;

	return 0;
}

/*
 * Add a component to be matched, with a release function.
 *
 * The match array is first created or extended if necessary.
 */
void component_match_add_release(struct device *master,
	struct component_match **matchptr,
	void (*release)(struct device *, void *),
	int (*compare)(struct device *, void *), void *compare_data)
{
	struct component_match *match = *matchptr;

	if (IS_ERR(match))
		return;

	if (!match) {
		match = devres_alloc(devm_component_match_release,
				     sizeof(*match), GFP_KERNEL);
		if (!match) {
			*matchptr = ERR_PTR(-ENOMEM);
			return;
		}

		devres_add(master, match);

		*matchptr = match;
	}

	if (match->num == match->alloc) {
		size_t new_size = match->alloc + 16;
		int ret;

		ret = component_match_realloc(master, match, new_size);
		if (ret) {
			*matchptr = ERR_PTR(ret);
			return;
		}
	}

	match->compare[match->num].compare = compare;
	match->compare[match->num].release = release;
	match->compare[match->num].data = compare_data;
	match->compare[match->num].component = NULL;
	match->num++;
}
EXPORT_SYMBOL(component_match_add_release);

static void free_master(struct master *master)
{
	struct component_match *match = master->match;
	int i;

	component_master_debugfs_del(master);
	list_del(&master->node);

	if (match) {
		for (i = 0; i < match->num; i++) {
			struct component *c = match->compare[i].component;
			if (c)
				c->master = NULL;
		}
	}

	kfree(master);
}

int component_master_add_with_match(struct device *dev,
	const struct component_master_ops *ops,
	struct component_match *match)
{
	struct master *master;
	int ret;

	/* Reallocate the match array for its true size */
	ret = component_match_realloc(dev, match, match->num);
	if (ret)
		return ret;

	master = kzalloc(sizeof(*master), GFP_KERNEL);
	if (!master)
		return -ENOMEM;

	master->dev = dev;
	master->ops = ops;
	master->match = match;

	component_master_debugfs_add(master);
	/* Add to the list of available masters. */
	mutex_lock(&component_mutex);
	list_add(&master->node, &masters);

	ret = try_to_bring_up_master(master, NULL);

	if (ret < 0)
		free_master(master);

	mutex_unlock(&component_mutex);

	return ret < 0 ? ret : 0;
}
EXPORT_SYMBOL_GPL(component_master_add_with_match);

void component_master_del(struct device *dev,
	const struct component_master_ops *ops)
{
	struct master *master;

	mutex_lock(&component_mutex);
	master = __master_find(dev, ops);
	if (master) {
		take_down_master(master);
		free_master(master);
	}
	mutex_unlock(&component_mutex);
}
EXPORT_SYMBOL_GPL(component_master_del);

static void component_unbind(struct component *component,
	struct master *master, void *data)
{
	WARN_ON(!component->bound);

	component->ops->unbind(component->dev, master->dev, data);
	component->bound = false;

	/* Release all resources claimed in the binding of this component */
	devres_release_group(component->dev, component);
}

void component_unbind_all(struct device *master_dev, void *data)
{
	struct master *master;
	struct component *c;
	size_t i;

	WARN_ON(!mutex_is_locked(&component_mutex));

	master = __master_find(master_dev, NULL);
	if (!master)
		return;

	/* Unbind components in reverse order */
	for (i = master->match->num; i--; )
		if (!master->match->compare[i].duplicate) {
			c = master->match->compare[i].component;
			component_unbind(c, master, data);
		}
}
EXPORT_SYMBOL_GPL(component_unbind_all);

static int component_bind(struct component *component, struct master *master,
	void *data)
{
	int ret;

	/*
	 * Each component initialises inside its own devres group.
	 * This allows us to roll-back a failed component without
	 * affecting anything else.
	 */
	if (!devres_open_group(master->dev, NULL, GFP_KERNEL))
		return -ENOMEM;

	/*
	 * Also open a group for the device itself: this allows us
	 * to release the resources claimed against the sub-device
	 * at the appropriate moment.
	 */
	if (!devres_open_group(component->dev, component, GFP_KERNEL)) {
		devres_release_group(master->dev, NULL);
		return -ENOMEM;
	}

	dev_dbg(master->dev, "binding %s (ops %ps)\n",
		dev_name(component->dev), component->ops);

	ret = component->ops->bind(component->dev, master->dev, data);
	if (!ret) {
		component->bound = true;

		/*
		 * Close the component device's group so that resources
		 * allocated in the binding are encapsulated for removal
		 * at unbind.  Remove the group on the DRM device as we
		 * can clean those resources up independently.
		 */
		devres_close_group(component->dev, NULL);
		devres_remove_group(master->dev, NULL);

		dev_info(master->dev, "bound %s (ops %ps)\n",
			 dev_name(component->dev), component->ops);
	} else {
		devres_release_group(component->dev, NULL);
		devres_release_group(master->dev, NULL);

		dev_err(master->dev, "failed to bind %s (ops %ps): %d\n",
			dev_name(component->dev), component->ops, ret);
	}

	return ret;
}

int component_bind_all(struct device *master_dev, void *data)
{
	struct master *master;
	struct component *c;
	size_t i;
	int ret = 0;

	WARN_ON(!mutex_is_locked(&component_mutex));

	master = __master_find(master_dev, NULL);
	if (!master)
		return -EINVAL;

	/* Bind components in match order */
	for (i = 0; i < master->match->num; i++)
		if (!master->match->compare[i].duplicate) {
			c = master->match->compare[i].component;
			ret = component_bind(c, master, data);
			if (ret)
				break;
		}

	if (ret != 0) {
		for (; i--; )
			if (!master->match->compare[i].duplicate) {
				c = master->match->compare[i].component;
				component_unbind(c, master, data);
			}
	}

	return ret;
}
EXPORT_SYMBOL_GPL(component_bind_all);

int component_add(struct device *dev, const struct component_ops *ops)
{
	struct component *component;
	int ret;

	component = kzalloc(sizeof(*component), GFP_KERNEL);
	if (!component)
		return -ENOMEM;

	component->ops = ops;
	component->dev = dev;

	dev_dbg(dev, "adding component (ops %ps)\n", ops);

	mutex_lock(&component_mutex);
	list_add_tail(&component->node, &component_list);

	ret = try_to_bring_up_masters(component);
	if (ret < 0) {
		if (component->master)
			remove_component(component->master, component);
		list_del(&component->node);

		kfree(component);
	}
	mutex_unlock(&component_mutex);

	return ret < 0 ? ret : 0;
}
EXPORT_SYMBOL_GPL(component_add);

void component_del(struct device *dev, const struct component_ops *ops)
{
	struct component *c, *component = NULL;

	mutex_lock(&component_mutex);
	list_for_each_entry(c, &component_list, node)
		if (c->dev == dev && c->ops == ops) {
			list_del(&c->node);
			component = c;
			break;
		}

	if (component && component->master) {
		take_down_master(component->master);
		remove_component(component->master, component);
	}

	mutex_unlock(&component_mutex);

	WARN_ON(!component);
	kfree(component);
}
EXPORT_SYMBOL_GPL(component_del);

MODULE_LICENSE("GPL v2");