Loading...
Note: File does not exist in v3.1.
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Componentized device handling.
4 *
5 * This is work in progress. We gather up the component devices into a list,
6 * and bind them when instructed. At the moment, we're specific to the DRM
7 * subsystem, and only handles one master device, but this doesn't have to be
8 * the case.
9 */
10#include <linux/component.h>
11#include <linux/device.h>
12#include <linux/kref.h>
13#include <linux/list.h>
14#include <linux/module.h>
15#include <linux/mutex.h>
16#include <linux/slab.h>
17#include <linux/debugfs.h>
18
19struct component;
20
21struct component_match_array {
22 void *data;
23 int (*compare)(struct device *, void *);
24 void (*release)(struct device *, void *);
25 struct component *component;
26 bool duplicate;
27};
28
29struct component_match {
30 size_t alloc;
31 size_t num;
32 struct component_match_array *compare;
33};
34
35struct master {
36 struct list_head node;
37 bool bound;
38
39 const struct component_master_ops *ops;
40 struct device *dev;
41 struct component_match *match;
42 struct dentry *dentry;
43};
44
45struct component {
46 struct list_head node;
47 struct master *master;
48 bool bound;
49
50 const struct component_ops *ops;
51 struct device *dev;
52};
53
54static DEFINE_MUTEX(component_mutex);
55static LIST_HEAD(component_list);
56static LIST_HEAD(masters);
57
58#ifdef CONFIG_DEBUG_FS
59
60static struct dentry *component_debugfs_dir;
61
62static int component_devices_show(struct seq_file *s, void *data)
63{
64 struct master *m = s->private;
65 struct component_match *match = m->match;
66 size_t i;
67
68 mutex_lock(&component_mutex);
69 seq_printf(s, "%-40s %20s\n", "master name", "status");
70 seq_puts(s, "-------------------------------------------------------------\n");
71 seq_printf(s, "%-40s %20s\n\n",
72 dev_name(m->dev), m->bound ? "bound" : "not bound");
73
74 seq_printf(s, "%-40s %20s\n", "device name", "status");
75 seq_puts(s, "-------------------------------------------------------------\n");
76 for (i = 0; i < match->num; i++) {
77 struct device *d = (struct device *)match->compare[i].data;
78
79 seq_printf(s, "%-40s %20s\n", dev_name(d),
80 match->compare[i].component ?
81 "registered" : "not registered");
82 }
83 mutex_unlock(&component_mutex);
84
85 return 0;
86}
87
88static int component_devices_open(struct inode *inode, struct file *file)
89{
90 return single_open(file, component_devices_show, inode->i_private);
91}
92
93static const struct file_operations component_devices_fops = {
94 .open = component_devices_open,
95 .read = seq_read,
96 .llseek = seq_lseek,
97 .release = single_release,
98};
99
100static int __init component_debug_init(void)
101{
102 component_debugfs_dir = debugfs_create_dir("device_component", NULL);
103
104 return 0;
105}
106
107core_initcall(component_debug_init);
108
109static void component_master_debugfs_add(struct master *m)
110{
111 m->dentry = debugfs_create_file(dev_name(m->dev), 0444,
112 component_debugfs_dir,
113 m, &component_devices_fops);
114}
115
116static void component_master_debugfs_del(struct master *m)
117{
118 debugfs_remove(m->dentry);
119 m->dentry = NULL;
120}
121
122#else
123
124static void component_master_debugfs_add(struct master *m)
125{ }
126
127static void component_master_debugfs_del(struct master *m)
128{ }
129
130#endif
131
132static struct master *__master_find(struct device *dev,
133 const struct component_master_ops *ops)
134{
135 struct master *m;
136
137 list_for_each_entry(m, &masters, node)
138 if (m->dev == dev && (!ops || m->ops == ops))
139 return m;
140
141 return NULL;
142}
143
144static struct component *find_component(struct master *master,
145 int (*compare)(struct device *, void *), void *compare_data)
146{
147 struct component *c;
148
149 list_for_each_entry(c, &component_list, node) {
150 if (c->master && c->master != master)
151 continue;
152
153 if (compare(c->dev, compare_data))
154 return c;
155 }
156
157 return NULL;
158}
159
160static int find_components(struct master *master)
161{
162 struct component_match *match = master->match;
163 size_t i;
164 int ret = 0;
165
166 /*
167 * Scan the array of match functions and attach
168 * any components which are found to this master.
169 */
170 for (i = 0; i < match->num; i++) {
171 struct component_match_array *mc = &match->compare[i];
172 struct component *c;
173
174 dev_dbg(master->dev, "Looking for component %zu\n", i);
175
176 if (match->compare[i].component)
177 continue;
178
179 c = find_component(master, mc->compare, mc->data);
180 if (!c) {
181 ret = -ENXIO;
182 break;
183 }
184
185 dev_dbg(master->dev, "found component %s, duplicate %u\n", dev_name(c->dev), !!c->master);
186
187 /* Attach this component to the master */
188 match->compare[i].duplicate = !!c->master;
189 match->compare[i].component = c;
190 c->master = master;
191 }
192 return ret;
193}
194
195/* Detach component from associated master */
196static void remove_component(struct master *master, struct component *c)
197{
198 size_t i;
199
200 /* Detach the component from this master. */
201 for (i = 0; i < master->match->num; i++)
202 if (master->match->compare[i].component == c)
203 master->match->compare[i].component = NULL;
204}
205
206/*
207 * Try to bring up a master. If component is NULL, we're interested in
208 * this master, otherwise it's a component which must be present to try
209 * and bring up the master.
210 *
211 * Returns 1 for successful bringup, 0 if not ready, or -ve errno.
212 */
213static int try_to_bring_up_master(struct master *master,
214 struct component *component)
215{
216 int ret;
217
218 dev_dbg(master->dev, "trying to bring up master\n");
219
220 if (find_components(master)) {
221 dev_dbg(master->dev, "master has incomplete components\n");
222 return 0;
223 }
224
225 if (component && component->master != master) {
226 dev_dbg(master->dev, "master is not for this component (%s)\n",
227 dev_name(component->dev));
228 return 0;
229 }
230
231 if (!devres_open_group(master->dev, NULL, GFP_KERNEL))
232 return -ENOMEM;
233
234 /* Found all components */
235 ret = master->ops->bind(master->dev);
236 if (ret < 0) {
237 devres_release_group(master->dev, NULL);
238 dev_info(master->dev, "master bind failed: %d\n", ret);
239 return ret;
240 }
241
242 master->bound = true;
243 return 1;
244}
245
246static int try_to_bring_up_masters(struct component *component)
247{
248 struct master *m;
249 int ret = 0;
250
251 list_for_each_entry(m, &masters, node) {
252 if (!m->bound) {
253 ret = try_to_bring_up_master(m, component);
254 if (ret != 0)
255 break;
256 }
257 }
258
259 return ret;
260}
261
262static void take_down_master(struct master *master)
263{
264 if (master->bound) {
265 master->ops->unbind(master->dev);
266 devres_release_group(master->dev, NULL);
267 master->bound = false;
268 }
269}
270
271static void component_match_release(struct device *master,
272 struct component_match *match)
273{
274 unsigned int i;
275
276 for (i = 0; i < match->num; i++) {
277 struct component_match_array *mc = &match->compare[i];
278
279 if (mc->release)
280 mc->release(master, mc->data);
281 }
282
283 kfree(match->compare);
284}
285
286static void devm_component_match_release(struct device *dev, void *res)
287{
288 component_match_release(dev, res);
289}
290
291static int component_match_realloc(struct device *dev,
292 struct component_match *match, size_t num)
293{
294 struct component_match_array *new;
295
296 if (match->alloc == num)
297 return 0;
298
299 new = kmalloc_array(num, sizeof(*new), GFP_KERNEL);
300 if (!new)
301 return -ENOMEM;
302
303 if (match->compare) {
304 memcpy(new, match->compare, sizeof(*new) *
305 min(match->num, num));
306 kfree(match->compare);
307 }
308 match->compare = new;
309 match->alloc = num;
310
311 return 0;
312}
313
314/*
315 * Add a component to be matched, with a release function.
316 *
317 * The match array is first created or extended if necessary.
318 */
319void component_match_add_release(struct device *master,
320 struct component_match **matchptr,
321 void (*release)(struct device *, void *),
322 int (*compare)(struct device *, void *), void *compare_data)
323{
324 struct component_match *match = *matchptr;
325
326 if (IS_ERR(match))
327 return;
328
329 if (!match) {
330 match = devres_alloc(devm_component_match_release,
331 sizeof(*match), GFP_KERNEL);
332 if (!match) {
333 *matchptr = ERR_PTR(-ENOMEM);
334 return;
335 }
336
337 devres_add(master, match);
338
339 *matchptr = match;
340 }
341
342 if (match->num == match->alloc) {
343 size_t new_size = match->alloc + 16;
344 int ret;
345
346 ret = component_match_realloc(master, match, new_size);
347 if (ret) {
348 *matchptr = ERR_PTR(ret);
349 return;
350 }
351 }
352
353 match->compare[match->num].compare = compare;
354 match->compare[match->num].release = release;
355 match->compare[match->num].data = compare_data;
356 match->compare[match->num].component = NULL;
357 match->num++;
358}
359EXPORT_SYMBOL(component_match_add_release);
360
361static void free_master(struct master *master)
362{
363 struct component_match *match = master->match;
364 int i;
365
366 component_master_debugfs_del(master);
367 list_del(&master->node);
368
369 if (match) {
370 for (i = 0; i < match->num; i++) {
371 struct component *c = match->compare[i].component;
372 if (c)
373 c->master = NULL;
374 }
375 }
376
377 kfree(master);
378}
379
380int component_master_add_with_match(struct device *dev,
381 const struct component_master_ops *ops,
382 struct component_match *match)
383{
384 struct master *master;
385 int ret;
386
387 /* Reallocate the match array for its true size */
388 ret = component_match_realloc(dev, match, match->num);
389 if (ret)
390 return ret;
391
392 master = kzalloc(sizeof(*master), GFP_KERNEL);
393 if (!master)
394 return -ENOMEM;
395
396 master->dev = dev;
397 master->ops = ops;
398 master->match = match;
399
400 component_master_debugfs_add(master);
401 /* Add to the list of available masters. */
402 mutex_lock(&component_mutex);
403 list_add(&master->node, &masters);
404
405 ret = try_to_bring_up_master(master, NULL);
406
407 if (ret < 0)
408 free_master(master);
409
410 mutex_unlock(&component_mutex);
411
412 return ret < 0 ? ret : 0;
413}
414EXPORT_SYMBOL_GPL(component_master_add_with_match);
415
416void component_master_del(struct device *dev,
417 const struct component_master_ops *ops)
418{
419 struct master *master;
420
421 mutex_lock(&component_mutex);
422 master = __master_find(dev, ops);
423 if (master) {
424 take_down_master(master);
425 free_master(master);
426 }
427 mutex_unlock(&component_mutex);
428}
429EXPORT_SYMBOL_GPL(component_master_del);
430
431static void component_unbind(struct component *component,
432 struct master *master, void *data)
433{
434 WARN_ON(!component->bound);
435
436 component->ops->unbind(component->dev, master->dev, data);
437 component->bound = false;
438
439 /* Release all resources claimed in the binding of this component */
440 devres_release_group(component->dev, component);
441}
442
443void component_unbind_all(struct device *master_dev, void *data)
444{
445 struct master *master;
446 struct component *c;
447 size_t i;
448
449 WARN_ON(!mutex_is_locked(&component_mutex));
450
451 master = __master_find(master_dev, NULL);
452 if (!master)
453 return;
454
455 /* Unbind components in reverse order */
456 for (i = master->match->num; i--; )
457 if (!master->match->compare[i].duplicate) {
458 c = master->match->compare[i].component;
459 component_unbind(c, master, data);
460 }
461}
462EXPORT_SYMBOL_GPL(component_unbind_all);
463
464static int component_bind(struct component *component, struct master *master,
465 void *data)
466{
467 int ret;
468
469 /*
470 * Each component initialises inside its own devres group.
471 * This allows us to roll-back a failed component without
472 * affecting anything else.
473 */
474 if (!devres_open_group(master->dev, NULL, GFP_KERNEL))
475 return -ENOMEM;
476
477 /*
478 * Also open a group for the device itself: this allows us
479 * to release the resources claimed against the sub-device
480 * at the appropriate moment.
481 */
482 if (!devres_open_group(component->dev, component, GFP_KERNEL)) {
483 devres_release_group(master->dev, NULL);
484 return -ENOMEM;
485 }
486
487 dev_dbg(master->dev, "binding %s (ops %ps)\n",
488 dev_name(component->dev), component->ops);
489
490 ret = component->ops->bind(component->dev, master->dev, data);
491 if (!ret) {
492 component->bound = true;
493
494 /*
495 * Close the component device's group so that resources
496 * allocated in the binding are encapsulated for removal
497 * at unbind. Remove the group on the DRM device as we
498 * can clean those resources up independently.
499 */
500 devres_close_group(component->dev, NULL);
501 devres_remove_group(master->dev, NULL);
502
503 dev_info(master->dev, "bound %s (ops %ps)\n",
504 dev_name(component->dev), component->ops);
505 } else {
506 devres_release_group(component->dev, NULL);
507 devres_release_group(master->dev, NULL);
508
509 dev_err(master->dev, "failed to bind %s (ops %ps): %d\n",
510 dev_name(component->dev), component->ops, ret);
511 }
512
513 return ret;
514}
515
516int component_bind_all(struct device *master_dev, void *data)
517{
518 struct master *master;
519 struct component *c;
520 size_t i;
521 int ret = 0;
522
523 WARN_ON(!mutex_is_locked(&component_mutex));
524
525 master = __master_find(master_dev, NULL);
526 if (!master)
527 return -EINVAL;
528
529 /* Bind components in match order */
530 for (i = 0; i < master->match->num; i++)
531 if (!master->match->compare[i].duplicate) {
532 c = master->match->compare[i].component;
533 ret = component_bind(c, master, data);
534 if (ret)
535 break;
536 }
537
538 if (ret != 0) {
539 for (; i--; )
540 if (!master->match->compare[i].duplicate) {
541 c = master->match->compare[i].component;
542 component_unbind(c, master, data);
543 }
544 }
545
546 return ret;
547}
548EXPORT_SYMBOL_GPL(component_bind_all);
549
550int component_add(struct device *dev, const struct component_ops *ops)
551{
552 struct component *component;
553 int ret;
554
555 component = kzalloc(sizeof(*component), GFP_KERNEL);
556 if (!component)
557 return -ENOMEM;
558
559 component->ops = ops;
560 component->dev = dev;
561
562 dev_dbg(dev, "adding component (ops %ps)\n", ops);
563
564 mutex_lock(&component_mutex);
565 list_add_tail(&component->node, &component_list);
566
567 ret = try_to_bring_up_masters(component);
568 if (ret < 0) {
569 if (component->master)
570 remove_component(component->master, component);
571 list_del(&component->node);
572
573 kfree(component);
574 }
575 mutex_unlock(&component_mutex);
576
577 return ret < 0 ? ret : 0;
578}
579EXPORT_SYMBOL_GPL(component_add);
580
581void component_del(struct device *dev, const struct component_ops *ops)
582{
583 struct component *c, *component = NULL;
584
585 mutex_lock(&component_mutex);
586 list_for_each_entry(c, &component_list, node)
587 if (c->dev == dev && c->ops == ops) {
588 list_del(&c->node);
589 component = c;
590 break;
591 }
592
593 if (component && component->master) {
594 take_down_master(component->master);
595 remove_component(component->master, component);
596 }
597
598 mutex_unlock(&component_mutex);
599
600 WARN_ON(!component);
601 kfree(component);
602}
603EXPORT_SYMBOL_GPL(component_del);
604
605MODULE_LICENSE("GPL v2");