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2a41e607 RK |
1 | /* |
2 | * Componentized device handling. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * This is work in progress. We gather up the component devices into a list, | |
9 | * and bind them when instructed. At the moment, we're specific to the DRM | |
10 | * subsystem, and only handles one master device, but this doesn't have to be | |
11 | * the case. | |
12 | */ | |
13 | #include <linux/component.h> | |
14 | #include <linux/device.h> | |
15 | #include <linux/kref.h> | |
16 | #include <linux/list.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/mutex.h> | |
19 | #include <linux/slab.h> | |
20 | ||
6955b582 RK |
21 | struct component_match { |
22 | size_t alloc; | |
23 | size_t num; | |
24 | struct { | |
25 | void *data; | |
26 | int (*fn)(struct device *, void *); | |
27 | } compare[0]; | |
28 | }; | |
29 | ||
2a41e607 RK |
30 | struct master { |
31 | struct list_head node; | |
32 | struct list_head components; | |
33 | bool bound; | |
34 | ||
35 | const struct component_master_ops *ops; | |
36 | struct device *dev; | |
6955b582 | 37 | struct component_match *match; |
2a41e607 RK |
38 | }; |
39 | ||
40 | struct component { | |
41 | struct list_head node; | |
42 | struct list_head master_node; | |
43 | struct master *master; | |
44 | bool bound; | |
45 | ||
46 | const struct component_ops *ops; | |
47 | struct device *dev; | |
48 | }; | |
49 | ||
50 | static DEFINE_MUTEX(component_mutex); | |
51 | static LIST_HEAD(component_list); | |
52 | static LIST_HEAD(masters); | |
53 | ||
54 | static struct master *__master_find(struct device *dev, | |
55 | const struct component_master_ops *ops) | |
56 | { | |
57 | struct master *m; | |
58 | ||
59 | list_for_each_entry(m, &masters, node) | |
60 | if (m->dev == dev && (!ops || m->ops == ops)) | |
61 | return m; | |
62 | ||
63 | return NULL; | |
64 | } | |
65 | ||
66 | /* Attach an unattached component to a master. */ | |
67 | static void component_attach_master(struct master *master, struct component *c) | |
68 | { | |
69 | c->master = master; | |
70 | ||
71 | list_add_tail(&c->master_node, &master->components); | |
72 | } | |
73 | ||
74 | /* Detach a component from a master. */ | |
75 | static void component_detach_master(struct master *master, struct component *c) | |
76 | { | |
77 | list_del(&c->master_node); | |
78 | ||
79 | c->master = NULL; | |
80 | } | |
81 | ||
fcbcebce RK |
82 | /* |
83 | * Add a component to a master, finding the component via the compare | |
84 | * function and compare data. This is safe to call for duplicate matches | |
85 | * and will not result in the same component being added multiple times. | |
86 | */ | |
2a41e607 RK |
87 | int component_master_add_child(struct master *master, |
88 | int (*compare)(struct device *, void *), void *compare_data) | |
89 | { | |
90 | struct component *c; | |
91 | int ret = -ENXIO; | |
92 | ||
93 | list_for_each_entry(c, &component_list, node) { | |
fcbcebce | 94 | if (c->master && c->master != master) |
2a41e607 RK |
95 | continue; |
96 | ||
97 | if (compare(c->dev, compare_data)) { | |
fcbcebce RK |
98 | if (!c->master) |
99 | component_attach_master(master, c); | |
2a41e607 RK |
100 | ret = 0; |
101 | break; | |
102 | } | |
103 | } | |
104 | ||
105 | return ret; | |
106 | } | |
107 | EXPORT_SYMBOL_GPL(component_master_add_child); | |
108 | ||
6955b582 RK |
109 | static int find_components(struct master *master) |
110 | { | |
111 | struct component_match *match = master->match; | |
112 | size_t i; | |
113 | int ret = 0; | |
114 | ||
115 | if (!match) { | |
116 | /* | |
117 | * Search the list of components, looking for components that | |
118 | * belong to this master, and attach them to the master. | |
119 | */ | |
120 | return master->ops->add_components(master->dev, master); | |
121 | } | |
122 | ||
123 | /* | |
124 | * Scan the array of match functions and attach | |
125 | * any components which are found to this master. | |
126 | */ | |
127 | for (i = 0; i < match->num; i++) { | |
128 | ret = component_master_add_child(master, | |
129 | match->compare[i].fn, | |
130 | match->compare[i].data); | |
131 | if (ret) | |
132 | break; | |
133 | } | |
134 | return ret; | |
135 | } | |
136 | ||
2a41e607 RK |
137 | /* Detach all attached components from this master */ |
138 | static void master_remove_components(struct master *master) | |
139 | { | |
140 | while (!list_empty(&master->components)) { | |
141 | struct component *c = list_first_entry(&master->components, | |
142 | struct component, master_node); | |
143 | ||
144 | WARN_ON(c->master != master); | |
145 | ||
146 | component_detach_master(master, c); | |
147 | } | |
148 | } | |
149 | ||
150 | /* | |
151 | * Try to bring up a master. If component is NULL, we're interested in | |
152 | * this master, otherwise it's a component which must be present to try | |
153 | * and bring up the master. | |
154 | * | |
155 | * Returns 1 for successful bringup, 0 if not ready, or -ve errno. | |
156 | */ | |
157 | static int try_to_bring_up_master(struct master *master, | |
158 | struct component *component) | |
159 | { | |
c334940e RK |
160 | int ret; |
161 | ||
162 | if (master->bound) | |
163 | return 0; | |
164 | ||
165 | /* | |
166 | * Search the list of components, looking for components that | |
167 | * belong to this master, and attach them to the master. | |
168 | */ | |
6955b582 | 169 | if (find_components(master)) { |
c334940e RK |
170 | /* Failed to find all components */ |
171 | ret = 0; | |
172 | goto out; | |
173 | } | |
2a41e607 | 174 | |
c334940e RK |
175 | if (component && component->master != master) { |
176 | ret = 0; | |
177 | goto out; | |
178 | } | |
2a41e607 | 179 | |
c334940e RK |
180 | if (!devres_open_group(master->dev, NULL, GFP_KERNEL)) { |
181 | ret = -ENOMEM; | |
182 | goto out; | |
183 | } | |
2a41e607 | 184 | |
c334940e RK |
185 | /* Found all components */ |
186 | ret = master->ops->bind(master->dev); | |
187 | if (ret < 0) { | |
188 | devres_release_group(master->dev, NULL); | |
189 | dev_info(master->dev, "master bind failed: %d\n", ret); | |
190 | goto out; | |
191 | } | |
9e1ccb4a | 192 | |
c334940e RK |
193 | master->bound = true; |
194 | return 1; | |
2a41e607 | 195 | |
2a41e607 | 196 | out: |
c334940e | 197 | master_remove_components(master); |
2a41e607 RK |
198 | |
199 | return ret; | |
200 | } | |
201 | ||
202 | static int try_to_bring_up_masters(struct component *component) | |
203 | { | |
204 | struct master *m; | |
205 | int ret = 0; | |
206 | ||
207 | list_for_each_entry(m, &masters, node) { | |
208 | ret = try_to_bring_up_master(m, component); | |
209 | if (ret != 0) | |
210 | break; | |
211 | } | |
212 | ||
213 | return ret; | |
214 | } | |
215 | ||
216 | static void take_down_master(struct master *master) | |
217 | { | |
218 | if (master->bound) { | |
219 | master->ops->unbind(master->dev); | |
9e1ccb4a | 220 | devres_release_group(master->dev, NULL); |
2a41e607 RK |
221 | master->bound = false; |
222 | } | |
223 | ||
224 | master_remove_components(master); | |
225 | } | |
226 | ||
6955b582 RK |
227 | static size_t component_match_size(size_t num) |
228 | { | |
229 | return offsetof(struct component_match, compare[num]); | |
230 | } | |
231 | ||
232 | static struct component_match *component_match_realloc(struct device *dev, | |
233 | struct component_match *match, size_t num) | |
234 | { | |
235 | struct component_match *new; | |
236 | ||
237 | if (match && match->alloc == num) | |
238 | return match; | |
239 | ||
240 | new = devm_kmalloc(dev, component_match_size(num), GFP_KERNEL); | |
241 | if (!new) | |
242 | return ERR_PTR(-ENOMEM); | |
243 | ||
244 | if (match) { | |
245 | memcpy(new, match, component_match_size(min(match->num, num))); | |
246 | devm_kfree(dev, match); | |
247 | } else { | |
248 | new->num = 0; | |
249 | } | |
250 | ||
251 | new->alloc = num; | |
252 | ||
253 | return new; | |
254 | } | |
255 | ||
256 | /* | |
257 | * Add a component to be matched. | |
258 | * | |
259 | * The match array is first created or extended if necessary. | |
260 | */ | |
261 | void component_match_add(struct device *dev, struct component_match **matchptr, | |
262 | int (*compare)(struct device *, void *), void *compare_data) | |
263 | { | |
264 | struct component_match *match = *matchptr; | |
265 | ||
266 | if (IS_ERR(match)) | |
267 | return; | |
268 | ||
269 | if (!match || match->num == match->alloc) { | |
270 | size_t new_size = match ? match->alloc + 16 : 15; | |
271 | ||
272 | match = component_match_realloc(dev, match, new_size); | |
273 | ||
274 | *matchptr = match; | |
275 | ||
276 | if (IS_ERR(match)) | |
277 | return; | |
278 | } | |
279 | ||
280 | match->compare[match->num].fn = compare; | |
281 | match->compare[match->num].data = compare_data; | |
282 | match->num++; | |
283 | } | |
284 | EXPORT_SYMBOL(component_match_add); | |
285 | ||
286 | int component_master_add_with_match(struct device *dev, | |
287 | const struct component_master_ops *ops, | |
288 | struct component_match *match) | |
2a41e607 RK |
289 | { |
290 | struct master *master; | |
291 | int ret; | |
292 | ||
6955b582 RK |
293 | if (ops->add_components && match) |
294 | return -EINVAL; | |
295 | ||
b509cc80 RK |
296 | if (match) { |
297 | /* Reallocate the match array for its true size */ | |
298 | match = component_match_realloc(dev, match, match->num); | |
299 | if (IS_ERR(match)) | |
300 | return PTR_ERR(match); | |
301 | } | |
6955b582 | 302 | |
2a41e607 RK |
303 | master = kzalloc(sizeof(*master), GFP_KERNEL); |
304 | if (!master) | |
305 | return -ENOMEM; | |
306 | ||
307 | master->dev = dev; | |
308 | master->ops = ops; | |
6955b582 | 309 | master->match = match; |
2a41e607 RK |
310 | INIT_LIST_HEAD(&master->components); |
311 | ||
312 | /* Add to the list of available masters. */ | |
313 | mutex_lock(&component_mutex); | |
314 | list_add(&master->node, &masters); | |
315 | ||
316 | ret = try_to_bring_up_master(master, NULL); | |
317 | ||
318 | if (ret < 0) { | |
319 | /* Delete off the list if we weren't successful */ | |
320 | list_del(&master->node); | |
321 | kfree(master); | |
322 | } | |
323 | mutex_unlock(&component_mutex); | |
324 | ||
325 | return ret < 0 ? ret : 0; | |
326 | } | |
6955b582 RK |
327 | EXPORT_SYMBOL_GPL(component_master_add_with_match); |
328 | ||
329 | int component_master_add(struct device *dev, | |
330 | const struct component_master_ops *ops) | |
331 | { | |
332 | return component_master_add_with_match(dev, ops, NULL); | |
333 | } | |
2a41e607 RK |
334 | EXPORT_SYMBOL_GPL(component_master_add); |
335 | ||
336 | void component_master_del(struct device *dev, | |
337 | const struct component_master_ops *ops) | |
338 | { | |
339 | struct master *master; | |
340 | ||
341 | mutex_lock(&component_mutex); | |
342 | master = __master_find(dev, ops); | |
343 | if (master) { | |
344 | take_down_master(master); | |
345 | ||
346 | list_del(&master->node); | |
347 | kfree(master); | |
348 | } | |
349 | mutex_unlock(&component_mutex); | |
350 | } | |
351 | EXPORT_SYMBOL_GPL(component_master_del); | |
352 | ||
353 | static void component_unbind(struct component *component, | |
354 | struct master *master, void *data) | |
355 | { | |
356 | WARN_ON(!component->bound); | |
357 | ||
358 | component->ops->unbind(component->dev, master->dev, data); | |
359 | component->bound = false; | |
360 | ||
361 | /* Release all resources claimed in the binding of this component */ | |
362 | devres_release_group(component->dev, component); | |
363 | } | |
364 | ||
365 | void component_unbind_all(struct device *master_dev, void *data) | |
366 | { | |
367 | struct master *master; | |
368 | struct component *c; | |
369 | ||
370 | WARN_ON(!mutex_is_locked(&component_mutex)); | |
371 | ||
372 | master = __master_find(master_dev, NULL); | |
373 | if (!master) | |
374 | return; | |
375 | ||
376 | list_for_each_entry_reverse(c, &master->components, master_node) | |
377 | component_unbind(c, master, data); | |
378 | } | |
379 | EXPORT_SYMBOL_GPL(component_unbind_all); | |
380 | ||
381 | static int component_bind(struct component *component, struct master *master, | |
382 | void *data) | |
383 | { | |
384 | int ret; | |
385 | ||
386 | /* | |
387 | * Each component initialises inside its own devres group. | |
388 | * This allows us to roll-back a failed component without | |
389 | * affecting anything else. | |
390 | */ | |
391 | if (!devres_open_group(master->dev, NULL, GFP_KERNEL)) | |
392 | return -ENOMEM; | |
393 | ||
394 | /* | |
395 | * Also open a group for the device itself: this allows us | |
396 | * to release the resources claimed against the sub-device | |
397 | * at the appropriate moment. | |
398 | */ | |
399 | if (!devres_open_group(component->dev, component, GFP_KERNEL)) { | |
400 | devres_release_group(master->dev, NULL); | |
401 | return -ENOMEM; | |
402 | } | |
403 | ||
404 | dev_dbg(master->dev, "binding %s (ops %ps)\n", | |
405 | dev_name(component->dev), component->ops); | |
406 | ||
407 | ret = component->ops->bind(component->dev, master->dev, data); | |
408 | if (!ret) { | |
409 | component->bound = true; | |
410 | ||
411 | /* | |
412 | * Close the component device's group so that resources | |
413 | * allocated in the binding are encapsulated for removal | |
414 | * at unbind. Remove the group on the DRM device as we | |
415 | * can clean those resources up independently. | |
416 | */ | |
417 | devres_close_group(component->dev, NULL); | |
418 | devres_remove_group(master->dev, NULL); | |
419 | ||
420 | dev_info(master->dev, "bound %s (ops %ps)\n", | |
421 | dev_name(component->dev), component->ops); | |
422 | } else { | |
423 | devres_release_group(component->dev, NULL); | |
424 | devres_release_group(master->dev, NULL); | |
425 | ||
426 | dev_err(master->dev, "failed to bind %s (ops %ps): %d\n", | |
427 | dev_name(component->dev), component->ops, ret); | |
428 | } | |
429 | ||
430 | return ret; | |
431 | } | |
432 | ||
433 | int component_bind_all(struct device *master_dev, void *data) | |
434 | { | |
435 | struct master *master; | |
436 | struct component *c; | |
437 | int ret = 0; | |
438 | ||
439 | WARN_ON(!mutex_is_locked(&component_mutex)); | |
440 | ||
441 | master = __master_find(master_dev, NULL); | |
442 | if (!master) | |
443 | return -EINVAL; | |
444 | ||
445 | list_for_each_entry(c, &master->components, master_node) { | |
446 | ret = component_bind(c, master, data); | |
447 | if (ret) | |
448 | break; | |
449 | } | |
450 | ||
451 | if (ret != 0) { | |
452 | list_for_each_entry_continue_reverse(c, &master->components, | |
453 | master_node) | |
454 | component_unbind(c, master, data); | |
455 | } | |
456 | ||
457 | return ret; | |
458 | } | |
459 | EXPORT_SYMBOL_GPL(component_bind_all); | |
460 | ||
461 | int component_add(struct device *dev, const struct component_ops *ops) | |
462 | { | |
463 | struct component *component; | |
464 | int ret; | |
465 | ||
466 | component = kzalloc(sizeof(*component), GFP_KERNEL); | |
467 | if (!component) | |
468 | return -ENOMEM; | |
469 | ||
470 | component->ops = ops; | |
471 | component->dev = dev; | |
472 | ||
473 | dev_dbg(dev, "adding component (ops %ps)\n", ops); | |
474 | ||
475 | mutex_lock(&component_mutex); | |
476 | list_add_tail(&component->node, &component_list); | |
477 | ||
478 | ret = try_to_bring_up_masters(component); | |
479 | if (ret < 0) { | |
480 | list_del(&component->node); | |
481 | ||
482 | kfree(component); | |
483 | } | |
484 | mutex_unlock(&component_mutex); | |
485 | ||
486 | return ret < 0 ? ret : 0; | |
487 | } | |
488 | EXPORT_SYMBOL_GPL(component_add); | |
489 | ||
490 | void component_del(struct device *dev, const struct component_ops *ops) | |
491 | { | |
492 | struct component *c, *component = NULL; | |
493 | ||
494 | mutex_lock(&component_mutex); | |
495 | list_for_each_entry(c, &component_list, node) | |
496 | if (c->dev == dev && c->ops == ops) { | |
497 | list_del(&c->node); | |
498 | component = c; | |
499 | break; | |
500 | } | |
501 | ||
502 | if (component && component->master) | |
503 | take_down_master(component->master); | |
504 | ||
505 | mutex_unlock(&component_mutex); | |
506 | ||
507 | WARN_ON(!component); | |
508 | kfree(component); | |
509 | } | |
510 | EXPORT_SYMBOL_GPL(component_del); | |
511 | ||
512 | MODULE_LICENSE("GPL v2"); |