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1da177e4 LT |
1 | /* |
2 | * attribute_container.c - implementation of a simple container for classes | |
3 | * | |
4 | * Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com> | |
5 | * | |
6 | * This file is licensed under GPLv2 | |
7 | * | |
8 | * The basic idea here is to enable a device to be attached to an | |
9 | * aritrary numer of classes without having to allocate storage for them. | |
10 | * Instead, the contained classes select the devices they need to attach | |
11 | * to via a matching function. | |
12 | */ | |
13 | ||
14 | #include <linux/attribute_container.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/device.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/list.h> | |
20 | #include <linux/module.h> | |
21 | ||
a1bdc7aa BD |
22 | #include "base.h" |
23 | ||
1da177e4 LT |
24 | /* This is a private structure used to tie the classdev and the |
25 | * container .. it should never be visible outside this file */ | |
26 | struct internal_container { | |
53c165e0 | 27 | struct klist_node node; |
1da177e4 LT |
28 | struct attribute_container *cont; |
29 | struct class_device classdev; | |
30 | }; | |
31 | ||
caf39e87 LT |
32 | static void internal_container_klist_get(struct klist_node *n) |
33 | { | |
34 | struct internal_container *ic = | |
35 | container_of(n, struct internal_container, node); | |
36 | class_device_get(&ic->classdev); | |
37 | } | |
38 | ||
39 | static void internal_container_klist_put(struct klist_node *n) | |
40 | { | |
41 | struct internal_container *ic = | |
42 | container_of(n, struct internal_container, node); | |
43 | class_device_put(&ic->classdev); | |
44 | } | |
45 | ||
46 | ||
1da177e4 LT |
47 | /** |
48 | * attribute_container_classdev_to_container - given a classdev, return the container | |
49 | * | |
50 | * @classdev: the class device created by attribute_container_add_device. | |
51 | * | |
52 | * Returns the container associated with this classdev. | |
53 | */ | |
54 | struct attribute_container * | |
55 | attribute_container_classdev_to_container(struct class_device *classdev) | |
56 | { | |
57 | struct internal_container *ic = | |
58 | container_of(classdev, struct internal_container, classdev); | |
59 | return ic->cont; | |
60 | } | |
61 | EXPORT_SYMBOL_GPL(attribute_container_classdev_to_container); | |
62 | ||
63 | static struct list_head attribute_container_list; | |
64 | ||
65 | static DECLARE_MUTEX(attribute_container_mutex); | |
66 | ||
67 | /** | |
68 | * attribute_container_register - register an attribute container | |
69 | * | |
70 | * @cont: The container to register. This must be allocated by the | |
71 | * callee and should also be zeroed by it. | |
72 | */ | |
73 | int | |
74 | attribute_container_register(struct attribute_container *cont) | |
75 | { | |
76 | INIT_LIST_HEAD(&cont->node); | |
caf39e87 LT |
77 | klist_init(&cont->containers,internal_container_klist_get, |
78 | internal_container_klist_put); | |
1da177e4 LT |
79 | |
80 | down(&attribute_container_mutex); | |
81 | list_add_tail(&cont->node, &attribute_container_list); | |
82 | up(&attribute_container_mutex); | |
83 | ||
84 | return 0; | |
85 | } | |
86 | EXPORT_SYMBOL_GPL(attribute_container_register); | |
87 | ||
88 | /** | |
89 | * attribute_container_unregister - remove a container registration | |
90 | * | |
91 | * @cont: previously registered container to remove | |
92 | */ | |
93 | int | |
94 | attribute_container_unregister(struct attribute_container *cont) | |
95 | { | |
96 | int retval = -EBUSY; | |
97 | down(&attribute_container_mutex); | |
53c165e0 JB |
98 | spin_lock(&cont->containers.k_lock); |
99 | if (!list_empty(&cont->containers.k_list)) | |
1da177e4 LT |
100 | goto out; |
101 | retval = 0; | |
102 | list_del(&cont->node); | |
103 | out: | |
53c165e0 | 104 | spin_unlock(&cont->containers.k_lock); |
1da177e4 LT |
105 | up(&attribute_container_mutex); |
106 | return retval; | |
107 | ||
108 | } | |
109 | EXPORT_SYMBOL_GPL(attribute_container_unregister); | |
110 | ||
111 | /* private function used as class release */ | |
112 | static void attribute_container_release(struct class_device *classdev) | |
113 | { | |
114 | struct internal_container *ic | |
115 | = container_of(classdev, struct internal_container, classdev); | |
116 | struct device *dev = classdev->dev; | |
117 | ||
118 | kfree(ic); | |
119 | put_device(dev); | |
120 | } | |
121 | ||
122 | /** | |
123 | * attribute_container_add_device - see if any container is interested in dev | |
124 | * | |
125 | * @dev: device to add attributes to | |
126 | * @fn: function to trigger addition of class device. | |
127 | * | |
128 | * This function allocates storage for the class device(s) to be | |
129 | * attached to dev (one for each matching attribute_container). If no | |
130 | * fn is provided, the code will simply register the class device via | |
131 | * class_device_add. If a function is provided, it is expected to add | |
132 | * the class device at the appropriate time. One of the things that | |
133 | * might be necessary is to allocate and initialise the classdev and | |
134 | * then add it a later time. To do this, call this routine for | |
135 | * allocation and initialisation and then use | |
136 | * attribute_container_device_trigger() to call class_device_add() on | |
137 | * it. Note: after this, the class device contains a reference to dev | |
138 | * which is not relinquished until the release of the classdev. | |
139 | */ | |
140 | void | |
141 | attribute_container_add_device(struct device *dev, | |
142 | int (*fn)(struct attribute_container *, | |
143 | struct device *, | |
144 | struct class_device *)) | |
145 | { | |
146 | struct attribute_container *cont; | |
147 | ||
148 | down(&attribute_container_mutex); | |
149 | list_for_each_entry(cont, &attribute_container_list, node) { | |
150 | struct internal_container *ic; | |
151 | ||
152 | if (attribute_container_no_classdevs(cont)) | |
153 | continue; | |
154 | ||
155 | if (!cont->match(cont, dev)) | |
156 | continue; | |
4aed0644 JS |
157 | |
158 | ic = kzalloc(sizeof(*ic), GFP_KERNEL); | |
1da177e4 LT |
159 | if (!ic) { |
160 | dev_printk(KERN_ERR, dev, "failed to allocate class container\n"); | |
161 | continue; | |
162 | } | |
4aed0644 | 163 | |
1da177e4 LT |
164 | ic->cont = cont; |
165 | class_device_initialize(&ic->classdev); | |
166 | ic->classdev.dev = get_device(dev); | |
167 | ic->classdev.class = cont->class; | |
168 | cont->class->release = attribute_container_release; | |
169 | strcpy(ic->classdev.class_id, dev->bus_id); | |
170 | if (fn) | |
171 | fn(cont, dev, &ic->classdev); | |
172 | else | |
173 | attribute_container_add_class_device(&ic->classdev); | |
53c165e0 | 174 | klist_add_tail(&ic->node, &cont->containers); |
1da177e4 LT |
175 | } |
176 | up(&attribute_container_mutex); | |
177 | } | |
178 | ||
53c165e0 JB |
179 | /* FIXME: can't break out of this unless klist_iter_exit is also |
180 | * called before doing the break | |
181 | */ | |
182 | #define klist_for_each_entry(pos, head, member, iter) \ | |
183 | for (klist_iter_init(head, iter); (pos = ({ \ | |
184 | struct klist_node *n = klist_next(iter); \ | |
caf39e87 LT |
185 | n ? container_of(n, typeof(*pos), member) : \ |
186 | ({ klist_iter_exit(iter) ; NULL; }); \ | |
53c165e0 JB |
187 | }) ) != NULL; ) |
188 | ||
189 | ||
1da177e4 LT |
190 | /** |
191 | * attribute_container_remove_device - make device eligible for removal. | |
192 | * | |
193 | * @dev: The generic device | |
194 | * @fn: A function to call to remove the device | |
195 | * | |
196 | * This routine triggers device removal. If fn is NULL, then it is | |
197 | * simply done via class_device_unregister (note that if something | |
198 | * still has a reference to the classdev, then the memory occupied | |
199 | * will not be freed until the classdev is released). If you want a | |
200 | * two phase release: remove from visibility and then delete the | |
201 | * device, then you should use this routine with a fn that calls | |
202 | * class_device_del() and then use | |
203 | * attribute_container_device_trigger() to do the final put on the | |
204 | * classdev. | |
205 | */ | |
206 | void | |
207 | attribute_container_remove_device(struct device *dev, | |
208 | void (*fn)(struct attribute_container *, | |
209 | struct device *, | |
210 | struct class_device *)) | |
211 | { | |
212 | struct attribute_container *cont; | |
213 | ||
214 | down(&attribute_container_mutex); | |
215 | list_for_each_entry(cont, &attribute_container_list, node) { | |
53c165e0 JB |
216 | struct internal_container *ic; |
217 | struct klist_iter iter; | |
1da177e4 LT |
218 | |
219 | if (attribute_container_no_classdevs(cont)) | |
220 | continue; | |
221 | ||
222 | if (!cont->match(cont, dev)) | |
223 | continue; | |
53c165e0 JB |
224 | |
225 | klist_for_each_entry(ic, &cont->containers, node, &iter) { | |
1da177e4 LT |
226 | if (dev != ic->classdev.dev) |
227 | continue; | |
caf39e87 | 228 | klist_del(&ic->node); |
1da177e4 LT |
229 | if (fn) |
230 | fn(cont, dev, &ic->classdev); | |
231 | else { | |
232 | attribute_container_remove_attrs(&ic->classdev); | |
233 | class_device_unregister(&ic->classdev); | |
234 | } | |
235 | } | |
236 | } | |
237 | up(&attribute_container_mutex); | |
238 | } | |
239 | EXPORT_SYMBOL_GPL(attribute_container_remove_device); | |
240 | ||
241 | /** | |
242 | * attribute_container_device_trigger - execute a trigger for each matching classdev | |
243 | * | |
244 | * @dev: The generic device to run the trigger for | |
245 | * @fn the function to execute for each classdev. | |
246 | * | |
247 | * This funcion is for executing a trigger when you need to know both | |
248 | * the container and the classdev. If you only care about the | |
249 | * container, then use attribute_container_trigger() instead. | |
250 | */ | |
251 | void | |
252 | attribute_container_device_trigger(struct device *dev, | |
253 | int (*fn)(struct attribute_container *, | |
254 | struct device *, | |
255 | struct class_device *)) | |
256 | { | |
257 | struct attribute_container *cont; | |
258 | ||
259 | down(&attribute_container_mutex); | |
260 | list_for_each_entry(cont, &attribute_container_list, node) { | |
53c165e0 JB |
261 | struct internal_container *ic; |
262 | struct klist_iter iter; | |
1da177e4 LT |
263 | |
264 | if (!cont->match(cont, dev)) | |
265 | continue; | |
266 | ||
ebd8bb76 JB |
267 | if (attribute_container_no_classdevs(cont)) { |
268 | fn(cont, dev, NULL); | |
269 | continue; | |
270 | } | |
271 | ||
53c165e0 | 272 | klist_for_each_entry(ic, &cont->containers, node, &iter) { |
1da177e4 LT |
273 | if (dev == ic->classdev.dev) |
274 | fn(cont, dev, &ic->classdev); | |
275 | } | |
276 | } | |
277 | up(&attribute_container_mutex); | |
278 | } | |
279 | EXPORT_SYMBOL_GPL(attribute_container_device_trigger); | |
280 | ||
281 | /** | |
282 | * attribute_container_trigger - trigger a function for each matching container | |
283 | * | |
284 | * @dev: The generic device to activate the trigger for | |
285 | * @fn: the function to trigger | |
286 | * | |
287 | * This routine triggers a function that only needs to know the | |
288 | * matching containers (not the classdev) associated with a device. | |
289 | * It is more lightweight than attribute_container_device_trigger, so | |
290 | * should be used in preference unless the triggering function | |
291 | * actually needs to know the classdev. | |
292 | */ | |
293 | void | |
294 | attribute_container_trigger(struct device *dev, | |
295 | int (*fn)(struct attribute_container *, | |
296 | struct device *)) | |
297 | { | |
298 | struct attribute_container *cont; | |
299 | ||
300 | down(&attribute_container_mutex); | |
301 | list_for_each_entry(cont, &attribute_container_list, node) { | |
302 | if (cont->match(cont, dev)) | |
303 | fn(cont, dev); | |
304 | } | |
305 | up(&attribute_container_mutex); | |
306 | } | |
307 | EXPORT_SYMBOL_GPL(attribute_container_trigger); | |
308 | ||
309 | /** | |
310 | * attribute_container_add_attrs - add attributes | |
311 | * | |
312 | * @classdev: The class device | |
313 | * | |
314 | * This simply creates all the class device sysfs files from the | |
315 | * attributes listed in the container | |
316 | */ | |
317 | int | |
318 | attribute_container_add_attrs(struct class_device *classdev) | |
319 | { | |
320 | struct attribute_container *cont = | |
321 | attribute_container_classdev_to_container(classdev); | |
322 | struct class_device_attribute **attrs = cont->attrs; | |
323 | int i, error; | |
324 | ||
325 | if (!attrs) | |
326 | return 0; | |
327 | ||
328 | for (i = 0; attrs[i]; i++) { | |
329 | error = class_device_create_file(classdev, attrs[i]); | |
330 | if (error) | |
331 | return error; | |
332 | } | |
333 | ||
334 | return 0; | |
335 | } | |
336 | EXPORT_SYMBOL_GPL(attribute_container_add_attrs); | |
337 | ||
338 | /** | |
339 | * attribute_container_add_class_device - same function as class_device_add | |
340 | * | |
341 | * @classdev: the class device to add | |
342 | * | |
343 | * This performs essentially the same function as class_device_add except for | |
344 | * attribute containers, namely add the classdev to the system and then | |
345 | * create the attribute files | |
346 | */ | |
347 | int | |
348 | attribute_container_add_class_device(struct class_device *classdev) | |
349 | { | |
350 | int error = class_device_add(classdev); | |
351 | if (error) | |
352 | return error; | |
353 | return attribute_container_add_attrs(classdev); | |
354 | } | |
355 | EXPORT_SYMBOL_GPL(attribute_container_add_class_device); | |
356 | ||
357 | /** | |
358 | * attribute_container_add_class_device_adapter - simple adapter for triggers | |
359 | * | |
360 | * This function is identical to attribute_container_add_class_device except | |
361 | * that it is designed to be called from the triggers | |
362 | */ | |
363 | int | |
364 | attribute_container_add_class_device_adapter(struct attribute_container *cont, | |
365 | struct device *dev, | |
366 | struct class_device *classdev) | |
367 | { | |
368 | return attribute_container_add_class_device(classdev); | |
369 | } | |
370 | EXPORT_SYMBOL_GPL(attribute_container_add_class_device_adapter); | |
371 | ||
372 | /** | |
373 | * attribute_container_remove_attrs - remove any attribute files | |
374 | * | |
375 | * @classdev: The class device to remove the files from | |
376 | * | |
377 | */ | |
378 | void | |
379 | attribute_container_remove_attrs(struct class_device *classdev) | |
380 | { | |
381 | struct attribute_container *cont = | |
382 | attribute_container_classdev_to_container(classdev); | |
383 | struct class_device_attribute **attrs = cont->attrs; | |
384 | int i; | |
385 | ||
386 | if (!attrs) | |
387 | return; | |
388 | ||
389 | for (i = 0; attrs[i]; i++) | |
390 | class_device_remove_file(classdev, attrs[i]); | |
391 | } | |
392 | EXPORT_SYMBOL_GPL(attribute_container_remove_attrs); | |
393 | ||
394 | /** | |
395 | * attribute_container_class_device_del - equivalent of class_device_del | |
396 | * | |
397 | * @classdev: the class device | |
398 | * | |
399 | * This function simply removes all the attribute files and then calls | |
400 | * class_device_del. | |
401 | */ | |
402 | void | |
403 | attribute_container_class_device_del(struct class_device *classdev) | |
404 | { | |
405 | attribute_container_remove_attrs(classdev); | |
406 | class_device_del(classdev); | |
407 | } | |
408 | EXPORT_SYMBOL_GPL(attribute_container_class_device_del); | |
409 | ||
d0a7e574 JB |
410 | /** |
411 | * attribute_container_find_class_device - find the corresponding class_device | |
412 | * | |
413 | * @cont: the container | |
414 | * @dev: the generic device | |
415 | * | |
416 | * Looks up the device in the container's list of class devices and returns | |
417 | * the corresponding class_device. | |
418 | */ | |
419 | struct class_device * | |
420 | attribute_container_find_class_device(struct attribute_container *cont, | |
421 | struct device *dev) | |
422 | { | |
423 | struct class_device *cdev = NULL; | |
424 | struct internal_container *ic; | |
53c165e0 | 425 | struct klist_iter iter; |
d0a7e574 | 426 | |
53c165e0 | 427 | klist_for_each_entry(ic, &cont->containers, node, &iter) { |
d0a7e574 JB |
428 | if (ic->classdev.dev == dev) { |
429 | cdev = &ic->classdev; | |
53c165e0 JB |
430 | /* FIXME: must exit iterator then break */ |
431 | klist_iter_exit(&iter); | |
d0a7e574 JB |
432 | break; |
433 | } | |
434 | } | |
d0a7e574 JB |
435 | |
436 | return cdev; | |
437 | } | |
438 | EXPORT_SYMBOL_GPL(attribute_container_find_class_device); | |
439 | ||
1da177e4 LT |
440 | int __init |
441 | attribute_container_init(void) | |
442 | { | |
443 | INIT_LIST_HEAD(&attribute_container_list); | |
444 | return 0; | |
445 | } |