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