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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 | ||
30 | /** | |
31 | * attribute_container_classdev_to_container - given a classdev, return the container | |
32 | * | |
33 | * @classdev: the class device created by attribute_container_add_device. | |
34 | * | |
35 | * Returns the container associated with this classdev. | |
36 | */ | |
37 | struct attribute_container * | |
38 | attribute_container_classdev_to_container(struct class_device *classdev) | |
39 | { | |
40 | struct internal_container *ic = | |
41 | container_of(classdev, struct internal_container, classdev); | |
42 | return ic->cont; | |
43 | } | |
44 | EXPORT_SYMBOL_GPL(attribute_container_classdev_to_container); | |
45 | ||
46 | static struct list_head attribute_container_list; | |
47 | ||
48 | static DECLARE_MUTEX(attribute_container_mutex); | |
49 | ||
50 | /** | |
51 | * attribute_container_register - register an attribute container | |
52 | * | |
53 | * @cont: The container to register. This must be allocated by the | |
54 | * callee and should also be zeroed by it. | |
55 | */ | |
56 | int | |
57 | attribute_container_register(struct attribute_container *cont) | |
58 | { | |
59 | INIT_LIST_HEAD(&cont->node); | |
df4edad1 | 60 | klist_init(&cont->containers); |
1da177e4 LT |
61 | |
62 | down(&attribute_container_mutex); | |
63 | list_add_tail(&cont->node, &attribute_container_list); | |
64 | up(&attribute_container_mutex); | |
65 | ||
66 | return 0; | |
67 | } | |
68 | EXPORT_SYMBOL_GPL(attribute_container_register); | |
69 | ||
70 | /** | |
71 | * attribute_container_unregister - remove a container registration | |
72 | * | |
73 | * @cont: previously registered container to remove | |
74 | */ | |
75 | int | |
76 | attribute_container_unregister(struct attribute_container *cont) | |
77 | { | |
78 | int retval = -EBUSY; | |
79 | down(&attribute_container_mutex); | |
53c165e0 JB |
80 | spin_lock(&cont->containers.k_lock); |
81 | if (!list_empty(&cont->containers.k_list)) | |
1da177e4 LT |
82 | goto out; |
83 | retval = 0; | |
84 | list_del(&cont->node); | |
85 | out: | |
53c165e0 | 86 | spin_unlock(&cont->containers.k_lock); |
1da177e4 LT |
87 | up(&attribute_container_mutex); |
88 | return retval; | |
89 | ||
90 | } | |
91 | EXPORT_SYMBOL_GPL(attribute_container_unregister); | |
92 | ||
93 | /* private function used as class release */ | |
94 | static void attribute_container_release(struct class_device *classdev) | |
95 | { | |
96 | struct internal_container *ic | |
97 | = container_of(classdev, struct internal_container, classdev); | |
98 | struct device *dev = classdev->dev; | |
99 | ||
100 | kfree(ic); | |
101 | put_device(dev); | |
102 | } | |
103 | ||
104 | /** | |
105 | * attribute_container_add_device - see if any container is interested in dev | |
106 | * | |
107 | * @dev: device to add attributes to | |
108 | * @fn: function to trigger addition of class device. | |
109 | * | |
110 | * This function allocates storage for the class device(s) to be | |
111 | * attached to dev (one for each matching attribute_container). If no | |
112 | * fn is provided, the code will simply register the class device via | |
113 | * class_device_add. If a function is provided, it is expected to add | |
114 | * the class device at the appropriate time. One of the things that | |
115 | * might be necessary is to allocate and initialise the classdev and | |
116 | * then add it a later time. To do this, call this routine for | |
117 | * allocation and initialisation and then use | |
118 | * attribute_container_device_trigger() to call class_device_add() on | |
119 | * it. Note: after this, the class device contains a reference to dev | |
120 | * which is not relinquished until the release of the classdev. | |
121 | */ | |
122 | void | |
123 | attribute_container_add_device(struct device *dev, | |
124 | int (*fn)(struct attribute_container *, | |
125 | struct device *, | |
126 | struct class_device *)) | |
127 | { | |
128 | struct attribute_container *cont; | |
129 | ||
130 | down(&attribute_container_mutex); | |
131 | list_for_each_entry(cont, &attribute_container_list, node) { | |
132 | struct internal_container *ic; | |
133 | ||
134 | if (attribute_container_no_classdevs(cont)) | |
135 | continue; | |
136 | ||
137 | if (!cont->match(cont, dev)) | |
138 | continue; | |
139 | ic = kmalloc(sizeof(struct internal_container), GFP_KERNEL); | |
140 | if (!ic) { | |
141 | dev_printk(KERN_ERR, dev, "failed to allocate class container\n"); | |
142 | continue; | |
143 | } | |
144 | memset(ic, 0, sizeof(struct internal_container)); | |
1da177e4 LT |
145 | ic->cont = cont; |
146 | class_device_initialize(&ic->classdev); | |
147 | ic->classdev.dev = get_device(dev); | |
148 | ic->classdev.class = cont->class; | |
149 | cont->class->release = attribute_container_release; | |
150 | strcpy(ic->classdev.class_id, dev->bus_id); | |
151 | if (fn) | |
152 | fn(cont, dev, &ic->classdev); | |
153 | else | |
154 | attribute_container_add_class_device(&ic->classdev); | |
53c165e0 | 155 | klist_add_tail(&ic->node, &cont->containers); |
1da177e4 LT |
156 | } |
157 | up(&attribute_container_mutex); | |
158 | } | |
159 | ||
53c165e0 JB |
160 | /* FIXME: can't break out of this unless klist_iter_exit is also |
161 | * called before doing the break | |
162 | */ | |
163 | #define klist_for_each_entry(pos, head, member, iter) \ | |
164 | for (klist_iter_init(head, iter); (pos = ({ \ | |
165 | struct klist_node *n = klist_next(iter); \ | |
df4edad1 LT |
166 | n ? ({ klist_iter_exit(iter) ; NULL; }) : \ |
167 | container_of(n, typeof(*pos), member);\ | |
53c165e0 JB |
168 | }) ) != NULL; ) |
169 | ||
170 | ||
1da177e4 LT |
171 | /** |
172 | * attribute_container_remove_device - make device eligible for removal. | |
173 | * | |
174 | * @dev: The generic device | |
175 | * @fn: A function to call to remove the device | |
176 | * | |
177 | * This routine triggers device removal. If fn is NULL, then it is | |
178 | * simply done via class_device_unregister (note that if something | |
179 | * still has a reference to the classdev, then the memory occupied | |
180 | * will not be freed until the classdev is released). If you want a | |
181 | * two phase release: remove from visibility and then delete the | |
182 | * device, then you should use this routine with a fn that calls | |
183 | * class_device_del() and then use | |
184 | * attribute_container_device_trigger() to do the final put on the | |
185 | * classdev. | |
186 | */ | |
187 | void | |
188 | attribute_container_remove_device(struct device *dev, | |
189 | void (*fn)(struct attribute_container *, | |
190 | struct device *, | |
191 | struct class_device *)) | |
192 | { | |
193 | struct attribute_container *cont; | |
194 | ||
195 | down(&attribute_container_mutex); | |
196 | list_for_each_entry(cont, &attribute_container_list, node) { | |
53c165e0 JB |
197 | struct internal_container *ic; |
198 | struct klist_iter iter; | |
1da177e4 LT |
199 | |
200 | if (attribute_container_no_classdevs(cont)) | |
201 | continue; | |
202 | ||
203 | if (!cont->match(cont, dev)) | |
204 | continue; | |
53c165e0 JB |
205 | |
206 | klist_for_each_entry(ic, &cont->containers, node, &iter) { | |
1da177e4 LT |
207 | if (dev != ic->classdev.dev) |
208 | continue; | |
df4edad1 | 209 | klist_remove(&ic->node); |
1da177e4 LT |
210 | if (fn) |
211 | fn(cont, dev, &ic->classdev); | |
212 | else { | |
213 | attribute_container_remove_attrs(&ic->classdev); | |
214 | class_device_unregister(&ic->classdev); | |
215 | } | |
216 | } | |
217 | } | |
218 | up(&attribute_container_mutex); | |
219 | } | |
220 | EXPORT_SYMBOL_GPL(attribute_container_remove_device); | |
221 | ||
222 | /** | |
223 | * attribute_container_device_trigger - execute a trigger for each matching classdev | |
224 | * | |
225 | * @dev: The generic device to run the trigger for | |
226 | * @fn the function to execute for each classdev. | |
227 | * | |
228 | * This funcion is for executing a trigger when you need to know both | |
229 | * the container and the classdev. If you only care about the | |
230 | * container, then use attribute_container_trigger() instead. | |
231 | */ | |
232 | void | |
233 | attribute_container_device_trigger(struct device *dev, | |
234 | int (*fn)(struct attribute_container *, | |
235 | struct device *, | |
236 | struct class_device *)) | |
237 | { | |
238 | struct attribute_container *cont; | |
239 | ||
240 | down(&attribute_container_mutex); | |
241 | list_for_each_entry(cont, &attribute_container_list, node) { | |
53c165e0 JB |
242 | struct internal_container *ic; |
243 | struct klist_iter iter; | |
1da177e4 LT |
244 | |
245 | if (!cont->match(cont, dev)) | |
246 | continue; | |
247 | ||
ebd8bb76 JB |
248 | if (attribute_container_no_classdevs(cont)) { |
249 | fn(cont, dev, NULL); | |
250 | continue; | |
251 | } | |
252 | ||
53c165e0 | 253 | klist_for_each_entry(ic, &cont->containers, node, &iter) { |
1da177e4 LT |
254 | if (dev == ic->classdev.dev) |
255 | fn(cont, dev, &ic->classdev); | |
256 | } | |
257 | } | |
258 | up(&attribute_container_mutex); | |
259 | } | |
260 | EXPORT_SYMBOL_GPL(attribute_container_device_trigger); | |
261 | ||
262 | /** | |
263 | * attribute_container_trigger - trigger a function for each matching container | |
264 | * | |
265 | * @dev: The generic device to activate the trigger for | |
266 | * @fn: the function to trigger | |
267 | * | |
268 | * This routine triggers a function that only needs to know the | |
269 | * matching containers (not the classdev) associated with a device. | |
270 | * It is more lightweight than attribute_container_device_trigger, so | |
271 | * should be used in preference unless the triggering function | |
272 | * actually needs to know the classdev. | |
273 | */ | |
274 | void | |
275 | attribute_container_trigger(struct device *dev, | |
276 | int (*fn)(struct attribute_container *, | |
277 | struct device *)) | |
278 | { | |
279 | struct attribute_container *cont; | |
280 | ||
281 | down(&attribute_container_mutex); | |
282 | list_for_each_entry(cont, &attribute_container_list, node) { | |
283 | if (cont->match(cont, dev)) | |
284 | fn(cont, dev); | |
285 | } | |
286 | up(&attribute_container_mutex); | |
287 | } | |
288 | EXPORT_SYMBOL_GPL(attribute_container_trigger); | |
289 | ||
290 | /** | |
291 | * attribute_container_add_attrs - add attributes | |
292 | * | |
293 | * @classdev: The class device | |
294 | * | |
295 | * This simply creates all the class device sysfs files from the | |
296 | * attributes listed in the container | |
297 | */ | |
298 | int | |
299 | attribute_container_add_attrs(struct class_device *classdev) | |
300 | { | |
301 | struct attribute_container *cont = | |
302 | attribute_container_classdev_to_container(classdev); | |
303 | struct class_device_attribute **attrs = cont->attrs; | |
304 | int i, error; | |
305 | ||
306 | if (!attrs) | |
307 | return 0; | |
308 | ||
309 | for (i = 0; attrs[i]; i++) { | |
310 | error = class_device_create_file(classdev, attrs[i]); | |
311 | if (error) | |
312 | return error; | |
313 | } | |
314 | ||
315 | return 0; | |
316 | } | |
317 | EXPORT_SYMBOL_GPL(attribute_container_add_attrs); | |
318 | ||
319 | /** | |
320 | * attribute_container_add_class_device - same function as class_device_add | |
321 | * | |
322 | * @classdev: the class device to add | |
323 | * | |
324 | * This performs essentially the same function as class_device_add except for | |
325 | * attribute containers, namely add the classdev to the system and then | |
326 | * create the attribute files | |
327 | */ | |
328 | int | |
329 | attribute_container_add_class_device(struct class_device *classdev) | |
330 | { | |
331 | int error = class_device_add(classdev); | |
332 | if (error) | |
333 | return error; | |
334 | return attribute_container_add_attrs(classdev); | |
335 | } | |
336 | EXPORT_SYMBOL_GPL(attribute_container_add_class_device); | |
337 | ||
338 | /** | |
339 | * attribute_container_add_class_device_adapter - simple adapter for triggers | |
340 | * | |
341 | * This function is identical to attribute_container_add_class_device except | |
342 | * that it is designed to be called from the triggers | |
343 | */ | |
344 | int | |
345 | attribute_container_add_class_device_adapter(struct attribute_container *cont, | |
346 | struct device *dev, | |
347 | struct class_device *classdev) | |
348 | { | |
349 | return attribute_container_add_class_device(classdev); | |
350 | } | |
351 | EXPORT_SYMBOL_GPL(attribute_container_add_class_device_adapter); | |
352 | ||
353 | /** | |
354 | * attribute_container_remove_attrs - remove any attribute files | |
355 | * | |
356 | * @classdev: The class device to remove the files from | |
357 | * | |
358 | */ | |
359 | void | |
360 | attribute_container_remove_attrs(struct class_device *classdev) | |
361 | { | |
362 | struct attribute_container *cont = | |
363 | attribute_container_classdev_to_container(classdev); | |
364 | struct class_device_attribute **attrs = cont->attrs; | |
365 | int i; | |
366 | ||
367 | if (!attrs) | |
368 | return; | |
369 | ||
370 | for (i = 0; attrs[i]; i++) | |
371 | class_device_remove_file(classdev, attrs[i]); | |
372 | } | |
373 | EXPORT_SYMBOL_GPL(attribute_container_remove_attrs); | |
374 | ||
375 | /** | |
376 | * attribute_container_class_device_del - equivalent of class_device_del | |
377 | * | |
378 | * @classdev: the class device | |
379 | * | |
380 | * This function simply removes all the attribute files and then calls | |
381 | * class_device_del. | |
382 | */ | |
383 | void | |
384 | attribute_container_class_device_del(struct class_device *classdev) | |
385 | { | |
386 | attribute_container_remove_attrs(classdev); | |
387 | class_device_del(classdev); | |
388 | } | |
389 | EXPORT_SYMBOL_GPL(attribute_container_class_device_del); | |
390 | ||
d0a7e574 JB |
391 | /** |
392 | * attribute_container_find_class_device - find the corresponding class_device | |
393 | * | |
394 | * @cont: the container | |
395 | * @dev: the generic device | |
396 | * | |
397 | * Looks up the device in the container's list of class devices and returns | |
398 | * the corresponding class_device. | |
399 | */ | |
400 | struct class_device * | |
401 | attribute_container_find_class_device(struct attribute_container *cont, | |
402 | struct device *dev) | |
403 | { | |
404 | struct class_device *cdev = NULL; | |
405 | struct internal_container *ic; | |
53c165e0 | 406 | struct klist_iter iter; |
d0a7e574 | 407 | |
53c165e0 | 408 | klist_for_each_entry(ic, &cont->containers, node, &iter) { |
d0a7e574 JB |
409 | if (ic->classdev.dev == dev) { |
410 | cdev = &ic->classdev; | |
53c165e0 JB |
411 | /* FIXME: must exit iterator then break */ |
412 | klist_iter_exit(&iter); | |
d0a7e574 JB |
413 | break; |
414 | } | |
415 | } | |
d0a7e574 JB |
416 | |
417 | return cdev; | |
418 | } | |
419 | EXPORT_SYMBOL_GPL(attribute_container_find_class_device); | |
420 | ||
1da177e4 LT |
421 | int __init |
422 | attribute_container_init(void) | |
423 | { | |
424 | INIT_LIST_HEAD(&attribute_container_list); | |
425 | return 0; | |
426 | } |