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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 { | |
25 | struct list_head node; | |
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); | |
60 | INIT_LIST_HEAD(&cont->containers); | |
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); | |
80 | if (!list_empty(&cont->containers)) | |
81 | goto out; | |
82 | retval = 0; | |
83 | list_del(&cont->node); | |
84 | out: | |
85 | up(&attribute_container_mutex); | |
86 | return retval; | |
87 | ||
88 | } | |
89 | EXPORT_SYMBOL_GPL(attribute_container_unregister); | |
90 | ||
91 | /* private function used as class release */ | |
92 | static void attribute_container_release(struct class_device *classdev) | |
93 | { | |
94 | struct internal_container *ic | |
95 | = container_of(classdev, struct internal_container, classdev); | |
96 | struct device *dev = classdev->dev; | |
97 | ||
98 | kfree(ic); | |
99 | put_device(dev); | |
100 | } | |
101 | ||
102 | /** | |
103 | * attribute_container_add_device - see if any container is interested in dev | |
104 | * | |
105 | * @dev: device to add attributes to | |
106 | * @fn: function to trigger addition of class device. | |
107 | * | |
108 | * This function allocates storage for the class device(s) to be | |
109 | * attached to dev (one for each matching attribute_container). If no | |
110 | * fn is provided, the code will simply register the class device via | |
111 | * class_device_add. If a function is provided, it is expected to add | |
112 | * the class device at the appropriate time. One of the things that | |
113 | * might be necessary is to allocate and initialise the classdev and | |
114 | * then add it a later time. To do this, call this routine for | |
115 | * allocation and initialisation and then use | |
116 | * attribute_container_device_trigger() to call class_device_add() on | |
117 | * it. Note: after this, the class device contains a reference to dev | |
118 | * which is not relinquished until the release of the classdev. | |
119 | */ | |
120 | void | |
121 | attribute_container_add_device(struct device *dev, | |
122 | int (*fn)(struct attribute_container *, | |
123 | struct device *, | |
124 | struct class_device *)) | |
125 | { | |
126 | struct attribute_container *cont; | |
127 | ||
128 | down(&attribute_container_mutex); | |
129 | list_for_each_entry(cont, &attribute_container_list, node) { | |
130 | struct internal_container *ic; | |
131 | ||
132 | if (attribute_container_no_classdevs(cont)) | |
133 | continue; | |
134 | ||
135 | if (!cont->match(cont, dev)) | |
136 | continue; | |
137 | ic = kmalloc(sizeof(struct internal_container), GFP_KERNEL); | |
138 | if (!ic) { | |
139 | dev_printk(KERN_ERR, dev, "failed to allocate class container\n"); | |
140 | continue; | |
141 | } | |
142 | memset(ic, 0, sizeof(struct internal_container)); | |
143 | INIT_LIST_HEAD(&ic->node); | |
144 | ic->cont = cont; | |
145 | class_device_initialize(&ic->classdev); | |
146 | ic->classdev.dev = get_device(dev); | |
147 | ic->classdev.class = cont->class; | |
148 | cont->class->release = attribute_container_release; | |
149 | strcpy(ic->classdev.class_id, dev->bus_id); | |
150 | if (fn) | |
151 | fn(cont, dev, &ic->classdev); | |
152 | else | |
153 | attribute_container_add_class_device(&ic->classdev); | |
154 | list_add_tail(&ic->node, &cont->containers); | |
155 | } | |
156 | up(&attribute_container_mutex); | |
157 | } | |
158 | ||
159 | /** | |
160 | * attribute_container_remove_device - make device eligible for removal. | |
161 | * | |
162 | * @dev: The generic device | |
163 | * @fn: A function to call to remove the device | |
164 | * | |
165 | * This routine triggers device removal. If fn is NULL, then it is | |
166 | * simply done via class_device_unregister (note that if something | |
167 | * still has a reference to the classdev, then the memory occupied | |
168 | * will not be freed until the classdev is released). If you want a | |
169 | * two phase release: remove from visibility and then delete the | |
170 | * device, then you should use this routine with a fn that calls | |
171 | * class_device_del() and then use | |
172 | * attribute_container_device_trigger() to do the final put on the | |
173 | * classdev. | |
174 | */ | |
175 | void | |
176 | attribute_container_remove_device(struct device *dev, | |
177 | void (*fn)(struct attribute_container *, | |
178 | struct device *, | |
179 | struct class_device *)) | |
180 | { | |
181 | struct attribute_container *cont; | |
182 | ||
183 | down(&attribute_container_mutex); | |
184 | list_for_each_entry(cont, &attribute_container_list, node) { | |
185 | struct internal_container *ic, *tmp; | |
186 | ||
187 | if (attribute_container_no_classdevs(cont)) | |
188 | continue; | |
189 | ||
190 | if (!cont->match(cont, dev)) | |
191 | continue; | |
192 | list_for_each_entry_safe(ic, tmp, &cont->containers, node) { | |
193 | if (dev != ic->classdev.dev) | |
194 | continue; | |
195 | list_del(&ic->node); | |
196 | if (fn) | |
197 | fn(cont, dev, &ic->classdev); | |
198 | else { | |
199 | attribute_container_remove_attrs(&ic->classdev); | |
200 | class_device_unregister(&ic->classdev); | |
201 | } | |
202 | } | |
203 | } | |
204 | up(&attribute_container_mutex); | |
205 | } | |
206 | EXPORT_SYMBOL_GPL(attribute_container_remove_device); | |
207 | ||
208 | /** | |
209 | * attribute_container_device_trigger - execute a trigger for each matching classdev | |
210 | * | |
211 | * @dev: The generic device to run the trigger for | |
212 | * @fn the function to execute for each classdev. | |
213 | * | |
214 | * This funcion is for executing a trigger when you need to know both | |
215 | * the container and the classdev. If you only care about the | |
216 | * container, then use attribute_container_trigger() instead. | |
217 | */ | |
218 | void | |
219 | attribute_container_device_trigger(struct device *dev, | |
220 | int (*fn)(struct attribute_container *, | |
221 | struct device *, | |
222 | struct class_device *)) | |
223 | { | |
224 | struct attribute_container *cont; | |
225 | ||
226 | down(&attribute_container_mutex); | |
227 | list_for_each_entry(cont, &attribute_container_list, node) { | |
228 | struct internal_container *ic, *tmp; | |
229 | ||
230 | if (!cont->match(cont, dev)) | |
231 | continue; | |
232 | ||
233 | list_for_each_entry_safe(ic, tmp, &cont->containers, node) { | |
234 | if (dev == ic->classdev.dev) | |
235 | fn(cont, dev, &ic->classdev); | |
236 | } | |
237 | } | |
238 | up(&attribute_container_mutex); | |
239 | } | |
240 | EXPORT_SYMBOL_GPL(attribute_container_device_trigger); | |
241 | ||
242 | /** | |
243 | * attribute_container_trigger - trigger a function for each matching container | |
244 | * | |
245 | * @dev: The generic device to activate the trigger for | |
246 | * @fn: the function to trigger | |
247 | * | |
248 | * This routine triggers a function that only needs to know the | |
249 | * matching containers (not the classdev) associated with a device. | |
250 | * It is more lightweight than attribute_container_device_trigger, so | |
251 | * should be used in preference unless the triggering function | |
252 | * actually needs to know the classdev. | |
253 | */ | |
254 | void | |
255 | attribute_container_trigger(struct device *dev, | |
256 | int (*fn)(struct attribute_container *, | |
257 | struct device *)) | |
258 | { | |
259 | struct attribute_container *cont; | |
260 | ||
261 | down(&attribute_container_mutex); | |
262 | list_for_each_entry(cont, &attribute_container_list, node) { | |
263 | if (cont->match(cont, dev)) | |
264 | fn(cont, dev); | |
265 | } | |
266 | up(&attribute_container_mutex); | |
267 | } | |
268 | EXPORT_SYMBOL_GPL(attribute_container_trigger); | |
269 | ||
270 | /** | |
271 | * attribute_container_add_attrs - add attributes | |
272 | * | |
273 | * @classdev: The class device | |
274 | * | |
275 | * This simply creates all the class device sysfs files from the | |
276 | * attributes listed in the container | |
277 | */ | |
278 | int | |
279 | attribute_container_add_attrs(struct class_device *classdev) | |
280 | { | |
281 | struct attribute_container *cont = | |
282 | attribute_container_classdev_to_container(classdev); | |
283 | struct class_device_attribute **attrs = cont->attrs; | |
284 | int i, error; | |
285 | ||
286 | if (!attrs) | |
287 | return 0; | |
288 | ||
289 | for (i = 0; attrs[i]; i++) { | |
290 | error = class_device_create_file(classdev, attrs[i]); | |
291 | if (error) | |
292 | return error; | |
293 | } | |
294 | ||
295 | return 0; | |
296 | } | |
297 | EXPORT_SYMBOL_GPL(attribute_container_add_attrs); | |
298 | ||
299 | /** | |
300 | * attribute_container_add_class_device - same function as class_device_add | |
301 | * | |
302 | * @classdev: the class device to add | |
303 | * | |
304 | * This performs essentially the same function as class_device_add except for | |
305 | * attribute containers, namely add the classdev to the system and then | |
306 | * create the attribute files | |
307 | */ | |
308 | int | |
309 | attribute_container_add_class_device(struct class_device *classdev) | |
310 | { | |
311 | int error = class_device_add(classdev); | |
312 | if (error) | |
313 | return error; | |
314 | return attribute_container_add_attrs(classdev); | |
315 | } | |
316 | EXPORT_SYMBOL_GPL(attribute_container_add_class_device); | |
317 | ||
318 | /** | |
319 | * attribute_container_add_class_device_adapter - simple adapter for triggers | |
320 | * | |
321 | * This function is identical to attribute_container_add_class_device except | |
322 | * that it is designed to be called from the triggers | |
323 | */ | |
324 | int | |
325 | attribute_container_add_class_device_adapter(struct attribute_container *cont, | |
326 | struct device *dev, | |
327 | struct class_device *classdev) | |
328 | { | |
329 | return attribute_container_add_class_device(classdev); | |
330 | } | |
331 | EXPORT_SYMBOL_GPL(attribute_container_add_class_device_adapter); | |
332 | ||
333 | /** | |
334 | * attribute_container_remove_attrs - remove any attribute files | |
335 | * | |
336 | * @classdev: The class device to remove the files from | |
337 | * | |
338 | */ | |
339 | void | |
340 | attribute_container_remove_attrs(struct class_device *classdev) | |
341 | { | |
342 | struct attribute_container *cont = | |
343 | attribute_container_classdev_to_container(classdev); | |
344 | struct class_device_attribute **attrs = cont->attrs; | |
345 | int i; | |
346 | ||
347 | if (!attrs) | |
348 | return; | |
349 | ||
350 | for (i = 0; attrs[i]; i++) | |
351 | class_device_remove_file(classdev, attrs[i]); | |
352 | } | |
353 | EXPORT_SYMBOL_GPL(attribute_container_remove_attrs); | |
354 | ||
355 | /** | |
356 | * attribute_container_class_device_del - equivalent of class_device_del | |
357 | * | |
358 | * @classdev: the class device | |
359 | * | |
360 | * This function simply removes all the attribute files and then calls | |
361 | * class_device_del. | |
362 | */ | |
363 | void | |
364 | attribute_container_class_device_del(struct class_device *classdev) | |
365 | { | |
366 | attribute_container_remove_attrs(classdev); | |
367 | class_device_del(classdev); | |
368 | } | |
369 | EXPORT_SYMBOL_GPL(attribute_container_class_device_del); | |
370 | ||
371 | int __init | |
372 | attribute_container_init(void) | |
373 | { | |
374 | INIT_LIST_HEAD(&attribute_container_list); | |
375 | return 0; | |
376 | } |