Commit | Line | Data |
---|---|---|
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 | ||
21 | struct master { | |
22 | struct list_head node; | |
23 | struct list_head components; | |
24 | bool bound; | |
25 | ||
26 | const struct component_master_ops *ops; | |
27 | struct device *dev; | |
28 | }; | |
29 | ||
30 | struct component { | |
31 | struct list_head node; | |
32 | struct list_head master_node; | |
33 | struct master *master; | |
34 | bool bound; | |
35 | ||
36 | const struct component_ops *ops; | |
37 | struct device *dev; | |
38 | }; | |
39 | ||
40 | static DEFINE_MUTEX(component_mutex); | |
41 | static LIST_HEAD(component_list); | |
42 | static LIST_HEAD(masters); | |
43 | ||
44 | static struct master *__master_find(struct device *dev, | |
45 | const struct component_master_ops *ops) | |
46 | { | |
47 | struct master *m; | |
48 | ||
49 | list_for_each_entry(m, &masters, node) | |
50 | if (m->dev == dev && (!ops || m->ops == ops)) | |
51 | return m; | |
52 | ||
53 | return NULL; | |
54 | } | |
55 | ||
56 | /* Attach an unattached component to a master. */ | |
57 | static void component_attach_master(struct master *master, struct component *c) | |
58 | { | |
59 | c->master = master; | |
60 | ||
61 | list_add_tail(&c->master_node, &master->components); | |
62 | } | |
63 | ||
64 | /* Detach a component from a master. */ | |
65 | static void component_detach_master(struct master *master, struct component *c) | |
66 | { | |
67 | list_del(&c->master_node); | |
68 | ||
69 | c->master = NULL; | |
70 | } | |
71 | ||
72 | int component_master_add_child(struct master *master, | |
73 | int (*compare)(struct device *, void *), void *compare_data) | |
74 | { | |
75 | struct component *c; | |
76 | int ret = -ENXIO; | |
77 | ||
78 | list_for_each_entry(c, &component_list, node) { | |
79 | if (c->master) | |
80 | continue; | |
81 | ||
82 | if (compare(c->dev, compare_data)) { | |
83 | component_attach_master(master, c); | |
84 | ret = 0; | |
85 | break; | |
86 | } | |
87 | } | |
88 | ||
89 | return ret; | |
90 | } | |
91 | EXPORT_SYMBOL_GPL(component_master_add_child); | |
92 | ||
93 | /* Detach all attached components from this master */ | |
94 | static void master_remove_components(struct master *master) | |
95 | { | |
96 | while (!list_empty(&master->components)) { | |
97 | struct component *c = list_first_entry(&master->components, | |
98 | struct component, master_node); | |
99 | ||
100 | WARN_ON(c->master != master); | |
101 | ||
102 | component_detach_master(master, c); | |
103 | } | |
104 | } | |
105 | ||
106 | /* | |
107 | * Try to bring up a master. If component is NULL, we're interested in | |
108 | * this master, otherwise it's a component which must be present to try | |
109 | * and bring up the master. | |
110 | * | |
111 | * Returns 1 for successful bringup, 0 if not ready, or -ve errno. | |
112 | */ | |
113 | static int try_to_bring_up_master(struct master *master, | |
114 | struct component *component) | |
115 | { | |
116 | int ret = 0; | |
117 | ||
118 | if (!master->bound) { | |
119 | /* | |
120 | * Search the list of components, looking for components that | |
121 | * belong to this master, and attach them to the master. | |
122 | */ | |
123 | if (master->ops->add_components(master->dev, master)) { | |
124 | /* Failed to find all components */ | |
125 | master_remove_components(master); | |
126 | ret = 0; | |
127 | goto out; | |
128 | } | |
129 | ||
130 | if (component && component->master != master) { | |
131 | master_remove_components(master); | |
132 | ret = 0; | |
133 | goto out; | |
134 | } | |
135 | ||
136 | /* Found all components */ | |
137 | ret = master->ops->bind(master->dev); | |
138 | if (ret < 0) { | |
139 | master_remove_components(master); | |
140 | goto out; | |
141 | } | |
142 | ||
143 | master->bound = true; | |
144 | ret = 1; | |
145 | } | |
146 | out: | |
147 | ||
148 | return ret; | |
149 | } | |
150 | ||
151 | static int try_to_bring_up_masters(struct component *component) | |
152 | { | |
153 | struct master *m; | |
154 | int ret = 0; | |
155 | ||
156 | list_for_each_entry(m, &masters, node) { | |
157 | ret = try_to_bring_up_master(m, component); | |
158 | if (ret != 0) | |
159 | break; | |
160 | } | |
161 | ||
162 | return ret; | |
163 | } | |
164 | ||
165 | static void take_down_master(struct master *master) | |
166 | { | |
167 | if (master->bound) { | |
168 | master->ops->unbind(master->dev); | |
169 | master->bound = false; | |
170 | } | |
171 | ||
172 | master_remove_components(master); | |
173 | } | |
174 | ||
175 | int component_master_add(struct device *dev, | |
176 | const struct component_master_ops *ops) | |
177 | { | |
178 | struct master *master; | |
179 | int ret; | |
180 | ||
181 | master = kzalloc(sizeof(*master), GFP_KERNEL); | |
182 | if (!master) | |
183 | return -ENOMEM; | |
184 | ||
185 | master->dev = dev; | |
186 | master->ops = ops; | |
187 | INIT_LIST_HEAD(&master->components); | |
188 | ||
189 | /* Add to the list of available masters. */ | |
190 | mutex_lock(&component_mutex); | |
191 | list_add(&master->node, &masters); | |
192 | ||
193 | ret = try_to_bring_up_master(master, NULL); | |
194 | ||
195 | if (ret < 0) { | |
196 | /* Delete off the list if we weren't successful */ | |
197 | list_del(&master->node); | |
198 | kfree(master); | |
199 | } | |
200 | mutex_unlock(&component_mutex); | |
201 | ||
202 | return ret < 0 ? ret : 0; | |
203 | } | |
204 | EXPORT_SYMBOL_GPL(component_master_add); | |
205 | ||
206 | void component_master_del(struct device *dev, | |
207 | const struct component_master_ops *ops) | |
208 | { | |
209 | struct master *master; | |
210 | ||
211 | mutex_lock(&component_mutex); | |
212 | master = __master_find(dev, ops); | |
213 | if (master) { | |
214 | take_down_master(master); | |
215 | ||
216 | list_del(&master->node); | |
217 | kfree(master); | |
218 | } | |
219 | mutex_unlock(&component_mutex); | |
220 | } | |
221 | EXPORT_SYMBOL_GPL(component_master_del); | |
222 | ||
223 | static void component_unbind(struct component *component, | |
224 | struct master *master, void *data) | |
225 | { | |
226 | WARN_ON(!component->bound); | |
227 | ||
228 | component->ops->unbind(component->dev, master->dev, data); | |
229 | component->bound = false; | |
230 | ||
231 | /* Release all resources claimed in the binding of this component */ | |
232 | devres_release_group(component->dev, component); | |
233 | } | |
234 | ||
235 | void component_unbind_all(struct device *master_dev, void *data) | |
236 | { | |
237 | struct master *master; | |
238 | struct component *c; | |
239 | ||
240 | WARN_ON(!mutex_is_locked(&component_mutex)); | |
241 | ||
242 | master = __master_find(master_dev, NULL); | |
243 | if (!master) | |
244 | return; | |
245 | ||
246 | list_for_each_entry_reverse(c, &master->components, master_node) | |
247 | component_unbind(c, master, data); | |
248 | } | |
249 | EXPORT_SYMBOL_GPL(component_unbind_all); | |
250 | ||
251 | static int component_bind(struct component *component, struct master *master, | |
252 | void *data) | |
253 | { | |
254 | int ret; | |
255 | ||
256 | /* | |
257 | * Each component initialises inside its own devres group. | |
258 | * This allows us to roll-back a failed component without | |
259 | * affecting anything else. | |
260 | */ | |
261 | if (!devres_open_group(master->dev, NULL, GFP_KERNEL)) | |
262 | return -ENOMEM; | |
263 | ||
264 | /* | |
265 | * Also open a group for the device itself: this allows us | |
266 | * to release the resources claimed against the sub-device | |
267 | * at the appropriate moment. | |
268 | */ | |
269 | if (!devres_open_group(component->dev, component, GFP_KERNEL)) { | |
270 | devres_release_group(master->dev, NULL); | |
271 | return -ENOMEM; | |
272 | } | |
273 | ||
274 | dev_dbg(master->dev, "binding %s (ops %ps)\n", | |
275 | dev_name(component->dev), component->ops); | |
276 | ||
277 | ret = component->ops->bind(component->dev, master->dev, data); | |
278 | if (!ret) { | |
279 | component->bound = true; | |
280 | ||
281 | /* | |
282 | * Close the component device's group so that resources | |
283 | * allocated in the binding are encapsulated for removal | |
284 | * at unbind. Remove the group on the DRM device as we | |
285 | * can clean those resources up independently. | |
286 | */ | |
287 | devres_close_group(component->dev, NULL); | |
288 | devres_remove_group(master->dev, NULL); | |
289 | ||
290 | dev_info(master->dev, "bound %s (ops %ps)\n", | |
291 | dev_name(component->dev), component->ops); | |
292 | } else { | |
293 | devres_release_group(component->dev, NULL); | |
294 | devres_release_group(master->dev, NULL); | |
295 | ||
296 | dev_err(master->dev, "failed to bind %s (ops %ps): %d\n", | |
297 | dev_name(component->dev), component->ops, ret); | |
298 | } | |
299 | ||
300 | return ret; | |
301 | } | |
302 | ||
303 | int component_bind_all(struct device *master_dev, void *data) | |
304 | { | |
305 | struct master *master; | |
306 | struct component *c; | |
307 | int ret = 0; | |
308 | ||
309 | WARN_ON(!mutex_is_locked(&component_mutex)); | |
310 | ||
311 | master = __master_find(master_dev, NULL); | |
312 | if (!master) | |
313 | return -EINVAL; | |
314 | ||
315 | list_for_each_entry(c, &master->components, master_node) { | |
316 | ret = component_bind(c, master, data); | |
317 | if (ret) | |
318 | break; | |
319 | } | |
320 | ||
321 | if (ret != 0) { | |
322 | list_for_each_entry_continue_reverse(c, &master->components, | |
323 | master_node) | |
324 | component_unbind(c, master, data); | |
325 | } | |
326 | ||
327 | return ret; | |
328 | } | |
329 | EXPORT_SYMBOL_GPL(component_bind_all); | |
330 | ||
331 | int component_add(struct device *dev, const struct component_ops *ops) | |
332 | { | |
333 | struct component *component; | |
334 | int ret; | |
335 | ||
336 | component = kzalloc(sizeof(*component), GFP_KERNEL); | |
337 | if (!component) | |
338 | return -ENOMEM; | |
339 | ||
340 | component->ops = ops; | |
341 | component->dev = dev; | |
342 | ||
343 | dev_dbg(dev, "adding component (ops %ps)\n", ops); | |
344 | ||
345 | mutex_lock(&component_mutex); | |
346 | list_add_tail(&component->node, &component_list); | |
347 | ||
348 | ret = try_to_bring_up_masters(component); | |
349 | if (ret < 0) { | |
350 | list_del(&component->node); | |
351 | ||
352 | kfree(component); | |
353 | } | |
354 | mutex_unlock(&component_mutex); | |
355 | ||
356 | return ret < 0 ? ret : 0; | |
357 | } | |
358 | EXPORT_SYMBOL_GPL(component_add); | |
359 | ||
360 | void component_del(struct device *dev, const struct component_ops *ops) | |
361 | { | |
362 | struct component *c, *component = NULL; | |
363 | ||
364 | mutex_lock(&component_mutex); | |
365 | list_for_each_entry(c, &component_list, node) | |
366 | if (c->dev == dev && c->ops == ops) { | |
367 | list_del(&c->node); | |
368 | component = c; | |
369 | break; | |
370 | } | |
371 | ||
372 | if (component && component->master) | |
373 | take_down_master(component->master); | |
374 | ||
375 | mutex_unlock(&component_mutex); | |
376 | ||
377 | WARN_ON(!component); | |
378 | kfree(component); | |
379 | } | |
380 | EXPORT_SYMBOL_GPL(component_del); | |
381 | ||
382 | MODULE_LICENSE("GPL v2"); |