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1da177e4 LT |
1 | /* |
2 | * drivers/base/core.c - core driver model code (device registration, etc) | |
3 | * | |
4 | * Copyright (c) 2002-3 Patrick Mochel | |
5 | * Copyright (c) 2002-3 Open Source Development Labs | |
6 | * | |
7 | * This file is released under the GPLv2 | |
8 | * | |
9 | */ | |
10 | ||
11 | #include <linux/config.h> | |
12 | #include <linux/device.h> | |
13 | #include <linux/err.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/string.h> | |
18 | ||
19 | #include <asm/semaphore.h> | |
20 | ||
21 | #include "base.h" | |
22 | #include "power/power.h" | |
23 | ||
24 | int (*platform_notify)(struct device * dev) = NULL; | |
25 | int (*platform_notify_remove)(struct device * dev) = NULL; | |
26 | ||
27 | /* | |
28 | * sysfs bindings for devices. | |
29 | */ | |
30 | ||
31 | #define to_dev(obj) container_of(obj, struct device, kobj) | |
32 | #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr) | |
33 | ||
34 | extern struct attribute * dev_default_attrs[]; | |
35 | ||
36 | static ssize_t | |
37 | dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf) | |
38 | { | |
39 | struct device_attribute * dev_attr = to_dev_attr(attr); | |
40 | struct device * dev = to_dev(kobj); | |
41 | ssize_t ret = 0; | |
42 | ||
43 | if (dev_attr->show) | |
44 | ret = dev_attr->show(dev, buf); | |
45 | return ret; | |
46 | } | |
47 | ||
48 | static ssize_t | |
49 | dev_attr_store(struct kobject * kobj, struct attribute * attr, | |
50 | const char * buf, size_t count) | |
51 | { | |
52 | struct device_attribute * dev_attr = to_dev_attr(attr); | |
53 | struct device * dev = to_dev(kobj); | |
54 | ssize_t ret = 0; | |
55 | ||
56 | if (dev_attr->store) | |
57 | ret = dev_attr->store(dev, buf, count); | |
58 | return ret; | |
59 | } | |
60 | ||
61 | static struct sysfs_ops dev_sysfs_ops = { | |
62 | .show = dev_attr_show, | |
63 | .store = dev_attr_store, | |
64 | }; | |
65 | ||
66 | ||
67 | /** | |
68 | * device_release - free device structure. | |
69 | * @kobj: device's kobject. | |
70 | * | |
71 | * This is called once the reference count for the object | |
72 | * reaches 0. We forward the call to the device's release | |
73 | * method, which should handle actually freeing the structure. | |
74 | */ | |
75 | static void device_release(struct kobject * kobj) | |
76 | { | |
77 | struct device * dev = to_dev(kobj); | |
78 | ||
79 | if (dev->release) | |
80 | dev->release(dev); | |
81 | else { | |
82 | printk(KERN_ERR "Device '%s' does not have a release() function, " | |
83 | "it is broken and must be fixed.\n", | |
84 | dev->bus_id); | |
85 | WARN_ON(1); | |
86 | } | |
87 | } | |
88 | ||
89 | static struct kobj_type ktype_device = { | |
90 | .release = device_release, | |
91 | .sysfs_ops = &dev_sysfs_ops, | |
92 | .default_attrs = dev_default_attrs, | |
93 | }; | |
94 | ||
95 | ||
96 | static int dev_hotplug_filter(struct kset *kset, struct kobject *kobj) | |
97 | { | |
98 | struct kobj_type *ktype = get_ktype(kobj); | |
99 | ||
100 | if (ktype == &ktype_device) { | |
101 | struct device *dev = to_dev(kobj); | |
102 | if (dev->bus) | |
103 | return 1; | |
104 | } | |
105 | return 0; | |
106 | } | |
107 | ||
108 | static char *dev_hotplug_name(struct kset *kset, struct kobject *kobj) | |
109 | { | |
110 | struct device *dev = to_dev(kobj); | |
111 | ||
112 | return dev->bus->name; | |
113 | } | |
114 | ||
115 | static int dev_hotplug(struct kset *kset, struct kobject *kobj, char **envp, | |
116 | int num_envp, char *buffer, int buffer_size) | |
117 | { | |
118 | struct device *dev = to_dev(kobj); | |
119 | int i = 0; | |
120 | int length = 0; | |
121 | int retval = 0; | |
122 | ||
123 | /* add bus name of physical device */ | |
124 | if (dev->bus) | |
125 | add_hotplug_env_var(envp, num_envp, &i, | |
126 | buffer, buffer_size, &length, | |
127 | "PHYSDEVBUS=%s", dev->bus->name); | |
128 | ||
129 | /* add driver name of physical device */ | |
130 | if (dev->driver) | |
131 | add_hotplug_env_var(envp, num_envp, &i, | |
132 | buffer, buffer_size, &length, | |
133 | "PHYSDEVDRIVER=%s", dev->driver->name); | |
134 | ||
135 | /* terminate, set to next free slot, shrink available space */ | |
136 | envp[i] = NULL; | |
137 | envp = &envp[i]; | |
138 | num_envp -= i; | |
139 | buffer = &buffer[length]; | |
140 | buffer_size -= length; | |
141 | ||
142 | if (dev->bus->hotplug) { | |
143 | /* have the bus specific function add its stuff */ | |
144 | retval = dev->bus->hotplug (dev, envp, num_envp, buffer, buffer_size); | |
145 | if (retval) { | |
146 | pr_debug ("%s - hotplug() returned %d\n", | |
147 | __FUNCTION__, retval); | |
148 | } | |
149 | } | |
150 | ||
151 | return retval; | |
152 | } | |
153 | ||
154 | static struct kset_hotplug_ops device_hotplug_ops = { | |
155 | .filter = dev_hotplug_filter, | |
156 | .name = dev_hotplug_name, | |
157 | .hotplug = dev_hotplug, | |
158 | }; | |
159 | ||
160 | /** | |
161 | * device_subsys - structure to be registered with kobject core. | |
162 | */ | |
163 | ||
164 | decl_subsys(devices, &ktype_device, &device_hotplug_ops); | |
165 | ||
166 | ||
167 | /** | |
168 | * device_create_file - create sysfs attribute file for device. | |
169 | * @dev: device. | |
170 | * @attr: device attribute descriptor. | |
171 | */ | |
172 | ||
173 | int device_create_file(struct device * dev, struct device_attribute * attr) | |
174 | { | |
175 | int error = 0; | |
176 | if (get_device(dev)) { | |
177 | error = sysfs_create_file(&dev->kobj, &attr->attr); | |
178 | put_device(dev); | |
179 | } | |
180 | return error; | |
181 | } | |
182 | ||
183 | /** | |
184 | * device_remove_file - remove sysfs attribute file. | |
185 | * @dev: device. | |
186 | * @attr: device attribute descriptor. | |
187 | */ | |
188 | ||
189 | void device_remove_file(struct device * dev, struct device_attribute * attr) | |
190 | { | |
191 | if (get_device(dev)) { | |
192 | sysfs_remove_file(&dev->kobj, &attr->attr); | |
193 | put_device(dev); | |
194 | } | |
195 | } | |
196 | ||
197 | ||
198 | /** | |
199 | * device_initialize - init device structure. | |
200 | * @dev: device. | |
201 | * | |
202 | * This prepares the device for use by other layers, | |
203 | * including adding it to the device hierarchy. | |
204 | * It is the first half of device_register(), if called by | |
205 | * that, though it can also be called separately, so one | |
206 | * may use @dev's fields (e.g. the refcount). | |
207 | */ | |
208 | ||
209 | void device_initialize(struct device *dev) | |
210 | { | |
211 | kobj_set_kset_s(dev, devices_subsys); | |
212 | kobject_init(&dev->kobj); | |
213 | INIT_LIST_HEAD(&dev->node); | |
214 | INIT_LIST_HEAD(&dev->children); | |
215 | INIT_LIST_HEAD(&dev->driver_list); | |
216 | INIT_LIST_HEAD(&dev->bus_list); | |
217 | INIT_LIST_HEAD(&dev->dma_pools); | |
218 | } | |
219 | ||
220 | /** | |
221 | * device_add - add device to device hierarchy. | |
222 | * @dev: device. | |
223 | * | |
224 | * This is part 2 of device_register(), though may be called | |
225 | * separately _iff_ device_initialize() has been called separately. | |
226 | * | |
227 | * This adds it to the kobject hierarchy via kobject_add(), adds it | |
228 | * to the global and sibling lists for the device, then | |
229 | * adds it to the other relevant subsystems of the driver model. | |
230 | */ | |
231 | int device_add(struct device *dev) | |
232 | { | |
233 | struct device *parent = NULL; | |
234 | int error = -EINVAL; | |
235 | ||
236 | dev = get_device(dev); | |
237 | if (!dev || !strlen(dev->bus_id)) | |
238 | goto Error; | |
239 | ||
240 | parent = get_device(dev->parent); | |
241 | ||
242 | pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id); | |
243 | ||
244 | /* first, register with generic layer. */ | |
245 | kobject_set_name(&dev->kobj, "%s", dev->bus_id); | |
246 | if (parent) | |
247 | dev->kobj.parent = &parent->kobj; | |
248 | ||
249 | if ((error = kobject_add(&dev->kobj))) | |
250 | goto Error; | |
251 | if ((error = device_pm_add(dev))) | |
252 | goto PMError; | |
253 | if ((error = bus_add_device(dev))) | |
254 | goto BusError; | |
255 | down_write(&devices_subsys.rwsem); | |
256 | if (parent) | |
257 | list_add_tail(&dev->node, &parent->children); | |
258 | up_write(&devices_subsys.rwsem); | |
259 | ||
260 | /* notify platform of device entry */ | |
261 | if (platform_notify) | |
262 | platform_notify(dev); | |
263 | Done: | |
264 | put_device(dev); | |
265 | return error; | |
266 | BusError: | |
267 | device_pm_remove(dev); | |
268 | PMError: | |
269 | kobject_del(&dev->kobj); | |
270 | Error: | |
271 | if (parent) | |
272 | put_device(parent); | |
273 | goto Done; | |
274 | } | |
275 | ||
276 | ||
277 | /** | |
278 | * device_register - register a device with the system. | |
279 | * @dev: pointer to the device structure | |
280 | * | |
281 | * This happens in two clean steps - initialize the device | |
282 | * and add it to the system. The two steps can be called | |
283 | * separately, but this is the easiest and most common. | |
284 | * I.e. you should only call the two helpers separately if | |
285 | * have a clearly defined need to use and refcount the device | |
286 | * before it is added to the hierarchy. | |
287 | */ | |
288 | ||
289 | int device_register(struct device *dev) | |
290 | { | |
291 | device_initialize(dev); | |
292 | return device_add(dev); | |
293 | } | |
294 | ||
295 | ||
296 | /** | |
297 | * get_device - increment reference count for device. | |
298 | * @dev: device. | |
299 | * | |
300 | * This simply forwards the call to kobject_get(), though | |
301 | * we do take care to provide for the case that we get a NULL | |
302 | * pointer passed in. | |
303 | */ | |
304 | ||
305 | struct device * get_device(struct device * dev) | |
306 | { | |
307 | return dev ? to_dev(kobject_get(&dev->kobj)) : NULL; | |
308 | } | |
309 | ||
310 | ||
311 | /** | |
312 | * put_device - decrement reference count. | |
313 | * @dev: device in question. | |
314 | */ | |
315 | void put_device(struct device * dev) | |
316 | { | |
317 | if (dev) | |
318 | kobject_put(&dev->kobj); | |
319 | } | |
320 | ||
321 | ||
322 | /** | |
323 | * device_del - delete device from system. | |
324 | * @dev: device. | |
325 | * | |
326 | * This is the first part of the device unregistration | |
327 | * sequence. This removes the device from the lists we control | |
328 | * from here, has it removed from the other driver model | |
329 | * subsystems it was added to in device_add(), and removes it | |
330 | * from the kobject hierarchy. | |
331 | * | |
332 | * NOTE: this should be called manually _iff_ device_add() was | |
333 | * also called manually. | |
334 | */ | |
335 | ||
336 | void device_del(struct device * dev) | |
337 | { | |
338 | struct device * parent = dev->parent; | |
339 | ||
340 | down_write(&devices_subsys.rwsem); | |
341 | if (parent) | |
342 | list_del_init(&dev->node); | |
343 | up_write(&devices_subsys.rwsem); | |
344 | ||
345 | /* Notify the platform of the removal, in case they | |
346 | * need to do anything... | |
347 | */ | |
348 | if (platform_notify_remove) | |
349 | platform_notify_remove(dev); | |
350 | bus_remove_device(dev); | |
351 | device_pm_remove(dev); | |
352 | kobject_del(&dev->kobj); | |
353 | if (parent) | |
354 | put_device(parent); | |
355 | } | |
356 | ||
357 | /** | |
358 | * device_unregister - unregister device from system. | |
359 | * @dev: device going away. | |
360 | * | |
361 | * We do this in two parts, like we do device_register(). First, | |
362 | * we remove it from all the subsystems with device_del(), then | |
363 | * we decrement the reference count via put_device(). If that | |
364 | * is the final reference count, the device will be cleaned up | |
365 | * via device_release() above. Otherwise, the structure will | |
366 | * stick around until the final reference to the device is dropped. | |
367 | */ | |
368 | void device_unregister(struct device * dev) | |
369 | { | |
370 | pr_debug("DEV: Unregistering device. ID = '%s'\n", dev->bus_id); | |
371 | device_del(dev); | |
372 | put_device(dev); | |
373 | } | |
374 | ||
375 | ||
376 | /** | |
377 | * device_for_each_child - device child iterator. | |
378 | * @dev: parent struct device. | |
379 | * @data: data for the callback. | |
380 | * @fn: function to be called for each device. | |
381 | * | |
382 | * Iterate over @dev's child devices, and call @fn for each, | |
383 | * passing it @data. | |
384 | * | |
385 | * We check the return of @fn each time. If it returns anything | |
386 | * other than 0, we break out and return that value. | |
387 | */ | |
388 | int device_for_each_child(struct device * dev, void * data, | |
389 | int (*fn)(struct device *, void *)) | |
390 | { | |
391 | struct device * child; | |
392 | int error = 0; | |
393 | ||
394 | down_read(&devices_subsys.rwsem); | |
395 | list_for_each_entry(child, &dev->children, node) { | |
396 | if((error = fn(child, data))) | |
397 | break; | |
398 | } | |
399 | up_read(&devices_subsys.rwsem); | |
400 | return error; | |
401 | } | |
402 | ||
403 | /** | |
404 | * device_find - locate device on a bus by name. | |
405 | * @name: name of the device. | |
406 | * @bus: bus to scan for the device. | |
407 | * | |
408 | * Call kset_find_obj() to iterate over list of devices on | |
409 | * a bus to find device by name. Return device if found. | |
410 | * | |
411 | * Note that kset_find_obj increments device's reference count. | |
412 | */ | |
413 | struct device *device_find(const char *name, struct bus_type *bus) | |
414 | { | |
415 | struct kobject *k = kset_find_obj(&bus->devices, name); | |
416 | if (k) | |
417 | return to_dev(k); | |
418 | return NULL; | |
419 | } | |
420 | ||
421 | int __init devices_init(void) | |
422 | { | |
423 | return subsystem_register(&devices_subsys); | |
424 | } | |
425 | ||
426 | EXPORT_SYMBOL_GPL(device_for_each_child); | |
427 | ||
428 | EXPORT_SYMBOL_GPL(device_initialize); | |
429 | EXPORT_SYMBOL_GPL(device_add); | |
430 | EXPORT_SYMBOL_GPL(device_register); | |
431 | ||
432 | EXPORT_SYMBOL_GPL(device_del); | |
433 | EXPORT_SYMBOL_GPL(device_unregister); | |
434 | EXPORT_SYMBOL_GPL(get_device); | |
435 | EXPORT_SYMBOL_GPL(put_device); | |
436 | EXPORT_SYMBOL_GPL(device_find); | |
437 | ||
438 | EXPORT_SYMBOL_GPL(device_create_file); | |
439 | EXPORT_SYMBOL_GPL(device_remove_file); |