1 /*
2 * sys.c - pseudo-bus for system 'devices' (cpus, PICs, timers, etc)
3 *
4 * Copyright (c) 2002-3 Patrick Mochel
5 * 2002-3 Open Source Development Lab
6 *
7 * This file is released under the GPLv2
8 *
9 * This exports a 'system' bus type.
10 * By default, a 'sys' bus gets added to the root of the system. There will
11 * always be core system devices. Devices can use sysdev_register() to
12 * add themselves as children of the system bus.
13 */
14
15 #include <linux/config.h>
16 #include <linux/sysdev.h>
17 #include <linux/err.h>
18 #include <linux/module.h>
19 #include <linux/kernel.h>
20 #include <linux/init.h>
21 #include <linux/slab.h>
22 #include <linux/string.h>
23
24
25 extern struct subsystem devices_subsys;
26
27 #define to_sysdev(k) container_of(k, struct sys_device, kobj)
28 #define to_sysdev_attr(a) container_of(a, struct sysdev_attribute, attr)
29
30
31 static ssize_t
32 sysdev_show(struct kobject * kobj, struct attribute * attr, char * buffer)
33 {
34 struct sys_device * sysdev = to_sysdev(kobj);
35 struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);
36
37 if (sysdev_attr->show)
38 return sysdev_attr->show(sysdev, buffer);
39 return 0;
40 }
41
42
43 static ssize_t
44 sysdev_store(struct kobject * kobj, struct attribute * attr,
45 const char * buffer, size_t count)
46 {
47 struct sys_device * sysdev = to_sysdev(kobj);
48 struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);
49
50 if (sysdev_attr->store)
51 return sysdev_attr->store(sysdev, buffer, count);
52 return 0;
53 }
54
55 static struct sysfs_ops sysfs_ops = {
56 .show = sysdev_show,
57 .store = sysdev_store,
58 };
59
60 static struct kobj_type ktype_sysdev = {
61 .sysfs_ops = &sysfs_ops,
62 };
63
64
65 int sysdev_create_file(struct sys_device * s, struct sysdev_attribute * a)
66 {
67 return sysfs_create_file(&s->kobj, &a->attr);
68 }
69
70
71 void sysdev_remove_file(struct sys_device * s, struct sysdev_attribute * a)
72 {
73 sysfs_remove_file(&s->kobj, &a->attr);
74 }
75
76 EXPORT_SYMBOL_GPL(sysdev_create_file);
77 EXPORT_SYMBOL_GPL(sysdev_remove_file);
78
79 /*
80 * declare system_subsys
81 */
82 decl_subsys(system, &ktype_sysdev, NULL);
83
84 int sysdev_class_register(struct sysdev_class * cls)
85 {
86 pr_debug("Registering sysdev class '%s'\n",
87 kobject_name(&cls->kset.kobj));
88 INIT_LIST_HEAD(&cls->drivers);
89 cls->kset.subsys = &system_subsys;
90 kset_set_kset_s(cls, system_subsys);
91 return kset_register(&cls->kset);
92 }
93
94 void sysdev_class_unregister(struct sysdev_class * cls)
95 {
96 pr_debug("Unregistering sysdev class '%s'\n",
97 kobject_name(&cls->kset.kobj));
98 kset_unregister(&cls->kset);
99 }
100
101 EXPORT_SYMBOL_GPL(sysdev_class_register);
102 EXPORT_SYMBOL_GPL(sysdev_class_unregister);
103
104
105 static LIST_HEAD(global_drivers);
106
107 /**
108 * sysdev_driver_register - Register auxillary driver
109 * @cls: Device class driver belongs to.
110 * @drv: Driver.
111 *
112 * If @cls is valid, then @drv is inserted into @cls->drivers to be
113 * called on each operation on devices of that class. The refcount
114 * of @cls is incremented.
115 * Otherwise, @drv is inserted into global_drivers, and called for
116 * each device.
117 */
118
119 int sysdev_driver_register(struct sysdev_class * cls,
120 struct sysdev_driver * drv)
121 {
122 down_write(&system_subsys.rwsem);
123 if (cls && kset_get(&cls->kset)) {
124 list_add_tail(&drv->entry, &cls->drivers);
125
126 /* If devices of this class already exist, tell the driver */
127 if (drv->add) {
128 struct sys_device *dev;
129 list_for_each_entry(dev, &cls->kset.list, kobj.entry)
130 drv->add(dev);
131 }
132 } else
133 list_add_tail(&drv->entry, &global_drivers);
134 up_write(&system_subsys.rwsem);
135 return 0;
136 }
137
138
139 /**
140 * sysdev_driver_unregister - Remove an auxillary driver.
141 * @cls: Class driver belongs to.
142 * @drv: Driver.
143 */
144 void sysdev_driver_unregister(struct sysdev_class * cls,
145 struct sysdev_driver * drv)
146 {
147 down_write(&system_subsys.rwsem);
148 list_del_init(&drv->entry);
149 if (cls) {
150 if (drv->remove) {
151 struct sys_device *dev;
152 list_for_each_entry(dev, &cls->kset.list, kobj.entry)
153 drv->remove(dev);
154 }
155 kset_put(&cls->kset);
156 }
157 up_write(&system_subsys.rwsem);
158 }
159
160 EXPORT_SYMBOL_GPL(sysdev_driver_register);
161 EXPORT_SYMBOL_GPL(sysdev_driver_unregister);
162
163
164
165 /**
166 * sysdev_register - add a system device to the tree
167 * @sysdev: device in question
168 *
169 */
170 int sysdev_register(struct sys_device * sysdev)
171 {
172 int error;
173 struct sysdev_class * cls = sysdev->cls;
174
175 if (!cls)
176 return -EINVAL;
177
178 /* Make sure the kset is set */
179 sysdev->kobj.kset = &cls->kset;
180
181 /* But make sure we point to the right type for sysfs translation */
182 sysdev->kobj.ktype = &ktype_sysdev;
183 error = kobject_set_name(&sysdev->kobj, "%s%d",
184 kobject_name(&cls->kset.kobj), sysdev->id);
185 if (error)
186 return error;
187
188 pr_debug("Registering sys device '%s'\n", kobject_name(&sysdev->kobj));
189
190 /* Register the object */
191 error = kobject_register(&sysdev->kobj);
192
193 if (!error) {
194 struct sysdev_driver * drv;
195
196 down_write(&system_subsys.rwsem);
197 /* Generic notification is implicit, because it's that
198 * code that should have called us.
199 */
200
201 /* Notify global drivers */
202 list_for_each_entry(drv, &global_drivers, entry) {
203 if (drv->add)
204 drv->add(sysdev);
205 }
206
207 /* Notify class auxillary drivers */
208 list_for_each_entry(drv, &cls->drivers, entry) {
209 if (drv->add)
210 drv->add(sysdev);
211 }
212 up_write(&system_subsys.rwsem);
213 }
214 return error;
215 }
216
217 void sysdev_unregister(struct sys_device * sysdev)
218 {
219 struct sysdev_driver * drv;
220
221 down_write(&system_subsys.rwsem);
222 list_for_each_entry(drv, &global_drivers, entry) {
223 if (drv->remove)
224 drv->remove(sysdev);
225 }
226
227 list_for_each_entry(drv, &sysdev->cls->drivers, entry) {
228 if (drv->remove)
229 drv->remove(sysdev);
230 }
231 up_write(&system_subsys.rwsem);
232
233 kobject_unregister(&sysdev->kobj);
234 }
235
236
237
238 /**
239 * sysdev_shutdown - Shut down all system devices.
240 *
241 * Loop over each class of system devices, and the devices in each
242 * of those classes. For each device, we call the shutdown method for
243 * each driver registered for the device - the globals, the auxillaries,
244 * and the class driver.
245 *
246 * Note: The list is iterated in reverse order, so that we shut down
247 * child devices before we shut down thier parents. The list ordering
248 * is guaranteed by virtue of the fact that child devices are registered
249 * after their parents.
250 */
251
252 void sysdev_shutdown(void)
253 {
254 struct sysdev_class * cls;
255
256 pr_debug("Shutting Down System Devices\n");
257
258 down_write(&system_subsys.rwsem);
259 list_for_each_entry_reverse(cls, &system_subsys.kset.list,
260 kset.kobj.entry) {
261 struct sys_device * sysdev;
262
263 pr_debug("Shutting down type '%s':\n",
264 kobject_name(&cls->kset.kobj));
265
266 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
267 struct sysdev_driver * drv;
268 pr_debug(" %s\n", kobject_name(&sysdev->kobj));
269
270 /* Call global drivers first. */
271 list_for_each_entry(drv, &global_drivers, entry) {
272 if (drv->shutdown)
273 drv->shutdown(sysdev);
274 }
275
276 /* Call auxillary drivers next. */
277 list_for_each_entry(drv, &cls->drivers, entry) {
278 if (drv->shutdown)
279 drv->shutdown(sysdev);
280 }
281
282 /* Now call the generic one */
283 if (cls->shutdown)
284 cls->shutdown(sysdev);
285 }
286 }
287 up_write(&system_subsys.rwsem);
288 }
289
290
291 /**
292 * sysdev_suspend - Suspend all system devices.
293 * @state: Power state to enter.
294 *
295 * We perform an almost identical operation as sys_device_shutdown()
296 * above, though calling ->suspend() instead. Interrupts are disabled
297 * when this called. Devices are responsible for both saving state and
298 * quiescing or powering down the device.
299 *
300 * This is only called by the device PM core, so we let them handle
301 * all synchronization.
302 */
303
304 int sysdev_suspend(u32 state)
305 {
306 struct sysdev_class * cls;
307
308 pr_debug("Suspending System Devices\n");
309
310 list_for_each_entry_reverse(cls, &system_subsys.kset.list,
311 kset.kobj.entry) {
312 struct sys_device * sysdev;
313
314 pr_debug("Suspending type '%s':\n",
315 kobject_name(&cls->kset.kobj));
316
317 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
318 struct sysdev_driver * drv;
319 pr_debug(" %s\n", kobject_name(&sysdev->kobj));
320
321 /* Call global drivers first. */
322 list_for_each_entry(drv, &global_drivers, entry) {
323 if (drv->suspend)
324 drv->suspend(sysdev, state);
325 }
326
327 /* Call auxillary drivers next. */
328 list_for_each_entry(drv, &cls->drivers, entry) {
329 if (drv->suspend)
330 drv->suspend(sysdev, state);
331 }
332
333 /* Now call the generic one */
334 if (cls->suspend)
335 cls->suspend(sysdev, state);
336 }
337 }
338 return 0;
339 }
340
341
342 /**
343 * sysdev_resume - Bring system devices back to life.
344 *
345 * Similar to sys_device_suspend(), but we iterate the list forwards
346 * to guarantee that parent devices are resumed before their children.
347 *
348 * Note: Interrupts are disabled when called.
349 */
350
351 int sysdev_resume(void)
352 {
353 struct sysdev_class * cls;
354
355 pr_debug("Resuming System Devices\n");
356
357 list_for_each_entry(cls, &system_subsys.kset.list, kset.kobj.entry) {
358 struct sys_device * sysdev;
359
360 pr_debug("Resuming type '%s':\n",
361 kobject_name(&cls->kset.kobj));
362
363 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
364 struct sysdev_driver * drv;
365 pr_debug(" %s\n", kobject_name(&sysdev->kobj));
366
367 /* First, call the class-specific one */
368 if (cls->resume)
369 cls->resume(sysdev);
370
371 /* Call auxillary drivers next. */
372 list_for_each_entry(drv, &cls->drivers, entry) {
373 if (drv->resume)
374 drv->resume(sysdev);
375 }
376
377 /* Call global drivers. */
378 list_for_each_entry(drv, &global_drivers, entry) {
379 if (drv->resume)
380 drv->resume(sysdev);
381 }
382
383 }
384 }
385 return 0;
386 }
387
388
389 int __init system_bus_init(void)
390 {
391 system_subsys.kset.kobj.parent = &devices_subsys.kset.kobj;
392 return subsystem_register(&system_subsys);
393 }
394
395 EXPORT_SYMBOL_GPL(sysdev_register);
396 EXPORT_SYMBOL_GPL(sysdev_unregister);
397
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