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1da177e4 LT |
1 | /* |
2 | * bus.c - bus driver management | |
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/module.h> | |
14 | #include <linux/errno.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/string.h> | |
17 | #include "base.h" | |
18 | #include "power/power.h" | |
19 | ||
1da177e4 LT |
20 | #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr) |
21 | #define to_bus(obj) container_of(obj, struct bus_type, subsys.kset.kobj) | |
22 | ||
23 | /* | |
24 | * sysfs bindings for drivers | |
25 | */ | |
26 | ||
27 | #define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr) | |
28 | #define to_driver(obj) container_of(obj, struct device_driver, kobj) | |
29 | ||
30 | ||
31 | static ssize_t | |
32 | drv_attr_show(struct kobject * kobj, struct attribute * attr, char * buf) | |
33 | { | |
34 | struct driver_attribute * drv_attr = to_drv_attr(attr); | |
35 | struct device_driver * drv = to_driver(kobj); | |
4a0c20bf | 36 | ssize_t ret = -EIO; |
1da177e4 LT |
37 | |
38 | if (drv_attr->show) | |
39 | ret = drv_attr->show(drv, buf); | |
40 | return ret; | |
41 | } | |
42 | ||
43 | static ssize_t | |
44 | drv_attr_store(struct kobject * kobj, struct attribute * attr, | |
45 | const char * buf, size_t count) | |
46 | { | |
47 | struct driver_attribute * drv_attr = to_drv_attr(attr); | |
48 | struct device_driver * drv = to_driver(kobj); | |
4a0c20bf | 49 | ssize_t ret = -EIO; |
1da177e4 LT |
50 | |
51 | if (drv_attr->store) | |
52 | ret = drv_attr->store(drv, buf, count); | |
53 | return ret; | |
54 | } | |
55 | ||
56 | static struct sysfs_ops driver_sysfs_ops = { | |
57 | .show = drv_attr_show, | |
58 | .store = drv_attr_store, | |
59 | }; | |
60 | ||
61 | ||
62 | static void driver_release(struct kobject * kobj) | |
63 | { | |
64 | struct device_driver * drv = to_driver(kobj); | |
65 | complete(&drv->unloaded); | |
66 | } | |
67 | ||
68 | static struct kobj_type ktype_driver = { | |
69 | .sysfs_ops = &driver_sysfs_ops, | |
70 | .release = driver_release, | |
71 | }; | |
72 | ||
73 | ||
74 | /* | |
75 | * sysfs bindings for buses | |
76 | */ | |
77 | ||
78 | ||
79 | static ssize_t | |
80 | bus_attr_show(struct kobject * kobj, struct attribute * attr, char * buf) | |
81 | { | |
82 | struct bus_attribute * bus_attr = to_bus_attr(attr); | |
83 | struct bus_type * bus = to_bus(kobj); | |
84 | ssize_t ret = 0; | |
85 | ||
86 | if (bus_attr->show) | |
87 | ret = bus_attr->show(bus, buf); | |
88 | return ret; | |
89 | } | |
90 | ||
91 | static ssize_t | |
92 | bus_attr_store(struct kobject * kobj, struct attribute * attr, | |
93 | const char * buf, size_t count) | |
94 | { | |
95 | struct bus_attribute * bus_attr = to_bus_attr(attr); | |
96 | struct bus_type * bus = to_bus(kobj); | |
97 | ssize_t ret = 0; | |
98 | ||
99 | if (bus_attr->store) | |
100 | ret = bus_attr->store(bus, buf, count); | |
101 | return ret; | |
102 | } | |
103 | ||
104 | static struct sysfs_ops bus_sysfs_ops = { | |
105 | .show = bus_attr_show, | |
106 | .store = bus_attr_store, | |
107 | }; | |
108 | ||
109 | int bus_create_file(struct bus_type * bus, struct bus_attribute * attr) | |
110 | { | |
111 | int error; | |
112 | if (get_bus(bus)) { | |
113 | error = sysfs_create_file(&bus->subsys.kset.kobj, &attr->attr); | |
114 | put_bus(bus); | |
115 | } else | |
116 | error = -EINVAL; | |
117 | return error; | |
118 | } | |
119 | ||
120 | void bus_remove_file(struct bus_type * bus, struct bus_attribute * attr) | |
121 | { | |
122 | if (get_bus(bus)) { | |
123 | sysfs_remove_file(&bus->subsys.kset.kobj, &attr->attr); | |
124 | put_bus(bus); | |
125 | } | |
126 | } | |
127 | ||
128 | static struct kobj_type ktype_bus = { | |
129 | .sysfs_ops = &bus_sysfs_ops, | |
130 | ||
131 | }; | |
132 | ||
133 | decl_subsys(bus, &ktype_bus, NULL); | |
134 | ||
1da177e4 | 135 | |
465c7a3a | 136 | static struct device * next_device(struct klist_iter * i) |
137 | { | |
138 | struct klist_node * n = klist_next(i); | |
139 | return n ? container_of(n, struct device, knode_bus) : NULL; | |
140 | } | |
141 | ||
1da177e4 LT |
142 | /** |
143 | * bus_for_each_dev - device iterator. | |
144 | * @bus: bus type. | |
145 | * @start: device to start iterating from. | |
146 | * @data: data for the callback. | |
147 | * @fn: function to be called for each device. | |
148 | * | |
149 | * Iterate over @bus's list of devices, and call @fn for each, | |
150 | * passing it @data. If @start is not NULL, we use that device to | |
151 | * begin iterating from. | |
152 | * | |
153 | * We check the return of @fn each time. If it returns anything | |
154 | * other than 0, we break out and return that value. | |
155 | * | |
156 | * NOTE: The device that returns a non-zero value is not retained | |
157 | * in any way, nor is its refcount incremented. If the caller needs | |
158 | * to retain this data, it should do, and increment the reference | |
159 | * count in the supplied callback. | |
160 | */ | |
161 | ||
162 | int bus_for_each_dev(struct bus_type * bus, struct device * start, | |
163 | void * data, int (*fn)(struct device *, void *)) | |
164 | { | |
465c7a3a | 165 | struct klist_iter i; |
166 | struct device * dev; | |
167 | int error = 0; | |
1da177e4 | 168 | |
465c7a3a | 169 | if (!bus) |
170 | return -EINVAL; | |
171 | ||
172 | klist_iter_init_node(&bus->klist_devices, &i, | |
173 | (start ? &start->knode_bus : NULL)); | |
174 | while ((dev = next_device(&i)) && !error) | |
175 | error = fn(dev, data); | |
176 | klist_iter_exit(&i); | |
177 | return error; | |
1da177e4 LT |
178 | } |
179 | ||
38fdac3c | 180 | |
181 | ||
182 | static struct device_driver * next_driver(struct klist_iter * i) | |
183 | { | |
184 | struct klist_node * n = klist_next(i); | |
185 | return n ? container_of(n, struct device_driver, knode_bus) : NULL; | |
186 | } | |
187 | ||
1da177e4 LT |
188 | /** |
189 | * bus_for_each_drv - driver iterator | |
190 | * @bus: bus we're dealing with. | |
191 | * @start: driver to start iterating on. | |
192 | * @data: data to pass to the callback. | |
193 | * @fn: function to call for each driver. | |
194 | * | |
195 | * This is nearly identical to the device iterator above. | |
196 | * We iterate over each driver that belongs to @bus, and call | |
197 | * @fn for each. If @fn returns anything but 0, we break out | |
198 | * and return it. If @start is not NULL, we use it as the head | |
199 | * of the list. | |
200 | * | |
201 | * NOTE: we don't return the driver that returns a non-zero | |
202 | * value, nor do we leave the reference count incremented for that | |
203 | * driver. If the caller needs to know that info, it must set it | |
204 | * in the callback. It must also be sure to increment the refcount | |
205 | * so it doesn't disappear before returning to the caller. | |
206 | */ | |
207 | ||
208 | int bus_for_each_drv(struct bus_type * bus, struct device_driver * start, | |
209 | void * data, int (*fn)(struct device_driver *, void *)) | |
210 | { | |
38fdac3c | 211 | struct klist_iter i; |
212 | struct device_driver * drv; | |
213 | int error = 0; | |
1da177e4 | 214 | |
38fdac3c | 215 | if (!bus) |
216 | return -EINVAL; | |
217 | ||
218 | klist_iter_init_node(&bus->klist_drivers, &i, | |
219 | start ? &start->knode_bus : NULL); | |
220 | while ((drv = next_driver(&i)) && !error) | |
221 | error = fn(drv, data); | |
222 | klist_iter_exit(&i); | |
223 | return error; | |
1da177e4 LT |
224 | } |
225 | ||
1da177e4 LT |
226 | static int device_add_attrs(struct bus_type * bus, struct device * dev) |
227 | { | |
228 | int error = 0; | |
229 | int i; | |
230 | ||
231 | if (bus->dev_attrs) { | |
232 | for (i = 0; attr_name(bus->dev_attrs[i]); i++) { | |
233 | error = device_create_file(dev,&bus->dev_attrs[i]); | |
234 | if (error) | |
235 | goto Err; | |
236 | } | |
237 | } | |
238 | Done: | |
239 | return error; | |
240 | Err: | |
241 | while (--i >= 0) | |
242 | device_remove_file(dev,&bus->dev_attrs[i]); | |
243 | goto Done; | |
244 | } | |
245 | ||
246 | ||
247 | static void device_remove_attrs(struct bus_type * bus, struct device * dev) | |
248 | { | |
249 | int i; | |
250 | ||
251 | if (bus->dev_attrs) { | |
252 | for (i = 0; attr_name(bus->dev_attrs[i]); i++) | |
253 | device_remove_file(dev,&bus->dev_attrs[i]); | |
254 | } | |
255 | } | |
256 | ||
257 | ||
258 | /** | |
259 | * bus_add_device - add device to bus | |
260 | * @dev: device being added | |
261 | * | |
262 | * - Add the device to its bus's list of devices. | |
263 | * - Try to attach to driver. | |
264 | * - Create link to device's physical location. | |
265 | */ | |
266 | int bus_add_device(struct device * dev) | |
267 | { | |
268 | struct bus_type * bus = get_bus(dev->bus); | |
269 | int error = 0; | |
270 | ||
271 | if (bus) { | |
1da177e4 | 272 | pr_debug("bus %s: add device %s\n", bus->name, dev->bus_id); |
d377e85b | 273 | device_attach(dev); |
465c7a3a | 274 | klist_add_tail(&bus->klist_devices, &dev->knode_bus); |
d377e85b | 275 | error = device_add_attrs(bus, dev); |
ca2b94ba HR |
276 | if (!error) { |
277 | sysfs_create_link(&bus->devices.kobj, &dev->kobj, dev->bus_id); | |
278 | sysfs_create_link(&dev->kobj, &dev->bus->subsys.kset.kobj, "bus"); | |
279 | } | |
1da177e4 LT |
280 | } |
281 | return error; | |
282 | } | |
283 | ||
284 | /** | |
285 | * bus_remove_device - remove device from bus | |
286 | * @dev: device to be removed | |
287 | * | |
288 | * - Remove symlink from bus's directory. | |
289 | * - Delete device from bus's list. | |
290 | * - Detach from its driver. | |
291 | * - Drop reference taken in bus_add_device(). | |
292 | */ | |
293 | void bus_remove_device(struct device * dev) | |
294 | { | |
295 | if (dev->bus) { | |
296 | sysfs_remove_link(&dev->kobj, "bus"); | |
297 | sysfs_remove_link(&dev->bus->devices.kobj, dev->bus_id); | |
298 | device_remove_attrs(dev->bus, dev); | |
465c7a3a | 299 | klist_remove(&dev->knode_bus); |
1da177e4 LT |
300 | pr_debug("bus %s: remove device %s\n", dev->bus->name, dev->bus_id); |
301 | device_release_driver(dev); | |
1da177e4 LT |
302 | put_bus(dev->bus); |
303 | } | |
304 | } | |
305 | ||
306 | static int driver_add_attrs(struct bus_type * bus, struct device_driver * drv) | |
307 | { | |
308 | int error = 0; | |
309 | int i; | |
310 | ||
311 | if (bus->drv_attrs) { | |
312 | for (i = 0; attr_name(bus->drv_attrs[i]); i++) { | |
313 | error = driver_create_file(drv, &bus->drv_attrs[i]); | |
314 | if (error) | |
315 | goto Err; | |
316 | } | |
317 | } | |
318 | Done: | |
319 | return error; | |
320 | Err: | |
321 | while (--i >= 0) | |
322 | driver_remove_file(drv, &bus->drv_attrs[i]); | |
323 | goto Done; | |
324 | } | |
325 | ||
326 | ||
327 | static void driver_remove_attrs(struct bus_type * bus, struct device_driver * drv) | |
328 | { | |
329 | int i; | |
330 | ||
331 | if (bus->drv_attrs) { | |
332 | for (i = 0; attr_name(bus->drv_attrs[i]); i++) | |
333 | driver_remove_file(drv, &bus->drv_attrs[i]); | |
334 | } | |
335 | } | |
336 | ||
337 | ||
338 | /** | |
339 | * bus_add_driver - Add a driver to the bus. | |
340 | * @drv: driver. | |
341 | * | |
342 | */ | |
343 | int bus_add_driver(struct device_driver * drv) | |
344 | { | |
345 | struct bus_type * bus = get_bus(drv->bus); | |
346 | int error = 0; | |
347 | ||
348 | if (bus) { | |
349 | pr_debug("bus %s: add driver %s\n", bus->name, drv->name); | |
350 | error = kobject_set_name(&drv->kobj, "%s", drv->name); | |
351 | if (error) { | |
352 | put_bus(bus); | |
353 | return error; | |
354 | } | |
355 | drv->kobj.kset = &bus->drivers; | |
356 | if ((error = kobject_register(&drv->kobj))) { | |
357 | put_bus(bus); | |
358 | return error; | |
359 | } | |
360 | ||
1da177e4 | 361 | driver_attach(drv); |
38fdac3c | 362 | klist_add_tail(&bus->klist_drivers, &drv->knode_bus); |
1da177e4 LT |
363 | module_add_driver(drv->owner, drv); |
364 | ||
365 | driver_add_attrs(bus, drv); | |
366 | } | |
367 | return error; | |
368 | } | |
369 | ||
370 | ||
371 | /** | |
372 | * bus_remove_driver - delete driver from bus's knowledge. | |
373 | * @drv: driver. | |
374 | * | |
375 | * Detach the driver from the devices it controls, and remove | |
376 | * it from its bus's list of drivers. Finally, we drop the reference | |
377 | * to the bus we took in bus_add_driver(). | |
378 | */ | |
379 | ||
380 | void bus_remove_driver(struct device_driver * drv) | |
381 | { | |
382 | if (drv->bus) { | |
383 | driver_remove_attrs(drv->bus, drv); | |
38fdac3c | 384 | klist_remove(&drv->knode_bus); |
1da177e4 LT |
385 | pr_debug("bus %s: remove driver %s\n", drv->bus->name, drv->name); |
386 | driver_detach(drv); | |
1da177e4 LT |
387 | module_remove_driver(drv); |
388 | kobject_unregister(&drv->kobj); | |
389 | put_bus(drv->bus); | |
390 | } | |
391 | } | |
392 | ||
393 | ||
394 | /* Helper for bus_rescan_devices's iter */ | |
395 | static int bus_rescan_devices_helper(struct device *dev, void *data) | |
396 | { | |
397 | int *count = data; | |
398 | ||
ca2b94ba | 399 | if (!dev->driver && (device_attach(dev) > 0)) |
1da177e4 LT |
400 | (*count)++; |
401 | ||
402 | return 0; | |
403 | } | |
404 | ||
405 | ||
406 | /** | |
407 | * bus_rescan_devices - rescan devices on the bus for possible drivers | |
408 | * @bus: the bus to scan. | |
409 | * | |
410 | * This function will look for devices on the bus with no driver | |
411 | * attached and rescan it against existing drivers to see if it | |
412 | * matches any. Calls device_attach(). Returns the number of devices | |
413 | * that were sucessfully bound to a driver. | |
414 | */ | |
415 | int bus_rescan_devices(struct bus_type * bus) | |
416 | { | |
417 | int count = 0; | |
418 | ||
465c7a3a | 419 | bus_for_each_dev(bus, NULL, &count, bus_rescan_devices_helper); |
1da177e4 LT |
420 | |
421 | return count; | |
422 | } | |
423 | ||
424 | ||
425 | struct bus_type * get_bus(struct bus_type * bus) | |
426 | { | |
427 | return bus ? container_of(subsys_get(&bus->subsys), struct bus_type, subsys) : NULL; | |
428 | } | |
429 | ||
430 | void put_bus(struct bus_type * bus) | |
431 | { | |
432 | subsys_put(&bus->subsys); | |
433 | } | |
434 | ||
435 | ||
436 | /** | |
437 | * find_bus - locate bus by name. | |
438 | * @name: name of bus. | |
439 | * | |
440 | * Call kset_find_obj() to iterate over list of buses to | |
441 | * find a bus by name. Return bus if found. | |
442 | * | |
443 | * Note that kset_find_obj increments bus' reference count. | |
444 | */ | |
445 | ||
446 | struct bus_type * find_bus(char * name) | |
447 | { | |
448 | struct kobject * k = kset_find_obj(&bus_subsys.kset, name); | |
449 | return k ? to_bus(k) : NULL; | |
450 | } | |
451 | ||
452 | ||
453 | /** | |
454 | * bus_add_attrs - Add default attributes for this bus. | |
455 | * @bus: Bus that has just been registered. | |
456 | */ | |
457 | ||
458 | static int bus_add_attrs(struct bus_type * bus) | |
459 | { | |
460 | int error = 0; | |
461 | int i; | |
462 | ||
463 | if (bus->bus_attrs) { | |
464 | for (i = 0; attr_name(bus->bus_attrs[i]); i++) { | |
465 | if ((error = bus_create_file(bus,&bus->bus_attrs[i]))) | |
466 | goto Err; | |
467 | } | |
468 | } | |
469 | Done: | |
470 | return error; | |
471 | Err: | |
472 | while (--i >= 0) | |
473 | bus_remove_file(bus,&bus->bus_attrs[i]); | |
474 | goto Done; | |
475 | } | |
476 | ||
477 | static void bus_remove_attrs(struct bus_type * bus) | |
478 | { | |
479 | int i; | |
480 | ||
481 | if (bus->bus_attrs) { | |
482 | for (i = 0; attr_name(bus->bus_attrs[i]); i++) | |
483 | bus_remove_file(bus,&bus->bus_attrs[i]); | |
484 | } | |
485 | } | |
486 | ||
487 | /** | |
488 | * bus_register - register a bus with the system. | |
489 | * @bus: bus. | |
490 | * | |
491 | * Once we have that, we registered the bus with the kobject | |
492 | * infrastructure, then register the children subsystems it has: | |
493 | * the devices and drivers that belong to the bus. | |
494 | */ | |
495 | int bus_register(struct bus_type * bus) | |
496 | { | |
497 | int retval; | |
498 | ||
499 | retval = kobject_set_name(&bus->subsys.kset.kobj, "%s", bus->name); | |
500 | if (retval) | |
501 | goto out; | |
502 | ||
503 | subsys_set_kset(bus, bus_subsys); | |
504 | retval = subsystem_register(&bus->subsys); | |
505 | if (retval) | |
506 | goto out; | |
507 | ||
508 | kobject_set_name(&bus->devices.kobj, "devices"); | |
509 | bus->devices.subsys = &bus->subsys; | |
510 | retval = kset_register(&bus->devices); | |
511 | if (retval) | |
512 | goto bus_devices_fail; | |
513 | ||
514 | kobject_set_name(&bus->drivers.kobj, "drivers"); | |
515 | bus->drivers.subsys = &bus->subsys; | |
516 | bus->drivers.ktype = &ktype_driver; | |
517 | retval = kset_register(&bus->drivers); | |
518 | if (retval) | |
519 | goto bus_drivers_fail; | |
465c7a3a | 520 | |
521 | klist_init(&bus->klist_devices); | |
38fdac3c | 522 | klist_init(&bus->klist_drivers); |
1da177e4 LT |
523 | bus_add_attrs(bus); |
524 | ||
525 | pr_debug("bus type '%s' registered\n", bus->name); | |
526 | return 0; | |
527 | ||
528 | bus_drivers_fail: | |
529 | kset_unregister(&bus->devices); | |
530 | bus_devices_fail: | |
531 | subsystem_unregister(&bus->subsys); | |
532 | out: | |
533 | return retval; | |
534 | } | |
535 | ||
536 | ||
537 | /** | |
538 | * bus_unregister - remove a bus from the system | |
539 | * @bus: bus. | |
540 | * | |
541 | * Unregister the child subsystems and the bus itself. | |
542 | * Finally, we call put_bus() to release the refcount | |
543 | */ | |
544 | void bus_unregister(struct bus_type * bus) | |
545 | { | |
546 | pr_debug("bus %s: unregistering\n", bus->name); | |
547 | bus_remove_attrs(bus); | |
548 | kset_unregister(&bus->drivers); | |
549 | kset_unregister(&bus->devices); | |
550 | subsystem_unregister(&bus->subsys); | |
551 | } | |
552 | ||
553 | int __init buses_init(void) | |
554 | { | |
555 | return subsystem_register(&bus_subsys); | |
556 | } | |
557 | ||
558 | ||
559 | EXPORT_SYMBOL_GPL(bus_for_each_dev); | |
560 | EXPORT_SYMBOL_GPL(bus_for_each_drv); | |
561 | ||
1da177e4 LT |
562 | EXPORT_SYMBOL_GPL(bus_add_device); |
563 | EXPORT_SYMBOL_GPL(bus_remove_device); | |
564 | EXPORT_SYMBOL_GPL(bus_register); | |
565 | EXPORT_SYMBOL_GPL(bus_unregister); | |
566 | EXPORT_SYMBOL_GPL(bus_rescan_devices); | |
567 | EXPORT_SYMBOL_GPL(get_bus); | |
568 | EXPORT_SYMBOL_GPL(put_bus); | |
569 | EXPORT_SYMBOL_GPL(find_bus); | |
570 | ||
571 | EXPORT_SYMBOL_GPL(bus_create_file); | |
572 | EXPORT_SYMBOL_GPL(bus_remove_file); |