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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/base/bus.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'drivers/base/bus.c')
-rw-r--r--drivers/base/bus.c770
1 files changed, 770 insertions, 0 deletions
diff --git a/drivers/base/bus.c b/drivers/base/bus.c
new file mode 100644
index 000000000000..f4fa27315fb4
--- /dev/null
+++ b/drivers/base/bus.c
@@ -0,0 +1,770 @@
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
20#define to_dev(node) container_of(node, struct device, bus_list)
21#define to_drv(node) container_of(node, struct device_driver, kobj.entry)
22
23#define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
24#define to_bus(obj) container_of(obj, struct bus_type, subsys.kset.kobj)
25
26/*
27 * sysfs bindings for drivers
28 */
29
30#define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
31#define to_driver(obj) container_of(obj, struct device_driver, kobj)
32
33
34static ssize_t
35drv_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
36{
37 struct driver_attribute * drv_attr = to_drv_attr(attr);
38 struct device_driver * drv = to_driver(kobj);
39 ssize_t ret = 0;
40
41 if (drv_attr->show)
42 ret = drv_attr->show(drv, buf);
43 return ret;
44}
45
46static ssize_t
47drv_attr_store(struct kobject * kobj, struct attribute * attr,
48 const char * buf, size_t count)
49{
50 struct driver_attribute * drv_attr = to_drv_attr(attr);
51 struct device_driver * drv = to_driver(kobj);
52 ssize_t ret = 0;
53
54 if (drv_attr->store)
55 ret = drv_attr->store(drv, buf, count);
56 return ret;
57}
58
59static struct sysfs_ops driver_sysfs_ops = {
60 .show = drv_attr_show,
61 .store = drv_attr_store,
62};
63
64
65static void driver_release(struct kobject * kobj)
66{
67 struct device_driver * drv = to_driver(kobj);
68 complete(&drv->unloaded);
69}
70
71static struct kobj_type ktype_driver = {
72 .sysfs_ops = &driver_sysfs_ops,
73 .release = driver_release,
74};
75
76
77/*
78 * sysfs bindings for buses
79 */
80
81
82static ssize_t
83bus_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
84{
85 struct bus_attribute * bus_attr = to_bus_attr(attr);
86 struct bus_type * bus = to_bus(kobj);
87 ssize_t ret = 0;
88
89 if (bus_attr->show)
90 ret = bus_attr->show(bus, buf);
91 return ret;
92}
93
94static ssize_t
95bus_attr_store(struct kobject * kobj, struct attribute * attr,
96 const char * buf, size_t count)
97{
98 struct bus_attribute * bus_attr = to_bus_attr(attr);
99 struct bus_type * bus = to_bus(kobj);
100 ssize_t ret = 0;
101
102 if (bus_attr->store)
103 ret = bus_attr->store(bus, buf, count);
104 return ret;
105}
106
107static struct sysfs_ops bus_sysfs_ops = {
108 .show = bus_attr_show,
109 .store = bus_attr_store,
110};
111
112int bus_create_file(struct bus_type * bus, struct bus_attribute * attr)
113{
114 int error;
115 if (get_bus(bus)) {
116 error = sysfs_create_file(&bus->subsys.kset.kobj, &attr->attr);
117 put_bus(bus);
118 } else
119 error = -EINVAL;
120 return error;
121}
122
123void bus_remove_file(struct bus_type * bus, struct bus_attribute * attr)
124{
125 if (get_bus(bus)) {
126 sysfs_remove_file(&bus->subsys.kset.kobj, &attr->attr);
127 put_bus(bus);
128 }
129}
130
131static struct kobj_type ktype_bus = {
132 .sysfs_ops = &bus_sysfs_ops,
133
134};
135
136decl_subsys(bus, &ktype_bus, NULL);
137
138static int __bus_for_each_dev(struct bus_type *bus, struct device *start,
139 void *data, int (*fn)(struct device *, void *))
140{
141 struct list_head *head;
142 struct device *dev;
143 int error = 0;
144
145 if (!(bus = get_bus(bus)))
146 return -EINVAL;
147
148 head = &bus->devices.list;
149 dev = list_prepare_entry(start, head, bus_list);
150 list_for_each_entry_continue(dev, head, bus_list) {
151 get_device(dev);
152 error = fn(dev, data);
153 put_device(dev);
154 if (error)
155 break;
156 }
157 put_bus(bus);
158 return error;
159}
160
161static int __bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
162 void * data, int (*fn)(struct device_driver *, void *))
163{
164 struct list_head *head;
165 struct device_driver *drv;
166 int error = 0;
167
168 if (!(bus = get_bus(bus)))
169 return -EINVAL;
170
171 head = &bus->drivers.list;
172 drv = list_prepare_entry(start, head, kobj.entry);
173 list_for_each_entry_continue(drv, head, kobj.entry) {
174 get_driver(drv);
175 error = fn(drv, data);
176 put_driver(drv);
177 if (error)
178 break;
179 }
180 put_bus(bus);
181 return error;
182}
183
184/**
185 * bus_for_each_dev - device iterator.
186 * @bus: bus type.
187 * @start: device to start iterating from.
188 * @data: data for the callback.
189 * @fn: function to be called for each device.
190 *
191 * Iterate over @bus's list of devices, and call @fn for each,
192 * passing it @data. If @start is not NULL, we use that device to
193 * begin iterating from.
194 *
195 * We check the return of @fn each time. If it returns anything
196 * other than 0, we break out and return that value.
197 *
198 * NOTE: The device that returns a non-zero value is not retained
199 * in any way, nor is its refcount incremented. If the caller needs
200 * to retain this data, it should do, and increment the reference
201 * count in the supplied callback.
202 */
203
204int bus_for_each_dev(struct bus_type * bus, struct device * start,
205 void * data, int (*fn)(struct device *, void *))
206{
207 int ret;
208
209 down_read(&bus->subsys.rwsem);
210 ret = __bus_for_each_dev(bus, start, data, fn);
211 up_read(&bus->subsys.rwsem);
212 return ret;
213}
214
215/**
216 * bus_for_each_drv - driver iterator
217 * @bus: bus we're dealing with.
218 * @start: driver to start iterating on.
219 * @data: data to pass to the callback.
220 * @fn: function to call for each driver.
221 *
222 * This is nearly identical to the device iterator above.
223 * We iterate over each driver that belongs to @bus, and call
224 * @fn for each. If @fn returns anything but 0, we break out
225 * and return it. If @start is not NULL, we use it as the head
226 * of the list.
227 *
228 * NOTE: we don't return the driver that returns a non-zero
229 * value, nor do we leave the reference count incremented for that
230 * driver. If the caller needs to know that info, it must set it
231 * in the callback. It must also be sure to increment the refcount
232 * so it doesn't disappear before returning to the caller.
233 */
234
235int bus_for_each_drv(struct bus_type * bus, struct device_driver * start,
236 void * data, int (*fn)(struct device_driver *, void *))
237{
238 int ret;
239
240 down_read(&bus->subsys.rwsem);
241 ret = __bus_for_each_drv(bus, start, data, fn);
242 up_read(&bus->subsys.rwsem);
243 return ret;
244}
245
246/**
247 * device_bind_driver - bind a driver to one device.
248 * @dev: device.
249 *
250 * Allow manual attachment of a driver to a device.
251 * Caller must have already set @dev->driver.
252 *
253 * Note that this does not modify the bus reference count
254 * nor take the bus's rwsem. Please verify those are accounted
255 * for before calling this. (It is ok to call with no other effort
256 * from a driver's probe() method.)
257 */
258
259void device_bind_driver(struct device * dev)
260{
261 pr_debug("bound device '%s' to driver '%s'\n",
262 dev->bus_id, dev->driver->name);
263 list_add_tail(&dev->driver_list, &dev->driver->devices);
264 sysfs_create_link(&dev->driver->kobj, &dev->kobj,
265 kobject_name(&dev->kobj));
266 sysfs_create_link(&dev->kobj, &dev->driver->kobj, "driver");
267}
268
269
270/**
271 * driver_probe_device - attempt to bind device & driver.
272 * @drv: driver.
273 * @dev: device.
274 *
275 * First, we call the bus's match function, if one present, which
276 * should compare the device IDs the driver supports with the
277 * device IDs of the device. Note we don't do this ourselves
278 * because we don't know the format of the ID structures, nor what
279 * is to be considered a match and what is not.
280 *
281 * If we find a match, we call @drv->probe(@dev) if it exists, and
282 * call device_bind_driver() above.
283 */
284int driver_probe_device(struct device_driver * drv, struct device * dev)
285{
286 if (drv->bus->match && !drv->bus->match(dev, drv))
287 return -ENODEV;
288
289 dev->driver = drv;
290 if (drv->probe) {
291 int error = drv->probe(dev);
292 if (error) {
293 dev->driver = NULL;
294 return error;
295 }
296 }
297
298 device_bind_driver(dev);
299 return 0;
300}
301
302
303/**
304 * device_attach - try to attach device to a driver.
305 * @dev: device.
306 *
307 * Walk the list of drivers that the bus has and call
308 * driver_probe_device() for each pair. If a compatible
309 * pair is found, break out and return.
310 */
311int device_attach(struct device * dev)
312{
313 struct bus_type * bus = dev->bus;
314 struct list_head * entry;
315 int error;
316
317 if (dev->driver) {
318 device_bind_driver(dev);
319 return 1;
320 }
321
322 if (bus->match) {
323 list_for_each(entry, &bus->drivers.list) {
324 struct device_driver * drv = to_drv(entry);
325 error = driver_probe_device(drv, dev);
326 if (!error)
327 /* success, driver matched */
328 return 1;
329 if (error != -ENODEV && error != -ENXIO)
330 /* driver matched but the probe failed */
331 printk(KERN_WARNING
332 "%s: probe of %s failed with error %d\n",
333 drv->name, dev->bus_id, error);
334 }
335 }
336
337 return 0;
338}
339
340
341/**
342 * driver_attach - try to bind driver to devices.
343 * @drv: driver.
344 *
345 * Walk the list of devices that the bus has on it and try to
346 * match the driver with each one. If driver_probe_device()
347 * returns 0 and the @dev->driver is set, we've found a
348 * compatible pair.
349 *
350 * Note that we ignore the -ENODEV error from driver_probe_device(),
351 * since it's perfectly valid for a driver not to bind to any devices.
352 */
353void driver_attach(struct device_driver * drv)
354{
355 struct bus_type * bus = drv->bus;
356 struct list_head * entry;
357 int error;
358
359 if (!bus->match)
360 return;
361
362 list_for_each(entry, &bus->devices.list) {
363 struct device * dev = container_of(entry, struct device, bus_list);
364 if (!dev->driver) {
365 error = driver_probe_device(drv, dev);
366 if (error && (error != -ENODEV))
367 /* driver matched but the probe failed */
368 printk(KERN_WARNING
369 "%s: probe of %s failed with error %d\n",
370 drv->name, dev->bus_id, error);
371 }
372 }
373}
374
375
376/**
377 * device_release_driver - manually detach device from driver.
378 * @dev: device.
379 *
380 * Manually detach device from driver.
381 * Note that this is called without incrementing the bus
382 * reference count nor taking the bus's rwsem. Be sure that
383 * those are accounted for before calling this function.
384 */
385
386void device_release_driver(struct device * dev)
387{
388 struct device_driver * drv = dev->driver;
389 if (drv) {
390 sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
391 sysfs_remove_link(&dev->kobj, "driver");
392 list_del_init(&dev->driver_list);
393 device_detach_shutdown(dev);
394 if (drv->remove)
395 drv->remove(dev);
396 dev->driver = NULL;
397 }
398}
399
400
401/**
402 * driver_detach - detach driver from all devices it controls.
403 * @drv: driver.
404 */
405
406static void driver_detach(struct device_driver * drv)
407{
408 struct list_head * entry, * next;
409 list_for_each_safe(entry, next, &drv->devices) {
410 struct device * dev = container_of(entry, struct device, driver_list);
411 device_release_driver(dev);
412 }
413}
414
415static int device_add_attrs(struct bus_type * bus, struct device * dev)
416{
417 int error = 0;
418 int i;
419
420 if (bus->dev_attrs) {
421 for (i = 0; attr_name(bus->dev_attrs[i]); i++) {
422 error = device_create_file(dev,&bus->dev_attrs[i]);
423 if (error)
424 goto Err;
425 }
426 }
427 Done:
428 return error;
429 Err:
430 while (--i >= 0)
431 device_remove_file(dev,&bus->dev_attrs[i]);
432 goto Done;
433}
434
435
436static void device_remove_attrs(struct bus_type * bus, struct device * dev)
437{
438 int i;
439
440 if (bus->dev_attrs) {
441 for (i = 0; attr_name(bus->dev_attrs[i]); i++)
442 device_remove_file(dev,&bus->dev_attrs[i]);
443 }
444}
445
446
447/**
448 * bus_add_device - add device to bus
449 * @dev: device being added
450 *
451 * - Add the device to its bus's list of devices.
452 * - Try to attach to driver.
453 * - Create link to device's physical location.
454 */
455int bus_add_device(struct device * dev)
456{
457 struct bus_type * bus = get_bus(dev->bus);
458 int error = 0;
459
460 if (bus) {
461 down_write(&dev->bus->subsys.rwsem);
462 pr_debug("bus %s: add device %s\n", bus->name, dev->bus_id);
463 list_add_tail(&dev->bus_list, &dev->bus->devices.list);
464 device_attach(dev);
465 up_write(&dev->bus->subsys.rwsem);
466 device_add_attrs(bus, dev);
467 sysfs_create_link(&bus->devices.kobj, &dev->kobj, dev->bus_id);
468 sysfs_create_link(&dev->kobj, &dev->bus->subsys.kset.kobj, "bus");
469 }
470 return error;
471}
472
473/**
474 * bus_remove_device - remove device from bus
475 * @dev: device to be removed
476 *
477 * - Remove symlink from bus's directory.
478 * - Delete device from bus's list.
479 * - Detach from its driver.
480 * - Drop reference taken in bus_add_device().
481 */
482void bus_remove_device(struct device * dev)
483{
484 if (dev->bus) {
485 sysfs_remove_link(&dev->kobj, "bus");
486 sysfs_remove_link(&dev->bus->devices.kobj, dev->bus_id);
487 device_remove_attrs(dev->bus, dev);
488 down_write(&dev->bus->subsys.rwsem);
489 pr_debug("bus %s: remove device %s\n", dev->bus->name, dev->bus_id);
490 device_release_driver(dev);
491 list_del_init(&dev->bus_list);
492 up_write(&dev->bus->subsys.rwsem);
493 put_bus(dev->bus);
494 }
495}
496
497static int driver_add_attrs(struct bus_type * bus, struct device_driver * drv)
498{
499 int error = 0;
500 int i;
501
502 if (bus->drv_attrs) {
503 for (i = 0; attr_name(bus->drv_attrs[i]); i++) {
504 error = driver_create_file(drv, &bus->drv_attrs[i]);
505 if (error)
506 goto Err;
507 }
508 }
509 Done:
510 return error;
511 Err:
512 while (--i >= 0)
513 driver_remove_file(drv, &bus->drv_attrs[i]);
514 goto Done;
515}
516
517
518static void driver_remove_attrs(struct bus_type * bus, struct device_driver * drv)
519{
520 int i;
521
522 if (bus->drv_attrs) {
523 for (i = 0; attr_name(bus->drv_attrs[i]); i++)
524 driver_remove_file(drv, &bus->drv_attrs[i]);
525 }
526}
527
528
529/**
530 * bus_add_driver - Add a driver to the bus.
531 * @drv: driver.
532 *
533 */
534int bus_add_driver(struct device_driver * drv)
535{
536 struct bus_type * bus = get_bus(drv->bus);
537 int error = 0;
538
539 if (bus) {
540 pr_debug("bus %s: add driver %s\n", bus->name, drv->name);
541 error = kobject_set_name(&drv->kobj, "%s", drv->name);
542 if (error) {
543 put_bus(bus);
544 return error;
545 }
546 drv->kobj.kset = &bus->drivers;
547 if ((error = kobject_register(&drv->kobj))) {
548 put_bus(bus);
549 return error;
550 }
551
552 down_write(&bus->subsys.rwsem);
553 driver_attach(drv);
554 up_write(&bus->subsys.rwsem);
555 module_add_driver(drv->owner, drv);
556
557 driver_add_attrs(bus, drv);
558 }
559 return error;
560}
561
562
563/**
564 * bus_remove_driver - delete driver from bus's knowledge.
565 * @drv: driver.
566 *
567 * Detach the driver from the devices it controls, and remove
568 * it from its bus's list of drivers. Finally, we drop the reference
569 * to the bus we took in bus_add_driver().
570 */
571
572void bus_remove_driver(struct device_driver * drv)
573{
574 if (drv->bus) {
575 driver_remove_attrs(drv->bus, drv);
576 down_write(&drv->bus->subsys.rwsem);
577 pr_debug("bus %s: remove driver %s\n", drv->bus->name, drv->name);
578 driver_detach(drv);
579 up_write(&drv->bus->subsys.rwsem);
580 module_remove_driver(drv);
581 kobject_unregister(&drv->kobj);
582 put_bus(drv->bus);
583 }
584}
585
586
587/* Helper for bus_rescan_devices's iter */
588static int bus_rescan_devices_helper(struct device *dev, void *data)
589{
590 int *count = data;
591
592 if (!dev->driver && device_attach(dev))
593 (*count)++;
594
595 return 0;
596}
597
598
599/**
600 * bus_rescan_devices - rescan devices on the bus for possible drivers
601 * @bus: the bus to scan.
602 *
603 * This function will look for devices on the bus with no driver
604 * attached and rescan it against existing drivers to see if it
605 * matches any. Calls device_attach(). Returns the number of devices
606 * that were sucessfully bound to a driver.
607 */
608int bus_rescan_devices(struct bus_type * bus)
609{
610 int count = 0;
611
612 down_write(&bus->subsys.rwsem);
613 __bus_for_each_dev(bus, NULL, &count, bus_rescan_devices_helper);
614 up_write(&bus->subsys.rwsem);
615
616 return count;
617}
618
619
620struct bus_type * get_bus(struct bus_type * bus)
621{
622 return bus ? container_of(subsys_get(&bus->subsys), struct bus_type, subsys) : NULL;
623}
624
625void put_bus(struct bus_type * bus)
626{
627 subsys_put(&bus->subsys);
628}
629
630
631/**
632 * find_bus - locate bus by name.
633 * @name: name of bus.
634 *
635 * Call kset_find_obj() to iterate over list of buses to
636 * find a bus by name. Return bus if found.
637 *
638 * Note that kset_find_obj increments bus' reference count.
639 */
640
641struct bus_type * find_bus(char * name)
642{
643 struct kobject * k = kset_find_obj(&bus_subsys.kset, name);
644 return k ? to_bus(k) : NULL;
645}
646
647
648/**
649 * bus_add_attrs - Add default attributes for this bus.
650 * @bus: Bus that has just been registered.
651 */
652
653static int bus_add_attrs(struct bus_type * bus)
654{
655 int error = 0;
656 int i;
657
658 if (bus->bus_attrs) {
659 for (i = 0; attr_name(bus->bus_attrs[i]); i++) {
660 if ((error = bus_create_file(bus,&bus->bus_attrs[i])))
661 goto Err;
662 }
663 }
664 Done:
665 return error;
666 Err:
667 while (--i >= 0)
668 bus_remove_file(bus,&bus->bus_attrs[i]);
669 goto Done;
670}
671
672static void bus_remove_attrs(struct bus_type * bus)
673{
674 int i;
675
676 if (bus->bus_attrs) {
677 for (i = 0; attr_name(bus->bus_attrs[i]); i++)
678 bus_remove_file(bus,&bus->bus_attrs[i]);
679 }
680}
681
682/**
683 * bus_register - register a bus with the system.
684 * @bus: bus.
685 *
686 * Once we have that, we registered the bus with the kobject
687 * infrastructure, then register the children subsystems it has:
688 * the devices and drivers that belong to the bus.
689 */
690int bus_register(struct bus_type * bus)
691{
692 int retval;
693
694 retval = kobject_set_name(&bus->subsys.kset.kobj, "%s", bus->name);
695 if (retval)
696 goto out;
697
698 subsys_set_kset(bus, bus_subsys);
699 retval = subsystem_register(&bus->subsys);
700 if (retval)
701 goto out;
702
703 kobject_set_name(&bus->devices.kobj, "devices");
704 bus->devices.subsys = &bus->subsys;
705 retval = kset_register(&bus->devices);
706 if (retval)
707 goto bus_devices_fail;
708
709 kobject_set_name(&bus->drivers.kobj, "drivers");
710 bus->drivers.subsys = &bus->subsys;
711 bus->drivers.ktype = &ktype_driver;
712 retval = kset_register(&bus->drivers);
713 if (retval)
714 goto bus_drivers_fail;
715 bus_add_attrs(bus);
716
717 pr_debug("bus type '%s' registered\n", bus->name);
718 return 0;
719
720bus_drivers_fail:
721 kset_unregister(&bus->devices);
722bus_devices_fail:
723 subsystem_unregister(&bus->subsys);
724out:
725 return retval;
726}
727
728
729/**
730 * bus_unregister - remove a bus from the system
731 * @bus: bus.
732 *
733 * Unregister the child subsystems and the bus itself.
734 * Finally, we call put_bus() to release the refcount
735 */
736void bus_unregister(struct bus_type * bus)
737{
738 pr_debug("bus %s: unregistering\n", bus->name);
739 bus_remove_attrs(bus);
740 kset_unregister(&bus->drivers);
741 kset_unregister(&bus->devices);
742 subsystem_unregister(&bus->subsys);
743}
744
745int __init buses_init(void)
746{
747 return subsystem_register(&bus_subsys);
748}
749
750
751EXPORT_SYMBOL_GPL(bus_for_each_dev);
752EXPORT_SYMBOL_GPL(bus_for_each_drv);
753
754EXPORT_SYMBOL_GPL(driver_probe_device);
755EXPORT_SYMBOL_GPL(device_bind_driver);
756EXPORT_SYMBOL_GPL(device_release_driver);
757EXPORT_SYMBOL_GPL(device_attach);
758EXPORT_SYMBOL_GPL(driver_attach);
759
760EXPORT_SYMBOL_GPL(bus_add_device);
761EXPORT_SYMBOL_GPL(bus_remove_device);
762EXPORT_SYMBOL_GPL(bus_register);
763EXPORT_SYMBOL_GPL(bus_unregister);
764EXPORT_SYMBOL_GPL(bus_rescan_devices);
765EXPORT_SYMBOL_GPL(get_bus);
766EXPORT_SYMBOL_GPL(put_bus);
767EXPORT_SYMBOL_GPL(find_bus);
768
769EXPORT_SYMBOL_GPL(bus_create_file);
770EXPORT_SYMBOL_GPL(bus_remove_file);