ia64/linux-2.6.18-xen.hg

view drivers/base/bus.c @ 881:e9f508296fc7

pcie io space multiplex: backport of bus event notification patch

back port of 116af378201ef793424cd10508ccf18b06d8a021 and
ec0676ee28528dc8dda13a93ee4b1f215a0c2f9d.

commit 116af378201ef793424cd10508ccf18b06d8a021
Author: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: Wed Oct 25 13:44:59 2006 +1000

Driver core: add notification of bus events

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>


commit ec0676ee28528dc8dda13a93ee4b1f215a0c2f9d
Author: Alan Stern <stern@rowland.harvard.edu>
Date: Fri Dec 5 14:10:31 2008 -0500

Driver core: move the bus notifier call points

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
author Keir Fraser <keir.fraser@citrix.com>
date Thu May 28 09:56:11 2009 +0100 (2009-05-28)
parents 831230e53067
children
line source
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 */
11 #include <linux/device.h>
12 #include <linux/module.h>
13 #include <linux/errno.h>
14 #include <linux/init.h>
15 #include <linux/string.h>
16 #include "base.h"
17 #include "power/power.h"
19 #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
20 #define to_bus(obj) container_of(obj, struct bus_type, subsys.kset.kobj)
22 /*
23 * sysfs bindings for drivers
24 */
26 #define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
27 #define to_driver(obj) container_of(obj, struct device_driver, kobj)
30 static ssize_t
31 drv_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
32 {
33 struct driver_attribute * drv_attr = to_drv_attr(attr);
34 struct device_driver * drv = to_driver(kobj);
35 ssize_t ret = -EIO;
37 if (drv_attr->show)
38 ret = drv_attr->show(drv, buf);
39 return ret;
40 }
42 static ssize_t
43 drv_attr_store(struct kobject * kobj, struct attribute * attr,
44 const char * buf, size_t count)
45 {
46 struct driver_attribute * drv_attr = to_drv_attr(attr);
47 struct device_driver * drv = to_driver(kobj);
48 ssize_t ret = -EIO;
50 if (drv_attr->store)
51 ret = drv_attr->store(drv, buf, count);
52 return ret;
53 }
55 static struct sysfs_ops driver_sysfs_ops = {
56 .show = drv_attr_show,
57 .store = drv_attr_store,
58 };
61 static void driver_release(struct kobject * kobj)
62 {
63 struct device_driver * drv = to_driver(kobj);
64 complete(&drv->unloaded);
65 }
67 static struct kobj_type ktype_driver = {
68 .sysfs_ops = &driver_sysfs_ops,
69 .release = driver_release,
70 };
73 /*
74 * sysfs bindings for buses
75 */
78 static ssize_t
79 bus_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
80 {
81 struct bus_attribute * bus_attr = to_bus_attr(attr);
82 struct bus_type * bus = to_bus(kobj);
83 ssize_t ret = 0;
85 if (bus_attr->show)
86 ret = bus_attr->show(bus, buf);
87 return ret;
88 }
90 static ssize_t
91 bus_attr_store(struct kobject * kobj, struct attribute * attr,
92 const char * buf, size_t count)
93 {
94 struct bus_attribute * bus_attr = to_bus_attr(attr);
95 struct bus_type * bus = to_bus(kobj);
96 ssize_t ret = 0;
98 if (bus_attr->store)
99 ret = bus_attr->store(bus, buf, count);
100 return ret;
101 }
103 static struct sysfs_ops bus_sysfs_ops = {
104 .show = bus_attr_show,
105 .store = bus_attr_store,
106 };
108 int bus_create_file(struct bus_type * bus, struct bus_attribute * attr)
109 {
110 int error;
111 if (get_bus(bus)) {
112 error = sysfs_create_file(&bus->subsys.kset.kobj, &attr->attr);
113 put_bus(bus);
114 } else
115 error = -EINVAL;
116 return error;
117 }
119 void bus_remove_file(struct bus_type * bus, struct bus_attribute * attr)
120 {
121 if (get_bus(bus)) {
122 sysfs_remove_file(&bus->subsys.kset.kobj, &attr->attr);
123 put_bus(bus);
124 }
125 }
127 static struct kobj_type ktype_bus = {
128 .sysfs_ops = &bus_sysfs_ops,
130 };
132 static decl_subsys(bus, &ktype_bus, NULL);
135 #ifdef CONFIG_HOTPLUG
137 /* Manually detach a device from its associated driver. */
138 static int driver_helper(struct device *dev, void *data)
139 {
140 const char *name = data;
142 if (strcmp(name, dev->bus_id) == 0)
143 return 1;
144 return 0;
145 }
147 static ssize_t driver_unbind(struct device_driver *drv,
148 const char *buf, size_t count)
149 {
150 struct bus_type *bus = get_bus(drv->bus);
151 struct device *dev;
152 int err = -ENODEV;
154 dev = bus_find_device(bus, NULL, (void *)buf, driver_helper);
155 if (dev && dev->driver == drv) {
156 if (dev->parent) /* Needed for USB */
157 down(&dev->parent->sem);
158 device_release_driver(dev);
159 if (dev->parent)
160 up(&dev->parent->sem);
161 err = count;
162 }
163 put_device(dev);
164 put_bus(bus);
165 return err;
166 }
167 static DRIVER_ATTR(unbind, S_IWUSR, NULL, driver_unbind);
169 /*
170 * Manually attach a device to a driver.
171 * Note: the driver must want to bind to the device,
172 * it is not possible to override the driver's id table.
173 */
174 static ssize_t driver_bind(struct device_driver *drv,
175 const char *buf, size_t count)
176 {
177 struct bus_type *bus = get_bus(drv->bus);
178 struct device *dev;
179 int err = -ENODEV;
181 dev = bus_find_device(bus, NULL, (void *)buf, driver_helper);
182 if (dev && dev->driver == NULL) {
183 if (dev->parent) /* Needed for USB */
184 down(&dev->parent->sem);
185 down(&dev->sem);
186 err = driver_probe_device(drv, dev);
187 up(&dev->sem);
188 if (dev->parent)
189 up(&dev->parent->sem);
191 if (err > 0) /* success */
192 err = count;
193 else if (err == 0) /* driver didn't accept device */
194 err = -ENODEV;
195 }
196 put_device(dev);
197 put_bus(bus);
198 return err;
199 }
200 static DRIVER_ATTR(bind, S_IWUSR, NULL, driver_bind);
202 #endif
204 static struct device * next_device(struct klist_iter * i)
205 {
206 struct klist_node * n = klist_next(i);
207 return n ? container_of(n, struct device, knode_bus) : NULL;
208 }
210 /**
211 * bus_for_each_dev - device iterator.
212 * @bus: bus type.
213 * @start: device to start iterating from.
214 * @data: data for the callback.
215 * @fn: function to be called for each device.
216 *
217 * Iterate over @bus's list of devices, and call @fn for each,
218 * passing it @data. If @start is not NULL, we use that device to
219 * begin iterating from.
220 *
221 * We check the return of @fn each time. If it returns anything
222 * other than 0, we break out and return that value.
223 *
224 * NOTE: The device that returns a non-zero value is not retained
225 * in any way, nor is its refcount incremented. If the caller needs
226 * to retain this data, it should do, and increment the reference
227 * count in the supplied callback.
228 */
230 int bus_for_each_dev(struct bus_type * bus, struct device * start,
231 void * data, int (*fn)(struct device *, void *))
232 {
233 struct klist_iter i;
234 struct device * dev;
235 int error = 0;
237 if (!bus)
238 return -EINVAL;
240 klist_iter_init_node(&bus->klist_devices, &i,
241 (start ? &start->knode_bus : NULL));
242 while ((dev = next_device(&i)) && !error)
243 error = fn(dev, data);
244 klist_iter_exit(&i);
245 return error;
246 }
248 /**
249 * bus_find_device - device iterator for locating a particular device.
250 * @bus: bus type
251 * @start: Device to begin with
252 * @data: Data to pass to match function
253 * @match: Callback function to check device
254 *
255 * This is similar to the bus_for_each_dev() function above, but it
256 * returns a reference to a device that is 'found' for later use, as
257 * determined by the @match callback.
258 *
259 * The callback should return 0 if the device doesn't match and non-zero
260 * if it does. If the callback returns non-zero, this function will
261 * return to the caller and not iterate over any more devices.
262 */
263 struct device * bus_find_device(struct bus_type *bus,
264 struct device *start, void *data,
265 int (*match)(struct device *, void *))
266 {
267 struct klist_iter i;
268 struct device *dev;
270 if (!bus)
271 return NULL;
273 klist_iter_init_node(&bus->klist_devices, &i,
274 (start ? &start->knode_bus : NULL));
275 while ((dev = next_device(&i)))
276 if (match(dev, data) && get_device(dev))
277 break;
278 klist_iter_exit(&i);
279 return dev;
280 }
283 static struct device_driver * next_driver(struct klist_iter * i)
284 {
285 struct klist_node * n = klist_next(i);
286 return n ? container_of(n, struct device_driver, knode_bus) : NULL;
287 }
289 /**
290 * bus_for_each_drv - driver iterator
291 * @bus: bus we're dealing with.
292 * @start: driver to start iterating on.
293 * @data: data to pass to the callback.
294 * @fn: function to call for each driver.
295 *
296 * This is nearly identical to the device iterator above.
297 * We iterate over each driver that belongs to @bus, and call
298 * @fn for each. If @fn returns anything but 0, we break out
299 * and return it. If @start is not NULL, we use it as the head
300 * of the list.
301 *
302 * NOTE: we don't return the driver that returns a non-zero
303 * value, nor do we leave the reference count incremented for that
304 * driver. If the caller needs to know that info, it must set it
305 * in the callback. It must also be sure to increment the refcount
306 * so it doesn't disappear before returning to the caller.
307 */
309 int bus_for_each_drv(struct bus_type * bus, struct device_driver * start,
310 void * data, int (*fn)(struct device_driver *, void *))
311 {
312 struct klist_iter i;
313 struct device_driver * drv;
314 int error = 0;
316 if (!bus)
317 return -EINVAL;
319 klist_iter_init_node(&bus->klist_drivers, &i,
320 start ? &start->knode_bus : NULL);
321 while ((drv = next_driver(&i)) && !error)
322 error = fn(drv, data);
323 klist_iter_exit(&i);
324 return error;
325 }
327 static int device_add_attrs(struct bus_type * bus, struct device * dev)
328 {
329 int error = 0;
330 int i;
332 if (bus->dev_attrs) {
333 for (i = 0; attr_name(bus->dev_attrs[i]); i++) {
334 error = device_create_file(dev,&bus->dev_attrs[i]);
335 if (error)
336 goto Err;
337 }
338 }
339 Done:
340 return error;
341 Err:
342 while (--i >= 0)
343 device_remove_file(dev,&bus->dev_attrs[i]);
344 goto Done;
345 }
348 static void device_remove_attrs(struct bus_type * bus, struct device * dev)
349 {
350 int i;
352 if (bus->dev_attrs) {
353 for (i = 0; attr_name(bus->dev_attrs[i]); i++)
354 device_remove_file(dev,&bus->dev_attrs[i]);
355 }
356 }
359 /**
360 * bus_add_device - add device to bus
361 * @dev: device being added
362 *
363 * - Add the device to its bus's list of devices.
364 * - Create link to device's bus.
365 */
366 int bus_add_device(struct device * dev)
367 {
368 struct bus_type * bus = get_bus(dev->bus);
369 int error = 0;
371 if (bus) {
372 pr_debug("bus %s: add device %s\n", bus->name, dev->bus_id);
373 error = device_add_attrs(bus, dev);
374 if (!error) {
375 sysfs_create_link(&bus->devices.kobj, &dev->kobj, dev->bus_id);
376 sysfs_create_link(&dev->kobj, &dev->bus->subsys.kset.kobj, "subsystem");
377 sysfs_create_link(&dev->kobj, &dev->bus->subsys.kset.kobj, "bus");
378 }
379 }
380 return error;
381 }
383 /**
384 * bus_attach_device - add device to bus
385 * @dev: device tried to attach to a driver
386 *
387 * - Try to attach to driver.
388 */
389 void bus_attach_device(struct device * dev)
390 {
391 struct bus_type * bus = dev->bus;
393 if (bus) {
394 device_attach(dev);
395 klist_add_tail(&dev->knode_bus, &bus->klist_devices);
396 }
397 }
399 /**
400 * bus_remove_device - remove device from bus
401 * @dev: device to be removed
402 *
403 * - Remove symlink from bus's directory.
404 * - Delete device from bus's list.
405 * - Detach from its driver.
406 * - Drop reference taken in bus_add_device().
407 */
408 void bus_remove_device(struct device * dev)
409 {
410 if (dev->bus) {
411 sysfs_remove_link(&dev->kobj, "subsystem");
412 sysfs_remove_link(&dev->kobj, "bus");
413 sysfs_remove_link(&dev->bus->devices.kobj, dev->bus_id);
414 device_remove_attrs(dev->bus, dev);
415 klist_remove(&dev->knode_bus);
416 pr_debug("bus %s: remove device %s\n", dev->bus->name, dev->bus_id);
417 device_release_driver(dev);
418 put_bus(dev->bus);
419 }
420 }
422 static int driver_add_attrs(struct bus_type * bus, struct device_driver * drv)
423 {
424 int error = 0;
425 int i;
427 if (bus->drv_attrs) {
428 for (i = 0; attr_name(bus->drv_attrs[i]); i++) {
429 error = driver_create_file(drv, &bus->drv_attrs[i]);
430 if (error)
431 goto Err;
432 }
433 }
434 Done:
435 return error;
436 Err:
437 while (--i >= 0)
438 driver_remove_file(drv, &bus->drv_attrs[i]);
439 goto Done;
440 }
443 static void driver_remove_attrs(struct bus_type * bus, struct device_driver * drv)
444 {
445 int i;
447 if (bus->drv_attrs) {
448 for (i = 0; attr_name(bus->drv_attrs[i]); i++)
449 driver_remove_file(drv, &bus->drv_attrs[i]);
450 }
451 }
453 #ifdef CONFIG_HOTPLUG
454 /*
455 * Thanks to drivers making their tables __devinit, we can't allow manual
456 * bind and unbind from userspace unless CONFIG_HOTPLUG is enabled.
457 */
458 static void add_bind_files(struct device_driver *drv)
459 {
460 driver_create_file(drv, &driver_attr_unbind);
461 driver_create_file(drv, &driver_attr_bind);
462 }
464 static void remove_bind_files(struct device_driver *drv)
465 {
466 driver_remove_file(drv, &driver_attr_bind);
467 driver_remove_file(drv, &driver_attr_unbind);
468 }
469 #else
470 static inline void add_bind_files(struct device_driver *drv) {}
471 static inline void remove_bind_files(struct device_driver *drv) {}
472 #endif
474 /**
475 * bus_add_driver - Add a driver to the bus.
476 * @drv: driver.
477 *
478 */
479 int bus_add_driver(struct device_driver * drv)
480 {
481 struct bus_type * bus = get_bus(drv->bus);
482 int error = 0;
484 if (bus) {
485 pr_debug("bus %s: add driver %s\n", bus->name, drv->name);
486 error = kobject_set_name(&drv->kobj, "%s", drv->name);
487 if (error) {
488 put_bus(bus);
489 return error;
490 }
491 drv->kobj.kset = &bus->drivers;
492 if ((error = kobject_register(&drv->kobj))) {
493 put_bus(bus);
494 return error;
495 }
497 driver_attach(drv);
498 klist_add_tail(&drv->knode_bus, &bus->klist_drivers);
499 module_add_driver(drv->owner, drv);
501 driver_add_attrs(bus, drv);
502 add_bind_files(drv);
503 }
504 return error;
505 }
508 /**
509 * bus_remove_driver - delete driver from bus's knowledge.
510 * @drv: driver.
511 *
512 * Detach the driver from the devices it controls, and remove
513 * it from its bus's list of drivers. Finally, we drop the reference
514 * to the bus we took in bus_add_driver().
515 */
517 void bus_remove_driver(struct device_driver * drv)
518 {
519 if (drv->bus) {
520 remove_bind_files(drv);
521 driver_remove_attrs(drv->bus, drv);
522 klist_remove(&drv->knode_bus);
523 pr_debug("bus %s: remove driver %s\n", drv->bus->name, drv->name);
524 driver_detach(drv);
525 module_remove_driver(drv);
526 kobject_unregister(&drv->kobj);
527 put_bus(drv->bus);
528 }
529 }
532 /* Helper for bus_rescan_devices's iter */
533 static int bus_rescan_devices_helper(struct device *dev, void *data)
534 {
535 if (!dev->driver) {
536 if (dev->parent) /* Needed for USB */
537 down(&dev->parent->sem);
538 device_attach(dev);
539 if (dev->parent)
540 up(&dev->parent->sem);
541 }
542 return 0;
543 }
545 /**
546 * bus_rescan_devices - rescan devices on the bus for possible drivers
547 * @bus: the bus to scan.
548 *
549 * This function will look for devices on the bus with no driver
550 * attached and rescan it against existing drivers to see if it matches
551 * any by calling device_attach() for the unbound devices.
552 */
553 void bus_rescan_devices(struct bus_type * bus)
554 {
555 bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
556 }
558 /**
559 * device_reprobe - remove driver for a device and probe for a new driver
560 * @dev: the device to reprobe
561 *
562 * This function detaches the attached driver (if any) for the given
563 * device and restarts the driver probing process. It is intended
564 * to use if probing criteria changed during a devices lifetime and
565 * driver attachment should change accordingly.
566 */
567 void device_reprobe(struct device *dev)
568 {
569 if (dev->driver) {
570 if (dev->parent) /* Needed for USB */
571 down(&dev->parent->sem);
572 device_release_driver(dev);
573 if (dev->parent)
574 up(&dev->parent->sem);
575 }
577 bus_rescan_devices_helper(dev, NULL);
578 }
579 EXPORT_SYMBOL_GPL(device_reprobe);
581 struct bus_type * get_bus(struct bus_type * bus)
582 {
583 return bus ? container_of(subsys_get(&bus->subsys), struct bus_type, subsys) : NULL;
584 }
586 void put_bus(struct bus_type * bus)
587 {
588 subsys_put(&bus->subsys);
589 }
592 /**
593 * find_bus - locate bus by name.
594 * @name: name of bus.
595 *
596 * Call kset_find_obj() to iterate over list of buses to
597 * find a bus by name. Return bus if found.
598 *
599 * Note that kset_find_obj increments bus' reference count.
600 */
601 #if 0
602 struct bus_type * find_bus(char * name)
603 {
604 struct kobject * k = kset_find_obj(&bus_subsys.kset, name);
605 return k ? to_bus(k) : NULL;
606 }
607 #endif /* 0 */
610 /**
611 * bus_add_attrs - Add default attributes for this bus.
612 * @bus: Bus that has just been registered.
613 */
615 static int bus_add_attrs(struct bus_type * bus)
616 {
617 int error = 0;
618 int i;
620 if (bus->bus_attrs) {
621 for (i = 0; attr_name(bus->bus_attrs[i]); i++) {
622 if ((error = bus_create_file(bus,&bus->bus_attrs[i])))
623 goto Err;
624 }
625 }
626 Done:
627 return error;
628 Err:
629 while (--i >= 0)
630 bus_remove_file(bus,&bus->bus_attrs[i]);
631 goto Done;
632 }
634 static void bus_remove_attrs(struct bus_type * bus)
635 {
636 int i;
638 if (bus->bus_attrs) {
639 for (i = 0; attr_name(bus->bus_attrs[i]); i++)
640 bus_remove_file(bus,&bus->bus_attrs[i]);
641 }
642 }
644 static void klist_devices_get(struct klist_node *n)
645 {
646 struct device *dev = container_of(n, struct device, knode_bus);
648 get_device(dev);
649 }
651 static void klist_devices_put(struct klist_node *n)
652 {
653 struct device *dev = container_of(n, struct device, knode_bus);
655 put_device(dev);
656 }
658 static void klist_drivers_get(struct klist_node *n)
659 {
660 struct device_driver *drv = container_of(n, struct device_driver,
661 knode_bus);
663 get_driver(drv);
664 }
666 static void klist_drivers_put(struct klist_node *n)
667 {
668 struct device_driver *drv = container_of(n, struct device_driver,
669 knode_bus);
671 put_driver(drv);
672 }
674 /**
675 * bus_register - register a bus with the system.
676 * @bus: bus.
677 *
678 * Once we have that, we registered the bus with the kobject
679 * infrastructure, then register the children subsystems it has:
680 * the devices and drivers that belong to the bus.
681 */
682 int bus_register(struct bus_type * bus)
683 {
684 int retval;
686 BLOCKING_INIT_NOTIFIER_HEAD(&bus->bus_notifier);
688 retval = kobject_set_name(&bus->subsys.kset.kobj, "%s", bus->name);
689 if (retval)
690 goto out;
692 subsys_set_kset(bus, bus_subsys);
693 retval = subsystem_register(&bus->subsys);
694 if (retval)
695 goto out;
697 kobject_set_name(&bus->devices.kobj, "devices");
698 bus->devices.subsys = &bus->subsys;
699 retval = kset_register(&bus->devices);
700 if (retval)
701 goto bus_devices_fail;
703 kobject_set_name(&bus->drivers.kobj, "drivers");
704 bus->drivers.subsys = &bus->subsys;
705 bus->drivers.ktype = &ktype_driver;
706 retval = kset_register(&bus->drivers);
707 if (retval)
708 goto bus_drivers_fail;
710 klist_init(&bus->klist_devices, klist_devices_get, klist_devices_put);
711 klist_init(&bus->klist_drivers, klist_drivers_get, klist_drivers_put);
712 bus_add_attrs(bus);
714 pr_debug("bus type '%s' registered\n", bus->name);
715 return 0;
717 bus_drivers_fail:
718 kset_unregister(&bus->devices);
719 bus_devices_fail:
720 subsystem_unregister(&bus->subsys);
721 out:
722 return retval;
723 }
726 /**
727 * bus_unregister - remove a bus from the system
728 * @bus: bus.
729 *
730 * Unregister the child subsystems and the bus itself.
731 * Finally, we call put_bus() to release the refcount
732 */
733 void bus_unregister(struct bus_type * bus)
734 {
735 pr_debug("bus %s: unregistering\n", bus->name);
736 bus_remove_attrs(bus);
737 kset_unregister(&bus->drivers);
738 kset_unregister(&bus->devices);
739 subsystem_unregister(&bus->subsys);
740 }
742 int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
743 {
744 return blocking_notifier_chain_register(&bus->bus_notifier, nb);
745 }
746 EXPORT_SYMBOL_GPL(bus_register_notifier);
748 int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
749 {
750 return blocking_notifier_chain_unregister(&bus->bus_notifier, nb);
751 }
752 EXPORT_SYMBOL_GPL(bus_unregister_notifier);
754 int __init buses_init(void)
755 {
756 return subsystem_register(&bus_subsys);
757 }
760 EXPORT_SYMBOL_GPL(bus_for_each_dev);
761 EXPORT_SYMBOL_GPL(bus_find_device);
762 EXPORT_SYMBOL_GPL(bus_for_each_drv);
764 EXPORT_SYMBOL_GPL(bus_register);
765 EXPORT_SYMBOL_GPL(bus_unregister);
766 EXPORT_SYMBOL_GPL(bus_rescan_devices);
768 EXPORT_SYMBOL_GPL(bus_create_file);
769 EXPORT_SYMBOL_GPL(bus_remove_file);