bus.c 18.3 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34
/*
 * bus.c - bus driver management
 *
 * Copyright (c) 2002-3 Patrick Mochel
 * Copyright (c) 2002-3 Open Source Development Labs
 *
 * This file is released under the GPLv2
 *
 */

#include <linux/device.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/string.h>
#include "base.h"
#include "power/power.h"

#define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
#define to_bus(obj) container_of(obj, struct bus_type, subsys.kset.kobj)

/*
 * sysfs bindings for drivers
 */

#define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
#define to_driver(obj) container_of(obj, struct device_driver, kobj)


static ssize_t
drv_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
{
	struct driver_attribute * drv_attr = to_drv_attr(attr);
	struct device_driver * drv = to_driver(kobj);
35
	ssize_t ret = -EIO;
L
Linus Torvalds 已提交
36 37 38 39 40 41 42 43 44 45 46 47

	if (drv_attr->show)
		ret = drv_attr->show(drv, buf);
	return ret;
}

static ssize_t
drv_attr_store(struct kobject * kobj, struct attribute * attr,
	       const char * buf, size_t count)
{
	struct driver_attribute * drv_attr = to_drv_attr(attr);
	struct device_driver * drv = to_driver(kobj);
48
	ssize_t ret = -EIO;
L
Linus Torvalds 已提交
49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131

	if (drv_attr->store)
		ret = drv_attr->store(drv, buf, count);
	return ret;
}

static struct sysfs_ops driver_sysfs_ops = {
	.show	= drv_attr_show,
	.store	= drv_attr_store,
};


static void driver_release(struct kobject * kobj)
{
	struct device_driver * drv = to_driver(kobj);
	complete(&drv->unloaded);
}

static struct kobj_type ktype_driver = {
	.sysfs_ops	= &driver_sysfs_ops,
	.release	= driver_release,
};


/*
 * sysfs bindings for buses
 */


static ssize_t
bus_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
{
	struct bus_attribute * bus_attr = to_bus_attr(attr);
	struct bus_type * bus = to_bus(kobj);
	ssize_t ret = 0;

	if (bus_attr->show)
		ret = bus_attr->show(bus, buf);
	return ret;
}

static ssize_t
bus_attr_store(struct kobject * kobj, struct attribute * attr,
	       const char * buf, size_t count)
{
	struct bus_attribute * bus_attr = to_bus_attr(attr);
	struct bus_type * bus = to_bus(kobj);
	ssize_t ret = 0;

	if (bus_attr->store)
		ret = bus_attr->store(bus, buf, count);
	return ret;
}

static struct sysfs_ops bus_sysfs_ops = {
	.show	= bus_attr_show,
	.store	= bus_attr_store,
};

int bus_create_file(struct bus_type * bus, struct bus_attribute * attr)
{
	int error;
	if (get_bus(bus)) {
		error = sysfs_create_file(&bus->subsys.kset.kobj, &attr->attr);
		put_bus(bus);
	} else
		error = -EINVAL;
	return error;
}

void bus_remove_file(struct bus_type * bus, struct bus_attribute * attr)
{
	if (get_bus(bus)) {
		sysfs_remove_file(&bus->subsys.kset.kobj, &attr->attr);
		put_bus(bus);
	}
}

static struct kobj_type ktype_bus = {
	.sysfs_ops	= &bus_sysfs_ops,

};

132
static decl_subsys(bus, &ktype_bus, NULL);
L
Linus Torvalds 已提交
133 134


135 136
#ifdef CONFIG_HOTPLUG

A
Alan Stern 已提交
137
/* Manually detach a device from its associated driver. */
138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154
static int driver_helper(struct device *dev, void *data)
{
	const char *name = data;

	if (strcmp(name, dev->bus_id) == 0)
		return 1;
	return 0;
}

static ssize_t driver_unbind(struct device_driver *drv,
			     const char *buf, size_t count)
{
	struct bus_type *bus = get_bus(drv->bus);
	struct device *dev;
	int err = -ENODEV;

	dev = bus_find_device(bus, NULL, (void *)buf, driver_helper);
A
Alan Stern 已提交
155
	if (dev && dev->driver == drv) {
156 157
		if (dev->parent)	/* Needed for USB */
			down(&dev->parent->sem);
158
		device_release_driver(dev);
159 160
		if (dev->parent)
			up(&dev->parent->sem);
161 162
		err = count;
	}
A
Alan Stern 已提交
163 164 165
	put_device(dev);
	put_bus(bus);
	return err;
166 167 168
}
static DRIVER_ATTR(unbind, S_IWUSR, NULL, driver_unbind);

169 170 171 172 173 174 175 176 177 178 179 180 181
/*
 * Manually attach a device to a driver.
 * Note: the driver must want to bind to the device,
 * it is not possible to override the driver's id table.
 */
static ssize_t driver_bind(struct device_driver *drv,
			   const char *buf, size_t count)
{
	struct bus_type *bus = get_bus(drv->bus);
	struct device *dev;
	int err = -ENODEV;

	dev = bus_find_device(bus, NULL, (void *)buf, driver_helper);
A
Alan Stern 已提交
182
	if (dev && dev->driver == NULL) {
183 184
		if (dev->parent)	/* Needed for USB */
			down(&dev->parent->sem);
185 186 187
		down(&dev->sem);
		err = driver_probe_device(drv, dev);
		up(&dev->sem);
188 189
		if (dev->parent)
			up(&dev->parent->sem);
190 191 192 193 194

		if (err > 0) 		/* success */
			err = count;
		else if (err == 0)	/* driver didn't accept device */
			err = -ENODEV;
195
	}
A
Alan Stern 已提交
196 197 198
	put_device(dev);
	put_bus(bus);
	return err;
199 200 201
}
static DRIVER_ATTR(bind, S_IWUSR, NULL, driver_bind);

202
#endif
203

204 205 206 207 208 209
static struct device * next_device(struct klist_iter * i)
{
	struct klist_node * n = klist_next(i);
	return n ? container_of(n, struct device, knode_bus) : NULL;
}

L
Linus Torvalds 已提交
210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232
/**
 *	bus_for_each_dev - device iterator.
 *	@bus:	bus type.
 *	@start:	device to start iterating from.
 *	@data:	data for the callback.
 *	@fn:	function to be called for each device.
 *
 *	Iterate over @bus's list of devices, and call @fn for each,
 *	passing it @data. If @start is not NULL, we use that device to
 *	begin iterating from.
 *
 *	We check the return of @fn each time. If it returns anything
 *	other than 0, we break out and return that value.
 *
 *	NOTE: The device that returns a non-zero value is not retained
 *	in any way, nor is its refcount incremented. If the caller needs
 *	to retain this data, it should do, and increment the reference
 *	count in the supplied callback.
 */

int bus_for_each_dev(struct bus_type * bus, struct device * start,
		     void * data, int (*fn)(struct device *, void *))
{
233 234 235
	struct klist_iter i;
	struct device * dev;
	int error = 0;
L
Linus Torvalds 已提交
236

237 238 239 240 241 242 243 244 245
	if (!bus)
		return -EINVAL;

	klist_iter_init_node(&bus->klist_devices, &i,
			     (start ? &start->knode_bus : NULL));
	while ((dev = next_device(&i)) && !error)
		error = fn(dev, data);
	klist_iter_exit(&i);
	return error;
L
Linus Torvalds 已提交
246 247
}

248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280
/**
 * bus_find_device - device iterator for locating a particular device.
 * @bus: bus type
 * @start: Device to begin with
 * @data: Data to pass to match function
 * @match: Callback function to check device
 *
 * This is similar to the bus_for_each_dev() function above, but it
 * returns a reference to a device that is 'found' for later use, as
 * determined by the @match callback.
 *
 * The callback should return 0 if the device doesn't match and non-zero
 * if it does.  If the callback returns non-zero, this function will
 * return to the caller and not iterate over any more devices.
 */
struct device * bus_find_device(struct bus_type *bus,
				struct device *start, void *data,
				int (*match)(struct device *, void *))
{
	struct klist_iter i;
	struct device *dev;

	if (!bus)
		return NULL;

	klist_iter_init_node(&bus->klist_devices, &i,
			     (start ? &start->knode_bus : NULL));
	while ((dev = next_device(&i)))
		if (match(dev, data) && get_device(dev))
			break;
	klist_iter_exit(&i);
	return dev;
}
281 282 283 284 285 286 287 288


static struct device_driver * next_driver(struct klist_iter * i)
{
	struct klist_node * n = klist_next(i);
	return n ? container_of(n, struct device_driver, knode_bus) : NULL;
}

L
Linus Torvalds 已提交
289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311
/**
 *	bus_for_each_drv - driver iterator
 *	@bus:	bus we're dealing with.
 *	@start:	driver to start iterating on.
 *	@data:	data to pass to the callback.
 *	@fn:	function to call for each driver.
 *
 *	This is nearly identical to the device iterator above.
 *	We iterate over each driver that belongs to @bus, and call
 *	@fn for each. If @fn returns anything but 0, we break out
 *	and return it. If @start is not NULL, we use it as the head
 *	of the list.
 *
 *	NOTE: we don't return the driver that returns a non-zero
 *	value, nor do we leave the reference count incremented for that
 *	driver. If the caller needs to know that info, it must set it
 *	in the callback. It must also be sure to increment the refcount
 *	so it doesn't disappear before returning to the caller.
 */

int bus_for_each_drv(struct bus_type * bus, struct device_driver * start,
		     void * data, int (*fn)(struct device_driver *, void *))
{
312 313 314
	struct klist_iter i;
	struct device_driver * drv;
	int error = 0;
L
Linus Torvalds 已提交
315

316 317 318 319 320 321 322 323 324
	if (!bus)
		return -EINVAL;

	klist_iter_init_node(&bus->klist_drivers, &i,
			     start ? &start->knode_bus : NULL);
	while ((drv = next_driver(&i)) && !error)
		error = fn(drv, data);
	klist_iter_exit(&i);
	return error;
L
Linus Torvalds 已提交
325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363
}

static int device_add_attrs(struct bus_type * bus, struct device * dev)
{
	int error = 0;
	int i;

	if (bus->dev_attrs) {
		for (i = 0; attr_name(bus->dev_attrs[i]); i++) {
			error = device_create_file(dev,&bus->dev_attrs[i]);
			if (error)
				goto Err;
		}
	}
 Done:
	return error;
 Err:
	while (--i >= 0)
		device_remove_file(dev,&bus->dev_attrs[i]);
	goto Done;
}


static void device_remove_attrs(struct bus_type * bus, struct device * dev)
{
	int i;

	if (bus->dev_attrs) {
		for (i = 0; attr_name(bus->dev_attrs[i]); i++)
			device_remove_file(dev,&bus->dev_attrs[i]);
	}
}


/**
 *	bus_add_device - add device to bus
 *	@dev:	device being added
 *
 *	- Add the device to its bus's list of devices.
364
 *	- Create link to device's bus.
L
Linus Torvalds 已提交
365 366 367 368 369 370 371 372
 */
int bus_add_device(struct device * dev)
{
	struct bus_type * bus = get_bus(dev->bus);
	int error = 0;

	if (bus) {
		pr_debug("bus %s: add device %s\n", bus->name, dev->bus_id);
373
		error = device_add_attrs(bus, dev);
A
Andrew Morton 已提交
374 375 376 377 378 379 380 381 382 383 384 385
		if (error)
			goto out;
		error = sysfs_create_link(&bus->devices.kobj,
						&dev->kobj, dev->bus_id);
		if (error)
			goto out;
		error = sysfs_create_link(&dev->kobj,
				&dev->bus->subsys.kset.kobj, "subsystem");
		if (error)
			goto out;
		error = sysfs_create_link(&dev->kobj,
				&dev->bus->subsys.kset.kobj, "bus");
L
Linus Torvalds 已提交
386
	}
A
Andrew Morton 已提交
387
out:
L
Linus Torvalds 已提交
388 389 390
	return error;
}

391 392 393 394
/**
 *	bus_attach_device - add device to bus
 *	@dev:	device tried to attach to a driver
 *
395
 *	- Add device to bus's list of devices.
396 397
 *	- Try to attach to driver.
 */
A
Andrew Morton 已提交
398
int bus_attach_device(struct device * dev)
399
{
A
Andrew Morton 已提交
400 401
	struct bus_type *bus = dev->bus;
	int ret = 0;
402 403

	if (bus) {
404
		dev->is_registered = 1;
A
Andrew Morton 已提交
405 406 407 408
		ret = device_attach(dev);
		if (ret >= 0) {
			klist_add_tail(&dev->knode_bus, &bus->klist_devices);
			ret = 0;
409 410
		} else
			dev->is_registered = 0;
411
	}
A
Andrew Morton 已提交
412
	return ret;
413 414
}

L
Linus Torvalds 已提交
415 416 417 418 419 420 421 422 423 424 425 426
/**
 *	bus_remove_device - remove device from bus
 *	@dev:	device to be removed
 *
 *	- Remove symlink from bus's directory.
 *	- Delete device from bus's list.
 *	- Detach from its driver.
 *	- Drop reference taken in bus_add_device().
 */
void bus_remove_device(struct device * dev)
{
	if (dev->bus) {
427
		sysfs_remove_link(&dev->kobj, "subsystem");
L
Linus Torvalds 已提交
428 429 430
		sysfs_remove_link(&dev->kobj, "bus");
		sysfs_remove_link(&dev->bus->devices.kobj, dev->bus_id);
		device_remove_attrs(dev->bus, dev);
431 432
		dev->is_registered = 0;
		klist_del(&dev->knode_bus);
L
Linus Torvalds 已提交
433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469
		pr_debug("bus %s: remove device %s\n", dev->bus->name, dev->bus_id);
		device_release_driver(dev);
		put_bus(dev->bus);
	}
}

static int driver_add_attrs(struct bus_type * bus, struct device_driver * drv)
{
	int error = 0;
	int i;

	if (bus->drv_attrs) {
		for (i = 0; attr_name(bus->drv_attrs[i]); i++) {
			error = driver_create_file(drv, &bus->drv_attrs[i]);
			if (error)
				goto Err;
		}
	}
 Done:
	return error;
 Err:
	while (--i >= 0)
		driver_remove_file(drv, &bus->drv_attrs[i]);
	goto Done;
}


static void driver_remove_attrs(struct bus_type * bus, struct device_driver * drv)
{
	int i;

	if (bus->drv_attrs) {
		for (i = 0; attr_name(bus->drv_attrs[i]); i++)
			driver_remove_file(drv, &bus->drv_attrs[i]);
	}
}

470 471 472 473 474
#ifdef CONFIG_HOTPLUG
/*
 * Thanks to drivers making their tables __devinit, we can't allow manual
 * bind and unbind from userspace unless CONFIG_HOTPLUG is enabled.
 */
A
Andrew Morton 已提交
475
static int __must_check add_bind_files(struct device_driver *drv)
476
{
A
Andrew Morton 已提交
477 478 479 480 481 482 483 484 485
	int ret;

	ret = driver_create_file(drv, &driver_attr_unbind);
	if (ret == 0) {
		ret = driver_create_file(drv, &driver_attr_bind);
		if (ret)
			driver_remove_file(drv, &driver_attr_unbind);
	}
	return ret;
486 487 488 489 490 491 492 493
}

static void remove_bind_files(struct device_driver *drv)
{
	driver_remove_file(drv, &driver_attr_bind);
	driver_remove_file(drv, &driver_attr_unbind);
}
#else
494
static inline int add_bind_files(struct device_driver *drv) { return 0; }
495 496
static inline void remove_bind_files(struct device_driver *drv) {}
#endif
L
Linus Torvalds 已提交
497 498 499 500 501 502

/**
 *	bus_add_driver - Add a driver to the bus.
 *	@drv:	driver.
 *
 */
A
Andrew Morton 已提交
503
int bus_add_driver(struct device_driver *drv)
L
Linus Torvalds 已提交
504 505 506 507 508 509 510
{
	struct bus_type * bus = get_bus(drv->bus);
	int error = 0;

	if (bus) {
		pr_debug("bus %s: add driver %s\n", bus->name, drv->name);
		error = kobject_set_name(&drv->kobj, "%s", drv->name);
A
Andrew Morton 已提交
511 512
		if (error)
			goto out_put_bus;
L
Linus Torvalds 已提交
513
		drv->kobj.kset = &bus->drivers;
A
Andrew Morton 已提交
514 515
		if ((error = kobject_register(&drv->kobj)))
			goto out_put_bus;
L
Linus Torvalds 已提交
516

A
Andrew Morton 已提交
517 518 519
		error = driver_attach(drv);
		if (error)
			goto out_unregister;
520
		klist_add_tail(&drv->knode_bus, &bus->klist_drivers);
L
Linus Torvalds 已提交
521 522
		module_add_driver(drv->owner, drv);

A
Andrew Morton 已提交
523 524 525 526 527 528 529 530 531 532 533 534
		error = driver_add_attrs(bus, drv);
		if (error) {
			/* How the hell do we get out of this pickle? Give up */
			printk(KERN_ERR "%s: driver_add_attrs(%s) failed\n",
				__FUNCTION__, drv->name);
		}
		error = add_bind_files(drv);
		if (error) {
			/* Ditto */
			printk(KERN_ERR "%s: add_bind_files(%s) failed\n",
				__FUNCTION__, drv->name);
		}
L
Linus Torvalds 已提交
535 536
	}
	return error;
A
Andrew Morton 已提交
537 538 539 540 541
out_unregister:
	kobject_unregister(&drv->kobj);
out_put_bus:
	put_bus(bus);
	return error;
L
Linus Torvalds 已提交
542 543 544 545 546 547 548 549 550 551 552 553 554 555
}

/**
 *	bus_remove_driver - delete driver from bus's knowledge.
 *	@drv:	driver.
 *
 *	Detach the driver from the devices it controls, and remove
 *	it from its bus's list of drivers. Finally, we drop the reference
 *	to the bus we took in bus_add_driver().
 */

void bus_remove_driver(struct device_driver * drv)
{
	if (drv->bus) {
556
		remove_bind_files(drv);
L
Linus Torvalds 已提交
557
		driver_remove_attrs(drv->bus, drv);
558
		klist_remove(&drv->knode_bus);
L
Linus Torvalds 已提交
559 560 561 562 563 564 565 566 567 568
		pr_debug("bus %s: remove driver %s\n", drv->bus->name, drv->name);
		driver_detach(drv);
		module_remove_driver(drv);
		kobject_unregister(&drv->kobj);
		put_bus(drv->bus);
	}
}


/* Helper for bus_rescan_devices's iter */
A
Andrew Morton 已提交
569 570
static int __must_check bus_rescan_devices_helper(struct device *dev,
						void *data)
L
Linus Torvalds 已提交
571
{
A
Andrew Morton 已提交
572 573
	int ret = 0;

574 575 576
	if (!dev->driver) {
		if (dev->parent)	/* Needed for USB */
			down(&dev->parent->sem);
A
Andrew Morton 已提交
577
		ret = device_attach(dev);
578 579
		if (dev->parent)
			up(&dev->parent->sem);
A
Andrew Morton 已提交
580 581
		if (ret > 0)
			ret = 0;
582
	}
A
Andrew Morton 已提交
583
	return ret < 0 ? ret : 0;
L
Linus Torvalds 已提交
584 585 586
}

/**
587 588
 * bus_rescan_devices - rescan devices on the bus for possible drivers
 * @bus: the bus to scan.
L
Linus Torvalds 已提交
589
 *
590 591 592
 * This function will look for devices on the bus with no driver
 * attached and rescan it against existing drivers to see if it matches
 * any by calling device_attach() for the unbound devices.
L
Linus Torvalds 已提交
593
 */
A
Andrew Morton 已提交
594
int bus_rescan_devices(struct bus_type * bus)
L
Linus Torvalds 已提交
595
{
A
Andrew Morton 已提交
596
	return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
L
Linus Torvalds 已提交
597 598
}

599 600 601 602 603 604 605 606 607
/**
 * device_reprobe - remove driver for a device and probe for a new driver
 * @dev: the device to reprobe
 *
 * This function detaches the attached driver (if any) for the given
 * device and restarts the driver probing process.  It is intended
 * to use if probing criteria changed during a devices lifetime and
 * driver attachment should change accordingly.
 */
A
Andrew Morton 已提交
608
int device_reprobe(struct device *dev)
609 610 611 612 613 614 615 616
{
	if (dev->driver) {
		if (dev->parent)        /* Needed for USB */
			down(&dev->parent->sem);
		device_release_driver(dev);
		if (dev->parent)
			up(&dev->parent->sem);
	}
A
Andrew Morton 已提交
617
	return bus_rescan_devices_helper(dev, NULL);
618 619
}
EXPORT_SYMBOL_GPL(device_reprobe);
L
Linus Torvalds 已提交
620

A
Andrew Morton 已提交
621
struct bus_type *get_bus(struct bus_type *bus)
L
Linus Torvalds 已提交
622
{
A
Andrew Morton 已提交
623 624
	return bus ? container_of(subsys_get(&bus->subsys),
				struct bus_type, subsys) : NULL;
L
Linus Torvalds 已提交
625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641
}

void put_bus(struct bus_type * bus)
{
	subsys_put(&bus->subsys);
}


/**
 *	find_bus - locate bus by name.
 *	@name:	name of bus.
 *
 *	Call kset_find_obj() to iterate over list of buses to
 *	find a bus by name. Return bus if found.
 *
 *	Note that kset_find_obj increments bus' reference count.
 */
642
#if 0
L
Linus Torvalds 已提交
643 644 645 646 647
struct bus_type * find_bus(char * name)
{
	struct kobject * k = kset_find_obj(&bus_subsys.kset, name);
	return k ? to_bus(k) : NULL;
}
648
#endif  /*  0  */
L
Linus Torvalds 已提交
649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684


/**
 *	bus_add_attrs - Add default attributes for this bus.
 *	@bus:	Bus that has just been registered.
 */

static int bus_add_attrs(struct bus_type * bus)
{
	int error = 0;
	int i;

	if (bus->bus_attrs) {
		for (i = 0; attr_name(bus->bus_attrs[i]); i++) {
			if ((error = bus_create_file(bus,&bus->bus_attrs[i])))
				goto Err;
		}
	}
 Done:
	return error;
 Err:
	while (--i >= 0)
		bus_remove_file(bus,&bus->bus_attrs[i]);
	goto Done;
}

static void bus_remove_attrs(struct bus_type * bus)
{
	int i;

	if (bus->bus_attrs) {
		for (i = 0; attr_name(bus->bus_attrs[i]); i++)
			bus_remove_file(bus,&bus->bus_attrs[i]);
	}
}

685 686 687 688 689 690 691 692 693 694 695 696 697 698
static void klist_devices_get(struct klist_node *n)
{
	struct device *dev = container_of(n, struct device, knode_bus);

	get_device(dev);
}

static void klist_devices_put(struct klist_node *n)
{
	struct device *dev = container_of(n, struct device, knode_bus);

	put_device(dev);
}

L
Linus Torvalds 已提交
699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731
/**
 *	bus_register - register a bus with the system.
 *	@bus:	bus.
 *
 *	Once we have that, we registered the bus with the kobject
 *	infrastructure, then register the children subsystems it has:
 *	the devices and drivers that belong to the bus.
 */
int bus_register(struct bus_type * bus)
{
	int retval;

	retval = kobject_set_name(&bus->subsys.kset.kobj, "%s", bus->name);
	if (retval)
		goto out;

	subsys_set_kset(bus, bus_subsys);
	retval = subsystem_register(&bus->subsys);
	if (retval)
		goto out;

	kobject_set_name(&bus->devices.kobj, "devices");
	bus->devices.subsys = &bus->subsys;
	retval = kset_register(&bus->devices);
	if (retval)
		goto bus_devices_fail;

	kobject_set_name(&bus->drivers.kobj, "drivers");
	bus->drivers.subsys = &bus->subsys;
	bus->drivers.ktype = &ktype_driver;
	retval = kset_register(&bus->drivers);
	if (retval)
		goto bus_drivers_fail;
732

733
	klist_init(&bus->klist_devices, klist_devices_get, klist_devices_put);
734
	klist_init(&bus->klist_drivers, NULL, NULL);
L
Linus Torvalds 已提交
735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771
	bus_add_attrs(bus);

	pr_debug("bus type '%s' registered\n", bus->name);
	return 0;

bus_drivers_fail:
	kset_unregister(&bus->devices);
bus_devices_fail:
	subsystem_unregister(&bus->subsys);
out:
	return retval;
}


/**
 *	bus_unregister - remove a bus from the system
 *	@bus:	bus.
 *
 *	Unregister the child subsystems and the bus itself.
 *	Finally, we call put_bus() to release the refcount
 */
void bus_unregister(struct bus_type * bus)
{
	pr_debug("bus %s: unregistering\n", bus->name);
	bus_remove_attrs(bus);
	kset_unregister(&bus->drivers);
	kset_unregister(&bus->devices);
	subsystem_unregister(&bus->subsys);
}

int __init buses_init(void)
{
	return subsystem_register(&bus_subsys);
}


EXPORT_SYMBOL_GPL(bus_for_each_dev);
772
EXPORT_SYMBOL_GPL(bus_find_device);
L
Linus Torvalds 已提交
773 774 775 776 777 778 779 780
EXPORT_SYMBOL_GPL(bus_for_each_drv);

EXPORT_SYMBOL_GPL(bus_register);
EXPORT_SYMBOL_GPL(bus_unregister);
EXPORT_SYMBOL_GPL(bus_rescan_devices);

EXPORT_SYMBOL_GPL(bus_create_file);
EXPORT_SYMBOL_GPL(bus_remove_file);