bus.c 23.9 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5
/*
 * bus.c - bus driver management
 *
 * Copyright (c) 2002-3 Patrick Mochel
 * Copyright (c) 2002-3 Open Source Development Labs
6 7
 * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de>
 * Copyright (c) 2007 Novell Inc.
L
Linus Torvalds 已提交
8 9 10 11 12 13 14 15 16 17 18 19 20 21
 *
 * 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)
22
#define to_bus(obj) container_of(obj, struct bus_type_private, subsys.kobj)
L
Linus Torvalds 已提交
23 24 25 26 27 28 29 30

/*
 * sysfs bindings for drivers
 */

#define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)


31 32 33
static int __must_check bus_rescan_devices_helper(struct device *dev,
						void *data);

G
Greg Kroah-Hartman 已提交
34 35
static struct bus_type *bus_get(struct bus_type *bus)
{
36 37 38 39 40
	if (bus) {
		kset_get(&bus->p->subsys);
		return bus;
	}
	return NULL;
G
Greg Kroah-Hartman 已提交
41 42
}

G
Greg Kroah-Hartman 已提交
43 44
static void bus_put(struct bus_type *bus)
{
45 46
	if (bus)
		kset_put(&bus->p->subsys);
G
Greg Kroah-Hartman 已提交
47 48
}

49 50
static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr,
			     char *buf)
L
Linus Torvalds 已提交
51
{
52
	struct driver_attribute *drv_attr = to_drv_attr(attr);
53
	struct driver_private *drv_priv = to_driver(kobj);
54
	ssize_t ret = -EIO;
L
Linus Torvalds 已提交
55 56

	if (drv_attr->show)
57
		ret = drv_attr->show(drv_priv->driver, buf);
L
Linus Torvalds 已提交
58 59 60
	return ret;
}

61 62
static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr,
			      const char *buf, size_t count)
L
Linus Torvalds 已提交
63
{
64
	struct driver_attribute *drv_attr = to_drv_attr(attr);
65
	struct driver_private *drv_priv = to_driver(kobj);
66
	ssize_t ret = -EIO;
L
Linus Torvalds 已提交
67 68

	if (drv_attr->store)
69
		ret = drv_attr->store(drv_priv->driver, buf, count);
L
Linus Torvalds 已提交
70 71 72 73 74 75 76 77
	return ret;
}

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

78
static void driver_release(struct kobject *kobj)
L
Linus Torvalds 已提交
79
{
80 81
	struct driver_private *drv_priv = to_driver(kobj);

82
	pr_debug("driver: '%s': %s\n", kobject_name(kobj), __FUNCTION__);
83
	kfree(drv_priv);
L
Linus Torvalds 已提交
84 85
}

86
static struct kobj_type driver_ktype = {
L
Linus Torvalds 已提交
87 88 89 90 91 92 93
	.sysfs_ops	= &driver_sysfs_ops,
	.release	= driver_release,
};

/*
 * sysfs bindings for buses
 */
94 95
static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr,
			     char *buf)
L
Linus Torvalds 已提交
96
{
97
	struct bus_attribute *bus_attr = to_bus_attr(attr);
98
	struct bus_type_private *bus_priv = to_bus(kobj);
L
Linus Torvalds 已提交
99 100 101
	ssize_t ret = 0;

	if (bus_attr->show)
102
		ret = bus_attr->show(bus_priv->bus, buf);
L
Linus Torvalds 已提交
103 104 105
	return ret;
}

106 107
static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr,
			      const char *buf, size_t count)
L
Linus Torvalds 已提交
108
{
109
	struct bus_attribute *bus_attr = to_bus_attr(attr);
110
	struct bus_type_private *bus_priv = to_bus(kobj);
L
Linus Torvalds 已提交
111 112 113
	ssize_t ret = 0;

	if (bus_attr->store)
114
		ret = bus_attr->store(bus_priv->bus, buf, count);
L
Linus Torvalds 已提交
115 116 117 118 119 120 121 122
	return ret;
}

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

123
int bus_create_file(struct bus_type *bus, struct bus_attribute *attr)
L
Linus Torvalds 已提交
124 125
{
	int error;
G
Greg Kroah-Hartman 已提交
126
	if (bus_get(bus)) {
127
		error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr);
G
Greg Kroah-Hartman 已提交
128
		bus_put(bus);
L
Linus Torvalds 已提交
129 130 131 132
	} else
		error = -EINVAL;
	return error;
}
133
EXPORT_SYMBOL_GPL(bus_create_file);
L
Linus Torvalds 已提交
134

135
void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr)
L
Linus Torvalds 已提交
136
{
G
Greg Kroah-Hartman 已提交
137
	if (bus_get(bus)) {
138
		sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr);
G
Greg Kroah-Hartman 已提交
139
		bus_put(bus);
L
Linus Torvalds 已提交
140 141
	}
}
142
EXPORT_SYMBOL_GPL(bus_remove_file);
L
Linus Torvalds 已提交
143

144
static struct kobj_type bus_ktype = {
L
Linus Torvalds 已提交
145
	.sysfs_ops	= &bus_sysfs_ops,
146 147 148 149 150 151 152 153 154 155
};

static int bus_uevent_filter(struct kset *kset, struct kobject *kobj)
{
	struct kobj_type *ktype = get_ktype(kobj);

	if (ktype == &bus_ktype)
		return 1;
	return 0;
}
L
Linus Torvalds 已提交
156

157 158
static struct kset_uevent_ops bus_uevent_ops = {
	.filter = bus_uevent_filter,
L
Linus Torvalds 已提交
159 160
};

161
static struct kset *bus_kset;
L
Linus Torvalds 已提交
162 163


164
#ifdef CONFIG_HOTPLUG
A
Alan Stern 已提交
165
/* Manually detach a device from its associated driver. */
166 167 168
static ssize_t driver_unbind(struct device_driver *drv,
			     const char *buf, size_t count)
{
G
Greg Kroah-Hartman 已提交
169
	struct bus_type *bus = bus_get(drv->bus);
170 171 172
	struct device *dev;
	int err = -ENODEV;

173
	dev = bus_find_device_by_name(bus, NULL, buf);
A
Alan Stern 已提交
174
	if (dev && dev->driver == drv) {
175 176
		if (dev->parent)	/* Needed for USB */
			down(&dev->parent->sem);
177
		device_release_driver(dev);
178 179
		if (dev->parent)
			up(&dev->parent->sem);
180 181
		err = count;
	}
A
Alan Stern 已提交
182
	put_device(dev);
G
Greg Kroah-Hartman 已提交
183
	bus_put(bus);
A
Alan Stern 已提交
184
	return err;
185 186 187
}
static DRIVER_ATTR(unbind, S_IWUSR, NULL, driver_unbind);

188 189 190 191 192 193 194 195
/*
 * 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)
{
G
Greg Kroah-Hartman 已提交
196
	struct bus_type *bus = bus_get(drv->bus);
197 198 199
	struct device *dev;
	int err = -ENODEV;

200
	dev = bus_find_device_by_name(bus, NULL, buf);
A
Alan Stern 已提交
201
	if (dev && dev->driver == NULL) {
202 203
		if (dev->parent)	/* Needed for USB */
			down(&dev->parent->sem);
204 205 206
		down(&dev->sem);
		err = driver_probe_device(drv, dev);
		up(&dev->sem);
207 208
		if (dev->parent)
			up(&dev->parent->sem);
209

210 211
		if (err > 0) {
			/* success */
212
			err = count;
213 214
		} else if (err == 0) {
			/* driver didn't accept device */
215
			err = -ENODEV;
216
		}
217
	}
A
Alan Stern 已提交
218
	put_device(dev);
G
Greg Kroah-Hartman 已提交
219
	bus_put(bus);
A
Alan Stern 已提交
220
	return err;
221 222 223
}
static DRIVER_ATTR(bind, S_IWUSR, NULL, driver_bind);

224 225
static ssize_t show_drivers_autoprobe(struct bus_type *bus, char *buf)
{
226
	return sprintf(buf, "%d\n", bus->p->drivers_autoprobe);
227 228 229 230 231 232
}

static ssize_t store_drivers_autoprobe(struct bus_type *bus,
				       const char *buf, size_t count)
{
	if (buf[0] == '0')
233
		bus->p->drivers_autoprobe = 0;
234
	else
235
		bus->p->drivers_autoprobe = 1;
236 237 238 239 240 241 242 243
	return count;
}

static ssize_t store_drivers_probe(struct bus_type *bus,
				   const char *buf, size_t count)
{
	struct device *dev;

244
	dev = bus_find_device_by_name(bus, NULL, buf);
245 246 247 248 249 250
	if (!dev)
		return -ENODEV;
	if (bus_rescan_devices_helper(dev, NULL) != 0)
		return -EINVAL;
	return count;
}
251
#endif
252

253
static struct device *next_device(struct klist_iter *i)
254
{
255
	struct klist_node *n = klist_next(i);
256 257 258
	return n ? container_of(n, struct device, knode_bus) : NULL;
}

L
Linus Torvalds 已提交
259
/**
260 261 262 263 264
 * 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.
L
Linus Torvalds 已提交
265
 *
266 267 268
 * 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.
L
Linus Torvalds 已提交
269
 *
270 271
 * We check the return of @fn each time. If it returns anything
 * other than 0, we break out and return that value.
L
Linus Torvalds 已提交
272
 *
273 274 275 276
 * 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.
L
Linus Torvalds 已提交
277
 */
278 279
int bus_for_each_dev(struct bus_type *bus, struct device *start,
		     void *data, int (*fn)(struct device *, void *))
L
Linus Torvalds 已提交
280
{
281
	struct klist_iter i;
282
	struct device *dev;
283
	int error = 0;
L
Linus Torvalds 已提交
284

285 286 287
	if (!bus)
		return -EINVAL;

288
	klist_iter_init_node(&bus->p->klist_devices, &i,
289 290 291 292 293
			     (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
294
}
295
EXPORT_SYMBOL_GPL(bus_for_each_dev);
L
Linus Torvalds 已提交
296

297 298 299 300 301 302 303 304 305 306 307 308 309 310 311
/**
 * 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.
 */
312 313 314
struct device *bus_find_device(struct bus_type *bus,
			       struct device *start, void *data,
			       int (*match)(struct device *dev, void *data))
315 316 317 318 319 320 321
{
	struct klist_iter i;
	struct device *dev;

	if (!bus)
		return NULL;

322
	klist_iter_init_node(&bus->p->klist_devices, &i,
323 324 325 326 327 328 329
			     (start ? &start->knode_bus : NULL));
	while ((dev = next_device(&i)))
		if (match(dev, data) && get_device(dev))
			break;
	klist_iter_exit(&i);
	return dev;
}
330
EXPORT_SYMBOL_GPL(bus_find_device);
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
static int match_name(struct device *dev, void *data)
{
	const char *name = data;

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

/**
 * bus_find_device_by_name - device iterator for locating a particular device of a specific name
 * @bus: bus type
 * @start: Device to begin with
 * @name: name of the device to match
 *
 * This is similar to the bus_find_device() function above, but it handles
 * searching by a name automatically, no need to write another strcmp matching
 * function.
 */
struct device *bus_find_device_by_name(struct bus_type *bus,
				       struct device *start, const char *name)
{
	return bus_find_device(bus, start, (void *)name, match_name);
}
EXPORT_SYMBOL_GPL(bus_find_device_by_name);

358
static struct device_driver *next_driver(struct klist_iter *i)
359
{
360
	struct klist_node *n = klist_next(i);
361 362 363 364 365 366 367
	struct driver_private *drv_priv;

	if (n) {
		drv_priv = container_of(n, struct driver_private, knode_bus);
		return drv_priv->driver;
	}
	return NULL;
368 369
}

L
Linus Torvalds 已提交
370
/**
371 372 373 374 375
 * 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.
L
Linus Torvalds 已提交
376
 *
377 378 379 380 381
 * 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.
L
Linus Torvalds 已提交
382
 *
383 384 385 386 387
 * 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.
L
Linus Torvalds 已提交
388
 */
389 390
int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
		     void *data, int (*fn)(struct device_driver *, void *))
L
Linus Torvalds 已提交
391
{
392
	struct klist_iter i;
393
	struct device_driver *drv;
394
	int error = 0;
L
Linus Torvalds 已提交
395

396 397 398
	if (!bus)
		return -EINVAL;

399
	klist_iter_init_node(&bus->p->klist_drivers, &i,
400
			     start ? &start->p->knode_bus : NULL);
401 402 403 404
	while ((drv = next_driver(&i)) && !error)
		error = fn(drv, data);
	klist_iter_exit(&i);
	return error;
L
Linus Torvalds 已提交
405
}
406
EXPORT_SYMBOL_GPL(bus_for_each_drv);
L
Linus Torvalds 已提交
407

408
static int device_add_attrs(struct bus_type *bus, struct device *dev)
L
Linus Torvalds 已提交
409 410 411 412
{
	int error = 0;
	int i;

413 414 415 416
	if (!bus->dev_attrs)
		return 0;

	for (i = 0; attr_name(bus->dev_attrs[i]); i++) {
417
		error = device_create_file(dev, &bus->dev_attrs[i]);
418 419 420 421
		if (error) {
			while (--i >= 0)
				device_remove_file(dev, &bus->dev_attrs[i]);
			break;
L
Linus Torvalds 已提交
422 423 424 425 426
		}
	}
	return error;
}

427
static void device_remove_attrs(struct bus_type *bus, struct device *dev)
L
Linus Torvalds 已提交
428 429 430 431 432
{
	int i;

	if (bus->dev_attrs) {
		for (i = 0; attr_name(bus->dev_attrs[i]); i++)
433
			device_remove_file(dev, &bus->dev_attrs[i]);
L
Linus Torvalds 已提交
434 435 436
	}
}

437 438 439 440
#ifdef CONFIG_SYSFS_DEPRECATED
static int make_deprecated_bus_links(struct device *dev)
{
	return sysfs_create_link(&dev->kobj,
441
				 &dev->bus->p->subsys.kobj, "bus");
442 443 444 445 446 447 448 449 450 451
}

static void remove_deprecated_bus_links(struct device *dev)
{
	sysfs_remove_link(&dev->kobj, "bus");
}
#else
static inline int make_deprecated_bus_links(struct device *dev) { return 0; }
static inline void remove_deprecated_bus_links(struct device *dev) { }
#endif
L
Linus Torvalds 已提交
452 453

/**
454 455
 * bus_add_device - add device to bus
 * @dev: device being added
L
Linus Torvalds 已提交
456
 *
457 458
 * - Add the device to its bus's list of devices.
 * - Create link to device's bus.
L
Linus Torvalds 已提交
459
 */
460
int bus_add_device(struct device *dev)
L
Linus Torvalds 已提交
461
{
462
	struct bus_type *bus = bus_get(dev->bus);
L
Linus Torvalds 已提交
463 464 465
	int error = 0;

	if (bus) {
466
		pr_debug("bus: '%s': add device %s\n", bus->name, dev->bus_id);
467
		error = device_add_attrs(bus, dev);
A
Andrew Morton 已提交
468
		if (error)
469
			goto out_put;
470
		error = sysfs_create_link(&bus->p->devices_kset->kobj,
A
Andrew Morton 已提交
471 472
						&dev->kobj, dev->bus_id);
		if (error)
473
			goto out_id;
A
Andrew Morton 已提交
474
		error = sysfs_create_link(&dev->kobj,
475
				&dev->bus->p->subsys.kobj, "subsystem");
A
Andrew Morton 已提交
476
		if (error)
477
			goto out_subsys;
478
		error = make_deprecated_bus_links(dev);
479 480
		if (error)
			goto out_deprecated;
L
Linus Torvalds 已提交
481
	}
482 483 484 485 486
	return 0;

out_deprecated:
	sysfs_remove_link(&dev->kobj, "subsystem");
out_subsys:
487
	sysfs_remove_link(&bus->p->devices_kset->kobj, dev->bus_id);
488 489 490
out_id:
	device_remove_attrs(bus, dev);
out_put:
G
Greg Kroah-Hartman 已提交
491
	bus_put(dev->bus);
L
Linus Torvalds 已提交
492 493 494
	return error;
}

495
/**
496 497
 * bus_attach_device - add device to bus
 * @dev: device tried to attach to a driver
498
 *
499 500
 * - Add device to bus's list of devices.
 * - Try to attach to driver.
501
 */
502
void bus_attach_device(struct device *dev)
503
{
A
Andrew Morton 已提交
504 505
	struct bus_type *bus = dev->bus;
	int ret = 0;
506 507

	if (bus) {
508
		dev->is_registered = 1;
509
		if (bus->p->drivers_autoprobe)
510
			ret = device_attach(dev);
511 512
		WARN_ON(ret < 0);
		if (ret >= 0)
513
			klist_add_tail(&dev->knode_bus, &bus->p->klist_devices);
514
		else
515
			dev->is_registered = 0;
516 517 518
	}
}

L
Linus Torvalds 已提交
519
/**
520 521
 * bus_remove_device - remove device from bus
 * @dev: device to be removed
L
Linus Torvalds 已提交
522
 *
523 524 525 526
 * - Remove symlink from bus's directory.
 * - Delete device from bus's list.
 * - Detach from its driver.
 * - Drop reference taken in bus_add_device().
L
Linus Torvalds 已提交
527
 */
528
void bus_remove_device(struct device *dev)
L
Linus Torvalds 已提交
529 530
{
	if (dev->bus) {
531
		sysfs_remove_link(&dev->kobj, "subsystem");
532
		remove_deprecated_bus_links(dev);
533 534
		sysfs_remove_link(&dev->bus->p->devices_kset->kobj,
				  dev->bus_id);
L
Linus Torvalds 已提交
535
		device_remove_attrs(dev->bus, dev);
536 537 538 539
		if (dev->is_registered) {
			dev->is_registered = 0;
			klist_del(&dev->knode_bus);
		}
540 541
		pr_debug("bus: '%s': remove device %s\n",
			 dev->bus->name, dev->bus_id);
L
Linus Torvalds 已提交
542
		device_release_driver(dev);
G
Greg Kroah-Hartman 已提交
543
		bus_put(dev->bus);
L
Linus Torvalds 已提交
544 545 546
	}
}

547
static int driver_add_attrs(struct bus_type *bus, struct device_driver *drv)
L
Linus Torvalds 已提交
548 549 550 551 552 553 554 555
{
	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)
556
				goto err;
L
Linus Torvalds 已提交
557 558
		}
	}
559
done:
L
Linus Torvalds 已提交
560
	return error;
561
err:
L
Linus Torvalds 已提交
562 563
	while (--i >= 0)
		driver_remove_file(drv, &bus->drv_attrs[i]);
564
	goto done;
L
Linus Torvalds 已提交
565 566
}

567 568
static void driver_remove_attrs(struct bus_type *bus,
				struct device_driver *drv)
L
Linus Torvalds 已提交
569 570 571 572 573 574 575 576 577
{
	int i;

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

578 579 580 581 582
#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
583
static int __must_check add_bind_files(struct device_driver *drv)
584
{
A
Andrew Morton 已提交
585 586 587 588 589 590 591 592 593
	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;
594 595 596 597 598 599 600
}

static void remove_bind_files(struct device_driver *drv)
{
	driver_remove_file(drv, &driver_attr_bind);
	driver_remove_file(drv, &driver_attr_unbind);
}
601

602 603 604 605
static BUS_ATTR(drivers_probe, S_IWUSR, NULL, store_drivers_probe);
static BUS_ATTR(drivers_autoprobe, S_IWUSR | S_IRUGO,
		show_drivers_autoprobe, store_drivers_autoprobe);

606 607 608 609
static int add_probe_files(struct bus_type *bus)
{
	int retval;

610
	retval = bus_create_file(bus, &bus_attr_drivers_probe);
611 612 613
	if (retval)
		goto out;

614
	retval = bus_create_file(bus, &bus_attr_drivers_autoprobe);
615
	if (retval)
616
		bus_remove_file(bus, &bus_attr_drivers_probe);
617 618 619 620 621 622
out:
	return retval;
}

static void remove_probe_files(struct bus_type *bus)
{
623 624
	bus_remove_file(bus, &bus_attr_drivers_autoprobe);
	bus_remove_file(bus, &bus_attr_drivers_probe);
625
}
626
#else
627
static inline int add_bind_files(struct device_driver *drv) { return 0; }
628
static inline void remove_bind_files(struct device_driver *drv) {}
629 630
static inline int add_probe_files(struct bus_type *bus) { return 0; }
static inline void remove_probe_files(struct bus_type *bus) {}
631
#endif
L
Linus Torvalds 已提交
632

633 634 635 636 637 638
static ssize_t driver_uevent_store(struct device_driver *drv,
				   const char *buf, size_t count)
{
	enum kobject_action action;

	if (kobject_action_type(buf, count, &action) == 0)
639
		kobject_uevent(&drv->p->kobj, action);
640 641 642 643
	return count;
}
static DRIVER_ATTR(uevent, S_IWUSR, NULL, driver_uevent_store);

L
Linus Torvalds 已提交
644
/**
645 646
 * bus_add_driver - Add a driver to the bus.
 * @drv: driver.
L
Linus Torvalds 已提交
647
 */
A
Andrew Morton 已提交
648
int bus_add_driver(struct device_driver *drv)
L
Linus Torvalds 已提交
649
{
650 651
	struct bus_type *bus;
	struct driver_private *priv;
L
Linus Torvalds 已提交
652 653
	int error = 0;

654
	bus = bus_get(drv->bus);
655
	if (!bus)
656
		return -EINVAL;
657

658
	pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name);
659 660

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
661 662 663 664
	if (!priv) {
		error = -ENOMEM;
		goto out_put_bus;
	}
665 666 667
	klist_init(&priv->klist_devices, NULL, NULL);
	priv->driver = drv;
	drv->p = priv;
668 669 670
	priv->kobj.kset = bus->p->drivers_kset;
	error = kobject_init_and_add(&priv->kobj, &driver_ktype, NULL,
				     "%s", drv->name);
671
	if (error)
672
		goto out_unregister;
673

674
	if (drv->bus->p->drivers_autoprobe) {
675 676 677 678
		error = driver_attach(drv);
		if (error)
			goto out_unregister;
	}
679
	klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers);
680 681
	module_add_driver(drv->owner, drv);

682 683 684 685 686
	error = driver_create_file(drv, &driver_attr_uevent);
	if (error) {
		printk(KERN_ERR "%s: uevent attr (%s) failed\n",
			__FUNCTION__, drv->name);
	}
687 688 689 690 691 692 693 694 695 696 697
	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
698
	}
699

700
	kobject_uevent(&priv->kobj, KOBJ_ADD);
L
Linus Torvalds 已提交
701
	return error;
A
Andrew Morton 已提交
702
out_unregister:
703
	kobject_put(&priv->kobj);
A
Andrew Morton 已提交
704
out_put_bus:
G
Greg Kroah-Hartman 已提交
705
	bus_put(bus);
A
Andrew Morton 已提交
706
	return error;
L
Linus Torvalds 已提交
707 708 709
}

/**
710 711
 * bus_remove_driver - delete driver from bus's knowledge.
 * @drv: driver.
L
Linus Torvalds 已提交
712
 *
713 714 715
 * 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().
L
Linus Torvalds 已提交
716
 */
717
void bus_remove_driver(struct device_driver *drv)
L
Linus Torvalds 已提交
718
{
719 720 721 722 723
	if (!drv->bus)
		return;

	remove_bind_files(drv);
	driver_remove_attrs(drv->bus, drv);
724
	driver_remove_file(drv, &driver_attr_uevent);
725
	klist_remove(&drv->p->knode_bus);
726
	pr_debug("bus: '%s': remove driver %s\n", drv->bus->name, drv->name);
727 728
	driver_detach(drv);
	module_remove_driver(drv);
729
	kobject_put(&drv->p->kobj);
G
Greg Kroah-Hartman 已提交
730
	bus_put(drv->bus);
L
Linus Torvalds 已提交
731 732 733
}

/* Helper for bus_rescan_devices's iter */
A
Andrew Morton 已提交
734
static int __must_check bus_rescan_devices_helper(struct device *dev,
735
						  void *data)
L
Linus Torvalds 已提交
736
{
A
Andrew Morton 已提交
737 738
	int ret = 0;

739 740 741
	if (!dev->driver) {
		if (dev->parent)	/* Needed for USB */
			down(&dev->parent->sem);
A
Andrew Morton 已提交
742
		ret = device_attach(dev);
743 744 745
		if (dev->parent)
			up(&dev->parent->sem);
	}
A
Andrew Morton 已提交
746
	return ret < 0 ? ret : 0;
L
Linus Torvalds 已提交
747 748 749
}

/**
750 751
 * bus_rescan_devices - rescan devices on the bus for possible drivers
 * @bus: the bus to scan.
L
Linus Torvalds 已提交
752
 *
753 754 755
 * 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
756
 */
757
int bus_rescan_devices(struct bus_type *bus)
L
Linus Torvalds 已提交
758
{
A
Andrew Morton 已提交
759
	return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
L
Linus Torvalds 已提交
760
}
761
EXPORT_SYMBOL_GPL(bus_rescan_devices);
L
Linus Torvalds 已提交
762

763 764 765 766 767 768 769 770 771
/**
 * 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
772
int device_reprobe(struct device *dev)
773 774 775 776 777 778 779 780
{
	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
781
	return bus_rescan_devices_helper(dev, NULL);
782 783
}
EXPORT_SYMBOL_GPL(device_reprobe);
L
Linus Torvalds 已提交
784 785

/**
786 787
 * find_bus - locate bus by name.
 * @name: name of bus.
L
Linus Torvalds 已提交
788
 *
789 790
 * Call kset_find_obj() to iterate over list of buses to
 * find a bus by name. Return bus if found.
L
Linus Torvalds 已提交
791
 *
792
 * Note that kset_find_obj increments bus' reference count.
L
Linus Torvalds 已提交
793
 */
794
#if 0
795
struct bus_type *find_bus(char *name)
L
Linus Torvalds 已提交
796
{
797
	struct kobject *k = kset_find_obj(bus_kset, name);
L
Linus Torvalds 已提交
798 799
	return k ? to_bus(k) : NULL;
}
800
#endif  /*  0  */
L
Linus Torvalds 已提交
801 802 803


/**
804 805
 * bus_add_attrs - Add default attributes for this bus.
 * @bus: Bus that has just been registered.
L
Linus Torvalds 已提交
806 807
 */

808
static int bus_add_attrs(struct bus_type *bus)
L
Linus Torvalds 已提交
809 810 811 812 813 814
{
	int error = 0;
	int i;

	if (bus->bus_attrs) {
		for (i = 0; attr_name(bus->bus_attrs[i]); i++) {
815
			error = bus_create_file(bus, &bus->bus_attrs[i]);
816
			if (error)
817
				goto err;
L
Linus Torvalds 已提交
818 819
		}
	}
820
done:
L
Linus Torvalds 已提交
821
	return error;
822
err:
L
Linus Torvalds 已提交
823
	while (--i >= 0)
824 825
		bus_remove_file(bus, &bus->bus_attrs[i]);
	goto done;
L
Linus Torvalds 已提交
826 827
}

828
static void bus_remove_attrs(struct bus_type *bus)
L
Linus Torvalds 已提交
829 830 831 832 833
{
	int i;

	if (bus->bus_attrs) {
		for (i = 0; attr_name(bus->bus_attrs[i]); i++)
834
			bus_remove_file(bus, &bus->bus_attrs[i]);
L
Linus Torvalds 已提交
835 836 837
	}
}

838 839 840 841 842 843 844 845 846 847 848 849 850 851
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);
}

852 853 854 855 856 857
static ssize_t bus_uevent_store(struct bus_type *bus,
				const char *buf, size_t count)
{
	enum kobject_action action;

	if (kobject_action_type(buf, count, &action) == 0)
858
		kobject_uevent(&bus->p->subsys.kobj, action);
859 860 861 862
	return count;
}
static BUS_ATTR(uevent, S_IWUSR, NULL, bus_uevent_store);

L
Linus Torvalds 已提交
863
/**
864 865
 * bus_register - register a bus with the system.
 * @bus: bus.
L
Linus Torvalds 已提交
866
 *
867 868 869
 * 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.
L
Linus Torvalds 已提交
870
 */
871
int bus_register(struct bus_type *bus)
L
Linus Torvalds 已提交
872 873
{
	int retval;
874 875 876 877 878 879 880 881
	struct bus_type_private *priv;

	priv = kzalloc(sizeof(struct bus_type_private), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->bus = bus;
	bus->p = priv;
L
Linus Torvalds 已提交
882

883
	BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier);
884

885
	retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name);
L
Linus Torvalds 已提交
886 887 888
	if (retval)
		goto out;

889 890 891
	priv->subsys.kobj.kset = bus_kset;
	priv->subsys.kobj.ktype = &bus_ktype;
	priv->drivers_autoprobe = 1;
892

893
	retval = kset_register(&priv->subsys);
L
Linus Torvalds 已提交
894 895 896
	if (retval)
		goto out;

897 898 899 900
	retval = bus_create_file(bus, &bus_attr_uevent);
	if (retval)
		goto bus_uevent_fail;

901 902 903
	priv->devices_kset = kset_create_and_add("devices", NULL,
						 &priv->subsys.kobj);
	if (!priv->devices_kset) {
904
		retval = -ENOMEM;
L
Linus Torvalds 已提交
905
		goto bus_devices_fail;
906
	}
L
Linus Torvalds 已提交
907

908 909 910
	priv->drivers_kset = kset_create_and_add("drivers", NULL,
						 &priv->subsys.kobj);
	if (!priv->drivers_kset) {
911
		retval = -ENOMEM;
L
Linus Torvalds 已提交
912
		goto bus_drivers_fail;
913
	}
914

915 916
	klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put);
	klist_init(&priv->klist_drivers, NULL, NULL);
917 918 919 920 921

	retval = add_probe_files(bus);
	if (retval)
		goto bus_probe_files_fail;

922 923 924
	retval = bus_add_attrs(bus);
	if (retval)
		goto bus_attrs_fail;
L
Linus Torvalds 已提交
925

926
	pr_debug("bus: '%s': registered\n", bus->name);
L
Linus Torvalds 已提交
927 928
	return 0;

929
bus_attrs_fail:
930 931
	remove_probe_files(bus);
bus_probe_files_fail:
932
	kset_unregister(bus->p->drivers_kset);
L
Linus Torvalds 已提交
933
bus_drivers_fail:
934
	kset_unregister(bus->p->devices_kset);
L
Linus Torvalds 已提交
935
bus_devices_fail:
936 937
	bus_remove_file(bus, &bus_attr_uevent);
bus_uevent_fail:
938 939
	kset_unregister(&bus->p->subsys);
	kfree(bus->p);
L
Linus Torvalds 已提交
940 941 942
out:
	return retval;
}
943
EXPORT_SYMBOL_GPL(bus_register);
L
Linus Torvalds 已提交
944 945

/**
946 947
 * bus_unregister - remove a bus from the system
 * @bus: bus.
L
Linus Torvalds 已提交
948
 *
949 950
 * Unregister the child subsystems and the bus itself.
 * Finally, we call bus_put() to release the refcount
L
Linus Torvalds 已提交
951
 */
952
void bus_unregister(struct bus_type *bus)
L
Linus Torvalds 已提交
953
{
954
	pr_debug("bus: '%s': unregistering\n", bus->name);
L
Linus Torvalds 已提交
955
	bus_remove_attrs(bus);
956
	remove_probe_files(bus);
957 958
	kset_unregister(bus->p->drivers_kset);
	kset_unregister(bus->p->devices_kset);
959
	bus_remove_file(bus, &bus_attr_uevent);
960 961
	kset_unregister(&bus->p->subsys);
	kfree(bus->p);
L
Linus Torvalds 已提交
962
}
963
EXPORT_SYMBOL_GPL(bus_unregister);
L
Linus Torvalds 已提交
964

965 966
int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
{
967
	return blocking_notifier_chain_register(&bus->p->bus_notifier, nb);
968 969 970 971 972
}
EXPORT_SYMBOL_GPL(bus_register_notifier);

int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
{
973
	return blocking_notifier_chain_unregister(&bus->p->bus_notifier, nb);
974 975 976
}
EXPORT_SYMBOL_GPL(bus_unregister_notifier);

977 978
struct kset *bus_get_kset(struct bus_type *bus)
{
979
	return &bus->p->subsys;
980 981 982
}
EXPORT_SYMBOL_GPL(bus_get_kset);

983 984
struct klist *bus_get_device_klist(struct bus_type *bus)
{
985
	return &bus->p->klist_devices;
986 987 988
}
EXPORT_SYMBOL_GPL(bus_get_device_klist);

L
Linus Torvalds 已提交
989 990
int __init buses_init(void)
{
991 992 993 994
	bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);
	if (!bus_kset)
		return -ENOMEM;
	return 0;
L
Linus Torvalds 已提交
995
}