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v3.15
 
   1/*
   2 * drivers/base/core.c - core driver model code (device registration, etc)
   3 *
   4 * Copyright (c) 2002-3 Patrick Mochel
   5 * Copyright (c) 2002-3 Open Source Development Labs
   6 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
   7 * Copyright (c) 2006 Novell, Inc.
   8 *
   9 * This file is released under the GPLv2
  10 *
  11 */
  12
  13#include <linux/device.h>
  14#include <linux/err.h>
 
  15#include <linux/init.h>
  16#include <linux/module.h>
  17#include <linux/slab.h>
  18#include <linux/string.h>
  19#include <linux/kdev_t.h>
  20#include <linux/notifier.h>
  21#include <linux/of.h>
  22#include <linux/of_device.h>
  23#include <linux/genhd.h>
  24#include <linux/kallsyms.h>
  25#include <linux/mutex.h>
  26#include <linux/pm_runtime.h>
  27#include <linux/netdevice.h>
 
  28#include <linux/sysfs.h>
  29
  30#include "base.h"
  31#include "power/power.h"
  32
  33#ifdef CONFIG_SYSFS_DEPRECATED
  34#ifdef CONFIG_SYSFS_DEPRECATED_V2
  35long sysfs_deprecated = 1;
  36#else
  37long sysfs_deprecated = 0;
  38#endif
  39static int __init sysfs_deprecated_setup(char *arg)
  40{
  41	return kstrtol(arg, 10, &sysfs_deprecated);
  42}
  43early_param("sysfs.deprecated", sysfs_deprecated_setup);
  44#endif
  45
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  46int (*platform_notify)(struct device *dev) = NULL;
  47int (*platform_notify_remove)(struct device *dev) = NULL;
  48static struct kobject *dev_kobj;
  49struct kobject *sysfs_dev_char_kobj;
  50struct kobject *sysfs_dev_block_kobj;
  51
  52static DEFINE_MUTEX(device_hotplug_lock);
  53
  54void lock_device_hotplug(void)
  55{
  56	mutex_lock(&device_hotplug_lock);
  57}
  58
  59void unlock_device_hotplug(void)
  60{
  61	mutex_unlock(&device_hotplug_lock);
  62}
  63
  64int lock_device_hotplug_sysfs(void)
  65{
  66	if (mutex_trylock(&device_hotplug_lock))
  67		return 0;
  68
  69	/* Avoid busy looping (5 ms of sleep should do). */
  70	msleep(5);
  71	return restart_syscall();
  72}
  73
  74#ifdef CONFIG_BLOCK
  75static inline int device_is_not_partition(struct device *dev)
  76{
  77	return !(dev->type == &part_type);
  78}
  79#else
  80static inline int device_is_not_partition(struct device *dev)
  81{
  82	return 1;
  83}
  84#endif
  85
  86/**
  87 * dev_driver_string - Return a device's driver name, if at all possible
  88 * @dev: struct device to get the name of
  89 *
  90 * Will return the device's driver's name if it is bound to a device.  If
  91 * the device is not bound to a driver, it will return the name of the bus
  92 * it is attached to.  If it is not attached to a bus either, an empty
  93 * string will be returned.
  94 */
  95const char *dev_driver_string(const struct device *dev)
  96{
  97	struct device_driver *drv;
  98
  99	/* dev->driver can change to NULL underneath us because of unbinding,
 100	 * so be careful about accessing it.  dev->bus and dev->class should
 101	 * never change once they are set, so they don't need special care.
 102	 */
 103	drv = ACCESS_ONCE(dev->driver);
 104	return drv ? drv->name :
 105			(dev->bus ? dev->bus->name :
 106			(dev->class ? dev->class->name : ""));
 107}
 108EXPORT_SYMBOL(dev_driver_string);
 109
 110#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
 111
 112static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
 113			     char *buf)
 114{
 115	struct device_attribute *dev_attr = to_dev_attr(attr);
 116	struct device *dev = kobj_to_dev(kobj);
 117	ssize_t ret = -EIO;
 118
 119	if (dev_attr->show)
 120		ret = dev_attr->show(dev, dev_attr, buf);
 121	if (ret >= (ssize_t)PAGE_SIZE) {
 122		print_symbol("dev_attr_show: %s returned bad count\n",
 123				(unsigned long)dev_attr->show);
 124	}
 125	return ret;
 126}
 127
 128static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
 129			      const char *buf, size_t count)
 130{
 131	struct device_attribute *dev_attr = to_dev_attr(attr);
 132	struct device *dev = kobj_to_dev(kobj);
 133	ssize_t ret = -EIO;
 134
 135	if (dev_attr->store)
 136		ret = dev_attr->store(dev, dev_attr, buf, count);
 137	return ret;
 138}
 139
 140static const struct sysfs_ops dev_sysfs_ops = {
 141	.show	= dev_attr_show,
 142	.store	= dev_attr_store,
 143};
 144
 145#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
 146
 147ssize_t device_store_ulong(struct device *dev,
 148			   struct device_attribute *attr,
 149			   const char *buf, size_t size)
 150{
 151	struct dev_ext_attribute *ea = to_ext_attr(attr);
 152	char *end;
 153	unsigned long new = simple_strtoul(buf, &end, 0);
 154	if (end == buf)
 155		return -EINVAL;
 156	*(unsigned long *)(ea->var) = new;
 157	/* Always return full write size even if we didn't consume all */
 158	return size;
 159}
 160EXPORT_SYMBOL_GPL(device_store_ulong);
 161
 162ssize_t device_show_ulong(struct device *dev,
 163			  struct device_attribute *attr,
 164			  char *buf)
 165{
 166	struct dev_ext_attribute *ea = to_ext_attr(attr);
 167	return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
 168}
 169EXPORT_SYMBOL_GPL(device_show_ulong);
 170
 171ssize_t device_store_int(struct device *dev,
 172			 struct device_attribute *attr,
 173			 const char *buf, size_t size)
 174{
 175	struct dev_ext_attribute *ea = to_ext_attr(attr);
 176	char *end;
 177	long new = simple_strtol(buf, &end, 0);
 178	if (end == buf || new > INT_MAX || new < INT_MIN)
 179		return -EINVAL;
 180	*(int *)(ea->var) = new;
 181	/* Always return full write size even if we didn't consume all */
 182	return size;
 183}
 184EXPORT_SYMBOL_GPL(device_store_int);
 185
 186ssize_t device_show_int(struct device *dev,
 187			struct device_attribute *attr,
 188			char *buf)
 189{
 190	struct dev_ext_attribute *ea = to_ext_attr(attr);
 191
 192	return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
 193}
 194EXPORT_SYMBOL_GPL(device_show_int);
 195
 196ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
 197			  const char *buf, size_t size)
 198{
 199	struct dev_ext_attribute *ea = to_ext_attr(attr);
 200
 201	if (strtobool(buf, ea->var) < 0)
 202		return -EINVAL;
 203
 204	return size;
 205}
 206EXPORT_SYMBOL_GPL(device_store_bool);
 207
 208ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
 209			 char *buf)
 210{
 211	struct dev_ext_attribute *ea = to_ext_attr(attr);
 212
 213	return snprintf(buf, PAGE_SIZE, "%d\n", *(bool *)(ea->var));
 214}
 215EXPORT_SYMBOL_GPL(device_show_bool);
 216
 217/**
 218 * device_release - free device structure.
 219 * @kobj: device's kobject.
 220 *
 221 * This is called once the reference count for the object
 222 * reaches 0. We forward the call to the device's release
 223 * method, which should handle actually freeing the structure.
 224 */
 225static void device_release(struct kobject *kobj)
 226{
 227	struct device *dev = kobj_to_dev(kobj);
 228	struct device_private *p = dev->p;
 229
 230	/*
 231	 * Some platform devices are driven without driver attached
 232	 * and managed resources may have been acquired.  Make sure
 233	 * all resources are released.
 234	 *
 235	 * Drivers still can add resources into device after device
 236	 * is deleted but alive, so release devres here to avoid
 237	 * possible memory leak.
 238	 */
 239	devres_release_all(dev);
 240
 241	if (dev->release)
 242		dev->release(dev);
 243	else if (dev->type && dev->type->release)
 244		dev->type->release(dev);
 245	else if (dev->class && dev->class->dev_release)
 246		dev->class->dev_release(dev);
 247	else
 248		WARN(1, KERN_ERR "Device '%s' does not have a release() "
 249			"function, it is broken and must be fixed.\n",
 250			dev_name(dev));
 251	kfree(p);
 252}
 253
 254static const void *device_namespace(struct kobject *kobj)
 255{
 256	struct device *dev = kobj_to_dev(kobj);
 257	const void *ns = NULL;
 258
 259	if (dev->class && dev->class->ns_type)
 260		ns = dev->class->namespace(dev);
 261
 262	return ns;
 263}
 264
 265static struct kobj_type device_ktype = {
 266	.release	= device_release,
 267	.sysfs_ops	= &dev_sysfs_ops,
 268	.namespace	= device_namespace,
 269};
 270
 271
 272static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
 273{
 274	struct kobj_type *ktype = get_ktype(kobj);
 275
 276	if (ktype == &device_ktype) {
 277		struct device *dev = kobj_to_dev(kobj);
 278		if (dev->bus)
 279			return 1;
 280		if (dev->class)
 281			return 1;
 282	}
 283	return 0;
 284}
 285
 286static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
 287{
 288	struct device *dev = kobj_to_dev(kobj);
 289
 290	if (dev->bus)
 291		return dev->bus->name;
 292	if (dev->class)
 293		return dev->class->name;
 294	return NULL;
 295}
 296
 297static int dev_uevent(struct kset *kset, struct kobject *kobj,
 298		      struct kobj_uevent_env *env)
 299{
 300	struct device *dev = kobj_to_dev(kobj);
 301	int retval = 0;
 302
 303	/* add device node properties if present */
 304	if (MAJOR(dev->devt)) {
 305		const char *tmp;
 306		const char *name;
 307		umode_t mode = 0;
 308		kuid_t uid = GLOBAL_ROOT_UID;
 309		kgid_t gid = GLOBAL_ROOT_GID;
 310
 311		add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
 312		add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
 313		name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
 314		if (name) {
 315			add_uevent_var(env, "DEVNAME=%s", name);
 316			if (mode)
 317				add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
 318			if (!uid_eq(uid, GLOBAL_ROOT_UID))
 319				add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
 320			if (!gid_eq(gid, GLOBAL_ROOT_GID))
 321				add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
 322			kfree(tmp);
 323		}
 324	}
 325
 326	if (dev->type && dev->type->name)
 327		add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
 328
 329	if (dev->driver)
 330		add_uevent_var(env, "DRIVER=%s", dev->driver->name);
 331
 332	/* Add common DT information about the device */
 333	of_device_uevent(dev, env);
 334
 335	/* have the bus specific function add its stuff */
 336	if (dev->bus && dev->bus->uevent) {
 337		retval = dev->bus->uevent(dev, env);
 338		if (retval)
 339			pr_debug("device: '%s': %s: bus uevent() returned %d\n",
 340				 dev_name(dev), __func__, retval);
 341	}
 342
 343	/* have the class specific function add its stuff */
 344	if (dev->class && dev->class->dev_uevent) {
 345		retval = dev->class->dev_uevent(dev, env);
 346		if (retval)
 347			pr_debug("device: '%s': %s: class uevent() "
 348				 "returned %d\n", dev_name(dev),
 349				 __func__, retval);
 350	}
 351
 352	/* have the device type specific function add its stuff */
 353	if (dev->type && dev->type->uevent) {
 354		retval = dev->type->uevent(dev, env);
 355		if (retval)
 356			pr_debug("device: '%s': %s: dev_type uevent() "
 357				 "returned %d\n", dev_name(dev),
 358				 __func__, retval);
 359	}
 360
 361	return retval;
 362}
 363
 364static const struct kset_uevent_ops device_uevent_ops = {
 365	.filter =	dev_uevent_filter,
 366	.name =		dev_uevent_name,
 367	.uevent =	dev_uevent,
 368};
 369
 370static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
 371			   char *buf)
 372{
 373	struct kobject *top_kobj;
 374	struct kset *kset;
 375	struct kobj_uevent_env *env = NULL;
 376	int i;
 377	size_t count = 0;
 378	int retval;
 379
 380	/* search the kset, the device belongs to */
 381	top_kobj = &dev->kobj;
 382	while (!top_kobj->kset && top_kobj->parent)
 383		top_kobj = top_kobj->parent;
 384	if (!top_kobj->kset)
 385		goto out;
 386
 387	kset = top_kobj->kset;
 388	if (!kset->uevent_ops || !kset->uevent_ops->uevent)
 389		goto out;
 390
 391	/* respect filter */
 392	if (kset->uevent_ops && kset->uevent_ops->filter)
 393		if (!kset->uevent_ops->filter(kset, &dev->kobj))
 394			goto out;
 395
 396	env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
 397	if (!env)
 398		return -ENOMEM;
 399
 400	/* let the kset specific function add its keys */
 401	retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
 402	if (retval)
 403		goto out;
 404
 405	/* copy keys to file */
 406	for (i = 0; i < env->envp_idx; i++)
 407		count += sprintf(&buf[count], "%s\n", env->envp[i]);
 408out:
 409	kfree(env);
 410	return count;
 411}
 412
 413static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
 414			    const char *buf, size_t count)
 415{
 416	enum kobject_action action;
 
 417
 418	if (kobject_action_type(buf, count, &action) == 0)
 419		kobject_uevent(&dev->kobj, action);
 420	else
 421		dev_err(dev, "uevent: unknown action-string\n");
 422	return count;
 423}
 424static DEVICE_ATTR_RW(uevent);
 425
 426static ssize_t online_show(struct device *dev, struct device_attribute *attr,
 427			   char *buf)
 428{
 429	bool val;
 430
 431	device_lock(dev);
 432	val = !dev->offline;
 433	device_unlock(dev);
 434	return sprintf(buf, "%u\n", val);
 435}
 436
 437static ssize_t online_store(struct device *dev, struct device_attribute *attr,
 438			    const char *buf, size_t count)
 439{
 440	bool val;
 441	int ret;
 442
 443	ret = strtobool(buf, &val);
 444	if (ret < 0)
 445		return ret;
 446
 447	ret = lock_device_hotplug_sysfs();
 448	if (ret)
 449		return ret;
 450
 451	ret = val ? device_online(dev) : device_offline(dev);
 452	unlock_device_hotplug();
 453	return ret < 0 ? ret : count;
 454}
 455static DEVICE_ATTR_RW(online);
 456
 457int device_add_groups(struct device *dev, const struct attribute_group **groups)
 458{
 459	return sysfs_create_groups(&dev->kobj, groups);
 460}
 
 461
 462void device_remove_groups(struct device *dev,
 463			  const struct attribute_group **groups)
 464{
 465	sysfs_remove_groups(&dev->kobj, groups);
 466}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 467
 468static int device_add_attrs(struct device *dev)
 469{
 470	struct class *class = dev->class;
 471	const struct device_type *type = dev->type;
 472	int error;
 473
 474	if (class) {
 475		error = device_add_groups(dev, class->dev_groups);
 476		if (error)
 477			return error;
 478	}
 479
 480	if (type) {
 481		error = device_add_groups(dev, type->groups);
 482		if (error)
 483			goto err_remove_class_groups;
 484	}
 485
 486	error = device_add_groups(dev, dev->groups);
 487	if (error)
 488		goto err_remove_type_groups;
 489
 490	if (device_supports_offline(dev) && !dev->offline_disabled) {
 491		error = device_create_file(dev, &dev_attr_online);
 492		if (error)
 493			goto err_remove_dev_groups;
 494	}
 495
 496	return 0;
 497
 498 err_remove_dev_groups:
 499	device_remove_groups(dev, dev->groups);
 500 err_remove_type_groups:
 501	if (type)
 502		device_remove_groups(dev, type->groups);
 503 err_remove_class_groups:
 504	if (class)
 505		device_remove_groups(dev, class->dev_groups);
 506
 507	return error;
 508}
 509
 510static void device_remove_attrs(struct device *dev)
 511{
 512	struct class *class = dev->class;
 513	const struct device_type *type = dev->type;
 514
 515	device_remove_file(dev, &dev_attr_online);
 516	device_remove_groups(dev, dev->groups);
 517
 518	if (type)
 519		device_remove_groups(dev, type->groups);
 520
 521	if (class)
 522		device_remove_groups(dev, class->dev_groups);
 523}
 524
 525static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
 526			char *buf)
 527{
 528	return print_dev_t(buf, dev->devt);
 529}
 530static DEVICE_ATTR_RO(dev);
 531
 532/* /sys/devices/ */
 533struct kset *devices_kset;
 534
 535/**
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 536 * device_create_file - create sysfs attribute file for device.
 537 * @dev: device.
 538 * @attr: device attribute descriptor.
 539 */
 540int device_create_file(struct device *dev,
 541		       const struct device_attribute *attr)
 542{
 543	int error = 0;
 544
 545	if (dev) {
 546		WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
 547			"Attribute %s: write permission without 'store'\n",
 548			attr->attr.name);
 549		WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
 550			"Attribute %s: read permission without 'show'\n",
 551			attr->attr.name);
 552		error = sysfs_create_file(&dev->kobj, &attr->attr);
 553	}
 554
 555	return error;
 556}
 557EXPORT_SYMBOL_GPL(device_create_file);
 558
 559/**
 560 * device_remove_file - remove sysfs attribute file.
 561 * @dev: device.
 562 * @attr: device attribute descriptor.
 563 */
 564void device_remove_file(struct device *dev,
 565			const struct device_attribute *attr)
 566{
 567	if (dev)
 568		sysfs_remove_file(&dev->kobj, &attr->attr);
 569}
 570EXPORT_SYMBOL_GPL(device_remove_file);
 571
 572/**
 573 * device_remove_file_self - remove sysfs attribute file from its own method.
 574 * @dev: device.
 575 * @attr: device attribute descriptor.
 576 *
 577 * See kernfs_remove_self() for details.
 578 */
 579bool device_remove_file_self(struct device *dev,
 580			     const struct device_attribute *attr)
 581{
 582	if (dev)
 583		return sysfs_remove_file_self(&dev->kobj, &attr->attr);
 584	else
 585		return false;
 586}
 587EXPORT_SYMBOL_GPL(device_remove_file_self);
 588
 589/**
 590 * device_create_bin_file - create sysfs binary attribute file for device.
 591 * @dev: device.
 592 * @attr: device binary attribute descriptor.
 593 */
 594int device_create_bin_file(struct device *dev,
 595			   const struct bin_attribute *attr)
 596{
 597	int error = -EINVAL;
 598	if (dev)
 599		error = sysfs_create_bin_file(&dev->kobj, attr);
 600	return error;
 601}
 602EXPORT_SYMBOL_GPL(device_create_bin_file);
 603
 604/**
 605 * device_remove_bin_file - remove sysfs binary attribute file
 606 * @dev: device.
 607 * @attr: device binary attribute descriptor.
 608 */
 609void device_remove_bin_file(struct device *dev,
 610			    const struct bin_attribute *attr)
 611{
 612	if (dev)
 613		sysfs_remove_bin_file(&dev->kobj, attr);
 614}
 615EXPORT_SYMBOL_GPL(device_remove_bin_file);
 616
 617static void klist_children_get(struct klist_node *n)
 618{
 619	struct device_private *p = to_device_private_parent(n);
 620	struct device *dev = p->device;
 621
 622	get_device(dev);
 623}
 624
 625static void klist_children_put(struct klist_node *n)
 626{
 627	struct device_private *p = to_device_private_parent(n);
 628	struct device *dev = p->device;
 629
 630	put_device(dev);
 631}
 632
 633/**
 634 * device_initialize - init device structure.
 635 * @dev: device.
 636 *
 637 * This prepares the device for use by other layers by initializing
 638 * its fields.
 639 * It is the first half of device_register(), if called by
 640 * that function, though it can also be called separately, so one
 641 * may use @dev's fields. In particular, get_device()/put_device()
 642 * may be used for reference counting of @dev after calling this
 643 * function.
 644 *
 645 * All fields in @dev must be initialized by the caller to 0, except
 646 * for those explicitly set to some other value.  The simplest
 647 * approach is to use kzalloc() to allocate the structure containing
 648 * @dev.
 649 *
 650 * NOTE: Use put_device() to give up your reference instead of freeing
 651 * @dev directly once you have called this function.
 652 */
 653void device_initialize(struct device *dev)
 654{
 655	dev->kobj.kset = devices_kset;
 656	kobject_init(&dev->kobj, &device_ktype);
 657	INIT_LIST_HEAD(&dev->dma_pools);
 658	mutex_init(&dev->mutex);
 659	lockdep_set_novalidate_class(&dev->mutex);
 660	spin_lock_init(&dev->devres_lock);
 661	INIT_LIST_HEAD(&dev->devres_head);
 662	device_pm_init(dev);
 663	set_dev_node(dev, -1);
 
 
 
 
 
 
 664}
 665EXPORT_SYMBOL_GPL(device_initialize);
 666
 667struct kobject *virtual_device_parent(struct device *dev)
 668{
 669	static struct kobject *virtual_dir = NULL;
 670
 671	if (!virtual_dir)
 672		virtual_dir = kobject_create_and_add("virtual",
 673						     &devices_kset->kobj);
 674
 675	return virtual_dir;
 676}
 677
 678struct class_dir {
 679	struct kobject kobj;
 680	struct class *class;
 681};
 682
 683#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
 684
 685static void class_dir_release(struct kobject *kobj)
 686{
 687	struct class_dir *dir = to_class_dir(kobj);
 688	kfree(dir);
 689}
 690
 691static const
 692struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
 693{
 694	struct class_dir *dir = to_class_dir(kobj);
 695	return dir->class->ns_type;
 696}
 697
 698static struct kobj_type class_dir_ktype = {
 699	.release	= class_dir_release,
 700	.sysfs_ops	= &kobj_sysfs_ops,
 701	.child_ns_type	= class_dir_child_ns_type
 702};
 703
 704static struct kobject *
 705class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
 706{
 707	struct class_dir *dir;
 708	int retval;
 709
 710	dir = kzalloc(sizeof(*dir), GFP_KERNEL);
 711	if (!dir)
 712		return NULL;
 713
 714	dir->class = class;
 715	kobject_init(&dir->kobj, &class_dir_ktype);
 716
 717	dir->kobj.kset = &class->p->glue_dirs;
 718
 719	retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
 720	if (retval < 0) {
 721		kobject_put(&dir->kobj);
 722		return NULL;
 723	}
 724	return &dir->kobj;
 725}
 726
 
 727
 728static struct kobject *get_device_parent(struct device *dev,
 729					 struct device *parent)
 730{
 731	if (dev->class) {
 732		static DEFINE_MUTEX(gdp_mutex);
 733		struct kobject *kobj = NULL;
 734		struct kobject *parent_kobj;
 735		struct kobject *k;
 736
 737#ifdef CONFIG_BLOCK
 738		/* block disks show up in /sys/block */
 739		if (sysfs_deprecated && dev->class == &block_class) {
 740			if (parent && parent->class == &block_class)
 741				return &parent->kobj;
 742			return &block_class.p->subsys.kobj;
 743		}
 744#endif
 745
 746		/*
 747		 * If we have no parent, we live in "virtual".
 748		 * Class-devices with a non class-device as parent, live
 749		 * in a "glue" directory to prevent namespace collisions.
 750		 */
 751		if (parent == NULL)
 752			parent_kobj = virtual_device_parent(dev);
 753		else if (parent->class && !dev->class->ns_type)
 754			return &parent->kobj;
 755		else
 756			parent_kobj = &parent->kobj;
 757
 758		mutex_lock(&gdp_mutex);
 759
 760		/* find our class-directory at the parent and reference it */
 761		spin_lock(&dev->class->p->glue_dirs.list_lock);
 762		list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
 763			if (k->parent == parent_kobj) {
 764				kobj = kobject_get(k);
 765				break;
 766			}
 767		spin_unlock(&dev->class->p->glue_dirs.list_lock);
 768		if (kobj) {
 769			mutex_unlock(&gdp_mutex);
 770			return kobj;
 771		}
 772
 773		/* or create a new class-directory at the parent device */
 774		k = class_dir_create_and_add(dev->class, parent_kobj);
 775		/* do not emit an uevent for this simple "glue" directory */
 776		mutex_unlock(&gdp_mutex);
 777		return k;
 778	}
 779
 780	/* subsystems can specify a default root directory for their devices */
 781	if (!parent && dev->bus && dev->bus->dev_root)
 782		return &dev->bus->dev_root->kobj;
 783
 784	if (parent)
 785		return &parent->kobj;
 786	return NULL;
 787}
 788
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 789static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
 790{
 791	/* see if we live in a "glue" directory */
 792	if (!glue_dir || !dev->class ||
 793	    glue_dir->kset != &dev->class->p->glue_dirs)
 794		return;
 795
 
 796	kobject_put(glue_dir);
 797}
 798
 799static void cleanup_device_parent(struct device *dev)
 800{
 801	cleanup_glue_dir(dev, dev->kobj.parent);
 802}
 803
 804static int device_add_class_symlinks(struct device *dev)
 805{
 
 806	int error;
 807
 
 
 
 
 
 
 
 808	if (!dev->class)
 809		return 0;
 810
 811	error = sysfs_create_link(&dev->kobj,
 812				  &dev->class->p->subsys.kobj,
 813				  "subsystem");
 814	if (error)
 815		goto out;
 816
 817	if (dev->parent && device_is_not_partition(dev)) {
 818		error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
 819					  "device");
 820		if (error)
 821			goto out_subsys;
 822	}
 823
 824#ifdef CONFIG_BLOCK
 825	/* /sys/block has directories and does not need symlinks */
 826	if (sysfs_deprecated && dev->class == &block_class)
 827		return 0;
 828#endif
 829
 830	/* link in the class directory pointing to the device */
 831	error = sysfs_create_link(&dev->class->p->subsys.kobj,
 832				  &dev->kobj, dev_name(dev));
 833	if (error)
 834		goto out_device;
 835
 836	return 0;
 837
 838out_device:
 839	sysfs_remove_link(&dev->kobj, "device");
 840
 841out_subsys:
 842	sysfs_remove_link(&dev->kobj, "subsystem");
 843out:
 
 844	return error;
 845}
 846
 847static void device_remove_class_symlinks(struct device *dev)
 848{
 
 
 
 849	if (!dev->class)
 850		return;
 851
 852	if (dev->parent && device_is_not_partition(dev))
 853		sysfs_remove_link(&dev->kobj, "device");
 854	sysfs_remove_link(&dev->kobj, "subsystem");
 855#ifdef CONFIG_BLOCK
 856	if (sysfs_deprecated && dev->class == &block_class)
 857		return;
 858#endif
 859	sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
 860}
 861
 862/**
 863 * dev_set_name - set a device name
 864 * @dev: device
 865 * @fmt: format string for the device's name
 866 */
 867int dev_set_name(struct device *dev, const char *fmt, ...)
 868{
 869	va_list vargs;
 870	int err;
 871
 872	va_start(vargs, fmt);
 873	err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
 874	va_end(vargs);
 875	return err;
 876}
 877EXPORT_SYMBOL_GPL(dev_set_name);
 878
 879/**
 880 * device_to_dev_kobj - select a /sys/dev/ directory for the device
 881 * @dev: device
 882 *
 883 * By default we select char/ for new entries.  Setting class->dev_obj
 884 * to NULL prevents an entry from being created.  class->dev_kobj must
 885 * be set (or cleared) before any devices are registered to the class
 886 * otherwise device_create_sys_dev_entry() and
 887 * device_remove_sys_dev_entry() will disagree about the presence of
 888 * the link.
 889 */
 890static struct kobject *device_to_dev_kobj(struct device *dev)
 891{
 892	struct kobject *kobj;
 893
 894	if (dev->class)
 895		kobj = dev->class->dev_kobj;
 896	else
 897		kobj = sysfs_dev_char_kobj;
 898
 899	return kobj;
 900}
 901
 902static int device_create_sys_dev_entry(struct device *dev)
 903{
 904	struct kobject *kobj = device_to_dev_kobj(dev);
 905	int error = 0;
 906	char devt_str[15];
 907
 908	if (kobj) {
 909		format_dev_t(devt_str, dev->devt);
 910		error = sysfs_create_link(kobj, &dev->kobj, devt_str);
 911	}
 912
 913	return error;
 914}
 915
 916static void device_remove_sys_dev_entry(struct device *dev)
 917{
 918	struct kobject *kobj = device_to_dev_kobj(dev);
 919	char devt_str[15];
 920
 921	if (kobj) {
 922		format_dev_t(devt_str, dev->devt);
 923		sysfs_remove_link(kobj, devt_str);
 924	}
 925}
 926
 927int device_private_init(struct device *dev)
 928{
 929	dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
 930	if (!dev->p)
 931		return -ENOMEM;
 932	dev->p->device = dev;
 933	klist_init(&dev->p->klist_children, klist_children_get,
 934		   klist_children_put);
 935	INIT_LIST_HEAD(&dev->p->deferred_probe);
 936	return 0;
 937}
 938
 939/**
 940 * device_add - add device to device hierarchy.
 941 * @dev: device.
 942 *
 943 * This is part 2 of device_register(), though may be called
 944 * separately _iff_ device_initialize() has been called separately.
 945 *
 946 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
 947 * to the global and sibling lists for the device, then
 948 * adds it to the other relevant subsystems of the driver model.
 949 *
 950 * Do not call this routine or device_register() more than once for
 951 * any device structure.  The driver model core is not designed to work
 952 * with devices that get unregistered and then spring back to life.
 953 * (Among other things, it's very hard to guarantee that all references
 954 * to the previous incarnation of @dev have been dropped.)  Allocate
 955 * and register a fresh new struct device instead.
 956 *
 957 * NOTE: _Never_ directly free @dev after calling this function, even
 958 * if it returned an error! Always use put_device() to give up your
 959 * reference instead.
 960 */
 961int device_add(struct device *dev)
 962{
 963	struct device *parent = NULL;
 964	struct kobject *kobj;
 965	struct class_interface *class_intf;
 966	int error = -EINVAL;
 
 967
 968	dev = get_device(dev);
 969	if (!dev)
 970		goto done;
 971
 972	if (!dev->p) {
 973		error = device_private_init(dev);
 974		if (error)
 975			goto done;
 976	}
 977
 978	/*
 979	 * for statically allocated devices, which should all be converted
 980	 * some day, we need to initialize the name. We prevent reading back
 981	 * the name, and force the use of dev_name()
 982	 */
 983	if (dev->init_name) {
 984		dev_set_name(dev, "%s", dev->init_name);
 985		dev->init_name = NULL;
 986	}
 987
 988	/* subsystems can specify simple device enumeration */
 989	if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
 990		dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
 991
 992	if (!dev_name(dev)) {
 993		error = -EINVAL;
 994		goto name_error;
 995	}
 996
 997	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
 998
 999	parent = get_device(dev->parent);
1000	kobj = get_device_parent(dev, parent);
1001	if (kobj)
1002		dev->kobj.parent = kobj;
1003
1004	/* use parent numa_node */
1005	if (parent)
1006		set_dev_node(dev, dev_to_node(parent));
1007
1008	/* first, register with generic layer. */
1009	/* we require the name to be set before, and pass NULL */
1010	error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
1011	if (error)
 
1012		goto Error;
 
1013
1014	/* notify platform of device entry */
1015	if (platform_notify)
1016		platform_notify(dev);
1017
1018	error = device_create_file(dev, &dev_attr_uevent);
1019	if (error)
1020		goto attrError;
1021
1022	if (MAJOR(dev->devt)) {
1023		error = device_create_file(dev, &dev_attr_dev);
1024		if (error)
1025			goto ueventattrError;
1026
1027		error = device_create_sys_dev_entry(dev);
1028		if (error)
1029			goto devtattrError;
1030
1031		devtmpfs_create_node(dev);
1032	}
1033
1034	error = device_add_class_symlinks(dev);
1035	if (error)
1036		goto SymlinkError;
1037	error = device_add_attrs(dev);
1038	if (error)
1039		goto AttrsError;
1040	error = bus_add_device(dev);
1041	if (error)
1042		goto BusError;
1043	error = dpm_sysfs_add(dev);
1044	if (error)
1045		goto DPMError;
1046	device_pm_add(dev);
1047
 
 
 
 
 
 
 
 
 
 
 
 
1048	/* Notify clients of device addition.  This call must come
1049	 * after dpm_sysfs_add() and before kobject_uevent().
1050	 */
1051	if (dev->bus)
1052		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1053					     BUS_NOTIFY_ADD_DEVICE, dev);
1054
1055	kobject_uevent(&dev->kobj, KOBJ_ADD);
1056	bus_probe_device(dev);
1057	if (parent)
1058		klist_add_tail(&dev->p->knode_parent,
1059			       &parent->p->klist_children);
1060
1061	if (dev->class) {
1062		mutex_lock(&dev->class->p->mutex);
1063		/* tie the class to the device */
1064		klist_add_tail(&dev->knode_class,
1065			       &dev->class->p->klist_devices);
1066
1067		/* notify any interfaces that the device is here */
1068		list_for_each_entry(class_intf,
1069				    &dev->class->p->interfaces, node)
1070			if (class_intf->add_dev)
1071				class_intf->add_dev(dev, class_intf);
1072		mutex_unlock(&dev->class->p->mutex);
1073	}
1074done:
1075	put_device(dev);
1076	return error;
 
 
 
 
 
 
1077 DPMError:
1078	bus_remove_device(dev);
1079 BusError:
1080	device_remove_attrs(dev);
1081 AttrsError:
1082	device_remove_class_symlinks(dev);
1083 SymlinkError:
1084	if (MAJOR(dev->devt))
1085		devtmpfs_delete_node(dev);
1086	if (MAJOR(dev->devt))
1087		device_remove_sys_dev_entry(dev);
1088 devtattrError:
1089	if (MAJOR(dev->devt))
1090		device_remove_file(dev, &dev_attr_dev);
1091 ueventattrError:
1092	device_remove_file(dev, &dev_attr_uevent);
1093 attrError:
1094	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
 
1095	kobject_del(&dev->kobj);
1096 Error:
1097	cleanup_device_parent(dev);
1098	if (parent)
1099		put_device(parent);
1100name_error:
1101	kfree(dev->p);
1102	dev->p = NULL;
1103	goto done;
1104}
1105EXPORT_SYMBOL_GPL(device_add);
1106
1107/**
1108 * device_register - register a device with the system.
1109 * @dev: pointer to the device structure
1110 *
1111 * This happens in two clean steps - initialize the device
1112 * and add it to the system. The two steps can be called
1113 * separately, but this is the easiest and most common.
1114 * I.e. you should only call the two helpers separately if
1115 * have a clearly defined need to use and refcount the device
1116 * before it is added to the hierarchy.
1117 *
1118 * For more information, see the kerneldoc for device_initialize()
1119 * and device_add().
1120 *
1121 * NOTE: _Never_ directly free @dev after calling this function, even
1122 * if it returned an error! Always use put_device() to give up the
1123 * reference initialized in this function instead.
1124 */
1125int device_register(struct device *dev)
1126{
1127	device_initialize(dev);
1128	return device_add(dev);
1129}
1130EXPORT_SYMBOL_GPL(device_register);
1131
1132/**
1133 * get_device - increment reference count for device.
1134 * @dev: device.
1135 *
1136 * This simply forwards the call to kobject_get(), though
1137 * we do take care to provide for the case that we get a NULL
1138 * pointer passed in.
1139 */
1140struct device *get_device(struct device *dev)
1141{
1142	return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
1143}
1144EXPORT_SYMBOL_GPL(get_device);
1145
1146/**
1147 * put_device - decrement reference count.
1148 * @dev: device in question.
1149 */
1150void put_device(struct device *dev)
1151{
1152	/* might_sleep(); */
1153	if (dev)
1154		kobject_put(&dev->kobj);
1155}
1156EXPORT_SYMBOL_GPL(put_device);
1157
1158/**
1159 * device_del - delete device from system.
1160 * @dev: device.
1161 *
1162 * This is the first part of the device unregistration
1163 * sequence. This removes the device from the lists we control
1164 * from here, has it removed from the other driver model
1165 * subsystems it was added to in device_add(), and removes it
1166 * from the kobject hierarchy.
1167 *
1168 * NOTE: this should be called manually _iff_ device_add() was
1169 * also called manually.
1170 */
1171void device_del(struct device *dev)
1172{
1173	struct device *parent = dev->parent;
 
1174	struct class_interface *class_intf;
1175
1176	/* Notify clients of device removal.  This call must come
1177	 * before dpm_sysfs_remove().
1178	 */
1179	if (dev->bus)
1180		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1181					     BUS_NOTIFY_DEL_DEVICE, dev);
 
1182	dpm_sysfs_remove(dev);
1183	if (parent)
1184		klist_del(&dev->p->knode_parent);
1185	if (MAJOR(dev->devt)) {
1186		devtmpfs_delete_node(dev);
1187		device_remove_sys_dev_entry(dev);
1188		device_remove_file(dev, &dev_attr_dev);
1189	}
1190	if (dev->class) {
1191		device_remove_class_symlinks(dev);
1192
1193		mutex_lock(&dev->class->p->mutex);
1194		/* notify any interfaces that the device is now gone */
1195		list_for_each_entry(class_intf,
1196				    &dev->class->p->interfaces, node)
1197			if (class_intf->remove_dev)
1198				class_intf->remove_dev(dev, class_intf);
1199		/* remove the device from the class list */
1200		klist_del(&dev->knode_class);
1201		mutex_unlock(&dev->class->p->mutex);
1202	}
1203	device_remove_file(dev, &dev_attr_uevent);
1204	device_remove_attrs(dev);
1205	bus_remove_device(dev);
1206	device_pm_remove(dev);
1207	driver_deferred_probe_del(dev);
 
 
1208
1209	/* Notify the platform of the removal, in case they
1210	 * need to do anything...
1211	 */
1212	if (platform_notify_remove)
1213		platform_notify_remove(dev);
 
 
 
1214	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1215	cleanup_device_parent(dev);
1216	kobject_del(&dev->kobj);
 
1217	put_device(parent);
1218}
1219EXPORT_SYMBOL_GPL(device_del);
1220
1221/**
1222 * device_unregister - unregister device from system.
1223 * @dev: device going away.
1224 *
1225 * We do this in two parts, like we do device_register(). First,
1226 * we remove it from all the subsystems with device_del(), then
1227 * we decrement the reference count via put_device(). If that
1228 * is the final reference count, the device will be cleaned up
1229 * via device_release() above. Otherwise, the structure will
1230 * stick around until the final reference to the device is dropped.
1231 */
1232void device_unregister(struct device *dev)
1233{
1234	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1235	device_del(dev);
1236	put_device(dev);
1237}
1238EXPORT_SYMBOL_GPL(device_unregister);
1239
 
 
 
 
 
 
 
 
 
 
 
 
 
1240static struct device *next_device(struct klist_iter *i)
1241{
1242	struct klist_node *n = klist_next(i);
1243	struct device *dev = NULL;
1244	struct device_private *p;
1245
1246	if (n) {
1247		p = to_device_private_parent(n);
1248		dev = p->device;
1249	}
1250	return dev;
1251}
1252
1253/**
1254 * device_get_devnode - path of device node file
1255 * @dev: device
1256 * @mode: returned file access mode
1257 * @uid: returned file owner
1258 * @gid: returned file group
1259 * @tmp: possibly allocated string
1260 *
1261 * Return the relative path of a possible device node.
1262 * Non-default names may need to allocate a memory to compose
1263 * a name. This memory is returned in tmp and needs to be
1264 * freed by the caller.
1265 */
1266const char *device_get_devnode(struct device *dev,
1267			       umode_t *mode, kuid_t *uid, kgid_t *gid,
1268			       const char **tmp)
1269{
1270	char *s;
1271
1272	*tmp = NULL;
1273
1274	/* the device type may provide a specific name */
1275	if (dev->type && dev->type->devnode)
1276		*tmp = dev->type->devnode(dev, mode, uid, gid);
1277	if (*tmp)
1278		return *tmp;
1279
1280	/* the class may provide a specific name */
1281	if (dev->class && dev->class->devnode)
1282		*tmp = dev->class->devnode(dev, mode);
1283	if (*tmp)
1284		return *tmp;
1285
1286	/* return name without allocation, tmp == NULL */
1287	if (strchr(dev_name(dev), '!') == NULL)
1288		return dev_name(dev);
1289
1290	/* replace '!' in the name with '/' */
1291	*tmp = kstrdup(dev_name(dev), GFP_KERNEL);
1292	if (!*tmp)
1293		return NULL;
1294	while ((s = strchr(*tmp, '!')))
1295		s[0] = '/';
1296	return *tmp;
1297}
1298
1299/**
1300 * device_for_each_child - device child iterator.
1301 * @parent: parent struct device.
1302 * @fn: function to be called for each device.
1303 * @data: data for the callback.
1304 *
1305 * Iterate over @parent's child devices, and call @fn for each,
1306 * passing it @data.
1307 *
1308 * We check the return of @fn each time. If it returns anything
1309 * other than 0, we break out and return that value.
1310 */
1311int device_for_each_child(struct device *parent, void *data,
1312			  int (*fn)(struct device *dev, void *data))
1313{
1314	struct klist_iter i;
1315	struct device *child;
1316	int error = 0;
1317
1318	if (!parent->p)
1319		return 0;
1320
1321	klist_iter_init(&parent->p->klist_children, &i);
1322	while ((child = next_device(&i)) && !error)
1323		error = fn(child, data);
1324	klist_iter_exit(&i);
1325	return error;
1326}
1327EXPORT_SYMBOL_GPL(device_for_each_child);
1328
1329/**
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1330 * device_find_child - device iterator for locating a particular device.
1331 * @parent: parent struct device
1332 * @match: Callback function to check device
1333 * @data: Data to pass to match function
1334 *
1335 * This is similar to the device_for_each_child() function above, but it
1336 * returns a reference to a device that is 'found' for later use, as
1337 * determined by the @match callback.
1338 *
1339 * The callback should return 0 if the device doesn't match and non-zero
1340 * if it does.  If the callback returns non-zero and a reference to the
1341 * current device can be obtained, this function will return to the caller
1342 * and not iterate over any more devices.
1343 *
1344 * NOTE: you will need to drop the reference with put_device() after use.
1345 */
1346struct device *device_find_child(struct device *parent, void *data,
1347				 int (*match)(struct device *dev, void *data))
1348{
1349	struct klist_iter i;
1350	struct device *child;
1351
1352	if (!parent)
1353		return NULL;
1354
1355	klist_iter_init(&parent->p->klist_children, &i);
1356	while ((child = next_device(&i)))
1357		if (match(child, data) && get_device(child))
1358			break;
1359	klist_iter_exit(&i);
1360	return child;
1361}
1362EXPORT_SYMBOL_GPL(device_find_child);
1363
1364int __init devices_init(void)
1365{
1366	devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
1367	if (!devices_kset)
1368		return -ENOMEM;
1369	dev_kobj = kobject_create_and_add("dev", NULL);
1370	if (!dev_kobj)
1371		goto dev_kobj_err;
1372	sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
1373	if (!sysfs_dev_block_kobj)
1374		goto block_kobj_err;
1375	sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
1376	if (!sysfs_dev_char_kobj)
1377		goto char_kobj_err;
1378
1379	return 0;
1380
1381 char_kobj_err:
1382	kobject_put(sysfs_dev_block_kobj);
1383 block_kobj_err:
1384	kobject_put(dev_kobj);
1385 dev_kobj_err:
1386	kset_unregister(devices_kset);
1387	return -ENOMEM;
1388}
1389
1390static int device_check_offline(struct device *dev, void *not_used)
1391{
1392	int ret;
1393
1394	ret = device_for_each_child(dev, NULL, device_check_offline);
1395	if (ret)
1396		return ret;
1397
1398	return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
1399}
1400
1401/**
1402 * device_offline - Prepare the device for hot-removal.
1403 * @dev: Device to be put offline.
1404 *
1405 * Execute the device bus type's .offline() callback, if present, to prepare
1406 * the device for a subsequent hot-removal.  If that succeeds, the device must
1407 * not be used until either it is removed or its bus type's .online() callback
1408 * is executed.
1409 *
1410 * Call under device_hotplug_lock.
1411 */
1412int device_offline(struct device *dev)
1413{
1414	int ret;
1415
1416	if (dev->offline_disabled)
1417		return -EPERM;
1418
1419	ret = device_for_each_child(dev, NULL, device_check_offline);
1420	if (ret)
1421		return ret;
1422
1423	device_lock(dev);
1424	if (device_supports_offline(dev)) {
1425		if (dev->offline) {
1426			ret = 1;
1427		} else {
1428			ret = dev->bus->offline(dev);
1429			if (!ret) {
1430				kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
1431				dev->offline = true;
1432			}
1433		}
1434	}
1435	device_unlock(dev);
1436
1437	return ret;
1438}
1439
1440/**
1441 * device_online - Put the device back online after successful device_offline().
1442 * @dev: Device to be put back online.
1443 *
1444 * If device_offline() has been successfully executed for @dev, but the device
1445 * has not been removed subsequently, execute its bus type's .online() callback
1446 * to indicate that the device can be used again.
1447 *
1448 * Call under device_hotplug_lock.
1449 */
1450int device_online(struct device *dev)
1451{
1452	int ret = 0;
1453
1454	device_lock(dev);
1455	if (device_supports_offline(dev)) {
1456		if (dev->offline) {
1457			ret = dev->bus->online(dev);
1458			if (!ret) {
1459				kobject_uevent(&dev->kobj, KOBJ_ONLINE);
1460				dev->offline = false;
1461			}
1462		} else {
1463			ret = 1;
1464		}
1465	}
1466	device_unlock(dev);
1467
1468	return ret;
1469}
1470
1471struct root_device {
1472	struct device dev;
1473	struct module *owner;
1474};
1475
1476static inline struct root_device *to_root_device(struct device *d)
1477{
1478	return container_of(d, struct root_device, dev);
1479}
1480
1481static void root_device_release(struct device *dev)
1482{
1483	kfree(to_root_device(dev));
1484}
1485
1486/**
1487 * __root_device_register - allocate and register a root device
1488 * @name: root device name
1489 * @owner: owner module of the root device, usually THIS_MODULE
1490 *
1491 * This function allocates a root device and registers it
1492 * using device_register(). In order to free the returned
1493 * device, use root_device_unregister().
1494 *
1495 * Root devices are dummy devices which allow other devices
1496 * to be grouped under /sys/devices. Use this function to
1497 * allocate a root device and then use it as the parent of
1498 * any device which should appear under /sys/devices/{name}
1499 *
1500 * The /sys/devices/{name} directory will also contain a
1501 * 'module' symlink which points to the @owner directory
1502 * in sysfs.
1503 *
1504 * Returns &struct device pointer on success, or ERR_PTR() on error.
1505 *
1506 * Note: You probably want to use root_device_register().
1507 */
1508struct device *__root_device_register(const char *name, struct module *owner)
1509{
1510	struct root_device *root;
1511	int err = -ENOMEM;
1512
1513	root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
1514	if (!root)
1515		return ERR_PTR(err);
1516
1517	err = dev_set_name(&root->dev, "%s", name);
1518	if (err) {
1519		kfree(root);
1520		return ERR_PTR(err);
1521	}
1522
1523	root->dev.release = root_device_release;
1524
1525	err = device_register(&root->dev);
1526	if (err) {
1527		put_device(&root->dev);
1528		return ERR_PTR(err);
1529	}
1530
1531#ifdef CONFIG_MODULES	/* gotta find a "cleaner" way to do this */
1532	if (owner) {
1533		struct module_kobject *mk = &owner->mkobj;
1534
1535		err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
1536		if (err) {
1537			device_unregister(&root->dev);
1538			return ERR_PTR(err);
1539		}
1540		root->owner = owner;
1541	}
1542#endif
1543
1544	return &root->dev;
1545}
1546EXPORT_SYMBOL_GPL(__root_device_register);
1547
1548/**
1549 * root_device_unregister - unregister and free a root device
1550 * @dev: device going away
1551 *
1552 * This function unregisters and cleans up a device that was created by
1553 * root_device_register().
1554 */
1555void root_device_unregister(struct device *dev)
1556{
1557	struct root_device *root = to_root_device(dev);
1558
1559	if (root->owner)
1560		sysfs_remove_link(&root->dev.kobj, "module");
1561
1562	device_unregister(dev);
1563}
1564EXPORT_SYMBOL_GPL(root_device_unregister);
1565
1566
1567static void device_create_release(struct device *dev)
1568{
1569	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1570	kfree(dev);
1571}
1572
1573static struct device *
1574device_create_groups_vargs(struct class *class, struct device *parent,
1575			   dev_t devt, void *drvdata,
1576			   const struct attribute_group **groups,
1577			   const char *fmt, va_list args)
1578{
1579	struct device *dev = NULL;
1580	int retval = -ENODEV;
1581
1582	if (class == NULL || IS_ERR(class))
1583		goto error;
1584
1585	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1586	if (!dev) {
1587		retval = -ENOMEM;
1588		goto error;
1589	}
1590
1591	device_initialize(dev);
1592	dev->devt = devt;
1593	dev->class = class;
1594	dev->parent = parent;
1595	dev->groups = groups;
1596	dev->release = device_create_release;
1597	dev_set_drvdata(dev, drvdata);
1598
1599	retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
1600	if (retval)
1601		goto error;
1602
1603	retval = device_add(dev);
1604	if (retval)
1605		goto error;
1606
1607	return dev;
1608
1609error:
1610	put_device(dev);
1611	return ERR_PTR(retval);
1612}
1613
1614/**
1615 * device_create_vargs - creates a device and registers it with sysfs
1616 * @class: pointer to the struct class that this device should be registered to
1617 * @parent: pointer to the parent struct device of this new device, if any
1618 * @devt: the dev_t for the char device to be added
1619 * @drvdata: the data to be added to the device for callbacks
1620 * @fmt: string for the device's name
1621 * @args: va_list for the device's name
1622 *
1623 * This function can be used by char device classes.  A struct device
1624 * will be created in sysfs, registered to the specified class.
1625 *
1626 * A "dev" file will be created, showing the dev_t for the device, if
1627 * the dev_t is not 0,0.
1628 * If a pointer to a parent struct device is passed in, the newly created
1629 * struct device will be a child of that device in sysfs.
1630 * The pointer to the struct device will be returned from the call.
1631 * Any further sysfs files that might be required can be created using this
1632 * pointer.
1633 *
1634 * Returns &struct device pointer on success, or ERR_PTR() on error.
1635 *
1636 * Note: the struct class passed to this function must have previously
1637 * been created with a call to class_create().
1638 */
1639struct device *device_create_vargs(struct class *class, struct device *parent,
1640				   dev_t devt, void *drvdata, const char *fmt,
1641				   va_list args)
1642{
1643	return device_create_groups_vargs(class, parent, devt, drvdata, NULL,
1644					  fmt, args);
1645}
1646EXPORT_SYMBOL_GPL(device_create_vargs);
1647
1648/**
1649 * device_create - creates a device and registers it with sysfs
1650 * @class: pointer to the struct class that this device should be registered to
1651 * @parent: pointer to the parent struct device of this new device, if any
1652 * @devt: the dev_t for the char device to be added
1653 * @drvdata: the data to be added to the device for callbacks
1654 * @fmt: string for the device's name
1655 *
1656 * This function can be used by char device classes.  A struct device
1657 * will be created in sysfs, registered to the specified class.
1658 *
1659 * A "dev" file will be created, showing the dev_t for the device, if
1660 * the dev_t is not 0,0.
1661 * If a pointer to a parent struct device is passed in, the newly created
1662 * struct device will be a child of that device in sysfs.
1663 * The pointer to the struct device will be returned from the call.
1664 * Any further sysfs files that might be required can be created using this
1665 * pointer.
1666 *
1667 * Returns &struct device pointer on success, or ERR_PTR() on error.
1668 *
1669 * Note: the struct class passed to this function must have previously
1670 * been created with a call to class_create().
1671 */
1672struct device *device_create(struct class *class, struct device *parent,
1673			     dev_t devt, void *drvdata, const char *fmt, ...)
1674{
1675	va_list vargs;
1676	struct device *dev;
1677
1678	va_start(vargs, fmt);
1679	dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
1680	va_end(vargs);
1681	return dev;
1682}
1683EXPORT_SYMBOL_GPL(device_create);
1684
1685/**
1686 * device_create_with_groups - creates a device and registers it with sysfs
1687 * @class: pointer to the struct class that this device should be registered to
1688 * @parent: pointer to the parent struct device of this new device, if any
1689 * @devt: the dev_t for the char device to be added
1690 * @drvdata: the data to be added to the device for callbacks
1691 * @groups: NULL-terminated list of attribute groups to be created
1692 * @fmt: string for the device's name
1693 *
1694 * This function can be used by char device classes.  A struct device
1695 * will be created in sysfs, registered to the specified class.
1696 * Additional attributes specified in the groups parameter will also
1697 * be created automatically.
1698 *
1699 * A "dev" file will be created, showing the dev_t for the device, if
1700 * the dev_t is not 0,0.
1701 * If a pointer to a parent struct device is passed in, the newly created
1702 * struct device will be a child of that device in sysfs.
1703 * The pointer to the struct device will be returned from the call.
1704 * Any further sysfs files that might be required can be created using this
1705 * pointer.
1706 *
1707 * Returns &struct device pointer on success, or ERR_PTR() on error.
1708 *
1709 * Note: the struct class passed to this function must have previously
1710 * been created with a call to class_create().
1711 */
1712struct device *device_create_with_groups(struct class *class,
1713					 struct device *parent, dev_t devt,
1714					 void *drvdata,
1715					 const struct attribute_group **groups,
1716					 const char *fmt, ...)
1717{
1718	va_list vargs;
1719	struct device *dev;
1720
1721	va_start(vargs, fmt);
1722	dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
1723					 fmt, vargs);
1724	va_end(vargs);
1725	return dev;
1726}
1727EXPORT_SYMBOL_GPL(device_create_with_groups);
1728
1729static int __match_devt(struct device *dev, const void *data)
1730{
1731	const dev_t *devt = data;
1732
1733	return dev->devt == *devt;
1734}
1735
1736/**
1737 * device_destroy - removes a device that was created with device_create()
1738 * @class: pointer to the struct class that this device was registered with
1739 * @devt: the dev_t of the device that was previously registered
1740 *
1741 * This call unregisters and cleans up a device that was created with a
1742 * call to device_create().
1743 */
1744void device_destroy(struct class *class, dev_t devt)
1745{
1746	struct device *dev;
1747
1748	dev = class_find_device(class, NULL, &devt, __match_devt);
1749	if (dev) {
1750		put_device(dev);
1751		device_unregister(dev);
1752	}
1753}
1754EXPORT_SYMBOL_GPL(device_destroy);
1755
1756/**
1757 * device_rename - renames a device
1758 * @dev: the pointer to the struct device to be renamed
1759 * @new_name: the new name of the device
1760 *
1761 * It is the responsibility of the caller to provide mutual
1762 * exclusion between two different calls of device_rename
1763 * on the same device to ensure that new_name is valid and
1764 * won't conflict with other devices.
1765 *
1766 * Note: Don't call this function.  Currently, the networking layer calls this
1767 * function, but that will change.  The following text from Kay Sievers offers
1768 * some insight:
1769 *
1770 * Renaming devices is racy at many levels, symlinks and other stuff are not
1771 * replaced atomically, and you get a "move" uevent, but it's not easy to
1772 * connect the event to the old and new device. Device nodes are not renamed at
1773 * all, there isn't even support for that in the kernel now.
1774 *
1775 * In the meantime, during renaming, your target name might be taken by another
1776 * driver, creating conflicts. Or the old name is taken directly after you
1777 * renamed it -- then you get events for the same DEVPATH, before you even see
1778 * the "move" event. It's just a mess, and nothing new should ever rely on
1779 * kernel device renaming. Besides that, it's not even implemented now for
1780 * other things than (driver-core wise very simple) network devices.
1781 *
1782 * We are currently about to change network renaming in udev to completely
1783 * disallow renaming of devices in the same namespace as the kernel uses,
1784 * because we can't solve the problems properly, that arise with swapping names
1785 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
1786 * be allowed to some other name than eth[0-9]*, for the aforementioned
1787 * reasons.
1788 *
1789 * Make up a "real" name in the driver before you register anything, or add
1790 * some other attributes for userspace to find the device, or use udev to add
1791 * symlinks -- but never rename kernel devices later, it's a complete mess. We
1792 * don't even want to get into that and try to implement the missing pieces in
1793 * the core. We really have other pieces to fix in the driver core mess. :)
1794 */
1795int device_rename(struct device *dev, const char *new_name)
1796{
1797	struct kobject *kobj = &dev->kobj;
1798	char *old_device_name = NULL;
1799	int error;
1800
1801	dev = get_device(dev);
1802	if (!dev)
1803		return -EINVAL;
1804
1805	dev_dbg(dev, "renaming to %s\n", new_name);
1806
1807	old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
1808	if (!old_device_name) {
1809		error = -ENOMEM;
1810		goto out;
1811	}
1812
1813	if (dev->class) {
1814		error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
1815					     kobj, old_device_name,
1816					     new_name, kobject_namespace(kobj));
1817		if (error)
1818			goto out;
1819	}
1820
1821	error = kobject_rename(kobj, new_name);
1822	if (error)
1823		goto out;
1824
1825out:
1826	put_device(dev);
1827
1828	kfree(old_device_name);
1829
1830	return error;
1831}
1832EXPORT_SYMBOL_GPL(device_rename);
1833
1834static int device_move_class_links(struct device *dev,
1835				   struct device *old_parent,
1836				   struct device *new_parent)
1837{
1838	int error = 0;
1839
1840	if (old_parent)
1841		sysfs_remove_link(&dev->kobj, "device");
1842	if (new_parent)
1843		error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1844					  "device");
1845	return error;
1846}
1847
1848/**
1849 * device_move - moves a device to a new parent
1850 * @dev: the pointer to the struct device to be moved
1851 * @new_parent: the new parent of the device (can by NULL)
1852 * @dpm_order: how to reorder the dpm_list
1853 */
1854int device_move(struct device *dev, struct device *new_parent,
1855		enum dpm_order dpm_order)
1856{
1857	int error;
1858	struct device *old_parent;
1859	struct kobject *new_parent_kobj;
1860
1861	dev = get_device(dev);
1862	if (!dev)
1863		return -EINVAL;
1864
1865	device_pm_lock();
1866	new_parent = get_device(new_parent);
1867	new_parent_kobj = get_device_parent(dev, new_parent);
1868
1869	pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
1870		 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
1871	error = kobject_move(&dev->kobj, new_parent_kobj);
1872	if (error) {
1873		cleanup_glue_dir(dev, new_parent_kobj);
1874		put_device(new_parent);
1875		goto out;
1876	}
1877	old_parent = dev->parent;
1878	dev->parent = new_parent;
1879	if (old_parent)
1880		klist_remove(&dev->p->knode_parent);
1881	if (new_parent) {
1882		klist_add_tail(&dev->p->knode_parent,
1883			       &new_parent->p->klist_children);
1884		set_dev_node(dev, dev_to_node(new_parent));
1885	}
1886
1887	if (dev->class) {
1888		error = device_move_class_links(dev, old_parent, new_parent);
1889		if (error) {
1890			/* We ignore errors on cleanup since we're hosed anyway... */
1891			device_move_class_links(dev, new_parent, old_parent);
1892			if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
1893				if (new_parent)
1894					klist_remove(&dev->p->knode_parent);
1895				dev->parent = old_parent;
1896				if (old_parent) {
1897					klist_add_tail(&dev->p->knode_parent,
1898						       &old_parent->p->klist_children);
1899					set_dev_node(dev, dev_to_node(old_parent));
1900				}
1901			}
1902			cleanup_glue_dir(dev, new_parent_kobj);
1903			put_device(new_parent);
1904			goto out;
1905		}
1906	}
1907	switch (dpm_order) {
1908	case DPM_ORDER_NONE:
1909		break;
1910	case DPM_ORDER_DEV_AFTER_PARENT:
1911		device_pm_move_after(dev, new_parent);
 
1912		break;
1913	case DPM_ORDER_PARENT_BEFORE_DEV:
1914		device_pm_move_before(new_parent, dev);
 
1915		break;
1916	case DPM_ORDER_DEV_LAST:
1917		device_pm_move_last(dev);
 
1918		break;
1919	}
1920
1921	put_device(old_parent);
1922out:
1923	device_pm_unlock();
1924	put_device(dev);
1925	return error;
1926}
1927EXPORT_SYMBOL_GPL(device_move);
1928
1929/**
1930 * device_shutdown - call ->shutdown() on each device to shutdown.
1931 */
1932void device_shutdown(void)
1933{
1934	struct device *dev, *parent;
1935
1936	spin_lock(&devices_kset->list_lock);
1937	/*
1938	 * Walk the devices list backward, shutting down each in turn.
1939	 * Beware that device unplug events may also start pulling
1940	 * devices offline, even as the system is shutting down.
1941	 */
1942	while (!list_empty(&devices_kset->list)) {
1943		dev = list_entry(devices_kset->list.prev, struct device,
1944				kobj.entry);
1945
1946		/*
1947		 * hold reference count of device's parent to
1948		 * prevent it from being freed because parent's
1949		 * lock is to be held
1950		 */
1951		parent = get_device(dev->parent);
1952		get_device(dev);
1953		/*
1954		 * Make sure the device is off the kset list, in the
1955		 * event that dev->*->shutdown() doesn't remove it.
1956		 */
1957		list_del_init(&dev->kobj.entry);
1958		spin_unlock(&devices_kset->list_lock);
1959
1960		/* hold lock to avoid race with probe/release */
1961		if (parent)
1962			device_lock(parent);
1963		device_lock(dev);
1964
1965		/* Don't allow any more runtime suspends */
1966		pm_runtime_get_noresume(dev);
1967		pm_runtime_barrier(dev);
1968
 
 
 
 
 
1969		if (dev->bus && dev->bus->shutdown) {
1970			if (initcall_debug)
1971				dev_info(dev, "shutdown\n");
1972			dev->bus->shutdown(dev);
1973		} else if (dev->driver && dev->driver->shutdown) {
1974			if (initcall_debug)
1975				dev_info(dev, "shutdown\n");
1976			dev->driver->shutdown(dev);
1977		}
1978
1979		device_unlock(dev);
1980		if (parent)
1981			device_unlock(parent);
1982
1983		put_device(dev);
1984		put_device(parent);
1985
1986		spin_lock(&devices_kset->list_lock);
1987	}
1988	spin_unlock(&devices_kset->list_lock);
1989}
1990
1991/*
1992 * Device logging functions
1993 */
1994
1995#ifdef CONFIG_PRINTK
1996static int
1997create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen)
1998{
1999	const char *subsys;
2000	size_t pos = 0;
2001
2002	if (dev->class)
2003		subsys = dev->class->name;
2004	else if (dev->bus)
2005		subsys = dev->bus->name;
2006	else
2007		return 0;
2008
2009	pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys);
 
 
2010
2011	/*
2012	 * Add device identifier DEVICE=:
2013	 *   b12:8         block dev_t
2014	 *   c127:3        char dev_t
2015	 *   n8            netdev ifindex
2016	 *   +sound:card0  subsystem:devname
2017	 */
2018	if (MAJOR(dev->devt)) {
2019		char c;
2020
2021		if (strcmp(subsys, "block") == 0)
2022			c = 'b';
2023		else
2024			c = 'c';
2025		pos++;
2026		pos += snprintf(hdr + pos, hdrlen - pos,
2027				"DEVICE=%c%u:%u",
2028				c, MAJOR(dev->devt), MINOR(dev->devt));
2029	} else if (strcmp(subsys, "net") == 0) {
2030		struct net_device *net = to_net_dev(dev);
2031
2032		pos++;
2033		pos += snprintf(hdr + pos, hdrlen - pos,
2034				"DEVICE=n%u", net->ifindex);
2035	} else {
2036		pos++;
2037		pos += snprintf(hdr + pos, hdrlen - pos,
2038				"DEVICE=+%s:%s", subsys, dev_name(dev));
2039	}
2040
 
 
 
2041	return pos;
 
 
 
 
2042}
2043
2044int dev_vprintk_emit(int level, const struct device *dev,
2045		     const char *fmt, va_list args)
2046{
2047	char hdr[128];
2048	size_t hdrlen;
2049
2050	hdrlen = create_syslog_header(dev, hdr, sizeof(hdr));
2051
2052	return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen, fmt, args);
2053}
2054EXPORT_SYMBOL(dev_vprintk_emit);
2055
2056int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
2057{
2058	va_list args;
2059	int r;
2060
2061	va_start(args, fmt);
2062
2063	r = dev_vprintk_emit(level, dev, fmt, args);
2064
2065	va_end(args);
2066
2067	return r;
2068}
2069EXPORT_SYMBOL(dev_printk_emit);
2070
2071static int __dev_printk(const char *level, const struct device *dev,
2072			struct va_format *vaf)
2073{
2074	if (!dev)
2075		return printk("%s(NULL device *): %pV", level, vaf);
2076
2077	return dev_printk_emit(level[1] - '0', dev,
2078			       "%s %s: %pV",
2079			       dev_driver_string(dev), dev_name(dev), vaf);
2080}
2081
2082int dev_printk(const char *level, const struct device *dev,
2083	       const char *fmt, ...)
2084{
2085	struct va_format vaf;
2086	va_list args;
2087	int r;
2088
2089	va_start(args, fmt);
2090
2091	vaf.fmt = fmt;
2092	vaf.va = &args;
2093
2094	r = __dev_printk(level, dev, &vaf);
2095
2096	va_end(args);
2097
2098	return r;
2099}
2100EXPORT_SYMBOL(dev_printk);
2101
2102#define define_dev_printk_level(func, kern_level)		\
2103int func(const struct device *dev, const char *fmt, ...)	\
2104{								\
2105	struct va_format vaf;					\
2106	va_list args;						\
2107	int r;							\
2108								\
2109	va_start(args, fmt);					\
2110								\
2111	vaf.fmt = fmt;						\
2112	vaf.va = &args;						\
2113								\
2114	r = __dev_printk(kern_level, dev, &vaf);		\
2115								\
2116	va_end(args);						\
2117								\
2118	return r;						\
2119}								\
2120EXPORT_SYMBOL(func);
2121
2122define_dev_printk_level(dev_emerg, KERN_EMERG);
2123define_dev_printk_level(dev_alert, KERN_ALERT);
2124define_dev_printk_level(dev_crit, KERN_CRIT);
2125define_dev_printk_level(dev_err, KERN_ERR);
2126define_dev_printk_level(dev_warn, KERN_WARNING);
2127define_dev_printk_level(dev_notice, KERN_NOTICE);
2128define_dev_printk_level(_dev_info, KERN_INFO);
2129
2130#endif
v4.17
   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * drivers/base/core.c - core driver model code (device registration, etc)
   4 *
   5 * Copyright (c) 2002-3 Patrick Mochel
   6 * Copyright (c) 2002-3 Open Source Development Labs
   7 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
   8 * Copyright (c) 2006 Novell, Inc.
 
 
 
   9 */
  10
  11#include <linux/device.h>
  12#include <linux/err.h>
  13#include <linux/fwnode.h>
  14#include <linux/init.h>
  15#include <linux/module.h>
  16#include <linux/slab.h>
  17#include <linux/string.h>
  18#include <linux/kdev_t.h>
  19#include <linux/notifier.h>
  20#include <linux/of.h>
  21#include <linux/of_device.h>
  22#include <linux/genhd.h>
 
  23#include <linux/mutex.h>
  24#include <linux/pm_runtime.h>
  25#include <linux/netdevice.h>
  26#include <linux/sched/signal.h>
  27#include <linux/sysfs.h>
  28
  29#include "base.h"
  30#include "power/power.h"
  31
  32#ifdef CONFIG_SYSFS_DEPRECATED
  33#ifdef CONFIG_SYSFS_DEPRECATED_V2
  34long sysfs_deprecated = 1;
  35#else
  36long sysfs_deprecated = 0;
  37#endif
  38static int __init sysfs_deprecated_setup(char *arg)
  39{
  40	return kstrtol(arg, 10, &sysfs_deprecated);
  41}
  42early_param("sysfs.deprecated", sysfs_deprecated_setup);
  43#endif
  44
  45/* Device links support. */
  46
  47#ifdef CONFIG_SRCU
  48static DEFINE_MUTEX(device_links_lock);
  49DEFINE_STATIC_SRCU(device_links_srcu);
  50
  51static inline void device_links_write_lock(void)
  52{
  53	mutex_lock(&device_links_lock);
  54}
  55
  56static inline void device_links_write_unlock(void)
  57{
  58	mutex_unlock(&device_links_lock);
  59}
  60
  61int device_links_read_lock(void)
  62{
  63	return srcu_read_lock(&device_links_srcu);
  64}
  65
  66void device_links_read_unlock(int idx)
  67{
  68	srcu_read_unlock(&device_links_srcu, idx);
  69}
  70#else /* !CONFIG_SRCU */
  71static DECLARE_RWSEM(device_links_lock);
  72
  73static inline void device_links_write_lock(void)
  74{
  75	down_write(&device_links_lock);
  76}
  77
  78static inline void device_links_write_unlock(void)
  79{
  80	up_write(&device_links_lock);
  81}
  82
  83int device_links_read_lock(void)
  84{
  85	down_read(&device_links_lock);
  86	return 0;
  87}
  88
  89void device_links_read_unlock(int not_used)
  90{
  91	up_read(&device_links_lock);
  92}
  93#endif /* !CONFIG_SRCU */
  94
  95/**
  96 * device_is_dependent - Check if one device depends on another one
  97 * @dev: Device to check dependencies for.
  98 * @target: Device to check against.
  99 *
 100 * Check if @target depends on @dev or any device dependent on it (its child or
 101 * its consumer etc).  Return 1 if that is the case or 0 otherwise.
 102 */
 103static int device_is_dependent(struct device *dev, void *target)
 104{
 105	struct device_link *link;
 106	int ret;
 107
 108	if (WARN_ON(dev == target))
 109		return 1;
 110
 111	ret = device_for_each_child(dev, target, device_is_dependent);
 112	if (ret)
 113		return ret;
 114
 115	list_for_each_entry(link, &dev->links.consumers, s_node) {
 116		if (WARN_ON(link->consumer == target))
 117			return 1;
 118
 119		ret = device_is_dependent(link->consumer, target);
 120		if (ret)
 121			break;
 122	}
 123	return ret;
 124}
 125
 126static int device_reorder_to_tail(struct device *dev, void *not_used)
 127{
 128	struct device_link *link;
 129
 130	/*
 131	 * Devices that have not been registered yet will be put to the ends
 132	 * of the lists during the registration, so skip them here.
 133	 */
 134	if (device_is_registered(dev))
 135		devices_kset_move_last(dev);
 136
 137	if (device_pm_initialized(dev))
 138		device_pm_move_last(dev);
 139
 140	device_for_each_child(dev, NULL, device_reorder_to_tail);
 141	list_for_each_entry(link, &dev->links.consumers, s_node)
 142		device_reorder_to_tail(link->consumer, NULL);
 143
 144	return 0;
 145}
 146
 147/**
 148 * device_link_add - Create a link between two devices.
 149 * @consumer: Consumer end of the link.
 150 * @supplier: Supplier end of the link.
 151 * @flags: Link flags.
 152 *
 153 * The caller is responsible for the proper synchronization of the link creation
 154 * with runtime PM.  First, setting the DL_FLAG_PM_RUNTIME flag will cause the
 155 * runtime PM framework to take the link into account.  Second, if the
 156 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
 157 * be forced into the active metastate and reference-counted upon the creation
 158 * of the link.  If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
 159 * ignored.
 160 *
 161 * If the DL_FLAG_AUTOREMOVE is set, the link will be removed automatically
 162 * when the consumer device driver unbinds from it.  The combination of both
 163 * DL_FLAG_AUTOREMOVE and DL_FLAG_STATELESS set is invalid and will cause NULL
 164 * to be returned.
 165 *
 166 * A side effect of the link creation is re-ordering of dpm_list and the
 167 * devices_kset list by moving the consumer device and all devices depending
 168 * on it to the ends of these lists (that does not happen to devices that have
 169 * not been registered when this function is called).
 170 *
 171 * The supplier device is required to be registered when this function is called
 172 * and NULL will be returned if that is not the case.  The consumer device need
 173 * not be registered, however.
 174 */
 175struct device_link *device_link_add(struct device *consumer,
 176				    struct device *supplier, u32 flags)
 177{
 178	struct device_link *link;
 179
 180	if (!consumer || !supplier ||
 181	    ((flags & DL_FLAG_STATELESS) && (flags & DL_FLAG_AUTOREMOVE)))
 182		return NULL;
 183
 184	device_links_write_lock();
 185	device_pm_lock();
 186
 187	/*
 188	 * If the supplier has not been fully registered yet or there is a
 189	 * reverse dependency between the consumer and the supplier already in
 190	 * the graph, return NULL.
 191	 */
 192	if (!device_pm_initialized(supplier)
 193	    || device_is_dependent(consumer, supplier)) {
 194		link = NULL;
 195		goto out;
 196	}
 197
 198	list_for_each_entry(link, &supplier->links.consumers, s_node)
 199		if (link->consumer == consumer) {
 200			kref_get(&link->kref);
 201			goto out;
 202		}
 203
 204	link = kzalloc(sizeof(*link), GFP_KERNEL);
 205	if (!link)
 206		goto out;
 207
 208	if (flags & DL_FLAG_PM_RUNTIME) {
 209		if (flags & DL_FLAG_RPM_ACTIVE) {
 210			if (pm_runtime_get_sync(supplier) < 0) {
 211				pm_runtime_put_noidle(supplier);
 212				kfree(link);
 213				link = NULL;
 214				goto out;
 215			}
 216			link->rpm_active = true;
 217		}
 218		pm_runtime_new_link(consumer);
 219	}
 220	get_device(supplier);
 221	link->supplier = supplier;
 222	INIT_LIST_HEAD(&link->s_node);
 223	get_device(consumer);
 224	link->consumer = consumer;
 225	INIT_LIST_HEAD(&link->c_node);
 226	link->flags = flags;
 227	kref_init(&link->kref);
 228
 229	/* Determine the initial link state. */
 230	if (flags & DL_FLAG_STATELESS) {
 231		link->status = DL_STATE_NONE;
 232	} else {
 233		switch (supplier->links.status) {
 234		case DL_DEV_DRIVER_BOUND:
 235			switch (consumer->links.status) {
 236			case DL_DEV_PROBING:
 237				/*
 238				 * Balance the decrementation of the supplier's
 239				 * runtime PM usage counter after consumer probe
 240				 * in driver_probe_device().
 241				 */
 242				if (flags & DL_FLAG_PM_RUNTIME)
 243					pm_runtime_get_sync(supplier);
 244
 245				link->status = DL_STATE_CONSUMER_PROBE;
 246				break;
 247			case DL_DEV_DRIVER_BOUND:
 248				link->status = DL_STATE_ACTIVE;
 249				break;
 250			default:
 251				link->status = DL_STATE_AVAILABLE;
 252				break;
 253			}
 254			break;
 255		case DL_DEV_UNBINDING:
 256			link->status = DL_STATE_SUPPLIER_UNBIND;
 257			break;
 258		default:
 259			link->status = DL_STATE_DORMANT;
 260			break;
 261		}
 262	}
 263
 264	/*
 265	 * Move the consumer and all of the devices depending on it to the end
 266	 * of dpm_list and the devices_kset list.
 267	 *
 268	 * It is necessary to hold dpm_list locked throughout all that or else
 269	 * we may end up suspending with a wrong ordering of it.
 270	 */
 271	device_reorder_to_tail(consumer, NULL);
 272
 273	list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
 274	list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
 275
 276	dev_info(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
 277
 278 out:
 279	device_pm_unlock();
 280	device_links_write_unlock();
 281	return link;
 282}
 283EXPORT_SYMBOL_GPL(device_link_add);
 284
 285static void device_link_free(struct device_link *link)
 286{
 287	put_device(link->consumer);
 288	put_device(link->supplier);
 289	kfree(link);
 290}
 291
 292#ifdef CONFIG_SRCU
 293static void __device_link_free_srcu(struct rcu_head *rhead)
 294{
 295	device_link_free(container_of(rhead, struct device_link, rcu_head));
 296}
 297
 298static void __device_link_del(struct kref *kref)
 299{
 300	struct device_link *link = container_of(kref, struct device_link, kref);
 301
 302	dev_info(link->consumer, "Dropping the link to %s\n",
 303		 dev_name(link->supplier));
 304
 305	if (link->flags & DL_FLAG_PM_RUNTIME)
 306		pm_runtime_drop_link(link->consumer);
 307
 308	list_del_rcu(&link->s_node);
 309	list_del_rcu(&link->c_node);
 310	call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
 311}
 312#else /* !CONFIG_SRCU */
 313static void __device_link_del(struct kref *kref)
 314{
 315	struct device_link *link = container_of(kref, struct device_link, kref);
 316
 317	dev_info(link->consumer, "Dropping the link to %s\n",
 318		 dev_name(link->supplier));
 319
 320	if (link->flags & DL_FLAG_PM_RUNTIME)
 321		pm_runtime_drop_link(link->consumer);
 322
 323	list_del(&link->s_node);
 324	list_del(&link->c_node);
 325	device_link_free(link);
 326}
 327#endif /* !CONFIG_SRCU */
 328
 329/**
 330 * device_link_del - Delete a link between two devices.
 331 * @link: Device link to delete.
 332 *
 333 * The caller must ensure proper synchronization of this function with runtime
 334 * PM.  If the link was added multiple times, it needs to be deleted as often.
 335 * Care is required for hotplugged devices:  Their links are purged on removal
 336 * and calling device_link_del() is then no longer allowed.
 337 */
 338void device_link_del(struct device_link *link)
 339{
 340	device_links_write_lock();
 341	device_pm_lock();
 342	kref_put(&link->kref, __device_link_del);
 343	device_pm_unlock();
 344	device_links_write_unlock();
 345}
 346EXPORT_SYMBOL_GPL(device_link_del);
 347
 348static void device_links_missing_supplier(struct device *dev)
 349{
 350	struct device_link *link;
 351
 352	list_for_each_entry(link, &dev->links.suppliers, c_node)
 353		if (link->status == DL_STATE_CONSUMER_PROBE)
 354			WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
 355}
 356
 357/**
 358 * device_links_check_suppliers - Check presence of supplier drivers.
 359 * @dev: Consumer device.
 360 *
 361 * Check links from this device to any suppliers.  Walk the list of the device's
 362 * links to suppliers and see if all of them are available.  If not, simply
 363 * return -EPROBE_DEFER.
 364 *
 365 * We need to guarantee that the supplier will not go away after the check has
 366 * been positive here.  It only can go away in __device_release_driver() and
 367 * that function  checks the device's links to consumers.  This means we need to
 368 * mark the link as "consumer probe in progress" to make the supplier removal
 369 * wait for us to complete (or bad things may happen).
 370 *
 371 * Links with the DL_FLAG_STATELESS flag set are ignored.
 372 */
 373int device_links_check_suppliers(struct device *dev)
 374{
 375	struct device_link *link;
 376	int ret = 0;
 377
 378	device_links_write_lock();
 379
 380	list_for_each_entry(link, &dev->links.suppliers, c_node) {
 381		if (link->flags & DL_FLAG_STATELESS)
 382			continue;
 383
 384		if (link->status != DL_STATE_AVAILABLE) {
 385			device_links_missing_supplier(dev);
 386			ret = -EPROBE_DEFER;
 387			break;
 388		}
 389		WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
 390	}
 391	dev->links.status = DL_DEV_PROBING;
 392
 393	device_links_write_unlock();
 394	return ret;
 395}
 396
 397/**
 398 * device_links_driver_bound - Update device links after probing its driver.
 399 * @dev: Device to update the links for.
 400 *
 401 * The probe has been successful, so update links from this device to any
 402 * consumers by changing their status to "available".
 403 *
 404 * Also change the status of @dev's links to suppliers to "active".
 405 *
 406 * Links with the DL_FLAG_STATELESS flag set are ignored.
 407 */
 408void device_links_driver_bound(struct device *dev)
 409{
 410	struct device_link *link;
 411
 412	device_links_write_lock();
 413
 414	list_for_each_entry(link, &dev->links.consumers, s_node) {
 415		if (link->flags & DL_FLAG_STATELESS)
 416			continue;
 417
 418		WARN_ON(link->status != DL_STATE_DORMANT);
 419		WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
 420	}
 421
 422	list_for_each_entry(link, &dev->links.suppliers, c_node) {
 423		if (link->flags & DL_FLAG_STATELESS)
 424			continue;
 425
 426		WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
 427		WRITE_ONCE(link->status, DL_STATE_ACTIVE);
 428	}
 429
 430	dev->links.status = DL_DEV_DRIVER_BOUND;
 431
 432	device_links_write_unlock();
 433}
 434
 435/**
 436 * __device_links_no_driver - Update links of a device without a driver.
 437 * @dev: Device without a drvier.
 438 *
 439 * Delete all non-persistent links from this device to any suppliers.
 440 *
 441 * Persistent links stay around, but their status is changed to "available",
 442 * unless they already are in the "supplier unbind in progress" state in which
 443 * case they need not be updated.
 444 *
 445 * Links with the DL_FLAG_STATELESS flag set are ignored.
 446 */
 447static void __device_links_no_driver(struct device *dev)
 448{
 449	struct device_link *link, *ln;
 450
 451	list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
 452		if (link->flags & DL_FLAG_STATELESS)
 453			continue;
 454
 455		if (link->flags & DL_FLAG_AUTOREMOVE)
 456			kref_put(&link->kref, __device_link_del);
 457		else if (link->status != DL_STATE_SUPPLIER_UNBIND)
 458			WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
 459	}
 460
 461	dev->links.status = DL_DEV_NO_DRIVER;
 462}
 463
 464void device_links_no_driver(struct device *dev)
 465{
 466	device_links_write_lock();
 467	__device_links_no_driver(dev);
 468	device_links_write_unlock();
 469}
 470
 471/**
 472 * device_links_driver_cleanup - Update links after driver removal.
 473 * @dev: Device whose driver has just gone away.
 474 *
 475 * Update links to consumers for @dev by changing their status to "dormant" and
 476 * invoke %__device_links_no_driver() to update links to suppliers for it as
 477 * appropriate.
 478 *
 479 * Links with the DL_FLAG_STATELESS flag set are ignored.
 480 */
 481void device_links_driver_cleanup(struct device *dev)
 482{
 483	struct device_link *link;
 484
 485	device_links_write_lock();
 486
 487	list_for_each_entry(link, &dev->links.consumers, s_node) {
 488		if (link->flags & DL_FLAG_STATELESS)
 489			continue;
 490
 491		WARN_ON(link->flags & DL_FLAG_AUTOREMOVE);
 492		WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
 493		WRITE_ONCE(link->status, DL_STATE_DORMANT);
 494	}
 495
 496	__device_links_no_driver(dev);
 497
 498	device_links_write_unlock();
 499}
 500
 501/**
 502 * device_links_busy - Check if there are any busy links to consumers.
 503 * @dev: Device to check.
 504 *
 505 * Check each consumer of the device and return 'true' if its link's status
 506 * is one of "consumer probe" or "active" (meaning that the given consumer is
 507 * probing right now or its driver is present).  Otherwise, change the link
 508 * state to "supplier unbind" to prevent the consumer from being probed
 509 * successfully going forward.
 510 *
 511 * Return 'false' if there are no probing or active consumers.
 512 *
 513 * Links with the DL_FLAG_STATELESS flag set are ignored.
 514 */
 515bool device_links_busy(struct device *dev)
 516{
 517	struct device_link *link;
 518	bool ret = false;
 519
 520	device_links_write_lock();
 521
 522	list_for_each_entry(link, &dev->links.consumers, s_node) {
 523		if (link->flags & DL_FLAG_STATELESS)
 524			continue;
 525
 526		if (link->status == DL_STATE_CONSUMER_PROBE
 527		    || link->status == DL_STATE_ACTIVE) {
 528			ret = true;
 529			break;
 530		}
 531		WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
 532	}
 533
 534	dev->links.status = DL_DEV_UNBINDING;
 535
 536	device_links_write_unlock();
 537	return ret;
 538}
 539
 540/**
 541 * device_links_unbind_consumers - Force unbind consumers of the given device.
 542 * @dev: Device to unbind the consumers of.
 543 *
 544 * Walk the list of links to consumers for @dev and if any of them is in the
 545 * "consumer probe" state, wait for all device probes in progress to complete
 546 * and start over.
 547 *
 548 * If that's not the case, change the status of the link to "supplier unbind"
 549 * and check if the link was in the "active" state.  If so, force the consumer
 550 * driver to unbind and start over (the consumer will not re-probe as we have
 551 * changed the state of the link already).
 552 *
 553 * Links with the DL_FLAG_STATELESS flag set are ignored.
 554 */
 555void device_links_unbind_consumers(struct device *dev)
 556{
 557	struct device_link *link;
 558
 559 start:
 560	device_links_write_lock();
 561
 562	list_for_each_entry(link, &dev->links.consumers, s_node) {
 563		enum device_link_state status;
 564
 565		if (link->flags & DL_FLAG_STATELESS)
 566			continue;
 567
 568		status = link->status;
 569		if (status == DL_STATE_CONSUMER_PROBE) {
 570			device_links_write_unlock();
 571
 572			wait_for_device_probe();
 573			goto start;
 574		}
 575		WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
 576		if (status == DL_STATE_ACTIVE) {
 577			struct device *consumer = link->consumer;
 578
 579			get_device(consumer);
 580
 581			device_links_write_unlock();
 582
 583			device_release_driver_internal(consumer, NULL,
 584						       consumer->parent);
 585			put_device(consumer);
 586			goto start;
 587		}
 588	}
 589
 590	device_links_write_unlock();
 591}
 592
 593/**
 594 * device_links_purge - Delete existing links to other devices.
 595 * @dev: Target device.
 596 */
 597static void device_links_purge(struct device *dev)
 598{
 599	struct device_link *link, *ln;
 600
 601	/*
 602	 * Delete all of the remaining links from this device to any other
 603	 * devices (either consumers or suppliers).
 604	 */
 605	device_links_write_lock();
 606
 607	list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
 608		WARN_ON(link->status == DL_STATE_ACTIVE);
 609		__device_link_del(&link->kref);
 610	}
 611
 612	list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
 613		WARN_ON(link->status != DL_STATE_DORMANT &&
 614			link->status != DL_STATE_NONE);
 615		__device_link_del(&link->kref);
 616	}
 617
 618	device_links_write_unlock();
 619}
 620
 621/* Device links support end. */
 622
 623int (*platform_notify)(struct device *dev) = NULL;
 624int (*platform_notify_remove)(struct device *dev) = NULL;
 625static struct kobject *dev_kobj;
 626struct kobject *sysfs_dev_char_kobj;
 627struct kobject *sysfs_dev_block_kobj;
 628
 629static DEFINE_MUTEX(device_hotplug_lock);
 630
 631void lock_device_hotplug(void)
 632{
 633	mutex_lock(&device_hotplug_lock);
 634}
 635
 636void unlock_device_hotplug(void)
 637{
 638	mutex_unlock(&device_hotplug_lock);
 639}
 640
 641int lock_device_hotplug_sysfs(void)
 642{
 643	if (mutex_trylock(&device_hotplug_lock))
 644		return 0;
 645
 646	/* Avoid busy looping (5 ms of sleep should do). */
 647	msleep(5);
 648	return restart_syscall();
 649}
 650
 651#ifdef CONFIG_BLOCK
 652static inline int device_is_not_partition(struct device *dev)
 653{
 654	return !(dev->type == &part_type);
 655}
 656#else
 657static inline int device_is_not_partition(struct device *dev)
 658{
 659	return 1;
 660}
 661#endif
 662
 663/**
 664 * dev_driver_string - Return a device's driver name, if at all possible
 665 * @dev: struct device to get the name of
 666 *
 667 * Will return the device's driver's name if it is bound to a device.  If
 668 * the device is not bound to a driver, it will return the name of the bus
 669 * it is attached to.  If it is not attached to a bus either, an empty
 670 * string will be returned.
 671 */
 672const char *dev_driver_string(const struct device *dev)
 673{
 674	struct device_driver *drv;
 675
 676	/* dev->driver can change to NULL underneath us because of unbinding,
 677	 * so be careful about accessing it.  dev->bus and dev->class should
 678	 * never change once they are set, so they don't need special care.
 679	 */
 680	drv = READ_ONCE(dev->driver);
 681	return drv ? drv->name :
 682			(dev->bus ? dev->bus->name :
 683			(dev->class ? dev->class->name : ""));
 684}
 685EXPORT_SYMBOL(dev_driver_string);
 686
 687#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
 688
 689static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
 690			     char *buf)
 691{
 692	struct device_attribute *dev_attr = to_dev_attr(attr);
 693	struct device *dev = kobj_to_dev(kobj);
 694	ssize_t ret = -EIO;
 695
 696	if (dev_attr->show)
 697		ret = dev_attr->show(dev, dev_attr, buf);
 698	if (ret >= (ssize_t)PAGE_SIZE) {
 699		printk("dev_attr_show: %pS returned bad count\n",
 700				dev_attr->show);
 701	}
 702	return ret;
 703}
 704
 705static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
 706			      const char *buf, size_t count)
 707{
 708	struct device_attribute *dev_attr = to_dev_attr(attr);
 709	struct device *dev = kobj_to_dev(kobj);
 710	ssize_t ret = -EIO;
 711
 712	if (dev_attr->store)
 713		ret = dev_attr->store(dev, dev_attr, buf, count);
 714	return ret;
 715}
 716
 717static const struct sysfs_ops dev_sysfs_ops = {
 718	.show	= dev_attr_show,
 719	.store	= dev_attr_store,
 720};
 721
 722#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
 723
 724ssize_t device_store_ulong(struct device *dev,
 725			   struct device_attribute *attr,
 726			   const char *buf, size_t size)
 727{
 728	struct dev_ext_attribute *ea = to_ext_attr(attr);
 729	char *end;
 730	unsigned long new = simple_strtoul(buf, &end, 0);
 731	if (end == buf)
 732		return -EINVAL;
 733	*(unsigned long *)(ea->var) = new;
 734	/* Always return full write size even if we didn't consume all */
 735	return size;
 736}
 737EXPORT_SYMBOL_GPL(device_store_ulong);
 738
 739ssize_t device_show_ulong(struct device *dev,
 740			  struct device_attribute *attr,
 741			  char *buf)
 742{
 743	struct dev_ext_attribute *ea = to_ext_attr(attr);
 744	return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
 745}
 746EXPORT_SYMBOL_GPL(device_show_ulong);
 747
 748ssize_t device_store_int(struct device *dev,
 749			 struct device_attribute *attr,
 750			 const char *buf, size_t size)
 751{
 752	struct dev_ext_attribute *ea = to_ext_attr(attr);
 753	char *end;
 754	long new = simple_strtol(buf, &end, 0);
 755	if (end == buf || new > INT_MAX || new < INT_MIN)
 756		return -EINVAL;
 757	*(int *)(ea->var) = new;
 758	/* Always return full write size even if we didn't consume all */
 759	return size;
 760}
 761EXPORT_SYMBOL_GPL(device_store_int);
 762
 763ssize_t device_show_int(struct device *dev,
 764			struct device_attribute *attr,
 765			char *buf)
 766{
 767	struct dev_ext_attribute *ea = to_ext_attr(attr);
 768
 769	return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
 770}
 771EXPORT_SYMBOL_GPL(device_show_int);
 772
 773ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
 774			  const char *buf, size_t size)
 775{
 776	struct dev_ext_attribute *ea = to_ext_attr(attr);
 777
 778	if (strtobool(buf, ea->var) < 0)
 779		return -EINVAL;
 780
 781	return size;
 782}
 783EXPORT_SYMBOL_GPL(device_store_bool);
 784
 785ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
 786			 char *buf)
 787{
 788	struct dev_ext_attribute *ea = to_ext_attr(attr);
 789
 790	return snprintf(buf, PAGE_SIZE, "%d\n", *(bool *)(ea->var));
 791}
 792EXPORT_SYMBOL_GPL(device_show_bool);
 793
 794/**
 795 * device_release - free device structure.
 796 * @kobj: device's kobject.
 797 *
 798 * This is called once the reference count for the object
 799 * reaches 0. We forward the call to the device's release
 800 * method, which should handle actually freeing the structure.
 801 */
 802static void device_release(struct kobject *kobj)
 803{
 804	struct device *dev = kobj_to_dev(kobj);
 805	struct device_private *p = dev->p;
 806
 807	/*
 808	 * Some platform devices are driven without driver attached
 809	 * and managed resources may have been acquired.  Make sure
 810	 * all resources are released.
 811	 *
 812	 * Drivers still can add resources into device after device
 813	 * is deleted but alive, so release devres here to avoid
 814	 * possible memory leak.
 815	 */
 816	devres_release_all(dev);
 817
 818	if (dev->release)
 819		dev->release(dev);
 820	else if (dev->type && dev->type->release)
 821		dev->type->release(dev);
 822	else if (dev->class && dev->class->dev_release)
 823		dev->class->dev_release(dev);
 824	else
 825		WARN(1, KERN_ERR "Device '%s' does not have a release() "
 826			"function, it is broken and must be fixed.\n",
 827			dev_name(dev));
 828	kfree(p);
 829}
 830
 831static const void *device_namespace(struct kobject *kobj)
 832{
 833	struct device *dev = kobj_to_dev(kobj);
 834	const void *ns = NULL;
 835
 836	if (dev->class && dev->class->ns_type)
 837		ns = dev->class->namespace(dev);
 838
 839	return ns;
 840}
 841
 842static struct kobj_type device_ktype = {
 843	.release	= device_release,
 844	.sysfs_ops	= &dev_sysfs_ops,
 845	.namespace	= device_namespace,
 846};
 847
 848
 849static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
 850{
 851	struct kobj_type *ktype = get_ktype(kobj);
 852
 853	if (ktype == &device_ktype) {
 854		struct device *dev = kobj_to_dev(kobj);
 855		if (dev->bus)
 856			return 1;
 857		if (dev->class)
 858			return 1;
 859	}
 860	return 0;
 861}
 862
 863static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
 864{
 865	struct device *dev = kobj_to_dev(kobj);
 866
 867	if (dev->bus)
 868		return dev->bus->name;
 869	if (dev->class)
 870		return dev->class->name;
 871	return NULL;
 872}
 873
 874static int dev_uevent(struct kset *kset, struct kobject *kobj,
 875		      struct kobj_uevent_env *env)
 876{
 877	struct device *dev = kobj_to_dev(kobj);
 878	int retval = 0;
 879
 880	/* add device node properties if present */
 881	if (MAJOR(dev->devt)) {
 882		const char *tmp;
 883		const char *name;
 884		umode_t mode = 0;
 885		kuid_t uid = GLOBAL_ROOT_UID;
 886		kgid_t gid = GLOBAL_ROOT_GID;
 887
 888		add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
 889		add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
 890		name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
 891		if (name) {
 892			add_uevent_var(env, "DEVNAME=%s", name);
 893			if (mode)
 894				add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
 895			if (!uid_eq(uid, GLOBAL_ROOT_UID))
 896				add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
 897			if (!gid_eq(gid, GLOBAL_ROOT_GID))
 898				add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
 899			kfree(tmp);
 900		}
 901	}
 902
 903	if (dev->type && dev->type->name)
 904		add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
 905
 906	if (dev->driver)
 907		add_uevent_var(env, "DRIVER=%s", dev->driver->name);
 908
 909	/* Add common DT information about the device */
 910	of_device_uevent(dev, env);
 911
 912	/* have the bus specific function add its stuff */
 913	if (dev->bus && dev->bus->uevent) {
 914		retval = dev->bus->uevent(dev, env);
 915		if (retval)
 916			pr_debug("device: '%s': %s: bus uevent() returned %d\n",
 917				 dev_name(dev), __func__, retval);
 918	}
 919
 920	/* have the class specific function add its stuff */
 921	if (dev->class && dev->class->dev_uevent) {
 922		retval = dev->class->dev_uevent(dev, env);
 923		if (retval)
 924			pr_debug("device: '%s': %s: class uevent() "
 925				 "returned %d\n", dev_name(dev),
 926				 __func__, retval);
 927	}
 928
 929	/* have the device type specific function add its stuff */
 930	if (dev->type && dev->type->uevent) {
 931		retval = dev->type->uevent(dev, env);
 932		if (retval)
 933			pr_debug("device: '%s': %s: dev_type uevent() "
 934				 "returned %d\n", dev_name(dev),
 935				 __func__, retval);
 936	}
 937
 938	return retval;
 939}
 940
 941static const struct kset_uevent_ops device_uevent_ops = {
 942	.filter =	dev_uevent_filter,
 943	.name =		dev_uevent_name,
 944	.uevent =	dev_uevent,
 945};
 946
 947static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
 948			   char *buf)
 949{
 950	struct kobject *top_kobj;
 951	struct kset *kset;
 952	struct kobj_uevent_env *env = NULL;
 953	int i;
 954	size_t count = 0;
 955	int retval;
 956
 957	/* search the kset, the device belongs to */
 958	top_kobj = &dev->kobj;
 959	while (!top_kobj->kset && top_kobj->parent)
 960		top_kobj = top_kobj->parent;
 961	if (!top_kobj->kset)
 962		goto out;
 963
 964	kset = top_kobj->kset;
 965	if (!kset->uevent_ops || !kset->uevent_ops->uevent)
 966		goto out;
 967
 968	/* respect filter */
 969	if (kset->uevent_ops && kset->uevent_ops->filter)
 970		if (!kset->uevent_ops->filter(kset, &dev->kobj))
 971			goto out;
 972
 973	env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
 974	if (!env)
 975		return -ENOMEM;
 976
 977	/* let the kset specific function add its keys */
 978	retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
 979	if (retval)
 980		goto out;
 981
 982	/* copy keys to file */
 983	for (i = 0; i < env->envp_idx; i++)
 984		count += sprintf(&buf[count], "%s\n", env->envp[i]);
 985out:
 986	kfree(env);
 987	return count;
 988}
 989
 990static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
 991			    const char *buf, size_t count)
 992{
 993	if (kobject_synth_uevent(&dev->kobj, buf, count))
 994		dev_err(dev, "uevent: failed to send synthetic uevent\n");
 995
 
 
 
 
 996	return count;
 997}
 998static DEVICE_ATTR_RW(uevent);
 999
1000static ssize_t online_show(struct device *dev, struct device_attribute *attr,
1001			   char *buf)
1002{
1003	bool val;
1004
1005	device_lock(dev);
1006	val = !dev->offline;
1007	device_unlock(dev);
1008	return sprintf(buf, "%u\n", val);
1009}
1010
1011static ssize_t online_store(struct device *dev, struct device_attribute *attr,
1012			    const char *buf, size_t count)
1013{
1014	bool val;
1015	int ret;
1016
1017	ret = strtobool(buf, &val);
1018	if (ret < 0)
1019		return ret;
1020
1021	ret = lock_device_hotplug_sysfs();
1022	if (ret)
1023		return ret;
1024
1025	ret = val ? device_online(dev) : device_offline(dev);
1026	unlock_device_hotplug();
1027	return ret < 0 ? ret : count;
1028}
1029static DEVICE_ATTR_RW(online);
1030
1031int device_add_groups(struct device *dev, const struct attribute_group **groups)
1032{
1033	return sysfs_create_groups(&dev->kobj, groups);
1034}
1035EXPORT_SYMBOL_GPL(device_add_groups);
1036
1037void device_remove_groups(struct device *dev,
1038			  const struct attribute_group **groups)
1039{
1040	sysfs_remove_groups(&dev->kobj, groups);
1041}
1042EXPORT_SYMBOL_GPL(device_remove_groups);
1043
1044union device_attr_group_devres {
1045	const struct attribute_group *group;
1046	const struct attribute_group **groups;
1047};
1048
1049static int devm_attr_group_match(struct device *dev, void *res, void *data)
1050{
1051	return ((union device_attr_group_devres *)res)->group == data;
1052}
1053
1054static void devm_attr_group_remove(struct device *dev, void *res)
1055{
1056	union device_attr_group_devres *devres = res;
1057	const struct attribute_group *group = devres->group;
1058
1059	dev_dbg(dev, "%s: removing group %p\n", __func__, group);
1060	sysfs_remove_group(&dev->kobj, group);
1061}
1062
1063static void devm_attr_groups_remove(struct device *dev, void *res)
1064{
1065	union device_attr_group_devres *devres = res;
1066	const struct attribute_group **groups = devres->groups;
1067
1068	dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
1069	sysfs_remove_groups(&dev->kobj, groups);
1070}
1071
1072/**
1073 * devm_device_add_group - given a device, create a managed attribute group
1074 * @dev:	The device to create the group for
1075 * @grp:	The attribute group to create
1076 *
1077 * This function creates a group for the first time.  It will explicitly
1078 * warn and error if any of the attribute files being created already exist.
1079 *
1080 * Returns 0 on success or error code on failure.
1081 */
1082int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
1083{
1084	union device_attr_group_devres *devres;
1085	int error;
1086
1087	devres = devres_alloc(devm_attr_group_remove,
1088			      sizeof(*devres), GFP_KERNEL);
1089	if (!devres)
1090		return -ENOMEM;
1091
1092	error = sysfs_create_group(&dev->kobj, grp);
1093	if (error) {
1094		devres_free(devres);
1095		return error;
1096	}
1097
1098	devres->group = grp;
1099	devres_add(dev, devres);
1100	return 0;
1101}
1102EXPORT_SYMBOL_GPL(devm_device_add_group);
1103
1104/**
1105 * devm_device_remove_group: remove a managed group from a device
1106 * @dev:	device to remove the group from
1107 * @grp:	group to remove
1108 *
1109 * This function removes a group of attributes from a device. The attributes
1110 * previously have to have been created for this group, otherwise it will fail.
1111 */
1112void devm_device_remove_group(struct device *dev,
1113			      const struct attribute_group *grp)
1114{
1115	WARN_ON(devres_release(dev, devm_attr_group_remove,
1116			       devm_attr_group_match,
1117			       /* cast away const */ (void *)grp));
1118}
1119EXPORT_SYMBOL_GPL(devm_device_remove_group);
1120
1121/**
1122 * devm_device_add_groups - create a bunch of managed attribute groups
1123 * @dev:	The device to create the group for
1124 * @groups:	The attribute groups to create, NULL terminated
1125 *
1126 * This function creates a bunch of managed attribute groups.  If an error
1127 * occurs when creating a group, all previously created groups will be
1128 * removed, unwinding everything back to the original state when this
1129 * function was called.  It will explicitly warn and error if any of the
1130 * attribute files being created already exist.
1131 *
1132 * Returns 0 on success or error code from sysfs_create_group on failure.
1133 */
1134int devm_device_add_groups(struct device *dev,
1135			   const struct attribute_group **groups)
1136{
1137	union device_attr_group_devres *devres;
1138	int error;
1139
1140	devres = devres_alloc(devm_attr_groups_remove,
1141			      sizeof(*devres), GFP_KERNEL);
1142	if (!devres)
1143		return -ENOMEM;
1144
1145	error = sysfs_create_groups(&dev->kobj, groups);
1146	if (error) {
1147		devres_free(devres);
1148		return error;
1149	}
1150
1151	devres->groups = groups;
1152	devres_add(dev, devres);
1153	return 0;
1154}
1155EXPORT_SYMBOL_GPL(devm_device_add_groups);
1156
1157/**
1158 * devm_device_remove_groups - remove a list of managed groups
1159 *
1160 * @dev:	The device for the groups to be removed from
1161 * @groups:	NULL terminated list of groups to be removed
1162 *
1163 * If groups is not NULL, remove the specified groups from the device.
1164 */
1165void devm_device_remove_groups(struct device *dev,
1166			       const struct attribute_group **groups)
1167{
1168	WARN_ON(devres_release(dev, devm_attr_groups_remove,
1169			       devm_attr_group_match,
1170			       /* cast away const */ (void *)groups));
1171}
1172EXPORT_SYMBOL_GPL(devm_device_remove_groups);
1173
1174static int device_add_attrs(struct device *dev)
1175{
1176	struct class *class = dev->class;
1177	const struct device_type *type = dev->type;
1178	int error;
1179
1180	if (class) {
1181		error = device_add_groups(dev, class->dev_groups);
1182		if (error)
1183			return error;
1184	}
1185
1186	if (type) {
1187		error = device_add_groups(dev, type->groups);
1188		if (error)
1189			goto err_remove_class_groups;
1190	}
1191
1192	error = device_add_groups(dev, dev->groups);
1193	if (error)
1194		goto err_remove_type_groups;
1195
1196	if (device_supports_offline(dev) && !dev->offline_disabled) {
1197		error = device_create_file(dev, &dev_attr_online);
1198		if (error)
1199			goto err_remove_dev_groups;
1200	}
1201
1202	return 0;
1203
1204 err_remove_dev_groups:
1205	device_remove_groups(dev, dev->groups);
1206 err_remove_type_groups:
1207	if (type)
1208		device_remove_groups(dev, type->groups);
1209 err_remove_class_groups:
1210	if (class)
1211		device_remove_groups(dev, class->dev_groups);
1212
1213	return error;
1214}
1215
1216static void device_remove_attrs(struct device *dev)
1217{
1218	struct class *class = dev->class;
1219	const struct device_type *type = dev->type;
1220
1221	device_remove_file(dev, &dev_attr_online);
1222	device_remove_groups(dev, dev->groups);
1223
1224	if (type)
1225		device_remove_groups(dev, type->groups);
1226
1227	if (class)
1228		device_remove_groups(dev, class->dev_groups);
1229}
1230
1231static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
1232			char *buf)
1233{
1234	return print_dev_t(buf, dev->devt);
1235}
1236static DEVICE_ATTR_RO(dev);
1237
1238/* /sys/devices/ */
1239struct kset *devices_kset;
1240
1241/**
1242 * devices_kset_move_before - Move device in the devices_kset's list.
1243 * @deva: Device to move.
1244 * @devb: Device @deva should come before.
1245 */
1246static void devices_kset_move_before(struct device *deva, struct device *devb)
1247{
1248	if (!devices_kset)
1249		return;
1250	pr_debug("devices_kset: Moving %s before %s\n",
1251		 dev_name(deva), dev_name(devb));
1252	spin_lock(&devices_kset->list_lock);
1253	list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
1254	spin_unlock(&devices_kset->list_lock);
1255}
1256
1257/**
1258 * devices_kset_move_after - Move device in the devices_kset's list.
1259 * @deva: Device to move
1260 * @devb: Device @deva should come after.
1261 */
1262static void devices_kset_move_after(struct device *deva, struct device *devb)
1263{
1264	if (!devices_kset)
1265		return;
1266	pr_debug("devices_kset: Moving %s after %s\n",
1267		 dev_name(deva), dev_name(devb));
1268	spin_lock(&devices_kset->list_lock);
1269	list_move(&deva->kobj.entry, &devb->kobj.entry);
1270	spin_unlock(&devices_kset->list_lock);
1271}
1272
1273/**
1274 * devices_kset_move_last - move the device to the end of devices_kset's list.
1275 * @dev: device to move
1276 */
1277void devices_kset_move_last(struct device *dev)
1278{
1279	if (!devices_kset)
1280		return;
1281	pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
1282	spin_lock(&devices_kset->list_lock);
1283	list_move_tail(&dev->kobj.entry, &devices_kset->list);
1284	spin_unlock(&devices_kset->list_lock);
1285}
1286
1287/**
1288 * device_create_file - create sysfs attribute file for device.
1289 * @dev: device.
1290 * @attr: device attribute descriptor.
1291 */
1292int device_create_file(struct device *dev,
1293		       const struct device_attribute *attr)
1294{
1295	int error = 0;
1296
1297	if (dev) {
1298		WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
1299			"Attribute %s: write permission without 'store'\n",
1300			attr->attr.name);
1301		WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
1302			"Attribute %s: read permission without 'show'\n",
1303			attr->attr.name);
1304		error = sysfs_create_file(&dev->kobj, &attr->attr);
1305	}
1306
1307	return error;
1308}
1309EXPORT_SYMBOL_GPL(device_create_file);
1310
1311/**
1312 * device_remove_file - remove sysfs attribute file.
1313 * @dev: device.
1314 * @attr: device attribute descriptor.
1315 */
1316void device_remove_file(struct device *dev,
1317			const struct device_attribute *attr)
1318{
1319	if (dev)
1320		sysfs_remove_file(&dev->kobj, &attr->attr);
1321}
1322EXPORT_SYMBOL_GPL(device_remove_file);
1323
1324/**
1325 * device_remove_file_self - remove sysfs attribute file from its own method.
1326 * @dev: device.
1327 * @attr: device attribute descriptor.
1328 *
1329 * See kernfs_remove_self() for details.
1330 */
1331bool device_remove_file_self(struct device *dev,
1332			     const struct device_attribute *attr)
1333{
1334	if (dev)
1335		return sysfs_remove_file_self(&dev->kobj, &attr->attr);
1336	else
1337		return false;
1338}
1339EXPORT_SYMBOL_GPL(device_remove_file_self);
1340
1341/**
1342 * device_create_bin_file - create sysfs binary attribute file for device.
1343 * @dev: device.
1344 * @attr: device binary attribute descriptor.
1345 */
1346int device_create_bin_file(struct device *dev,
1347			   const struct bin_attribute *attr)
1348{
1349	int error = -EINVAL;
1350	if (dev)
1351		error = sysfs_create_bin_file(&dev->kobj, attr);
1352	return error;
1353}
1354EXPORT_SYMBOL_GPL(device_create_bin_file);
1355
1356/**
1357 * device_remove_bin_file - remove sysfs binary attribute file
1358 * @dev: device.
1359 * @attr: device binary attribute descriptor.
1360 */
1361void device_remove_bin_file(struct device *dev,
1362			    const struct bin_attribute *attr)
1363{
1364	if (dev)
1365		sysfs_remove_bin_file(&dev->kobj, attr);
1366}
1367EXPORT_SYMBOL_GPL(device_remove_bin_file);
1368
1369static void klist_children_get(struct klist_node *n)
1370{
1371	struct device_private *p = to_device_private_parent(n);
1372	struct device *dev = p->device;
1373
1374	get_device(dev);
1375}
1376
1377static void klist_children_put(struct klist_node *n)
1378{
1379	struct device_private *p = to_device_private_parent(n);
1380	struct device *dev = p->device;
1381
1382	put_device(dev);
1383}
1384
1385/**
1386 * device_initialize - init device structure.
1387 * @dev: device.
1388 *
1389 * This prepares the device for use by other layers by initializing
1390 * its fields.
1391 * It is the first half of device_register(), if called by
1392 * that function, though it can also be called separately, so one
1393 * may use @dev's fields. In particular, get_device()/put_device()
1394 * may be used for reference counting of @dev after calling this
1395 * function.
1396 *
1397 * All fields in @dev must be initialized by the caller to 0, except
1398 * for those explicitly set to some other value.  The simplest
1399 * approach is to use kzalloc() to allocate the structure containing
1400 * @dev.
1401 *
1402 * NOTE: Use put_device() to give up your reference instead of freeing
1403 * @dev directly once you have called this function.
1404 */
1405void device_initialize(struct device *dev)
1406{
1407	dev->kobj.kset = devices_kset;
1408	kobject_init(&dev->kobj, &device_ktype);
1409	INIT_LIST_HEAD(&dev->dma_pools);
1410	mutex_init(&dev->mutex);
1411	lockdep_set_novalidate_class(&dev->mutex);
1412	spin_lock_init(&dev->devres_lock);
1413	INIT_LIST_HEAD(&dev->devres_head);
1414	device_pm_init(dev);
1415	set_dev_node(dev, -1);
1416#ifdef CONFIG_GENERIC_MSI_IRQ
1417	INIT_LIST_HEAD(&dev->msi_list);
1418#endif
1419	INIT_LIST_HEAD(&dev->links.consumers);
1420	INIT_LIST_HEAD(&dev->links.suppliers);
1421	dev->links.status = DL_DEV_NO_DRIVER;
1422}
1423EXPORT_SYMBOL_GPL(device_initialize);
1424
1425struct kobject *virtual_device_parent(struct device *dev)
1426{
1427	static struct kobject *virtual_dir = NULL;
1428
1429	if (!virtual_dir)
1430		virtual_dir = kobject_create_and_add("virtual",
1431						     &devices_kset->kobj);
1432
1433	return virtual_dir;
1434}
1435
1436struct class_dir {
1437	struct kobject kobj;
1438	struct class *class;
1439};
1440
1441#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
1442
1443static void class_dir_release(struct kobject *kobj)
1444{
1445	struct class_dir *dir = to_class_dir(kobj);
1446	kfree(dir);
1447}
1448
1449static const
1450struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
1451{
1452	struct class_dir *dir = to_class_dir(kobj);
1453	return dir->class->ns_type;
1454}
1455
1456static struct kobj_type class_dir_ktype = {
1457	.release	= class_dir_release,
1458	.sysfs_ops	= &kobj_sysfs_ops,
1459	.child_ns_type	= class_dir_child_ns_type
1460};
1461
1462static struct kobject *
1463class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
1464{
1465	struct class_dir *dir;
1466	int retval;
1467
1468	dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1469	if (!dir)
1470		return NULL;
1471
1472	dir->class = class;
1473	kobject_init(&dir->kobj, &class_dir_ktype);
1474
1475	dir->kobj.kset = &class->p->glue_dirs;
1476
1477	retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
1478	if (retval < 0) {
1479		kobject_put(&dir->kobj);
1480		return NULL;
1481	}
1482	return &dir->kobj;
1483}
1484
1485static DEFINE_MUTEX(gdp_mutex);
1486
1487static struct kobject *get_device_parent(struct device *dev,
1488					 struct device *parent)
1489{
1490	if (dev->class) {
 
1491		struct kobject *kobj = NULL;
1492		struct kobject *parent_kobj;
1493		struct kobject *k;
1494
1495#ifdef CONFIG_BLOCK
1496		/* block disks show up in /sys/block */
1497		if (sysfs_deprecated && dev->class == &block_class) {
1498			if (parent && parent->class == &block_class)
1499				return &parent->kobj;
1500			return &block_class.p->subsys.kobj;
1501		}
1502#endif
1503
1504		/*
1505		 * If we have no parent, we live in "virtual".
1506		 * Class-devices with a non class-device as parent, live
1507		 * in a "glue" directory to prevent namespace collisions.
1508		 */
1509		if (parent == NULL)
1510			parent_kobj = virtual_device_parent(dev);
1511		else if (parent->class && !dev->class->ns_type)
1512			return &parent->kobj;
1513		else
1514			parent_kobj = &parent->kobj;
1515
1516		mutex_lock(&gdp_mutex);
1517
1518		/* find our class-directory at the parent and reference it */
1519		spin_lock(&dev->class->p->glue_dirs.list_lock);
1520		list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
1521			if (k->parent == parent_kobj) {
1522				kobj = kobject_get(k);
1523				break;
1524			}
1525		spin_unlock(&dev->class->p->glue_dirs.list_lock);
1526		if (kobj) {
1527			mutex_unlock(&gdp_mutex);
1528			return kobj;
1529		}
1530
1531		/* or create a new class-directory at the parent device */
1532		k = class_dir_create_and_add(dev->class, parent_kobj);
1533		/* do not emit an uevent for this simple "glue" directory */
1534		mutex_unlock(&gdp_mutex);
1535		return k;
1536	}
1537
1538	/* subsystems can specify a default root directory for their devices */
1539	if (!parent && dev->bus && dev->bus->dev_root)
1540		return &dev->bus->dev_root->kobj;
1541
1542	if (parent)
1543		return &parent->kobj;
1544	return NULL;
1545}
1546
1547static inline bool live_in_glue_dir(struct kobject *kobj,
1548				    struct device *dev)
1549{
1550	if (!kobj || !dev->class ||
1551	    kobj->kset != &dev->class->p->glue_dirs)
1552		return false;
1553	return true;
1554}
1555
1556static inline struct kobject *get_glue_dir(struct device *dev)
1557{
1558	return dev->kobj.parent;
1559}
1560
1561/*
1562 * make sure cleaning up dir as the last step, we need to make
1563 * sure .release handler of kobject is run with holding the
1564 * global lock
1565 */
1566static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
1567{
1568	/* see if we live in a "glue" directory */
1569	if (!live_in_glue_dir(glue_dir, dev))
 
1570		return;
1571
1572	mutex_lock(&gdp_mutex);
1573	kobject_put(glue_dir);
1574	mutex_unlock(&gdp_mutex);
 
 
 
 
1575}
1576
1577static int device_add_class_symlinks(struct device *dev)
1578{
1579	struct device_node *of_node = dev_of_node(dev);
1580	int error;
1581
1582	if (of_node) {
1583		error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
1584		if (error)
1585			dev_warn(dev, "Error %d creating of_node link\n",error);
1586		/* An error here doesn't warrant bringing down the device */
1587	}
1588
1589	if (!dev->class)
1590		return 0;
1591
1592	error = sysfs_create_link(&dev->kobj,
1593				  &dev->class->p->subsys.kobj,
1594				  "subsystem");
1595	if (error)
1596		goto out_devnode;
1597
1598	if (dev->parent && device_is_not_partition(dev)) {
1599		error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
1600					  "device");
1601		if (error)
1602			goto out_subsys;
1603	}
1604
1605#ifdef CONFIG_BLOCK
1606	/* /sys/block has directories and does not need symlinks */
1607	if (sysfs_deprecated && dev->class == &block_class)
1608		return 0;
1609#endif
1610
1611	/* link in the class directory pointing to the device */
1612	error = sysfs_create_link(&dev->class->p->subsys.kobj,
1613				  &dev->kobj, dev_name(dev));
1614	if (error)
1615		goto out_device;
1616
1617	return 0;
1618
1619out_device:
1620	sysfs_remove_link(&dev->kobj, "device");
1621
1622out_subsys:
1623	sysfs_remove_link(&dev->kobj, "subsystem");
1624out_devnode:
1625	sysfs_remove_link(&dev->kobj, "of_node");
1626	return error;
1627}
1628
1629static void device_remove_class_symlinks(struct device *dev)
1630{
1631	if (dev_of_node(dev))
1632		sysfs_remove_link(&dev->kobj, "of_node");
1633
1634	if (!dev->class)
1635		return;
1636
1637	if (dev->parent && device_is_not_partition(dev))
1638		sysfs_remove_link(&dev->kobj, "device");
1639	sysfs_remove_link(&dev->kobj, "subsystem");
1640#ifdef CONFIG_BLOCK
1641	if (sysfs_deprecated && dev->class == &block_class)
1642		return;
1643#endif
1644	sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
1645}
1646
1647/**
1648 * dev_set_name - set a device name
1649 * @dev: device
1650 * @fmt: format string for the device's name
1651 */
1652int dev_set_name(struct device *dev, const char *fmt, ...)
1653{
1654	va_list vargs;
1655	int err;
1656
1657	va_start(vargs, fmt);
1658	err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
1659	va_end(vargs);
1660	return err;
1661}
1662EXPORT_SYMBOL_GPL(dev_set_name);
1663
1664/**
1665 * device_to_dev_kobj - select a /sys/dev/ directory for the device
1666 * @dev: device
1667 *
1668 * By default we select char/ for new entries.  Setting class->dev_obj
1669 * to NULL prevents an entry from being created.  class->dev_kobj must
1670 * be set (or cleared) before any devices are registered to the class
1671 * otherwise device_create_sys_dev_entry() and
1672 * device_remove_sys_dev_entry() will disagree about the presence of
1673 * the link.
1674 */
1675static struct kobject *device_to_dev_kobj(struct device *dev)
1676{
1677	struct kobject *kobj;
1678
1679	if (dev->class)
1680		kobj = dev->class->dev_kobj;
1681	else
1682		kobj = sysfs_dev_char_kobj;
1683
1684	return kobj;
1685}
1686
1687static int device_create_sys_dev_entry(struct device *dev)
1688{
1689	struct kobject *kobj = device_to_dev_kobj(dev);
1690	int error = 0;
1691	char devt_str[15];
1692
1693	if (kobj) {
1694		format_dev_t(devt_str, dev->devt);
1695		error = sysfs_create_link(kobj, &dev->kobj, devt_str);
1696	}
1697
1698	return error;
1699}
1700
1701static void device_remove_sys_dev_entry(struct device *dev)
1702{
1703	struct kobject *kobj = device_to_dev_kobj(dev);
1704	char devt_str[15];
1705
1706	if (kobj) {
1707		format_dev_t(devt_str, dev->devt);
1708		sysfs_remove_link(kobj, devt_str);
1709	}
1710}
1711
1712int device_private_init(struct device *dev)
1713{
1714	dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
1715	if (!dev->p)
1716		return -ENOMEM;
1717	dev->p->device = dev;
1718	klist_init(&dev->p->klist_children, klist_children_get,
1719		   klist_children_put);
1720	INIT_LIST_HEAD(&dev->p->deferred_probe);
1721	return 0;
1722}
1723
1724/**
1725 * device_add - add device to device hierarchy.
1726 * @dev: device.
1727 *
1728 * This is part 2 of device_register(), though may be called
1729 * separately _iff_ device_initialize() has been called separately.
1730 *
1731 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
1732 * to the global and sibling lists for the device, then
1733 * adds it to the other relevant subsystems of the driver model.
1734 *
1735 * Do not call this routine or device_register() more than once for
1736 * any device structure.  The driver model core is not designed to work
1737 * with devices that get unregistered and then spring back to life.
1738 * (Among other things, it's very hard to guarantee that all references
1739 * to the previous incarnation of @dev have been dropped.)  Allocate
1740 * and register a fresh new struct device instead.
1741 *
1742 * NOTE: _Never_ directly free @dev after calling this function, even
1743 * if it returned an error! Always use put_device() to give up your
1744 * reference instead.
1745 */
1746int device_add(struct device *dev)
1747{
1748	struct device *parent;
1749	struct kobject *kobj;
1750	struct class_interface *class_intf;
1751	int error = -EINVAL;
1752	struct kobject *glue_dir = NULL;
1753
1754	dev = get_device(dev);
1755	if (!dev)
1756		goto done;
1757
1758	if (!dev->p) {
1759		error = device_private_init(dev);
1760		if (error)
1761			goto done;
1762	}
1763
1764	/*
1765	 * for statically allocated devices, which should all be converted
1766	 * some day, we need to initialize the name. We prevent reading back
1767	 * the name, and force the use of dev_name()
1768	 */
1769	if (dev->init_name) {
1770		dev_set_name(dev, "%s", dev->init_name);
1771		dev->init_name = NULL;
1772	}
1773
1774	/* subsystems can specify simple device enumeration */
1775	if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
1776		dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
1777
1778	if (!dev_name(dev)) {
1779		error = -EINVAL;
1780		goto name_error;
1781	}
1782
1783	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1784
1785	parent = get_device(dev->parent);
1786	kobj = get_device_parent(dev, parent);
1787	if (kobj)
1788		dev->kobj.parent = kobj;
1789
1790	/* use parent numa_node */
1791	if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
1792		set_dev_node(dev, dev_to_node(parent));
1793
1794	/* first, register with generic layer. */
1795	/* we require the name to be set before, and pass NULL */
1796	error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
1797	if (error) {
1798		glue_dir = get_glue_dir(dev);
1799		goto Error;
1800	}
1801
1802	/* notify platform of device entry */
1803	if (platform_notify)
1804		platform_notify(dev);
1805
1806	error = device_create_file(dev, &dev_attr_uevent);
1807	if (error)
1808		goto attrError;
1809
 
 
 
 
 
 
 
 
 
 
 
 
1810	error = device_add_class_symlinks(dev);
1811	if (error)
1812		goto SymlinkError;
1813	error = device_add_attrs(dev);
1814	if (error)
1815		goto AttrsError;
1816	error = bus_add_device(dev);
1817	if (error)
1818		goto BusError;
1819	error = dpm_sysfs_add(dev);
1820	if (error)
1821		goto DPMError;
1822	device_pm_add(dev);
1823
1824	if (MAJOR(dev->devt)) {
1825		error = device_create_file(dev, &dev_attr_dev);
1826		if (error)
1827			goto DevAttrError;
1828
1829		error = device_create_sys_dev_entry(dev);
1830		if (error)
1831			goto SysEntryError;
1832
1833		devtmpfs_create_node(dev);
1834	}
1835
1836	/* Notify clients of device addition.  This call must come
1837	 * after dpm_sysfs_add() and before kobject_uevent().
1838	 */
1839	if (dev->bus)
1840		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1841					     BUS_NOTIFY_ADD_DEVICE, dev);
1842
1843	kobject_uevent(&dev->kobj, KOBJ_ADD);
1844	bus_probe_device(dev);
1845	if (parent)
1846		klist_add_tail(&dev->p->knode_parent,
1847			       &parent->p->klist_children);
1848
1849	if (dev->class) {
1850		mutex_lock(&dev->class->p->mutex);
1851		/* tie the class to the device */
1852		klist_add_tail(&dev->knode_class,
1853			       &dev->class->p->klist_devices);
1854
1855		/* notify any interfaces that the device is here */
1856		list_for_each_entry(class_intf,
1857				    &dev->class->p->interfaces, node)
1858			if (class_intf->add_dev)
1859				class_intf->add_dev(dev, class_intf);
1860		mutex_unlock(&dev->class->p->mutex);
1861	}
1862done:
1863	put_device(dev);
1864	return error;
1865 SysEntryError:
1866	if (MAJOR(dev->devt))
1867		device_remove_file(dev, &dev_attr_dev);
1868 DevAttrError:
1869	device_pm_remove(dev);
1870	dpm_sysfs_remove(dev);
1871 DPMError:
1872	bus_remove_device(dev);
1873 BusError:
1874	device_remove_attrs(dev);
1875 AttrsError:
1876	device_remove_class_symlinks(dev);
1877 SymlinkError:
 
 
 
 
 
 
 
 
1878	device_remove_file(dev, &dev_attr_uevent);
1879 attrError:
1880	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1881	glue_dir = get_glue_dir(dev);
1882	kobject_del(&dev->kobj);
1883 Error:
1884	cleanup_glue_dir(dev, glue_dir);
1885	put_device(parent);
 
1886name_error:
1887	kfree(dev->p);
1888	dev->p = NULL;
1889	goto done;
1890}
1891EXPORT_SYMBOL_GPL(device_add);
1892
1893/**
1894 * device_register - register a device with the system.
1895 * @dev: pointer to the device structure
1896 *
1897 * This happens in two clean steps - initialize the device
1898 * and add it to the system. The two steps can be called
1899 * separately, but this is the easiest and most common.
1900 * I.e. you should only call the two helpers separately if
1901 * have a clearly defined need to use and refcount the device
1902 * before it is added to the hierarchy.
1903 *
1904 * For more information, see the kerneldoc for device_initialize()
1905 * and device_add().
1906 *
1907 * NOTE: _Never_ directly free @dev after calling this function, even
1908 * if it returned an error! Always use put_device() to give up the
1909 * reference initialized in this function instead.
1910 */
1911int device_register(struct device *dev)
1912{
1913	device_initialize(dev);
1914	return device_add(dev);
1915}
1916EXPORT_SYMBOL_GPL(device_register);
1917
1918/**
1919 * get_device - increment reference count for device.
1920 * @dev: device.
1921 *
1922 * This simply forwards the call to kobject_get(), though
1923 * we do take care to provide for the case that we get a NULL
1924 * pointer passed in.
1925 */
1926struct device *get_device(struct device *dev)
1927{
1928	return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
1929}
1930EXPORT_SYMBOL_GPL(get_device);
1931
1932/**
1933 * put_device - decrement reference count.
1934 * @dev: device in question.
1935 */
1936void put_device(struct device *dev)
1937{
1938	/* might_sleep(); */
1939	if (dev)
1940		kobject_put(&dev->kobj);
1941}
1942EXPORT_SYMBOL_GPL(put_device);
1943
1944/**
1945 * device_del - delete device from system.
1946 * @dev: device.
1947 *
1948 * This is the first part of the device unregistration
1949 * sequence. This removes the device from the lists we control
1950 * from here, has it removed from the other driver model
1951 * subsystems it was added to in device_add(), and removes it
1952 * from the kobject hierarchy.
1953 *
1954 * NOTE: this should be called manually _iff_ device_add() was
1955 * also called manually.
1956 */
1957void device_del(struct device *dev)
1958{
1959	struct device *parent = dev->parent;
1960	struct kobject *glue_dir = NULL;
1961	struct class_interface *class_intf;
1962
1963	/* Notify clients of device removal.  This call must come
1964	 * before dpm_sysfs_remove().
1965	 */
1966	if (dev->bus)
1967		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1968					     BUS_NOTIFY_DEL_DEVICE, dev);
1969
1970	dpm_sysfs_remove(dev);
1971	if (parent)
1972		klist_del(&dev->p->knode_parent);
1973	if (MAJOR(dev->devt)) {
1974		devtmpfs_delete_node(dev);
1975		device_remove_sys_dev_entry(dev);
1976		device_remove_file(dev, &dev_attr_dev);
1977	}
1978	if (dev->class) {
1979		device_remove_class_symlinks(dev);
1980
1981		mutex_lock(&dev->class->p->mutex);
1982		/* notify any interfaces that the device is now gone */
1983		list_for_each_entry(class_intf,
1984				    &dev->class->p->interfaces, node)
1985			if (class_intf->remove_dev)
1986				class_intf->remove_dev(dev, class_intf);
1987		/* remove the device from the class list */
1988		klist_del(&dev->knode_class);
1989		mutex_unlock(&dev->class->p->mutex);
1990	}
1991	device_remove_file(dev, &dev_attr_uevent);
1992	device_remove_attrs(dev);
1993	bus_remove_device(dev);
1994	device_pm_remove(dev);
1995	driver_deferred_probe_del(dev);
1996	device_remove_properties(dev);
1997	device_links_purge(dev);
1998
1999	/* Notify the platform of the removal, in case they
2000	 * need to do anything...
2001	 */
2002	if (platform_notify_remove)
2003		platform_notify_remove(dev);
2004	if (dev->bus)
2005		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
2006					     BUS_NOTIFY_REMOVED_DEVICE, dev);
2007	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
2008	glue_dir = get_glue_dir(dev);
2009	kobject_del(&dev->kobj);
2010	cleanup_glue_dir(dev, glue_dir);
2011	put_device(parent);
2012}
2013EXPORT_SYMBOL_GPL(device_del);
2014
2015/**
2016 * device_unregister - unregister device from system.
2017 * @dev: device going away.
2018 *
2019 * We do this in two parts, like we do device_register(). First,
2020 * we remove it from all the subsystems with device_del(), then
2021 * we decrement the reference count via put_device(). If that
2022 * is the final reference count, the device will be cleaned up
2023 * via device_release() above. Otherwise, the structure will
2024 * stick around until the final reference to the device is dropped.
2025 */
2026void device_unregister(struct device *dev)
2027{
2028	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
2029	device_del(dev);
2030	put_device(dev);
2031}
2032EXPORT_SYMBOL_GPL(device_unregister);
2033
2034static struct device *prev_device(struct klist_iter *i)
2035{
2036	struct klist_node *n = klist_prev(i);
2037	struct device *dev = NULL;
2038	struct device_private *p;
2039
2040	if (n) {
2041		p = to_device_private_parent(n);
2042		dev = p->device;
2043	}
2044	return dev;
2045}
2046
2047static struct device *next_device(struct klist_iter *i)
2048{
2049	struct klist_node *n = klist_next(i);
2050	struct device *dev = NULL;
2051	struct device_private *p;
2052
2053	if (n) {
2054		p = to_device_private_parent(n);
2055		dev = p->device;
2056	}
2057	return dev;
2058}
2059
2060/**
2061 * device_get_devnode - path of device node file
2062 * @dev: device
2063 * @mode: returned file access mode
2064 * @uid: returned file owner
2065 * @gid: returned file group
2066 * @tmp: possibly allocated string
2067 *
2068 * Return the relative path of a possible device node.
2069 * Non-default names may need to allocate a memory to compose
2070 * a name. This memory is returned in tmp and needs to be
2071 * freed by the caller.
2072 */
2073const char *device_get_devnode(struct device *dev,
2074			       umode_t *mode, kuid_t *uid, kgid_t *gid,
2075			       const char **tmp)
2076{
2077	char *s;
2078
2079	*tmp = NULL;
2080
2081	/* the device type may provide a specific name */
2082	if (dev->type && dev->type->devnode)
2083		*tmp = dev->type->devnode(dev, mode, uid, gid);
2084	if (*tmp)
2085		return *tmp;
2086
2087	/* the class may provide a specific name */
2088	if (dev->class && dev->class->devnode)
2089		*tmp = dev->class->devnode(dev, mode);
2090	if (*tmp)
2091		return *tmp;
2092
2093	/* return name without allocation, tmp == NULL */
2094	if (strchr(dev_name(dev), '!') == NULL)
2095		return dev_name(dev);
2096
2097	/* replace '!' in the name with '/' */
2098	s = kstrdup(dev_name(dev), GFP_KERNEL);
2099	if (!s)
2100		return NULL;
2101	strreplace(s, '!', '/');
2102	return *tmp = s;
 
2103}
2104
2105/**
2106 * device_for_each_child - device child iterator.
2107 * @parent: parent struct device.
2108 * @fn: function to be called for each device.
2109 * @data: data for the callback.
2110 *
2111 * Iterate over @parent's child devices, and call @fn for each,
2112 * passing it @data.
2113 *
2114 * We check the return of @fn each time. If it returns anything
2115 * other than 0, we break out and return that value.
2116 */
2117int device_for_each_child(struct device *parent, void *data,
2118			  int (*fn)(struct device *dev, void *data))
2119{
2120	struct klist_iter i;
2121	struct device *child;
2122	int error = 0;
2123
2124	if (!parent->p)
2125		return 0;
2126
2127	klist_iter_init(&parent->p->klist_children, &i);
2128	while (!error && (child = next_device(&i)))
2129		error = fn(child, data);
2130	klist_iter_exit(&i);
2131	return error;
2132}
2133EXPORT_SYMBOL_GPL(device_for_each_child);
2134
2135/**
2136 * device_for_each_child_reverse - device child iterator in reversed order.
2137 * @parent: parent struct device.
2138 * @fn: function to be called for each device.
2139 * @data: data for the callback.
2140 *
2141 * Iterate over @parent's child devices, and call @fn for each,
2142 * passing it @data.
2143 *
2144 * We check the return of @fn each time. If it returns anything
2145 * other than 0, we break out and return that value.
2146 */
2147int device_for_each_child_reverse(struct device *parent, void *data,
2148				  int (*fn)(struct device *dev, void *data))
2149{
2150	struct klist_iter i;
2151	struct device *child;
2152	int error = 0;
2153
2154	if (!parent->p)
2155		return 0;
2156
2157	klist_iter_init(&parent->p->klist_children, &i);
2158	while ((child = prev_device(&i)) && !error)
2159		error = fn(child, data);
2160	klist_iter_exit(&i);
2161	return error;
2162}
2163EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
2164
2165/**
2166 * device_find_child - device iterator for locating a particular device.
2167 * @parent: parent struct device
2168 * @match: Callback function to check device
2169 * @data: Data to pass to match function
2170 *
2171 * This is similar to the device_for_each_child() function above, but it
2172 * returns a reference to a device that is 'found' for later use, as
2173 * determined by the @match callback.
2174 *
2175 * The callback should return 0 if the device doesn't match and non-zero
2176 * if it does.  If the callback returns non-zero and a reference to the
2177 * current device can be obtained, this function will return to the caller
2178 * and not iterate over any more devices.
2179 *
2180 * NOTE: you will need to drop the reference with put_device() after use.
2181 */
2182struct device *device_find_child(struct device *parent, void *data,
2183				 int (*match)(struct device *dev, void *data))
2184{
2185	struct klist_iter i;
2186	struct device *child;
2187
2188	if (!parent)
2189		return NULL;
2190
2191	klist_iter_init(&parent->p->klist_children, &i);
2192	while ((child = next_device(&i)))
2193		if (match(child, data) && get_device(child))
2194			break;
2195	klist_iter_exit(&i);
2196	return child;
2197}
2198EXPORT_SYMBOL_GPL(device_find_child);
2199
2200int __init devices_init(void)
2201{
2202	devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
2203	if (!devices_kset)
2204		return -ENOMEM;
2205	dev_kobj = kobject_create_and_add("dev", NULL);
2206	if (!dev_kobj)
2207		goto dev_kobj_err;
2208	sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
2209	if (!sysfs_dev_block_kobj)
2210		goto block_kobj_err;
2211	sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
2212	if (!sysfs_dev_char_kobj)
2213		goto char_kobj_err;
2214
2215	return 0;
2216
2217 char_kobj_err:
2218	kobject_put(sysfs_dev_block_kobj);
2219 block_kobj_err:
2220	kobject_put(dev_kobj);
2221 dev_kobj_err:
2222	kset_unregister(devices_kset);
2223	return -ENOMEM;
2224}
2225
2226static int device_check_offline(struct device *dev, void *not_used)
2227{
2228	int ret;
2229
2230	ret = device_for_each_child(dev, NULL, device_check_offline);
2231	if (ret)
2232		return ret;
2233
2234	return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
2235}
2236
2237/**
2238 * device_offline - Prepare the device for hot-removal.
2239 * @dev: Device to be put offline.
2240 *
2241 * Execute the device bus type's .offline() callback, if present, to prepare
2242 * the device for a subsequent hot-removal.  If that succeeds, the device must
2243 * not be used until either it is removed or its bus type's .online() callback
2244 * is executed.
2245 *
2246 * Call under device_hotplug_lock.
2247 */
2248int device_offline(struct device *dev)
2249{
2250	int ret;
2251
2252	if (dev->offline_disabled)
2253		return -EPERM;
2254
2255	ret = device_for_each_child(dev, NULL, device_check_offline);
2256	if (ret)
2257		return ret;
2258
2259	device_lock(dev);
2260	if (device_supports_offline(dev)) {
2261		if (dev->offline) {
2262			ret = 1;
2263		} else {
2264			ret = dev->bus->offline(dev);
2265			if (!ret) {
2266				kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
2267				dev->offline = true;
2268			}
2269		}
2270	}
2271	device_unlock(dev);
2272
2273	return ret;
2274}
2275
2276/**
2277 * device_online - Put the device back online after successful device_offline().
2278 * @dev: Device to be put back online.
2279 *
2280 * If device_offline() has been successfully executed for @dev, but the device
2281 * has not been removed subsequently, execute its bus type's .online() callback
2282 * to indicate that the device can be used again.
2283 *
2284 * Call under device_hotplug_lock.
2285 */
2286int device_online(struct device *dev)
2287{
2288	int ret = 0;
2289
2290	device_lock(dev);
2291	if (device_supports_offline(dev)) {
2292		if (dev->offline) {
2293			ret = dev->bus->online(dev);
2294			if (!ret) {
2295				kobject_uevent(&dev->kobj, KOBJ_ONLINE);
2296				dev->offline = false;
2297			}
2298		} else {
2299			ret = 1;
2300		}
2301	}
2302	device_unlock(dev);
2303
2304	return ret;
2305}
2306
2307struct root_device {
2308	struct device dev;
2309	struct module *owner;
2310};
2311
2312static inline struct root_device *to_root_device(struct device *d)
2313{
2314	return container_of(d, struct root_device, dev);
2315}
2316
2317static void root_device_release(struct device *dev)
2318{
2319	kfree(to_root_device(dev));
2320}
2321
2322/**
2323 * __root_device_register - allocate and register a root device
2324 * @name: root device name
2325 * @owner: owner module of the root device, usually THIS_MODULE
2326 *
2327 * This function allocates a root device and registers it
2328 * using device_register(). In order to free the returned
2329 * device, use root_device_unregister().
2330 *
2331 * Root devices are dummy devices which allow other devices
2332 * to be grouped under /sys/devices. Use this function to
2333 * allocate a root device and then use it as the parent of
2334 * any device which should appear under /sys/devices/{name}
2335 *
2336 * The /sys/devices/{name} directory will also contain a
2337 * 'module' symlink which points to the @owner directory
2338 * in sysfs.
2339 *
2340 * Returns &struct device pointer on success, or ERR_PTR() on error.
2341 *
2342 * Note: You probably want to use root_device_register().
2343 */
2344struct device *__root_device_register(const char *name, struct module *owner)
2345{
2346	struct root_device *root;
2347	int err = -ENOMEM;
2348
2349	root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
2350	if (!root)
2351		return ERR_PTR(err);
2352
2353	err = dev_set_name(&root->dev, "%s", name);
2354	if (err) {
2355		kfree(root);
2356		return ERR_PTR(err);
2357	}
2358
2359	root->dev.release = root_device_release;
2360
2361	err = device_register(&root->dev);
2362	if (err) {
2363		put_device(&root->dev);
2364		return ERR_PTR(err);
2365	}
2366
2367#ifdef CONFIG_MODULES	/* gotta find a "cleaner" way to do this */
2368	if (owner) {
2369		struct module_kobject *mk = &owner->mkobj;
2370
2371		err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
2372		if (err) {
2373			device_unregister(&root->dev);
2374			return ERR_PTR(err);
2375		}
2376		root->owner = owner;
2377	}
2378#endif
2379
2380	return &root->dev;
2381}
2382EXPORT_SYMBOL_GPL(__root_device_register);
2383
2384/**
2385 * root_device_unregister - unregister and free a root device
2386 * @dev: device going away
2387 *
2388 * This function unregisters and cleans up a device that was created by
2389 * root_device_register().
2390 */
2391void root_device_unregister(struct device *dev)
2392{
2393	struct root_device *root = to_root_device(dev);
2394
2395	if (root->owner)
2396		sysfs_remove_link(&root->dev.kobj, "module");
2397
2398	device_unregister(dev);
2399}
2400EXPORT_SYMBOL_GPL(root_device_unregister);
2401
2402
2403static void device_create_release(struct device *dev)
2404{
2405	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
2406	kfree(dev);
2407}
2408
2409static struct device *
2410device_create_groups_vargs(struct class *class, struct device *parent,
2411			   dev_t devt, void *drvdata,
2412			   const struct attribute_group **groups,
2413			   const char *fmt, va_list args)
2414{
2415	struct device *dev = NULL;
2416	int retval = -ENODEV;
2417
2418	if (class == NULL || IS_ERR(class))
2419		goto error;
2420
2421	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
2422	if (!dev) {
2423		retval = -ENOMEM;
2424		goto error;
2425	}
2426
2427	device_initialize(dev);
2428	dev->devt = devt;
2429	dev->class = class;
2430	dev->parent = parent;
2431	dev->groups = groups;
2432	dev->release = device_create_release;
2433	dev_set_drvdata(dev, drvdata);
2434
2435	retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
2436	if (retval)
2437		goto error;
2438
2439	retval = device_add(dev);
2440	if (retval)
2441		goto error;
2442
2443	return dev;
2444
2445error:
2446	put_device(dev);
2447	return ERR_PTR(retval);
2448}
2449
2450/**
2451 * device_create_vargs - creates a device and registers it with sysfs
2452 * @class: pointer to the struct class that this device should be registered to
2453 * @parent: pointer to the parent struct device of this new device, if any
2454 * @devt: the dev_t for the char device to be added
2455 * @drvdata: the data to be added to the device for callbacks
2456 * @fmt: string for the device's name
2457 * @args: va_list for the device's name
2458 *
2459 * This function can be used by char device classes.  A struct device
2460 * will be created in sysfs, registered to the specified class.
2461 *
2462 * A "dev" file will be created, showing the dev_t for the device, if
2463 * the dev_t is not 0,0.
2464 * If a pointer to a parent struct device is passed in, the newly created
2465 * struct device will be a child of that device in sysfs.
2466 * The pointer to the struct device will be returned from the call.
2467 * Any further sysfs files that might be required can be created using this
2468 * pointer.
2469 *
2470 * Returns &struct device pointer on success, or ERR_PTR() on error.
2471 *
2472 * Note: the struct class passed to this function must have previously
2473 * been created with a call to class_create().
2474 */
2475struct device *device_create_vargs(struct class *class, struct device *parent,
2476				   dev_t devt, void *drvdata, const char *fmt,
2477				   va_list args)
2478{
2479	return device_create_groups_vargs(class, parent, devt, drvdata, NULL,
2480					  fmt, args);
2481}
2482EXPORT_SYMBOL_GPL(device_create_vargs);
2483
2484/**
2485 * device_create - creates a device and registers it with sysfs
2486 * @class: pointer to the struct class that this device should be registered to
2487 * @parent: pointer to the parent struct device of this new device, if any
2488 * @devt: the dev_t for the char device to be added
2489 * @drvdata: the data to be added to the device for callbacks
2490 * @fmt: string for the device's name
2491 *
2492 * This function can be used by char device classes.  A struct device
2493 * will be created in sysfs, registered to the specified class.
2494 *
2495 * A "dev" file will be created, showing the dev_t for the device, if
2496 * the dev_t is not 0,0.
2497 * If a pointer to a parent struct device is passed in, the newly created
2498 * struct device will be a child of that device in sysfs.
2499 * The pointer to the struct device will be returned from the call.
2500 * Any further sysfs files that might be required can be created using this
2501 * pointer.
2502 *
2503 * Returns &struct device pointer on success, or ERR_PTR() on error.
2504 *
2505 * Note: the struct class passed to this function must have previously
2506 * been created with a call to class_create().
2507 */
2508struct device *device_create(struct class *class, struct device *parent,
2509			     dev_t devt, void *drvdata, const char *fmt, ...)
2510{
2511	va_list vargs;
2512	struct device *dev;
2513
2514	va_start(vargs, fmt);
2515	dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
2516	va_end(vargs);
2517	return dev;
2518}
2519EXPORT_SYMBOL_GPL(device_create);
2520
2521/**
2522 * device_create_with_groups - creates a device and registers it with sysfs
2523 * @class: pointer to the struct class that this device should be registered to
2524 * @parent: pointer to the parent struct device of this new device, if any
2525 * @devt: the dev_t for the char device to be added
2526 * @drvdata: the data to be added to the device for callbacks
2527 * @groups: NULL-terminated list of attribute groups to be created
2528 * @fmt: string for the device's name
2529 *
2530 * This function can be used by char device classes.  A struct device
2531 * will be created in sysfs, registered to the specified class.
2532 * Additional attributes specified in the groups parameter will also
2533 * be created automatically.
2534 *
2535 * A "dev" file will be created, showing the dev_t for the device, if
2536 * the dev_t is not 0,0.
2537 * If a pointer to a parent struct device is passed in, the newly created
2538 * struct device will be a child of that device in sysfs.
2539 * The pointer to the struct device will be returned from the call.
2540 * Any further sysfs files that might be required can be created using this
2541 * pointer.
2542 *
2543 * Returns &struct device pointer on success, or ERR_PTR() on error.
2544 *
2545 * Note: the struct class passed to this function must have previously
2546 * been created with a call to class_create().
2547 */
2548struct device *device_create_with_groups(struct class *class,
2549					 struct device *parent, dev_t devt,
2550					 void *drvdata,
2551					 const struct attribute_group **groups,
2552					 const char *fmt, ...)
2553{
2554	va_list vargs;
2555	struct device *dev;
2556
2557	va_start(vargs, fmt);
2558	dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
2559					 fmt, vargs);
2560	va_end(vargs);
2561	return dev;
2562}
2563EXPORT_SYMBOL_GPL(device_create_with_groups);
2564
2565static int __match_devt(struct device *dev, const void *data)
2566{
2567	const dev_t *devt = data;
2568
2569	return dev->devt == *devt;
2570}
2571
2572/**
2573 * device_destroy - removes a device that was created with device_create()
2574 * @class: pointer to the struct class that this device was registered with
2575 * @devt: the dev_t of the device that was previously registered
2576 *
2577 * This call unregisters and cleans up a device that was created with a
2578 * call to device_create().
2579 */
2580void device_destroy(struct class *class, dev_t devt)
2581{
2582	struct device *dev;
2583
2584	dev = class_find_device(class, NULL, &devt, __match_devt);
2585	if (dev) {
2586		put_device(dev);
2587		device_unregister(dev);
2588	}
2589}
2590EXPORT_SYMBOL_GPL(device_destroy);
2591
2592/**
2593 * device_rename - renames a device
2594 * @dev: the pointer to the struct device to be renamed
2595 * @new_name: the new name of the device
2596 *
2597 * It is the responsibility of the caller to provide mutual
2598 * exclusion between two different calls of device_rename
2599 * on the same device to ensure that new_name is valid and
2600 * won't conflict with other devices.
2601 *
2602 * Note: Don't call this function.  Currently, the networking layer calls this
2603 * function, but that will change.  The following text from Kay Sievers offers
2604 * some insight:
2605 *
2606 * Renaming devices is racy at many levels, symlinks and other stuff are not
2607 * replaced atomically, and you get a "move" uevent, but it's not easy to
2608 * connect the event to the old and new device. Device nodes are not renamed at
2609 * all, there isn't even support for that in the kernel now.
2610 *
2611 * In the meantime, during renaming, your target name might be taken by another
2612 * driver, creating conflicts. Or the old name is taken directly after you
2613 * renamed it -- then you get events for the same DEVPATH, before you even see
2614 * the "move" event. It's just a mess, and nothing new should ever rely on
2615 * kernel device renaming. Besides that, it's not even implemented now for
2616 * other things than (driver-core wise very simple) network devices.
2617 *
2618 * We are currently about to change network renaming in udev to completely
2619 * disallow renaming of devices in the same namespace as the kernel uses,
2620 * because we can't solve the problems properly, that arise with swapping names
2621 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
2622 * be allowed to some other name than eth[0-9]*, for the aforementioned
2623 * reasons.
2624 *
2625 * Make up a "real" name in the driver before you register anything, or add
2626 * some other attributes for userspace to find the device, or use udev to add
2627 * symlinks -- but never rename kernel devices later, it's a complete mess. We
2628 * don't even want to get into that and try to implement the missing pieces in
2629 * the core. We really have other pieces to fix in the driver core mess. :)
2630 */
2631int device_rename(struct device *dev, const char *new_name)
2632{
2633	struct kobject *kobj = &dev->kobj;
2634	char *old_device_name = NULL;
2635	int error;
2636
2637	dev = get_device(dev);
2638	if (!dev)
2639		return -EINVAL;
2640
2641	dev_dbg(dev, "renaming to %s\n", new_name);
2642
2643	old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
2644	if (!old_device_name) {
2645		error = -ENOMEM;
2646		goto out;
2647	}
2648
2649	if (dev->class) {
2650		error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
2651					     kobj, old_device_name,
2652					     new_name, kobject_namespace(kobj));
2653		if (error)
2654			goto out;
2655	}
2656
2657	error = kobject_rename(kobj, new_name);
2658	if (error)
2659		goto out;
2660
2661out:
2662	put_device(dev);
2663
2664	kfree(old_device_name);
2665
2666	return error;
2667}
2668EXPORT_SYMBOL_GPL(device_rename);
2669
2670static int device_move_class_links(struct device *dev,
2671				   struct device *old_parent,
2672				   struct device *new_parent)
2673{
2674	int error = 0;
2675
2676	if (old_parent)
2677		sysfs_remove_link(&dev->kobj, "device");
2678	if (new_parent)
2679		error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
2680					  "device");
2681	return error;
2682}
2683
2684/**
2685 * device_move - moves a device to a new parent
2686 * @dev: the pointer to the struct device to be moved
2687 * @new_parent: the new parent of the device (can by NULL)
2688 * @dpm_order: how to reorder the dpm_list
2689 */
2690int device_move(struct device *dev, struct device *new_parent,
2691		enum dpm_order dpm_order)
2692{
2693	int error;
2694	struct device *old_parent;
2695	struct kobject *new_parent_kobj;
2696
2697	dev = get_device(dev);
2698	if (!dev)
2699		return -EINVAL;
2700
2701	device_pm_lock();
2702	new_parent = get_device(new_parent);
2703	new_parent_kobj = get_device_parent(dev, new_parent);
2704
2705	pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
2706		 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
2707	error = kobject_move(&dev->kobj, new_parent_kobj);
2708	if (error) {
2709		cleanup_glue_dir(dev, new_parent_kobj);
2710		put_device(new_parent);
2711		goto out;
2712	}
2713	old_parent = dev->parent;
2714	dev->parent = new_parent;
2715	if (old_parent)
2716		klist_remove(&dev->p->knode_parent);
2717	if (new_parent) {
2718		klist_add_tail(&dev->p->knode_parent,
2719			       &new_parent->p->klist_children);
2720		set_dev_node(dev, dev_to_node(new_parent));
2721	}
2722
2723	if (dev->class) {
2724		error = device_move_class_links(dev, old_parent, new_parent);
2725		if (error) {
2726			/* We ignore errors on cleanup since we're hosed anyway... */
2727			device_move_class_links(dev, new_parent, old_parent);
2728			if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
2729				if (new_parent)
2730					klist_remove(&dev->p->knode_parent);
2731				dev->parent = old_parent;
2732				if (old_parent) {
2733					klist_add_tail(&dev->p->knode_parent,
2734						       &old_parent->p->klist_children);
2735					set_dev_node(dev, dev_to_node(old_parent));
2736				}
2737			}
2738			cleanup_glue_dir(dev, new_parent_kobj);
2739			put_device(new_parent);
2740			goto out;
2741		}
2742	}
2743	switch (dpm_order) {
2744	case DPM_ORDER_NONE:
2745		break;
2746	case DPM_ORDER_DEV_AFTER_PARENT:
2747		device_pm_move_after(dev, new_parent);
2748		devices_kset_move_after(dev, new_parent);
2749		break;
2750	case DPM_ORDER_PARENT_BEFORE_DEV:
2751		device_pm_move_before(new_parent, dev);
2752		devices_kset_move_before(new_parent, dev);
2753		break;
2754	case DPM_ORDER_DEV_LAST:
2755		device_pm_move_last(dev);
2756		devices_kset_move_last(dev);
2757		break;
2758	}
2759
2760	put_device(old_parent);
2761out:
2762	device_pm_unlock();
2763	put_device(dev);
2764	return error;
2765}
2766EXPORT_SYMBOL_GPL(device_move);
2767
2768/**
2769 * device_shutdown - call ->shutdown() on each device to shutdown.
2770 */
2771void device_shutdown(void)
2772{
2773	struct device *dev, *parent;
2774
2775	spin_lock(&devices_kset->list_lock);
2776	/*
2777	 * Walk the devices list backward, shutting down each in turn.
2778	 * Beware that device unplug events may also start pulling
2779	 * devices offline, even as the system is shutting down.
2780	 */
2781	while (!list_empty(&devices_kset->list)) {
2782		dev = list_entry(devices_kset->list.prev, struct device,
2783				kobj.entry);
2784
2785		/*
2786		 * hold reference count of device's parent to
2787		 * prevent it from being freed because parent's
2788		 * lock is to be held
2789		 */
2790		parent = get_device(dev->parent);
2791		get_device(dev);
2792		/*
2793		 * Make sure the device is off the kset list, in the
2794		 * event that dev->*->shutdown() doesn't remove it.
2795		 */
2796		list_del_init(&dev->kobj.entry);
2797		spin_unlock(&devices_kset->list_lock);
2798
2799		/* hold lock to avoid race with probe/release */
2800		if (parent)
2801			device_lock(parent);
2802		device_lock(dev);
2803
2804		/* Don't allow any more runtime suspends */
2805		pm_runtime_get_noresume(dev);
2806		pm_runtime_barrier(dev);
2807
2808		if (dev->class && dev->class->shutdown_pre) {
2809			if (initcall_debug)
2810				dev_info(dev, "shutdown_pre\n");
2811			dev->class->shutdown_pre(dev);
2812		}
2813		if (dev->bus && dev->bus->shutdown) {
2814			if (initcall_debug)
2815				dev_info(dev, "shutdown\n");
2816			dev->bus->shutdown(dev);
2817		} else if (dev->driver && dev->driver->shutdown) {
2818			if (initcall_debug)
2819				dev_info(dev, "shutdown\n");
2820			dev->driver->shutdown(dev);
2821		}
2822
2823		device_unlock(dev);
2824		if (parent)
2825			device_unlock(parent);
2826
2827		put_device(dev);
2828		put_device(parent);
2829
2830		spin_lock(&devices_kset->list_lock);
2831	}
2832	spin_unlock(&devices_kset->list_lock);
2833}
2834
2835/*
2836 * Device logging functions
2837 */
2838
2839#ifdef CONFIG_PRINTK
2840static int
2841create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen)
2842{
2843	const char *subsys;
2844	size_t pos = 0;
2845
2846	if (dev->class)
2847		subsys = dev->class->name;
2848	else if (dev->bus)
2849		subsys = dev->bus->name;
2850	else
2851		return 0;
2852
2853	pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys);
2854	if (pos >= hdrlen)
2855		goto overflow;
2856
2857	/*
2858	 * Add device identifier DEVICE=:
2859	 *   b12:8         block dev_t
2860	 *   c127:3        char dev_t
2861	 *   n8            netdev ifindex
2862	 *   +sound:card0  subsystem:devname
2863	 */
2864	if (MAJOR(dev->devt)) {
2865		char c;
2866
2867		if (strcmp(subsys, "block") == 0)
2868			c = 'b';
2869		else
2870			c = 'c';
2871		pos++;
2872		pos += snprintf(hdr + pos, hdrlen - pos,
2873				"DEVICE=%c%u:%u",
2874				c, MAJOR(dev->devt), MINOR(dev->devt));
2875	} else if (strcmp(subsys, "net") == 0) {
2876		struct net_device *net = to_net_dev(dev);
2877
2878		pos++;
2879		pos += snprintf(hdr + pos, hdrlen - pos,
2880				"DEVICE=n%u", net->ifindex);
2881	} else {
2882		pos++;
2883		pos += snprintf(hdr + pos, hdrlen - pos,
2884				"DEVICE=+%s:%s", subsys, dev_name(dev));
2885	}
2886
2887	if (pos >= hdrlen)
2888		goto overflow;
2889
2890	return pos;
2891
2892overflow:
2893	dev_WARN(dev, "device/subsystem name too long");
2894	return 0;
2895}
2896
2897int dev_vprintk_emit(int level, const struct device *dev,
2898		     const char *fmt, va_list args)
2899{
2900	char hdr[128];
2901	size_t hdrlen;
2902
2903	hdrlen = create_syslog_header(dev, hdr, sizeof(hdr));
2904
2905	return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen, fmt, args);
2906}
2907EXPORT_SYMBOL(dev_vprintk_emit);
2908
2909int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
2910{
2911	va_list args;
2912	int r;
2913
2914	va_start(args, fmt);
2915
2916	r = dev_vprintk_emit(level, dev, fmt, args);
2917
2918	va_end(args);
2919
2920	return r;
2921}
2922EXPORT_SYMBOL(dev_printk_emit);
2923
2924static void __dev_printk(const char *level, const struct device *dev,
2925			struct va_format *vaf)
2926{
2927	if (dev)
2928		dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
2929				dev_driver_string(dev), dev_name(dev), vaf);
2930	else
2931		printk("%s(NULL device *): %pV", level, vaf);
 
2932}
2933
2934void dev_printk(const char *level, const struct device *dev,
2935		const char *fmt, ...)
2936{
2937	struct va_format vaf;
2938	va_list args;
 
2939
2940	va_start(args, fmt);
2941
2942	vaf.fmt = fmt;
2943	vaf.va = &args;
2944
2945	__dev_printk(level, dev, &vaf);
2946
2947	va_end(args);
 
 
2948}
2949EXPORT_SYMBOL(dev_printk);
2950
2951#define define_dev_printk_level(func, kern_level)		\
2952void func(const struct device *dev, const char *fmt, ...)	\
2953{								\
2954	struct va_format vaf;					\
2955	va_list args;						\
 
2956								\
2957	va_start(args, fmt);					\
2958								\
2959	vaf.fmt = fmt;						\
2960	vaf.va = &args;						\
2961								\
2962	__dev_printk(kern_level, dev, &vaf);			\
2963								\
2964	va_end(args);						\
 
 
2965}								\
2966EXPORT_SYMBOL(func);
2967
2968define_dev_printk_level(dev_emerg, KERN_EMERG);
2969define_dev_printk_level(dev_alert, KERN_ALERT);
2970define_dev_printk_level(dev_crit, KERN_CRIT);
2971define_dev_printk_level(dev_err, KERN_ERR);
2972define_dev_printk_level(dev_warn, KERN_WARNING);
2973define_dev_printk_level(dev_notice, KERN_NOTICE);
2974define_dev_printk_level(_dev_info, KERN_INFO);
2975
2976#endif
2977
2978static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
2979{
2980	return fwnode && !IS_ERR(fwnode->secondary);
2981}
2982
2983/**
2984 * set_primary_fwnode - Change the primary firmware node of a given device.
2985 * @dev: Device to handle.
2986 * @fwnode: New primary firmware node of the device.
2987 *
2988 * Set the device's firmware node pointer to @fwnode, but if a secondary
2989 * firmware node of the device is present, preserve it.
2990 */
2991void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
2992{
2993	if (fwnode) {
2994		struct fwnode_handle *fn = dev->fwnode;
2995
2996		if (fwnode_is_primary(fn))
2997			fn = fn->secondary;
2998
2999		if (fn) {
3000			WARN_ON(fwnode->secondary);
3001			fwnode->secondary = fn;
3002		}
3003		dev->fwnode = fwnode;
3004	} else {
3005		dev->fwnode = fwnode_is_primary(dev->fwnode) ?
3006			dev->fwnode->secondary : NULL;
3007	}
3008}
3009EXPORT_SYMBOL_GPL(set_primary_fwnode);
3010
3011/**
3012 * set_secondary_fwnode - Change the secondary firmware node of a given device.
3013 * @dev: Device to handle.
3014 * @fwnode: New secondary firmware node of the device.
3015 *
3016 * If a primary firmware node of the device is present, set its secondary
3017 * pointer to @fwnode.  Otherwise, set the device's firmware node pointer to
3018 * @fwnode.
3019 */
3020void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
3021{
3022	if (fwnode)
3023		fwnode->secondary = ERR_PTR(-ENODEV);
3024
3025	if (fwnode_is_primary(dev->fwnode))
3026		dev->fwnode->secondary = fwnode;
3027	else
3028		dev->fwnode = fwnode;
3029}
3030
3031/**
3032 * device_set_of_node_from_dev - reuse device-tree node of another device
3033 * @dev: device whose device-tree node is being set
3034 * @dev2: device whose device-tree node is being reused
3035 *
3036 * Takes another reference to the new device-tree node after first dropping
3037 * any reference held to the old node.
3038 */
3039void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
3040{
3041	of_node_put(dev->of_node);
3042	dev->of_node = of_node_get(dev2->of_node);
3043	dev->of_node_reused = true;
3044}
3045EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);