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Greg Kroah-Hartman989d42e2017-11-07 17:30:07 +01001// SPDX-License-Identifier: GPL-2.0
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
3 * bus.c - bus driver management
4 *
5 * Copyright (c) 2002-3 Patrick Mochel
6 * Copyright (c) 2002-3 Open Source Development Labs
Greg Kroah-Hartmane5dd1272007-11-28 15:59:15 -08007 * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de>
8 * Copyright (c) 2007 Novell Inc.
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 */
10
Dmitry Torokhov765230b2015-03-30 16:20:04 -070011#include <linux/async.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/device.h>
13#include <linux/module.h>
14#include <linux/errno.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090015#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/init.h>
17#include <linux/string.h>
Kay Sieversca22e562011-12-14 14:29:38 -080018#include <linux/mutex.h>
Greg Kroah-Hartman63967682013-08-27 10:24:15 -070019#include <linux/sysfs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include "base.h"
21#include "power/power.h"
22
Kay Sieversca22e562011-12-14 14:29:38 -080023/* /sys/devices/system */
H Hartley Sweeten97ec4482012-04-16 18:14:10 -070024static struct kset *system_kset;
Kay Sieversca22e562011-12-14 14:29:38 -080025
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
28/*
29 * sysfs bindings for drivers
30 */
31
32#define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
Daniel Vetter4f4b3742018-12-19 13:39:09 +010034#define DRIVER_ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) \
35 struct driver_attribute driver_attr_##_name = \
36 __ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store)
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
Kay Sieversb8c5cec2007-02-16 17:33:36 +010038static int __must_check bus_rescan_devices_helper(struct device *dev,
39 void *data);
40
Greg Kroah-Hartman5901d012007-09-13 02:53:13 -070041static struct bus_type *bus_get(struct bus_type *bus)
42{
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -070043 if (bus) {
44 kset_get(&bus->p->subsys);
45 return bus;
46 }
47 return NULL;
Greg Kroah-Hartman5901d012007-09-13 02:53:13 -070048}
49
Greg Kroah-Hartmanfc1ede52007-09-13 02:53:13 -070050static void bus_put(struct bus_type *bus)
51{
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -070052 if (bus)
53 kset_put(&bus->p->subsys);
Greg Kroah-Hartmanfc1ede52007-09-13 02:53:13 -070054}
55
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -080056static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr,
57 char *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -070058{
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -080059 struct driver_attribute *drv_attr = to_drv_attr(attr);
Greg Kroah-Hartmane5dd1272007-11-28 15:59:15 -080060 struct driver_private *drv_priv = to_driver(kobj);
Dmitry Torokhov4a0c20b2005-04-29 01:23:47 -050061 ssize_t ret = -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63 if (drv_attr->show)
Greg Kroah-Hartmane5dd1272007-11-28 15:59:15 -080064 ret = drv_attr->show(drv_priv->driver, buf);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065 return ret;
66}
67
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -080068static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr,
69 const char *buf, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -070070{
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -080071 struct driver_attribute *drv_attr = to_drv_attr(attr);
Greg Kroah-Hartmane5dd1272007-11-28 15:59:15 -080072 struct driver_private *drv_priv = to_driver(kobj);
Dmitry Torokhov4a0c20b2005-04-29 01:23:47 -050073 ssize_t ret = -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -070074
75 if (drv_attr->store)
Greg Kroah-Hartmane5dd1272007-11-28 15:59:15 -080076 ret = drv_attr->store(drv_priv->driver, buf, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 return ret;
78}
79
Emese Revfy52cf25d2010-01-19 02:58:23 +010080static const struct sysfs_ops driver_sysfs_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070081 .show = drv_attr_show,
82 .store = drv_attr_store,
83};
84
Greg Kroah-Hartmane5dd1272007-11-28 15:59:15 -080085static void driver_release(struct kobject *kobj)
Linus Torvalds1da177e2005-04-16 15:20:36 -070086{
Greg Kroah-Hartmane5dd1272007-11-28 15:59:15 -080087 struct driver_private *drv_priv = to_driver(kobj);
88
Harvey Harrison2b3a3022008-03-04 16:41:05 -080089 pr_debug("driver: '%s': %s\n", kobject_name(kobj), __func__);
Greg Kroah-Hartmane5dd1272007-11-28 15:59:15 -080090 kfree(drv_priv);
Linus Torvalds1da177e2005-04-16 15:20:36 -070091}
92
Greg Kroah-Hartmana1148fb2007-10-11 10:47:49 -060093static struct kobj_type driver_ktype = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 .sysfs_ops = &driver_sysfs_ops,
95 .release = driver_release,
96};
97
Linus Torvalds1da177e2005-04-16 15:20:36 -070098/*
99 * sysfs bindings for buses
100 */
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800101static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr,
102 char *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103{
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800104 struct bus_attribute *bus_attr = to_bus_attr(attr);
Kay Sievers6b6e39a2010-11-15 23:13:18 +0100105 struct subsys_private *subsys_priv = to_subsys_private(kobj);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 ssize_t ret = 0;
107
108 if (bus_attr->show)
Kay Sievers6b6e39a2010-11-15 23:13:18 +0100109 ret = bus_attr->show(subsys_priv->bus, buf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 return ret;
111}
112
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800113static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr,
114 const char *buf, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115{
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800116 struct bus_attribute *bus_attr = to_bus_attr(attr);
Kay Sievers6b6e39a2010-11-15 23:13:18 +0100117 struct subsys_private *subsys_priv = to_subsys_private(kobj);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 ssize_t ret = 0;
119
120 if (bus_attr->store)
Kay Sievers6b6e39a2010-11-15 23:13:18 +0100121 ret = bus_attr->store(subsys_priv->bus, buf, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 return ret;
123}
124
Emese Revfy52cf25d2010-01-19 02:58:23 +0100125static const struct sysfs_ops bus_sysfs_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 .show = bus_attr_show,
127 .store = bus_attr_store,
128};
129
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800130int bus_create_file(struct bus_type *bus, struct bus_attribute *attr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131{
132 int error;
Greg Kroah-Hartman5901d012007-09-13 02:53:13 -0700133 if (bus_get(bus)) {
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700134 error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr);
Greg Kroah-Hartmanfc1ede52007-09-13 02:53:13 -0700135 bus_put(bus);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 } else
137 error = -EINVAL;
138 return error;
139}
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800140EXPORT_SYMBOL_GPL(bus_create_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800142void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143{
Greg Kroah-Hartman5901d012007-09-13 02:53:13 -0700144 if (bus_get(bus)) {
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700145 sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr);
Greg Kroah-Hartmanfc1ede52007-09-13 02:53:13 -0700146 bus_put(bus);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 }
148}
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800149EXPORT_SYMBOL_GPL(bus_remove_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150
Bart Van Assche174be702014-01-04 14:21:42 +0100151static void bus_release(struct kobject *kobj)
152{
Geliang Tang371fd7a2016-01-05 23:03:38 +0800153 struct subsys_private *priv = to_subsys_private(kobj);
Bart Van Assche174be702014-01-04 14:21:42 +0100154 struct bus_type *bus = priv->bus;
155
156 kfree(priv);
157 bus->p = NULL;
158}
159
Kay Sievers80f03e32007-05-26 11:21:36 +0200160static struct kobj_type bus_ktype = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 .sysfs_ops = &bus_sysfs_ops,
Bart Van Assche174be702014-01-04 14:21:42 +0100162 .release = bus_release,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163};
164
Kay Sievers80f03e32007-05-26 11:21:36 +0200165static int bus_uevent_filter(struct kset *kset, struct kobject *kobj)
166{
167 struct kobj_type *ktype = get_ktype(kobj);
168
169 if (ktype == &bus_ktype)
170 return 1;
171 return 0;
172}
173
Emese Revfy9cd43612009-12-31 14:52:51 +0100174static const struct kset_uevent_ops bus_uevent_ops = {
Kay Sievers80f03e32007-05-26 11:21:36 +0200175 .filter = bus_uevent_filter,
176};
177
Greg Kroah-Hartman59a54832007-10-29 23:22:26 -0500178static struct kset *bus_kset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179
Alan Stern2b08c8d2005-11-23 15:43:50 -0800180/* Manually detach a device from its associated driver. */
Greg Kroah-Hartman2581c9c2013-08-23 15:04:42 -0700181static ssize_t unbind_store(struct device_driver *drv, const char *buf,
182 size_t count)
Greg Kroah-Hartman151ef382005-06-22 16:09:05 -0700183{
Greg Kroah-Hartman5901d012007-09-13 02:53:13 -0700184 struct bus_type *bus = bus_get(drv->bus);
Greg Kroah-Hartman151ef382005-06-22 16:09:05 -0700185 struct device *dev;
186 int err = -ENODEV;
187
Greg Kroah-Hartman1f9ffc02008-01-27 10:29:20 -0800188 dev = bus_find_device_by_name(bus, NULL, buf);
Alan Stern2b08c8d2005-11-23 15:43:50 -0800189 if (dev && dev->driver == drv) {
Alexander Duycked887472019-01-22 10:39:16 -0800190 device_driver_detach(dev);
Greg Kroah-Hartman151ef382005-06-22 16:09:05 -0700191 err = count;
192 }
Alan Stern2b08c8d2005-11-23 15:43:50 -0800193 put_device(dev);
Greg Kroah-Hartmanfc1ede52007-09-13 02:53:13 -0700194 bus_put(bus);
Alan Stern2b08c8d2005-11-23 15:43:50 -0800195 return err;
Greg Kroah-Hartman151ef382005-06-22 16:09:05 -0700196}
Daniel Vetter4f4b3742018-12-19 13:39:09 +0100197static DRIVER_ATTR_IGNORE_LOCKDEP(unbind, S_IWUSR, NULL, unbind_store);
Greg Kroah-Hartman151ef382005-06-22 16:09:05 -0700198
Greg Kroah-Hartmanafdce752005-06-22 16:09:05 -0700199/*
200 * Manually attach a device to a driver.
201 * Note: the driver must want to bind to the device,
202 * it is not possible to override the driver's id table.
203 */
Greg Kroah-Hartman2581c9c2013-08-23 15:04:42 -0700204static ssize_t bind_store(struct device_driver *drv, const char *buf,
205 size_t count)
Greg Kroah-Hartmanafdce752005-06-22 16:09:05 -0700206{
Greg Kroah-Hartman5901d012007-09-13 02:53:13 -0700207 struct bus_type *bus = bus_get(drv->bus);
Greg Kroah-Hartmanafdce752005-06-22 16:09:05 -0700208 struct device *dev;
209 int err = -ENODEV;
210
Greg Kroah-Hartman1f9ffc02008-01-27 10:29:20 -0800211 dev = bus_find_device_by_name(bus, NULL, buf);
Ming Lei49b420a2009-01-21 23:27:47 +0800212 if (dev && dev->driver == NULL && driver_match_device(drv, dev)) {
Alexander Duycked887472019-01-22 10:39:16 -0800213 err = device_driver_attach(drv, dev);
Ryan Wilson37225402006-03-22 16:26:25 -0500214
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800215 if (err > 0) {
216 /* success */
Ryan Wilson37225402006-03-22 16:26:25 -0500217 err = count;
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800218 } else if (err == 0) {
219 /* driver didn't accept device */
Ryan Wilson37225402006-03-22 16:26:25 -0500220 err = -ENODEV;
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800221 }
Greg Kroah-Hartmanafdce752005-06-22 16:09:05 -0700222 }
Alan Stern2b08c8d2005-11-23 15:43:50 -0800223 put_device(dev);
Greg Kroah-Hartmanfc1ede52007-09-13 02:53:13 -0700224 bus_put(bus);
Alan Stern2b08c8d2005-11-23 15:43:50 -0800225 return err;
Greg Kroah-Hartmanafdce752005-06-22 16:09:05 -0700226}
Daniel Vetter4f4b3742018-12-19 13:39:09 +0100227static DRIVER_ATTR_IGNORE_LOCKDEP(bind, S_IWUSR, NULL, bind_store);
Greg Kroah-Hartmanafdce752005-06-22 16:09:05 -0700228
Greg Kroah-Hartman2e7189b2018-07-12 09:33:17 +0200229static ssize_t drivers_autoprobe_show(struct bus_type *bus, char *buf)
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100230{
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700231 return sprintf(buf, "%d\n", bus->p->drivers_autoprobe);
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100232}
233
Greg Kroah-Hartman2e7189b2018-07-12 09:33:17 +0200234static ssize_t drivers_autoprobe_store(struct bus_type *bus,
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100235 const char *buf, size_t count)
236{
237 if (buf[0] == '0')
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700238 bus->p->drivers_autoprobe = 0;
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100239 else
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700240 bus->p->drivers_autoprobe = 1;
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100241 return count;
242}
243
Greg Kroah-Hartman2e7189b2018-07-12 09:33:17 +0200244static ssize_t drivers_probe_store(struct bus_type *bus,
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100245 const char *buf, size_t count)
246{
247 struct device *dev;
Alex Williamson0372ffb2014-10-31 11:13:07 -0600248 int err = -EINVAL;
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100249
Greg Kroah-Hartman1f9ffc02008-01-27 10:29:20 -0800250 dev = bus_find_device_by_name(bus, NULL, buf);
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100251 if (!dev)
252 return -ENODEV;
Alex Williamson0372ffb2014-10-31 11:13:07 -0600253 if (bus_rescan_devices_helper(dev, NULL) == 0)
254 err = count;
255 put_device(dev);
256 return err;
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100257}
Greg Kroah-Hartman151ef382005-06-22 16:09:05 -0700258
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800259static struct device *next_device(struct klist_iter *i)
mochel@digitalimplant.org465c7a32005-03-21 11:49:14 -0800260{
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800261 struct klist_node *n = klist_next(i);
Greg Kroah-Hartmanae1b4172008-12-16 12:26:21 -0800262 struct device *dev = NULL;
263 struct device_private *dev_prv;
264
265 if (n) {
266 dev_prv = to_device_private_bus(n);
267 dev = dev_prv->device;
268 }
269 return dev;
mochel@digitalimplant.org465c7a32005-03-21 11:49:14 -0800270}
271
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272/**
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800273 * bus_for_each_dev - device iterator.
274 * @bus: bus type.
275 * @start: device to start iterating from.
276 * @data: data for the callback.
277 * @fn: function to be called for each device.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 *
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800279 * Iterate over @bus's list of devices, and call @fn for each,
280 * passing it @data. If @start is not NULL, we use that device to
281 * begin iterating from.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282 *
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800283 * We check the return of @fn each time. If it returns anything
284 * other than 0, we break out and return that value.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285 *
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800286 * NOTE: The device that returns a non-zero value is not retained
287 * in any way, nor is its refcount incremented. If the caller needs
Alex Chiang0fa1b0a2009-05-14 23:15:22 +0200288 * to retain this data, it should do so, and increment the reference
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800289 * count in the supplied callback.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 */
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800291int bus_for_each_dev(struct bus_type *bus, struct device *start,
292 void *data, int (*fn)(struct device *, void *))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293{
mochel@digitalimplant.org465c7a32005-03-21 11:49:14 -0800294 struct klist_iter i;
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800295 struct device *dev;
mochel@digitalimplant.org465c7a32005-03-21 11:49:14 -0800296 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297
Bjorn Helgaas4fa3e782013-01-29 16:44:27 -0700298 if (!bus || !bus->p)
mochel@digitalimplant.org465c7a32005-03-21 11:49:14 -0800299 return -EINVAL;
300
Greg Kroah-Hartman7cd9c9b2012-04-19 19:17:30 -0700301 klist_iter_init_node(&bus->p->klist_devices, &i,
302 (start ? &start->p->knode_bus : NULL));
Gimcuan Hui93ead7c2017-11-11 05:52:54 +0000303 while (!error && (dev = next_device(&i)))
Greg Kroah-Hartman7cd9c9b2012-04-19 19:17:30 -0700304 error = fn(dev, data);
305 klist_iter_exit(&i);
mochel@digitalimplant.org465c7a32005-03-21 11:49:14 -0800306 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307}
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800308EXPORT_SYMBOL_GPL(bus_for_each_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309
Cornelia Huck0edb5862005-06-22 16:59:51 +0200310/**
311 * bus_find_device - device iterator for locating a particular device.
312 * @bus: bus type
313 * @start: Device to begin with
314 * @data: Data to pass to match function
315 * @match: Callback function to check device
316 *
317 * This is similar to the bus_for_each_dev() function above, but it
318 * returns a reference to a device that is 'found' for later use, as
319 * determined by the @match callback.
320 *
321 * The callback should return 0 if the device doesn't match and non-zero
322 * if it does. If the callback returns non-zero, this function will
323 * return to the caller and not iterate over any more devices.
324 */
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800325struct device *bus_find_device(struct bus_type *bus,
Suzuki K Poulose418e3ea2019-06-14 18:53:59 +0100326 struct device *start, const void *data,
327 int (*match)(struct device *dev, const void *data))
Cornelia Huck0edb5862005-06-22 16:59:51 +0200328{
329 struct klist_iter i;
330 struct device *dev;
331
Bjorn Helgaas4fa3e782013-01-29 16:44:27 -0700332 if (!bus || !bus->p)
Cornelia Huck0edb5862005-06-22 16:59:51 +0200333 return NULL;
334
Greg Kroah-Hartman7cd9c9b2012-04-19 19:17:30 -0700335 klist_iter_init_node(&bus->p->klist_devices, &i,
336 (start ? &start->p->knode_bus : NULL));
Cornelia Huck0edb5862005-06-22 16:59:51 +0200337 while ((dev = next_device(&i)))
338 if (match(dev, data) && get_device(dev))
339 break;
340 klist_iter_exit(&i);
341 return dev;
342}
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800343EXPORT_SYMBOL_GPL(bus_find_device);
mochel@digitalimplant.org38fdac32005-03-21 12:00:18 -0800344
Kay Sieversca22e562011-12-14 14:29:38 -0800345/**
346 * subsys_find_device_by_id - find a device with a specific enumeration number
347 * @subsys: subsystem
348 * @id: index 'id' in struct device
349 * @hint: device to check first
350 *
351 * Check the hint's next object and if it is a match return it directly,
352 * otherwise, fall back to a full list search. Either way a reference for
353 * the returned object is taken.
354 */
355struct device *subsys_find_device_by_id(struct bus_type *subsys, unsigned int id,
356 struct device *hint)
357{
358 struct klist_iter i;
359 struct device *dev;
360
361 if (!subsys)
362 return NULL;
363
364 if (hint) {
Greg Kroah-Hartman7cd9c9b2012-04-19 19:17:30 -0700365 klist_iter_init_node(&subsys->p->klist_devices, &i, &hint->p->knode_bus);
Kay Sieversca22e562011-12-14 14:29:38 -0800366 dev = next_device(&i);
367 if (dev && dev->id == id && get_device(dev)) {
368 klist_iter_exit(&i);
369 return dev;
370 }
371 klist_iter_exit(&i);
372 }
373
374 klist_iter_init_node(&subsys->p->klist_devices, &i, NULL);
375 while ((dev = next_device(&i))) {
376 if (dev->id == id && get_device(dev)) {
377 klist_iter_exit(&i);
378 return dev;
379 }
380 }
381 klist_iter_exit(&i);
382 return NULL;
383}
384EXPORT_SYMBOL_GPL(subsys_find_device_by_id);
385
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800386static struct device_driver *next_driver(struct klist_iter *i)
mochel@digitalimplant.org38fdac32005-03-21 12:00:18 -0800387{
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800388 struct klist_node *n = klist_next(i);
Greg Kroah-Hartmane5dd1272007-11-28 15:59:15 -0800389 struct driver_private *drv_priv;
390
391 if (n) {
392 drv_priv = container_of(n, struct driver_private, knode_bus);
393 return drv_priv->driver;
394 }
395 return NULL;
mochel@digitalimplant.org38fdac32005-03-21 12:00:18 -0800396}
397
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398/**
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800399 * bus_for_each_drv - driver iterator
400 * @bus: bus we're dealing with.
401 * @start: driver to start iterating on.
402 * @data: data to pass to the callback.
403 * @fn: function to call for each driver.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 *
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800405 * This is nearly identical to the device iterator above.
406 * We iterate over each driver that belongs to @bus, and call
407 * @fn for each. If @fn returns anything but 0, we break out
408 * and return it. If @start is not NULL, we use it as the head
409 * of the list.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410 *
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800411 * NOTE: we don't return the driver that returns a non-zero
412 * value, nor do we leave the reference count incremented for that
413 * driver. If the caller needs to know that info, it must set it
414 * in the callback. It must also be sure to increment the refcount
415 * so it doesn't disappear before returning to the caller.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 */
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800417int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
418 void *data, int (*fn)(struct device_driver *, void *))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419{
mochel@digitalimplant.org38fdac32005-03-21 12:00:18 -0800420 struct klist_iter i;
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800421 struct device_driver *drv;
mochel@digitalimplant.org38fdac32005-03-21 12:00:18 -0800422 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423
mochel@digitalimplant.org38fdac32005-03-21 12:00:18 -0800424 if (!bus)
425 return -EINVAL;
426
Greg Kroah-Hartman7cd9c9b2012-04-19 19:17:30 -0700427 klist_iter_init_node(&bus->p->klist_drivers, &i,
428 start ? &start->p->knode_bus : NULL);
429 while ((drv = next_driver(&i)) && !error)
430 error = fn(drv, data);
431 klist_iter_exit(&i);
mochel@digitalimplant.org38fdac32005-03-21 12:00:18 -0800432 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433}
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800434EXPORT_SYMBOL_GPL(bus_for_each_drv);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436/**
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800437 * bus_add_device - add device to bus
438 * @dev: device being added
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 *
Alan Stern2023c612009-07-30 15:27:18 -0400440 * - Add device's bus attributes.
441 * - Create links to device's bus.
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800442 * - Add the device to its bus's list of devices.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443 */
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800444int bus_add_device(struct device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445{
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800446 struct bus_type *bus = bus_get(dev->bus);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 int error = 0;
448
449 if (bus) {
Kay Sievers1e0b2cf2008-10-30 01:36:48 +0100450 pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev));
Greg Kroah-Hartmanfa6fdb32013-08-08 15:22:55 -0700451 error = device_add_groups(dev, bus->dev_groups);
452 if (error)
Greg Kroah-Hartmanb46c7332013-08-23 14:12:09 -0700453 goto out_put;
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700454 error = sysfs_create_link(&bus->p->devices_kset->kobj,
Kay Sievers1e0b2cf2008-10-30 01:36:48 +0100455 &dev->kobj, dev_name(dev));
Andrew Mortonf86db392006-08-14 22:43:20 -0700456 if (error)
Junjie Mao1c342032015-01-28 10:02:44 +0800457 goto out_groups;
Andrew Mortonf86db392006-08-14 22:43:20 -0700458 error = sysfs_create_link(&dev->kobj,
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700459 &dev->bus->p->subsys.kobj, "subsystem");
Andrew Mortonf86db392006-08-14 22:43:20 -0700460 if (error)
Cornelia Huck513e7332006-09-22 11:37:08 +0200461 goto out_subsys;
Alan Stern2023c612009-07-30 15:27:18 -0400462 klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 }
Cornelia Huck513e7332006-09-22 11:37:08 +0200464 return 0;
465
Cornelia Huck513e7332006-09-22 11:37:08 +0200466out_subsys:
Kay Sievers1e0b2cf2008-10-30 01:36:48 +0100467 sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev));
Greg Kroah-Hartmanfa6fdb32013-08-08 15:22:55 -0700468out_groups:
469 device_remove_groups(dev, bus->dev_groups);
Cornelia Huck513e7332006-09-22 11:37:08 +0200470out_put:
Greg Kroah-Hartmanfc1ede52007-09-13 02:53:13 -0700471 bus_put(dev->bus);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 return error;
473}
474
475/**
Alan Stern2023c612009-07-30 15:27:18 -0400476 * bus_probe_device - probe drivers for a new device
477 * @dev: device to probe
Kay Sievers53877d02006-04-04 20:42:26 +0200478 *
Alan Stern2023c612009-07-30 15:27:18 -0400479 * - Automatically probe for a driver if the bus allows it.
Kay Sievers53877d02006-04-04 20:42:26 +0200480 */
Alan Stern2023c612009-07-30 15:27:18 -0400481void bus_probe_device(struct device *dev)
Kay Sievers53877d02006-04-04 20:42:26 +0200482{
Andrew Mortonf86db392006-08-14 22:43:20 -0700483 struct bus_type *bus = dev->bus;
Kay Sieversca22e562011-12-14 14:29:38 -0800484 struct subsys_interface *sif;
Kay Sievers53877d02006-04-04 20:42:26 +0200485
Kay Sieversca22e562011-12-14 14:29:38 -0800486 if (!bus)
487 return;
488
Dmitry Torokhov765230b2015-03-30 16:20:04 -0700489 if (bus->p->drivers_autoprobe)
490 device_initial_probe(dev);
Kay Sieversca22e562011-12-14 14:29:38 -0800491
492 mutex_lock(&bus->p->mutex);
493 list_for_each_entry(sif, &bus->p->interfaces, node)
494 if (sif->add_dev)
495 sif->add_dev(dev, sif);
496 mutex_unlock(&bus->p->mutex);
Kay Sievers53877d02006-04-04 20:42:26 +0200497}
498
499/**
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800500 * bus_remove_device - remove device from bus
501 * @dev: device to be removed
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502 *
Kay Sieversca22e562011-12-14 14:29:38 -0800503 * - Remove device from all interfaces.
504 * - Remove symlink from bus' directory.
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800505 * - Delete device from bus's list.
506 * - Detach from its driver.
507 * - Drop reference taken in bus_add_device().
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 */
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800509void bus_remove_device(struct device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510{
Kay Sieversca22e562011-12-14 14:29:38 -0800511 struct bus_type *bus = dev->bus;
512 struct subsys_interface *sif;
Greg Kroah-Hartman3f62e572008-03-13 17:07:03 -0400513
Kay Sieversca22e562011-12-14 14:29:38 -0800514 if (!bus)
515 return;
516
517 mutex_lock(&bus->p->mutex);
518 list_for_each_entry(sif, &bus->p->interfaces, node)
519 if (sif->remove_dev)
520 sif->remove_dev(dev, sif);
521 mutex_unlock(&bus->p->mutex);
522
523 sysfs_remove_link(&dev->kobj, "subsystem");
524 sysfs_remove_link(&dev->bus->p->devices_kset->kobj,
525 dev_name(dev));
Greg Kroah-Hartmanfa6fdb32013-08-08 15:22:55 -0700526 device_remove_groups(dev, dev->bus->dev_groups);
Kay Sieversca22e562011-12-14 14:29:38 -0800527 if (klist_node_attached(&dev->p->knode_bus))
528 klist_del(&dev->p->knode_bus);
529
530 pr_debug("bus: '%s': remove device %s\n",
531 dev->bus->name, dev_name(dev));
532 device_release_driver(dev);
533 bus_put(dev->bus);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534}
535
Andrew Mortonf86db392006-08-14 22:43:20 -0700536static int __must_check add_bind_files(struct device_driver *drv)
Greg Kroah-Hartman874c6242005-12-13 15:17:34 -0800537{
Andrew Mortonf86db392006-08-14 22:43:20 -0700538 int ret;
539
540 ret = driver_create_file(drv, &driver_attr_unbind);
541 if (ret == 0) {
542 ret = driver_create_file(drv, &driver_attr_bind);
543 if (ret)
544 driver_remove_file(drv, &driver_attr_unbind);
545 }
546 return ret;
Greg Kroah-Hartman874c6242005-12-13 15:17:34 -0800547}
548
549static void remove_bind_files(struct device_driver *drv)
550{
551 driver_remove_file(drv, &driver_attr_bind);
552 driver_remove_file(drv, &driver_attr_unbind);
553}
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100554
Greg Kroah-Hartman2e7189b2018-07-12 09:33:17 +0200555static BUS_ATTR_WO(drivers_probe);
556static BUS_ATTR_RW(drivers_autoprobe);
Kay Sievers83807702007-07-30 02:28:56 +0200557
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100558static int add_probe_files(struct bus_type *bus)
559{
560 int retval;
561
Kay Sievers83807702007-07-30 02:28:56 +0200562 retval = bus_create_file(bus, &bus_attr_drivers_probe);
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100563 if (retval)
564 goto out;
565
Kay Sievers83807702007-07-30 02:28:56 +0200566 retval = bus_create_file(bus, &bus_attr_drivers_autoprobe);
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100567 if (retval)
Kay Sievers83807702007-07-30 02:28:56 +0200568 bus_remove_file(bus, &bus_attr_drivers_probe);
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100569out:
570 return retval;
571}
572
573static void remove_probe_files(struct bus_type *bus)
574{
Kay Sievers83807702007-07-30 02:28:56 +0200575 bus_remove_file(bus, &bus_attr_drivers_autoprobe);
576 bus_remove_file(bus, &bus_attr_drivers_probe);
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100577}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578
Greg Kroah-Hartman2581c9c2013-08-23 15:04:42 -0700579static ssize_t uevent_store(struct device_driver *drv, const char *buf,
580 size_t count)
Kay Sievers7ac1cf42007-08-12 20:43:55 +0200581{
Peter Rajnohadf44b472018-12-05 12:27:44 +0100582 int rc;
583
584 rc = kobject_synth_uevent(&drv->p->kobj, buf, count);
585 return rc ? rc : count;
Kay Sievers7ac1cf42007-08-12 20:43:55 +0200586}
Greg Kroah-Hartman2581c9c2013-08-23 15:04:42 -0700587static DRIVER_ATTR_WO(uevent);
Kay Sievers7ac1cf42007-08-12 20:43:55 +0200588
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589/**
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800590 * bus_add_driver - Add a driver to the bus.
591 * @drv: driver.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 */
Andrew Mortonf86db392006-08-14 22:43:20 -0700593int bus_add_driver(struct device_driver *drv)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594{
Greg Kroah-Hartmane5dd1272007-11-28 15:59:15 -0800595 struct bus_type *bus;
596 struct driver_private *priv;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597 int error = 0;
598
Greg Kroah-Hartmane5dd1272007-11-28 15:59:15 -0800599 bus = bus_get(drv->bus);
Jeff Garzikd9fd4d3b32006-10-04 07:48:03 -0400600 if (!bus)
Greg Kroah-Hartman4f6e1942007-04-20 11:29:52 -0700601 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602
Greg Kroah-Hartman7dc72b22007-11-28 23:49:41 -0800603 pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name);
Greg Kroah-Hartmane5dd1272007-11-28 15:59:15 -0800604
605 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
Cornelia Huck07634462008-02-18 17:04:25 +0100606 if (!priv) {
607 error = -ENOMEM;
608 goto out_put_bus;
609 }
Greg Kroah-Hartmane5dd1272007-11-28 15:59:15 -0800610 klist_init(&priv->klist_devices, NULL, NULL);
611 priv->driver = drv;
612 drv->p = priv;
Greg Kroah-Hartmanc8e90d82007-12-17 15:54:39 -0400613 priv->kobj.kset = bus->p->drivers_kset;
614 error = kobject_init_and_add(&priv->kobj, &driver_ktype, NULL,
615 "%s", drv->name);
Cornelia Huckdc0afa82007-07-09 11:39:18 -0700616 if (error)
Cornelia Huck07634462008-02-18 17:04:25 +0100617 goto out_unregister;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618
Ming Lei190888a2012-11-19 23:35:17 +0800619 klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers);
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700620 if (drv->bus->p->drivers_autoprobe) {
Alexander Duyckef0ff682019-01-22 10:39:21 -0800621 error = driver_attach(drv);
622 if (error)
623 goto out_unregister;
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100624 }
Jeff Garzikd9fd4d3b32006-10-04 07:48:03 -0400625 module_add_driver(drv->owner, drv);
626
Kay Sievers7ac1cf42007-08-12 20:43:55 +0200627 error = driver_create_file(drv, &driver_attr_uevent);
628 if (error) {
629 printk(KERN_ERR "%s: uevent attr (%s) failed\n",
Harvey Harrison2b3a3022008-03-04 16:41:05 -0800630 __func__, drv->name);
Kay Sievers7ac1cf42007-08-12 20:43:55 +0200631 }
Greg Kroah-Hartmane18945b2013-09-27 21:47:21 -0700632 error = driver_add_groups(drv, bus->drv_groups);
Jeff Garzikd9fd4d3b32006-10-04 07:48:03 -0400633 if (error) {
634 /* How the hell do we get out of this pickle? Give up */
Greg Kroah-Hartmaned0617b2013-08-08 15:22:56 -0700635 printk(KERN_ERR "%s: driver_create_groups(%s) failed\n",
636 __func__, drv->name);
Greg Kroah-Hartmane18945b2013-09-27 21:47:21 -0700637 }
Dmitry Torokhov1a6f2a72009-10-12 20:17:41 -0700638
639 if (!drv->suppress_bind_attrs) {
640 error = add_bind_files(drv);
641 if (error) {
642 /* Ditto */
643 printk(KERN_ERR "%s: add_bind_files(%s) failed\n",
644 __func__, drv->name);
645 }
Jeff Garzikd9fd4d3b32006-10-04 07:48:03 -0400646 }
647
Kay Sievers5c8563d2009-05-28 14:24:07 -0700648 return 0;
Dmitry Torokhov1a6f2a72009-10-12 20:17:41 -0700649
Andrew Mortonf86db392006-08-14 22:43:20 -0700650out_unregister:
Phil Carmody99b28f12009-12-14 20:28:12 +0200651 kobject_put(&priv->kobj);
Christophe JAILLET0f9b0112017-08-29 21:23:49 +0200652 /* drv->p is freed in driver_release() */
Kay Sievers5c8563d2009-05-28 14:24:07 -0700653 drv->p = NULL;
Andrew Mortonf86db392006-08-14 22:43:20 -0700654out_put_bus:
Greg Kroah-Hartmanfc1ede52007-09-13 02:53:13 -0700655 bus_put(bus);
Andrew Mortonf86db392006-08-14 22:43:20 -0700656 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657}
658
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659/**
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800660 * bus_remove_driver - delete driver from bus's knowledge.
661 * @drv: driver.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 *
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800663 * Detach the driver from the devices it controls, and remove
664 * it from its bus's list of drivers. Finally, we drop the reference
665 * to the bus we took in bus_add_driver().
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 */
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800667void bus_remove_driver(struct device_driver *drv)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668{
Jeff Garzikd9fd4d3b32006-10-04 07:48:03 -0400669 if (!drv->bus)
670 return;
671
Dmitry Torokhov1a6f2a72009-10-12 20:17:41 -0700672 if (!drv->suppress_bind_attrs)
673 remove_bind_files(drv);
Greg Kroah-Hartmaned0617b2013-08-08 15:22:56 -0700674 driver_remove_groups(drv, drv->bus->drv_groups);
Kay Sievers7ac1cf42007-08-12 20:43:55 +0200675 driver_remove_file(drv, &driver_attr_uevent);
Greg Kroah-Hartmane5dd1272007-11-28 15:59:15 -0800676 klist_remove(&drv->p->knode_bus);
Greg Kroah-Hartman7dc72b22007-11-28 23:49:41 -0800677 pr_debug("bus: '%s': remove driver %s\n", drv->bus->name, drv->name);
Jeff Garzikd9fd4d3b32006-10-04 07:48:03 -0400678 driver_detach(drv);
679 module_remove_driver(drv);
Greg Kroah-Hartmanc10997f2007-12-20 08:13:05 -0800680 kobject_put(&drv->p->kobj);
Greg Kroah-Hartmanfc1ede52007-09-13 02:53:13 -0700681 bus_put(drv->bus);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682}
683
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684/* Helper for bus_rescan_devices's iter */
Andrew Mortonf86db392006-08-14 22:43:20 -0700685static int __must_check bus_rescan_devices_helper(struct device *dev,
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800686 void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687{
Andrew Mortonf86db392006-08-14 22:43:20 -0700688 int ret = 0;
689
Alan Sternbf74ad52005-11-17 16:54:12 -0500690 if (!dev->driver) {
Martin Liu8c97a462018-05-31 00:31:36 +0800691 if (dev->parent && dev->bus->need_parent_lock)
Greg Kroah-Hartman8e9394c2010-02-17 10:57:05 -0800692 device_lock(dev->parent);
Andrew Mortonf86db392006-08-14 22:43:20 -0700693 ret = device_attach(dev);
Martin Liu8c97a462018-05-31 00:31:36 +0800694 if (dev->parent && dev->bus->need_parent_lock)
Greg Kroah-Hartman8e9394c2010-02-17 10:57:05 -0800695 device_unlock(dev->parent);
Alan Sternbf74ad52005-11-17 16:54:12 -0500696 }
Andrew Mortonf86db392006-08-14 22:43:20 -0700697 return ret < 0 ? ret : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698}
699
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700/**
Greg Kroah-Hartman23d3d602005-06-22 16:09:05 -0700701 * bus_rescan_devices - rescan devices on the bus for possible drivers
702 * @bus: the bus to scan.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 *
Greg Kroah-Hartman23d3d602005-06-22 16:09:05 -0700704 * This function will look for devices on the bus with no driver
705 * attached and rescan it against existing drivers to see if it matches
706 * any by calling device_attach() for the unbound devices.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 */
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800708int bus_rescan_devices(struct bus_type *bus)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709{
Andrew Mortonf86db392006-08-14 22:43:20 -0700710 return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711}
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800712EXPORT_SYMBOL_GPL(bus_rescan_devices);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713
Moore, Erice935d5d2006-03-14 09:18:18 -0700714/**
715 * device_reprobe - remove driver for a device and probe for a new driver
716 * @dev: the device to reprobe
717 *
718 * This function detaches the attached driver (if any) for the given
719 * device and restarts the driver probing process. It is intended
720 * to use if probing criteria changed during a devices lifetime and
721 * driver attachment should change accordingly.
722 */
Andrew Mortonf86db392006-08-14 22:43:20 -0700723int device_reprobe(struct device *dev)
Moore, Erice935d5d2006-03-14 09:18:18 -0700724{
Alexander Duycked887472019-01-22 10:39:16 -0800725 if (dev->driver)
726 device_driver_detach(dev);
Andrew Mortonf86db392006-08-14 22:43:20 -0700727 return bus_rescan_devices_helper(dev, NULL);
Moore, Erice935d5d2006-03-14 09:18:18 -0700728}
729EXPORT_SYMBOL_GPL(device_reprobe);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731/**
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800732 * find_bus - locate bus by name.
733 * @name: name of bus.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734 *
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800735 * Call kset_find_obj() to iterate over list of buses to
736 * find a bus by name. Return bus if found.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700737 *
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800738 * Note that kset_find_obj increments bus' reference count.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739 */
Adrian Bunk7e4ef082006-06-26 22:26:56 +0200740#if 0
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800741struct bus_type *find_bus(char *name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742{
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800743 struct kobject *k = kset_find_obj(bus_kset, name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744 return k ? to_bus(k) : NULL;
745}
Adrian Bunk7e4ef082006-06-26 22:26:56 +0200746#endif /* 0 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747
Greg Kroah-Hartman12478ba2013-08-08 15:22:57 -0700748static int bus_add_groups(struct bus_type *bus,
749 const struct attribute_group **groups)
750{
Greg Kroah-Hartman3e9b2ba2013-08-21 13:47:50 -0700751 return sysfs_create_groups(&bus->p->subsys.kobj, groups);
Greg Kroah-Hartman12478ba2013-08-08 15:22:57 -0700752}
753
754static void bus_remove_groups(struct bus_type *bus,
755 const struct attribute_group **groups)
756{
Greg Kroah-Hartman3e9b2ba2013-08-21 13:47:50 -0700757 sysfs_remove_groups(&bus->p->subsys.kobj, groups);
Greg Kroah-Hartman12478ba2013-08-08 15:22:57 -0700758}
759
James Bottomley34bb61f2005-09-06 16:56:51 -0700760static void klist_devices_get(struct klist_node *n)
761{
Greg Kroah-Hartmanae1b4172008-12-16 12:26:21 -0800762 struct device_private *dev_prv = to_device_private_bus(n);
763 struct device *dev = dev_prv->device;
James Bottomley34bb61f2005-09-06 16:56:51 -0700764
765 get_device(dev);
766}
767
768static void klist_devices_put(struct klist_node *n)
769{
Greg Kroah-Hartmanae1b4172008-12-16 12:26:21 -0800770 struct device_private *dev_prv = to_device_private_bus(n);
771 struct device *dev = dev_prv->device;
James Bottomley34bb61f2005-09-06 16:56:51 -0700772
773 put_device(dev);
774}
775
Kay Sievers7ac1cf42007-08-12 20:43:55 +0200776static ssize_t bus_uevent_store(struct bus_type *bus,
777 const char *buf, size_t count)
778{
Peter Rajnohadf44b472018-12-05 12:27:44 +0100779 int rc;
780
781 rc = kobject_synth_uevent(&bus->p->subsys.kobj, buf, count);
782 return rc ? rc : count;
Kay Sievers7ac1cf42007-08-12 20:43:55 +0200783}
Greg Kroah-Hartmana4723042018-10-29 16:31:26 +0100784/*
785 * "open code" the old BUS_ATTR() macro here. We want to use BUS_ATTR_WO()
786 * here, but can not use it as earlier in the file we have
787 * DEVICE_ATTR_WO(uevent), which would cause a clash with the with the store
788 * function name.
789 */
790static struct bus_attribute bus_attr_uevent = __ATTR(uevent, S_IWUSR, NULL,
791 bus_uevent_store);
Kay Sievers7ac1cf42007-08-12 20:43:55 +0200792
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793/**
Michal Hockobe871b72013-03-12 17:21:19 +0100794 * bus_register - register a driver-core subsystem
Randy Dunlap78d79552012-01-21 11:02:28 -0800795 * @bus: bus to register
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796 *
Randy Dunlap78d79552012-01-21 11:02:28 -0800797 * Once we have that, we register the bus with the kobject
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800798 * infrastructure, then register the children subsystems it has:
Kay Sieversca22e562011-12-14 14:29:38 -0800799 * the devices and drivers that belong to the subsystem.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800 */
Michal Hockobe871b72013-03-12 17:21:19 +0100801int bus_register(struct bus_type *bus)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802{
803 int retval;
Kay Sievers6b6e39a2010-11-15 23:13:18 +0100804 struct subsys_private *priv;
Michal Hockobe871b72013-03-12 17:21:19 +0100805 struct lock_class_key *key = &bus->lock_key;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806
Kay Sievers6b6e39a2010-11-15 23:13:18 +0100807 priv = kzalloc(sizeof(struct subsys_private), GFP_KERNEL);
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700808 if (!priv)
809 return -ENOMEM;
Benjamin Herrenschmidt116af372006-10-25 13:44:59 +1000810
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700811 priv->bus = bus;
812 bus->p = priv;
813
814 BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier);
815
816 retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817 if (retval)
818 goto out;
819
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700820 priv->subsys.kobj.kset = bus_kset;
821 priv->subsys.kobj.ktype = &bus_ktype;
822 priv->drivers_autoprobe = 1;
Greg Kroah-Hartmand6b05b82007-09-12 15:06:57 -0700823
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700824 retval = kset_register(&priv->subsys);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825 if (retval)
826 goto out;
827
Kay Sievers7ac1cf42007-08-12 20:43:55 +0200828 retval = bus_create_file(bus, &bus_attr_uevent);
829 if (retval)
830 goto bus_uevent_fail;
831
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700832 priv->devices_kset = kset_create_and_add("devices", NULL,
833 &priv->subsys.kobj);
834 if (!priv->devices_kset) {
Greg Kroah-Hartman3d899592007-11-01 13:31:26 -0700835 retval = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836 goto bus_devices_fail;
Greg Kroah-Hartman3d899592007-11-01 13:31:26 -0700837 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700839 priv->drivers_kset = kset_create_and_add("drivers", NULL,
840 &priv->subsys.kobj);
841 if (!priv->drivers_kset) {
Greg Kroah-Hartman6dcec252007-11-01 13:31:26 -0700842 retval = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843 goto bus_drivers_fail;
Greg Kroah-Hartman6dcec252007-11-01 13:31:26 -0700844 }
mochel@digitalimplant.org465c7a32005-03-21 11:49:14 -0800845
Kay Sieversca22e562011-12-14 14:29:38 -0800846 INIT_LIST_HEAD(&priv->interfaces);
847 __mutex_init(&priv->mutex, "subsys mutex", key);
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700848 klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put);
849 klist_init(&priv->klist_drivers, NULL, NULL);
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100850
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100851 retval = add_probe_files(bus);
852 if (retval)
853 goto bus_probe_files_fail;
854
Greg Kroah-Hartman12478ba2013-08-08 15:22:57 -0700855 retval = bus_add_groups(bus, bus->bus_groups);
856 if (retval)
857 goto bus_groups_fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858
Greg Kroah-Hartman7dc72b22007-11-28 23:49:41 -0800859 pr_debug("bus: '%s': registered\n", bus->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700860 return 0;
861
Greg Kroah-Hartman12478ba2013-08-08 15:22:57 -0700862bus_groups_fail:
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100863 remove_probe_files(bus);
864bus_probe_files_fail:
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700865 kset_unregister(bus->p->drivers_kset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866bus_drivers_fail:
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700867 kset_unregister(bus->p->devices_kset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868bus_devices_fail:
Kay Sievers7ac1cf42007-08-12 20:43:55 +0200869 bus_remove_file(bus, &bus_attr_uevent);
870bus_uevent_fail:
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700871 kset_unregister(&bus->p->subsys);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872out:
Jike Song600c20f2010-07-15 17:43:54 +0800873 kfree(bus->p);
Dave Youngf48f3fe2009-02-14 21:23:22 +0800874 bus->p = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875 return retval;
876}
Michal Hockobe871b72013-03-12 17:21:19 +0100877EXPORT_SYMBOL_GPL(bus_register);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879/**
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800880 * bus_unregister - remove a bus from the system
881 * @bus: bus.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882 *
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800883 * Unregister the child subsystems and the bus itself.
884 * Finally, we call bus_put() to release the refcount
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 */
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800886void bus_unregister(struct bus_type *bus)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887{
Greg Kroah-Hartman7dc72b22007-11-28 23:49:41 -0800888 pr_debug("bus: '%s': unregistering\n", bus->name);
Kay Sieversca22e562011-12-14 14:29:38 -0800889 if (bus->dev_root)
890 device_unregister(bus->dev_root);
Greg Kroah-Hartman12478ba2013-08-08 15:22:57 -0700891 bus_remove_groups(bus, bus->bus_groups);
Kay Sieversb8c5cec2007-02-16 17:33:36 +0100892 remove_probe_files(bus);
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700893 kset_unregister(bus->p->drivers_kset);
894 kset_unregister(bus->p->devices_kset);
Kay Sievers7ac1cf42007-08-12 20:43:55 +0200895 bus_remove_file(bus, &bus_attr_uevent);
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700896 kset_unregister(&bus->p->subsys);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897}
Greg Kroah-Hartman4a3ad202008-01-24 22:50:12 -0800898EXPORT_SYMBOL_GPL(bus_unregister);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899
Benjamin Herrenschmidt116af372006-10-25 13:44:59 +1000900int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
901{
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700902 return blocking_notifier_chain_register(&bus->p->bus_notifier, nb);
Benjamin Herrenschmidt116af372006-10-25 13:44:59 +1000903}
904EXPORT_SYMBOL_GPL(bus_register_notifier);
905
906int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
907{
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700908 return blocking_notifier_chain_unregister(&bus->p->bus_notifier, nb);
Benjamin Herrenschmidt116af372006-10-25 13:44:59 +1000909}
910EXPORT_SYMBOL_GPL(bus_unregister_notifier);
911
Greg Kroah-Hartman0fed80f2007-11-01 19:41:16 -0700912struct kset *bus_get_kset(struct bus_type *bus)
913{
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700914 return &bus->p->subsys;
Greg Kroah-Hartman0fed80f2007-11-01 19:41:16 -0700915}
916EXPORT_SYMBOL_GPL(bus_get_kset);
917
Greg Kroah-Hartmanb2490722007-11-01 19:41:16 -0700918struct klist *bus_get_device_klist(struct bus_type *bus)
919{
Greg Kroah-Hartmanc6f7e722007-11-01 19:41:16 -0700920 return &bus->p->klist_devices;
Greg Kroah-Hartmanb2490722007-11-01 19:41:16 -0700921}
922EXPORT_SYMBOL_GPL(bus_get_device_klist);
923
Greg Kroah-Hartman99178b02008-08-26 11:00:57 -0500924/*
Robert P. J. Daydca25eb2010-11-21 08:15:01 -0500925 * Yes, this forcibly breaks the klist abstraction temporarily. It
Greg Kroah-Hartman99178b02008-08-26 11:00:57 -0500926 * just wants to sort the klist, not change reference counts and
927 * take/drop locks rapidly in the process. It does all this while
928 * holding the lock for the list, so objects can't otherwise be
929 * added/removed while we're swizzling.
930 */
931static void device_insertion_sort_klist(struct device *a, struct list_head *list,
932 int (*compare)(const struct device *a,
933 const struct device *b))
934{
Greg Kroah-Hartman99178b02008-08-26 11:00:57 -0500935 struct klist_node *n;
Greg Kroah-Hartmanae1b4172008-12-16 12:26:21 -0800936 struct device_private *dev_prv;
Greg Kroah-Hartman99178b02008-08-26 11:00:57 -0500937 struct device *b;
938
Geliang Tang4c627852016-01-05 23:03:37 +0800939 list_for_each_entry(n, list, n_node) {
Greg Kroah-Hartmanae1b4172008-12-16 12:26:21 -0800940 dev_prv = to_device_private_bus(n);
941 b = dev_prv->device;
Greg Kroah-Hartman99178b02008-08-26 11:00:57 -0500942 if (compare(a, b) <= 0) {
Greg Kroah-Hartmanae1b4172008-12-16 12:26:21 -0800943 list_move_tail(&a->p->knode_bus.n_node,
944 &b->p->knode_bus.n_node);
Greg Kroah-Hartman99178b02008-08-26 11:00:57 -0500945 return;
946 }
947 }
Greg Kroah-Hartmanae1b4172008-12-16 12:26:21 -0800948 list_move_tail(&a->p->knode_bus.n_node, list);
Greg Kroah-Hartman99178b02008-08-26 11:00:57 -0500949}
950
951void bus_sort_breadthfirst(struct bus_type *bus,
952 int (*compare)(const struct device *a,
953 const struct device *b))
954{
955 LIST_HEAD(sorted_devices);
Geliang Tang4c627852016-01-05 23:03:37 +0800956 struct klist_node *n, *tmp;
Greg Kroah-Hartmanae1b4172008-12-16 12:26:21 -0800957 struct device_private *dev_prv;
Greg Kroah-Hartman99178b02008-08-26 11:00:57 -0500958 struct device *dev;
959 struct klist *device_klist;
960
961 device_klist = bus_get_device_klist(bus);
962
963 spin_lock(&device_klist->k_lock);
Geliang Tang4c627852016-01-05 23:03:37 +0800964 list_for_each_entry_safe(n, tmp, &device_klist->k_list, n_node) {
Greg Kroah-Hartmanae1b4172008-12-16 12:26:21 -0800965 dev_prv = to_device_private_bus(n);
966 dev = dev_prv->device;
Greg Kroah-Hartman99178b02008-08-26 11:00:57 -0500967 device_insertion_sort_klist(dev, &sorted_devices, compare);
968 }
969 list_splice(&sorted_devices, &device_klist->k_list);
970 spin_unlock(&device_klist->k_lock);
971}
972EXPORT_SYMBOL_GPL(bus_sort_breadthfirst);
973
Kay Sieversca22e562011-12-14 14:29:38 -0800974/**
975 * subsys_dev_iter_init - initialize subsys device iterator
976 * @iter: subsys iterator to initialize
977 * @subsys: the subsys we wanna iterate over
978 * @start: the device to start iterating from, if any
979 * @type: device_type of the devices to iterate over, NULL for all
980 *
981 * Initialize subsys iterator @iter such that it iterates over devices
982 * of @subsys. If @start is set, the list iteration will start there,
983 * otherwise if it is NULL, the iteration starts at the beginning of
984 * the list.
985 */
Greg Kroah-Hartman7cd9c9b2012-04-19 19:17:30 -0700986void subsys_dev_iter_init(struct subsys_dev_iter *iter, struct bus_type *subsys,
987 struct device *start, const struct device_type *type)
Kay Sieversca22e562011-12-14 14:29:38 -0800988{
989 struct klist_node *start_knode = NULL;
990
991 if (start)
992 start_knode = &start->p->knode_bus;
Greg Kroah-Hartman7cd9c9b2012-04-19 19:17:30 -0700993 klist_iter_init_node(&subsys->p->klist_devices, &iter->ki, start_knode);
994 iter->type = type;
Kay Sieversca22e562011-12-14 14:29:38 -0800995}
996EXPORT_SYMBOL_GPL(subsys_dev_iter_init);
997
998/**
999 * subsys_dev_iter_next - iterate to the next device
1000 * @iter: subsys iterator to proceed
1001 *
1002 * Proceed @iter to the next device and return it. Returns NULL if
1003 * iteration is complete.
1004 *
1005 * The returned device is referenced and won't be released till
1006 * iterator is proceed to the next device or exited. The caller is
1007 * free to do whatever it wants to do with the device including
1008 * calling back into subsys code.
1009 */
1010struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter)
1011{
1012 struct klist_node *knode;
1013 struct device *dev;
1014
1015 for (;;) {
1016 knode = klist_next(&iter->ki);
1017 if (!knode)
1018 return NULL;
Geliang Tang371fd7a2016-01-05 23:03:38 +08001019 dev = to_device_private_bus(knode)->device;
Kay Sieversca22e562011-12-14 14:29:38 -08001020 if (!iter->type || iter->type == dev->type)
1021 return dev;
1022 }
1023}
1024EXPORT_SYMBOL_GPL(subsys_dev_iter_next);
1025
1026/**
1027 * subsys_dev_iter_exit - finish iteration
1028 * @iter: subsys iterator to finish
1029 *
1030 * Finish an iteration. Always call this function after iteration is
1031 * complete whether the iteration ran till the end or not.
1032 */
1033void subsys_dev_iter_exit(struct subsys_dev_iter *iter)
1034{
1035 klist_iter_exit(&iter->ki);
1036}
1037EXPORT_SYMBOL_GPL(subsys_dev_iter_exit);
1038
1039int subsys_interface_register(struct subsys_interface *sif)
1040{
1041 struct bus_type *subsys;
1042 struct subsys_dev_iter iter;
1043 struct device *dev;
1044
1045 if (!sif || !sif->subsys)
1046 return -ENODEV;
1047
1048 subsys = bus_get(sif->subsys);
1049 if (!subsys)
1050 return -EINVAL;
1051
1052 mutex_lock(&subsys->p->mutex);
1053 list_add_tail(&sif->node, &subsys->p->interfaces);
1054 if (sif->add_dev) {
1055 subsys_dev_iter_init(&iter, subsys, NULL, NULL);
1056 while ((dev = subsys_dev_iter_next(&iter)))
1057 sif->add_dev(dev, sif);
1058 subsys_dev_iter_exit(&iter);
1059 }
1060 mutex_unlock(&subsys->p->mutex);
1061
1062 return 0;
1063}
1064EXPORT_SYMBOL_GPL(subsys_interface_register);
1065
1066void subsys_interface_unregister(struct subsys_interface *sif)
1067{
Jonghwan Choi2b315942012-01-14 11:06:03 +09001068 struct bus_type *subsys;
Kay Sieversca22e562011-12-14 14:29:38 -08001069 struct subsys_dev_iter iter;
1070 struct device *dev;
1071
Jonghwan Choi2b315942012-01-14 11:06:03 +09001072 if (!sif || !sif->subsys)
Kay Sieversca22e562011-12-14 14:29:38 -08001073 return;
1074
Jonghwan Choi2b315942012-01-14 11:06:03 +09001075 subsys = sif->subsys;
1076
Kay Sieversca22e562011-12-14 14:29:38 -08001077 mutex_lock(&subsys->p->mutex);
1078 list_del_init(&sif->node);
1079 if (sif->remove_dev) {
1080 subsys_dev_iter_init(&iter, subsys, NULL, NULL);
1081 while ((dev = subsys_dev_iter_next(&iter)))
1082 sif->remove_dev(dev, sif);
1083 subsys_dev_iter_exit(&iter);
1084 }
1085 mutex_unlock(&subsys->p->mutex);
1086
1087 bus_put(subsys);
1088}
1089EXPORT_SYMBOL_GPL(subsys_interface_unregister);
1090
1091static void system_root_device_release(struct device *dev)
1092{
1093 kfree(dev);
1094}
Tejun Heod73ce002013-03-12 11:30:05 -07001095
1096static int subsys_register(struct bus_type *subsys,
1097 const struct attribute_group **groups,
1098 struct kobject *parent_of_root)
1099{
1100 struct device *dev;
1101 int err;
1102
1103 err = bus_register(subsys);
1104 if (err < 0)
1105 return err;
1106
1107 dev = kzalloc(sizeof(struct device), GFP_KERNEL);
1108 if (!dev) {
1109 err = -ENOMEM;
1110 goto err_dev;
1111 }
1112
1113 err = dev_set_name(dev, "%s", subsys->name);
1114 if (err < 0)
1115 goto err_name;
1116
1117 dev->kobj.parent = parent_of_root;
1118 dev->groups = groups;
1119 dev->release = system_root_device_release;
1120
1121 err = device_register(dev);
1122 if (err < 0)
1123 goto err_dev_reg;
1124
1125 subsys->dev_root = dev;
1126 return 0;
1127
1128err_dev_reg:
1129 put_device(dev);
1130 dev = NULL;
1131err_name:
1132 kfree(dev);
1133err_dev:
1134 bus_unregister(subsys);
1135 return err;
1136}
1137
Kay Sieversca22e562011-12-14 14:29:38 -08001138/**
1139 * subsys_system_register - register a subsystem at /sys/devices/system/
Randy Dunlap78d79552012-01-21 11:02:28 -08001140 * @subsys: system subsystem
1141 * @groups: default attributes for the root device
Kay Sieversca22e562011-12-14 14:29:38 -08001142 *
1143 * All 'system' subsystems have a /sys/devices/system/<name> root device
1144 * with the name of the subsystem. The root device can carry subsystem-
1145 * wide attributes. All registered devices are below this single root
1146 * device and are named after the subsystem with a simple enumeration
Masanari Iidae2278672014-02-18 22:54:36 +09001147 * number appended. The registered devices are not explicitly named;
Kay Sieversca22e562011-12-14 14:29:38 -08001148 * only 'id' in the device needs to be set.
1149 *
1150 * Do not use this interface for anything new, it exists for compatibility
1151 * with bad ideas only. New subsystems should use plain subsystems; and
1152 * add the subsystem-wide attributes should be added to the subsystem
1153 * directory itself and not some create fake root-device placed in
1154 * /sys/devices/system/<name>.
1155 */
1156int subsys_system_register(struct bus_type *subsys,
1157 const struct attribute_group **groups)
1158{
Tejun Heod73ce002013-03-12 11:30:05 -07001159 return subsys_register(subsys, groups, &system_kset->kobj);
Kay Sieversca22e562011-12-14 14:29:38 -08001160}
1161EXPORT_SYMBOL_GPL(subsys_system_register);
1162
Tejun Heod73ce002013-03-12 11:30:05 -07001163/**
1164 * subsys_virtual_register - register a subsystem at /sys/devices/virtual/
1165 * @subsys: virtual subsystem
1166 * @groups: default attributes for the root device
1167 *
1168 * All 'virtual' subsystems have a /sys/devices/system/<name> root device
1169 * with the name of the subystem. The root device can carry subsystem-wide
1170 * attributes. All registered devices are below this single root device.
1171 * There's no restriction on device naming. This is for kernel software
1172 * constructs which need sysfs interface.
1173 */
1174int subsys_virtual_register(struct bus_type *subsys,
1175 const struct attribute_group **groups)
1176{
1177 struct kobject *virtual_dir;
1178
1179 virtual_dir = virtual_device_parent(NULL);
1180 if (!virtual_dir)
1181 return -ENOMEM;
1182
1183 return subsys_register(subsys, groups, virtual_dir);
1184}
Greg Kroah-Hartman1c04fc32013-05-10 09:14:04 -07001185EXPORT_SYMBOL_GPL(subsys_virtual_register);
Tejun Heod73ce002013-03-12 11:30:05 -07001186
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187int __init buses_init(void)
1188{
Greg Kroah-Hartman59a54832007-10-29 23:22:26 -05001189 bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);
1190 if (!bus_kset)
1191 return -ENOMEM;
Kay Sieversca22e562011-12-14 14:29:38 -08001192
1193 system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj);
1194 if (!system_kset)
1195 return -ENOMEM;
1196
Greg Kroah-Hartman59a54832007-10-29 23:22:26 -05001197 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001198}