1// SPDX-License-Identifier: GPL-2.0
2/*
3 * bus.h - the bus-specific portions of the driver model
4 *
5 * Copyright (c) 2001-2003 Patrick Mochel <mochel@osdl.org>
6 * Copyright (c) 2004-2009 Greg Kroah-Hartman <gregkh@suse.de>
7 * Copyright (c) 2008-2009 Novell Inc.
8 * Copyright (c) 2012-2019 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
9 * Copyright (c) 2012-2019 Linux Foundation
10 *
11 * See Documentation/driver-api/driver-model/ for more information.
12 */
13
14#ifndef _DEVICE_BUS_H_
15#define _DEVICE_BUS_H_
16
17#include <linux/kobject.h>
18#include <linux/klist.h>
19#include <linux/pm.h>
20
21struct device_driver;
22struct fwnode_handle;
23
24/**
25 * struct bus_type - The bus type of the device
26 *
27 * @name: The name of the bus.
28 * @dev_name: Used for subsystems to enumerate devices like ("foo%u", dev->id).
29 * @bus_groups: Default attributes of the bus.
30 * @dev_groups: Default attributes of the devices on the bus.
31 * @drv_groups: Default attributes of the device drivers on the bus.
32 * @match: Called, perhaps multiple times, whenever a new device or driver
33 * is added for this bus. It should return a positive value if the
34 * given device can be handled by the given driver and zero
35 * otherwise. It may also return error code if determining that
36 * the driver supports the device is not possible. In case of
37 * -EPROBE_DEFER it will queue the device for deferred probing.
38 * @uevent: Called when a device is added, removed, or a few other things
39 * that generate uevents to add the environment variables.
40 * @probe: Called when a new device or driver add to this bus, and callback
41 * the specific driver's probe to initial the matched device.
42 * @sync_state: Called to sync device state to software state after all the
43 * state tracking consumers linked to this device (present at
44 * the time of late_initcall) have successfully bound to a
45 * driver. If the device has no consumers, this function will
46 * be called at late_initcall_sync level. If the device has
47 * consumers that are never bound to a driver, this function
48 * will never get called until they do.
49 * @remove: Called when a device removed from this bus.
50 * @shutdown: Called at shut-down time to quiesce the device.
51 * @irq_get_affinity: Get IRQ affinity mask for the device on this bus.
52 *
53 * @online: Called to put the device back online (after offlining it).
54 * @offline: Called to put the device offline for hot-removal. May fail.
55 *
56 * @suspend: Called when a device on this bus wants to go to sleep mode.
57 * @resume: Called to bring a device on this bus out of sleep mode.
58 * @num_vf: Called to find out how many virtual functions a device on this
59 * bus supports.
60 * @dma_configure: Called to setup DMA configuration on a device on
61 * this bus.
62 * @dma_cleanup: Called to cleanup DMA configuration on a device on
63 * this bus.
64 * @pm: Power management operations of this bus, callback the specific
65 * device driver's pm-ops.
66 * @need_parent_lock: When probing or removing a device on this bus, the
67 * device core should lock the device's parent.
68 *
69 * A bus is a channel between the processor and one or more devices. For the
70 * purposes of the device model, all devices are connected via a bus, even if
71 * it is an internal, virtual, "platform" bus. Buses can plug into each other.
72 * A USB controller is usually a PCI device, for example. The device model
73 * represents the actual connections between buses and the devices they control.
74 * A bus is represented by the bus_type structure. It contains the name, the
75 * default attributes, the bus' methods, PM operations, and the driver core's
76 * private data.
77 */
78struct bus_type {
79 const char *name;
80 const char *dev_name;
81 const struct attribute_group **bus_groups;
82 const struct attribute_group **dev_groups;
83 const struct attribute_group **drv_groups;
84
85 int (*match)(struct device *dev, const struct device_driver *drv);
86 int (*uevent)(const struct device *dev, struct kobj_uevent_env *env);
87 int (*probe)(struct device *dev);
88 void (*sync_state)(struct device *dev);
89 void (*remove)(struct device *dev);
90 void (*shutdown)(struct device *dev);
91 const struct cpumask *(*irq_get_affinity)(struct device *dev,
92 unsigned int irq_vec);
93
94 int (*online)(struct device *dev);
95 int (*offline)(struct device *dev);
96
97 int (*suspend)(struct device *dev, pm_message_t state);
98 int (*resume)(struct device *dev);
99
100 int (*num_vf)(struct device *dev);
101
102 int (*dma_configure)(struct device *dev);
103 void (*dma_cleanup)(struct device *dev);
104
105 const struct dev_pm_ops *pm;
106
107 bool need_parent_lock;
108};
109
110int __must_check bus_register(const struct bus_type *bus);
111
112void bus_unregister(const struct bus_type *bus);
113
114int __must_check bus_rescan_devices(const struct bus_type *bus);
115
116struct bus_attribute {
117 struct attribute attr;
118 ssize_t (*show)(const struct bus_type *bus, char *buf);
119 ssize_t (*store)(const struct bus_type *bus, const char *buf, size_t count);
120};
121
122#define BUS_ATTR_RW(_name) \
123 struct bus_attribute bus_attr_##_name = __ATTR_RW(_name)
124#define BUS_ATTR_RO(_name) \
125 struct bus_attribute bus_attr_##_name = __ATTR_RO(_name)
126#define BUS_ATTR_WO(_name) \
127 struct bus_attribute bus_attr_##_name = __ATTR_WO(_name)
128
129int __must_check bus_create_file(const struct bus_type *bus, struct bus_attribute *attr);
130void bus_remove_file(const struct bus_type *bus, struct bus_attribute *attr);
131
132/* Matching function type for drivers/base APIs to find a specific device */
133typedef int (*device_match_t)(struct device *dev, const void *data);
134
135/* Generic device matching functions that all busses can use to match with */
136int device_match_name(struct device *dev, const void *name);
137int device_match_type(struct device *dev, const void *type);
138int device_match_of_node(struct device *dev, const void *np);
139int device_match_fwnode(struct device *dev, const void *fwnode);
140int device_match_devt(struct device *dev, const void *pdevt);
141int device_match_acpi_dev(struct device *dev, const void *adev);
142int device_match_acpi_handle(struct device *dev, const void *handle);
143int device_match_any(struct device *dev, const void *unused);
144
145/* Device iterating function type for various driver core for_each APIs */
146typedef int (*device_iter_t)(struct device *dev, void *data);
147
148/* iterator helpers for buses */
149int bus_for_each_dev(const struct bus_type *bus, struct device *start,
150 void *data, device_iter_t fn);
151struct device *bus_find_device(const struct bus_type *bus, struct device *start,
152 const void *data, device_match_t match);
153/**
154 * bus_find_device_by_name - device iterator for locating a particular device
155 * of a specific name.
156 * @bus: bus type
157 * @start: Device to begin with
158 * @name: name of the device to match
159 */
160static inline struct device *bus_find_device_by_name(const struct bus_type *bus,
161 struct device *start,
162 const char *name)
163{
164 return bus_find_device(bus, start, data: name, match: device_match_name);
165}
166
167/**
168 * bus_find_device_by_of_node : device iterator for locating a particular device
169 * matching the of_node.
170 * @bus: bus type
171 * @np: of_node of the device to match.
172 */
173static inline struct device *
174bus_find_device_by_of_node(const struct bus_type *bus, const struct device_node *np)
175{
176 return bus_find_device(bus, NULL, data: np, match: device_match_of_node);
177}
178
179/**
180 * bus_find_device_by_fwnode : device iterator for locating a particular device
181 * matching the fwnode.
182 * @bus: bus type
183 * @fwnode: fwnode of the device to match.
184 */
185static inline struct device *
186bus_find_device_by_fwnode(const struct bus_type *bus, const struct fwnode_handle *fwnode)
187{
188 return bus_find_device(bus, NULL, data: fwnode, match: device_match_fwnode);
189}
190
191/**
192 * bus_find_device_by_devt : device iterator for locating a particular device
193 * matching the device type.
194 * @bus: bus type
195 * @devt: device type of the device to match.
196 */
197static inline struct device *bus_find_device_by_devt(const struct bus_type *bus,
198 dev_t devt)
199{
200 return bus_find_device(bus, NULL, data: &devt, match: device_match_devt);
201}
202
203/**
204 * bus_find_next_device - Find the next device after a given device in a
205 * given bus.
206 * @bus: bus type
207 * @cur: device to begin the search with.
208 */
209static inline struct device *
210bus_find_next_device(const struct bus_type *bus,struct device *cur)
211{
212 return bus_find_device(bus, start: cur, NULL, match: device_match_any);
213}
214
215#ifdef CONFIG_ACPI
216struct acpi_device;
217
218/**
219 * bus_find_device_by_acpi_dev : device iterator for locating a particular device
220 * matching the ACPI COMPANION device.
221 * @bus: bus type
222 * @adev: ACPI COMPANION device to match.
223 */
224static inline struct device *
225bus_find_device_by_acpi_dev(const struct bus_type *bus, const struct acpi_device *adev)
226{
227 return bus_find_device(bus, NULL, data: adev, match: device_match_acpi_dev);
228}
229#else
230static inline struct device *
231bus_find_device_by_acpi_dev(const struct bus_type *bus, const void *adev)
232{
233 return NULL;
234}
235#endif
236
237int bus_for_each_drv(const struct bus_type *bus, struct device_driver *start,
238 void *data, int (*fn)(struct device_driver *, void *));
239void bus_sort_breadthfirst(const struct bus_type *bus,
240 int (*compare)(const struct device *a,
241 const struct device *b));
242/*
243 * Bus notifiers: Get notified of addition/removal of devices
244 * and binding/unbinding of drivers to devices.
245 * In the long run, it should be a replacement for the platform
246 * notify hooks.
247 */
248struct notifier_block;
249
250int bus_register_notifier(const struct bus_type *bus, struct notifier_block *nb);
251int bus_unregister_notifier(const struct bus_type *bus, struct notifier_block *nb);
252
253/**
254 * enum bus_notifier_event - Bus Notifier events that have happened
255 * @BUS_NOTIFY_ADD_DEVICE: device is added to this bus
256 * @BUS_NOTIFY_DEL_DEVICE: device is about to be removed from this bus
257 * @BUS_NOTIFY_REMOVED_DEVICE: device is successfully removed from this bus
258 * @BUS_NOTIFY_BIND_DRIVER: a driver is about to be bound to this device on this bus
259 * @BUS_NOTIFY_BOUND_DRIVER: a driver is successfully bound to this device on this bus
260 * @BUS_NOTIFY_UNBIND_DRIVER: a driver is about to be unbound from this device on this bus
261 * @BUS_NOTIFY_UNBOUND_DRIVER: a driver is successfully unbound from this device on this bus
262 * @BUS_NOTIFY_DRIVER_NOT_BOUND: a driver failed to be bound to this device on this bus
263 *
264 * These are the value passed to a bus notifier when a specific event happens.
265 *
266 * Note that bus notifiers are likely to be called with the device lock already
267 * held by the driver core, so be careful in any notifier callback as to what
268 * you do with the device structure.
269 *
270 * All bus notifiers are called with the target struct device * as an argument.
271 */
272enum bus_notifier_event {
273 BUS_NOTIFY_ADD_DEVICE,
274 BUS_NOTIFY_DEL_DEVICE,
275 BUS_NOTIFY_REMOVED_DEVICE,
276 BUS_NOTIFY_BIND_DRIVER,
277 BUS_NOTIFY_BOUND_DRIVER,
278 BUS_NOTIFY_UNBIND_DRIVER,
279 BUS_NOTIFY_UNBOUND_DRIVER,
280 BUS_NOTIFY_DRIVER_NOT_BOUND,
281};
282
283struct kset *bus_get_kset(const struct bus_type *bus);
284struct device *bus_get_dev_root(const struct bus_type *bus);
285
286#endif
287