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
21 struct device_driver;
22 struct 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 *
52 * @online: Called to put the device back online (after offlining it).
53 * @offline: Called to put the device offline for hot-removal. May fail.
54 *
55 * @suspend: Called when a device on this bus wants to go to sleep mode.
56 * @resume: Called to bring a device on this bus out of sleep mode.
57 * @num_vf: Called to find out how many virtual functions a device on this
58 * bus supports.
59 * @dma_configure: Called to setup DMA configuration on a device on
60 * this bus.
61 * @dma_cleanup: Called to cleanup DMA configuration on a device on
62 * this bus.
63 * @pm: Power management operations of this bus, callback the specific
64 * device driver's pm-ops.
65 * @need_parent_lock: When probing or removing a device on this bus, the
66 * device core should lock the device's parent.
67 *
68 * A bus is a channel between the processor and one or more devices. For the
69 * purposes of the device model, all devices are connected via a bus, even if
70 * it is an internal, virtual, "platform" bus. Buses can plug into each other.
71 * A USB controller is usually a PCI device, for example. The device model
72 * represents the actual connections between buses and the devices they control.
73 * A bus is represented by the bus_type structure. It contains the name, the
74 * default attributes, the bus' methods, PM operations, and the driver core's
75 * private data.
76 */
77 struct bus_type {
78 const char *name;
79 const char *dev_name;
80 const struct attribute_group **bus_groups;
81 const struct attribute_group **dev_groups;
82 const struct attribute_group **drv_groups;
83
84 int (*match)(struct device *dev, struct device_driver *drv);
85 int (*uevent)(const struct device *dev, struct kobj_uevent_env *env);
86 int (*probe)(struct device *dev);
87 void (*sync_state)(struct device *dev);
88 void (*remove)(struct device *dev);
89 void (*shutdown)(struct device *dev);
90
91 int (*online)(struct device *dev);
92 int (*offline)(struct device *dev);
93
94 int (*suspend)(struct device *dev, pm_message_t state);
95 int (*resume)(struct device *dev);
96
97 int (*num_vf)(struct device *dev);
98
99 int (*dma_configure)(struct device *dev);
100 void (*dma_cleanup)(struct device *dev);
101
102 const struct dev_pm_ops *pm;
103
104 bool need_parent_lock;
105 };
106
107 int __must_check bus_register(const struct bus_type *bus);
108
109 void bus_unregister(const struct bus_type *bus);
110
111 int __must_check bus_rescan_devices(const struct bus_type *bus);
112
113 struct bus_attribute {
114 struct attribute attr;
115 ssize_t (*show)(const struct bus_type *bus, char *buf);
116 ssize_t (*store)(const struct bus_type *bus, const char *buf, size_t count);
117 };
118
119 #define BUS_ATTR_RW(_name) \
120 struct bus_attribute bus_attr_##_name = __ATTR_RW(_name)
121 #define BUS_ATTR_RO(_name) \
122 struct bus_attribute bus_attr_##_name = __ATTR_RO(_name)
123 #define BUS_ATTR_WO(_name) \
124 struct bus_attribute bus_attr_##_name = __ATTR_WO(_name)
125
126 int __must_check bus_create_file(const struct bus_type *bus, struct bus_attribute *attr);
127 void bus_remove_file(const struct bus_type *bus, struct bus_attribute *attr);
128
129 /* Generic device matching functions that all busses can use to match with */
130 int device_match_name(struct device *dev, const void *name);
131 int device_match_of_node(struct device *dev, const void *np);
132 int device_match_fwnode(struct device *dev, const void *fwnode);
133 int device_match_devt(struct device *dev, const void *pdevt);
134 int device_match_acpi_dev(struct device *dev, const void *adev);
135 int device_match_acpi_handle(struct device *dev, const void *handle);
136 int device_match_any(struct device *dev, const void *unused);
137
138 /* iterator helpers for buses */
139 int bus_for_each_dev(const struct bus_type *bus, struct device *start, void *data,
140 int (*fn)(struct device *dev, void *data));
141 struct device *bus_find_device(const struct bus_type *bus, struct device *start,
142 const void *data,
143 int (*match)(struct device *dev, const void *data));
144 /**
145 * bus_find_device_by_name - device iterator for locating a particular device
146 * of a specific name.
147 * @bus: bus type
148 * @start: Device to begin with
149 * @name: name of the device to match
150 */
bus_find_device_by_name(const struct bus_type * bus,struct device * start,const char * name)151 static inline struct device *bus_find_device_by_name(const struct bus_type *bus,
152 struct device *start,
153 const char *name)
154 {
155 return bus_find_device(bus, start, name, device_match_name);
156 }
157
158 /**
159 * bus_find_device_by_of_node : device iterator for locating a particular device
160 * matching the of_node.
161 * @bus: bus type
162 * @np: of_node of the device to match.
163 */
164 static inline struct device *
bus_find_device_by_of_node(const struct bus_type * bus,const struct device_node * np)165 bus_find_device_by_of_node(const struct bus_type *bus, const struct device_node *np)
166 {
167 return bus_find_device(bus, NULL, np, device_match_of_node);
168 }
169
170 /**
171 * bus_find_device_by_fwnode : device iterator for locating a particular device
172 * matching the fwnode.
173 * @bus: bus type
174 * @fwnode: fwnode of the device to match.
175 */
176 static inline struct device *
bus_find_device_by_fwnode(const struct bus_type * bus,const struct fwnode_handle * fwnode)177 bus_find_device_by_fwnode(const struct bus_type *bus, const struct fwnode_handle *fwnode)
178 {
179 return bus_find_device(bus, NULL, fwnode, device_match_fwnode);
180 }
181
182 /**
183 * bus_find_device_by_devt : device iterator for locating a particular device
184 * matching the device type.
185 * @bus: bus type
186 * @devt: device type of the device to match.
187 */
bus_find_device_by_devt(const struct bus_type * bus,dev_t devt)188 static inline struct device *bus_find_device_by_devt(const struct bus_type *bus,
189 dev_t devt)
190 {
191 return bus_find_device(bus, NULL, &devt, device_match_devt);
192 }
193
194 /**
195 * bus_find_next_device - Find the next device after a given device in a
196 * given bus.
197 * @bus: bus type
198 * @cur: device to begin the search with.
199 */
200 static inline struct device *
bus_find_next_device(const struct bus_type * bus,struct device * cur)201 bus_find_next_device(const struct bus_type *bus,struct device *cur)
202 {
203 return bus_find_device(bus, cur, NULL, device_match_any);
204 }
205
206 #ifdef CONFIG_ACPI
207 struct acpi_device;
208
209 /**
210 * bus_find_device_by_acpi_dev : device iterator for locating a particular device
211 * matching the ACPI COMPANION device.
212 * @bus: bus type
213 * @adev: ACPI COMPANION device to match.
214 */
215 static inline struct device *
bus_find_device_by_acpi_dev(const struct bus_type * bus,const struct acpi_device * adev)216 bus_find_device_by_acpi_dev(const struct bus_type *bus, const struct acpi_device *adev)
217 {
218 return bus_find_device(bus, NULL, adev, device_match_acpi_dev);
219 }
220 #else
221 static inline struct device *
bus_find_device_by_acpi_dev(const struct bus_type * bus,const void * adev)222 bus_find_device_by_acpi_dev(const struct bus_type *bus, const void *adev)
223 {
224 return NULL;
225 }
226 #endif
227
228 int bus_for_each_drv(const struct bus_type *bus, struct device_driver *start,
229 void *data, int (*fn)(struct device_driver *, void *));
230 void bus_sort_breadthfirst(const struct bus_type *bus,
231 int (*compare)(const struct device *a,
232 const struct device *b));
233 /*
234 * Bus notifiers: Get notified of addition/removal of devices
235 * and binding/unbinding of drivers to devices.
236 * In the long run, it should be a replacement for the platform
237 * notify hooks.
238 */
239 struct notifier_block;
240
241 int bus_register_notifier(const struct bus_type *bus, struct notifier_block *nb);
242 int bus_unregister_notifier(const struct bus_type *bus, struct notifier_block *nb);
243
244 /**
245 * enum bus_notifier_event - Bus Notifier events that have happened
246 * @BUS_NOTIFY_ADD_DEVICE: device is added to this bus
247 * @BUS_NOTIFY_DEL_DEVICE: device is about to be removed from this bus
248 * @BUS_NOTIFY_REMOVED_DEVICE: device is successfully removed from this bus
249 * @BUS_NOTIFY_BIND_DRIVER: a driver is about to be bound to this device on this bus
250 * @BUS_NOTIFY_BOUND_DRIVER: a driver is successfully bound to this device on this bus
251 * @BUS_NOTIFY_UNBIND_DRIVER: a driver is about to be unbound from this device on this bus
252 * @BUS_NOTIFY_UNBOUND_DRIVER: a driver is successfully unbound from this device on this bus
253 * @BUS_NOTIFY_DRIVER_NOT_BOUND: a driver failed to be bound to this device on this bus
254 *
255 * These are the value passed to a bus notifier when a specific event happens.
256 *
257 * Note that bus notifiers are likely to be called with the device lock already
258 * held by the driver core, so be careful in any notifier callback as to what
259 * you do with the device structure.
260 *
261 * All bus notifiers are called with the target struct device * as an argument.
262 */
263 enum bus_notifier_event {
264 BUS_NOTIFY_ADD_DEVICE,
265 BUS_NOTIFY_DEL_DEVICE,
266 BUS_NOTIFY_REMOVED_DEVICE,
267 BUS_NOTIFY_BIND_DRIVER,
268 BUS_NOTIFY_BOUND_DRIVER,
269 BUS_NOTIFY_UNBIND_DRIVER,
270 BUS_NOTIFY_UNBOUND_DRIVER,
271 BUS_NOTIFY_DRIVER_NOT_BOUND,
272 };
273
274 struct kset *bus_get_kset(const struct bus_type *bus);
275 struct device *bus_get_dev_root(const struct bus_type *bus);
276
277 #endif
278