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, const 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 /* Matching function type for drivers/base APIs to find a specific device */
130 typedef int (*device_match_t)(struct device *dev, const void *data);
131
132 /* Generic device matching functions that all busses can use to match with */
133 int device_match_name(struct device *dev, const void *name);
134 int device_match_of_node(struct device *dev, const void *np);
135 int device_match_fwnode(struct device *dev, const void *fwnode);
136 int device_match_devt(struct device *dev, const void *pdevt);
137 int device_match_acpi_dev(struct device *dev, const void *adev);
138 int device_match_acpi_handle(struct device *dev, const void *handle);
139 int device_match_any(struct device *dev, const void *unused);
140
141 /* iterator helpers for buses */
142 int bus_for_each_dev(const struct bus_type *bus, struct device *start, void *data,
143 int (*fn)(struct device *dev, void *data));
144 struct device *bus_find_device(const struct bus_type *bus, struct device *start,
145 const void *data, device_match_t match);
146 /**
147 * bus_find_device_by_name - device iterator for locating a particular device
148 * of a specific name.
149 * @bus: bus type
150 * @start: Device to begin with
151 * @name: name of the device to match
152 */
bus_find_device_by_name(const struct bus_type * bus,struct device * start,const char * name)153 static inline struct device *bus_find_device_by_name(const struct bus_type *bus,
154 struct device *start,
155 const char *name)
156 {
157 return bus_find_device(bus, start, name, device_match_name);
158 }
159
160 /**
161 * bus_find_device_by_of_node : device iterator for locating a particular device
162 * matching the of_node.
163 * @bus: bus type
164 * @np: of_node of the device to match.
165 */
166 static inline struct device *
bus_find_device_by_of_node(const struct bus_type * bus,const struct device_node * np)167 bus_find_device_by_of_node(const struct bus_type *bus, const struct device_node *np)
168 {
169 return bus_find_device(bus, NULL, np, device_match_of_node);
170 }
171
172 /**
173 * bus_find_device_by_fwnode : device iterator for locating a particular device
174 * matching the fwnode.
175 * @bus: bus type
176 * @fwnode: fwnode of the device to match.
177 */
178 static inline struct device *
bus_find_device_by_fwnode(const struct bus_type * bus,const struct fwnode_handle * fwnode)179 bus_find_device_by_fwnode(const struct bus_type *bus, const struct fwnode_handle *fwnode)
180 {
181 return bus_find_device(bus, NULL, fwnode, device_match_fwnode);
182 }
183
184 /**
185 * bus_find_device_by_devt : device iterator for locating a particular device
186 * matching the device type.
187 * @bus: bus type
188 * @devt: device type of the device to match.
189 */
bus_find_device_by_devt(const struct bus_type * bus,dev_t devt)190 static inline struct device *bus_find_device_by_devt(const struct bus_type *bus,
191 dev_t devt)
192 {
193 return bus_find_device(bus, NULL, &devt, device_match_devt);
194 }
195
196 /**
197 * bus_find_next_device - Find the next device after a given device in a
198 * given bus.
199 * @bus: bus type
200 * @cur: device to begin the search with.
201 */
202 static inline struct device *
bus_find_next_device(const struct bus_type * bus,struct device * cur)203 bus_find_next_device(const struct bus_type *bus,struct device *cur)
204 {
205 return bus_find_device(bus, cur, NULL, device_match_any);
206 }
207
208 #ifdef CONFIG_ACPI
209 struct acpi_device;
210
211 /**
212 * bus_find_device_by_acpi_dev : device iterator for locating a particular device
213 * matching the ACPI COMPANION device.
214 * @bus: bus type
215 * @adev: ACPI COMPANION device to match.
216 */
217 static inline struct device *
bus_find_device_by_acpi_dev(const struct bus_type * bus,const struct acpi_device * adev)218 bus_find_device_by_acpi_dev(const struct bus_type *bus, const struct acpi_device *adev)
219 {
220 return bus_find_device(bus, NULL, adev, device_match_acpi_dev);
221 }
222 #else
223 static inline struct device *
bus_find_device_by_acpi_dev(const struct bus_type * bus,const void * adev)224 bus_find_device_by_acpi_dev(const struct bus_type *bus, const void *adev)
225 {
226 return NULL;
227 }
228 #endif
229
230 int bus_for_each_drv(const struct bus_type *bus, struct device_driver *start,
231 void *data, int (*fn)(struct device_driver *, void *));
232 void bus_sort_breadthfirst(const struct bus_type *bus,
233 int (*compare)(const struct device *a,
234 const struct device *b));
235 /*
236 * Bus notifiers: Get notified of addition/removal of devices
237 * and binding/unbinding of drivers to devices.
238 * In the long run, it should be a replacement for the platform
239 * notify hooks.
240 */
241 struct notifier_block;
242
243 int bus_register_notifier(const struct bus_type *bus, struct notifier_block *nb);
244 int bus_unregister_notifier(const struct bus_type *bus, struct notifier_block *nb);
245
246 /**
247 * enum bus_notifier_event - Bus Notifier events that have happened
248 * @BUS_NOTIFY_ADD_DEVICE: device is added to this bus
249 * @BUS_NOTIFY_DEL_DEVICE: device is about to be removed from this bus
250 * @BUS_NOTIFY_REMOVED_DEVICE: device is successfully removed from this bus
251 * @BUS_NOTIFY_BIND_DRIVER: a driver is about to be bound to this device on this bus
252 * @BUS_NOTIFY_BOUND_DRIVER: a driver is successfully bound to this device on this bus
253 * @BUS_NOTIFY_UNBIND_DRIVER: a driver is about to be unbound from this device on this bus
254 * @BUS_NOTIFY_UNBOUND_DRIVER: a driver is successfully unbound from this device on this bus
255 * @BUS_NOTIFY_DRIVER_NOT_BOUND: a driver failed to be bound to this device on this bus
256 *
257 * These are the value passed to a bus notifier when a specific event happens.
258 *
259 * Note that bus notifiers are likely to be called with the device lock already
260 * held by the driver core, so be careful in any notifier callback as to what
261 * you do with the device structure.
262 *
263 * All bus notifiers are called with the target struct device * as an argument.
264 */
265 enum bus_notifier_event {
266 BUS_NOTIFY_ADD_DEVICE,
267 BUS_NOTIFY_DEL_DEVICE,
268 BUS_NOTIFY_REMOVED_DEVICE,
269 BUS_NOTIFY_BIND_DRIVER,
270 BUS_NOTIFY_BOUND_DRIVER,
271 BUS_NOTIFY_UNBIND_DRIVER,
272 BUS_NOTIFY_UNBOUND_DRIVER,
273 BUS_NOTIFY_DRIVER_NOT_BOUND,
274 };
275
276 struct kset *bus_get_kset(const struct bus_type *bus);
277 struct device *bus_get_dev_root(const struct bus_type *bus);
278
279 #endif
280