Line data Source code
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 : * @dev_root: Default device to use as the parent.
30 : * @bus_groups: Default attributes of the bus.
31 : * @dev_groups: Default attributes of the devices on the bus.
32 : * @drv_groups: Default attributes of the device drivers on the bus.
33 : * @match: Called, perhaps multiple times, whenever a new device or driver
34 : * is added for this bus. It should return a positive value if the
35 : * given device can be handled by the given driver and zero
36 : * otherwise. It may also return error code if determining that
37 : * the driver supports the device is not possible. In case of
38 : * -EPROBE_DEFER it will queue the device for deferred probing.
39 : * @uevent: Called when a device is added, removed, or a few other things
40 : * that generate uevents to add the environment variables.
41 : * @probe: Called when a new device or driver add to this bus, and callback
42 : * the specific driver's probe to initial the matched device.
43 : * @sync_state: Called to sync device state to software state after all the
44 : * state tracking consumers linked to this device (present at
45 : * the time of late_initcall) have successfully bound to a
46 : * driver. If the device has no consumers, this function will
47 : * be called at late_initcall_sync level. If the device has
48 : * consumers that are never bound to a driver, this function
49 : * will never get called until they do.
50 : * @remove: Called when a device removed from this bus.
51 : * @shutdown: Called at shut-down time to quiesce the device.
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 : * @iommu_ops: IOMMU specific operations for this bus, used to attach IOMMU
67 : * driver implementations to a bus and allow the driver to do
68 : * bus-specific setup
69 : * @lock_key: Lock class key for use by the lock validator
70 : * @need_parent_lock: When probing or removing a device on this bus, the
71 : * device core should lock the device's parent.
72 : *
73 : * A bus is a channel between the processor and one or more devices. For the
74 : * purposes of the device model, all devices are connected via a bus, even if
75 : * it is an internal, virtual, "platform" bus. Buses can plug into each other.
76 : * A USB controller is usually a PCI device, for example. The device model
77 : * represents the actual connections between buses and the devices they control.
78 : * A bus is represented by the bus_type structure. It contains the name, the
79 : * default attributes, the bus' methods, PM operations, and the driver core's
80 : * private data.
81 : */
82 : struct bus_type {
83 : const char *name;
84 : const char *dev_name;
85 : struct device *dev_root;
86 : const struct attribute_group **bus_groups;
87 : const struct attribute_group **dev_groups;
88 : const struct attribute_group **drv_groups;
89 :
90 : int (*match)(struct device *dev, struct device_driver *drv);
91 : int (*uevent)(const struct device *dev, struct kobj_uevent_env *env);
92 : int (*probe)(struct device *dev);
93 : void (*sync_state)(struct device *dev);
94 : void (*remove)(struct device *dev);
95 : void (*shutdown)(struct device *dev);
96 :
97 : int (*online)(struct device *dev);
98 : int (*offline)(struct device *dev);
99 :
100 : int (*suspend)(struct device *dev, pm_message_t state);
101 : int (*resume)(struct device *dev);
102 :
103 : int (*num_vf)(struct device *dev);
104 :
105 : int (*dma_configure)(struct device *dev);
106 : void (*dma_cleanup)(struct device *dev);
107 :
108 : const struct dev_pm_ops *pm;
109 :
110 : const struct iommu_ops *iommu_ops;
111 :
112 : bool need_parent_lock;
113 : };
114 :
115 : extern int __must_check bus_register(struct bus_type *bus);
116 :
117 : extern void bus_unregister(const struct bus_type *bus);
118 :
119 : extern int __must_check bus_rescan_devices(struct bus_type *bus);
120 :
121 : struct bus_attribute {
122 : struct attribute attr;
123 : ssize_t (*show)(struct bus_type *bus, char *buf);
124 : ssize_t (*store)(struct bus_type *bus, const char *buf, size_t count);
125 : };
126 :
127 : #define BUS_ATTR_RW(_name) \
128 : struct bus_attribute bus_attr_##_name = __ATTR_RW(_name)
129 : #define BUS_ATTR_RO(_name) \
130 : struct bus_attribute bus_attr_##_name = __ATTR_RO(_name)
131 : #define BUS_ATTR_WO(_name) \
132 : struct bus_attribute bus_attr_##_name = __ATTR_WO(_name)
133 :
134 : int __must_check bus_create_file(const struct bus_type *bus, struct bus_attribute *attr);
135 : void bus_remove_file(const struct bus_type *bus, struct bus_attribute *attr);
136 :
137 : /* Generic device matching functions that all busses can use to match with */
138 : int device_match_name(struct device *dev, const void *name);
139 : int device_match_of_node(struct device *dev, const void *np);
140 : int device_match_fwnode(struct device *dev, const void *fwnode);
141 : int device_match_devt(struct device *dev, const void *pdevt);
142 : int device_match_acpi_dev(struct device *dev, const void *adev);
143 : int device_match_acpi_handle(struct device *dev, const void *handle);
144 : int device_match_any(struct device *dev, const void *unused);
145 :
146 : /* iterator helpers for buses */
147 : int bus_for_each_dev(const struct bus_type *bus, struct device *start, void *data,
148 : int (*fn)(struct device *dev, void *data));
149 : struct device *bus_find_device(const struct bus_type *bus, struct device *start,
150 : const void *data,
151 : int (*match)(struct device *dev, const void *data));
152 : /**
153 : * bus_find_device_by_name - device iterator for locating a particular device
154 : * of a specific name.
155 : * @bus: bus type
156 : * @start: Device to begin with
157 : * @name: name of the device to match
158 : */
159 : static inline struct device *bus_find_device_by_name(const struct bus_type *bus,
160 : struct device *start,
161 : const char *name)
162 : {
163 0 : return bus_find_device(bus, start, name, device_match_name);
164 : }
165 :
166 : /**
167 : * bus_find_device_by_of_node : device iterator for locating a particular device
168 : * matching the of_node.
169 : * @bus: bus type
170 : * @np: of_node of the device to match.
171 : */
172 : static inline struct device *
173 : bus_find_device_by_of_node(const struct bus_type *bus, const struct device_node *np)
174 : {
175 : return bus_find_device(bus, NULL, np, device_match_of_node);
176 : }
177 :
178 : /**
179 : * bus_find_device_by_fwnode : device iterator for locating a particular device
180 : * matching the fwnode.
181 : * @bus: bus type
182 : * @fwnode: fwnode of the device to match.
183 : */
184 : static inline struct device *
185 : bus_find_device_by_fwnode(const struct bus_type *bus, const struct fwnode_handle *fwnode)
186 : {
187 0 : return bus_find_device(bus, NULL, fwnode, device_match_fwnode);
188 : }
189 :
190 : /**
191 : * bus_find_device_by_devt : device iterator for locating a particular device
192 : * matching the device type.
193 : * @bus: bus type
194 : * @devt: device type of the device to match.
195 : */
196 : static inline struct device *bus_find_device_by_devt(const struct bus_type *bus,
197 : dev_t devt)
198 : {
199 : return bus_find_device(bus, NULL, &devt, device_match_devt);
200 : }
201 :
202 : /**
203 : * bus_find_next_device - Find the next device after a given device in a
204 : * given bus.
205 : * @bus: bus type
206 : * @cur: device to begin the search with.
207 : */
208 : static inline struct device *
209 : bus_find_next_device(const struct bus_type *bus,struct device *cur)
210 : {
211 0 : return bus_find_device(bus, cur, NULL, device_match_any);
212 : }
213 :
214 : #ifdef CONFIG_ACPI
215 : struct acpi_device;
216 :
217 : /**
218 : * bus_find_device_by_acpi_dev : device iterator for locating a particular device
219 : * matching the ACPI COMPANION device.
220 : * @bus: bus type
221 : * @adev: ACPI COMPANION device to match.
222 : */
223 : static inline struct device *
224 : bus_find_device_by_acpi_dev(const struct bus_type *bus, const struct acpi_device *adev)
225 : {
226 : return bus_find_device(bus, NULL, adev, device_match_acpi_dev);
227 : }
228 : #else
229 : static inline struct device *
230 : bus_find_device_by_acpi_dev(const struct bus_type *bus, const void *adev)
231 : {
232 : return NULL;
233 : }
234 : #endif
235 :
236 : int bus_for_each_drv(const struct bus_type *bus, struct device_driver *start,
237 : void *data, int (*fn)(struct device_driver *, void *));
238 : void bus_sort_breadthfirst(struct bus_type *bus,
239 : int (*compare)(const struct device *a,
240 : const struct device *b));
241 : /*
242 : * Bus notifiers: Get notified of addition/removal of devices
243 : * and binding/unbinding of drivers to devices.
244 : * In the long run, it should be a replacement for the platform
245 : * notify hooks.
246 : */
247 : struct notifier_block;
248 :
249 : extern int bus_register_notifier(const struct bus_type *bus,
250 : struct notifier_block *nb);
251 : extern int bus_unregister_notifier(const struct bus_type *bus,
252 : struct notifier_block *nb);
253 :
254 : /**
255 : * enum bus_notifier_event - Bus Notifier events that have happened
256 : * @BUS_NOTIFY_ADD_DEVICE: device is added to this bus
257 : * @BUS_NOTIFY_DEL_DEVICE: device is about to be removed from this bus
258 : * @BUS_NOTIFY_REMOVED_DEVICE: device is successfully removed from this bus
259 : * @BUS_NOTIFY_BIND_DRIVER: a driver is about to be bound to this device on this bus
260 : * @BUS_NOTIFY_BOUND_DRIVER: a driver is successfully bound to this device on this bus
261 : * @BUS_NOTIFY_UNBIND_DRIVER: a driver is about to be unbound from this device on this bus
262 : * @BUS_NOTIFY_UNBOUND_DRIVER: a driver is successfully unbound from this device on this bus
263 : * @BUS_NOTIFY_DRIVER_NOT_BOUND: a driver failed to be bound to this device on this bus
264 : *
265 : * These are the value passed to a bus notifier when a specific event happens.
266 : *
267 : * Note that bus notifiers are likely to be called with the device lock already
268 : * held by the driver core, so be careful in any notifier callback as to what
269 : * you do with the device structure.
270 : *
271 : * All bus notifiers are called with the target struct device * as an argument.
272 : */
273 : enum bus_notifier_event {
274 : BUS_NOTIFY_ADD_DEVICE,
275 : BUS_NOTIFY_DEL_DEVICE,
276 : BUS_NOTIFY_REMOVED_DEVICE,
277 : BUS_NOTIFY_BIND_DRIVER,
278 : BUS_NOTIFY_BOUND_DRIVER,
279 : BUS_NOTIFY_UNBIND_DRIVER,
280 : BUS_NOTIFY_UNBOUND_DRIVER,
281 : BUS_NOTIFY_DRIVER_NOT_BOUND,
282 : };
283 :
284 : extern struct kset *bus_get_kset(const struct bus_type *bus);
285 : struct device *bus_get_dev_root(const struct bus_type *bus);
286 :
287 : #endif
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