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 : * @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 : * @iommu_ops: IOMMU specific operations for this bus, used to attach IOMMU
66 : * driver implementations to a bus and allow the driver to do
67 : * bus-specific setup
68 : * @need_parent_lock: When probing or removing a device on this bus, the
69 : * device core should lock the device's parent.
70 : *
71 : * A bus is a channel between the processor and one or more devices. For the
72 : * purposes of the device model, all devices are connected via a bus, even if
73 : * it is an internal, virtual, "platform" bus. Buses can plug into each other.
74 : * A USB controller is usually a PCI device, for example. The device model
75 : * represents the actual connections between buses and the devices they control.
76 : * A bus is represented by the bus_type structure. It contains the name, the
77 : * default attributes, the bus' methods, PM operations, and the driver core's
78 : * private data.
79 : */
80 : struct bus_type {
81 : const char *name;
82 : const char *dev_name;
83 : const struct attribute_group **bus_groups;
84 : const struct attribute_group **dev_groups;
85 : const struct attribute_group **drv_groups;
86 :
87 : int (*match)(struct device *dev, struct device_driver *drv);
88 : int (*uevent)(const struct device *dev, struct kobj_uevent_env *env);
89 : int (*probe)(struct device *dev);
90 : void (*sync_state)(struct device *dev);
91 : void (*remove)(struct device *dev);
92 : void (*shutdown)(struct device *dev);
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 : const struct iommu_ops *iommu_ops;
108 :
109 : bool need_parent_lock;
110 : };
111 :
112 : int __must_check bus_register(const struct bus_type *bus);
113 :
114 : void bus_unregister(const struct bus_type *bus);
115 :
116 : int __must_check bus_rescan_devices(const struct bus_type *bus);
117 :
118 : struct bus_attribute {
119 : struct attribute attr;
120 : ssize_t (*show)(const struct bus_type *bus, char *buf);
121 : ssize_t (*store)(const struct bus_type *bus, const char *buf, size_t count);
122 : };
123 :
124 : #define BUS_ATTR_RW(_name) \
125 : struct bus_attribute bus_attr_##_name = __ATTR_RW(_name)
126 : #define BUS_ATTR_RO(_name) \
127 : struct bus_attribute bus_attr_##_name = __ATTR_RO(_name)
128 : #define BUS_ATTR_WO(_name) \
129 : struct bus_attribute bus_attr_##_name = __ATTR_WO(_name)
130 :
131 : int __must_check bus_create_file(const struct bus_type *bus, struct bus_attribute *attr);
132 : void bus_remove_file(const struct bus_type *bus, struct bus_attribute *attr);
133 :
134 : /* Generic device matching functions that all busses can use to match with */
135 : int device_match_name(struct device *dev, const void *name);
136 : int device_match_of_node(struct device *dev, const void *np);
137 : int device_match_fwnode(struct device *dev, const void *fwnode);
138 : int device_match_devt(struct device *dev, const void *pdevt);
139 : int device_match_acpi_dev(struct device *dev, const void *adev);
140 : int device_match_acpi_handle(struct device *dev, const void *handle);
141 : int device_match_any(struct device *dev, const void *unused);
142 :
143 : /* iterator helpers for buses */
144 : int bus_for_each_dev(const struct bus_type *bus, struct device *start, void *data,
145 : int (*fn)(struct device *dev, void *data));
146 : struct device *bus_find_device(const struct bus_type *bus, struct device *start,
147 : const void *data,
148 : int (*match)(struct device *dev, const void *data));
149 : /**
150 : * bus_find_device_by_name - device iterator for locating a particular device
151 : * of a specific name.
152 : * @bus: bus type
153 : * @start: Device to begin with
154 : * @name: name of the device to match
155 : */
156 : static inline struct device *bus_find_device_by_name(const struct bus_type *bus,
157 : struct device *start,
158 : const char *name)
159 : {
160 0 : return bus_find_device(bus, start, name, device_match_name);
161 : }
162 :
163 : /**
164 : * bus_find_device_by_of_node : device iterator for locating a particular device
165 : * matching the of_node.
166 : * @bus: bus type
167 : * @np: of_node of the device to match.
168 : */
169 : static inline struct device *
170 : bus_find_device_by_of_node(const struct bus_type *bus, const struct device_node *np)
171 : {
172 : return bus_find_device(bus, NULL, np, device_match_of_node);
173 : }
174 :
175 : /**
176 : * bus_find_device_by_fwnode : device iterator for locating a particular device
177 : * matching the fwnode.
178 : * @bus: bus type
179 : * @fwnode: fwnode of the device to match.
180 : */
181 : static inline struct device *
182 : bus_find_device_by_fwnode(const struct bus_type *bus, const struct fwnode_handle *fwnode)
183 : {
184 0 : return bus_find_device(bus, NULL, fwnode, device_match_fwnode);
185 : }
186 :
187 : /**
188 : * bus_find_device_by_devt : device iterator for locating a particular device
189 : * matching the device type.
190 : * @bus: bus type
191 : * @devt: device type of the device to match.
192 : */
193 : static inline struct device *bus_find_device_by_devt(const struct bus_type *bus,
194 : dev_t devt)
195 : {
196 : return bus_find_device(bus, NULL, &devt, device_match_devt);
197 : }
198 :
199 : /**
200 : * bus_find_next_device - Find the next device after a given device in a
201 : * given bus.
202 : * @bus: bus type
203 : * @cur: device to begin the search with.
204 : */
205 : static inline struct device *
206 : bus_find_next_device(const struct bus_type *bus,struct device *cur)
207 : {
208 0 : return bus_find_device(bus, cur, NULL, device_match_any);
209 : }
210 :
211 : #ifdef CONFIG_ACPI
212 : struct acpi_device;
213 :
214 : /**
215 : * bus_find_device_by_acpi_dev : device iterator for locating a particular device
216 : * matching the ACPI COMPANION device.
217 : * @bus: bus type
218 : * @adev: ACPI COMPANION device to match.
219 : */
220 : static inline struct device *
221 : bus_find_device_by_acpi_dev(const struct bus_type *bus, const struct acpi_device *adev)
222 : {
223 : return bus_find_device(bus, NULL, adev, device_match_acpi_dev);
224 : }
225 : #else
226 : static inline struct device *
227 : bus_find_device_by_acpi_dev(const struct bus_type *bus, const void *adev)
228 : {
229 : return NULL;
230 : }
231 : #endif
232 :
233 : int bus_for_each_drv(const struct bus_type *bus, struct device_driver *start,
234 : void *data, int (*fn)(struct device_driver *, void *));
235 : void bus_sort_breadthfirst(struct bus_type *bus,
236 : int (*compare)(const struct device *a,
237 : const struct device *b));
238 : /*
239 : * Bus notifiers: Get notified of addition/removal of devices
240 : * and binding/unbinding of drivers to devices.
241 : * In the long run, it should be a replacement for the platform
242 : * notify hooks.
243 : */
244 : struct notifier_block;
245 :
246 : int bus_register_notifier(const struct bus_type *bus, struct notifier_block *nb);
247 : int bus_unregister_notifier(const struct bus_type *bus, struct notifier_block *nb);
248 :
249 : /**
250 : * enum bus_notifier_event - Bus Notifier events that have happened
251 : * @BUS_NOTIFY_ADD_DEVICE: device is added to this bus
252 : * @BUS_NOTIFY_DEL_DEVICE: device is about to be removed from this bus
253 : * @BUS_NOTIFY_REMOVED_DEVICE: device is successfully removed from this bus
254 : * @BUS_NOTIFY_BIND_DRIVER: a driver is about to be bound to this device on this bus
255 : * @BUS_NOTIFY_BOUND_DRIVER: a driver is successfully bound to this device on this bus
256 : * @BUS_NOTIFY_UNBIND_DRIVER: a driver is about to be unbound from this device on this bus
257 : * @BUS_NOTIFY_UNBOUND_DRIVER: a driver is successfully unbound from this device on this bus
258 : * @BUS_NOTIFY_DRIVER_NOT_BOUND: a driver failed to be bound to this device on this bus
259 : *
260 : * These are the value passed to a bus notifier when a specific event happens.
261 : *
262 : * Note that bus notifiers are likely to be called with the device lock already
263 : * held by the driver core, so be careful in any notifier callback as to what
264 : * you do with the device structure.
265 : *
266 : * All bus notifiers are called with the target struct device * as an argument.
267 : */
268 : enum bus_notifier_event {
269 : BUS_NOTIFY_ADD_DEVICE,
270 : BUS_NOTIFY_DEL_DEVICE,
271 : BUS_NOTIFY_REMOVED_DEVICE,
272 : BUS_NOTIFY_BIND_DRIVER,
273 : BUS_NOTIFY_BOUND_DRIVER,
274 : BUS_NOTIFY_UNBIND_DRIVER,
275 : BUS_NOTIFY_UNBOUND_DRIVER,
276 : BUS_NOTIFY_DRIVER_NOT_BOUND,
277 : };
278 :
279 : struct kset *bus_get_kset(const struct bus_type *bus);
280 : struct device *bus_get_dev_root(const struct bus_type *bus);
281 :
282 : #endif
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