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 : * @pm: Power management operations of this bus, callback the specific
63 : * device driver's pm-ops.
64 : * @iommu_ops: IOMMU specific operations for this bus, used to attach IOMMU
65 : * driver implementations to a bus and allow the driver to do
66 : * bus-specific setup
67 : * @p: The private data of the driver core, only the driver core can
68 : * touch this.
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)(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 :
107 : const struct dev_pm_ops *pm;
108 :
109 : const struct iommu_ops *iommu_ops;
110 :
111 : struct subsys_private *p;
112 : struct lock_class_key lock_key;
113 :
114 : bool need_parent_lock;
115 : };
116 :
117 : extern int __must_check bus_register(struct bus_type *bus);
118 :
119 : extern void bus_unregister(struct bus_type *bus);
120 :
121 : extern int __must_check bus_rescan_devices(struct bus_type *bus);
122 :
123 : struct bus_attribute {
124 : struct attribute attr;
125 : ssize_t (*show)(struct bus_type *bus, char *buf);
126 : ssize_t (*store)(struct bus_type *bus, const char *buf, size_t count);
127 : };
128 :
129 : #define BUS_ATTR_RW(_name) \
130 : struct bus_attribute bus_attr_##_name = __ATTR_RW(_name)
131 : #define BUS_ATTR_RO(_name) \
132 : struct bus_attribute bus_attr_##_name = __ATTR_RO(_name)
133 : #define BUS_ATTR_WO(_name) \
134 : struct bus_attribute bus_attr_##_name = __ATTR_WO(_name)
135 :
136 : extern int __must_check bus_create_file(struct bus_type *,
137 : struct bus_attribute *);
138 : extern void bus_remove_file(struct bus_type *, struct bus_attribute *);
139 :
140 : /* Generic device matching functions that all busses can use to match with */
141 : int device_match_name(struct device *dev, const void *name);
142 : int device_match_of_node(struct device *dev, const void *np);
143 : int device_match_fwnode(struct device *dev, const void *fwnode);
144 : int device_match_devt(struct device *dev, const void *pdevt);
145 : int device_match_acpi_dev(struct device *dev, const void *adev);
146 : int device_match_acpi_handle(struct device *dev, const void *handle);
147 : int device_match_any(struct device *dev, const void *unused);
148 :
149 : /* iterator helpers for buses */
150 : struct subsys_dev_iter {
151 : struct klist_iter ki;
152 : const struct device_type *type;
153 : };
154 : void subsys_dev_iter_init(struct subsys_dev_iter *iter,
155 : struct bus_type *subsys,
156 : struct device *start,
157 : const struct device_type *type);
158 : struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter);
159 : void subsys_dev_iter_exit(struct subsys_dev_iter *iter);
160 :
161 : int bus_for_each_dev(struct bus_type *bus, struct device *start, void *data,
162 : int (*fn)(struct device *dev, void *data));
163 : struct device *bus_find_device(struct bus_type *bus, struct device *start,
164 : const void *data,
165 : int (*match)(struct device *dev, const void *data));
166 : /**
167 : * bus_find_device_by_name - device iterator for locating a particular device
168 : * of a specific name.
169 : * @bus: bus type
170 : * @start: Device to begin with
171 : * @name: name of the device to match
172 : */
173 : static inline struct device *bus_find_device_by_name(struct bus_type *bus,
174 : struct device *start,
175 : const char *name)
176 : {
177 0 : return bus_find_device(bus, start, name, device_match_name);
178 : }
179 :
180 : /**
181 : * bus_find_device_by_of_node : device iterator for locating a particular device
182 : * matching the of_node.
183 : * @bus: bus type
184 : * @np: of_node of the device to match.
185 : */
186 : static inline struct device *
187 : bus_find_device_by_of_node(struct bus_type *bus, const struct device_node *np)
188 : {
189 : return bus_find_device(bus, NULL, np, device_match_of_node);
190 : }
191 :
192 : /**
193 : * bus_find_device_by_fwnode : device iterator for locating a particular device
194 : * matching the fwnode.
195 : * @bus: bus type
196 : * @fwnode: fwnode of the device to match.
197 : */
198 : static inline struct device *
199 : bus_find_device_by_fwnode(struct bus_type *bus, const struct fwnode_handle *fwnode)
200 : {
201 : return bus_find_device(bus, NULL, fwnode, device_match_fwnode);
202 : }
203 :
204 : /**
205 : * bus_find_device_by_devt : device iterator for locating a particular device
206 : * matching the device type.
207 : * @bus: bus type
208 : * @devt: device type of the device to match.
209 : */
210 : static inline struct device *bus_find_device_by_devt(struct bus_type *bus,
211 : dev_t devt)
212 : {
213 : return bus_find_device(bus, NULL, &devt, device_match_devt);
214 : }
215 :
216 : /**
217 : * bus_find_next_device - Find the next device after a given device in a
218 : * given bus.
219 : * @bus: bus type
220 : * @cur: device to begin the search with.
221 : */
222 : static inline struct device *
223 : bus_find_next_device(struct bus_type *bus,struct device *cur)
224 : {
225 0 : return bus_find_device(bus, cur, NULL, device_match_any);
226 : }
227 :
228 : #ifdef CONFIG_ACPI
229 : struct acpi_device;
230 :
231 : /**
232 : * bus_find_device_by_acpi_dev : device iterator for locating a particular device
233 : * matching the ACPI COMPANION device.
234 : * @bus: bus type
235 : * @adev: ACPI COMPANION device to match.
236 : */
237 : static inline struct device *
238 : bus_find_device_by_acpi_dev(struct bus_type *bus, const struct acpi_device *adev)
239 : {
240 : return bus_find_device(bus, NULL, adev, device_match_acpi_dev);
241 : }
242 : #else
243 : static inline struct device *
244 : bus_find_device_by_acpi_dev(struct bus_type *bus, const void *adev)
245 : {
246 : return NULL;
247 : }
248 : #endif
249 :
250 : struct device *subsys_find_device_by_id(struct bus_type *bus, unsigned int id,
251 : struct device *hint);
252 : int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
253 : void *data, int (*fn)(struct device_driver *, void *));
254 : void bus_sort_breadthfirst(struct bus_type *bus,
255 : int (*compare)(const struct device *a,
256 : const struct device *b));
257 : /*
258 : * Bus notifiers: Get notified of addition/removal of devices
259 : * and binding/unbinding of drivers to devices.
260 : * In the long run, it should be a replacement for the platform
261 : * notify hooks.
262 : */
263 : struct notifier_block;
264 :
265 : extern int bus_register_notifier(struct bus_type *bus,
266 : struct notifier_block *nb);
267 : extern int bus_unregister_notifier(struct bus_type *bus,
268 : struct notifier_block *nb);
269 :
270 : /* All 4 notifers below get called with the target struct device *
271 : * as an argument. Note that those functions are likely to be called
272 : * with the device lock held in the core, so be careful.
273 : */
274 : #define BUS_NOTIFY_ADD_DEVICE 0x00000001 /* device added */
275 : #define BUS_NOTIFY_DEL_DEVICE 0x00000002 /* device to be removed */
276 : #define BUS_NOTIFY_REMOVED_DEVICE 0x00000003 /* device removed */
277 : #define BUS_NOTIFY_BIND_DRIVER 0x00000004 /* driver about to be
278 : bound */
279 : #define BUS_NOTIFY_BOUND_DRIVER 0x00000005 /* driver bound to device */
280 : #define BUS_NOTIFY_UNBIND_DRIVER 0x00000006 /* driver about to be
281 : unbound */
282 : #define BUS_NOTIFY_UNBOUND_DRIVER 0x00000007 /* driver is unbound
283 : from the device */
284 : #define BUS_NOTIFY_DRIVER_NOT_BOUND 0x00000008 /* driver fails to be bound */
285 :
286 : extern struct kset *bus_get_kset(struct bus_type *bus);
287 : extern struct klist *bus_get_device_klist(struct bus_type *bus);
288 :
289 : #endif
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