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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 : : int (*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_any(struct device *dev, const void *unused);
147 : :
148 : : /* iterator helpers for buses */
149 : : struct subsys_dev_iter {
150 : : struct klist_iter ki;
151 : : const struct device_type *type;
152 : : };
153 : : void subsys_dev_iter_init(struct subsys_dev_iter *iter,
154 : : struct bus_type *subsys,
155 : : struct device *start,
156 : : const struct device_type *type);
157 : : struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter);
158 : : void subsys_dev_iter_exit(struct subsys_dev_iter *iter);
159 : :
160 : : int bus_for_each_dev(struct bus_type *bus, struct device *start, void *data,
161 : : int (*fn)(struct device *dev, void *data));
162 : : struct device *bus_find_device(struct bus_type *bus, struct device *start,
163 : : const void *data,
164 : : int (*match)(struct device *dev, const void *data));
165 : : /**
166 : : * bus_find_device_by_name - device iterator for locating a particular device
167 : : * of a specific name.
168 : : * @bus: bus type
169 : : * @start: Device to begin with
170 : : * @name: name of the device to match
171 : : */
172 : 0 : static inline struct device *bus_find_device_by_name(struct bus_type *bus,
173 : : struct device *start,
174 : : const char *name)
175 : : {
176 : 0 : return bus_find_device(bus, start, name, device_match_name);
177 : : }
178 : :
179 : : /**
180 : : * bus_find_device_by_of_node : device iterator for locating a particular device
181 : : * matching the of_node.
182 : : * @bus: bus type
183 : : * @np: of_node of the device to match.
184 : : */
185 : : static inline struct device *
186 : 0 : bus_find_device_by_of_node(struct bus_type *bus, const struct device_node *np)
187 : : {
188 : 0 : return bus_find_device(bus, NULL, np, device_match_of_node);
189 : : }
190 : :
191 : : /**
192 : : * bus_find_device_by_fwnode : device iterator for locating a particular device
193 : : * matching the fwnode.
194 : : * @bus: bus type
195 : : * @fwnode: fwnode of the device to match.
196 : : */
197 : : static inline struct device *
198 : : bus_find_device_by_fwnode(struct bus_type *bus, const struct fwnode_handle *fwnode)
199 : : {
200 : : return bus_find_device(bus, NULL, fwnode, device_match_fwnode);
201 : : }
202 : :
203 : : /**
204 : : * bus_find_device_by_devt : device iterator for locating a particular device
205 : : * matching the device type.
206 : : * @bus: bus type
207 : : * @devt: device type of the device to match.
208 : : */
209 : 0 : static inline struct device *bus_find_device_by_devt(struct bus_type *bus,
210 : : dev_t devt)
211 : : {
212 : 0 : return bus_find_device(bus, NULL, &devt, device_match_devt);
213 : : }
214 : :
215 : : /**
216 : : * bus_find_next_device - Find the next device after a given device in a
217 : : * given bus.
218 : : * @bus: bus type
219 : : * @cur: device to begin the search with.
220 : : */
221 : : static inline struct device *
222 : 0 : bus_find_next_device(struct bus_type *bus,struct device *cur)
223 : : {
224 : 0 : return bus_find_device(bus, cur, NULL, device_match_any);
225 : : }
226 : :
227 : : #ifdef CONFIG_ACPI
228 : : struct acpi_device;
229 : :
230 : : /**
231 : : * bus_find_device_by_acpi_dev : device iterator for locating a particular device
232 : : * matching the ACPI COMPANION device.
233 : : * @bus: bus type
234 : : * @adev: ACPI COMPANION device to match.
235 : : */
236 : : static inline struct device *
237 : 0 : bus_find_device_by_acpi_dev(struct bus_type *bus, const struct acpi_device *adev)
238 : : {
239 : 0 : return bus_find_device(bus, NULL, adev, device_match_acpi_dev);
240 : : }
241 : : #else
242 : : static inline struct device *
243 : : bus_find_device_by_acpi_dev(struct bus_type *bus, const void *adev)
244 : : {
245 : : return NULL;
246 : : }
247 : : #endif
248 : :
249 : : struct device *subsys_find_device_by_id(struct bus_type *bus, unsigned int id,
250 : : struct device *hint);
251 : : int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
252 : : void *data, int (*fn)(struct device_driver *, void *));
253 : : void bus_sort_breadthfirst(struct bus_type *bus,
254 : : int (*compare)(const struct device *a,
255 : : const struct device *b));
256 : : /*
257 : : * Bus notifiers: Get notified of addition/removal of devices
258 : : * and binding/unbinding of drivers to devices.
259 : : * In the long run, it should be a replacement for the platform
260 : : * notify hooks.
261 : : */
262 : : struct notifier_block;
263 : :
264 : : extern int bus_register_notifier(struct bus_type *bus,
265 : : struct notifier_block *nb);
266 : : extern int bus_unregister_notifier(struct bus_type *bus,
267 : : struct notifier_block *nb);
268 : :
269 : : /* All 4 notifers below get called with the target struct device *
270 : : * as an argument. Note that those functions are likely to be called
271 : : * with the device lock held in the core, so be careful.
272 : : */
273 : : #define BUS_NOTIFY_ADD_DEVICE 0x00000001 /* device added */
274 : : #define BUS_NOTIFY_DEL_DEVICE 0x00000002 /* device to be removed */
275 : : #define BUS_NOTIFY_REMOVED_DEVICE 0x00000003 /* device removed */
276 : : #define BUS_NOTIFY_BIND_DRIVER 0x00000004 /* driver about to be
277 : : bound */
278 : : #define BUS_NOTIFY_BOUND_DRIVER 0x00000005 /* driver bound to device */
279 : : #define BUS_NOTIFY_UNBIND_DRIVER 0x00000006 /* driver about to be
280 : : unbound */
281 : : #define BUS_NOTIFY_UNBOUND_DRIVER 0x00000007 /* driver is unbound
282 : : from the device */
283 : : #define BUS_NOTIFY_DRIVER_NOT_BOUND 0x00000008 /* driver fails to be bound */
284 : :
285 : : extern struct kset *bus_get_kset(struct bus_type *bus);
286 : : extern struct klist *bus_get_device_klist(struct bus_type *bus);
287 : :
288 : : #endif
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