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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 | static inline struct device *bus_find_device_by_name(struct bus_type *bus, | |
173 | struct device *start, | |
174 | const char *name) | |
175 | { | |
176 | 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 | bus_find_device_by_of_node(struct bus_type *bus, const struct device_node *np) | |
187 | { | |
188 | 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 | static inline struct device *bus_find_device_by_devt(struct bus_type *bus, | |
210 | dev_t devt) | |
211 | { | |
212 | 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 | bus_find_next_device(struct bus_type *bus,struct device *cur) | |
223 | { | |
224 | 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 | bus_find_device_by_acpi_dev(struct bus_type *bus, const struct acpi_device *adev) | |
238 | { | |
239 | 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 |