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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). | |
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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. | |
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61 | * @dma_cleanup: Called to cleanup DMA configuration on a device on |
62 | * this bus. | |
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63 | * @pm: Power management operations of this bus, callback the specific |
64 | * device driver's pm-ops. | |
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65 | * @need_parent_lock: When probing or removing a device on this bus, the |
66 | * device core should lock the device's parent. | |
67 | * | |
68 | * A bus is a channel between the processor and one or more devices. For the | |
69 | * purposes of the device model, all devices are connected via a bus, even if | |
70 | * it is an internal, virtual, "platform" bus. Buses can plug into each other. | |
71 | * A USB controller is usually a PCI device, for example. The device model | |
72 | * represents the actual connections between buses and the devices they control. | |
73 | * A bus is represented by the bus_type structure. It contains the name, the | |
74 | * default attributes, the bus' methods, PM operations, and the driver core's | |
75 | * private data. | |
76 | */ | |
77 | struct bus_type { | |
78 | const char *name; | |
79 | const char *dev_name; | |
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80 | const struct attribute_group **bus_groups; |
81 | const struct attribute_group **dev_groups; | |
82 | const struct attribute_group **drv_groups; | |
83 | ||
84 | int (*match)(struct device *dev, struct device_driver *drv); | |
2a81ada3 | 85 | int (*uevent)(const struct device *dev, struct kobj_uevent_env *env); |
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86 | int (*probe)(struct device *dev); |
87 | void (*sync_state)(struct device *dev); | |
fc7a6209 | 88 | void (*remove)(struct device *dev); |
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89 | void (*shutdown)(struct device *dev); |
90 | ||
91 | int (*online)(struct device *dev); | |
92 | int (*offline)(struct device *dev); | |
93 | ||
94 | int (*suspend)(struct device *dev, pm_message_t state); | |
95 | int (*resume)(struct device *dev); | |
96 | ||
97 | int (*num_vf)(struct device *dev); | |
98 | ||
99 | int (*dma_configure)(struct device *dev); | |
25f3bcfc | 100 | void (*dma_cleanup)(struct device *dev); |
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101 | |
102 | const struct dev_pm_ops *pm; | |
103 | ||
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104 | bool need_parent_lock; |
105 | }; | |
106 | ||
0d62b79f | 107 | int __must_check bus_register(const struct bus_type *bus); |
5aee2bf2 | 108 | |
0d62b79f | 109 | void bus_unregister(const struct bus_type *bus); |
5aee2bf2 | 110 | |
0d62b79f | 111 | int __must_check bus_rescan_devices(const struct bus_type *bus); |
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112 | |
113 | struct bus_attribute { | |
114 | struct attribute attr; | |
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115 | ssize_t (*show)(const struct bus_type *bus, char *buf); |
116 | ssize_t (*store)(const struct bus_type *bus, const char *buf, size_t count); | |
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117 | }; |
118 | ||
119 | #define BUS_ATTR_RW(_name) \ | |
120 | struct bus_attribute bus_attr_##_name = __ATTR_RW(_name) | |
121 | #define BUS_ATTR_RO(_name) \ | |
122 | struct bus_attribute bus_attr_##_name = __ATTR_RO(_name) | |
123 | #define BUS_ATTR_WO(_name) \ | |
124 | struct bus_attribute bus_attr_##_name = __ATTR_WO(_name) | |
125 | ||
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126 | int __must_check bus_create_file(const struct bus_type *bus, struct bus_attribute *attr); |
127 | void bus_remove_file(const struct bus_type *bus, struct bus_attribute *attr); | |
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128 | |
129 | /* Generic device matching functions that all busses can use to match with */ | |
130 | int device_match_name(struct device *dev, const void *name); | |
131 | int device_match_of_node(struct device *dev, const void *np); | |
132 | int device_match_fwnode(struct device *dev, const void *fwnode); | |
133 | int device_match_devt(struct device *dev, const void *pdevt); | |
134 | int device_match_acpi_dev(struct device *dev, const void *adev); | |
a164ff53 | 135 | int device_match_acpi_handle(struct device *dev, const void *handle); |
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136 | int device_match_any(struct device *dev, const void *unused); |
137 | ||
138 | /* iterator helpers for buses */ | |
e0766ea4 | 139 | int bus_for_each_dev(const struct bus_type *bus, struct device *start, void *data, |
5aee2bf2 | 140 | int (*fn)(struct device *dev, void *data)); |
e0766ea4 | 141 | struct device *bus_find_device(const struct bus_type *bus, struct device *start, |
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142 | const void *data, |
143 | int (*match)(struct device *dev, const void *data)); | |
144 | /** | |
145 | * bus_find_device_by_name - device iterator for locating a particular device | |
146 | * of a specific name. | |
147 | * @bus: bus type | |
148 | * @start: Device to begin with | |
149 | * @name: name of the device to match | |
150 | */ | |
e0766ea4 | 151 | static inline struct device *bus_find_device_by_name(const struct bus_type *bus, |
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152 | struct device *start, |
153 | const char *name) | |
154 | { | |
155 | return bus_find_device(bus, start, name, device_match_name); | |
156 | } | |
157 | ||
158 | /** | |
159 | * bus_find_device_by_of_node : device iterator for locating a particular device | |
160 | * matching the of_node. | |
161 | * @bus: bus type | |
162 | * @np: of_node of the device to match. | |
163 | */ | |
164 | static inline struct device * | |
e0766ea4 | 165 | bus_find_device_by_of_node(const struct bus_type *bus, const struct device_node *np) |
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166 | { |
167 | return bus_find_device(bus, NULL, np, device_match_of_node); | |
168 | } | |
169 | ||
170 | /** | |
171 | * bus_find_device_by_fwnode : device iterator for locating a particular device | |
172 | * matching the fwnode. | |
173 | * @bus: bus type | |
174 | * @fwnode: fwnode of the device to match. | |
175 | */ | |
176 | static inline struct device * | |
e0766ea4 | 177 | bus_find_device_by_fwnode(const struct bus_type *bus, const struct fwnode_handle *fwnode) |
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178 | { |
179 | return bus_find_device(bus, NULL, fwnode, device_match_fwnode); | |
180 | } | |
181 | ||
182 | /** | |
183 | * bus_find_device_by_devt : device iterator for locating a particular device | |
184 | * matching the device type. | |
185 | * @bus: bus type | |
186 | * @devt: device type of the device to match. | |
187 | */ | |
e0766ea4 | 188 | static inline struct device *bus_find_device_by_devt(const struct bus_type *bus, |
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189 | dev_t devt) |
190 | { | |
191 | return bus_find_device(bus, NULL, &devt, device_match_devt); | |
192 | } | |
193 | ||
194 | /** | |
195 | * bus_find_next_device - Find the next device after a given device in a | |
196 | * given bus. | |
197 | * @bus: bus type | |
198 | * @cur: device to begin the search with. | |
199 | */ | |
200 | static inline struct device * | |
e0766ea4 | 201 | bus_find_next_device(const struct bus_type *bus,struct device *cur) |
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202 | { |
203 | return bus_find_device(bus, cur, NULL, device_match_any); | |
204 | } | |
205 | ||
206 | #ifdef CONFIG_ACPI | |
207 | struct acpi_device; | |
208 | ||
209 | /** | |
210 | * bus_find_device_by_acpi_dev : device iterator for locating a particular device | |
211 | * matching the ACPI COMPANION device. | |
212 | * @bus: bus type | |
213 | * @adev: ACPI COMPANION device to match. | |
214 | */ | |
215 | static inline struct device * | |
e0766ea4 | 216 | bus_find_device_by_acpi_dev(const struct bus_type *bus, const struct acpi_device *adev) |
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217 | { |
218 | return bus_find_device(bus, NULL, adev, device_match_acpi_dev); | |
219 | } | |
220 | #else | |
221 | static inline struct device * | |
e0766ea4 | 222 | bus_find_device_by_acpi_dev(const struct bus_type *bus, const void *adev) |
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223 | { |
224 | return NULL; | |
225 | } | |
226 | #endif | |
227 | ||
e0766ea4 | 228 | int bus_for_each_drv(const struct bus_type *bus, struct device_driver *start, |
5aee2bf2 | 229 | void *data, int (*fn)(struct device_driver *, void *)); |
5ae81209 | 230 | void bus_sort_breadthfirst(const struct bus_type *bus, |
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231 | int (*compare)(const struct device *a, |
232 | const struct device *b)); | |
233 | /* | |
234 | * Bus notifiers: Get notified of addition/removal of devices | |
235 | * and binding/unbinding of drivers to devices. | |
236 | * In the long run, it should be a replacement for the platform | |
237 | * notify hooks. | |
238 | */ | |
239 | struct notifier_block; | |
240 | ||
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241 | int bus_register_notifier(const struct bus_type *bus, struct notifier_block *nb); |
242 | int bus_unregister_notifier(const struct bus_type *bus, struct notifier_block *nb); | |
5aee2bf2 | 243 | |
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244 | /** |
245 | * enum bus_notifier_event - Bus Notifier events that have happened | |
246 | * @BUS_NOTIFY_ADD_DEVICE: device is added to this bus | |
247 | * @BUS_NOTIFY_DEL_DEVICE: device is about to be removed from this bus | |
248 | * @BUS_NOTIFY_REMOVED_DEVICE: device is successfully removed from this bus | |
249 | * @BUS_NOTIFY_BIND_DRIVER: a driver is about to be bound to this device on this bus | |
250 | * @BUS_NOTIFY_BOUND_DRIVER: a driver is successfully bound to this device on this bus | |
251 | * @BUS_NOTIFY_UNBIND_DRIVER: a driver is about to be unbound from this device on this bus | |
252 | * @BUS_NOTIFY_UNBOUND_DRIVER: a driver is successfully unbound from this device on this bus | |
253 | * @BUS_NOTIFY_DRIVER_NOT_BOUND: a driver failed to be bound to this device on this bus | |
254 | * | |
255 | * These are the value passed to a bus notifier when a specific event happens. | |
256 | * | |
257 | * Note that bus notifiers are likely to be called with the device lock already | |
258 | * held by the driver core, so be careful in any notifier callback as to what | |
259 | * you do with the device structure. | |
260 | * | |
261 | * All bus notifiers are called with the target struct device * as an argument. | |
5aee2bf2 | 262 | */ |
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263 | enum bus_notifier_event { |
264 | BUS_NOTIFY_ADD_DEVICE, | |
265 | BUS_NOTIFY_DEL_DEVICE, | |
266 | BUS_NOTIFY_REMOVED_DEVICE, | |
267 | BUS_NOTIFY_BIND_DRIVER, | |
268 | BUS_NOTIFY_BOUND_DRIVER, | |
269 | BUS_NOTIFY_UNBIND_DRIVER, | |
270 | BUS_NOTIFY_UNBOUND_DRIVER, | |
271 | BUS_NOTIFY_DRIVER_NOT_BOUND, | |
272 | }; | |
5aee2bf2 | 273 | |
0d62b79f | 274 | struct kset *bus_get_kset(const struct bus_type *bus); |
8c99377e | 275 | struct device *bus_get_dev_root(const struct bus_type *bus); |
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276 | |
277 | #endif |