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 | return bus_find_device(bus, start, data: name, match: 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, data: np, match: 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 | return bus_find_device(bus, NULL, data: fwnode, match: 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, data: &devt, match: 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 | return bus_find_device(bus, start: cur, NULL, match: 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, data: adev, match: 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 |
283 | |