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 #include <linux/android_kabi.h>
21
22 struct device_driver;
23 struct fwnode_handle;
24
25 /**
26 * struct bus_type - The bus type of the device
27 *
28 * @name: The name of the bus.
29 * @dev_name: Used for subsystems to enumerate devices like ("foo%u", dev->id).
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 * @dma_cleanup: Called to cleanup DMA configuration on a device on
63 * this bus.
64 * @pm: Power management operations of this bus, callback the specific
65 * device driver's pm-ops.
66 * @need_parent_lock: When probing or removing a device on this bus, the
67 * device core should lock the device's parent.
68 *
69 * A bus is a channel between the processor and one or more devices. For the
70 * purposes of the device model, all devices are connected via a bus, even if
71 * it is an internal, virtual, "platform" bus. Buses can plug into each other.
72 * A USB controller is usually a PCI device, for example. The device model
73 * represents the actual connections between buses and the devices they control.
74 * A bus is represented by the bus_type structure. It contains the name, the
75 * default attributes, the bus' methods, PM operations, and the driver core's
76 * private data.
77 */
78 struct bus_type {
79 const char *name;
80 const char *dev_name;
81 const struct attribute_group **bus_groups;
82 const struct attribute_group **dev_groups;
83 const struct attribute_group **drv_groups;
84
85 int (*match)(struct device *dev, const struct device_driver *drv);
86 int (*uevent)(const struct device *dev, struct kobj_uevent_env *env);
87 int (*probe)(struct device *dev);
88 void (*sync_state)(struct device *dev);
89 void (*remove)(struct device *dev);
90 void (*shutdown)(struct device *dev);
91
92 int (*online)(struct device *dev);
93 int (*offline)(struct device *dev);
94
95 int (*suspend)(struct device *dev, pm_message_t state);
96 int (*resume)(struct device *dev);
97
98 int (*num_vf)(struct device *dev);
99
100 int (*dma_configure)(struct device *dev);
101 void (*dma_cleanup)(struct device *dev);
102
103 const struct dev_pm_ops *pm;
104
105 bool need_parent_lock;
106
107 ANDROID_KABI_RESERVE(1);
108 ANDROID_KABI_RESERVE(2);
109 ANDROID_KABI_RESERVE(3);
110 ANDROID_KABI_RESERVE(4);
111 };
112
113 int __must_check bus_register(const struct bus_type *bus);
114
115 void bus_unregister(const struct bus_type *bus);
116
117 int __must_check bus_rescan_devices(const struct bus_type *bus);
118
119 struct bus_attribute {
120 struct attribute attr;
121 ssize_t (*show)(const struct bus_type *bus, char *buf);
122 ssize_t (*store)(const struct bus_type *bus, const char *buf, size_t count);
123 };
124
125 #define BUS_ATTR_RW(_name) \
126 struct bus_attribute bus_attr_##_name = __ATTR_RW(_name)
127 #define BUS_ATTR_RO(_name) \
128 struct bus_attribute bus_attr_##_name = __ATTR_RO(_name)
129 #define BUS_ATTR_WO(_name) \
130 struct bus_attribute bus_attr_##_name = __ATTR_WO(_name)
131
132 int __must_check bus_create_file(const struct bus_type *bus, struct bus_attribute *attr);
133 void bus_remove_file(const struct bus_type *bus, struct bus_attribute *attr);
134
135 /* Matching function type for drivers/base APIs to find a specific device */
136 typedef int (*device_match_t)(struct device *dev, const void *data);
137
138 /* Generic device matching functions that all busses can use to match with */
139 int device_match_name(struct device *dev, const void *name);
140 int device_match_of_node(struct device *dev, const void *np);
141 int device_match_fwnode(struct device *dev, const void *fwnode);
142 int device_match_devt(struct device *dev, const void *pdevt);
143 int device_match_acpi_dev(struct device *dev, const void *adev);
144 int device_match_acpi_handle(struct device *dev, const void *handle);
145 int device_match_any(struct device *dev, const void *unused);
146
147 /* iterator helpers for buses */
148 int bus_for_each_dev(const struct bus_type *bus, struct device *start, void *data,
149 int (*fn)(struct device *dev, void *data));
150 struct device *bus_find_device(const struct bus_type *bus, struct device *start,
151 const void *data, device_match_t match);
152 /**
153 * bus_find_device_by_name - device iterator for locating a particular device
154 * of a specific name.
155 * @bus: bus type
156 * @start: Device to begin with
157 * @name: name of the device to match
158 */
bus_find_device_by_name(const struct bus_type * bus,struct device * start,const char * name)159 static inline struct device *bus_find_device_by_name(const struct bus_type *bus,
160 struct device *start,
161 const char *name)
162 {
163 return bus_find_device(bus, start, name, device_match_name);
164 }
165
166 /**
167 * bus_find_device_by_of_node : device iterator for locating a particular device
168 * matching the of_node.
169 * @bus: bus type
170 * @np: of_node of the device to match.
171 */
172 static inline struct device *
bus_find_device_by_of_node(const struct bus_type * bus,const struct device_node * np)173 bus_find_device_by_of_node(const struct bus_type *bus, const struct device_node *np)
174 {
175 return bus_find_device(bus, NULL, np, device_match_of_node);
176 }
177
178 /**
179 * bus_find_device_by_fwnode : device iterator for locating a particular device
180 * matching the fwnode.
181 * @bus: bus type
182 * @fwnode: fwnode of the device to match.
183 */
184 static inline struct device *
bus_find_device_by_fwnode(const struct bus_type * bus,const struct fwnode_handle * fwnode)185 bus_find_device_by_fwnode(const struct bus_type *bus, const struct fwnode_handle *fwnode)
186 {
187 return bus_find_device(bus, NULL, fwnode, device_match_fwnode);
188 }
189
190 /**
191 * bus_find_device_by_devt : device iterator for locating a particular device
192 * matching the device type.
193 * @bus: bus type
194 * @devt: device type of the device to match.
195 */
bus_find_device_by_devt(const struct bus_type * bus,dev_t devt)196 static inline struct device *bus_find_device_by_devt(const struct bus_type *bus,
197 dev_t devt)
198 {
199 return bus_find_device(bus, NULL, &devt, device_match_devt);
200 }
201
202 /**
203 * bus_find_next_device - Find the next device after a given device in a
204 * given bus.
205 * @bus: bus type
206 * @cur: device to begin the search with.
207 */
208 static inline struct device *
bus_find_next_device(const struct bus_type * bus,struct device * cur)209 bus_find_next_device(const struct bus_type *bus,struct device *cur)
210 {
211 return bus_find_device(bus, cur, NULL, device_match_any);
212 }
213
214 #ifdef CONFIG_ACPI
215 struct acpi_device;
216
217 /**
218 * bus_find_device_by_acpi_dev : device iterator for locating a particular device
219 * matching the ACPI COMPANION device.
220 * @bus: bus type
221 * @adev: ACPI COMPANION device to match.
222 */
223 static inline struct device *
bus_find_device_by_acpi_dev(const struct bus_type * bus,const struct acpi_device * adev)224 bus_find_device_by_acpi_dev(const struct bus_type *bus, const struct acpi_device *adev)
225 {
226 return bus_find_device(bus, NULL, adev, device_match_acpi_dev);
227 }
228 #else
229 static inline struct device *
bus_find_device_by_acpi_dev(const struct bus_type * bus,const void * adev)230 bus_find_device_by_acpi_dev(const struct bus_type *bus, const void *adev)
231 {
232 return NULL;
233 }
234 #endif
235
236 int bus_for_each_drv(const struct bus_type *bus, struct device_driver *start,
237 void *data, int (*fn)(struct device_driver *, void *));
238 void bus_sort_breadthfirst(const struct bus_type *bus,
239 int (*compare)(const struct device *a,
240 const struct device *b));
241 /*
242 * Bus notifiers: Get notified of addition/removal of devices
243 * and binding/unbinding of drivers to devices.
244 * In the long run, it should be a replacement for the platform
245 * notify hooks.
246 */
247 struct notifier_block;
248
249 int bus_register_notifier(const struct bus_type *bus, struct notifier_block *nb);
250 int bus_unregister_notifier(const struct bus_type *bus, struct notifier_block *nb);
251
252 /**
253 * enum bus_notifier_event - Bus Notifier events that have happened
254 * @BUS_NOTIFY_ADD_DEVICE: device is added to this bus
255 * @BUS_NOTIFY_DEL_DEVICE: device is about to be removed from this bus
256 * @BUS_NOTIFY_REMOVED_DEVICE: device is successfully removed from this bus
257 * @BUS_NOTIFY_BIND_DRIVER: a driver is about to be bound to this device on this bus
258 * @BUS_NOTIFY_BOUND_DRIVER: a driver is successfully bound to this device on this bus
259 * @BUS_NOTIFY_UNBIND_DRIVER: a driver is about to be unbound from this device on this bus
260 * @BUS_NOTIFY_UNBOUND_DRIVER: a driver is successfully unbound from this device on this bus
261 * @BUS_NOTIFY_DRIVER_NOT_BOUND: a driver failed to be bound to this device on this bus
262 *
263 * These are the value passed to a bus notifier when a specific event happens.
264 *
265 * Note that bus notifiers are likely to be called with the device lock already
266 * held by the driver core, so be careful in any notifier callback as to what
267 * you do with the device structure.
268 *
269 * All bus notifiers are called with the target struct device * as an argument.
270 */
271 enum bus_notifier_event {
272 BUS_NOTIFY_ADD_DEVICE,
273 BUS_NOTIFY_DEL_DEVICE,
274 BUS_NOTIFY_REMOVED_DEVICE,
275 BUS_NOTIFY_BIND_DRIVER,
276 BUS_NOTIFY_BOUND_DRIVER,
277 BUS_NOTIFY_UNBIND_DRIVER,
278 BUS_NOTIFY_UNBOUND_DRIVER,
279 BUS_NOTIFY_DRIVER_NOT_BOUND,
280 };
281
282 struct kset *bus_get_kset(const struct bus_type *bus);
283 struct device *bus_get_dev_root(const struct bus_type *bus);
284
285 #endif
286