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 * Note: This callback may be invoked with or without the device
39 * lock held.
40 * @uevent: Called when a device is added, removed, or a few other things
41 * that generate uevents to add the environment variables.
42 * @probe: Called when a new device or driver add to this bus, and callback
43 * the specific driver's probe to initial the matched device.
44 * @sync_state: Called to sync device state to software state after all the
45 * state tracking consumers linked to this device (present at
46 * the time of late_initcall) have successfully bound to a
47 * driver. If the device has no consumers, this function will
48 * be called at late_initcall_sync level. If the device has
49 * consumers that are never bound to a driver, this function
50 * will never get called until they do.
51 * @remove: Called when a device removed from this bus.
52 * @shutdown: Called at shut-down time to quiesce the device.
53 * @irq_get_affinity: Get IRQ affinity mask for the device on this bus.
54 *
55 * @online: Called to put the device back online (after offlining it).
56 * @offline: Called to put the device offline for hot-removal. May fail.
57 *
58 * @suspend: Called when a device on this bus wants to go to sleep mode.
59 * @resume: Called to bring a device on this bus out of sleep mode.
60 * @num_vf: Called to find out how many virtual functions a device on this
61 * bus supports.
62 * @dma_configure: Called to setup DMA configuration on a device on
63 * this bus.
64 * @dma_cleanup: Called to cleanup DMA configuration on a device on
65 * this bus.
66 * @pm: Power management operations of this bus, callback the specific
67 * device driver's pm-ops.
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, const 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 const struct cpumask *(*irq_get_affinity)(struct device *dev,
94 unsigned int irq_vec);
95
96 int (*online)(struct device *dev);
97 int (*offline)(struct device *dev);
98
99 int (*suspend)(struct device *dev, pm_message_t state);
100 int (*resume)(struct device *dev);
101
102 int (*num_vf)(struct device *dev);
103
104 int (*dma_configure)(struct device *dev);
105 void (*dma_cleanup)(struct device *dev);
106
107 const struct dev_pm_ops *pm;
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 /* Matching function type for drivers/base APIs to find a specific device */
135 typedef int (*device_match_t)(struct device *dev, const void *data);
136
137 /* Generic device matching functions that all busses can use to match with */
138 int device_match_name(struct device *dev, const void *name);
139 int device_match_type(struct device *dev, const void *type);
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 /* Device iterating function type for various driver core for_each APIs */
148 typedef int (*device_iter_t)(struct device *dev, void *data);
149
150 /* iterator helpers for buses */
151 int bus_for_each_dev(const struct bus_type *bus, struct device *start,
152 void *data, device_iter_t fn);
153 struct device *bus_find_device(const struct bus_type *bus, struct device *start,
154 const void *data, device_match_t match);
155 struct device *bus_find_device_reverse(const struct bus_type *bus,
156 struct device *start, const void *data,
157 device_match_t match);
158 /**
159 * bus_find_device_by_name - device iterator for locating a particular device
160 * of a specific name.
161 * @bus: bus type
162 * @start: Device to begin with
163 * @name: name of the device to match
164 */
bus_find_device_by_name(const struct bus_type * bus,struct device * start,const char * name)165 static inline struct device *bus_find_device_by_name(const struct bus_type *bus,
166 struct device *start,
167 const char *name)
168 {
169 return bus_find_device(bus, start, name, device_match_name);
170 }
171
172 /**
173 * bus_find_device_by_of_node : device iterator for locating a particular device
174 * matching the of_node.
175 * @bus: bus type
176 * @np: of_node of the device to match.
177 */
178 static inline struct device *
bus_find_device_by_of_node(const struct bus_type * bus,const struct device_node * np)179 bus_find_device_by_of_node(const struct bus_type *bus, const struct device_node *np)
180 {
181 return bus_find_device(bus, NULL, np, device_match_of_node);
182 }
183
184 /**
185 * bus_find_device_by_fwnode : device iterator for locating a particular device
186 * matching the fwnode.
187 * @bus: bus type
188 * @fwnode: fwnode of the device to match.
189 */
190 static inline struct device *
bus_find_device_by_fwnode(const struct bus_type * bus,const struct fwnode_handle * fwnode)191 bus_find_device_by_fwnode(const struct bus_type *bus, const struct fwnode_handle *fwnode)
192 {
193 return bus_find_device(bus, NULL, fwnode, device_match_fwnode);
194 }
195
196 /**
197 * bus_find_device_by_devt : device iterator for locating a particular device
198 * matching the device type.
199 * @bus: bus type
200 * @devt: device type of the device to match.
201 */
bus_find_device_by_devt(const struct bus_type * bus,dev_t devt)202 static inline struct device *bus_find_device_by_devt(const struct bus_type *bus,
203 dev_t devt)
204 {
205 return bus_find_device(bus, NULL, &devt, device_match_devt);
206 }
207
208 /**
209 * bus_find_next_device - Find the next device after a given device in a
210 * given bus.
211 * @bus: bus type
212 * @cur: device to begin the search with.
213 */
214 static inline struct device *
bus_find_next_device(const struct bus_type * bus,struct device * cur)215 bus_find_next_device(const struct bus_type *bus,struct device *cur)
216 {
217 return bus_find_device(bus, cur, NULL, device_match_any);
218 }
219
220 struct acpi_device;
221
222 #ifdef CONFIG_ACPI
223 /**
224 * bus_find_device_by_acpi_dev : device iterator for locating a particular device
225 * matching the ACPI COMPANION device.
226 * @bus: bus type
227 * @adev: ACPI COMPANION device to match.
228 */
229 static inline struct device *
bus_find_device_by_acpi_dev(const struct bus_type * bus,const struct acpi_device * adev)230 bus_find_device_by_acpi_dev(const struct bus_type *bus, const struct acpi_device *adev)
231 {
232 return bus_find_device(bus, NULL, adev, device_match_acpi_dev);
233 }
234 #else
235 static inline struct device *
bus_find_device_by_acpi_dev(const struct bus_type * bus,const struct acpi_device * adev)236 bus_find_device_by_acpi_dev(const struct bus_type *bus, const struct acpi_device *adev)
237 {
238 return NULL;
239 }
240 #endif
241
242 int bus_for_each_drv(const struct bus_type *bus, struct device_driver *start,
243 void *data, int (*fn)(struct device_driver *, void *));
244 void bus_sort_breadthfirst(const struct bus_type *bus,
245 int (*compare)(const struct device *a,
246 const struct device *b));
247 /*
248 * Bus notifiers: Get notified of addition/removal of devices
249 * and binding/unbinding of drivers to devices.
250 * In the long run, it should be a replacement for the platform
251 * notify hooks.
252 */
253 struct notifier_block;
254
255 int bus_register_notifier(const struct bus_type *bus, struct notifier_block *nb);
256 int bus_unregister_notifier(const struct bus_type *bus, struct notifier_block *nb);
257
258 /**
259 * enum bus_notifier_event - Bus Notifier events that have happened
260 * @BUS_NOTIFY_ADD_DEVICE: device is added to this bus
261 * @BUS_NOTIFY_DEL_DEVICE: device is about to be removed from this bus
262 * @BUS_NOTIFY_REMOVED_DEVICE: device is successfully removed from this bus
263 * @BUS_NOTIFY_BIND_DRIVER: a driver is about to be bound to this device on this bus
264 * @BUS_NOTIFY_BOUND_DRIVER: a driver is successfully bound to this device on this bus
265 * @BUS_NOTIFY_UNBIND_DRIVER: a driver is about to be unbound from this device on this bus
266 * @BUS_NOTIFY_UNBOUND_DRIVER: a driver is successfully unbound from this device on this bus
267 * @BUS_NOTIFY_DRIVER_NOT_BOUND: a driver failed to be bound to this device on this bus
268 *
269 * These are the value passed to a bus notifier when a specific event happens.
270 *
271 * Note that bus notifiers are likely to be called with the device lock already
272 * held by the driver core, so be careful in any notifier callback as to what
273 * you do with the device structure.
274 *
275 * All bus notifiers are called with the target struct device * as an argument.
276 */
277 enum bus_notifier_event {
278 BUS_NOTIFY_ADD_DEVICE,
279 BUS_NOTIFY_DEL_DEVICE,
280 BUS_NOTIFY_REMOVED_DEVICE,
281 BUS_NOTIFY_BIND_DRIVER,
282 BUS_NOTIFY_BOUND_DRIVER,
283 BUS_NOTIFY_UNBIND_DRIVER,
284 BUS_NOTIFY_UNBOUND_DRIVER,
285 BUS_NOTIFY_DRIVER_NOT_BOUND,
286 };
287
288 struct kset *bus_get_kset(const struct bus_type *bus);
289 struct device *bus_get_dev_root(const struct bus_type *bus);
290
291 #endif
292