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 void (*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 */
bus_find_device_by_name(struct bus_type * bus,struct device * start,const char * name)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 *
bus_find_device_by_of_node(struct bus_type * bus,const struct device_node * np)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 *
bus_find_device_by_fwnode(struct bus_type * bus,const struct fwnode_handle * fwnode)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 */
bus_find_device_by_devt(struct bus_type * bus,dev_t devt)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 *
bus_find_next_device(struct bus_type * bus,struct device * cur)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 *
bus_find_device_by_acpi_dev(struct bus_type * bus,const struct acpi_device * adev)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 *
bus_find_device_by_acpi_dev(struct bus_type * bus,const void * adev)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
289
