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 * @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 * @iommu_ops: IOMMU specific operations for this bus, used to attach IOMMU
67 * driver implementations to a bus and allow the driver to do
68 * bus-specific setup
69 * @p: The private data of the driver core, only the driver core can
70 * touch this.
71 * @lock_key: Lock class key for use by the lock validator
72 * @need_parent_lock: When probing or removing a device on this bus, the
73 * device core should lock the device's parent.
74 *
75 * A bus is a channel between the processor and one or more devices. For the
76 * purposes of the device model, all devices are connected via a bus, even if
77 * it is an internal, virtual, "platform" bus. Buses can plug into each other.
78 * A USB controller is usually a PCI device, for example. The device model
79 * represents the actual connections between buses and the devices they control.
80 * A bus is represented by the bus_type structure. It contains the name, the
81 * default attributes, the bus' methods, PM operations, and the driver core's
82 * private data.
83 */
84 struct bus_type {
85 const char *name;
86 const char *dev_name;
87 struct device *dev_root;
88 const struct attribute_group **bus_groups;
89 const struct attribute_group **dev_groups;
90 const struct attribute_group **drv_groups;
91
92 int (*match)(struct device *dev, struct device_driver *drv);
93 int (*uevent)(struct device *dev, struct kobj_uevent_env *env);
94 int (*probe)(struct device *dev);
95 void (*sync_state)(struct device *dev);
96 void (*remove)(struct device *dev);
97 void (*shutdown)(struct device *dev);
98
99 int (*online)(struct device *dev);
100 int (*offline)(struct device *dev);
101
102 int (*suspend)(struct device *dev, pm_message_t state);
103 int (*resume)(struct device *dev);
104
105 int (*num_vf)(struct device *dev);
106
107 int (*dma_configure)(struct device *dev);
108 void (*dma_cleanup)(struct device *dev);
109
110 const struct dev_pm_ops *pm;
111
112 const struct iommu_ops *iommu_ops;
113
114 struct subsys_private *p;
115 struct lock_class_key lock_key;
116
117 bool need_parent_lock;
118 };
119
120 extern int __must_check bus_register(struct bus_type *bus);
121
122 extern void bus_unregister(struct bus_type *bus);
123
124 extern int __must_check bus_rescan_devices(struct bus_type *bus);
125
126 struct bus_attribute {
127 struct attribute attr;
128 ssize_t (*show)(struct bus_type *bus, char *buf);
129 ssize_t (*store)(struct bus_type *bus, const char *buf, size_t count);
130 };
131
132 #define BUS_ATTR_RW(_name) \
133 struct bus_attribute bus_attr_##_name = __ATTR_RW(_name)
134 #define BUS_ATTR_RO(_name) \
135 struct bus_attribute bus_attr_##_name = __ATTR_RO(_name)
136 #define BUS_ATTR_WO(_name) \
137 struct bus_attribute bus_attr_##_name = __ATTR_WO(_name)
138
139 extern int __must_check bus_create_file(struct bus_type *,
140 struct bus_attribute *);
141 extern void bus_remove_file(struct bus_type *, struct bus_attribute *);
142
143 /* Generic device matching functions that all busses can use to match with */
144 int device_match_name(struct device *dev, const void *name);
145 int device_match_of_node(struct device *dev, const void *np);
146 int device_match_fwnode(struct device *dev, const void *fwnode);
147 int device_match_devt(struct device *dev, const void *pdevt);
148 int device_match_acpi_dev(struct device *dev, const void *adev);
149 int device_match_acpi_handle(struct device *dev, const void *handle);
150 int device_match_any(struct device *dev, const void *unused);
151
152 /* iterator helpers for buses */
153 struct subsys_dev_iter {
154 struct klist_iter ki;
155 const struct device_type *type;
156 };
157 void subsys_dev_iter_init(struct subsys_dev_iter *iter,
158 struct bus_type *subsys,
159 struct device *start,
160 const struct device_type *type);
161 struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter);
162 void subsys_dev_iter_exit(struct subsys_dev_iter *iter);
163
164 int bus_for_each_dev(struct bus_type *bus, struct device *start, void *data,
165 int (*fn)(struct device *dev, void *data));
166 struct device *bus_find_device(struct bus_type *bus, struct device *start,
167 const void *data,
168 int (*match)(struct device *dev, const void *data));
169 /**
170 * bus_find_device_by_name - device iterator for locating a particular device
171 * of a specific name.
172 * @bus: bus type
173 * @start: Device to begin with
174 * @name: name of the device to match
175 */
bus_find_device_by_name(struct bus_type * bus,struct device * start,const char * name)176 static inline struct device *bus_find_device_by_name(struct bus_type *bus,
177 struct device *start,
178 const char *name)
179 {
180 return bus_find_device(bus, start, name, device_match_name);
181 }
182
183 /**
184 * bus_find_device_by_of_node : device iterator for locating a particular device
185 * matching the of_node.
186 * @bus: bus type
187 * @np: of_node of the device to match.
188 */
189 static inline struct device *
bus_find_device_by_of_node(struct bus_type * bus,const struct device_node * np)190 bus_find_device_by_of_node(struct bus_type *bus, const struct device_node *np)
191 {
192 return bus_find_device(bus, NULL, np, device_match_of_node);
193 }
194
195 /**
196 * bus_find_device_by_fwnode : device iterator for locating a particular device
197 * matching the fwnode.
198 * @bus: bus type
199 * @fwnode: fwnode of the device to match.
200 */
201 static inline struct device *
bus_find_device_by_fwnode(struct bus_type * bus,const struct fwnode_handle * fwnode)202 bus_find_device_by_fwnode(struct bus_type *bus, const struct fwnode_handle *fwnode)
203 {
204 return bus_find_device(bus, NULL, fwnode, device_match_fwnode);
205 }
206
207 /**
208 * bus_find_device_by_devt : device iterator for locating a particular device
209 * matching the device type.
210 * @bus: bus type
211 * @devt: device type of the device to match.
212 */
bus_find_device_by_devt(struct bus_type * bus,dev_t devt)213 static inline struct device *bus_find_device_by_devt(struct bus_type *bus,
214 dev_t devt)
215 {
216 return bus_find_device(bus, NULL, &devt, device_match_devt);
217 }
218
219 /**
220 * bus_find_next_device - Find the next device after a given device in a
221 * given bus.
222 * @bus: bus type
223 * @cur: device to begin the search with.
224 */
225 static inline struct device *
bus_find_next_device(struct bus_type * bus,struct device * cur)226 bus_find_next_device(struct bus_type *bus,struct device *cur)
227 {
228 return bus_find_device(bus, cur, NULL, device_match_any);
229 }
230
231 #ifdef CONFIG_ACPI
232 struct acpi_device;
233
234 /**
235 * bus_find_device_by_acpi_dev : device iterator for locating a particular device
236 * matching the ACPI COMPANION device.
237 * @bus: bus type
238 * @adev: ACPI COMPANION device to match.
239 */
240 static inline struct device *
bus_find_device_by_acpi_dev(struct bus_type * bus,const struct acpi_device * adev)241 bus_find_device_by_acpi_dev(struct bus_type *bus, const struct acpi_device *adev)
242 {
243 return bus_find_device(bus, NULL, adev, device_match_acpi_dev);
244 }
245 #else
246 static inline struct device *
bus_find_device_by_acpi_dev(struct bus_type * bus,const void * adev)247 bus_find_device_by_acpi_dev(struct bus_type *bus, const void *adev)
248 {
249 return NULL;
250 }
251 #endif
252
253 struct device *subsys_find_device_by_id(struct bus_type *bus, unsigned int id,
254 struct device *hint);
255 int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
256 void *data, int (*fn)(struct device_driver *, void *));
257 void bus_sort_breadthfirst(struct bus_type *bus,
258 int (*compare)(const struct device *a,
259 const struct device *b));
260 /*
261 * Bus notifiers: Get notified of addition/removal of devices
262 * and binding/unbinding of drivers to devices.
263 * In the long run, it should be a replacement for the platform
264 * notify hooks.
265 */
266 struct notifier_block;
267
268 extern int bus_register_notifier(struct bus_type *bus,
269 struct notifier_block *nb);
270 extern int bus_unregister_notifier(struct bus_type *bus,
271 struct notifier_block *nb);
272
273 /* All 4 notifers below get called with the target struct device *
274 * as an argument. Note that those functions are likely to be called
275 * with the device lock held in the core, so be careful.
276 */
277 #define BUS_NOTIFY_ADD_DEVICE 0x00000001 /* device added */
278 #define BUS_NOTIFY_DEL_DEVICE 0x00000002 /* device to be removed */
279 #define BUS_NOTIFY_REMOVED_DEVICE 0x00000003 /* device removed */
280 #define BUS_NOTIFY_BIND_DRIVER 0x00000004 /* driver about to be
281 bound */
282 #define BUS_NOTIFY_BOUND_DRIVER 0x00000005 /* driver bound to device */
283 #define BUS_NOTIFY_UNBIND_DRIVER 0x00000006 /* driver about to be
284 unbound */
285 #define BUS_NOTIFY_UNBOUND_DRIVER 0x00000007 /* driver is unbound
286 from the device */
287 #define BUS_NOTIFY_DRIVER_NOT_BOUND 0x00000008 /* driver fails to be bound */
288
289 extern struct kset *bus_get_kset(struct bus_type *bus);
290 extern struct klist *bus_get_device_klist(struct bus_type *bus);
291
292 #endif
293