include/linux/device/bus.h

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