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 <[email protected]> 6 * Copyright (c) 2004-2009 Greg Kroah-Hartman <[email protected]> 7 * Copyright (c) 2008-2009 Novell Inc. 8 * Copyright (c) 2012-2019 Greg Kroah-Hartman <[email protected]> 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)(const 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; 115 116 bool need_parent_lock; 117 }; 118 119 extern int __must_check bus_register(struct bus_type *bus); 120 121 extern void bus_unregister(struct bus_type *bus); 122 123 extern int __must_check bus_rescan_devices(struct bus_type *bus); 124 125 struct bus_attribute { 126 struct attribute attr; 127 ssize_t (*show)(struct bus_type *bus, char *buf); 128 ssize_t (*store)(struct bus_type *bus, const char *buf, size_t count); 129 }; 130 131 #define BUS_ATTR_RW(_name) \ 132 struct bus_attribute bus_attr_##_name = __ATTR_RW(_name) 133 #define BUS_ATTR_RO(_name) \ 134 struct bus_attribute bus_attr_##_name = __ATTR_RO(_name) 135 #define BUS_ATTR_WO(_name) \ 136 struct bus_attribute bus_attr_##_name = __ATTR_WO(_name) 137 138 extern int __must_check bus_create_file(struct bus_type *, 139 struct bus_attribute *); 140 extern void bus_remove_file(struct bus_type *, struct bus_attribute *); 141 142 /* Generic device matching functions that all busses can use to match with */ 143 int device_match_name(struct device *dev, const void *name); 144 int device_match_of_node(struct device *dev, const void *np); 145 int device_match_fwnode(struct device *dev, const void *fwnode); 146 int device_match_devt(struct device *dev, const void *pdevt); 147 int device_match_acpi_dev(struct device *dev, const void *adev); 148 int device_match_acpi_handle(struct device *dev, const void *handle); 149 int device_match_any(struct device *dev, const void *unused); 150 151 /* iterator helpers for buses */ 152 int bus_for_each_dev(const struct bus_type *bus, struct device *start, void *data, 153 int (*fn)(struct device *dev, void *data)); 154 struct device *bus_find_device(const struct bus_type *bus, struct device *start, 155 const void *data, 156 int (*match)(struct device *dev, const void *data)); 157 /** 158 * bus_find_device_by_name - device iterator for locating a particular device 159 * of a specific name. 160 * @bus: bus type 161 * @start: Device to begin with 162 * @name: name of the device to match 163 */ 164 static inline struct device *bus_find_device_by_name(const struct bus_type *bus, 165 struct device *start, 166 const char *name) 167 { 168 return bus_find_device(bus, start, name, device_match_name); 169 } 170 171 /** 172 * bus_find_device_by_of_node : device iterator for locating a particular device 173 * matching the of_node. 174 * @bus: bus type 175 * @np: of_node of the device to match. 176 */ 177 static inline struct device * 178 bus_find_device_by_of_node(const struct bus_type *bus, const struct device_node *np) 179 { 180 return bus_find_device(bus, NULL, np, device_match_of_node); 181 } 182 183 /** 184 * bus_find_device_by_fwnode : device iterator for locating a particular device 185 * matching the fwnode. 186 * @bus: bus type 187 * @fwnode: fwnode of the device to match. 188 */ 189 static inline struct device * 190 bus_find_device_by_fwnode(const struct bus_type *bus, const struct fwnode_handle *fwnode) 191 { 192 return bus_find_device(bus, NULL, fwnode, device_match_fwnode); 193 } 194 195 /** 196 * bus_find_device_by_devt : device iterator for locating a particular device 197 * matching the device type. 198 * @bus: bus type 199 * @devt: device type of the device to match. 200 */ 201 static inline struct device *bus_find_device_by_devt(const struct bus_type *bus, 202 dev_t devt) 203 { 204 return bus_find_device(bus, NULL, &devt, device_match_devt); 205 } 206 207 /** 208 * bus_find_next_device - Find the next device after a given device in a 209 * given bus. 210 * @bus: bus type 211 * @cur: device to begin the search with. 212 */ 213 static inline struct device * 214 bus_find_next_device(const struct bus_type *bus,struct device *cur) 215 { 216 return bus_find_device(bus, cur, NULL, device_match_any); 217 } 218 219 #ifdef CONFIG_ACPI 220 struct acpi_device; 221 222 /** 223 * bus_find_device_by_acpi_dev : device iterator for locating a particular device 224 * matching the ACPI COMPANION device. 225 * @bus: bus type 226 * @adev: ACPI COMPANION device to match. 227 */ 228 static inline struct device * 229 bus_find_device_by_acpi_dev(const struct bus_type *bus, const struct acpi_device *adev) 230 { 231 return bus_find_device(bus, NULL, adev, device_match_acpi_dev); 232 } 233 #else 234 static inline struct device * 235 bus_find_device_by_acpi_dev(const struct bus_type *bus, const void *adev) 236 { 237 return NULL; 238 } 239 #endif 240 241 int bus_for_each_drv(const struct bus_type *bus, struct device_driver *start, 242 void *data, int (*fn)(struct device_driver *, void *)); 243 void bus_sort_breadthfirst(struct bus_type *bus, 244 int (*compare)(const struct device *a, 245 const struct device *b)); 246 /* 247 * Bus notifiers: Get notified of addition/removal of devices 248 * and binding/unbinding of drivers to devices. 249 * In the long run, it should be a replacement for the platform 250 * notify hooks. 251 */ 252 struct notifier_block; 253 254 extern int bus_register_notifier(struct bus_type *bus, 255 struct notifier_block *nb); 256 extern int bus_unregister_notifier(struct bus_type *bus, 257 struct notifier_block *nb); 258 259 /** 260 * enum bus_notifier_event - Bus Notifier events that have happened 261 * @BUS_NOTIFY_ADD_DEVICE: device is added to this bus 262 * @BUS_NOTIFY_DEL_DEVICE: device is about to be removed from this bus 263 * @BUS_NOTIFY_REMOVED_DEVICE: device is successfully removed from this bus 264 * @BUS_NOTIFY_BIND_DRIVER: a driver is about to be bound to this device on this bus 265 * @BUS_NOTIFY_BOUND_DRIVER: a driver is successfully bound to this device on this bus 266 * @BUS_NOTIFY_UNBIND_DRIVER: a driver is about to be unbound from this device on this bus 267 * @BUS_NOTIFY_UNBOUND_DRIVER: a driver is successfully unbound from this device on this bus 268 * @BUS_NOTIFY_DRIVER_NOT_BOUND: a driver failed to be bound to this device on this bus 269 * 270 * These are the value passed to a bus notifier when a specific event happens. 271 * 272 * Note that bus notifiers are likely to be called with the device lock already 273 * held by the driver core, so be careful in any notifier callback as to what 274 * you do with the device structure. 275 * 276 * All bus notifiers are called with the target struct device * as an argument. 277 */ 278 enum bus_notifier_event { 279 BUS_NOTIFY_ADD_DEVICE, 280 BUS_NOTIFY_DEL_DEVICE, 281 BUS_NOTIFY_REMOVED_DEVICE, 282 BUS_NOTIFY_BIND_DRIVER, 283 BUS_NOTIFY_BOUND_DRIVER, 284 BUS_NOTIFY_UNBIND_DRIVER, 285 BUS_NOTIFY_UNBOUND_DRIVER, 286 BUS_NOTIFY_DRIVER_NOT_BOUND, 287 }; 288 289 extern struct kset *bus_get_kset(struct bus_type *bus); 290 291 #endif 292