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 * @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)(const 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 void (*dma_cleanup)(struct device *dev); 107 108 const struct dev_pm_ops *pm; 109 110 const struct iommu_ops *iommu_ops; 111 112 bool need_parent_lock; 113 }; 114 115 extern int __must_check bus_register(struct bus_type *bus); 116 117 extern void bus_unregister(const struct bus_type *bus); 118 119 extern int __must_check bus_rescan_devices(struct bus_type *bus); 120 121 struct bus_attribute { 122 struct attribute attr; 123 ssize_t (*show)(struct bus_type *bus, char *buf); 124 ssize_t (*store)(struct bus_type *bus, const char *buf, size_t count); 125 }; 126 127 #define BUS_ATTR_RW(_name) \ 128 struct bus_attribute bus_attr_##_name = __ATTR_RW(_name) 129 #define BUS_ATTR_RO(_name) \ 130 struct bus_attribute bus_attr_##_name = __ATTR_RO(_name) 131 #define BUS_ATTR_WO(_name) \ 132 struct bus_attribute bus_attr_##_name = __ATTR_WO(_name) 133 134 int __must_check bus_create_file(const struct bus_type *bus, struct bus_attribute *attr); 135 void bus_remove_file(const struct bus_type *bus, struct bus_attribute *attr); 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_of_node(struct device *dev, const void *np); 140 int device_match_fwnode(struct device *dev, const void *fwnode); 141 int device_match_devt(struct device *dev, const void *pdevt); 142 int device_match_acpi_dev(struct device *dev, const void *adev); 143 int device_match_acpi_handle(struct device *dev, const void *handle); 144 int device_match_any(struct device *dev, const void *unused); 145 146 /* iterator helpers for buses */ 147 int bus_for_each_dev(const struct bus_type *bus, struct device *start, void *data, 148 int (*fn)(struct device *dev, void *data)); 149 struct device *bus_find_device(const struct bus_type *bus, struct device *start, 150 const void *data, 151 int (*match)(struct device *dev, const void *data)); 152 /** 153 * bus_find_device_by_name - device iterator for locating a particular device 154 * of a specific name. 155 * @bus: bus type 156 * @start: Device to begin with 157 * @name: name of the device to match 158 */ 159 static inline struct device *bus_find_device_by_name(const struct bus_type *bus, 160 struct device *start, 161 const char *name) 162 { 163 return bus_find_device(bus, start, name, device_match_name); 164 } 165 166 /** 167 * bus_find_device_by_of_node : device iterator for locating a particular device 168 * matching the of_node. 169 * @bus: bus type 170 * @np: of_node of the device to match. 171 */ 172 static inline struct device * 173 bus_find_device_by_of_node(const struct bus_type *bus, const struct device_node *np) 174 { 175 return bus_find_device(bus, NULL, np, device_match_of_node); 176 } 177 178 /** 179 * bus_find_device_by_fwnode : device iterator for locating a particular device 180 * matching the fwnode. 181 * @bus: bus type 182 * @fwnode: fwnode of the device to match. 183 */ 184 static inline struct device * 185 bus_find_device_by_fwnode(const struct bus_type *bus, const struct fwnode_handle *fwnode) 186 { 187 return bus_find_device(bus, NULL, fwnode, device_match_fwnode); 188 } 189 190 /** 191 * bus_find_device_by_devt : device iterator for locating a particular device 192 * matching the device type. 193 * @bus: bus type 194 * @devt: device type of the device to match. 195 */ 196 static inline struct device *bus_find_device_by_devt(const struct bus_type *bus, 197 dev_t devt) 198 { 199 return bus_find_device(bus, NULL, &devt, device_match_devt); 200 } 201 202 /** 203 * bus_find_next_device - Find the next device after a given device in a 204 * given bus. 205 * @bus: bus type 206 * @cur: device to begin the search with. 207 */ 208 static inline struct device * 209 bus_find_next_device(const struct bus_type *bus,struct device *cur) 210 { 211 return bus_find_device(bus, cur, NULL, device_match_any); 212 } 213 214 #ifdef CONFIG_ACPI 215 struct acpi_device; 216 217 /** 218 * bus_find_device_by_acpi_dev : device iterator for locating a particular device 219 * matching the ACPI COMPANION device. 220 * @bus: bus type 221 * @adev: ACPI COMPANION device to match. 222 */ 223 static inline struct device * 224 bus_find_device_by_acpi_dev(const struct bus_type *bus, const struct acpi_device *adev) 225 { 226 return bus_find_device(bus, NULL, adev, device_match_acpi_dev); 227 } 228 #else 229 static inline struct device * 230 bus_find_device_by_acpi_dev(const struct bus_type *bus, const void *adev) 231 { 232 return NULL; 233 } 234 #endif 235 236 int bus_for_each_drv(const struct bus_type *bus, struct device_driver *start, 237 void *data, int (*fn)(struct device_driver *, void *)); 238 void bus_sort_breadthfirst(struct bus_type *bus, 239 int (*compare)(const struct device *a, 240 const struct device *b)); 241 /* 242 * Bus notifiers: Get notified of addition/removal of devices 243 * and binding/unbinding of drivers to devices. 244 * In the long run, it should be a replacement for the platform 245 * notify hooks. 246 */ 247 struct notifier_block; 248 249 extern int bus_register_notifier(const struct bus_type *bus, 250 struct notifier_block *nb); 251 extern int bus_unregister_notifier(const struct bus_type *bus, 252 struct notifier_block *nb); 253 254 /** 255 * enum bus_notifier_event - Bus Notifier events that have happened 256 * @BUS_NOTIFY_ADD_DEVICE: device is added to this bus 257 * @BUS_NOTIFY_DEL_DEVICE: device is about to be removed from this bus 258 * @BUS_NOTIFY_REMOVED_DEVICE: device is successfully removed from this bus 259 * @BUS_NOTIFY_BIND_DRIVER: a driver is about to be bound to this device on this bus 260 * @BUS_NOTIFY_BOUND_DRIVER: a driver is successfully bound to this device on this bus 261 * @BUS_NOTIFY_UNBIND_DRIVER: a driver is about to be unbound from this device on this bus 262 * @BUS_NOTIFY_UNBOUND_DRIVER: a driver is successfully unbound from this device on this bus 263 * @BUS_NOTIFY_DRIVER_NOT_BOUND: a driver failed to be bound to this device on this bus 264 * 265 * These are the value passed to a bus notifier when a specific event happens. 266 * 267 * Note that bus notifiers are likely to be called with the device lock already 268 * held by the driver core, so be careful in any notifier callback as to what 269 * you do with the device structure. 270 * 271 * All bus notifiers are called with the target struct device * as an argument. 272 */ 273 enum bus_notifier_event { 274 BUS_NOTIFY_ADD_DEVICE, 275 BUS_NOTIFY_DEL_DEVICE, 276 BUS_NOTIFY_REMOVED_DEVICE, 277 BUS_NOTIFY_BIND_DRIVER, 278 BUS_NOTIFY_BOUND_DRIVER, 279 BUS_NOTIFY_UNBIND_DRIVER, 280 BUS_NOTIFY_UNBOUND_DRIVER, 281 BUS_NOTIFY_DRIVER_NOT_BOUND, 282 }; 283 284 extern struct kset *bus_get_kset(const struct bus_type *bus); 285 struct device *bus_get_dev_root(const struct bus_type *bus); 286 287 #endif 288