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 */ 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 * 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 * 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 */ 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 * 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 * 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 * 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