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 * @pm: Power management operations of this bus, callback the specific 63 * device driver's pm-ops. 64 * @iommu_ops: IOMMU specific operations for this bus, used to attach IOMMU 65 * driver implementations to a bus and allow the driver to do 66 * bus-specific setup 67 * @p: The private data of the driver core, only the driver core can 68 * touch this. 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)(struct device *dev, struct kobj_uevent_env *env); 92 int (*probe)(struct device *dev); 93 void (*sync_state)(struct device *dev); 94 int (*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); 106 107 const struct dev_pm_ops *pm; 108 109 const struct iommu_ops *iommu_ops; 110 111 struct subsys_private *p; 112 struct lock_class_key lock_key; 113 114 bool need_parent_lock; 115 }; 116 117 extern int __must_check bus_register(struct bus_type *bus); 118 119 extern void bus_unregister(struct bus_type *bus); 120 121 extern int __must_check bus_rescan_devices(struct bus_type *bus); 122 123 struct bus_attribute { 124 struct attribute attr; 125 ssize_t (*show)(struct bus_type *bus, char *buf); 126 ssize_t (*store)(struct bus_type *bus, const char *buf, size_t count); 127 }; 128 129 #define BUS_ATTR_RW(_name) \ 130 struct bus_attribute bus_attr_##_name = __ATTR_RW(_name) 131 #define BUS_ATTR_RO(_name) \ 132 struct bus_attribute bus_attr_##_name = __ATTR_RO(_name) 133 #define BUS_ATTR_WO(_name) \ 134 struct bus_attribute bus_attr_##_name = __ATTR_WO(_name) 135 136 extern int __must_check bus_create_file(struct bus_type *, 137 struct bus_attribute *); 138 extern void bus_remove_file(struct bus_type *, struct bus_attribute *); 139 140 /* Generic device matching functions that all busses can use to match with */ 141 int device_match_name(struct device *dev, const void *name); 142 int device_match_of_node(struct device *dev, const void *np); 143 int device_match_fwnode(struct device *dev, const void *fwnode); 144 int device_match_devt(struct device *dev, const void *pdevt); 145 int device_match_acpi_dev(struct device *dev, const void *adev); 146 int device_match_any(struct device *dev, const void *unused); 147 148 /* iterator helpers for buses */ 149 struct subsys_dev_iter { 150 struct klist_iter ki; 151 const struct device_type *type; 152 }; 153 void subsys_dev_iter_init(struct subsys_dev_iter *iter, 154 struct bus_type *subsys, 155 struct device *start, 156 const struct device_type *type); 157 struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter); 158 void subsys_dev_iter_exit(struct subsys_dev_iter *iter); 159 160 int bus_for_each_dev(struct bus_type *bus, struct device *start, void *data, 161 int (*fn)(struct device *dev, void *data)); 162 struct device *bus_find_device(struct bus_type *bus, struct device *start, 163 const void *data, 164 int (*match)(struct device *dev, const void *data)); 165 /** 166 * bus_find_device_by_name - device iterator for locating a particular device 167 * of a specific name. 168 * @bus: bus type 169 * @start: Device to begin with 170 * @name: name of the device to match 171 */ 172 static inline struct device *bus_find_device_by_name(struct bus_type *bus, 173 struct device *start, 174 const char *name) 175 { 176 return bus_find_device(bus, start, name, device_match_name); 177 } 178 179 /** 180 * bus_find_device_by_of_node : device iterator for locating a particular device 181 * matching the of_node. 182 * @bus: bus type 183 * @np: of_node of the device to match. 184 */ 185 static inline struct device * 186 bus_find_device_by_of_node(struct bus_type *bus, const struct device_node *np) 187 { 188 return bus_find_device(bus, NULL, np, device_match_of_node); 189 } 190 191 /** 192 * bus_find_device_by_fwnode : device iterator for locating a particular device 193 * matching the fwnode. 194 * @bus: bus type 195 * @fwnode: fwnode of the device to match. 196 */ 197 static inline struct device * 198 bus_find_device_by_fwnode(struct bus_type *bus, const struct fwnode_handle *fwnode) 199 { 200 return bus_find_device(bus, NULL, fwnode, device_match_fwnode); 201 } 202 203 /** 204 * bus_find_device_by_devt : device iterator for locating a particular device 205 * matching the device type. 206 * @bus: bus type 207 * @devt: device type of the device to match. 208 */ 209 static inline struct device *bus_find_device_by_devt(struct bus_type *bus, 210 dev_t devt) 211 { 212 return bus_find_device(bus, NULL, &devt, device_match_devt); 213 } 214 215 /** 216 * bus_find_next_device - Find the next device after a given device in a 217 * given bus. 218 * @bus: bus type 219 * @cur: device to begin the search with. 220 */ 221 static inline struct device * 222 bus_find_next_device(struct bus_type *bus,struct device *cur) 223 { 224 return bus_find_device(bus, cur, NULL, device_match_any); 225 } 226 227 #ifdef CONFIG_ACPI 228 struct acpi_device; 229 230 /** 231 * bus_find_device_by_acpi_dev : device iterator for locating a particular device 232 * matching the ACPI COMPANION device. 233 * @bus: bus type 234 * @adev: ACPI COMPANION device to match. 235 */ 236 static inline struct device * 237 bus_find_device_by_acpi_dev(struct bus_type *bus, const struct acpi_device *adev) 238 { 239 return bus_find_device(bus, NULL, adev, device_match_acpi_dev); 240 } 241 #else 242 static inline struct device * 243 bus_find_device_by_acpi_dev(struct bus_type *bus, const void *adev) 244 { 245 return NULL; 246 } 247 #endif 248 249 struct device *subsys_find_device_by_id(struct bus_type *bus, unsigned int id, 250 struct device *hint); 251 int bus_for_each_drv(struct bus_type *bus, struct device_driver *start, 252 void *data, int (*fn)(struct device_driver *, void *)); 253 void bus_sort_breadthfirst(struct bus_type *bus, 254 int (*compare)(const struct device *a, 255 const struct device *b)); 256 /* 257 * Bus notifiers: Get notified of addition/removal of devices 258 * and binding/unbinding of drivers to devices. 259 * In the long run, it should be a replacement for the platform 260 * notify hooks. 261 */ 262 struct notifier_block; 263 264 extern int bus_register_notifier(struct bus_type *bus, 265 struct notifier_block *nb); 266 extern int bus_unregister_notifier(struct bus_type *bus, 267 struct notifier_block *nb); 268 269 /* All 4 notifers below get called with the target struct device * 270 * as an argument. Note that those functions are likely to be called 271 * with the device lock held in the core, so be careful. 272 */ 273 #define BUS_NOTIFY_ADD_DEVICE 0x00000001 /* device added */ 274 #define BUS_NOTIFY_DEL_DEVICE 0x00000002 /* device to be removed */ 275 #define BUS_NOTIFY_REMOVED_DEVICE 0x00000003 /* device removed */ 276 #define BUS_NOTIFY_BIND_DRIVER 0x00000004 /* driver about to be 277 bound */ 278 #define BUS_NOTIFY_BOUND_DRIVER 0x00000005 /* driver bound to device */ 279 #define BUS_NOTIFY_UNBIND_DRIVER 0x00000006 /* driver about to be 280 unbound */ 281 #define BUS_NOTIFY_UNBOUND_DRIVER 0x00000007 /* driver is unbound 282 from the device */ 283 #define BUS_NOTIFY_DRIVER_NOT_BOUND 0x00000008 /* driver fails to be bound */ 284 285 extern struct kset *bus_get_kset(struct bus_type *bus); 286 extern struct klist *bus_get_device_klist(struct bus_type *bus); 287 288 #endif 289