| 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 |