// SPDX-License-Identifier: GPL-2.0 /* * bus.h - the bus-specific portions of the driver model * * Copyright (c) 2001-2003 Patrick Mochel <[email protected]> * Copyright (c) 2004-2009 Greg Kroah-Hartman <[email protected]> * Copyright (c) 2008-2009 Novell Inc. * Copyright (c) 2012-2019 Greg Kroah-Hartman <[email protected]> * Copyright (c) 2012-2019 Linux Foundation * * See Documentation/driver-api/driver-model/ for more information. */ #ifndef _DEVICE_BUS_H_ #define _DEVICE_BUS_H_ #include <linux/kobject.h> #include <linux/klist.h> #include <linux/pm.h> struct device_driver; struct fwnode_handle; /** * struct bus_type - The bus type of the device * * @name: The name of the bus. * @dev_name: Used for subsystems to enumerate devices like ("foo%u", dev->id). * @bus_groups: Default attributes of the bus. * @dev_groups: Default attributes of the devices on the bus. * @drv_groups: Default attributes of the device drivers on the bus. * @match: Called, perhaps multiple times, whenever a new device or driver * is added for this bus. It should return a positive value if the * given device can be handled by the given driver and zero * otherwise. It may also return error code if determining that * the driver supports the device is not possible. In case of * -EPROBE_DEFER it will queue the device for deferred probing. * @uevent: Called when a device is added, removed, or a few other things * that generate uevents to add the environment variables. * @probe: Called when a new device or driver add to this bus, and callback * the specific driver's probe to initial the matched device. * @sync_state: Called to sync device state to software state after all the * state tracking consumers linked to this device (present at * the time of late_initcall) have successfully bound to a * driver. If the device has no consumers, this function will * be called at late_initcall_sync level. If the device has * consumers that are never bound to a driver, this function * will never get called until they do. * @remove: Called when a device removed from this bus. * @shutdown: Called at shut-down time to quiesce the device. * * @online: Called to put the device back online (after offlining it). * @offline: Called to put the device offline for hot-removal. May fail. * * @suspend: Called when a device on this bus wants to go to sleep mode. * @resume: Called to bring a device on this bus out of sleep mode. * @num_vf: Called to find out how many virtual functions a device on this * bus supports. * @dma_configure: Called to setup DMA configuration on a device on * this bus. * @dma_cleanup: Called to cleanup DMA configuration on a device on * this bus. * @pm: Power management operations of this bus, callback the specific * device driver's pm-ops. * @need_parent_lock: When probing or removing a device on this bus, the * device core should lock the device's parent. * * A bus is a channel between the processor and one or more devices. For the * purposes of the device model, all devices are connected via a bus, even if * it is an internal, virtual, "platform" bus. Buses can plug into each other. * A USB controller is usually a PCI device, for example. The device model * represents the actual connections between buses and the devices they control. * A bus is represented by the bus_type structure. It contains the name, the * default attributes, the bus' methods, PM operations, and the driver core's * private data. */ struct bus_type { … }; int __must_check bus_register(const struct bus_type *bus); void bus_unregister(const struct bus_type *bus); int __must_check bus_rescan_devices(const struct bus_type *bus); struct bus_attribute { … }; #define BUS_ATTR_RW(_name) … #define BUS_ATTR_RO(_name) … #define BUS_ATTR_WO(_name) … int __must_check bus_create_file(const struct bus_type *bus, struct bus_attribute *attr); void bus_remove_file(const struct bus_type *bus, struct bus_attribute *attr); /* Matching function type for drivers/base APIs to find a specific device */ device_match_t; /* Generic device matching functions that all busses can use to match with */ int device_match_name(struct device *dev, const void *name); int device_match_of_node(struct device *dev, const void *np); int device_match_fwnode(struct device *dev, const void *fwnode); int device_match_devt(struct device *dev, const void *pdevt); int device_match_acpi_dev(struct device *dev, const void *adev); int device_match_acpi_handle(struct device *dev, const void *handle); int device_match_any(struct device *dev, const void *unused); /* iterator helpers for buses */ int bus_for_each_dev(const struct bus_type *bus, struct device *start, void *data, int (*fn)(struct device *dev, void *data)); struct device *bus_find_device(const struct bus_type *bus, struct device *start, const void *data, device_match_t match); /** * bus_find_device_by_name - device iterator for locating a particular device * of a specific name. * @bus: bus type * @start: Device to begin with * @name: name of the device to match */ static inline struct device *bus_find_device_by_name(const struct bus_type *bus, struct device *start, const char *name) { … } /** * bus_find_device_by_of_node : device iterator for locating a particular device * matching the of_node. * @bus: bus type * @np: of_node of the device to match. */ static inline struct device * bus_find_device_by_of_node(const struct bus_type *bus, const struct device_node *np) { … } /** * bus_find_device_by_fwnode : device iterator for locating a particular device * matching the fwnode. * @bus: bus type * @fwnode: fwnode of the device to match. */ static inline struct device * bus_find_device_by_fwnode(const struct bus_type *bus, const struct fwnode_handle *fwnode) { … } /** * bus_find_device_by_devt : device iterator for locating a particular device * matching the device type. * @bus: bus type * @devt: device type of the device to match. */ static inline struct device *bus_find_device_by_devt(const struct bus_type *bus, dev_t devt) { … } /** * bus_find_next_device - Find the next device after a given device in a * given bus. * @bus: bus type * @cur: device to begin the search with. */ static inline struct device * bus_find_next_device(const struct bus_type *bus,struct device *cur) { … } #ifdef CONFIG_ACPI struct acpi_device; /** * bus_find_device_by_acpi_dev : device iterator for locating a particular device * matching the ACPI COMPANION device. * @bus: bus type * @adev: ACPI COMPANION device to match. */ static inline struct device * bus_find_device_by_acpi_dev(const struct bus_type *bus, const struct acpi_device *adev) { … } #else static inline struct device * bus_find_device_by_acpi_dev(const struct bus_type *bus, const void *adev) { return NULL; } #endif int bus_for_each_drv(const struct bus_type *bus, struct device_driver *start, void *data, int (*fn)(struct device_driver *, void *)); void bus_sort_breadthfirst(const struct bus_type *bus, int (*compare)(const struct device *a, const struct device *b)); /* * Bus notifiers: Get notified of addition/removal of devices * and binding/unbinding of drivers to devices. * In the long run, it should be a replacement for the platform * notify hooks. */ struct notifier_block; int bus_register_notifier(const struct bus_type *bus, struct notifier_block *nb); int bus_unregister_notifier(const struct bus_type *bus, struct notifier_block *nb); /** * enum bus_notifier_event - Bus Notifier events that have happened * @BUS_NOTIFY_ADD_DEVICE: device is added to this bus * @BUS_NOTIFY_DEL_DEVICE: device is about to be removed from this bus * @BUS_NOTIFY_REMOVED_DEVICE: device is successfully removed from this bus * @BUS_NOTIFY_BIND_DRIVER: a driver is about to be bound to this device on this bus * @BUS_NOTIFY_BOUND_DRIVER: a driver is successfully bound to this device on this bus * @BUS_NOTIFY_UNBIND_DRIVER: a driver is about to be unbound from this device on this bus * @BUS_NOTIFY_UNBOUND_DRIVER: a driver is successfully unbound from this device on this bus * @BUS_NOTIFY_DRIVER_NOT_BOUND: a driver failed to be bound to this device on this bus * * These are the value passed to a bus notifier when a specific event happens. * * Note that bus notifiers are likely to be called with the device lock already * held by the driver core, so be careful in any notifier callback as to what * you do with the device structure. * * All bus notifiers are called with the target struct device * as an argument. */ enum bus_notifier_event { … }; struct kset *bus_get_kset(const struct bus_type *bus); struct device *bus_get_dev_root(const struct bus_type *bus); #endif
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