// SPDX-License-Identifier: GPL-2.0
/*
 * bus.h - the bus-specific portions of the driver model
 *
 * Copyright (c) 2001-2003 Patrick Mochel <mochel@osdl.org>
 * Copyright (c) 2004-2009 Greg Kroah-Hartman <gregkh@suse.de>
 * Copyright (c) 2008-2009 Novell Inc.
 * Copyright (c) 2012-2019 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 * 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).
 * @dev_root:   Default device to use as the parent.
 * @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.
 * @pm:         Power management operations of this bus, callback the specific
 *              device driver's pm-ops.
 * @iommu_ops:  IOMMU specific operations for this bus, used to attach IOMMU
 *              driver implementations to a bus and allow the driver to do
 *              bus-specific setup
 * @p:          The private data of the driver core, only the driver core can
 *              touch this.
 * @lock_key:   Lock class key for use by the lock validator
 * @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 {
        const char              *name;
        const char              *dev_name;
        struct device           *dev_root;
        const struct attribute_group **bus_groups;
        const struct attribute_group **dev_groups;
        const struct attribute_group **drv_groups;

        int (*match)(struct device *dev, struct device_driver *drv);
        int (*uevent)(struct device *dev, struct kobj_uevent_env *env);
        int (*probe)(struct device *dev);
        void (*sync_state)(struct device *dev);
        void (*remove)(struct device *dev);
        void (*shutdown)(struct device *dev);

        int (*online)(struct device *dev);
        int (*offline)(struct device *dev);

        int (*suspend)(struct device *dev, pm_message_t state);
        int (*resume)(struct device *dev);

        int (*num_vf)(struct device *dev);

        int (*dma_configure)(struct device *dev);

        const struct dev_pm_ops *pm;

        const struct iommu_ops *iommu_ops;

        struct subsys_private *p;
        struct lock_class_key lock_key;

        bool need_parent_lock;
};

extern int __must_check bus_register(struct bus_type *bus);

extern void bus_unregister(struct bus_type *bus);

extern int __must_check bus_rescan_devices(struct bus_type *bus);

struct bus_attribute {
        struct attribute        attr;
        ssize_t (*show)(struct bus_type *bus, char *buf);
        ssize_t (*store)(struct bus_type *bus, const char *buf, size_t count);
};

#define BUS_ATTR_RW(_name) \
        struct bus_attribute bus_attr_##_name = __ATTR_RW(_name)
#define BUS_ATTR_RO(_name) \
        struct bus_attribute bus_attr_##_name = __ATTR_RO(_name)
#define BUS_ATTR_WO(_name) \
        struct bus_attribute bus_attr_##_name = __ATTR_WO(_name)

extern int __must_check bus_create_file(struct bus_type *,
                                        struct bus_attribute *);
extern void bus_remove_file(struct bus_type *, struct bus_attribute *);

/* 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_any(struct device *dev, const void *unused);

/* iterator helpers for buses */
struct subsys_dev_iter {
        struct klist_iter               ki;
        const struct device_type        *type;
};
void subsys_dev_iter_init(struct subsys_dev_iter *iter,
                         struct bus_type *subsys,
                         struct device *start,
                         const struct device_type *type);
struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter);
void subsys_dev_iter_exit(struct subsys_dev_iter *iter);

int bus_for_each_dev(struct bus_type *bus, struct device *start, void *data,
                     int (*fn)(struct device *dev, void *data));
struct device *bus_find_device(struct bus_type *bus, struct device *start,
                               const void *data,
                               int (*match)(struct device *dev, const void *data));
/**
 * 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(struct bus_type *bus,
                                                     struct device *start,
                                                     const char *name)
{
        return bus_find_device(bus, start, name, device_match_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(struct bus_type *bus, const struct device_node *np)
{
        return bus_find_device(bus, NULL, np, device_match_of_node);
}

/**
 * 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(struct bus_type *bus, const struct fwnode_handle *fwnode)
{
        return bus_find_device(bus, NULL, fwnode, device_match_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(struct bus_type *bus,
                                                     dev_t devt)
{
        return bus_find_device(bus, NULL, &devt, device_match_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(struct bus_type *bus,struct device *cur)
{
        return bus_find_device(bus, cur, NULL, device_match_any);
}

#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(struct bus_type *bus, const struct acpi_device *adev)
{
        return bus_find_device(bus, NULL, adev, device_match_acpi_dev);
}
#else
static inline struct device *
bus_find_device_by_acpi_dev(struct bus_type *bus, const void *adev)
{
        return NULL;
}
#endif

struct device *subsys_find_device_by_id(struct bus_type *bus, unsigned int id,
                                        struct device *hint);
int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
                     void *data, int (*fn)(struct device_driver *, void *));
void bus_sort_breadthfirst(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;

extern int bus_register_notifier(struct bus_type *bus,
                                 struct notifier_block *nb);
extern int bus_unregister_notifier(struct bus_type *bus,
                                   struct notifier_block *nb);

/* All 4 notifers below get called with the target struct device *
 * as an argument. Note that those functions are likely to be called
 * with the device lock held in the core, so be careful.
 */
#define BUS_NOTIFY_ADD_DEVICE           0x00000001 /* device added */
#define BUS_NOTIFY_DEL_DEVICE           0x00000002 /* device to be removed */
#define BUS_NOTIFY_REMOVED_DEVICE       0x00000003 /* device removed */
#define BUS_NOTIFY_BIND_DRIVER          0x00000004 /* driver about to be
                                                      bound */
#define BUS_NOTIFY_BOUND_DRIVER         0x00000005 /* driver bound to device */
#define BUS_NOTIFY_UNBIND_DRIVER        0x00000006 /* driver about to be
                                                      unbound */
#define BUS_NOTIFY_UNBOUND_DRIVER       0x00000007 /* driver is unbound
                                                      from the device */
#define BUS_NOTIFY_DRIVER_NOT_BOUND     0x00000008 /* driver fails to be bound */

extern struct kset *bus_get_kset(struct bus_type *bus);
extern struct klist *bus_get_device_klist(struct bus_type *bus);

#endif