drivers/base/base.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (c) 2001-2003 Patrick Mochel <mochel@osdl.org>
 * Copyright (c) 2004-2009 Greg Kroah-Hartman <gregkh@suse.de>
 * Copyright (c) 2008-2012 Novell Inc.
 * Copyright (c) 2012-2019 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 * Copyright (c) 2012-2019 Linux Foundation
 *
 * Core driver model functions and structures that should not be
 * shared outside of the drivers/base/ directory.
 *
 */
#include <linux/notifier.h>

/**
 * struct subsys_private - structure to hold the private to the driver core portions of the bus_type/class structure.
 *
 * @subsys - the struct kset that defines this subsystem
 * @devices_kset - the subsystem's 'devices' directory
 * @interfaces - list of subsystem interfaces associated
 * @mutex - protect the devices, and interfaces lists.
 *
 * @drivers_kset - the list of drivers associated
 * @klist_devices - the klist to iterate over the @devices_kset
 * @klist_drivers - the klist to iterate over the @drivers_kset
 * @bus_notifier - the bus notifier list for anything that cares about things
 *                 on this bus.
 * @bus - pointer back to the struct bus_type that this structure is associated
 *        with.
 * @dev_root: Default device to use as the parent.
 *
 * @glue_dirs - "glue" directory to put in-between the parent device to
 *              avoid namespace conflicts
 * @class - pointer back to the struct class that this structure is associated
 *          with.
 * @lock_key:	Lock class key for use by the lock validator
 *
 * This structure is the one that is the actual kobject allowing struct
 * bus_type/class to be statically allocated safely.  Nothing outside of the
 * driver core should ever touch these fields.
 */
struct subsys_private {
	struct kset subsys;
	struct kset *devices_kset;
	struct list_head interfaces;
	struct mutex mutex;

	struct kset *drivers_kset;
	struct klist klist_devices;
	struct klist klist_drivers;
	struct blocking_notifier_head bus_notifier;
	unsigned int drivers_autoprobe:1;
	const struct bus_type *bus;
	struct device *dev_root;

	struct kset glue_dirs;
	const struct class *class;

	struct lock_class_key lock_key;
};
#define to_subsys_private(obj) container_of_const(obj, struct subsys_private, subsys.kobj)

static inline struct subsys_private *subsys_get(struct subsys_private *sp)
{
	if (sp)
		kset_get(&sp->subsys);
	return sp;
}

static inline void subsys_put(struct subsys_private *sp)
{
	if (sp)
		kset_put(&sp->subsys);
}

struct subsys_private *bus_to_subsys(const struct bus_type *bus);
struct subsys_private *class_to_subsys(const struct class *class);

struct driver_private {
	struct kobject kobj;
	struct klist klist_devices;
	struct klist_node knode_bus;
	struct module_kobject *mkobj;
	struct device_driver *driver;
};
#define to_driver(obj) container_of(obj, struct driver_private, kobj)

/**
 * struct device_private - structure to hold the private to the driver core portions of the device structure.
 *
 * @klist_children - klist containing all children of this device
 * @knode_parent - node in sibling list
 * @knode_driver - node in driver list
 * @knode_bus - node in bus list
 * @knode_class - node in class list
 * @deferred_probe - entry in deferred_probe_list which is used to retry the
 *	binding of drivers which were unable to get all the resources needed by
 *	the device; typically because it depends on another driver getting
 *	probed first.
 * @async_driver - pointer to device driver awaiting probe via async_probe
 * @device - pointer back to the struct device that this structure is
 * associated with.
 * @dead - This device is currently either in the process of or has been
 *	removed from the system. Any asynchronous events scheduled for this
 *	device should exit without taking any action.
 *
 * Nothing outside of the driver core should ever touch these fields.
 */
struct device_private {
	struct klist klist_children;
	struct klist_node knode_parent;
	struct klist_node knode_driver;
	struct klist_node knode_bus;
	struct klist_node knode_class;
	struct list_head deferred_probe;
	const struct device_driver *async_driver;
	char *deferred_probe_reason;
	struct device *device;
	u8 dead:1;
};
#define to_device_private_parent(obj)	\
	container_of(obj, struct device_private, knode_parent)
#define to_device_private_driver(obj)	\
	container_of(obj, struct device_private, knode_driver)
#define to_device_private_bus(obj)	\
	container_of(obj, struct device_private, knode_bus)
#define to_device_private_class(obj)	\
	container_of(obj, struct device_private, knode_class)

/* initialisation functions */
int devices_init(void);
int buses_init(void);
int classes_init(void);
int firmware_init(void);
#ifdef CONFIG_SYS_HYPERVISOR
int hypervisor_init(void);
#else
static inline int hypervisor_init(void) { return 0; }
#endif
int platform_bus_init(void);
int faux_bus_init(void);
void cpu_dev_init(void);
void container_dev_init(void);
#ifdef CONFIG_AUXILIARY_BUS
void auxiliary_bus_init(void);
#else
static inline void auxiliary_bus_init(void) { }
#endif

struct kobject *virtual_device_parent(void);

int bus_add_device(struct device *dev);
void bus_probe_device(struct device *dev);
void bus_remove_device(struct device *dev);
void bus_notify(struct device *dev, enum bus_notifier_event value);
bool bus_is_registered(const struct bus_type *bus);

int bus_add_driver(struct device_driver *drv);
void bus_remove_driver(struct device_driver *drv);
void device_release_driver_internal(struct device *dev, const struct device_driver *drv,
				    struct device *parent);

void driver_detach(const struct device_driver *drv);
void driver_deferred_probe_del(struct device *dev);
void device_set_deferred_probe_reason(const struct device *dev, struct va_format *vaf);
static inline int driver_match_device(const struct device_driver *drv,
				      struct device *dev)
{
	return drv->bus->match ? drv->bus->match(dev, drv) : 1;
}

static inline void dev_sync_state(struct device *dev)
{
	if (dev->bus->sync_state)
		dev->bus->sync_state(dev);
	else if (dev->driver && dev->driver->sync_state)
		dev->driver->sync_state(dev);
}

int driver_add_groups(const struct device_driver *drv, const struct attribute_group **groups);
void driver_remove_groups(const struct device_driver *drv, const struct attribute_group **groups);
void device_driver_detach(struct device *dev);

static inline void device_set_driver(struct device *dev, const struct device_driver *drv)
{
	/*
	 * Majority (all?) read accesses to dev->driver happens either
	 * while holding device lock or in bus/driver code that is only
	 * invoked when the device is bound to a driver and there is no
	 * concern of the pointer being changed while it is being read.
	 * However when reading device's uevent file we read driver pointer
	 * without taking device lock (so we do not block there for
	 * arbitrary amount of time). We use WRITE_ONCE() here to prevent
	 * tearing so that READ_ONCE() can safely be used in uevent code.
	 */
	// FIXME - this cast should not be needed "soon"
	WRITE_ONCE(dev->driver, (struct device_driver *)drv);
}

int devres_release_all(struct device *dev);
void device_block_probing(void);
void device_unblock_probing(void);
void deferred_probe_extend_timeout(void);
void driver_deferred_probe_trigger(void);
const char *device_get_devnode(const struct device *dev, umode_t *mode,
			       kuid_t *uid, kgid_t *gid, const char **tmp);

/* /sys/devices directory */
extern struct kset *devices_kset;
void devices_kset_move_last(struct device *dev);

#if defined(CONFIG_MODULES) && defined(CONFIG_SYSFS)
int module_add_driver(struct module *mod, const struct device_driver *drv);
void module_remove_driver(const struct device_driver *drv);
#else
static inline int module_add_driver(struct module *mod,
				    struct device_driver *drv)
{
	return 0;
}
static inline void module_remove_driver(struct device_driver *drv) { }
#endif

#ifdef CONFIG_DEVTMPFS
int devtmpfs_init(void);
#else
static inline int devtmpfs_init(void) { return 0; }
#endif

#ifdef CONFIG_BLOCK
extern const struct class block_class;
static inline bool is_blockdev(struct device *dev)
{
	return dev->class == &block_class;
}
#else
static inline bool is_blockdev(struct device *dev) { return false; }
#endif

/* Device links support */
int device_links_read_lock(void);
void device_links_read_unlock(int idx);
int device_links_read_lock_held(void);
int device_links_check_suppliers(struct device *dev);
void device_links_force_bind(struct device *dev);
void device_links_driver_bound(struct device *dev);
void device_links_driver_cleanup(struct device *dev);
void device_links_no_driver(struct device *dev);
bool device_links_busy(struct device *dev);
void device_links_unbind_consumers(struct device *dev);
void fw_devlink_drivers_done(void);
void fw_devlink_probing_done(void);

#define dev_for_each_link_to_supplier(__link, __dev)	\
	list_for_each_entry_srcu(__link, &(__dev)->links.suppliers, c_node, \
				 device_links_read_lock_held())

#define dev_for_each_link_to_consumer(__link, __dev)	\
	list_for_each_entry_srcu(__link, &(__dev)->links.consumers, s_node, \
				 device_links_read_lock_held())

/* device pm support */
void device_pm_move_to_tail(struct device *dev);

#ifdef CONFIG_DEVTMPFS
int devtmpfs_create_node(struct device *dev);
int devtmpfs_delete_node(struct device *dev);
#else
static inline int devtmpfs_create_node(struct device *dev) { return 0; }
static inline int devtmpfs_delete_node(struct device *dev) { return 0; }
#endif

void software_node_notify(struct device *dev);
void software_node_notify_remove(struct device *dev);