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/* SPDX-License-Identifier: GPL-2.0-only */
* Mediated device definition
* Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
* Author: Neo Jia <>
* Kirti Wankhede <>
#ifndef MDEV_H
#define MDEV_H
struct mdev_type;
struct mdev_device {
struct device dev;
guid_t uuid;
void *driver_data;
struct list_head next;
struct mdev_type *type;
bool active;
static inline struct mdev_device *to_mdev_device(struct device *dev)
return container_of(dev, struct mdev_device, dev);
unsigned int mdev_get_type_group_id(struct mdev_device *mdev);
unsigned int mtype_get_type_group_id(struct mdev_type *mtype);
struct device *mtype_get_parent_dev(struct mdev_type *mtype);
* struct mdev_parent_ops - Structure to be registered for each parent device to
* register the device to mdev module.
* @owner: The module owner.
* @device_driver: Which device driver to probe() on newly created devices
* @dev_attr_groups: Attributes of the parent device.
* @mdev_attr_groups: Attributes of the mediated device.
* @supported_type_groups: Attributes to define supported types. It is mandatory
* to provide supported types.
* @create: Called to allocate basic resources in parent device's
* driver for a particular mediated device. It is
* mandatory to provide create ops.
* @mdev: mdev_device structure on of mediated device
* that is being created
* Returns integer: success (0) or error (< 0)
* @remove: Called to free resources in parent device's driver for
* a mediated device. It is mandatory to provide 'remove'
* ops.
* @mdev: mdev_device device structure which is being
* destroyed
* Returns integer: success (0) or error (< 0)
* @read: Read emulation callback
* @mdev: mediated device structure
* @buf: read buffer
* @count: number of bytes to read
* @ppos: address.
* Retuns number on bytes read on success or error.
* @write: Write emulation callback
* @mdev: mediated device structure
* @buf: write buffer
* @count: number of bytes to be written
* @ppos: address.
* Retuns number on bytes written on success or error.
* @ioctl: IOCTL callback
* @mdev: mediated device structure
* @cmd: ioctl command
* @arg: arguments to ioctl
* @mmap: mmap callback
* @mdev: mediated device structure
* @vma: vma structure
* @request: request callback to release device
* @mdev: mediated device structure
* @count: request sequence number
* Parent device that support mediated device should be registered with mdev
* module with mdev_parent_ops structure.
struct mdev_parent_ops {
struct module *owner;
struct mdev_driver *device_driver;
const struct attribute_group **dev_attr_groups;
const struct attribute_group **mdev_attr_groups;
struct attribute_group **supported_type_groups;
int (*create)(struct mdev_device *mdev);
int (*remove)(struct mdev_device *mdev);
int (*open_device)(struct mdev_device *mdev);
void (*close_device)(struct mdev_device *mdev);
ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
size_t count, loff_t *ppos);
ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
size_t count, loff_t *ppos);
long (*ioctl)(struct mdev_device *mdev, unsigned int cmd,
unsigned long arg);
int (*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma);
void (*request)(struct mdev_device *mdev, unsigned int count);
/* interface for exporting mdev supported type attributes */
struct mdev_type_attribute {
struct attribute attr;
ssize_t (*show)(struct mdev_type *mtype,
struct mdev_type_attribute *attr, char *buf);
ssize_t (*store)(struct mdev_type *mtype,
struct mdev_type_attribute *attr, const char *buf,
size_t count);
#define MDEV_TYPE_ATTR(_name, _mode, _show, _store) \
struct mdev_type_attribute mdev_type_attr_##_name = \
__ATTR(_name, _mode, _show, _store)
#define MDEV_TYPE_ATTR_RW(_name) \
struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RW(_name)
#define MDEV_TYPE_ATTR_RO(_name) \
struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RO(_name)
#define MDEV_TYPE_ATTR_WO(_name) \
struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_WO(_name)
* struct mdev_driver - Mediated device driver
* @probe: called when new device created
* @remove: called when device removed
* @driver: device driver structure
struct mdev_driver {
int (*probe)(struct mdev_device *dev);
void (*remove)(struct mdev_device *dev);
struct device_driver driver;
static inline void *mdev_get_drvdata(struct mdev_device *mdev)
return mdev->driver_data;
static inline void mdev_set_drvdata(struct mdev_device *mdev, void *data)
mdev->driver_data = data;
static inline const guid_t *mdev_uuid(struct mdev_device *mdev)
return &mdev->uuid;
extern struct bus_type mdev_bus_type;
int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops);
void mdev_unregister_device(struct device *dev);
int mdev_register_driver(struct mdev_driver *drv);
void mdev_unregister_driver(struct mdev_driver *drv);
struct device *mdev_parent_dev(struct mdev_device *mdev);
static inline struct device *mdev_dev(struct mdev_device *mdev)
return &mdev->dev;
static inline struct mdev_device *mdev_from_dev(struct device *dev)
return dev->bus == &mdev_bus_type ? to_mdev_device(dev) : NULL;
#endif /* MDEV_H */