include/linux/mdev.h

   1 /*
   2  * Mediated device definition
   3  *
   4  * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
   5  *     Author: Neo Jia <cjia@nvidia.com>
   6  *             Kirti Wankhede <kwankhede@nvidia.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #ifndef MDEV_H
  14 #define MDEV_H
  15
  16 /* Parent device */
  17 struct parent_device {
  18         struct device           *dev;
  19         const struct parent_ops *ops;
  20
  21         /* internal */
  22         struct kref             ref;
  23         struct mutex            lock;
  24         struct list_head        next;
  25         struct kset             *mdev_types_kset;
  26         struct list_head        type_list;
  27 };
  28
  29 /* Mediated device */
  30 struct mdev_device {
  31         struct device           dev;
  32         struct parent_device    *parent;
  33         uuid_le                 uuid;
  34         void                    *driver_data;
  35
  36         /* internal */
  37         struct kref             ref;
  38         struct list_head        next;
  39         struct kobject          *type_kobj;
  40 };
  41
  42 /**
  43  * struct parent_ops - Structure to be registered for each parent device to
  44  * register the device to mdev module.
  45  *
  46  * @owner:              The module owner.
  47  * @dev_attr_groups:    Attributes of the parent device.
  48  * @mdev_attr_groups:   Attributes of the mediated device.
  49  * @supported_type_groups: Attributes to define supported types. It is mandatory
  50  *                      to provide supported types.
  51  * @create:             Called to allocate basic resources in parent device's
  52  *                      driver for a particular mediated device. It is
  53  *                      mandatory to provide create ops.
  54  *                      @kobj: kobject of type for which 'create' is called.
  55  *                      @mdev: mdev_device structure on of mediated device
  56  *                            that is being created
  57  *                      Returns integer: success (0) or error (< 0)
  58  * @remove:             Called to free resources in parent device's driver for a
  59  *                      a mediated device. It is mandatory to provide 'remove'
  60  *                      ops.
  61  *                      @mdev: mdev_device device structure which is being
  62  *                             destroyed
  63  *                      Returns integer: success (0) or error (< 0)
  64  * @open:               Open mediated device.
  65  *                      @mdev: mediated device.
  66  *                      Returns integer: success (0) or error (< 0)
  67  * @release:            release mediated device
  68  *                      @mdev: mediated device.
  69  * @read:               Read emulation callback
  70  *                      @mdev: mediated device structure
  71  *                      @buf: read buffer
  72  *                      @count: number of bytes to read
  73  *                      @ppos: address.
  74  *                      Retuns number on bytes read on success or error.
  75  * @write:              Write emulation callback
  76  *                      @mdev: mediated device structure
  77  *                      @buf: write buffer
  78  *                      @count: number of bytes to be written
  79  *                      @ppos: address.
  80  *                      Retuns number on bytes written on success or error.
  81  * @ioctl:              IOCTL callback
  82  *                      @mdev: mediated device structure
  83  *                      @cmd: ioctl command
  84  *                      @arg: arguments to ioctl
  85  * @mmap:               mmap callback
  86  *                      @mdev: mediated device structure
  87  *                      @vma: vma structure
  88  * Parent device that support mediated device should be registered with mdev
  89  * module with parent_ops structure.
  90  **/
  91
  92 struct parent_ops {
  93         struct module   *owner;
  94         const struct attribute_group **dev_attr_groups;
  95         const struct attribute_group **mdev_attr_groups;
  96         struct attribute_group **supported_type_groups;
  97
  98         int     (*create)(struct kobject *kobj, struct mdev_device *mdev);
  99         int     (*remove)(struct mdev_device *mdev);
 100         int     (*open)(struct mdev_device *mdev);
 101         void    (*release)(struct mdev_device *mdev);
 102         ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
 103                         size_t count, loff_t *ppos);
 104         ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
 105                          size_t count, loff_t *ppos);
 106         ssize_t (*ioctl)(struct mdev_device *mdev, unsigned int cmd,
 107                          unsigned long arg);
 108         int     (*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma);
 109 };
 110
 111 /* interface for exporting mdev supported type attributes */
 112 struct mdev_type_attribute {
 113         struct attribute attr;
 114         ssize_t (*show)(struct kobject *kobj, struct device *dev, char *buf);
 115         ssize_t (*store)(struct kobject *kobj, struct device *dev,
 116                          const char *buf, size_t count);
 117 };
 118
 119 #define MDEV_TYPE_ATTR(_name, _mode, _show, _store)             \
 120 struct mdev_type_attribute mdev_type_attr_##_name =             \
 121         __ATTR(_name, _mode, _show, _store)
 122 #define MDEV_TYPE_ATTR_RW(_name) \
 123         struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RW(_name)
 124 #define MDEV_TYPE_ATTR_RO(_name) \
 125         struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RO(_name)
 126 #define MDEV_TYPE_ATTR_WO(_name) \
 127         struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_WO(_name)
 128
 129 /**
 130  * struct mdev_driver - Mediated device driver
 131  * @name: driver name
 132  * @probe: called when new device created
 133  * @remove: called when device removed
 134  * @driver: device driver structure
 135  *
 136  **/
 137 struct mdev_driver {
 138         const char *name;
 139         int  (*probe)(struct device *dev);
 140         void (*remove)(struct device *dev);
 141         struct device_driver driver;
 142 };
 143
 144 #define to_mdev_driver(drv)     container_of(drv, struct mdev_driver, driver)
 145 #define to_mdev_device(dev)     container_of(dev, struct mdev_device, dev)
 146
 147 static inline void *mdev_get_drvdata(struct mdev_device *mdev)
 148 {
 149         return mdev->driver_data;
 150 }
 151
 152 static inline void mdev_set_drvdata(struct mdev_device *mdev, void *data)
 153 {
 154         mdev->driver_data = data;
 155 }
 156
 157 extern struct bus_type mdev_bus_type;
 158
 159 #define dev_is_mdev(d) ((d)->bus == &mdev_bus_type)
 160
 161 extern int  mdev_register_device(struct device *dev,
 162                                  const struct parent_ops *ops);
 163 extern void mdev_unregister_device(struct device *dev);
 164
 165 extern int  mdev_register_driver(struct mdev_driver *drv, struct module *owner);
 166 extern void mdev_unregister_driver(struct mdev_driver *drv);
 167
 168 #endif /* MDEV_H */