linux/include/linux/virtio.h
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   1#ifndef _LINUX_VIRTIO_H
   2#define _LINUX_VIRTIO_H
   3/* Everything a virtio driver needs to work with any particular virtio
   4 * implementation. */
   5#include <linux/types.h>
   6#include <linux/scatterlist.h>
   7#include <linux/spinlock.h>
   8#include <linux/device.h>
   9#include <linux/mod_devicetable.h>
  10#include <linux/gfp.h>
  11
  12/**
  13 * virtqueue - a queue to register buffers for sending or receiving.
  14 * @list: the chain of virtqueues for this device
  15 * @callback: the function to call when buffers are consumed (can be NULL).
  16 * @name: the name of this virtqueue (mainly for debugging)
  17 * @vdev: the virtio device this queue was created for.
  18 * @priv: a pointer for the virtqueue implementation to use.
  19 * @index: the zero-based ordinal number for this queue.
  20 * @num_free: number of elements we expect to be able to fit.
  21 *
  22 * A note on @num_free: with indirect buffers, each buffer needs one
  23 * element in the queue, otherwise a buffer will need one element per
  24 * sg element.
  25 */
  26struct virtqueue {
  27        struct list_head list;
  28        void (*callback)(struct virtqueue *vq);
  29        const char *name;
  30        struct virtio_device *vdev;
  31        unsigned int index;
  32        unsigned int num_free;
  33        void *priv;
  34};
  35
  36int virtqueue_add_buf(struct virtqueue *vq,
  37                      struct scatterlist sg[],
  38                      unsigned int out_num,
  39                      unsigned int in_num,
  40                      void *data,
  41                      gfp_t gfp);
  42
  43void virtqueue_kick(struct virtqueue *vq);
  44
  45bool virtqueue_kick_prepare(struct virtqueue *vq);
  46
  47void virtqueue_notify(struct virtqueue *vq);
  48
  49void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
  50
  51void virtqueue_disable_cb(struct virtqueue *vq);
  52
  53bool virtqueue_enable_cb(struct virtqueue *vq);
  54
  55bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
  56
  57void *virtqueue_detach_unused_buf(struct virtqueue *vq);
  58
  59unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
  60
  61/* FIXME: Obsolete accessor, but required for virtio_net merge. */
  62static inline unsigned int virtqueue_get_queue_index(struct virtqueue *vq)
  63{
  64        return vq->index;
  65}
  66
  67/**
  68 * virtio_device - representation of a device using virtio
  69 * @index: unique position on the virtio bus
  70 * @dev: underlying device.
  71 * @id: the device type identification (used to match it with a driver).
  72 * @config: the configuration ops for this device.
  73 * @vqs: the list of virtqueues for this device.
  74 * @features: the features supported by both driver and device.
  75 * @priv: private pointer for the driver's use.
  76 */
  77struct virtio_device {
  78        int index;
  79        struct device dev;
  80        struct virtio_device_id id;
  81        const struct virtio_config_ops *config;
  82        struct list_head vqs;
  83        /* Note that this is a Linux set_bit-style bitmap. */
  84        unsigned long features[1];
  85        void *priv;
  86};
  87
  88static inline struct virtio_device *dev_to_virtio(struct device *_dev)
  89{
  90        return container_of(_dev, struct virtio_device, dev);
  91}
  92
  93int register_virtio_device(struct virtio_device *dev);
  94void unregister_virtio_device(struct virtio_device *dev);
  95
  96/**
  97 * virtio_driver - operations for a virtio I/O driver
  98 * @driver: underlying device driver (populate name and owner).
  99 * @id_table: the ids serviced by this driver.
 100 * @feature_table: an array of feature numbers supported by this driver.
 101 * @feature_table_size: number of entries in the feature table array.
 102 * @probe: the function to call when a device is found.  Returns 0 or -errno.
 103 * @remove: the function to call when a device is removed.
 104 * @config_changed: optional function to call when the device configuration
 105 *    changes; may be called in interrupt context.
 106 */
 107struct virtio_driver {
 108        struct device_driver driver;
 109        const struct virtio_device_id *id_table;
 110        const unsigned int *feature_table;
 111        unsigned int feature_table_size;
 112        int (*probe)(struct virtio_device *dev);
 113        void (*scan)(struct virtio_device *dev);
 114        void (*remove)(struct virtio_device *dev);
 115        void (*config_changed)(struct virtio_device *dev);
 116#ifdef CONFIG_PM
 117        int (*freeze)(struct virtio_device *dev);
 118        int (*restore)(struct virtio_device *dev);
 119#endif
 120};
 121
 122static inline struct virtio_driver *drv_to_virtio(struct device_driver *drv)
 123{
 124        return container_of(drv, struct virtio_driver, driver);
 125}
 126
 127int register_virtio_driver(struct virtio_driver *drv);
 128void unregister_virtio_driver(struct virtio_driver *drv);
 129
 130/* module_virtio_driver() - Helper macro for drivers that don't do
 131 * anything special in module init/exit.  This eliminates a lot of
 132 * boilerplate.  Each module may only use this macro once, and
 133 * calling it replaces module_init() and module_exit()
 134 */
 135#define module_virtio_driver(__virtio_driver) \
 136        module_driver(__virtio_driver, register_virtio_driver, \
 137                        unregister_virtio_driver)
 138#endif /* _LINUX_VIRTIO_H */
 139
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