include/linux/virtio.h

   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 #include <linux/vringh.h>
  12
  13 /**
  14  * virtqueue - a queue to register buffers for sending or receiving.
  15  * @list: the chain of virtqueues for this device
  16  * @callback: the function to call when buffers are consumed (can be NULL).
  17  * @name: the name of this virtqueue (mainly for debugging)
  18  * @vdev: the virtio device this queue was created for.
  19  * @priv: a pointer for the virtqueue implementation to use.
  20  * @index: the zero-based ordinal number for this queue.
  21  * @num_free: number of elements we expect to be able to fit.
  22  *
  23  * A note on @num_free: with indirect buffers, each buffer needs one
  24  * element in the queue, otherwise a buffer will need one element per
  25  * sg element.
  26  */
  27 struct virtqueue {
  28         struct list_head list;
  29         void (*callback)(struct virtqueue *vq);
  30         const char *name;
  31         struct virtio_device *vdev;
  32         unsigned int index;
  33         unsigned int num_free;
  34         void *priv;
  35 };
  36
  37 int virtqueue_add_buf(struct virtqueue *vq,
  38                       struct scatterlist sg[],
  39                       unsigned int out_num,
  40                       unsigned int in_num,
  41                       void *data,
  42                       gfp_t gfp);
  43
  44 int virtqueue_add_outbuf(struct virtqueue *vq,
  45                          struct scatterlist sg[], unsigned int num,
  46                          void *data,
  47                          gfp_t gfp);
  48
  49 int virtqueue_add_inbuf(struct virtqueue *vq,
  50                         struct scatterlist sg[], unsigned int num,
  51                         void *data,
  52                         gfp_t gfp);
  53
  54 int virtqueue_add_sgs(struct virtqueue *vq,
  55                       struct scatterlist *sgs[],
  56                       unsigned int out_sgs,
  57                       unsigned int in_sgs,
  58                       void *data,
  59                       gfp_t gfp);
  60
  61 void virtqueue_kick(struct virtqueue *vq);
  62
  63 bool virtqueue_kick_prepare(struct virtqueue *vq);
  64
  65 void virtqueue_notify(struct virtqueue *vq);
  66
  67 void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
  68
  69 void virtqueue_disable_cb(struct virtqueue *vq);
  70
  71 bool virtqueue_enable_cb(struct virtqueue *vq);
  72
  73 unsigned virtqueue_enable_cb_prepare(struct virtqueue *vq);
  74
  75 bool virtqueue_poll(struct virtqueue *vq, unsigned);
  76
  77 bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
  78
  79 void *virtqueue_detach_unused_buf(struct virtqueue *vq);
  80
  81 unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
  82
  83 /**
  84  * virtio_device - representation of a device using virtio
  85  * @index: unique position on the virtio bus
  86  * @dev: underlying device.
  87  * @id: the device type identification (used to match it with a driver).
  88  * @config: the configuration ops for this device.
  89  * @vringh_config: configuration ops for host vrings.
  90  * @vqs: the list of virtqueues for this device.
  91  * @features: the features supported by both driver and device.
  92  * @priv: private pointer for the driver's use.
  93  */
  94 struct virtio_device {
  95         int index;
  96         struct device dev;
  97         struct virtio_device_id id;
  98         const struct virtio_config_ops *config;
  99         const struct vringh_config_ops *vringh_config;
 100         struct list_head vqs;
 101         /* Note that this is a Linux set_bit-style bitmap. */
 102         unsigned long features[1];
 103         void *priv;
 104 };
 105
 106 static inline struct virtio_device *dev_to_virtio(struct device *_dev)
 107 {
 108         return container_of(_dev, struct virtio_device, dev);
 109 }
 110
 111 int register_virtio_device(struct virtio_device *dev);
 112 void unregister_virtio_device(struct virtio_device *dev);
 113
 114 /**
 115  * virtio_driver - operations for a virtio I/O driver
 116  * @driver: underlying device driver (populate name and owner).
 117  * @id_table: the ids serviced by this driver.
 118  * @feature_table: an array of feature numbers supported by this driver.
 119  * @feature_table_size: number of entries in the feature table array.
 120  * @probe: the function to call when a device is found.  Returns 0 or -errno.
 121  * @remove: the function to call when a device is removed.
 122  * @config_changed: optional function to call when the device configuration
 123  *    changes; may be called in interrupt context.
 124  */
 125 struct virtio_driver {
 126         struct device_driver driver;
 127         const struct virtio_device_id *id_table;
 128         const unsigned int *feature_table;
 129         unsigned int feature_table_size;
 130         int (*probe)(struct virtio_device *dev);
 131         void (*scan)(struct virtio_device *dev);
 132         void (*remove)(struct virtio_device *dev);
 133         void (*config_changed)(struct virtio_device *dev);
 134 #ifdef CONFIG_PM
 135         int (*freeze)(struct virtio_device *dev);
 136         int (*restore)(struct virtio_device *dev);
 137 #endif
 138 };
 139
 140 static inline struct virtio_driver *drv_to_virtio(struct device_driver *drv)
 141 {
 142         return container_of(drv, struct virtio_driver, driver);
 143 }
 144
 145 int register_virtio_driver(struct virtio_driver *drv);
 146 void unregister_virtio_driver(struct virtio_driver *drv);
 147
 148 /* module_virtio_driver() - Helper macro for drivers that don't do
 149  * anything special in module init/exit.  This eliminates a lot of
 150  * boilerplate.  Each module may only use this macro once, and
 151  * calling it replaces module_init() and module_exit()
 152  */
 153 #define module_virtio_driver(__virtio_driver) \
 154         module_driver(__virtio_driver, register_virtio_driver, \
 155                         unregister_virtio_driver)
 156 #endif /* _LINUX_VIRTIO_H */