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
  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  */
  26 struct 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
  36 int 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
  43 void virtqueue_kick(struct virtqueue *vq);
  44
  45 bool virtqueue_kick_prepare(struct virtqueue *vq);
  46
  47 void virtqueue_notify(struct virtqueue *vq);
  48
  49 void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
  50
  51 void virtqueue_disable_cb(struct virtqueue *vq);
  52
  53 bool virtqueue_enable_cb(struct virtqueue *vq);
  54
  55 bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
  56
  57 void *virtqueue_detach_unused_buf(struct virtqueue *vq);
  58
  59 unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
  60
  61 /* FIXME: Obsolete accessor, but required for virtio_net merge. */
  62 static 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  */
  77 struct 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
  88 static inline struct virtio_device *dev_to_virtio(struct device *_dev)
  89 {
  90         return container_of(_dev, struct virtio_device, dev);
  91 }
  92
  93 int register_virtio_device(struct virtio_device *dev);
  94 void 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  */
 107 struct 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
 122 static inline struct virtio_driver *drv_to_virtio(struct device_driver *drv)
 123 {
 124         return container_of(drv, struct virtio_driver, driver);
 125 }
 126
 127 int register_virtio_driver(struct virtio_driver *drv);
 128 void 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 */