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_outbuf(struct virtqueue *vq,
  38                          struct scatterlist sg[], unsigned int num,
  39                          void *data,
  40                          gfp_t gfp);
  41
  42 int virtqueue_add_inbuf(struct virtqueue *vq,
  43                         struct scatterlist sg[], unsigned int num,
  44                         void *data,
  45                         gfp_t gfp);
  46
  47 int virtqueue_add_sgs(struct virtqueue *vq,
  48                       struct scatterlist *sgs[],
  49                       unsigned int out_sgs,
  50                       unsigned int in_sgs,
  51                       void *data,
  52                       gfp_t gfp);
  53
  54 void virtqueue_kick(struct virtqueue *vq);
  55
  56 bool virtqueue_kick_prepare(struct virtqueue *vq);
  57
  58 void virtqueue_notify(struct virtqueue *vq);
  59
  60 void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
  61
  62 void virtqueue_disable_cb(struct virtqueue *vq);
  63
  64 bool virtqueue_enable_cb(struct virtqueue *vq);
  65
  66 bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
  67
  68 void *virtqueue_detach_unused_buf(struct virtqueue *vq);
  69
  70 unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
  71
  72 /**
  73  * virtio_device - representation of a device using virtio
  74  * @index: unique position on the virtio bus
  75  * @dev: underlying device.
  76  * @id: the device type identification (used to match it with a driver).
  77  * @config: the configuration ops for this device.
  78  * @vringh_config: configuration ops for host vrings.
  79  * @vqs: the list of virtqueues for this device.
  80  * @features: the features supported by both driver and device.
  81  * @priv: private pointer for the driver's use.
  82  */
  83 struct virtio_device {
  84         int index;
  85         struct device dev;
  86         struct virtio_device_id id;
  87         const struct virtio_config_ops *config;
  88         const struct vringh_config_ops *vringh_config;
  89         struct list_head vqs;
  90         /* Note that this is a Linux set_bit-style bitmap. */
  91         unsigned long features[1];
  92         void *priv;
  93 };
  94
  95 static inline struct virtio_device *dev_to_virtio(struct device *_dev)
  96 {
  97         return container_of(_dev, struct virtio_device, dev);
  98 }
  99
 100 int register_virtio_device(struct virtio_device *dev);
 101 void unregister_virtio_device(struct virtio_device *dev);
 102
 103 /**
 104  * virtio_driver - operations for a virtio I/O driver
 105  * @driver: underlying device driver (populate name and owner).
 106  * @id_table: the ids serviced by this driver.
 107  * @feature_table: an array of feature numbers supported by this driver.
 108  * @feature_table_size: number of entries in the feature table array.
 109  * @probe: the function to call when a device is found.  Returns 0 or -errno.
 110  * @remove: the function to call when a device is removed.
 111  * @config_changed: optional function to call when the device configuration
 112  *    changes; may be called in interrupt context.
 113  */
 114 struct virtio_driver {
 115         struct device_driver driver;
 116         const struct virtio_device_id *id_table;
 117         const unsigned int *feature_table;
 118         unsigned int feature_table_size;
 119         int (*probe)(struct virtio_device *dev);
 120         void (*scan)(struct virtio_device *dev);
 121         void (*remove)(struct virtio_device *dev);
 122         void (*config_changed)(struct virtio_device *dev);
 123 #ifdef CONFIG_PM
 124         int (*freeze)(struct virtio_device *dev);
 125         int (*restore)(struct virtio_device *dev);
 126 #endif
 127 };
 128
 129 static inline struct virtio_driver *drv_to_virtio(struct device_driver *drv)
 130 {
 131         return container_of(drv, struct virtio_driver, driver);
 132 }
 133
 134 int register_virtio_driver(struct virtio_driver *drv);
 135 void unregister_virtio_driver(struct virtio_driver *drv);
 136
 137 /* module_virtio_driver() - Helper macro for drivers that don't do
 138  * anything special in module init/exit.  This eliminates a lot of
 139  * boilerplate.  Each module may only use this macro once, and
 140  * calling it replaces module_init() and module_exit()
 141  */
 142 #define module_virtio_driver(__virtio_driver) \
 143         module_driver(__virtio_driver, register_virtio_driver, \
 144                         unregister_virtio_driver)
 145 #endif /* _LINUX_VIRTIO_H */