virtio.h 3.8 KB

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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. /**
  11. * virtqueue - a queue to register buffers for sending or receiving.
  12. * @callback: the function to call when buffers are consumed (can be NULL).
  13. * @vdev: the virtio device this queue was created for.
  14. * @vq_ops: the operations for this virtqueue (see below).
  15. * @priv: a pointer for the virtqueue implementation to use.
  16. */
  17. struct virtqueue
  18. {
  19. void (*callback)(struct virtqueue *vq);
  20. struct virtio_device *vdev;
  21. struct virtqueue_ops *vq_ops;
  22. void *priv;
  23. };
  24. /**
  25. * virtqueue_ops - operations for virtqueue abstraction layer
  26. * @add_buf: expose buffer to other end
  27. * vq: the struct virtqueue we're talking about.
  28. * sg: the description of the buffer(s).
  29. * out_num: the number of sg readable by other side
  30. * in_num: the number of sg which are writable (after readable ones)
  31. * data: the token identifying the buffer.
  32. * Returns 0 or an error.
  33. * @kick: update after add_buf
  34. * vq: the struct virtqueue
  35. * After one or more add_buf calls, invoke this to kick the other side.
  36. * @get_buf: get the next used buffer
  37. * vq: the struct virtqueue we're talking about.
  38. * len: the length written into the buffer
  39. * Returns NULL or the "data" token handed to add_buf.
  40. * @disable_cb: disable callbacks
  41. * vq: the struct virtqueue we're talking about.
  42. * @enable_cb: restart callbacks after disable_cb.
  43. * vq: the struct virtqueue we're talking about.
  44. * This returns "false" (and doesn't re-enable) if there are pending
  45. * buffers in the queue, to avoid a race.
  46. * @shutdown: "unadd" all buffers.
  47. * vq: the struct virtqueue we're talking about.
  48. * Remove everything from the queue.
  49. *
  50. * Locking rules are straightforward: the driver is responsible for
  51. * locking. No two operations may be invoked simultaneously.
  52. *
  53. * All operations can be called in any context.
  54. */
  55. struct virtqueue_ops {
  56. int (*add_buf)(struct virtqueue *vq,
  57. struct scatterlist sg[],
  58. unsigned int out_num,
  59. unsigned int in_num,
  60. void *data);
  61. void (*kick)(struct virtqueue *vq);
  62. void *(*get_buf)(struct virtqueue *vq, unsigned int *len);
  63. void (*disable_cb)(struct virtqueue *vq);
  64. bool (*enable_cb)(struct virtqueue *vq);
  65. void (*shutdown)(struct virtqueue *vq);
  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. * @priv: private pointer for the driver's use.
  74. */
  75. struct virtio_device
  76. {
  77. int index;
  78. struct device dev;
  79. struct virtio_device_id id;
  80. struct virtio_config_ops *config;
  81. void *priv;
  82. };
  83. int register_virtio_device(struct virtio_device *dev);
  84. void unregister_virtio_device(struct virtio_device *dev);
  85. /**
  86. * virtio_driver - operations for a virtio I/O driver
  87. * @driver: underlying device driver (populate name and owner).
  88. * @id_table: the ids serviced by this driver.
  89. * @probe: the function to call when a device is found. Returns a token for
  90. * remove, or PTR_ERR().
  91. * @remove: the function when a device is removed.
  92. * @config_changed: optional function to call when the device configuration
  93. * changes; may be called in interrupt context.
  94. */
  95. struct virtio_driver {
  96. struct device_driver driver;
  97. const struct virtio_device_id *id_table;
  98. int (*probe)(struct virtio_device *dev);
  99. void (*remove)(struct virtio_device *dev);
  100. void (*config_changed)(struct virtio_device *dev);
  101. };
  102. int register_virtio_driver(struct virtio_driver *drv);
  103. void unregister_virtio_driver(struct virtio_driver *drv);
  104. #endif /* _LINUX_VIRTIO_H */