1 #ifndef _LINUX_VIRTIO_CONFIG_H
2 #define _LINUX_VIRTIO_CONFIG_H
3 /* Virtio devices use a standardized configuration space to define their
4 * features and pass configuration information, but each implementation can
5 * store and access that space differently. */
6 #include <linux/types.h>
8 /* Status byte for guest to report progress, and synchronize features. */
9 /* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */
10 #define VIRTIO_CONFIG_S_ACKNOWLEDGE 1
11 /* We have found a driver for the device. */
12 #define VIRTIO_CONFIG_S_DRIVER 2
13 /* Driver has used its parts of the config, and is happy */
14 #define VIRTIO_CONFIG_S_DRIVER_OK 4
15 /* We've given up on this device. */
16 #define VIRTIO_CONFIG_S_FAILED 0x80
19 #include <linux/virtio.h>
22 * virtio_config_ops - operations for configuring a virtio device
23 * @feature: search for a feature in this config
24 * vdev: the virtio_device
25 * bit: the feature bit
26 * Returns true if the feature is supported. Acknowledges the feature
27 * so the host can see it.
28 * @get: read the value of a configuration field
29 * vdev: the virtio_device
30 * offset: the offset of the configuration field
31 * buf: the buffer to write the field value into.
32 * len: the length of the buffer
33 * @set: write the value of a configuration field
34 * vdev: the virtio_device
35 * offset: the offset of the configuration field
36 * buf: the buffer to read the field value from.
37 * len: the length of the buffer
38 * @get_status: read the status byte
39 * vdev: the virtio_device
40 * Returns the status byte
41 * @set_status: write the status byte
42 * vdev: the virtio_device
43 * status: the new status byte
44 * @reset: reset the device
45 * vdev: the virtio device
46 * After this, status and feature negotiation must be done again
47 * @find_vq: find a virtqueue and instantiate it.
48 * vdev: the virtio_device
49 * index: the 0-based virtqueue number in case there's more than one.
50 * callback: the virqtueue callback
51 * Returns the new virtqueue or ERR_PTR() (eg. -ENOENT).
52 * @del_vq: free a virtqueue found by find_vq().
54 struct virtio_config_ops
56 bool (*feature)(struct virtio_device *vdev, unsigned bit);
57 void (*get)(struct virtio_device *vdev, unsigned offset,
58 void *buf, unsigned len);
59 void (*set)(struct virtio_device *vdev, unsigned offset,
60 const void *buf, unsigned len);
61 u8 (*get_status)(struct virtio_device *vdev);
62 void (*set_status)(struct virtio_device *vdev, u8 status);
63 void (*reset)(struct virtio_device *vdev);
64 struct virtqueue *(*find_vq)(struct virtio_device *vdev,
66 void (*callback)(struct virtqueue *));
67 void (*del_vq)(struct virtqueue *vq);
71 * virtio_config_val - look for a feature and get a virtio config entry.
72 * @vdev: the virtio device
73 * @fbit: the feature bit
74 * @offset: the type to search for.
75 * @val: a pointer to the value to fill in.
77 * The return value is -ENOENT if the feature doesn't exist. Otherwise
78 * the config value is copied into whatever is pointed to by v. */
79 #define virtio_config_val(vdev, fbit, offset, v) \
80 virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(v))
82 static inline int virtio_config_buf(struct virtio_device *vdev,
85 void *buf, unsigned len)
87 if (!vdev->config->feature(vdev, fbit))
90 vdev->config->get(vdev, offset, buf, len);
93 #endif /* __KERNEL__ */
94 #endif /* _LINUX_VIRTIO_CONFIG_H */