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 * @get: read the value of a configuration field
24 * vdev: the virtio_device
25 * offset: the offset of the configuration field
26 * buf: the buffer to write the field value into.
27 * len: the length of the buffer
28 * @set: write the value of a configuration field
29 * vdev: the virtio_device
30 * offset: the offset of the configuration field
31 * buf: the buffer to read the field value from.
32 * len: the length of the buffer
33 * @get_status: read the status byte
34 * vdev: the virtio_device
35 * Returns the status byte
36 * @set_status: write the status byte
37 * vdev: the virtio_device
38 * status: the new status byte
39 * @reset: reset the device
40 * vdev: the virtio device
41 * After this, status and feature negotiation must be done again
42 * @find_vq: find a virtqueue and instantiate it.
43 * vdev: the virtio_device
44 * index: the 0-based virtqueue number in case there's more than one.
45 * callback: the virqtueue callback
46 * Returns the new virtqueue or ERR_PTR() (eg. -ENOENT).
47 * @del_vq: free a virtqueue found by find_vq().
48 * @get_features: get the array of feature bits for this device.
49 * vdev: the virtio_device
50 * Returns the first 32 feature bits (all we currently need).
51 * @set_features: confirm what device features we'll be using.
52 * vdev: the virtio_device
53 * feature: the first 32 feature bits
55 struct virtio_config_ops
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
);
68 u32 (*get_features
)(struct virtio_device
*vdev
);
69 void (*set_features
)(struct virtio_device
*vdev
, u32 features
);
72 /* If driver didn't advertise the feature, it will never appear. */
73 void virtio_check_driver_offered_feature(const struct virtio_device
*vdev
,
77 * virtio_has_feature - helper to determine if this device has this feature.
79 * @fbit: the feature bit
81 static inline bool virtio_has_feature(const struct virtio_device
*vdev
,
84 /* Did you forget to fix assumptions on max features? */
85 if (__builtin_constant_p(fbit
))
86 BUILD_BUG_ON(fbit
>= 32);
88 virtio_check_driver_offered_feature(vdev
, fbit
);
89 return test_bit(fbit
, vdev
->features
);
93 * virtio_config_val - look for a feature and get a virtio config entry.
94 * @vdev: the virtio device
95 * @fbit: the feature bit
96 * @offset: the type to search for.
97 * @val: a pointer to the value to fill in.
99 * The return value is -ENOENT if the feature doesn't exist. Otherwise
100 * the config value is copied into whatever is pointed to by v. */
101 #define virtio_config_val(vdev, fbit, offset, v) \
102 virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(v))
104 static inline int virtio_config_buf(struct virtio_device
*vdev
,
107 void *buf
, unsigned len
)
109 if (!virtio_has_feature(vdev
, fbit
))
112 vdev
->config
->get(vdev
, offset
, buf
, len
);
115 #endif /* __KERNEL__ */
116 #endif /* _LINUX_VIRTIO_CONFIG_H */