1 #ifndef _LINUX_VIRTIO_CONFIG_H
2 #define _LINUX_VIRTIO_CONFIG_H
3 /* This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
4 * anyone can use the definitions to implement compatible drivers/servers. */
6 /* Virtio devices use a standardized configuration space to define their
7 * features and pass configuration information, but each implementation can
8 * store and access that space differently. */
9 #include <linux/types.h>
11 /* Status byte for guest to report progress, and synchronize features. */
12 /* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */
13 #define VIRTIO_CONFIG_S_ACKNOWLEDGE 1
14 /* We have found a driver for the device. */
15 #define VIRTIO_CONFIG_S_DRIVER 2
16 /* Driver has used its parts of the config, and is happy */
17 #define VIRTIO_CONFIG_S_DRIVER_OK 4
18 /* We've given up on this device. */
19 #define VIRTIO_CONFIG_S_FAILED 0x80
21 /* Do we get callbacks when the ring is completely used, even if we've
23 #define VIRTIO_F_NOTIFY_ON_EMPTY 24
26 #include <linux/virtio.h>
29 * virtio_config_ops - operations for configuring a virtio device
30 * @get: read the value of a configuration field
31 * vdev: the virtio_device
32 * offset: the offset of the configuration field
33 * buf: the buffer to write the field value into.
34 * len: the length of the buffer
35 * @set: write the value of a configuration field
36 * vdev: the virtio_device
37 * offset: the offset of the configuration field
38 * buf: the buffer to read the field value from.
39 * len: the length of the buffer
40 * @get_status: read the status byte
41 * vdev: the virtio_device
42 * Returns the status byte
43 * @set_status: write the status byte
44 * vdev: the virtio_device
45 * status: the new status byte
46 * @reset: reset the device
47 * vdev: the virtio device
48 * After this, status and feature negotiation must be done again
49 * @find_vq: find a virtqueue and instantiate it.
50 * vdev: the virtio_device
51 * index: the 0-based virtqueue number in case there's more than one.
52 * callback: the virqtueue callback
53 * Returns the new virtqueue or ERR_PTR() (eg. -ENOENT).
54 * @del_vq: free a virtqueue found by find_vq().
55 * @get_features: get the array of feature bits for this device.
56 * vdev: the virtio_device
57 * Returns the first 32 feature bits (all we currently need).
58 * @set_features: confirm what device features we'll be using.
59 * vdev: the virtio_device
60 * feature: the first 32 feature bits
62 struct virtio_config_ops
64 void (*get)(struct virtio_device *vdev, unsigned offset,
65 void *buf, unsigned len);
66 void (*set)(struct virtio_device *vdev, unsigned offset,
67 const void *buf, unsigned len);
68 u8 (*get_status)(struct virtio_device *vdev);
69 void (*set_status)(struct virtio_device *vdev, u8 status);
70 void (*reset)(struct virtio_device *vdev);
71 struct virtqueue *(*find_vq)(struct virtio_device *vdev,
73 void (*callback)(struct virtqueue *));
74 void (*del_vq)(struct virtqueue *vq);
75 u32 (*get_features)(struct virtio_device *vdev);
76 void (*set_features)(struct virtio_device *vdev, u32 features);
79 /* If driver didn't advertise the feature, it will never appear. */
80 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
84 * virtio_has_feature - helper to determine if this device has this feature.
86 * @fbit: the feature bit
88 static inline bool virtio_has_feature(const struct virtio_device *vdev,
91 /* Did you forget to fix assumptions on max features? */
92 if (__builtin_constant_p(fbit))
93 BUILD_BUG_ON(fbit >= 32);
95 virtio_check_driver_offered_feature(vdev, fbit);
96 return test_bit(fbit, vdev->features);
100 * virtio_config_val - look for a feature and get a virtio config entry.
101 * @vdev: the virtio device
102 * @fbit: the feature bit
103 * @offset: the type to search for.
104 * @val: a pointer to the value to fill in.
106 * The return value is -ENOENT if the feature doesn't exist. Otherwise
107 * the config value is copied into whatever is pointed to by v. */
108 #define virtio_config_val(vdev, fbit, offset, v) \
109 virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v))
111 static inline int virtio_config_buf(struct virtio_device *vdev,
114 void *buf, unsigned len)
116 if (!virtio_has_feature(vdev, fbit))
119 vdev->config->get(vdev, offset, buf, len);
122 #endif /* __KERNEL__ */
123 #endif /* _LINUX_VIRTIO_CONFIG_H */