Linux kernel mirror (for testing)
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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>
7
8/* Status byte for guest to report progress, and synchronize config. */
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
17
18/* Feature byte (actually 7 bits availabe): */
19/* Requirements/features of the virtio implementation. */
20#define VIRTIO_CONFIG_F_VIRTIO 1
21/* Requirements/features of the virtqueue (may have more than one). */
22#define VIRTIO_CONFIG_F_VIRTQUEUE 2
23
24#ifdef __KERNEL__
25struct virtio_device;
26
27/**
28 * virtio_config_ops - operations for configuring a virtio device
29 * @find: search for the next configuration field of the given type.
30 * vdev: the virtio_device
31 * type: the feature type
32 * len: the (returned) length of the field if found.
33 * Returns a token if found, or NULL. Never returnes the same field twice
34 * (ie. it's used up).
35 * @get: read the value of a configuration field after find().
36 * vdev: the virtio_device
37 * token: the token returned from find().
38 * buf: the buffer to write the field value into.
39 * len: the length of the buffer (given by find()).
40 * Note that contents are conventionally little-endian.
41 * @set: write the value of a configuration field after find().
42 * vdev: the virtio_device
43 * token: the token returned from find().
44 * buf: the buffer to read the field value from.
45 * len: the length of the buffer (given by find()).
46 * Note that contents are conventionally little-endian.
47 * @get_status: read the status byte
48 * vdev: the virtio_device
49 * Returns the status byte
50 * @set_status: write the status byte
51 * vdev: the virtio_device
52 * status: the new status byte
53 * @find_vq: find the first VIRTIO_CONFIG_F_VIRTQUEUE and create a virtqueue.
54 * vdev: the virtio_device
55 * callback: the virqtueue callback
56 * Returns the new virtqueue or ERR_PTR().
57 * @del_vq: free a virtqueue found by find_vq().
58 */
59struct virtio_config_ops
60{
61 void *(*find)(struct virtio_device *vdev, u8 type, unsigned *len);
62 void (*get)(struct virtio_device *vdev, void *token,
63 void *buf, unsigned len);
64 void (*set)(struct virtio_device *vdev, void *token,
65 const void *buf, unsigned len);
66 u8 (*get_status)(struct virtio_device *vdev);
67 void (*set_status)(struct virtio_device *vdev, u8 status);
68 struct virtqueue *(*find_vq)(struct virtio_device *vdev,
69 bool (*callback)(struct virtqueue *));
70 void (*del_vq)(struct virtqueue *vq);
71};
72
73/**
74 * virtio_config_val - get a single virtio config and mark it used.
75 * @config: the virtio config space
76 * @type: the type to search for.
77 * @val: a pointer to the value to fill in.
78 *
79 * Once used, the config type is marked with VIRTIO_CONFIG_F_USED so it can't
80 * be found again. This version does endian conversion. */
81#define virtio_config_val(vdev, type, v) ({ \
82 int _err = __virtio_config_val((vdev),(type),(v),sizeof(*(v))); \
83 \
84 BUILD_BUG_ON(sizeof(*(v)) != 1 && sizeof(*(v)) != 2 \
85 && sizeof(*(v)) != 4 && sizeof(*(v)) != 8); \
86 if (!_err) { \
87 switch (sizeof(*(v))) { \
88 case 2: le16_to_cpus((__u16 *) v); break; \
89 case 4: le32_to_cpus((__u32 *) v); break; \
90 case 8: le64_to_cpus((__u64 *) v); break; \
91 } \
92 } \
93 _err; \
94})
95
96int __virtio_config_val(struct virtio_device *dev,
97 u8 type, void *val, size_t size);
98
99/**
100 * virtio_use_bit - helper to use a feature bit in a bitfield value.
101 * @dev: the virtio device
102 * @token: the token as returned from vdev->config->find().
103 * @len: the length of the field.
104 * @bitnum: the bit to test.
105 *
106 * If handed a NULL token, it returns false, otherwise returns bit status.
107 * If it's one, it sets the mirroring acknowledgement bit. */
108int virtio_use_bit(struct virtio_device *vdev,
109 void *token, unsigned int len, unsigned int bitnum);
110#endif /* __KERNEL__ */
111#endif /* _LINUX_VIRTIO_CONFIG_H */