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 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of IBM nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 /* Virtio devices use a standardized configuration space to define their
30 * features and pass configuration information, but each implementation can
31 * store and access that space differently. */
32 #include <linux/types.h>
34 /* Status byte for guest to report progress, and synchronize features. */
35 /* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */
36 #define VIRTIO_CONFIG_S_ACKNOWLEDGE 1
37 /* We have found a driver for the device. */
38 #define VIRTIO_CONFIG_S_DRIVER 2
39 /* Driver has used its parts of the config, and is happy */
40 #define VIRTIO_CONFIG_S_DRIVER_OK 4
41 /* We've given up on this device. */
42 #define VIRTIO_CONFIG_S_FAILED 0x80
44 /* Some virtio feature bits (currently bits 28 through 31) are reserved for the
45 * transport being used (eg. virtio_ring), the rest are per-device feature
47 #define VIRTIO_TRANSPORT_F_START 28
48 #define VIRTIO_TRANSPORT_F_END 32
50 /* Do we get callbacks when the ring is completely used, even if we've
52 #define VIRTIO_F_NOTIFY_ON_EMPTY 24
55 #include <linux/err.h>
56 #include <linux/virtio.h>
59 * virtio_config_ops - operations for configuring a virtio device
60 * @get: read the value of a configuration field
61 * vdev: the virtio_device
62 * offset: the offset of the configuration field
63 * buf: the buffer to write the field value into.
64 * len: the length of the buffer
65 * @set: write the value of a configuration field
66 * vdev: the virtio_device
67 * offset: the offset of the configuration field
68 * buf: the buffer to read the field value from.
69 * len: the length of the buffer
70 * @get_status: read the status byte
71 * vdev: the virtio_device
72 * Returns the status byte
73 * @set_status: write the status byte
74 * vdev: the virtio_device
75 * status: the new status byte
76 * @request_vqs: request the specified number of virtqueues
77 * vdev: the virtio_device
78 * max_vqs: the max number of virtqueues we want
79 * If supplied, must call before any virtqueues are instantiated.
80 * To modify the max number of virtqueues after request_vqs has been
81 * called, call free_vqs and then request_vqs with a new value.
82 * @free_vqs: cleanup resources allocated by request_vqs
83 * vdev: the virtio_device
84 * If supplied, must call after all virtqueues have been deleted.
85 * @reset: reset the device
86 * vdev: the virtio device
87 * After this, status and feature negotiation must be done again
88 * Device must not be reset from its vq/config callbacks, or in
89 * parallel with being added/removed.
90 * @find_vqs: find virtqueues and instantiate them.
91 * vdev: the virtio_device
92 * nvqs: the number of virtqueues to find
93 * vqs: on success, includes new virtqueues
94 * callbacks: array of callbacks, for each virtqueue
95 * names: array of virtqueue names (mainly for debugging)
96 * Returns 0 on success or error status
97 * @del_vqs: free virtqueues found by find_vqs().
98 * @get_features: get the array of feature bits for this device.
99 * vdev: the virtio_device
100 * Returns the first 32 feature bits (all we currently need).
101 * @finalize_features: confirm what device features we'll be using.
102 * vdev: the virtio_device
103 * This gives the final feature bits for the device: it can change
104 * the dev->feature bits if it wants.
105 * @bus_name: return the bus name associated with the device
106 * vdev: the virtio_device
107 * This returns a pointer to the bus name a la pci_name from which
108 * the caller can then copy.
110 typedef void vq_callback_t(struct virtqueue
*);
111 struct virtio_config_ops
{
112 void (*get
)(struct virtio_device
*vdev
, unsigned offset
,
113 void *buf
, unsigned len
);
114 void (*set
)(struct virtio_device
*vdev
, unsigned offset
,
115 const void *buf
, unsigned len
);
116 u8 (*get_status
)(struct virtio_device
*vdev
);
117 void (*set_status
)(struct virtio_device
*vdev
, u8 status
);
118 void (*reset
)(struct virtio_device
*vdev
);
119 int (*find_vqs
)(struct virtio_device
*, unsigned nvqs
,
120 struct virtqueue
*vqs
[],
121 vq_callback_t
*callbacks
[],
122 const char *names
[]);
123 void (*del_vqs
)(struct virtio_device
*);
124 u32 (*get_features
)(struct virtio_device
*vdev
);
125 void (*finalize_features
)(struct virtio_device
*vdev
);
126 const char *(*bus_name
)(struct virtio_device
*vdev
);
129 /* If driver didn't advertise the feature, it will never appear. */
130 void virtio_check_driver_offered_feature(const struct virtio_device
*vdev
,
134 * virtio_has_feature - helper to determine if this device has this feature.
136 * @fbit: the feature bit
138 static inline bool virtio_has_feature(const struct virtio_device
*vdev
,
141 /* Did you forget to fix assumptions on max features? */
142 if (__builtin_constant_p(fbit
))
143 BUILD_BUG_ON(fbit
>= 32);
147 if (fbit
< VIRTIO_TRANSPORT_F_START
)
148 virtio_check_driver_offered_feature(vdev
, fbit
);
150 return test_bit(fbit
, vdev
->features
);
154 * virtio_config_val - look for a feature and get a virtio config entry.
155 * @vdev: the virtio device
156 * @fbit: the feature bit
157 * @offset: the type to search for.
158 * @val: a pointer to the value to fill in.
160 * The return value is -ENOENT if the feature doesn't exist. Otherwise
161 * the config value is copied into whatever is pointed to by v. */
162 #define virtio_config_val(vdev, fbit, offset, v) \
163 virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v))
165 #define virtio_config_val_len(vdev, fbit, offset, v, len) \
166 virtio_config_buf((vdev), (fbit), (offset), (v), (len))
168 static inline int virtio_config_buf(struct virtio_device
*vdev
,
171 void *buf
, unsigned len
)
173 if (!virtio_has_feature(vdev
, fbit
))
176 vdev
->config
->get(vdev
, offset
, buf
, len
);
181 struct virtqueue
*virtio_find_single_vq(struct virtio_device
*vdev
,
182 vq_callback_t
*c
, const char *n
)
184 vq_callback_t
*callbacks
[] = { c
};
185 const char *names
[] = { n
};
186 struct virtqueue
*vq
;
187 int err
= vdev
->config
->find_vqs(vdev
, 1, &vq
, callbacks
, names
);
194 const char *virtio_bus_name(struct virtio_device
*vdev
)
196 if (!vdev
->config
->bus_name
)
198 return vdev
->config
->bus_name(vdev
);
201 #endif /* __KERNEL__ */
202 #endif /* _LINUX_VIRTIO_CONFIG_H */
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