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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. */ |
5 | |
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> |
10 | |
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 |
20 | |
21 | /* Some virtio feature bits (currently bits 28 through 31) are reserved for the |
22 | * transport being used (eg. virtio_ring), the rest are per-device feature |
23 | * bits. */ |
24 | #define VIRTIO_TRANSPORT_F_START 28 |
25 | #define VIRTIO_TRANSPORT_F_END 32 |
26 | |
27 | /* Do we get callbacks when the ring is completely used, even if we've |
28 | * suppressed them? */ |
29 | #define VIRTIO_F_NOTIFY_ON_EMPTY 24 |
30 | |
31 | #ifdef __KERNEL__ |
32 | #include <linux/err.h> |
33 | #include <linux/virtio.h> |
34 | |
35 | /** |
36 | * virtio_config_ops - operations for configuring a virtio device |
37 | * @get: read the value of a configuration field |
38 | * vdev: the virtio_device |
39 | * offset: the offset of the configuration field |
40 | * buf: the buffer to write the field value into. |
41 | * len: the length of the buffer |
42 | * @set: write the value of a configuration field |
43 | * vdev: the virtio_device |
44 | * offset: the offset of the configuration field |
45 | * buf: the buffer to read the field value from. |
46 | * len: the length of the buffer |
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 | * @request_vqs: request the specified number of virtqueues |
54 | * vdev: the virtio_device |
55 | * max_vqs: the max number of virtqueues we want |
56 | * If supplied, must call before any virtqueues are instantiated. |
57 | * To modify the max number of virtqueues after request_vqs has been |
58 | * called, call free_vqs and then request_vqs with a new value. |
59 | * @free_vqs: cleanup resources allocated by request_vqs |
60 | * vdev: the virtio_device |
61 | * If supplied, must call after all virtqueues have been deleted. |
62 | * @reset: reset the device |
63 | * vdev: the virtio device |
64 | * After this, status and feature negotiation must be done again |
65 | * @find_vqs: find virtqueues and instantiate them. |
66 | * vdev: the virtio_device |
67 | * nvqs: the number of virtqueues to find |
68 | * vqs: on success, includes new virtqueues |
69 | * callbacks: array of callbacks, for each virtqueue |
70 | * names: array of virtqueue names (mainly for debugging) |
71 | * Returns 0 on success or error status |
72 | * @del_vqs: free virtqueues found by find_vqs(). |
73 | * @get_features: get the array of feature bits for this device. |
74 | * vdev: the virtio_device |
75 | * Returns the first 32 feature bits (all we currently need). |
76 | * @finalize_features: confirm what device features we'll be using. |
77 | * vdev: the virtio_device |
78 | * This gives the final feature bits for the device: it can change |
79 | * the dev->feature bits if it wants. |
80 | */ |
81 | typedef void vq_callback_t(struct virtqueue *); |
82 | struct virtio_config_ops { |
83 | void (*get)(struct virtio_device *vdev, unsigned offset, |
84 | void *buf, unsigned len); |
85 | void (*set)(struct virtio_device *vdev, unsigned offset, |
86 | const void *buf, unsigned len); |
87 | u8 (*get_status)(struct virtio_device *vdev); |
88 | void (*set_status)(struct virtio_device *vdev, u8 status); |
89 | void (*reset)(struct virtio_device *vdev); |
90 | int (*find_vqs)(struct virtio_device *, unsigned nvqs, |
91 | struct virtqueue *vqs[], |
92 | vq_callback_t *callbacks[], |
93 | const char *names[]); |
94 | void (*del_vqs)(struct virtio_device *); |
95 | u32 (*get_features)(struct virtio_device *vdev); |
96 | void (*finalize_features)(struct virtio_device *vdev); |
97 | }; |
98 | |
99 | /* If driver didn't advertise the feature, it will never appear. */ |
100 | void virtio_check_driver_offered_feature(const struct virtio_device *vdev, |
101 | unsigned int fbit); |
102 | |
103 | /** |
104 | * virtio_has_feature - helper to determine if this device has this feature. |
105 | * @vdev: the device |
106 | * @fbit: the feature bit |
107 | */ |
108 | static inline bool virtio_has_feature(const struct virtio_device *vdev, |
109 | unsigned int fbit) |
110 | { |
111 | /* Did you forget to fix assumptions on max features? */ |
112 | MAYBE_BUILD_BUG_ON(fbit >= 32); |
113 | |
114 | if (fbit < VIRTIO_TRANSPORT_F_START) |
115 | virtio_check_driver_offered_feature(vdev, fbit); |
116 | |
117 | return test_bit(fbit, vdev->features); |
118 | } |
119 | |
120 | /** |
121 | * virtio_config_val - look for a feature and get a virtio config entry. |
122 | * @vdev: the virtio device |
123 | * @fbit: the feature bit |
124 | * @offset: the type to search for. |
125 | * @val: a pointer to the value to fill in. |
126 | * |
127 | * The return value is -ENOENT if the feature doesn't exist. Otherwise |
128 | * the config value is copied into whatever is pointed to by v. */ |
129 | #define virtio_config_val(vdev, fbit, offset, v) \ |
130 | virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v)) |
131 | |
132 | static inline int virtio_config_buf(struct virtio_device *vdev, |
133 | unsigned int fbit, |
134 | unsigned int offset, |
135 | void *buf, unsigned len) |
136 | { |
137 | if (!virtio_has_feature(vdev, fbit)) |
138 | return -ENOENT; |
139 | |
140 | vdev->config->get(vdev, offset, buf, len); |
141 | return 0; |
142 | } |
143 | |
144 | static inline |
145 | struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev, |
146 | vq_callback_t *c, const char *n) |
147 | { |
148 | vq_callback_t *callbacks[] = { c }; |
149 | const char *names[] = { n }; |
150 | struct virtqueue *vq; |
151 | int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names); |
152 | if (err < 0) |
153 | return ERR_PTR(err); |
154 | return vq; |
155 | } |
156 | #endif /* __KERNEL__ */ |
157 | #endif /* _LINUX_VIRTIO_CONFIG_H */ |
158 |
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od-2011-09-04
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v2.6.34-rc5
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