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1 | #ifndef _LINUX_VIRTIO_CONFIG_H |
2 | #define _LINUX_VIRTIO_CONFIG_H | |
674bfc23 RR |
3 | /* This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so |
4 | * anyone can use the definitions to implement compatible drivers/servers. */ | |
5 | ||
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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 | ||
a586d4f6 | 11 | /* Status byte for guest to report progress, and synchronize features. */ |
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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 | ||
dd7c7bc4 RR |
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 | ||
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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 | ||
ec3d41c4 | 31 | #ifdef __KERNEL__ |
d2a7ddda | 32 | #include <linux/err.h> |
72e61eb4 | 33 | #include <linux/virtio.h> |
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34 | |
35 | /** | |
36 | * virtio_config_ops - operations for configuring a virtio device | |
a586d4f6 | 37 | * @get: read the value of a configuration field |
ec3d41c4 | 38 | * vdev: the virtio_device |
a586d4f6 | 39 | * offset: the offset of the configuration field |
ec3d41c4 | 40 | * buf: the buffer to write the field value into. |
a586d4f6 | 41 | * len: the length of the buffer |
a586d4f6 | 42 | * @set: write the value of a configuration field |
ec3d41c4 | 43 | * vdev: the virtio_device |
a586d4f6 | 44 | * offset: the offset of the configuration field |
ec3d41c4 | 45 | * buf: the buffer to read the field value from. |
a586d4f6 | 46 | * len: the length of the buffer |
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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 | |
d2a7ddda MT |
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. | |
6e5aa7ef RR |
62 | * @reset: reset the device |
63 | * vdev: the virtio device | |
64 | * After this, status and feature negotiation must be done again | |
d2a7ddda | 65 | * @find_vqs: find virtqueues and instantiate them. |
ec3d41c4 | 66 | * vdev: the virtio_device |
d2a7ddda MT |
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(). | |
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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). | |
c624896e | 76 | * @finalize_features: confirm what device features we'll be using. |
c45a6816 | 77 | * vdev: the virtio_device |
c624896e RR |
78 | * This gives the final feature bits for the device: it can change |
79 | * the dev->feature bits if it wants. | |
ec3d41c4 | 80 | */ |
d2a7ddda | 81 | typedef void vq_callback_t(struct virtqueue *); |
1842f23c | 82 | struct virtio_config_ops { |
a586d4f6 | 83 | void (*get)(struct virtio_device *vdev, unsigned offset, |
ec3d41c4 | 84 | void *buf, unsigned len); |
a586d4f6 | 85 | void (*set)(struct virtio_device *vdev, unsigned offset, |
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86 | const void *buf, unsigned len); |
87 | u8 (*get_status)(struct virtio_device *vdev); | |
88 | void (*set_status)(struct virtio_device *vdev, u8 status); | |
6e5aa7ef | 89 | void (*reset)(struct virtio_device *vdev); |
d2a7ddda MT |
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 *); | |
c45a6816 | 95 | u32 (*get_features)(struct virtio_device *vdev); |
c624896e | 96 | void (*finalize_features)(struct virtio_device *vdev); |
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97 | }; |
98 | ||
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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? */ | |
8c87df45 | 112 | MAYBE_BUILD_BUG_ON(fbit >= 32); |
c45a6816 | 113 | |
ee006b35 MM |
114 | if (fbit < VIRTIO_TRANSPORT_F_START) |
115 | virtio_check_driver_offered_feature(vdev, fbit); | |
116 | ||
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117 | return test_bit(fbit, vdev->features); |
118 | } | |
119 | ||
ec3d41c4 | 120 | /** |
72e61eb4 | 121 | * virtio_config_val - look for a feature and get a virtio config entry. |
a586d4f6 RR |
122 | * @vdev: the virtio device |
123 | * @fbit: the feature bit | |
124 | * @offset: the type to search for. | |
ec3d41c4 RR |
125 | * @val: a pointer to the value to fill in. |
126 | * | |
a586d4f6 | 127 | * The return value is -ENOENT if the feature doesn't exist. Otherwise |
72e61eb4 RR |
128 | * the config value is copied into whatever is pointed to by v. */ |
129 | #define virtio_config_val(vdev, fbit, offset, v) \ | |
7f31fe05 | 130 | virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v)) |
ec3d41c4 | 131 | |
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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 | { | |
c45a6816 | 137 | if (!virtio_has_feature(vdev, fbit)) |
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138 | return -ENOENT; |
139 | ||
140 | vdev->config->get(vdev, offset, buf, len); | |
141 | return 0; | |
142 | } | |
d2a7ddda MT |
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 | } | |
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156 | #endif /* __KERNEL__ */ |
157 | #endif /* _LINUX_VIRTIO_CONFIG_H */ |