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1 | #ifndef _LINUX_VIRTIO_CONFIG_H |
2 | #define _LINUX_VIRTIO_CONFIG_H | |
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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 | ||
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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__ |
72e61eb4 | 32 | #include <linux/virtio.h> |
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33 | |
34 | /** | |
35 | * virtio_config_ops - operations for configuring a virtio device | |
a586d4f6 | 36 | * @get: read the value of a configuration field |
ec3d41c4 | 37 | * vdev: the virtio_device |
a586d4f6 | 38 | * offset: the offset of the configuration field |
ec3d41c4 | 39 | * buf: the buffer to write the field value into. |
a586d4f6 | 40 | * len: the length of the buffer |
a586d4f6 | 41 | * @set: write the value of a configuration field |
ec3d41c4 | 42 | * vdev: the virtio_device |
a586d4f6 | 43 | * offset: the offset of the configuration field |
ec3d41c4 | 44 | * buf: the buffer to read the field value from. |
a586d4f6 | 45 | * len: the length of the buffer |
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46 | * @get_status: read the status byte |
47 | * vdev: the virtio_device | |
48 | * Returns the status byte | |
49 | * @set_status: write the status byte | |
50 | * vdev: the virtio_device | |
51 | * status: the new status byte | |
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52 | * @reset: reset the device |
53 | * vdev: the virtio device | |
54 | * After this, status and feature negotiation must be done again | |
a586d4f6 | 55 | * @find_vq: find a virtqueue and instantiate it. |
ec3d41c4 | 56 | * vdev: the virtio_device |
a586d4f6 | 57 | * index: the 0-based virtqueue number in case there's more than one. |
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58 | * callback: the virtqueue callback |
59 | * name: the virtqueue name (mainly for debugging) | |
a586d4f6 | 60 | * Returns the new virtqueue or ERR_PTR() (eg. -ENOENT). |
ec3d41c4 | 61 | * @del_vq: free a virtqueue found by find_vq(). |
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62 | * @get_features: get the array of feature bits for this device. |
63 | * vdev: the virtio_device | |
64 | * Returns the first 32 feature bits (all we currently need). | |
c624896e | 65 | * @finalize_features: confirm what device features we'll be using. |
c45a6816 | 66 | * vdev: the virtio_device |
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67 | * This gives the final feature bits for the device: it can change |
68 | * the dev->feature bits if it wants. | |
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69 | */ |
70 | struct virtio_config_ops | |
71 | { | |
a586d4f6 | 72 | void (*get)(struct virtio_device *vdev, unsigned offset, |
ec3d41c4 | 73 | void *buf, unsigned len); |
a586d4f6 | 74 | void (*set)(struct virtio_device *vdev, unsigned offset, |
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75 | const void *buf, unsigned len); |
76 | u8 (*get_status)(struct virtio_device *vdev); | |
77 | void (*set_status)(struct virtio_device *vdev, u8 status); | |
6e5aa7ef | 78 | void (*reset)(struct virtio_device *vdev); |
ec3d41c4 | 79 | struct virtqueue *(*find_vq)(struct virtio_device *vdev, |
a586d4f6 | 80 | unsigned index, |
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81 | void (*callback)(struct virtqueue *), |
82 | const char *name); | |
ec3d41c4 | 83 | void (*del_vq)(struct virtqueue *vq); |
c45a6816 | 84 | u32 (*get_features)(struct virtio_device *vdev); |
c624896e | 85 | void (*finalize_features)(struct virtio_device *vdev); |
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86 | }; |
87 | ||
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88 | /* If driver didn't advertise the feature, it will never appear. */ |
89 | void virtio_check_driver_offered_feature(const struct virtio_device *vdev, | |
90 | unsigned int fbit); | |
91 | ||
92 | /** | |
93 | * virtio_has_feature - helper to determine if this device has this feature. | |
94 | * @vdev: the device | |
95 | * @fbit: the feature bit | |
96 | */ | |
97 | static inline bool virtio_has_feature(const struct virtio_device *vdev, | |
98 | unsigned int fbit) | |
99 | { | |
100 | /* Did you forget to fix assumptions on max features? */ | |
101 | if (__builtin_constant_p(fbit)) | |
102 | BUILD_BUG_ON(fbit >= 32); | |
103 | ||
104 | virtio_check_driver_offered_feature(vdev, fbit); | |
105 | return test_bit(fbit, vdev->features); | |
106 | } | |
107 | ||
ec3d41c4 | 108 | /** |
72e61eb4 | 109 | * virtio_config_val - look for a feature and get a virtio config entry. |
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110 | * @vdev: the virtio device |
111 | * @fbit: the feature bit | |
112 | * @offset: the type to search for. | |
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113 | * @val: a pointer to the value to fill in. |
114 | * | |
a586d4f6 | 115 | * The return value is -ENOENT if the feature doesn't exist. Otherwise |
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116 | * the config value is copied into whatever is pointed to by v. */ |
117 | #define virtio_config_val(vdev, fbit, offset, v) \ | |
7f31fe05 | 118 | virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v)) |
ec3d41c4 | 119 | |
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120 | static inline int virtio_config_buf(struct virtio_device *vdev, |
121 | unsigned int fbit, | |
122 | unsigned int offset, | |
123 | void *buf, unsigned len) | |
124 | { | |
c45a6816 | 125 | if (!virtio_has_feature(vdev, fbit)) |
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126 | return -ENOENT; |
127 | ||
128 | vdev->config->get(vdev, offset, buf, len); | |
129 | return 0; | |
130 | } | |
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131 | #endif /* __KERNEL__ */ |
132 | #endif /* _LINUX_VIRTIO_CONFIG_H */ |