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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 | /* Do we get callbacks when the ring is completely used, even if we've |
22 | * suppressed them? */ | |
23 | #define VIRTIO_F_NOTIFY_ON_EMPTY 24 | |
24 | ||
ec3d41c4 | 25 | #ifdef __KERNEL__ |
72e61eb4 | 26 | #include <linux/virtio.h> |
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27 | |
28 | /** | |
29 | * virtio_config_ops - operations for configuring a virtio device | |
a586d4f6 | 30 | * @get: read the value of a configuration field |
ec3d41c4 | 31 | * vdev: the virtio_device |
a586d4f6 | 32 | * offset: the offset of the configuration field |
ec3d41c4 | 33 | * buf: the buffer to write the field value into. |
a586d4f6 | 34 | * len: the length of the buffer |
a586d4f6 | 35 | * @set: write the value of a configuration field |
ec3d41c4 | 36 | * vdev: the virtio_device |
a586d4f6 | 37 | * offset: the offset of the configuration field |
ec3d41c4 | 38 | * buf: the buffer to read the field value from. |
a586d4f6 | 39 | * len: the length of the buffer |
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40 | * @get_status: read the status byte |
41 | * vdev: the virtio_device | |
42 | * Returns the status byte | |
43 | * @set_status: write the status byte | |
44 | * vdev: the virtio_device | |
45 | * status: the new status byte | |
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46 | * @reset: reset the device |
47 | * vdev: the virtio device | |
48 | * After this, status and feature negotiation must be done again | |
a586d4f6 | 49 | * @find_vq: find a virtqueue and instantiate it. |
ec3d41c4 | 50 | * vdev: the virtio_device |
a586d4f6 | 51 | * index: the 0-based virtqueue number in case there's more than one. |
ec3d41c4 | 52 | * callback: the virqtueue callback |
a586d4f6 | 53 | * Returns the new virtqueue or ERR_PTR() (eg. -ENOENT). |
ec3d41c4 | 54 | * @del_vq: free a virtqueue found by find_vq(). |
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55 | * @get_features: get the array of feature bits for this device. |
56 | * vdev: the virtio_device | |
57 | * Returns the first 32 feature bits (all we currently need). | |
58 | * @set_features: confirm what device features we'll be using. | |
59 | * vdev: the virtio_device | |
60 | * feature: the first 32 feature bits | |
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61 | */ |
62 | struct virtio_config_ops | |
63 | { | |
a586d4f6 | 64 | void (*get)(struct virtio_device *vdev, unsigned offset, |
ec3d41c4 | 65 | void *buf, unsigned len); |
a586d4f6 | 66 | void (*set)(struct virtio_device *vdev, unsigned offset, |
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67 | const void *buf, unsigned len); |
68 | u8 (*get_status)(struct virtio_device *vdev); | |
69 | void (*set_status)(struct virtio_device *vdev, u8 status); | |
6e5aa7ef | 70 | void (*reset)(struct virtio_device *vdev); |
ec3d41c4 | 71 | struct virtqueue *(*find_vq)(struct virtio_device *vdev, |
a586d4f6 | 72 | unsigned index, |
18445c4d | 73 | void (*callback)(struct virtqueue *)); |
ec3d41c4 | 74 | void (*del_vq)(struct virtqueue *vq); |
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75 | u32 (*get_features)(struct virtio_device *vdev); |
76 | void (*set_features)(struct virtio_device *vdev, u32 features); | |
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77 | }; |
78 | ||
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79 | /* If driver didn't advertise the feature, it will never appear. */ |
80 | void virtio_check_driver_offered_feature(const struct virtio_device *vdev, | |
81 | unsigned int fbit); | |
82 | ||
83 | /** | |
84 | * virtio_has_feature - helper to determine if this device has this feature. | |
85 | * @vdev: the device | |
86 | * @fbit: the feature bit | |
87 | */ | |
88 | static inline bool virtio_has_feature(const struct virtio_device *vdev, | |
89 | unsigned int fbit) | |
90 | { | |
91 | /* Did you forget to fix assumptions on max features? */ | |
92 | if (__builtin_constant_p(fbit)) | |
93 | BUILD_BUG_ON(fbit >= 32); | |
94 | ||
95 | virtio_check_driver_offered_feature(vdev, fbit); | |
96 | return test_bit(fbit, vdev->features); | |
97 | } | |
98 | ||
ec3d41c4 | 99 | /** |
72e61eb4 | 100 | * virtio_config_val - look for a feature and get a virtio config entry. |
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101 | * @vdev: the virtio device |
102 | * @fbit: the feature bit | |
103 | * @offset: the type to search for. | |
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104 | * @val: a pointer to the value to fill in. |
105 | * | |
a586d4f6 | 106 | * The return value is -ENOENT if the feature doesn't exist. Otherwise |
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107 | * the config value is copied into whatever is pointed to by v. */ |
108 | #define virtio_config_val(vdev, fbit, offset, v) \ | |
7f31fe05 | 109 | virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v)) |
ec3d41c4 | 110 | |
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111 | static inline int virtio_config_buf(struct virtio_device *vdev, |
112 | unsigned int fbit, | |
113 | unsigned int offset, | |
114 | void *buf, unsigned len) | |
115 | { | |
c45a6816 | 116 | if (!virtio_has_feature(vdev, fbit)) |
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117 | return -ENOENT; |
118 | ||
119 | vdev->config->get(vdev, offset, buf, len); | |
120 | return 0; | |
121 | } | |
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122 | #endif /* __KERNEL__ */ |
123 | #endif /* _LINUX_VIRTIO_CONFIG_H */ |