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1 | #ifndef _LINUX_VIRTIO_CONFIG_H |
2 | #define _LINUX_VIRTIO_CONFIG_H | |
3 | /* Virtio devices use a standardized configuration space to define their | |
4 | * features and pass configuration information, but each implementation can | |
5 | * store and access that space differently. */ | |
6 | #include <linux/types.h> | |
7 | ||
a586d4f6 | 8 | /* Status byte for guest to report progress, and synchronize features. */ |
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9 | /* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */ |
10 | #define VIRTIO_CONFIG_S_ACKNOWLEDGE 1 | |
11 | /* We have found a driver for the device. */ | |
12 | #define VIRTIO_CONFIG_S_DRIVER 2 | |
13 | /* Driver has used its parts of the config, and is happy */ | |
14 | #define VIRTIO_CONFIG_S_DRIVER_OK 4 | |
15 | /* We've given up on this device. */ | |
16 | #define VIRTIO_CONFIG_S_FAILED 0x80 | |
17 | ||
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18 | /* Do we get callbacks when the ring is completely used, even if we've |
19 | * suppressed them? */ | |
20 | #define VIRTIO_F_NOTIFY_ON_EMPTY 24 | |
21 | ||
ec3d41c4 | 22 | #ifdef __KERNEL__ |
72e61eb4 | 23 | #include <linux/virtio.h> |
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24 | |
25 | /** | |
26 | * virtio_config_ops - operations for configuring a virtio device | |
a586d4f6 | 27 | * @get: read the value of a configuration field |
ec3d41c4 | 28 | * vdev: the virtio_device |
a586d4f6 | 29 | * offset: the offset of the configuration field |
ec3d41c4 | 30 | * buf: the buffer to write the field value into. |
a586d4f6 | 31 | * len: the length of the buffer |
a586d4f6 | 32 | * @set: write the value of a configuration field |
ec3d41c4 | 33 | * vdev: the virtio_device |
a586d4f6 | 34 | * offset: the offset of the configuration field |
ec3d41c4 | 35 | * buf: the buffer to read the field value from. |
a586d4f6 | 36 | * len: the length of the buffer |
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37 | * @get_status: read the status byte |
38 | * vdev: the virtio_device | |
39 | * Returns the status byte | |
40 | * @set_status: write the status byte | |
41 | * vdev: the virtio_device | |
42 | * status: the new status byte | |
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43 | * @reset: reset the device |
44 | * vdev: the virtio device | |
45 | * After this, status and feature negotiation must be done again | |
a586d4f6 | 46 | * @find_vq: find a virtqueue and instantiate it. |
ec3d41c4 | 47 | * vdev: the virtio_device |
a586d4f6 | 48 | * index: the 0-based virtqueue number in case there's more than one. |
ec3d41c4 | 49 | * callback: the virqtueue callback |
a586d4f6 | 50 | * Returns the new virtqueue or ERR_PTR() (eg. -ENOENT). |
ec3d41c4 | 51 | * @del_vq: free a virtqueue found by find_vq(). |
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52 | * @get_features: get the array of feature bits for this device. |
53 | * vdev: the virtio_device | |
54 | * Returns the first 32 feature bits (all we currently need). | |
55 | * @set_features: confirm what device features we'll be using. | |
56 | * vdev: the virtio_device | |
57 | * feature: the first 32 feature bits | |
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58 | */ |
59 | struct virtio_config_ops | |
60 | { | |
a586d4f6 | 61 | void (*get)(struct virtio_device *vdev, unsigned offset, |
ec3d41c4 | 62 | void *buf, unsigned len); |
a586d4f6 | 63 | void (*set)(struct virtio_device *vdev, unsigned offset, |
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64 | const void *buf, unsigned len); |
65 | u8 (*get_status)(struct virtio_device *vdev); | |
66 | void (*set_status)(struct virtio_device *vdev, u8 status); | |
6e5aa7ef | 67 | void (*reset)(struct virtio_device *vdev); |
ec3d41c4 | 68 | struct virtqueue *(*find_vq)(struct virtio_device *vdev, |
a586d4f6 | 69 | unsigned index, |
18445c4d | 70 | void (*callback)(struct virtqueue *)); |
ec3d41c4 | 71 | void (*del_vq)(struct virtqueue *vq); |
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72 | u32 (*get_features)(struct virtio_device *vdev); |
73 | void (*set_features)(struct virtio_device *vdev, u32 features); | |
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74 | }; |
75 | ||
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76 | /* If driver didn't advertise the feature, it will never appear. */ |
77 | void virtio_check_driver_offered_feature(const struct virtio_device *vdev, | |
78 | unsigned int fbit); | |
79 | ||
80 | /** | |
81 | * virtio_has_feature - helper to determine if this device has this feature. | |
82 | * @vdev: the device | |
83 | * @fbit: the feature bit | |
84 | */ | |
85 | static inline bool virtio_has_feature(const struct virtio_device *vdev, | |
86 | unsigned int fbit) | |
87 | { | |
88 | /* Did you forget to fix assumptions on max features? */ | |
89 | if (__builtin_constant_p(fbit)) | |
90 | BUILD_BUG_ON(fbit >= 32); | |
91 | ||
92 | virtio_check_driver_offered_feature(vdev, fbit); | |
93 | return test_bit(fbit, vdev->features); | |
94 | } | |
95 | ||
ec3d41c4 | 96 | /** |
72e61eb4 | 97 | * virtio_config_val - look for a feature and get a virtio config entry. |
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98 | * @vdev: the virtio device |
99 | * @fbit: the feature bit | |
100 | * @offset: the type to search for. | |
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101 | * @val: a pointer to the value to fill in. |
102 | * | |
a586d4f6 | 103 | * The return value is -ENOENT if the feature doesn't exist. Otherwise |
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104 | * the config value is copied into whatever is pointed to by v. */ |
105 | #define virtio_config_val(vdev, fbit, offset, v) \ | |
7f31fe05 | 106 | virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v)) |
ec3d41c4 | 107 | |
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108 | static inline int virtio_config_buf(struct virtio_device *vdev, |
109 | unsigned int fbit, | |
110 | unsigned int offset, | |
111 | void *buf, unsigned len) | |
112 | { | |
c45a6816 | 113 | if (!virtio_has_feature(vdev, fbit)) |
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114 | return -ENOENT; |
115 | ||
116 | vdev->config->get(vdev, offset, buf, len); | |
117 | return 0; | |
118 | } | |
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119 | #endif /* __KERNEL__ */ |
120 | #endif /* _LINUX_VIRTIO_CONFIG_H */ |