1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef LINUX_VIRTIO_CONFIG_H
3 #define LINUX_VIRTIO_CONFIG_H
4 #include <linux/virtio_byteorder.h>
5 #include <linux/virtio.h>
6 #include <uapi/linux/virtio_config.h>
7
8 struct virtio_config_ops {
9 int (*disable_vq_and_reset)(struct virtqueue *vq);
10 int (*enable_vq_after_reset)(struct virtqueue *vq);
11 };
12
13 /*
14 * __virtio_test_bit - helper to test feature bits. For use by transports.
15 * Devices should normally use virtio_has_feature,
16 * which includes more checks.
17 * @vdev: the device
18 * @fbit: the feature bit
19 */
20 static inline bool __virtio_test_bit(const struct virtio_device *vdev,
21 unsigned int fbit)
22 {
23 return vdev->features & (1ULL << fbit);
24 }
25
26 /**
27 * __virtio_set_bit - helper to set feature bits. For use by transports.
28 * @vdev: the device
29 * @fbit: the feature bit
30 */
31 static inline void __virtio_set_bit(struct virtio_device *vdev,
32 unsigned int fbit)
33 {
34 vdev->features |= (1ULL << fbit);
35 }
36
37 /**
38 * __virtio_clear_bit - helper to clear feature bits. For use by transports.
39 * @vdev: the device
40 * @fbit: the feature bit
41 */
42 static inline void __virtio_clear_bit(struct virtio_device *vdev,
43 unsigned int fbit)
44 {
45 vdev->features &= ~(1ULL << fbit);
46 }
47
48 #define virtio_has_feature(dev, feature) \
49 (__virtio_test_bit((dev), feature))
50
51 /**
52 * virtio_has_dma_quirk - determine whether this device has the DMA quirk
53 * @vdev: the device
54 */
55 static inline bool virtio_has_dma_quirk(const struct virtio_device *vdev)
56 {
57 /*
58 * Note the reverse polarity of the quirk feature (compared to most
59 * other features), this is for compatibility with legacy systems.
60 */
61 return !virtio_has_feature(vdev, VIRTIO_F_ACCESS_PLATFORM);
62 }
63
64 static inline bool virtio_is_little_endian(struct virtio_device *vdev)
65 {
66 return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
67 virtio_legacy_is_little_endian();
68 }
69
70 /* Memory accessors */
71 static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
72 {
73 return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
74 }
75
76 static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
77 {
78 return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
79 }
80
81 static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
82 {
83 return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
84 }
85
86 static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
87 {
88 return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
89 }
90
91 static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
92 {
93 return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
94 }
95
96 static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
97 {
98 return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
99 }
100
101 #endif
102
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