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ec3d41c4 RR |
1 | #ifndef _LINUX_VIRTIO_CONFIG_H |
2 | #define _LINUX_VIRTIO_CONFIG_H | |
674bfc23 | 3 | /* This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so |
a1b38387 RR |
4 | * anyone can use the definitions to implement compatible drivers/servers. |
5 | * | |
6 | * Redistribution and use in source and binary forms, with or without | |
7 | * modification, are permitted provided that the following conditions | |
8 | * are met: | |
9 | * 1. Redistributions of source code must retain the above copyright | |
10 | * notice, this list of conditions and the following disclaimer. | |
11 | * 2. Redistributions in binary form must reproduce the above copyright | |
12 | * notice, this list of conditions and the following disclaimer in the | |
13 | * documentation and/or other materials provided with the distribution. | |
14 | * 3. Neither the name of IBM nor the names of its contributors | |
15 | * may be used to endorse or promote products derived from this software | |
16 | * without specific prior written permission. | |
17 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND | |
18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
20 | * ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE | |
21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
27 | * SUCH DAMAGE. */ | |
674bfc23 | 28 | |
ec3d41c4 RR |
29 | /* Virtio devices use a standardized configuration space to define their |
30 | * features and pass configuration information, but each implementation can | |
31 | * store and access that space differently. */ | |
32 | #include <linux/types.h> | |
33 | ||
a586d4f6 | 34 | /* Status byte for guest to report progress, and synchronize features. */ |
ec3d41c4 RR |
35 | /* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */ |
36 | #define VIRTIO_CONFIG_S_ACKNOWLEDGE 1 | |
37 | /* We have found a driver for the device. */ | |
38 | #define VIRTIO_CONFIG_S_DRIVER 2 | |
39 | /* Driver has used its parts of the config, and is happy */ | |
40 | #define VIRTIO_CONFIG_S_DRIVER_OK 4 | |
41 | /* We've given up on this device. */ | |
42 | #define VIRTIO_CONFIG_S_FAILED 0x80 | |
43 | ||
dd7c7bc4 RR |
44 | /* Some virtio feature bits (currently bits 28 through 31) are reserved for the |
45 | * transport being used (eg. virtio_ring), the rest are per-device feature | |
46 | * bits. */ | |
47 | #define VIRTIO_TRANSPORT_F_START 28 | |
48 | #define VIRTIO_TRANSPORT_F_END 32 | |
49 | ||
b4f68be6 RR |
50 | /* Do we get callbacks when the ring is completely used, even if we've |
51 | * suppressed them? */ | |
52 | #define VIRTIO_F_NOTIFY_ON_EMPTY 24 | |
53 | ||
ec3d41c4 | 54 | #ifdef __KERNEL__ |
d2a7ddda | 55 | #include <linux/err.h> |
72e61eb4 | 56 | #include <linux/virtio.h> |
ec3d41c4 RR |
57 | |
58 | /** | |
59 | * virtio_config_ops - operations for configuring a virtio device | |
a586d4f6 | 60 | * @get: read the value of a configuration field |
ec3d41c4 | 61 | * vdev: the virtio_device |
a586d4f6 | 62 | * offset: the offset of the configuration field |
ec3d41c4 | 63 | * buf: the buffer to write the field value into. |
a586d4f6 | 64 | * len: the length of the buffer |
a586d4f6 | 65 | * @set: write the value of a configuration field |
ec3d41c4 | 66 | * vdev: the virtio_device |
a586d4f6 | 67 | * offset: the offset of the configuration field |
ec3d41c4 | 68 | * buf: the buffer to read the field value from. |
a586d4f6 | 69 | * len: the length of the buffer |
ec3d41c4 RR |
70 | * @get_status: read the status byte |
71 | * vdev: the virtio_device | |
72 | * Returns the status byte | |
73 | * @set_status: write the status byte | |
74 | * vdev: the virtio_device | |
75 | * status: the new status byte | |
d2a7ddda MT |
76 | * @request_vqs: request the specified number of virtqueues |
77 | * vdev: the virtio_device | |
78 | * max_vqs: the max number of virtqueues we want | |
79 | * If supplied, must call before any virtqueues are instantiated. | |
80 | * To modify the max number of virtqueues after request_vqs has been | |
81 | * called, call free_vqs and then request_vqs with a new value. | |
82 | * @free_vqs: cleanup resources allocated by request_vqs | |
83 | * vdev: the virtio_device | |
84 | * If supplied, must call after all virtqueues have been deleted. | |
6e5aa7ef RR |
85 | * @reset: reset the device |
86 | * vdev: the virtio device | |
87 | * After this, status and feature negotiation must be done again | |
e6af578c MT |
88 | * Device must not be reset from its vq/config callbacks, or in |
89 | * parallel with being added/removed. | |
d2a7ddda | 90 | * @find_vqs: find virtqueues and instantiate them. |
ec3d41c4 | 91 | * vdev: the virtio_device |
d2a7ddda MT |
92 | * nvqs: the number of virtqueues to find |
93 | * vqs: on success, includes new virtqueues | |
94 | * callbacks: array of callbacks, for each virtqueue | |
95 | * names: array of virtqueue names (mainly for debugging) | |
96 | * Returns 0 on success or error status | |
97 | * @del_vqs: free virtqueues found by find_vqs(). | |
c45a6816 RR |
98 | * @get_features: get the array of feature bits for this device. |
99 | * vdev: the virtio_device | |
100 | * Returns the first 32 feature bits (all we currently need). | |
c624896e | 101 | * @finalize_features: confirm what device features we'll be using. |
c45a6816 | 102 | * vdev: the virtio_device |
c624896e RR |
103 | * This gives the final feature bits for the device: it can change |
104 | * the dev->feature bits if it wants. | |
66846048 RJ |
105 | * @bus_name: return the bus name associated with the device |
106 | * vdev: the virtio_device | |
107 | * This returns a pointer to the bus name a la pci_name from which | |
108 | * the caller can then copy. | |
ec3d41c4 | 109 | */ |
d2a7ddda | 110 | typedef void vq_callback_t(struct virtqueue *); |
1842f23c | 111 | struct virtio_config_ops { |
a586d4f6 | 112 | void (*get)(struct virtio_device *vdev, unsigned offset, |
ec3d41c4 | 113 | void *buf, unsigned len); |
a586d4f6 | 114 | void (*set)(struct virtio_device *vdev, unsigned offset, |
ec3d41c4 RR |
115 | const void *buf, unsigned len); |
116 | u8 (*get_status)(struct virtio_device *vdev); | |
117 | void (*set_status)(struct virtio_device *vdev, u8 status); | |
6e5aa7ef | 118 | void (*reset)(struct virtio_device *vdev); |
d2a7ddda MT |
119 | int (*find_vqs)(struct virtio_device *, unsigned nvqs, |
120 | struct virtqueue *vqs[], | |
121 | vq_callback_t *callbacks[], | |
122 | const char *names[]); | |
123 | void (*del_vqs)(struct virtio_device *); | |
c45a6816 | 124 | u32 (*get_features)(struct virtio_device *vdev); |
c624896e | 125 | void (*finalize_features)(struct virtio_device *vdev); |
66846048 | 126 | const char *(*bus_name)(struct virtio_device *vdev); |
ec3d41c4 RR |
127 | }; |
128 | ||
c45a6816 RR |
129 | /* If driver didn't advertise the feature, it will never appear. */ |
130 | void virtio_check_driver_offered_feature(const struct virtio_device *vdev, | |
131 | unsigned int fbit); | |
132 | ||
133 | /** | |
134 | * virtio_has_feature - helper to determine if this device has this feature. | |
135 | * @vdev: the device | |
136 | * @fbit: the feature bit | |
137 | */ | |
138 | static inline bool virtio_has_feature(const struct virtio_device *vdev, | |
139 | unsigned int fbit) | |
140 | { | |
141 | /* Did you forget to fix assumptions on max features? */ | |
1765e3a4 RR |
142 | if (__builtin_constant_p(fbit)) |
143 | BUILD_BUG_ON(fbit >= 32); | |
144 | else | |
145 | BUG_ON(fbit >= 32); | |
c45a6816 | 146 | |
ee006b35 MM |
147 | if (fbit < VIRTIO_TRANSPORT_F_START) |
148 | virtio_check_driver_offered_feature(vdev, fbit); | |
149 | ||
c45a6816 RR |
150 | return test_bit(fbit, vdev->features); |
151 | } | |
152 | ||
ec3d41c4 | 153 | /** |
72e61eb4 | 154 | * virtio_config_val - look for a feature and get a virtio config entry. |
a586d4f6 RR |
155 | * @vdev: the virtio device |
156 | * @fbit: the feature bit | |
157 | * @offset: the type to search for. | |
ec3d41c4 RR |
158 | * @val: a pointer to the value to fill in. |
159 | * | |
a586d4f6 | 160 | * The return value is -ENOENT if the feature doesn't exist. Otherwise |
72e61eb4 RR |
161 | * the config value is copied into whatever is pointed to by v. */ |
162 | #define virtio_config_val(vdev, fbit, offset, v) \ | |
7f31fe05 | 163 | virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v)) |
ec3d41c4 | 164 | |
3ead6f4d SL |
165 | #define virtio_config_val_len(vdev, fbit, offset, v, len) \ |
166 | virtio_config_buf((vdev), (fbit), (offset), (v), (len)) | |
167 | ||
72e61eb4 RR |
168 | static inline int virtio_config_buf(struct virtio_device *vdev, |
169 | unsigned int fbit, | |
170 | unsigned int offset, | |
171 | void *buf, unsigned len) | |
172 | { | |
c45a6816 | 173 | if (!virtio_has_feature(vdev, fbit)) |
72e61eb4 RR |
174 | return -ENOENT; |
175 | ||
176 | vdev->config->get(vdev, offset, buf, len); | |
177 | return 0; | |
178 | } | |
d2a7ddda MT |
179 | |
180 | static inline | |
181 | struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev, | |
182 | vq_callback_t *c, const char *n) | |
183 | { | |
184 | vq_callback_t *callbacks[] = { c }; | |
185 | const char *names[] = { n }; | |
186 | struct virtqueue *vq; | |
187 | int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names); | |
188 | if (err < 0) | |
189 | return ERR_PTR(err); | |
190 | return vq; | |
191 | } | |
66846048 RJ |
192 | |
193 | static inline | |
194 | const char *virtio_bus_name(struct virtio_device *vdev) | |
195 | { | |
196 | if (!vdev->config->bus_name) | |
197 | return "virtio"; | |
198 | return vdev->config->bus_name(vdev); | |
199 | } | |
200 | ||
ec3d41c4 RR |
201 | #endif /* __KERNEL__ */ |
202 | #endif /* _LINUX_VIRTIO_CONFIG_H */ |