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Rusty Russellec3d41c2007-10-22 11:03:36 +10001#ifndef _LINUX_VIRTIO_CONFIG_H
2#define _LINUX_VIRTIO_CONFIG_H
Rusty Russell674bfc22008-07-25 12:06:03 -05003/* This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
4 * anyone can use the definitions to implement compatible drivers/servers. */
5
Rusty Russellec3d41c2007-10-22 11:03:36 +10006/* 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
Rusty Russella586d4f2008-02-04 23:49:56 -050011/* Status byte for guest to report progress, and synchronize features. */
Rusty Russellec3d41c2007-10-22 11:03:36 +100012/* 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
Rusty Russelldd7c7bc2008-07-25 12:06:07 -050021/* 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
Rusty Russellb4f68be2008-05-30 15:09:45 -050027/* 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
Rusty Russellec3d41c2007-10-22 11:03:36 +100031#ifdef __KERNEL__
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -060032#include <linux/err.h>
Rusty Russell72e61eb2008-05-02 21:50:49 -050033#include <linux/virtio.h>
Rusty Russellec3d41c2007-10-22 11:03:36 +100034
35/**
36 * virtio_config_ops - operations for configuring a virtio device
Rusty Russella586d4f2008-02-04 23:49:56 -050037 * @get: read the value of a configuration field
Rusty Russellec3d41c2007-10-22 11:03:36 +100038 * vdev: the virtio_device
Rusty Russella586d4f2008-02-04 23:49:56 -050039 * offset: the offset of the configuration field
Rusty Russellec3d41c2007-10-22 11:03:36 +100040 * buf: the buffer to write the field value into.
Rusty Russella586d4f2008-02-04 23:49:56 -050041 * len: the length of the buffer
Rusty Russella586d4f2008-02-04 23:49:56 -050042 * @set: write the value of a configuration field
Rusty Russellec3d41c2007-10-22 11:03:36 +100043 * vdev: the virtio_device
Rusty Russella586d4f2008-02-04 23:49:56 -050044 * offset: the offset of the configuration field
Rusty Russellec3d41c2007-10-22 11:03:36 +100045 * buf: the buffer to read the field value from.
Rusty Russella586d4f2008-02-04 23:49:56 -050046 * len: the length of the buffer
Rusty Russellec3d41c2007-10-22 11:03:36 +100047 * @get_status: read the status byte
48 * vdev: the virtio_device
49 * Returns the status byte
50 * @set_status: write the status byte
51 * vdev: the virtio_device
52 * status: the new status byte
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -060053 * @request_vqs: request the specified number of virtqueues
54 * vdev: the virtio_device
55 * max_vqs: the max number of virtqueues we want
56 * If supplied, must call before any virtqueues are instantiated.
57 * To modify the max number of virtqueues after request_vqs has been
58 * called, call free_vqs and then request_vqs with a new value.
59 * @free_vqs: cleanup resources allocated by request_vqs
60 * vdev: the virtio_device
61 * If supplied, must call after all virtqueues have been deleted.
Rusty Russell6e5aa7e2008-02-04 23:50:03 -050062 * @reset: reset the device
63 * vdev: the virtio device
64 * After this, status and feature negotiation must be done again
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -060065 * @find_vqs: find virtqueues and instantiate them.
Rusty Russellec3d41c2007-10-22 11:03:36 +100066 * vdev: the virtio_device
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -060067 * nvqs: the number of virtqueues to find
68 * vqs: on success, includes new virtqueues
69 * callbacks: array of callbacks, for each virtqueue
70 * names: array of virtqueue names (mainly for debugging)
71 * Returns 0 on success or error status
72 * @del_vqs: free virtqueues found by find_vqs().
Rusty Russellc45a6812008-05-02 21:50:50 -050073 * @get_features: get the array of feature bits for this device.
74 * vdev: the virtio_device
75 * Returns the first 32 feature bits (all we currently need).
Rusty Russellc6248962008-07-25 12:06:07 -050076 * @finalize_features: confirm what device features we'll be using.
Rusty Russellc45a6812008-05-02 21:50:50 -050077 * vdev: the virtio_device
Rusty Russellc6248962008-07-25 12:06:07 -050078 * This gives the final feature bits for the device: it can change
79 * the dev->feature bits if it wants.
Rusty Russellec3d41c2007-10-22 11:03:36 +100080 */
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -060081typedef void vq_callback_t(struct virtqueue *);
Rusty Russellec3d41c2007-10-22 11:03:36 +100082struct virtio_config_ops
83{
Rusty Russella586d4f2008-02-04 23:49:56 -050084 void (*get)(struct virtio_device *vdev, unsigned offset,
Rusty Russellec3d41c2007-10-22 11:03:36 +100085 void *buf, unsigned len);
Rusty Russella586d4f2008-02-04 23:49:56 -050086 void (*set)(struct virtio_device *vdev, unsigned offset,
Rusty Russellec3d41c2007-10-22 11:03:36 +100087 const void *buf, unsigned len);
88 u8 (*get_status)(struct virtio_device *vdev);
89 void (*set_status)(struct virtio_device *vdev, u8 status);
Rusty Russell6e5aa7e2008-02-04 23:50:03 -050090 void (*reset)(struct virtio_device *vdev);
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -060091 int (*find_vqs)(struct virtio_device *, unsigned nvqs,
92 struct virtqueue *vqs[],
93 vq_callback_t *callbacks[],
94 const char *names[]);
95 void (*del_vqs)(struct virtio_device *);
Rusty Russellc45a6812008-05-02 21:50:50 -050096 u32 (*get_features)(struct virtio_device *vdev);
Rusty Russellc6248962008-07-25 12:06:07 -050097 void (*finalize_features)(struct virtio_device *vdev);
Rusty Russellec3d41c2007-10-22 11:03:36 +100098};
99
Rusty Russellc45a6812008-05-02 21:50:50 -0500100/* If driver didn't advertise the feature, it will never appear. */
101void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
102 unsigned int fbit);
103
104/**
105 * virtio_has_feature - helper to determine if this device has this feature.
106 * @vdev: the device
107 * @fbit: the feature bit
108 */
109static inline bool virtio_has_feature(const struct virtio_device *vdev,
110 unsigned int fbit)
111{
112 /* Did you forget to fix assumptions on max features? */
113 if (__builtin_constant_p(fbit))
114 BUILD_BUG_ON(fbit >= 32);
115
Mark McLoughlinee006b32009-05-11 18:11:44 +0100116 if (fbit < VIRTIO_TRANSPORT_F_START)
117 virtio_check_driver_offered_feature(vdev, fbit);
118
Rusty Russellc45a6812008-05-02 21:50:50 -0500119 return test_bit(fbit, vdev->features);
120}
121
Rusty Russellec3d41c2007-10-22 11:03:36 +1000122/**
Rusty Russell72e61eb2008-05-02 21:50:49 -0500123 * virtio_config_val - look for a feature and get a virtio config entry.
Rusty Russella586d4f2008-02-04 23:49:56 -0500124 * @vdev: the virtio device
125 * @fbit: the feature bit
126 * @offset: the type to search for.
Rusty Russellec3d41c2007-10-22 11:03:36 +1000127 * @val: a pointer to the value to fill in.
128 *
Rusty Russella586d4f2008-02-04 23:49:56 -0500129 * The return value is -ENOENT if the feature doesn't exist. Otherwise
Rusty Russell72e61eb2008-05-02 21:50:49 -0500130 * the config value is copied into whatever is pointed to by v. */
131#define virtio_config_val(vdev, fbit, offset, v) \
Christian Borntraeger7f31fe02008-05-29 11:08:01 +0200132 virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v))
Rusty Russellec3d41c2007-10-22 11:03:36 +1000133
Rusty Russell72e61eb2008-05-02 21:50:49 -0500134static inline int virtio_config_buf(struct virtio_device *vdev,
135 unsigned int fbit,
136 unsigned int offset,
137 void *buf, unsigned len)
138{
Rusty Russellc45a6812008-05-02 21:50:50 -0500139 if (!virtio_has_feature(vdev, fbit))
Rusty Russell72e61eb2008-05-02 21:50:49 -0500140 return -ENOENT;
141
142 vdev->config->get(vdev, offset, buf, len);
143 return 0;
144}
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -0600145
146static inline
147struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
148 vq_callback_t *c, const char *n)
149{
150 vq_callback_t *callbacks[] = { c };
151 const char *names[] = { n };
152 struct virtqueue *vq;
153 int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
154 if (err < 0)
155 return ERR_PTR(err);
156 return vq;
157}
Rusty Russellec3d41c2007-10-22 11:03:36 +1000158#endif /* __KERNEL__ */
159#endif /* _LINUX_VIRTIO_CONFIG_H */