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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
Rusty Russella1b38382011-05-30 11:14:13 -06004 * 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. */
Rusty Russell674bfc22008-07-25 12:06:03 -050028
Rusty Russellec3d41c2007-10-22 11:03:36 +100029/* 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
Rusty Russella586d4f2008-02-04 23:49:56 -050034/* Status byte for guest to report progress, and synchronize features. */
Rusty Russellec3d41c2007-10-22 11:03:36 +100035/* 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
Rusty Russelldd7c7bc2008-07-25 12:06:07 -050044/* 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
Rusty Russellb4f68be2008-05-30 15:09:45 -050050/* 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
Rusty Russellec3d41c2007-10-22 11:03:36 +100054#ifdef __KERNEL__
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -060055#include <linux/err.h>
Rusty Russell72e61eb2008-05-02 21:50:49 -050056#include <linux/virtio.h>
Rusty Russellec3d41c2007-10-22 11:03:36 +100057
58/**
59 * virtio_config_ops - operations for configuring a virtio device
Rusty Russella586d4f2008-02-04 23:49:56 -050060 * @get: read the value of a configuration field
Rusty Russellec3d41c2007-10-22 11:03:36 +100061 * vdev: the virtio_device
Rusty Russella586d4f2008-02-04 23:49:56 -050062 * offset: the offset of the configuration field
Rusty Russellec3d41c2007-10-22 11:03:36 +100063 * buf: the buffer to write the field value into.
Rusty Russella586d4f2008-02-04 23:49:56 -050064 * len: the length of the buffer
Rusty Russella586d4f2008-02-04 23:49:56 -050065 * @set: write the value of a configuration field
Rusty Russellec3d41c2007-10-22 11:03:36 +100066 * vdev: the virtio_device
Rusty Russella586d4f2008-02-04 23:49:56 -050067 * offset: the offset of the configuration field
Rusty Russellec3d41c2007-10-22 11:03:36 +100068 * buf: the buffer to read the field value from.
Rusty Russella586d4f2008-02-04 23:49:56 -050069 * len: the length of the buffer
Rusty Russellec3d41c2007-10-22 11:03:36 +100070 * @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
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -060076 * @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.
Rusty Russell6e5aa7e2008-02-04 23:50:03 -050085 * @reset: reset the device
86 * vdev: the virtio device
87 * After this, status and feature negotiation must be done again
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -060088 * @find_vqs: find virtqueues and instantiate them.
Rusty Russellec3d41c2007-10-22 11:03:36 +100089 * vdev: the virtio_device
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -060090 * nvqs: the number of virtqueues to find
91 * vqs: on success, includes new virtqueues
92 * callbacks: array of callbacks, for each virtqueue
93 * names: array of virtqueue names (mainly for debugging)
94 * Returns 0 on success or error status
95 * @del_vqs: free virtqueues found by find_vqs().
Rusty Russellc45a6812008-05-02 21:50:50 -050096 * @get_features: get the array of feature bits for this device.
97 * vdev: the virtio_device
98 * Returns the first 32 feature bits (all we currently need).
Rusty Russellc6248962008-07-25 12:06:07 -050099 * @finalize_features: confirm what device features we'll be using.
Rusty Russellc45a6812008-05-02 21:50:50 -0500100 * vdev: the virtio_device
Rusty Russellc6248962008-07-25 12:06:07 -0500101 * This gives the final feature bits for the device: it can change
102 * the dev->feature bits if it wants.
Rusty Russellec3d41c2007-10-22 11:03:36 +1000103 */
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -0600104typedef void vq_callback_t(struct virtqueue *);
Rusty Russell1842f232009-07-30 16:03:46 -0600105struct virtio_config_ops {
Rusty Russella586d4f2008-02-04 23:49:56 -0500106 void (*get)(struct virtio_device *vdev, unsigned offset,
Rusty Russellec3d41c2007-10-22 11:03:36 +1000107 void *buf, unsigned len);
Rusty Russella586d4f2008-02-04 23:49:56 -0500108 void (*set)(struct virtio_device *vdev, unsigned offset,
Rusty Russellec3d41c2007-10-22 11:03:36 +1000109 const void *buf, unsigned len);
110 u8 (*get_status)(struct virtio_device *vdev);
111 void (*set_status)(struct virtio_device *vdev, u8 status);
Rusty Russell6e5aa7e2008-02-04 23:50:03 -0500112 void (*reset)(struct virtio_device *vdev);
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -0600113 int (*find_vqs)(struct virtio_device *, unsigned nvqs,
114 struct virtqueue *vqs[],
115 vq_callback_t *callbacks[],
116 const char *names[]);
117 void (*del_vqs)(struct virtio_device *);
Rusty Russellc45a6812008-05-02 21:50:50 -0500118 u32 (*get_features)(struct virtio_device *vdev);
Rusty Russellc6248962008-07-25 12:06:07 -0500119 void (*finalize_features)(struct virtio_device *vdev);
Rusty Russellec3d41c2007-10-22 11:03:36 +1000120};
121
Rusty Russellc45a6812008-05-02 21:50:50 -0500122/* If driver didn't advertise the feature, it will never appear. */
123void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
124 unsigned int fbit);
125
126/**
127 * virtio_has_feature - helper to determine if this device has this feature.
128 * @vdev: the device
129 * @fbit: the feature bit
130 */
131static inline bool virtio_has_feature(const struct virtio_device *vdev,
132 unsigned int fbit)
133{
134 /* Did you forget to fix assumptions on max features? */
Rusty Russell1765e3a2011-01-24 14:45:10 -0600135 if (__builtin_constant_p(fbit))
136 BUILD_BUG_ON(fbit >= 32);
137 else
138 BUG_ON(fbit >= 32);
Rusty Russellc45a6812008-05-02 21:50:50 -0500139
Mark McLoughlinee006b32009-05-11 18:11:44 +0100140 if (fbit < VIRTIO_TRANSPORT_F_START)
141 virtio_check_driver_offered_feature(vdev, fbit);
142
Rusty Russellc45a6812008-05-02 21:50:50 -0500143 return test_bit(fbit, vdev->features);
144}
145
Rusty Russellec3d41c2007-10-22 11:03:36 +1000146/**
Rusty Russell72e61eb2008-05-02 21:50:49 -0500147 * virtio_config_val - look for a feature and get a virtio config entry.
Rusty Russella586d4f2008-02-04 23:49:56 -0500148 * @vdev: the virtio device
149 * @fbit: the feature bit
150 * @offset: the type to search for.
Rusty Russellec3d41c2007-10-22 11:03:36 +1000151 * @val: a pointer to the value to fill in.
152 *
Rusty Russella586d4f2008-02-04 23:49:56 -0500153 * The return value is -ENOENT if the feature doesn't exist. Otherwise
Rusty Russell72e61eb2008-05-02 21:50:49 -0500154 * the config value is copied into whatever is pointed to by v. */
155#define virtio_config_val(vdev, fbit, offset, v) \
Christian Borntraeger7f31fe02008-05-29 11:08:01 +0200156 virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v))
Rusty Russellec3d41c2007-10-22 11:03:36 +1000157
Rusty Russell72e61eb2008-05-02 21:50:49 -0500158static inline int virtio_config_buf(struct virtio_device *vdev,
159 unsigned int fbit,
160 unsigned int offset,
161 void *buf, unsigned len)
162{
Rusty Russellc45a6812008-05-02 21:50:50 -0500163 if (!virtio_has_feature(vdev, fbit))
Rusty Russell72e61eb2008-05-02 21:50:49 -0500164 return -ENOENT;
165
166 vdev->config->get(vdev, offset, buf, len);
167 return 0;
168}
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -0600169
170static inline
171struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
172 vq_callback_t *c, const char *n)
173{
174 vq_callback_t *callbacks[] = { c };
175 const char *names[] = { n };
176 struct virtqueue *vq;
177 int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
178 if (err < 0)
179 return ERR_PTR(err);
180 return vq;
181}
Rusty Russellec3d41c2007-10-22 11:03:36 +1000182#endif /* __KERNEL__ */
183#endif /* _LINUX_VIRTIO_CONFIG_H */