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Rusty Russellec3d41c2007-10-22 11:03:36 +10001#ifndef _LINUX_VIRTIO_H
2#define _LINUX_VIRTIO_H
3/* Everything a virtio driver needs to work with any particular virtio
4 * implementation. */
5#include <linux/types.h>
6#include <linux/scatterlist.h>
7#include <linux/spinlock.h>
8#include <linux/device.h>
9#include <linux/mod_devicetable.h>
10
11/**
12 * virtqueue - a queue to register buffers for sending or receiving.
Rusty Russell9499f5e2009-06-12 22:16:35 -060013 * @list: the chain of virtqueues for this device
Rusty Russellec3d41c2007-10-22 11:03:36 +100014 * @callback: the function to call when buffers are consumed (can be NULL).
Rusty Russell9499f5e2009-06-12 22:16:35 -060015 * @name: the name of this virtqueue (mainly for debugging)
Rusty Russellec3d41c2007-10-22 11:03:36 +100016 * @vdev: the virtio device this queue was created for.
17 * @vq_ops: the operations for this virtqueue (see below).
18 * @priv: a pointer for the virtqueue implementation to use.
19 */
Rusty Russell9499f5e2009-06-12 22:16:35 -060020struct virtqueue {
21 struct list_head list;
Rusty Russell18445c42008-02-04 23:49:57 -050022 void (*callback)(struct virtqueue *vq);
Rusty Russell9499f5e2009-06-12 22:16:35 -060023 const char *name;
Rusty Russellec3d41c2007-10-22 11:03:36 +100024 struct virtio_device *vdev;
25 struct virtqueue_ops *vq_ops;
26 void *priv;
27};
28
29/**
30 * virtqueue_ops - operations for virtqueue abstraction layer
31 * @add_buf: expose buffer to other end
32 * vq: the struct virtqueue we're talking about.
33 * sg: the description of the buffer(s).
34 * out_num: the number of sg readable by other side
35 * in_num: the number of sg which are writable (after readable ones)
36 * data: the token identifying the buffer.
Rusty Russell3c1b27d2009-09-23 22:26:31 -060037 * Returns remaining capacity of queue (sg segments) or a negative error.
Rusty Russellec3d41c2007-10-22 11:03:36 +100038 * @kick: update after add_buf
39 * vq: the struct virtqueue
40 * After one or more add_buf calls, invoke this to kick the other side.
41 * @get_buf: get the next used buffer
42 * vq: the struct virtqueue we're talking about.
43 * len: the length written into the buffer
44 * Returns NULL or the "data" token handed to add_buf.
Rusty Russell18445c42008-02-04 23:49:57 -050045 * @disable_cb: disable callbacks
46 * vq: the struct virtqueue we're talking about.
Rusty Russell2557a932008-04-07 14:30:28 +100047 * Note that this is not necessarily synchronous, hence unreliable and only
48 * useful as an optimization.
Rusty Russell18445c42008-02-04 23:49:57 -050049 * @enable_cb: restart callbacks after disable_cb.
Rusty Russellec3d41c2007-10-22 11:03:36 +100050 * vq: the struct virtqueue we're talking about.
Christian Borntraeger4265f162008-03-14 14:17:05 +010051 * This re-enables callbacks; it returns "false" if there are pending
52 * buffers in the queue, to detect a possible race between the driver
53 * checking for more work, and enabling callbacks.
Rusty Russellec3d41c2007-10-22 11:03:36 +100054 *
55 * Locking rules are straightforward: the driver is responsible for
Rusty Russell2557a932008-04-07 14:30:28 +100056 * locking. No two operations may be invoked simultaneously, with the exception
57 * of @disable_cb.
Rusty Russellec3d41c2007-10-22 11:03:36 +100058 *
59 * All operations can be called in any context.
60 */
61struct virtqueue_ops {
62 int (*add_buf)(struct virtqueue *vq,
63 struct scatterlist sg[],
64 unsigned int out_num,
65 unsigned int in_num,
66 void *data);
67
68 void (*kick)(struct virtqueue *vq);
69
70 void *(*get_buf)(struct virtqueue *vq, unsigned int *len);
71
Rusty Russell18445c42008-02-04 23:49:57 -050072 void (*disable_cb)(struct virtqueue *vq);
73 bool (*enable_cb)(struct virtqueue *vq);
Rusty Russellec3d41c2007-10-22 11:03:36 +100074};
75
76/**
77 * virtio_device - representation of a device using virtio
78 * @index: unique position on the virtio bus
79 * @dev: underlying device.
80 * @id: the device type identification (used to match it with a driver).
81 * @config: the configuration ops for this device.
Rusty Russell9499f5e2009-06-12 22:16:35 -060082 * @vqs: the list of virtqueues for this device.
Rusty Russellc45a6812008-05-02 21:50:50 -050083 * @features: the features supported by both driver and device.
Rusty Russellec3d41c2007-10-22 11:03:36 +100084 * @priv: private pointer for the driver's use.
85 */
Rusty Russell9499f5e2009-06-12 22:16:35 -060086struct virtio_device {
Rusty Russellec3d41c2007-10-22 11:03:36 +100087 int index;
88 struct device dev;
89 struct virtio_device_id id;
90 struct virtio_config_ops *config;
Rusty Russell9499f5e2009-06-12 22:16:35 -060091 struct list_head vqs;
Rusty Russellc45a6812008-05-02 21:50:50 -050092 /* Note that this is a Linux set_bit-style bitmap. */
93 unsigned long features[1];
Rusty Russellec3d41c2007-10-22 11:03:36 +100094 void *priv;
95};
96
97int register_virtio_device(struct virtio_device *dev);
98void unregister_virtio_device(struct virtio_device *dev);
99
100/**
101 * virtio_driver - operations for a virtio I/O driver
102 * @driver: underlying device driver (populate name and owner).
103 * @id_table: the ids serviced by this driver.
Rusty Russellc45a6812008-05-02 21:50:50 -0500104 * @feature_table: an array of feature numbers supported by this device.
105 * @feature_table_size: number of entries in the feature table array.
Rusty Russell20f77f52009-06-12 22:16:33 -0600106 * @probe: the function to call when a device is found. Returns 0 or -errno.
Rusty Russellec3d41c2007-10-22 11:03:36 +1000107 * @remove: the function when a device is removed.
Rusty Russellf957d1f2008-02-04 23:49:58 -0500108 * @config_changed: optional function to call when the device configuration
109 * changes; may be called in interrupt context.
Rusty Russellec3d41c2007-10-22 11:03:36 +1000110 */
111struct virtio_driver {
112 struct device_driver driver;
113 const struct virtio_device_id *id_table;
Rusty Russellc45a6812008-05-02 21:50:50 -0500114 const unsigned int *feature_table;
115 unsigned int feature_table_size;
Rusty Russellec3d41c2007-10-22 11:03:36 +1000116 int (*probe)(struct virtio_device *dev);
117 void (*remove)(struct virtio_device *dev);
Rusty Russellf957d1f2008-02-04 23:49:58 -0500118 void (*config_changed)(struct virtio_device *dev);
Rusty Russellec3d41c2007-10-22 11:03:36 +1000119};
120
121int register_virtio_driver(struct virtio_driver *drv);
122void unregister_virtio_driver(struct virtio_driver *drv);
123#endif /* _LINUX_VIRTIO_H */