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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.
13 * @callback: the function to call when buffers are consumed (can be NULL).
Rusty Russellec3d41c2007-10-22 11:03:36 +100014 * @vdev: the virtio device this queue was created for.
15 * @vq_ops: the operations for this virtqueue (see below).
16 * @priv: a pointer for the virtqueue implementation to use.
17 */
18struct virtqueue
19{
Rusty Russell18445c42008-02-04 23:49:57 -050020 void (*callback)(struct virtqueue *vq);
Rusty Russellec3d41c2007-10-22 11:03:36 +100021 struct virtio_device *vdev;
22 struct virtqueue_ops *vq_ops;
23 void *priv;
24};
25
26/**
27 * virtqueue_ops - operations for virtqueue abstraction layer
28 * @add_buf: expose buffer to other end
29 * vq: the struct virtqueue we're talking about.
30 * sg: the description of the buffer(s).
31 * out_num: the number of sg readable by other side
32 * in_num: the number of sg which are writable (after readable ones)
33 * data: the token identifying the buffer.
34 * Returns 0 or an error.
35 * @kick: update after add_buf
36 * vq: the struct virtqueue
37 * After one or more add_buf calls, invoke this to kick the other side.
38 * @get_buf: get the next used buffer
39 * vq: the struct virtqueue we're talking about.
40 * len: the length written into the buffer
41 * Returns NULL or the "data" token handed to add_buf.
Rusty Russell18445c42008-02-04 23:49:57 -050042 * @disable_cb: disable callbacks
43 * vq: the struct virtqueue we're talking about.
Rusty Russell2557a932008-04-07 14:30:28 +100044 * Note that this is not necessarily synchronous, hence unreliable and only
45 * useful as an optimization.
Rusty Russell18445c42008-02-04 23:49:57 -050046 * @enable_cb: restart callbacks after disable_cb.
Rusty Russellec3d41c2007-10-22 11:03:36 +100047 * vq: the struct virtqueue we're talking about.
Christian Borntraeger4265f162008-03-14 14:17:05 +010048 * This re-enables callbacks; it returns "false" if there are pending
49 * buffers in the queue, to detect a possible race between the driver
50 * checking for more work, and enabling callbacks.
Rusty Russellec3d41c2007-10-22 11:03:36 +100051 *
52 * Locking rules are straightforward: the driver is responsible for
Rusty Russell2557a932008-04-07 14:30:28 +100053 * locking. No two operations may be invoked simultaneously, with the exception
54 * of @disable_cb.
Rusty Russellec3d41c2007-10-22 11:03:36 +100055 *
56 * All operations can be called in any context.
57 */
58struct virtqueue_ops {
59 int (*add_buf)(struct virtqueue *vq,
60 struct scatterlist sg[],
61 unsigned int out_num,
62 unsigned int in_num,
63 void *data);
64
65 void (*kick)(struct virtqueue *vq);
66
67 void *(*get_buf)(struct virtqueue *vq, unsigned int *len);
68
Rusty Russell18445c42008-02-04 23:49:57 -050069 void (*disable_cb)(struct virtqueue *vq);
70 bool (*enable_cb)(struct virtqueue *vq);
Rusty Russellec3d41c2007-10-22 11:03:36 +100071};
72
73/**
74 * virtio_device - representation of a device using virtio
75 * @index: unique position on the virtio bus
76 * @dev: underlying device.
77 * @id: the device type identification (used to match it with a driver).
78 * @config: the configuration ops for this device.
79 * @priv: private pointer for the driver's use.
80 */
81struct virtio_device
82{
83 int index;
84 struct device dev;
85 struct virtio_device_id id;
86 struct virtio_config_ops *config;
87 void *priv;
88};
89
90int register_virtio_device(struct virtio_device *dev);
91void unregister_virtio_device(struct virtio_device *dev);
92
93/**
94 * virtio_driver - operations for a virtio I/O driver
95 * @driver: underlying device driver (populate name and owner).
96 * @id_table: the ids serviced by this driver.
97 * @probe: the function to call when a device is found. Returns a token for
98 * remove, or PTR_ERR().
99 * @remove: the function when a device is removed.
Rusty Russellf957d1f2008-02-04 23:49:58 -0500100 * @config_changed: optional function to call when the device configuration
101 * changes; may be called in interrupt context.
Rusty Russellec3d41c2007-10-22 11:03:36 +1000102 */
103struct virtio_driver {
104 struct device_driver driver;
105 const struct virtio_device_id *id_table;
106 int (*probe)(struct virtio_device *dev);
107 void (*remove)(struct virtio_device *dev);
Rusty Russellf957d1f2008-02-04 23:49:58 -0500108 void (*config_changed)(struct virtio_device *dev);
Rusty Russellec3d41c2007-10-22 11:03:36 +1000109};
110
111int register_virtio_driver(struct virtio_driver *drv);
112void unregister_virtio_driver(struct virtio_driver *drv);
113#endif /* _LINUX_VIRTIO_H */