Linux kernel mirror (for testing)
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linux
1#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).
14 * @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{
20 void (*callback)(struct virtqueue *vq);
21 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.
42 * @disable_cb: disable callbacks
43 * vq: the struct virtqueue we're talking about.
44 * Note that this is not necessarily synchronous, hence unreliable and only
45 * useful as an optimization.
46 * @enable_cb: restart callbacks after disable_cb.
47 * vq: the struct virtqueue we're talking about.
48 * 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.
51 *
52 * Locking rules are straightforward: the driver is responsible for
53 * locking. No two operations may be invoked simultaneously, with the exception
54 * of @disable_cb.
55 *
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
69 void (*disable_cb)(struct virtqueue *vq);
70 bool (*enable_cb)(struct virtqueue *vq);
71};
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 * @features: the features supported by both driver and device.
80 * @priv: private pointer for the driver's use.
81 */
82struct virtio_device
83{
84 int index;
85 struct device dev;
86 struct virtio_device_id id;
87 struct virtio_config_ops *config;
88 /* Note that this is a Linux set_bit-style bitmap. */
89 unsigned long features[1];
90 void *priv;
91};
92
93int register_virtio_device(struct virtio_device *dev);
94void unregister_virtio_device(struct virtio_device *dev);
95
96/**
97 * virtio_driver - operations for a virtio I/O driver
98 * @driver: underlying device driver (populate name and owner).
99 * @id_table: the ids serviced by this driver.
100 * @feature_table: an array of feature numbers supported by this device.
101 * @feature_table_size: number of entries in the feature table array.
102 * @probe: the function to call when a device is found. Returns a token for
103 * remove, or PTR_ERR().
104 * @remove: the function when a device is removed.
105 * @config_changed: optional function to call when the device configuration
106 * changes; may be called in interrupt context.
107 */
108struct virtio_driver {
109 struct device_driver driver;
110 const struct virtio_device_id *id_table;
111 const unsigned int *feature_table;
112 unsigned int feature_table_size;
113 int (*probe)(struct virtio_device *dev);
114 void (*remove)(struct virtio_device *dev);
115 void (*config_changed)(struct virtio_device *dev);
116};
117
118int register_virtio_driver(struct virtio_driver *drv);
119void unregister_virtio_driver(struct virtio_driver *drv);
120#endif /* _LINUX_VIRTIO_H */