1 #ifndef _LINUX_VIRTIO_H
2 #define _LINUX_VIRTIO_H
3 /* Everything a virtio driver needs to work with any particular virtio
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>
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.
20 void (*callback
)(struct virtqueue
*vq
);
21 struct virtio_device
*vdev
;
22 struct virtqueue_ops
*vq_ops
;
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.
52 * Locking rules are straightforward: the driver is responsible for
53 * locking. No two operations may be invoked simultaneously, with the exception
56 * All operations can be called in any context.
58 struct virtqueue_ops
{
59 int (*add_buf
)(struct virtqueue
*vq
,
60 struct scatterlist sg
[],
65 void (*kick
)(struct virtqueue
*vq
);
67 void *(*get_buf
)(struct virtqueue
*vq
, unsigned int *len
);
69 void (*disable_cb
)(struct virtqueue
*vq
);
70 bool (*enable_cb
)(struct virtqueue
*vq
);
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.
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];
93 int register_virtio_device(struct virtio_device
*dev
);
94 void unregister_virtio_device(struct virtio_device
*dev
);
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.
108 struct 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
);
118 int register_virtio_driver(struct virtio_driver
*drv
);
119 void unregister_virtio_driver(struct virtio_driver
*drv
);
120 #endif /* _LINUX_VIRTIO_H */
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