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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>
Michael S. Tsirkinbbd603e2010-04-29 17:26:37 +030010#include <linux/gfp.h>
Rusty Russellec3d41c2007-10-22 11:03:36 +100011
12/**
13 * virtqueue - a queue to register buffers for sending or receiving.
Rusty Russell9499f5e2009-06-12 22:16:35 -060014 * @list: the chain of virtqueues for this device
Rusty Russellec3d41c2007-10-22 11:03:36 +100015 * @callback: the function to call when buffers are consumed (can be NULL).
Rusty Russell9499f5e2009-06-12 22:16:35 -060016 * @name: the name of this virtqueue (mainly for debugging)
Rusty Russellec3d41c2007-10-22 11:03:36 +100017 * @vdev: the virtio device this queue was created for.
Rusty Russellec3d41c2007-10-22 11:03:36 +100018 * @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;
Rusty Russellec3d41c2007-10-22 11:03:36 +100025 void *priv;
26};
27
28/**
Michael S. Tsirkin7c5e9ed2010-04-12 16:19:07 +030029 * operations for virtqueue
30 * virtqueue_add_buf: expose buffer to other end
Rusty Russellec3d41c2007-10-22 11:03:36 +100031 * vq: the struct virtqueue we're talking about.
32 * sg: the description of the buffer(s).
33 * out_num: the number of sg readable by other side
34 * in_num: the number of sg which are writable (after readable ones)
35 * data: the token identifying the buffer.
Michael S. Tsirkinbbd603e2010-04-29 17:26:37 +030036 * gfp: how to do memory allocations (if necessary).
Rusty Russell3c1b27d2009-09-23 22:26:31 -060037 * Returns remaining capacity of queue (sg segments) or a negative error.
Michael S. Tsirkin7c5e9ed2010-04-12 16:19:07 +030038 * virtqueue_kick: update after add_buf
Rusty Russellec3d41c2007-10-22 11:03:36 +100039 * vq: the struct virtqueue
40 * After one or more add_buf calls, invoke this to kick the other side.
Michael S. Tsirkin7c5e9ed2010-04-12 16:19:07 +030041 * virtqueue_get_buf: get the next used buffer
Rusty Russellec3d41c2007-10-22 11:03:36 +100042 * 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.
Michael S. Tsirkin7c5e9ed2010-04-12 16:19:07 +030045 * virtqueue_disable_cb: disable callbacks
Rusty Russell18445c42008-02-04 23:49:57 -050046 * 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.
Michael S. Tsirkin7c5e9ed2010-04-12 16:19:07 +030049 * virtqueue_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.
Michael S. Tsirkin7ab358c2011-05-20 02:11:14 +030054 * virtqueue_enable_cb_delayed: restart callbacks after disable_cb.
55 * vq: the struct virtqueue we're talking about.
56 * This re-enables callbacks but hints to the other side to delay
57 * interrupts until most of the available buffers have been processed;
58 * it returns "false" if there are many pending buffers in the queue,
59 * to detect a possible race between the driver checking for more work,
60 * and enabling callbacks.
Michael S. Tsirkin7c5e9ed2010-04-12 16:19:07 +030061 * virtqueue_detach_unused_buf: detach first unused buffer
Shirley Mac021eac2010-01-18 19:15:23 +053062 * vq: the struct virtqueue we're talking about.
63 * Returns NULL or the "data" token handed to add_buf
Rusty Russellec3d41c2007-10-22 11:03:36 +100064 *
65 * Locking rules are straightforward: the driver is responsible for
Rusty Russell2557a932008-04-07 14:30:28 +100066 * locking. No two operations may be invoked simultaneously, with the exception
Michael S. Tsirkin7c5e9ed2010-04-12 16:19:07 +030067 * of virtqueue_disable_cb.
Rusty Russellec3d41c2007-10-22 11:03:36 +100068 *
69 * All operations can be called in any context.
70 */
Rusty Russellec3d41c2007-10-22 11:03:36 +100071
Michael S. Tsirkinbbd603e2010-04-29 17:26:37 +030072int virtqueue_add_buf_gfp(struct virtqueue *vq,
73 struct scatterlist sg[],
74 unsigned int out_num,
75 unsigned int in_num,
76 void *data,
77 gfp_t gfp);
78
79static inline int virtqueue_add_buf(struct virtqueue *vq,
80 struct scatterlist sg[],
81 unsigned int out_num,
82 unsigned int in_num,
83 void *data)
84{
85 return virtqueue_add_buf_gfp(vq, sg, out_num, in_num, data, GFP_ATOMIC);
86}
Rusty Russellec3d41c2007-10-22 11:03:36 +100087
Michael S. Tsirkin7c5e9ed2010-04-12 16:19:07 +030088void virtqueue_kick(struct virtqueue *vq);
Rusty Russellec3d41c2007-10-22 11:03:36 +100089
Michael S. Tsirkin7c5e9ed2010-04-12 16:19:07 +030090void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
Rusty Russellec3d41c2007-10-22 11:03:36 +100091
Michael S. Tsirkin7c5e9ed2010-04-12 16:19:07 +030092void virtqueue_disable_cb(struct virtqueue *vq);
Michael S. Tsirkin316f25f2010-04-12 16:18:25 +030093
Michael S. Tsirkin7c5e9ed2010-04-12 16:19:07 +030094bool virtqueue_enable_cb(struct virtqueue *vq);
Michael S. Tsirkin316f25f2010-04-12 16:18:25 +030095
Michael S. Tsirkin7ab358c2011-05-20 02:11:14 +030096bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
97
Michael S. Tsirkin7c5e9ed2010-04-12 16:19:07 +030098void *virtqueue_detach_unused_buf(struct virtqueue *vq);
Michael S. Tsirkin316f25f2010-04-12 16:18:25 +030099
Rusty Russellec3d41c2007-10-22 11:03:36 +1000100/**
101 * virtio_device - representation of a device using virtio
102 * @index: unique position on the virtio bus
103 * @dev: underlying device.
104 * @id: the device type identification (used to match it with a driver).
105 * @config: the configuration ops for this device.
Rusty Russell9499f5e2009-06-12 22:16:35 -0600106 * @vqs: the list of virtqueues for this device.
Rusty Russellc45a6812008-05-02 21:50:50 -0500107 * @features: the features supported by both driver and device.
Rusty Russellec3d41c2007-10-22 11:03:36 +1000108 * @priv: private pointer for the driver's use.
109 */
Rusty Russell9499f5e2009-06-12 22:16:35 -0600110struct virtio_device {
Rusty Russellec3d41c2007-10-22 11:03:36 +1000111 int index;
112 struct device dev;
113 struct virtio_device_id id;
114 struct virtio_config_ops *config;
Rusty Russell9499f5e2009-06-12 22:16:35 -0600115 struct list_head vqs;
Rusty Russellc45a6812008-05-02 21:50:50 -0500116 /* Note that this is a Linux set_bit-style bitmap. */
117 unsigned long features[1];
Rusty Russellec3d41c2007-10-22 11:03:36 +1000118 void *priv;
119};
120
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000121#define dev_to_virtio(dev) container_of(dev, struct virtio_device, dev)
Rusty Russellec3d41c2007-10-22 11:03:36 +1000122int register_virtio_device(struct virtio_device *dev);
123void unregister_virtio_device(struct virtio_device *dev);
124
125/**
126 * virtio_driver - operations for a virtio I/O driver
127 * @driver: underlying device driver (populate name and owner).
128 * @id_table: the ids serviced by this driver.
Rusty Russellc45a6812008-05-02 21:50:50 -0500129 * @feature_table: an array of feature numbers supported by this device.
130 * @feature_table_size: number of entries in the feature table array.
Rusty Russell20f77f52009-06-12 22:16:33 -0600131 * @probe: the function to call when a device is found. Returns 0 or -errno.
Rusty Russellec3d41c2007-10-22 11:03:36 +1000132 * @remove: the function when a device is removed.
Rusty Russellf957d1f2008-02-04 23:49:58 -0500133 * @config_changed: optional function to call when the device configuration
134 * changes; may be called in interrupt context.
Rusty Russellec3d41c2007-10-22 11:03:36 +1000135 */
136struct virtio_driver {
137 struct device_driver driver;
138 const struct virtio_device_id *id_table;
Rusty Russellc45a6812008-05-02 21:50:50 -0500139 const unsigned int *feature_table;
140 unsigned int feature_table_size;
Rusty Russellec3d41c2007-10-22 11:03:36 +1000141 int (*probe)(struct virtio_device *dev);
142 void (*remove)(struct virtio_device *dev);
Rusty Russellf957d1f2008-02-04 23:49:58 -0500143 void (*config_changed)(struct virtio_device *dev);
Rusty Russellec3d41c2007-10-22 11:03:36 +1000144};
145
146int register_virtio_driver(struct virtio_driver *drv);
147void unregister_virtio_driver(struct virtio_driver *drv);
148#endif /* _LINUX_VIRTIO_H */