1/*****************************************************************************
2 * xenbus.h
3 *
4 * Xenbus protocol details.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to
8 * deal in the Software without restriction, including without limitation the
9 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22 * DEALINGS IN THE SOFTWARE.
23 *
24 * Copyright (C) 2005 XenSource Ltd.
25 */
26
27#ifndef _XEN_PUBLIC_IO_XENBUS_H
28#define _XEN_PUBLIC_IO_XENBUS_H
29
30/*
31 * The state of either end of the Xenbus, i.e. the current communication
32 * status of initialisation across the bus.  States here imply nothing about
33 * the state of the connection between the driver and the kernel's device
34 * layers.
35 */
36enum xenbus_state {
37    XenbusStateUnknown       = 0,
38
39    /*
40     * Initializing: Back-end is initializing.
41     */
42    XenbusStateInitialising  = 1,
43
44    /*
45     * InitWait: Finished early initialisation but waiting for information
46     * from the peer or hotplug scripts.
47     */
48    XenbusStateInitWait      = 2,
49
50    /*
51     * Initialised: Waiting for a connection from the peer.
52     */
53    XenbusStateInitialised   = 3,
54
55    /*
56     * Connected: The normal state for a front to backend connection.
57     */
58    XenbusStateConnected     = 4,
59
60    /*
61     * Closing: The device is being closed due to an error or an unplug event.
62     */
63    XenbusStateClosing       = 5,
64
65    /*
66     * Closed: No connection exists between front and back end.
67     *
68     * For backend devices with the "online" attribute, the front can
69     * request a reconnect at any time.  To handle this transition
70     * gracefully, backend devices must reinitialize any XenStore data
71     * used to negotiate features with a peer before transitioning to
72     * the closed state.  When a reconnect request occurs, the
73     * XenBus backend support code will automatically transition the
74     * backend device from Closed to InitWait, kicking off the ring
75     * and feature negotiation process.
76     */
77    XenbusStateClosed        = 6,
78
79    /*
80     * Reconfiguring: The device is being reconfigured.
81     */
82    XenbusStateReconfiguring = 7,
83
84    XenbusStateReconfigured  = 8
85};
86typedef enum xenbus_state XenbusState;
87
88#endif /* _XEN_PUBLIC_IO_XENBUS_H */
89
90/*
91 * Local variables:
92 * mode: C
93 * c-set-style: "BSD"
94 * c-basic-offset: 4
95 * tab-width: 4
96 * indent-tabs-mode: nil
97 * End:
98 */
99