device_if.m revision 47178 
1#
2# Copyright (c) 1998 Doug Rabson
3# All rights reserved.
4#
5# Redistribution and use in source and binary forms, with or without
6# modification, are permitted provided that the following conditions
7# are met:
8# 1. Redistributions of source code must retain the above copyright
9#    notice, this list of conditions and the following disclaimer.
10# 2. Redistributions in binary form must reproduce the above copyright
11#    notice, this list of conditions and the following disclaimer in the
12#    documentation and/or other materials provided with the distribution.
13#
14# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24# SUCH DAMAGE.
25#
26#	$Id: device_if.m,v 1.4 1999/05/10 17:06:13 dfr Exp $
27#
28
29INTERFACE device;
30
31#
32# Default implementations of some methods.
33#
34CODE {
35	static int null_shutdown(device_t dev)
36	{
37	    return 0;
38	}
39
40	static int null_suspend(device_t dev)
41	{
42	    return 0;
43	}
44
45	static int null_resume(device_t dev)
46	{
47	    return 0;
48	}
49};
50
51#
52# Probe to see if the device is present.  Return 0 if the device exists,
53# ENXIO if it cannot be found.  For cases where more than one driver
54# matches a device, a priority value can be returned.  In this case,
55# success codes are values less than or equal to zero with the highest 
56# value representing the best match.  Failure codes are represented by
57# positive values and the regular unix error codes should be used for
58# the purpose.
59#
60# If a driver returns a success code which is less than zero, it must
61# not assume that it will be the same driver which is attached to the
62# device. In particular, it must not assume that any values stored in
63# the softc structure will be available for its attach method and any
64# resources allocated during probe must be released and re-allocated
65# if the attach method is called.  If a success code of zero is
66# returned, the driver can assume that it will be the one attached.
67# 
68# Devices which implement busses should use this method to probe for
69# the existence of devices attached to the bus and add them as
70# children.  If this is combined with the use of bus_generic_attach,
71# the child devices will be automatically probed and attached.
72#
73METHOD int probe {
74	device_t dev;
75};
76
77#
78# Called by a parent bus to add new devices to the bus.
79#
80STATICMETHOD void identify {
81	driver_t *driver;
82	device_t parent;
83};
84
85#
86# Attach a device to the system.  The probe method will have been
87# called and will have indicated that the device exists.  This routine
88# should initialise the hardware and allocate other system resources
89# (such as devfs entries).  Returns 0 on success.
90#
91METHOD int attach {
92	device_t dev;
93};
94
95#
96# Detach a device.  This can be called if the user is replacing the
97# driver software or if a device is about to be physically removed
98# from the system (e.g. for pccard devices).  Returns 0 on success.
99#
100METHOD int detach {
101	device_t dev;
102};
103
104#
105# This is called during system shutdown to allow the driver to put the 
106# hardware into a consistent state for rebooting the computer.
107#
108METHOD int shutdown {
109	device_t dev;
110} DEFAULT null_shutdown;
111
112#
113# This is called by the power-management subsystem when a suspend has been
114# requested by the user or by some automatic mechanism.  This gives
115# drivers a chance to veto the suspend or save their configuration before
116# power is removed.
117#
118METHOD int suspend {
119	device_t dev;
120} DEFAULT null_suspend;
121
122METHOD int resume {
123	device_t dev;
124} DEFAULT null_resume;
125