device_if.m revision 47984 
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 1.5 1999/05/14 11:22:41 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. If some other error happens during the
54# probe (such as a memory allocation failure), an appropriate error code
55# should be returned. For cases where more than one driver matches a
56# device, a priority value can be returned.  In this case, success codes
57# are values less than or equal to zero with the highest value representing
58# the best match.  Failure codes are represented by positive values and
59# the regular unix error codes should be used for the purpose.
60
61# If a driver returns a success code which is less than zero, it must
62# not assume that it will be the same driver which is attached to the
63# device. In particular, it must not assume that any values stored in
64# the softc structure will be available for its attach method and any
65# resources allocated during probe must be released and re-allocated
66# if the attach method is called.  If a success code of zero is
67# returned, the driver can assume that it will be the one attached.
68# 
69# Devices which implement busses should use this method to probe for
70# the existence of devices attached to the bus and add them as
71# children.  If this is combined with the use of bus_generic_attach,
72# the child devices will be automatically probed and attached.
73#
74METHOD int probe {
75	device_t dev;
76};
77
78#
79# Called by a parent bus to add new devices to the bus.
80#
81STATICMETHOD void identify {
82	driver_t *driver;
83	device_t parent;
84};
85
86#
87# Attach a device to the system.  The probe method will have been
88# called and will have indicated that the device exists.  This routine
89# should initialise the hardware and allocate other system resources
90# (such as devfs entries).  Returns 0 on success.
91#
92METHOD int attach {
93	device_t dev;
94};
95
96#
97# Detach a device.  This can be called if the user is replacing the
98# driver software or if a device is about to be physically removed
99# from the system (e.g. for pccard devices).  Returns 0 on success.
100#
101METHOD int detach {
102	device_t dev;
103};
104
105#
106# This is called during system shutdown to allow the driver to put the 
107# hardware into a consistent state for rebooting the computer.
108#
109METHOD int shutdown {
110	device_t dev;
111} DEFAULT null_shutdown;
112
113#
114# This is called by the power-management subsystem when a suspend has been
115# requested by the user or by some automatic mechanism.  This gives
116# drivers a chance to veto the suspend or save their configuration before
117# power is removed.
118#
119METHOD int suspend {
120	device_t dev;
121} DEFAULT null_suspend;
122
123METHOD int resume {
124	device_t dev;
125} DEFAULT null_resume;
126