xref: /netbsd-src/share/man/man4/man4.sparc/openprom.4 (revision ce0bb6e8d2e560ecacbe865a848624f94498063b)
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36.\"     from: @(#)openprom.4	8.1 (Berkeley) 6/5/93
37.\"	$Id: openprom.4,v 1.1 1994/07/01 20:47:56 deraadt Exp $
38.\"
39.Dd June 5, 1993
40.Dt OPENPROM 4 sparc
41.Os
42.Sh NAME
43.Nm openprom
44.Nd OPENPROM and EEPROM interface
45.Sh SYNOPSIS
46.Fd #include <machine/openpromio.h>
47.Sh DESCRIPTION
48The file
49.Nm /dev/openprom
50is an interface to the SPARC OPENPROM,
51including the EEPROM area.
52This interface is highly stylized;
53ioctls are used for all operations.
54These ioctls refer to
55.Dq nodes ,
56which are simply
57.Dq magic
58integer values describing data areas.
59Occasionally the number 0 may be used or returned instead,
60as described below.
61A special distinguished
62.Dq options
63node holds the EEPROM settings.
64.Pp
65The calls that take and/or return a node
66use a pointer to an
67.Li int
68variable for this purpose;
69others use a pointer to an
70.Li struct opiocdesc
71descriptor,
72which contains a node and two counted strings.
73The first string is comprised of the fields
74.Li op_namelen
75(an
76.Li int )
77and
78.Li op_name
79(a
80.Li "char *" ) ,
81giving the name of a field.
82The second string is comprised of the fields
83.Li op_buflen
84and
85.Li op_buf ,
86used analogously.
87These two counted strings work in a
88.Dq value-result
89fashion.
90At entry to the ioctl,
91the counts are expected to reflect the buffer size;
92on return,
93the counts are updated to reflect the buffer contents.
94.Pp
95The following ioctls are supported:
96.Bl -tag -width OPIOCGETOPTNODE
97.It Dv OPIOCGETOPTNODE
98Takes nothing, and fills in the options node number.
99.It OPIOCGETNEXT
100Takes a node number and returns the number of the following node.
101The node following the last node is number 0;
102the node following number 0 is the first node.
103.It Dv OPIOCGETCHILD
104Takes a node number and returns the number of the first
105.Dq child
106of that node.
107This child may have siblings; these can be discovered by using
108.Dv OPIOCGETNEXT .
109.It Dv OPIOCGET
110Fills in the value of the named property for the given node.
111If no such property is associated with that node,
112the value length is set to -1.
113If the named property exists but has no value,
114the value length is set to 0.
115.It Dv OPIOCSET
116Writes the given value under the given name.
117The OPENPROM may refuse this operation;
118in this case
119.Dv EINVAL
120is returned.
121.It Dv OPIOCNEXTPROP
122Finds the property whose name follows the given name
123in OPENPROM internal order.
124The resulting name is returned in the value field.
125If the named property is the last, the
126.Dq next
127name is the empty string.
128As with
129.Dv OPIOCGETNEXT ,
130the next name after the empty string is the first name.
131.El
132.Sh FILES
133.Pa /dev/openprom
134.Sh ERRORS
135The following may result in rejection of an operation:
136.Bl -tag -width Er
137.It Bq Er EINVAL
138The given node number
139is not zero
140and does not correspond to any valid node,
141or is zero where zero is not allowed.
142.It Bq Er EBADF
143The requested operation requires permissions not specified at the call to
144.Fn open .
145.It Bq Er ENAMETOOLONG
146The given name or value field
147exceeds the maximum allowed length (8191 bytes).
148.El
149.Sh SEE ALSO
150.Xr ioctl 2
151.Sh BUGS
152Due to limitations within the OPENPROM itself,
153these functions run at elevated priority
154and may adversely affect system performance.
155