OPENPROM(4)           OpenBSD Programmer's Manual (SPARC)          OPENPROM(4)

NAME
     openprom - OPENPROM and EEPROM interface

SYNOPSIS
     #include <machine/openpromio.h>

DESCRIPTION
     The file /dev/openprom is an interface to the SPARC OPENPROM, including
     the EEPROM area.  This interface is highly stylized; ioctls are used for
     all operations.  These ioctls refer to ``nodes'', which are simply
     ``magic'' integer values describing data areas.  Occasionally the number
     0 may be used or returned instead, as described below.  A special distin-
     guished ``options'' node holds the EEPROM settings.

     The calls that take and/or return a node use a pointer to an int variable
     for this purpose; others use a pointer to an struct opiocdesc descriptor,
     which contains a node and two counted strings.  The first string is com-
     prised of the fields op_namelen (an int) and op_name (a char *), giving
     the name of a field.  The second string is comprised of the fields
     op_buflen and op_buf, used analogously.  These two counted strings work
     in a ``value-result'' fashion.  At entry to the ioctl, the counts are ex-
     pected to reflect the buffer size; on return, the counts are updated to
     reflect the buffer contents.

     The following ioctls are supported:

     OPIOCGETOPTNODE  Takes nothing, and fills in the options node number.

     OPIOCGETNEXT     Takes a node number and returns the number of the fol-
                      lowing node.  The node following the last node is number
                      0; the node following number 0 is the first node.

     OPIOCGETCHILD    Takes a node number and returns the number of the first
                      ``child'' of that node.  This child may have siblings;
                      these can be discovered by using OPIOCGETNEXT.

     OPIOCGET         Fills in the value of the named property for the given
                      node.  If no such property is associated with that node,
                      the value length is set to -1.  If the named property
                      exists but has no value, the value length is set to 0.

     OPIOCSET         Writes the given value under the given name.  The OPEN-
                      PROM may refuse this operation; in this case EINVAL is
                      returned.

     OPIOCNEXTPROP    Finds the property whose name follows the given name in
                      OPENPROM internal order.  The resulting name is returned
                      in the value field.  If the named property is the last,
                      the ``next'' name is the empty string.  As with
                      OPIOCGETNEXT, the next name after the empty string is
                      the first name.

FILES
     /dev/openprom

ERRORS
     The following may result in rejection of an operation:

     [EINVAL]      The given node number is not zero and does not correspond
                   to any valid node, or is zero where zero is not allowed.

     [EBADF]       The requested operation requires permissions not specified

                   at the call to open().

     [ENAMETOOLONG]
                   The given name or value field exceeds the maximum allowed
                   length (8191 bytes).

SEE ALSO
     ioctl(2)

BUGS
     Due to limitations within the OPENPROM itself, these functions run at el-
     evated priority and may adversely affect system performance.

OpenBSD 3.0                      June 5, 1993                                2
