OPENPROM(4S)

NAME
openprom - PROM monitor configuration interface

CONFIG
pseudo-device openeepr

SYNOPSIS
#include <fcntl.h>
#include <sys/types.h>
#include <sundev/openpromio.h>
open("/dev/openprom", mode);

AVAILABILITY

Desktop SPARCsystems and SPARCsystem 600MP Series only.

DESCRIPTION

As with other Sun systems, configuration options are stored in an EEPROM or NVRAM on desktop SPARCsystems and SPARCsystem 600MP series machines. However, unlike other Sun systems, the encoding of these options is private to the PROM monitor. The openprom device provides an interface to the PROM monitor allowing a user program to query and set these configuration options through the use of ioctl(2) requests. These requests are defined in <sundev/openpromio.h>:

    struct openpromio {
            u_int   oprom_size;			/* real size of following array */
            char    oprom_array[1];		/* For property names and values */
    					/* NB: Adjacent, Null terminated */
    };
    #define OPROMMAXPARAM   1024	/* max size of array */
    /*
     * Note that all OPROM ioctl codes are type void. Since the amount
     * of data copied in/out may (and does) vary, the openprom driver
     * handles the copyin/copyout itself.
     */
    #define OPROMGETOPT
        _IO(O, 1)
    #define OPROMNXTOPT
        _IO(O, 3)
    #define OPROMSETOPT2
        _IO(O, 4)
For all ioctl() requests, the third parameter is a pointer to a `struct openpromio'. All property names and values are null-terminated strings; the value of a numeric option is its ASCII representation.

IOCTLS
The OPROMGETOPT ioctl takes the null-terminated name of a property in the oprom_array and returns its null-terminated value (overlaying its name). oprom_size should be set to the size of oprom_array; on return it will contain the size of the returned value. If the named property does not exist, or if there is not enough space to hold its value, then oprom_size will be set to zero. See BUGS below.
The OPROMSETOPT2 ioctl takes two adjacent strings in oprom_array: the null-terminated property name followed by the null-terminated value.
The OPROMNXTOPT ioctl is used to retrieve properties sequentially. The null-terminated name of a property is placed into oprom_array and on return it is replaced with the null-terminated name of the next property in the sequence, with oprom_size set to its length. A null string on input means return the name of the first property; an oprom_size of zero on output means there are no more properties.

ERRORS
EINVAL
    The size value was invalid, or (for OPROMSETOPT) the property does not exist.
ENOMEM
    The kernel could not allocate space to copy the user's structure

FILES
/dev/openprom
    PROM monitor configuration interface

SEE ALSO
mem(4S), eeprom(8S), monitor(8S), openboot(8S)

BUGS
There should be separate return values for non-existent properties as opposed to not enough space for the value.
The driver should be more consistent in its treatment of errors and edge conditions.