Date: Wed, 1 Mar 1995 10:08:03 -0700
From: ron@apple.com (Ron Hochsprung)
Subject: Item #239: PowerPC binding - Locating Standard Devices

P1275 Open Firmware Working Group Proposal -- Proposal #239 Ver <Auth-Vers#>

Title:          locating standard devices

Author:         Ron Hochsprung

Date:           March 1, 1995

Ed/Tech:        Technical

Synopsis:       add properties and/or aliases to locate standard devices

Doc & Version:  PowerPC binding

Problem:
We have defined several standard devices (e.g., RTC, NVRAM) along with
their behavior.  In many cases, the methods for them are not necessarily in
the context of a normal device (e.g., OPEN, CLOSE).  If a Client Program
wants to use such devices (e.g., RTC) there is no generic way to locate the
device node (i.e., come up with an IHANDLE) in order to do a CALL-METHOD.

Proposal:

For each device that needs to be accessable to Client Programs, provide a
standard property within the /CHOSEN node that contains an IHANDLE that can
be used by CALL-METHOD client calls.

For example:
        "rtc"
                ihandle of package that supports the RTC device methods
        "mouse"
                ihandle of package that supports the MOUSE device methods.
etc....

For NVRAM, as defined, we also need to device a standard alias so that it
can be OPENed with alternative arguments.

        /ALIASES
           "nvram"
                standard alias for the node that implements the NVRAM methods.




[ P1275 Item #239 -- Received: Wed Mar  1 10:10:04 PST 1995 ]