Date: Sat, 16 Sep 1995 10:09:16 -0700
From: ron@apple.com (Ron Hochsprung)
Subject: Item #290: PCI Binding: requirements for PCI-PCI bridges


P1275 Openboot Working Group Proposal -- Proposal #:290 Ver 1

Title:          PCI-PCI bridge requirements

Author:         Ron Hochsprung

Date:           9/16/95

Ed/Tech:        Technical

Synopsis:       add requirements for PCI-PCI bridge bus nodes

Doc & Version:  PCI Binding 1.5

Problem:

        There is currently no information that directly reports the
        state of PCI-PCI bridge mapping registers.  This information
        is important for OSs that need to allocate address space for
        devices (i.e.,g hot-plug).

Proposal:

        Add a requirement for a bus node that represents a PCI-PCI bridge
        that it must have a "ranges" property, with entries that represent
        the mapping of Memory space, I/O space and Prefetchable Memory space
        to which it has been programmed.

QUESTION:  Do we want to say anything about how the ISA-mode and VGA-mode
        bits are programmed?  Do we want to suggest how they should be set?





[ P1275 Item #290 -- Received: Sat Sep 16 10:11:49 PDT 1995 ]