From CBellman@corp.adaptec.com  Thu Nov 16 12:30:31 1995
Date: 16 Nov 95 12:31:00 EST
Subject: Item #300: Device Ext: max-scsi-targets property

P1275 Open Firmware Working Group Proposal -- Proposal #:300 Ver 1

Title:			New property for supported number of SCSI targets

Author:			Chris Bellman

Date:			Nov 16, 1995

Ed/Tech:		Technical

Synopsis:		prop-name, indicating the number of SCSI targets 
			supported by a controller

Doc & Version:	Device Support Extensions to IEEE Std 1275-1994, 
		Core Errata & Device Extensions

Problem:

In consideration of IEEE 1394, SSA, Fibre Channel, and future SCSI bus 
architectures, there exists the need for software to communicate the
maximum number of SCSI targets supported by a bus controller.  Regardless
of the width of the parallel SCSI bus, there is an architectural concept
of a maximum of 64 bits for the unique identifier, and since the 
number of devices supported is a function of the physical and transport 
layers, SCSI has no restrictions on this.  SCSI-2 supports up to 8 targets
on an 8-bit narrow bus, and up to 16 targets on a 16-bit or 32-bit wide bus;
The SCSI-3 physical layer supports up to 32 targets on a 32-bit wide parallel
bus, and many more on the three differential serial versions.

Proposal:

Add the following standard property definition to the Device Support 
Extensions to IEEE Std 1275-1994 document:

9.1.  Properties for SCSI Bus Nodes

"max-scsi-targets"

	prop-name, indicating the maximum number of SCSI targets supported by 
	this controller.

	prop-encoded-array:  one integer, encoded as with encode-int.

	This property specifies the 32-bit maximum number of SCSI device target 
	identifiers supported by the SCSI bus controller represented by this
	node.  The absense of this property indicates an assumed maximum of
	eight (8) targets.  


Ammend the Core Errata, Appendix E.6.3, as follows:

E.6.3  hacom.fth

...

: show-children  ( -- )
   open  0=  if  ." Can't open SCSI host adapter" cr  exit  then
   " max-scsi-targets"  get-my-property  if  8  else  decode-int nip nip  
then
   0 ?do
      i probe-target  if
         ." Target " i . cr
         8 0  ?do  i j show-lun  loop
      then
   loop
;

...

[ P1275 Item #300 -- Received: Thu Nov 16 12:30:34 PST 1995 ]