Subject: Item #300: Device Ext: New property for supported number of SCSI targets
Cc: [email-masked], [email-masked], [email-masked], [email-masked], [email-masked], [email-masked]

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	From: [email-masked]

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 ]