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      1 /*	$NetBSD: nvm.h,v 1.1 2014/02/24 07:23:43 skrll Exp $	*/
      2 
      3 /*	$OpenBSD: nvm.h,v 1.2 1998/11/23 03:28:22 mickey Exp $	*/
      4 
      5 /*
      6  * Copyright (c) 1990, 1994 The University of Utah and
      7  * the Computer Systems Laboratory at the University of Utah (CSL).
      8  * All rights reserved.
      9  *
     10  * Permission to use, copy, modify and distribute this software is hereby
     11  * granted provided that (1) source code retains these copyright, permission,
     12  * and disclaimer notices, and (2) redistributions including binaries
     13  * reproduce the notices in supporting documentation, and (3) all advertising
     14  * materials mentioning features or use of this software display the following
     15  * acknowledgement: ``This product includes software developed by the
     16  * Computer Systems Laboratory at the University of Utah.''
     17  *
     18  * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
     19  * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
     20  * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     21  *
     22  * CSL requests users of this software to return to csl-dist (at) cs.utah.edu any
     23  * improvements that they make and grant CSL redistribution rights.
     24  *
     25  * 	Utah $Hdr: nvm.h 1.4 94/12/14$
     26  *	Author: Jeff Forys, University of Utah CSL
     27  */
     28 
     29 #ifndef _MACHINE_NVM_H_
     30 #define	_MACHINE_NVM_H_
     31 
     32 /*
     33  * The PDC provides access to Non-Volatile Memory (NVM).  If this
     34  * is implemented (it's HVERSION dependent), the first 256 bytes
     35  * are formatted as follows:
     36  *
     37  *	0x000	+----------------------------+
     38  *		| Implementation information |
     39  *	0x024	+----------------------------+
     40  *		|                            |
     41  *		|      IPL information       |
     42  *		|                            |
     43  *	0x080	+----------------------------+
     44  *		|                            |
     45  *		|                            |
     46  *		|    OS Panic information    |
     47  *		|                            |
     48  *		|                            |
     49  *	0x100	+----------------------------+
     50  *
     51  * It appears that there are at least 256 bytes of NVM, and only
     52  * the "OS Panic information" is not architected.  This means that
     53  * we can use locations 0x80 - 0xFF for saving information across
     54  * boots (e.g. boot flags and boot device).  I think we should use
     55  * the higher portions of this space first, to avoid conflicting
     56  * with possible future HP-PA plans for the NVM.
     57  *
     58  * The PDC requires that NVM be read/written to in word multiples.
     59  */
     60 
     61 /*
     62  * Boot flags and boot device (0xF4 - 0xFF).
     63  */
     64 
     65 #define	NVM_BOOTDATA	0xF4		/* location of bootdata in NVM */
     66 #define	NVM_BOOTMAGIC	0xACCEDE	/* magic used for bootdata cksum */
     67 #define	NVM_BOOTCKSUM(bd) \
     68 	((unsigned int) NVM_BOOTMAGIC + (bd).flags + (bd).device)
     69 
     70 struct bootdata {
     71 	unsigned int cksum;		/* NVM_BOOTMAGIC + flags + device */
     72 	unsigned int flags;		/* boot flags */
     73 	unsigned int device;		/* boot device */
     74 };
     75 
     76 #endif	/* _MACHINE_NVM_H_ */
     77