1/*	$NetBSD: nvm.h,v 1.2 2009/05/08 09:33:58 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@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
70struct 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