1/*
2 *	Copyright (c) 2001, 2003  Maciej W. Rozycki
3 *
4 *	DEC MS02-NV (54-20948-01) battery backed-up NVRAM module for
5 *	DECstation/DECsystem 5000/2x0 and DECsystem 5900 and 5900/260
6 *	systems.
7 *
8 *	This program is free software; you can redistribute it and/or
9 *	modify it under the terms of the GNU General Public License
10 *	as published by the Free Software Foundation; either version
11 *	2 of the License, or (at your option) any later version.
12 *
13 *	$Id: ms02-nv.h,v 1.1.1.1 2007/08/03 18:52:43 Exp $
14 */
15
16#include <linux/ioport.h>
17#include <linux/mtd/mtd.h>
18
19/*
20 * Addresses are decoded as follows:
21 *
22 * 0x000000 - 0x3fffff	SRAM
23 * 0x400000 - 0x7fffff	CSR
24 *
25 * Within the SRAM area the following ranges are forced by the system
26 * firmware:
27 *
28 * 0x000000 - 0x0003ff	diagnostic area, destroyed upon a reboot
29 * 0x000400 - ENDofRAM	storage area, available to operating systems
30 *
31 * but we can't really use the available area right from 0x000400 as
32 * the first word is used by the firmware as a status flag passed
33 * from an operating system.  If anything but the valid data magic
34 * ID value is found, the firmware considers the SRAM clean, i.e.
35 * containing no valid data, and disables the battery resulting in
36 * data being erased as soon as power is switched off.  So the choice
37 * for the start address of the user-available is 0x001000 which is
38 * nicely page aligned.  The area between 0x000404 and 0x000fff may
39 * be used by the driver for own needs.
40 *
41 * The diagnostic area defines two status words to be read by an
42 * operating system, a magic ID to distinguish a MS02-NV board from
43 * anything else and a status information providing results of tests
44 * as well as the size of SRAM available, which can be 1MiB or 2MiB
45 * (that's what the firmware handles; no idea if 2MiB modules ever
46 * existed).
47 *
48 * The firmware only handles the MS02-NV board if installed in the
49 * last (15th) slot, so for any other location the status information
50 * stored in the SRAM cannot be relied upon.  But from the hardware
51 * point of view there is no problem using up to 14 such boards in a
52 * system -- only the 1st slot needs to be filled with a DRAM module.
53 * The MS02-NV board is ECC-protected, like other MS02 memory boards.
54 *
55 * The state of the battery as provided by the CSR is reflected on
56 * the two onboard LEDs.  When facing the battery side of the board,
57 * with the LEDs at the top left and the battery at the bottom right
58 * (i.e. looking from the back side of the system box), their meaning
59 * is as follows (the system has to be powered on):
60 *
61 * left LED		battery disable status: lit = enabled
62 * right LED		battery condition status: lit = OK
63 */
64
65/* MS02-NV iomem register offsets. */
66#define MS02NV_CSR		0x400000	/* control & status register */
67
68/* MS02-NV CSR status bits. */
69#define MS02NV_CSR_BATT_OK	0x01		/* battery OK */
70#define MS02NV_CSR_BATT_OFF	0x02		/* battery disabled */
71
72
73/* MS02-NV memory offsets. */
74#define MS02NV_DIAG		0x0003f8	/* diagnostic status */
75#define MS02NV_MAGIC		0x0003fc	/* MS02-NV magic ID */
76#define MS02NV_VALID		0x000400	/* valid data magic ID */
77#define MS02NV_RAM		0x001000	/* user-exposed RAM start */
78
79/* MS02-NV diagnostic status bits. */
80#define MS02NV_DIAG_TEST	0x01		/* SRAM test done (?) */
81#define MS02NV_DIAG_RO		0x02		/* SRAM r/o test done */
82#define MS02NV_DIAG_RW		0x04		/* SRAM r/w test done */
83#define MS02NV_DIAG_FAIL	0x08		/* SRAM test failed */
84#define MS02NV_DIAG_SIZE_MASK	0xf0		/* SRAM size mask */
85#define MS02NV_DIAG_SIZE_SHIFT	0x10		/* SRAM size shift (left) */
86
87/* MS02-NV general constants. */
88#define MS02NV_ID		0x03021966	/* MS02-NV magic ID value */
89#define MS02NV_VALID_ID		0xbd100248	/* valid data magic ID value */
90#define MS02NV_SLOT_SIZE	0x800000	/* size of the address space
91						   decoded by the module */
92
93
94typedef volatile u32 ms02nv_uint;
95
96struct ms02nv_private {
97	struct mtd_info *next;
98	struct {
99		struct resource *module;
100		struct resource *diag_ram;
101		struct resource *user_ram;
102		struct resource *csr;
103	} resource;
104	u_char *addr;
105	size_t size;
106	u_char *uaddr;
107};
108