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Graeme Russc620c012008-12-07 10:28:57 +11001/*
2 * (C) Copyright 2008
3 * Graeme Russ, graeme.russ@gmail.com.
4 *
5 * See file CREDITS for list of people who contributed to this
6 * project.
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 as
10 * published by the Free Software Foundation; either version 2 of
11 * the License, or (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21 * MA 02111-1307 USA
22 */
23
24/*
25 * 16bit initialization code.
26 * This code have to map the area of the boot flash
27 * that is used by U-boot to its final destination.
28 */
29
30/* #include <asm/ic/sc520_defs.h> */
31
32#include "hardware.h"
33
34.text
35.section .start16, "ax"
36.code16
37.globl board_init16
38board_init16:
39 /* Alias MMCR to 0xdf000 */
40 movw $0xfffc, %dx
41 movl $0x800df0cb, %eax
42 outl %eax, %dx
43
44 /* Set ds to point to MMCR alias */
45 movw $0xdf00, %ax
46 movw %ax, %ds
47
48 /* Map PAR for Boot Flash (BOOTCS, 512kB @ 0x380000000) */
49 movl $0x00c0, %edi /* SC520_PAR14 */
50 movl $0x8bfff800, %eax /* TODO: Check this */
51 movl %eax, (%di)
52
53 /* Map PAR for LED, Hex Switches (GPCS6, 20 Bytes @ 0x1000) */
54 movl $0x00c4, %edi /* SC520_PAR15 */
55 movl $0x38201000, %eax
56 movl %eax, (%di)
57
58 /* Disable SDRAM write buffer */
59 movw $0x0040, %di /* SC520_DBCTL */
60 xorw %ax, %ax
61 movb %al, (%di)
62
63 /* Disabe MMCR alias */
64 movw $0xfffc, %dx
65 movl $0x000000cb, %eax
66 outl %eax, %dx
67
68 /* the return address is stored in bp */
69 jmp *%bp
70
71.section .bios, "ax"
72.code16
73.globl realmode_reset
Graeme Russ0fc1b492009-11-24 20:04:19 +110074.hidden realmode_reset
75.type realmode_reset, @function
Graeme Russc620c012008-12-07 10:28:57 +110076realmode_reset:
77 /* Alias MMCR to 0xdf000 */
78 movw $0xfffc, %dx
79 movl $0x800df0cb, %eax
80 outl %eax, %dx
81
82 /* Set ds to point to MMCR alias */
83 movw $0xdf00, %ax
84 movw %ax, %ds
85
86 /* issue software reset thorugh MMCR */
87 movl $0xd72, %edi
88 movb $0x01, %al
89 movb %al, (%di)
90
911: hlt
92 jmp 1