diff options
Diffstat (limited to 'board/eNET/eNET_start16.S')
| -rw-r--r-- | board/eNET/eNET_start16.S | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/board/eNET/eNET_start16.S b/board/eNET/eNET_start16.S new file mode 100644 index 0000000..48e4d83 --- /dev/null +++ b/board/eNET/eNET_start16.S @@ -0,0 +1,90 @@ +/* + * (C) Copyright 2008 + * Graeme Russ, graeme.russ@gmail.com. + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +/* + * 16bit initialization code. + * This code have to map the area of the boot flash + * that is used by U-boot to its final destination. + */ + +/* #include <asm/ic/sc520_defs.h> */ + +#include "hardware.h" + +.text +.section .start16, "ax" +.code16 +.globl board_init16 +board_init16: + /* Alias MMCR to 0xdf000 */ + movw $0xfffc, %dx + movl $0x800df0cb, %eax + outl %eax, %dx + + /* Set ds to point to MMCR alias */ + movw $0xdf00, %ax + movw %ax, %ds + + /* Map PAR for Boot Flash (BOOTCS, 512kB @ 0x380000000) */ + movl $0x00c0, %edi /* SC520_PAR14 */ + movl $0x8bfff800, %eax /* TODO: Check this */ + movl %eax, (%di) + + /* Map PAR for LED, Hex Switches (GPCS6, 20 Bytes @ 0x1000) */ + movl $0x00c4, %edi /* SC520_PAR15 */ + movl $0x38201000, %eax + movl %eax, (%di) + + /* Disable SDRAM write buffer */ + movw $0x0040, %di /* SC520_DBCTL */ + xorw %ax, %ax + movb %al, (%di) + + /* Disabe MMCR alias */ + movw $0xfffc, %dx + movl $0x000000cb, %eax + outl %eax, %dx + + /* the return address is stored in bp */ + jmp *%bp + +.section .bios, "ax" +.code16 +.globl realmode_reset +realmode_reset: + /* Alias MMCR to 0xdf000 */ + movw $0xfffc, %dx + movl $0x800df0cb, %eax + outl %eax, %dx + + /* Set ds to point to MMCR alias */ + movw $0xdf00, %ax + movw %ax, %ds + + /* issue software reset thorugh MMCR */ + movl $0xd72, %edi + movb $0x01, %al + movb %al, (%di) + +1: hlt + jmp 1 |