diff options
Diffstat (limited to 'cpu/i386/start.S')
| -rw-r--r-- | cpu/i386/start.S | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/cpu/i386/start.S b/cpu/i386/start.S new file mode 100644 index 0000000..025555c --- /dev/null +++ b/cpu/i386/start.S @@ -0,0 +1,198 @@ +/* + * U-boot - i386 Startup Code + * + * Copyright (c) 2002 Omicron Ceti AB, Daniel Engström <denaiel@omicron.se> + * + * 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 + */ + + +#include <config.h> +#include <version.h> + + +.section .text +.code32 +.globl _start +.type _start, @function +.globl _i386boot_start +_i386boot_start: +_start: + movl $0x18,%eax /* Load our segement registes, the + * gdt have already been loaded by start16.S */ + movw %ax,%fs + movw %ax,%ds + movw %ax,%gs + movw %ax,%es + movw %ax,%ss + + /* We call a few functions in the board support package + * since we have no stack yet we'll have to use %ebp + * to store the return address */ + + /* Early platform init (setup gpio, etc ) */ + mov $early_board_init_ret, %ebp + jmp early_board_init +early_board_init_ret: + + /* The __port80 entry-point should be usabe by now */ + /* so we try to indicate progress */ + movw $0x01, %ax + movl $.progress0, %ebp + jmp __show_boot_progress +.progress0: + + /* size memory */ + mov $mem_init_ret, %ebp + jmp mem_init +mem_init_ret: + + /* check ammount of configured memory + * (we need atleast bss start+bss size+stack size) */ + movl $_i386boot_bss_start, %ecx /* BSS start */ + addl $_i386boot_bss_size, %ecx /* BSS size */ + addl $CFG_STACK_SIZE, %ecx + cmpl %ecx, %eax + jae mem_ok + + /* indicate (lack of) progress */ + movw $0x81, %ax + movl $.progress0a, %ebp + jmp __show_boot_progress +.progress0a: + jmp die +mem_ok: + + /* indicate progress */ + movw $0x02, %ax + movl $.progress1, %ebp + jmp __show_boot_progress +.progress1: + + /* create a stack after the bss */ + movl $_i386boot_bss_start, %eax + addl $_i386boot_bss_size, %eax + addl $CFG_STACK_SIZE, %eax + movl %eax, %esp + + pushl $0 + popl %eax + cmpl $0, %eax + jne no_stack + push $0x55aa55aa + popl %ebx + cmpl $0x55aa55aa, %ebx + je stack_ok + +no_stack: + /* indicate (lack of) progress */ + movw $0x82, %ax + movl $.progress1a, %ebp + jmp __show_boot_progress +.progress1a: + jmp die + + +stack_ok: + /* indicate progress */ + movw $0x03, %ax + movl $.progress2, %ebp + jmp __show_boot_progress +.progress2: + + /* copy data section to ram, size must be 4-byte aligned */ + movl $_i386boot_romdata_dest, %edi /* destination address */ + movl $_i386boot_romdata_start, %esi /* source address */ + movl $_i386boot_romdata_size, %ecx /* number of bytes to copy */ + movl %ecx, %eax + andl $3, %eax + jnz data_fail + + shrl $2, %ecx /* copy 4 byte each time */ + cld + cmpl $0, %ecx + je data_ok +data_segment: + movsl + loop data_segment + jmp data_ok +data_fail: + /* indicate (lack of) progress */ + movw $0x83, %ax + movl $.progress2a, %ebp + jmp __show_boot_progress +.progress2a: + jmp die + +data_ok: + + /* indicate progress */ + movw $0x04, %ax + movl $.progress3, %ebp + jmp __show_boot_progress +.progress3: + + /* clear bss section in ram, size must be 4-byte aligned */ + movl $_i386boot_bss_start, %eax /* BSS start */ + movl $_i386boot_bss_size, %ecx /* BSS size */ + movl %ecx, %eax + andl $3, %eax + jnz bss_fail + shrl $2, %ecx /* clear 4 byte each time */ + cld + cmpl $0, %ecx + je bss_ok +bss: + movl $0, (%edi) + add $4, %edi + loop bss + jmp bss_ok + +bss_fail: + /* indicate (lack of) progress */ + movw $0x84, %ax + movl $.progress3a, %ebp + jmp __show_boot_progress +.progress3a: + jmp die + +bss_ok: + + wbinvd + + + /* indicate progress */ + movw $0x05, %ax + movl $.progress4, %ebp + jmp __show_boot_progress +.progress4: + + call start_i386boot /* Enter, U-boot! */ + + /* indicate (lack of) progress */ + movw $0x85, %ax + movl $.progress4a, %ebp + jmp __show_boot_progress +.progress4a: + +die: hlt + jmp die + hlt + + |