84 lines
1.8 KiB
ArmAsm
84 lines
1.8 KiB
ArmAsm
/*
|
|
* Startup code for use with the u-boot bootloader.
|
|
*
|
|
* Copyright (C) 2004-2006 Atmel Corporation
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
#include <asm/setup.h>
|
|
#include <asm/thread_info.h>
|
|
#include <asm/sysreg.h>
|
|
|
|
/*
|
|
* The kernel is loaded where we want it to be and all caches
|
|
* have just been flushed. We get two parameters from u-boot:
|
|
*
|
|
* r12 contains a magic number (ATAG_MAGIC)
|
|
* r11 points to a tag table providing information about
|
|
* the system.
|
|
*/
|
|
.section .init.text,"ax"
|
|
.global _start
|
|
_start:
|
|
/* Initialize .bss */
|
|
lddpc r2, bss_start_addr
|
|
lddpc r3, end_addr
|
|
mov r0, 0
|
|
mov r1, 0
|
|
1: st.d r2++, r0
|
|
cp r2, r3
|
|
brlo 1b
|
|
|
|
/* Initialize status register */
|
|
lddpc r0, init_sr
|
|
mtsr SYSREG_SR, r0
|
|
|
|
/* Set initial stack pointer */
|
|
lddpc sp, stack_addr
|
|
sub sp, -THREAD_SIZE
|
|
|
|
#ifdef CONFIG_FRAME_POINTER
|
|
/* Mark last stack frame */
|
|
mov lr, 0
|
|
mov r7, 0
|
|
#endif
|
|
|
|
/* Check if the boot loader actually provided a tag table */
|
|
lddpc r0, magic_number
|
|
cp.w r12, r0
|
|
brne no_tag_table
|
|
|
|
/*
|
|
* Save the tag table address for later use. This must be done
|
|
* _after_ .bss has been initialized...
|
|
*/
|
|
lddpc r0, tag_table_addr
|
|
st.w r0[0], r11
|
|
|
|
/* Jump to loader-independent setup code */
|
|
rjmp kernel_entry
|
|
|
|
.align 2
|
|
magic_number:
|
|
.long ATAG_MAGIC
|
|
tag_table_addr:
|
|
.long bootloader_tags
|
|
bss_start_addr:
|
|
.long __bss_start
|
|
end_addr:
|
|
.long _end
|
|
init_sr:
|
|
.long 0x007f0000 /* Supervisor mode, everything masked */
|
|
stack_addr:
|
|
.long init_thread_union
|
|
panic_addr:
|
|
.long panic
|
|
|
|
no_tag_table:
|
|
sub r12, pc, (. - 2f)
|
|
/* branch to panic() which can be far away with that construct */
|
|
lddpc pc, panic_addr
|
|
2: .asciz "Boot loader didn't provide correct magic number\n"
|