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/*
* linux/arch/arm26/kernel/head.S
*
* Copyright (C) 1994-2000 Russell King
* Copyright (C) 2003 Ian Molton
*
* 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.
*
* 26-bit kernel startup code
*/
#include <linux/config.h>
#include <linux/linkage.h>
#include <asm/mach-types.h>
.globl swapper_pg_dir
.equ swapper_pg_dir, 0x0207d000
/*
* Entry point.
*/
.section ".init.text",#alloc,#execinstr
ENTRY(stext)
__entry:
cmp pc, #0x02000000
ldrlt pc, LC0 @ if 0x01800000, call at 0x02080000
teq r0, #0 @ Check for old calling method
blne oldparams @ Move page if old
adr r0, LC0
ldmib r0, {r2-r5, sp} @ Setup stack (and fetch other values)
mov r0, #0 @ Clear BSS
1: cmp r2, r3
strcc r0, [r2], #4
bcc 1b
bl detect_proc_type
str r0, [r4]
bl detect_arch_type
str r0, [r5]
#ifdef CONFIG_XIP_KERNEL
ldr r3, ETEXT @ data section copy
ldr r4, SDATA
ldr r5, EDATA
1:
ldr r6, [r3], #4
str r6, [r4], #4
cmp r4, r5
blt 1b
#endif
mov fp, #0
b start_kernel
LC0: .word _stext
.word __bss_start @ r2
.word _end @ r3
.word processor_id @ r4
.word __machine_arch_type @ r5
.word init_thread_union+8192 @ sp
#ifdef CONFIG_XIP_KERNEL
ETEXT: .word _endtext
SDATA: .word _sdata
EDATA: .word __bss_start
#endif
arm2_id: .long 0x41560200 @ ARM2 and 250 dont have a CPUID
arm250_id: .long 0x41560250 @ So we create some after probing for them
.align
oldparams: mov r4, #0x02000000
add r3, r4, #0x00080000
add r4, r4, #0x0007c000
1: ldmia r0!, {r5 - r12}
stmia r4!, {r5 - r12}
cmp r4, r3
blt 1b
mov pc, lr
/*
* We need some way to automatically detect the difference between
* these two machines. Unfortunately, it is not possible to detect
* the presence of the SuperIO chip, because that will hang the old
* Archimedes machines solid.
*/
/* DAG: Outdated, these have been combined !!!!!!! */
detect_arch_type:
#if defined(CONFIG_ARCH_ARC)
mov r0, #MACH_TYPE_ARCHIMEDES
#elif defined(CONFIG_ARCH_A5K)
mov r0, #MACH_TYPE_A5K
#endif
mov pc, lr
detect_proc_type:
mov ip, lr
mov r2, #0xea000000 @ Point undef instr to continuation
adr r0, continue - 12
orr r0, r2, r0, lsr #2
mov r1, #0
str r0, [r1, #4]
ldr r0, arm2_id
swp r2, r2, [r1] @ check for swp (ARM2 cant)
ldr r0, arm250_id
mrc 15, 0, r3, c0, c0 @ check for CP#15 (ARM250 cant)
mov r0, r3
continue: mov r2, #0xeb000000 @ Make undef vector loop
sub r2, r2, #2
str r2, [r1, #4]
mov pc, ip
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