rockbox/firmware/target/arm/imx233/crt0.S
Amaury Pouly f33330c0ff arm: factor all exception handlers out of the crt0.S files
Remove the implementations of all exceptions handlers from the
various crt0.S files and have a single implementation in system-arm.h
The new implementation is weak so that it can be overwritten by some
specific code (like the unwinder)

Change-Id: Ib3e041ed6037376bbe0e79286057e1051640dd90
Reviewed-on: http://gerrit.rockbox.org/205
Reviewed-by: Marcin Bukat <marcin.bukat@gmail.com>
2012-04-06 13:46:32 +02:00

171 lines
4.6 KiB
ArmAsm

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2011 by Amaury Pouly
*
* 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
#include "cpu.h"
.section .vectors,"ax",%progbits
.code 32
/* most handlers are in DRAM which is too far away for a relative jump */
ldr pc, =start
ldr pc, =undef_instr_handler
ldr pc, =software_int_handler
ldr pc, =prefetch_abort_handler
ldr pc, =data_abort_handler
ldr pc, =reserved_handler
ldr pc, =irq_handler
ldr pc, =fiq_handler
/* When starting, we will be running at 0x40000000 most probably
* but the code is expected to be loaded at 0x4xxxxxxx (uncached) and to be
* running at virtual address 0xyyyyyyyy (cached). So we first
* need to move everything to the right locationn then we setup the mmu and
* jump to the final virtual address. */
.text
.global start
/** The code below must be able to run at any address **/
start:
/* Copy running address */
sub r7, pc, #8
/* Save r0 */
mov r6, r0
/* enter supervisor mode, disable IRQ/FIQ */
msr cpsr_c, #0xd3
/* Disable MMU, disable caching and buffering;
* use low exception range address (the core uses high range by default) */
mrc p15, 0, r0, c1, c0, 0
ldr r1, =0x3005
bic r0, r1
mcr p15, 0, r0, c1, c0, 0
/* To call the C code we need a stack, since the stack is in virtual memory
* use the stack's physical address */
ldr sp, =stackend_phys
/* Enable MMU */
bl memory_init
/* Copy the DRAM
* Assume the dram binary blob is located at the loading address (r5) */
mov r2, r7
ldr r3, =_dramcopystart
ldr r4, =_dramcopyend
1:
cmp r4, r3
ldrhi r5, [r2], #4
strhi r5, [r3], #4
bhi 1b
mov r2, #0
mcr p15, 0, r2, c7, c5, 0 @ Invalidate ICache
/* Jump to real location */
ldr pc, =remap
remap:
/** The code below is be running at the right virtual address **/
/* Zero out IBSS */
ldr r2, =_iedata
ldr r3, =_iend
mov r4, #0
1:
cmp r3, r2
strhi r4, [r2], #4
bhi 1b
/* Copy the IRAM */
/* must be done before bss is zeroed */
ldr r2, =_iramcopy
ldr r3, =_iramstart
ldr r4, =_iramend
1:
cmp r4, r3
ldrhi r5, [r2], #4
strhi r5, [r3], #4
bhi 1b
#ifdef HAVE_INIT_ATTR
/* copy init data to codec buffer */
/* must be done before bss is zeroed */
ldr r2, =_initcopy
ldr r3, =_initstart
ldr r4, =_initend
1:
cmp r4, r3
ldrhi r5, [r2], #4
strhi r5, [r3], #4
bhi 1b
mov r2, #0
mcr p15, 0, r2, c7, c5, 0 @ Invalidate ICache
#endif
/* Initialise bss section to zero */
ldr r2, =_edata
ldr r3, =_end
mov r4, #0
1:
cmp r3, r2
strhi r4, [r2], #4
bhi 1b
/* Set up stack for IRQ mode */
msr cpsr_c, #0xd2
ldr sp, =irq_stack
/* Set up stack for FIQ mode */
msr cpsr_c, #0xd1
ldr sp, =fiq_stack
/* Let svc, abort and undefined modes use irq stack */
msr cpsr_c, #0xd3
ldr sp, =irq_stack
msr cpsr_c, #0xd7
ldr sp, =irq_stack
msr cpsr_c, #0xdb
ldr sp, =irq_stack
/* Switch to sys mode */
msr cpsr_c, #0xdf
/* Set up some stack and munge it with 0xdeadbeef */
ldr sp, =stackend
ldr r2, =stackbegin
ldr r3, =0xdeadbeef
1:
cmp sp, r2
strhi r3, [r2], #4
bhi 1b
/* Jump to main */
mov r0, r6
mov r1, r7
bl main
1:
b 1b
/* 256 words of IRQ stack */
.space 256*4
irq_stack:
/* 256 words of FIQ stack */
.space 256*4
fiq_stack:
end: