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rockbox/firmware/target/arm/tcc780x/crt0.S
Rob Purchase d6159ea7d7 Initial D2 sound playback support (known issues to follow on the CowonD2Info wiki page). 
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@17753 a1c6a512-1295-4272-9138-f99709370657
2008-06-22 18:48:22 +00:00

323 lines
8.7 KiB
ArmAsm
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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Linus Nielsen Feltzing
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
/* Arm bootloader and startup code based on startup.s from the iPodLinux loader
*
* Copyright (c) 2003, Daniel Palffy (dpalffy (at) rainstorm.org)
* Copyright (c) 2005, Bernard Leach <leachbj@bouncycastle.org>
*
*/
#include "config.h"
#include "cpu.h"
.section .init.text,"ax",%progbits
.global start
/* Telechips firmware files start with a 32-byte header, as part of the code. */
start:
#ifdef TCCBOOT
#ifdef BOOTLOADER
/* Add -DTCCBOOT to EXTRA_DEFINES in the bootloader Makefile to
enable building the bootloader to be appended to the end of the
original firmware, dual-booting based on a key-press.
The following two values are filled in by mktccboot.
*/
.word 0 /* Saved entrypoint of original firmware*/
.word 0 /* Location in RAM of the start of our bootloader */
#endif
#else
ldr pc, =start_loc /* jump to the main entry point */
.word 0xffff0601 /* Unknown magic */
.word 0x3a726556 /* "Ver:" */
.word 0x31373030 /* "0071" */
.word 0 /* First CRC32 */
.word 0 /* Unknown - always 0 */
.word 0 /* Second CRC32 */
.word 0 /* length of firmware file */
#ifdef COWON_D2
/* Some original firmwares have 0x40 bytes of zeroes here - we
don't know why, but err on the side of caution and include it
here. */
.space 0x40
#endif
#endif
start_loc:
#ifdef BOOTLOADER
#ifdef TCCBOOT
#ifdef COWON_D2
ldr r0, =0xf005a000
ldr r0, [r0, #0x20] /* Read GPIO A */
tst r0, #0x8
ldrne pc, [pc, #-28] /* Jump to original firmware if HOLD not pressed */
#else
#error No bootup key detection implemented for this target
#endif
/* Copy bootloader to safe area - 0x21F00000 (end of DRAM) */
/* TODO: Adjust this for other targets - DRAM + DRAMSIZE - 0x100000 */
ldr r0, [pc, #-28]
mov r1, #0x22000000
sub r1, r1, #0x100000
ldr r2, =_dataend
1:
cmp r2, r1
ldrhi r3, [r0], #4
strhi r3, [r1], #4
bhi 1b
ldr pc, =copied_start /* jump to the relocated start_loc: */
copied_start:
#endif
#else
/* We don't use interrupts in the bootloader */
/* Set up stack for IRQ mode */
mov r0,#0xd2
msr cpsr, r0
ldr sp, =irq_stack
/* Set up stack for FIQ mode */
mov r0,#0xd1
msr cpsr, r0
ldr sp, =fiq_stack
/* Load the banked FIQ mode registers with useful values here.
These values will be used in the FIQ handler in pcm-tcc780x.c */
.equ DADO_BASE, 0xF0059020
ldr r10, =DADO_BASE
ldr r11, =dma_play_data
/* Let abort and undefined modes use IRQ stack */
mov r0,#0xd7
msr cpsr, r0
ldr sp, =irq_stack
mov r0,#0xdb
msr cpsr, r0
ldr sp, =irq_stack
#endif
/* Switch to supervisor mode */
mov r0,#0xd3
msr cpsr, r0
ldr sp, =stackend
/* Enable MMU & caches. At present this is just doing what the OF does.
Ensure TCMs are enabled before copying the exception vectors to 0x0. */
mov r1, #0xf7000000 /* Virtual MMU Table base */
ldr r0, =0x1fe0c /* Region 0: 0x00000000-0xffffffff (4Gb) */
str r0, [r1] /* AP: 3 EN: 1 DO: 0 CACHE_ALL */
ldr r0, =0x2801ae24 /* Region 1: 0x28000000-0x2fffffff (128Mb) */
str r0, [r1,#4] /* AP: 3 EN: 1 DO: 1 BUFFERED */
ldr r0, =0x13e44 /* Region 2: 0x00000000-0x000fffff (1Mb) */
str r0, [r1,#8] /* AP: 3 EN: 1 DO: 2 BUFFERED */
ldr r0, =0x4001ce60 /* Region 3: 0x40000000-0x5fffffff (512Mb) */
str r0, [r1,#0xc] /* AP: 3 EN: 1 DO: 3 CACHE_NONE */
ldr r0, =0x6001be80 /* Region 4: 0x60000000-0x6fffffff (256Mb) */
str r0, [r1,#0x10] /* AP: 3 EN: 1 DO: 4 CACHE_NONE */
ldr r0, =0x3801aea4 /* Region 5: 0x38000000-0x3fffffff (128Mb) */
str r0, [r1,#0x14] /* AP: 3 EN: 1 DO: 5 BUFFERED */
ldr r0, =0x8001eec0 /* Region 6: 0x80000000-0xffffffff (2Gb) */
str r0, [r1,#0x18] /* AP: 3 EN: 1 DO: 6 CACHE_NONE */
ldr r0, =0x1001aee0 /* Region 7: 0x10000000-0x17ffffff (128Mb) */
str r0, [r1,#0x1c] /* AP: 3 EN: 1 DO: 7 CACHE_NONE */
add r1, r1, #0x8000
mcr p15, 0, r1, c2, c0, 0 /* Set TTBR = TABBASE (Virtual TLB) */
ldr r0, =0x55555555
mcr p15, 0, r0, c3, c0, 0 /* Domain access d0-d15 = 'client' */
ldr r0, =0xa0000011
mcr p15, 0, r0, c9, c1, 0 /* Data TCM: 0xA0000000-0xA00001fff (8Kb) */
mov r0, #0xd
mcr p15, 0, r0, c9, c1, 1 /* Instr. TCM: 0x00000000-0x00000fff (4Kb) */
mov r0, #0
mcr p15, 0, r0, c7, c5, 0 /* Invalidate Icache */
ldr r2, =0x5507d
mcr p15, 0, r2, c1, c0, 0 /* Enable MMU, I & D caches */
mcr p15, 0, r0, c7, c6, 0 /* Invalidate Dcache */
mcr p15, 0, r1, c8, c7, 0 /* Invalidate TLB */
#if !defined(BOOTLOADER) && !defined(STUB)
/* Copy exception handler code to address 0 */
ldr r2, =_vectorsstart
ldr r3, =_vectorsend
ldr r4, =_vectorscopy
1:
cmp r3, r2
ldrhi r5, [r4], #4
strhi r5, [r2], #4
bhi 1b
/* Copy the IRAM (SRAM) */
ldr r2, =_iramcopy
ldr r3, =_iramstart
ldr r4, =_iramend
1:
cmp r4, r3
ldrhi r5, [r2], #4
strhi r5, [r3], #4
bhi 1b
/* Zero out IBSS */
ldr r2, =_iedata
ldr r3, =_iend
mov r4, #0
1:
cmp r3, r2
strhi r4, [r2], #4
bhi 1b
/* Copy the ITCM */
ldr r2, =_itcmcopy
ldr r3, =_itcmstart
ldr r4, =_itcmend
1:
cmp r4, r3
ldrhi r5, [r2], #4
strhi r5, [r3], #4
bhi 1b
/* Copy the DTCM */
ldr r2, =_dtcmcopy
ldr r3, =_dtcmstart
ldr r4, =_dtcmend
1:
cmp r4, r3
ldrhi r5, [r2], #4
strhi r5, [r3], #4
bhi 1b
#endif /* !BOOTLOADER,!STUB */
/* 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 some stack and munge it with 0xdeadbeef */
ldr sp, =stackend
mov r3, sp
ldr r2, =stackbegin
ldr r4, =0xdeadbeef
1:
cmp r3, r2
strhi r4, [r2], #4
bhi 1b
bl main
/* main() should never return */
#ifndef BOOTLOADER
/* Exception handlers. Will be copied to address 0 after memory remapping */
.section .vectors,"aw"
ldr pc, [pc, #24]
ldr pc, [pc, #24]
ldr pc, [pc, #24]
ldr pc, [pc, #24]
ldr pc, [pc, #24]
ldr pc, [pc, #24]
ldr pc, [pc, #24]
ldr pc, [pc, #24]
/* Exception vectors */
.global vectors
vectors:
.word start
.word undef_instr_handler
.word software_int_handler
.word prefetch_abort_handler
.word data_abort_handler
.word reserved_handler
.word irq_handler
.word fiq_handler
.text
/* All illegal exceptions call into UIE with exception address as first
parameter. This is calculated differently depending on which exception
we're in. Second parameter is exception number, used for a string lookup
in UIE.
*/
undef_instr_handler:
mov r0, lr
mov r1, #0
b UIE
/* We run supervisor mode most of the time, and should never see a software
exception being thrown. Perhaps make it illegal and call UIE?
*/
software_int_handler:
reserved_handler:
movs pc, lr
prefetch_abort_handler:
sub r0, lr, #4
mov r1, #1
b UIE
data_abort_handler:
sub r0, lr, #8
mov r1, #2
b UIE
#if defined(STUB)
UIE:
b UIE
#endif
/* We don't use interrupts in the bootloader */
/* Align stacks to cache line boundary */
.balign 16
/* 256 words of IRQ stack */
.space 256*4
irq_stack:
/* 256 words of FIQ stack */
.space 256*4
fiq_stack:
#endif
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