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rockbox/firmware/target/arm/tcc780x/crt0.S
Rob Purchase f4deea6027 D2: Update dual boot to use the hold switch. Update bootloader to show messages until HOLD released, keep holding POWER to show old debug screen (these modes will eventually be removed). 
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@17032 a1c6a512-1295-4272-9138-f99709370657
2008-04-08 08:01:18 +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
/* 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.
NB: On the D2 TCCBOOT currently only works in USB boot mode (via tcctool)
When flashed to the device, the OF will boot as normal - but holding a
key to boot Rockbox results in a blank screen and crashed player.
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 */
#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 - 0x21000000 (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
/* 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
#if !defined(STUB)
.global irq
.global fiq
.global UIE
#endif
/* 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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