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rockbox/firmware/target/arm/crt0-pp502x-bl-usb.S

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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Linus Nielsen Feltzing
* Copyright (C) 2010 by Michael Sevakis
*
* 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"
/* PortalPlayer 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>
*
*/
.equ PROC_ID, 0x60000000
.equ CPU_IDIS, 0x60004028
.equ CPU_CTRL, 0x60007000
.equ CPU_STATUS, 0x60007000
.equ COP_IDIS, 0x60004038
.equ COP_CTRL, 0x60007004
.equ COP_STATUS, 0x60007004
.equ CPU_SLEEPING,0x80000000
.equ COP_SLEEPING,0x80000000
.equ SLEEP, 0x80000000
.equ WAKE, 0x00000000
.equ MMAP_LOG, 0xf000f000 /* MMAP0 */
.equ MMAP_PHYS, 0xf000f004
.equ INT_VECT_TBL,0x6000f100
.equ CACHE_CTRL, 0x6000c000
.equ CACHE_ENAB, 0x1
.equ CACHE_OP_COMMIT_DISCARD, 0x1
.equ CACHE_OP_COMMIT , 0x0
#if MEM > 32
.equ MMAP_MASK, 0x00003c00
#else
.equ MMAP_MASK, 0x00003e00
#endif
.equ MMAP_FLAGS, 0x00000f84
/*
* Entry point
*/
.section .init.text,"ax",%progbits
.global start
start:
b newstart
#ifdef IPOD_ARCH
.align 8 /* starts at 0x100 */
.global boot_table
boot_table:
/* here comes the boot table, don't move its offset - preceding
code+data must stay <= 256 bytes */
.space 400
#else /* !IPOD_ARCH */
/* (more than enough) space for exception vectors and mi4 magic */
.space 68*4
#endif /* IPOD_ARCH */
newstart:
msr cpsr_c, #0xd3 /* enter supervisor mode, disable IRQ/FIQ */
adr r4, start /* cache initial load address */
/* Copy startup stub to IRAM since we need to both move the bootloader's
* location, which could overlap itself, and setup the memory mapper. */
adr r0, start_stub_begin
mov r1, #0x40000000
adr r2, start_stub_end
1:
ldr r3, [r0], #4
str r3, [r1], #4
cmp r0, r2
blo 1b
mov pc, #0x40000000
start_stub_begin:
ldr r0, =PROC_ID
ldrb r0, [r0]
cmp r0, #0x55
beq cpu
cop:
mov r0, #CACHE_OP_COMMIT_DISCARD
bl cache_operation
ldr r1, =COP_CTRL
mov r0, #SLEEP
/* sleep us (co-processor) while bootloader is copied */
str r0, [r1]
nop
nop
nop
/* branch to final physical load address */
ldr r2, =1f
and r4, r4, #0xfc000000
add pc, r2, r4
1:
/* wait for bootloader to finish */
str r0, [r1]
nop
nop
nop
/* branch to the address returned by main() */
adr r0, startup_loc
ldr pc, [r0]
cpu:
/* wait for COP to sleep */
ldr r1, =COP_STATUS
1:
ldr r0, [r1]
tst r0, #COP_SLEEPING
beq 1b
mov r0, #CACHE_OP_COMMIT_DISCARD
bl cache_operation
/* move bootloader to the correct load address if needed */
ldr r1, =_loadaddress
cmp r4, r1
ldrne r2, =_loadaddressend
movne r0, r4
sublo r3, r2, r1 /* size */
addlo r0, r0, r3 /* initial load end addr */
1: /* lower to higher move - copy up */
cmphi r2, r1
ldrhi r3, [r0], #4
strhi r3, [r1], #4
bhi 1b
1: /* higher to lower move - copy down */
cmplo r1, r2
ldrlo r3, [r0, #-4]!
strlo r3, [r2, #-4]!
blo 1b
mov r0, #CACHE_OP_COMMIT
bl cache_operation
and r4, r4, #0xfc000000
ldr r0, =MMAP_FLAGS
orr r0, r0, r4 /* adjust for execute address */
ldr r1, =MMAP_MASK
ldr r2, =MMAP_LOG
ldr r3, =MMAP_PHYS
str r1, [r2] /* MMAP_LOG = MMAP_MASK */
str r0, [r3] /* MMAP_PHYS = MMAP_FLAGS | SDRAM base addr */
/* wake the COP to jump it to the correct place */
ldr r1, =COP_CTRL
mov r0, #WAKE
str r0, [r1]
/* wait for COP to halt then loading may proceed */
ldr r1, =COP_STATUS
1:
ldr r0, [r1]
tst r0, #COP_SLEEPING
beq 1b
ldr r0, =start_stub_end
add pc, r0, r4
cache_operation: /* (bool commit_discard) */
ldr r2, =CACHE_CTRL
ldr r1, [r2]
tst r1, #CACHE_ENAB
bxeq lr
cmp r0, #CACHE_OP_COMMIT
ldr r0, =0xf000f044
ldr r1, [r0]
orrne r1, r1, #0x6
orreq r1, r1, #0x2
str r1, [r0]
1:
ldr r1, [r2]
tst r1, #0x8000
bne 1b
bx lr
.ltorg /* constants used in stub come with us to IRAM */
start_stub_end:
/* now executing from final physical address */
/* copy the vector addresses to the table */
ldr r0, =INT_VECT_TBL
adr r1, vectorsstart
adr r2, vectorsend
1:
cmp r2, r1
ldrhi r3, [r1], #4
strhi r3, [r0], #4
bhi 1b
/* Copy the IRAM */
ldr r0, =_iramcopy
ldr r1, =_iramstart
ldr r2, =_iramend
1:
cmp r2, r1
ldrhi r3, [r0], #4
strhi r3, [r1], #4
bhi 1b
mov r0, #0
/* Zero out IBSS */
ldr r1, =_iedata
ldr r2, =_iend
1:
cmp r2, r1
strhi r0, [r1], #4
bhi 1b
/* Initialise bss/ncbss sections to zero */
ldr r1, =_edata
ldr r2, =_end
1:
cmp r2, r1
strhi r0, [r1], #4
bhi 1b
/* Set up some stack and munge it with 0xdeadbeef */
ldr r0, =0xdeadbeef
ldr r1, =stackbegin
ldr sp, =stackend
1:
cmp sp, r1
strhi r0, [r1], #4
bhi 1b
/* Set up stack for IRQ mode */
msr cpsr_c, #0xd2 /* IRQ/FIQ disabled */
ldr sp, =irq_stack
/* Let abort and undefined modes use IRQ stack */
msr cpsr_c, #0xd7 /* IRQ/FIQ disabled */
ldr sp, =irq_stack
msr cpsr_c, #0xdb /* IRQ/FIQ disabled */
ldr sp, =irq_stack
/* Switch back to supervisor mode */
msr cpsr_c, #0xd3
/* execute the loader - this will load an image to 0x10000000 */
ldr r0, =main
mov lr, pc
bx r0
/* store actual startup location returned by main() */
ldr r1, =startup_loc
str r0, [r1]
/* write back anything loaded + startup_loc */
mov r0, #CACHE_OP_COMMIT
bl cache_operation
mov r0, #0
/* disable memory mapper */
ldr r1, =MMAP_LOG
ldr r2, =MMAP_PHYS
str r0, [r1]
str r0, [r2]
/* bring COP back to life */
ldr r1, =COP_CTRL
mov r0, #WAKE
str r0, [r1]
/* after this point, r0-r3 are reserved for OF magic */
#if defined(SANSA_C200) || defined(PHILIPS_HDD1630)
/* Magic for loading the c200 OF */
ldr r0, =0xb00d10ad
mov r1, #0x700
ldr r2, =0xfff0
mov r3, #0x7
#endif
#if defined(PHILIPS_HDD6330)
/* Magic for loading the HDD6XX0 OF */
ldr r0, =0xb00d10ad
mov r1, #0x800
ldr r2, =0xfff0
mov r3, #0x7
#endif
/* branch to the address returned by main() */
adr r4, startup_loc
ldr pc, [r4]
startup_loc:
.word 0x00000000
/* exception handlers: will be copied to local vector table */
vectorsstart:
.word newstart
.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
vectorsend:
.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:
sub r0, lr, #4
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
/* should never happen in the bootloader */
fiq_handler:
subs pc, lr, #4
/* 256 words of IRQ stack */
.section .bss
.balign 16
.space 256*4
irq_stack:
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