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rockbox/firmware/crt0.S
Thom Johansen 127c3febc1 UIE handler for ARM/iPod. Currently does not support interrupts. Will 
probably also work for other ARM based targets, like iFP.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@8388 a1c6a512-1295-4272-9138-f99709370657
2006-01-19 15:03:34 +00:00

833 lines
20 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.
*
****************************************************************************/
#include "config.h"
#include "cpu.h"
#if defined(CPU_ARM)
.section .init.text,"ax",%progbits
#else
.section .init.text,"ax",@progbits
#endif
.global start
start:
#if defined(CPU_ARM)
/* iPod 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>
*
*/
msr cpsr_c, #0xd3 /* enter supervisor mode, disable IRQ */
#ifndef BOOTLOADER
#if CONFIG_CPU == PP5002 || CONFIG_CPU == PP5020
b pad_skip
.space 50*4 /* (more than enough) space for exception vectors */
pad_skip:
/* We need to remap memory from wherever SDRAM is mapped natively, to
base address 0, so we can put our exception vectors there. We don't
want to do this remapping while executing from SDRAM, so we copy the
remapping code to IRAM, then execute from there. Hence, the following
code is compiled for address 0, but is currently executing at either
0x28000000 or 0x10000000, depending on chipset version. Do not use any
absolute addresses until remapping has been done. */
ldr r1, =0x40000000
ldr r2, =remap_start
ldr r3, =remap_end
and r5, pc, #0xff000000 /* adjust for execute address */
orr r2, r2, r5
orr r3, r3, r5
/* copy the code to 0x40000000 */
1:
ldr r4, [r2], #4
str r4, [r1], #4
cmp r2, r3
ble 1b
ldr r3, =0x3f84 /* r3 and r1 values here are magic, don't touch */
orr r3, r3, r5 /* adjust for execute address */
ldr r2, =0xf000f014
mov r1, #0x3a00
ldr r0, =0xf000f010
ldr r4, =0x40000000
mov pc, r4
remap_start:
str r1, [r0]
str r3, [r2]
ldr r0, L_post_remap
mov pc, r0
L_post_remap: .word remap_end
remap_end:
#endif /* PP specific */
/* Copy exception handler code to address 0 */
ldr r2, =ecode
ldr r3, =ecodeend
mov r4, #0
1:
cmp r3, r2
ldrhi r5, [r2], #4
strhi r5, [r4], #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 IRAM */
ldr r2, =_iramcopy
ldr r3, =_iramstart
ldr r4, =_iramend
1:
cmp r4, r3
ldrhi r5, [r2], #4
strhi r5, [r3], #4
bhi 1b
#endif /* !BOOTLOADER */
/* 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
#ifdef BOOTLOADER
#if CONFIG_CPU == PP5002 || CONFIG_CPU == PP5020
.equ PP5002_PROC_ID, 0xc4000000
.equ PP5002_COP_CTRL, 0xcf004058
.equ PP5020_PROC_ID, 0x60000000
.equ PP5020_COP_CTRL, 0x60007004
/* TODO: the high part of the address is probably dependent on CONFIG_CPU.
Since we tend to use ifdefs for each chipset target
anyway, we might as well just hardcode it here.
*/
/* get the high part of our execute address */
ldr r0, =0xff000000
and r8, pc, r0 @ r8 is used later
#if CONFIG_CPU==PP5002
mov r0, #PP5002_PROC_ID
#else
mov r0, #PP5020_PROC_ID
#endif
ldr r0, [r0]
and r0, r0, #0xff
cmp r0, #0x55
beq 1f
/* put us (co-processor) to sleep */
#if CONFIG_CPU==PP5002
ldr r4, =PP5002_COP_CTRL
mov r3, #0xca
#else
ldr r4, =PP5020_COP_CTRL
mov r3, #0x80000000
#endif
str r3, [r4]
ldr pc, =cop_wake_start
cop_wake_start:
/* jump the COP to startup */
ldr r0, =startup_loc
ldr pc, [r0]
1:
/* get the high part of our execute address */
ldr r2, =0xffffff00
and r4, pc, r2
/* Copy bootloader to safe area - 0x40000000 */
mov r5, #0x40000000
ldr r6, = _dataend
sub r0, r6, r5 /* length of loader */
add r0, r4, r0 /* r0 points to start of loader */
1:
cmp r5, r6
ldrcc r2, [r4], #4
strcc r2, [r5], #4
bcc 1b
ldr pc, =start_loc /* jump to the relocated start_loc: */
start_loc:
/* execute the loader - this will load an image to 0x10000000 */
bl main
/* The loader only returns if it is loading the Apple firmware or Linux -
the following code isn't executed when starting Rockbox */
/* save the startup address for the COP */
ldr r1, =startup_loc
str r0, [r1]
#if CONFIG_CPU==PP5002
/* make sure COP is sleeping */
ldr r4, =0xcf004050
1:
ldr r3, [r4]
ands r3, r3, #0x4000
beq 1b
/* wake up COP */
ldr r4, =PP5002_COP_CTRL
mov r3, #0xce
strh r3, [r4]
#else
/* make sure COP is sleeping */
ldr r4, =PP5020_COP_CTRL
1:
ldr r3, [r4]
ands r3, r3, #0x80000000
beq 1b
/* wake up COP */
@ldr r4, =PP5020_COP_CTRL
mov r3, #0x0
str r3, [r4]
#endif
/* jump to start location */
mov pc, r0
startup_loc:
.word 0x0
.align 8 /* starts at 0x100 */
.global boot_table
boot_table:
/* here comes the boot table, don't move its offset */
.space 400
#endif /* PP specific */
/* Code for ARM bootloader targets other than iPod go here */
#else /* BOOTLOADER */
/* Set up stack for IRQ mode */
msr cpsr_c, #0xd2
ldr sp, =irq_stack
/* Let abort mode use IRQ stack */
msr cpsr_c, #0xd7
ldr sp, =irq_stack
/* Switch to supervisor mode */
msr cpsr_c, #0xd3
ldr sp, =stackend
bl main
/* main() should never return */
/* Exception handlers. Will be copied to address 0 after memory remapping */
ecode:
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 */
.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
ecodeend:
.global irq
.global UIE
/* 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
fiq_handler:
subs pc, lr, #4
data_abort_handler:
sub r0, lr, #8
mov r1, #2
b UIE
irq_handler:
stmfd sp!, {r0-r3, r12, lr}
bl irq
ldmfd sp!, {r0-r3, r12, lr}
subs pc, lr, #4
/* 256 words of IRQ stack */
.space 256*4
irq_stack:
#endif /* BOOTLOADER */
#elif CONFIG_CPU == TCC730
/* Platform: Gmini 120/SP */
;; disable all interrupts
clrsr fe
clrsr ie
clrsr te
ld a14, #0x3F0000
ld r5, 0xA5
ldb @[a14 + 6], r5 ; disable watchdog
ld a11, #(_datacopy) ; where the data section is in the flash
ld a8, #(_datastart) ; destination
;; copy data section from flash to ram.
ld a9, #_datasize
ld r6, e9
cmp eq, r6, #0
brf .data_copy_loop
cmp eq, r9, #0
brt .data_copy_end
.data_copy_loop:
ldc r2, @a11
ldw @[a8 + 0], r2
add a11, #0x2
add a8, #0x2
sub r9, #0x2
sbc r6, #0
cmp ugt, r6, #0
brt .data_copy_loop
cmp ugt, r9, #0
brt .data_copy_loop
.data_copy_end:
;; zero out bss
ld r2, #0
ld a8, #(_bssstart) ; destination
ld a9, #_bsssize
ld r6, e9
cmp eq, r6, #0
brf .bss_init_loop
cmp eq, r9, #0
brt .bss_init_end
.bss_init_loop:
ldw @[a8 + 0], r2
add a8, #0x2
sub r9, #0x2
sbc r6, #0
cmp ugt, r6, #0
brt .bss_init_loop
cmp ugt, r9, #0
brt .bss_init_loop
.bss_init_end:
;; set stack pointer
ld a15, _stackend
;; go!
jsr _main
;; soft reset
ld a10, #0
ldc r10, @a10
jmp a10
.section .vectors, "ax"
irq_handler:
push r0, r1
push r2, r3
push r4, r5
push r6, r7
push a8, a9
push a10, a11
push a12, a13
push a14
ld a13, #0x3f0000
ldb r0, @[a13 + 0x26]
add r0, r0
ld a10, #_interrupt_vector
ldw a13, @[a10 + r0]
jsr a13
pop a14
pop a13, a12
pop a11, a10
pop a9, a8
pop r7, r6
pop r5, r4
pop r3, r2
pop r1, r0
ret_irq
#elif defined(IRIVER_H100_SERIES) || defined(IRIVER_H300_SERIES)
move.w #0x2700,%sr
move.l #vectors,%d0
movec.l %d0,%vbr
move.l #MBAR+1,%d0
movec.l %d0,%mbar
move.l #MBAR2+1,%d0
movec.l %d0,%mbar2
lea MBAR,%a0
lea MBAR2,%a1
/* 64K DMA-capable SRAM at 0x10000000
DMA is enabled and has priority in both banks
All types of accesses are allowed
(We might want to restrict that to save power) */
move.l #0x10000e01,%d0
movec.l %d0,%rambar1
/* 32K Non-DMA SRAM at 0x10010000
All types of accesses are allowed
(We might want to restrict that to save power) */
move.l #0x10010001,%d0
movec.l %d0,%rambar0
/* Chip select 0 - Flash ROM */
moveq.l #0x00,%d0 /* CSAR0 - Base = 0x00000000 */
move.l %d0,(0x080,%a0)
move.l #FLASH_SIZE-0x10000+1,%d0 /* CSMR0 - All access */
move.l %d0,(0x084,%a0)
move.l #0x00000180,%d0 /* CSCR0 - no wait states, 16 bits, no bursts */
move.l %d0,(0x088,%a0)
/* Chip select 1 - LCD controller */
move.l #0xf0000000,%d0 /* CSAR1 - Base = 0xf0000000 */
move.l %d0,(0x08c,%a0)
moveq.l #0x1,%d0 /* CSMR1 - 64K */
move.l %d0,(0x090,%a0)
move.l #0x00000180,%d0 /* CSCR1 - no wait states, 16 bits, no bursts */
move.l %d0,(0x094,%a0)
/* Chip select 2 - ATA controller */
move.l #0x20000000,%d0 /* CSAR2 - Base = 0x20000000 */
move.l %d0,(0x098,%a0)
move.l #0x000f0001,%d0 /* CSMR2 - 64K, Only data access */
move.l %d0,(0x09c,%a0)
move.l #0x00000080,%d0 /* CSCR2 - no wait states, 16 bits, no bursts */
move.l %d0,(0x0a0,%a0) /* NOTE: I'm not sure about the wait states.
We have to be careful with the access times,
since IORDY isn't connected to the HDD. */
#ifdef BOOTLOADER
/* The cookie is not reset. This must mean that the boot loader
has crashed. Let's start the original firmware immediately. */
lea 0x10017ffc,%a2
move.l (%a2),%d0
move.l #0xc0015a17,%d1
cmp.l %d0,%d1
bne.b .nocookie
/* Clear the cookie again */
clr.l (%a2)
jmp 8
.nocookie:
/* Set the cookie */
move.l %d1,(%a2)
/* Set up the DRAM controller. The refresh is based on the 11.2896MHz
clock (5.6448MHz bus frequency). We haven't yet started the PLL */
#if MEM < 32
move.w #0x8004,%d0 /* DCR - Synchronous, 80 cycle refresh */
#else
move.w #0x8001,%d0 /* DCR - Synchronous, 32 cycle refresh */
#endif
move.w %d0,(0x100,%a0)
/* Note on 32Mbyte models:
We place the SDRAM on an 0x1000000 (16M) offset because
the 5249 BGA chip has a fault which disables the use of A24. The
suggested workaround by FreeScale is to offset the base address by
half the DRAM size and increase the mask to the double.
In our case this means that we set the base address 16M ahead and
use a 64M mask.
*/
#if MEM < 32
move.l #0x31002324,%d0 /* DACR0 - Base 0x31000000, Banks on 21 and up,
CAS latency 1, Page mode, No refresh yet */
move.l %d0,(0x108,%a0)
move.l #0x00fc0001,%d0 /* Size: 16M */
move.l %d0,(0x10c,%a0) /* DMR0 - 32Mb */
#else
move.l #0x31002524,%d0 /* DACR0 - Base 0x31000000, Banks on 23 and up,
CAS latency 1, Page mode, No refresh yet */
move.l %d0,(0x108,%a0)
move.l #0x03fc0001,%d0 /* Size: 64M because of workaround above */
move.l %d0,(0x10c,%a0) /* DMR0 - 32Mb */
#endif
/* Precharge */
moveq.l #8,%d0
or.l %d0,(0x108,%a0) /* DACR0[IP] = 1, next access will issue a
Precharge command */
move.l #0xabcd1234,%d0
move.l %d0,0x31000000 /* Issue precharge command */
move.l #0x8000,%d0
or.l %d0,(0x108,%a0) /* Enable refresh */
/* Let it refresh */
move.l #500,%d0
.delayloop:
subq.l #1,%d0
bne.b .delayloop
/* Mode Register init */
moveq.l #0x40,%d0 /* DACR0[IMRS] = 1, next access will set the
Mode Register */
or.l %d0,(0x108,%a0)
move.l #0xabcd1234,%d0
move.l %d0,0x31000800 /* A12=1 means CASL=1 (a0 is not connected) */
/* DACR0[IMRS] gets deactivated by the SDRAM controller */
#endif /* BOOTLOADER */
/* Invalicate cache */
move.l #0x01000000,%d0
movec.l %d0,%cacr
/* Enable cache, default=non-cacheable,no buffered writes */
move.l #0x80000000,%d0
movec.l %d0,%cacr
/* Cache enabled in SDRAM only, buffered writes enabled */
move.l #0x3103c020,%d0
movec.l %d0,%acr0
moveq.l #0,%d0
movec.l %d0,%acr1
#ifndef BOOTLOADER
/* zero out .ibss */
lea _iedata,%a2
lea _iend,%a4
bra.b .iedatastart
.iedataloop:
clr.l (%a2)+
.iedatastart:
cmp.l %a2,%a4
bhi.b .iedataloop
/* copy the .iram section */
lea _iramcopy,%a2
lea _iramstart,%a3
lea _iramend,%a4
bra.b .iramstart
.iramloop:
move.l (%a2)+,(%a3)+
.iramstart:
cmp.l %a3,%a4
bhi.b .iramloop
#endif /* !BOOTLOADER */
#ifdef IRIVER_H300_SERIES
/* Set KEEP_ACT before doing the lengthy copy and zero-fill operations */
move.l #0x00080000,%d0
or.l %d0,(0xb4,%a1)
or.l %d0,(0xb8,%a1)
or.l %d0,(0xbc,%a1)
#endif
/* zero out bss */
lea _edata,%a2
lea _end,%a4
bra.b .edatastart
.edataloop:
clr.l (%a2)+
.edatastart:
cmp.l %a2,%a4
bhi.b .edataloop
/* copy the .data section */
lea _datacopy,%a2
lea _datastart,%a3
cmp.l %a2,%a3
beq.b .nodatacopy /* Don't copy if src and dest are equal */
lea _dataend,%a4
bra.b .datastart
.dataloop:
move.l (%a2)+,(%a3)+
.datastart:
cmp.l %a3,%a4
bhi.b .dataloop
.nodatacopy:
/* Munge the main stack */
lea stackbegin,%a2
lea stackend,%a4
move.l %a4,%sp
move.l #0xdeadbeef,%d0
.mungeloop:
move.l %d0,(%a2)+
cmp.l %a2,%a4
bhi.b .mungeloop
jsr main
.hoo:
bra.b .hoo
.section .resetvectors
vectors:
.long stackend
.long start
#elif defined(IRIVER_H300)
/* Platform: iRiver H320/H340 */
/* Fill in code here */
#else
/* Platform: Archos Jukebox */
mov.l .vbr_k,r1
#ifdef DEBUG
/* If we have built our code to be loaded via the standalone GDB
* stub, we will have out VBR at some other location than 0x9000000.
* We must copy the trap vectors for the GDB stub to our vector table. */
mov.l .orig_vbr_k,r2
/* Move the invalid instruction vector (4) */
mov #4,r0
shll2 r0
mov.l @(r0,r2),r3
mov.l r3,@(r0,r1)
/* Move the invalid slot vector (6) */
mov #6,r0
shll2 r0
mov.l @(r0,r2),r3
mov.l r3,@(r0,r1)
/* Move the bus error vector (9) */
mov #9,r0
shll2 r0
mov.l @(r0,r2),r3
mov.l r3,@(r0,r1)
/* Move the DMA bus error vector (10) */
mov #10,r0
shll2 r0
mov.l @(r0,r2),r3
mov.l r3,@(r0,r1)
/* Move the NMI vector as well (11) */
mov #11,r0
shll2 r0
mov.l @(r0,r2),r3
mov.l r3,@(r0,r1)
/* Move the UserBreak vector as well (12) */
mov #12,r0
shll2 r0
mov.l @(r0,r2),r3
mov.l r3,@(r0,r1)
/* Move the breakpoint trap vector (32) */
mov #32,r0
shll2 r0
mov.l @(r0,r2),r3
mov.l r3,@(r0,r1)
/* Move the IO trap vector (33) */
mov #33,r0
shll2 r0
mov.l @(r0,r2),r3
mov.l r3,@(r0,r1)
/* Move the serial Rx interrupt vector (105) */
mov #105,r0
shll2 r0
mov.l @(r0,r2),r3
mov.l r3,@(r0,r1)
/* Move the single step trap vector (127) */
mov #127,r0
shll2 r0
mov.l @(r0,r2),r3
mov.l r3,@(r0,r1)
#endif /* DEBUG */
ldc r1,vbr
mov #0,r0
ldc r0,gbr
/* zero out .ibss */
mov.l .iedata_k,r0
mov.l .iend_k,r1
bra .iedatastart
mov #0,r2
.iedataloop: /* backwards is faster and shorter */
mov.l r2,@-r1
.iedatastart:
cmp/hi r0,r1
bt .iedataloop
/* copy the .iram section */
mov.l .iramcopy_k,r0
mov.l .iram_k,r1
mov.l .iramend_k,r2
/* Note: We cannot put a PC relative load into the delay slot of a 'bra'
instruction (the offset would be wrong), but there is nothing else to
do before the loop, so the delay slot would be 'nop'. The cmp / bf
sequence is the same length, but more efficient. */
cmp/hi r1,r2
bf .noiramcopy
.iramloop:
mov.l @r0+,r3
mov.l r3,@r1
add #4,r1
cmp/hi r1,r2
bt .iramloop
.noiramcopy:
/* zero out bss */
mov.l .edata_k,r0
mov.l .end_k,r1
bra .edatastart
mov #0,r2
.edataloop: /* backwards is faster and shorter */
mov.l r2,@-r1
.edatastart:
cmp/hi r0,r1
bt .edataloop
/* copy the .data section, for rombased execution */
mov.l .datacopy_k,r0
mov.l .data_k,r1
cmp/eq r0,r1
bt .nodatacopy /* Don't copy if src and dest are equal */
mov.l .dataend_k,r2
cmp/hi r1,r2
bf .nodatacopy
.dataloop:
mov.l @r0+,r3
mov.l r3,@r1
add #4,r1
cmp/hi r1,r2
bt .dataloop
.nodatacopy:
/* Munge the main thread stack */
mov.l .stackbegin_k,r0
mov.l .stackend_k,r1
mov r1,r15
mov.l .deadbeef_k,r2
.mungeloop: /* backwards is faster and shorter */
mov.l r2,@-r1
cmp/hi r0,r1
bt .mungeloop
/* call the mainline */
mov.l .main_k,r0
jsr @r0
nop
.hoo:
bra .hoo
nop
.align 2
.vbr_k:
.long vectors
#ifdef DEBUG
.orig_vbr_k:
.long 0x09000000
#endif
.iedata_k:
.long _iedata
.iend_k:
.long _iend
.iramcopy_k:
.long _iramcopy
.iram_k:
.long _iramstart
.iramend_k:
.long _iramend
.edata_k:
.long _edata
.end_k:
.long _end
.datacopy_k:
.long _datacopy
.data_k:
.long _datastart
.dataend_k:
.long _dataend
.stackbegin_k:
.long _stackbegin
.stackend_k:
.long _stackend
.deadbeef_k:
.long 0xdeadbeef
.main_k:
.long _main
.section .resetvectors
vectors:
.long start
.long _stackend
.long start
.long _stackend
#endif
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