u-boot/cpu/pxa/start.S

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/*
* armboot - Startup Code for XScale
*
* Copyright (C) 1998 Dan Malek <dmalek@jlc.net>
* Copyright (C) 1999 Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se>
* Copyright (C) 2000 Wolfgang Denk <wd@denx.de>
* Copyright (C) 2001 Alex Z<EFBFBD>pke <azu@sysgo.de>
* Copyright (C) 2002 Kyle Harris <kharris@nexus-tech.net>
* Copyright (C) 2003 Robert Schwebel <r.schwebel@pengutronix.de>
* Copyright (C) 2003 Kai-Uwe Bloehm <kai-uwe.bloem@auerswald.de>
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*
* See file CREDITS for list of people who contributed to this
* project.
*
* 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 program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <config.h>
#include <version.h>
.globl _start
_start: b reset
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ldr pc, _undefined_instruction
ldr pc, _software_interrupt
ldr pc, _prefetch_abort
ldr pc, _data_abort
ldr pc, _not_used
ldr pc, _irq
ldr pc, _fiq
_undefined_instruction: .word undefined_instruction
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_software_interrupt: .word software_interrupt
_prefetch_abort: .word prefetch_abort
_data_abort: .word data_abort
_not_used: .word not_used
_irq: .word irq
_fiq: .word fiq
.balignl 16,0xdeadbeef
/*
* Startup Code (reset vector)
*
* do important init only if we don't start from memory!
* - relocate armboot to ram
* - setup stack
* - jump to second stage
*/
_TEXT_BASE:
.word TEXT_BASE
.globl _armboot_start
_armboot_start:
.word _start
/*
* Note: _armboot_end_data and _armboot_end are defined
* by the (board-dependent) linker script.
* _armboot_end_data is the first usable FLASH address after armboot
*/
.globl _armboot_end_data
_armboot_end_data:
.word armboot_end_data
.globl _armboot_end
_armboot_end:
.word armboot_end
/*
* This is defined in the board specific linker script
*/
.globl _bss_start
_bss_start:
.word bss_start
.globl _bss_end
_bss_end:
.word bss_end
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/*
* _armboot_real_end is the first usable RAM address behind armboot
* and the various stacks
*/
.globl _armboot_real_end
_armboot_real_end:
.word 0x0badc0de
/*
* We relocate uboot to this address (end of RAM - 128 KiB)
*/
.globl _uboot_reloc
_uboot_reloc:
.word TEXT_BASE
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#ifdef CONFIG_USE_IRQ
/* IRQ stack memory (calculated at run-time) */
.globl IRQ_STACK_START
IRQ_STACK_START:
.word 0x0badc0de
/* IRQ stack memory (calculated at run-time) */
.globl FIQ_STACK_START
FIQ_STACK_START:
.word 0x0badc0de
#endif
/****************************************************************************/
/* */
/* the actual reset code */
/* */
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/****************************************************************************/
reset:
mrs r0,cpsr /* set the cpu to SVC32 mode */
bic r0,r0,#0x1f /* (superviser mode, M=10011) */
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orr r0,r0,#0x13
msr cpsr,r0
bl cpu_init_crit /* we do sys-critical inits */
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relocate: /* relocate U-Boot to RAM */
adr r0, _start /* r0 <- current position of code */
ldr r1, _TEXT_BASE /* test if we run from flash or RAM */
cmp r0, r1 /* don't reloc during debug */
beq stack_setup
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ldr r2, _armboot_start
ldr r3, _armboot_end
sub r2, r3, r2 /* r2 <- size of armboot */
add r2, r0, r2 /* r2 <- source end address */
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copy_loop:
ldmia r0!, {r3-r10} /* copy from source address [r0] */
stmia r1!, {r3-r10} /* copy to target address [r1] */
cmp r0, r2 /* until source end addreee [r2] */
ble copy_loop
/* Set up the stack */
stack_setup:
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ldr r0, _uboot_reloc /* upper 128 KiB: relocated uboot */
sub r0, r0, #CFG_MALLOC_LEN /* malloc area */
/* FIXME: bdinfo should be here */
sub sp, r0, #12 /* leave 3 words for abort-stack */
clear_bss:
ldr r0, _bss_start /* find start of bss segment */
add r0, r0, #4 /* start at first byte of bss */
ldr r1, _bss_end /* stop here */
mov r2, #0x00000000 /* clear */
clbss_l:str r2, [r0] /* clear loop... */
add r0, r0, #4
cmp r0, r1
bne clbss_l
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ldr pc, _start_armboot
_start_armboot: .word start_armboot
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/****************************************************************************/
/* */
/* CPU_init_critical registers */
/* */
/* - setup important registers */
/* - setup memory timing */
/* */
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/****************************************************************************/
/* Interrupt-Controller base address */
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IC_BASE: .word 0x40d00000
#define ICMR 0x04
/* Reset-Controller */
RST_BASE: .word 0x40f00030
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#define RCSR 0x00
/* Operating System Timer */
OSTIMER_BASE: .word 0x40a00000
#define OSMR3 0x0C
#define OSCR 0x10
#define OWER 0x18
#define OIER 0x1C
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/* Clock Manager Registers */
CC_BASE: .word 0x41300000
#define CCCR 0x00
cpuspeed: .word CFG_CPUSPEED
/* RS: ??? */
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.macro CPWAIT
mrc p15,0,r0,c2,c0,0
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mov r0,r0
sub pc,pc,#4
.endm
cpu_init_crit:
/* mask all IRQs */
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ldr r0, IC_BASE
mov r1, #0x00
str r1, [r0, #ICMR]
#if defined(CFG_CPUSPEED)
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/* set clock speed */
ldr r0, CC_BASE
ldr r1, cpuspeed
str r1, [r0, #CCCR]
mov r0, #2
mcr p14, 0, r0, c6, c0, 0
setspeed_done:
#endif
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/*
* before relocating, we have to setup RAM timing
* because memory timing is board-dependend, you will
* find a memsetup.S in your board directory.
*/
mov ip, lr
bl memsetup
mov lr, ip
/* Memory interfaces are working. Disable MMU and enable I-cache. */
ldr r0, =0x2001 /* enable access to all coproc. */
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mcr p15, 0, r0, c15, c1, 0
CPWAIT
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mcr p15, 0, r0, c7, c10, 4 /* drain the write & fill buffers */
CPWAIT
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mcr p15, 0, r0, c7, c7, 0 /* flush Icache, Dcache and BTB */
CPWAIT
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mcr p15, 0, r0, c8, c7, 0 /* flush instuction and data TLBs */
CPWAIT
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/* Enable the Icache */
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/*
mrc p15, 0, r0, c1, c0, 0
orr r0, r0, #0x1800
mcr p15, 0, r0, c1, c0, 0
CPWAIT
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*/
mov pc, lr
/****************************************************************************/
/* */
/* Interrupt handling */
/* */
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/****************************************************************************/
/* IRQ stack frame */
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#define S_FRAME_SIZE 72
#define S_OLD_R0 68
#define S_PSR 64
#define S_PC 60
#define S_LR 56
#define S_SP 52
#define S_IP 48
#define S_FP 44
#define S_R10 40
#define S_R9 36
#define S_R8 32
#define S_R7 28
#define S_R6 24
#define S_R5 20
#define S_R4 16
#define S_R3 12
#define S_R2 8
#define S_R1 4
#define S_R0 0
#define MODE_SVC 0x13
/* use bad_save_user_regs for abort/prefetch/undef/swi ... */
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.macro bad_save_user_regs
sub sp, sp, #S_FRAME_SIZE
stmia sp, {r0 - r12} /* Calling r0-r12 */
add r8, sp, #S_PC
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ldr r2, _armboot_end
add r2, r2, #CONFIG_STACKSIZE
sub r2, r2, #8
ldmia r2, {r2 - r4} /* get pc, cpsr, old_r0 */
add r0, sp, #S_FRAME_SIZE /* restore sp_SVC */
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add r5, sp, #S_SP
mov r1, lr
stmia r5, {r0 - r4} /* save sp_SVC, lr_SVC, pc, cpsr, old_r */
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mov r0, sp
.endm
/* use irq_save_user_regs / irq_restore_user_regs for */
/* IRQ/FIQ handling */
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.macro irq_save_user_regs
sub sp, sp, #S_FRAME_SIZE
stmia sp, {r0 - r12} /* Calling r0-r12 */
add r8, sp, #S_PC
stmdb r8, {sp, lr}^ /* Calling SP, LR */
str lr, [r8, #0] /* Save calling PC */
mrs r6, spsr
str r6, [r8, #4] /* Save CPSR */
str r0, [r8, #8] /* Save OLD_R0 */
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mov r0, sp
.endm
.macro irq_restore_user_regs
ldmia sp, {r0 - lr}^ @ Calling r0 - lr
mov r0, r0
ldr lr, [sp, #S_PC] @ Get PC
add sp, sp, #S_FRAME_SIZE
subs pc, lr, #4 @ return & move spsr_svc into cpsr
.endm
.macro get_bad_stack
ldr r13, _armboot_end @ setup our mode stack
add r13, r13, #CONFIG_STACKSIZE @ resides at top of normal stack
sub r13, r13, #8
str lr, [r13] @ save caller lr / spsr
mrs lr, spsr
str lr, [r13, #4]
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mov r13, #MODE_SVC @ prepare SVC-Mode
msr spsr_c, r13
mov lr, pc
movs pc, lr
.endm
.macro get_irq_stack @ setup IRQ stack
ldr sp, IRQ_STACK_START
.endm
.macro get_fiq_stack @ setup FIQ stack
ldr sp, FIQ_STACK_START
.endm
/****************************************************************************/
/* */
/* exception handlers */
/* */
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/****************************************************************************/
.align 5
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undefined_instruction:
get_bad_stack
bad_save_user_regs
bl do_undefined_instruction
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.align 5
software_interrupt:
get_bad_stack
bad_save_user_regs
bl do_software_interrupt
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.align 5
prefetch_abort:
get_bad_stack
bad_save_user_regs
bl do_prefetch_abort
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.align 5
data_abort:
get_bad_stack
bad_save_user_regs
bl do_data_abort
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.align 5
not_used:
get_bad_stack
bad_save_user_regs
bl do_not_used
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#ifdef CONFIG_USE_IRQ
.align 5
irq:
get_irq_stack
irq_save_user_regs
bl do_irq
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irq_restore_user_regs
.align 5
fiq:
get_fiq_stack
irq_save_user_regs /* someone ought to write a more */
bl do_fiq /* effiction fiq_save_user_regs */
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irq_restore_user_regs
#else
.align 5
irq:
get_bad_stack
bad_save_user_regs
bl do_irq
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.align 5
fiq:
get_bad_stack
bad_save_user_regs
bl do_fiq
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#endif
/****************************************************************************/
/* */
/* Reset function: the PXA250 doesn't have a reset function, so we have to */
/* perform a watchdog timeout for a soft reset. */
/* */
/****************************************************************************/
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.align 5
.globl reset_cpu
/* FIXME: this code is PXA250 specific. How is this handled on */
/* other XScale processors? */
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reset_cpu:
/* We set OWE:WME (watchdog enable) and wait until timeout happens */
ldr r0, OSTIMER_BASE
ldr r1, [r0, #OWER]
orr r1, r1, #0x0001 /* bit0: WME */
str r1, [r0, #OWER]
/* OS timer does only wrap every 1165 seconds, so we have to set */
/* the match register as well. */
ldr r1, [r0, #OSCR] /* read OS timer */
add r1, r1, #0x800 /* let OSMR3 match after */
add r1, r1, #0x800 /* 4096*(1/3.6864MHz)=1ms */
str r1, [r0, #OSMR3]
reset_endless:
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b reset_endless