420 lines
8.9 KiB
ArmAsm
420 lines
8.9 KiB
ArmAsm
/*
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* armboot - Startup Code for SA1100 CPU
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*
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* Copyright (C) 1998 Dan Malek <dmalek@jlc.net>
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* Copyright (C) 1999 Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se>
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* Copyright (C) 2000 Wolfgang Denk <wd@denx.de>
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* Copyright (c) 2001 Alex Züpke <azu@sysgo.de>
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <config.h>
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#include <version.h>
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/*
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*************************************************************************
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*
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* Jump vector table as in table 3.1 in [1]
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*
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*************************************************************************
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*/
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.globl _start
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_start: b reset
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ldr pc, _undefined_instruction
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ldr pc, _software_interrupt
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ldr pc, _prefetch_abort
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ldr pc, _data_abort
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ldr pc, _not_used
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ldr pc, _irq
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ldr pc, _fiq
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_undefined_instruction: .word undefined_instruction
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_software_interrupt: .word software_interrupt
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_prefetch_abort: .word prefetch_abort
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_data_abort: .word data_abort
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_not_used: .word not_used
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_irq: .word irq
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_fiq: .word fiq
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.balignl 16,0xdeadbeef
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/*
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*************************************************************************
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*
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* Startup Code (reset vector)
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*
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* do important init only if we don't start from memory!
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* relocate armboot to ram
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* setup stack
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* jump to second stage
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*
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*************************************************************************
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*/
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_TEXT_BASE:
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.word TEXT_BASE
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.globl _armboot_start
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_armboot_start:
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.word _start
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/*
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* These are defined in the board-specific linker script.
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*/
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.globl _bss_start
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_bss_start:
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.word __bss_start
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.globl _bss_end
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_bss_end:
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.word _end
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#ifdef CONFIG_USE_IRQ
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/* IRQ stack memory (calculated at run-time) */
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.globl IRQ_STACK_START
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IRQ_STACK_START:
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.word 0x0badc0de
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/* IRQ stack memory (calculated at run-time) */
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.globl FIQ_STACK_START
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FIQ_STACK_START:
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.word 0x0badc0de
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#endif
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/*
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* the actual reset code
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*/
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reset:
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/*
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* set the cpu to SVC32 mode
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*/
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mrs r0,cpsr
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bic r0,r0,#0x1f
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orr r0,r0,#0x13
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msr cpsr,r0
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/*
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* we do sys-critical inits only at reboot,
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* not when booting from ram!
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*/
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#ifndef CONFIG_SKIP_LOWLEVEL_INIT
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bl cpu_init_crit
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#endif
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#ifndef CONFIG_SKIP_RELOCATE_UBOOT
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relocate: /* relocate U-Boot to RAM */
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adr r0, _start /* r0 <- current position of code */
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ldr r1, _TEXT_BASE /* test if we run from flash or RAM */
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cmp r0, r1 /* don't reloc during debug */
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beq stack_setup
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ldr r2, _armboot_start
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ldr r3, _bss_start
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sub r2, r3, r2 /* r2 <- size of armboot */
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add r2, r0, r2 /* r2 <- source end address */
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copy_loop:
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ldmia r0!, {r3-r10} /* copy from source address [r0] */
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stmia r1!, {r3-r10} /* copy to target address [r1] */
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cmp r0, r2 /* until source end addreee [r2] */
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ble copy_loop
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#endif /* CONFIG_SKIP_RELOCATE_UBOOT */
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/* Set up the stack */
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stack_setup:
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ldr r0, _TEXT_BASE /* upper 128 KiB: relocated uboot */
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sub r0, r0, #CONFIG_SYS_MALLOC_LEN /* malloc area */
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sub r0, r0, #CONFIG_SYS_GBL_DATA_SIZE /* bdinfo */
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#ifdef CONFIG_USE_IRQ
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sub r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)
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#endif
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sub sp, r0, #12 /* leave 3 words for abort-stack */
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clear_bss:
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ldr r0, _bss_start /* find start of bss segment */
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ldr r1, _bss_end /* stop here */
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mov r2, #0x00000000 /* clear */
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clbss_l:str r2, [r0] /* clear loop... */
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add r0, r0, #4
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cmp r0, r1
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ble clbss_l
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ldr pc, _start_armboot
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_start_armboot: .word start_armboot
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/*
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*************************************************************************
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*
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* CPU_init_critical registers
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*
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* setup important registers
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* setup memory timing
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*
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*************************************************************************
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*/
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/* Interupt-Controller base address */
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IC_BASE: .word 0x90050000
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#define ICMR 0x04
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/* Reset-Controller */
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RST_BASE: .word 0x90030000
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#define RSRR 0x00
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#define RCSR 0x04
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/* PWR */
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PWR_BASE: .word 0x90020000
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#define PSPR 0x08
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#define PPCR 0x14
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cpuspeed: .word CONFIG_SYS_CPUSPEED
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cpu_init_crit:
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/*
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* mask all IRQs
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*/
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ldr r0, IC_BASE
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mov r1, #0x00
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str r1, [r0, #ICMR]
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/* set clock speed */
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ldr r0, PWR_BASE
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ldr r1, cpuspeed
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str r1, [r0, #PPCR]
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/*
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* before relocating, we have to setup RAM timing
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* because memory timing is board-dependend, you will
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* find a lowlevel_init.S in your board directory.
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*/
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mov ip, lr
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bl lowlevel_init
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mov lr, ip
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/*
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* disable MMU stuff and enable I-cache
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*/
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mrc p15,0,r0,c1,c0
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bic r0, r0, #0x00002000 @ clear bit 13 (X)
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bic r0, r0, #0x0000000f @ clear bits 3-0 (WCAM)
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orr r0, r0, #0x00001000 @ set bit 12 (I) Icache
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orr r0, r0, #0x00000002 @ set bit 2 (A) Align
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mcr p15,0,r0,c1,c0
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/*
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* flush v4 I/D caches
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*/
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mov r0, #0
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mcr p15, 0, r0, c7, c7, 0 /* flush v3/v4 cache */
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mcr p15, 0, r0, c8, c7, 0 /* flush v4 TLB */
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mov pc, lr
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/*
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*************************************************************************
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*
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* Interrupt handling
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*
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*************************************************************************
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*/
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@
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@ IRQ stack frame.
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@
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#define S_FRAME_SIZE 72
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#define S_OLD_R0 68
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#define S_PSR 64
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#define S_PC 60
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#define S_LR 56
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#define S_SP 52
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#define S_IP 48
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#define S_FP 44
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#define S_R10 40
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#define S_R9 36
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#define S_R8 32
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#define S_R7 28
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#define S_R6 24
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#define S_R5 20
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#define S_R4 16
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#define S_R3 12
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#define S_R2 8
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#define S_R1 4
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#define S_R0 0
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#define MODE_SVC 0x13
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#define I_BIT 0x80
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/*
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* use bad_save_user_regs for abort/prefetch/undef/swi ...
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* use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
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*/
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.macro bad_save_user_regs
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sub sp, sp, #S_FRAME_SIZE
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stmia sp, {r0 - r12} @ Calling r0-r12
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add r8, sp, #S_PC
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ldr r2, _armboot_start
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sub r2, r2, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
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sub r2, r2, #(CONFIG_SYS_GBL_DATA_SIZE+8) @ set base 2 words into abort stack
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ldmia r2, {r2 - r4} @ get pc, cpsr, old_r0
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add r0, sp, #S_FRAME_SIZE @ restore sp_SVC
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add r5, sp, #S_SP
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mov r1, lr
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stmia r5, {r0 - r4} @ save sp_SVC, lr_SVC, pc, cpsr, old_r
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mov r0, sp
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.endm
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.macro irq_save_user_regs
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sub sp, sp, #S_FRAME_SIZE
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stmia sp, {r0 - r12} @ Calling r0-r12
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add r8, sp, #S_PC
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stmdb r8, {sp, lr}^ @ Calling SP, LR
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str lr, [r8, #0] @ Save calling PC
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mrs r6, spsr
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str r6, [r8, #4] @ Save CPSR
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str r0, [r8, #8] @ Save OLD_R0
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mov r0, sp
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.endm
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.macro irq_restore_user_regs
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ldmia sp, {r0 - lr}^ @ Calling r0 - lr
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mov r0, r0
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ldr lr, [sp, #S_PC] @ Get PC
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add sp, sp, #S_FRAME_SIZE
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subs pc, lr, #4 @ return & move spsr_svc into cpsr
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.endm
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.macro get_bad_stack
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ldr r13, _armboot_start @ setup our mode stack
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sub r13, r13, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
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sub r13, r13, #(CONFIG_SYS_GBL_DATA_SIZE+8) @ reserved a couple spots in abort stack
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str lr, [r13] @ save caller lr / spsr
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mrs lr, spsr
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str lr, [r13, #4]
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mov r13, #MODE_SVC @ prepare SVC-Mode
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msr spsr_c, r13
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mov lr, pc
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movs pc, lr
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.endm
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.macro get_irq_stack @ setup IRQ stack
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ldr sp, IRQ_STACK_START
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.endm
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.macro get_fiq_stack @ setup FIQ stack
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ldr sp, FIQ_STACK_START
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.endm
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/*
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* exception handlers
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*/
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.align 5
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undefined_instruction:
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get_bad_stack
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bad_save_user_regs
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bl do_undefined_instruction
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.align 5
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software_interrupt:
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get_bad_stack
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bad_save_user_regs
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bl do_software_interrupt
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.align 5
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prefetch_abort:
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get_bad_stack
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bad_save_user_regs
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bl do_prefetch_abort
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.align 5
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data_abort:
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get_bad_stack
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bad_save_user_regs
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bl do_data_abort
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.align 5
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not_used:
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get_bad_stack
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bad_save_user_regs
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bl do_not_used
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#ifdef CONFIG_USE_IRQ
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.align 5
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irq:
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get_irq_stack
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irq_save_user_regs
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bl do_irq
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irq_restore_user_regs
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.align 5
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fiq:
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get_fiq_stack
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/* someone ought to write a more effiction fiq_save_user_regs */
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irq_save_user_regs
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bl do_fiq
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irq_restore_user_regs
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#else
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.align 5
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irq:
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get_bad_stack
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bad_save_user_regs
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bl do_irq
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.align 5
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fiq:
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get_bad_stack
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bad_save_user_regs
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bl do_fiq
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#endif
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.align 5
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.globl reset_cpu
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reset_cpu:
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ldr r0, RST_BASE
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mov r1, #0x0 @ set bit 3-0 ...
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str r1, [r0, #RCSR] @ ... to clear in RCSR
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mov r1, #0x1
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str r1, [r0, #RSRR] @ and perform reset
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b reset_cpu @ silly, but repeat endlessly
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