431 lines
9.0 KiB
ArmAsm
431 lines
9.0 KiB
ArmAsm
/* vi: set ts=8 sw=8 noet: */
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/*
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* u-boot - Startup Code for XScale IXP
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*
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* Copyright (C) 2003 Kyle Harris <kharris@nexus-tech.net>
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*
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* Based on startup code example contained in the
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* Intel IXP4xx Programmer's Guide and past u-boot Start.S
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* samples.
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <asm-offsets.h>
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#include <config.h>
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#include <version.h>
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#include <asm/arch/ixp425.h>
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#define MMU_Control_M 0x001 /* Enable MMU */
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#define MMU_Control_A 0x002 /* Enable address alignment faults */
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#define MMU_Control_C 0x004 /* Enable cache */
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#define MMU_Control_W 0x008 /* Enable write-buffer */
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#define MMU_Control_P 0x010 /* Compatability: 32 bit code */
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#define MMU_Control_D 0x020 /* Compatability: 32 bit data */
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#define MMU_Control_L 0x040 /* Compatability: */
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#define MMU_Control_B 0x080 /* Enable Big-Endian */
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#define MMU_Control_S 0x100 /* Enable system protection */
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#define MMU_Control_R 0x200 /* Enable ROM protection */
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#define MMU_Control_I 0x1000 /* Enable Instruction cache */
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#define MMU_Control_X 0x2000 /* Set interrupt vectors at 0xFFFF0000 */
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#define MMU_Control_Init (MMU_Control_P|MMU_Control_D|MMU_Control_L)
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/*
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* Macro definitions
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*/
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/* Delay a bit */
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.macro DELAY_FOR cycles, reg0
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ldr \reg0, =\cycles
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subs \reg0, \reg0, #1
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subne pc, pc, #0xc
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.endm
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/* wait for coprocessor write complete */
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.macro CPWAIT reg
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mrc p15,0,\reg,c2,c0,0
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mov \reg,\reg
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sub pc,pc,#4
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.endm
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.globl _start
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_start:
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ldr pc, _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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_reset: .word reset
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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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* 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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.globl _TEXT_BASE
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_TEXT_BASE:
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#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_TEXT_BASE)
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.word CONFIG_SPL_TEXT_BASE
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#else
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.word CONFIG_SYS_TEXT_BASE
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#endif
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/*
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* These are defined in the board-specific linker script.
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* Subtracting _start from them lets the linker put their
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* relative position in the executable instead of leaving
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* them null.
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*/
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.globl _bss_start_ofs
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_bss_start_ofs:
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.word __bss_start - _start
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.globl _bss_end_ofs
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_bss_end_ofs:
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.word __bss_end - _start
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.globl _end_ofs
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_end_ofs:
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.word _end - _start
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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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/* IRQ stack memory (calculated at run-time) + 8 bytes */
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.globl IRQ_STACK_START_IN
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IRQ_STACK_START_IN:
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.word 0x0badc0de
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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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/* disable mmu, set big-endian */
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mov r0, #0xf8
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mcr p15, 0, r0, c1, c0, 0
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CPWAIT r0
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/* invalidate I & D caches & BTB */
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mcr p15, 0, r0, c7, c7, 0
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CPWAIT r0
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/* invalidate I & Data TLB */
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mcr p15, 0, r0, c8, c7, 0
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CPWAIT r0
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/* drain write and fill buffers */
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mcr p15, 0, r0, c7, c10, 4
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CPWAIT r0
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/* disable write buffer coalescing */
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mrc p15, 0, r0, c1, c0, 1
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orr r0, r0, #1
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mcr p15, 0, r0, c1, c0, 1
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CPWAIT r0
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/* set EXP CS0 to the optimum timing */
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ldr r1, =CONFIG_SYS_EXP_CS0
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ldr r2, =IXP425_EXP_CS0
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str r1, [r2]
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/* make sure flash is visible at 0 */
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mov r1, #CONFIG_SYS_SDR_CONFIG
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ldr r2, =IXP425_SDR_CONFIG
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str r1, [r2]
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/* disable refresh cycles */
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mov r1, #0
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ldr r3, =IXP425_SDR_REFRESH
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str r1, [r3]
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/* send nop command */
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mov r1, #3
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ldr r4, =IXP425_SDR_IR
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str r1, [r4]
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DELAY_FOR 0x4000, r0
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/* set SDRAM internal refresh val */
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ldr r1, =CONFIG_SYS_SDRAM_REFRESH_CNT
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str r1, [r3]
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DELAY_FOR 0x4000, r0
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/* send precharge-all command to close all open banks */
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mov r1, #2
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str r1, [r4]
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DELAY_FOR 0x4000, r0
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/* provide 8 auto-refresh cycles */
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mov r1, #4
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mov r5, #8
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111: str r1, [r4]
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DELAY_FOR 0x100, r0
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subs r5, r5, #1
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bne 111b
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/* set mode register in sdram */
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mov r1, #CONFIG_SYS_SDR_MODE_CONFIG
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str r1, [r4]
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DELAY_FOR 0x4000, r0
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/* send normal operation command */
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mov r1, #6
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str r1, [r4]
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DELAY_FOR 0x4000, r0
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/* invalidate I & D caches & BTB */
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mcr p15, 0, r0, c7, c7, 0
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CPWAIT r0
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/* invalidate I & Data TLB */
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mcr p15, 0, r0, c8, c7, 0
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CPWAIT r0
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/* drain write and fill buffers */
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mcr p15, 0, r0, c7, c10, 4
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CPWAIT r0
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/* remove flash mirror at 0x00000000 */
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ldr r2, =IXP425_EXP_CFG0
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ldr r1, [r2]
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bic r1, r1, #0x80000000
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str r1, [r2]
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/* invalidate I & Data TLB */
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mcr p15, 0, r0, c8, c7, 0
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CPWAIT r0
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/* enable I cache */
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mrc p15, 0, r0, c1, c0, 0
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orr r0, r0, #MMU_Control_I
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mcr p15, 0, r0, c1, c0, 0
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CPWAIT r0
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mrs r0,cpsr /* set the cpu to SVC32 mode */
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bic r0,r0,#0x1f /* (superviser mode, M=10011) */
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orr r0,r0,#0x13
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msr cpsr,r0
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bl _main
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/*------------------------------------------------------------------------------*/
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.globl c_runtime_cpu_setup
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c_runtime_cpu_setup:
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bx lr
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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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/* IRQ stack frame */
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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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/* use bad_save_user_regs for abort/prefetch/undef/swi ... */
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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, IRQ_STACK_START_IN
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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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/* use irq_save_user_regs / irq_restore_user_regs for */
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/* IRQ/FIQ handling */
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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, IRQ_STACK_START_IN @ setup our mode 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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/* */
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/* exception handlers */
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/* */
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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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irq_save_user_regs /* someone ought to write a more */
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bl do_fiq /* effiction fiq_save_user_regs */
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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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/****************************************************************************/
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/* */
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/* Reset function: Use Watchdog to reset */
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/* */
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/****************************************************************************/
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.align 5
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.globl reset_cpu
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reset_cpu:
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ldr r1, =0x482e
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ldr r2, =IXP425_OSWK
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str r1, [r2]
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ldr r1, =0x0fff
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ldr r2, =IXP425_OSWT
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str r1, [r2]
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ldr r1, =0x5
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ldr r2, =IXP425_OSWE
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str r1, [r2]
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b reset_endless
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reset_endless:
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b reset_endless
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