71 lines
2.2 KiB
ArmAsm
71 lines
2.2 KiB
ArmAsm
/*
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* Early initialization code for ARM architecture.
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*
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* This file is based off of the OMAP3530/ARM Cortex start.S file from Das
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* U-Boot, which itself got the file from armboot.
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*
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* Copyright (c) 2004 Texas Instruments <r-woodruff2@ti.com>
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* Copyright (c) 2001 Marius Gröger <mag@sysgo.de>
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* Copyright (c) 2002 Alex Züpke <azu@sysgo.de>
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* Copyright (c) 2002 Gary Jennejohn <garyj@denx.de>
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* Copyright (c) 2003 Richard Woodruff <r-woodruff2@ti.com>
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* Copyright (c) 2003 Kshitij <kshitij@ti.com>
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* Copyright (c) 2006-2008 Syed Mohammed Khasim <x0khasim@ti.com>
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* Copyright (c) 2013 The Chromium OS Authors
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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; version 2 of
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* the License.
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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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#include <arch/asm.h>
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ENTRY(_start)
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/*
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* Set the cpu to System mode with IRQ and FIQ disabled. Prefetch/Data
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* aborts may happen early and crash before the abort handlers are
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* installed, but at least the problem will show up near the code that
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* causes it.
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*/
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msr cpsr_cxf, #0xdf
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/*
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* Initialize the stack to a known value. This is used to check for
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* stack overflow later in the boot process.
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*/
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ldr r0, =_stack
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ldr r1, =_estack
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ldr r2, =0xdeadbeef
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init_stack_loop:
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str r2, [r0]
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add r0, #4
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cmp r0, r1
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bne init_stack_loop
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/* Set stackpointer in internal RAM to call bootblock main() */
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call_bootblock:
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ldr sp, =_estack /* Set up stack pointer */
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ldr r0,=0x00000000
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/*
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* The current design of cpu_info places the
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* struct at the top of the stack. The number of
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* words pushed must be at least as large as that
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* struct.
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*/
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push {r0-r2}
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bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
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/*
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* Use "bl" instead of "b" even though we do not intend to return.
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* "bl" gets compiled to "blx" if we're transitioning from ARM to
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* Thumb. However, "b" will not and GCC may attempt to create a
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* wrapper which is currently broken.
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*/
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bl main
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ENDPROC(_start)
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