142 lines
3.3 KiB
ArmAsm
142 lines
3.3 KiB
ArmAsm
/*
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* U-boot - i386 Startup Code
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*
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* Copyright (c) 2002 Omicron Ceti AB, Daniel Engstr<EFBFBD>m <denaiel@omicron.se>
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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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.section .text
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.code32
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.globl _start
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.type _start, @function
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.globl _i386boot_start
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_i386boot_start:
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/*
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* This is the fail safe 32-bit bootstrap entry point. The
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* following code is not executed from a cold-reset (actually, a
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* lot of it is, but from real-mode after cold reset. It is
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* repeated here to put the board into a state as close to cold
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* reset as necessary)
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*/
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cli
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cld
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/* Turn of cache (this might require a 486-class CPU) */
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movl %cr0, %eax
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orl $0x60000000, %eax
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movl %eax, %cr0
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wbinvd
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/* Tell 32-bit code it is being entered from an in-RAM copy */
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movw $0x0000, %bx
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_start:
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/* This is the 32-bit cold-reset entry point */
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movl $0x18, %eax /* Load our segement registes, the
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* gdt have already been loaded by start16.S */
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movw %ax, %fs
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movw %ax, %ds
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movw %ax, %gs
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movw %ax, %es
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movw %ax, %ss
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/* Clear the interupt vectors */
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lidt blank_idt_ptr
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/*
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* Skip low-level board and memory initialization if not starting
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* from cold-reset. This allows us to do a fail safe boot-strap
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* into a new build of U-Boot from a known-good boot flash
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*/
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movw $0x0001, %ax
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cmpw %ax, %bx
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jne mem_init_ret
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/* We call a few functions in the board support package
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* since we have no stack yet we'll have to use %ebp
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* to store the return address */
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/* Early platform init (setup gpio, etc ) */
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jmp early_board_init
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.globl early_board_init_ret
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early_board_init_ret:
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/* size memory */
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jmp mem_init
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.globl mem_init_ret
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mem_init_ret:
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/* fetch memory size (into %eax) */
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jmp get_mem_size
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.globl get_mem_size_ret
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get_mem_size_ret:
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#if CONFIG_SYS_SDRAM_ECC_ENABLE
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/* Skip ECC initialization if not starting from cold-reset */
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movl %ebx, %ecx
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andl $GD_FLG_COLD_BOOT, %ecx
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jz init_ecc_ret
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jmp init_ecc
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.globl init_ecc_ret
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init_ecc_ret:
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#endif
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/* Check we have enough memory for stack */
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movl $CONFIG_SYS_STACK_SIZE, %ecx
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cmpl %ecx, %eax
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jb die
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mem_ok:
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/* Set stack pointer to upper memory limit*/
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movl %eax, %esp
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/* Test the stack */
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pushl $0
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popl %eax
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cmpl $0, %eax
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jne die
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push $0x55aa55aa
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popl %ecx
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cmpl $0x55aa55aa, %ecx
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jne die
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wbinvd
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/* Set the upper memory limit parameter */
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movl %esp, %eax
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subl $CONFIG_SYS_STACK_SIZE, %eax
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call board_init_f /* Enter, U-boot! */
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/* indicate (lack of) progress */
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movw $0x85, %ax
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die: hlt
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jmp die
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hlt
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blank_idt_ptr:
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.word 0 /* limit */
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.long 0 /* base */
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