189 lines
4.3 KiB
ArmAsm
189 lines
4.3 KiB
ArmAsm
/*
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* U-boot - x86 Startup Code
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*
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* (C) Copyright 2008-2011
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* Graeme Russ, <graeme.russ@gmail.com>
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*
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* (C) Copyright 2002
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* Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <config.h>
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#include <version.h>
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#include <asm/global_data.h>
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#include <asm/processor.h>
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#include <asm/processor-flags.h>
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#include <generated/generic-asm-offsets.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 _x86boot_start
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_x86boot_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 off cache (this might require a 486-class CPU) */
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movl %cr0, %eax
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orl $(X86_CR0_NW | X86_CR0_CD), %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 $GD_FLG_WARM_BOOT, %bx
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jmp 1f
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_start:
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/*
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* This is the 32-bit cold-reset entry point. Initialize %bx to 0
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* in case we're preceeded by some sort of boot stub.
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*/
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movw $GD_FLG_COLD_BOOT, %bx
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1:
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/* Load the segement registes to match the gdt loaded in start16.S */
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movl $(X86_GDT_ENTRY_32BIT_DS * X86_GDT_ENTRY_SIZE), %eax
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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 interrupt vectors */
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lidt blank_idt_ptr
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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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/* Initialise Cache-As-RAM */
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jmp car_init
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.globl car_init_ret
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car_init_ret:
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/*
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* We now have CONFIG_SYS_CAR_SIZE bytes of Cache-As-RAM (or SRAM,
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* or fully initialised SDRAM - we really don't care which)
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* starting at CONFIG_SYS_CAR_ADDR to be used as a temporary stack
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*/
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/* Stack grows down from top of CAR */
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movl $(CONFIG_SYS_CAR_ADDR + CONFIG_SYS_CAR_SIZE), %esp
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/* Reserve space on stack for global data */
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subl $GENERATED_GBL_DATA_SIZE, %esp
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/* Align global data to 16-byte boundary */
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andl $0xfffffff0, %esp
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/* Setup first parameter to setup_gdt */
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movl %esp, %eax
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/* Reserve space for global descriptor table */
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subl $X86_GDT_SIZE, %esp
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/* Align temporary global descriptor table to 16-byte boundary */
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andl $0xfffffff0, %esp
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/* Set second parameter to setup_gdt */
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movl %esp, %edx
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/* Setup global descriptor table so gd->xyz works */
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call setup_gdt
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/* Set parameter to board_init_f() to boot flags */
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xorl %eax, %eax
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movw %bx, %ax
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/* Enter, U-boot! */
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call board_init_f
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/* indicate (lack of) progress */
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movw $0x85, %ax
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jmp die
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.globl board_init_f_r_trampoline
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.type board_init_f_r_trampoline, @function
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board_init_f_r_trampoline:
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/*
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* SDRAM has been initialised, U-Boot code has been copied into
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* RAM, BSS has been cleared and relocation adjustments have been
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* made. It is now time to jump into the in-RAM copy of U-Boot
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*
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* %eax = Address of top of new stack
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*/
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/* Stack grows down from top of SDRAM */
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movl %eax, %esp
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/* Reserve space on stack for global data */
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subl $GENERATED_GBL_DATA_SIZE, %esp
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/* Align global data to 16-byte boundary */
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andl $0xfffffff0, %esp
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/* Setup first parameter to memcpy (and setup_gdt) */
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movl %esp, %eax
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/* Setup second parameter to memcpy */
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fs movl 0, %edx
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/* Set third parameter to memcpy */
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movl $GENERATED_GBL_DATA_SIZE, %ecx
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/* Copy global data from CAR to SDRAM stack */
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call memcpy
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/* Reserve space for global descriptor table */
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subl $X86_GDT_SIZE, %esp
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/* Align global descriptor table to 16-byte boundary */
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andl $0xfffffff0, %esp
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/* Set second parameter to setup_gdt */
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movl %esp, %edx
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/* Setup global descriptor table so gd->xyz works */
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call setup_gdt
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/* Re-enter U-Boot by calling board_init_f_r */
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call board_init_f_r
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die:
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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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.p2align 2 /* force 4-byte alignment */
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multiboot_header:
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/* magic */
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.long 0x1BADB002
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/* flags */
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.long (1 << 16)
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/* checksum */
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.long -0x1BADB002 - (1 << 16)
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/* header addr */
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.long multiboot_header - _x86boot_start + CONFIG_SYS_TEXT_BASE
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/* load addr */
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.long CONFIG_SYS_TEXT_BASE
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/* load end addr */
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.long 0
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/* bss end addr */
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.long 0
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/* entry addr */
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.long CONFIG_SYS_TEXT_BASE
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