mirror of
https://github.com/brain-hackers/u-boot-brain
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aefaff8ed8
The call to FspInitEntry is done in arch/x86/lib/fsp/fsp_car.S so far. It worked pretty well but looks not that good. Apart from doing too much work than just enabling CAR, it cannot read the configuration data from device tree at that time. Now we want to move it a little bit later as part of init_sequence_f[] being called by board_init_f(). This way it looks and works better in the U-Boot initialization path. Due to FSP's design, after calling FspInitEntry it will not return to its caller, instead it jumps to a continuation function which is given by bootloader with a new stack in system memory. The original stack in the CAR is gone, but its content is perserved by FSP and described by a bootloader temporary memory HOB. Technically we can recover anything we had before in the previous stack, but that is way too complicated. To make life much easier, in the FSP continuation routine we just simply call fsp_init_done() and jump back to car_init_ret() to redo the whole board_init_f() initialization, but this time with a non-zero HOB list pointer saved in U-Boot's global data so that we can bypass the FspInitEntry for the second time. Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Acked-by: Simon Glass <sjg@chromium.org> Tested-by: Andrew Bradford <andrew.bradford@kodakalaris.com> Tested-by: Simon Glass <sjg@chromium.org>
250 lines
5.6 KiB
ArmAsm
250 lines
5.6 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 <asm/global_data.h>
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#include <asm/post.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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#include <generated/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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/* Save BIST */
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movl %eax, %ebp
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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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post_code(POST_START)
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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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#ifndef CONFIG_HAVE_FSP
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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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* and early malloc area. The MRC requires some space at the top.
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*
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* Stack grows down from top of CAR. We have:
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*
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* top-> CONFIG_SYS_CAR_ADDR + CONFIG_SYS_CAR_SIZE
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* MRC area
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* global_data
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* x86 global descriptor table
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* early malloc area
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* stack
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* bottom-> CONFIG_SYS_CAR_ADDR
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*/
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movl $(CONFIG_SYS_CAR_ADDR + CONFIG_SYS_CAR_SIZE - 4), %esp
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#ifdef CONFIG_DCACHE_RAM_MRC_VAR_SIZE
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subl $CONFIG_DCACHE_RAM_MRC_VAR_SIZE, %esp
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#endif
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#else
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/*
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* When we get here after car_init, esp points to a temporary stack
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* and esi holds the HOB list address returned by the FSP.
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*/
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#endif
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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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post_code(POST_START_STACK)
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/* Zero the global data since it won't happen later */
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xorl %eax, %eax
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movl $GENERATED_GBL_DATA_SIZE, %ecx
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movl %esp, %edi
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rep stosb
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#ifdef CONFIG_HAVE_FSP
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test %esi, %esi
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jz skip_hob
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/* Store HOB list */
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movl %esp, %edx
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addl $GD_HOB_LIST, %edx
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movl %esi, (%edx)
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skip_hob:
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#endif
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/* Setup first parameter to setup_gdt, pointer to global_data */
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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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movl %esp, %ecx
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#if defined(CONFIG_SYS_MALLOC_F_LEN)
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subl $CONFIG_SYS_MALLOC_F_LEN, %esp
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movl %eax, %edx
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addl $GD_MALLOC_BASE, %edx
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movl %esp, (%edx)
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#endif
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/* Store BIST */
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movl %eax, %edx
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addl $GD_BIST, %edx
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movl %ebp, (%edx)
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/* Set second parameter to setup_gdt */
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movl %ecx, %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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post_code(POST_START_DONE)
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xorl %eax, %eax
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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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/* Set if we need to disable CAR */
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.weak car_uninit
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movl $car_uninit, %eax
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cmpl $0, %eax
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jz 1f
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call car_uninit
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1:
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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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