mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-06-09 23:36:03 +09:00
08deb6d36f
The full start-up sequence (TPL->SPL->U-Boot) can be a bit confusing since each phase has its own 'start' file. Add comments to explain this. Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
73 lines
1.8 KiB
ArmAsm
73 lines
1.8 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0+ */
|
|
/*
|
|
* 32-bit x86 Startup Code when running from SPL. This is the startup code in
|
|
* U-Boot proper, when SPL is used.
|
|
|
|
* Copyright 2018 Google, Inc
|
|
* Written by Simon Glass <sjg@chromium.org>
|
|
*/
|
|
|
|
#include <config.h>
|
|
|
|
.section .text.start
|
|
.code32
|
|
.globl _start
|
|
.type _start, @function
|
|
_start:
|
|
/* Set up memory using the existing stack */
|
|
movl $(CONFIG_SYS_CAR_ADDR + CONFIG_SYS_CAR_SIZE - 4), %eax
|
|
#ifdef CONFIG_DCACHE_RAM_MRC_VAR_SIZE
|
|
subl $CONFIG_DCACHE_RAM_MRC_VAR_SIZE, %eax
|
|
#endif
|
|
/*
|
|
* We don't subject CONFIG_DCACHE_RAM_MRC_VAR_SIZE since memory is
|
|
* already set up. This has the happy side-effect of putting gd in a
|
|
* new place separate from SPL, so the memset() in
|
|
* board_init_f_init_reserve() does not cause any problems (otherwise
|
|
* it would zero out the gd and crash)
|
|
*/
|
|
call board_init_f_alloc_reserve
|
|
mov %eax, %esp
|
|
|
|
call board_init_f_init_reserve
|
|
|
|
xorl %eax, %eax
|
|
call board_init_f
|
|
call board_init_f_r
|
|
|
|
/* Should not return here */
|
|
jmp .
|
|
|
|
.globl board_init_f_r_trampoline
|
|
.type board_init_f_r_trampoline, @function
|
|
board_init_f_r_trampoline:
|
|
/*
|
|
* SPL has been executed and SDRAM has been initialised, U-Boot code
|
|
* has been copied into RAM, BSS has been cleared and relocation
|
|
* adjustments have been made. It is now time to jump into the in-RAM
|
|
* copy of U-Boot
|
|
*
|
|
* %eax = Address of top of new stack
|
|
*/
|
|
|
|
/* Stack grows down from top of SDRAM */
|
|
movl %eax, %esp
|
|
|
|
/* Re-enter U-Boot by calling board_init_f_r() */
|
|
call board_init_f_r
|
|
|
|
die:
|
|
hlt
|
|
jmp die
|
|
hlt
|
|
|
|
.align 4
|
|
_dt_ucode_base_size:
|
|
/* These next two fields are filled in by binman */
|
|
.globl ucode_base
|
|
ucode_base: /* Declared in microcode.h */
|
|
.long 0 /* microcode base */
|
|
.globl ucode_size
|
|
ucode_size: /* Declared in microcode.h */
|
|
.long 0 /* microcode size */
|