2
* U-boot - x86 Startup Code
4
* (C) Copyright 2008-2011
5
* Graeme Russ, <graeme.russ@gmail.com>
8
* Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
10
* SPDX-License-Identifier: GPL-2.0+
15
#include <asm/global_data.h>
16
#include <asm/processor.h>
17
#include <asm/processor-flags.h>
18
#include <generated/generic-asm-offsets.h>
23
.type _start, @function
27
* This is the fail safe 32-bit bootstrap entry point. The
28
* following code is not executed from a cold-reset (actually, a
29
* lot of it is, but from real-mode after cold reset. It is
30
* repeated here to put the board into a state as close to cold
36
/* Turn off cache (this might require a 486-class CPU) */
38
orl $(X86_CR0_NW | X86_CR0_CD), %eax
42
/* Tell 32-bit code it is being entered from an in-RAM copy */
43
movw $GD_FLG_WARM_BOOT, %bx
47
* This is the 32-bit cold-reset entry point. Initialize %bx to 0
48
* in case we're preceeded by some sort of boot stub.
50
movw $GD_FLG_COLD_BOOT, %bx
53
/* Load the segement registes to match the gdt loaded in start16.S */
54
movl $(X86_GDT_ENTRY_32BIT_DS * X86_GDT_ENTRY_SIZE), %eax
61
/* Clear the interrupt vectors */
64
/* Early platform init (setup gpio, etc ) */
66
.globl early_board_init_ret
69
/* Initialise Cache-As-RAM */
74
* We now have CONFIG_SYS_CAR_SIZE bytes of Cache-As-RAM (or SRAM,
75
* or fully initialised SDRAM - we really don't care which)
76
* starting at CONFIG_SYS_CAR_ADDR to be used as a temporary stack
79
/* Stack grows down from top of CAR */
80
movl $(CONFIG_SYS_CAR_ADDR + CONFIG_SYS_CAR_SIZE), %esp
82
/* Reserve space on stack for global data */
83
subl $GENERATED_GBL_DATA_SIZE, %esp
85
/* Align global data to 16-byte boundary */
86
andl $0xfffffff0, %esp
88
/* Setup first parameter to setup_gdt */
91
/* Reserve space for global descriptor table */
92
subl $X86_GDT_SIZE, %esp
94
/* Align temporary global descriptor table to 16-byte boundary */
95
andl $0xfffffff0, %esp
97
/* Set second parameter to setup_gdt */
100
/* Setup global descriptor table so gd->xyz works */
103
/* Set parameter to board_init_f() to boot flags */
110
/* indicate (lack of) progress */
114
.globl board_init_f_r_trampoline
115
.type board_init_f_r_trampoline, @function
116
board_init_f_r_trampoline:
118
* SDRAM has been initialised, U-Boot code has been copied into
119
* RAM, BSS has been cleared and relocation adjustments have been
120
* made. It is now time to jump into the in-RAM copy of U-Boot
122
* %eax = Address of top of new stack
125
/* Stack grows down from top of SDRAM */
128
/* Reserve space on stack for global data */
129
subl $GENERATED_GBL_DATA_SIZE, %esp
131
/* Align global data to 16-byte boundary */
132
andl $0xfffffff0, %esp
134
/* Setup first parameter to memcpy (and setup_gdt) */
137
/* Setup second parameter to memcpy */
140
/* Set third parameter to memcpy */
141
movl $GENERATED_GBL_DATA_SIZE, %ecx
143
/* Copy global data from CAR to SDRAM stack */
146
/* Reserve space for global descriptor table */
147
subl $X86_GDT_SIZE, %esp
149
/* Align global descriptor table to 16-byte boundary */
150
andl $0xfffffff0, %esp
152
/* Set second parameter to setup_gdt */
155
/* Setup global descriptor table so gd->xyz works */
158
/* Re-enter U-Boot by calling board_init_f_r */
170
.p2align 2 /* force 4-byte alignment */
178
.long -0x1BADB002 - (1 << 16)
180
.long multiboot_header - _x86boot_start + CONFIG_SYS_TEXT_BASE
182
.long CONFIG_SYS_TEXT_BASE
188
.long CONFIG_SYS_TEXT_BASE