1/* 2 * U-boot - x86 Startup Code 3 * 4 * (C) Copyright 2008-2011 5 * Graeme Russ, <graeme.russ@gmail.com> 6 * 7 * (C) Copyright 2002 8 * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se> 9 * 10 * See file CREDITS for list of people who contributed to this 11 * project. 12 * 13 * This program is free software; you can redistribute it and/or 14 * modify it under the terms of the GNU General Public License as 15 * published by the Free Software Foundation; either version 2 of 16 * the License, or (at your option) any later version. 17 * 18 * This program is distributed in the hope that it will be useful, 19 * but WITHOUT ANY WARRANTY; without even the implied warranty of 20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 21 * GNU General Public License for more details. 22 * 23 * You should have received a copy of the GNU General Public License 24 * along with this program; if not, write to the Free Software 25 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 26 * MA 02111-1307 USA 27 */ 28 29#include <config.h> 30#include <version.h> 31#include <asm/global_data.h> 32#include <asm/processor-flags.h> 33#include <generated/asm-offsets.h> 34 35.section .text 36.code32 37.globl _start 38.type _start, @function 39.globl _x86boot_start 40_x86boot_start: 41 /* 42 * This is the fail safe 32-bit bootstrap entry point. The 43 * following code is not executed from a cold-reset (actually, a 44 * lot of it is, but from real-mode after cold reset. It is 45 * repeated here to put the board into a state as close to cold 46 * reset as necessary) 47 */ 48 cli 49 cld 50 51 /* Turn off cache (this might require a 486-class CPU) */ 52 movl %cr0, %eax 53 orl $(X86_CR0_NW | X86_CR0_CD), %eax 54 movl %eax, %cr0 55 wbinvd 56 57_start: 58 /* This is the 32-bit cold-reset entry point */ 59 60 /* Load the segement registes to match the gdt loaded in start16.S */ 61 movl $0x18, %eax 62 movw %ax, %fs 63 movw %ax, %ds 64 movw %ax, %gs 65 movw %ax, %es 66 movw %ax, %ss 67 68 /* Clear the interrupt vectors */ 69 lidt blank_idt_ptr 70 71 /* Early platform init (setup gpio, etc ) */ 72 jmp early_board_init 73.globl early_board_init_ret 74early_board_init_ret: 75 76 /* Initialise Cache-As-RAM */ 77 jmp car_init 78.globl car_init_ret 79car_init_ret: 80 /* 81 * We now have CONFIG_SYS_CAR_SIZE bytes of Cache-As-RAM (or SRAM, 82 * or fully initialised SDRAM - we really don't care which) 83 * starting at CONFIG_SYS_CAR_ADDR to be used as a temporary stack 84 */ 85 movl $CONFIG_SYS_INIT_SP_ADDR, %esp 86 87 /* Set parameter to board_init_f() to boot flags */ 88 xorl %eax, %eax 89 movw %bx, %ax 90 91 /* Enter, U-boot! */ 92 call board_init_f 93 94 /* indicate (lack of) progress */ 95 movw $0x85, %ax 96 jmp die 97 98.globl relocate_code 99.type relocate_code, @function 100relocate_code: 101 /* 102 * SDRAM has been initialised, U-Boot code has been copied into 103 * RAM, BSS has been cleared and relocation adjustments have been 104 * made. It is now time to jump into the in-RAM copy of U-Boot 105 * 106 * %eax = Address of top of stack 107 * %edx = Address of Global Data 108 * %ecx = Base address of in-RAM copy of U-Boot 109 */ 110 111 /* Setup stack in RAM */ 112 movl %eax, %esp 113 114 /* Setup call address of in-RAM copy of board_init_r() */ 115 movl $board_init_r, %ebp 116 addl (GENERATED_GD_RELOC_OFF)(%edx), %ebp 117 118 /* Setup parameters to board_init_r() */ 119 movl %edx, %eax 120 movl %ecx, %edx 121 122 /* Jump to in-RAM copy of board_init_r() */ 123 call *%ebp 124 125die: 126 hlt 127 jmp die 128 hlt 129 130blank_idt_ptr: 131 .word 0 /* limit */ 132 .long 0 /* base */ 133 134 .p2align 2 /* force 4-byte alignment */ 135 136multiboot_header: 137 /* magic */ 138 .long 0x1BADB002 139 /* flags */ 140 .long (1 << 16) 141 /* checksum */ 142 .long -0x1BADB002 - (1 << 16) 143 /* header addr */ 144 .long multiboot_header - _x86boot_start + CONFIG_SYS_TEXT_BASE 145 /* load addr */ 146 .long CONFIG_SYS_TEXT_BASE 147 /* load end addr */ 148 .long 0 149 /* bss end addr */ 150 .long 0 151 /* entry addr */ 152 .long CONFIG_SYS_TEXT_BASE 153