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 34.section .text 35.code32 36.globl _start 37.type _start, @function 38.globl _x86boot_start 39_x86boot_start: 40 /* 41 * This is the fail safe 32-bit bootstrap entry point. The 42 * following code is not executed from a cold-reset (actually, a 43 * lot of it is, but from real-mode after cold reset. It is 44 * repeated here to put the board into a state as close to cold 45 * reset as necessary) 46 */ 47 cli 48 cld 49 50 /* Turn of cache (this might require a 486-class CPU) */ 51 movl %cr0, %eax 52 orl $(X86_CR0_NW | X86_CR0_CD), %eax 53 movl %eax, %cr0 54 wbinvd 55 56_start: 57 /* This is the 32-bit cold-reset entry point */ 58 59 /* Load the segement registes to match the gdt loaded in start16.S */ 60 movl $0x18, %eax 61 movw %ax, %fs 62 movw %ax, %ds 63 movw %ax, %gs 64 movw %ax, %es 65 movw %ax, %ss 66 67 /* Clear the interrupt vectors */ 68 lidt blank_idt_ptr 69 70 /* Early platform init (setup gpio, etc ) */ 71 jmp early_board_init 72.globl early_board_init_ret 73early_board_init_ret: 74 75 /* Initialise Cache-As-RAM */ 76 jmp car_init 77.globl car_init_ret 78car_init_ret: 79 /* 80 * We now have CONFIG_SYS_CAR_SIZE bytes of Cache-As-RAM (or SRAM, 81 * or fully initialised SDRAM - we really don't care which) 82 * starting at CONFIG_SYS_CAR_ADDR to be used as a temporary stack 83 */ 84 movl $CONFIG_SYS_INIT_SP_ADDR, %esp 85 86 /* Set parameter to board_init_f() to boot flags */ 87 xorl %eax, %eax 88 movw %bx, %ax 89 90 /* Enter, U-boot! */ 91 call board_init_f 92 93 /* indicate (lack of) progress */ 94 movw $0x85, %ax 95 jmp die 96 97.globl relocate_code 98.type relocate_code, @function 99relocate_code: 100 /* 101 * SDRAM has been initialised, U-Boot code has been copied into 102 * RAM, BSS has been cleared and relocation adjustments have been 103 * made. It is now time to jump into the in-RAM copy of U-Boot 104 * 105 * %eax = Address of top of stack 106 * %edx = Address of Global Data 107 * %ecx = Base address of in-RAM copy of U-Boot 108 */ 109 110 /* Setup stack in RAM */ 111 movl %eax, %esp 112 113 /* Setup call address of in-RAM copy of board_init_r() */ 114 movl $board_init_r, %ebp 115 addl (GD_RELOC_OFF * 4)(%edx), %ebp 116 117 /* Setup parameters to board_init_r() */ 118 movl %edx, %eax 119 movl %ecx, %edx 120 121 /* Jump to in-RAM copy of board_init_r() */ 122 call *%ebp 123 124die: hlt 125 jmp die 126 hlt 127 128blank_idt_ptr: 129 .word 0 /* limit */ 130 .long 0 /* base */ 131