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 /* Tell 32-bit code it is being entered from an in-RAM copy */ 57 movw $GD_FLG_WARM_BOOT, %bx 58_start: 59 /* This is the 32-bit cold-reset entry point */ 60 61 /* Load the segement registes to match the gdt loaded in start16.S */ 62 movl $0x18, %eax 63 movw %ax, %fs 64 movw %ax, %ds 65 movw %ax, %gs 66 movw %ax, %es 67 movw %ax, %ss 68 69 /* Clear the interrupt vectors */ 70 lidt blank_idt_ptr 71 72 /* Early platform init (setup gpio, etc ) */ 73 jmp early_board_init 74.globl early_board_init_ret 75early_board_init_ret: 76 77 /* Initialise Cache-As-RAM */ 78 jmp car_init 79.globl car_init_ret 80car_init_ret: 81 /* 82 * We now have CONFIG_SYS_CAR_SIZE bytes of Cache-As-RAM (or SRAM, 83 * or fully initialised SDRAM - we really don't care which) 84 * starting at CONFIG_SYS_CAR_ADDR to be used as a temporary stack 85 */ 86 movl $CONFIG_SYS_INIT_SP_ADDR, %esp 87 88 /* Set parameter to board_init_f() to boot flags */ 89 xorl %eax, %eax 90 movw %bx, %ax 91 92 /* Enter, U-boot! */ 93 call board_init_f 94 95 /* indicate (lack of) progress */ 96 movw $0x85, %ax 97 jmp die 98 99.globl relocate_code 100.type relocate_code, @function 101relocate_code: 102 /* 103 * SDRAM has been initialised, U-Boot code has been copied into 104 * RAM, BSS has been cleared and relocation adjustments have been 105 * made. It is now time to jump into the in-RAM copy of U-Boot 106 * 107 * %eax = Address of top of stack 108 * %edx = Address of Global Data 109 * %ecx = Base address of in-RAM copy of U-Boot 110 */ 111 112 /* Setup stack in RAM */ 113 movl %eax, %esp 114 115 /* Setup call address of in-RAM copy of board_init_r() */ 116 movl $board_init_r, %ebp 117 addl (GD_RELOC_OFF * 4)(%edx), %ebp 118 119 /* Setup parameters to board_init_r() */ 120 movl %edx, %eax 121 movl %ecx, %edx 122 123 /* Jump to in-RAM copy of board_init_r() */ 124 call *%ebp 125 126die: hlt 127 jmp die 128 hlt 129 130blank_idt_ptr: 131 .word 0 /* limit */ 132 .long 0 /* base */ 133