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Diffstat (limited to 'arch/x86/cpu/start.S')
| -rw-r--r-- | arch/x86/cpu/start.S | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/arch/x86/cpu/start.S b/arch/x86/cpu/start.S new file mode 100644 index 000000000..7ccc076fe --- /dev/null +++ b/arch/x86/cpu/start.S @@ -0,0 +1,132 @@ +/* + * U-boot - x86 Startup Code + * + * (C) Copyright 2008-2011 + * Graeme Russ, <graeme.russ@gmail.com> + * + * (C) Copyright 2002 + * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se> + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <config.h> +#include <version.h> +#include <asm/global_data.h> +#include <asm/processor-flags.h> + +.section .text +.code32 +.globl _start +.type _start, @function +.globl _x86boot_start +_x86boot_start: + /* + * This is the fail safe 32-bit bootstrap entry point. The + * following code is not executed from a cold-reset (actually, a + * lot of it is, but from real-mode after cold reset. It is + * repeated here to put the board into a state as close to cold + * reset as necessary) + */ + cli + cld + + /* Turn of cache (this might require a 486-class CPU) */ + movl %cr0, %eax + orl $(X86_CR0_NW | X86_CR0_CD), %eax + movl %eax, %cr0 + wbinvd + + /* Tell 32-bit code it is being entered from an in-RAM copy */ + movw $GD_FLG_WARM_BOOT, %bx +_start: + /* This is the 32-bit cold-reset entry point */ + + /* Load the segement registes to match the gdt loaded in start16.S */ + movl $0x18, %eax + movw %ax, %fs + movw %ax, %ds + movw %ax, %gs + movw %ax, %es + movw %ax, %ss + + /* Clear the interupt vectors */ + lidt blank_idt_ptr + + /* Early platform init (setup gpio, etc ) */ + jmp early_board_init +.globl early_board_init_ret +early_board_init_ret: + + /* Initialise Cache-As-RAM */ + jmp car_init +.globl car_init_ret +car_init_ret: + /* + * We now have CONFIG_SYS_CAR_SIZE bytes of Cache-As-RAM (or SRAM, + * or fully initialised SDRAM - we really don't care which) + * starting at CONFIG_SYS_CAR_ADDR to be used as a temporary stack + */ + movl $CONFIG_SYS_INIT_SP_ADDR, %esp + + /* Set parameter to board_init_f() to boot flags */ + xorl %eax, %eax + movw %bx, %ax + + /* Enter, U-boot! */ + call board_init_f + + /* indicate (lack of) progress */ + movw $0x85, %ax + jmp die + +.globl relocate_code +.type relocate_code, @function +relocate_code: + /* + * 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 stack + * %edx = Address of Global Data + * %ecx = Base address of in-RAM copy of U-Boot + */ + + /* Setup stack in RAM */ + movl %eax, %esp + + /* Setup call address of in-RAM copy of board_init_r() */ + movl $board_init_r, %ebp + addl (GD_RELOC_OFF * 4)(%edx), %ebp + + /* Setup parameters to board_init_r() */ + movl %edx, %eax + movl %ecx, %edx + + /* Jump to in-RAM copy of board_init_r() */ + call *%ebp + +die: hlt + jmp die + hlt + +blank_idt_ptr: + .word 0 /* limit */ + .long 0 /* base */ |