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 * See file CREDITS for list of people who contributed to this
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.
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.
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,
31 #include <asm/global_data.h>
32 #include <asm/processor-flags.h>
37 .type _start, @function
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
50 /* Turn of cache (this might require a 486-class CPU) */
52 orl $(X86_CR0_NW | X86_CR0_CD), %eax
56 /* Tell 32-bit code it is being entered from an in-RAM copy */
57 movw $GD_FLG_WARM_BOOT, %bx
59 /* This is the 32-bit cold-reset entry point */
61 /* Load the segement registes to match the gdt loaded in start16.S */
69 /* Clear the interrupt vectors */
72 /* Early platform init (setup gpio, etc ) */
74 .globl early_board_init_ret
77 /* Initialise Cache-As-RAM */
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
86 movl $CONFIG_SYS_INIT_SP_ADDR, %esp
88 /* Set parameter to board_init_f() to boot flags */
95 /* indicate (lack of) progress */
100 .type relocate_code, @function
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
107 * %eax = Address of top of stack
108 * %edx = Address of Global Data
109 * %ecx = Base address of in-RAM copy of U-Boot
112 /* Setup stack in RAM */
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
119 /* Setup parameters to board_init_r() */
123 /* Jump to in-RAM copy of board_init_r() */