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
57 /* This is the 32-bit cold-reset entry point */
59 /* Load the segement registes to match the gdt loaded in start16.S */
67 /* Clear the interrupt vectors */
70 /* Early platform init (setup gpio, etc ) */
72 .globl early_board_init_ret
75 /* Initialise Cache-As-RAM */
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
84 movl $CONFIG_SYS_INIT_SP_ADDR, %esp
86 /* Set parameter to board_init_f() to boot flags */
93 /* indicate (lack of) progress */
98 .type relocate_code, @function
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
105 * %eax = Address of top of stack
106 * %edx = Address of Global Data
107 * %ecx = Base address of in-RAM copy of U-Boot
110 /* Setup stack in RAM */
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
117 /* Setup parameters to board_init_r() */
121 /* Jump to in-RAM copy of board_init_r() */