2 * U-boot - i386 Startup Code
4 * Copyright (c) 2002 Omicron Ceti AB, Daniel Engström <denaiel@omicron.se>
6 * See file CREDITS for list of people who contributed to this
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License as
11 * published by the Free Software Foundation; either version 2 of
12 * the License, or (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
28 #include <asm/global_data.h>
29 #include <asm/processor-flags.h>
35 .type _start, @function
36 .globl _i386boot_start
39 * This is the fail safe 32-bit bootstrap entry point. The
40 * following code is not executed from a cold-reset (actually, a
41 * lot of it is, but from real-mode after cold reset. It is
42 * repeated here to put the board into a state as close to cold
48 /* Turn of cache (this might require a 486-class CPU) */
50 orl $(X86_CR0_NW | X86_CR0_CD), %eax
54 /* Tell 32-bit code it is being entered from an in-RAM copy */
55 movw $GD_FLG_WARM_BOOT, %bx
57 /* This is the 32-bit cold-reset entry point */
59 movl $0x18, %eax /* Load our segement registes, the
60 * gdt have already been loaded by start16.S */
67 /* Clear the interupt vectors */
70 /* Skip low-level initialization if not starting from cold-reset */
72 andl $GD_FLG_COLD_BOOT, %ecx
75 /* Early platform init (setup gpio, etc ) */
77 .globl early_board_init_ret
86 /* fetch memory size (into %eax) */
88 .globl get_mem_size_ret
91 #if CONFIG_SYS_SDRAM_ECC_ENABLE
92 /* Skip ECC initialization if not starting from cold-reset */
94 andl $GD_FLG_COLD_BOOT, %ecx
102 /* Check we have enough memory for stack */
103 movl $CONFIG_SYS_STACK_SIZE, %ecx
107 /* Set stack pointer to upper memory limit*/
117 cmpl $0x55aa55aa, %ecx
122 /* Determine our load offset */
127 /* Set the upper memory limit parameter */
128 subl $CONFIG_SYS_STACK_SIZE, %eax
130 /* Reserve space for global data */
131 subl $(GD_SIZE * 4), %eax
133 /* %eax points to the global data structure */
134 movl %esp, (GD_RAM_SIZE * 4)(%eax)
135 movl %ebx, (GD_FLAGS * 4)(%eax)
136 movl %ecx, (GD_LOAD_OFF * 4)(%eax)
138 call board_init_f /* Enter, U-boot! */
140 /* indicate (lack of) progress */