]>
Commit | Line | Data |
---|---|---|
2262cfee | 1 | /* |
fea25720 | 2 | * U-boot - x86 Startup Code |
2262cfee | 3 | * |
dbf7115a GR |
4 | * (C) Copyright 2008-2011 |
5 | * Graeme Russ, <graeme.russ@gmail.com> | |
6 | * | |
7 | * (C) Copyright 2002,2003 | |
fa82f871 | 8 | * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se> |
2262cfee WD |
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 | ||
c81b26be | 29 | #include <asm/global_data.h> |
0c24c9cc | 30 | #include <asm/processor-flags.h> |
2262cfee WD |
31 | |
32 | #define BOOT_SEG 0xffff0000 /* linear segment of boot code */ | |
33 | #define a32 .byte 0x67; | |
34 | #define o32 .byte 0x66; | |
35 | ||
36 | .section .start16, "ax" | |
37 | .code16 | |
38 | .globl start16 | |
8bde7f77 | 39 | start16: |
c81b26be GR |
40 | /* Set the Cold Boot / Hard Reset flag */ |
41 | movl $GD_FLG_COLD_BOOT, %ebx | |
42 | ||
8ffb2e8f GR |
43 | /* |
44 | * First we let the BSP do some early initialization | |
2262cfee WD |
45 | * this code have to map the flash to its final position |
46 | */ | |
2262cfee | 47 | jmp board_init16 |
88fa0a6e | 48 | .globl board_init16_ret |
8bde7f77 WD |
49 | board_init16_ret: |
50 | ||
2262cfee | 51 | /* Turn of cache (this might require a 486-class CPU) */ |
53677ef1 | 52 | movl %cr0, %eax |
0c24c9cc | 53 | orl $(X86_CR0_NW & X86_CR0_CD), %eax |
53677ef1 | 54 | movl %eax, %cr0 |
8bde7f77 WD |
55 | wbinvd |
56 | ||
c14a3669 | 57 | /* load the temporary Global Descriptor Table */ |
797960fd | 58 | o32 cs lidt idt_ptr |
53677ef1 | 59 | o32 cs lgdt gdt_ptr |
2262cfee | 60 | |
2262cfee | 61 | /* Now, we enter protected mode */ |
53677ef1 | 62 | movl %cr0, %eax |
0c24c9cc | 63 | orl $X86_CR0_PE, %eax |
53677ef1 | 64 | movl %eax, %cr0 |
8bde7f77 | 65 | |
2262cfee | 66 | /* Flush the prefetch queue */ |
53677ef1 | 67 | jmp ff |
2262cfee | 68 | ff: |
2262cfee | 69 | /* Finally jump to the 32bit initialization code */ |
8bde7f77 | 70 | movw $code32start, %ax |
8ffb2e8f | 71 | movw %ax, %bp |
2262cfee WD |
72 | o32 cs ljmp *(%bp) |
73 | ||
74 | /* 48-bit far pointer */ | |
75 | code32start: | |
53677ef1 WD |
76 | .long _start /* offset */ |
77 | .word 0x10 /* segment */ | |
2262cfee | 78 | |
797960fd GR |
79 | idt_ptr: |
80 | .word 0 /* limit */ | |
81 | .long 0 /* base */ | |
82 | ||
c14a3669 GR |
83 | /* |
84 | * The following Global Descriptor Table is just enough to get us into | |
85 | * 'Flat Protected Mode' - It will be discarded as soon as the final | |
86 | * GDT is setup in a safe location in RAM | |
87 | */ | |
2262cfee | 88 | gdt_ptr: |
c14a3669 | 89 | .word 0x20 /* limit (32 bytes = 4 GDT entries) */ |
53677ef1 | 90 | .long BOOT_SEG + gdt /* base */ |
2262cfee | 91 | |
8bde7f77 | 92 | /* The GDT table ... |
2262cfee | 93 | * |
53677ef1 WD |
94 | * Selector Type |
95 | * 0x00 NULL | |
96 | * 0x08 Unused | |
8bde7f77 | 97 | * 0x10 32bit code |
2262cfee | 98 | * 0x18 32bit data/stack |
2262cfee WD |
99 | */ |
100 | ||
101 | gdt: | |
53677ef1 WD |
102 | .word 0, 0, 0, 0 /* NULL */ |
103 | .word 0, 0, 0, 0 /* unused */ | |
104 | ||
105 | .word 0xFFFF /* 4Gb - (0x100000*0x1000 = 4Gb) */ | |
106 | .word 0 /* base address = 0 */ | |
107 | .word 0x9B00 /* code read/exec */ | |
108 | .word 0x00CF /* granularity = 4096, 386 (+5th nibble of limit) */ | |
109 | ||
110 | .word 0xFFFF /* 4Gb - (0x100000*0x1000 = 4Gb) */ | |
111 | .word 0x0 /* base address = 0 */ | |
112 | .word 0x9300 /* data read/write */ | |
113 | .word 0x00CF /* granularity = 4096, 386 (+5th nibble of limit) */ |