1/* 2 * U-Boot - x86 Startup Code 3 * 4 * (C) Copyright 2008-2011 5 * Graeme Russ, <graeme.russ@gmail.com> 6 * 7 * (C) Copyright 2002 8 * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se> 9 * 10 * SPDX-License-Identifier: GPL-2.0+ 11 */ 12 13#include <config.h> 14#include <asm/global_data.h> 15#include <asm/post.h> 16#include <asm/processor.h> 17#include <asm/processor-flags.h> 18#include <generated/generic-asm-offsets.h> 19#include <generated/asm-offsets.h> 20 21.section .text 22.code32 23.globl _start 24.type _start, @function 25.globl _x86boot_start 26_x86boot_start: 27 /* 28 * This is the fail safe 32-bit bootstrap entry point. The 29 * following code is not executed from a cold-reset (actually, a 30 * lot of it is, but from real-mode after cold reset. It is 31 * repeated here to put the board into a state as close to cold 32 * reset as necessary) 33 */ 34 cli 35 cld 36 37 /* Turn off cache (this might require a 486-class CPU) */ 38 movl %cr0, %eax 39 orl $(X86_CR0_NW | X86_CR0_CD), %eax 40 movl %eax, %cr0 41 wbinvd 42 43 /* Tell 32-bit code it is being entered from an in-RAM copy */ 44 movw $GD_FLG_WARM_BOOT, %bx 45 jmp 1f 46_start: 47 /* 48 * This is the 32-bit cold-reset entry point. Initialize %bx to 0 49 * in case we're preceeded by some sort of boot stub. 50 */ 51 movw $GD_FLG_COLD_BOOT, %bx 521: 53 /* Save BIST */ 54 movl %eax, %ebp 55 56 /* Load the segement registes to match the gdt loaded in start16.S */ 57 movl $(X86_GDT_ENTRY_32BIT_DS * X86_GDT_ENTRY_SIZE), %eax 58 movw %ax, %fs 59 movw %ax, %ds 60 movw %ax, %gs 61 movw %ax, %es 62 movw %ax, %ss 63 64 /* Clear the interrupt vectors */ 65 lidt blank_idt_ptr 66 67 /* Early platform init (setup gpio, etc ) */ 68 jmp early_board_init 69.globl early_board_init_ret 70early_board_init_ret: 71 post_code(POST_START) 72 73 /* Initialise Cache-As-RAM */ 74 jmp car_init 75.globl car_init_ret 76car_init_ret: 77#ifndef CONFIG_HAVE_FSP 78 /* 79 * We now have CONFIG_SYS_CAR_SIZE bytes of Cache-As-RAM (or SRAM, 80 * or fully initialised SDRAM - we really don't care which) 81 * starting at CONFIG_SYS_CAR_ADDR to be used as a temporary stack 82 * and early malloc area. The MRC requires some space at the top. 83 * 84 * Stack grows down from top of CAR. We have: 85 * 86 * top-> CONFIG_SYS_CAR_ADDR + CONFIG_SYS_CAR_SIZE 87 * MRC area 88 * global_data 89 * x86 global descriptor table 90 * early malloc area 91 * stack 92 * bottom-> CONFIG_SYS_CAR_ADDR 93 */ 94 movl $(CONFIG_SYS_CAR_ADDR + CONFIG_SYS_CAR_SIZE - 4), %esp 95#ifdef CONFIG_DCACHE_RAM_MRC_VAR_SIZE 96 subl $CONFIG_DCACHE_RAM_MRC_VAR_SIZE, %esp 97#endif 98#else 99 /* 100 * When we get here after car_init, esp points to a temporary stack 101 * and esi holds the HOB list address returned by the FSP. 102 */ 103#endif 104 105 /* Reserve space on stack for global data */ 106 subl $GENERATED_GBL_DATA_SIZE, %esp 107 108 /* Align global data to 16-byte boundary */ 109 andl $0xfffffff0, %esp 110 post_code(POST_START_STACK) 111 112 /* Zero the global data since it won't happen later */ 113 xorl %eax, %eax 114 movl $GENERATED_GBL_DATA_SIZE, %ecx 115 movl %esp, %edi 116 rep stosb 117 118#ifdef CONFIG_HAVE_FSP 119 /* Store HOB list */ 120 movl %esp, %edx 121 addl $GD_HOB_LIST, %edx 122 movl %esi, (%edx) 123#endif 124 125 /* Setup first parameter to setup_gdt, pointer to global_data */ 126 movl %esp, %eax 127 128 /* Reserve space for global descriptor table */ 129 subl $X86_GDT_SIZE, %esp 130 131 /* Align temporary global descriptor table to 16-byte boundary */ 132 andl $0xfffffff0, %esp 133 movl %esp, %ecx 134 135#if defined(CONFIG_SYS_MALLOC_F_LEN) 136 subl $CONFIG_SYS_MALLOC_F_LEN, %esp 137 movl %eax, %edx 138 addl $GD_MALLOC_BASE, %edx 139 movl %esp, (%edx) 140#endif 141 /* Store BIST */ 142 movl %eax, %edx 143 addl $GD_BIST, %edx 144 movl %ebp, (%edx) 145 146 /* Set second parameter to setup_gdt */ 147 movl %ecx, %edx 148 149 /* Setup global descriptor table so gd->xyz works */ 150 call setup_gdt 151 152 /* Set parameter to board_init_f() to boot flags */ 153 post_code(POST_START_DONE) 154 xorl %eax, %eax 155 156 /* Enter, U-boot! */ 157 call board_init_f 158 159 /* indicate (lack of) progress */ 160 movw $0x85, %ax 161 jmp die 162 163.globl board_init_f_r_trampoline 164.type board_init_f_r_trampoline, @function 165board_init_f_r_trampoline: 166 /* 167 * SDRAM has been initialised, U-Boot code has been copied into 168 * RAM, BSS has been cleared and relocation adjustments have been 169 * made. It is now time to jump into the in-RAM copy of U-Boot 170 * 171 * %eax = Address of top of new stack 172 */ 173 174 /* Stack grows down from top of SDRAM */ 175 movl %eax, %esp 176 177 /* Reserve space on stack for global data */ 178 subl $GENERATED_GBL_DATA_SIZE, %esp 179 180 /* Align global data to 16-byte boundary */ 181 andl $0xfffffff0, %esp 182 183 /* Setup first parameter to memcpy (and setup_gdt) */ 184 movl %esp, %eax 185 186 /* Setup second parameter to memcpy */ 187 fs movl 0, %edx 188 189 /* Set third parameter to memcpy */ 190 movl $GENERATED_GBL_DATA_SIZE, %ecx 191 192 /* Copy global data from CAR to SDRAM stack */ 193 call memcpy 194 195 /* Reserve space for global descriptor table */ 196 subl $X86_GDT_SIZE, %esp 197 198 /* Align global descriptor table to 16-byte boundary */ 199 andl $0xfffffff0, %esp 200 201 /* Set second parameter to setup_gdt */ 202 movl %esp, %edx 203 204 /* Setup global descriptor table so gd->xyz works */ 205 call setup_gdt 206 207 /* Set if we need to disable CAR */ 208.weak car_uninit 209 movl $car_uninit, %eax 210 cmpl $0, %eax 211 jz 1f 212 213 call car_uninit 2141: 215 /* Re-enter U-Boot by calling board_init_f_r */ 216 call board_init_f_r 217 218die: 219 hlt 220 jmp die 221 hlt 222 223blank_idt_ptr: 224 .word 0 /* limit */ 225 .long 0 /* base */ 226 227 .p2align 2 /* force 4-byte alignment */ 228 229multiboot_header: 230 /* magic */ 231 .long 0x1BADB002 232 /* flags */ 233 .long (1 << 16) 234 /* checksum */ 235 .long -0x1BADB002 - (1 << 16) 236 /* header addr */ 237 .long multiboot_header - _x86boot_start + CONFIG_SYS_TEXT_BASE 238 /* load addr */ 239 .long CONFIG_SYS_TEXT_BASE 240 /* load end addr */ 241 .long 0 242 /* bss end addr */ 243 .long 0 244 /* entry addr */ 245 .long CONFIG_SYS_TEXT_BASE 246