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 test %esi, %esi 120 jz skip_hob 121 122 /* Store HOB list */ 123 movl %esp, %edx 124 addl $GD_HOB_LIST, %edx 125 movl %esi, (%edx) 126 127skip_hob: 128#endif 129 /* Setup first parameter to setup_gdt, pointer to global_data */ 130 movl %esp, %eax 131 132 /* Reserve space for global descriptor table */ 133 subl $X86_GDT_SIZE, %esp 134 135 /* Align temporary global descriptor table to 16-byte boundary */ 136 andl $0xfffffff0, %esp 137 movl %esp, %ecx 138 139#if defined(CONFIG_SYS_MALLOC_F_LEN) 140 subl $CONFIG_SYS_MALLOC_F_LEN, %esp 141 movl %eax, %edx 142 addl $GD_MALLOC_BASE, %edx 143 movl %esp, (%edx) 144#endif 145 /* Store BIST */ 146 movl %eax, %edx 147 addl $GD_BIST, %edx 148 movl %ebp, (%edx) 149 150 /* Set second parameter to setup_gdt */ 151 movl %ecx, %edx 152 153 /* Setup global descriptor table so gd->xyz works */ 154 call setup_gdt 155 156 /* Set parameter to board_init_f() to boot flags */ 157 post_code(POST_START_DONE) 158 xorl %eax, %eax 159 160 /* Enter, U-boot! */ 161 call board_init_f 162 163 /* indicate (lack of) progress */ 164 movw $0x85, %ax 165 jmp die 166 167.globl board_init_f_r_trampoline 168.type board_init_f_r_trampoline, @function 169board_init_f_r_trampoline: 170 /* 171 * SDRAM has been initialised, U-Boot code has been copied into 172 * RAM, BSS has been cleared and relocation adjustments have been 173 * made. It is now time to jump into the in-RAM copy of U-Boot 174 * 175 * %eax = Address of top of new stack 176 */ 177 178 /* Stack grows down from top of SDRAM */ 179 movl %eax, %esp 180 181 /* Reserve space on stack for global data */ 182 subl $GENERATED_GBL_DATA_SIZE, %esp 183 184 /* Align global data to 16-byte boundary */ 185 andl $0xfffffff0, %esp 186 187 /* Setup first parameter to memcpy (and setup_gdt) */ 188 movl %esp, %eax 189 190 /* Setup second parameter to memcpy */ 191 fs movl 0, %edx 192 193 /* Set third parameter to memcpy */ 194 movl $GENERATED_GBL_DATA_SIZE, %ecx 195 196 /* Copy global data from CAR to SDRAM stack */ 197 call memcpy 198 199 /* Reserve space for global descriptor table */ 200 subl $X86_GDT_SIZE, %esp 201 202 /* Align global descriptor table to 16-byte boundary */ 203 andl $0xfffffff0, %esp 204 205 /* Set second parameter to setup_gdt */ 206 movl %esp, %edx 207 208 /* Setup global descriptor table so gd->xyz works */ 209 call setup_gdt 210 211 /* Set if we need to disable CAR */ 212.weak car_uninit 213 movl $car_uninit, %eax 214 cmpl $0, %eax 215 jz 1f 216 217 call car_uninit 2181: 219 /* Re-enter U-Boot by calling board_init_f_r */ 220 call board_init_f_r 221 222die: 223 hlt 224 jmp die 225 hlt 226 227blank_idt_ptr: 228 .word 0 /* limit */ 229 .long 0 /* base */ 230 231 .p2align 2 /* force 4-byte alignment */ 232 233multiboot_header: 234 /* magic */ 235 .long 0x1BADB002 236 /* flags */ 237 .long (1 << 16) 238 /* checksum */ 239 .long -0x1BADB002 - (1 << 16) 240 /* header addr */ 241 .long multiboot_header - _x86boot_start + CONFIG_SYS_TEXT_BASE 242 /* load addr */ 243 .long CONFIG_SYS_TEXT_BASE 244 /* load end addr */ 245 .long 0 246 /* bss end addr */ 247 .long 0 248 /* entry addr */ 249 .long CONFIG_SYS_TEXT_BASE 250