初始化在board_f.c,读取flash环境变量到ddr内在board_r.c

arch/arm/cpu/armv8/start.Sbl	_mainarch/arm/lib/crt0_64.S  xxxxbl	board_init_fxxxxb	board_init_r	commonboard_f.c static const init_fnc_t init_sequence_f[] = {setup_mon_len,arch_cpu_init,		/* basic arch cpu dependent setup */mach_cpu_init,		/* SoC/machine dependent CPU setup */initf_dm,arch_cpu_init_dm,#if defined(CONFIG_BOARD_EARLY_INIT_F)board_early_init_f,#endifenv_init,		/* initialize environment */   //这里初始化环境变量init_baud_rate,		/* initialze baudrate settings */serial_init,		/* serial communications setup */console_init_f,		/* stage 1 init of console */display_options,	/* say that we are here */display_text_info,	/* show debugging info if required */xxxxNULL,};env/env.c int env_init(void){struct env_driver *drv;int ret = -ENOENT;int prio;for (prio = 0; (drv = env_driver_lookup(ENVOP_INIT, prio)); prio++) {if (!drv->init || !(ret = drv->init()))env_set_inited(drv->location);debug("%s: Environment %s init done (ret=%d)\n", __func__,drv->name, ret);}if (!prio)return -ENODEV;if (ret == -ENOENT) {gd->env_addr = (ulong)&default_environment[0];gd->env_valid = ENV_VALID;return 0;}return ret;}include/env_default.h commonboard_r.cstatic init_fnc_t init_sequence_r[] = {#ifdef CONFIG_ARCH_EARLY_INIT_Rarch_early_init_r,#endifpower_init_board,#ifdef CONFIG_MTD_NOR_FLASHinitr_flash,#endifINIT_FUNC_WATCHDOG_RESET#if defined(CONFIG_PPC) || defined(CONFIG_M68K) || defined(CONFIG_X86)/* initialize higher level parts of CPU like time base and timers */cpu_init_r,#endif#ifdef CONFIG_CMD_SFinitr_snor,#endif#ifdef CONFIG_CMD_NANDinitr_nand,#endif#ifdef CONFIG_CMD_ONENANDinitr_onenand,#endif#ifdef CONFIG_MMCinitr_mmc,#endifinitr_env,   //这里重定位环境变量xxxxx#ifdef CONFIG_POSTinitr_post,#endifrun_main_loop,};static int initr_env(void){/* initialize environment */if (should_load_env())env_relocate();elseenv_set_default(NULL, 0);return 0;}env/common.c void env_relocate(void){if (gd->env_valid == ENV_INVALID) {#if defined(CONFIG_ENV_IS_NOWHERE) || defined(CONFIG_SPL_BUILD)/* Environment not changable */env_set_default(NULL, 0);#elsebootstage_error(BOOTSTAGE_ID_NET_CHECKSUM);env_set_default("bad CRC", 0);#endif} else {env_load();     // 这里读环境变量到DDR }}env/sf.c U_BOOT_ENV_LOCATION(sf) = {.location	= ENVL_SPI_FLASH,ENV_NAME("SPI Flash").load		= env_sf_load,#ifdef CMD_SAVEENV.save		= env_save_ptr(env_sf_save),#endif#if defined(INITENV) && (CONFIG_ENV_ADDR != 0x0).init		= env_sf_init,#endif};env_sf_loadret = spi_flash_read(env_flash,CONFIG_ENV_OFFSET, CONFIG_ENV_SIZE, buf);ret = env_import(buf, 1);