1、内核等固件加载地址：ENV_MEM_LAYOUT_SETTINGS，定义如下
./include/configs/rk3399_common.h
58 #define ENV_MEM_LAYOUT_SETTINGS \
59 "scriptaddr=0x00500000\0" \
60 "pxefile_addr_r=0x00600000\0" \
61 "fdt_addr_r=0x08300000\0" \
62 "kernel_addr_r=0x00280000\0" \
63 "ramdisk_addr_r=0x0a200000\0"
uboot启动log如下：
Booting IMAGE kernel at 0x00280000 with fdt at 0x8300000...
2、PARTS_DEFAULT：默认的GPT分区
include/configs/rockchip-common.h
85 #define PARTS_DEFAULT \
86 "uuid_disk=${uuid_gpt_disk};" \
87 "name=loader1,start=32K,size=4000K,uuid=${uuid_gpt_loader1};" \
88 "name=loader2,start=8MB,size=4MB,uuid=${uuid_gpt_loader2};" \
89 "name=trust,size=4M,uuid=${uuid_gpt_atf};" \
90 "name=boot,size=112M,bootable,uuid=${uuid_gpt_boot};" \
91 "name=rootfs,size=-,uuid="ROOT_UUID
3、ROCKCHIP_DEVICE_SETTINGS 外设相关命令，主要是指定 stdio（一般会包含显示模块启动命
令）
include/configs/evb_rk3399.h
29 #define ROCKCHIP_DEVICE_SETTINGS \
30 "stdout=serial,vidconsole\0" \
31 "stderr=serial,vidconsole\0"
4、BOOTENV：distro 方式启动 linux 时的启动设备探测命令
include/config_distro_bootcmd.h
315 #define BOOTENV \
316 BOOTENV_SHARED_HOST \
317 BOOTENV_SHARED_MMC \
318 BOOTENV_SHARED_PCI \
319 BOOTENV_SHARED_USB \
320 BOOTENV_SHARED_SATA \
321 BOOTENV_SHARED_SCSI \
322 BOOTENV_SHARED_IDE \
323 BOOTENV_SHARED_UBIFS \
324 BOOTENV_SHARED_EFI \
325 "boot_prefixes=/ /boot/\0" \
326 "boot_scripts=boot.scr.uimg boot.scr\0" \
327 "boot_script_dhcp=boot.scr.uimg\0" \
328 BOOTENV_BOOT_TARGETS \
329 \
330 "boot_extlinux=" \
331 "sysboot ${devtype} ${devnum}:${distro_bootpart} any " \
332 "${scriptaddr} ${prefix}extlinux/extlinux.conf\0" \
333 \
334 "scan_dev_for_extlinux=" \
335 "if test -e ${devtype} " \
336 "${devnum}:${distro_bootpart} " \
337 "${prefix}extlinux/extlinux.conf; then " \
338 "echo Found ${prefix}extlinux/extlinux.conf; " \
339 "run boot_extlinux; " \
340 "echo SCRIPT FAILED: continuing...; " \
341 "fi\0" \
342 \
343 "boot_a_script=" \
344 "load ${devtype} ${devnum}:${distro_bootpart} " \
345 "${scriptaddr} ${prefix}${script}; " \
346 "source ${scriptaddr}\0" \
347 \
348 "scan_dev_for_scripts=" \
349 "for script in ${boot_scripts}; do " \
350 "if test -e ${devtype} " \
351 "${devnum}:${distro_bootpart} " \
352 "${prefix}${script}; then " \
353 "echo Found U-Boot script " \
354 "${prefix}${script}; " \
355 "run boot_a_script; " \
356 "echo SCRIPT FAILED: continuing...; " \
357 "fi; " \
358 "done\0" \
359 \
360 "scan_dev_for_boot=" \
361 "echo Scanning ${devtype} " \
362 "${devnum}:${distro_bootpart}...; " \
363 "for prefix in ${boot_prefixes}; do " \
364 "run scan_dev_for_extlinux; " \
365 "run scan_dev_for_scripts; " \
366 "done;" \
367 SCAN_DEV_FOR_EFI \
368 "\0" \
369 \
370 "scan_dev_for_boot_part=" \
371 "part list ${devtype} ${devnum} -bootable devplist; " \
372 "env exists devplist || setenv devplist 1; " \
373 "for distro_bootpart in ${devplist}; do " \
374 "if fstype ${devtype} " \
375 "${devnum}:${distro_bootpart} " \
376 "bootfstype; then " \
377 "run scan_dev_for_boot; " \
378 "fi; " \
379 "done\0" \
380 \
381 BOOT_TARGET_DEVICES(BOOTENV_DEV) \
382 \
383 "distro_bootcmd=" BOOTENV_SET_SCSI_NEED_INIT \
384 "for target in ${boot_targets}; do " \
385 "run bootcmd_${target}; " \
386 "done\0"
5、CONFIG_SYS_MALLOC_LEN：malloc 内存池大小
include/config_distro_bootcmd.h
#define CONFIG_SYS_MALLOC_LEN (192 << 20)
6、CONFIG_SYS_TEXT_BASE：U-Boot 运行的起始地址
#define CONFIG_SYS_TEXT_BASE 0x00200000
7、CONFIG_BOOTCOMMAND：启动命令，一般定义为 RKIMG_BOOTCOMMAND
include/configs/rockchip-common.h
128 #ifdef CONFIG_AVB_VBMETA_PUBLIC_KEY_VALIDATE
129 #define RKIMG_BOOTCOMMAND \
130 "boot_android ${devtype} ${devnum};" \
131 "echo AVB boot failed and enter rockusb or fastboot!;" \
132 "rockusb 0 ${devtype} ${devnum};" \
133 "fastboot usb 0;"
134 #else
135 #define RKIMG_BOOTCOMMAND \
136 "boot_android ${devtype} ${devnum};" \
137 "bootrkp;" \
138 "run distro_bootcmd;"
139 #endif
140 #endif
8、CONFIG_PREBOOT：预启动命令，在 CONFIG_BOOTCOMMAND 前被执行
9、CONFIG_SYS_MMC_ENV_DEV：MMC 作为 ENV 存储介质时的 dev num，一般是 0
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