1./u-boot-2019.07/Kconfig 是顶层Kconfig
mainmenu "U-Boot $UBOOTVERSION Configuration" #这是总menu
2.source "arch/Kconfig" #然后就引用了arch目录下的Kconfig 这个Kconfig中可以选择不同的架构，有arm M68K MIPS等
choice
prompt "Architecture select"
default SANDBOX
config ARC
bool "ARC architecture"
select ARCH_EARLY_INIT_R
select ARC_TIMER
select CLK
select HAVE_PRIVATE_LIBGCC
select SUPPORT_OF_CONTROL
select TIMER
config ARM
bool "ARM architecture"
select CREATE_ARCH_SYMLINK
select HAVE_PRIVATE_LIBGCC if !ARM64
select SUPPORT_OF_CONTROL
config M68K
bool "M68000 architecture"
select HAVE_PRIVATE_LIBGCC
select SYS_BOOT_GET_CMDLINE
select SYS_BOOT_GET_KBD
select SUPPORT_OF_CONTROL
config MICROBLAZE
bool "MicroBlaze architecture"
select SUPPORT_OF_CONTROL
imply CMD_IRQ
.
.
.
source "arch/arc/Kconfig"
source "arch/arm/Kconfig"
source "arch/m68k/Kconfig"
source "arch/microblaze/Kconfig" #最后引入了各个架构目录下的Kconfig
3./u-boot-2019.07/arch/arm/Kconfig
menu "ARM architecture"
depends on ARM
config SYS_ARCH
default "arm" #这里定义了CONFIG_SYS_ARCH
config CPU_V7A
bool
select HAS_THUMB2
select HAS_VBAR
select SYS_CACHE_SHIFT_6
imply SYS_ARM_MMU #CPU_V7A还会选择一些宏定义开
config SYS_CPU
default "arm720t" if CPU_ARM720T
default "arm920t" if CPU_ARM920T
default "arm926ejs" if CPU_ARM926EJS
default "arm946es" if CPU_ARM946ES
default "arm1136" if CPU_ARM1136
default "arm1176" if CPU_ARM1176
default "armv7" if CPU_V7A
default "armv7" if CPU_V7R
default "armv7m" if CPU_V7M
default "pxa" if CPU_PXA
default "sa1100" if CPU_SA1100
default "armv8" if ARM64 #这里定义了CONFIG_SYS_CPU（需要预先定义CPU_V7A）
choice
prompt "Target select"
default TARGET_HIKEY
config ARCH_S5PC1XX
bool "Samsung S5PC1XX"
select CPU_V7A
select DM
select DM_GPIO
select DM_I2C
select DM_SERIAL
imply CMD_DM
config ARCH_ZYNQ
bool "Xilinx Zynq based platform"
select BOARD_EARLY_INIT_F if WDT
select CLK
select CLK_ZYNQ
select CPU_V7A
select DM
select DM_ETH if NET
select DM_MMC if MMC
select DM_SERIAL
select DM_SPI
select DM_SPI_FLASH
select DM_USB if USB
select OF_CONTROL
select SPI
select SPL_BOARD_INIT if SPL
select SPL_CLK if SPL
select SPL_DM if SPL
select SPL_OF_CONTROL if SPL
select SPL_SEPARATE_BSS if SPL
select SUPPORT_SPL
imply ARCH_EARLY_INIT_R
imply BOARD_LATE_INIT
imply CMD_CLK
imply CMD_DM
imply CMD_SPL
imply FAT_WRITE #在这里选择了CPU_V7A ARCH_S5PC1XX ARCH_ZYNQ在menuconfig中选中即定义了。
source "arch/arm/mach-s5pc1xx/Kconfig"
source "arch/arm/mach-zynq/Kconfig" #如果有mach需要将Kconfig加入
好像并没有包含source "board/samsung/goni/Kconfig"
source "board/xilinx/zynq/Kconfig" #将board中的Kconfig加入
4.arch/arm/mach-s5pc1xx/Kconfig 答案在这里，s5pc1xx下有两个board需要选择，这其中包含了source "board/samsung/goni/Kconfig"，所以每家公司的代码风格不大一样。
if ARCH_S5PC1XX
choice
prompt "S5PC1XX board select"
optional
config TARGET_S5P_GONI
bool "S5P Goni board"
select OF_CONTROL
select BLK
select DM_MMC #选中goni board
config TARGET_SMDKC100
bool "Support smdkc100 board"
select OF_CONTROL
endchoice
config SYS_SOC
default "s5pc1xx"
source "board/samsung/goni/Kconfig"
source "board/samsung/smdkc100/Kconfig"
endif
5.arch/arm/mach-zynq/Kconfig #定义了SYS_BOARD等 而s5pc1xx不是在这里定义的。
if ARCH_ZYNQ
config SPL_LDSCRIPT
default "arch/arm/mach-zynq/u-boot-spl.lds"
config SYS_BOARD
string "Board name"
default "zynq"
config SYS_VENDOR
string "Vendor name"
default "xilinx"
config SYS_SOC
default "zynq"
endif
6.board/samsung/goni/Kconfig #定义了SYS_BOARD等 在arch/arm/mach-s5pc1xx/Kconfig下一层因为if TARGET_S5P_GONI是 arch/arm/mach-s5pc1xx/Kconfig中选定的
if TARGET_S5P_GONI
config SYS_BOARD
default "goni"
config SYS_VENDOR
default "samsung"
config SYS_SOC
default "s5pc1xx"
config SYS_CONFIG_NAME
default "s5p_goni"
endif
7.board/xilinx/zynq/Kconfig 和arch/arm/mach-zynq/Kconfig 感觉平行层级 都用的if ARCH_ZYNQ
# SPDX-License-Identifier: GPL-2.0
#
# Copyright (c) 2018, Xilinx, Inc.
if ARCH_ZYNQ
config CMD_ZYNQ
bool "Enable Zynq specific commands"
default y
help
Enables Zynq specific commands.
config CMD_ZYNQ_AES
bool "Enable zynq aes command for decryption of encrypted images"
depends on CMD_ZYNQ
depends on FPGA_ZYNQPL
help
Decrypts the encrypted image present in source address
and places the decrypted image at destination address.
config CMD_ZYNQ_RSA
bool "Enable zynq rsa command for loading secure images"
default y
depends on CMD_ZYNQ
depends on CMD_ZYNQ_AES
help
Enabling this will support zynq secure image verification.
The secure image is a xilinx specific BOOT.BIN with
either authentication or encryption or both encryption
and authentication feature enabled while generating
BOOT.BIN using Xilinx bootgen tool.
endif
在Kconfig体系结构中，可以明显看到这样一个顺序
ARCH arm