一，u-boot编译过程总结

编译时的Makefile log：

//链接得到ELF格式的u-boot
arm-buildroot-linux-gnueabihf-ld.bfd   -pie  --gc-sections -Bstatic -Ttext 0x87800000 -o u-boot -T u-boot.lds arch/arm/cpu/armv7/start.o
--start-group  arch/arm/cpu/built-in.o  arch/arm/cpu/armv7/built-in.o  arch/arm/imx-common/built-in.o  arch/arm/lib/built-in.o  board/freescale/common/built-in.o  board/freescale/mx6ullevk/built-in.o  cmd/built-in.o  
common/built-in.o  disk/built-in.o  drivers/built-in.o  drivers/dma/built-in.o  drivers/gpio/built-in.o  drivers/i2c/built-in.o  drivers/mmc/built-in.o  drivers/mtd/built-in.o  drivers/mtd/onenand/built-in.o  drivers/mtd/spi/built-in.o  
drivers/net/built-in.o  drivers/net/phy/built-in.o  drivers/pci/built-in.o  drivers/power/built-in.o  drivers/power/battery/built-in.o  drivers/power/domain/built-in.o  drivers/power/fuel_gauge/built-in.o  drivers/power/mfd/built-in.o  
drivers/power/pmic/built-in.o  drivers/power/regulator/built-in.o  drivers/serial/built-in.o  drivers/spi/built-in.o  drivers/usb/cdns3/built-in.o  drivers/usb/common/built-in.o  drivers/usb/dwc3/built-in.o  drivers/usb/emul/built-in.o  
drivers/usb/eth/built-in.o  drivers/usb/gadget/built-in.o  drivers/usb/gadget/udc/built-in.o  drivers/usb/host/built-in.o  drivers/usb/musb-new/built-in.o  drivers/usb/musb/built-in.o  drivers/usb/phy/built-in.o  drivers/usb/ulpi/built-in.o  
fs/built-in.o  lib/built-in.o  net/built-in.o  test/built-in.o  test/dm/built-in.o --end-group arch/arm/lib/eabi_compat.o  arch/arm/lib/lib.a -Map u-boot.map


//无设备树的u-boot-nodtb.bin
arm-buildroot-linux-gnueabihf-objcopy --gap-fill=0xff  -j .text -j .secure_text -j .secure_data -j .rodata -j .hash -j .data -j .got -j .got.plt -j .u_boot_list -j .rel.dyn -j .efi_runtime -j .efi_runtime_rel -O binary  u-boot u-boot-nodtb.bin


//编译设备树
make -f ./scripts/Makefile.build obj=dts dtbs
make -f ./scripts/Makefile.build obj=arch/arm/dts dtbs


test -e arch/arm/dts/imx6ull-14x14-evk.dtb || (                        \
echo >&2;                            \
echo >&2 "Device Tree Source is not correctly specified.";    \
echo >&2 "Please define 'CONFIG_DEFAULT_DEVICE_TREE'";        \
echo >&2 "or build with 'DEVICE_TREE=<device_tree>' argument";    \
echo >&2;                            \
/bin/false)


//最终的设备树
  cat arch/arm/dts/imx6ull-14x14-evk.dtb > dts/dt.dtb


//含有设备树的 bin
  cat u-boot-nodtb.bin dts/dt.dtb > u-boot-dtb.bin
make -f ./scripts/Makefile.build obj=arch/arm/imx-common u-boot-dtb.imx
mkdir -p board/freescale/mx6ullevk/
  arm-buildroot-linux-gnueabihf-gcc -E -Wp,-MD,board/freescale/mx6ullevk/.imximage.cfg.cfgtmp.d  -nostdinc -isystem /home/zhuwg1/100ask_imx6ull-sdk/ToolChain/arm-buildroot-linux-gnueabihf_sdk-buildroot/bin/../lib/gcc/arm-buildroot-linux-gnueabihf/7.5.0/include -Iinclude   -I./arch/arm/include -include ./include/linux/kconfig.h -I. -D__KERNEL__ -D__UBOOT__    -D__ARM__ -marm -mno-thumb-interwork  -mabi=aapcs-linux  -mword-relocations  -fno-pic  -mno-unaligned-access  -ffunction-sections -fdata-sections -fno-common -ffixed-r9  -msoft-float   -pipe  -march=armv7-a -D__LINUX_ARM_ARCH__=7     -x c -o board/freescale/mx6ullevk/imximage.cfg.cfgtmp board/freescale/mx6ullevk/imximage.cfg


//制作映像文件 u-boot-dtb.imx
  ./tools/mkimage -n board/freescale/mx6ullevk/imximage.cfg.cfgtmp -T imximage -e 0x87800000 -d u-boot-dtb.bin u-boot-dtb.imx
Image Type:   Freescale IMX Boot Image
Image Ver:    2 (i.MX53/6/7 compatible)
Mode:         DCD
Data Size:    524288 Bytes = 512.00