问题
I have built a custom board with a iMX6 Processor. Unfortunately i have not stripped out the Bootloader Config pins. They are still unconnected BGA-Balls. I do have access to UART1-3, JTAG and SD-Card interface and also to the BOOT0 and BOOT1 pins.
No i would like to start a U-Boot. Therefore i have ported or added my own board to the configs. I can build U-Boot successfull (not tested on the board yet).
Then i thought, i could download u-boot into the internal RAM of the i.MX6. unfortunately the i.MX got only 68kb RAM. The u-boot is about 160kb.
After some googling i saw that there is a possibility to compile a SP-Loader (SPL) which will first start, then load u-boot from SD-Card into the DDR3 RAM and then start the regular U-Boot from external DDR3 RAM.
I also found this readme: https://github.com/ARM-software/u-boot/blob/master/doc/README.SPL
This is my actual defconfig file:
CONFIG_ARM=y
CONFIG_ARCH_MX6=y
CONFIG_TARGET_EVAL1A=y
CONFIG_MXC_UART=y
CONFIG_DM_MMC=y
CONFIG_SYS_TEXT_BASE=0x87800000
CONFIG_SPL_TEXT_BASE=0x0907000
CONFIG_SPL=y
CONFIG_SPL_BUILD=y
CONFIG_SPL_SERIAL_SUPPORT=y
CONFIG_SPL_FS_FAT=y
CONFIG_SPL=y
Im a little bit confused about SYS_TEXT_BASE and SPL_TEXT_BASE. I think SPL_TEXT_BASE is where my SPL will reside? So 907000 is the start of the internal RAM. SYS_TEXT_BASE should be the start of the external DDR3 RAM right?
Anway, with the above config and the following commands:
make mrproper
make myBoard_config
make
I only get the regular u-boot.bin which is about 160kb in size.
What do i wrong? How can i build the SPL into a separate binary?
Thanks.
来源：https://stackoverflow.com/questions/56508485/build-u-boot-spl-for-custom-board