Hi Jayaraj
I am not sure which SoC/board you are referring
to but as an example for LS1021xTWR board
here is how you can produce it using mainline
u-boot :
make distclean
make ls1021atwr_sdcard_defconfig
make all
with this you would have u-boot-with-spl-pbl.bin
generated and you could boot with this from SD.
Hope this helps
Sinan Akman