Hello!
loody mil schrieb:
I intend to make a pure uboot, without including any driver but only basic cpu setting and uboot commands supported. But I cannot see any config option in Makefile.
If you need a really minimalistic bootloader U-Boot will not be the first choice. The smallest possible U-Boot will be around 100KByte in size and contain much more than just basic CPU initialisation.
I know I may choose any config in boards and truncate those things I don't need at all.
That's the right way if you want to use U-Boot.
But I send this mail and want to know is there already a config option or some fast way I can meet my requirement?
Nobody knows what are you requirements. If you need a really minimalistic bootloader you should take a look at some sample initialization code from the processor manufacturer.
On certain platforms (e.g. Atmel AT91) even U-Boot will just be used as a second or third level bootloader. The basic CPU setup has been done before starting U-Boot.
With best regards Andreas Schweigstill