tree a94bffe91400f0486571454a3db56733899c4c7e
parent 182c82b484c6d8a275715656358e24a85bc812f5
author Rick Chen <rick@andestech.com> 1522289313 +0800
committer Andes <uboot@andestech.com> 1522386836 +0800

riscv: ae250: Support DT provided by the board at runtime

Enable CONFIG_OF_BOAD to support delivery dtb to u-boot
at run time instead of embedded.

There are two methods to delivery dtb.
 1 Pass from loader:
   When u-boot boot from RAM, gdb or loader can pass dtb
   via a2 to u-boot dynamically. Of course gdb or loader
   shall be in charge of dtb delivery.

 2 Configure CONFIG_SYS_FDT_BASE:
   It can be configured as RAM or ROM base statically,
   no mater u-boot boot from RAM or ROM.
   If it was configured as ROM base, dtb can be burned
   into ROM(spi flash) by spi driver.

Meanwhile remove CONFIG_SKIP_LOWLEVEL_INIT which is
useless in nx25-ae250 configuration.

Signed-off-by: Rick Chen <rick@andestech.com>
Signed-off-by: Rick Chen <rickchen36@gmail.com>
Cc: Greentime Hu <green.hu@gmail.com>