[U-Boot] Support of device-tree for PowerPC platform: Query

[Prabhakar Kushwaha]

Hi All,

We are trying to add support of device-tree for PowerPC platforms. As per our analysis following 2 options can be used. 

a) CONFIG_OF_SEPARATE 
b) CONFIG_OF_EMBED

In PowerPC platforms, reset_vector is always expected at the **last** address of flash.  
U-boot binary has reset_vector at last followed by __bss sections(not present in binary) and must be programmed in such a way that reset_vecrot lie at **last** address of flash.  

Hence dtb cannot be appended at last of  u-boot binary.

So there looks to be following 2 possible solutions
a) Use CONFIG_OF_SEPARATE and append dtb at start of u-boot binary.  This require change in flash map because u-boot start address needs to shifted (due to reset_vector requirements).
     Exiting offset of env and fman ucode also needs shifting. This approach requires modification in almost all existing PowerPC platform to adhere to new **modified** flash map.

b) Use CONFIG_OF_EMBED and embed dtb inside u-boot. This way no change in exiting flash map. But its usage is being discouraged as per doc/README.fdt-control.

Please suggest way forward. 

Regards,
Prabhakar