[U-Boot] MPC8315 uboot hangs on relocation

[Sureshkumar Nagarathinam]

Hi All, 

I am porting the u-boot for a  customized board based on MPC8315 processor. It has DDR2 SDRAM of 128 MB & 8 MB of flash.  I found that the code hangs during the relocation of the code, exactly in the following line  (@ relocation function in cpu/mpc83xx/start.S) 
             lwz  r5, GOT(__bss_start) 

Since the board has only 8MB of flash, I have modified the the TEXT_BASE to 0xFFF80000(as against 0xFE000000).  I am able to access the DDR2 SDRAM(whole 128MB) , I tested it by writing & reading the patterns 0xaaaaaaaa & 0x555555555, So  I assumed the DDR2 SDRAM timing are proper. 

I would like to know the following 
1. What does the 'GOT(__bss_start) do?
2. Do I have to change the linker script since I have changed the TEXT_BASE? 
3. Is there any other cause for hanging?

Thank you in advance for helping
Regards,
Suresh