Starterware: SPL(U-boot 2013) crashed!

Tool/software: Starterware

Hi !  TI experts:

      We using AM335X and psp4.6.0.0.11 to my project, and it works very fine.

      Recently,SPL has been crashed in our a new batch of core modules.

      We found the SPL  hangs in spl_board_init -> gpmc_init -> writel(0x00000008, &gpmc_cfg->sysconfig), 

      We have been unable to locate where the problem occurred , nand or ddr?

      any ideas?

      thanks very mach!