DRAM Address range for user defined data

Hi,

I would like to use 4KB of memory in DRAM for user data. This will be written in uboot and will be read in Kernel. What is the range of addresses that can be used for this purpose?

Thanks for the response in advance.

car_info in uboot (arch/arm/mach-tegra/nvtboot.c) has the info about how the memory is used by the boot binary prior to uboot.