On Thu, Sep 20, 2012 at 3:24 PM, Robert Thorhuus robert.thorhuus@ericsson.com wrote:
I'm using 64 bit mpc85xx cores.
U-Boot runs in 32-bit mode even on a 64-bit code.
Mapping the whole memory from the beginning was of course just an initial thought. But for me it looks like the code is just not able to deal with more than 3.99GB mapped. U-Boot will not be able to be relocated.
I would be very surprised if U-Boot could handle a value of CONFIG_MAX_MEM_MAPPED larger than 2GB, no matter what. We use the address space above 2GB for I/O addresses, like CCSR and PCI memory. You would need to reshuffle your I/O memory mappings to use a larger value. And even then, we've never tested that, and so who knows what obscure bugs are in the code.
Is there a reason why you need access to more than 2GB of RAM from within U-Boot?