Wolfgang Denk wrote:
The problem is that on all of our PowerPC boards, the TLBs only map the lower 2GB of memory, regardless as to how much is present. So we still can't use get_ram_size() to determine how much memory is in the system, because any attempt to access memory higher than 2GB will fail.
Now this is your problem, then, and you should kno how to fix it.
Scott pointed out that writing/reading memory to determine how much memory actually exists is dangerous. I'm not convinced that I should be using get_ram_size(). I still believe that I shouldn't.
And even if we did have TLBs for all of memory, an attempt to access RAM that doesn't exist will cause a machine check, which will hang U-Boot. So we still couldn't use get_ram_size() to determine how much RAM actually exists.
Please see how it's done on all other PowerPC systems, and do similar.
I have not been able to find any other PowerPC system in U-boot that supports more memory than is mapped. If you know of one, please tell me. Otherwise, I would say that there are no other comparable PowerPC systems that I can use as an example.
-long get_ram_size(volatile long *base, long maxsize) +phys_size_t get_ram_size(volatile phys_addr_t *base, phys_size_t maxsize)
I don't think you want 'base' to be a pointer to phys_addr_t, because the pointer type determines how much is read/written in a single operation. I don't think you want to be doing 64-bit reads and writes.
I don't know your mnemory bus. This is an RFC patch.
My point is that sizeof(phys_addr_t) has got nothing to do with the size of the read/write operation, so I think it's wrong on all platforms.