[U-Boot] [PATCH] [RFC] memsize.c: adapt get_ram_size() for address spaces >32 bit

[Wolfgang Wegner <wolfgang@leila.ping.de>]

Dear Wolfgang Denk,

as the systems I was working on always had far less memory, I can
not comment much on the extension you propose here, but as Timur
Tabi's comments seem to go in a direction which could lead to a
bigger overhaul/discussion, I would like to add 2C from my point
of view on coldfire...

- MCF53xx/MCF5445x both simply lock up if non-existent memory is
  accessed. So if the SDRAM controller is set up for a too big size
  of memory, get_ram_size() will fail. I assume this applies to
  most coldfire devices.
- How about systems/configurations using CONFIG_MONITOR_IS_IN_RAM?
  I could not see special precautions for this, but in case an address
  to be tested by accident is occupied by a part of get_ram_size()
  itself, the result would be ... interesting. ;-) Of course, this is
  a rare thing (both using CONFIG_MONITOR_IS_IN_RAM and the chance
  to have get_ram_size() at such a crucial location), but still I
  fear it might have an impact if get_ram_size() gets "mandatory".
- at least in the coldfire world, CONFIG_SYS_SDRAM_SIZE is quite
  often used for cache setup in the assembly code. This contradicts
  changing/setting the SDRAM size at runtime...

(Please don't see this as a vote against using and promoting
get_ram_size() - I just see some problems that I am not aware of an
easy solution for.)

Best regards,
Wolfgang Wegner