On May 27, 2010, at 3:57 PM, Wolfgang Denk wrote:
Dear Timur Tabi,
In message 4BFECF82.60901@freescale.com you wrote:
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 I point out that we have been doing this for a decade on tens of different board configurations with millions of devices in the field.
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.
The systems I know are the opposite - initially they map more memory than they support, then they determine the real size, then they adjust the mapping to the real size.
Is the point of get_ram_size() to deal with having the same firmware image (binary) be able to be agnostic of memory size?
I'm not sure I understand what utility one gets out of it if we have SPD eeprom information? I can see some purpose in the soldered memory case if you dont want to tweak binaries between different memory size configs.
- k