[U-Boot] [RFC] ARM: U-boot and 2 GiB of ram with get_ram_size only being long

[Oliver Schinagl]

On 10/18/13 22:26, Wolfgang Denk wrote:
> Dear Scott Wood,
>
> In message <1382114601.7979.843.camel at snotra.buserror.net> you wrote:
>>
>> Did you see my other mail in this thread?  This patch is sort of OK for
>> raising the get_ram_size() limit from 1 GiB to 2 GiB (with an increased
>> risk of false positives from I/O), but it can't go beyond that on
>> 32-bit.  A better approach would be to get the RAM size from the memory
>> controller, which is what we do on many Freescale PPC boards.
>
> This is NOT a better approach.  Reading the memory controller just
> tells you what is supposed to be there, i. e. what you programmed into
> the controller.  get_ram_size() shows you what is _actually_ there,
> which may be a totally different thing, for example when different RAM
> chips can be fit on the board, or when the working area of the RAM is
> not the same as the actual chip size, for example due to hardware
> errors (shorts or interruptions on the address lines, etc.).
>
> get_ram_size() is a very efficient memory test that detects 95% or
> more of all RAM related hardware issues.
But is my patch acceptable and does it fix the phys_size_t = long vs 
phys_size_t = unsigned long 'issue'. Does this patch fix that or make it 
worse? And if so, how would that needed to be fixed.

Oliver
>
> Best regards,
>
> Wolfgang Denk
>