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

[Scott Wood]

On Fri, 2013-10-18 at 18:25 -0500, Scott Wood wrote:
> On Sat, 2013-10-19 at 01:07 +0200, Oliver Schinagl wrote:
> > On 10/18/13 18:43, Scott Wood wrote:
> > > On Fri, 2013-10-18 at 02:04 +0200, Oliver Schinagl wrote:
> > >> So now that that's settled, anything fundamentally wrong with my patch? :)
> > >
> > > Did you see my other mail in this thread?  This patch is sort of OK for
> > Sorry I did and I got distracted from it.
> > 
> > > 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
> > I'd ask 'how so' but I'm not sure I'd understand anyway ;)
> 
> Do you mean why it can't go beyond 2 GiB?  The next address to probe
> after 0x8000_0000 would be 0x1_0000_0000 which is beyond what can be
> addressed in a 32-bit environment.  I suppose you could return 4 GiB if
> 0x8000_0000 tests OK, but nothing beyond that.  You'd need a larger
> datatype than "unsigned long" if you want to return 4 GiB, though.

Oh, and if you actually had 4 GiB of RAM mapped in a 32-bit environment,
where would I/O go?

-Scott