[PATCH V2] ARM: mvebu: fix RAM size for Armada XP board DB-MV784MP-GP

[Jason Cooper]

On Thu, Mar 14, 2013 at 06:22:16PM +0100, Gregory CLEMENT wrote:
> On 03/14/2013 05:56 PM, Jason Cooper wrote:
> > On Thu, Mar 14, 2013 at 10:22:36AM -0600, Jason Gunthorpe wrote:
> >> On Thu, Mar 14, 2013 at 03:57:54PM +0000, Jason Cooper wrote:
> >>> The board is supplied with a 4GB RAM module.  This value can be
> >>> overridden by the bootloader based on probed memory size.  We set it to
> >>> a reasonable value here.
> >>>
> >>> Signed-off-by: Jason Cooper <jason at lakedaemon.net>
> >>> Changes from v1:
> >>>  - grammatical fix suggested by Sergei Shtylyov
> >>>  - correct size suggested by several folks (within 32bit, 1 dword)
> >>>
> >>> As promised, catching this fix in the -rc cycle.
> >>>
> >>> For those not familiar, earlier versions of the patch adding this board listed
> >>> 3GB because that is all that was visible.  I mistaken applied v3 of the patch
> >>> instead of v4 which properly listed 4GB.  This patch cleans up my error.
> >>
> >> What happens when the kernel tries to treat 0xD0000000 and above as
> >> memory? Lots of internal register blocks overlap 0 -> 4GB - won't this
> >> cause resource conflicts on boot? I'm actually very surprised it boots
> >> at all - what does /proc/iomem say?
> > 
> > We'll have to wait to hear from Gregory or Florian on that.  They are
> > the only two I know of who have this board.  I can only compile-test.
> > 
> 
> Indeed there are conflicts with the internals registers. I was too focused
> on the size of the RAM itslelf and I forgotten that if we use the 4GB we have
> no more address space for the internal registers themselves.
> Even with LPAE we will need to leave a "hole" from 0xD0000000 to 0x100000000
> for these registers.
> 
> So to conclude, currently, if we try to boot the Armada XP GP board with
> reg = <0x00000000 0xFFFFFFFF>, the kernel crash, even if there is 4GB of
> RAM.

Ok, so for now, we'll go with <0x00000000 0xD0000000>.

thx,

Jason.