Re: [PATCH] [PowerPC] MPC8272ADS: fix device tree for 8 MB flash, size

[Scott Wood <scottwood@freescale.com>]

On Wed, May 13, 2009 at 08:27:07AM +0200, Heiko Schocher wrote:
> Hello Wolfgang,
> 
> > The current device tree for the MPC8272ADS assumes a mapping of 32 MB
> > of NOR flash at 0xFE00.0000, while there are actually only 8 MB on
> > the boards, mapped at 0xFF80.0000. When booting an uImage with such a
> > device tree, the kernel crashes because 0xFE00.0000 is not mapped.
> 
> Wouldn;t it be better, if u-boot fixes the device tree entries?

We should proabbly leave out the ranges altogether, and have u-boot
populate it from the mappings it establishes.

> I think, u-boot should know, where the flash begins and ends, and
> because this is maybe a dynamic variable for this board, it should
> be better, if u-boot fixes this, so no need for adding a device tree
> for every board variant.

Flash is on a SIMM on this board, and the board manual says it's
expandable to 32 MiB.  However, I suspect that the current DTS was just
an error as I based it on a board that had not had its flash SIMM
modified.  That specific flash SIMM is no longer working (or perhaps just
got its contents corrupted -- one of these days I may hook up a BDI and
try to reflash), so I can't go back and check.

I don't see how current u-boot would accomodate more than 8MiB flash on
this board (there's some detection in board/freescale/mpc8260ads/flash.c,
but I don't see any setting of BR0 besides the preliminary value at
0xff800000).

-Scott