[U-Boot-Users] Memory layout on PXA

Robert Schwebel robert at schwebel.de
Wed Feb 12 20:07:35 CET 2003

Hi Geir, 

On Wed, Feb 12, 2003 at 07:40:27PM +0100, Geir Thomassen wrote:
> I am porting u-boot to a custom PXA255 board.

I've recently sent several patches to Wolfgang for the PXA architecture;
unfortunately he didn't have time to integrate them yet. If I don't
forget it I can send you my patches against current CVS tomorrow. 

> 1) u-boot is copied from flash into memory at TEXT_BASE
> (typ. 0xA3000000 on PXA).


> 2) The stack is below the u-boot code. From cpu/xscale/start.S,
> it looks like the stack is at TEXT_BASE - CFG_MALLOC_LEN - 12. I
> think the stack grows toward lower addresses on arm, is this
> correct ?

In ARMboot the stack was above the relocated uboot code - I tried to
change this for my PXA250 implementation. I know that there are code
fragments left which assume that the stack is above - this is partly
fixed in the patches I sent to Wolfgang. 

> 3) Memory for malloc() is supposed to be after the u-boot
> code (including initialized and initialized data) at address
> armboot_real_end.

Not in my ports (CSB226, Innokom). I tried to follow the way which is
outlined in the README document. 

> BTW: Does u-boot run "out of the box" on any PXA hardware, I
> don't understand how it could unless the hardware have RAM at
> 0xBADC0DE ..

At the moment I have it running on the plattforms mentioned above. If
you don't get my patch tomorrow in the morning please ask back... 


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