[U-Boot-Users] CFG_MONITOR_BASE < CFG_FLASH_BASE

[Florian Boelstler]

Hi,

yes, it's an old thread -- just for the record:

David Hawkins wrote:
> The MPC8349E can be booted such that the core is held in
> reset, and the processor registers can be configured over
> PCI by another host computer. Therefore it is conceivable
> that the host can program the SDRAM controller on the
> MPC8349E and take the core out of reset. If the core
> is configured to boot from an address mapped to SDRAM,
> then U-Boot could have been copied to SDRAM by the
> host. Once U-Boot boots, it could then use FTP etc
> to boot the kernel blah blah ...
> 
> Yeah yeah, its contrived ...

Not really, we almost do it in that way on a custom MPC8540 and a
MPC8541 board.
Basic hardware settings are done using Boot Sequencer EEPROM.
Settings can be concluded with settings written over PCI by host
(PCSRBAR on BAR0).
U-Boot and Linux are directly written over PCI into RAM.
The boards itself didn't got flash memory at all.
U-Boot environment is contained in I2C-EEPROM as well (can be concluded
with a specially crafted environment found in RAM -- which is another
hack though).

> Of course if the host is configuring all the registers,
> then there is probably no reason for the bootloader ...
> just boot to Linux directly from SDRAM.

No, we don't want to get rid of this nice U-Boot... :)

Cheers,

   Florian