[U-Boot-Users] Can U-Boot be divided into TWO stages

[Wolfgang Denk]

In message <OF7269A263.F3284F70-ON48256EB2.0013759A at legend.com.cn> you wrote:
>                                                                              
> As I would not use any NOR Flash on   
> my project, U-Boot and                
> Linux Kernel are both seated on the   
> NAND Flash. The bootrom               
> can boot only a piece of code not     
> more than 16K, so I must              
> cut U-Boot down to 16k or divide it   
> into two stages (like GRUB).          

This is not (easily) possible. The whole design of U-Boot is based on
the assumption that we can call C code (including the needed  library
routines)  as  early  after power-on as possible. Even before initia-
lizing the memory controller we arrange  for  a  serial  console  and
messages printed to the console. All this does not fit in 16 kB.

You could use your own botstrap code which  performs  enough  of  the
necessary  hardware  intiialization, and which then could load a full
U-Boot image (whih the relkevant initialization parts disabled)  form
NAND flash - but to do so you would have to implement your own simple
boot loader.

It can be done, but it includes a lot of work and I doubt it if makes
sense.

U-Boot was not designed for this, and we don't plan to support such a
configuration.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
There is nothing in this world constant but inconstancy.      - Swift