[U-Boot] Some question about uboot

[Jerry Van Baren]

loody wrote:
> Dear all:
> While porting uboot, I find there are too many things I don't need at
> all, like net, i2c etc.
> How could I remove them from my uboot binary to minimize the size of
> uboot, my flash limitation is 6k?

If 6K is truly what you have, you aren't going to get there with u-boot. 
  I don't know what the current minimum config results in (and it will 
vary depending on processor and the definition of "minimum"), but rule 
of thumb is that 128K is a fairly tight u-boot; under 128K and you will 
be cutting deeply.  It may be possible to get it under 64K with a lot of 
work, but it may be easier to start with a different code base or start 
from scratch.

Can you do a two level bootstrap where you have a 6K minimal bootstrap 
program that loads u-boot from somewhere else that has 128K-256K 
available?  Note that this is what NAND-booting systems (e.g. ARM) do - 
the NAND first stage boot fits in 4K, the rest gets copied from NAND to 
RAM and then run in RAM.

> I try to edit Makefile to remove them by marking some library setting,
> but it compile error after I doing so.

Libraries are crack cocaine to programmers.  Once you use them, it is 
really hard to give them up.  :-)

> Is there any easier way to meet my requirement?

Sorry, unless there is a really significant typo in your original email, 
u-boot has way too much functionality for your constraints.  I don't 
know what the alternatives are (there are some), but you are looking at 
a very tight boot ROM probably written mostly/entirely in assembly or 
very constrained C (no libraries, very tightly written, max optimization).

> Appreciate your help,
> miloody

Good luck,
gvb