[U-Boot] Some question about uboot

[loody]

Hi Jerry:

2009/2/24 Jerry Van Baren <gerald.vanbaren at ge.com>:
> 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.
Thanks for your kind suggestion.
If I only need uboot to do cpu basic setting with USB ehci and file
system support, does it still need 128k at least?
As you suggest, I can do the 2 levels bootstrap.
But uboot has great features support.
I am not sure it will be easier to make another wheel.

> 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).

Would you please tell me how to add a new cpu and platform in uBoot?
I know the first step I have to do is adding my cpu and platform
folder. But I have no idea how to add setting in Makefile.
why sometimes we use "@$(MKCONFIG) $(@:_config=)" ,sometimes we use
"@$(MKCONFIG) -a" and sometimes we have to " @mkdir -p $(obj)include"
before calling mkconfig?

I try to modify platform.h located at include/configs to remove
unnecessary driver.
But I have no idea which one I can remove such that the unnecessary
driver will no compile my uboot.
for example, I remove "CONFIG_DRIVER_CS8900" in smdk2410.h, and the
error message while linking is "net/libnet.a(net.o): In function
`NetSendPacket':
/media/u-boot_20090224_snapshot/net/net.c:654: undefined reference to
`eth_send'"
Appreciate your kind help,
miloody

I

I want to add my cpu and platform and find out where the bottle net is.