[BusyBox] cross compiling

[Robert P. J. Day]

On Wed, 5 May 2004, Wolfgang Denk wrote:

> In message <BDCFDAEC07D52A4ABDAC29167EA2BA6D0155EF77 at OTOCLEX.otomelara.it> you wrote:
> >
> > can someone show me how cross compiling Busybox for PowerPC, from an =
> > Intel target?
> 
> -> wget http://busybox.net/downloads/busybox-1.00-pre10.tar.bz2
> -> tar jxf busybox-1.00-pre10.tar.bz2
> -> cd busybox-1.00-pre10
> -> make config
> ...
> Do you want to build BusyBox with a Cross Compiler? (USING_CROSS_COMPILER) [N/y/?] y
>   Cross Compiler prefix (CROSS_COMPILER_PREFIX) [/usr/i386-linux-uclibc/bin/i386-uclibc-] (NEW) ppc_8xx-
> ...
> -> make

i take a slightly different approach.  i have a project that is 
constructed from numerous pieces -- kernel, busybox, minit, ppp -- and so 
on.  the directory structure looks something like this:

	proj/
		kernel/
		busybox/
		minit/
		ppp/
		...
		Makefile

each software component directory has the following structure:

	busybox/
		makefile
		busybox-configure.sh
		a.config, b.config, c.config, ...
		busybox-1.00-pre8/
		busybox-1.00-pre9/
		busybox-20040427/
		...

and so on.  so, for each generic component (like busybox), i have a 
directory for that component, inside of which i have everything i need to 
compile that component using a choice of config file, which version of the 
software i want and so on -- total flexibility.

each makefile has to define two targets:

	configure:
	install:

for busybox, here's part of the makefile:

	configure:
        	(cd $(SUBDIR) ; \
         	sh ../$(PKG)-configure.sh )

	install:
        	make -C $(SUBDIR) \
                	CROSS=${CROSS_COMPILE} \
                	TARGET_ARCH=${TDEARCH} \
                	install

the configure script is pretty simple:

	cp ../busybox.config ./.config
	yes '' | make oldconfig

so all i need to do is invoke that makefile with the appropriate CROSS
cross-compile value and TARGET_ARCH, and the busybox source will be 
configured and built appropriately.

  one of these days, i'll go back and do some cleaning, but this
structure has worked well so far, and you can appreciate the flexibility.
under my busybox/ directory, for example, i will have as many different 
config files and source trees as i want, and i should always be able to 
select *just* the combination i want for the current build.

  thoughts?

rday

currently, i'm using the ELDK 3.0 cross-compiler, so i'll have
CROSS=ppc_8xx-.