Converting to no-bsp

[Ralf Corsepius]

Nick.SIMON at syntegra.bt.co.uk wrote:

> A while ago, it was pointed out that it is possible to build RTEMS library
> without a BSP, and link in the BSP separately.

Yep. What you are refering to, in RTEMS terms is called the bare BSP.

It should not be mixed up with the no_bsp BSP or no_cpu CPU, which are
templates to be used when implementing new BSPs rsp. porting RTEMS to new
CPUs -- They can't even be compiled.

>
> Because we're now using several BSPs with the same processor, I'd like to
> cut down on the amount of space required for multiple RTEMS images, and
> avoid rebuilding the whole kernel whenever a BSP change is made.
>
> Before I plough into this, has anyone any advice?
>

Check the files below c/src/lib/libbsp/bare.

The bare BSP is not enabled by default and can be enabled by adding it to the
list being passed with --enable-rtemsbsps="<list>" at configuration time.
Additionally you need to pass further configuration options to get the
appropriate flags passed into the bare BSP's configuration.

E.g.
configure <more_options> \
--target=sh-rtems \
--enable-rtemsbsp="bare gensh1" \
--enable-bare-cpu-cflags='"-DHZ=40000000 -m1"' \
--enable-bare-cpu-model=sh7032
will configure the sources for the bare bsp for a (fictional) SH1/sh7032 CPU
w/ 40MHz and for the standard gensh1 BSP.

But let me warn you, the bare BSP is in its infancy and not all targets/CPUs
may support it. I know that it can be build for the m68k and the SH, but I
don't know about the status of other targets. Also, setting up the flags can
be cumbersome, but the flags used in make/custom/*.cfg should provide enough
hints to get started.

Ralf

--
Ralf Corsepius
Forschungsinstitut fuer Anwendungsorientierte Wissensverarbeitung (FAW)
Helmholtzstr. 16, 89081 Ulm, Germany     Tel: +49/731/501-8690
mailto:corsepiu at faw.uni-ulm.de           FAX: +49/731/501-999
http://www.faw.uni-ulm.de