[ECOS] Creating a drop in replacement for the pcmb package

[Ian Campbell <icampbell at arcom dot co dot uk>]

Hi,

I would like to create a drop in replacement for the pcmb package to
support one of our products and would like some advice on a couple of
matters.

My first problem is that the pcmb header files are hard coded in several
places in the pc package. 

I have attempted to work some magic in the CDL files by making the name
of the header files a set of cdl_options but I had to jump through some
hoops and it seems rather ugly to me.

Perhaps the correct path would be to define a cdl_interface something
like CYGHWR_HAL_I386_PC_MOTHERBOARD and require it from the pc package
and provide it in the pcmb and merlin packages, then rename the merlin
header files to have the same names as their pcmb counterparts (and use
define_header to rename the config header).

Maybe someone has a better idea, or can tell me what the preferred
solution is, to give maximum chance of acceptance for whatever patches I
need to pass upstream?

My second query is to do with romboot.S which currently resides in
hal/i386/arch. Unfortunately the merlin boards do not have exactly the
same boot sequence, although they are fairly similar. I don't think I
can override which files are compiled in another module with my own, so
I think that either romboot.S really belongs in pcmb or else some level
of abstraction could be added, for example factoring out some
functionality into macros such as hal_i386_setup_gdt,
hal_i386_setup_mem, etc in pcmb/merlin packages. I would be happy to do
the work necessary to factor these things out.

My third question is about the memory layout files (pc package
include/pkgconf/mlt_i386_pc_rom.{h,ldi}). Again I need to override
these. They claim to be generated, but I gather this is by the config
tool rather than at build time from cdl options. Since these are header
files, can I simply include my own copies in the merlin package and
arrange for these to go into the build tree in preference to the ones in
the pc package? or otherwise influence the values of
CYGHWR_MEMORY_LAYOUT_{LDI,H} from the merlin cdl file? Perhaps these
files are another candidate for moving to pcmb?

Sorry for the long mail, but I thought it would be better to go through
it all in one go.

Thanks in advance, especially for any advice with regard to what would
be most acceptable to upstream.

Regards,
Ian.

-- 
Ian Campbell
Design Engineer

Arcom Control Systems Ltd,
Clifton Road,
Cambridge CB1 7EA
United Kingdom

Tel: +44 (0)1223 411200 ext. 3204
E-Mail: icampbell@arcom.co.uk
Web: http://www.arcomcontrols.com


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