[ECOS] Porting Redboot and eCos to mpc8536ds CPU on Custom SBC

["Steve Penner" <stephenpenner at comcast dot net>]

This request for help is intended for the "ecos-discuss" list:

I would like to port eCos and Redboot to a custom-built single-board
computer that uses a powerpc-e500v2 CPU (specifically, the mpc8536ds)
running at 1 GHz. The board has a 512 MB of SDRAM, 3 RS232 ports, 4 RS485
ports, a standalone Dallas Semi RTC, and a fairly large complement of other
peripherals, including an ARM co-processor that controls access to analog
and digital I/O.

Currently, the soldered-in boot-ROM contains u-boot (a mildly customized
spin of version 2009.11), which boostraps into a Linux 2.6.34 kernel (from
kernel.org, with no customizations) located on a removable 512-MB CF card.
Most utilities and other apps reside on that CF card, and are from
MonteVista Linux.

The u-boot/Linux configuration works adequately for most non-realtime
purposes, but I would like to see if I can substantially improve performance
of data acquisition and control applications by moving to Redboot/eCos.

>From my reading and experiments thus far, it looks like this might be a
reasonable general outline for porting Redboot/eCos:

(1) Set up eCos dev environment on my Ubuntu host machine. (Currently 10.04,
but I could upgrade to 12.04, or whatever, to improve the dev process). I
have downloaded and installed the latest eCos.

(2) Modify the "architecture" and "platform" elements of the HAL source and
config files to reflect the as-yet unsupported mpc8536ds architecture and
the custom platform. It appears that the eCos docs include some hints on
this process, but also warn that it can consume a lot of time... It seems
like this step should yield .cdl, .c, .h, and .ecm files (right?).

(3) Use the generated HAL files to re-build Redboot. Is one of the GNU
powerpc C compilers that comes with the latest eCos distro adequate for the
mpc8536ds, or do I need to obtain a different compiler? If the former, which
one? If the latter, what do I need to do to configure a third-party compiler
for use with Redboot and eCos?

(4) Debug/development cycle:
(a) Boot into u-boot.
(b) tftp redboot_RAM.bin into RAM.
(c) Run Redboot in RAM.
(d) Test Redboot.
(e) Power cycle the hardware when necessary.
(f) Eventually, program Redboot into ROM.

(4) Build eCos using previously-generated or -obtained HAL files, compiler,
linker, etc.

And herewith my questions:

(1) Does this approach sound like it has a better-than-even chance of
success, assuming average embedded programming and hardware dev skills on my
part?

(2) Has anyone already done any of this work for the mpc8536ds?

(3) Does anyone have any suggestions for jump-starting the work?

Thank you very much for any help you can provide!

-Steve


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