VxWorks.c ??

Wolfgang Denk wd at denx.de
Thu Jun 12 22:19:00 EST 2003

Dear Mark,

in message <009c01c330d8$425ee3d0$040110ac at junior> you wrote:
> 	I'm trying to reverse-engineer a "home gateway" - used for a home
> automation project I worked on.  It currently runs VxWorks, but I'd like to
> see if I can port Linux to it.  From what I can tell, it's an XPC860 with
> two serial ports, a USB port, a FEC and an Rs-485 port.  It has two FLASH
> chips and two RAM chips - probably 32MB of each.

860 with USB? So there is an external USB controller on the board?

> 	First of all, I need to replace the VxWorks boot loader with U-Boot.
> I have the VxWorks loader capable of loading files from my computer via ftp,
> but the Linux kernel requires virtual memory support, which the boot loader
> doesn't have.  I've looked everywhere for "vxhack.c" and all the ftp sites
> are gone.

I have no doubt that using U-Boot is a Good Thing (TM)  per  se,  but
there  is  no  real  requirement to use it - you can load and start a
Linux kernel using the VxWorks loader, too. You  have  to  tweak  the
Linux  kernel's  bootstrap  loader  code  a  bit, though. There is NO
requirement that the boot loader must support virtual memory - U-Boot
doesn't do this either.

> 	After that, I need to set up a development environment.  I have the
> ppc kernel source, but I'm not able to get libc and u-boot to compile.
> Should I give up and just use the ELDK?  Also, what JTAG Emulators and

It is an interesting experience to go through all steps necessary  to
build  your  own  toolchain and to debug all the funny little details
that can go wrong. But it's time consuming, too. If you just need the
toolchain now, feel free to use the ELDK.

If you want to build your own set  of  tools  please  go  on,  but  I
recommend to separate these two projects ;-)

> programmers do you use that are compatible with Linux and MPC8xx?

The BDI200 was already recommended. I agree with that statement 100%.
On the other hand, the price is a bit high if you need the tool  just
for  a  hobby  project.  For  the MPC8xx you can also use the BDM4GDB
parallel port adapter. Not that powerful, not that fast,  limited  to
8xx  CPUs, not as reliable, plus some other disadvantages if compared
against the BDI2000. But the, you can either build it for  negligible
cost, or buy the ready-to-use adapter for just 50 Euro.

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
Conceptual integrity in turn dictates that the  design  must  proceed
from  one  mind,  or  from  a  very small number of agreeing resonant
minds.               - Frederick Brooks Jr., "The Mythical Man Month"

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