[wplug] uCLinux

[Weber, Larry A]

I have a Freescale Eval board for the 5235 Coldfire, based on the V2 core.
I have been doing embedded development for 25+ years but have only had one,
bad, experience using Linux as an embedded OS.  I thought this might be a
good opportunity to learn a little more about the Linux OS and see if it
could be used in future product designs.  I talked to a Freescale Rep. who
says that uClinux is already available for this board but not currently
posted.  He hopes to have more info soon.  Thanks for your responses.

> -----Original Message-----
> From:	wplug-bounces+laweber=switch.com at wplug.org
> [SMTP:wplug-bounces+laweber=switch.com at wplug.org] On Behalf Of Michael M
> Delaney
> Sent:	Friday, October 08, 2004 11:50 AM
> To:	General user list
> Subject:	Re: [wplug] uCLinux
> 
> I may have asked part of this before, but I don't rembember getting the
> answer.
> If you are looking to just do the porting as kind of a "fun" project, but
> haven't ever done embedded development and uClinux development, I would
> strongly suggest first getting a supported Coldfire board (then again, I
> don't know how much they cost) first, and learning some of the ins and
> outs of both Coldfire and uClinux.  Check the mailing list for
> Coldfire, and see if anyone has started work on the port.  And check
> uCdot, in particular http://www.ucdot.org/search.pl?topic=9 is a list of
> deve boards people have submitted.  (Thats assuming you don't have a
> board, and don't already have a specific one in mind, but it may still be
> worth a look).
> 
> Mike
> 
> 
> On Thu, 7 Oct 2004, Darin Ingimarson wrote:
> 
> > Weber, Larry A wrote:
> >
> > >Freescale (Motorola) has recently released several new Coldfire
> processors (MCP523x) and an evaluation board.  I thought it might be a
> good learning experience to try to port uCLinux to the board.
> > >
> > Yeah, it would definately be a learning experience for you ;-)
> >
> >  From my experience in porting RTOS's (probably applicable to general
> > embedded OS ports), the most frustrating part will involve setting up
> > the initial cross-developmnet platfom and toolchain. This is not
> > entirely trivial, and you need to make sure that your processor of
> > interest is supported by your compiler. Check the GNU site for this
> info.
> >
> > The way I would approach this project is first by answering a few
> questions:
> > - Check out toolchain support for the processor (at the very least you
> > will need  gcc/gas). Has anyone built a toolchain (i.e. with precompiled
> > libraries) you can download and use, or will you have to build your own?
> > - How close to existing, supported processors is the new one? What are
> > the differences? Can you leverage existing code, binaries, or online
> > docs in your project?
> > - What type of memory protection (if any) does the processor support? Is
> > this different in any appreciable way from the existing supported
> > processors. This will affect the complexity in porting the uCLinux
> stuff.
> > - Do you require any major changes to the remaining  assembler-based
> > modules in uClinux (in the RT variants of Linux I have worked with this
> > is mainly located in the boot and context switch code, so at least your
> > problems should be confined to a relatively limited module set). If not,
> > your port should be very straightforward.
> > - Determine the boot and storage facilities (FLASH, disk, etc) on your
> > development kit and find out if you have to write any specific drivers
> > to support them.
> > - Determine the mechanism for loading and running a binary on your dev
> > kit. How difficult is it? Will you need special hardware or software
> > available only under Windows? How you will load and run the very first
> > binary you compile?
> > - Determine what the feasability for a debug (user AND kernel mode)
> > connection to the dev kit is (i.e. RS-232, JTAG, etc).
> >
> > If you investigate the above, I think you will get an idea as to the
> > scope of project you are considering.
> >
> > > I know it has been done with other versions of Coldfire processor
> eval. boards but this board is quite a bit different.  I just don't want
> to waste time on something that can't be done or would take forever to get
> right.
> > >
> > >
> > I have no doubt that it can be done, but the "get right" part is up to
> > the engineer involved ;-)
> >
> > Good luck. If you have any other questions, you can email me directly if
> > you like.
> >
> >   -darin
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