[Rxtx] Kaffe & rxtx & armv5b

[Maxwell Zempftman]

>On Wed, 1 Dec 2004, Jari Korva wrote:

> On Wed, 24 Nov 2004, Dalibor Topic wrote:
> > >
> > > Thanks, this helped! Kaffe and rxtx seem to work for me without any
> > > problems now.
> > >
> > > - Jari
> > >
> > > PS. Using an older armv5b gcc version, the compile failed because of
> > > undefined SSIZE_MAX in RS485Imp.c, I2CImp.c and RawImp.c. Luckily, this
> > > was easy to fix based on an example I found from SerialImp.h.
> >
> > Wow, that's fantastic! A lot of people have been asking for that.
> >
> > Could you please, please write a FAQ.rxtx for Kaffe's documentation on how to
> > go about it? I'd love to merge rxtx into kaffe eventually, as it would be a
> > wonderful tool to have on embedded systems.
> 
> OK, here's a short description of what I did:
> 
> ----
> 
> You need a version of RXTX which is *newer* than 2.1-7pre17.
> Currently (2004-12-01) such a version has not been released but you have
> to get it from cvs:
> 
> # export \
> CVSROOT=:pserver:anonymous at cvs.milestonesolutions.com:/usr/local/cvsroot
> # cvs login
> (password is mousy)
> # cvs checkout -r commapi-0-0-1 rxtx-devel
> # cd rxtx-devel
> 
> Then build the sources:
> 
> # ./configure
> # make
> 
> Ïf you are cross compiling, remember to specify the compiler and the
> architecture (these commands are for big endian ARM/XScale, i.e. armv5b):
> 
> # export CC=armv5b-softfloat-linux-gcc
> # ./configure --host=i686-linux --target=armv5b-softfloat-linux
> # make
> 
> If the compiler complains about undeclared SSIZE_MAX, add the following
> lines to those C-files which failed to compile:
> 
> #ifndef SSIZE_MAX
> #           define SSIZE_MAX  INT_MAX
> #endif
> 
> After a successful compile, install the files into your Kaffe directory
> (again, these commands are for armv5b architecture, remember to adjust the
> directories for your architecture):
> 
> # mv armv5b-softfloat-linux-gnu/.libs/*.so /usr/local/jre/lib/arm
> # cp RXTXcomm.jar /usr/local/jre/lib
> 
> Finally, add RXTXcomm.jar to your classpath
> 
> # export CLASSPATH=${CLASSPATH}:/usr/local/jre/lib/RXTXcomm.jar
> 
> Now you should be able to access your serial ports from Kaffe! Note that
> RXTX 2.1 uses gnu.io package name instead of javax.comm.
> 
> ----
> 
> I'm not sure if the instructions are optimal (e.g. does Kaffe have a
> similar ext directory for jars as SUN JRE so that I wouldn't need to
> define CLASSPATH?), but they did the trick for me :)
> 
------------------------------------------------------------------------------------------------------

>Yep.  The CVS material should fix many JRE segfaults people ran into with
>kaffe, on bsd, ....  I just finished teaching classes here and have a
>couple things to add for further baud rate control then we will release it
>at rxtx.org.

>The code from there should make it over to the classplathx project which 
>has their own upper level classes in javax.comm and no license agreements 
>with Sun.  Kaffe had some upper level classes too at one time the source 
>could work in.

>Anyhow people will be able to use that code in javax.comm name spaces.  
>Just not from rxtx.org unless they obtain the wrapper classes from Sun, 
>kaffe, or classpathx.  Classpathx makes the most sense to me as it is an 
>extension API.

Hey, I'm new to the mailing list so I don't know if I'm posting this
the right way.

Basically, I'm trying to run Kaffe and rxtx on a small device (128mb
ram, 32mb flash drive) running embedded linux on Intel XScale IXP 422.

So far I have successfully cross-compiled Kaffe (CVS-2004-11) to run
HelloWorld. The main application I want to run requires rxtx, so I
followed the guide above, and cross-compiled rxtx-devel (full
replacement version for Sun's commapi). I loaded it onto the XScale
device with Kaffe and attempted to run the application:

java -Xbootclasspath/a:/usr/kaffe/jre/lib/RXTXcomm.jar MainApp

Without any arguments, this returned the Usage message ("MainApp
USAGE: MainApp /dev/ttyxx").
As soon as I gave any arguments, such as "/dev/ttyS0", "/dev/ttyM0",
the application crashed with a NullPointerException. I looked in the
code, and I could see that the application was failing because it was
trying to print the contents of an uninitialized variable. In other
words, the code basically looked like this:

1: class serialPort serialPort;
2: class outputStream outCOMstream;
3: outCOMstream = serialPort.getOutputStream();
4: outCOMstream.write(bytes);

Step 3 does not happen. I'm not sure what the problem is exactly, but
outCOMstream remains null, so step 4 fails as well with
NullPointerException.

This isn't my code, so I don't completely understand it, but it worked
find with Sun's commapi on a RedHat Linux i686 box with Sun jdk1.4.2.
It also worked with rxtx-devel (full Sun commapi replacement) on the
Linux i686 box with Sun jdk1.4.2. Thus far, I have not gotten it to
run with any rxtx version using Kaffe on the i686. This results in a
segfault, so I believe the problem is with a miscompiled Kaffe, not an
rxtx problem.

Essentially, I need help trying to understand why the comm-enable
application is failing on the XScale device. It does not segfault, and
I do not know what is the cause of the NullPointerException. Are the
rxtx libraries not working? Is it a java code issue?

Also, does anyone know or think it is possible to run Sun's commapi on
XScale with rxtx?

Thanks,
Max.