[GSoC 2020] : BSP Buildset for EPICS (next steps)

Sat Aug 8 17:08:26 UTC 2020

On Sat, Aug 8, 2020 at 9:46 PM Heinz Junkes <junkes at fhi-berlin.mpg.de>
wrote:

> Hallo Mritunjay,
> everything looks pretty good. I'm commenting on the text. I also send this
> mail
> to two EPICS experts (Andrew Johnson and Michael Davidsaver). Maybe they
> also have some ideas.
>

Thank you so much Heinz! It will be really a great help!

>
>
> >
> > Current Status:
> >
> > 1) Successfully built EPICS7 with RTEMS5 by hand for pc-386
> > 2) Worked for RSB recipe.
> >    In its due process, I Wrote:
> >     i) rsb/rtems/config/epics/epics-7-1.cfg
> >     ii)rsb/rtems/config/epics/epics-base.bset
> >     iii)rsb/source-builder/config/epics-7-1.cfg
> > 3) Added Patch for RTEMS-pc-386 support which made the above recipe work
> successfully.
> > 4) Therefore, Successully built EPICS7 with RTEMS5 by using RSB recipe
> as well for pc-386 as of now.
> > 5) Sent 4 Patches for review of the same.
> >
> > What problems are in the next steps?
> >
> > 1) How to make it work across different architectures?
> > 2) Exisiting EPICS works on the old legacy network stack.
> > 3) I am not using EPICS upstream branch. It is being built
> > by Heinz's epics playground.
> > 4) Doubts in how to start with testing.
> >
> > My Resarch work for the Problem no: 1
> >
> > I have gone through the EPICS developer guide from here
> > exhaustively in the past couple of day and here are few interesting
> things
> > that I found which can help:
> >
> > 1) "The main ingredients of the build system are:
> > • A set of configuration files and tools provided in the EPICS
> base/configure directory
> > • A corresponding set of configuration files in the <top>/configure
> directory of a non-base <top> directory
> > structure to be built. The makeBaseApp.pl and makeBaseExt.pl scripts
> create these configuration files. Many of
> > these files just include a file of the same name from the base/configure
> directory.
> > • Makefiles in each directory of the <top> directory structure to be
> built
> > • User created configuration files in build created
> $(INSTALL_LOCATION)/cfg directories.
> > "
> >
> > Remarks: Now since it is also mentioned in the guide that
> "makeBaseApp.pl
> > creates directories and then copies template files into the newly
> created directories
> > while expanding macros in the template files. EPICS base provides two
> sets of template files: simple and example."
> > Can we think of using makeBaseApp.pl to that end? Making the user allow
> > to change the configurations from the terminal?
>
> I don't think that makeBaseApp.pl will help you. This is intended to build
> an example IOC. It takes the settings from the above mentioned
> configuration files.
>
> You "only" need to specify the location of the RTEMS installation in
> configure/os/CONFIG_SITE.Common.RTEMS.
> RTEMS_VERSION =
> RTEMS_BASE =
>
> Then you have to define the target in configure/CONFIG_SITE:
> ...
> # Which target architectures to cross-compile for.
> #  Definitions in configure/os/CONFIG_SITE.<host>.Common
> #  may override this setting.
> CROSS_COMPILER_TARGET_ARCHS=
> …
> e.g. “CROSS_COMPILER_TARGET_ARCHS=RTEMS-xilinx_zynq_a9_qemu"
>
> And for each target there must be a file in configure/os:
> e.g. CONFIG_Common.RTEMS-xilinx_zynq_a9_qemu
> If it is not provided by EPICS, the RSB should install it there (adapted
> to the target to be used by epics make).
>

Yes, Heinz. I followed the above steps and created a patch which I applied
in the configuration files of RSB recipe.
The problem with it is that it's made only for pc-386 and I have to
hardcode there about location of the RTEMS installation in
configure/os/CONFIG_SITE.Common.RTEMS. My doubt is how to modify the patch
that can it offer user-specific location of the RTEMS
installation and bsp?

>
> >
> > 2) "The startup directory in EPICS base contains a perl script,
> EpicsHostArch.pl, which can be used to define
> > EPICS_HOST_ARCH. This script can be invoked with a command line
> parameter defining the alternate compiler (e.g.
> > if invoking EpicsHostArch.pl yields solaris-sparc, then invoking
> EpicsHostArch.pl gnu will yield
> > solaris-sparc-gnu).
> > The startup directory also contains scripts to help users set the path
> and other environment variables”
> This has nothing to do with 2)
>

I am sorry for the misunderstanding. All the 4 points mentioned here are my
observations only for the Problem No.1
`1) How to make it work across different architectures?`

>
> There's no need to adjust anything here. The EPICS make recognizes the
> architecture on which it is started.
>
> > Remarks: As EPICS_HOST_ARCH, can we do something similar for
> CROSS_COMPILER_TARGET_ARCHS?
> >
> > 3) ") The following is a summary of targets that can be specified for
> gnumake:
> > • <action>
> > • <arch>
> > • <action>.<arch>
> > • <dir>
> > • <dir>.<action>
> > • <dir>.<arch>
> > • <dir>.<action>.<arch>
> > where:
> > <arch> is an architecture such as solaris-sparc, vxWorks-68040,
> win32-x86, etc.
> > <action> is help, clean, realclean, distclean, inc, install, build,
> rebuild, buildInstall, realuninstall, or uninstall"
> >
> > Remarks: Now similar to the above stated, can we work for Cross Compiler
> target Architecture?
> >
>
> But this does not refer to 3) ?

No no, this remark is also for the problem 1 only as told above. Slight
misunderstanding here :)

>

> 3) You have to take "my" repo at the moment, because the adaptations to
> RTEMS5 are not yet included in the official epics-base. This is a
> hen-and-egg problem because RTEMS is only now in the release phase, so my
> changes have not been implemented yet.
>

Ok, I hope Dr. Gedare and Chris can help you with that.

>
> 2) I'm just about to figure out in the Epics Makefiles whether the target
> was built with the legacy-stack or libbsd-stack. It's working already.
> Now I also have to adjust the rtems_init.c accordingly. Here I have to
> clean up a little bit. But I hope to have this finished by the middle of
> the week.
>

Thank you so much for the update!

So I would like to ask my other mentors - what can I do for the time being?
What should be the next steps for this week?
And yes how to begin the testing part?
I have tried to find some resources but I think it will be
better if you can help somewhere to look at.

Thanks
Mritunjay Sharma

>
> > These were the little doubts that originated from the research work I
> did.
> > I will like the opinion of mentors that what can be the optimal way now
> to approach the
> > project after this? What can be some resources for better research work
> of the
> > above problems?
> >
> > Also, for the reference:
> > Link to the changes in commits of rsb can be found here:
> https://github.com/RTEMS/rtems-source-builder/compare/master...mritunjaysharma394:epics-support
> >
> > The patch for epics can be found here:
> https://github.com/mritunjaysharma394/epics-mritunjay/tree/master/patches
> >
> >
> > Thanks
> > Mritunjay Sharma
> >
> >
> >
> >
> Heinz
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