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

Sat Aug 8 19:58:41 UTC 2020

On Sat, Aug 8, 2020 at 11:10 PM Gedare Bloom <gedare at rtems.org> wrote:

> On Sat, Aug 8, 2020 at 11:08 AM Mritunjay Sharma
> <mritunjaysharma394 at gmail.com> wrote:
> >
> >
> >
> > 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).
> >
>
> Probably they should be provided by EPICS for known-to-work
> configurations. If they are not, we should push upstream.
>
> >
> > 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?
> >>
>
> I still think this should be done through some kind of pre-processing
> (scripting) over these configuration files for a given target, using
> some fixed pattern, rather than by patching. A patch is fine for
> proof-of-concept, but I don't think we want to have x patches for x
> BSP targets of EPICS.  Maybe it is fine, there aren't that many BSP
> targets right now, but I can see this kind of patch-based
> configuration getting a little unwieldy.
>
> If you proceed with the patch-based approach, you need to figure out
> how to pick the right patch to apply based on the target/bsp build. So
> that would be your next step. Create a patch for the zynq, and see if
> you can dynamically determine which one to apply (zynq or pc386) based
> on RSB internal state/variables.
>
> Thank you for the suggestions. I will start working on creating the patch
for zynq and will see if
something can be done to dynamically determine them.

> >>
> >> >
> >> > 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.
>
> We just need to be ready for when RTEMS 5.1 is officially released.
> Hopefully soon, but I don't have a timeline. Releases are mostly
> volunteer time, so they happen when they happen. We're trying to get
> better about that, but it is hard (due to lack of incentives).
>
> I think that makes it clear, Heinz.

> >>
> >>
> >> 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?
>
> Prepare the zynq patch and try to work out the logic of how to select
> the right patch to apply.
>
> Then similar logic might be usable to script the configuration changes
> of EPICS so we don't need patches.
>
> Sure, I will do and update soon.

> > And yes how to begin the testing part?
>
> This was suggested by Heinz earlier to look at the CI test scripts
> that EPICS maintainers use.
>

Yes, it slipped out of my mind. Will check and revert.

Thanks
Mritunjay Sharma

>
> > 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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