Interested in contributing to Beaglebone BSP
Christian Mauderer
oss at c-mauderer.de
Sun May 3 14:42:31 UTC 2020
Hello James and Vijay,
On 03/05/2020 14:33, Vijay Kumar Banerjee wrote:
> Hi James
>
> On Sun, May 3, 2020 at 4:30 PM James Fitzsimons
> <james.fitzsimons at gmail.com <mailto:james.fitzsimons at gmail.com>> wrote:
>
> Hi Christian,
>
> I tried to make a start this evening but I hate to say I ran into
> trouble getting my rtems environment setup, and after attempting to
> debug this for a couple of hours I thought I might see if you (or
> anyone else on the list) had some ideas.
>
> I started by forking
> your https://gitlab.com/c-mauderer/rtems-bbb gitlab repo and running
> make setup.
Note that the repo works only most of the time. It's more of a test repo
for me that just collects the necessary commands and repositories so I
don't have to type everything manually.
The dtc that I build there currently doesn't work. I removed the step
from the makefile so that the host dtc is used again.
>
> Everything progresses fine up until the "dtb" step in the makefile.
> At that point I get the following error:
>
> make -C /home/james/Documents/rtems/rtems-bbb//devicetree
> MACHINE=arm install
> make[1]: Entering directory
> '/home/james/Documents/rtems/rtems-bbb/devicetree'
> /home/james/Documents/rtems/rtems-bbb//install/rtems/5/bin/dtc -@ -o
> /home/james/Documents/rtems/rtems-bbb//install/rtems/5/fdt/am335x-i2c-overlay.dtbo
> /home/james/Documents/rtems/rtems-bbb/devicetree//am335x-i2c-overlay.dtso
> /home/james/Documents/rtems/rtems-bbb//install/rtems/5/bin/dtc:
> invalid option -- '@'
> Usage: dtc [options] <input file>
>
> A bit of googling turned up some information that the -@ option is
> deprecated, and sure enough running ./install/rtems/5/bin/dtc --help
> shows that the version of dtc built (Version: DTC 1.4.1-gf2f0fdf1)
> does not have the @ option. I tried modifying the makefile in the
> devicetree directory so the last two lines look like this:
>
> The -@ option is required to generate the symbols without which there
> will be errors in applying the overlay. The -@ option is not present in
> version 1.4.1, you can build 1.4.6 from the source. I recently added the
> rsb recipe for 1.4.6 but there's no bset present and the devel/dtc
> builds the 1.4.1 .
That's correct. The -@ or --symbols is only there in newer dtc versions.
Out of interest: Where did you find that the option is deprecated? It is
still there in 1.6.0.
>
> Christian: Can we make a bset for dtc-1.4.6 which can be separately
> build like build/dtc-1.4.6.bset ?
I don't think that would be a good idea before the release. After the
release we should work on a 1.6 build set. The 1.6 only needs libyaml
(or libjson?) which is no default package on FreeBSD. So we need a
solution for that on FreeBSD hosts.
>
> $(TARGETDIR)/%.dtbo: $(MAKEFILE_DIR)/%.dtso
>
> $(PREFIX)/bin/dtc -o $@ $<
>
>
> Now running $make dtb gives the following output:
>
> make[1]: Entering directory
> '/home/james/Documents/rtems/rtems-bbb/devicetree'
> /home/james/Documents/rtems/rtems-bbb//install/rtems/5/bin/dtc -o
> /home/james/Documents/rtems/rtems-bbb//install/rtems/5/fdt/am335x-i2c-overlay.dtbo
> /home/james/Documents/rtems/rtems-bbb/devicetree//am335x-i2c-overlay.dtso
> Error:
> /home/james/Documents/rtems/rtems-bbb/devicetree//am335x-i2c-overlay.dtso:2.2-8
> syntax error
> FATAL ERROR: Unable to parse input tree
> Makefile:24: recipe for target
> '/home/james/Documents/rtems/rtems-bbb//install/rtems/5/fdt/am335x-i2c-overlay.dtbo'
> failed
> make[1]: ***
> [/home/james/Documents/rtems/rtems-bbb//install/rtems/5/fdt/am335x-i2c-overlay.dtbo]
> Error 1
> make[1]: Leaving directory
> '/home/james/Documents/rtems/rtems-bbb/devicetree'
> Makefile:96: recipe for target 'dtb' failed
> make: *** [dtb] Error 2
> james at opportunity:~/Documents/rtems/rtems-bbb$
>
> I'm not quite sure where to go from here though.
>
> If I then run the following steps in the makefile manually,
> bootstrap and bsp complete, but libbsd fails with the following error:
>
> [1497/2193] Compiling freebsd/sys/netpfil/pf/pf_lb.c
> ../../freebsd/sys/arm/freescale/imx/imx6_ccm.c:54:10: fatal error:
> arm/freescale/imx/imx_ccmvar.h: No such file or directory
> #include <arm/freescale/imx/imx_ccmvar.h>
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> compilation terminated.
>
>
> This bug was recently fixed in the rtems-libbsd ( for both master and
> 5-freebsd-12 branches), if you update to recent HEAD of the libbsd, then
> this error will hopefully not be there.
>
> Best regards,
> Vijay
>
>
> Thanks for any advice you can provide.
>
> Regards,
> James Fitzsimons
>
>
>
>
>
>
> On Mon, 27 Apr 2020 at 00:25, Christian Mauderer <oss at c-mauderer.de
> <mailto:oss at c-mauderer.de>> wrote:
>
> Hello James,
>
> On 26/04/2020 12:05, James Fitzsimons wrote:
> > Hi Christian,
> >
> > Thanks for your reply.
> >
> > On Wed, 22 Apr 2020 at 23:29, Christian Mauderer
> > <christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>
> > <mailto:christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>>> wrote:
> >
> > Hello James,
> >
> > On 20/04/2020 13:13, James Fitzsimons wrote:
> > > I am interested in adding support for the eQEP (Enhanced
> Quadrature
> > > Encoder Pulse Module) which I am using to decode the
> quadrature
> > encoders
> > > on my motors.
> >
> > That one isn't implemented yet and I don't know of any
> current work on
> > it. So feel free to go ahead.
> >
> >
> > Thanks for the encouragement - I will start with the eQEP
> drivers.
> >
> >
> > > I will eventually also need support for the ADC, PRU (I
> see some work
> > > has already been done on that by a GSoC project),
> >
> > There has been some work on PRU. I'm not entirely sure
> about ADC.
> >
> > > and ideally the TI
> > > WiLink 8 WL1835MOD wireless chipset - although I realise
> that might be
> > > extremely difficult.
> >
> > That depends: What kind of interface is used for that? And
> is the chip
> > already supported in FreeBSD?
> >
> >
> > I have done a bit of research and can't find any FreeBSD
> support for it.
> > There are obviously linux drivers but I realise these are not
> suitable
> > for porting to RTEMS
>
> I had a look at the Linux drivers. They are GPL only. So you are
> right:
> They wouldn't be accepted in RTEMS. In theory you could use a
> private
> repo for a port of the drivers but expect a lot of maintenance
> effort if
> you want to keep them up to date.
>
> You should think about asking on a FreeBSD mailing list whether
> someone
> is working on a driver. Maybe someone is working on it and there
> already
> exists a partial or complete driver in some private or separate
> repository.
>
> >
> >
> > If it is an USB interface and it is supported in FreeBSD
> adding it
> > shouldn't be much work. If it is an SDIO it will get a bit
> more
> > difficult but still possible in a decent time frame. If
> FreeBSD doesn't
> > know anything about it you will have a really hard time.
> WLAN drivers
> > are _very_ complex and the need a lot of detail knowledge
> about the
> > chipset and the regulations.
> >
> >
> > I'm pretty sure it uses an SDIO interface, but as you say
> without the
> > FreeBSD support it may be a bit of a long shot.
> >
>
> Yes, seems to be SDIO. We had a GSoC project regarding SDIO two
> or three
> years ago. The student managed to do most of the work for a SDIO
> support
> in libbsd. But we could only partially merge it because at that
> point
> the libbsd was too far behind FreeBSD. One extra difficulty has been
> that SDIO was a compile time option in FreeBSD back then. You
> might want
> to take a look at the project and whether you can re-use some
> parts of
> it if you want to add the SDIO stuff.
>
> >
> > > Are drivers for these features something that would be
> welcome in the
> > > BBB BSP, and if so any tips for getting started?
> >
> > Of course. Peripheral drivers are nearly always welcome.
> >
> > For the PRU you might should contact the GSoC student
> working on the
> > topic. For WLAN: Please check the interface and FreeBSD
> support. I don't
> > know exactly what the eQEP does. But if there is a FreeBSD
> driver for it
> > you might want to check that one too and maybe port it via
> libbsd
> > (except the eQEP is a really simple module and it's a lot
> simpler to
> > write the driver yourself in the BSP)
> >
> >
> > I'll make a start on the eQEP module (quadrature decoder for
> reading
> > encoders) and if that goes well I'll reach out to Nils
> Hölscher about
> > the PRU work.
>
> Sounds good. Feel free to ask questions on the mailing list
> anytime you
> think necessary. And although I don't think that you have too much
> overlap please keep an eye on this years GSoC projects and
> whether there
> is any influence on your code or vice versa.
>
> Best regards
>
> Christian Mauderer
>
> >
> > Thanks and regards,
> > James Fitzsimons
> >
> >
> >
> > _______________________________________________
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> > users at rtems.org <mailto:users at rtems.org>
> > http://lists.rtems.org/mailman/listinfo/users
> >
>
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