GSoC'18-Introduction

Russell Haley russ.haley at gmail.com
Sun Feb 25 17:45:20 UTC 2018 

Sorry for the top post. 

Dts file in freebsd tree are here. The Dts files are imported from Linux for compatability. 

https://svnweb.freebsd.org/base/head/sys/gnu/dts/arm/

Russ

Sent from my BlackBerry 10 smartphone on the Virgin Mobile network.
  Original Message  
From: Christian Mauderer
Sent: Sunday, February 25, 2018 2:32 AM
To: Udit agarwal; Users
Subject: Re: GSoC'18-Introduction

Am 25.02.2018 um 08:41 schrieb Udit agarwal:
> Hi,
> I did build libbsd for beagleboneBlack and executed selectpollkqueue01
> test successfully.(Logs:here
> <https://gist.github.com/madaari/ae7b3334514a9aec3b063eaa3a0dcd05>)
> However, while trying to access SD card, media01 test failed with an
> error "fatal source: 9 (RTEMS_FATAL_SOURCE_EXCEPTION)  " (Logs:here
> <https://gist.github.com/madaari/c6d524bc06e896359f9535d90c0a447a>)
> I tried debugging the script, by putting printf statements in various
> functions, but it seems like it's failing even before entering test_main().
> Also, is there a better method with which we can debug RTEMS scripts?
> 
> Thanks,
> Udit Agarwal

Hello Udit,

it's great that you can already compile and run some of the libbsd examples.


Regarding your problem with the SD card: Note that the BBB BSP uses the
flattened device tree (at least the libbsd on BBB does). Therefore you
have to load a dtb too. My U-Boot boot lines looks like follows:

fatload mmc 0 0x80800000 rtems-app.img
fatload mmc 0 0x88000000 am335x-boneblack.dtb
bootm 0x80800000 - 0x88000000

I create a SD-Card image with a script that is based on one that is (or
was) contained some time back in the BSP. You can have a look here:

https://gitlab.com/c-mauderer/rtems-bbb/blob/master/build/create-sdcardimage.sh

The script does a lot of things that are not necessary any more (like
copying a U-Boot to the SD card). Basically the necessary points would
be to create a image and an uEnv.txt (with the lines from 78 to 83). You
can use the dtb file that is provided by a FreeBSD or a Linux for BBB.


Regarding debugging the application: I would strongly recommend to use
some kind of hardware JTAG debugger. Some Beagle Bone variants have an
on-board debugger (I think mainly the older white one). For others you
can use hardware debuggers like quite a number of adapters supported by
OpenOCD (FlySwatter2, simple FTDI-based ones, ...), Segger J-Link (in
your case the EDU version) or whatever you find that can debug the BBB.

It may be possible to use the libdebugger as a serial debugger. But I
never used it so I'm not sure how well you can debug through the libbsd
with it. I'm also not sure whether it works for the BBB. Chris Johns
added the ARM support some time back. Maybe he can give you any hints if
you want to try libdebugger.

Best Regards

Christian Mauderer

> 
> On Fri, Feb 23, 2018 at 11:25 PM, Christian Mauderer <list at c-mauderer.de
> <mailto:list at c-mauderer.de>> wrote:
> 
> Am 23.02.2018 um 05:17 schrieb Udit agarwal:
> > Hi,
> > Thanks for your help mentors,
> > Since last time, I have managed to modify and execute hello world
> > application on both the platforms, my local machine(Ubuntu 14.04) and
> > BeagleBone Black.
> > I have attached the screenshots and patch file as proof and  detailed
> > logs can be found on these(1
> > <https://gist.github.com/madaari/8aae37012d0d175b859c6471a5b13248
> <https://gist.github.com/madaari/8aae37012d0d175b859c6471a5b13248>>
> and 2
> > <https://gist.github.com/madaari/a7f1d223fb0513e4890025fd1ba6184d
> <https://gist.github.com/madaari/a7f1d223fb0513e4890025fd1ba6184d>>)
> gists.
> > Moreover, I went through all the mentioned projects, and found a few of
> > them(Like extending support for PRU, integration of networking stack
> > ,porting RTEMS on PocketBeagle etc) really interesting and doable
> > withing the given time constraint!
> > So, i thought of starting off by studying a bit about the networking
> > stack, its implementation etc. Please recommend few resources from where
> > i can explore this.
> >
> > Regards,
> > Udit agarwal
> >
> 
> Hello Udit,
> 
> it's great that you already have build and successfully executed the
> example on BBB.
> 
> Regarding the network stack. First of all: Note that there are at least
> three network stacks in RTEMS:
> 
> 1. The "old" one which is integrated into the RTEMS sources. This one
> exists since quite some time in RTEMS. It is a fork of a really old
> version of the FreeBSD network stack and it has been heavily adapted
> during the time. I think there is a manual regarding this stack on the
> docs.rtems.org <http://docs.rtems.org>. It has only IPv4 support.
> 
> 2. The "new" one which lives in it's own libbsd repository. That one is
> a fork of the latest FreeBSD development version. One of the important
> points during the development has been that the sources should be as
> close as possible to the upstream FreeBSD sources. This makes it simpler
> to keep up to the FreeBSD development. This one can IPv4 and IPv6 and
> should be basically able to support everything FreeBSD does. Beneath
> that it also brings in USB and SD-Card support and some other subsystems
> of FreeBSD.
> 
> 3. I'm quite sure that I have seen some posts about the lwIP
> (lightweight IP) stack used together with RTEMS.
> 
> 
> Most network stack related projects on the open projects page refer to
> the libbsd (second one in my list). So you most likely should
> concentrate on that one.
> 
> The big disadvantage of the libbsd is that it heavily lacks
> documentation. The main documentation is the one big libbsd.txt in the
> source tree (https://git.rtems.org/rtems-libbsd/tree/libbsd.txt
> <https://git.rtems.org/rtems-libbsd/tree/libbsd.txt>) and
> some other files (like CONTRIBUGING.md).
> 
> If you want to work on the libbsd, I would suggest that you try to build
> it for the Beagle Bone Black and for example access the SD card content.
> 
> For that I would suggest to take a look at the libbsd.txt and maybe at
> the work of last years students (for the libbsd in 2017 that is mainly
> Sichen Zhao). Please ask any question you have on the mailing list. And
> please write down everything you learn and add it to the libbsd.txt. It
> would be a really great start to improve that document.
> 
> Best regards
> 
> Christian Mauderer
> 
> > On Thu, Feb 22, 2018 at 12:28 AM, Christian Mauderer <list at c-mauderer.de <mailto:list at c-mauderer.de>
> > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>> wrote:
> >
> >
> >
> >     Am 21.02.2018 um 00:14 schrieb Joel Sherrill:
> >     >
> >     >
> >     > On Tue, Feb 20, 2018 at 3:23 PM, Gedare Bloom <gedare at rtems.org <mailto:gedare at rtems.org> <mailto:gedare at rtems.org
> <mailto:gedare at rtems.org>>
> >     > <mailto:gedare at rtems.org <mailto:gedare at rtems.org>
> <mailto:gedare at rtems.org <mailto:gedare at rtems.org>>>> wrote:
> >     >
> >     >     Hello and welcome,
> >     >
> >     >     For projects that intend to use a specific board, we
> require that you
> >     >     can demonstrate some proficiency with the board itself.
> In this case,
> >     >     you should be able to run RTEMS on the BBB first. Now,
> there has been
> >     >     significant progress made on BBB support, so hopefully
> someone may
> >     >     chime in with what else might remain to be done with it.
> With a little
> >     >     bit of digging, you should be able to find prior
> students and mentors
> >     >     for BBB related projects.
> >     >
> >     >
> >     > My recollection is that the student working on Wifi got it
> working
> >     with a
> >     > USB dongle on either the BBB or Pi. The Wifi stack still
> needs work
> >     > independent of any BSP and we have listed that as a project.
> >     >
> >     > But I thought the BBB was in pretty good shape overall. But
> that's
> >     just
> >     > from memory.
> >     >
> >     > --joel
> >     >  
> >
> >     Hello,
> >
> >     I have been a mentor for Sichen last year. He has done some driver
> >     support for the core RTEMS BSP of the BBB last year and he
> ported the
> >     necessary libbsd drivers to use a USB WiFi dongle on that
> board. He also
> >     put a lot of work into the encrypted WiFi support.
> >
> >     I think the year before Punit has worked on the BBB BSP.
> >
> >     Like Joel already said, the core BBB is quite well supported.
> But there
> >     are still some drivers like CAN, Ethernet or USB OTG (to name
> a few)
> >     that could be implemented. I've posted an update to the ticket
> on BBB
> >     (#2891) some weeks back.
> >
> >     There are also still two projects regarding the WiFi support
> that could
> >     be done. The BBB is a really good platform for that. That
> would be the
> >     tickets #3222 and #3223.
> >
> >     You can find the tickets linked on the open projects page in
> the wiki.
> >
> >     Regards
> >
> >     Christian
> >
> >     >
> >     >
> >     >     Gedare
> >     >
> >     >     On Tue, Feb 20, 2018 at 1:56 PM, Udit agarwal
> <dev.madaari at gmail.com <mailto:dev.madaari at gmail.com>
> <mailto:dev.madaari at gmail.com <mailto:dev.madaari at gmail.com>>
> >     >     <mailto:dev.madaari at gmail.com <mailto:dev.madaari at gmail.com>
> <mailto:dev.madaari at gmail.com <mailto:dev.madaari at gmail.com>>>> wrote:
> >     >     > Hi,
> >     >     > I am Udit Agarwal(irc handle: madaari), pursuing my undergraduate
> >     >     degree in
> >     >     > Electronics Engineering from Netaji subash Institute of
> >     >     Technology, India.
> >     >     > I had some experience of TI-RTOS on MSP432(Cortex M)
> >     >     microcontroller, with a
> >     >     > pretty good grasp on Beagle Bone Black and other hardware stuff.
> >     >     I'm pretty
> >     >     > excited about the project of improving RTEMS support on Beagle
> >     >     Bone Black,
> >     >     > and would thus like to compete for it.
> >     >     > Being already started with RTEMS documentation and the Hello World
> >     >     project,
> >     >     > I would like to know about any other resources i can consider
> >     >     apart from
> >     >     > documentation and RSB guide, for this specific BSP(Beagle Bone Black)?
> >     >     >
> >     >     > Thanks,
> >     >     > Udit Agarwal
> >     >     >
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