Beaglebone help needed

Wed Mar 6 20:17:46 UTC 2019

Thank you for the responses!

Chris,

I was using Ben's repository and not git.rtems.org. I will test it with
https://git.rtems.org/rtems-source-builder/ some time later today to see if
it works.

Christian,

I didn't know the documentation is outdated.

I would like to understand what part of Beaglebone black BSP has not been
implemented. The list on the ticket mentioned

PRU - programmable realtime units, interesting realtime applications
I2C
ADC
Framebuffer
USB
Ethernet
GPIO
CAN
MMC (internal flash & sdcard)

>From the repository https://git.rtems.org/rtems/tree/bsps/arm/beagle, it
seems the i2c, spi, uart, gpio, pwm are implemented. I am not sure if I am
looking at the right place. So, it would be great if you could let me know,
where to look, to understand the BSP better.

I understand why we don't need the tools to build the application. I will
try your way with the scripts from the Gitlab repository and try to build a
sample application.

You mentioned a Wifi example, but there is an ethernet chip on board and no
Wifi chip. Is there a reason why an external Wifi chip is used and not the
ethernet chip? Also, are all networking applications for RTEMS going to use
the rtems-libbsd going forward?

Thank you for the help.

Regards,
Sarvesh

On Wed, Mar 6, 2019 at 8:52 AM Christian Mauderer <list at c-mauderer.de>
wrote:

> Am 06.03.19 um 12:11 schrieb Chris Johns:
> > On 6/3/19 6:07 pm, Sarvesh Patkar wrote:
> >> Hey everyone,
> >>
> >> I went through the quick start guide and could build the Hello World
> for the
> >> sparc/erc32 target.
> >>
> >> I would like to contribute to RTEMS in adding functionality and maybe,
> writing
> >> BSPs for some development boards that I have. I started with Beaglebone
> Black.
> >
> > Welcome and this sounds great.
>
> Note that the Beagle Bone Black is already quite well supported (except
> for the outdated documentation). Of course there is always room to
> improvement.
>
> >
> >> There are a few questions that I have as follows.
> >>
> >>  1. There is a build set called beagle.bset that is defined in Ben
> Gras's Github
> >>     repository (
> https://github.com/bengras/rtems-source-builder/tree/beagle),
> >>     that hasn't been merged into the main rtems-source-builder git
> repository.
> >>     Is there a way to know if that will happen?
> >
> > It could be if it is updated so it can be merged to master.
>
> The build set compiles some additional tools and libraries. The tools
> are useful but not necessary to create bootable images. Most likely Ben
> used the libraries for some project.
>
> Please note that I write the following without detailed tests from some
> notes / scripts. So there might could be typos or some problems with the
> order.
>
> For a BBB with an up to date U-Boot (newer than about 2017) on your
> Beagle you don't have to use these tools. The U-Boot that is provided by
> the official BBB images now looks for a uEnv.txt on your SD and executes
> that if it is available.
>
> You can build the toolchain and system the normal way like any other
> RTEMS tool chain (like you did for erc32) from master. Beneath that you
> need a mkimage from U-Boot. Any recent version should do. As soon as you
> have your executable you need the following steps:
>
> ----
> arm-rtems5-objcopy app.exe -O binary app.bin
>
> gzip -9 app.bin
>
> mkimage -A arm -O linux -T kernel -a 0x80000000 -e 0x80000000 -n RTEMS
> -d app.bin.gz rtems-app.img
> ----
>
> You can then copy the rtems-app.img to the root directory of a
> FAT-formatted SD card. Put a uEnv.txt with the following content beneath
> it (the line with boot=... and the following are one - my mail client
> just breaks it):
>
> ----
> setenv bootdelay 5
> uenvcmd=run boot
> boot=fatload mmc 0 0x80800000 rtems-app.img ; fatload mmc 0 0x88000000
> am335x-boneblack.dtb ; bootm 0x80800000 - 0x88000000
> ----
>
> The last file that you need is a device tree file
> (am335x-boneblack.dtb). The simplest way to get that is to copy it from
> a Linux or FreeBSD image for the BBB. Copy it together with the other
> files to the root of the disk.
>
> A disk that is prepared in that way should boot the RTEMS application if
> you put it in your BBB.
>
> Like I said: I mostly wrote that down from head / scripts. I should
> update the README of the Beagle BSP sometimes but I haven't managed to
> bring myself to do it yet.
>
> In the last two years, I have used some hacked together scripts to build
> a development environment that I used to test GSoC code. Basically it
> builds the same tools that Bens repo would build. It isn't integrated as
> nicely into RSB but it worked for me. The repo isn't totally up to date
> (last updated to RTEMS master on last Chrismas) but it should still
> work. If it helps you, you can find the scripts here:
>
>     https://gitlab.com/c-mauderer/rtems-bbb
>
> There is also a WiFi-Sample application in the repo that uses quite a
> lot of the hardware.
>
> Best regards
>
> Christian
>
> >
> >>  2. The instructions given in the blog link mentioned on the
> >>     ticket https://devel.rtems.org/ticket/2891 do not seem to work
> because the
> >>     link for fetching the mpc library is broken/wrong. (I corrected the
> link
> >>     locally and the sb-set-builder seems to go beyond that error) I
> think this
> >>     change was made already in all branches in the official repository
> but not
> >>     Ben's. I see another error while running sb-set-builder during
> compilation
> >>     of ubsan.c (gcc-6.3.0) as follows. Is there a patch for this that I
> can
> >>     apply to fix my local clone of the rsb ?
> >
> > Are you using the master version of the RSB from git.rtems.org?
> >
> > Chris
> >
> >>
> >> ../../gcc-6.3.0/gcc/ubsan.c: In function 'bool
> ubsan_use_new_style_p(location_t)':
> >> ../../gcc-6.3.0/gcc/ubsan.c:1474:23: error: ISO C++ forbids comparison
> between
> >> pointer and integer [-fpermissive]
> >>        || xloc.file == '\0' || xloc.file[0] == '\xff'
> >>
> >> Any help in this matter is highly appreciated. If not the Beaglebone
> black, I
> >> have some ARM Cortex-M boards that I would like to work towards.
> >>
> >> Thank you for the help.
> >>
> >> Regards,
> >> Sarvesh
> >>
> >> _______________________________________________
> >> users mailing list
> >> users at rtems.org
> >> http://lists.rtems.org/mailman/listinfo/users
> >>
> > _______________________________________________
> > users mailing list
> > users at rtems.org
> > http://lists.rtems.org/mailman/listinfo/users
> >
>
>
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