Info regarding development activity in RTEMS for ARM bsps/Raspberry pi

Alan Cudmore alan.cudmore at gmail.com
Wed Aug 20 13:37:18 UTC 2014


Hi Ritesh,
For the Raspberry Pi, Andre Marques added GPIO, SPI, and I2C support for
his Google Summer of Code project. When this code is merged, it will allow
many other devices to work on the Pi. There is still plenty of other work
to do on the Raspberry Pi BSP including:
- JTAG debugging - I have not had the time to continue my work with the
MiniMod/OpenOCD JTAG debugger. It currently does not work reliably for me.
Another user is using a second Raspberry Pi as a JTAG interface.
- SD card driver - Some work has been done by Andre towards this.
- USB/Network - The ethernet device goes through the USB interface, which
means that a USB stack has to be in place to access the ethernet chip.
- Console & Framebuffer graphics
- Sound?

As you can see, there is plenty to work on with the Raspberry Pi BSP. There
are also plenty of other boards/BSPs to work on, but I am biased. There are
over 2.5 million Pi's out there, and I believe that having first class
RTEMS support will help to expand the RTEMS user base.

Links to Andre's GSOC work:
http://www.rtems.org/wiki/index.php/Raspberry_Pi_BSP_Peripherals

and the blog
http://asuolgsoc2014.wordpress.com/2014/08/18/testing-the-project/

Alan


On Wed, Aug 20, 2014 at 5:40 AM, Hesham Moustafa <heshamelmatary at gmail.com>
wrote:

> Hi Ritesh,
>
> On Wed, Aug 20, 2014 at 11:28 AM, Ritesh Harjani
> <ritesh.harjani at gmail.com> wrote:
> > Hi All,
> >
> > I have been following RTEMS from quite some time rather I would say my
> > questions have been on & off from this community (although I haven't
> > contributed anything yet). So, this mail is mainly regarding some help
> from
> > the community members so that I can pitch in to contribute something to
> this
> > community.
> >
> > Based on my knowledge I would like to start from ARM bsps/raspberry pi
> as I
> > am seeing quite lot of development activity going on in these areas.
> >
> > If someone can guide me with the following activities it would be great:
> >
> > 1. I need to just start something, may be with a small patch (which
> should
> > be related to the above mentioned area):
> > Earlier I thought of starting with some driver development but without
> > having basic knowledge of RTEMS file structure/other areas, I wasn't
> able to
> > complete it.
> >
> > 2. Need to understand the boot flow and the code initialization routine
> > which can give me an idea as to where all and what all drivers are
> present
> > etc etc..
> >
> >
> > Later may be I can think of porting/developing some driver for any ARM
> bsp.
> >
> >
> > Background activity done till now:
> >
> > 1. Followed all the steps in Alan's Blog
> > (
> http://alanstechnotes.blogspot.in/2013/03/running-your-first-rtems-program-on.html
> ):
> > I was able to run ticker.exe sample test on Raspberry pi. Although there
> are
> > some doubts which I have asked below.
> >
> > 2. Ordered OpenOCD based JTAG board. Once this comes I will make this
> JTAG
> > board start working.
> >
> >
> > Queries:
> > 1. Is by default raspberry pi MMU enabled and all the page table are
> setup
> > ?(from HEAD of git://git.rtems.org/rtems.git)
> >
> > 2. I cannot see any libmmu tests which I think Hesham developed during
> GSOC
> > 2013 ?
> > Do we keep this into different git ?
> >
> Some of my project code has been merged (mainly low-level parts of
> libmm implemented for Raspberry Pi). The other code is held in my old
> github repo here https://github.com/heshamelmatary/rtems-gsoc2013
> > 3. With OpenOCD and gdb is it possible to see all the CP15 coprocessor
> > registers on ARM ?
> >
> > 4. How was Hesham able to debug and see the MMU register settings(like
> > SCTLR.MMU) during his work on GSoc 2013 libmmu development for raspberry
> pi
> > ? Was it QEMU ?
> >
> I was using QEMU for debugging Xilinx Zynq BSP, as well as Realview.
> For Raspberry Pi (worked on the HW board, no simulators), I just used
> printf to print out the values of registers which I need to peek into.
> >
> >
> > Please feel free to guide me through the work plan if anyone have in
> his/her
> > mind for ARM bsps.
> >
> >
> >
> > Thanks
> > Ritesh Harjani
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
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>
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