[PATCH v4] doc/raspberrypi: Added instructions for raspberrypi

Thu Feb 13 17:30:20 UTC 2020

On Thu, Feb 13, 2020 at 10:57 PM Alan Cudmore <alan.cudmore at gmail.com>
wrote:

> I get exceptions when trying to run hello.exe.
> I'm using qemu-system-arm v 2.11.1 from ubuntu. Should I try using the
> one built by RSB?
>
No this should be fine. Can you post a screenshot of the output?

> I was trying to get this setup to try RPI 2 SMP in QEMU. I may want to
> get the latest repo and do a clean build to try this again.
>
SMP doesn't work well with QEMU. Did you try set scheduler-locking on in
GDB?
Running the executables directly in QEMU doesn't work.

> Thanks,
> Alan
>
> On Thu, Feb 13, 2020 at 12:12 PM G. S. Niteesh <gsnb.gn at gmail.com> wrote:
> >
> > On Thu, Feb 13, 2020 at 10:40 PM Alan Cudmore <alan.cudmore at gmail.com>
> wrote:
> >>
> >> Hi Niteesh,
> >> I have followed your instructions for getting RTEMS running on the Pi
> >> 1 and 2. SMP currently is not working on the 2 for me, but that is not
> >> a problem with these instructions.
> >> I started to try running on QEMU following your instructions but have
> >> not been able to get time to complete my tests.
> >
> > What problem are you exactly facing?
> >>
> >>
> >>
> >> But this is a vast improvement over "TODO", so I recommend accepting
> >> this change.
> >>
> >> Thanks for creating this,
> >> Alan
> >>
> >> On Thu, Feb 13, 2020 at 1:49 AM G. S. Niteesh <gsnb.gn at gmail.com>
> wrote:
> >> >
> >> > Can someone take a look at this, It has been unnoticed for quite a
> while.
> >> >
> >> > Thank you,
> >> > Niteesh
> >> >
> >> > On Sat, Jan 25, 2020 at 10:49 PM G S Niteesh <gsnb.gn at gmail.com>
> wrote:
> >> >>
> >> >> Added instructions to run examples on raspberrypi.
> >> >> ---
> >> >>  user/bsps/arm/raspberrypi.rst | 111
> +++++++++++++++++++++++++++++++++-
> >> >>  1 file changed, 110 insertions(+), 1 deletion(-)
> >> >>
> >> >> diff --git a/user/bsps/arm/raspberrypi.rst
> b/user/bsps/arm/raspberrypi.rst
> >> >> index 4ef75bd..72889a5 100644
> >> >> --- a/user/bsps/arm/raspberrypi.rst
> >> >> +++ b/user/bsps/arm/raspberrypi.rst
> >> >> @@ -5,4 +5,113 @@
> >> >>  raspberrypi
> >> >>  ===========
> >> >>
> >> >> -TODO.
> >> >> +This BSP supports `Raspberry Pi 1` and `Raspberry Pi 2` currently.
> >> >> +The support for `Raspberry Pi 3` is work under progress.
> >> >> +The default bootloader on the Raspberry Pi which is used to boot
> Raspbian
> >> >> +or other OS can be also used to boot RTEMS. U-boot can also be used.
> >> >> +
> >> >> +Setup SD card
> >> >> +----------------
> >> >> +
> >> >> +The Raspberry Pis have an unconventional booting mechanism. The GPU
> >> >> +boots first, initializes itself, runs the bootloader and starts the
> CPU.
> >> >> +The bootloader looks for a kernel image, by default the kernel
> images must
> >> >> +have a name of the form ``kernel*.img`` but this can be changed by
> adding
> >> >> +`kernel=<img_name>` to ``config.txt``.
> >> >> +
> >> >> +You must provide the required files for the GPU to proceed. These
> files
> >> >> +can be downloaded from
> >> >> +`the Raspberry Pi Firmware Repository <
> https://github.com/raspberrypi/firmware/tree/master/boot>`_.
> >> >> +You can remove the ``kernel*.img`` files if you want too, but don't
> touch
> >> >> +the other files.
> >> >> +
> >> >> +Copy these files in to a SD card with FAT filesystem.
> >> >> +
> >> >> +Kernel image
> >> >> +------------
> >> >> +
> >> >> +The following steps show how to run ``hello.exe`` on a Raspberry Pi
> 2.
> >> >> +The same instructions can be applied to Raspberry Pi 1 also.
> >> >> +Other executables can be processed in a similar way.
> >> >> +
> >> >> +To create the kernel image:
> >> >> +
> >> >> +.. code-block:: none
> >> >> +
> >> >> +     $ arm-rtems5-objcopy -Obinary hello.exe kernel.img
> >> >> +
> >> >> +Copy the kernel image to the SD card.
> >> >> +
> >> >> +Make sure you have these lines below, in your ``config.txt``.
> >> >> +
> >> >> +.. code-block:: none
> >> >> +
> >> >> +     enable-uart=1
> >> >> +     kernel_address=0x200000
> >> >> +     kernel=kernel.img
> >> >> +
> >> >> +Testing using QEMU
> >> >> +------------------
> >> >> +
> >> >> +QEMU can be built using RSB. Navigate to
> ``<SOURCE_BUILDER_DIR>/rtems``
> >> >> +and run this command.
> >> >> +
> >> >> +.. code-block:: none
> >> >> +
> >> >> +     $ ../source-builder/sb-set-builder --prefix=<TOOLCHAIN_DIR>
> devel/qemu4.bset
> >> >> +
> >> >> +**Note**: Replace ``<SOURCE_BUILDER_DIR>`` and ``<TOOLCHAIN_DIR>``
> with the
> >> >> +correct path of the directories. For example, if you used
> quick-start section
> >> >> +as your reference, these two will be ``$HOME/quick-start/src/rsb``
> and
> >> >> +``$HOME/quick-start/rtems/5`` respectively,
> >> >> +
> >> >> +QEMU along with GDB can be used for debugging, but it only supports
> >> >> +Raspberry Pi 2 and the emulation is also incomplete. So some of the
> >> >> +features might not work as expected.
> >> >> +
> >> >> +Make sure your version of QEMU is newer than v2.6, because older
> ones don't
> >> >> +support Raspberry Pis.
> >> >> +
> >> >> +.. code-block:: none
> >> >> +
> >> >> +     $ qemu-system-arm -M raspi2 -m 1G -kernel hello.exe -serial
> mon:stdio -nographic -S -s
> >> >> +
> >> >> +This starts QEMU and creates a socket at port ``localhost:1234``
> for GDB to
> >> >> +connect.
> >> >> +
> >> >> +The Device Tree Blob (DTB) is needed to load the device tree while
> starting up
> >> >> +the kernel. The BSP uses information from this file to initialize
> the drivers.
> >> >> +
> >> >> +Make sure you pass in the correct DTB file. There are currently two
> version of
> >> >> +DTB for the Raspberry Pi 2 ``bcm2709-rpi-2-b.dtb`` and
> ``bcm2710-rpi-2-b.dtb``.
> >> >> +The ``bcm2709-rpi-2-b.dtb`` is for Raspberry Pi 2 Model B and
> >> >> +``bcm2710-rpi-2-b.dtb`` is for Raspberry Pi 2 Model B v1.2
> >> >> +
> >> >> +We need to pass in the DTB file to GDB before running the example.
> >> >> +
> >> >> +In a new terminal, run GDB using
> >> >> +
> >> >> +.. code-block:: none
> >> >> +
> >> >> +     $ arm-rtems5-gdb hello.exe
> >> >> +
> >> >> +This will open GDB and will load the symbol table from hello.exe.
> Issue the
> >> >> +following commands in the GDB prompt.
> >> >> +
> >> >> +.. code-block:: none
> >> >> +
> >> >> +     (gdb) tar remote:1234
> >> >> +     (gdb) load
> >> >> +     (gdb) restore bcm2709-rpi-2-b.dtb binary 0x2ef00000
> >> >> +     (gdb) set $r2 = 0x2ef00000
> >> >> +
> >> >> +This will connect GDB to QEMU and will load the DTB file and the
> application.
> >> >> +
> >> >> +.. code-block:: none
> >> >> +
> >> >> +     (gdb) continue
> >> >> +
> >> >> +The ``continue`` command will run the executable.
> >> >> +
> >> >> +**Note**: Add ``set scheduler-locking on`` in GDB if you have any
> issues
> >> >> +running the examples.
> >> >> --
> >> >> 2.17.1
> >> >>
> >> > _______________________________________________
> >> > devel mailing list
> >> > devel at rtems.org
> >> > http://lists.rtems.org/mailman/listinfo/devel
>
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