RKI Image for Raspberry PI 2

[Pavel Pisa]

Hello Mudit,


On Tuesday 24 of May 2016 16:17:07 Mudit Jain wrote:
> Hi Pavel,
>
> I have pulled your branch and I am able to build the rki.bin using the
> following commands.
>
> mkdir b-rpi2
> cd b-rpi2
> ../rtems/configure --target=arm-rtems4.12 --prefix=$sandbox/rtems-4.12
>  --enable-rtems-inlines --disable-multiprocessing --enable-cxx
> --enable-rdbg --enable-maintainer-mode --enable-tests=samples
> --enable-networking --enable-posix --disable-itron --disable-ada
> --disable-expada --disable-multilib --disable-docs
>  --enable-rtemsbsp="raspberrypi2"
> make
> make install
> cd ../rki
> waf configure --rtems=$sandbox/rtems-4.12
> --rtems-tools=/home/mudit/Desktop/sandbox/rtems-4.12 --rtems-version=4.12
> --rtems-bsps=arm/raspberrypi2
> waf
>
> It succesfully builds rki.bin.
> This binary is renamed and put in as kernel.img.
>
> I previously had an image of raspbian-jessie-lite on the card. I replaced
> the kernel.img in the boot partition with the kernel.img that was prepared
> by the above process.
> It had deleted the previous kernel.img and still it was somehow booting
> into raspbian.
>
> Raspbian Jessie Lite was downloaded from -
> https://www.raspberrypi.org/downloads/raspbian/
>
> Is the hash of the kernel saved, and during the boot up process, if the
> kernel is not authenticated, then a backup kernel takes over ?
>

if I remember well then RPi2 boots kernel7.img by default.
But you can specify image in "config.txt" file. Comment
old kernel line (if found there) by prepending a hash character '#'.
Then set 

  kernel=ticker.bin

or ticker.img. On Rpi 1 exact one to one copy of memory from 0x8000 is 
included in ticker.bin. I am not sure about RPi2, because it boots
linux packed in zImage by default. So I am not sure if plain binary
file can be booted. If the real zImage is required then there
is "mkknlimg" utility which could help, is referenced in some
U-boot for RPi2 discussion, but I am not sure if it is the right tool.
Other option is to use Linux kernel sources for bzImage decompressor
shim.

It is a question for the other developers and contributors
who worked on RETEM for RPi2 already. I have not been in contact
with them, my last GSoC student and I have tested RTEMS
only on RPi version 1.

Probably Alan Cudmore knows more about BSP state and testing
on RPi2.

best wishes,

             Pavel