[GSoC 2014] Interested in ARM bringup tasks

[Ganbold Tsagaankhuu]

Alexander,


On Mon, Mar 17, 2014 at 7:19 AM, Alexander Tarasikov <
alexander.tarasikov at gmail.com> wrote:

> Hello, FreeBSD community!
>
> I am interested in participating in GSoC this year and I'd like to
> pick up one of the tasks related to porting FreeBSD to new
> architectures. I'm now doing my master's degree in software
> engineering at the "Higher School of Economics" in Moscow.
>
> Since I love ARM and smartphones, I've chosen the project to port
> FreeBSD to a smartphone. If that task is already occupied (which
> doesn't seem so), I would be happy to pick up another task suggested
> by the community.
>
> I want to port FreeBSD to the Sony Xperia Z phone. This phone has the
> Qualcomm APQ8064 SoC which is used in a large number of smartphones,
> including Google Nexus 4. Besides, Qualcomm SoCs are developed
> incrementally so there's a high chance that the code for current
> generation of chips will benefit future revisions as well.
>

Interesting. I'm not quite sure how accessible is some pins like uart in
Experia Z.
I have it here, but I still didn't try to open it yet to see the pins etc.
Probably you meant here some embedded boards like ifc6410.
Plus ifc6410 has docs so that could be useful too.



>
> It is known that debugging like JTAG and flash recovery is not
> available on consumer devices because of DRM and general love for
> obfuscation among the vendors. Therefore, to prevent bricking the
> device,


That is the hell, it seems Qualcomm uses lauterbach jtag adapter in that
case.
I and my friend and also some people have tried some adapters like
flyswatter2 with ifc6410, still no luck.

I suggest using the chainloading approach, that is using the
> bootloader that ships with the device and pretend to be a linux image.
>

That can be done. Their bootloader like maybe LK in case of ifc6410 can
boot freebsd kernel.
Actually I did that for ifc6410.


>
> For the mid-term I want to port the u-boot bootloader and add the
> support for accessing the microSD card from it. The u-boot will be
> flashed to the device instead of the linux kernel.
>


That could be cool.


>
> Since the proprietary bootloader already initializes the display (we
> can also port linux driver to u-boot), it should be possible, at least
> during the initial stage, to use a simple driver in FreeBSD that would
> write to the framebuffer allocated by the bootloader or only write the
> framebuffer address to the display controller.
>


That is nice. However first we need uart driver, then either usb ehci, mmc
or sata driver needs to mount rootfs in order to boot freebsd to multiuser
mode. I already have timer driver and minimal console driver so it makes
booting little bit easier.


>
> In the past I've successfully ported linux to an Intel XScale-based
> Asus P525 smartphone, ported Android with all hardware working to boot
> from NAND on the Sony Xperia X1 phone and have ported various boards
> from OEM to vanilla kernel trees. Recently I've experimented with the
> XNU kernel (the one which is used in the fruity operating system) and
> ported it to the OMAP5 board. So I think I'll be able to pull it off.
>

Cool. In case of android or linux there are many people working on various
stuffs so in most case drivers are either written or somebody has got
started working on particular driver already. For FreeBSD case it is
different. You maybe know that very few people are working in case of ARM
platform bringup, so we need more developers and I'm happy that you decided
to work on this direction.

Ganbold



>
> Have a nice day!
>
> --
> Regards, Alexander
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