[Letux-kernel] [Lenny400] L4Re/Fiasco.OC on the Letux 400
H. Nikolaus Schaller
hns at goldelico.com
Tue Apr 17 21:34:32 CEST 2018
> Am 17.04.2018 um 00:08 schrieb Paul Boddie <paul at boddie.org.uk>:
> I haven't been able to direct any real attention to the Letux 400 for quite
> some time, but recently I managed to port the L4 Runtime Environment and
> Fiasco.OC microkernel to the Ben NanoNote, most of the work already having
> been done by the L4Re/Fiasco.OC developers and some people who ported these
> things to the MIPS architecture.
> Here is a summary of that work, with a collection of articles for anyone
> *really* interested in the details:
> Having done this, it did occur to me that I could give the Letux 400 some
> attention in this regard. As everyone reading this will know, the Ben uses the
> JZ4720 (a JZ4740 variant) whereas the Letux uses the mysterious JZ4730. But
> since we gained some experience with "modernising" Linux support, David with
> his "evolved" kernel and myself with some attempts to test functionality
> within the old kernel and then in making a tentative modern kernel (which I
> still haven't tested)
same for me... I just keep rebasing it on latest upstream release-candidates.
And doing a test compilation.
What I didn't find time for was to open the L400 and solder a connector
for access to the serial console. This seems to be the first step before
testing anything. Even if the device boots the very old kernel from flash.
> , it seemed reasonable to see what could be done.
> To keep this message short, I can report that I did indeed get Fiasco.OC to
> boot on the Letux, and I have written L4Re support for the CPM (clock and
> power management), GPIO, LCD and PWM peripherals. The LCD support works within
> the driver framework used by the framebuffer driver, and so framebuffer
> programs can apparently just use the display without any special effort.
> I have made my patches against the L4Re/Fiasco.OC repository available here:
> You may wonder what this has to do with these lists, particularly the lenny400
> list, which is largely concerned with Debian root filesystems and suitable
> Linux kernels. And until I send this, I don't even know if the mipsbook-devel
> list is even functioning any more.
As you indicate it is important to know that your kernel patches can not
be completely wrong :) So it is another stimulus to finally try to boot.
> I would like to think that this opens another door to modern software
> offerings for the Letux 400, even though work is needed to provide support for
> other aspects of the hardware and to construct a suitable software framework
> for "normal" use of the device. I intend to investigate things like Genode for
> the latter task:
> Meanwhile, I think that these technologies are also relevant for other Letux
> products. It might be interesting to consider running something like QtMoko on
> top of a software framework rooted in these technologies. Qt is apparently
> supported by Genode, and so it might not be so absurd to consider a relatively
> lightweight environment combining the two.
Oh, that would be an interesting task. What I don't know is if the current
QtMoko has any hard coded focus on armhf. So switching to mipsel (soft-float)
may be easy or may not...
> Anyway, I hope this is of interest to someone out there!
BR and thanks for sharing,
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