Booting error in L4android for Exynos 5250.

Youren Shen shenyouren at
Wed May 20 21:30:30 CEST 2015

> > > I'm trying to booting L4Android in Exynos 5250 platform. I got some
> > > questions. If anyone can give me any direction or document, It will be
> > very
> > > helpful.
> > >
> > > 1, How to edit this vbus and devs file to match my platform?
> > > For example, if I want replace the MOUSE in vbus with TOUCHSCREEN, what
> > > should I write to determine the driver of the touchscreen, and the
> > register
> > > address of the driver?
> > > It seems the .hid can assign the driver? And the MMio can remap the
> > address
> > > of the IO for driver?
> >
> > A vbus defines the resources (IRQs and MMIO) for a whole client, i.e.
> > it's not per driver but per client (e.g. L4Linux). For the touchscreen
> > you need to give the MMIO regions and IRQs that the touchscreen driver
> > is using.
> >
> > > 2, As for GUI driver, what the mag and fb-drv do ? Should I write one
> >
> > The fb-drv is the framebuffer driver, i.e. the driver that maps some
> > memory in such a way to the framebuffer hardware that something appears
> > on the screen. mag is a small window manager that makes multiple
> > windows, that you can drag around, out of the single hardware
> > framebuffer.
> >
> > > driver in L4RE or I can reuse the driver in Linux?
> >
> > Reusing the driver from L4Linux is possible but typically framebuffer
> > drivers are reasonable small to be implemented standalone.
> >

For the driver reuse:

I read the User Guide of rearview platform, it seems that the MMIO should
set as the register Address in memory map. And the IRQs should be the
interrupt number + 32.

I know how to write LCD driver and framebuffer in native Linux System. But
for L4Linux, I still have some question. I am not sure how to reuse the
driver of Linux or rewrite the fb-drv.

Here is the situation:

The folder in arch/arm/mach-exynos has plenty code to initial the platform,
so I added config L4_PLATFORM_EXYNOS in arch/l4/Kconfig and
PLATFORMNAME-$(CONFIG_L4_PLATFORM_EXYNOS)  = exynos in arch/l4/Makefile.
However, when build the kernel, there is some error. It seems like the
L4Linux startup invoke some variables defined in Realview or Generic
platform like

NR_IRQS_HW. Is this rectifiable?

I found that there is l4fb.c as driver in driver/video, what's different
with the module in l4/pkg?

And last question, how to run the driver I want to use?

Thank you very much!

Best Regards.
Youren Shen.
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