[Qemu-devel] Query Regarding Device Tree Support in QEMU

[Qemu-devel] Query Regarding Device Tree Support in QEMU

[rajan pathak]

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Hello All,

I have some Query regarding Device tree support in QEMU.

I have gone through for OMAP qemu emulation and noticed a lots of effort
has been
gone for manually mapping the Register set and Hardware representaion into
Device emulation.

Inside include/hw/arm/omap.h lots of code is taken from arch-omap/irq.h.

Can we reduce this effort by using the Device tree compiled Linux Kernel
for different devices?

Thanks
Rajan

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Re: [Qemu-devel] Query Regarding Device Tree Support in QEMU

[Peter Maydell]

On 30 January 2014 14:11, rajan pathak <rajanpatha34@gmail.com> wrote:
> I have some Query regarding Device tree support in QEMU.
>
> I have gone through for OMAP qemu emulation and noticed a lots of effort has
> been
> gone for manually mapping the Register set and Hardware representaion into
> Device emulation.
>
> Inside include/hw/arm/omap.h lots of code is taken from arch-omap/irq.h.
>
> Can we reduce this effort by using the Device tree compiled Linux Kernel for
> different devices?

The device tree is just the way that Linux splits up its
data structures which tell it what the hardware looks like from
its code. QEMU still has to model what the actual hardware does,
so it can run any guest.

It is possible in theory in some specific situations to get
enough information from a device tree file to assemble a
set of QEMU device models into a board or SoC model. However
this isn't in general doable, because the device tree has
the information the kernel needs, which overlaps but isn't
the same as what QEMU needs.

thanks
-- PMM