[PATCH] arm: introduce a DTS for Xen unprivileged virtual machines

On Thu, 2012-09-20 at 13:39 +0100, Stefano Stabellini wrote:

On Thu, 20 Sep 2012, Ian Campbell wrote:

quoted

quoted

Versatile Express is flexible enough to be a good base for our own
virtual machine platform, especially if the maintainers keep an eye on
getting everything through DT and not expecting devices just to be there
;-)

Perhaps what we want is a stricter subset of the stuff in mach-vexpress
then. But if so then this should be expressed both in the DT and in the
code, not just papered over by declaring things compatible when they are
not.

But it is already expressed in the DT, by removing all the device nodes
we don't emulated. And it is already expressed in the code, by fully
discovering peripherals via DT, therefore not trying to initialize
non-present devices.

Sorry on second look most of the non-DT stuff is part of the non-DT
vexpress support code in the same file.

There are some exceptions though:

v2m_reset and v2m_power_off don't refer to DT and touch system
peripherals directly.

v2m_dt_map_io falls back to v2m_io_desc if there is no rs1 node (which I
think we don't have?) 

v2m_clk_init is called from v2m_dt_timer_init (I think you may have
fixed this one).

quoted

quoted

quoted

quoted

+	gic: interrupt-controller at 2c001000 {
+		compatible = "arm,cortex-a9-gic";

Don't we mean "arm,cortex-a15-gic" here? That's what we actually
provide. I'm not sure how the a9 and a15 differ.

The GIC that comes with vexpress is a9 compatible.

The GIC which Xen emulates is the one which matters here though, and
that is an a15.

The a15 gic is still a9 compatible. OK to be precise I am going to add
"arm,cortex-a15-gic", but I cannot really remove "arm,cortex-a9-gic".

I think A9 is GIC v1 and A15 is GIC v2, with the primary difference
being the alignment of the memory mapped registers, but I'm not totally
sure of that.

A bunch of places do use "arm,cortex-a15-gic", "arm,cortex-a9-gic" so
you are probably right that this is the proper answer.

Ian.