problem running on rcar gen3 board (iommu?)

[stsp <stsp2@xxxxxxxxx>]

Hi!

I am trying to run xen on an rcar H3
StarterKit (r8a77951 ES2.0).
First I created a working linux setup.
It uses latest linux git code and is
working well.

Then I built xen, also from git,
at rev 211d8419ef.
Now when runnign xen, I get this:

---

(XEN) ipmmu: /soc/iommu@e6740000: Failed to init IPMMU (-11)
(XEN) ipmmu: /soc/iommu@e7740000: Failed to init IPMMU (-11)
(XEN) ipmmu: /soc/iommu@e6570000: Failed to init IPMMU (-11)
(XEN) ipmmu: /soc/iommu@ff8b0000: Failed to init IPMMU (-11)
(XEN) ipmmu: P2M sharing is not supported in current SoC revision
(XEN) ipmmu: /soc/iommu@e67b0000: Failed to init IPMMU (-19)
(XEN) ipmmu: /soc/iommu@ec670000: Failed to init IPMMU (-11)
(XEN) ipmmu: /soc/iommu@fd800000: Failed to init IPMMU (-11)
(XEN) ipmmu: /soc/iommu@ffc80000: Failed to init IPMMU (-11)
(XEN) ipmmu: /soc/iommu@fe6b0000: Failed to init IPMMU (-11)
(XEN) ipmmu: /soc/iommu@fe6f0000: Failed to init IPMMU (-11)
(XEN) ipmmu: /soc/iommu@febd0000: Failed to init IPMMU (-11)
(XEN) ipmmu: /soc/iommu@fe990000: Failed to init IPMMU (-11)
(XEN) ipmmu: /soc/iommu@ec680000: Failed to init IPMMU (-11)
(XEN) ipmmu: /soc/iommu@e7730000: Failed to init IPMMU (-11)
(XEN) I/O virtualisation disabled
(XEN)
(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) Couldn't configure correctly all the IOMMUs.
(XEN) ****************************************
---

So I added the "iommu=0" option.
Now linux kernel starts but hangs
the entire system somewhere
around the first sdcard transfer.
I see xen is saying this on load:

---

(XEN) Loading d0 kernel from boot module @ 000000007c936000
(XEN) Allocating 1:1 mappings totalling 512MB for dom0:
(XEN) BANK[0] 0x00000050000000-0x00000070000000 (512MB)

---

If it does 1:1 mappings then perhaps
it is supposed to work w/o IOMMU?
But why would it then insist on me
adding "iommu=0"?
And there is a hang and I don't know
if it is related to IOMMU or not...

Any suggestions?
Is rcar H3 board known to work well
with xen?