missing timer in dts: how to deal ?

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

Hello,
the i.mx6sx SoC I got working recently includes a single-core cortex A9 CPU.
As I understand it, all A9 CPUs have the TWD timer, and this is what we
use for delay and hardclock(). But the imx6sx.dtsi file is missing the
TWD node ("arm,cortex-a9-twd-timer"), while the imx6qdl.dtsi includes it.

How can we deal with this ?
- add the twd node to our copy of the device tree (this is what I did
  in my tree but didn't commit it). But this patches a file in sys/external
- fake a node in the in-memory fdt early in boot (but is there a way to do
  this ? I couldn't find anything related to fake nodes in dev/fdt/ or
  dev/ofw/)
- add a non-fdt attachement for TWD (and need to find where and when to
  attach it - maybe as a child of
  cpus0 at simplebus0

Any though from port-arm experts ?

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--