Hi Thierry,
I needed to boot my Jetson in NS mode (in order to boot Xen) and was investigating the possibility of PSCI support when I discovered that you had already started on it[0]. Hurrah!
I cherry-picked the relevant commit onto u-boot-tegra#master and added a few more patches and now it boots correctly for me, both running Xen (some Xen side patches are needed too) and native Linux.
The main things which was needed was to rebase for some recent Kconfig changes relating to virt and nonsec mode and to arrange for the RAM used by the secure code to be reserved in the FDT. I also reserved the RAM using the hardware MC_SECURITY_CFG registers for good measure.
I also pushed my tree to gitorious: https://gitorious.org/ijc/u-boot jetson-psci-v1
I would Ack your patch, but I don't think you've posted it and it has no S-o-b so that would seem a bit premature/rude of me. For the same reason I've not actually included it in the series posted (but it is in the gitorious branch).
FWIW I think you could drop your stub versions of psci_cpu_off and psci_cpu_suspend (assuming you don't want to implement them) since the common code has stubs.
Albert, I've CCd you on a couple of patches which touch common ARM code. Nothing too major I think.
Cheers, Ian.
[0] https://github.com/thierryreding/u-boot/commit/5996d2b0dea2953ae8881f40b7f85...