[U-Boot] [PATCH v1 0/4] Jetson-TK1 support for PSCI

[Thierry Reding]

On Tue, Jan 13, 2015 at 07:44:50PM +0000, Ian Campbell wrote:
> 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.

Great, those were all things that I had wanted to do but never got
around to.

> 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).

Feel free to take ownership of that patch. I currently don't have the
time to work on this and it seems you've made good progress on it.

It could probably use some cleanup because there's a bit of debug output
still in there. Also...

> 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.

... I'd think you'd need to implement these so that you can get proper
suspend/resume support in the kernel. I've had to disable cpuidle (via
#undef CONFIG_PM_SLEEP in arch/arm/mach-tegra/cpuidle-tegra114.c) in the
kernel to make that code not powergate CPUs. Ideally I think the kernel
would check that it's running with PSCI support and disable the cpuidle
driver. Maybe that could be done by introducing a new cpuidle driver
that checks for PSCI availability and uses it when present.

Adding Stephen and Tom for visibility.

Thanks,
Thierry
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