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

[Ian Campbell]

On Thu, 2015-01-15 at 15:55 +0100, Thierry Reding wrote:
> On Wed, Jan 14, 2015 at 08:58:41AM +0000, Ian Campbell wrote:
> > On Wed, 2015-01-14 at 08:57 +0100, Thierry Reding wrote:
> > > > 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.
> > 
> > Will do. Could you offer a S-o-b for it please so I can pick it up.
> 
> Sure:
> 
> Signed-off-by: Thierry Reding <treding at nvidia.com>

Thanks!

> > > 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.
> > 
> > Hrm, I'm not sure how this all fits together, it's not a problem I've
> > noted before.
> > 
> > FWIW I think cpu_off and cpu_suspend are optional in PSCI v0.1 so an
> > initial version doesn't necessarily need to implement them (sunxi
> > doesn't for example), but as you say they do enable useful features.
> 
> I think when I tried last time, without disable the cpuidle driver
> things would hang at boot. I would expect that problem to exist for
> any board. Perhaps you've disabled PM_SLEEP in your config?

I don't think so:
# grep PM_SLEEP /boot/config-3.18.0-trunk-armmp-lpae 
CONFIG_PM_SLEEP=y
CONFIG_PM_SLEEP_SMP=y
CONFIG_PM_SLEEP_DEBUG=y

I don't see anything about cpuidle in dmesg either.

Did you perhaps mean CPU_IDLE rather than PM_SLEEP because:
# CONFIG_CPU_IDLE is not set

Ian.