[Skiboot] [PATCH v3] core: POWER9 implement OPAL_SIGNAL_SYSTEM_RESET

[Nicholas Piggin]

On Mon, 18 Sep 2017 20:47:48 +1000
Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote:

> On Mon, 2017-09-18 at 17:45 +1000, Nicholas Piggin wrote:
> > This implements OPAL_SIGNAL_SYSTEM_RESET, using scom registers to
> > quiesce the target thread and raise a system reset exception on it.
> > 
> > This has been tested on DD1 and DD2 including ESL=0 and ESL=1 power
> > saving modes.
> > 
> > It will have to be tested with deep idle states when those are enabled.
> > If those cannot be supported, it should be possible to work around in
> > Linux.
> > 
> > Signed-off-by: Nicholas Piggin <npiggin at gmail.com>  
> 
> The special wakeup stuff should have its own separate "module" that
> refcounts how many requests are in flight. Vaidy has some DTS sensor
> stuff for Google that uses it too afaik.
> 
> As for P8, there are serious issues with broken SRR1 bits iirc...

I've talked with Vaidy about this. Their stuff is not quite ready,
so he's happy if this goes in first.

I have re-worked so it has some locking and refcounting and a more
general API, and moved it to core/direct-controls.c. Vaidy's work
on the idle states can easily hook into it.

It's only P9 for now, but set up so we can bring some of the P8
fast-reboot.c and host services code into here when we have some
free bandwidth (I have a few patches but no bandwidth to test them
ATM).

Thanks,
Nick