Re: [PATCH 5/5] cpuidle: psci: Prevent domain idlestates until consumers are ready

[Saravana Kannan <saravanak@google.com>]

On Mon, Jun 15, 2020 at 11:50 PM Ulf Hansson <ulf.hansson@linaro.org> wrote:
>
> On Mon, 15 Jun 2020 at 20:06, Saravana Kannan <saravanak@google.com> wrote:
> >
> > On Mon, Jun 15, 2020 at 8:21 AM Ulf Hansson <ulf.hansson@linaro.org> wrote:
> > >
> > > Depending on the SoC/platform, additional devices may be part of the PSCI
> > > PM domain topology. This is the case with 'qcom,rpmh-rsc' device, for
> > > example, even if this is not yet visible in the corresponding DTS-files.
> > >
> > > Without going into too much details, a device like the 'qcom,rpmh-rsc' may
> > > have HW constraints that needs to be obeyed to, before a domain idlestate
> > > can be picked.
> > >
> > > Therefore, let's implement the ->sync_state() callback to receive a
> > > notification when all consumers of the PSCI PM domain providers have been
> > > attached/probed to it. In this way, we can make sure all constraints from
> > > all relevant devices, are taken into account before allowing a domain
> > > idlestate to be picked.
> > >
> > > Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> > > ---
> > >  drivers/cpuidle/cpuidle-psci-domain.c | 14 ++++++++++++++
> > >  1 file changed, 14 insertions(+)
> > >
> > > diff --git a/drivers/cpuidle/cpuidle-psci-domain.c b/drivers/cpuidle/cpuidle-psci-domain.c
> > > index bf527d2bb4b6..b6e9649ab0da 100644
> > > --- a/drivers/cpuidle/cpuidle-psci-domain.c
> > > +++ b/drivers/cpuidle/cpuidle-psci-domain.c
> > > @@ -27,6 +27,7 @@ struct psci_pd_provider {
> > >  };
> > >
> > >  static LIST_HEAD(psci_pd_providers);
> > > +static bool psci_pd_allow_domain_state;
> >
> > Is there ever only 1 device that's probed by this driver? If yes, this
> > is okay. Otherwise, you'll need to handle this on a per device basis.
>
> There is only one device. Subnodes, may exist to describe a
> hierarchical description of the topology of the power-domains [1].

Thanks. In that case:

Acked-by: Saravana Kannan <saravanak@google.com>

-Saravana