Re: [PATCH 4/4] PM / Domains: Propagate performance state updates

Viresh Kumar
2018-11-21T05:16:32Z

On 21-11-18, 10:33, Rajendra Nayak wrote:
> Hi Viresh,
>
> On 11/5/2018 12:06 PM, Viresh Kumar wrote:
> > This commit updates genpd core to start propagating performance state
> > updates to master domains that have their set_performance_state()
> > callback set.
> >
> > A genpd handles two type of performance states now. The first one is the
> > performance state requirement put on the genpd by the devices and
> > sub-domains under it, which is already represented by
> > genpd->performance_state. The second type, introduced in this commit, is
> > the performance state requirement(s) put by the genpd on its master
> > domain(s). There is a separate value required for each master that the
> > genpd has and so a new field is added to the struct gpd_link
> > (link->performance_state), which represents the link between a genpd and
> > its master. The struct gpd_link also got another field
> > prev_performance_state, which is used by genpd core as a temporary
> > variable during transitions.
> >
> > We need to propagate setting performance state while powering-on a genpd
> > as well, as we ignore performance state requirements from sub-domains
> > which are powered-off. For this reason _genpd_power_on() also received
> > the additional parameter, depth, which is used for hierarchical locking
> > within genpd.
> >
> > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> > ---
> > drivers/base/power/domain.c | 107 +++++++++++++++++++++++++++++-------
> > include/linux/pm_domain.h | 4 ++
> > 2 files changed, 92 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> > index 6d2e9b3406f1..81e02c5f753f 100644
> > --- a/drivers/base/power/domain.c
> > +++ b/drivers/base/power/domain.c
> > @@ -239,28 +239,86 @@ static void genpd_update_accounting(struct generic_pm_domain *genpd)
> > static inline void genpd_update_accounting(struct generic_pm_domain *genpd) {}
> > #endif
> > +static int _genpd_reeval_performance_state(struct generic_pm_domain *genpd,
> > + unsigned int state, int depth);
> > +
> > static int _genpd_set_performance_state(struct generic_pm_domain *genpd,
> > - unsigned int state)
> > + unsigned int state, int depth)
> > {
> > + struct generic_pm_domain *master;
> > + struct gpd_link *link;
> > + unsigned int mstate;
> > int ret;
> > if (!genpd_status_on(genpd))
> > goto out;
>
> This check here would mean we only propogate performance state
> to masters if the genpd is ON?

Yeah, isn't that what should we do anyway? It is similar to clk-enable
etc. Why increase the reference count if the device isn't enabled and
isn't using the clock ?

Also you can see that I have updated the genpd power-on code to start
propagation to make sure we don't miss anything.

--
viresh