On Thu, 24 Oct 2019 at 18:33, Sudeep Holla <sudeep.holla@xxxxxxx> wrote:
>
> On Thu, Oct 10, 2019 at 01:39:36PM +0200, Ulf Hansson wrote:
> > In case we have succeeded to attach a CPU to its PM domain, let's deploy
> > runtime PM support for the corresponding attached device, to allow the CPU
> > to be powered-managed accordingly.
> >
> > To set the triggering point for when runtime PM reference counting should
> > be done, let's store the index of deepest idle state for the CPU in the per
> > CPU struct. Then use this index to compare the selected idle state index
> > when entering idle, as to understand whether runtime PM reference counting
> > is needed or not.
> >
> > Note that, from the hierarchical point view, there may be good reasons to
> > do runtime PM reference counting even on shallower idle states, but at this
> > point this isn't supported, mainly due to limitations set by the generic PM
> > domain.
> >
> > Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> > ---
> > drivers/cpuidle/cpuidle-psci.c | 21 +++++++++++++++++++--
> > 1 file changed, 19 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
> > index 1510422c7a53..0919b40c1a85 100644
> > --- a/drivers/cpuidle/cpuidle-psci.c
> > +++ b/drivers/cpuidle/cpuidle-psci.c
> > @@ -16,6 +16,7 @@
> > #include <linux/of.h>
> > #include <linux/of_device.h>
> > #include <linux/psci.h>
> > +#include <linux/pm_runtime.h>
> > #include <linux/slab.h>
> >
> > #include <asm/cpuidle.h>
> > @@ -25,6 +26,7 @@
> >
> > struct psci_cpuidle_data {
> > u32 *psci_states;
> > + u32 rpm_state_id;
> > struct device *dev;
> > };
> >
> > @@ -50,14 +52,28 @@ static int psci_enter_idle_state(struct cpuidle_device *dev,
> > struct cpuidle_driver *drv, int idx)
> > {
> > int ret;
> > - u32 *states = __this_cpu_read(psci_cpuidle_data.psci_states);
> > - u32 state = psci_get_domain_state();
> > + struct psci_cpuidle_data *data = this_cpu_ptr(&psci_cpuidle_data);
> > + u32 *states = data->psci_states;
> > + struct device *pd_dev = data->dev;
> > + bool runtime_pm = (pd_dev && data->rpm_state_id == idx);
> > + u32 state;
>
> Wonder if we can have separate psci_enter_idle_state for OSI mode so
> that all these runtime extra check can be reduced ? It will also make
> sure there's no additional latency for PC mode because of OSI.
Good idea, that's the plan. See previous answer.
Perhaps if I add a patch on top, implementing your suggestion, would
you be happy with that?
Kind regards
Uffe
