Messages in this thread | | | Date | Wed, 16 Feb 2022 14:39:26 +0000 | From | Marc Zyngier <> | Subject | Re: [PATCH v5 1/3] cpuidle: psci: Call cpu_cluster_pm_enter() on the last CPU |
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On 2022-02-16 13:28, Shawn Guo wrote: > Make a call to cpu_cluster_pm_enter() on the last CPU going to low > power > state (and cpu_cluster_pm_exit() on the firt CPU coming back), so that > platforms can be notified to set up hardware for getting into the > cluster > low power state. > > Signed-off-by: Shawn Guo <shawn.guo@linaro.org> > --- > drivers/cpuidle/cpuidle-psci.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/drivers/cpuidle/cpuidle-psci.c > b/drivers/cpuidle/cpuidle-psci.c > index b51b5df08450..c748c1a7d7b1 100644 > --- a/drivers/cpuidle/cpuidle-psci.c > +++ b/drivers/cpuidle/cpuidle-psci.c > @@ -37,6 +37,7 @@ struct psci_cpuidle_data { > static DEFINE_PER_CPU_READ_MOSTLY(struct psci_cpuidle_data, > psci_cpuidle_data); > static DEFINE_PER_CPU(u32, domain_state); > static bool psci_cpuidle_use_cpuhp; > +static atomic_t cpus_in_idle; > > void psci_set_domain_state(u32 state) > { > @@ -67,6 +68,14 @@ static int __psci_enter_domain_idle_state(struct > cpuidle_device *dev, > if (ret) > return -1; > > + if (atomic_inc_return(&cpus_in_idle) == num_online_cpus()) { > + ret = cpu_cluster_pm_enter(); > + if (ret) { > + ret = -1; > + goto dec_atomic; > + } > + } > + > /* Do runtime PM to manage a hierarchical CPU toplogy. */ > rcu_irq_enter_irqson(); > if (s2idle) > @@ -88,6 +97,10 @@ static int __psci_enter_domain_idle_state(struct > cpuidle_device *dev, > pm_runtime_get_sync(pd_dev); > rcu_irq_exit_irqson(); > > + if (atomic_read(&cpus_in_idle) == num_online_cpus()) > + cpu_cluster_pm_exit(); > +dec_atomic: > + atomic_dec(&cpus_in_idle); > cpu_pm_exit(); > > /* Clear the domain state to start fresh when back from idle. */
Is it just me, or does anyone else find it a bit odd that a cpuidle driver calls back into the core cpuidle code to generate new events?
Also, why is this PSCI specific? I would assume that the core cpuidle code should be responsible for these transitions, not a random cpuidle driver.
Thanks,
M. -- Jazz is not dead. It just smells funny...
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