On Thu, 5 Dec 2019 at 19:07, Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> wrote: > > On Thu, Dec 05, 2019 at 11:33:30AM +0100, Ulf Hansson wrote: > > When the hierarchical CPU topology is used and when a CPU is put offline, > > that CPU prevents its PM domain from being powered off, which is because > > genpd observes the corresponding attached device as being active from a > > runtime PM point of view. Furthermore, any potential master PM domains are > > also prevented from being powered off. > > > > To address this limitation, let's add add a new CPU hotplug state > > (CPUHP_AP_CPU_PM_STARTING) and register up/down callbacks for it, which > > allows us to deal with runtime PM accordingly. > > > > Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> > > --- > > > > Lorenzo, Sudeep, Rafael, Daniel, > > > > Note that, this patch is based upon a recently posted series [1] and the intent > > is to queue it on top. I can fold it into the series and resend it all, if that > > makes it easier for people. Just tell me what you prefer. > > > > Kind regards > > Uffe > > > > [1] > > https://patchwork.kernel.org/cover/11263735/ > > > > --- > > drivers/cpuidle/cpuidle-psci.c | 45 +++++++++++++++++++++++++++++++++- > > include/linux/cpuhotplug.h | 1 + > > 2 files changed, 45 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c > > index 835c7c3aa118..46b481c524cc 100644 > > --- a/drivers/cpuidle/cpuidle-psci.c > > +++ b/drivers/cpuidle/cpuidle-psci.c > > @@ -8,6 +8,7 @@ > > > > #define pr_fmt(fmt) "CPUidle PSCI: " fmt > > > > +#include <linux/cpuhotplug.h> > > #include <linux/cpuidle.h> > > #include <linux/cpumask.h> > > #include <linux/cpu_pm.h> > > @@ -31,6 +32,7 @@ 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; > > > > void psci_set_domain_state(u32 state) > > { > > @@ -72,6 +74,44 @@ static int psci_enter_domain_idle_state(struct cpuidle_device *dev, > > return ret; > > } > > > > +static int psci_idle_cpuhp_up(unsigned int cpu) > > +{ > > + struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev); > > + > > + if (pd_dev) > > + pm_runtime_get_sync(pd_dev); > > + > > + return 0; > > +} > > + > > +static int psci_idle_cpuhp_down(unsigned int cpu) > > +{ > > + struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev); > > + > > + if (pd_dev) { > > + pm_runtime_put_sync(pd_dev); > > + /* Clear domain state to start fresh at next online. */ > > + psci_set_domain_state(0); > > + } > > + > > + return 0; > > +} > > + > > +static void psci_idle_init_cpuhp(void) > > +{ > > + int err; > > + > > + if (!psci_cpuidle_use_cpuhp) > > + return; > > + > > + err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING, > > + "cpuidle/psci:online", > > + psci_idle_cpuhp_up, > > + psci_idle_cpuhp_down); > > I would make it a cpuhp_setup_state() call and remove > > if (cpu_online(cpu)) > pm_runtime_get_sync_dev(dev); > > in check in psci_dt_attach_cpu(). > > Lorenzo Thanks for the suggestion, but that doesn't work when CONFIG_CPU_HOTPLUG is unset. As a matter of fact, I just realized that I haven't tried to compile without that Kconfig option. I should probably add a stub for psci_idle_init_cpuhp() to address that. > > > + if (err) > > + pr_warn("Failed %d while setup cpuhp state\n", err); > > +} > > + > > static int psci_enter_idle_state(struct cpuidle_device *dev, > > struct cpuidle_driver *drv, int idx) > > { > > @@ -161,9 +201,11 @@ static int __init psci_dt_cpu_init_idle(struct cpuidle_driver *drv, > > } > > > > /* Manage the deepest state via a dedicated enter-function. */ > > - if (dev) > > + if (dev) { > > drv->states[state_count - 1].enter = > > psci_enter_domain_idle_state; > > + psci_cpuidle_use_cpuhp = true; > > + } > > > > data->dev = dev; > > > > @@ -285,6 +327,7 @@ static int __init psci_idle_init(void) > > goto out_fail; > > } > > > > + psci_idle_init_cpuhp(); > > return 0; > > > > out_fail: > > diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h > > index e51ee772b9f5..01f04ed6ad92 100644 > > --- a/include/linux/cpuhotplug.h > > +++ b/include/linux/cpuhotplug.h > > @@ -95,6 +95,7 @@ enum cpuhp_state { > > CPUHP_AP_OFFLINE, > > CPUHP_AP_SCHED_STARTING, > > CPUHP_AP_RCUTREE_DYING, > > + CPUHP_AP_CPU_PM_STARTING, > > CPUHP_AP_IRQ_GIC_STARTING, > > CPUHP_AP_IRQ_HIP04_STARTING, > > CPUHP_AP_IRQ_ARMADA_XP_STARTING, > > -- > > 2.17.1 > > Kind regards Uffe
