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); + 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
