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![Ulf Hansson](/assets/img/avatar_default.png)
When PSCI OSI mode is supported the syscore flag is set for the CPU devices that becomes attached to their PM domains (genpds). In the suspend-to-idle case, we call dev_pm_genpd_suspend|resume() to allow genpd to properly manage the power-off/on operations (pick an idlestate and manage the on/off notifications). For suspend-to-ram, dev_pm_genpd_suspend|resume() is currently not being called, which causes a problem that the genpd on/off notifiers do not get sent as expected. This prevents the platform-specific operations from being executed, typically needed just before/after the boot CPU is being turned off/on. To deal with this problem, let's register a syscore ops for cpuidle-psci when PSCI OSI mode is being used and call dev_pm_genpd_suspend|resume() from them. In this way, genpd regains control of the PM domain topology and then sends the on/off notifications when it's appropriate. Reported-by: Maulik Shah <quic_mkshah@quicinc.com> Suggested-by: Maulik Shah <quic_mkshah@quicinc.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Tested-by: Maulik Shah <quic_mkshah@quicinc.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
455 lines
10 KiB
C
455 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* PSCI CPU idle driver.
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*
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* Copyright (C) 2019 ARM Ltd.
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* Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
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*/
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#define pr_fmt(fmt) "CPUidle PSCI: " fmt
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#include <linux/cpuhotplug.h>
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#include <linux/cpu_cooling.h>
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#include <linux/cpuidle.h>
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#include <linux/cpumask.h>
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#include <linux/cpu_pm.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/psci.h>
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#include <linux/pm_domain.h>
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#include <linux/pm_runtime.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/syscore_ops.h>
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#include <asm/cpuidle.h>
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#include "cpuidle-psci.h"
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#include "dt_idle_states.h"
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struct psci_cpuidle_data {
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u32 *psci_states;
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struct device *dev;
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};
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static DEFINE_PER_CPU_READ_MOSTLY(struct psci_cpuidle_data, psci_cpuidle_data);
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static DEFINE_PER_CPU(u32, domain_state);
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static bool psci_cpuidle_use_cpuhp;
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void psci_set_domain_state(u32 state)
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{
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__this_cpu_write(domain_state, state);
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}
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static inline u32 psci_get_domain_state(void)
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{
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return __this_cpu_read(domain_state);
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}
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static inline int psci_enter_state(int idx, u32 state)
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{
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return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter, idx, state);
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}
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static int __psci_enter_domain_idle_state(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int idx,
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bool s2idle)
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{
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struct psci_cpuidle_data *data = this_cpu_ptr(&psci_cpuidle_data);
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u32 *states = data->psci_states;
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struct device *pd_dev = data->dev;
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u32 state;
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int ret;
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ret = cpu_pm_enter();
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if (ret)
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return -1;
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/* Do runtime PM to manage a hierarchical CPU toplogy. */
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rcu_irq_enter_irqson();
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if (s2idle)
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dev_pm_genpd_suspend(pd_dev);
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else
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pm_runtime_put_sync_suspend(pd_dev);
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rcu_irq_exit_irqson();
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state = psci_get_domain_state();
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if (!state)
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state = states[idx];
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ret = psci_cpu_suspend_enter(state) ? -1 : idx;
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rcu_irq_enter_irqson();
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if (s2idle)
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dev_pm_genpd_resume(pd_dev);
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else
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pm_runtime_get_sync(pd_dev);
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rcu_irq_exit_irqson();
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cpu_pm_exit();
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/* Clear the domain state to start fresh when back from idle. */
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psci_set_domain_state(0);
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return ret;
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}
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static int psci_enter_domain_idle_state(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int idx)
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{
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return __psci_enter_domain_idle_state(dev, drv, idx, false);
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}
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static int psci_enter_s2idle_domain_idle_state(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int idx)
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{
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return __psci_enter_domain_idle_state(dev, drv, idx, true);
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}
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static int psci_idle_cpuhp_up(unsigned int cpu)
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{
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struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev);
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if (pd_dev)
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pm_runtime_get_sync(pd_dev);
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return 0;
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}
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static int psci_idle_cpuhp_down(unsigned int cpu)
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{
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struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev);
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if (pd_dev) {
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pm_runtime_put_sync(pd_dev);
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/* Clear domain state to start fresh at next online. */
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psci_set_domain_state(0);
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}
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return 0;
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}
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static void psci_idle_syscore_switch(bool suspend)
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{
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bool cleared = false;
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struct device *dev;
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int cpu;
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for_each_possible_cpu(cpu) {
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dev = per_cpu_ptr(&psci_cpuidle_data, cpu)->dev;
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if (dev && suspend) {
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dev_pm_genpd_suspend(dev);
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} else if (dev) {
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dev_pm_genpd_resume(dev);
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/* Account for userspace having offlined a CPU. */
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if (pm_runtime_status_suspended(dev))
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pm_runtime_set_active(dev);
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/* Clear domain state to re-start fresh. */
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if (!cleared) {
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psci_set_domain_state(0);
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cleared = true;
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}
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}
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}
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}
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static int psci_idle_syscore_suspend(void)
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{
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psci_idle_syscore_switch(true);
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return 0;
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}
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static void psci_idle_syscore_resume(void)
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{
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psci_idle_syscore_switch(false);
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}
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static struct syscore_ops psci_idle_syscore_ops = {
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.suspend = psci_idle_syscore_suspend,
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.resume = psci_idle_syscore_resume,
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};
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static void psci_idle_init_cpuhp(void)
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{
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int err;
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if (!psci_cpuidle_use_cpuhp)
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return;
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register_syscore_ops(&psci_idle_syscore_ops);
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err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING,
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"cpuidle/psci:online",
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psci_idle_cpuhp_up,
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psci_idle_cpuhp_down);
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if (err)
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pr_warn("Failed %d while setup cpuhp state\n", err);
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}
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static int psci_enter_idle_state(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int idx)
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{
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u32 *state = __this_cpu_read(psci_cpuidle_data.psci_states);
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return psci_enter_state(idx, state[idx]);
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}
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static const struct of_device_id psci_idle_state_match[] = {
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{ .compatible = "arm,idle-state",
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.data = psci_enter_idle_state },
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{ },
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};
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int psci_dt_parse_state_node(struct device_node *np, u32 *state)
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{
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int err = of_property_read_u32(np, "arm,psci-suspend-param", state);
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if (err) {
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pr_warn("%pOF missing arm,psci-suspend-param property\n", np);
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return err;
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}
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if (!psci_power_state_is_valid(*state)) {
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pr_warn("Invalid PSCI power state %#x\n", *state);
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return -EINVAL;
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}
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return 0;
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}
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static int psci_dt_cpu_init_topology(struct cpuidle_driver *drv,
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struct psci_cpuidle_data *data,
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unsigned int state_count, int cpu)
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{
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/* Currently limit the hierarchical topology to be used in OSI mode. */
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if (!psci_has_osi_support())
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return 0;
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data->dev = psci_dt_attach_cpu(cpu);
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if (IS_ERR_OR_NULL(data->dev))
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return PTR_ERR_OR_ZERO(data->dev);
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/*
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* Using the deepest state for the CPU to trigger a potential selection
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* of a shared state for the domain, assumes the domain states are all
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* deeper states.
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*/
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drv->states[state_count - 1].enter = psci_enter_domain_idle_state;
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drv->states[state_count - 1].enter_s2idle = psci_enter_s2idle_domain_idle_state;
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psci_cpuidle_use_cpuhp = true;
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return 0;
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}
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static int psci_dt_cpu_init_idle(struct device *dev, struct cpuidle_driver *drv,
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struct device_node *cpu_node,
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unsigned int state_count, int cpu)
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{
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int i, ret = 0;
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u32 *psci_states;
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struct device_node *state_node;
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struct psci_cpuidle_data *data = per_cpu_ptr(&psci_cpuidle_data, cpu);
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state_count++; /* Add WFI state too */
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psci_states = devm_kcalloc(dev, state_count, sizeof(*psci_states),
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GFP_KERNEL);
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if (!psci_states)
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return -ENOMEM;
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for (i = 1; i < state_count; i++) {
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state_node = of_get_cpu_state_node(cpu_node, i - 1);
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if (!state_node)
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break;
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ret = psci_dt_parse_state_node(state_node, &psci_states[i]);
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of_node_put(state_node);
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if (ret)
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return ret;
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pr_debug("psci-power-state %#x index %d\n", psci_states[i], i);
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}
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if (i != state_count)
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return -ENODEV;
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/* Initialize optional data, used for the hierarchical topology. */
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ret = psci_dt_cpu_init_topology(drv, data, state_count, cpu);
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if (ret < 0)
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return ret;
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/* Idle states parsed correctly, store them in the per-cpu struct. */
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data->psci_states = psci_states;
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return 0;
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}
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static int psci_cpu_init_idle(struct device *dev, struct cpuidle_driver *drv,
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unsigned int cpu, unsigned int state_count)
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{
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struct device_node *cpu_node;
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int ret;
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/*
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* If the PSCI cpu_suspend function hook has not been initialized
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* idle states must not be enabled, so bail out
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*/
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if (!psci_ops.cpu_suspend)
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return -EOPNOTSUPP;
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cpu_node = of_cpu_device_node_get(cpu);
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if (!cpu_node)
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return -ENODEV;
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ret = psci_dt_cpu_init_idle(dev, drv, cpu_node, state_count, cpu);
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of_node_put(cpu_node);
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return ret;
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}
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static void psci_cpu_deinit_idle(int cpu)
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{
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struct psci_cpuidle_data *data = per_cpu_ptr(&psci_cpuidle_data, cpu);
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psci_dt_detach_cpu(data->dev);
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psci_cpuidle_use_cpuhp = false;
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}
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static int psci_idle_init_cpu(struct device *dev, int cpu)
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{
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struct cpuidle_driver *drv;
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struct device_node *cpu_node;
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const char *enable_method;
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int ret = 0;
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cpu_node = of_cpu_device_node_get(cpu);
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if (!cpu_node)
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return -ENODEV;
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/*
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* Check whether the enable-method for the cpu is PSCI, fail
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* if it is not.
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*/
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enable_method = of_get_property(cpu_node, "enable-method", NULL);
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if (!enable_method || (strcmp(enable_method, "psci")))
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ret = -ENODEV;
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of_node_put(cpu_node);
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if (ret)
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return ret;
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drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
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if (!drv)
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return -ENOMEM;
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drv->name = "psci_idle";
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drv->owner = THIS_MODULE;
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drv->cpumask = (struct cpumask *)cpumask_of(cpu);
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/*
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* PSCI idle states relies on architectural WFI to be represented as
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* state index 0.
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*/
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drv->states[0].enter = psci_enter_idle_state;
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drv->states[0].exit_latency = 1;
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drv->states[0].target_residency = 1;
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drv->states[0].power_usage = UINT_MAX;
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strcpy(drv->states[0].name, "WFI");
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strcpy(drv->states[0].desc, "ARM WFI");
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/*
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* If no DT idle states are detected (ret == 0) let the driver
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* initialization fail accordingly since there is no reason to
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* initialize the idle driver if only wfi is supported, the
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* default archictectural back-end already executes wfi
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* on idle entry.
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*/
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ret = dt_init_idle_driver(drv, psci_idle_state_match, 1);
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if (ret <= 0)
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return ret ? : -ENODEV;
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/*
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* Initialize PSCI idle states.
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*/
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ret = psci_cpu_init_idle(dev, drv, cpu, ret);
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if (ret) {
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pr_err("CPU %d failed to PSCI idle\n", cpu);
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return ret;
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}
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ret = cpuidle_register(drv, NULL);
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if (ret)
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goto deinit;
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cpuidle_cooling_register(drv);
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return 0;
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deinit:
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psci_cpu_deinit_idle(cpu);
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return ret;
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}
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/*
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* psci_idle_probe - Initializes PSCI cpuidle driver
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*
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* Initializes PSCI cpuidle driver for all CPUs, if any CPU fails
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* to register cpuidle driver then rollback to cancel all CPUs
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* registration.
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*/
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static int psci_cpuidle_probe(struct platform_device *pdev)
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{
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int cpu, ret;
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struct cpuidle_driver *drv;
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struct cpuidle_device *dev;
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for_each_possible_cpu(cpu) {
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ret = psci_idle_init_cpu(&pdev->dev, cpu);
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if (ret)
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goto out_fail;
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}
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psci_idle_init_cpuhp();
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return 0;
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out_fail:
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while (--cpu >= 0) {
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dev = per_cpu(cpuidle_devices, cpu);
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drv = cpuidle_get_cpu_driver(dev);
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cpuidle_unregister(drv);
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psci_cpu_deinit_idle(cpu);
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}
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return ret;
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}
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static struct platform_driver psci_cpuidle_driver = {
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.probe = psci_cpuidle_probe,
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.driver = {
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.name = "psci-cpuidle",
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},
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};
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static int __init psci_idle_init(void)
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{
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struct platform_device *pdev;
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int ret;
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ret = platform_driver_register(&psci_cpuidle_driver);
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if (ret)
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return ret;
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pdev = platform_device_register_simple("psci-cpuidle", -1, NULL, 0);
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if (IS_ERR(pdev)) {
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platform_driver_unregister(&psci_cpuidle_driver);
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return PTR_ERR(pdev);
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}
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return 0;
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}
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device_initcall(psci_idle_init);
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