mirror of https://gitee.com/openkylin/linux.git
152 lines
3.3 KiB
C
152 lines
3.3 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/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/psci.h>
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#include <linux/slab.h>
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#include <asm/cpuidle.h>
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#include "dt_idle_states.h"
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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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return CPU_PM_CPU_IDLE_ENTER(psci_cpu_suspend_enter, idx);
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}
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static struct cpuidle_driver psci_idle_driver __initdata = {
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.name = "psci_idle",
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.owner = THIS_MODULE,
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/*
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* PSCI idle states relies on architectural WFI to
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* be represented as state index 0.
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*/
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.states[0] = {
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.enter = psci_enter_idle_state,
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.exit_latency = 1,
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.target_residency = 1,
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.power_usage = UINT_MAX,
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.name = "WFI",
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.desc = "ARM WFI",
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}
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};
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static const struct of_device_id psci_idle_state_match[] __initconst = {
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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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static int __init psci_idle_init_cpu(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 = kmemdup(&psci_idle_driver, sizeof(*drv), GFP_KERNEL);
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if (!drv)
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return -ENOMEM;
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drv->cpumask = (struct cpumask *)cpumask_of(cpu);
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/*
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* Initialize idle states data, starting at index 1, since
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* by default idle state 0 is the quiescent state reached
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* by the cpu by executing the wfi instruction.
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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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ret = ret ? : -ENODEV;
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goto out_kfree_drv;
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}
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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(cpu);
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if (ret) {
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pr_err("CPU %d failed to PSCI idle\n", cpu);
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goto out_kfree_drv;
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}
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ret = cpuidle_register(drv, NULL);
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if (ret)
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goto out_kfree_drv;
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return 0;
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out_kfree_drv:
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kfree(drv);
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return ret;
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}
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/*
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* psci_idle_init - 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 __init psci_idle_init(void)
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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(cpu);
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if (ret)
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goto out_fail;
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}
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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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kfree(drv);
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}
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return ret;
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}
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device_initcall(psci_idle_init);
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