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// SPDX-License-Identifier: GPL-2.0-only
/*
* PSCI CPU idle driver.
*
* Copyright (C) 2019 ARM Ltd.
* Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
*/
#define pr_fmt(fmt) "CPUidle PSCI: " fmt
#include <linux/cpuidle.h>
#include <linux/cpumask.h>
#include <linux/cpu_pm.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/psci.h>
#include <linux/slab.h>
#include <asm/cpuidle.h>
#include "dt_idle_states.h"
static int psci_enter_idle_state(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int idx)
{
return CPU_PM_CPU_IDLE_ENTER(psci_cpu_suspend_enter, idx);
}
static struct cpuidle_driver psci_idle_driver __initdata = {
.name = "psci_idle",
.owner = THIS_MODULE,
/*
* PSCI idle states relies on architectural WFI to
* be represented as state index 0.
*/
.states[0] = {
.enter = psci_enter_idle_state,
.exit_latency = 1,
.target_residency = 1,
.power_usage = UINT_MAX,
.name = "WFI",
.desc = "ARM WFI",
}
};
static const struct of_device_id psci_idle_state_match[] __initconst = {
{ .compatible = "arm,idle-state",
.data = psci_enter_idle_state },
{ },
};
static int __init psci_idle_init_cpu(int cpu)
{
struct cpuidle_driver *drv;
struct device_node *cpu_node;
const char *enable_method;
int ret = 0;
cpu_node = of_cpu_device_node_get(cpu);
if (!cpu_node)
return -ENODEV;
/*
* Check whether the enable-method for the cpu is PSCI, fail
* if it is not.
*/
enable_method = of_get_property(cpu_node, "enable-method", NULL);
if (!enable_method || (strcmp(enable_method, "psci")))
ret = -ENODEV;
of_node_put(cpu_node);
if (ret)
return ret;
drv = kmemdup(&psci_idle_driver, sizeof(*drv), GFP_KERNEL);
if (!drv)
return -ENOMEM;
drv->cpumask = (struct cpumask *)cpumask_of(cpu);
/*
* Initialize idle states data, starting at index 1, since
* by default idle state 0 is the quiescent state reached
* by the cpu by executing the wfi instruction.
*
* If no DT idle states are detected (ret == 0) let the driver
* initialization fail accordingly since there is no reason to
* initialize the idle driver if only wfi is supported, the
* default archictectural back-end already executes wfi
* on idle entry.
*/
ret = dt_init_idle_driver(drv, psci_idle_state_match, 1);
if (ret <= 0) {
ret = ret ? : -ENODEV;
goto out_kfree_drv;
}
/*
* Initialize PSCI idle states.
*/
ret = psci_cpu_init_idle(cpu);
if (ret) {
pr_err("CPU %d failed to PSCI idle\n", cpu);
goto out_kfree_drv;
}
ret = cpuidle_register(drv, NULL);
if (ret)
goto out_kfree_drv;
return 0;
out_kfree_drv:
kfree(drv);
return ret;
}
/*
* psci_idle_init - Initializes PSCI cpuidle driver
*
* Initializes PSCI cpuidle driver for all CPUs, if any CPU fails
* to register cpuidle driver then rollback to cancel all CPUs
* registration.
*/
static int __init psci_idle_init(void)
{
int cpu, ret;
struct cpuidle_driver *drv;
struct cpuidle_device *dev;
for_each_possible_cpu(cpu) {
ret = psci_idle_init_cpu(cpu);
if (ret)
goto out_fail;
}
return 0;
out_fail:
while (--cpu >= 0) {
dev = per_cpu(cpuidle_devices, cpu);
drv = cpuidle_get_cpu_driver(dev);
cpuidle_unregister(drv);
kfree(drv);
}
return ret;
}
device_initcall(psci_idle_init);
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