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// SPDX-License-Identifier: GPL-2.0
/*
* PM domains for CPUs via genpd - managed by cpuidle-psci.
*
* Copyright (C) 2019 Linaro Ltd.
* Author: Ulf Hansson <ulf.hansson@linaro.org>
*
*/
#define pr_fmt(fmt) "CPUidle PSCI: " fmt
#include <linux/cpu.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#include <linux/psci.h>
#include <linux/slab.h>
#include <linux/string.h>
#include "cpuidle-psci.h"
struct psci_pd_provider {
struct list_head link;
struct device_node *node;
};
static LIST_HEAD(psci_pd_providers);
static bool psci_pd_allow_domain_state;
static int psci_pd_power_off(struct generic_pm_domain *pd)
{
struct genpd_power_state *state = &pd->states[pd->state_idx];
u32 *pd_state;
if (!state->data)
return 0;
if (!psci_pd_allow_domain_state)
return -EBUSY;
/* OSI mode is enabled, set the corresponding domain state. */
pd_state = state->data;
psci_set_domain_state(*pd_state);
return 0;
}
static int psci_pd_init(struct device_node *np, bool use_osi)
{
struct generic_pm_domain *pd;
struct psci_pd_provider *pd_provider;
struct dev_power_governor *pd_gov;
int ret = -ENOMEM;
pd = dt_idle_pd_alloc(np, psci_dt_parse_state_node);
if (!pd)
goto out;
pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
if (!pd_provider)
goto free_pd;
pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
/*
* Allow power off when OSI has been successfully enabled.
* PREEMPT_RT is not yet ready to enter domain idle states.
*/
if (use_osi && !IS_ENABLED(CONFIG_PREEMPT_RT))
pd->power_off = psci_pd_power_off;
else
pd->flags |= GENPD_FLAG_ALWAYS_ON;
/* Use governor for CPU PM domains if it has some states to manage. */
pd_gov = pd->states ? &pm_domain_cpu_gov : NULL;
ret = pm_genpd_init(pd, pd_gov, false);
if (ret)
goto free_pd_prov;
ret = of_genpd_add_provider_simple(np, pd);
if (ret)
goto remove_pd;
pd_provider->node = of_node_get(np);
list_add(&pd_provider->link, &psci_pd_providers);
pr_debug("init PM domain %s\n", pd->name);
return 0;
remove_pd:
pm_genpd_remove(pd);
free_pd_prov:
kfree(pd_provider);
free_pd:
dt_idle_pd_free(pd);
out:
pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
return ret;
}
static void psci_pd_remove(void)
{
struct psci_pd_provider *pd_provider, *it;
struct generic_pm_domain *genpd;
list_for_each_entry_safe(pd_provider, it, &psci_pd_providers, link) {
of_genpd_del_provider(pd_provider->node);
genpd = of_genpd_remove_last(pd_provider->node);
if (!IS_ERR(genpd))
kfree(genpd);
of_node_put(pd_provider->node);
list_del(&pd_provider->link);
kfree(pd_provider);
}
}
static bool psci_pd_try_set_osi_mode(void)
{
int ret;
if (!psci_has_osi_support())
return false;
ret = psci_set_osi_mode(true);
if (ret)
return false;
return true;
}
static void psci_cpuidle_domain_sync_state(struct device *dev)
{
/*
* All devices have now been attached/probed to the PM domain topology,
* hence it's fine to allow domain states to be picked.
*/
psci_pd_allow_domain_state = true;
}
static const struct of_device_id psci_of_match[] = {
{ .compatible = "arm,psci-1.0" },
{}
};
static int psci_cpuidle_domain_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct device_node *node;
bool use_osi;
int ret = 0, pd_count = 0;
if (!np)
return -ENODEV;
/* If OSI mode is supported, let's try to enable it. */
use_osi = psci_pd_try_set_osi_mode();
/*
* Parse child nodes for the "#power-domain-cells" property and
* initialize a genpd/genpd-of-provider pair when it's found.
*/
for_each_child_of_node(np, node) {
if (!of_find_property(node, "#power-domain-cells", NULL))
continue;
ret = psci_pd_init(node, use_osi);
if (ret)
goto put_node;
pd_count++;
}
/* Bail out if not using the hierarchical CPU topology. */
if (!pd_count)
goto no_pd;
/* Link genpd masters/subdomains to model the CPU topology. */
ret = dt_idle_pd_init_topology(np);
if (ret)
goto remove_pd;
pr_info("Initialized CPU PM domain topology using %s mode\n",
use_osi ? "OSI" : "PC");
return 0;
put_node:
of_node_put(node);
remove_pd:
psci_pd_remove();
pr_err("failed to create CPU PM domains ret=%d\n", ret);
no_pd:
if (use_osi)
psci_set_osi_mode(false);
return ret;
}
static struct platform_driver psci_cpuidle_domain_driver = {
.probe = psci_cpuidle_domain_probe,
.driver = {
.name = "psci-cpuidle-domain",
.of_match_table = psci_of_match,
.sync_state = psci_cpuidle_domain_sync_state,
},
};
static int __init psci_idle_init_domains(void)
{
return platform_driver_register(&psci_cpuidle_domain_driver);
}
subsys_initcall(psci_idle_init_domains);
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