linux-stable/drivers/cpuidle/cpuidle-psci-domain.c
Ulf Hansson 670c90def0 cpuidle: psci: Enable suspend-to-idle for PSCI OSI mode
To select domain idlestates for cpuidle-psci when OSI mode has been
enabled, the PM domains via genpd are being managed through runtime PM.
This works fine for the regular idlepath, but it doesn't during system wide
suspend. More precisely, the domain idlestates becomes temporarily
disabled, which is because the PM core disables runtime PM for devices
during system wide suspend.

Later in the system suspend phase, genpd intends to deal with this from its
->suspend_noirq() callback, but this doesn't work as expected for a device
corresponding to a CPU, because the domain idlestates needs to be selected
on a per CPU basis (the PM core doesn't invoke the callbacks like that).

To address this problem, let's enable the syscore flag for the
corresponding CPU device that becomes successfully attached to its PM
domain (applicable only in OSI mode). This informs the PM core to skip
invoke the system wide suspend/resume callbacks for the device, thus also
prevents genpd from screwing up its internal state of it.

Moreover, to properly select a domain idlestate for the CPUs during
suspend-to-idle, let's assign a specific ->enter_s2idle() callback for the
corresponding domain idlestate (applicable only in OSI mode). From that
callback, let's invoke dev_pm_genpd_suspend|resume(), as this allows a
domain idlestate to be selected for the current CPU by genpd.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-11-10 20:42:01 +01:00

341 lines
7.1 KiB
C

// 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_parse_state_nodes(struct genpd_power_state *states,
int state_count)
{
int i, ret;
u32 psci_state, *psci_state_buf;
for (i = 0; i < state_count; i++) {
ret = psci_dt_parse_state_node(to_of_node(states[i].fwnode),
&psci_state);
if (ret)
goto free_state;
psci_state_buf = kmalloc(sizeof(u32), GFP_KERNEL);
if (!psci_state_buf) {
ret = -ENOMEM;
goto free_state;
}
*psci_state_buf = psci_state;
states[i].data = psci_state_buf;
}
return 0;
free_state:
i--;
for (; i >= 0; i--)
kfree(states[i].data);
return ret;
}
static int psci_pd_parse_states(struct device_node *np,
struct genpd_power_state **states, int *state_count)
{
int ret;
/* Parse the domain idle states. */
ret = of_genpd_parse_idle_states(np, states, state_count);
if (ret)
return ret;
/* Fill out the PSCI specifics for each found state. */
ret = psci_pd_parse_state_nodes(*states, *state_count);
if (ret)
kfree(*states);
return ret;
}
static void psci_pd_free_states(struct genpd_power_state *states,
unsigned int state_count)
{
int i;
for (i = 0; i < state_count; i++)
kfree(states[i].data);
kfree(states);
}
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;
struct genpd_power_state *states = NULL;
int ret = -ENOMEM, state_count = 0;
pd = kzalloc(sizeof(*pd), GFP_KERNEL);
if (!pd)
goto out;
pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
if (!pd_provider)
goto free_pd;
pd->name = kasprintf(GFP_KERNEL, "%pOF", np);
if (!pd->name)
goto free_pd_prov;
/*
* Parse the domain idle states and let genpd manage the state selection
* for those being compatible with "domain-idle-state".
*/
ret = psci_pd_parse_states(np, &states, &state_count);
if (ret)
goto free_name;
pd->free_states = psci_pd_free_states;
pd->name = kbasename(pd->name);
pd->states = states;
pd->state_count = state_count;
pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
/* Allow power off when OSI has been successfully enabled. */
if (use_osi)
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 = state_count > 0 ? &pm_domain_cpu_gov : NULL;
ret = pm_genpd_init(pd, pd_gov, false);
if (ret) {
psci_pd_free_states(states, state_count);
goto free_name;
}
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_name:
kfree(pd->name);
free_pd_prov:
kfree(pd_provider);
free_pd:
kfree(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 int psci_pd_init_topology(struct device_node *np)
{
struct device_node *node;
struct of_phandle_args child, parent;
int ret;
for_each_child_of_node(np, node) {
if (of_parse_phandle_with_args(node, "power-domains",
"#power-domain-cells", 0, &parent))
continue;
child.np = node;
child.args_count = 0;
ret = of_genpd_add_subdomain(&parent, &child);
of_node_put(parent.np);
if (ret) {
of_node_put(node);
return ret;
}
}
return 0;
}
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) {
pr_warn("failed to enable OSI mode: %d\n", 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 = psci_pd_init_topology(np);
if (ret)
goto remove_pd;
pr_info("Initialized CPU PM domain topology\n");
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);
struct device *psci_dt_attach_cpu(int cpu)
{
struct device *dev;
dev = dev_pm_domain_attach_by_name(get_cpu_device(cpu), "psci");
if (IS_ERR_OR_NULL(dev))
return dev;
pm_runtime_irq_safe(dev);
if (cpu_online(cpu))
pm_runtime_get_sync(dev);
dev_pm_syscore_device(dev, true);
return dev;
}
void psci_dt_detach_cpu(struct device *dev)
{
if (IS_ERR_OR_NULL(dev))
return;
dev_pm_domain_detach(dev, false);
}