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linux-next/drivers/cpuidle/cpuidle-psci-domain.c
Ulf Hansson 81f94ddfec cpuidle: psci: Prevent domain idlestates until consumers are ready
Depending on the SoC/platform, additional devices may be part of the PSCI
PM domain topology. This is the case with 'qcom,rpmh-rsc' device, for
example, even if this is not yet visible in the corresponding DTS-files.

Without going into too much details, a device like the 'qcom,rpmh-rsc' may
have HW constraints that needs to be obeyed to, before a domain idlestate
can be picked.

Therefore, let's implement the ->sync_state() callback to receive a
notification when all consumers of the PSCI PM domain providers have been
attached/probed to it. In this way, we can make sure all constraints from
all relevant devices, are taken into account before allowing a domain
idlestate to be picked.

Acked-by: Saravana Kannan <saravanak@google.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-07-29 18:38:30 +02:00

337 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)
{
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->power_off = psci_pd_power_off;
pd->states = states;
pd->state_count = state_count;
pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
/* 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, bool add)
{
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 = add ? of_genpd_add_subdomain(&parent, &child) :
of_genpd_remove_subdomain(&parent, &child);
of_node_put(parent.np);
if (ret) {
of_node_put(node);
return ret;
}
}
return 0;
}
static int psci_pd_add_topology(struct device_node *np)
{
return psci_pd_init_topology(np, true);
}
static void psci_pd_remove_topology(struct device_node *np)
{
psci_pd_init_topology(np, false);
}
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;
int ret = 0, pd_count = 0;
if (!np)
return -ENODEV;
/* Currently limit the hierarchical topology to be used in OSI mode. */
if (!psci_has_osi_support())
return 0;
/*
* 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);
if (ret)
goto put_node;
pd_count++;
}
/* Bail out if not using the hierarchical CPU topology. */
if (!pd_count)
return 0;
/* Link genpd masters/subdomains to model the CPU topology. */
ret = psci_pd_add_topology(np);
if (ret)
goto remove_pd;
/* Try to enable OSI mode. */
ret = psci_set_osi_mode();
if (ret) {
pr_warn("failed to enable OSI mode: %d\n", ret);
psci_pd_remove_topology(np);
goto remove_pd;
}
pr_info("Initialized CPU PM domain topology\n");
return 0;
put_node:
of_node_put(node);
remove_pd:
if (pd_count)
psci_pd_remove();
pr_err("failed to create CPU PM domains ret=%d\n", ret);
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);
return dev;
}
void psci_dt_detach_cpu(struct device *dev)
{
if (IS_ERR_OR_NULL(dev))
return;
dev_pm_domain_detach(dev, false);
}