// SPDX-License-Identifier: GPL-2.0-only
/*
* RISC-V SBI CPU idle driver.
*
* Copyright (c) 2021 Western Digital Corporation or its affiliates.
* Copyright (c) 2022 Ventana Micro Systems Inc.
*/
#define pr_fmt(fmt) "cpuidle-riscv-sbi: " fmt
#include <linux/cpuhotplug.h>
#include <linux/cpuidle.h>
#include <linux/cpumask.h>
#include <linux/cpu_pm.h>
#include <linux/cpu_cooling.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#include <asm/cpuidle.h>
#include <asm/sbi.h>
#include <asm/smp.h>
#include <asm/suspend.h>
#include "dt_idle_states.h"
#include "dt_idle_genpd.h"
struct sbi_cpuidle_data {
u32 *states;
struct device *dev;
};
struct sbi_domain_state {
bool available;
u32 state;
};
static DEFINE_PER_CPU_READ_MOSTLY(struct sbi_cpuidle_data, sbi_cpuidle_data);
static DEFINE_PER_CPU(struct sbi_domain_state, domain_state);
static bool sbi_cpuidle_use_osi;
static bool sbi_cpuidle_use_cpuhp;
static bool sbi_cpuidle_pd_allow_domain_state;
static inline void sbi_set_domain_state(u32 state)
{
struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
data->available = true;
data->state = state;
}
static inline u32 sbi_get_domain_state(void)
{
struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
return data->state;
}
static inline void sbi_clear_domain_state(void)
{
struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
data->available = false;
}
static inline bool sbi_is_domain_state_available(void)
{
struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
return data->available;
}
static __cpuidle int sbi_cpuidle_enter_state(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int idx)
{
u32 *states = __this_cpu_read(sbi_cpuidle_data.states);
u32 state = states[idx];
if (state & SBI_HSM_SUSP_NON_RET_BIT)
return CPU_PM_CPU_IDLE_ENTER_PARAM(riscv_sbi_hart_suspend, idx, state);
else
return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(riscv_sbi_hart_suspend,
idx, state);
}
static __cpuidle int __sbi_enter_domain_idle_state(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int idx,
bool s2idle)
{
struct sbi_cpuidle_data *data = this_cpu_ptr(&sbi_cpuidle_data);
u32 *states = data->states;
struct device *pd_dev = data->dev;
u32 state;
int ret;
ret = cpu_pm_enter();
if (ret)
return -1;
/* Do runtime PM to manage a hierarchical CPU toplogy. */
if (s2idle)
dev_pm_genpd_suspend(pd_dev);
else
pm_runtime_put_sync_suspend(pd_dev);
ct_cpuidle_enter();
if (sbi_is_domain_state_available())
state = sbi_get_domain_state();
else
state = states[idx];
ret = riscv_sbi_hart_suspend(state) ? -1 : idx;
ct_cpuidle_exit();
if (s2idle)
dev_pm_genpd_resume(pd_dev);
else
pm_runtime_get_sync(pd_dev);
cpu_pm_exit();
/* Clear the domain state to start fresh when back from idle. */
sbi_clear_domain_state();
return ret;
}
static int sbi_enter_domain_idle_state(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int idx)
{
return __sbi_enter_domain_idle_state(dev, drv, idx, false);
}
static int sbi_enter_s2idle_domain_idle_state(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int idx)
{
return __sbi_enter_domain_idle_state(dev, drv, idx, true);
}
static int sbi_cpuidle_cpuhp_up(unsigned int cpu)
{
struct device *pd_dev = __this_cpu_read(sbi_cpuidle_data.dev);
if (pd_dev)
pm_runtime_get_sync(pd_dev);
return 0;
}
static int sbi_cpuidle_cpuhp_down(unsigned int cpu)
{
struct device *pd_dev = __this_cpu_read(sbi_cpuidle_data.dev);
if (pd_dev) {
pm_runtime_put_sync(pd_dev);
/* Clear domain state to start fresh at next online. */
sbi_clear_domain_state();
}
return 0;
}
static void sbi_idle_init_cpuhp(void)
{
int err;
if (!sbi_cpuidle_use_cpuhp)
return;
err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING,
"cpuidle/sbi:online",
sbi_cpuidle_cpuhp_up,
sbi_cpuidle_cpuhp_down);
if (err)
pr_warn("Failed %d while setup cpuhp state\n", err);
}
static const struct of_device_id sbi_cpuidle_state_match[] = {
{ .compatible = "riscv,idle-state",
.data = sbi_cpuidle_enter_state },
{ },
};
static int sbi_dt_parse_state_node(struct device_node *np, u32 *state)
{
int err = of_property_read_u32(np, "riscv,sbi-suspend-param", state);
if (err) {
pr_warn("%pOF missing riscv,sbi-suspend-param property\n", np);
return err;
}
if (!riscv_sbi_suspend_state_is_valid(*state)) {
pr_warn("Invalid SBI suspend state %#x\n", *state);
return -EINVAL;
}
return 0;
}
static int sbi_dt_cpu_init_topology(struct cpuidle_driver *drv,
struct sbi_cpuidle_data *data,
unsigned int state_count, int cpu)
{
/* Currently limit the hierarchical topology to be used in OSI mode. */
if (!sbi_cpuidle_use_osi)
return 0;
data->dev = dt_idle_attach_cpu(cpu, "sbi");
if (IS_ERR_OR_NULL(data->dev))
return PTR_ERR_OR_ZERO(data->dev);
/*
* Using the deepest state for the CPU to trigger a potential selection
* of a shared state for the domain, assumes the domain states are all
* deeper states.
*/
drv->states[state_count - 1].flags |= CPUIDLE_FLAG_RCU_IDLE;
drv->states[state_count - 1].enter = sbi_enter_domain_idle_state;
drv->states[state_count - 1].enter_s2idle =
sbi_enter_s2idle_domain_idle_state;
sbi_cpuidle_use_cpuhp = true;
return 0;
}
static int sbi_cpuidle_dt_init_states(struct device *dev,
struct cpuidle_driver *drv,
unsigned int cpu,
unsigned int state_count)
{
struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
struct device_node *state_node;
struct device_node *cpu_node;
u32 *states;
int i, ret;
cpu_node = of_cpu_device_node_get(cpu);
if (!cpu_node)
return -ENODEV;
states = devm_kcalloc(dev, state_count, sizeof(*states), GFP_KERNEL);
if (!states) {
ret = -ENOMEM;
goto fail;
}
/* Parse SBI specific details from state DT nodes */
for (i = 1; i < state_count; i++) {
state_node = of_get_cpu_state_node(cpu_node, i - 1);
if (!state_node)
break;
ret = sbi_dt_parse_state_node(state_node, &states[i]);
of_node_put(state_node);
if (ret)
return ret;
pr_debug("sbi-state %#x index %d\n", states[i], i);
}
if (i != state_count) {
ret = -ENODEV;
goto fail;
}
/* Initialize optional data, used for the hierarchical topology. */
ret = sbi_dt_cpu_init_topology(drv, data, state_count, cpu);
if (ret < 0)
return ret;
/* Store states in the per-cpu struct. */
data->states = states;
fail:
of_node_put(cpu_node);
return ret;
}
static void sbi_cpuidle_deinit_cpu(int cpu)
{
struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
dt_idle_detach_cpu(data->dev);
sbi_cpuidle_use_cpuhp = false;
}
static int sbi_cpuidle_init_cpu(struct device *dev, int cpu)
{
struct cpuidle_driver *drv;
unsigned int state_count = 0;
int ret = 0;
drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
if (!drv)
return -ENOMEM;
drv->name = "sbi_cpuidle";
drv->owner = THIS_MODULE;
drv->cpumask = (struct cpumask *)cpumask_of(cpu);
/* RISC-V architectural WFI to be represented as state index 0. */
drv->states[0].enter = sbi_cpuidle_enter_state;
drv->states[0].exit_latency = 1;
drv->states[0].target_residency = 1;
drv->states[0].power_usage = UINT_MAX;
strcpy(drv->states[0].name, "WFI");
strcpy(drv->states[0].desc, "RISC-V WFI");
/*
* 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, sbi_cpuidle_state_match, 1);
if (ret <= 0) {
pr_debug("HART%ld: failed to parse DT idle states\n",
cpuid_to_hartid_map(cpu));
return ret ? : -ENODEV;
}
state_count = ret + 1; /* Include WFI state as well */
/* Initialize idle states from DT. */
ret = sbi_cpuidle_dt_init_states(dev, drv, cpu, state_count);
if (ret) {
pr_err("HART%ld: failed to init idle states\n",
cpuid_to_hartid_map(cpu));
return ret;
}
ret = cpuidle_register(drv, NULL);
if (ret)
goto deinit;
cpuidle_cooling_register(drv);
return 0;
deinit:
sbi_cpuidle_deinit_cpu(cpu);
return ret;
}
static void sbi_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.
*/
sbi_cpuidle_pd_allow_domain_state = true;
}
#ifdef CONFIG_DT_IDLE_GENPD
static int sbi_cpuidle_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 (!sbi_cpuidle_pd_allow_domain_state)
return -EBUSY;
/* OSI mode is enabled, set the corresponding domain state. */
pd_state = state->data;
sbi_set_domain_state(*pd_state);
return 0;
}
struct sbi_pd_provider {
struct list_head link;
struct device_node *node;
};
static LIST_HEAD(sbi_pd_providers);
static int sbi_pd_init(struct device_node *np)
{
struct generic_pm_domain *pd;
struct sbi_pd_provider *pd_provider;
struct dev_power_governor *pd_gov;
int ret = -ENOMEM;
pd = dt_idle_pd_alloc(np, sbi_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 is available. */
if (sbi_cpuidle_use_osi)
pd->power_off = sbi_cpuidle_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, &sbi_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 sbi_pd_remove(void)
{
struct sbi_pd_provider *pd_provider, *it;
struct generic_pm_domain *genpd;
list_for_each_entry_safe(pd_provider, it, &sbi_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 sbi_genpd_probe(struct device_node *np)
{
struct device_node *node;
int ret = 0, pd_count = 0;
if (!np)
return -ENODEV;
/*
* 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_property_present(node, "#power-domain-cells"))
continue;
ret = sbi_pd_init(node);
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;
return 0;
put_node:
of_node_put(node);
remove_pd:
sbi_pd_remove();
pr_err("failed to create CPU PM domains ret=%d\n", ret);
no_pd:
return ret;
}
#else
static inline int sbi_genpd_probe(struct device_node *np)
{
return 0;
}
#endif
static int sbi_cpuidle_probe(struct platform_device *pdev)
{
int cpu, ret;
struct cpuidle_driver *drv;
struct cpuidle_device *dev;
struct device_node *np, *pds_node;
/* Detect OSI support based on CPU DT nodes */
sbi_cpuidle_use_osi = true;
for_each_possible_cpu(cpu) {
np = of_cpu_device_node_get(cpu);
if (np &&
of_property_present(np, "power-domains") &&
of_property_present(np, "power-domain-names")) {
continue;
} else {
sbi_cpuidle_use_osi = false;
break;
}
}
/* Populate generic power domains from DT nodes */
pds_node = of_find_node_by_path("/cpus/power-domains");
if (pds_node) {
ret = sbi_genpd_probe(pds_node);
of_node_put(pds_node);
if (ret)
return ret;
}
/* Initialize CPU idle driver for each CPU */
for_each_possible_cpu(cpu) {
ret = sbi_cpuidle_init_cpu(&pdev->dev, cpu);
if (ret) {
pr_debug("HART%ld: idle driver init failed\n",
cpuid_to_hartid_map(cpu));
goto out_fail;
}
}
/* Setup CPU hotplut notifiers */
sbi_idle_init_cpuhp();
pr_info("idle driver registered for all CPUs\n");
return 0;
out_fail:
while (--cpu >= 0) {
dev = per_cpu(cpuidle_devices, cpu);
drv = cpuidle_get_cpu_driver(dev);
cpuidle_unregister(drv);
sbi_cpuidle_deinit_cpu(cpu);
}
return ret;
}
static struct platform_driver sbi_cpuidle_driver = {
.probe = sbi_cpuidle_probe,
.driver = {
.name = "sbi-cpuidle",
.sync_state = sbi_cpuidle_domain_sync_state,
},
};
static int __init sbi_cpuidle_init(void)
{
int ret;
struct platform_device *pdev;
if (!riscv_sbi_hsm_is_supported())
return 0;
ret = platform_driver_register(&sbi_cpuidle_driver);
if (ret)
return ret;
pdev = platform_device_register_simple("sbi-cpuidle",
-1, NULL, 0);
if (IS_ERR(pdev)) {
platform_driver_unregister(&sbi_cpuidle_driver);
return PTR_ERR(pdev);
}
return 0;
}
device_initcall(sbi_cpuidle_init);
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