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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_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);
- }
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