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1// SPDX-License-Identifier: GPL-2.02/*3 * PM domains for CPUs via genpd - managed by cpuidle-psci.4 *5 * Copyright (C) 2019 Linaro Ltd.6 * Author: Ulf Hansson <ulf.hansson@linaro.org>7 *8 */9 10#define pr_fmt(fmt) "CPUidle PSCI: " fmt11 12#include <linux/cpu.h>13#include <linux/device.h>14#include <linux/kernel.h>15#include <linux/platform_device.h>16#include <linux/pm_domain.h>17#include <linux/pm_runtime.h>18#include <linux/psci.h>19#include <linux/slab.h>20#include <linux/string.h>21 22#include "cpuidle-psci.h"23#include "dt_idle_genpd.h"24 25struct psci_pd_provider {26 struct list_head link;27 struct device_node *node;28};29 30static LIST_HEAD(psci_pd_providers);31static bool psci_pd_allow_domain_state;32 33static int psci_pd_power_off(struct generic_pm_domain *pd)34{35 struct genpd_power_state *state = &pd->states[pd->state_idx];36 u32 *pd_state;37 38 if (!state->data)39 return 0;40 41 if (!psci_pd_allow_domain_state)42 return -EBUSY;43 44 /* OSI mode is enabled, set the corresponding domain state. */45 pd_state = state->data;46 psci_set_domain_state(*pd_state);47 48 return 0;49}50 51static int psci_pd_init(struct device_node *np, bool use_osi)52{53 struct generic_pm_domain *pd;54 struct psci_pd_provider *pd_provider;55 struct dev_power_governor *pd_gov;56 int ret = -ENOMEM;57 58 pd = dt_idle_pd_alloc(np, psci_dt_parse_state_node);59 if (!pd)60 goto out;61 62 pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);63 if (!pd_provider)64 goto free_pd;65 66 pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;67 68 /*69 * Allow power off when OSI has been successfully enabled.70 * On a PREEMPT_RT based configuration the domain idle states are71 * supported, but only during system-wide suspend.72 */73 if (use_osi) {74 pd->power_off = psci_pd_power_off;75 if (IS_ENABLED(CONFIG_PREEMPT_RT))76 pd->flags |= GENPD_FLAG_RPM_ALWAYS_ON;77 } else {78 pd->flags |= GENPD_FLAG_ALWAYS_ON;79 }80 81 /* Use governor for CPU PM domains if it has some states to manage. */82 pd_gov = pd->states ? &pm_domain_cpu_gov : NULL;83 84 ret = pm_genpd_init(pd, pd_gov, false);85 if (ret)86 goto free_pd_prov;87 88 ret = of_genpd_add_provider_simple(np, pd);89 if (ret)90 goto remove_pd;91 92 pd_provider->node = of_node_get(np);93 list_add(&pd_provider->link, &psci_pd_providers);94 95 pr_debug("init PM domain %s\n", pd->name);96 return 0;97 98remove_pd:99 pm_genpd_remove(pd);100free_pd_prov:101 kfree(pd_provider);102free_pd:103 dt_idle_pd_free(pd);104out:105 pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);106 return ret;107}108 109static void psci_pd_remove(void)110{111 struct psci_pd_provider *pd_provider, *it;112 struct generic_pm_domain *genpd;113 114 list_for_each_entry_safe_reverse(pd_provider, it,115 &psci_pd_providers, link) {116 of_genpd_del_provider(pd_provider->node);117 118 genpd = of_genpd_remove_last(pd_provider->node);119 if (!IS_ERR(genpd))120 kfree(genpd);121 122 of_node_put(pd_provider->node);123 list_del(&pd_provider->link);124 kfree(pd_provider);125 }126}127 128static void psci_cpuidle_domain_sync_state(struct device *dev)129{130 /*131 * All devices have now been attached/probed to the PM domain topology,132 * hence it's fine to allow domain states to be picked.133 */134 psci_pd_allow_domain_state = true;135}136 137static const struct of_device_id psci_of_match[] = {138 { .compatible = "arm,psci-1.0" },139 {}140};141 142static int psci_cpuidle_domain_probe(struct platform_device *pdev)143{144 struct device_node *np = pdev->dev.of_node;145 bool use_osi = psci_has_osi_support();146 int ret = 0, pd_count = 0;147 148 if (!np)149 return -ENODEV;150 151 /*152 * Parse child nodes for the "#power-domain-cells" property and153 * initialize a genpd/genpd-of-provider pair when it's found.154 */155 for_each_child_of_node_scoped(np, node) {156 if (!of_property_present(node, "#power-domain-cells"))157 continue;158 159 ret = psci_pd_init(node, use_osi);160 if (ret)161 goto exit;162 163 pd_count++;164 }165 166 /* Bail out if not using the hierarchical CPU topology. */167 if (!pd_count)168 return 0;169 170 /* Link genpd masters/subdomains to model the CPU topology. */171 ret = dt_idle_pd_init_topology(np);172 if (ret)173 goto remove_pd;174 175 /* let's try to enable OSI. */176 ret = psci_set_osi_mode(use_osi);177 if (ret)178 goto remove_pd;179 180 pr_info("Initialized CPU PM domain topology using %s mode\n",181 use_osi ? "OSI" : "PC");182 return 0;183 184remove_pd:185 dt_idle_pd_remove_topology(np);186 psci_pd_remove();187exit:188 pr_err("failed to create CPU PM domains ret=%d\n", ret);189 return ret;190}191 192static struct platform_driver psci_cpuidle_domain_driver = {193 .probe = psci_cpuidle_domain_probe,194 .driver = {195 .name = "psci-cpuidle-domain",196 .of_match_table = psci_of_match,197 .sync_state = psci_cpuidle_domain_sync_state,198 },199};200 201static int __init psci_idle_init_domains(void)202{203 return platform_driver_register(&psci_cpuidle_domain_driver);204}205core_initcall(psci_idle_init_domains);206