1 // SPDX-License-Identifier: GPL-2.0 2 /* 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: " fmt 11 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 25 struct psci_pd_provider { 26 struct list_head link; 27 struct device_node *node; 28 }; 29 30 static LIST_HEAD(psci_pd_providers); 31 static bool psci_pd_allow_domain_state; 32 33 static 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 51 static 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 are 71 * 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 98 remove_pd: 99 pm_genpd_remove(pd); 100 free_pd_prov: 101 kfree(pd_provider); 102 free_pd: 103 dt_idle_pd_free(pd); 104 out: 105 pr_err("failed to init PM domain ret=%d %pOF\n", ret, np); 106 return ret; 107 } 108 109 static 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 } 127 128 static 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 } 136 137 static const struct of_device_id psci_of_match[] = { 138 { .compatible = "arm,psci-1.0" }, 139 {} 140 }; 141 142 static 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 and 153 * 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; 183 184 remove_pd: 185 dt_idle_pd_remove_topology(np); 186 psci_pd_remove(); 187 exit: 188 pr_err("failed to create CPU PM domains ret=%d\n", ret); 189 return ret; 190 } 191 192 static 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 }; 200 201 static int __init psci_idle_init_domains(void) 202 { 203 return platform_driver_register(&psci_cpuidle_domain_driver); 204 } 205 core_initcall(psci_idle_init_domains); 206