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 pd->flags |= GENPD_FLAG_ACTIVE_WAKEUP; 76 if (IS_ENABLED(CONFIG_PREEMPT_RT)) 77 pd->flags |= GENPD_FLAG_RPM_ALWAYS_ON; 78 } else { 79 pd->flags |= GENPD_FLAG_ALWAYS_ON; 80 } 81 82 /* Use governor for CPU PM domains if it has some states to manage. */ 83 pd_gov = pd->states ? &pm_domain_cpu_gov : NULL; 84 85 ret = pm_genpd_init(pd, pd_gov, false); 86 if (ret) 87 goto free_pd_prov; 88 89 ret = of_genpd_add_provider_simple(np, pd); 90 if (ret) 91 goto remove_pd; 92 93 pd_provider->node = of_node_get(np); 94 list_add(&pd_provider->link, &psci_pd_providers); 95 96 pr_debug("init PM domain %s\n", pd->name); 97 return 0; 98 99 remove_pd: 100 pm_genpd_remove(pd); 101 free_pd_prov: 102 kfree(pd_provider); 103 free_pd: 104 dt_idle_pd_free(pd); 105 out: 106 pr_err("failed to init PM domain ret=%d %pOF\n", ret, np); 107 return ret; 108 } 109 110 static void psci_pd_remove(void) 111 { 112 struct psci_pd_provider *pd_provider, *it; 113 struct generic_pm_domain *genpd; 114 115 list_for_each_entry_safe_reverse(pd_provider, it, 116 &psci_pd_providers, link) { 117 of_genpd_del_provider(pd_provider->node); 118 119 genpd = of_genpd_remove_last(pd_provider->node); 120 if (!IS_ERR(genpd)) 121 kfree(genpd); 122 123 of_node_put(pd_provider->node); 124 list_del(&pd_provider->link); 125 kfree(pd_provider); 126 } 127 } 128 129 static void psci_cpuidle_domain_sync_state(struct device *dev) 130 { 131 /* 132 * All devices have now been attached/probed to the PM domain topology, 133 * hence it's fine to allow domain states to be picked. 134 */ 135 psci_pd_allow_domain_state = true; 136 } 137 138 static const struct of_device_id psci_of_match[] = { 139 { .compatible = "arm,psci-1.0" }, 140 {} 141 }; 142 143 static int psci_cpuidle_domain_probe(struct platform_device *pdev) 144 { 145 struct device_node *np = pdev->dev.of_node; 146 bool use_osi = psci_has_osi_support(); 147 int ret = 0, pd_count = 0; 148 149 if (!np) 150 return -ENODEV; 151 152 /* 153 * Parse child nodes for the "#power-domain-cells" property and 154 * initialize a genpd/genpd-of-provider pair when it's found. 155 */ 156 for_each_child_of_node_scoped(np, node) { 157 if (!of_property_present(node, "#power-domain-cells")) 158 continue; 159 160 ret = psci_pd_init(node, use_osi); 161 if (ret) 162 goto exit; 163 164 pd_count++; 165 } 166 167 /* Bail out if not using the hierarchical CPU topology. */ 168 if (!pd_count) 169 return 0; 170 171 /* Link genpd masters/subdomains to model the CPU topology. */ 172 ret = dt_idle_pd_init_topology(np); 173 if (ret) 174 goto remove_pd; 175 176 /* let's try to enable OSI. */ 177 ret = psci_set_osi_mode(use_osi); 178 if (ret) 179 goto remove_pd; 180 181 pr_info("Initialized CPU PM domain topology using %s mode\n", 182 use_osi ? "OSI" : "PC"); 183 return 0; 184 185 remove_pd: 186 dt_idle_pd_remove_topology(np); 187 psci_pd_remove(); 188 exit: 189 pr_err("failed to create CPU PM domains ret=%d\n", ret); 190 return ret; 191 } 192 193 static struct platform_driver psci_cpuidle_domain_driver = { 194 .probe = psci_cpuidle_domain_probe, 195 .driver = { 196 .name = "psci-cpuidle-domain", 197 .of_match_table = psci_of_match, 198 .sync_state = psci_cpuidle_domain_sync_state, 199 }, 200 }; 201 202 static int __init psci_idle_init_domains(void) 203 { 204 return platform_driver_register(&psci_cpuidle_domain_driver); 205 } 206 core_initcall(psci_idle_init_domains); 207