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 24 struct psci_pd_provider { 25 struct list_head link; 26 struct device_node *node; 27 }; 28 29 static LIST_HEAD(psci_pd_providers); 30 static bool psci_pd_allow_domain_state; 31 32 static int psci_pd_power_off(struct generic_pm_domain *pd) 33 { 34 struct genpd_power_state *state = &pd->states[pd->state_idx]; 35 u32 *pd_state; 36 37 if (!state->data) 38 return 0; 39 40 if (!psci_pd_allow_domain_state) 41 return -EBUSY; 42 43 /* OSI mode is enabled, set the corresponding domain state. */ 44 pd_state = state->data; 45 psci_set_domain_state(*pd_state); 46 47 return 0; 48 } 49 50 static int psci_pd_init(struct device_node *np, bool use_osi) 51 { 52 struct generic_pm_domain *pd; 53 struct psci_pd_provider *pd_provider; 54 struct dev_power_governor *pd_gov; 55 int ret = -ENOMEM; 56 57 pd = dt_idle_pd_alloc(np, psci_dt_parse_state_node); 58 if (!pd) 59 goto out; 60 61 pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL); 62 if (!pd_provider) 63 goto free_pd; 64 65 pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN; 66 67 /* 68 * Allow power off when OSI has been successfully enabled. 69 * PREEMPT_RT is not yet ready to enter domain idle states. 70 */ 71 if (use_osi && !IS_ENABLED(CONFIG_PREEMPT_RT)) 72 pd->power_off = psci_pd_power_off; 73 else 74 pd->flags |= GENPD_FLAG_ALWAYS_ON; 75 76 /* Use governor for CPU PM domains if it has some states to manage. */ 77 pd_gov = pd->states ? &pm_domain_cpu_gov : NULL; 78 79 ret = pm_genpd_init(pd, pd_gov, false); 80 if (ret) 81 goto free_pd_prov; 82 83 ret = of_genpd_add_provider_simple(np, pd); 84 if (ret) 85 goto remove_pd; 86 87 pd_provider->node = of_node_get(np); 88 list_add(&pd_provider->link, &psci_pd_providers); 89 90 pr_debug("init PM domain %s\n", pd->name); 91 return 0; 92 93 remove_pd: 94 pm_genpd_remove(pd); 95 free_pd_prov: 96 kfree(pd_provider); 97 free_pd: 98 dt_idle_pd_free(pd); 99 out: 100 pr_err("failed to init PM domain ret=%d %pOF\n", ret, np); 101 return ret; 102 } 103 104 static void psci_pd_remove(void) 105 { 106 struct psci_pd_provider *pd_provider, *it; 107 struct generic_pm_domain *genpd; 108 109 list_for_each_entry_safe(pd_provider, it, &psci_pd_providers, link) { 110 of_genpd_del_provider(pd_provider->node); 111 112 genpd = of_genpd_remove_last(pd_provider->node); 113 if (!IS_ERR(genpd)) 114 kfree(genpd); 115 116 of_node_put(pd_provider->node); 117 list_del(&pd_provider->link); 118 kfree(pd_provider); 119 } 120 } 121 122 static bool psci_pd_try_set_osi_mode(void) 123 { 124 int ret; 125 126 if (!psci_has_osi_support()) 127 return false; 128 129 ret = psci_set_osi_mode(true); 130 if (ret) 131 return false; 132 133 return true; 134 } 135 136 static void psci_cpuidle_domain_sync_state(struct device *dev) 137 { 138 /* 139 * All devices have now been attached/probed to the PM domain topology, 140 * hence it's fine to allow domain states to be picked. 141 */ 142 psci_pd_allow_domain_state = true; 143 } 144 145 static const struct of_device_id psci_of_match[] = { 146 { .compatible = "arm,psci-1.0" }, 147 {} 148 }; 149 150 static int psci_cpuidle_domain_probe(struct platform_device *pdev) 151 { 152 struct device_node *np = pdev->dev.of_node; 153 struct device_node *node; 154 bool use_osi; 155 int ret = 0, pd_count = 0; 156 157 if (!np) 158 return -ENODEV; 159 160 /* If OSI mode is supported, let's try to enable it. */ 161 use_osi = psci_pd_try_set_osi_mode(); 162 163 /* 164 * Parse child nodes for the "#power-domain-cells" property and 165 * initialize a genpd/genpd-of-provider pair when it's found. 166 */ 167 for_each_child_of_node(np, node) { 168 if (!of_find_property(node, "#power-domain-cells", NULL)) 169 continue; 170 171 ret = psci_pd_init(node, use_osi); 172 if (ret) 173 goto put_node; 174 175 pd_count++; 176 } 177 178 /* Bail out if not using the hierarchical CPU topology. */ 179 if (!pd_count) 180 goto no_pd; 181 182 /* Link genpd masters/subdomains to model the CPU topology. */ 183 ret = dt_idle_pd_init_topology(np); 184 if (ret) 185 goto remove_pd; 186 187 pr_info("Initialized CPU PM domain topology using %s mode\n", 188 use_osi ? "OSI" : "PC"); 189 return 0; 190 191 put_node: 192 of_node_put(node); 193 remove_pd: 194 psci_pd_remove(); 195 pr_err("failed to create CPU PM domains ret=%d\n", ret); 196 no_pd: 197 if (use_osi) 198 psci_set_osi_mode(false); 199 return ret; 200 } 201 202 static struct platform_driver psci_cpuidle_domain_driver = { 203 .probe = psci_cpuidle_domain_probe, 204 .driver = { 205 .name = "psci-cpuidle-domain", 206 .of_match_table = psci_of_match, 207 .sync_state = psci_cpuidle_domain_sync_state, 208 }, 209 }; 210 211 static int __init psci_idle_init_domains(void) 212 { 213 return platform_driver_register(&psci_cpuidle_domain_driver); 214 } 215 subsys_initcall(psci_idle_init_domains); 216