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 * PREEMPT_RT is not yet ready to enter domain idle states. 71 */ 72 if (use_osi && !IS_ENABLED(CONFIG_PREEMPT_RT)) 73 pd->power_off = psci_pd_power_off; 74 else 75 pd->flags |= GENPD_FLAG_ALWAYS_ON; 76 77 /* Use governor for CPU PM domains if it has some states to manage. */ 78 pd_gov = pd->states ? &pm_domain_cpu_gov : NULL; 79 80 ret = pm_genpd_init(pd, pd_gov, false); 81 if (ret) 82 goto free_pd_prov; 83 84 ret = of_genpd_add_provider_simple(np, pd); 85 if (ret) 86 goto remove_pd; 87 88 pd_provider->node = of_node_get(np); 89 list_add(&pd_provider->link, &psci_pd_providers); 90 91 pr_debug("init PM domain %s\n", pd->name); 92 return 0; 93 94 remove_pd: 95 pm_genpd_remove(pd); 96 free_pd_prov: 97 kfree(pd_provider); 98 free_pd: 99 dt_idle_pd_free(pd); 100 out: 101 pr_err("failed to init PM domain ret=%d %pOF\n", ret, np); 102 return ret; 103 } 104 105 static void psci_pd_remove(void) 106 { 107 struct psci_pd_provider *pd_provider, *it; 108 struct generic_pm_domain *genpd; 109 110 list_for_each_entry_safe_reverse(pd_provider, it, 111 &psci_pd_providers, link) { 112 of_genpd_del_provider(pd_provider->node); 113 114 genpd = of_genpd_remove_last(pd_provider->node); 115 if (!IS_ERR(genpd)) 116 kfree(genpd); 117 118 of_node_put(pd_provider->node); 119 list_del(&pd_provider->link); 120 kfree(pd_provider); 121 } 122 } 123 124 static void psci_cpuidle_domain_sync_state(struct device *dev) 125 { 126 /* 127 * All devices have now been attached/probed to the PM domain topology, 128 * hence it's fine to allow domain states to be picked. 129 */ 130 psci_pd_allow_domain_state = true; 131 } 132 133 static const struct of_device_id psci_of_match[] = { 134 { .compatible = "arm,psci-1.0" }, 135 {} 136 }; 137 138 static int psci_cpuidle_domain_probe(struct platform_device *pdev) 139 { 140 struct device_node *np = pdev->dev.of_node; 141 struct device_node *node; 142 bool use_osi = psci_has_osi_support(); 143 int ret = 0, pd_count = 0; 144 145 if (!np) 146 return -ENODEV; 147 148 /* 149 * Parse child nodes for the "#power-domain-cells" property and 150 * initialize a genpd/genpd-of-provider pair when it's found. 151 */ 152 for_each_child_of_node(np, node) { 153 if (!of_property_present(node, "#power-domain-cells")) 154 continue; 155 156 ret = psci_pd_init(node, use_osi); 157 if (ret) { 158 of_node_put(node); 159 goto exit; 160 } 161 162 pd_count++; 163 } 164 165 /* Bail out if not using the hierarchical CPU topology. */ 166 if (!pd_count) 167 return 0; 168 169 /* Link genpd masters/subdomains to model the CPU topology. */ 170 ret = dt_idle_pd_init_topology(np); 171 if (ret) 172 goto remove_pd; 173 174 /* let's try to enable OSI. */ 175 ret = psci_set_osi_mode(use_osi); 176 if (ret) 177 goto remove_pd; 178 179 pr_info("Initialized CPU PM domain topology using %s mode\n", 180 use_osi ? "OSI" : "PC"); 181 return 0; 182 183 remove_pd: 184 dt_idle_pd_remove_topology(np); 185 psci_pd_remove(); 186 exit: 187 pr_err("failed to create CPU PM domains ret=%d\n", ret); 188 return ret; 189 } 190 191 static struct platform_driver psci_cpuidle_domain_driver = { 192 .probe = psci_cpuidle_domain_probe, 193 .driver = { 194 .name = "psci-cpuidle-domain", 195 .of_match_table = psci_of_match, 196 .sync_state = psci_cpuidle_domain_sync_state, 197 }, 198 }; 199 200 static int __init psci_idle_init_domains(void) 201 { 202 return platform_driver_register(&psci_cpuidle_domain_driver); 203 } 204 core_initcall(psci_idle_init_domains); 205