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