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 pr_warn("failed to enable OSI mode: %d\n", ret); 129 return false; 130 } 131 132 return true; 133 } 134 135 static void psci_cpuidle_domain_sync_state(struct device *dev) 136 { 137 /* 138 * All devices have now been attached/probed to the PM domain topology, 139 * hence it's fine to allow domain states to be picked. 140 */ 141 psci_pd_allow_domain_state = true; 142 } 143 144 static const struct of_device_id psci_of_match[] = { 145 { .compatible = "arm,psci-1.0" }, 146 {} 147 }; 148 149 static int psci_cpuidle_domain_probe(struct platform_device *pdev) 150 { 151 struct device_node *np = pdev->dev.of_node; 152 struct device_node *node; 153 bool use_osi; 154 int ret = 0, pd_count = 0; 155 156 if (!np) 157 return -ENODEV; 158 159 /* If OSI mode is supported, let's try to enable it. */ 160 use_osi = psci_pd_try_set_osi_mode(); 161 162 /* 163 * Parse child nodes for the "#power-domain-cells" property and 164 * initialize a genpd/genpd-of-provider pair when it's found. 165 */ 166 for_each_child_of_node(np, node) { 167 if (!of_find_property(node, "#power-domain-cells", NULL)) 168 continue; 169 170 ret = psci_pd_init(node, use_osi); 171 if (ret) 172 goto put_node; 173 174 pd_count++; 175 } 176 177 /* Bail out if not using the hierarchical CPU topology. */ 178 if (!pd_count) 179 goto no_pd; 180 181 /* Link genpd masters/subdomains to model the CPU topology. */ 182 ret = dt_idle_pd_init_topology(np); 183 if (ret) 184 goto remove_pd; 185 186 pr_info("Initialized CPU PM domain topology\n"); 187 return 0; 188 189 put_node: 190 of_node_put(node); 191 remove_pd: 192 psci_pd_remove(); 193 pr_err("failed to create CPU PM domains ret=%d\n", ret); 194 no_pd: 195 if (use_osi) 196 psci_set_osi_mode(false); 197 return ret; 198 } 199 200 static struct platform_driver psci_cpuidle_domain_driver = { 201 .probe = psci_cpuidle_domain_probe, 202 .driver = { 203 .name = "psci-cpuidle-domain", 204 .of_match_table = psci_of_match, 205 .sync_state = psci_cpuidle_domain_sync_state, 206 }, 207 }; 208 209 static int __init psci_idle_init_domains(void) 210 { 211 return platform_driver_register(&psci_cpuidle_domain_driver); 212 } 213 subsys_initcall(psci_idle_init_domains); 214