drivers/cpuidle/cpuidle-psci-domain.c

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