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
  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_parse_state_nodes(struct genpd_power_state *states,
  51                                      int state_count)
  52 {
  53         int i, ret;
  54         u32 psci_state, *psci_state_buf;
  55
  56         for (i = 0; i < state_count; i++) {
  57                 ret = psci_dt_parse_state_node(to_of_node(states[i].fwnode),
  58                                         &psci_state);
  59                 if (ret)
  60                         goto free_state;
  61
  62                 psci_state_buf = kmalloc(sizeof(u32), GFP_KERNEL);
  63                 if (!psci_state_buf) {
  64                         ret = -ENOMEM;
  65                         goto free_state;
  66                 }
  67                 *psci_state_buf = psci_state;
  68                 states[i].data = psci_state_buf;
  69         }
  70
  71         return 0;
  72
  73 free_state:
  74         i--;
  75         for (; i >= 0; i--)
  76                 kfree(states[i].data);
  77         return ret;
  78 }
  79
  80 static int psci_pd_parse_states(struct device_node *np,
  81                         struct genpd_power_state **states, int *state_count)
  82 {
  83         int ret;
  84
  85         /* Parse the domain idle states. */
  86         ret = of_genpd_parse_idle_states(np, states, state_count);
  87         if (ret)
  88                 return ret;
  89
  90         /* Fill out the PSCI specifics for each found state. */
  91         ret = psci_pd_parse_state_nodes(*states, *state_count);
  92         if (ret)
  93                 kfree(*states);
  94
  95         return ret;
  96 }
  97
  98 static void psci_pd_free_states(struct genpd_power_state *states,
  99                                 unsigned int state_count)
 100 {
 101         int i;
 102
 103         for (i = 0; i < state_count; i++)
 104                 kfree(states[i].data);
 105         kfree(states);
 106 }
 107
 108 static int psci_pd_init(struct device_node *np, bool use_osi)
 109 {
 110         struct generic_pm_domain *pd;
 111         struct psci_pd_provider *pd_provider;
 112         struct dev_power_governor *pd_gov;
 113         struct genpd_power_state *states = NULL;
 114         int ret = -ENOMEM, state_count = 0;
 115
 116         pd = kzalloc(sizeof(*pd), GFP_KERNEL);
 117         if (!pd)
 118                 goto out;
 119
 120         pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
 121         if (!pd_provider)
 122                 goto free_pd;
 123
 124         pd->name = kasprintf(GFP_KERNEL, "%pOF", np);
 125         if (!pd->name)
 126                 goto free_pd_prov;
 127
 128         /*
 129          * Parse the domain idle states and let genpd manage the state selection
 130          * for those being compatible with "domain-idle-state".
 131          */
 132         ret = psci_pd_parse_states(np, &states, &state_count);
 133         if (ret)
 134                 goto free_name;
 135
 136         pd->free_states = psci_pd_free_states;
 137         pd->name = kbasename(pd->name);
 138         pd->states = states;
 139         pd->state_count = state_count;
 140         pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
 141
 142         /* Allow power off when OSI has been successfully enabled. */
 143         if (use_osi)
 144                 pd->power_off = psci_pd_power_off;
 145         else
 146                 pd->flags |= GENPD_FLAG_ALWAYS_ON;
 147
 148         /* Use governor for CPU PM domains if it has some states to manage. */
 149         pd_gov = state_count > 0 ? &pm_domain_cpu_gov : NULL;
 150
 151         ret = pm_genpd_init(pd, pd_gov, false);
 152         if (ret) {
 153                 psci_pd_free_states(states, state_count);
 154                 goto free_name;
 155         }
 156
 157         ret = of_genpd_add_provider_simple(np, pd);
 158         if (ret)
 159                 goto remove_pd;
 160
 161         pd_provider->node = of_node_get(np);
 162         list_add(&pd_provider->link, &psci_pd_providers);
 163
 164         pr_debug("init PM domain %s\n", pd->name);
 165         return 0;
 166
 167 remove_pd:
 168         pm_genpd_remove(pd);
 169 free_name:
 170         kfree(pd->name);
 171 free_pd_prov:
 172         kfree(pd_provider);
 173 free_pd:
 174         kfree(pd);
 175 out:
 176         pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
 177         return ret;
 178 }
 179
 180 static void psci_pd_remove(void)
 181 {
 182         struct psci_pd_provider *pd_provider, *it;
 183         struct generic_pm_domain *genpd;
 184
 185         list_for_each_entry_safe(pd_provider, it, &psci_pd_providers, link) {
 186                 of_genpd_del_provider(pd_provider->node);
 187
 188                 genpd = of_genpd_remove_last(pd_provider->node);
 189                 if (!IS_ERR(genpd))
 190                         kfree(genpd);
 191
 192                 of_node_put(pd_provider->node);
 193                 list_del(&pd_provider->link);
 194                 kfree(pd_provider);
 195         }
 196 }
 197
 198 static int psci_pd_init_topology(struct device_node *np)
 199 {
 200         struct device_node *node;
 201         struct of_phandle_args child, parent;
 202         int ret;
 203
 204         for_each_child_of_node(np, node) {
 205                 if (of_parse_phandle_with_args(node, "power-domains",
 206                                         "#power-domain-cells", 0, &parent))
 207                         continue;
 208
 209                 child.np = node;
 210                 child.args_count = 0;
 211                 ret = of_genpd_add_subdomain(&parent, &child);
 212                 of_node_put(parent.np);
 213                 if (ret) {
 214                         of_node_put(node);
 215                         return ret;
 216                 }
 217         }
 218
 219         return 0;
 220 }
 221
 222 static bool psci_pd_try_set_osi_mode(void)
 223 {
 224         int ret;
 225
 226         if (!psci_has_osi_support())
 227                 return false;
 228
 229         ret = psci_set_osi_mode(true);
 230         if (ret) {
 231                 pr_warn("failed to enable OSI mode: %d\n", ret);
 232                 return false;
 233         }
 234
 235         return true;
 236 }
 237
 238 static void psci_cpuidle_domain_sync_state(struct device *dev)
 239 {
 240         /*
 241          * All devices have now been attached/probed to the PM domain topology,
 242          * hence it's fine to allow domain states to be picked.
 243          */
 244         psci_pd_allow_domain_state = true;
 245 }
 246
 247 static const struct of_device_id psci_of_match[] = {
 248         { .compatible = "arm,psci-1.0" },
 249         {}
 250 };
 251
 252 static int psci_cpuidle_domain_probe(struct platform_device *pdev)
 253 {
 254         struct device_node *np = pdev->dev.of_node;
 255         struct device_node *node;
 256         bool use_osi;
 257         int ret = 0, pd_count = 0;
 258
 259         if (!np)
 260                 return -ENODEV;
 261
 262         /* If OSI mode is supported, let's try to enable it. */
 263         use_osi = psci_pd_try_set_osi_mode();
 264
 265         /*
 266          * Parse child nodes for the "#power-domain-cells" property and
 267          * initialize a genpd/genpd-of-provider pair when it's found.
 268          */
 269         for_each_child_of_node(np, node) {
 270                 if (!of_find_property(node, "#power-domain-cells", NULL))
 271                         continue;
 272
 273                 ret = psci_pd_init(node, use_osi);
 274                 if (ret)
 275                         goto put_node;
 276
 277                 pd_count++;
 278         }
 279
 280         /* Bail out if not using the hierarchical CPU topology. */
 281         if (!pd_count)
 282                 goto no_pd;
 283
 284         /* Link genpd masters/subdomains to model the CPU topology. */
 285         ret = psci_pd_init_topology(np);
 286         if (ret)
 287                 goto remove_pd;
 288
 289         pr_info("Initialized CPU PM domain topology\n");
 290         return 0;
 291
 292 put_node:
 293         of_node_put(node);
 294 remove_pd:
 295         psci_pd_remove();
 296         pr_err("failed to create CPU PM domains ret=%d\n", ret);
 297 no_pd:
 298         if (use_osi)
 299                 psci_set_osi_mode(false);
 300         return ret;
 301 }
 302
 303 static struct platform_driver psci_cpuidle_domain_driver = {
 304         .probe  = psci_cpuidle_domain_probe,
 305         .driver = {
 306                 .name = "psci-cpuidle-domain",
 307                 .of_match_table = psci_of_match,
 308                 .sync_state = psci_cpuidle_domain_sync_state,
 309         },
 310 };
 311
 312 static int __init psci_idle_init_domains(void)
 313 {
 314         return platform_driver_register(&psci_cpuidle_domain_driver);
 315 }
 316 subsys_initcall(psci_idle_init_domains);
 317
 318 struct device *psci_dt_attach_cpu(int cpu)
 319 {
 320         struct device *dev;
 321
 322         dev = dev_pm_domain_attach_by_name(get_cpu_device(cpu), "psci");
 323         if (IS_ERR_OR_NULL(dev))
 324                 return dev;
 325
 326         pm_runtime_irq_safe(dev);
 327         if (cpu_online(cpu))
 328                 pm_runtime_get_sync(dev);
 329
 330         dev_pm_syscore_device(dev, true);
 331
 332         return dev;
 333 }
 334
 335 void psci_dt_detach_cpu(struct device *dev)
 336 {
 337         if (IS_ERR_OR_NULL(dev))
 338                 return;
 339
 340         dev_pm_domain_detach(dev, false);
 341 }