drivers/cpufreq/cpufreq-dt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2012 Freescale Semiconductor, Inc.
   4  *
   5  * Copyright (C) 2014 Linaro.
   6  * Viresh Kumar <viresh.kumar@linaro.org>
   7  */
   8
   9 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
  10
  11 #include <linux/clk.h>
  12 #include <linux/cpu.h>
  13 #include <linux/cpufreq.h>
  14 #include <linux/cpumask.h>
  15 #include <linux/err.h>
  16 #include <linux/list.h>
  17 #include <linux/module.h>
  18 #include <linux/of.h>
  19 #include <linux/pm_opp.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/regulator/consumer.h>
  22 #include <linux/slab.h>
  23 #include <linux/thermal.h>
  24
  25 #include "cpufreq-dt.h"
  26
  27 struct private_data {
  28         struct list_head node;
  29
  30         cpumask_var_t cpus;
  31         struct device *cpu_dev;
  32         struct cpufreq_frequency_table *freq_table;
  33         bool have_static_opps;
  34         int opp_token;
  35 };
  36
  37 static LIST_HEAD(priv_list);
  38
  39 static struct freq_attr *cpufreq_dt_attr[] = {
  40         &cpufreq_freq_attr_scaling_available_freqs,
  41         NULL,   /* Extra space for boost-attr if required */
  42         NULL,
  43 };
  44
  45 static struct private_data *cpufreq_dt_find_data(int cpu)
  46 {
  47         struct private_data *priv;
  48
  49         list_for_each_entry(priv, &priv_list, node) {
  50                 if (cpumask_test_cpu(cpu, priv->cpus))
  51                         return priv;
  52         }
  53
  54         return NULL;
  55 }
  56
  57 static int set_target(struct cpufreq_policy *policy, unsigned int index)
  58 {
  59         struct private_data *priv = policy->driver_data;
  60         unsigned long freq = policy->freq_table[index].frequency;
  61
  62         return dev_pm_opp_set_rate(priv->cpu_dev, freq * 1000);
  63 }
  64
  65 /*
  66  * An earlier version of opp-v1 bindings used to name the regulator
  67  * "cpu0-supply", we still need to handle that for backwards compatibility.
  68  */
  69 static const char *find_supply_name(struct device *dev)
  70 {
  71         struct device_node *np __free(device_node) = of_node_get(dev->of_node);
  72         int cpu = dev->id;
  73
  74         /* This must be valid for sure */
  75         if (WARN_ON(!np))
  76                 return NULL;
  77
  78         /* Try "cpu0" for older DTs */
  79         if (!cpu && of_property_present(np, "cpu0-supply"))
  80                 return "cpu0";
  81
  82         if (of_property_present(np, "cpu-supply"))
  83                 return "cpu";
  84
  85         dev_dbg(dev, "no regulator for cpu%d\n", cpu);
  86         return NULL;
  87 }
  88
  89 static int cpufreq_init(struct cpufreq_policy *policy)
  90 {
  91         struct private_data *priv;
  92         struct device *cpu_dev;
  93         struct clk *cpu_clk;
  94         unsigned int transition_latency;
  95         int ret;
  96
  97         priv = cpufreq_dt_find_data(policy->cpu);
  98         if (!priv) {
  99                 pr_err("failed to find data for cpu%d\n", policy->cpu);
 100                 return -ENODEV;
 101         }
 102         cpu_dev = priv->cpu_dev;
 103
 104         cpu_clk = clk_get(cpu_dev, NULL);
 105         if (IS_ERR(cpu_clk)) {
 106                 ret = PTR_ERR(cpu_clk);
 107                 dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret);
 108                 return ret;
 109         }
 110
 111         transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
 112         if (!transition_latency)
 113                 transition_latency = CPUFREQ_ETERNAL;
 114
 115         cpumask_copy(policy->cpus, priv->cpus);
 116         policy->driver_data = priv;
 117         policy->clk = cpu_clk;
 118         policy->freq_table = priv->freq_table;
 119         policy->suspend_freq = dev_pm_opp_get_suspend_opp_freq(cpu_dev) / 1000;
 120         policy->cpuinfo.transition_latency = transition_latency;
 121         policy->dvfs_possible_from_any_cpu = true;
 122
 123         /* Support turbo/boost mode */
 124         if (policy_has_boost_freq(policy)) {
 125                 /* This gets disabled by core on driver unregister */
 126                 ret = cpufreq_enable_boost_support();
 127                 if (ret)
 128                         goto out_clk_put;
 129                 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
 130         }
 131
 132         return 0;
 133
 134 out_clk_put:
 135         clk_put(cpu_clk);
 136
 137         return ret;
 138 }
 139
 140 static int cpufreq_online(struct cpufreq_policy *policy)
 141 {
 142         /* We did light-weight tear down earlier, nothing to do here */
 143         return 0;
 144 }
 145
 146 static int cpufreq_offline(struct cpufreq_policy *policy)
 147 {
 148         /*
 149          * Preserve policy->driver_data and don't free resources on light-weight
 150          * tear down.
 151          */
 152         return 0;
 153 }
 154
 155 static void cpufreq_exit(struct cpufreq_policy *policy)
 156 {
 157         clk_put(policy->clk);
 158 }
 159
 160 static struct cpufreq_driver dt_cpufreq_driver = {
 161         .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK |
 162                  CPUFREQ_IS_COOLING_DEV,
 163         .verify = cpufreq_generic_frequency_table_verify,
 164         .target_index = set_target,
 165         .get = cpufreq_generic_get,
 166         .init = cpufreq_init,
 167         .exit = cpufreq_exit,
 168         .online = cpufreq_online,
 169         .offline = cpufreq_offline,
 170         .register_em = cpufreq_register_em_with_opp,
 171         .name = "cpufreq-dt",
 172         .attr = cpufreq_dt_attr,
 173         .suspend = cpufreq_generic_suspend,
 174 };
 175
 176 static int dt_cpufreq_early_init(struct device *dev, int cpu)
 177 {
 178         struct private_data *priv;
 179         struct device *cpu_dev;
 180         bool fallback = false;
 181         const char *reg_name[] = { NULL, NULL };
 182         int ret;
 183
 184         /* Check if this CPU is already covered by some other policy */
 185         if (cpufreq_dt_find_data(cpu))
 186                 return 0;
 187
 188         cpu_dev = get_cpu_device(cpu);
 189         if (!cpu_dev)
 190                 return -EPROBE_DEFER;
 191
 192         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 193         if (!priv)
 194                 return -ENOMEM;
 195
 196         if (!zalloc_cpumask_var(&priv->cpus, GFP_KERNEL))
 197                 return -ENOMEM;
 198
 199         cpumask_set_cpu(cpu, priv->cpus);
 200         priv->cpu_dev = cpu_dev;
 201
 202         /*
 203          * OPP layer will be taking care of regulators now, but it needs to know
 204          * the name of the regulator first.
 205          */
 206         reg_name[0] = find_supply_name(cpu_dev);
 207         if (reg_name[0]) {
 208                 priv->opp_token = dev_pm_opp_set_regulators(cpu_dev, reg_name);
 209                 if (priv->opp_token < 0) {
 210                         ret = dev_err_probe(cpu_dev, priv->opp_token,
 211                                             "failed to set regulators\n");
 212                         goto free_cpumask;
 213                 }
 214         }
 215
 216         /* Get OPP-sharing information from "operating-points-v2" bindings */
 217         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->cpus);
 218         if (ret) {
 219                 if (ret != -ENOENT)
 220                         goto out;
 221
 222                 /*
 223                  * operating-points-v2 not supported, fallback to all CPUs share
 224                  * OPP for backward compatibility if the platform hasn't set
 225                  * sharing CPUs.
 226                  */
 227                 if (dev_pm_opp_get_sharing_cpus(cpu_dev, priv->cpus))
 228                         fallback = true;
 229         }
 230
 231         /*
 232          * Initialize OPP tables for all priv->cpus. They will be shared by
 233          * all CPUs which have marked their CPUs shared with OPP bindings.
 234          *
 235          * For platforms not using operating-points-v2 bindings, we do this
 236          * before updating priv->cpus. Otherwise, we will end up creating
 237          * duplicate OPPs for the CPUs.
 238          *
 239          * OPPs might be populated at runtime, don't fail for error here unless
 240          * it is -EPROBE_DEFER.
 241          */
 242         ret = dev_pm_opp_of_cpumask_add_table(priv->cpus);
 243         if (!ret) {
 244                 priv->have_static_opps = true;
 245         } else if (ret == -EPROBE_DEFER) {
 246                 goto out;
 247         }
 248
 249         /*
 250          * The OPP table must be initialized, statically or dynamically, by this
 251          * point.
 252          */
 253         ret = dev_pm_opp_get_opp_count(cpu_dev);
 254         if (ret <= 0) {
 255                 dev_err(cpu_dev, "OPP table can't be empty\n");
 256                 ret = -ENODEV;
 257                 goto out;
 258         }
 259
 260         if (fallback) {
 261                 cpumask_setall(priv->cpus);
 262                 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->cpus);
 263                 if (ret)
 264                         dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 265                                 __func__, ret);
 266         }
 267
 268         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &priv->freq_table);
 269         if (ret) {
 270                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 271                 goto out;
 272         }
 273
 274         list_add(&priv->node, &priv_list);
 275         return 0;
 276
 277 out:
 278         if (priv->have_static_opps)
 279                 dev_pm_opp_of_cpumask_remove_table(priv->cpus);
 280         dev_pm_opp_put_regulators(priv->opp_token);
 281 free_cpumask:
 282         free_cpumask_var(priv->cpus);
 283         return ret;
 284 }
 285
 286 static void dt_cpufreq_release(void)
 287 {
 288         struct private_data *priv, *tmp;
 289
 290         list_for_each_entry_safe(priv, tmp, &priv_list, node) {
 291                 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &priv->freq_table);
 292                 if (priv->have_static_opps)
 293                         dev_pm_opp_of_cpumask_remove_table(priv->cpus);
 294                 dev_pm_opp_put_regulators(priv->opp_token);
 295                 free_cpumask_var(priv->cpus);
 296                 list_del(&priv->node);
 297         }
 298 }
 299
 300 static int dt_cpufreq_probe(struct platform_device *pdev)
 301 {
 302         struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev);
 303         int ret, cpu;
 304
 305         /* Request resources early so we can return in case of -EPROBE_DEFER */
 306         for_each_possible_cpu(cpu) {
 307                 ret = dt_cpufreq_early_init(&pdev->dev, cpu);
 308                 if (ret)
 309                         goto err;
 310         }
 311
 312         if (data) {
 313                 if (data->have_governor_per_policy)
 314                         dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY;
 315
 316                 dt_cpufreq_driver.resume = data->resume;
 317                 if (data->suspend)
 318                         dt_cpufreq_driver.suspend = data->suspend;
 319                 if (data->get_intermediate) {
 320                         dt_cpufreq_driver.target_intermediate = data->target_intermediate;
 321                         dt_cpufreq_driver.get_intermediate = data->get_intermediate;
 322                 }
 323         }
 324
 325         ret = cpufreq_register_driver(&dt_cpufreq_driver);
 326         if (ret) {
 327                 dev_err(&pdev->dev, "failed register driver: %d\n", ret);
 328                 goto err;
 329         }
 330
 331         return 0;
 332 err:
 333         dt_cpufreq_release();
 334         return ret;
 335 }
 336
 337 static void dt_cpufreq_remove(struct platform_device *pdev)
 338 {
 339         cpufreq_unregister_driver(&dt_cpufreq_driver);
 340         dt_cpufreq_release();
 341 }
 342
 343 static struct platform_driver dt_cpufreq_platdrv = {
 344         .driver = {
 345                 .name   = "cpufreq-dt",
 346         },
 347         .probe          = dt_cpufreq_probe,
 348         .remove_new     = dt_cpufreq_remove,
 349 };
 350 module_platform_driver(dt_cpufreq_platdrv);
 351
 352 MODULE_ALIAS("platform:cpufreq-dt");
 353 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 354 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 355 MODULE_DESCRIPTION("Generic cpufreq driver");
 356 MODULE_LICENSE("GPL");