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 opp_table *opp_table;
  33         struct cpufreq_frequency_table *freq_table;
  34         bool have_static_opps;
  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;
  72         struct property *pp;
  73         int cpu = dev->id;
  74         const char *name = NULL;
  75
  76         np = of_node_get(dev->of_node);
  77
  78         /* This must be valid for sure */
  79         if (WARN_ON(!np))
  80                 return NULL;
  81
  82         /* Try "cpu0" for older DTs */
  83         if (!cpu) {
  84                 pp = of_find_property(np, "cpu0-supply", NULL);
  85                 if (pp) {
  86                         name = "cpu0";
  87                         goto node_put;
  88                 }
  89         }
  90
  91         pp = of_find_property(np, "cpu-supply", NULL);
  92         if (pp) {
  93                 name = "cpu";
  94                 goto node_put;
  95         }
  96
  97         dev_dbg(dev, "no regulator for cpu%d\n", cpu);
  98 node_put:
  99         of_node_put(np);
 100         return name;
 101 }
 102
 103 static int cpufreq_init(struct cpufreq_policy *policy)
 104 {
 105         struct private_data *priv;
 106         struct device *cpu_dev;
 107         struct clk *cpu_clk;
 108         unsigned int transition_latency;
 109         int ret;
 110
 111         priv = cpufreq_dt_find_data(policy->cpu);
 112         if (!priv) {
 113                 pr_err("failed to find data for cpu%d\n", policy->cpu);
 114                 return -ENODEV;
 115         }
 116         cpu_dev = priv->cpu_dev;
 117
 118         cpu_clk = clk_get(cpu_dev, NULL);
 119         if (IS_ERR(cpu_clk)) {
 120                 ret = PTR_ERR(cpu_clk);
 121                 dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret);
 122                 return ret;
 123         }
 124
 125         transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
 126         if (!transition_latency)
 127                 transition_latency = CPUFREQ_ETERNAL;
 128
 129         cpumask_copy(policy->cpus, priv->cpus);
 130         policy->driver_data = priv;
 131         policy->clk = cpu_clk;
 132         policy->freq_table = priv->freq_table;
 133         policy->suspend_freq = dev_pm_opp_get_suspend_opp_freq(cpu_dev) / 1000;
 134         policy->cpuinfo.transition_latency = transition_latency;
 135         policy->dvfs_possible_from_any_cpu = true;
 136
 137         /* Support turbo/boost mode */
 138         if (policy_has_boost_freq(policy)) {
 139                 /* This gets disabled by core on driver unregister */
 140                 ret = cpufreq_enable_boost_support();
 141                 if (ret)
 142                         goto out_clk_put;
 143                 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
 144         }
 145
 146         dev_pm_opp_of_register_em(cpu_dev, policy->cpus);
 147
 148         return 0;
 149
 150 out_clk_put:
 151         clk_put(cpu_clk);
 152
 153         return ret;
 154 }
 155
 156 static int cpufreq_online(struct cpufreq_policy *policy)
 157 {
 158         /* We did light-weight tear down earlier, nothing to do here */
 159         return 0;
 160 }
 161
 162 static int cpufreq_offline(struct cpufreq_policy *policy)
 163 {
 164         /*
 165          * Preserve policy->driver_data and don't free resources on light-weight
 166          * tear down.
 167          */
 168         return 0;
 169 }
 170
 171 static int cpufreq_exit(struct cpufreq_policy *policy)
 172 {
 173         clk_put(policy->clk);
 174         return 0;
 175 }
 176
 177 static struct cpufreq_driver dt_cpufreq_driver = {
 178         .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK |
 179                  CPUFREQ_IS_COOLING_DEV,
 180         .verify = cpufreq_generic_frequency_table_verify,
 181         .target_index = set_target,
 182         .get = cpufreq_generic_get,
 183         .init = cpufreq_init,
 184         .exit = cpufreq_exit,
 185         .online = cpufreq_online,
 186         .offline = cpufreq_offline,
 187         .name = "cpufreq-dt",
 188         .attr = cpufreq_dt_attr,
 189         .suspend = cpufreq_generic_suspend,
 190 };
 191
 192 static int dt_cpufreq_early_init(struct device *dev, int cpu)
 193 {
 194         struct private_data *priv;
 195         struct device *cpu_dev;
 196         bool fallback = false;
 197         const char *reg_name;
 198         int ret;
 199
 200         /* Check if this CPU is already covered by some other policy */
 201         if (cpufreq_dt_find_data(cpu))
 202                 return 0;
 203
 204         cpu_dev = get_cpu_device(cpu);
 205         if (!cpu_dev)
 206                 return -EPROBE_DEFER;
 207
 208         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 209         if (!priv)
 210                 return -ENOMEM;
 211
 212         if (!alloc_cpumask_var(&priv->cpus, GFP_KERNEL))
 213                 return -ENOMEM;
 214
 215         cpumask_set_cpu(cpu, priv->cpus);
 216         priv->cpu_dev = cpu_dev;
 217
 218         /*
 219          * OPP layer will be taking care of regulators now, but it needs to know
 220          * the name of the regulator first.
 221          */
 222         reg_name = find_supply_name(cpu_dev);
 223         if (reg_name) {
 224                 priv->opp_table = dev_pm_opp_set_regulators(cpu_dev, &reg_name,
 225                                                             1);
 226                 if (IS_ERR(priv->opp_table)) {
 227                         ret = PTR_ERR(priv->opp_table);
 228                         if (ret != -EPROBE_DEFER)
 229                                 dev_err(cpu_dev, "failed to set regulators: %d\n",
 230                                         ret);
 231                         goto free_cpumask;
 232                 }
 233         }
 234
 235         /* Get OPP-sharing information from "operating-points-v2" bindings */
 236         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->cpus);
 237         if (ret) {
 238                 if (ret != -ENOENT)
 239                         goto out;
 240
 241                 /*
 242                  * operating-points-v2 not supported, fallback to all CPUs share
 243                  * OPP for backward compatibility if the platform hasn't set
 244                  * sharing CPUs.
 245                  */
 246                 if (dev_pm_opp_get_sharing_cpus(cpu_dev, priv->cpus))
 247                         fallback = true;
 248         }
 249
 250         /*
 251          * Initialize OPP tables for all priv->cpus. They will be shared by
 252          * all CPUs which have marked their CPUs shared with OPP bindings.
 253          *
 254          * For platforms not using operating-points-v2 bindings, we do this
 255          * before updating priv->cpus. Otherwise, we will end up creating
 256          * duplicate OPPs for the CPUs.
 257          *
 258          * OPPs might be populated at runtime, don't fail for error here unless
 259          * it is -EPROBE_DEFER.
 260          */
 261         ret = dev_pm_opp_of_cpumask_add_table(priv->cpus);
 262         if (!ret) {
 263                 priv->have_static_opps = true;
 264         } else if (ret == -EPROBE_DEFER) {
 265                 goto out;
 266         }
 267
 268         /*
 269          * The OPP table must be initialized, statically or dynamically, by this
 270          * point.
 271          */
 272         ret = dev_pm_opp_get_opp_count(cpu_dev);
 273         if (ret <= 0) {
 274                 dev_err(cpu_dev, "OPP table can't be empty\n");
 275                 ret = -ENODEV;
 276                 goto out;
 277         }
 278
 279         if (fallback) {
 280                 cpumask_setall(priv->cpus);
 281                 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->cpus);
 282                 if (ret)
 283                         dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 284                                 __func__, ret);
 285         }
 286
 287         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &priv->freq_table);
 288         if (ret) {
 289                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 290                 goto out;
 291         }
 292
 293         list_add(&priv->node, &priv_list);
 294         return 0;
 295
 296 out:
 297         if (priv->have_static_opps)
 298                 dev_pm_opp_of_cpumask_remove_table(priv->cpus);
 299         dev_pm_opp_put_regulators(priv->opp_table);
 300 free_cpumask:
 301         free_cpumask_var(priv->cpus);
 302         return ret;
 303 }
 304
 305 static void dt_cpufreq_release(void)
 306 {
 307         struct private_data *priv, *tmp;
 308
 309         list_for_each_entry_safe(priv, tmp, &priv_list, node) {
 310                 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &priv->freq_table);
 311                 if (priv->have_static_opps)
 312                         dev_pm_opp_of_cpumask_remove_table(priv->cpus);
 313                 dev_pm_opp_put_regulators(priv->opp_table);
 314                 free_cpumask_var(priv->cpus);
 315                 list_del(&priv->node);
 316         }
 317 }
 318
 319 static int dt_cpufreq_probe(struct platform_device *pdev)
 320 {
 321         struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev);
 322         int ret, cpu;
 323
 324         /* Request resources early so we can return in case of -EPROBE_DEFER */
 325         for_each_possible_cpu(cpu) {
 326                 ret = dt_cpufreq_early_init(&pdev->dev, cpu);
 327                 if (ret)
 328                         goto err;
 329         }
 330
 331         if (data) {
 332                 if (data->have_governor_per_policy)
 333                         dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY;
 334
 335                 dt_cpufreq_driver.resume = data->resume;
 336                 if (data->suspend)
 337                         dt_cpufreq_driver.suspend = data->suspend;
 338                 if (data->get_intermediate) {
 339                         dt_cpufreq_driver.target_intermediate = data->target_intermediate;
 340                         dt_cpufreq_driver.get_intermediate = data->get_intermediate;
 341                 }
 342         }
 343
 344         ret = cpufreq_register_driver(&dt_cpufreq_driver);
 345         if (ret) {
 346                 dev_err(&pdev->dev, "failed register driver: %d\n", ret);
 347                 goto err;
 348         }
 349
 350         return 0;
 351 err:
 352         dt_cpufreq_release();
 353         return ret;
 354 }
 355
 356 static int dt_cpufreq_remove(struct platform_device *pdev)
 357 {
 358         cpufreq_unregister_driver(&dt_cpufreq_driver);
 359         dt_cpufreq_release();
 360         return 0;
 361 }
 362
 363 static struct platform_driver dt_cpufreq_platdrv = {
 364         .driver = {
 365                 .name   = "cpufreq-dt",
 366         },
 367         .probe          = dt_cpufreq_probe,
 368         .remove         = dt_cpufreq_remove,
 369 };
 370 module_platform_driver(dt_cpufreq_platdrv);
 371
 372 MODULE_ALIAS("platform:cpufreq-dt");
 373 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 374 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 375 MODULE_DESCRIPTION("Generic cpufreq driver");
 376 MODULE_LICENSE("GPL");