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;
  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         return 0;
 147
 148 out_clk_put:
 149         clk_put(cpu_clk);
 150
 151         return ret;
 152 }
 153
 154 static int cpufreq_online(struct cpufreq_policy *policy)
 155 {
 156         /* We did light-weight tear down earlier, nothing to do here */
 157         return 0;
 158 }
 159
 160 static int cpufreq_offline(struct cpufreq_policy *policy)
 161 {
 162         /*
 163          * Preserve policy->driver_data and don't free resources on light-weight
 164          * tear down.
 165          */
 166         return 0;
 167 }
 168
 169 static int cpufreq_exit(struct cpufreq_policy *policy)
 170 {
 171         clk_put(policy->clk);
 172         return 0;
 173 }
 174
 175 static struct cpufreq_driver dt_cpufreq_driver = {
 176         .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK |
 177                  CPUFREQ_IS_COOLING_DEV,
 178         .verify = cpufreq_generic_frequency_table_verify,
 179         .target_index = set_target,
 180         .get = cpufreq_generic_get,
 181         .init = cpufreq_init,
 182         .exit = cpufreq_exit,
 183         .online = cpufreq_online,
 184         .offline = cpufreq_offline,
 185         .register_em = cpufreq_register_em_with_opp,
 186         .name = "cpufreq-dt",
 187         .attr = cpufreq_dt_attr,
 188         .suspend = cpufreq_generic_suspend,
 189 };
 190
 191 static int dt_cpufreq_early_init(struct device *dev, int cpu)
 192 {
 193         struct private_data *priv;
 194         struct device *cpu_dev;
 195         bool fallback = false;
 196         const char *reg_name[] = { NULL, NULL };
 197         int ret;
 198
 199         /* Check if this CPU is already covered by some other policy */
 200         if (cpufreq_dt_find_data(cpu))
 201                 return 0;
 202
 203         cpu_dev = get_cpu_device(cpu);
 204         if (!cpu_dev)
 205                 return -EPROBE_DEFER;
 206
 207         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 208         if (!priv)
 209                 return -ENOMEM;
 210
 211         if (!alloc_cpumask_var(&priv->cpus, GFP_KERNEL))
 212                 return -ENOMEM;
 213
 214         cpumask_set_cpu(cpu, priv->cpus);
 215         priv->cpu_dev = cpu_dev;
 216
 217         /*
 218          * OPP layer will be taking care of regulators now, but it needs to know
 219          * the name of the regulator first.
 220          */
 221         reg_name[0] = find_supply_name(cpu_dev);
 222         if (reg_name[0]) {
 223                 priv->opp_token = dev_pm_opp_set_regulators(cpu_dev, reg_name);
 224                 if (priv->opp_token < 0) {
 225                         ret = priv->opp_token;
 226                         if (ret != -EPROBE_DEFER)
 227                                 dev_err(cpu_dev, "failed to set regulators: %d\n",
 228                                         ret);
 229                         goto free_cpumask;
 230                 }
 231         }
 232
 233         /* Get OPP-sharing information from "operating-points-v2" bindings */
 234         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->cpus);
 235         if (ret) {
 236                 if (ret != -ENOENT)
 237                         goto out;
 238
 239                 /*
 240                  * operating-points-v2 not supported, fallback to all CPUs share
 241                  * OPP for backward compatibility if the platform hasn't set
 242                  * sharing CPUs.
 243                  */
 244                 if (dev_pm_opp_get_sharing_cpus(cpu_dev, priv->cpus))
 245                         fallback = true;
 246         }
 247
 248         /*
 249          * Initialize OPP tables for all priv->cpus. They will be shared by
 250          * all CPUs which have marked their CPUs shared with OPP bindings.
 251          *
 252          * For platforms not using operating-points-v2 bindings, we do this
 253          * before updating priv->cpus. Otherwise, we will end up creating
 254          * duplicate OPPs for the CPUs.
 255          *
 256          * OPPs might be populated at runtime, don't fail for error here unless
 257          * it is -EPROBE_DEFER.
 258          */
 259         ret = dev_pm_opp_of_cpumask_add_table(priv->cpus);
 260         if (!ret) {
 261                 priv->have_static_opps = true;
 262         } else if (ret == -EPROBE_DEFER) {
 263                 goto out;
 264         }
 265
 266         /*
 267          * The OPP table must be initialized, statically or dynamically, by this
 268          * point.
 269          */
 270         ret = dev_pm_opp_get_opp_count(cpu_dev);
 271         if (ret <= 0) {
 272                 dev_err(cpu_dev, "OPP table can't be empty\n");
 273                 ret = -ENODEV;
 274                 goto out;
 275         }
 276
 277         if (fallback) {
 278                 cpumask_setall(priv->cpus);
 279                 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->cpus);
 280                 if (ret)
 281                         dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 282                                 __func__, ret);
 283         }
 284
 285         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &priv->freq_table);
 286         if (ret) {
 287                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 288                 goto out;
 289         }
 290
 291         list_add(&priv->node, &priv_list);
 292         return 0;
 293
 294 out:
 295         if (priv->have_static_opps)
 296                 dev_pm_opp_of_cpumask_remove_table(priv->cpus);
 297         dev_pm_opp_put_regulators(priv->opp_token);
 298 free_cpumask:
 299         free_cpumask_var(priv->cpus);
 300         return ret;
 301 }
 302
 303 static void dt_cpufreq_release(void)
 304 {
 305         struct private_data *priv, *tmp;
 306
 307         list_for_each_entry_safe(priv, tmp, &priv_list, node) {
 308                 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &priv->freq_table);
 309                 if (priv->have_static_opps)
 310                         dev_pm_opp_of_cpumask_remove_table(priv->cpus);
 311                 dev_pm_opp_put_regulators(priv->opp_token);
 312                 free_cpumask_var(priv->cpus);
 313                 list_del(&priv->node);
 314         }
 315 }
 316
 317 static int dt_cpufreq_probe(struct platform_device *pdev)
 318 {
 319         struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev);
 320         int ret, cpu;
 321
 322         /* Request resources early so we can return in case of -EPROBE_DEFER */
 323         for_each_possible_cpu(cpu) {
 324                 ret = dt_cpufreq_early_init(&pdev->dev, cpu);
 325                 if (ret)
 326                         goto err;
 327         }
 328
 329         if (data) {
 330                 if (data->have_governor_per_policy)
 331                         dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY;
 332
 333                 dt_cpufreq_driver.resume = data->resume;
 334                 if (data->suspend)
 335                         dt_cpufreq_driver.suspend = data->suspend;
 336                 if (data->get_intermediate) {
 337                         dt_cpufreq_driver.target_intermediate = data->target_intermediate;
 338                         dt_cpufreq_driver.get_intermediate = data->get_intermediate;
 339                 }
 340         }
 341
 342         ret = cpufreq_register_driver(&dt_cpufreq_driver);
 343         if (ret) {
 344                 dev_err(&pdev->dev, "failed register driver: %d\n", ret);
 345                 goto err;
 346         }
 347
 348         return 0;
 349 err:
 350         dt_cpufreq_release();
 351         return ret;
 352 }
 353
 354 static int dt_cpufreq_remove(struct platform_device *pdev)
 355 {
 356         cpufreq_unregister_driver(&dt_cpufreq_driver);
 357         dt_cpufreq_release();
 358         return 0;
 359 }
 360
 361 static struct platform_driver dt_cpufreq_platdrv = {
 362         .driver = {
 363                 .name   = "cpufreq-dt",
 364         },
 365         .probe          = dt_cpufreq_probe,
 366         .remove         = dt_cpufreq_remove,
 367 };
 368 module_platform_driver(dt_cpufreq_platdrv);
 369
 370 MODULE_ALIAS("platform:cpufreq-dt");
 371 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 372 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 373 MODULE_DESCRIPTION("Generic cpufreq driver");
 374 MODULE_LICENSE("GPL");