drivers/cpufreq/cpufreq-dt.c

   1 /*
   2  * Copyright (C) 2012 Freescale Semiconductor, Inc.
   3  *
   4  * Copyright (C) 2014 Linaro.
   5  * Viresh Kumar <viresh.kumar@linaro.org>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/clk.h>
  15 #include <linux/cpu.h>
  16 #include <linux/cpu_cooling.h>
  17 #include <linux/cpufreq.h>
  18 #include <linux/cpumask.h>
  19 #include <linux/err.h>
  20 #include <linux/module.h>
  21 #include <linux/of.h>
  22 #include <linux/pm_opp.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/regulator/consumer.h>
  25 #include <linux/slab.h>
  26 #include <linux/thermal.h>
  27
  28 #include "cpufreq-dt.h"
  29
  30 struct private_data {
  31         struct opp_table *opp_table;
  32         struct device *cpu_dev;
  33         struct thermal_cooling_device *cdev;
  34         const char *reg_name;
  35 };
  36
  37 static struct freq_attr *cpufreq_dt_attr[] = {
  38         &cpufreq_freq_attr_scaling_available_freqs,
  39         NULL,   /* Extra space for boost-attr if required */
  40         NULL,
  41 };
  42
  43 static int set_target(struct cpufreq_policy *policy, unsigned int index)
  44 {
  45         struct private_data *priv = policy->driver_data;
  46
  47         return dev_pm_opp_set_rate(priv->cpu_dev,
  48                                    policy->freq_table[index].frequency * 1000);
  49 }
  50
  51 /*
  52  * An earlier version of opp-v1 bindings used to name the regulator
  53  * "cpu0-supply", we still need to handle that for backwards compatibility.
  54  */
  55 static const char *find_supply_name(struct device *dev)
  56 {
  57         struct device_node *np;
  58         struct property *pp;
  59         int cpu = dev->id;
  60         const char *name = NULL;
  61
  62         np = of_node_get(dev->of_node);
  63
  64         /* This must be valid for sure */
  65         if (WARN_ON(!np))
  66                 return NULL;
  67
  68         /* Try "cpu0" for older DTs */
  69         if (!cpu) {
  70                 pp = of_find_property(np, "cpu0-supply", NULL);
  71                 if (pp) {
  72                         name = "cpu0";
  73                         goto node_put;
  74                 }
  75         }
  76
  77         pp = of_find_property(np, "cpu-supply", NULL);
  78         if (pp) {
  79                 name = "cpu";
  80                 goto node_put;
  81         }
  82
  83         dev_dbg(dev, "no regulator for cpu%d\n", cpu);
  84 node_put:
  85         of_node_put(np);
  86         return name;
  87 }
  88
  89 static int resources_available(void)
  90 {
  91         struct device *cpu_dev;
  92         struct regulator *cpu_reg;
  93         struct clk *cpu_clk;
  94         int ret = 0;
  95         const char *name;
  96
  97         cpu_dev = get_cpu_device(0);
  98         if (!cpu_dev) {
  99                 pr_err("failed to get cpu0 device\n");
 100                 return -ENODEV;
 101         }
 102
 103         cpu_clk = clk_get(cpu_dev, NULL);
 104         ret = PTR_ERR_OR_ZERO(cpu_clk);
 105         if (ret) {
 106                 /*
 107                  * If cpu's clk node is present, but clock is not yet
 108                  * registered, we should try defering probe.
 109                  */
 110                 if (ret == -EPROBE_DEFER)
 111                         dev_dbg(cpu_dev, "clock not ready, retry\n");
 112                 else
 113                         dev_err(cpu_dev, "failed to get clock: %d\n", ret);
 114
 115                 return ret;
 116         }
 117
 118         clk_put(cpu_clk);
 119
 120         name = find_supply_name(cpu_dev);
 121         /* Platform doesn't require regulator */
 122         if (!name)
 123                 return 0;
 124
 125         cpu_reg = regulator_get_optional(cpu_dev, name);
 126         ret = PTR_ERR_OR_ZERO(cpu_reg);
 127         if (ret) {
 128                 /*
 129                  * If cpu's regulator supply node is present, but regulator is
 130                  * not yet registered, we should try defering probe.
 131                  */
 132                 if (ret == -EPROBE_DEFER)
 133                         dev_dbg(cpu_dev, "cpu0 regulator not ready, retry\n");
 134                 else
 135                         dev_dbg(cpu_dev, "no regulator for cpu0: %d\n", ret);
 136
 137                 return ret;
 138         }
 139
 140         regulator_put(cpu_reg);
 141         return 0;
 142 }
 143
 144 static int cpufreq_init(struct cpufreq_policy *policy)
 145 {
 146         struct cpufreq_frequency_table *freq_table;
 147         struct opp_table *opp_table = NULL;
 148         struct private_data *priv;
 149         struct device *cpu_dev;
 150         struct clk *cpu_clk;
 151         unsigned int transition_latency;
 152         bool fallback = false;
 153         const char *name;
 154         int ret;
 155
 156         cpu_dev = get_cpu_device(policy->cpu);
 157         if (!cpu_dev) {
 158                 pr_err("failed to get cpu%d device\n", policy->cpu);
 159                 return -ENODEV;
 160         }
 161
 162         cpu_clk = clk_get(cpu_dev, NULL);
 163         if (IS_ERR(cpu_clk)) {
 164                 ret = PTR_ERR(cpu_clk);
 165                 dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret);
 166                 return ret;
 167         }
 168
 169         /* Get OPP-sharing information from "operating-points-v2" bindings */
 170         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus);
 171         if (ret) {
 172                 if (ret != -ENOENT)
 173                         goto out_put_clk;
 174
 175                 /*
 176                  * operating-points-v2 not supported, fallback to old method of
 177                  * finding shared-OPPs for backward compatibility if the
 178                  * platform hasn't set sharing CPUs.
 179                  */
 180                 if (dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus))
 181                         fallback = true;
 182         }
 183
 184         /*
 185          * OPP layer will be taking care of regulators now, but it needs to know
 186          * the name of the regulator first.
 187          */
 188         name = find_supply_name(cpu_dev);
 189         if (name) {
 190                 opp_table = dev_pm_opp_set_regulators(cpu_dev, &name, 1);
 191                 if (IS_ERR(opp_table)) {
 192                         ret = PTR_ERR(opp_table);
 193                         dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n",
 194                                 policy->cpu, ret);
 195                         goto out_put_clk;
 196                 }
 197         }
 198
 199         /*
 200          * Initialize OPP tables for all policy->cpus. They will be shared by
 201          * all CPUs which have marked their CPUs shared with OPP bindings.
 202          *
 203          * For platforms not using operating-points-v2 bindings, we do this
 204          * before updating policy->cpus. Otherwise, we will end up creating
 205          * duplicate OPPs for policy->cpus.
 206          *
 207          * OPPs might be populated at runtime, don't check for error here
 208          */
 209         dev_pm_opp_of_cpumask_add_table(policy->cpus);
 210
 211         /*
 212          * But we need OPP table to function so if it is not there let's
 213          * give platform code chance to provide it for us.
 214          */
 215         ret = dev_pm_opp_get_opp_count(cpu_dev);
 216         if (ret <= 0) {
 217                 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
 218                 ret = -EPROBE_DEFER;
 219                 goto out_free_opp;
 220         }
 221
 222         if (fallback) {
 223                 cpumask_setall(policy->cpus);
 224
 225                 /*
 226                  * OPP tables are initialized only for policy->cpu, do it for
 227                  * others as well.
 228                  */
 229                 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
 230                 if (ret)
 231                         dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 232                                 __func__, ret);
 233         }
 234
 235         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 236         if (!priv) {
 237                 ret = -ENOMEM;
 238                 goto out_free_opp;
 239         }
 240
 241         priv->reg_name = name;
 242         priv->opp_table = opp_table;
 243
 244         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 245         if (ret) {
 246                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 247                 goto out_free_priv;
 248         }
 249
 250         priv->cpu_dev = cpu_dev;
 251         policy->driver_data = priv;
 252         policy->clk = cpu_clk;
 253
 254         policy->suspend_freq = dev_pm_opp_get_suspend_opp_freq(cpu_dev) / 1000;
 255
 256         ret = cpufreq_table_validate_and_show(policy, freq_table);
 257         if (ret) {
 258                 dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
 259                         ret);
 260                 goto out_free_cpufreq_table;
 261         }
 262
 263         /* Support turbo/boost mode */
 264         if (policy_has_boost_freq(policy)) {
 265                 /* This gets disabled by core on driver unregister */
 266                 ret = cpufreq_enable_boost_support();
 267                 if (ret)
 268                         goto out_free_cpufreq_table;
 269                 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
 270         }
 271
 272         transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
 273         if (!transition_latency)
 274                 transition_latency = CPUFREQ_ETERNAL;
 275
 276         policy->cpuinfo.transition_latency = transition_latency;
 277
 278         return 0;
 279
 280 out_free_cpufreq_table:
 281         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 282 out_free_priv:
 283         kfree(priv);
 284 out_free_opp:
 285         dev_pm_opp_of_cpumask_remove_table(policy->cpus);
 286         if (name)
 287                 dev_pm_opp_put_regulators(opp_table);
 288 out_put_clk:
 289         clk_put(cpu_clk);
 290
 291         return ret;
 292 }
 293
 294 static int cpufreq_exit(struct cpufreq_policy *policy)
 295 {
 296         struct private_data *priv = policy->driver_data;
 297
 298         cpufreq_cooling_unregister(priv->cdev);
 299         dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
 300         dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
 301         if (priv->reg_name)
 302                 dev_pm_opp_put_regulators(priv->opp_table);
 303
 304         clk_put(policy->clk);
 305         kfree(priv);
 306
 307         return 0;
 308 }
 309
 310 static void cpufreq_ready(struct cpufreq_policy *policy)
 311 {
 312         struct private_data *priv = policy->driver_data;
 313         struct device_node *np = of_node_get(priv->cpu_dev->of_node);
 314
 315         if (WARN_ON(!np))
 316                 return;
 317
 318         /*
 319          * For now, just loading the cooling device;
 320          * thermal DT code takes care of matching them.
 321          */
 322         if (of_find_property(np, "#cooling-cells", NULL)) {
 323                 u32 power_coefficient = 0;
 324
 325                 of_property_read_u32(np, "dynamic-power-coefficient",
 326                                      &power_coefficient);
 327
 328                 priv->cdev = of_cpufreq_power_cooling_register(np,
 329                                 policy->related_cpus, power_coefficient, NULL);
 330                 if (IS_ERR(priv->cdev)) {
 331                         dev_err(priv->cpu_dev,
 332                                 "running cpufreq without cooling device: %ld\n",
 333                                 PTR_ERR(priv->cdev));
 334
 335                         priv->cdev = NULL;
 336                 }
 337         }
 338
 339         of_node_put(np);
 340 }
 341
 342 static struct cpufreq_driver dt_cpufreq_driver = {
 343         .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 344         .verify = cpufreq_generic_frequency_table_verify,
 345         .target_index = set_target,
 346         .get = cpufreq_generic_get,
 347         .init = cpufreq_init,
 348         .exit = cpufreq_exit,
 349         .ready = cpufreq_ready,
 350         .name = "cpufreq-dt",
 351         .attr = cpufreq_dt_attr,
 352         .suspend = cpufreq_generic_suspend,
 353 };
 354
 355 static int dt_cpufreq_probe(struct platform_device *pdev)
 356 {
 357         struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev);
 358         int ret;
 359
 360         /*
 361          * All per-cluster (CPUs sharing clock/voltages) initialization is done
 362          * from ->init(). In probe(), we just need to make sure that clk and
 363          * regulators are available. Else defer probe and retry.
 364          *
 365          * FIXME: Is checking this only for CPU0 sufficient ?
 366          */
 367         ret = resources_available();
 368         if (ret)
 369                 return ret;
 370
 371         if (data && data->have_governor_per_policy)
 372                 dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY;
 373
 374         ret = cpufreq_register_driver(&dt_cpufreq_driver);
 375         if (ret)
 376                 dev_err(&pdev->dev, "failed register driver: %d\n", ret);
 377
 378         return ret;
 379 }
 380
 381 static int dt_cpufreq_remove(struct platform_device *pdev)
 382 {
 383         cpufreq_unregister_driver(&dt_cpufreq_driver);
 384         return 0;
 385 }
 386
 387 static struct platform_driver dt_cpufreq_platdrv = {
 388         .driver = {
 389                 .name   = "cpufreq-dt",
 390         },
 391         .probe          = dt_cpufreq_probe,
 392         .remove         = dt_cpufreq_remove,
 393 };
 394 module_platform_driver(dt_cpufreq_platdrv);
 395
 396 MODULE_ALIAS("platform:cpufreq-dt");
 397 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 398 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 399 MODULE_DESCRIPTION("Generic cpufreq driver");
 400 MODULE_LICENSE("GPL");