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