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