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