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