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/cpufreq-dt.h>
  19 #include <linux/cpumask.h>
  20 #include <linux/err.h>
  21 #include <linux/module.h>
  22 #include <linux/of.h>
  23 #include <linux/pm_opp.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/regulator/consumer.h>
  26 #include <linux/slab.h>
  27 #include <linux/thermal.h>
  28
  29 struct private_data {
  30         struct device *cpu_dev;
  31         struct thermal_cooling_device *cdev;
  32         const char *reg_name;
  33 };
  34
  35 static struct freq_attr *cpufreq_dt_attr[] = {
  36         &cpufreq_freq_attr_scaling_available_freqs,
  37         NULL,   /* Extra space for boost-attr if required */
  38         NULL,
  39 };
  40
  41 static int set_target(struct cpufreq_policy *policy, unsigned int index)
  42 {
  43         struct private_data *priv = policy->driver_data;
  44
  45         return dev_pm_opp_set_rate(priv->cpu_dev,
  46                                    policy->freq_table[index].frequency * 1000);
  47 }
  48
  49 /*
  50  * An earlier version of opp-v1 bindings used to name the regulator
  51  * "cpu0-supply", we still need to handle that for backwards compatibility.
  52  */
  53 static const char *find_supply_name(struct device *dev)
  54 {
  55         struct device_node *np;
  56         struct property *pp;
  57         int cpu = dev->id;
  58         const char *name = NULL;
  59
  60         np = of_node_get(dev->of_node);
  61
  62         /* This must be valid for sure */
  63         if (WARN_ON(!np))
  64                 return NULL;
  65
  66         /* Try "cpu0" for older DTs */
  67         if (!cpu) {
  68                 pp = of_find_property(np, "cpu0-supply", NULL);
  69                 if (pp) {
  70                         name = "cpu0";
  71                         goto node_put;
  72                 }
  73         }
  74
  75         pp = of_find_property(np, "cpu-supply", NULL);
  76         if (pp) {
  77                 name = "cpu";
  78                 goto node_put;
  79         }
  80
  81         dev_dbg(dev, "no regulator for cpu%d\n", cpu);
  82 node_put:
  83         of_node_put(np);
  84         return name;
  85 }
  86
  87 static int resources_available(void)
  88 {
  89         struct device *cpu_dev;
  90         struct regulator *cpu_reg;
  91         struct clk *cpu_clk;
  92         int ret = 0;
  93         const char *name;
  94
  95         cpu_dev = get_cpu_device(0);
  96         if (!cpu_dev) {
  97                 pr_err("failed to get cpu0 device\n");
  98                 return -ENODEV;
  99         }
 100
 101         cpu_clk = clk_get(cpu_dev, NULL);
 102         ret = PTR_ERR_OR_ZERO(cpu_clk);
 103         if (ret) {
 104                 /*
 105                  * If cpu's clk node is present, but clock is not yet
 106                  * registered, we should try defering probe.
 107                  */
 108                 if (ret == -EPROBE_DEFER)
 109                         dev_dbg(cpu_dev, "clock not ready, retry\n");
 110                 else
 111                         dev_err(cpu_dev, "failed to get clock: %d\n", ret);
 112
 113                 return ret;
 114         }
 115
 116         clk_put(cpu_clk);
 117
 118         name = find_supply_name(cpu_dev);
 119         /* Platform doesn't require regulator */
 120         if (!name)
 121                 return 0;
 122
 123         cpu_reg = regulator_get_optional(cpu_dev, name);
 124         ret = PTR_ERR_OR_ZERO(cpu_reg);
 125         if (ret) {
 126                 /*
 127                  * If cpu's regulator supply node is present, but regulator is
 128                  * not yet registered, we should try defering probe.
 129                  */
 130                 if (ret == -EPROBE_DEFER)
 131                         dev_dbg(cpu_dev, "cpu0 regulator not ready, retry\n");
 132                 else
 133                         dev_dbg(cpu_dev, "no regulator for cpu0: %d\n", ret);
 134
 135                 return ret;
 136         }
 137
 138         regulator_put(cpu_reg);
 139         return 0;
 140 }
 141
 142 static int cpufreq_init(struct cpufreq_policy *policy)
 143 {
 144         struct cpufreq_frequency_table *freq_table;
 145         struct private_data *priv;
 146         struct device *cpu_dev;
 147         struct clk *cpu_clk;
 148         struct dev_pm_opp *suspend_opp;
 149         unsigned int transition_latency;
 150         bool opp_v1 = false;
 151         const char *name;
 152         int ret;
 153
 154         cpu_dev = get_cpu_device(policy->cpu);
 155         if (!cpu_dev) {
 156                 pr_err("failed to get cpu%d device\n", policy->cpu);
 157                 return -ENODEV;
 158         }
 159
 160         cpu_clk = clk_get(cpu_dev, NULL);
 161         if (IS_ERR(cpu_clk)) {
 162                 ret = PTR_ERR(cpu_clk);
 163                 dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret);
 164                 return ret;
 165         }
 166
 167         /* Get OPP-sharing information from "operating-points-v2" bindings */
 168         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus);
 169         if (ret) {
 170                 /*
 171                  * operating-points-v2 not supported, fallback to old method of
 172                  * finding shared-OPPs for backward compatibility.
 173                  */
 174                 if (ret == -ENOENT)
 175                         opp_v1 = true;
 176                 else
 177                         goto out_put_clk;
 178         }
 179
 180         /*
 181          * OPP layer will be taking care of regulators now, but it needs to know
 182          * the name of the regulator first.
 183          */
 184         name = find_supply_name(cpu_dev);
 185         if (name) {
 186                 ret = dev_pm_opp_set_regulator(cpu_dev, name);
 187                 if (ret) {
 188                         dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n",
 189                                 policy->cpu, ret);
 190                         goto out_put_clk;
 191                 }
 192         }
 193
 194         /*
 195          * Initialize OPP tables for all policy->cpus. They will be shared by
 196          * all CPUs which have marked their CPUs shared with OPP bindings.
 197          *
 198          * For platforms not using operating-points-v2 bindings, we do this
 199          * before updating policy->cpus. Otherwise, we will end up creating
 200          * duplicate OPPs for policy->cpus.
 201          *
 202          * OPPs might be populated at runtime, don't check for error here
 203          */
 204         dev_pm_opp_of_cpumask_add_table(policy->cpus);
 205
 206         /*
 207          * But we need OPP table to function so if it is not there let's
 208          * give platform code chance to provide it for us.
 209          */
 210         ret = dev_pm_opp_get_opp_count(cpu_dev);
 211         if (ret <= 0) {
 212                 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
 213                 ret = -EPROBE_DEFER;
 214                 goto out_free_opp;
 215         }
 216
 217         if (opp_v1) {
 218                 struct cpufreq_dt_platform_data *pd = cpufreq_get_driver_data();
 219
 220                 if (!pd || !pd->independent_clocks)
 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         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         dt_cpufreq_driver.driver_data = dev_get_platdata(&pdev->dev);
 372
 373         ret = cpufreq_register_driver(&dt_cpufreq_driver);
 374         if (ret)
 375                 dev_err(&pdev->dev, "failed register driver: %d\n", ret);
 376
 377         return ret;
 378 }
 379
 380 static int dt_cpufreq_remove(struct platform_device *pdev)
 381 {
 382         cpufreq_unregister_driver(&dt_cpufreq_driver);
 383         return 0;
 384 }
 385
 386 static struct platform_driver dt_cpufreq_platdrv = {
 387         .driver = {
 388                 .name   = "cpufreq-dt",
 389         },
 390         .probe          = dt_cpufreq_probe,
 391         .remove         = dt_cpufreq_remove,
 392 };
 393 module_platform_driver(dt_cpufreq_platdrv);
 394
 395 MODULE_ALIAS("platform:cpufreq-dt");
 396 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 397 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 398 MODULE_DESCRIPTION("Generic cpufreq driver");
 399 MODULE_LICENSE("GPL");