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