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/cpufreq.h>
  17 #include <linux/cpumask.h>
  18 #include <linux/err.h>
  19 #include <linux/module.h>
  20 #include <linux/of.h>
  21 #include <linux/pm_opp.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/regulator/consumer.h>
  24 #include <linux/slab.h>
  25 #include <linux/thermal.h>
  26
  27 #include "cpufreq-dt.h"
  28
  29 struct private_data {
  30         struct opp_table *opp_table;
  31         struct device *cpu_dev;
  32         const char *reg_name;
  33         bool have_static_opps;
  34 };
  35
  36 static struct freq_attr *cpufreq_dt_attr[] = {
  37         &cpufreq_freq_attr_scaling_available_freqs,
  38         NULL,   /* Extra space for boost-attr if required */
  39         NULL,
  40 };
  41
  42 static int set_target(struct cpufreq_policy *policy, unsigned int index)
  43 {
  44         struct private_data *priv = policy->driver_data;
  45         unsigned long freq = policy->freq_table[index].frequency;
  46         int ret;
  47
  48         ret = dev_pm_opp_set_rate(priv->cpu_dev, freq * 1000);
  49
  50         if (!ret) {
  51                 arch_set_freq_scale(policy->related_cpus, freq,
  52                                     policy->cpuinfo.max_freq);
  53         }
  54
  55         return ret;
  56 }
  57
  58 /*
  59  * An earlier version of opp-v1 bindings used to name the regulator
  60  * "cpu0-supply", we still need to handle that for backwards compatibility.
  61  */
  62 static const char *find_supply_name(struct device *dev)
  63 {
  64         struct device_node *np;
  65         struct property *pp;
  66         int cpu = dev->id;
  67         const char *name = NULL;
  68
  69         np = of_node_get(dev->of_node);
  70
  71         /* This must be valid for sure */
  72         if (WARN_ON(!np))
  73                 return NULL;
  74
  75         /* Try "cpu0" for older DTs */
  76         if (!cpu) {
  77                 pp = of_find_property(np, "cpu0-supply", NULL);
  78                 if (pp) {
  79                         name = "cpu0";
  80                         goto node_put;
  81                 }
  82         }
  83
  84         pp = of_find_property(np, "cpu-supply", NULL);
  85         if (pp) {
  86                 name = "cpu";
  87                 goto node_put;
  88         }
  89
  90         dev_dbg(dev, "no regulator for cpu%d\n", cpu);
  91 node_put:
  92         of_node_put(np);
  93         return name;
  94 }
  95
  96 static int resources_available(void)
  97 {
  98         struct device *cpu_dev;
  99         struct regulator *cpu_reg;
 100         struct clk *cpu_clk;
 101         int ret = 0;
 102         const char *name;
 103
 104         cpu_dev = get_cpu_device(0);
 105         if (!cpu_dev) {
 106                 pr_err("failed to get cpu0 device\n");
 107                 return -ENODEV;
 108         }
 109
 110         cpu_clk = clk_get(cpu_dev, NULL);
 111         ret = PTR_ERR_OR_ZERO(cpu_clk);
 112         if (ret) {
 113                 /*
 114                  * If cpu's clk node is present, but clock is not yet
 115                  * registered, we should try defering probe.
 116                  */
 117                 if (ret == -EPROBE_DEFER)
 118                         dev_dbg(cpu_dev, "clock not ready, retry\n");
 119                 else
 120                         dev_err(cpu_dev, "failed to get clock: %d\n", ret);
 121
 122                 return ret;
 123         }
 124
 125         clk_put(cpu_clk);
 126
 127         name = find_supply_name(cpu_dev);
 128         /* Platform doesn't require regulator */
 129         if (!name)
 130                 return 0;
 131
 132         cpu_reg = regulator_get_optional(cpu_dev, name);
 133         ret = PTR_ERR_OR_ZERO(cpu_reg);
 134         if (ret) {
 135                 /*
 136                  * If cpu's regulator supply node is present, but regulator is
 137                  * not yet registered, we should try defering probe.
 138                  */
 139                 if (ret == -EPROBE_DEFER)
 140                         dev_dbg(cpu_dev, "cpu0 regulator not ready, retry\n");
 141                 else
 142                         dev_dbg(cpu_dev, "no regulator for cpu0: %d\n", ret);
 143
 144                 return ret;
 145         }
 146
 147         regulator_put(cpu_reg);
 148         return 0;
 149 }
 150
 151 static int cpufreq_init(struct cpufreq_policy *policy)
 152 {
 153         struct cpufreq_frequency_table *freq_table;
 154         struct opp_table *opp_table = NULL;
 155         struct private_data *priv;
 156         struct device *cpu_dev;
 157         struct clk *cpu_clk;
 158         unsigned int transition_latency;
 159         bool fallback = false;
 160         const char *name;
 161         int ret;
 162
 163         cpu_dev = get_cpu_device(policy->cpu);
 164         if (!cpu_dev) {
 165                 pr_err("failed to get cpu%d device\n", policy->cpu);
 166                 return -ENODEV;
 167         }
 168
 169         cpu_clk = clk_get(cpu_dev, NULL);
 170         if (IS_ERR(cpu_clk)) {
 171                 ret = PTR_ERR(cpu_clk);
 172                 dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret);
 173                 return ret;
 174         }
 175
 176         /* Get OPP-sharing information from "operating-points-v2" bindings */
 177         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus);
 178         if (ret) {
 179                 if (ret != -ENOENT)
 180                         goto out_put_clk;
 181
 182                 /*
 183                  * operating-points-v2 not supported, fallback to old method of
 184                  * finding shared-OPPs for backward compatibility if the
 185                  * platform hasn't set sharing CPUs.
 186                  */
 187                 if (dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus))
 188                         fallback = true;
 189         }
 190
 191         /*
 192          * OPP layer will be taking care of regulators now, but it needs to know
 193          * the name of the regulator first.
 194          */
 195         name = find_supply_name(cpu_dev);
 196         if (name) {
 197                 opp_table = dev_pm_opp_set_regulators(cpu_dev, &name, 1);
 198                 if (IS_ERR(opp_table)) {
 199                         ret = PTR_ERR(opp_table);
 200                         dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n",
 201                                 policy->cpu, ret);
 202                         goto out_put_clk;
 203                 }
 204         }
 205
 206         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 207         if (!priv) {
 208                 ret = -ENOMEM;
 209                 goto out_put_regulator;
 210         }
 211
 212         priv->reg_name = name;
 213         priv->opp_table = opp_table;
 214
 215         /*
 216          * Initialize OPP tables for all policy->cpus. They will be shared by
 217          * all CPUs which have marked their CPUs shared with OPP bindings.
 218          *
 219          * For platforms not using operating-points-v2 bindings, we do this
 220          * before updating policy->cpus. Otherwise, we will end up creating
 221          * duplicate OPPs for policy->cpus.
 222          *
 223          * OPPs might be populated at runtime, don't check for error here
 224          */
 225         if (!dev_pm_opp_of_cpumask_add_table(policy->cpus))
 226                 priv->have_static_opps = true;
 227
 228         /*
 229          * But we need OPP table to function so if it is not there let's
 230          * give platform code chance to provide it for us.
 231          */
 232         ret = dev_pm_opp_get_opp_count(cpu_dev);
 233         if (ret <= 0) {
 234                 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
 235                 ret = -EPROBE_DEFER;
 236                 goto out_free_opp;
 237         }
 238
 239         if (fallback) {
 240                 cpumask_setall(policy->cpus);
 241
 242                 /*
 243                  * OPP tables are initialized only for policy->cpu, do it for
 244                  * others as well.
 245                  */
 246                 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
 247                 if (ret)
 248                         dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 249                                 __func__, ret);
 250         }
 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_opp;
 256         }
 257
 258         priv->cpu_dev = cpu_dev;
 259         policy->driver_data = priv;
 260         policy->clk = cpu_clk;
 261         policy->freq_table = freq_table;
 262
 263         policy->suspend_freq = dev_pm_opp_get_suspend_opp_freq(cpu_dev) / 1000;
 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_online(struct cpufreq_policy *policy)
 299 {
 300         /* We did light-weight tear down earlier, nothing to do here */
 301         return 0;
 302 }
 303
 304 static int cpufreq_offline(struct cpufreq_policy *policy)
 305 {
 306         /*
 307          * Preserve policy->driver_data and don't free resources on light-weight
 308          * tear down.
 309          */
 310         return 0;
 311 }
 312
 313 static int cpufreq_exit(struct cpufreq_policy *policy)
 314 {
 315         struct private_data *priv = policy->driver_data;
 316
 317         dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
 318         if (priv->have_static_opps)
 319                 dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
 320         if (priv->reg_name)
 321                 dev_pm_opp_put_regulators(priv->opp_table);
 322
 323         clk_put(policy->clk);
 324         kfree(priv);
 325
 326         return 0;
 327 }
 328
 329 static struct cpufreq_driver dt_cpufreq_driver = {
 330         .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK |
 331                  CPUFREQ_IS_COOLING_DEV,
 332         .verify = cpufreq_generic_frequency_table_verify,
 333         .target_index = set_target,
 334         .get = cpufreq_generic_get,
 335         .init = cpufreq_init,
 336         .exit = cpufreq_exit,
 337         .online = cpufreq_online,
 338         .offline = cpufreq_offline,
 339         .name = "cpufreq-dt",
 340         .attr = cpufreq_dt_attr,
 341         .suspend = cpufreq_generic_suspend,
 342 };
 343
 344 static int dt_cpufreq_probe(struct platform_device *pdev)
 345 {
 346         struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev);
 347         int ret;
 348
 349         /*
 350          * All per-cluster (CPUs sharing clock/voltages) initialization is done
 351          * from ->init(). In probe(), we just need to make sure that clk and
 352          * regulators are available. Else defer probe and retry.
 353          *
 354          * FIXME: Is checking this only for CPU0 sufficient ?
 355          */
 356         ret = resources_available();
 357         if (ret)
 358                 return ret;
 359
 360         if (data) {
 361                 if (data->have_governor_per_policy)
 362                         dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY;
 363
 364                 dt_cpufreq_driver.resume = data->resume;
 365                 if (data->suspend)
 366                         dt_cpufreq_driver.suspend = data->suspend;
 367         }
 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");