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  * The OPP code in function set_target() is reused from
   8  * drivers/cpufreq/omap-cpufreq.c
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14
  15 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
  16
  17 #include <linux/clk.h>
  18 #include <linux/cpu.h>
  19 #include <linux/cpu_cooling.h>
  20 #include <linux/cpufreq.h>
  21 #include <linux/cpufreq-dt.h>
  22 #include <linux/cpumask.h>
  23 #include <linux/err.h>
  24 #include <linux/module.h>
  25 #include <linux/of.h>
  26 #include <linux/pm_opp.h>
  27 #include <linux/platform_device.h>
  28 #include <linux/regulator/consumer.h>
  29 #include <linux/slab.h>
  30 #include <linux/thermal.h>
  31
  32 struct private_data {
  33         struct device *cpu_dev;
  34         struct thermal_cooling_device *cdev;
  35         const char *reg_name;
  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 private_data *priv;
 149         struct device *cpu_dev;
 150         struct clk *cpu_clk;
 151         struct dev_pm_opp *suspend_opp;
 152         unsigned int transition_latency;
 153         bool opp_v1 = 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                 /*
 174                  * operating-points-v2 not supported, fallback to old method of
 175                  * finding shared-OPPs for backward compatibility.
 176                  */
 177                 if (ret == -ENOENT)
 178                         opp_v1 = true;
 179                 else
 180                         goto out_put_clk;
 181         }
 182
 183         /*
 184          * OPP layer will be taking care of regulators now, but it needs to know
 185          * the name of the regulator first.
 186          */
 187         name = find_supply_name(cpu_dev);
 188         if (name) {
 189                 ret = dev_pm_opp_set_regulator(cpu_dev, name);
 190                 if (ret) {
 191                         dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n",
 192                                 policy->cpu, ret);
 193                         goto out_put_clk;
 194                 }
 195         }
 196
 197         /*
 198          * Initialize OPP tables for all policy->cpus. They will be shared by
 199          * all CPUs which have marked their CPUs shared with OPP bindings.
 200          *
 201          * For platforms not using operating-points-v2 bindings, we do this
 202          * before updating policy->cpus. Otherwise, we will end up creating
 203          * duplicate OPPs for policy->cpus.
 204          *
 205          * OPPs might be populated at runtime, don't check for error here
 206          */
 207         dev_pm_opp_of_cpumask_add_table(policy->cpus);
 208
 209         /*
 210          * But we need OPP table to function so if it is not there let's
 211          * give platform code chance to provide it for us.
 212          */
 213         ret = dev_pm_opp_get_opp_count(cpu_dev);
 214         if (ret <= 0) {
 215                 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
 216                 ret = -EPROBE_DEFER;
 217                 goto out_free_opp;
 218         }
 219
 220         if (opp_v1) {
 221                 struct cpufreq_dt_platform_data *pd = cpufreq_get_driver_data();
 222
 223                 if (!pd || !pd->independent_clocks)
 224                         cpumask_setall(policy->cpus);
 225
 226                 /*
 227                  * OPP tables are initialized only for policy->cpu, do it for
 228                  * others as well.
 229                  */
 230                 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
 231                 if (ret)
 232                         dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 233                                 __func__, ret);
 234         }
 235
 236         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 237         if (!priv) {
 238                 ret = -ENOMEM;
 239                 goto out_free_opp;
 240         }
 241
 242         priv->reg_name = name;
 243
 244         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 245         if (ret) {
 246                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 247                 goto out_free_priv;
 248         }
 249
 250         priv->cpu_dev = cpu_dev;
 251         policy->driver_data = priv;
 252         policy->clk = cpu_clk;
 253
 254         rcu_read_lock();
 255         suspend_opp = dev_pm_opp_get_suspend_opp(cpu_dev);
 256         if (suspend_opp)
 257                 policy->suspend_freq = dev_pm_opp_get_freq(suspend_opp) / 1000;
 258         rcu_read_unlock();
 259
 260         ret = cpufreq_table_validate_and_show(policy, freq_table);
 261         if (ret) {
 262                 dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
 263                         ret);
 264                 goto out_free_cpufreq_table;
 265         }
 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
 282         return 0;
 283
 284 out_free_cpufreq_table:
 285         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 286 out_free_priv:
 287         kfree(priv);
 288 out_free_opp:
 289         dev_pm_opp_of_cpumask_remove_table(policy->cpus);
 290         if (name)
 291                 dev_pm_opp_put_regulator(cpu_dev);
 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         dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
 305         if (priv->reg_name)
 306                 dev_pm_opp_put_regulator(priv->cpu_dev);
 307
 308         clk_put(policy->clk);
 309         kfree(priv);
 310
 311         return 0;
 312 }
 313
 314 static void cpufreq_ready(struct cpufreq_policy *policy)
 315 {
 316         struct private_data *priv = policy->driver_data;
 317         struct device_node *np = of_node_get(priv->cpu_dev->of_node);
 318
 319         if (WARN_ON(!np))
 320                 return;
 321
 322         /*
 323          * For now, just loading the cooling device;
 324          * thermal DT code takes care of matching them.
 325          */
 326         if (of_find_property(np, "#cooling-cells", NULL)) {
 327                 u32 power_coefficient = 0;
 328
 329                 of_property_read_u32(np, "dynamic-power-coefficient",
 330                                      &power_coefficient);
 331
 332                 priv->cdev = of_cpufreq_power_cooling_register(np,
 333                                 policy->related_cpus, power_coefficient, NULL);
 334                 if (IS_ERR(priv->cdev)) {
 335                         dev_err(priv->cpu_dev,
 336                                 "running cpufreq without cooling device: %ld\n",
 337                                 PTR_ERR(priv->cdev));
 338
 339                         priv->cdev = NULL;
 340                 }
 341         }
 342
 343         of_node_put(np);
 344 }
 345
 346 static struct cpufreq_driver dt_cpufreq_driver = {
 347         .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 348         .verify = cpufreq_generic_frequency_table_verify,
 349         .target_index = set_target,
 350         .get = cpufreq_generic_get,
 351         .init = cpufreq_init,
 352         .exit = cpufreq_exit,
 353         .ready = cpufreq_ready,
 354         .name = "cpufreq-dt",
 355         .attr = cpufreq_dt_attr,
 356         .suspend = cpufreq_generic_suspend,
 357 };
 358
 359 static int dt_cpufreq_probe(struct platform_device *pdev)
 360 {
 361         int ret;
 362
 363         /*
 364          * All per-cluster (CPUs sharing clock/voltages) initialization is done
 365          * from ->init(). In probe(), we just need to make sure that clk and
 366          * regulators are available. Else defer probe and retry.
 367          *
 368          * FIXME: Is checking this only for CPU0 sufficient ?
 369          */
 370         ret = resources_available();
 371         if (ret)
 372                 return ret;
 373
 374         dt_cpufreq_driver.driver_data = dev_get_platdata(&pdev->dev);
 375
 376         ret = cpufreq_register_driver(&dt_cpufreq_driver);
 377         if (ret)
 378                 dev_err(&pdev->dev, "failed register driver: %d\n", ret);
 379
 380         return ret;
 381 }
 382
 383 static int dt_cpufreq_remove(struct platform_device *pdev)
 384 {
 385         cpufreq_unregister_driver(&dt_cpufreq_driver);
 386         return 0;
 387 }
 388
 389 static struct platform_driver dt_cpufreq_platdrv = {
 390         .driver = {
 391                 .name   = "cpufreq-dt",
 392         },
 393         .probe          = dt_cpufreq_probe,
 394         .remove         = dt_cpufreq_remove,
 395 };
 396 module_platform_driver(dt_cpufreq_platdrv);
 397
 398 MODULE_ALIAS("platform:cpufreq-dt");
 399 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 400 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 401 MODULE_DESCRIPTION("Generic cpufreq driver");
 402 MODULE_LICENSE("GPL");