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 regulator *cpu_reg;
  35         struct thermal_cooling_device *cdev;
  36         const char *reg_name;
  37 };
  38
  39 static struct freq_attr *cpufreq_dt_attr[] = {
  40         &cpufreq_freq_attr_scaling_available_freqs,
  41         NULL,   /* Extra space for boost-attr if required */
  42         NULL,
  43 };
  44
  45 static int set_target(struct cpufreq_policy *policy, unsigned int index)
  46 {
  47         struct private_data *priv = policy->driver_data;
  48
  49         return dev_pm_opp_set_rate(priv->cpu_dev,
  50                                    policy->freq_table[index].frequency * 1000);
  51 }
  52
  53 /*
  54  * An earlier version of opp-v1 bindings used to name the regulator
  55  * "cpu0-supply", we still need to handle that for backwards compatibility.
  56  */
  57 static const char *find_supply_name(struct device *dev)
  58 {
  59         struct device_node *np;
  60         struct property *pp;
  61         int cpu = dev->id;
  62         const char *name = NULL;
  63
  64         np = of_node_get(dev->of_node);
  65
  66         /* This must be valid for sure */
  67         if (WARN_ON(!np))
  68                 return NULL;
  69
  70         /* Try "cpu0" for older DTs */
  71         if (!cpu) {
  72                 pp = of_find_property(np, "cpu0-supply", NULL);
  73                 if (pp) {
  74                         name = "cpu0";
  75                         goto node_put;
  76                 }
  77         }
  78
  79         pp = of_find_property(np, "cpu-supply", NULL);
  80         if (pp) {
  81                 name = "cpu";
  82                 goto node_put;
  83         }
  84
  85         dev_dbg(dev, "no regulator for cpu%d\n", cpu);
  86 node_put:
  87         of_node_put(np);
  88         return name;
  89 }
  90
  91 static int allocate_resources(int cpu, struct device **cdev,
  92                               struct regulator **creg, struct clk **cclk)
  93 {
  94         struct device *cpu_dev;
  95         struct regulator *cpu_reg;
  96         struct clk *cpu_clk;
  97         int ret = 0;
  98         char *reg_cpu0 = "cpu0", *reg_cpu = "cpu", *reg;
  99
 100         cpu_dev = get_cpu_device(cpu);
 101         if (!cpu_dev) {
 102                 pr_err("failed to get cpu%d device\n", cpu);
 103                 return -ENODEV;
 104         }
 105
 106         /* Try "cpu0" for older DTs */
 107         if (!cpu)
 108                 reg = reg_cpu0;
 109         else
 110                 reg = reg_cpu;
 111
 112 try_again:
 113         cpu_reg = regulator_get_optional(cpu_dev, reg);
 114         ret = PTR_ERR_OR_ZERO(cpu_reg);
 115         if (ret) {
 116                 /*
 117                  * If cpu's regulator supply node is present, but regulator is
 118                  * not yet registered, we should try defering probe.
 119                  */
 120                 if (ret == -EPROBE_DEFER) {
 121                         dev_dbg(cpu_dev, "cpu%d regulator not ready, retry\n",
 122                                 cpu);
 123                         return ret;
 124                 }
 125
 126                 /* Try with "cpu-supply" */
 127                 if (reg == reg_cpu0) {
 128                         reg = reg_cpu;
 129                         goto try_again;
 130                 }
 131
 132                 dev_dbg(cpu_dev, "no regulator for cpu%d: %d\n", cpu, ret);
 133         }
 134
 135         cpu_clk = clk_get(cpu_dev, NULL);
 136         ret = PTR_ERR_OR_ZERO(cpu_clk);
 137         if (ret) {
 138                 /* put regulator */
 139                 if (!IS_ERR(cpu_reg))
 140                         regulator_put(cpu_reg);
 141
 142                 /*
 143                  * If cpu's clk node is present, but clock is not yet
 144                  * registered, we should try defering probe.
 145                  */
 146                 if (ret == -EPROBE_DEFER)
 147                         dev_dbg(cpu_dev, "cpu%d clock not ready, retry\n", cpu);
 148                 else
 149                         dev_err(cpu_dev, "failed to get cpu%d clock: %d\n", cpu,
 150                                 ret);
 151         } else {
 152                 *cdev = cpu_dev;
 153                 *creg = cpu_reg;
 154                 *cclk = cpu_clk;
 155         }
 156
 157         return ret;
 158 }
 159
 160 static int cpufreq_init(struct cpufreq_policy *policy)
 161 {
 162         struct cpufreq_frequency_table *freq_table;
 163         struct private_data *priv;
 164         struct device *cpu_dev;
 165         struct regulator *cpu_reg;
 166         struct clk *cpu_clk;
 167         struct dev_pm_opp *suspend_opp;
 168         unsigned int transition_latency;
 169         bool opp_v1 = false;
 170         const char *name;
 171         int ret;
 172
 173         ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
 174         if (ret) {
 175                 pr_err("%s: Failed to allocate resources: %d\n", __func__, ret);
 176                 return ret;
 177         }
 178
 179         /* Get OPP-sharing information from "operating-points-v2" bindings */
 180         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus);
 181         if (ret) {
 182                 /*
 183                  * operating-points-v2 not supported, fallback to old method of
 184                  * finding shared-OPPs for backward compatibility.
 185                  */
 186                 if (ret == -ENOENT)
 187                         opp_v1 = true;
 188                 else
 189                         goto out_put_reg_clk;
 190         }
 191
 192         /*
 193          * OPP layer will be taking care of regulators now, but it needs to know
 194          * the name of the regulator first.
 195          */
 196         name = find_supply_name(cpu_dev);
 197         if (name) {
 198                 ret = dev_pm_opp_set_regulator(cpu_dev, name);
 199                 if (ret) {
 200                         dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n",
 201                                 policy->cpu, ret);
 202                         goto out_put_reg_clk;
 203                 }
 204         }
 205
 206         /*
 207          * Initialize OPP tables for all policy->cpus. They will be shared by
 208          * all CPUs which have marked their CPUs shared with OPP bindings.
 209          *
 210          * For platforms not using operating-points-v2 bindings, we do this
 211          * before updating policy->cpus. Otherwise, we will end up creating
 212          * duplicate OPPs for policy->cpus.
 213          *
 214          * OPPs might be populated at runtime, don't check for error here
 215          */
 216         dev_pm_opp_of_cpumask_add_table(policy->cpus);
 217
 218         /*
 219          * But we need OPP table to function so if it is not there let's
 220          * give platform code chance to provide it for us.
 221          */
 222         ret = dev_pm_opp_get_opp_count(cpu_dev);
 223         if (ret <= 0) {
 224                 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
 225                 ret = -EPROBE_DEFER;
 226                 goto out_free_opp;
 227         }
 228
 229         if (opp_v1) {
 230                 struct cpufreq_dt_platform_data *pd = cpufreq_get_driver_data();
 231
 232                 if (!pd || !pd->independent_clocks)
 233                         cpumask_setall(policy->cpus);
 234
 235                 /*
 236                  * OPP tables are initialized only for policy->cpu, do it for
 237                  * others as well.
 238                  */
 239                 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
 240                 if (ret)
 241                         dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 242                                 __func__, ret);
 243         }
 244
 245         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 246         if (!priv) {
 247                 ret = -ENOMEM;
 248                 goto out_free_opp;
 249         }
 250
 251         priv->reg_name = name;
 252
 253         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 254         if (ret) {
 255                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 256                 goto out_free_priv;
 257         }
 258
 259         priv->cpu_dev = cpu_dev;
 260         priv->cpu_reg = cpu_reg;
 261         policy->driver_data = priv;
 262
 263         policy->clk = cpu_clk;
 264
 265         rcu_read_lock();
 266         suspend_opp = dev_pm_opp_get_suspend_opp(cpu_dev);
 267         if (suspend_opp)
 268                 policy->suspend_freq = dev_pm_opp_get_freq(suspend_opp) / 1000;
 269         rcu_read_unlock();
 270
 271         ret = cpufreq_table_validate_and_show(policy, freq_table);
 272         if (ret) {
 273                 dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
 274                         ret);
 275                 goto out_free_cpufreq_table;
 276         }
 277
 278         /* Support turbo/boost mode */
 279         if (policy_has_boost_freq(policy)) {
 280                 /* This gets disabled by core on driver unregister */
 281                 ret = cpufreq_enable_boost_support();
 282                 if (ret)
 283                         goto out_free_cpufreq_table;
 284                 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
 285         }
 286
 287         transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
 288         if (!transition_latency)
 289                 transition_latency = CPUFREQ_ETERNAL;
 290
 291         policy->cpuinfo.transition_latency = transition_latency;
 292
 293         return 0;
 294
 295 out_free_cpufreq_table:
 296         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 297 out_free_priv:
 298         kfree(priv);
 299 out_free_opp:
 300         dev_pm_opp_of_cpumask_remove_table(policy->cpus);
 301         if (name)
 302                 dev_pm_opp_put_regulator(cpu_dev);
 303 out_put_reg_clk:
 304         clk_put(cpu_clk);
 305         if (!IS_ERR(cpu_reg))
 306                 regulator_put(cpu_reg);
 307
 308         return ret;
 309 }
 310
 311 static int cpufreq_exit(struct cpufreq_policy *policy)
 312 {
 313         struct private_data *priv = policy->driver_data;
 314
 315         cpufreq_cooling_unregister(priv->cdev);
 316         dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
 317         dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
 318         if (priv->reg_name)
 319                 dev_pm_opp_put_regulator(priv->cpu_dev);
 320
 321         clk_put(policy->clk);
 322         if (!IS_ERR(priv->cpu_reg))
 323                 regulator_put(priv->cpu_reg);
 324         kfree(priv);
 325
 326         return 0;
 327 }
 328
 329 static void cpufreq_ready(struct cpufreq_policy *policy)
 330 {
 331         struct private_data *priv = policy->driver_data;
 332         struct device_node *np = of_node_get(priv->cpu_dev->of_node);
 333
 334         if (WARN_ON(!np))
 335                 return;
 336
 337         /*
 338          * For now, just loading the cooling device;
 339          * thermal DT code takes care of matching them.
 340          */
 341         if (of_find_property(np, "#cooling-cells", NULL)) {
 342                 u32 power_coefficient = 0;
 343
 344                 of_property_read_u32(np, "dynamic-power-coefficient",
 345                                      &power_coefficient);
 346
 347                 priv->cdev = of_cpufreq_power_cooling_register(np,
 348                                 policy->related_cpus, power_coefficient, NULL);
 349                 if (IS_ERR(priv->cdev)) {
 350                         dev_err(priv->cpu_dev,
 351                                 "running cpufreq without cooling device: %ld\n",
 352                                 PTR_ERR(priv->cdev));
 353
 354                         priv->cdev = NULL;
 355                 }
 356         }
 357
 358         of_node_put(np);
 359 }
 360
 361 static struct cpufreq_driver dt_cpufreq_driver = {
 362         .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 363         .verify = cpufreq_generic_frequency_table_verify,
 364         .target_index = set_target,
 365         .get = cpufreq_generic_get,
 366         .init = cpufreq_init,
 367         .exit = cpufreq_exit,
 368         .ready = cpufreq_ready,
 369         .name = "cpufreq-dt",
 370         .attr = cpufreq_dt_attr,
 371         .suspend = cpufreq_generic_suspend,
 372 };
 373
 374 static int dt_cpufreq_probe(struct platform_device *pdev)
 375 {
 376         struct device *cpu_dev;
 377         struct regulator *cpu_reg;
 378         struct clk *cpu_clk;
 379         int ret;
 380
 381         /*
 382          * All per-cluster (CPUs sharing clock/voltages) initialization is done
 383          * from ->init(). In probe(), we just need to make sure that clk and
 384          * regulators are available. Else defer probe and retry.
 385          *
 386          * FIXME: Is checking this only for CPU0 sufficient ?
 387          */
 388         ret = allocate_resources(0, &cpu_dev, &cpu_reg, &cpu_clk);
 389         if (ret)
 390                 return ret;
 391
 392         clk_put(cpu_clk);
 393         if (!IS_ERR(cpu_reg))
 394                 regulator_put(cpu_reg);
 395
 396         dt_cpufreq_driver.driver_data = dev_get_platdata(&pdev->dev);
 397
 398         ret = cpufreq_register_driver(&dt_cpufreq_driver);
 399         if (ret)
 400                 dev_err(cpu_dev, "failed register driver: %d\n", ret);
 401
 402         return ret;
 403 }
 404
 405 static int dt_cpufreq_remove(struct platform_device *pdev)
 406 {
 407         cpufreq_unregister_driver(&dt_cpufreq_driver);
 408         return 0;
 409 }
 410
 411 static struct platform_driver dt_cpufreq_platdrv = {
 412         .driver = {
 413                 .name   = "cpufreq-dt",
 414         },
 415         .probe          = dt_cpufreq_probe,
 416         .remove         = dt_cpufreq_remove,
 417 };
 418 module_platform_driver(dt_cpufreq_platdrv);
 419
 420 MODULE_ALIAS("platform:cpufreq-dt");
 421 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 422 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 423 MODULE_DESCRIPTION("Generic cpufreq driver");
 424 MODULE_LICENSE("GPL");