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         unsigned int voltage_tolerance; /* in percentage */
  37         const char *reg_name;
  38 };
  39
  40 static struct freq_attr *cpufreq_dt_attr[] = {
  41         &cpufreq_freq_attr_scaling_available_freqs,
  42         NULL,   /* Extra space for boost-attr if required */
  43         NULL,
  44 };
  45
  46 static int set_target(struct cpufreq_policy *policy, unsigned int index)
  47 {
  48         struct private_data *priv = policy->driver_data;
  49
  50         return dev_pm_opp_set_rate(priv->cpu_dev,
  51                                    policy->freq_table[index].frequency * 1000);
  52 }
  53
  54 /*
  55  * An earlier version of opp-v1 bindings used to name the regulator
  56  * "cpu0-supply", we still need to handle that for backwards compatibility.
  57  */
  58 static const char *find_supply_name(struct device *dev, struct device_node *np)
  59 {
  60         struct property *pp;
  61         int cpu = dev->id;
  62
  63         /* Try "cpu0" for older DTs */
  64         if (!cpu) {
  65                 pp = of_find_property(np, "cpu0-supply", NULL);
  66                 if (pp)
  67                         return "cpu0";
  68         }
  69
  70         pp = of_find_property(np, "cpu-supply", NULL);
  71         if (pp)
  72                 return "cpu";
  73
  74         dev_dbg(dev, "no regulator for cpu%d\n", cpu);
  75         return NULL;
  76 }
  77
  78 static int allocate_resources(int cpu, struct device **cdev,
  79                               struct regulator **creg, struct clk **cclk)
  80 {
  81         struct device *cpu_dev;
  82         struct regulator *cpu_reg;
  83         struct clk *cpu_clk;
  84         int ret = 0;
  85         char *reg_cpu0 = "cpu0", *reg_cpu = "cpu", *reg;
  86
  87         cpu_dev = get_cpu_device(cpu);
  88         if (!cpu_dev) {
  89                 pr_err("failed to get cpu%d device\n", cpu);
  90                 return -ENODEV;
  91         }
  92
  93         /* Try "cpu0" for older DTs */
  94         if (!cpu)
  95                 reg = reg_cpu0;
  96         else
  97                 reg = reg_cpu;
  98
  99 try_again:
 100         cpu_reg = regulator_get_optional(cpu_dev, reg);
 101         ret = PTR_ERR_OR_ZERO(cpu_reg);
 102         if (ret) {
 103                 /*
 104                  * If cpu's regulator supply node is present, but regulator is
 105                  * not yet registered, we should try defering probe.
 106                  */
 107                 if (ret == -EPROBE_DEFER) {
 108                         dev_dbg(cpu_dev, "cpu%d regulator not ready, retry\n",
 109                                 cpu);
 110                         return ret;
 111                 }
 112
 113                 /* Try with "cpu-supply" */
 114                 if (reg == reg_cpu0) {
 115                         reg = reg_cpu;
 116                         goto try_again;
 117                 }
 118
 119                 dev_dbg(cpu_dev, "no regulator for cpu%d: %d\n", cpu, ret);
 120         }
 121
 122         cpu_clk = clk_get(cpu_dev, NULL);
 123         ret = PTR_ERR_OR_ZERO(cpu_clk);
 124         if (ret) {
 125                 /* put regulator */
 126                 if (!IS_ERR(cpu_reg))
 127                         regulator_put(cpu_reg);
 128
 129                 /*
 130                  * If cpu's clk node is present, but clock is not yet
 131                  * registered, we should try defering probe.
 132                  */
 133                 if (ret == -EPROBE_DEFER)
 134                         dev_dbg(cpu_dev, "cpu%d clock not ready, retry\n", cpu);
 135                 else
 136                         dev_err(cpu_dev, "failed to get cpu%d clock: %d\n", cpu,
 137                                 ret);
 138         } else {
 139                 *cdev = cpu_dev;
 140                 *creg = cpu_reg;
 141                 *cclk = cpu_clk;
 142         }
 143
 144         return ret;
 145 }
 146
 147 static int cpufreq_init(struct cpufreq_policy *policy)
 148 {
 149         struct cpufreq_frequency_table *freq_table;
 150         struct device_node *np;
 151         struct private_data *priv;
 152         struct device *cpu_dev;
 153         struct regulator *cpu_reg;
 154         struct clk *cpu_clk;
 155         struct dev_pm_opp *suspend_opp;
 156         unsigned int transition_latency;
 157         bool opp_v1 = false;
 158         const char *name;
 159         int ret;
 160
 161         ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
 162         if (ret) {
 163                 pr_err("%s: Failed to allocate resources: %d\n", __func__, ret);
 164                 return ret;
 165         }
 166
 167         np = of_node_get(cpu_dev->of_node);
 168         if (!np) {
 169                 dev_err(cpu_dev, "failed to find cpu%d node\n", policy->cpu);
 170                 ret = -ENOENT;
 171                 goto out_put_reg_clk;
 172         }
 173
 174         /* Get OPP-sharing information from "operating-points-v2" bindings */
 175         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus);
 176         if (ret) {
 177                 /*
 178                  * operating-points-v2 not supported, fallback to old method of
 179                  * finding shared-OPPs for backward compatibility.
 180                  */
 181                 if (ret == -ENOENT)
 182                         opp_v1 = true;
 183                 else
 184                         goto out_node_put;
 185         }
 186
 187         /*
 188          * OPP layer will be taking care of regulators now, but it needs to know
 189          * the name of the regulator first.
 190          */
 191         name = find_supply_name(cpu_dev, np);
 192         if (name) {
 193                 ret = dev_pm_opp_set_regulator(cpu_dev, name);
 194                 if (ret) {
 195                         dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n",
 196                                 policy->cpu, ret);
 197                         goto out_node_put;
 198                 }
 199         }
 200
 201         /*
 202          * Initialize OPP tables for all policy->cpus. They will be shared by
 203          * all CPUs which have marked their CPUs shared with OPP bindings.
 204          *
 205          * For platforms not using operating-points-v2 bindings, we do this
 206          * before updating policy->cpus. Otherwise, we will end up creating
 207          * duplicate OPPs for policy->cpus.
 208          *
 209          * OPPs might be populated at runtime, don't check for error here
 210          */
 211         dev_pm_opp_of_cpumask_add_table(policy->cpus);
 212
 213         /*
 214          * But we need OPP table to function so if it is not there let's
 215          * give platform code chance to provide it for us.
 216          */
 217         ret = dev_pm_opp_get_opp_count(cpu_dev);
 218         if (ret <= 0) {
 219                 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
 220                 ret = -EPROBE_DEFER;
 221                 goto out_free_opp;
 222         }
 223
 224         if (opp_v1) {
 225                 struct cpufreq_dt_platform_data *pd = cpufreq_get_driver_data();
 226
 227                 if (!pd || !pd->independent_clocks)
 228                         cpumask_setall(policy->cpus);
 229
 230                 /*
 231                  * OPP tables are initialized only for policy->cpu, do it for
 232                  * others as well.
 233                  */
 234                 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
 235                 if (ret)
 236                         dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 237                                 __func__, ret);
 238         }
 239
 240         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 241         if (!priv) {
 242                 ret = -ENOMEM;
 243                 goto out_free_opp;
 244         }
 245
 246         priv->reg_name = name;
 247         of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance);
 248
 249         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 250         if (ret) {
 251                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 252                 goto out_free_priv;
 253         }
 254
 255         priv->cpu_dev = cpu_dev;
 256         priv->cpu_reg = cpu_reg;
 257         policy->driver_data = priv;
 258
 259         policy->clk = cpu_clk;
 260
 261         rcu_read_lock();
 262         suspend_opp = dev_pm_opp_get_suspend_opp(cpu_dev);
 263         if (suspend_opp)
 264                 policy->suspend_freq = dev_pm_opp_get_freq(suspend_opp) / 1000;
 265         rcu_read_unlock();
 266
 267         ret = cpufreq_table_validate_and_show(policy, freq_table);
 268         if (ret) {
 269                 dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
 270                         ret);
 271                 goto out_free_cpufreq_table;
 272         }
 273
 274         /* Support turbo/boost mode */
 275         if (policy_has_boost_freq(policy)) {
 276                 /* This gets disabled by core on driver unregister */
 277                 ret = cpufreq_enable_boost_support();
 278                 if (ret)
 279                         goto out_free_cpufreq_table;
 280                 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
 281         }
 282
 283         transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
 284         if (!transition_latency)
 285                 transition_latency = CPUFREQ_ETERNAL;
 286
 287         policy->cpuinfo.transition_latency = transition_latency;
 288
 289         of_node_put(np);
 290
 291         return 0;
 292
 293 out_free_cpufreq_table:
 294         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 295 out_free_priv:
 296         kfree(priv);
 297 out_free_opp:
 298         dev_pm_opp_of_cpumask_remove_table(policy->cpus);
 299         if (name)
 300                 dev_pm_opp_put_regulator(cpu_dev);
 301 out_node_put:
 302         of_node_put(np);
 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");