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 dev_pm_opp *opp;
  49         struct cpufreq_frequency_table *freq_table = policy->freq_table;
  50         struct clk *cpu_clk = policy->clk;
  51         struct private_data *priv = policy->driver_data;
  52         struct device *cpu_dev = priv->cpu_dev;
  53         struct regulator *cpu_reg = priv->cpu_reg;
  54         unsigned long volt = 0, tol = 0;
  55         int volt_old = 0;
  56         unsigned int old_freq, new_freq;
  57         long freq_Hz, freq_exact;
  58         int ret;
  59
  60         freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
  61         if (freq_Hz <= 0)
  62                 freq_Hz = freq_table[index].frequency * 1000;
  63
  64         freq_exact = freq_Hz;
  65         new_freq = freq_Hz / 1000;
  66         old_freq = clk_get_rate(cpu_clk) / 1000;
  67
  68         if (!IS_ERR(cpu_reg)) {
  69                 unsigned long opp_freq;
  70
  71                 rcu_read_lock();
  72                 opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz);
  73                 if (IS_ERR(opp)) {
  74                         rcu_read_unlock();
  75                         dev_err(cpu_dev, "failed to find OPP for %ld\n",
  76                                 freq_Hz);
  77                         return PTR_ERR(opp);
  78                 }
  79                 volt = dev_pm_opp_get_voltage(opp);
  80                 opp_freq = dev_pm_opp_get_freq(opp);
  81                 rcu_read_unlock();
  82                 tol = volt * priv->voltage_tolerance / 100;
  83                 volt_old = regulator_get_voltage(cpu_reg);
  84                 dev_dbg(cpu_dev, "Found OPP: %ld kHz, %ld uV\n",
  85                         opp_freq / 1000, volt);
  86         }
  87
  88         dev_dbg(cpu_dev, "%u MHz, %d mV --> %u MHz, %ld mV\n",
  89                 old_freq / 1000, (volt_old > 0) ? volt_old / 1000 : -1,
  90                 new_freq / 1000, volt ? volt / 1000 : -1);
  91
  92         /* scaling up?  scale voltage before frequency */
  93         if (!IS_ERR(cpu_reg) && new_freq > old_freq) {
  94                 ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
  95                 if (ret) {
  96                         dev_err(cpu_dev, "failed to scale voltage up: %d\n",
  97                                 ret);
  98                         return ret;
  99                 }
 100         }
 101
 102         ret = clk_set_rate(cpu_clk, freq_exact);
 103         if (ret) {
 104                 dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
 105                 if (!IS_ERR(cpu_reg) && volt_old > 0)
 106                         regulator_set_voltage_tol(cpu_reg, volt_old, tol);
 107                 return ret;
 108         }
 109
 110         /* scaling down?  scale voltage after frequency */
 111         if (!IS_ERR(cpu_reg) && new_freq < old_freq) {
 112                 ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
 113                 if (ret) {
 114                         dev_err(cpu_dev, "failed to scale voltage down: %d\n",
 115                                 ret);
 116                         clk_set_rate(cpu_clk, old_freq * 1000);
 117                 }
 118         }
 119
 120         return ret;
 121 }
 122
 123 /*
 124  * An earlier version of opp-v1 bindings used to name the regulator
 125  * "cpu0-supply", we still need to handle that for backwards compatibility.
 126  */
 127 static const char *find_supply_name(struct device *dev, struct device_node *np)
 128 {
 129         struct property *pp;
 130         int cpu = dev->id;
 131
 132         /* Try "cpu0" for older DTs */
 133         if (!cpu) {
 134                 pp = of_find_property(np, "cpu0-supply", NULL);
 135                 if (pp)
 136                         return "cpu0";
 137         }
 138
 139         pp = of_find_property(np, "cpu-supply", NULL);
 140         if (pp)
 141                 return "cpu";
 142
 143         dev_dbg(dev, "no regulator for cpu%d\n", cpu);
 144         return NULL;
 145 }
 146
 147 static int allocate_resources(int cpu, struct device **cdev,
 148                               struct regulator **creg, struct clk **cclk)
 149 {
 150         struct device *cpu_dev;
 151         struct regulator *cpu_reg;
 152         struct clk *cpu_clk;
 153         int ret = 0;
 154         char *reg_cpu0 = "cpu0", *reg_cpu = "cpu", *reg;
 155
 156         cpu_dev = get_cpu_device(cpu);
 157         if (!cpu_dev) {
 158                 pr_err("failed to get cpu%d device\n", cpu);
 159                 return -ENODEV;
 160         }
 161
 162         /* Try "cpu0" for older DTs */
 163         if (!cpu)
 164                 reg = reg_cpu0;
 165         else
 166                 reg = reg_cpu;
 167
 168 try_again:
 169         cpu_reg = regulator_get_optional(cpu_dev, reg);
 170         ret = PTR_ERR_OR_ZERO(cpu_reg);
 171         if (ret) {
 172                 /*
 173                  * If cpu's regulator supply node is present, but regulator is
 174                  * not yet registered, we should try defering probe.
 175                  */
 176                 if (ret == -EPROBE_DEFER) {
 177                         dev_dbg(cpu_dev, "cpu%d regulator not ready, retry\n",
 178                                 cpu);
 179                         return ret;
 180                 }
 181
 182                 /* Try with "cpu-supply" */
 183                 if (reg == reg_cpu0) {
 184                         reg = reg_cpu;
 185                         goto try_again;
 186                 }
 187
 188                 dev_dbg(cpu_dev, "no regulator for cpu%d: %d\n", cpu, ret);
 189         }
 190
 191         cpu_clk = clk_get(cpu_dev, NULL);
 192         ret = PTR_ERR_OR_ZERO(cpu_clk);
 193         if (ret) {
 194                 /* put regulator */
 195                 if (!IS_ERR(cpu_reg))
 196                         regulator_put(cpu_reg);
 197
 198                 /*
 199                  * If cpu's clk node is present, but clock is not yet
 200                  * registered, we should try defering probe.
 201                  */
 202                 if (ret == -EPROBE_DEFER)
 203                         dev_dbg(cpu_dev, "cpu%d clock not ready, retry\n", cpu);
 204                 else
 205                         dev_err(cpu_dev, "failed to get cpu%d clock: %d\n", cpu,
 206                                 ret);
 207         } else {
 208                 *cdev = cpu_dev;
 209                 *creg = cpu_reg;
 210                 *cclk = cpu_clk;
 211         }
 212
 213         return ret;
 214 }
 215
 216 static int cpufreq_init(struct cpufreq_policy *policy)
 217 {
 218         struct cpufreq_frequency_table *freq_table;
 219         struct device_node *np;
 220         struct private_data *priv;
 221         struct device *cpu_dev;
 222         struct regulator *cpu_reg;
 223         struct clk *cpu_clk;
 224         struct dev_pm_opp *suspend_opp;
 225         unsigned int transition_latency;
 226         bool opp_v1 = false;
 227         const char *name;
 228         int ret;
 229
 230         ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
 231         if (ret) {
 232                 pr_err("%s: Failed to allocate resources: %d\n", __func__, ret);
 233                 return ret;
 234         }
 235
 236         np = of_node_get(cpu_dev->of_node);
 237         if (!np) {
 238                 dev_err(cpu_dev, "failed to find cpu%d node\n", policy->cpu);
 239                 ret = -ENOENT;
 240                 goto out_put_reg_clk;
 241         }
 242
 243         /* Get OPP-sharing information from "operating-points-v2" bindings */
 244         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus);
 245         if (ret) {
 246                 /*
 247                  * operating-points-v2 not supported, fallback to old method of
 248                  * finding shared-OPPs for backward compatibility.
 249                  */
 250                 if (ret == -ENOENT)
 251                         opp_v1 = true;
 252                 else
 253                         goto out_node_put;
 254         }
 255
 256         /*
 257          * OPP layer will be taking care of regulators now, but it needs to know
 258          * the name of the regulator first.
 259          */
 260         name = find_supply_name(cpu_dev, np);
 261         if (name) {
 262                 ret = dev_pm_opp_set_regulator(cpu_dev, name);
 263                 if (ret) {
 264                         dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n",
 265                                 policy->cpu, ret);
 266                         goto out_node_put;
 267                 }
 268         }
 269
 270         /*
 271          * Initialize OPP tables for all policy->cpus. They will be shared by
 272          * all CPUs which have marked their CPUs shared with OPP bindings.
 273          *
 274          * For platforms not using operating-points-v2 bindings, we do this
 275          * before updating policy->cpus. Otherwise, we will end up creating
 276          * duplicate OPPs for policy->cpus.
 277          *
 278          * OPPs might be populated at runtime, don't check for error here
 279          */
 280         dev_pm_opp_of_cpumask_add_table(policy->cpus);
 281
 282         /*
 283          * But we need OPP table to function so if it is not there let's
 284          * give platform code chance to provide it for us.
 285          */
 286         ret = dev_pm_opp_get_opp_count(cpu_dev);
 287         if (ret <= 0) {
 288                 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
 289                 ret = -EPROBE_DEFER;
 290                 goto out_free_opp;
 291         }
 292
 293         if (opp_v1) {
 294                 struct cpufreq_dt_platform_data *pd = cpufreq_get_driver_data();
 295
 296                 if (!pd || !pd->independent_clocks)
 297                         cpumask_setall(policy->cpus);
 298
 299                 /*
 300                  * OPP tables are initialized only for policy->cpu, do it for
 301                  * others as well.
 302                  */
 303                 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
 304                 if (ret)
 305                         dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 306                                 __func__, ret);
 307         }
 308
 309         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 310         if (!priv) {
 311                 ret = -ENOMEM;
 312                 goto out_free_opp;
 313         }
 314
 315         priv->reg_name = name;
 316         of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance);
 317
 318         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 319         if (ret) {
 320                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 321                 goto out_free_priv;
 322         }
 323
 324         priv->cpu_dev = cpu_dev;
 325         priv->cpu_reg = cpu_reg;
 326         policy->driver_data = priv;
 327
 328         policy->clk = cpu_clk;
 329
 330         rcu_read_lock();
 331         suspend_opp = dev_pm_opp_get_suspend_opp(cpu_dev);
 332         if (suspend_opp)
 333                 policy->suspend_freq = dev_pm_opp_get_freq(suspend_opp) / 1000;
 334         rcu_read_unlock();
 335
 336         ret = cpufreq_table_validate_and_show(policy, freq_table);
 337         if (ret) {
 338                 dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
 339                         ret);
 340                 goto out_free_cpufreq_table;
 341         }
 342
 343         /* Support turbo/boost mode */
 344         if (policy_has_boost_freq(policy)) {
 345                 /* This gets disabled by core on driver unregister */
 346                 ret = cpufreq_enable_boost_support();
 347                 if (ret)
 348                         goto out_free_cpufreq_table;
 349                 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
 350         }
 351
 352         transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
 353         if (!transition_latency)
 354                 transition_latency = CPUFREQ_ETERNAL;
 355
 356         policy->cpuinfo.transition_latency = transition_latency;
 357
 358         of_node_put(np);
 359
 360         return 0;
 361
 362 out_free_cpufreq_table:
 363         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 364 out_free_priv:
 365         kfree(priv);
 366 out_free_opp:
 367         dev_pm_opp_of_cpumask_remove_table(policy->cpus);
 368         if (name)
 369                 dev_pm_opp_put_regulator(cpu_dev);
 370 out_node_put:
 371         of_node_put(np);
 372 out_put_reg_clk:
 373         clk_put(cpu_clk);
 374         if (!IS_ERR(cpu_reg))
 375                 regulator_put(cpu_reg);
 376
 377         return ret;
 378 }
 379
 380 static int cpufreq_exit(struct cpufreq_policy *policy)
 381 {
 382         struct private_data *priv = policy->driver_data;
 383
 384         cpufreq_cooling_unregister(priv->cdev);
 385         dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
 386         dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
 387         if (priv->reg_name)
 388                 dev_pm_opp_put_regulator(priv->cpu_dev);
 389
 390         clk_put(policy->clk);
 391         if (!IS_ERR(priv->cpu_reg))
 392                 regulator_put(priv->cpu_reg);
 393         kfree(priv);
 394
 395         return 0;
 396 }
 397
 398 static void cpufreq_ready(struct cpufreq_policy *policy)
 399 {
 400         struct private_data *priv = policy->driver_data;
 401         struct device_node *np = of_node_get(priv->cpu_dev->of_node);
 402
 403         if (WARN_ON(!np))
 404                 return;
 405
 406         /*
 407          * For now, just loading the cooling device;
 408          * thermal DT code takes care of matching them.
 409          */
 410         if (of_find_property(np, "#cooling-cells", NULL)) {
 411                 u32 power_coefficient = 0;
 412
 413                 of_property_read_u32(np, "dynamic-power-coefficient",
 414                                      &power_coefficient);
 415
 416                 priv->cdev = of_cpufreq_power_cooling_register(np,
 417                                 policy->related_cpus, power_coefficient, NULL);
 418                 if (IS_ERR(priv->cdev)) {
 419                         dev_err(priv->cpu_dev,
 420                                 "running cpufreq without cooling device: %ld\n",
 421                                 PTR_ERR(priv->cdev));
 422
 423                         priv->cdev = NULL;
 424                 }
 425         }
 426
 427         of_node_put(np);
 428 }
 429
 430 static struct cpufreq_driver dt_cpufreq_driver = {
 431         .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 432         .verify = cpufreq_generic_frequency_table_verify,
 433         .target_index = set_target,
 434         .get = cpufreq_generic_get,
 435         .init = cpufreq_init,
 436         .exit = cpufreq_exit,
 437         .ready = cpufreq_ready,
 438         .name = "cpufreq-dt",
 439         .attr = cpufreq_dt_attr,
 440         .suspend = cpufreq_generic_suspend,
 441 };
 442
 443 static int dt_cpufreq_probe(struct platform_device *pdev)
 444 {
 445         struct device *cpu_dev;
 446         struct regulator *cpu_reg;
 447         struct clk *cpu_clk;
 448         int ret;
 449
 450         /*
 451          * All per-cluster (CPUs sharing clock/voltages) initialization is done
 452          * from ->init(). In probe(), we just need to make sure that clk and
 453          * regulators are available. Else defer probe and retry.
 454          *
 455          * FIXME: Is checking this only for CPU0 sufficient ?
 456          */
 457         ret = allocate_resources(0, &cpu_dev, &cpu_reg, &cpu_clk);
 458         if (ret)
 459                 return ret;
 460
 461         clk_put(cpu_clk);
 462         if (!IS_ERR(cpu_reg))
 463                 regulator_put(cpu_reg);
 464
 465         dt_cpufreq_driver.driver_data = dev_get_platdata(&pdev->dev);
 466
 467         ret = cpufreq_register_driver(&dt_cpufreq_driver);
 468         if (ret)
 469                 dev_err(cpu_dev, "failed register driver: %d\n", ret);
 470
 471         return ret;
 472 }
 473
 474 static int dt_cpufreq_remove(struct platform_device *pdev)
 475 {
 476         cpufreq_unregister_driver(&dt_cpufreq_driver);
 477         return 0;
 478 }
 479
 480 static struct platform_driver dt_cpufreq_platdrv = {
 481         .driver = {
 482                 .name   = "cpufreq-dt",
 483         },
 484         .probe          = dt_cpufreq_probe,
 485         .remove         = dt_cpufreq_remove,
 486 };
 487 module_platform_driver(dt_cpufreq_platdrv);
 488
 489 MODULE_ALIAS("platform:cpufreq-dt");
 490 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 491 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 492 MODULE_DESCRIPTION("Generic cpufreq driver");
 493 MODULE_LICENSE("GPL");