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 long min_uV = ~0, max_uV = 0;
 226         unsigned int transition_latency;
 227         bool opp_v1 = false;
 228         const char *name;
 229         int ret;
 230
 231         ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
 232         if (ret) {
 233                 pr_err("%s: Failed to allocate resources: %d\n", __func__, ret);
 234                 return ret;
 235         }
 236
 237         np = of_node_get(cpu_dev->of_node);
 238         if (!np) {
 239                 dev_err(cpu_dev, "failed to find cpu%d node\n", policy->cpu);
 240                 ret = -ENOENT;
 241                 goto out_put_reg_clk;
 242         }
 243
 244         /* Get OPP-sharing information from "operating-points-v2" bindings */
 245         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus);
 246         if (ret) {
 247                 /*
 248                  * operating-points-v2 not supported, fallback to old method of
 249                  * finding shared-OPPs for backward compatibility.
 250                  */
 251                 if (ret == -ENOENT)
 252                         opp_v1 = true;
 253                 else
 254                         goto out_node_put;
 255         }
 256
 257         /*
 258          * OPP layer will be taking care of regulators now, but it needs to know
 259          * the name of the regulator first.
 260          */
 261         name = find_supply_name(cpu_dev, np);
 262         if (name) {
 263                 ret = dev_pm_opp_set_regulator(cpu_dev, name);
 264                 if (ret) {
 265                         dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n",
 266                                 policy->cpu, ret);
 267                         goto out_node_put;
 268                 }
 269         }
 270
 271         /*
 272          * Initialize OPP tables for all policy->cpus. They will be shared by
 273          * all CPUs which have marked their CPUs shared with OPP bindings.
 274          *
 275          * For platforms not using operating-points-v2 bindings, we do this
 276          * before updating policy->cpus. Otherwise, we will end up creating
 277          * duplicate OPPs for policy->cpus.
 278          *
 279          * OPPs might be populated at runtime, don't check for error here
 280          */
 281         dev_pm_opp_of_cpumask_add_table(policy->cpus);
 282
 283         /*
 284          * But we need OPP table to function so if it is not there let's
 285          * give platform code chance to provide it for us.
 286          */
 287         ret = dev_pm_opp_get_opp_count(cpu_dev);
 288         if (ret <= 0) {
 289                 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
 290                 ret = -EPROBE_DEFER;
 291                 goto out_free_opp;
 292         }
 293
 294         if (opp_v1) {
 295                 struct cpufreq_dt_platform_data *pd = cpufreq_get_driver_data();
 296
 297                 if (!pd || !pd->independent_clocks)
 298                         cpumask_setall(policy->cpus);
 299
 300                 /*
 301                  * OPP tables are initialized only for policy->cpu, do it for
 302                  * others as well.
 303                  */
 304                 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
 305                 if (ret)
 306                         dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 307                                 __func__, ret);
 308         }
 309
 310         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 311         if (!priv) {
 312                 ret = -ENOMEM;
 313                 goto out_free_opp;
 314         }
 315
 316         priv->reg_name = name;
 317         of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance);
 318
 319         transition_latency = dev_pm_opp_get_max_clock_latency(cpu_dev);
 320         if (!transition_latency)
 321                 transition_latency = CPUFREQ_ETERNAL;
 322
 323         if (!IS_ERR(cpu_reg)) {
 324                 unsigned long opp_freq = 0;
 325
 326                 /*
 327                  * Disable any OPPs where the connected regulator isn't able to
 328                  * provide the specified voltage and record minimum and maximum
 329                  * voltage levels.
 330                  */
 331                 while (1) {
 332                         struct dev_pm_opp *opp;
 333                         unsigned long opp_uV, tol_uV;
 334
 335                         rcu_read_lock();
 336                         opp = dev_pm_opp_find_freq_ceil(cpu_dev, &opp_freq);
 337                         if (IS_ERR(opp)) {
 338                                 rcu_read_unlock();
 339                                 break;
 340                         }
 341                         opp_uV = dev_pm_opp_get_voltage(opp);
 342                         rcu_read_unlock();
 343
 344                         tol_uV = opp_uV * priv->voltage_tolerance / 100;
 345                         if (regulator_is_supported_voltage(cpu_reg,
 346                                                            opp_uV - tol_uV,
 347                                                            opp_uV + tol_uV)) {
 348                                 if (opp_uV < min_uV)
 349                                         min_uV = opp_uV;
 350                                 if (opp_uV > max_uV)
 351                                         max_uV = opp_uV;
 352                         }
 353
 354                         opp_freq++;
 355                 }
 356
 357                 ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV);
 358                 if (ret > 0)
 359                         transition_latency += ret * 1000;
 360         }
 361
 362         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 363         if (ret) {
 364                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 365                 goto out_free_priv;
 366         }
 367
 368         priv->cpu_dev = cpu_dev;
 369         priv->cpu_reg = cpu_reg;
 370         policy->driver_data = priv;
 371
 372         policy->clk = cpu_clk;
 373
 374         rcu_read_lock();
 375         suspend_opp = dev_pm_opp_get_suspend_opp(cpu_dev);
 376         if (suspend_opp)
 377                 policy->suspend_freq = dev_pm_opp_get_freq(suspend_opp) / 1000;
 378         rcu_read_unlock();
 379
 380         ret = cpufreq_table_validate_and_show(policy, freq_table);
 381         if (ret) {
 382                 dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
 383                         ret);
 384                 goto out_free_cpufreq_table;
 385         }
 386
 387         /* Support turbo/boost mode */
 388         if (policy_has_boost_freq(policy)) {
 389                 /* This gets disabled by core on driver unregister */
 390                 ret = cpufreq_enable_boost_support();
 391                 if (ret)
 392                         goto out_free_cpufreq_table;
 393                 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
 394         }
 395
 396         policy->cpuinfo.transition_latency = transition_latency;
 397
 398         of_node_put(np);
 399
 400         return 0;
 401
 402 out_free_cpufreq_table:
 403         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 404 out_free_priv:
 405         kfree(priv);
 406 out_free_opp:
 407         dev_pm_opp_of_cpumask_remove_table(policy->cpus);
 408         if (name)
 409                 dev_pm_opp_put_regulator(cpu_dev);
 410 out_node_put:
 411         of_node_put(np);
 412 out_put_reg_clk:
 413         clk_put(cpu_clk);
 414         if (!IS_ERR(cpu_reg))
 415                 regulator_put(cpu_reg);
 416
 417         return ret;
 418 }
 419
 420 static int cpufreq_exit(struct cpufreq_policy *policy)
 421 {
 422         struct private_data *priv = policy->driver_data;
 423
 424         cpufreq_cooling_unregister(priv->cdev);
 425         dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
 426         dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
 427         if (priv->reg_name)
 428                 dev_pm_opp_put_regulator(priv->cpu_dev);
 429
 430         clk_put(policy->clk);
 431         if (!IS_ERR(priv->cpu_reg))
 432                 regulator_put(priv->cpu_reg);
 433         kfree(priv);
 434
 435         return 0;
 436 }
 437
 438 static void cpufreq_ready(struct cpufreq_policy *policy)
 439 {
 440         struct private_data *priv = policy->driver_data;
 441         struct device_node *np = of_node_get(priv->cpu_dev->of_node);
 442
 443         if (WARN_ON(!np))
 444                 return;
 445
 446         /*
 447          * For now, just loading the cooling device;
 448          * thermal DT code takes care of matching them.
 449          */
 450         if (of_find_property(np, "#cooling-cells", NULL)) {
 451                 u32 power_coefficient = 0;
 452
 453                 of_property_read_u32(np, "dynamic-power-coefficient",
 454                                      &power_coefficient);
 455
 456                 priv->cdev = of_cpufreq_power_cooling_register(np,
 457                                 policy->related_cpus, power_coefficient, NULL);
 458                 if (IS_ERR(priv->cdev)) {
 459                         dev_err(priv->cpu_dev,
 460                                 "running cpufreq without cooling device: %ld\n",
 461                                 PTR_ERR(priv->cdev));
 462
 463                         priv->cdev = NULL;
 464                 }
 465         }
 466
 467         of_node_put(np);
 468 }
 469
 470 static struct cpufreq_driver dt_cpufreq_driver = {
 471         .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 472         .verify = cpufreq_generic_frequency_table_verify,
 473         .target_index = set_target,
 474         .get = cpufreq_generic_get,
 475         .init = cpufreq_init,
 476         .exit = cpufreq_exit,
 477         .ready = cpufreq_ready,
 478         .name = "cpufreq-dt",
 479         .attr = cpufreq_dt_attr,
 480         .suspend = cpufreq_generic_suspend,
 481 };
 482
 483 static int dt_cpufreq_probe(struct platform_device *pdev)
 484 {
 485         struct device *cpu_dev;
 486         struct regulator *cpu_reg;
 487         struct clk *cpu_clk;
 488         int ret;
 489
 490         /*
 491          * All per-cluster (CPUs sharing clock/voltages) initialization is done
 492          * from ->init(). In probe(), we just need to make sure that clk and
 493          * regulators are available. Else defer probe and retry.
 494          *
 495          * FIXME: Is checking this only for CPU0 sufficient ?
 496          */
 497         ret = allocate_resources(0, &cpu_dev, &cpu_reg, &cpu_clk);
 498         if (ret)
 499                 return ret;
 500
 501         clk_put(cpu_clk);
 502         if (!IS_ERR(cpu_reg))
 503                 regulator_put(cpu_reg);
 504
 505         dt_cpufreq_driver.driver_data = dev_get_platdata(&pdev->dev);
 506
 507         ret = cpufreq_register_driver(&dt_cpufreq_driver);
 508         if (ret)
 509                 dev_err(cpu_dev, "failed register driver: %d\n", ret);
 510
 511         return ret;
 512 }
 513
 514 static int dt_cpufreq_remove(struct platform_device *pdev)
 515 {
 516         cpufreq_unregister_driver(&dt_cpufreq_driver);
 517         return 0;
 518 }
 519
 520 static struct platform_driver dt_cpufreq_platdrv = {
 521         .driver = {
 522                 .name   = "cpufreq-dt",
 523         },
 524         .probe          = dt_cpufreq_probe,
 525         .remove         = dt_cpufreq_remove,
 526 };
 527 module_platform_driver(dt_cpufreq_platdrv);
 528
 529 MODULE_ALIAS("platform:cpufreq-dt");
 530 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 531 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 532 MODULE_DESCRIPTION("Generic cpufreq driver");
 533 MODULE_LICENSE("GPL");