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 };
  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 dev_pm_opp *opp;
  48         struct cpufreq_frequency_table *freq_table = policy->freq_table;
  49         struct clk *cpu_clk = policy->clk;
  50         struct private_data *priv = policy->driver_data;
  51         struct device *cpu_dev = priv->cpu_dev;
  52         struct regulator *cpu_reg = priv->cpu_reg;
  53         unsigned long volt = 0, tol = 0;
  54         int volt_old = 0;
  55         unsigned int old_freq, new_freq;
  56         long freq_Hz, freq_exact;
  57         int ret;
  58
  59         freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
  60         if (freq_Hz <= 0)
  61                 freq_Hz = freq_table[index].frequency * 1000;
  62
  63         freq_exact = freq_Hz;
  64         new_freq = freq_Hz / 1000;
  65         old_freq = clk_get_rate(cpu_clk) / 1000;
  66
  67         if (!IS_ERR(cpu_reg)) {
  68                 unsigned long opp_freq;
  69
  70                 rcu_read_lock();
  71                 opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz);
  72                 if (IS_ERR(opp)) {
  73                         rcu_read_unlock();
  74                         dev_err(cpu_dev, "failed to find OPP for %ld\n",
  75                                 freq_Hz);
  76                         return PTR_ERR(opp);
  77                 }
  78                 volt = dev_pm_opp_get_voltage(opp);
  79                 opp_freq = dev_pm_opp_get_freq(opp);
  80                 rcu_read_unlock();
  81                 tol = volt * priv->voltage_tolerance / 100;
  82                 volt_old = regulator_get_voltage(cpu_reg);
  83                 dev_dbg(cpu_dev, "Found OPP: %ld kHz, %ld uV\n",
  84                         opp_freq / 1000, volt);
  85         }
  86
  87         dev_dbg(cpu_dev, "%u MHz, %d mV --> %u MHz, %ld mV\n",
  88                 old_freq / 1000, (volt_old > 0) ? volt_old / 1000 : -1,
  89                 new_freq / 1000, volt ? volt / 1000 : -1);
  90
  91         /* scaling up?  scale voltage before frequency */
  92         if (!IS_ERR(cpu_reg) && new_freq > old_freq) {
  93                 ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
  94                 if (ret) {
  95                         dev_err(cpu_dev, "failed to scale voltage up: %d\n",
  96                                 ret);
  97                         return ret;
  98                 }
  99         }
 100
 101         ret = clk_set_rate(cpu_clk, freq_exact);
 102         if (ret) {
 103                 dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
 104                 if (!IS_ERR(cpu_reg) && volt_old > 0)
 105                         regulator_set_voltage_tol(cpu_reg, volt_old, tol);
 106                 return ret;
 107         }
 108
 109         /* scaling down?  scale voltage after frequency */
 110         if (!IS_ERR(cpu_reg) && new_freq < old_freq) {
 111                 ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
 112                 if (ret) {
 113                         dev_err(cpu_dev, "failed to scale voltage down: %d\n",
 114                                 ret);
 115                         clk_set_rate(cpu_clk, old_freq * 1000);
 116                 }
 117         }
 118
 119         return ret;
 120 }
 121
 122 static int allocate_resources(int cpu, struct device **cdev,
 123                               struct regulator **creg, struct clk **cclk)
 124 {
 125         struct device *cpu_dev;
 126         struct regulator *cpu_reg;
 127         struct clk *cpu_clk;
 128         int ret = 0;
 129         char *reg_cpu0 = "cpu0", *reg_cpu = "cpu", *reg;
 130
 131         cpu_dev = get_cpu_device(cpu);
 132         if (!cpu_dev) {
 133                 pr_err("failed to get cpu%d device\n", cpu);
 134                 return -ENODEV;
 135         }
 136
 137         /* Try "cpu0" for older DTs */
 138         if (!cpu)
 139                 reg = reg_cpu0;
 140         else
 141                 reg = reg_cpu;
 142
 143 try_again:
 144         cpu_reg = regulator_get_optional(cpu_dev, reg);
 145         if (IS_ERR(cpu_reg)) {
 146                 /*
 147                  * If cpu's regulator supply node is present, but regulator is
 148                  * not yet registered, we should try defering probe.
 149                  */
 150                 if (PTR_ERR(cpu_reg) == -EPROBE_DEFER) {
 151                         dev_dbg(cpu_dev, "cpu%d regulator not ready, retry\n",
 152                                 cpu);
 153                         return -EPROBE_DEFER;
 154                 }
 155
 156                 /* Try with "cpu-supply" */
 157                 if (reg == reg_cpu0) {
 158                         reg = reg_cpu;
 159                         goto try_again;
 160                 }
 161
 162                 dev_dbg(cpu_dev, "no regulator for cpu%d: %ld\n",
 163                         cpu, PTR_ERR(cpu_reg));
 164         }
 165
 166         cpu_clk = clk_get(cpu_dev, NULL);
 167         if (IS_ERR(cpu_clk)) {
 168                 /* put regulator */
 169                 if (!IS_ERR(cpu_reg))
 170                         regulator_put(cpu_reg);
 171
 172                 ret = PTR_ERR(cpu_clk);
 173
 174                 /*
 175                  * If cpu's clk node is present, but clock is not yet
 176                  * registered, we should try defering probe.
 177                  */
 178                 if (ret == -EPROBE_DEFER)
 179                         dev_dbg(cpu_dev, "cpu%d clock not ready, retry\n", cpu);
 180                 else
 181                         dev_err(cpu_dev, "failed to get cpu%d clock: %d\n", cpu,
 182                                 ret);
 183         } else {
 184                 *cdev = cpu_dev;
 185                 *creg = cpu_reg;
 186                 *cclk = cpu_clk;
 187         }
 188
 189         return ret;
 190 }
 191
 192 static int cpufreq_init(struct cpufreq_policy *policy)
 193 {
 194         struct cpufreq_frequency_table *freq_table;
 195         struct device_node *np;
 196         struct private_data *priv;
 197         struct device *cpu_dev;
 198         struct regulator *cpu_reg;
 199         struct clk *cpu_clk;
 200         struct dev_pm_opp *suspend_opp;
 201         unsigned long min_uV = ~0, max_uV = 0;
 202         unsigned int transition_latency;
 203         bool need_update = false;
 204         int ret;
 205
 206         ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
 207         if (ret) {
 208                 pr_err("%s: Failed to allocate resources: %d\n", __func__, ret);
 209                 return ret;
 210         }
 211
 212         np = of_node_get(cpu_dev->of_node);
 213         if (!np) {
 214                 dev_err(cpu_dev, "failed to find cpu%d node\n", policy->cpu);
 215                 ret = -ENOENT;
 216                 goto out_put_reg_clk;
 217         }
 218
 219         /* Get OPP-sharing information from "operating-points-v2" bindings */
 220         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus);
 221         if (ret) {
 222                 /*
 223                  * operating-points-v2 not supported, fallback to old method of
 224                  * finding shared-OPPs for backward compatibility.
 225                  */
 226                 if (ret == -ENOENT)
 227                         need_update = true;
 228                 else
 229                         goto out_node_put;
 230         }
 231
 232         /*
 233          * Initialize OPP tables for all policy->cpus. They will be shared by
 234          * all CPUs which have marked their CPUs shared with OPP bindings.
 235          *
 236          * For platforms not using operating-points-v2 bindings, we do this
 237          * before updating policy->cpus. Otherwise, we will end up creating
 238          * duplicate OPPs for policy->cpus.
 239          *
 240          * OPPs might be populated at runtime, don't check for error here
 241          */
 242         dev_pm_opp_of_cpumask_add_table(policy->cpus);
 243
 244         /*
 245          * But we need OPP table to function so if it is not there let's
 246          * give platform code chance to provide it for us.
 247          */
 248         ret = dev_pm_opp_get_opp_count(cpu_dev);
 249         if (ret <= 0) {
 250                 pr_debug("OPP table is not ready, deferring probe\n");
 251                 ret = -EPROBE_DEFER;
 252                 goto out_free_opp;
 253         }
 254
 255         if (need_update) {
 256                 struct cpufreq_dt_platform_data *pd = cpufreq_get_driver_data();
 257
 258                 if (!pd || !pd->independent_clocks)
 259                         cpumask_setall(policy->cpus);
 260
 261                 /*
 262                  * OPP tables are initialized only for policy->cpu, do it for
 263                  * others as well.
 264                  */
 265                 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
 266                 if (ret)
 267                         dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 268                                 __func__, ret);
 269
 270                 of_property_read_u32(np, "clock-latency", &transition_latency);
 271         } else {
 272                 transition_latency = dev_pm_opp_get_max_clock_latency(cpu_dev);
 273         }
 274
 275         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 276         if (!priv) {
 277                 ret = -ENOMEM;
 278                 goto out_free_opp;
 279         }
 280
 281         of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance);
 282
 283         if (!transition_latency)
 284                 transition_latency = CPUFREQ_ETERNAL;
 285
 286         if (!IS_ERR(cpu_reg)) {
 287                 unsigned long opp_freq = 0;
 288
 289                 /*
 290                  * Disable any OPPs where the connected regulator isn't able to
 291                  * provide the specified voltage and record minimum and maximum
 292                  * voltage levels.
 293                  */
 294                 while (1) {
 295                         struct dev_pm_opp *opp;
 296                         unsigned long opp_uV, tol_uV;
 297
 298                         rcu_read_lock();
 299                         opp = dev_pm_opp_find_freq_ceil(cpu_dev, &opp_freq);
 300                         if (IS_ERR(opp)) {
 301                                 rcu_read_unlock();
 302                                 break;
 303                         }
 304                         opp_uV = dev_pm_opp_get_voltage(opp);
 305                         rcu_read_unlock();
 306
 307                         tol_uV = opp_uV * priv->voltage_tolerance / 100;
 308                         if (regulator_is_supported_voltage(cpu_reg,
 309                                                            opp_uV - tol_uV,
 310                                                            opp_uV + tol_uV)) {
 311                                 if (opp_uV < min_uV)
 312                                         min_uV = opp_uV;
 313                                 if (opp_uV > max_uV)
 314                                         max_uV = opp_uV;
 315                         } else {
 316                                 dev_pm_opp_disable(cpu_dev, opp_freq);
 317                         }
 318
 319                         opp_freq++;
 320                 }
 321
 322                 ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV);
 323                 if (ret > 0)
 324                         transition_latency += ret * 1000;
 325         }
 326
 327         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 328         if (ret) {
 329                 pr_err("failed to init cpufreq table: %d\n", ret);
 330                 goto out_free_priv;
 331         }
 332
 333         priv->cpu_dev = cpu_dev;
 334         priv->cpu_reg = cpu_reg;
 335         policy->driver_data = priv;
 336
 337         policy->clk = cpu_clk;
 338
 339         rcu_read_lock();
 340         suspend_opp = dev_pm_opp_get_suspend_opp(cpu_dev);
 341         if (suspend_opp)
 342                 policy->suspend_freq = dev_pm_opp_get_freq(suspend_opp) / 1000;
 343         rcu_read_unlock();
 344
 345         ret = cpufreq_table_validate_and_show(policy, freq_table);
 346         if (ret) {
 347                 dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
 348                         ret);
 349                 goto out_free_cpufreq_table;
 350         }
 351
 352         /* Support turbo/boost mode */
 353         if (policy_has_boost_freq(policy)) {
 354                 /* This gets disabled by core on driver unregister */
 355                 ret = cpufreq_enable_boost_support();
 356                 if (ret)
 357                         goto out_free_cpufreq_table;
 358                 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
 359         }
 360
 361         policy->cpuinfo.transition_latency = transition_latency;
 362
 363         of_node_put(np);
 364
 365         return 0;
 366
 367 out_free_cpufreq_table:
 368         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 369 out_free_priv:
 370         kfree(priv);
 371 out_free_opp:
 372         dev_pm_opp_of_cpumask_remove_table(policy->cpus);
 373 out_node_put:
 374         of_node_put(np);
 375 out_put_reg_clk:
 376         clk_put(cpu_clk);
 377         if (!IS_ERR(cpu_reg))
 378                 regulator_put(cpu_reg);
 379
 380         return ret;
 381 }
 382
 383 static int cpufreq_exit(struct cpufreq_policy *policy)
 384 {
 385         struct private_data *priv = policy->driver_data;
 386
 387         cpufreq_cooling_unregister(priv->cdev);
 388         dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
 389         dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
 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");