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