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 thermal_cooling_device *cdev;
  35         const char *reg_name;
  36 };
  37
  38 static struct freq_attr *cpufreq_dt_attr[] = {
  39         &cpufreq_freq_attr_scaling_available_freqs,
  40         NULL,   /* Extra space for boost-attr if required */
  41         NULL,
  42 };
  43
  44 static int set_target(struct cpufreq_policy *policy, unsigned int index)
  45 {
  46         struct private_data *priv = policy->driver_data;
  47
  48         return dev_pm_opp_set_rate(priv->cpu_dev,
  49                                    policy->freq_table[index].frequency * 1000);
  50 }
  51
  52 /*
  53  * An earlier version of opp-v1 bindings used to name the regulator
  54  * "cpu0-supply", we still need to handle that for backwards compatibility.
  55  */
  56 static const char *find_supply_name(struct device *dev)
  57 {
  58         struct device_node *np;
  59         struct property *pp;
  60         int cpu = dev->id;
  61         const char *name = NULL;
  62
  63         np = of_node_get(dev->of_node);
  64
  65         /* This must be valid for sure */
  66         if (WARN_ON(!np))
  67                 return NULL;
  68
  69         /* Try "cpu0" for older DTs */
  70         if (!cpu) {
  71                 pp = of_find_property(np, "cpu0-supply", NULL);
  72                 if (pp) {
  73                         name = "cpu0";
  74                         goto node_put;
  75                 }
  76         }
  77
  78         pp = of_find_property(np, "cpu-supply", NULL);
  79         if (pp) {
  80                 name = "cpu";
  81                 goto node_put;
  82         }
  83
  84         dev_dbg(dev, "no regulator for cpu%d\n", cpu);
  85 node_put:
  86         of_node_put(np);
  87         return name;
  88 }
  89
  90 static int resources_available(void)
  91 {
  92         struct device *cpu_dev;
  93         struct regulator *cpu_reg;
  94         struct clk *cpu_clk;
  95         int ret = 0;
  96         const char *name;
  97
  98         cpu_dev = get_cpu_device(0);
  99         if (!cpu_dev) {
 100                 pr_err("failed to get cpu0 device\n");
 101                 return -ENODEV;
 102         }
 103
 104         cpu_clk = clk_get(cpu_dev, NULL);
 105         ret = PTR_ERR_OR_ZERO(cpu_clk);
 106         if (ret) {
 107                 /*
 108                  * If cpu's clk node is present, but clock is not yet
 109                  * registered, we should try defering probe.
 110                  */
 111                 if (ret == -EPROBE_DEFER)
 112                         dev_dbg(cpu_dev, "clock not ready, retry\n");
 113                 else
 114                         dev_err(cpu_dev, "failed to get clock: %d\n", ret);
 115
 116                 return ret;
 117         }
 118
 119         clk_put(cpu_clk);
 120
 121         name = find_supply_name(cpu_dev);
 122         /* Platform doesn't require regulator */
 123         if (!name)
 124                 return 0;
 125
 126         cpu_reg = regulator_get_optional(cpu_dev, name);
 127         ret = PTR_ERR_OR_ZERO(cpu_reg);
 128         if (ret) {
 129                 /*
 130                  * If cpu's regulator supply node is present, but regulator is
 131                  * not yet registered, we should try defering probe.
 132                  */
 133                 if (ret == -EPROBE_DEFER)
 134                         dev_dbg(cpu_dev, "cpu0 regulator not ready, retry\n");
 135                 else
 136                         dev_dbg(cpu_dev, "no regulator for cpu0: %d\n", ret);
 137
 138                 return ret;
 139         }
 140
 141         regulator_put(cpu_reg);
 142         return 0;
 143 }
 144
 145 static int cpufreq_init(struct cpufreq_policy *policy)
 146 {
 147         struct cpufreq_frequency_table *freq_table;
 148         struct private_data *priv;
 149         struct device *cpu_dev;
 150         struct clk *cpu_clk;
 151         struct dev_pm_opp *suspend_opp;
 152 #ifdef CONFIG_ARCH_ROCKCHIP
 153         struct cpumask cpus;
 154 #endif
 155         unsigned int transition_latency;
 156         bool opp_v1 = false;
 157         const char *name;
 158         int ret;
 159
 160         cpu_dev = get_cpu_device(policy->cpu);
 161         if (!cpu_dev) {
 162                 pr_err("failed to get cpu%d device\n", policy->cpu);
 163                 return -ENODEV;
 164         }
 165
 166         cpu_clk = clk_get(cpu_dev, NULL);
 167         if (IS_ERR(cpu_clk)) {
 168                 ret = PTR_ERR(cpu_clk);
 169                 dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret);
 170                 return ret;
 171         }
 172
 173         /* Get OPP-sharing information from "operating-points-v2" bindings */
 174         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus);
 175         if (ret) {
 176                 /*
 177                  * operating-points-v2 not supported, fallback to old method of
 178                  * finding shared-OPPs for backward compatibility.
 179                  */
 180                 if (ret == -ENOENT)
 181                         opp_v1 = true;
 182                 else
 183                         goto out_put_clk;
 184         }
 185
 186         /*
 187          * OPP layer will be taking care of regulators now, but it needs to know
 188          * the name of the regulator first.
 189          */
 190         name = find_supply_name(cpu_dev);
 191         if (name) {
 192                 ret = dev_pm_opp_set_regulator(cpu_dev, name);
 193                 if (ret) {
 194                         dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n",
 195                                 policy->cpu, ret);
 196                         goto out_put_clk;
 197                 }
 198         }
 199
 200         /*
 201          * Initialize OPP tables for all policy->cpus. They will be shared by
 202          * all CPUs which have marked their CPUs shared with OPP bindings.
 203          *
 204          * For platforms not using operating-points-v2 bindings, we do this
 205          * before updating policy->cpus. Otherwise, we will end up creating
 206          * duplicate OPPs for policy->cpus.
 207          *
 208          * OPPs might be populated at runtime, don't check for error here
 209          */
 210 #ifdef CONFIG_ARCH_ROCKCHIP
 211         ret = dev_pm_opp_of_add_table(cpu_dev);
 212         if (ret) {
 213                 dev_err(cpu_dev, "couldn't find opp table for cpu:%d, %d\n",
 214                         policy->cpu, ret);
 215         } else {
 216                 cpumask_copy(&cpus, policy->cpus);
 217                 cpumask_clear_cpu(policy->cpu, &cpus);
 218                 if (!cpumask_empty(&cpus)) {
 219                         if (dev_pm_opp_of_cpumask_add_table(&cpus))
 220                                 dev_pm_opp_of_remove_table(cpu_dev);
 221                 }
 222         }
 223 #else
 224         dev_pm_opp_of_cpumask_add_table(policy->cpus);
 225 #endif
 226
 227         /*
 228          * But we need OPP table to function so if it is not there let's
 229          * give platform code chance to provide it for us.
 230          */
 231         ret = dev_pm_opp_get_opp_count(cpu_dev);
 232         if (ret <= 0) {
 233                 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
 234                 ret = -EPROBE_DEFER;
 235                 goto out_free_opp;
 236         }
 237
 238         if (opp_v1) {
 239                 struct cpufreq_dt_platform_data *pd = cpufreq_get_driver_data();
 240
 241                 if (!pd || !pd->independent_clocks)
 242                         cpumask_setall(policy->cpus);
 243
 244                 /*
 245                  * OPP tables are initialized only for policy->cpu, do it for
 246                  * others as well.
 247                  */
 248                 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
 249                 if (ret)
 250                         dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 251                                 __func__, ret);
 252         }
 253
 254         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 255         if (!priv) {
 256                 ret = -ENOMEM;
 257                 goto out_free_opp;
 258         }
 259
 260         priv->reg_name = name;
 261
 262         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 263         if (ret) {
 264                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 265                 goto out_free_priv;
 266         }
 267
 268         priv->cpu_dev = cpu_dev;
 269         policy->driver_data = priv;
 270         policy->clk = cpu_clk;
 271
 272         rcu_read_lock();
 273         suspend_opp = dev_pm_opp_get_suspend_opp(cpu_dev);
 274         if (suspend_opp)
 275                 policy->suspend_freq = dev_pm_opp_get_freq(suspend_opp) / 1000;
 276         rcu_read_unlock();
 277
 278         ret = cpufreq_table_validate_and_show(policy, freq_table);
 279         if (ret) {
 280                 dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
 281                         ret);
 282                 goto out_free_cpufreq_table;
 283         }
 284
 285         /* Support turbo/boost mode */
 286         if (policy_has_boost_freq(policy)) {
 287                 /* This gets disabled by core on driver unregister */
 288                 ret = cpufreq_enable_boost_support();
 289                 if (ret)
 290                         goto out_free_cpufreq_table;
 291                 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
 292         }
 293
 294         transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
 295         if (!transition_latency)
 296                 transition_latency = CPUFREQ_ETERNAL;
 297
 298         policy->cpuinfo.transition_latency = transition_latency;
 299
 300         return 0;
 301
 302 out_free_cpufreq_table:
 303         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 304 out_free_priv:
 305         kfree(priv);
 306 out_free_opp:
 307         dev_pm_opp_of_cpumask_remove_table(policy->cpus);
 308         if (name)
 309                 dev_pm_opp_put_regulator(cpu_dev);
 310 out_put_clk:
 311         clk_put(cpu_clk);
 312
 313         return ret;
 314 }
 315
 316 static int cpufreq_exit(struct cpufreq_policy *policy)
 317 {
 318         struct cpumask cpus;
 319         struct private_data *priv = policy->driver_data;
 320
 321 #ifdef CONFIG_ARCH_ROCKCHIP
 322         cpumask_set_cpu(policy->cpu, policy->cpus);
 323         if (cpufreq_generic_suspend(policy))
 324                 pr_err("%s: Failed to suspend driver: %p\n", __func__, policy);
 325         cpumask_clear_cpu(policy->cpu, policy->cpus);
 326 #endif
 327         priv->cpu_dev = get_cpu_device(policy->cpu);
 328         cpufreq_cooling_unregister(priv->cdev);
 329         dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
 330         cpumask_copy(&cpus, policy->related_cpus);
 331         cpumask_clear_cpu(policy->cpu, &cpus);
 332         dev_pm_opp_of_cpumask_remove_table(&cpus);
 333         dev_pm_opp_of_remove_table(priv->cpu_dev);
 334         if (priv->reg_name)
 335                 dev_pm_opp_put_regulator(priv->cpu_dev);
 336
 337         clk_put(policy->clk);
 338         kfree(priv);
 339
 340         return 0;
 341 }
 342
 343 static void cpufreq_ready(struct cpufreq_policy *policy)
 344 {
 345         struct private_data *priv = policy->driver_data;
 346         struct device_node *np = of_node_get(priv->cpu_dev->of_node);
 347
 348         if (WARN_ON(!np))
 349                 return;
 350
 351         /*
 352          * For now, just loading the cooling device;
 353          * thermal DT code takes care of matching them.
 354          */
 355         if (of_find_property(np, "#cooling-cells", NULL)) {
 356                 u32 power_coefficient = 0;
 357
 358                 of_property_read_u32(np, "dynamic-power-coefficient",
 359                                      &power_coefficient);
 360
 361                 priv->cdev = of_cpufreq_power_cooling_register(np,
 362                                 policy->related_cpus, power_coefficient, NULL);
 363                 if (IS_ERR(priv->cdev)) {
 364                         dev_err(priv->cpu_dev,
 365                                 "running cpufreq without cooling device: %ld\n",
 366                                 PTR_ERR(priv->cdev));
 367
 368                         priv->cdev = NULL;
 369                 }
 370         }
 371
 372         of_node_put(np);
 373 }
 374
 375 static struct cpufreq_driver dt_cpufreq_driver = {
 376 #ifdef CONFIG_ARCH_ROCKCHIP
 377         .flags = CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY,
 378 #else
 379         .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 380 #endif
 381         .verify = cpufreq_generic_frequency_table_verify,
 382         .target_index = set_target,
 383         .get = cpufreq_generic_get,
 384         .init = cpufreq_init,
 385         .exit = cpufreq_exit,
 386         .ready = cpufreq_ready,
 387         .name = "cpufreq-dt",
 388         .attr = cpufreq_dt_attr,
 389         .suspend = cpufreq_generic_suspend,
 390 };
 391
 392 static int dt_cpufreq_probe(struct platform_device *pdev)
 393 {
 394         int ret;
 395
 396         /*
 397          * All per-cluster (CPUs sharing clock/voltages) initialization is done
 398          * from ->init(). In probe(), we just need to make sure that clk and
 399          * regulators are available. Else defer probe and retry.
 400          *
 401          * FIXME: Is checking this only for CPU0 sufficient ?
 402          */
 403         ret = resources_available();
 404         if (ret)
 405                 return ret;
 406
 407         dt_cpufreq_driver.driver_data = dev_get_platdata(&pdev->dev);
 408
 409         ret = cpufreq_register_driver(&dt_cpufreq_driver);
 410         if (ret)
 411                 dev_err(&pdev->dev, "failed register driver: %d\n", ret);
 412
 413         return ret;
 414 }
 415
 416 static int dt_cpufreq_remove(struct platform_device *pdev)
 417 {
 418         cpufreq_unregister_driver(&dt_cpufreq_driver);
 419         return 0;
 420 }
 421
 422 static struct platform_driver dt_cpufreq_platdrv = {
 423         .driver = {
 424                 .name   = "cpufreq-dt",
 425         },
 426         .probe          = dt_cpufreq_probe,
 427         .remove         = dt_cpufreq_remove,
 428 };
 429 module_platform_driver(dt_cpufreq_platdrv);
 430
 431 MODULE_ALIAS("platform:cpufreq-dt");
 432 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 433 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 434 MODULE_DESCRIPTION("Generic cpufreq driver");
 435 MODULE_LICENSE("GPL");