drivers/cpufreq/cpufreq-dt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2012 Freescale Semiconductor, Inc.
   4  *
   5  * Copyright (C) 2014 Linaro.
   6  * Viresh Kumar <viresh.kumar@linaro.org>
   7  */
   8
   9 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
  10
  11 #include <linux/clk.h>
  12 #include <linux/cpu.h>
  13 #include <linux/cpufreq.h>
  14 #include <linux/cpumask.h>
  15 #include <linux/err.h>
  16 #include <linux/module.h>
  17 #include <linux/of.h>
  18 #include <linux/pm_opp.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/regulator/consumer.h>
  21 #include <linux/slab.h>
  22 #include <linux/thermal.h>
  23
  24 #include "cpufreq-dt.h"
  25
  26 struct private_data {
  27         struct opp_table *opp_table;
  28         struct device *cpu_dev;
  29         const char *reg_name;
  30         bool have_static_opps;
  31 };
  32
  33 static struct freq_attr *cpufreq_dt_attr[] = {
  34         &cpufreq_freq_attr_scaling_available_freqs,
  35         NULL,   /* Extra space for boost-attr if required */
  36         NULL,
  37 };
  38
  39 static int set_target(struct cpufreq_policy *policy, unsigned int index)
  40 {
  41         struct private_data *priv = policy->driver_data;
  42         unsigned long freq = policy->freq_table[index].frequency;
  43
  44         return dev_pm_opp_set_rate(priv->cpu_dev, freq * 1000);
  45 }
  46
  47 /*
  48  * An earlier version of opp-v1 bindings used to name the regulator
  49  * "cpu0-supply", we still need to handle that for backwards compatibility.
  50  */
  51 static const char *find_supply_name(struct device *dev)
  52 {
  53         struct device_node *np;
  54         struct property *pp;
  55         int cpu = dev->id;
  56         const char *name = NULL;
  57
  58         np = of_node_get(dev->of_node);
  59
  60         /* This must be valid for sure */
  61         if (WARN_ON(!np))
  62                 return NULL;
  63
  64         /* Try "cpu0" for older DTs */
  65         if (!cpu) {
  66                 pp = of_find_property(np, "cpu0-supply", NULL);
  67                 if (pp) {
  68                         name = "cpu0";
  69                         goto node_put;
  70                 }
  71         }
  72
  73         pp = of_find_property(np, "cpu-supply", NULL);
  74         if (pp) {
  75                 name = "cpu";
  76                 goto node_put;
  77         }
  78
  79         dev_dbg(dev, "no regulator for cpu%d\n", cpu);
  80 node_put:
  81         of_node_put(np);
  82         return name;
  83 }
  84
  85 static int resources_available(void)
  86 {
  87         struct device *cpu_dev;
  88         struct regulator *cpu_reg;
  89         struct clk *cpu_clk;
  90         int ret = 0;
  91         const char *name;
  92
  93         cpu_dev = get_cpu_device(0);
  94         if (!cpu_dev) {
  95                 pr_err("failed to get cpu0 device\n");
  96                 return -ENODEV;
  97         }
  98
  99         cpu_clk = clk_get(cpu_dev, NULL);
 100         ret = PTR_ERR_OR_ZERO(cpu_clk);
 101         if (ret) {
 102                 /*
 103                  * If cpu's clk node is present, but clock is not yet
 104                  * registered, we should try defering probe.
 105                  */
 106                 if (ret == -EPROBE_DEFER)
 107                         dev_dbg(cpu_dev, "clock not ready, retry\n");
 108                 else
 109                         dev_err(cpu_dev, "failed to get clock: %d\n", ret);
 110
 111                 return ret;
 112         }
 113
 114         clk_put(cpu_clk);
 115
 116         ret = dev_pm_opp_of_find_icc_paths(cpu_dev, NULL);
 117         if (ret)
 118                 return ret;
 119
 120         name = find_supply_name(cpu_dev);
 121         /* Platform doesn't require regulator */
 122         if (!name)
 123                 return 0;
 124
 125         cpu_reg = regulator_get_optional(cpu_dev, name);
 126         ret = PTR_ERR_OR_ZERO(cpu_reg);
 127         if (ret) {
 128                 /*
 129                  * If cpu's regulator supply node is present, but regulator is
 130                  * not yet registered, we should try defering probe.
 131                  */
 132                 if (ret == -EPROBE_DEFER)
 133                         dev_dbg(cpu_dev, "cpu0 regulator not ready, retry\n");
 134                 else
 135                         dev_dbg(cpu_dev, "no regulator for cpu0: %d\n", ret);
 136
 137                 return ret;
 138         }
 139
 140         regulator_put(cpu_reg);
 141         return 0;
 142 }
 143
 144 static int cpufreq_init(struct cpufreq_policy *policy)
 145 {
 146         struct cpufreq_frequency_table *freq_table;
 147         struct opp_table *opp_table = NULL;
 148         struct private_data *priv;
 149         struct device *cpu_dev;
 150         struct clk *cpu_clk;
 151         unsigned int transition_latency;
 152         bool fallback = false;
 153         const char *name;
 154         int ret;
 155
 156         cpu_dev = get_cpu_device(policy->cpu);
 157         if (!cpu_dev) {
 158                 pr_err("failed to get cpu%d device\n", policy->cpu);
 159                 return -ENODEV;
 160         }
 161
 162         cpu_clk = clk_get(cpu_dev, NULL);
 163         if (IS_ERR(cpu_clk)) {
 164                 ret = PTR_ERR(cpu_clk);
 165                 dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret);
 166                 return ret;
 167         }
 168
 169         /* Get OPP-sharing information from "operating-points-v2" bindings */
 170         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus);
 171         if (ret) {
 172                 if (ret != -ENOENT)
 173                         goto out_put_clk;
 174
 175                 /*
 176                  * operating-points-v2 not supported, fallback to old method of
 177                  * finding shared-OPPs for backward compatibility if the
 178                  * platform hasn't set sharing CPUs.
 179                  */
 180                 if (dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus))
 181                         fallback = true;
 182         }
 183
 184         /*
 185          * OPP layer will be taking care of regulators now, but it needs to know
 186          * the name of the regulator first.
 187          */
 188         name = find_supply_name(cpu_dev);
 189         if (name) {
 190                 opp_table = dev_pm_opp_set_regulators(cpu_dev, &name, 1);
 191                 if (IS_ERR(opp_table)) {
 192                         ret = PTR_ERR(opp_table);
 193                         dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n",
 194                                 policy->cpu, ret);
 195                         goto out_put_clk;
 196                 }
 197         }
 198
 199         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 200         if (!priv) {
 201                 ret = -ENOMEM;
 202                 goto out_put_regulator;
 203         }
 204
 205         priv->reg_name = name;
 206         priv->opp_table = opp_table;
 207
 208         /*
 209          * Initialize OPP tables for all policy->cpus. They will be shared by
 210          * all CPUs which have marked their CPUs shared with OPP bindings.
 211          *
 212          * For platforms not using operating-points-v2 bindings, we do this
 213          * before updating policy->cpus. Otherwise, we will end up creating
 214          * duplicate OPPs for policy->cpus.
 215          *
 216          * OPPs might be populated at runtime, don't check for error here
 217          */
 218         if (!dev_pm_opp_of_cpumask_add_table(policy->cpus))
 219                 priv->have_static_opps = true;
 220
 221         /*
 222          * But we need OPP table to function so if it is not there let's
 223          * give platform code chance to provide it for us.
 224          */
 225         ret = dev_pm_opp_get_opp_count(cpu_dev);
 226         if (ret <= 0) {
 227                 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
 228                 ret = -EPROBE_DEFER;
 229                 goto out_free_opp;
 230         }
 231
 232         if (fallback) {
 233                 cpumask_setall(policy->cpus);
 234
 235                 /*
 236                  * OPP tables are initialized only for policy->cpu, do it for
 237                  * others as well.
 238                  */
 239                 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
 240                 if (ret)
 241                         dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 242                                 __func__, ret);
 243         }
 244
 245         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 246         if (ret) {
 247                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 248                 goto out_free_opp;
 249         }
 250
 251         priv->cpu_dev = cpu_dev;
 252         policy->driver_data = priv;
 253         policy->clk = cpu_clk;
 254         policy->freq_table = freq_table;
 255
 256         policy->suspend_freq = dev_pm_opp_get_suspend_opp_freq(cpu_dev) / 1000;
 257
 258         /* Support turbo/boost mode */
 259         if (policy_has_boost_freq(policy)) {
 260                 /* This gets disabled by core on driver unregister */
 261                 ret = cpufreq_enable_boost_support();
 262                 if (ret)
 263                         goto out_free_cpufreq_table;
 264                 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
 265         }
 266
 267         transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
 268         if (!transition_latency)
 269                 transition_latency = CPUFREQ_ETERNAL;
 270
 271         policy->cpuinfo.transition_latency = transition_latency;
 272         policy->dvfs_possible_from_any_cpu = true;
 273
 274         dev_pm_opp_of_register_em(cpu_dev, policy->cpus);
 275
 276         return 0;
 277
 278 out_free_cpufreq_table:
 279         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 280 out_free_opp:
 281         if (priv->have_static_opps)
 282                 dev_pm_opp_of_cpumask_remove_table(policy->cpus);
 283         kfree(priv);
 284 out_put_regulator:
 285         if (name)
 286                 dev_pm_opp_put_regulators(opp_table);
 287 out_put_clk:
 288         clk_put(cpu_clk);
 289
 290         return ret;
 291 }
 292
 293 static int cpufreq_online(struct cpufreq_policy *policy)
 294 {
 295         /* We did light-weight tear down earlier, nothing to do here */
 296         return 0;
 297 }
 298
 299 static int cpufreq_offline(struct cpufreq_policy *policy)
 300 {
 301         /*
 302          * Preserve policy->driver_data and don't free resources on light-weight
 303          * tear down.
 304          */
 305         return 0;
 306 }
 307
 308 static int cpufreq_exit(struct cpufreq_policy *policy)
 309 {
 310         struct private_data *priv = policy->driver_data;
 311
 312         dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
 313         if (priv->have_static_opps)
 314                 dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
 315         if (priv->reg_name)
 316                 dev_pm_opp_put_regulators(priv->opp_table);
 317
 318         clk_put(policy->clk);
 319         kfree(priv);
 320
 321         return 0;
 322 }
 323
 324 static struct cpufreq_driver dt_cpufreq_driver = {
 325         .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK |
 326                  CPUFREQ_IS_COOLING_DEV,
 327         .verify = cpufreq_generic_frequency_table_verify,
 328         .target_index = set_target,
 329         .get = cpufreq_generic_get,
 330         .init = cpufreq_init,
 331         .exit = cpufreq_exit,
 332         .online = cpufreq_online,
 333         .offline = cpufreq_offline,
 334         .name = "cpufreq-dt",
 335         .attr = cpufreq_dt_attr,
 336         .suspend = cpufreq_generic_suspend,
 337 };
 338
 339 static int dt_cpufreq_probe(struct platform_device *pdev)
 340 {
 341         struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev);
 342         int ret;
 343
 344         /*
 345          * All per-cluster (CPUs sharing clock/voltages) initialization is done
 346          * from ->init(). In probe(), we just need to make sure that clk and
 347          * regulators are available. Else defer probe and retry.
 348          *
 349          * FIXME: Is checking this only for CPU0 sufficient ?
 350          */
 351         ret = resources_available();
 352         if (ret)
 353                 return ret;
 354
 355         if (data) {
 356                 if (data->have_governor_per_policy)
 357                         dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY;
 358
 359                 dt_cpufreq_driver.resume = data->resume;
 360                 if (data->suspend)
 361                         dt_cpufreq_driver.suspend = data->suspend;
 362                 if (data->get_intermediate) {
 363                         dt_cpufreq_driver.target_intermediate = data->target_intermediate;
 364                         dt_cpufreq_driver.get_intermediate = data->get_intermediate;
 365                 }
 366         }
 367
 368         ret = cpufreq_register_driver(&dt_cpufreq_driver);
 369         if (ret)
 370                 dev_err(&pdev->dev, "failed register driver: %d\n", ret);
 371
 372         return ret;
 373 }
 374
 375 static int dt_cpufreq_remove(struct platform_device *pdev)
 376 {
 377         cpufreq_unregister_driver(&dt_cpufreq_driver);
 378         return 0;
 379 }
 380
 381 static struct platform_driver dt_cpufreq_platdrv = {
 382         .driver = {
 383                 .name   = "cpufreq-dt",
 384         },
 385         .probe          = dt_cpufreq_probe,
 386         .remove         = dt_cpufreq_remove,
 387 };
 388 module_platform_driver(dt_cpufreq_platdrv);
 389
 390 MODULE_ALIAS("platform:cpufreq-dt");
 391 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 392 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 393 MODULE_DESCRIPTION("Generic cpufreq driver");
 394 MODULE_LICENSE("GPL");