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/list.h>
  17 #include <linux/module.h>
  18 #include <linux/of.h>
  19 #include <linux/pm_opp.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/regulator/consumer.h>
  22 #include <linux/slab.h>
  23 #include <linux/thermal.h>
  24
  25 #include "cpufreq-dt.h"
  26
  27 struct private_data {
  28         struct list_head node;
  29
  30         cpumask_var_t cpus;
  31         struct device *cpu_dev;
  32         struct opp_table *opp_table;
  33         struct opp_table *reg_opp_table;
  34         bool have_static_opps;
  35 };
  36
  37 static LIST_HEAD(priv_list);
  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 struct private_data *cpufreq_dt_find_data(int cpu)
  46 {
  47         struct private_data *priv;
  48
  49         list_for_each_entry(priv, &priv_list, node) {
  50                 if (cpumask_test_cpu(cpu, priv->cpus))
  51                         return priv;
  52         }
  53
  54         return NULL;
  55 }
  56
  57 static int set_target(struct cpufreq_policy *policy, unsigned int index)
  58 {
  59         struct private_data *priv = policy->driver_data;
  60         unsigned long freq = policy->freq_table[index].frequency;
  61
  62         return dev_pm_opp_set_rate(priv->cpu_dev, freq * 1000);
  63 }
  64
  65 /*
  66  * An earlier version of opp-v1 bindings used to name the regulator
  67  * "cpu0-supply", we still need to handle that for backwards compatibility.
  68  */
  69 static const char *find_supply_name(struct device *dev)
  70 {
  71         struct device_node *np;
  72         struct property *pp;
  73         int cpu = dev->id;
  74         const char *name = NULL;
  75
  76         np = of_node_get(dev->of_node);
  77
  78         /* This must be valid for sure */
  79         if (WARN_ON(!np))
  80                 return NULL;
  81
  82         /* Try "cpu0" for older DTs */
  83         if (!cpu) {
  84                 pp = of_find_property(np, "cpu0-supply", NULL);
  85                 if (pp) {
  86                         name = "cpu0";
  87                         goto node_put;
  88                 }
  89         }
  90
  91         pp = of_find_property(np, "cpu-supply", NULL);
  92         if (pp) {
  93                 name = "cpu";
  94                 goto node_put;
  95         }
  96
  97         dev_dbg(dev, "no regulator for cpu%d\n", cpu);
  98 node_put:
  99         of_node_put(np);
 100         return name;
 101 }
 102
 103 static int cpufreq_init(struct cpufreq_policy *policy)
 104 {
 105         struct cpufreq_frequency_table *freq_table;
 106         struct private_data *priv;
 107         struct device *cpu_dev;
 108         struct clk *cpu_clk;
 109         unsigned int transition_latency;
 110         int ret;
 111
 112         priv = cpufreq_dt_find_data(policy->cpu);
 113         if (!priv) {
 114                 pr_err("failed to find data for cpu%d\n", policy->cpu);
 115                 return -ENODEV;
 116         }
 117
 118         cpu_dev = priv->cpu_dev;
 119         cpumask_copy(policy->cpus, priv->cpus);
 120
 121         cpu_clk = clk_get(cpu_dev, NULL);
 122         if (IS_ERR(cpu_clk)) {
 123                 ret = PTR_ERR(cpu_clk);
 124                 dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret);
 125                 return ret;
 126         }
 127
 128         /*
 129          * Initialize OPP tables for all policy->cpus. They will be shared by
 130          * all CPUs which have marked their CPUs shared with OPP bindings.
 131          *
 132          * For platforms not using operating-points-v2 bindings, we do this
 133          * before updating policy->cpus. Otherwise, we will end up creating
 134          * duplicate OPPs for policy->cpus.
 135          *
 136          * OPPs might be populated at runtime, don't check for error here
 137          */
 138         if (!dev_pm_opp_of_cpumask_add_table(policy->cpus))
 139                 priv->have_static_opps = true;
 140
 141         /*
 142          * But we need OPP table to function so if it is not there let's
 143          * give platform code chance to provide it for us.
 144          */
 145         ret = dev_pm_opp_get_opp_count(cpu_dev);
 146         if (ret <= 0) {
 147                 dev_err(cpu_dev, "OPP table can't be empty\n");
 148                 ret = -ENODEV;
 149                 goto out_free_opp;
 150         }
 151
 152         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 153         if (ret) {
 154                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 155                 goto out_free_opp;
 156         }
 157
 158         policy->driver_data = priv;
 159         policy->clk = cpu_clk;
 160         policy->freq_table = freq_table;
 161
 162         policy->suspend_freq = dev_pm_opp_get_suspend_opp_freq(cpu_dev) / 1000;
 163
 164         /* Support turbo/boost mode */
 165         if (policy_has_boost_freq(policy)) {
 166                 /* This gets disabled by core on driver unregister */
 167                 ret = cpufreq_enable_boost_support();
 168                 if (ret)
 169                         goto out_free_cpufreq_table;
 170                 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
 171         }
 172
 173         transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
 174         if (!transition_latency)
 175                 transition_latency = CPUFREQ_ETERNAL;
 176
 177         policy->cpuinfo.transition_latency = transition_latency;
 178         policy->dvfs_possible_from_any_cpu = true;
 179
 180         dev_pm_opp_of_register_em(cpu_dev, policy->cpus);
 181
 182         return 0;
 183
 184 out_free_cpufreq_table:
 185         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 186 out_free_opp:
 187         if (priv->have_static_opps)
 188                 dev_pm_opp_of_cpumask_remove_table(policy->cpus);
 189         clk_put(cpu_clk);
 190
 191         return ret;
 192 }
 193
 194 static int cpufreq_online(struct cpufreq_policy *policy)
 195 {
 196         /* We did light-weight tear down earlier, nothing to do here */
 197         return 0;
 198 }
 199
 200 static int cpufreq_offline(struct cpufreq_policy *policy)
 201 {
 202         /*
 203          * Preserve policy->driver_data and don't free resources on light-weight
 204          * tear down.
 205          */
 206         return 0;
 207 }
 208
 209 static int cpufreq_exit(struct cpufreq_policy *policy)
 210 {
 211         struct private_data *priv = policy->driver_data;
 212
 213         dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
 214         if (priv->have_static_opps)
 215                 dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
 216         clk_put(policy->clk);
 217         return 0;
 218 }
 219
 220 static struct cpufreq_driver dt_cpufreq_driver = {
 221         .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK |
 222                  CPUFREQ_IS_COOLING_DEV,
 223         .verify = cpufreq_generic_frequency_table_verify,
 224         .target_index = set_target,
 225         .get = cpufreq_generic_get,
 226         .init = cpufreq_init,
 227         .exit = cpufreq_exit,
 228         .online = cpufreq_online,
 229         .offline = cpufreq_offline,
 230         .name = "cpufreq-dt",
 231         .attr = cpufreq_dt_attr,
 232         .suspend = cpufreq_generic_suspend,
 233 };
 234
 235 static int dt_cpufreq_early_init(struct device *dev, int cpu)
 236 {
 237         struct private_data *priv;
 238         struct device *cpu_dev;
 239         const char *reg_name;
 240         int ret;
 241
 242         /* Check if this CPU is already covered by some other policy */
 243         if (cpufreq_dt_find_data(cpu))
 244                 return 0;
 245
 246         cpu_dev = get_cpu_device(cpu);
 247         if (!cpu_dev)
 248                 return -EPROBE_DEFER;
 249
 250         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 251         if (!priv)
 252                 return -ENOMEM;
 253
 254         if (!alloc_cpumask_var(&priv->cpus, GFP_KERNEL))
 255                 return -ENOMEM;
 256
 257         priv->cpu_dev = cpu_dev;
 258
 259         /* Try to get OPP table early to ensure resources are available */
 260         priv->opp_table = dev_pm_opp_get_opp_table(cpu_dev);
 261         if (IS_ERR(priv->opp_table)) {
 262                 ret = PTR_ERR(priv->opp_table);
 263                 if (ret != -EPROBE_DEFER)
 264                         dev_err(cpu_dev, "failed to get OPP table: %d\n", ret);
 265                 goto free_cpumask;
 266         }
 267
 268         /*
 269          * OPP layer will be taking care of regulators now, but it needs to know
 270          * the name of the regulator first.
 271          */
 272         reg_name = find_supply_name(cpu_dev);
 273         if (reg_name) {
 274                 priv->reg_opp_table = dev_pm_opp_set_regulators(cpu_dev,
 275                                                                 &reg_name, 1);
 276                 if (IS_ERR(priv->reg_opp_table)) {
 277                         ret = PTR_ERR(priv->reg_opp_table);
 278                         if (ret != -EPROBE_DEFER)
 279                                 dev_err(cpu_dev, "failed to set regulators: %d\n",
 280                                         ret);
 281                         goto put_table;
 282                 }
 283         }
 284
 285         /* Find OPP sharing information so we can fill pri->cpus here */
 286         /* Get OPP-sharing information from "operating-points-v2" bindings */
 287         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->cpus);
 288         if (ret) {
 289                 if (ret != -ENOENT)
 290                         goto put_reg;
 291
 292                 /*
 293                  * operating-points-v2 not supported, fallback to all CPUs share
 294                  * OPP for backward compatibility if the platform hasn't set
 295                  * sharing CPUs.
 296                  */
 297                 if (dev_pm_opp_get_sharing_cpus(cpu_dev, priv->cpus)) {
 298                         cpumask_setall(priv->cpus);
 299
 300                         /*
 301                          * OPP tables are initialized only for cpu, do it for
 302                          * others as well.
 303                          */
 304                         ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->cpus);
 305                         if (ret)
 306                                 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 307                                         __func__, ret);
 308                 }
 309         }
 310
 311         list_add(&priv->node, &priv_list);
 312         return 0;
 313
 314 put_reg:
 315         if (priv->reg_opp_table)
 316                 dev_pm_opp_put_regulators(priv->reg_opp_table);
 317 put_table:
 318         dev_pm_opp_put_opp_table(priv->opp_table);
 319 free_cpumask:
 320         free_cpumask_var(priv->cpus);
 321         return ret;
 322 }
 323
 324 static void dt_cpufreq_release(void)
 325 {
 326         struct private_data *priv, *tmp;
 327
 328         list_for_each_entry_safe(priv, tmp, &priv_list, node) {
 329                 if (priv->reg_opp_table)
 330                         dev_pm_opp_put_regulators(priv->reg_opp_table);
 331                 dev_pm_opp_put_opp_table(priv->opp_table);
 332                 free_cpumask_var(priv->cpus);
 333                 list_del(&priv->node);
 334         }
 335 }
 336
 337 static int dt_cpufreq_probe(struct platform_device *pdev)
 338 {
 339         struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev);
 340         int ret, cpu;
 341
 342         /* Request resources early so we can return in case of -EPROBE_DEFER */
 343         for_each_possible_cpu(cpu) {
 344                 ret = dt_cpufreq_early_init(&pdev->dev, cpu);
 345                 if (ret)
 346                         goto err;
 347         }
 348
 349         if (data) {
 350                 if (data->have_governor_per_policy)
 351                         dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY;
 352
 353                 dt_cpufreq_driver.resume = data->resume;
 354                 if (data->suspend)
 355                         dt_cpufreq_driver.suspend = data->suspend;
 356                 if (data->get_intermediate) {
 357                         dt_cpufreq_driver.target_intermediate = data->target_intermediate;
 358                         dt_cpufreq_driver.get_intermediate = data->get_intermediate;
 359                 }
 360         }
 361
 362         ret = cpufreq_register_driver(&dt_cpufreq_driver);
 363         if (ret) {
 364                 dev_err(&pdev->dev, "failed register driver: %d\n", ret);
 365                 goto err;
 366         }
 367
 368         return 0;
 369 err:
 370         dt_cpufreq_release();
 371         return ret;
 372 }
 373
 374 static int dt_cpufreq_remove(struct platform_device *pdev)
 375 {
 376         cpufreq_unregister_driver(&dt_cpufreq_driver);
 377         dt_cpufreq_release();
 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");