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 <[email protected]>
   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 cpufreq_frequency_table *freq_table;
  33         bool have_static_opps;
  34         int opp_token;
  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 __free(device_node) = of_node_get(dev->of_node);
  72         struct property *pp;
  73         int cpu = dev->id;
  74
  75         /* This must be valid for sure */
  76         if (WARN_ON(!np))
  77                 return NULL;
  78
  79         /* Try "cpu0" for older DTs */
  80         if (!cpu) {
  81                 pp = of_find_property(np, "cpu0-supply", NULL);
  82                 if (pp)
  83                         return "cpu0";
  84         }
  85
  86         pp = of_find_property(np, "cpu-supply", NULL);
  87         if (pp)
  88                 return "cpu";
  89
  90         dev_dbg(dev, "no regulator for cpu%d\n", cpu);
  91         return NULL;
  92 }
  93
  94 static int cpufreq_init(struct cpufreq_policy *policy)
  95 {
  96         struct private_data *priv;
  97         struct device *cpu_dev;
  98         struct clk *cpu_clk;
  99         unsigned int transition_latency;
 100         int ret;
 101
 102         priv = cpufreq_dt_find_data(policy->cpu);
 103         if (!priv) {
 104                 pr_err("failed to find data for cpu%d\n", policy->cpu);
 105                 return -ENODEV;
 106         }
 107         cpu_dev = priv->cpu_dev;
 108
 109         cpu_clk = clk_get(cpu_dev, NULL);
 110         if (IS_ERR(cpu_clk)) {
 111                 ret = PTR_ERR(cpu_clk);
 112                 dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret);
 113                 return ret;
 114         }
 115
 116         transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
 117         if (!transition_latency)
 118                 transition_latency = CPUFREQ_ETERNAL;
 119
 120         cpumask_copy(policy->cpus, priv->cpus);
 121         policy->driver_data = priv;
 122         policy->clk = cpu_clk;
 123         policy->freq_table = priv->freq_table;
 124         policy->suspend_freq = dev_pm_opp_get_suspend_opp_freq(cpu_dev) / 1000;
 125         policy->cpuinfo.transition_latency = transition_latency;
 126         policy->dvfs_possible_from_any_cpu = true;
 127
 128         /* Support turbo/boost mode */
 129         if (policy_has_boost_freq(policy)) {
 130                 /* This gets disabled by core on driver unregister */
 131                 ret = cpufreq_enable_boost_support();
 132                 if (ret)
 133                         goto out_clk_put;
 134                 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
 135         }
 136
 137         return 0;
 138
 139 out_clk_put:
 140         clk_put(cpu_clk);
 141
 142         return ret;
 143 }
 144
 145 static int cpufreq_online(struct cpufreq_policy *policy)
 146 {
 147         /* We did light-weight tear down earlier, nothing to do here */
 148         return 0;
 149 }
 150
 151 static int cpufreq_offline(struct cpufreq_policy *policy)
 152 {
 153         /*
 154          * Preserve policy->driver_data and don't free resources on light-weight
 155          * tear down.
 156          */
 157         return 0;
 158 }
 159
 160 static void cpufreq_exit(struct cpufreq_policy *policy)
 161 {
 162         clk_put(policy->clk);
 163 }
 164
 165 static struct cpufreq_driver dt_cpufreq_driver = {
 166         .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK |
 167                  CPUFREQ_IS_COOLING_DEV,
 168         .verify = cpufreq_generic_frequency_table_verify,
 169         .target_index = set_target,
 170         .get = cpufreq_generic_get,
 171         .init = cpufreq_init,
 172         .exit = cpufreq_exit,
 173         .online = cpufreq_online,
 174         .offline = cpufreq_offline,
 175         .register_em = cpufreq_register_em_with_opp,
 176         .name = "cpufreq-dt",
 177         .attr = cpufreq_dt_attr,
 178         .suspend = cpufreq_generic_suspend,
 179 };
 180
 181 static int dt_cpufreq_early_init(struct device *dev, int cpu)
 182 {
 183         struct private_data *priv;
 184         struct device *cpu_dev;
 185         bool fallback = false;
 186         const char *reg_name[] = { NULL, NULL };
 187         int ret;
 188
 189         /* Check if this CPU is already covered by some other policy */
 190         if (cpufreq_dt_find_data(cpu))
 191                 return 0;
 192
 193         cpu_dev = get_cpu_device(cpu);
 194         if (!cpu_dev)
 195                 return -EPROBE_DEFER;
 196
 197         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 198         if (!priv)
 199                 return -ENOMEM;
 200
 201         if (!zalloc_cpumask_var(&priv->cpus, GFP_KERNEL))
 202                 return -ENOMEM;
 203
 204         cpumask_set_cpu(cpu, priv->cpus);
 205         priv->cpu_dev = cpu_dev;
 206
 207         /*
 208          * OPP layer will be taking care of regulators now, but it needs to know
 209          * the name of the regulator first.
 210          */
 211         reg_name[0] = find_supply_name(cpu_dev);
 212         if (reg_name[0]) {
 213                 priv->opp_token = dev_pm_opp_set_regulators(cpu_dev, reg_name);
 214                 if (priv->opp_token < 0) {
 215                         ret = dev_err_probe(cpu_dev, priv->opp_token,
 216                                             "failed to set regulators\n");
 217                         goto free_cpumask;
 218                 }
 219         }
 220
 221         /* Get OPP-sharing information from "operating-points-v2" bindings */
 222         ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->cpus);
 223         if (ret) {
 224                 if (ret != -ENOENT)
 225                         goto out;
 226
 227                 /*
 228                  * operating-points-v2 not supported, fallback to all CPUs share
 229                  * OPP for backward compatibility if the platform hasn't set
 230                  * sharing CPUs.
 231                  */
 232                 if (dev_pm_opp_get_sharing_cpus(cpu_dev, priv->cpus))
 233                         fallback = true;
 234         }
 235
 236         /*
 237          * Initialize OPP tables for all priv->cpus. They will be shared by
 238          * all CPUs which have marked their CPUs shared with OPP bindings.
 239          *
 240          * For platforms not using operating-points-v2 bindings, we do this
 241          * before updating priv->cpus. Otherwise, we will end up creating
 242          * duplicate OPPs for the CPUs.
 243          *
 244          * OPPs might be populated at runtime, don't fail for error here unless
 245          * it is -EPROBE_DEFER.
 246          */
 247         ret = dev_pm_opp_of_cpumask_add_table(priv->cpus);
 248         if (!ret) {
 249                 priv->have_static_opps = true;
 250         } else if (ret == -EPROBE_DEFER) {
 251                 goto out;
 252         }
 253
 254         /*
 255          * The OPP table must be initialized, statically or dynamically, by this
 256          * point.
 257          */
 258         ret = dev_pm_opp_get_opp_count(cpu_dev);
 259         if (ret <= 0) {
 260                 dev_err(cpu_dev, "OPP table can't be empty\n");
 261                 ret = -ENODEV;
 262                 goto out;
 263         }
 264
 265         if (fallback) {
 266                 cpumask_setall(priv->cpus);
 267                 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->cpus);
 268                 if (ret)
 269                         dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 270                                 __func__, ret);
 271         }
 272
 273         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &priv->freq_table);
 274         if (ret) {
 275                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 276                 goto out;
 277         }
 278
 279         list_add(&priv->node, &priv_list);
 280         return 0;
 281
 282 out:
 283         if (priv->have_static_opps)
 284                 dev_pm_opp_of_cpumask_remove_table(priv->cpus);
 285         dev_pm_opp_put_regulators(priv->opp_token);
 286 free_cpumask:
 287         free_cpumask_var(priv->cpus);
 288         return ret;
 289 }
 290
 291 static void dt_cpufreq_release(void)
 292 {
 293         struct private_data *priv, *tmp;
 294
 295         list_for_each_entry_safe(priv, tmp, &priv_list, node) {
 296                 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &priv->freq_table);
 297                 if (priv->have_static_opps)
 298                         dev_pm_opp_of_cpumask_remove_table(priv->cpus);
 299                 dev_pm_opp_put_regulators(priv->opp_token);
 300                 free_cpumask_var(priv->cpus);
 301                 list_del(&priv->node);
 302         }
 303 }
 304
 305 static int dt_cpufreq_probe(struct platform_device *pdev)
 306 {
 307         struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev);
 308         int ret, cpu;
 309
 310         /* Request resources early so we can return in case of -EPROBE_DEFER */
 311         for_each_possible_cpu(cpu) {
 312                 ret = dt_cpufreq_early_init(&pdev->dev, cpu);
 313                 if (ret)
 314                         goto err;
 315         }
 316
 317         if (data) {
 318                 if (data->have_governor_per_policy)
 319                         dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY;
 320
 321                 dt_cpufreq_driver.resume = data->resume;
 322                 if (data->suspend)
 323                         dt_cpufreq_driver.suspend = data->suspend;
 324                 if (data->get_intermediate) {
 325                         dt_cpufreq_driver.target_intermediate = data->target_intermediate;
 326                         dt_cpufreq_driver.get_intermediate = data->get_intermediate;
 327                 }
 328         }
 329
 330         ret = cpufreq_register_driver(&dt_cpufreq_driver);
 331         if (ret) {
 332                 dev_err(&pdev->dev, "failed register driver: %d\n", ret);
 333                 goto err;
 334         }
 335
 336         return 0;
 337 err:
 338         dt_cpufreq_release();
 339         return ret;
 340 }
 341
 342 static void dt_cpufreq_remove(struct platform_device *pdev)
 343 {
 344         cpufreq_unregister_driver(&dt_cpufreq_driver);
 345         dt_cpufreq_release();
 346 }
 347
 348 static struct platform_driver dt_cpufreq_platdrv = {
 349         .driver = {
 350                 .name   = "cpufreq-dt",
 351         },
 352         .probe          = dt_cpufreq_probe,
 353         .remove_new     = dt_cpufreq_remove,
 354 };
 355 module_platform_driver(dt_cpufreq_platdrv);
 356
 357 MODULE_ALIAS("platform:cpufreq-dt");
 358 MODULE_AUTHOR("Viresh Kumar <[email protected]>");
 359 MODULE_AUTHOR("Shawn Guo <[email protected]>");
 360 MODULE_DESCRIPTION("Generic cpufreq driver");
 361 MODULE_LICENSE("GPL");