drivers/base/power/opp/cpu.c

   1 /*
   2  * Generic OPP helper interface for CPU device
   3  *
   4  * Copyright (C) 2009-2014 Texas Instruments Incorporated.
   5  *      Nishanth Menon
   6  *      Romit Dasgupta
   7  *      Kevin Hilman
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  15
  16 #include <linux/cpu.h>
  17 #include <linux/cpufreq.h>
  18 #include <linux/err.h>
  19 #include <linux/errno.h>
  20 #include <linux/export.h>
  21 #include <linux/of.h>
  22 #include <linux/slab.h>
  23
  24 #include "opp.h"
  25
  26 #ifdef CONFIG_CPU_FREQ
  27
  28 /**
  29  * dev_pm_opp_init_cpufreq_table() - create a cpufreq table for a device
  30  * @dev:        device for which we do this operation
  31  * @table:      Cpufreq table returned back to caller
  32  *
  33  * Generate a cpufreq table for a provided device- this assumes that the
  34  * opp list is already initialized and ready for usage.
  35  *
  36  * This function allocates required memory for the cpufreq table. It is
  37  * expected that the caller does the required maintenance such as freeing
  38  * the table as required.
  39  *
  40  * Returns -EINVAL for bad pointers, -ENODEV if the device is not found, -ENOMEM
  41  * if no memory available for the operation (table is not populated), returns 0
  42  * if successful and table is populated.
  43  *
  44  * WARNING: It is  important for the callers to ensure refreshing their copy of
  45  * the table if any of the mentioned functions have been invoked in the interim.
  46  *
  47  * Locking: The internal device_opp and opp structures are RCU protected.
  48  * Since we just use the regular accessor functions to access the internal data
  49  * structures, we use RCU read lock inside this function. As a result, users of
  50  * this function DONOT need to use explicit locks for invoking.
  51  */
  52 int dev_pm_opp_init_cpufreq_table(struct device *dev,
  53                                   struct cpufreq_frequency_table **table)
  54 {
  55         struct dev_pm_opp *opp;
  56         struct cpufreq_frequency_table *freq_table = NULL;
  57         int i, max_opps, ret = 0;
  58         unsigned long rate;
  59
  60         rcu_read_lock();
  61
  62         max_opps = dev_pm_opp_get_opp_count(dev);
  63         if (max_opps <= 0) {
  64                 ret = max_opps ? max_opps : -ENODATA;
  65                 goto out;
  66         }
  67
  68         freq_table = kcalloc((max_opps + 1), sizeof(*freq_table), GFP_ATOMIC);
  69         if (!freq_table) {
  70                 ret = -ENOMEM;
  71                 goto out;
  72         }
  73
  74         for (i = 0, rate = 0; i < max_opps; i++, rate++) {
  75                 /* find next rate */
  76                 opp = dev_pm_opp_find_freq_ceil(dev, &rate);
  77                 if (IS_ERR(opp)) {
  78                         ret = PTR_ERR(opp);
  79                         goto out;
  80                 }
  81                 freq_table[i].driver_data = i;
  82                 freq_table[i].frequency = rate / 1000;
  83
  84                 /* Is Boost/turbo opp ? */
  85                 if (dev_pm_opp_is_turbo(opp))
  86                         freq_table[i].flags = CPUFREQ_BOOST_FREQ;
  87         }
  88
  89         freq_table[i].driver_data = i;
  90         freq_table[i].frequency = CPUFREQ_TABLE_END;
  91
  92         *table = &freq_table[0];
  93
  94 out:
  95         rcu_read_unlock();
  96         if (ret)
  97                 kfree(freq_table);
  98
  99         return ret;
 100 }
 101 EXPORT_SYMBOL_GPL(dev_pm_opp_init_cpufreq_table);
 102
 103 /**
 104  * dev_pm_opp_free_cpufreq_table() - free the cpufreq table
 105  * @dev:        device for which we do this operation
 106  * @table:      table to free
 107  *
 108  * Free up the table allocated by dev_pm_opp_init_cpufreq_table
 109  */
 110 void dev_pm_opp_free_cpufreq_table(struct device *dev,
 111                                    struct cpufreq_frequency_table **table)
 112 {
 113         if (!table)
 114                 return;
 115
 116         kfree(*table);
 117         *table = NULL;
 118 }
 119 EXPORT_SYMBOL_GPL(dev_pm_opp_free_cpufreq_table);
 120 #endif  /* CONFIG_CPU_FREQ */
 121
 122 /* Required only for V1 bindings, as v2 can manage it from DT itself */
 123 int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask)
 124 {
 125         struct device_list_opp *list_dev;
 126         struct device_opp *dev_opp;
 127         struct device *dev;
 128         int cpu, ret = 0;
 129
 130         mutex_lock(&dev_opp_list_lock);
 131
 132         dev_opp = _find_device_opp(cpu_dev);
 133         if (IS_ERR(dev_opp)) {
 134                 ret = -EINVAL;
 135                 goto unlock;
 136         }
 137
 138         for_each_cpu(cpu, cpumask) {
 139                 if (cpu == cpu_dev->id)
 140                         continue;
 141
 142                 dev = get_cpu_device(cpu);
 143                 if (!dev) {
 144                         dev_err(cpu_dev, "%s: failed to get cpu%d device\n",
 145                                 __func__, cpu);
 146                         continue;
 147                 }
 148
 149                 list_dev = _add_list_dev(dev, dev_opp);
 150                 if (!list_dev) {
 151                         dev_err(dev, "%s: failed to add list-dev for cpu%d device\n",
 152                                 __func__, cpu);
 153                         continue;
 154                 }
 155         }
 156 unlock:
 157         mutex_unlock(&dev_opp_list_lock);
 158
 159         return ret;
 160 }
 161 EXPORT_SYMBOL_GPL(dev_pm_opp_set_sharing_cpus);
 162
 163 #ifdef CONFIG_OF
 164 void dev_pm_opp_of_cpumask_remove_table(cpumask_var_t cpumask)
 165 {
 166         struct device *cpu_dev;
 167         int cpu;
 168
 169         WARN_ON(cpumask_empty(cpumask));
 170
 171         for_each_cpu(cpu, cpumask) {
 172                 cpu_dev = get_cpu_device(cpu);
 173                 if (!cpu_dev) {
 174                         pr_err("%s: failed to get cpu%d device\n", __func__,
 175                                cpu);
 176                         continue;
 177                 }
 178
 179                 dev_pm_opp_of_remove_table(cpu_dev);
 180         }
 181 }
 182 EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_remove_table);
 183
 184 int dev_pm_opp_of_cpumask_add_table(cpumask_var_t cpumask)
 185 {
 186         struct device *cpu_dev;
 187         int cpu, ret = 0;
 188
 189         WARN_ON(cpumask_empty(cpumask));
 190
 191         for_each_cpu(cpu, cpumask) {
 192                 cpu_dev = get_cpu_device(cpu);
 193                 if (!cpu_dev) {
 194                         pr_err("%s: failed to get cpu%d device\n", __func__,
 195                                cpu);
 196                         continue;
 197                 }
 198
 199                 ret = dev_pm_opp_of_add_table(cpu_dev);
 200                 if (ret) {
 201                         pr_err("%s: couldn't find opp table for cpu:%d, %d\n",
 202                                __func__, cpu, ret);
 203
 204                         /* Free all other OPPs */
 205                         dev_pm_opp_of_cpumask_remove_table(cpumask);
 206                         break;
 207                 }
 208         }
 209
 210         return ret;
 211 }
 212 EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_add_table);
 213
 214 /*
 215  * Works only for OPP v2 bindings.
 216  *
 217  * Returns -ENOENT if operating-points-v2 bindings aren't supported.
 218  */
 219 int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask)
 220 {
 221         struct device_node *np, *tmp_np;
 222         struct device *tcpu_dev;
 223         int cpu, ret = 0;
 224
 225         /* Get OPP descriptor node */
 226         np = _of_get_opp_desc_node(cpu_dev);
 227         if (!np) {
 228                 dev_dbg(cpu_dev, "%s: Couldn't find cpu_dev node.\n", __func__);
 229                 return -ENOENT;
 230         }
 231
 232         cpumask_set_cpu(cpu_dev->id, cpumask);
 233
 234         /* OPPs are shared ? */
 235         if (!of_property_read_bool(np, "opp-shared"))
 236                 goto put_cpu_node;
 237
 238         for_each_possible_cpu(cpu) {
 239                 if (cpu == cpu_dev->id)
 240                         continue;
 241
 242                 tcpu_dev = get_cpu_device(cpu);
 243                 if (!tcpu_dev) {
 244                         dev_err(cpu_dev, "%s: failed to get cpu%d device\n",
 245                                 __func__, cpu);
 246                         ret = -ENODEV;
 247                         goto put_cpu_node;
 248                 }
 249
 250                 /* Get OPP descriptor node */
 251                 tmp_np = _of_get_opp_desc_node(tcpu_dev);
 252                 if (!tmp_np) {
 253                         dev_err(tcpu_dev, "%s: Couldn't find tcpu_dev node.\n",
 254                                 __func__);
 255                         ret = -ENOENT;
 256                         goto put_cpu_node;
 257                 }
 258
 259                 /* CPUs are sharing opp node */
 260                 if (np == tmp_np)
 261                         cpumask_set_cpu(cpu, cpumask);
 262
 263                 of_node_put(tmp_np);
 264         }
 265
 266 put_cpu_node:
 267         of_node_put(np);
 268         return ret;
 269 }
 270 EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_sharing_cpus);
 271 #endif