drivers/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/slab.h>
  22
  23 #include "opp.h"
  24
  25 #ifdef CONFIG_CPU_FREQ
  26
  27 /**
  28  * dev_pm_opp_init_cpufreq_table() - create a cpufreq table for a device
  29  * @dev:        device for which we do this operation
  30  * @table:      Cpufreq table returned back to caller
  31  *
  32  * Generate a cpufreq table for a provided device- this assumes that the
  33  * opp table is already initialized and ready for usage.
  34  *
  35  * This function allocates required memory for the cpufreq table. It is
  36  * expected that the caller does the required maintenance such as freeing
  37  * the table as required.
  38  *
  39  * Returns -EINVAL for bad pointers, -ENODEV if the device is not found, -ENOMEM
  40  * if no memory available for the operation (table is not populated), returns 0
  41  * if successful and table is populated.
  42  *
  43  * WARNING: It is  important for the callers to ensure refreshing their copy of
  44  * the table if any of the mentioned functions have been invoked in the interim.
  45  */
  46 int dev_pm_opp_init_cpufreq_table(struct device *dev,
  47                                   struct cpufreq_frequency_table **table)
  48 {
  49         struct dev_pm_opp *opp;
  50         struct cpufreq_frequency_table *freq_table = NULL;
  51         int i, max_opps, ret = 0;
  52         unsigned long rate;
  53
  54         max_opps = dev_pm_opp_get_opp_count(dev);
  55         if (max_opps <= 0)
  56                 return max_opps ? max_opps : -ENODATA;
  57
  58         freq_table = kcalloc((max_opps + 1), sizeof(*freq_table), GFP_KERNEL);
  59         if (!freq_table)
  60                 return -ENOMEM;
  61
  62         for (i = 0, rate = 0; i < max_opps; i++, rate++) {
  63                 /* find next rate */
  64                 opp = dev_pm_opp_find_freq_ceil(dev, &rate);
  65                 if (IS_ERR(opp)) {
  66                         ret = PTR_ERR(opp);
  67                         goto out;
  68                 }
  69                 freq_table[i].driver_data = i;
  70                 freq_table[i].frequency = rate / 1000;
  71
  72                 /* Is Boost/turbo opp ? */
  73                 if (dev_pm_opp_is_turbo(opp))
  74                         freq_table[i].flags = CPUFREQ_BOOST_FREQ;
  75
  76                 dev_pm_opp_put(opp);
  77         }
  78
  79         freq_table[i].driver_data = i;
  80         freq_table[i].frequency = CPUFREQ_TABLE_END;
  81
  82         *table = &freq_table[0];
  83
  84 out:
  85         if (ret)
  86                 kfree(freq_table);
  87
  88         return ret;
  89 }
  90 EXPORT_SYMBOL_GPL(dev_pm_opp_init_cpufreq_table);
  91
  92 /**
  93  * dev_pm_opp_free_cpufreq_table() - free the cpufreq table
  94  * @dev:        device for which we do this operation
  95  * @table:      table to free
  96  *
  97  * Free up the table allocated by dev_pm_opp_init_cpufreq_table
  98  */
  99 void dev_pm_opp_free_cpufreq_table(struct device *dev,
 100                                    struct cpufreq_frequency_table **table)
 101 {
 102         if (!table)
 103                 return;
 104
 105         kfree(*table);
 106         *table = NULL;
 107 }
 108 EXPORT_SYMBOL_GPL(dev_pm_opp_free_cpufreq_table);
 109 #endif  /* CONFIG_CPU_FREQ */
 110
 111 void _dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask,
 112                                       int last_cpu)
 113 {
 114         struct device *cpu_dev;
 115         int cpu;
 116
 117         WARN_ON(cpumask_empty(cpumask));
 118
 119         for_each_cpu(cpu, cpumask) {
 120                 if (cpu == last_cpu)
 121                         break;
 122
 123                 cpu_dev = get_cpu_device(cpu);
 124                 if (!cpu_dev) {
 125                         pr_err("%s: failed to get cpu%d device\n", __func__,
 126                                cpu);
 127                         continue;
 128                 }
 129
 130                 _dev_pm_opp_find_and_remove_table(cpu_dev);
 131         }
 132 }
 133
 134 /**
 135  * dev_pm_opp_cpumask_remove_table() - Removes OPP table for @cpumask
 136  * @cpumask:    cpumask for which OPP table needs to be removed
 137  *
 138  * This removes the OPP tables for CPUs present in the @cpumask.
 139  * This should be used to remove all the OPPs entries associated with
 140  * the cpus in @cpumask.
 141  */
 142 void dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask)
 143 {
 144         _dev_pm_opp_cpumask_remove_table(cpumask, -1);
 145 }
 146 EXPORT_SYMBOL_GPL(dev_pm_opp_cpumask_remove_table);
 147
 148 /**
 149  * dev_pm_opp_set_sharing_cpus() - Mark OPP table as shared by few CPUs
 150  * @cpu_dev:    CPU device for which we do this operation
 151  * @cpumask:    cpumask of the CPUs which share the OPP table with @cpu_dev
 152  *
 153  * This marks OPP table of the @cpu_dev as shared by the CPUs present in
 154  * @cpumask.
 155  *
 156  * Returns -ENODEV if OPP table isn't already present.
 157  */
 158 int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev,
 159                                 const struct cpumask *cpumask)
 160 {
 161         struct opp_device *opp_dev;
 162         struct opp_table *opp_table;
 163         struct device *dev;
 164         int cpu, ret = 0;
 165
 166         opp_table = _find_opp_table(cpu_dev);
 167         if (IS_ERR(opp_table))
 168                 return PTR_ERR(opp_table);
 169
 170         for_each_cpu(cpu, cpumask) {
 171                 if (cpu == cpu_dev->id)
 172                         continue;
 173
 174                 dev = get_cpu_device(cpu);
 175                 if (!dev) {
 176                         dev_err(cpu_dev, "%s: failed to get cpu%d device\n",
 177                                 __func__, cpu);
 178                         continue;
 179                 }
 180
 181                 opp_dev = _add_opp_dev(dev, opp_table);
 182                 if (!opp_dev) {
 183                         dev_err(dev, "%s: failed to add opp-dev for cpu%d device\n",
 184                                 __func__, cpu);
 185                         continue;
 186                 }
 187
 188                 /* Mark opp-table as multiple CPUs are sharing it now */
 189                 opp_table->shared_opp = OPP_TABLE_ACCESS_SHARED;
 190         }
 191
 192         dev_pm_opp_put_opp_table(opp_table);
 193
 194         return ret;
 195 }
 196 EXPORT_SYMBOL_GPL(dev_pm_opp_set_sharing_cpus);
 197
 198 /**
 199  * dev_pm_opp_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with @cpu_dev
 200  * @cpu_dev:    CPU device for which we do this operation
 201  * @cpumask:    cpumask to update with information of sharing CPUs
 202  *
 203  * This updates the @cpumask with CPUs that are sharing OPPs with @cpu_dev.
 204  *
 205  * Returns -ENODEV if OPP table isn't already present and -EINVAL if the OPP
 206  * table's status is access-unknown.
 207  */
 208 int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
 209 {
 210         struct opp_device *opp_dev;
 211         struct opp_table *opp_table;
 212         int ret = 0;
 213
 214         opp_table = _find_opp_table(cpu_dev);
 215         if (IS_ERR(opp_table))
 216                 return PTR_ERR(opp_table);
 217
 218         if (opp_table->shared_opp == OPP_TABLE_ACCESS_UNKNOWN) {
 219                 ret = -EINVAL;
 220                 goto put_opp_table;
 221         }
 222
 223         cpumask_clear(cpumask);
 224
 225         if (opp_table->shared_opp == OPP_TABLE_ACCESS_SHARED) {
 226                 mutex_lock(&opp_table->lock);
 227                 list_for_each_entry(opp_dev, &opp_table->dev_list, node)
 228                         cpumask_set_cpu(opp_dev->dev->id, cpumask);
 229                 mutex_unlock(&opp_table->lock);
 230         } else {
 231                 cpumask_set_cpu(cpu_dev->id, cpumask);
 232         }
 233
 234 put_opp_table:
 235         dev_pm_opp_put_opp_table(opp_table);
 236
 237         return ret;
 238 }
 239 EXPORT_SYMBOL_GPL(dev_pm_opp_get_sharing_cpus);