drivers/cpufreq/exynos-cpufreq.c

   1 /*
   2  * Copyright (c) 2010-2011 Samsung Electronics Co., Ltd.
   3  *              http://www.samsung.com
   4  *
   5  * EXYNOS - CPU frequency scaling support for EXYNOS series
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10 */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/err.h>
  14 #include <linux/clk.h>
  15 #include <linux/io.h>
  16 #include <linux/slab.h>
  17 #include <linux/regulator/consumer.h>
  18 #include <linux/cpufreq.h>
  19 #include <linux/suspend.h>
  20
  21 #include <plat/cpu.h>
  22
  23 #include "exynos-cpufreq.h"
  24
  25 static struct exynos_dvfs_info *exynos_info;
  26
  27 static struct regulator *arm_regulator;
  28 static struct cpufreq_freqs freqs;
  29
  30 static unsigned int locking_frequency;
  31 static bool frequency_locked;
  32 static DEFINE_MUTEX(cpufreq_lock);
  33
  34 static int exynos_verify_speed(struct cpufreq_policy *policy)
  35 {
  36         return cpufreq_frequency_table_verify(policy,
  37                                               exynos_info->freq_table);
  38 }
  39
  40 static unsigned int exynos_getspeed(unsigned int cpu)
  41 {
  42         return clk_get_rate(exynos_info->cpu_clk) / 1000;
  43 }
  44
  45 static int exynos_cpufreq_get_index(unsigned int freq)
  46 {
  47         struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
  48         int index;
  49
  50         for (index = 0;
  51                 freq_table[index].frequency != CPUFREQ_TABLE_END; index++)
  52                 if (freq_table[index].frequency == freq)
  53                         break;
  54
  55         if (freq_table[index].frequency == CPUFREQ_TABLE_END)
  56                 return -EINVAL;
  57
  58         return index;
  59 }
  60
  61 static int exynos_cpufreq_scale(unsigned int target_freq)
  62 {
  63         struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
  64         unsigned int *volt_table = exynos_info->volt_table;
  65         struct cpufreq_policy *policy = cpufreq_cpu_get(0);
  66         unsigned int arm_volt, safe_arm_volt = 0;
  67         unsigned int mpll_freq_khz = exynos_info->mpll_freq_khz;
  68         int index, old_index;
  69         int ret = 0;
  70
  71         freqs.old = policy->cur;
  72         freqs.new = target_freq;
  73
  74         if (freqs.new == freqs.old)
  75                 goto out;
  76
  77         /*
  78          * The policy max have been changed so that we cannot get proper
  79          * old_index with cpufreq_frequency_table_target(). Thus, ignore
  80          * policy and get the index from the raw freqeuncy table.
  81          */
  82         old_index = exynos_cpufreq_get_index(freqs.old);
  83         if (old_index < 0) {
  84                 ret = old_index;
  85                 goto out;
  86         }
  87
  88         index = exynos_cpufreq_get_index(target_freq);
  89         if (index < 0) {
  90                 ret = index;
  91                 goto out;
  92         }
  93
  94         /*
  95          * ARM clock source will be changed APLL to MPLL temporary
  96          * To support this level, need to control regulator for
  97          * required voltage level
  98          */
  99         if (exynos_info->need_apll_change != NULL) {
 100                 if (exynos_info->need_apll_change(old_index, index) &&
 101                    (freq_table[index].frequency < mpll_freq_khz) &&
 102                    (freq_table[old_index].frequency < mpll_freq_khz))
 103                         safe_arm_volt = volt_table[exynos_info->pll_safe_idx];
 104         }
 105         arm_volt = volt_table[index];
 106
 107         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
 108
 109         /* When the new frequency is higher than current frequency */
 110         if ((freqs.new > freqs.old) && !safe_arm_volt) {
 111                 /* Firstly, voltage up to increase frequency */
 112                 ret = regulator_set_voltage(arm_regulator, arm_volt, arm_volt);
 113                 if (ret) {
 114                         pr_err("%s: failed to set cpu voltage to %d\n",
 115                                 __func__, arm_volt);
 116                         freqs.new = freqs.old;
 117                         goto post_notify;
 118                 }
 119         }
 120
 121         if (safe_arm_volt) {
 122                 ret = regulator_set_voltage(arm_regulator, safe_arm_volt,
 123                                       safe_arm_volt);
 124                 if (ret) {
 125                         pr_err("%s: failed to set cpu voltage to %d\n",
 126                                 __func__, safe_arm_volt);
 127                         freqs.new = freqs.old;
 128                         goto post_notify;
 129                 }
 130         }
 131
 132         exynos_info->set_freq(old_index, index);
 133
 134 post_notify:
 135         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 136
 137         if (ret)
 138                 goto out;
 139
 140         /* When the new frequency is lower than current frequency */
 141         if ((freqs.new < freqs.old) ||
 142            ((freqs.new > freqs.old) && safe_arm_volt)) {
 143                 /* down the voltage after frequency change */
 144                 regulator_set_voltage(arm_regulator, arm_volt,
 145                                 arm_volt);
 146                 if (ret) {
 147                         pr_err("%s: failed to set cpu voltage to %d\n",
 148                                 __func__, arm_volt);
 149                         goto out;
 150                 }
 151         }
 152
 153 out:
 154
 155         cpufreq_cpu_put(policy);
 156
 157         return ret;
 158 }
 159
 160 static int exynos_target(struct cpufreq_policy *policy,
 161                           unsigned int target_freq,
 162                           unsigned int relation)
 163 {
 164         struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
 165         unsigned int index;
 166         unsigned int new_freq;
 167         int ret = 0;
 168
 169         mutex_lock(&cpufreq_lock);
 170
 171         if (frequency_locked)
 172                 goto out;
 173
 174         if (cpufreq_frequency_table_target(policy, freq_table,
 175                                            target_freq, relation, &index)) {
 176                 ret = -EINVAL;
 177                 goto out;
 178         }
 179
 180         new_freq = freq_table[index].frequency;
 181
 182         ret = exynos_cpufreq_scale(new_freq);
 183
 184 out:
 185         mutex_unlock(&cpufreq_lock);
 186
 187         return ret;
 188 }
 189
 190 #ifdef CONFIG_PM
 191 static int exynos_cpufreq_suspend(struct cpufreq_policy *policy)
 192 {
 193         return 0;
 194 }
 195
 196 static int exynos_cpufreq_resume(struct cpufreq_policy *policy)
 197 {
 198         return 0;
 199 }
 200 #endif
 201
 202 /**
 203  * exynos_cpufreq_pm_notifier - block CPUFREQ's activities in suspend-resume
 204  *                      context
 205  * @notifier
 206  * @pm_event
 207  * @v
 208  *
 209  * While frequency_locked == true, target() ignores every frequency but
 210  * locking_frequency. The locking_frequency value is the initial frequency,
 211  * which is set by the bootloader. In order to eliminate possible
 212  * inconsistency in clock values, we save and restore frequencies during
 213  * suspend and resume and block CPUFREQ activities. Note that the standard
 214  * suspend/resume cannot be used as they are too deep (syscore_ops) for
 215  * regulator actions.
 216  */
 217 static int exynos_cpufreq_pm_notifier(struct notifier_block *notifier,
 218                                        unsigned long pm_event, void *v)
 219 {
 220         int ret;
 221
 222         switch (pm_event) {
 223         case PM_SUSPEND_PREPARE:
 224                 mutex_lock(&cpufreq_lock);
 225                 frequency_locked = true;
 226                 mutex_unlock(&cpufreq_lock);
 227
 228                 ret = exynos_cpufreq_scale(locking_frequency);
 229                 if (ret < 0)
 230                         return NOTIFY_BAD;
 231
 232                 break;
 233
 234         case PM_POST_SUSPEND:
 235                 mutex_lock(&cpufreq_lock);
 236                 frequency_locked = false;
 237                 mutex_unlock(&cpufreq_lock);
 238                 break;
 239         }
 240
 241         return NOTIFY_OK;
 242 }
 243
 244 static struct notifier_block exynos_cpufreq_nb = {
 245         .notifier_call = exynos_cpufreq_pm_notifier,
 246 };
 247
 248 static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
 249 {
 250         policy->cur = policy->min = policy->max = exynos_getspeed(policy->cpu);
 251
 252         cpufreq_frequency_table_get_attr(exynos_info->freq_table, policy->cpu);
 253
 254         /* set the transition latency value */
 255         policy->cpuinfo.transition_latency = 100000;
 256
 257         cpumask_setall(policy->cpus);
 258
 259         return cpufreq_frequency_table_cpuinfo(policy, exynos_info->freq_table);
 260 }
 261
 262 static int exynos_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 263 {
 264         cpufreq_frequency_table_put_attr(policy->cpu);
 265         return 0;
 266 }
 267
 268 static struct freq_attr *exynos_cpufreq_attr[] = {
 269         &cpufreq_freq_attr_scaling_available_freqs,
 270         NULL,
 271 };
 272
 273 static struct cpufreq_driver exynos_driver = {
 274         .flags          = CPUFREQ_STICKY,
 275         .verify         = exynos_verify_speed,
 276         .target         = exynos_target,
 277         .get            = exynos_getspeed,
 278         .init           = exynos_cpufreq_cpu_init,
 279         .exit           = exynos_cpufreq_cpu_exit,
 280         .name           = "exynos_cpufreq",
 281         .attr           = exynos_cpufreq_attr,
 282 #ifdef CONFIG_PM
 283         .suspend        = exynos_cpufreq_suspend,
 284         .resume         = exynos_cpufreq_resume,
 285 #endif
 286 };
 287
 288 static int __init exynos_cpufreq_init(void)
 289 {
 290         int ret = -EINVAL;
 291
 292         exynos_info = kzalloc(sizeof(*exynos_info), GFP_KERNEL);
 293         if (!exynos_info)
 294                 return -ENOMEM;
 295
 296         if (soc_is_exynos4210())
 297                 ret = exynos4210_cpufreq_init(exynos_info);
 298         else if (soc_is_exynos4212() || soc_is_exynos4412())
 299                 ret = exynos4x12_cpufreq_init(exynos_info);
 300         else if (soc_is_exynos5250())
 301                 ret = exynos5250_cpufreq_init(exynos_info);
 302         else
 303                 return 0;
 304
 305         if (ret)
 306                 goto err_vdd_arm;
 307
 308         if (exynos_info->set_freq == NULL) {
 309                 pr_err("%s: No set_freq function (ERR)\n", __func__);
 310                 goto err_vdd_arm;
 311         }
 312
 313         arm_regulator = regulator_get(NULL, "vdd_arm");
 314         if (IS_ERR(arm_regulator)) {
 315                 pr_err("%s: failed to get resource vdd_arm\n", __func__);
 316                 goto err_vdd_arm;
 317         }
 318
 319         locking_frequency = exynos_getspeed(0);
 320
 321         register_pm_notifier(&exynos_cpufreq_nb);
 322
 323         if (cpufreq_register_driver(&exynos_driver)) {
 324                 pr_err("%s: failed to register cpufreq driver\n", __func__);
 325                 goto err_cpufreq;
 326         }
 327
 328         return 0;
 329 err_cpufreq:
 330         unregister_pm_notifier(&exynos_cpufreq_nb);
 331
 332         regulator_put(arm_regulator);
 333 err_vdd_arm:
 334         kfree(exynos_info);
 335         return -EINVAL;
 336 }
 337 late_initcall(exynos_cpufreq_init);