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         freqs.cpu = policy->cpu;
  74
  75         if (freqs.new == freqs.old)
  76                 goto out;
  77
  78         /*
  79          * The policy max have been changed so that we cannot get proper
  80          * old_index with cpufreq_frequency_table_target(). Thus, ignore
  81          * policy and get the index from the raw freqeuncy table.
  82          */
  83         old_index = exynos_cpufreq_get_index(freqs.old);
  84         if (old_index < 0) {
  85                 ret = old_index;
  86                 goto out;
  87         }
  88
  89         index = exynos_cpufreq_get_index(target_freq);
  90         if (index < 0) {
  91                 ret = index;
  92                 goto out;
  93         }
  94
  95         /*
  96          * ARM clock source will be changed APLL to MPLL temporary
  97          * To support this level, need to control regulator for
  98          * required voltage level
  99          */
 100         if (exynos_info->need_apll_change != NULL) {
 101                 if (exynos_info->need_apll_change(old_index, index) &&
 102                    (freq_table[index].frequency < mpll_freq_khz) &&
 103                    (freq_table[old_index].frequency < mpll_freq_khz))
 104                         safe_arm_volt = volt_table[exynos_info->pll_safe_idx];
 105         }
 106         arm_volt = volt_table[index];
 107
 108         for_each_cpu(freqs.cpu, policy->cpus)
 109                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 110
 111         /* When the new frequency is higher than current frequency */
 112         if ((freqs.new > freqs.old) && !safe_arm_volt) {
 113                 /* Firstly, voltage up to increase frequency */
 114                 ret = regulator_set_voltage(arm_regulator, arm_volt, arm_volt);
 115                 if (ret) {
 116                         pr_err("%s: failed to set cpu voltage to %d\n",
 117                                 __func__, arm_volt);
 118                         goto out;
 119                 }
 120         }
 121
 122         if (safe_arm_volt) {
 123                 ret = regulator_set_voltage(arm_regulator, safe_arm_volt,
 124                                       safe_arm_volt);
 125                 if (ret) {
 126                         pr_err("%s: failed to set cpu voltage to %d\n",
 127                                 __func__, safe_arm_volt);
 128                         goto out;
 129                 }
 130         }
 131
 132         exynos_info->set_freq(old_index, index);
 133
 134         for_each_cpu(freqs.cpu, policy->cpus)
 135                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 136
 137         /* When the new frequency is lower than current frequency */
 138         if ((freqs.new < freqs.old) ||
 139            ((freqs.new > freqs.old) && safe_arm_volt)) {
 140                 /* down the voltage after frequency change */
 141                 regulator_set_voltage(arm_regulator, arm_volt,
 142                                 arm_volt);
 143                 if (ret) {
 144                         pr_err("%s: failed to set cpu voltage to %d\n",
 145                                 __func__, arm_volt);
 146                         goto out;
 147                 }
 148         }
 149
 150 out:
 151
 152         cpufreq_cpu_put(policy);
 153
 154         return ret;
 155 }
 156
 157 static int exynos_target(struct cpufreq_policy *policy,
 158                           unsigned int target_freq,
 159                           unsigned int relation)
 160 {
 161         struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
 162         unsigned int index;
 163         unsigned int new_freq;
 164         int ret = 0;
 165
 166         mutex_lock(&cpufreq_lock);
 167
 168         if (frequency_locked)
 169                 goto out;
 170
 171         if (cpufreq_frequency_table_target(policy, freq_table,
 172                                            target_freq, relation, &index)) {
 173                 ret = -EINVAL;
 174                 goto out;
 175         }
 176
 177         new_freq = freq_table[index].frequency;
 178
 179         ret = exynos_cpufreq_scale(new_freq);
 180
 181 out:
 182         mutex_unlock(&cpufreq_lock);
 183
 184         return ret;
 185 }
 186
 187 #ifdef CONFIG_PM
 188 static int exynos_cpufreq_suspend(struct cpufreq_policy *policy)
 189 {
 190         return 0;
 191 }
 192
 193 static int exynos_cpufreq_resume(struct cpufreq_policy *policy)
 194 {
 195         return 0;
 196 }
 197 #endif
 198
 199 /**
 200  * exynos_cpufreq_pm_notifier - block CPUFREQ's activities in suspend-resume
 201  *                      context
 202  * @notifier
 203  * @pm_event
 204  * @v
 205  *
 206  * While frequency_locked == true, target() ignores every frequency but
 207  * locking_frequency. The locking_frequency value is the initial frequency,
 208  * which is set by the bootloader. In order to eliminate possible
 209  * inconsistency in clock values, we save and restore frequencies during
 210  * suspend and resume and block CPUFREQ activities. Note that the standard
 211  * suspend/resume cannot be used as they are too deep (syscore_ops) for
 212  * regulator actions.
 213  */
 214 static int exynos_cpufreq_pm_notifier(struct notifier_block *notifier,
 215                                        unsigned long pm_event, void *v)
 216 {
 217         int ret;
 218
 219         switch (pm_event) {
 220         case PM_SUSPEND_PREPARE:
 221                 mutex_lock(&cpufreq_lock);
 222                 frequency_locked = true;
 223                 mutex_unlock(&cpufreq_lock);
 224
 225                 ret = exynos_cpufreq_scale(locking_frequency);
 226                 if (ret < 0)
 227                         return NOTIFY_BAD;
 228
 229                 break;
 230
 231         case PM_POST_SUSPEND:
 232                 mutex_lock(&cpufreq_lock);
 233                 frequency_locked = false;
 234                 mutex_unlock(&cpufreq_lock);
 235                 break;
 236         }
 237
 238         return NOTIFY_OK;
 239 }
 240
 241 static struct notifier_block exynos_cpufreq_nb = {
 242         .notifier_call = exynos_cpufreq_pm_notifier,
 243 };
 244
 245 static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
 246 {
 247         policy->cur = policy->min = policy->max = exynos_getspeed(policy->cpu);
 248
 249         cpufreq_frequency_table_get_attr(exynos_info->freq_table, policy->cpu);
 250
 251         /* set the transition latency value */
 252         policy->cpuinfo.transition_latency = 100000;
 253
 254         cpumask_setall(policy->cpus);
 255
 256         return cpufreq_frequency_table_cpuinfo(policy, exynos_info->freq_table);
 257 }
 258
 259 static int exynos_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 260 {
 261         cpufreq_frequency_table_put_attr(policy->cpu);
 262         return 0;
 263 }
 264
 265 static struct freq_attr *exynos_cpufreq_attr[] = {
 266         &cpufreq_freq_attr_scaling_available_freqs,
 267         NULL,
 268 };
 269
 270 static struct cpufreq_driver exynos_driver = {
 271         .flags          = CPUFREQ_STICKY,
 272         .verify         = exynos_verify_speed,
 273         .target         = exynos_target,
 274         .get            = exynos_getspeed,
 275         .init           = exynos_cpufreq_cpu_init,
 276         .exit           = exynos_cpufreq_cpu_exit,
 277         .name           = "exynos_cpufreq",
 278         .attr           = exynos_cpufreq_attr,
 279 #ifdef CONFIG_PM
 280         .suspend        = exynos_cpufreq_suspend,
 281         .resume         = exynos_cpufreq_resume,
 282 #endif
 283 };
 284
 285 static int __init exynos_cpufreq_init(void)
 286 {
 287         int ret = -EINVAL;
 288
 289         exynos_info = kzalloc(sizeof(struct exynos_dvfs_info), GFP_KERNEL);
 290         if (!exynos_info)
 291                 return -ENOMEM;
 292
 293         if (soc_is_exynos4210())
 294                 ret = exynos4210_cpufreq_init(exynos_info);
 295         else if (soc_is_exynos4212() || soc_is_exynos4412())
 296                 ret = exynos4x12_cpufreq_init(exynos_info);
 297         else if (soc_is_exynos5250())
 298                 ret = exynos5250_cpufreq_init(exynos_info);
 299         else
 300                 pr_err("%s: CPU type not found\n", __func__);
 301
 302         if (ret)
 303                 goto err_vdd_arm;
 304
 305         if (exynos_info->set_freq == NULL) {
 306                 pr_err("%s: No set_freq function (ERR)\n", __func__);
 307                 goto err_vdd_arm;
 308         }
 309
 310         arm_regulator = regulator_get(NULL, "vdd_arm");
 311         if (IS_ERR(arm_regulator)) {
 312                 pr_err("%s: failed to get resource vdd_arm\n", __func__);
 313                 goto err_vdd_arm;
 314         }
 315
 316         locking_frequency = exynos_getspeed(0);
 317
 318         register_pm_notifier(&exynos_cpufreq_nb);
 319
 320         if (cpufreq_register_driver(&exynos_driver)) {
 321                 pr_err("%s: failed to register cpufreq driver\n", __func__);
 322                 goto err_cpufreq;
 323         }
 324
 325         return 0;
 326 err_cpufreq:
 327         unregister_pm_notifier(&exynos_cpufreq_nb);
 328
 329         regulator_put(arm_regulator);
 330 err_vdd_arm:
 331         kfree(exynos_info);
 332         pr_debug("%s: failed initialization\n", __func__);
 333         return -EINVAL;
 334 }
 335 late_initcall(exynos_cpufreq_init);