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 unsigned int exynos_getspeed(unsigned int cpu)
  35 {
  36         return clk_get_rate(exynos_info->cpu_clk) / 1000;
  37 }
  38
  39 static int exynos_cpufreq_get_index(unsigned int freq)
  40 {
  41         struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
  42         int index;
  43
  44         for (index = 0;
  45                 freq_table[index].frequency != CPUFREQ_TABLE_END; index++)
  46                 if (freq_table[index].frequency == freq)
  47                         break;
  48
  49         if (freq_table[index].frequency == CPUFREQ_TABLE_END)
  50                 return -EINVAL;
  51
  52         return index;
  53 }
  54
  55 static int exynos_cpufreq_scale(unsigned int target_freq)
  56 {
  57         struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
  58         unsigned int *volt_table = exynos_info->volt_table;
  59         struct cpufreq_policy *policy = cpufreq_cpu_get(0);
  60         unsigned int arm_volt, safe_arm_volt = 0;
  61         unsigned int mpll_freq_khz = exynos_info->mpll_freq_khz;
  62         int index, old_index;
  63         int ret = 0;
  64
  65         freqs.old = policy->cur;
  66         freqs.new = target_freq;
  67
  68         /*
  69          * The policy max have been changed so that we cannot get proper
  70          * old_index with cpufreq_frequency_table_target(). Thus, ignore
  71          * policy and get the index from the raw freqeuncy table.
  72          */
  73         old_index = exynos_cpufreq_get_index(freqs.old);
  74         if (old_index < 0) {
  75                 ret = old_index;
  76                 goto out;
  77         }
  78
  79         index = exynos_cpufreq_get_index(target_freq);
  80         if (index < 0) {
  81                 ret = index;
  82                 goto out;
  83         }
  84
  85         /*
  86          * ARM clock source will be changed APLL to MPLL temporary
  87          * To support this level, need to control regulator for
  88          * required voltage level
  89          */
  90         if (exynos_info->need_apll_change != NULL) {
  91                 if (exynos_info->need_apll_change(old_index, index) &&
  92                    (freq_table[index].frequency < mpll_freq_khz) &&
  93                    (freq_table[old_index].frequency < mpll_freq_khz))
  94                         safe_arm_volt = volt_table[exynos_info->pll_safe_idx];
  95         }
  96         arm_volt = volt_table[index];
  97
  98         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
  99
 100         /* When the new frequency is higher than current frequency */
 101         if ((freqs.new > freqs.old) && !safe_arm_volt) {
 102                 /* Firstly, voltage up to increase frequency */
 103                 ret = regulator_set_voltage(arm_regulator, arm_volt, arm_volt);
 104                 if (ret) {
 105                         pr_err("%s: failed to set cpu voltage to %d\n",
 106                                 __func__, arm_volt);
 107                         freqs.new = freqs.old;
 108                         goto post_notify;
 109                 }
 110         }
 111
 112         if (safe_arm_volt) {
 113                 ret = regulator_set_voltage(arm_regulator, safe_arm_volt,
 114                                       safe_arm_volt);
 115                 if (ret) {
 116                         pr_err("%s: failed to set cpu voltage to %d\n",
 117                                 __func__, safe_arm_volt);
 118                         freqs.new = freqs.old;
 119                         goto post_notify;
 120                 }
 121         }
 122
 123         exynos_info->set_freq(old_index, index);
 124
 125 post_notify:
 126         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 127
 128         if (ret)
 129                 goto out;
 130
 131         /* When the new frequency is lower than current frequency */
 132         if ((freqs.new < freqs.old) ||
 133            ((freqs.new > freqs.old) && safe_arm_volt)) {
 134                 /* down the voltage after frequency change */
 135                 ret = regulator_set_voltage(arm_regulator, arm_volt,
 136                                 arm_volt);
 137                 if (ret) {
 138                         pr_err("%s: failed to set cpu voltage to %d\n",
 139                                 __func__, arm_volt);
 140                         goto out;
 141                 }
 142         }
 143
 144 out:
 145
 146         cpufreq_cpu_put(policy);
 147
 148         return ret;
 149 }
 150
 151 static int exynos_target(struct cpufreq_policy *policy, unsigned int index)
 152 {
 153         struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
 154         int ret = 0;
 155
 156         mutex_lock(&cpufreq_lock);
 157
 158         if (frequency_locked)
 159                 goto out;
 160
 161         ret = exynos_cpufreq_scale(freq_table[index].frequency);
 162
 163 out:
 164         mutex_unlock(&cpufreq_lock);
 165
 166         return ret;
 167 }
 168
 169 #ifdef CONFIG_PM
 170 static int exynos_cpufreq_suspend(struct cpufreq_policy *policy)
 171 {
 172         return 0;
 173 }
 174
 175 static int exynos_cpufreq_resume(struct cpufreq_policy *policy)
 176 {
 177         return 0;
 178 }
 179 #endif
 180
 181 /**
 182  * exynos_cpufreq_pm_notifier - block CPUFREQ's activities in suspend-resume
 183  *                      context
 184  * @notifier
 185  * @pm_event
 186  * @v
 187  *
 188  * While frequency_locked == true, target() ignores every frequency but
 189  * locking_frequency. The locking_frequency value is the initial frequency,
 190  * which is set by the bootloader. In order to eliminate possible
 191  * inconsistency in clock values, we save and restore frequencies during
 192  * suspend and resume and block CPUFREQ activities. Note that the standard
 193  * suspend/resume cannot be used as they are too deep (syscore_ops) for
 194  * regulator actions.
 195  */
 196 static int exynos_cpufreq_pm_notifier(struct notifier_block *notifier,
 197                                        unsigned long pm_event, void *v)
 198 {
 199         int ret;
 200
 201         switch (pm_event) {
 202         case PM_SUSPEND_PREPARE:
 203                 mutex_lock(&cpufreq_lock);
 204                 frequency_locked = true;
 205                 mutex_unlock(&cpufreq_lock);
 206
 207                 ret = exynos_cpufreq_scale(locking_frequency);
 208                 if (ret < 0)
 209                         return NOTIFY_BAD;
 210
 211                 break;
 212
 213         case PM_POST_SUSPEND:
 214                 mutex_lock(&cpufreq_lock);
 215                 frequency_locked = false;
 216                 mutex_unlock(&cpufreq_lock);
 217                 break;
 218         }
 219
 220         return NOTIFY_OK;
 221 }
 222
 223 static struct notifier_block exynos_cpufreq_nb = {
 224         .notifier_call = exynos_cpufreq_pm_notifier,
 225 };
 226
 227 static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
 228 {
 229         return cpufreq_generic_init(policy, exynos_info->freq_table, 100000);
 230 }
 231
 232 static struct cpufreq_driver exynos_driver = {
 233         .flags          = CPUFREQ_STICKY,
 234         .verify         = cpufreq_generic_frequency_table_verify,
 235         .target_index   = exynos_target,
 236         .get            = exynos_getspeed,
 237         .init           = exynos_cpufreq_cpu_init,
 238         .exit           = cpufreq_generic_exit,
 239         .name           = "exynos_cpufreq",
 240         .attr           = cpufreq_generic_attr,
 241 #ifdef CONFIG_PM
 242         .suspend        = exynos_cpufreq_suspend,
 243         .resume         = exynos_cpufreq_resume,
 244 #endif
 245 };
 246
 247 static int __init exynos_cpufreq_init(void)
 248 {
 249         int ret = -EINVAL;
 250
 251         exynos_info = kzalloc(sizeof(*exynos_info), GFP_KERNEL);
 252         if (!exynos_info)
 253                 return -ENOMEM;
 254
 255         if (soc_is_exynos4210())
 256                 ret = exynos4210_cpufreq_init(exynos_info);
 257         else if (soc_is_exynos4212() || soc_is_exynos4412())
 258                 ret = exynos4x12_cpufreq_init(exynos_info);
 259         else if (soc_is_exynos5250())
 260                 ret = exynos5250_cpufreq_init(exynos_info);
 261         else
 262                 return 0;
 263
 264         if (ret)
 265                 goto err_vdd_arm;
 266
 267         if (exynos_info->set_freq == NULL) {
 268                 pr_err("%s: No set_freq function (ERR)\n", __func__);
 269                 goto err_vdd_arm;
 270         }
 271
 272         arm_regulator = regulator_get(NULL, "vdd_arm");
 273         if (IS_ERR(arm_regulator)) {
 274                 pr_err("%s: failed to get resource vdd_arm\n", __func__);
 275                 goto err_vdd_arm;
 276         }
 277
 278         locking_frequency = exynos_getspeed(0);
 279
 280         register_pm_notifier(&exynos_cpufreq_nb);
 281
 282         if (cpufreq_register_driver(&exynos_driver)) {
 283                 pr_err("%s: failed to register cpufreq driver\n", __func__);
 284                 goto err_cpufreq;
 285         }
 286
 287         return 0;
 288 err_cpufreq:
 289         unregister_pm_notifier(&exynos_cpufreq_nb);
 290
 291         regulator_put(arm_regulator);
 292 err_vdd_arm:
 293         kfree(exynos_info);
 294         return -EINVAL;
 295 }
 296 late_initcall(exynos_cpufreq_init);