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 #include <linux/platform_device.h>
  21
  22 #include <plat/cpu.h>
  23
  24 #include "exynos-cpufreq.h"
  25
  26 static struct exynos_dvfs_info *exynos_info;
  27
  28 static struct regulator *arm_regulator;
  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         unsigned int old_freq;
  63         int index, old_index;
  64         int ret = 0;
  65
  66         old_freq = policy->cur;
  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 frequency table.
  72          */
  73         old_index = exynos_cpufreq_get_index(old_freq);
  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         /* When the new frequency is higher than current frequency */
  99         if ((target_freq > old_freq) && !safe_arm_volt) {
 100                 /* Firstly, voltage up to increase frequency */
 101                 ret = regulator_set_voltage(arm_regulator, arm_volt, arm_volt);
 102                 if (ret) {
 103                         pr_err("%s: failed to set cpu voltage to %d\n",
 104                                 __func__, arm_volt);
 105                         return ret;
 106                 }
 107         }
 108
 109         if (safe_arm_volt) {
 110                 ret = regulator_set_voltage(arm_regulator, safe_arm_volt,
 111                                       safe_arm_volt);
 112                 if (ret) {
 113                         pr_err("%s: failed to set cpu voltage to %d\n",
 114                                 __func__, safe_arm_volt);
 115                         return ret;
 116                 }
 117         }
 118
 119         exynos_info->set_freq(old_index, index);
 120
 121         /* When the new frequency is lower than current frequency */
 122         if ((target_freq < old_freq) ||
 123            ((target_freq > old_freq) && safe_arm_volt)) {
 124                 /* down the voltage after frequency change */
 125                 ret = regulator_set_voltage(arm_regulator, arm_volt,
 126                                 arm_volt);
 127                 if (ret) {
 128                         pr_err("%s: failed to set cpu voltage to %d\n",
 129                                 __func__, arm_volt);
 130                         goto out;
 131                 }
 132         }
 133
 134 out:
 135         cpufreq_cpu_put(policy);
 136
 137         return ret;
 138 }
 139
 140 static int exynos_target(struct cpufreq_policy *policy, unsigned int index)
 141 {
 142         struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
 143         int ret = 0;
 144
 145         mutex_lock(&cpufreq_lock);
 146
 147         if (frequency_locked)
 148                 goto out;
 149
 150         ret = exynos_cpufreq_scale(freq_table[index].frequency);
 151
 152 out:
 153         mutex_unlock(&cpufreq_lock);
 154
 155         return ret;
 156 }
 157
 158 #ifdef CONFIG_PM
 159 static int exynos_cpufreq_suspend(struct cpufreq_policy *policy)
 160 {
 161         return 0;
 162 }
 163
 164 static int exynos_cpufreq_resume(struct cpufreq_policy *policy)
 165 {
 166         return 0;
 167 }
 168 #endif
 169
 170 /**
 171  * exynos_cpufreq_pm_notifier - block CPUFREQ's activities in suspend-resume
 172  *                      context
 173  * @notifier
 174  * @pm_event
 175  * @v
 176  *
 177  * While frequency_locked == true, target() ignores every frequency but
 178  * locking_frequency. The locking_frequency value is the initial frequency,
 179  * which is set by the bootloader. In order to eliminate possible
 180  * inconsistency in clock values, we save and restore frequencies during
 181  * suspend and resume and block CPUFREQ activities. Note that the standard
 182  * suspend/resume cannot be used as they are too deep (syscore_ops) for
 183  * regulator actions.
 184  */
 185 static int exynos_cpufreq_pm_notifier(struct notifier_block *notifier,
 186                                        unsigned long pm_event, void *v)
 187 {
 188         int ret;
 189
 190         switch (pm_event) {
 191         case PM_SUSPEND_PREPARE:
 192                 mutex_lock(&cpufreq_lock);
 193                 frequency_locked = true;
 194                 mutex_unlock(&cpufreq_lock);
 195
 196                 ret = exynos_cpufreq_scale(locking_frequency);
 197                 if (ret < 0)
 198                         return NOTIFY_BAD;
 199
 200                 break;
 201
 202         case PM_POST_SUSPEND:
 203                 mutex_lock(&cpufreq_lock);
 204                 frequency_locked = false;
 205                 mutex_unlock(&cpufreq_lock);
 206                 break;
 207         }
 208
 209         return NOTIFY_OK;
 210 }
 211
 212 static struct notifier_block exynos_cpufreq_nb = {
 213         .notifier_call = exynos_cpufreq_pm_notifier,
 214 };
 215
 216 static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
 217 {
 218         return cpufreq_generic_init(policy, exynos_info->freq_table, 100000);
 219 }
 220
 221 static struct cpufreq_driver exynos_driver = {
 222         .flags          = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 223         .verify         = cpufreq_generic_frequency_table_verify,
 224         .target_index   = exynos_target,
 225         .get            = exynos_getspeed,
 226         .init           = exynos_cpufreq_cpu_init,
 227         .exit           = cpufreq_generic_exit,
 228         .name           = "exynos_cpufreq",
 229         .attr           = cpufreq_generic_attr,
 230 #ifdef CONFIG_PM
 231         .suspend        = exynos_cpufreq_suspend,
 232         .resume         = exynos_cpufreq_resume,
 233 #endif
 234 };
 235
 236 static int exynos_cpufreq_probe(struct platform_device *pdev)
 237 {
 238         int ret = -EINVAL;
 239
 240         exynos_info = kzalloc(sizeof(*exynos_info), GFP_KERNEL);
 241         if (!exynos_info)
 242                 return -ENOMEM;
 243
 244         if (soc_is_exynos4210())
 245                 ret = exynos4210_cpufreq_init(exynos_info);
 246         else if (soc_is_exynos4212() || soc_is_exynos4412())
 247                 ret = exynos4x12_cpufreq_init(exynos_info);
 248         else if (soc_is_exynos5250())
 249                 ret = exynos5250_cpufreq_init(exynos_info);
 250         else
 251                 return 0;
 252
 253         if (ret)
 254                 goto err_vdd_arm;
 255
 256         if (exynos_info->set_freq == NULL) {
 257                 pr_err("%s: No set_freq function (ERR)\n", __func__);
 258                 goto err_vdd_arm;
 259         }
 260
 261         arm_regulator = regulator_get(NULL, "vdd_arm");
 262         if (IS_ERR(arm_regulator)) {
 263                 pr_err("%s: failed to get resource vdd_arm\n", __func__);
 264                 goto err_vdd_arm;
 265         }
 266
 267         locking_frequency = exynos_getspeed(0);
 268
 269         register_pm_notifier(&exynos_cpufreq_nb);
 270
 271         if (cpufreq_register_driver(&exynos_driver)) {
 272                 pr_err("%s: failed to register cpufreq driver\n", __func__);
 273                 goto err_cpufreq;
 274         }
 275
 276         return 0;
 277 err_cpufreq:
 278         unregister_pm_notifier(&exynos_cpufreq_nb);
 279
 280         regulator_put(arm_regulator);
 281 err_vdd_arm:
 282         kfree(exynos_info);
 283         return -EINVAL;
 284 }
 285
 286 static struct platform_driver exynos_cpufreq_platdrv = {
 287         .driver = {
 288                 .name   = "exynos-cpufreq",
 289                 .owner  = THIS_MODULE,
 290         },
 291         .probe = exynos_cpufreq_probe,
 292 };
 293 module_platform_driver(exynos_cpufreq_platdrv);