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