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/platform_device.h>
  20
  21 #include <plat/cpu.h>
  22
  23 #include "exynos-cpufreq.h"
  24
  25 static struct exynos_dvfs_info *exynos_info;
  26 static struct regulator *arm_regulator;
  27 static unsigned int locking_frequency;
  28
  29 static int exynos_cpufreq_get_index(unsigned int freq)
  30 {
  31         struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
  32         int index;
  33
  34         for (index = 0;
  35                 freq_table[index].frequency != CPUFREQ_TABLE_END; index++)
  36                 if (freq_table[index].frequency == freq)
  37                         break;
  38
  39         if (freq_table[index].frequency == CPUFREQ_TABLE_END)
  40                 return -EINVAL;
  41
  42         return index;
  43 }
  44
  45 static int exynos_cpufreq_scale(unsigned int target_freq)
  46 {
  47         struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
  48         unsigned int *volt_table = exynos_info->volt_table;
  49         struct cpufreq_policy *policy = cpufreq_cpu_get(0);
  50         unsigned int arm_volt, safe_arm_volt = 0;
  51         unsigned int mpll_freq_khz = exynos_info->mpll_freq_khz;
  52         unsigned int old_freq;
  53         int index, old_index;
  54         int ret = 0;
  55
  56         old_freq = policy->cur;
  57
  58         /*
  59          * The policy max have been changed so that we cannot get proper
  60          * old_index with cpufreq_frequency_table_target(). Thus, ignore
  61          * policy and get the index from the raw frequency table.
  62          */
  63         old_index = exynos_cpufreq_get_index(old_freq);
  64         if (old_index < 0) {
  65                 ret = old_index;
  66                 goto out;
  67         }
  68
  69         index = exynos_cpufreq_get_index(target_freq);
  70         if (index < 0) {
  71                 ret = index;
  72                 goto out;
  73         }
  74
  75         /*
  76          * ARM clock source will be changed APLL to MPLL temporary
  77          * To support this level, need to control regulator for
  78          * required voltage level
  79          */
  80         if (exynos_info->need_apll_change != NULL) {
  81                 if (exynos_info->need_apll_change(old_index, index) &&
  82                    (freq_table[index].frequency < mpll_freq_khz) &&
  83                    (freq_table[old_index].frequency < mpll_freq_khz))
  84                         safe_arm_volt = volt_table[exynos_info->pll_safe_idx];
  85         }
  86         arm_volt = volt_table[index];
  87
  88         /* When the new frequency is higher than current frequency */
  89         if ((target_freq > old_freq) && !safe_arm_volt) {
  90                 /* Firstly, voltage up to increase frequency */
  91                 ret = regulator_set_voltage(arm_regulator, arm_volt, arm_volt);
  92                 if (ret) {
  93                         pr_err("%s: failed to set cpu voltage to %d\n",
  94                                 __func__, arm_volt);
  95                         return ret;
  96                 }
  97         }
  98
  99         if (safe_arm_volt) {
 100                 ret = regulator_set_voltage(arm_regulator, safe_arm_volt,
 101                                       safe_arm_volt);
 102                 if (ret) {
 103                         pr_err("%s: failed to set cpu voltage to %d\n",
 104                                 __func__, safe_arm_volt);
 105                         return ret;
 106                 }
 107         }
 108
 109         exynos_info->set_freq(old_index, index);
 110
 111         /* When the new frequency is lower than current frequency */
 112         if ((target_freq < old_freq) ||
 113            ((target_freq > old_freq) && safe_arm_volt)) {
 114                 /* down the voltage after frequency change */
 115                 ret = regulator_set_voltage(arm_regulator, arm_volt,
 116                                 arm_volt);
 117                 if (ret) {
 118                         pr_err("%s: failed to set cpu voltage to %d\n",
 119                                 __func__, arm_volt);
 120                         goto out;
 121                 }
 122         }
 123
 124 out:
 125         cpufreq_cpu_put(policy);
 126
 127         return ret;
 128 }
 129
 130 static int exynos_target(struct cpufreq_policy *policy, unsigned int index)
 131 {
 132         return exynos_cpufreq_scale(exynos_info->freq_table[index].frequency);
 133 }
 134
 135 static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
 136 {
 137         policy->clk = exynos_info->cpu_clk;
 138         policy->suspend_freq = locking_frequency;
 139         return cpufreq_generic_init(policy, exynos_info->freq_table, 100000);
 140 }
 141
 142 static struct cpufreq_driver exynos_driver = {
 143         .flags          = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 144         .verify         = cpufreq_generic_frequency_table_verify,
 145         .target_index   = exynos_target,
 146         .get            = cpufreq_generic_get,
 147         .init           = exynos_cpufreq_cpu_init,
 148         .name           = "exynos_cpufreq",
 149         .attr           = cpufreq_generic_attr,
 150 #ifdef CONFIG_ARM_EXYNOS_CPU_FREQ_BOOST_SW
 151         .boost_supported = true,
 152 #endif
 153 #ifdef CONFIG_PM
 154         .suspend        = cpufreq_generic_suspend,
 155 #endif
 156 };
 157
 158 static int exynos_cpufreq_probe(struct platform_device *pdev)
 159 {
 160         int ret = -EINVAL;
 161
 162         exynos_info = kzalloc(sizeof(*exynos_info), GFP_KERNEL);
 163         if (!exynos_info)
 164                 return -ENOMEM;
 165
 166         if (soc_is_exynos4210())
 167                 ret = exynos4210_cpufreq_init(exynos_info);
 168         else if (soc_is_exynos4212() || soc_is_exynos4412())
 169                 ret = exynos4x12_cpufreq_init(exynos_info);
 170         else if (soc_is_exynos5250())
 171                 ret = exynos5250_cpufreq_init(exynos_info);
 172         else
 173                 return 0;
 174
 175         if (ret)
 176                 goto err_vdd_arm;
 177
 178         if (exynos_info->set_freq == NULL) {
 179                 pr_err("%s: No set_freq function (ERR)\n", __func__);
 180                 goto err_vdd_arm;
 181         }
 182
 183         arm_regulator = regulator_get(NULL, "vdd_arm");
 184         if (IS_ERR(arm_regulator)) {
 185                 pr_err("%s: failed to get resource vdd_arm\n", __func__);
 186                 goto err_vdd_arm;
 187         }
 188
 189         /* Done here as we want to capture boot frequency */
 190         locking_frequency = clk_get_rate(exynos_info->cpu_clk) / 1000;
 191
 192         if (!cpufreq_register_driver(&exynos_driver))
 193                 return 0;
 194
 195         pr_err("%s: failed to register cpufreq driver\n", __func__);
 196         regulator_put(arm_regulator);
 197 err_vdd_arm:
 198         kfree(exynos_info);
 199         return -EINVAL;
 200 }
 201
 202 static struct platform_driver exynos_cpufreq_platdrv = {
 203         .driver = {
 204                 .name   = "exynos-cpufreq",
 205                 .owner  = THIS_MODULE,
 206         },
 207         .probe = exynos_cpufreq_probe,
 208 };
 209 module_platform_driver(exynos_cpufreq_platdrv);