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/module.h>
  14 #include <linux/err.h>
  15 #include <linux/clk.h>
  16 #include <linux/io.h>
  17 #include <linux/slab.h>
  18 #include <linux/regulator/consumer.h>
  19 #include <linux/cpufreq.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/of.h>
  22 #include <linux/cpu_cooling.h>
  23 #include <linux/cpu.h>
  24
  25 #include "exynos-cpufreq.h"
  26
  27 static struct exynos_dvfs_info *exynos_info;
  28 static struct thermal_cooling_device *cdev;
  29 static struct regulator *arm_regulator;
  30 static unsigned int locking_frequency;
  31
  32 static int exynos_cpufreq_get_index(unsigned int freq)
  33 {
  34         struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
  35         struct cpufreq_frequency_table *pos;
  36
  37         cpufreq_for_each_entry(pos, freq_table)
  38                 if (pos->frequency == freq)
  39                         break;
  40
  41         if (pos->frequency == CPUFREQ_TABLE_END)
  42                 return -EINVAL;
  43
  44         return pos - freq_table;
  45 }
  46
  47 static int exynos_cpufreq_scale(unsigned int target_freq)
  48 {
  49         struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
  50         unsigned int *volt_table = exynos_info->volt_table;
  51         struct cpufreq_policy *policy = cpufreq_cpu_get(0);
  52         unsigned int arm_volt, safe_arm_volt = 0;
  53         unsigned int mpll_freq_khz = exynos_info->mpll_freq_khz;
  54         struct device *dev = exynos_info->dev;
  55         unsigned int old_freq;
  56         int index, old_index;
  57         int ret = 0;
  58
  59         old_freq = policy->cur;
  60
  61         /*
  62          * The policy max have been changed so that we cannot get proper
  63          * old_index with cpufreq_frequency_table_target(). Thus, ignore
  64          * policy and get the index from the raw frequency table.
  65          */
  66         old_index = exynos_cpufreq_get_index(old_freq);
  67         if (old_index < 0) {
  68                 ret = old_index;
  69                 goto out;
  70         }
  71
  72         index = exynos_cpufreq_get_index(target_freq);
  73         if (index < 0) {
  74                 ret = index;
  75                 goto out;
  76         }
  77
  78         /*
  79          * ARM clock source will be changed APLL to MPLL temporary
  80          * To support this level, need to control regulator for
  81          * required voltage level
  82          */
  83         if (exynos_info->need_apll_change != NULL) {
  84                 if (exynos_info->need_apll_change(old_index, index) &&
  85                    (freq_table[index].frequency < mpll_freq_khz) &&
  86                    (freq_table[old_index].frequency < mpll_freq_khz))
  87                         safe_arm_volt = volt_table[exynos_info->pll_safe_idx];
  88         }
  89         arm_volt = volt_table[index];
  90
  91         /* When the new frequency is higher than current frequency */
  92         if ((target_freq > old_freq) && !safe_arm_volt) {
  93                 /* Firstly, voltage up to increase frequency */
  94                 ret = regulator_set_voltage(arm_regulator, arm_volt, arm_volt);
  95                 if (ret) {
  96                         dev_err(dev, "failed to set cpu voltage to %d\n",
  97                                 arm_volt);
  98                         return ret;
  99                 }
 100         }
 101
 102         if (safe_arm_volt) {
 103                 ret = regulator_set_voltage(arm_regulator, safe_arm_volt,
 104                                       safe_arm_volt);
 105                 if (ret) {
 106                         dev_err(dev, "failed to set cpu voltage to %d\n",
 107                                 safe_arm_volt);
 108                         return ret;
 109                 }
 110         }
 111
 112         exynos_info->set_freq(old_index, index);
 113
 114         /* When the new frequency is lower than current frequency */
 115         if ((target_freq < old_freq) ||
 116            ((target_freq > old_freq) && safe_arm_volt)) {
 117                 /* down the voltage after frequency change */
 118                 ret = regulator_set_voltage(arm_regulator, arm_volt,
 119                                 arm_volt);
 120                 if (ret) {
 121                         dev_err(dev, "failed to set cpu voltage to %d\n",
 122                                 arm_volt);
 123                         goto out;
 124                 }
 125         }
 126
 127 out:
 128         cpufreq_cpu_put(policy);
 129
 130         return ret;
 131 }
 132
 133 static int exynos_target(struct cpufreq_policy *policy, unsigned int index)
 134 {
 135         return exynos_cpufreq_scale(exynos_info->freq_table[index].frequency);
 136 }
 137
 138 static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
 139 {
 140         policy->clk = exynos_info->cpu_clk;
 141         policy->suspend_freq = locking_frequency;
 142         return cpufreq_generic_init(policy, exynos_info->freq_table, 100000);
 143 }
 144
 145 static struct cpufreq_driver exynos_driver = {
 146         .flags          = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 147         .verify         = cpufreq_generic_frequency_table_verify,
 148         .target_index   = exynos_target,
 149         .get            = cpufreq_generic_get,
 150         .init           = exynos_cpufreq_cpu_init,
 151         .name           = "exynos_cpufreq",
 152         .attr           = cpufreq_generic_attr,
 153 #ifdef CONFIG_ARM_EXYNOS_CPU_FREQ_BOOST_SW
 154         .boost_supported = true,
 155 #endif
 156 #ifdef CONFIG_PM
 157         .suspend        = cpufreq_generic_suspend,
 158 #endif
 159 };
 160
 161 static int exynos_cpufreq_probe(struct platform_device *pdev)
 162 {
 163         struct device_node *cpu0;
 164         int ret = -EINVAL;
 165
 166         exynos_info = kzalloc(sizeof(*exynos_info), GFP_KERNEL);
 167         if (!exynos_info)
 168                 return -ENOMEM;
 169
 170         exynos_info->dev = &pdev->dev;
 171
 172         if (of_machine_is_compatible("samsung,exynos4212")) {
 173                 exynos_info->type = EXYNOS_SOC_4212;
 174                 ret = exynos4x12_cpufreq_init(exynos_info);
 175         } else if (of_machine_is_compatible("samsung,exynos4412")) {
 176                 exynos_info->type = EXYNOS_SOC_4412;
 177                 ret = exynos4x12_cpufreq_init(exynos_info);
 178         } else {
 179                 pr_err("%s: Unknown SoC type\n", __func__);
 180                 return -ENODEV;
 181         }
 182
 183         if (ret)
 184                 goto err_vdd_arm;
 185
 186         if (exynos_info->set_freq == NULL) {
 187                 dev_err(&pdev->dev, "No set_freq function (ERR)\n");
 188                 goto err_vdd_arm;
 189         }
 190
 191         arm_regulator = regulator_get(NULL, "vdd_arm");
 192         if (IS_ERR(arm_regulator)) {
 193                 dev_err(&pdev->dev, "failed to get resource vdd_arm\n");
 194                 goto err_vdd_arm;
 195         }
 196
 197         /* Done here as we want to capture boot frequency */
 198         locking_frequency = clk_get_rate(exynos_info->cpu_clk) / 1000;
 199
 200         ret = cpufreq_register_driver(&exynos_driver);
 201         if (ret)
 202                 goto err_cpufreq_reg;
 203
 204         cpu0 = of_get_cpu_node(0, NULL);
 205         if (!cpu0) {
 206                 pr_err("failed to find cpu0 node\n");
 207                 return 0;
 208         }
 209
 210         if (of_find_property(cpu0, "#cooling-cells", NULL)) {
 211                 cdev = of_cpufreq_cooling_register(cpu0,
 212                                                    cpu_present_mask);
 213                 if (IS_ERR(cdev))
 214                         pr_err("running cpufreq without cooling device: %ld\n",
 215                                PTR_ERR(cdev));
 216         }
 217
 218         return 0;
 219
 220 err_cpufreq_reg:
 221         dev_err(&pdev->dev, "failed to register cpufreq driver\n");
 222         regulator_put(arm_regulator);
 223 err_vdd_arm:
 224         kfree(exynos_info);
 225         return -EINVAL;
 226 }
 227
 228 static struct platform_driver exynos_cpufreq_platdrv = {
 229         .driver = {
 230                 .name   = "exynos-cpufreq",
 231         },
 232         .probe = exynos_cpufreq_probe,
 233 };
 234 module_platform_driver(exynos_cpufreq_platdrv);