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 #include <linux/of.h>
  21 #include <linux/cpu_cooling.h>
  22 #include <linux/cpu.h>
  23
  24 #include "exynos-cpufreq.h"
  25
  26 static struct exynos_dvfs_info *exynos_info;
  27 static struct thermal_cooling_device *cdev;
  28 static struct regulator *arm_regulator;
  29 static unsigned int locking_frequency;
  30
  31 static int exynos_cpufreq_get_index(unsigned int freq)
  32 {
  33         struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
  34         struct cpufreq_frequency_table *pos;
  35
  36         cpufreq_for_each_entry(pos, freq_table)
  37                 if (pos->frequency == freq)
  38                         break;
  39
  40         if (pos->frequency == CPUFREQ_TABLE_END)
  41                 return -EINVAL;
  42
  43         return pos - freq_table;
  44 }
  45
  46 static int exynos_cpufreq_scale(unsigned int target_freq)
  47 {
  48         struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
  49         unsigned int *volt_table = exynos_info->volt_table;
  50         struct cpufreq_policy *policy = cpufreq_cpu_get(0);
  51         unsigned int arm_volt, safe_arm_volt = 0;
  52         unsigned int mpll_freq_khz = exynos_info->mpll_freq_khz;
  53         struct device *dev = exynos_info->dev;
  54         unsigned int old_freq;
  55         int index, old_index;
  56         int ret = 0;
  57
  58         old_freq = policy->cur;
  59
  60         /*
  61          * The policy max have been changed so that we cannot get proper
  62          * old_index with cpufreq_frequency_table_target(). Thus, ignore
  63          * policy and get the index from the raw frequency table.
  64          */
  65         old_index = exynos_cpufreq_get_index(old_freq);
  66         if (old_index < 0) {
  67                 ret = old_index;
  68                 goto out;
  69         }
  70
  71         index = exynos_cpufreq_get_index(target_freq);
  72         if (index < 0) {
  73                 ret = index;
  74                 goto out;
  75         }
  76
  77         /*
  78          * ARM clock source will be changed APLL to MPLL temporary
  79          * To support this level, need to control regulator for
  80          * required voltage level
  81          */
  82         if (exynos_info->need_apll_change != NULL) {
  83                 if (exynos_info->need_apll_change(old_index, index) &&
  84                    (freq_table[index].frequency < mpll_freq_khz) &&
  85                    (freq_table[old_index].frequency < mpll_freq_khz))
  86                         safe_arm_volt = volt_table[exynos_info->pll_safe_idx];
  87         }
  88         arm_volt = volt_table[index];
  89
  90         /* When the new frequency is higher than current frequency */
  91         if ((target_freq > old_freq) && !safe_arm_volt) {
  92                 /* Firstly, voltage up to increase frequency */
  93                 ret = regulator_set_voltage(arm_regulator, arm_volt, arm_volt);
  94                 if (ret) {
  95                         dev_err(dev, "failed to set cpu voltage to %d\n",
  96                                 arm_volt);
  97                         return ret;
  98                 }
  99         }
 100
 101         if (safe_arm_volt) {
 102                 ret = regulator_set_voltage(arm_regulator, safe_arm_volt,
 103                                       safe_arm_volt);
 104                 if (ret) {
 105                         dev_err(dev, "failed to set cpu voltage to %d\n",
 106                                 safe_arm_volt);
 107                         return ret;
 108                 }
 109         }
 110
 111         exynos_info->set_freq(old_index, index);
 112
 113         /* When the new frequency is lower than current frequency */
 114         if ((target_freq < old_freq) ||
 115            ((target_freq > old_freq) && safe_arm_volt)) {
 116                 /* down the voltage after frequency change */
 117                 ret = regulator_set_voltage(arm_regulator, arm_volt,
 118                                 arm_volt);
 119                 if (ret) {
 120                         dev_err(dev, "failed to set cpu voltage to %d\n",
 121                                 arm_volt);
 122                         goto out;
 123                 }
 124         }
 125
 126 out:
 127         cpufreq_cpu_put(policy);
 128
 129         return ret;
 130 }
 131
 132 static int exynos_target(struct cpufreq_policy *policy, unsigned int index)
 133 {
 134         return exynos_cpufreq_scale(exynos_info->freq_table[index].frequency);
 135 }
 136
 137 static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
 138 {
 139         policy->clk = exynos_info->cpu_clk;
 140         policy->suspend_freq = locking_frequency;
 141         return cpufreq_generic_init(policy, exynos_info->freq_table, 100000);
 142 }
 143
 144 static struct cpufreq_driver exynos_driver = {
 145         .flags          = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 146         .verify         = cpufreq_generic_frequency_table_verify,
 147         .target_index   = exynos_target,
 148         .get            = cpufreq_generic_get,
 149         .init           = exynos_cpufreq_cpu_init,
 150         .name           = "exynos_cpufreq",
 151         .attr           = cpufreq_generic_attr,
 152 #ifdef CONFIG_ARM_EXYNOS_CPU_FREQ_BOOST_SW
 153         .boost_supported = true,
 154 #endif
 155 #ifdef CONFIG_PM
 156         .suspend        = cpufreq_generic_suspend,
 157 #endif
 158 };
 159
 160 static int exynos_cpufreq_probe(struct platform_device *pdev)
 161 {
 162         struct device_node *cpus, *np;
 163         int ret = -EINVAL;
 164
 165         exynos_info = kzalloc(sizeof(*exynos_info), GFP_KERNEL);
 166         if (!exynos_info)
 167                 return -ENOMEM;
 168
 169         exynos_info->dev = &pdev->dev;
 170
 171         if (of_machine_is_compatible("samsung,exynos4210")) {
 172                 exynos_info->type = EXYNOS_SOC_4210;
 173                 ret = exynos4210_cpufreq_init(exynos_info);
 174         } else if (of_machine_is_compatible("samsung,exynos4212")) {
 175                 exynos_info->type = EXYNOS_SOC_4212;
 176                 ret = exynos4x12_cpufreq_init(exynos_info);
 177         } else if (of_machine_is_compatible("samsung,exynos4412")) {
 178                 exynos_info->type = EXYNOS_SOC_4412;
 179                 ret = exynos4x12_cpufreq_init(exynos_info);
 180         } else if (of_machine_is_compatible("samsung,exynos5250")) {
 181                 exynos_info->type = EXYNOS_SOC_5250;
 182                 ret = exynos5250_cpufreq_init(exynos_info);
 183         } else {
 184                 pr_err("%s: Unknown SoC type\n", __func__);
 185                 return -ENODEV;
 186         }
 187
 188         if (ret)
 189                 goto err_vdd_arm;
 190
 191         if (exynos_info->set_freq == NULL) {
 192                 dev_err(&pdev->dev, "No set_freq function (ERR)\n");
 193                 goto err_vdd_arm;
 194         }
 195
 196         arm_regulator = regulator_get(NULL, "vdd_arm");
 197         if (IS_ERR(arm_regulator)) {
 198                 dev_err(&pdev->dev, "failed to get resource vdd_arm\n");
 199                 goto err_vdd_arm;
 200         }
 201
 202         /* Done here as we want to capture boot frequency */
 203         locking_frequency = clk_get_rate(exynos_info->cpu_clk) / 1000;
 204
 205         ret = cpufreq_register_driver(&exynos_driver);
 206         if (ret)
 207                 goto err_cpufreq_reg;
 208
 209         cpus = of_find_node_by_path("/cpus");
 210         if (!cpus) {
 211                 pr_err("failed to find cpus node\n");
 212                 return 0;
 213         }
 214
 215         np = of_get_next_child(cpus, NULL);
 216         if (!np) {
 217                 pr_err("failed to find cpus child node\n");
 218                 of_node_put(cpus);
 219                 return 0;
 220         }
 221
 222         if (of_find_property(np, "#cooling-cells", NULL)) {
 223                 cdev = of_cpufreq_cooling_register(np,
 224                                                    cpu_present_mask);
 225                 if (IS_ERR(cdev))
 226                         pr_err("running cpufreq without cooling device: %ld\n",
 227                                PTR_ERR(cdev));
 228         }
 229         of_node_put(np);
 230         of_node_put(cpus);
 231
 232         return 0;
 233
 234 err_cpufreq_reg:
 235         dev_err(&pdev->dev, "failed to register cpufreq driver\n");
 236         regulator_put(arm_regulator);
 237 err_vdd_arm:
 238         kfree(exynos_info);
 239         return -EINVAL;
 240 }
 241
 242 static struct platform_driver exynos_cpufreq_platdrv = {
 243         .driver = {
 244                 .name   = "exynos-cpufreq",
 245         },
 246         .probe = exynos_cpufreq_probe,
 247 };
 248 module_platform_driver(exynos_cpufreq_platdrv);