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
  21 #include <mach/cpufreq.h>
  22
  23 #include <plat/cpu.h>
  24
  25 static struct exynos_dvfs_info *exynos_info;
  26
  27 static struct regulator *arm_regulator;
  28 static struct cpufreq_freqs freqs;
  29
  30 static unsigned int locking_frequency;
  31 static bool frequency_locked;
  32 static DEFINE_MUTEX(cpufreq_lock);
  33
  34 static int exynos_verify_speed(struct cpufreq_policy *policy)
  35 {
  36         return cpufreq_frequency_table_verify(policy,
  37                                               exynos_info->freq_table);
  38 }
  39
  40 static unsigned int exynos_getspeed(unsigned int cpu)
  41 {
  42         return clk_get_rate(exynos_info->cpu_clk) / 1000;
  43 }
  44
  45 static int exynos_target(struct cpufreq_policy *policy,
  46                           unsigned int target_freq,
  47                           unsigned int relation)
  48 {
  49         unsigned int index, old_index;
  50         unsigned int arm_volt, safe_arm_volt = 0;
  51         int ret = 0;
  52         struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
  53         unsigned int *volt_table = exynos_info->volt_table;
  54         unsigned int mpll_freq_khz = exynos_info->mpll_freq_khz;
  55
  56         mutex_lock(&cpufreq_lock);
  57
  58         freqs.old = policy->cur;
  59
  60         if (frequency_locked && target_freq != locking_frequency) {
  61                 ret = -EAGAIN;
  62                 goto out;
  63         }
  64
  65         /*
  66          * The policy max have been changed so that we cannot get proper
  67          * old_index with cpufreq_frequency_table_target(). Thus, ignore
  68          * policy and get the index from the raw freqeuncy table.
  69          */
  70         for (old_index = 0;
  71                 freq_table[old_index].frequency != CPUFREQ_TABLE_END;
  72                 old_index++)
  73                 if (freq_table[old_index].frequency == freqs.old)
  74                         break;
  75
  76         if (freq_table[old_index].frequency == CPUFREQ_TABLE_END) {
  77                 ret = -EINVAL;
  78                 goto out;
  79         }
  80
  81         if (cpufreq_frequency_table_target(policy, freq_table,
  82                                            target_freq, relation, &index)) {
  83                 ret = -EINVAL;
  84                 goto out;
  85         }
  86
  87         freqs.new = freq_table[index].frequency;
  88         freqs.cpu = policy->cpu;
  89
  90         if (freqs.new == freqs.old)
  91                 goto out;
  92
  93         /*
  94          * ARM clock source will be changed APLL to MPLL temporary
  95          * To support this level, need to control regulator for
  96          * required voltage level
  97          */
  98         if (exynos_info->need_apll_change != NULL) {
  99                 if (exynos_info->need_apll_change(old_index, index) &&
 100                    (freq_table[index].frequency < mpll_freq_khz) &&
 101                    (freq_table[old_index].frequency < mpll_freq_khz))
 102                         safe_arm_volt = volt_table[exynos_info->pll_safe_idx];
 103         }
 104         arm_volt = volt_table[index];
 105
 106         for_each_cpu(freqs.cpu, policy->cpus)
 107                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 108
 109         /* When the new frequency is higher than current frequency */
 110         if ((freqs.new > freqs.old) && !safe_arm_volt) {
 111                 /* Firstly, voltage up to increase frequency */
 112                 regulator_set_voltage(arm_regulator, arm_volt,
 113                                 arm_volt);
 114         }
 115
 116         if (safe_arm_volt)
 117                 regulator_set_voltage(arm_regulator, safe_arm_volt,
 118                                       safe_arm_volt);
 119
 120         exynos_info->set_freq(old_index, index);
 121
 122         for_each_cpu(freqs.cpu, policy->cpus)
 123                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 124
 125         /* When the new frequency is lower than current frequency */
 126         if ((freqs.new < freqs.old) ||
 127            ((freqs.new > freqs.old) && safe_arm_volt)) {
 128                 /* down the voltage after frequency change */
 129                 regulator_set_voltage(arm_regulator, arm_volt,
 130                                 arm_volt);
 131         }
 132
 133 out:
 134         mutex_unlock(&cpufreq_lock);
 135
 136         return ret;
 137 }
 138
 139 #ifdef CONFIG_PM
 140 static int exynos_cpufreq_suspend(struct cpufreq_policy *policy)
 141 {
 142         return 0;
 143 }
 144
 145 static int exynos_cpufreq_resume(struct cpufreq_policy *policy)
 146 {
 147         return 0;
 148 }
 149 #endif
 150
 151 /**
 152  * exynos_cpufreq_pm_notifier - block CPUFREQ's activities in suspend-resume
 153  *                      context
 154  * @notifier
 155  * @pm_event
 156  * @v
 157  *
 158  * While frequency_locked == true, target() ignores every frequency but
 159  * locking_frequency. The locking_frequency value is the initial frequency,
 160  * which is set by the bootloader. In order to eliminate possible
 161  * inconsistency in clock values, we save and restore frequencies during
 162  * suspend and resume and block CPUFREQ activities. Note that the standard
 163  * suspend/resume cannot be used as they are too deep (syscore_ops) for
 164  * regulator actions.
 165  */
 166 static int exynos_cpufreq_pm_notifier(struct notifier_block *notifier,
 167                                        unsigned long pm_event, void *v)
 168 {
 169         struct cpufreq_policy *policy = cpufreq_cpu_get(0); /* boot CPU */
 170         static unsigned int saved_frequency;
 171         unsigned int temp;
 172
 173         mutex_lock(&cpufreq_lock);
 174         switch (pm_event) {
 175         case PM_SUSPEND_PREPARE:
 176                 if (frequency_locked)
 177                         goto out;
 178
 179                 frequency_locked = true;
 180
 181                 if (locking_frequency) {
 182                         saved_frequency = exynos_getspeed(0);
 183
 184                         mutex_unlock(&cpufreq_lock);
 185                         exynos_target(policy, locking_frequency,
 186                                       CPUFREQ_RELATION_H);
 187                         mutex_lock(&cpufreq_lock);
 188                 }
 189                 break;
 190
 191         case PM_POST_SUSPEND:
 192                 if (saved_frequency) {
 193                         /*
 194                          * While frequency_locked, only locking_frequency
 195                          * is valid for target(). In order to use
 196                          * saved_frequency while keeping frequency_locked,
 197                          * we temporarly overwrite locking_frequency.
 198                          */
 199                         temp = locking_frequency;
 200                         locking_frequency = saved_frequency;
 201
 202                         mutex_unlock(&cpufreq_lock);
 203                         exynos_target(policy, locking_frequency,
 204                                       CPUFREQ_RELATION_H);
 205                         mutex_lock(&cpufreq_lock);
 206
 207                         locking_frequency = temp;
 208                 }
 209                 frequency_locked = false;
 210                 break;
 211         }
 212 out:
 213         mutex_unlock(&cpufreq_lock);
 214
 215         return NOTIFY_OK;
 216 }
 217
 218 static struct notifier_block exynos_cpufreq_nb = {
 219         .notifier_call = exynos_cpufreq_pm_notifier,
 220 };
 221
 222 static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
 223 {
 224         policy->cur = policy->min = policy->max = exynos_getspeed(policy->cpu);
 225
 226         cpufreq_frequency_table_get_attr(exynos_info->freq_table, policy->cpu);
 227
 228         locking_frequency = exynos_getspeed(0);
 229
 230         /* set the transition latency value */
 231         policy->cpuinfo.transition_latency = 100000;
 232
 233         /*
 234          * EXYNOS4 multi-core processors has 2 cores
 235          * that the frequency cannot be set independently.
 236          * Each cpu is bound to the same speed.
 237          * So the affected cpu is all of the cpus.
 238          */
 239         if (num_online_cpus() == 1) {
 240                 cpumask_copy(policy->related_cpus, cpu_possible_mask);
 241                 cpumask_copy(policy->cpus, cpu_online_mask);
 242         } else {
 243                 policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
 244                 cpumask_setall(policy->cpus);
 245         }
 246
 247         return cpufreq_frequency_table_cpuinfo(policy, exynos_info->freq_table);
 248 }
 249
 250 static struct cpufreq_driver exynos_driver = {
 251         .flags          = CPUFREQ_STICKY,
 252         .verify         = exynos_verify_speed,
 253         .target         = exynos_target,
 254         .get            = exynos_getspeed,
 255         .init           = exynos_cpufreq_cpu_init,
 256         .name           = "exynos_cpufreq",
 257 #ifdef CONFIG_PM
 258         .suspend        = exynos_cpufreq_suspend,
 259         .resume         = exynos_cpufreq_resume,
 260 #endif
 261 };
 262
 263 static int __init exynos_cpufreq_init(void)
 264 {
 265         int ret = -EINVAL;
 266
 267         exynos_info = kzalloc(sizeof(struct exynos_dvfs_info), GFP_KERNEL);
 268         if (!exynos_info)
 269                 return -ENOMEM;
 270
 271         if (soc_is_exynos4210())
 272                 ret = exynos4210_cpufreq_init(exynos_info);
 273         else if (soc_is_exynos4212() || soc_is_exynos4412())
 274                 ret = exynos4x12_cpufreq_init(exynos_info);
 275         else if (soc_is_exynos5250())
 276                 ret = exynos5250_cpufreq_init(exynos_info);
 277         else
 278                 pr_err("%s: CPU type not found\n", __func__);
 279
 280         if (ret)
 281                 goto err_vdd_arm;
 282
 283         if (exynos_info->set_freq == NULL) {
 284                 pr_err("%s: No set_freq function (ERR)\n", __func__);
 285                 goto err_vdd_arm;
 286         }
 287
 288         arm_regulator = regulator_get(NULL, "vdd_arm");
 289         if (IS_ERR(arm_regulator)) {
 290                 pr_err("%s: failed to get resource vdd_arm\n", __func__);
 291                 goto err_vdd_arm;
 292         }
 293
 294         register_pm_notifier(&exynos_cpufreq_nb);
 295
 296         if (cpufreq_register_driver(&exynos_driver)) {
 297                 pr_err("%s: failed to register cpufreq driver\n", __func__);
 298                 goto err_cpufreq;
 299         }
 300
 301         return 0;
 302 err_cpufreq:
 303         unregister_pm_notifier(&exynos_cpufreq_nb);
 304
 305         regulator_put(arm_regulator);
 306 err_vdd_arm:
 307         kfree(exynos_info);
 308         pr_debug("%s: failed initialization\n", __func__);
 309         return -EINVAL;
 310 }
 311 late_initcall(exynos_cpufreq_init);