linux/drivers/cpufreq/exynos-cpufreq.c
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   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 <plat/cpu.h>
  22
  23#include "exynos-cpufreq.h"
  24
  25static struct exynos_dvfs_info *exynos_info;
  26
  27static struct regulator *arm_regulator;
  28static struct cpufreq_freqs freqs;
  29
  30static unsigned int locking_frequency;
  31static bool frequency_locked;
  32static DEFINE_MUTEX(cpufreq_lock);
  33
  34static int exynos_verify_speed(struct cpufreq_policy *policy)
  35{
  36        return cpufreq_frequency_table_verify(policy,
  37                                              exynos_info->freq_table);
  38}
  39
  40static unsigned int exynos_getspeed(unsigned int cpu)
  41{
  42        return clk_get_rate(exynos_info->cpu_clk) / 1000;
  43}
  44
  45static int exynos_cpufreq_get_index(unsigned int freq)
  46{
  47        struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
  48        int index;
  49
  50        for (index = 0;
  51                freq_table[index].frequency != CPUFREQ_TABLE_END; index++)
  52                if (freq_table[index].frequency == freq)
  53                        break;
  54
  55        if (freq_table[index].frequency == CPUFREQ_TABLE_END)
  56                return -EINVAL;
  57
  58        return index;
  59}
  60
  61static int exynos_cpufreq_scale(unsigned int target_freq)
  62{
  63        struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
  64        unsigned int *volt_table = exynos_info->volt_table;
  65        struct cpufreq_policy *policy = cpufreq_cpu_get(0);
  66        unsigned int arm_volt, safe_arm_volt = 0;
  67        unsigned int mpll_freq_khz = exynos_info->mpll_freq_khz;
  68        int index, old_index;
  69        int ret = 0;
  70
  71        freqs.old = policy->cur;
  72        freqs.new = target_freq;
  73        freqs.cpu = policy->cpu;
  74
  75        if (freqs.new == freqs.old)
  76                goto out;
  77
  78        /*
  79         * The policy max have been changed so that we cannot get proper
  80         * old_index with cpufreq_frequency_table_target(). Thus, ignore
  81         * policy and get the index from the raw freqeuncy table.
  82         */
  83        old_index = exynos_cpufreq_get_index(freqs.old);
  84        if (old_index < 0) {
  85                ret = old_index;
  86                goto out;
  87        }
  88
  89        index = exynos_cpufreq_get_index(target_freq);
  90        if (index < 0) {
  91                ret = index;
  92                goto out;
  93        }
  94
  95        /*
  96         * ARM clock source will be changed APLL to MPLL temporary
  97         * To support this level, need to control regulator for
  98         * required voltage level
  99         */
 100        if (exynos_info->need_apll_change != NULL) {
 101                if (exynos_info->need_apll_change(old_index, index) &&
 102                   (freq_table[index].frequency < mpll_freq_khz) &&
 103                   (freq_table[old_index].frequency < mpll_freq_khz))
 104                        safe_arm_volt = volt_table[exynos_info->pll_safe_idx];
 105        }
 106        arm_volt = volt_table[index];
 107
 108        for_each_cpu(freqs.cpu, policy->cpus)
 109                cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 110
 111        /* When the new frequency is higher than current frequency */
 112        if ((freqs.new > freqs.old) && !safe_arm_volt) {
 113                /* Firstly, voltage up to increase frequency */
 114                ret = regulator_set_voltage(arm_regulator, arm_volt, arm_volt);
 115                if (ret) {
 116                        pr_err("%s: failed to set cpu voltage to %d\n",
 117                                __func__, arm_volt);
 118                        goto out;
 119                }
 120        }
 121
 122        if (safe_arm_volt) {
 123                ret = regulator_set_voltage(arm_regulator, safe_arm_volt,
 124                                      safe_arm_volt);
 125                if (ret) {
 126                        pr_err("%s: failed to set cpu voltage to %d\n",
 127                                __func__, safe_arm_volt);
 128                        goto out;
 129                }
 130        }
 131
 132        exynos_info->set_freq(old_index, index);
 133
 134        for_each_cpu(freqs.cpu, policy->cpus)
 135                cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 136
 137        /* When the new frequency is lower than current frequency */
 138        if ((freqs.new < freqs.old) ||
 139           ((freqs.new > freqs.old) && safe_arm_volt)) {
 140                /* down the voltage after frequency change */
 141                regulator_set_voltage(arm_regulator, arm_volt,
 142                                arm_volt);
 143                if (ret) {
 144                        pr_err("%s: failed to set cpu voltage to %d\n",
 145                                __func__, arm_volt);
 146                        goto out;
 147                }
 148        }
 149
 150out:
 151
 152        cpufreq_cpu_put(policy);
 153
 154        return ret;
 155}
 156
 157static int exynos_target(struct cpufreq_policy *policy,
 158                          unsigned int target_freq,
 159                          unsigned int relation)
 160{
 161        struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
 162        unsigned int index;
 163        unsigned int new_freq;
 164        int ret = 0;
 165
 166        mutex_lock(&cpufreq_lock);
 167
 168        if (frequency_locked)
 169                goto out;
 170
 171        if (cpufreq_frequency_table_target(policy, freq_table,
 172                                           target_freq, relation, &index)) {
 173                ret = -EINVAL;
 174                goto out;
 175        }
 176
 177        new_freq = freq_table[index].frequency;
 178
 179        ret = exynos_cpufreq_scale(new_freq);
 180
 181out:
 182        mutex_unlock(&cpufreq_lock);
 183
 184        return ret;
 185}
 186
 187#ifdef CONFIG_PM
 188static int exynos_cpufreq_suspend(struct cpufreq_policy *policy)
 189{
 190        return 0;
 191}
 192
 193static int exynos_cpufreq_resume(struct cpufreq_policy *policy)
 194{
 195        return 0;
 196}
 197#endif
 198
 199/**
 200 * exynos_cpufreq_pm_notifier - block CPUFREQ's activities in suspend-resume
 201 *                      context
 202 * @notifier
 203 * @pm_event
 204 * @v
 205 *
 206 * While frequency_locked == true, target() ignores every frequency but
 207 * locking_frequency. The locking_frequency value is the initial frequency,
 208 * which is set by the bootloader. In order to eliminate possible
 209 * inconsistency in clock values, we save and restore frequencies during
 210 * suspend and resume and block CPUFREQ activities. Note that the standard
 211 * suspend/resume cannot be used as they are too deep (syscore_ops) for
 212 * regulator actions.
 213 */
 214static int exynos_cpufreq_pm_notifier(struct notifier_block *notifier,
 215                                       unsigned long pm_event, void *v)
 216{
 217        int ret;
 218
 219        switch (pm_event) {
 220        case PM_SUSPEND_PREPARE:
 221                mutex_lock(&cpufreq_lock);
 222                frequency_locked = true;
 223                mutex_unlock(&cpufreq_lock);
 224
 225                ret = exynos_cpufreq_scale(locking_frequency);
 226                if (ret < 0)
 227                        return NOTIFY_BAD;
 228
 229                break;
 230
 231        case PM_POST_SUSPEND:
 232                mutex_lock(&cpufreq_lock);
 233                frequency_locked = false;
 234                mutex_unlock(&cpufreq_lock);
 235                break;
 236        }
 237
 238        return NOTIFY_OK;
 239}
 240
 241static struct notifier_block exynos_cpufreq_nb = {
 242        .notifier_call = exynos_cpufreq_pm_notifier,
 243};
 244
 245static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
 246{
 247        policy->cur = policy->min = policy->max = exynos_getspeed(policy->cpu);
 248
 249        cpufreq_frequency_table_get_attr(exynos_info->freq_table, policy->cpu);
 250
 251        /* set the transition latency value */
 252        policy->cpuinfo.transition_latency = 100000;
 253
 254        cpumask_setall(policy->cpus);
 255
 256        return cpufreq_frequency_table_cpuinfo(policy, exynos_info->freq_table);
 257}
 258
 259static int exynos_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 260{
 261        cpufreq_frequency_table_put_attr(policy->cpu);
 262        return 0;
 263}
 264
 265static struct freq_attr *exynos_cpufreq_attr[] = {
 266        &cpufreq_freq_attr_scaling_available_freqs,
 267        NULL,
 268};
 269
 270static struct cpufreq_driver exynos_driver = {
 271        .flags          = CPUFREQ_STICKY,
 272        .verify         = exynos_verify_speed,
 273        .target         = exynos_target,
 274        .get            = exynos_getspeed,
 275        .init           = exynos_cpufreq_cpu_init,
 276        .exit           = exynos_cpufreq_cpu_exit,
 277        .name           = "exynos_cpufreq",
 278        .attr           = exynos_cpufreq_attr,
 279#ifdef CONFIG_PM
 280        .suspend        = exynos_cpufreq_suspend,
 281        .resume         = exynos_cpufreq_resume,
 282#endif
 283};
 284
 285static int __init exynos_cpufreq_init(void)
 286{
 287        int ret = -EINVAL;
 288
 289        exynos_info = kzalloc(sizeof(struct exynos_dvfs_info), GFP_KERNEL);
 290        if (!exynos_info)
 291                return -ENOMEM;
 292
 293        if (soc_is_exynos4210())
 294                ret = exynos4210_cpufreq_init(exynos_info);
 295        else if (soc_is_exynos4212() || soc_is_exynos4412())
 296                ret = exynos4x12_cpufreq_init(exynos_info);
 297        else if (soc_is_exynos5250())
 298                ret = exynos5250_cpufreq_init(exynos_info);
 299        else
 300                pr_err("%s: CPU type not found\n", __func__);
 301
 302        if (ret)
 303                goto err_vdd_arm;
 304
 305        if (exynos_info->set_freq == NULL) {
 306                pr_err("%s: No set_freq function (ERR)\n", __func__);
 307                goto err_vdd_arm;
 308        }
 309
 310        arm_regulator = regulator_get(NULL, "vdd_arm");
 311        if (IS_ERR(arm_regulator)) {
 312                pr_err("%s: failed to get resource vdd_arm\n", __func__);
 313                goto err_vdd_arm;
 314        }
 315
 316        locking_frequency = exynos_getspeed(0);
 317
 318        register_pm_notifier(&exynos_cpufreq_nb);
 319
 320        if (cpufreq_register_driver(&exynos_driver)) {
 321                pr_err("%s: failed to register cpufreq driver\n", __func__);
 322                goto err_cpufreq;
 323        }
 324
 325        return 0;
 326err_cpufreq:
 327        unregister_pm_notifier(&exynos_cpufreq_nb);
 328
 329        regulator_put(arm_regulator);
 330err_vdd_arm:
 331        kfree(exynos_info);
 332        pr_debug("%s: failed initialization\n", __func__);
 333        return -EINVAL;
 334}
 335late_initcall(exynos_cpufreq_init);
 336
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