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Linux/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);
210 

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