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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 #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 *cpu0;
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         cpu0 = of_get_cpu_node(0, NULL);
210         if (!cpu0) {
211                 pr_err("failed to find cpu0 node\n");
212                 return 0;
213         }
214 
215         if (of_find_property(cpu0, "#cooling-cells", NULL)) {
216                 cdev = of_cpufreq_cooling_register(cpu0,
217                                                    cpu_present_mask);
218                 if (IS_ERR(cdev))
219                         pr_err("running cpufreq without cooling device: %ld\n",
220                                PTR_ERR(cdev));
221         }
222 
223         return 0;
224 
225 err_cpufreq_reg:
226         dev_err(&pdev->dev, "failed to register cpufreq driver\n");
227         regulator_put(arm_regulator);
228 err_vdd_arm:
229         kfree(exynos_info);
230         return -EINVAL;
231 }
232 
233 static struct platform_driver exynos_cpufreq_platdrv = {
234         .driver = {
235                 .name   = "exynos-cpufreq",
236         },
237         .probe = exynos_cpufreq_probe,
238 };
239 module_platform_driver(exynos_cpufreq_platdrv);
240 

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