2 * Copyright (c) 2010-2011 Samsung Electronics Co., Ltd.
3 * http://www.samsung.com
5 * EXYNOS - CPU frequency scaling support for EXYNOS series
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.
12 #include <linux/kernel.h>
13 #include <linux/err.h>
14 #include <linux/clk.h>
16 #include <linux/slab.h>
17 #include <linux/regulator/consumer.h>
18 #include <linux/cpufreq.h>
19 #include <linux/suspend.h>
23 #include "exynos-cpufreq.h"
25 static struct exynos_dvfs_info *exynos_info;
27 static struct regulator *arm_regulator;
28 static struct cpufreq_freqs freqs;
30 static unsigned int locking_frequency;
31 static bool frequency_locked;
32 static DEFINE_MUTEX(cpufreq_lock);
34 static int exynos_verify_speed(struct cpufreq_policy *policy)
36 return cpufreq_frequency_table_verify(policy,
37 exynos_info->freq_table);
40 static unsigned int exynos_getspeed(unsigned int cpu)
42 return clk_get_rate(exynos_info->cpu_clk) / 1000;
45 static int exynos_cpufreq_get_index(unsigned int freq)
47 struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
51 freq_table[index].frequency != CPUFREQ_TABLE_END; index++)
52 if (freq_table[index].frequency == freq)
55 if (freq_table[index].frequency == CPUFREQ_TABLE_END)
61 static int exynos_cpufreq_scale(unsigned int target_freq)
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;
71 freqs.old = policy->cur;
72 freqs.new = target_freq;
73 freqs.cpu = policy->cpu;
75 if (freqs.new == freqs.old)
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.
83 old_index = exynos_cpufreq_get_index(freqs.old);
89 index = exynos_cpufreq_get_index(target_freq);
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
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];
106 arm_volt = volt_table[index];
108 for_each_cpu(freqs.cpu, policy->cpus)
109 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
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);
116 pr_err("%s: failed to set cpu voltage to %d\n",
123 ret = regulator_set_voltage(arm_regulator, safe_arm_volt,
126 pr_err("%s: failed to set cpu voltage to %d\n",
127 __func__, safe_arm_volt);
132 exynos_info->set_freq(old_index, index);
134 for_each_cpu(freqs.cpu, policy->cpus)
135 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
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,
144 pr_err("%s: failed to set cpu voltage to %d\n",
152 cpufreq_cpu_put(policy);
157 static int exynos_target(struct cpufreq_policy *policy,
158 unsigned int target_freq,
159 unsigned int relation)
161 struct cpufreq_frequency_table *freq_table = exynos_info->freq_table;
163 unsigned int new_freq;
166 mutex_lock(&cpufreq_lock);
168 if (frequency_locked)
171 if (cpufreq_frequency_table_target(policy, freq_table,
172 target_freq, relation, &index)) {
177 new_freq = freq_table[index].frequency;
179 ret = exynos_cpufreq_scale(new_freq);
182 mutex_unlock(&cpufreq_lock);
188 static int exynos_cpufreq_suspend(struct cpufreq_policy *policy)
193 static int exynos_cpufreq_resume(struct cpufreq_policy *policy)
200 * exynos_cpufreq_pm_notifier - block CPUFREQ's activities in suspend-resume
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
214 static int exynos_cpufreq_pm_notifier(struct notifier_block *notifier,
215 unsigned long pm_event, void *v)
220 case PM_SUSPEND_PREPARE:
221 mutex_lock(&cpufreq_lock);
222 frequency_locked = true;
223 mutex_unlock(&cpufreq_lock);
225 ret = exynos_cpufreq_scale(locking_frequency);
231 case PM_POST_SUSPEND:
232 mutex_lock(&cpufreq_lock);
233 frequency_locked = false;
234 mutex_unlock(&cpufreq_lock);
241 static struct notifier_block exynos_cpufreq_nb = {
242 .notifier_call = exynos_cpufreq_pm_notifier,
245 static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
247 policy->cur = policy->min = policy->max = exynos_getspeed(policy->cpu);
249 cpufreq_frequency_table_get_attr(exynos_info->freq_table, policy->cpu);
251 /* set the transition latency value */
252 policy->cpuinfo.transition_latency = 100000;
254 cpumask_setall(policy->cpus);
256 return cpufreq_frequency_table_cpuinfo(policy, exynos_info->freq_table);
259 static int exynos_cpufreq_cpu_exit(struct cpufreq_policy *policy)
261 cpufreq_frequency_table_put_attr(policy->cpu);
265 static struct freq_attr *exynos_cpufreq_attr[] = {
266 &cpufreq_freq_attr_scaling_available_freqs,
270 static 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,
280 .suspend = exynos_cpufreq_suspend,
281 .resume = exynos_cpufreq_resume,
285 static int __init exynos_cpufreq_init(void)
289 exynos_info = kzalloc(sizeof(struct exynos_dvfs_info), GFP_KERNEL);
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);
300 pr_err("%s: CPU type not found\n", __func__);
305 if (exynos_info->set_freq == NULL) {
306 pr_err("%s: No set_freq function (ERR)\n", __func__);
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__);
316 locking_frequency = exynos_getspeed(0);
318 register_pm_notifier(&exynos_cpufreq_nb);
320 if (cpufreq_register_driver(&exynos_driver)) {
321 pr_err("%s: failed to register cpufreq driver\n", __func__);
327 unregister_pm_notifier(&exynos_cpufreq_nb);
329 regulator_put(arm_regulator);
332 pr_debug("%s: failed initialization\n", __func__);
335 late_initcall(exynos_cpufreq_init);