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