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
;
29 static unsigned int locking_frequency
;
30 static bool frequency_locked
;
31 static DEFINE_MUTEX(cpufreq_lock
);
33 static unsigned int exynos_getspeed(unsigned int cpu
)
35 return clk_get_rate(exynos_info
->cpu_clk
) / 1000;
38 static int exynos_cpufreq_get_index(unsigned int freq
)
40 struct cpufreq_frequency_table
*freq_table
= exynos_info
->freq_table
;
44 freq_table
[index
].frequency
!= CPUFREQ_TABLE_END
; index
++)
45 if (freq_table
[index
].frequency
== freq
)
48 if (freq_table
[index
].frequency
== CPUFREQ_TABLE_END
)
54 static int exynos_cpufreq_scale(unsigned int target_freq
)
56 struct cpufreq_frequency_table
*freq_table
= exynos_info
->freq_table
;
57 unsigned int *volt_table
= exynos_info
->volt_table
;
58 struct cpufreq_policy
*policy
= cpufreq_cpu_get(0);
59 unsigned int arm_volt
, safe_arm_volt
= 0;
60 unsigned int mpll_freq_khz
= exynos_info
->mpll_freq_khz
;
61 unsigned int old_freq
;
65 old_freq
= policy
->cur
;
68 * The policy max have been changed so that we cannot get proper
69 * old_index with cpufreq_frequency_table_target(). Thus, ignore
70 * policy and get the index from the raw frequency table.
72 old_index
= exynos_cpufreq_get_index(old_freq
);
78 index
= exynos_cpufreq_get_index(target_freq
);
85 * ARM clock source will be changed APLL to MPLL temporary
86 * To support this level, need to control regulator for
87 * required voltage level
89 if (exynos_info
->need_apll_change
!= NULL
) {
90 if (exynos_info
->need_apll_change(old_index
, index
) &&
91 (freq_table
[index
].frequency
< mpll_freq_khz
) &&
92 (freq_table
[old_index
].frequency
< mpll_freq_khz
))
93 safe_arm_volt
= volt_table
[exynos_info
->pll_safe_idx
];
95 arm_volt
= volt_table
[index
];
97 /* When the new frequency is higher than current frequency */
98 if ((target_freq
> old_freq
) && !safe_arm_volt
) {
99 /* Firstly, voltage up to increase frequency */
100 ret
= regulator_set_voltage(arm_regulator
, arm_volt
, arm_volt
);
102 pr_err("%s: failed to set cpu voltage to %d\n",
109 ret
= regulator_set_voltage(arm_regulator
, safe_arm_volt
,
112 pr_err("%s: failed to set cpu voltage to %d\n",
113 __func__
, safe_arm_volt
);
118 exynos_info
->set_freq(old_index
, index
);
120 /* When the new frequency is lower than current frequency */
121 if ((target_freq
< old_freq
) ||
122 ((target_freq
> old_freq
) && safe_arm_volt
)) {
123 /* down the voltage after frequency change */
124 ret
= regulator_set_voltage(arm_regulator
, arm_volt
,
127 pr_err("%s: failed to set cpu voltage to %d\n",
134 cpufreq_cpu_put(policy
);
139 static int exynos_target(struct cpufreq_policy
*policy
, unsigned int index
)
141 struct cpufreq_frequency_table
*freq_table
= exynos_info
->freq_table
;
144 mutex_lock(&cpufreq_lock
);
146 if (frequency_locked
)
149 ret
= exynos_cpufreq_scale(freq_table
[index
].frequency
);
152 mutex_unlock(&cpufreq_lock
);
158 static int exynos_cpufreq_suspend(struct cpufreq_policy
*policy
)
163 static int exynos_cpufreq_resume(struct cpufreq_policy
*policy
)
170 * exynos_cpufreq_pm_notifier - block CPUFREQ's activities in suspend-resume
176 * While frequency_locked == true, target() ignores every frequency but
177 * locking_frequency. The locking_frequency value is the initial frequency,
178 * which is set by the bootloader. In order to eliminate possible
179 * inconsistency in clock values, we save and restore frequencies during
180 * suspend and resume and block CPUFREQ activities. Note that the standard
181 * suspend/resume cannot be used as they are too deep (syscore_ops) for
184 static int exynos_cpufreq_pm_notifier(struct notifier_block
*notifier
,
185 unsigned long pm_event
, void *v
)
190 case PM_SUSPEND_PREPARE
:
191 mutex_lock(&cpufreq_lock
);
192 frequency_locked
= true;
193 mutex_unlock(&cpufreq_lock
);
195 ret
= exynos_cpufreq_scale(locking_frequency
);
201 case PM_POST_SUSPEND
:
202 mutex_lock(&cpufreq_lock
);
203 frequency_locked
= false;
204 mutex_unlock(&cpufreq_lock
);
211 static struct notifier_block exynos_cpufreq_nb
= {
212 .notifier_call
= exynos_cpufreq_pm_notifier
,
215 static int exynos_cpufreq_cpu_init(struct cpufreq_policy
*policy
)
217 return cpufreq_generic_init(policy
, exynos_info
->freq_table
, 100000);
220 static struct cpufreq_driver exynos_driver
= {
221 .flags
= CPUFREQ_STICKY
,
222 .verify
= cpufreq_generic_frequency_table_verify
,
223 .target_index
= exynos_target
,
224 .get
= exynos_getspeed
,
225 .init
= exynos_cpufreq_cpu_init
,
226 .exit
= cpufreq_generic_exit
,
227 .name
= "exynos_cpufreq",
228 .attr
= cpufreq_generic_attr
,
230 .suspend
= exynos_cpufreq_suspend
,
231 .resume
= exynos_cpufreq_resume
,
235 static int __init
exynos_cpufreq_init(void)
239 exynos_info
= kzalloc(sizeof(*exynos_info
), GFP_KERNEL
);
243 if (soc_is_exynos4210())
244 ret
= exynos4210_cpufreq_init(exynos_info
);
245 else if (soc_is_exynos4212() || soc_is_exynos4412())
246 ret
= exynos4x12_cpufreq_init(exynos_info
);
247 else if (soc_is_exynos5250())
248 ret
= exynos5250_cpufreq_init(exynos_info
);
255 if (exynos_info
->set_freq
== NULL
) {
256 pr_err("%s: No set_freq function (ERR)\n", __func__
);
260 arm_regulator
= regulator_get(NULL
, "vdd_arm");
261 if (IS_ERR(arm_regulator
)) {
262 pr_err("%s: failed to get resource vdd_arm\n", __func__
);
266 locking_frequency
= exynos_getspeed(0);
268 register_pm_notifier(&exynos_cpufreq_nb
);
270 if (cpufreq_register_driver(&exynos_driver
)) {
271 pr_err("%s: failed to register cpufreq driver\n", __func__
);
277 unregister_pm_notifier(&exynos_cpufreq_nb
);
279 regulator_put(arm_regulator
);
284 late_initcall(exynos_cpufreq_init
);