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/*
* Copyright (C) STMicroelectronics 2009
* Copyright (C) ST-Ericsson SA 2010
*
* License Terms: GNU General Public License v2
* Author: Sundar Iyer <sundar.iyer@stericsson.com>
* Author: Martin Persson <martin.persson@stericsson.com>
* Author: Jonas Aaberg <jonas.aberg@stericsson.com>
*
*/
#include <linux/kernel.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/mfd/dbx500-prcmu.h>
#include <mach/id.h>
static struct cpufreq_frequency_table freq_table[] = {
[0] = {
.index = 0,
.frequency = 200000,
},
[1] = {
.index = 1,
.frequency = 400000,
},
[2] = {
.index = 2,
.frequency = 800000,
},
[3] = {
/* Used for MAX_OPP, if available */
.index = 3,
.frequency = CPUFREQ_TABLE_END,
},
[4] = {
.index = 4,
.frequency = CPUFREQ_TABLE_END,
},
};
static enum arm_opp idx2opp[] = {
ARM_EXTCLK,
ARM_50_OPP,
ARM_100_OPP,
ARM_MAX_OPP
};
static struct freq_attr *db8500_cpufreq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
static int db8500_cpufreq_verify_speed(struct cpufreq_policy *policy)
{
return cpufreq_frequency_table_verify(policy, freq_table);
}
static int db8500_cpufreq_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
struct cpufreq_freqs freqs;
unsigned int idx;
/* scale the target frequency to one of the extremes supported */
if (target_freq < policy->cpuinfo.min_freq)
target_freq = policy->cpuinfo.min_freq;
if (target_freq > policy->cpuinfo.max_freq)
target_freq = policy->cpuinfo.max_freq;
/* Lookup the next frequency */
if (cpufreq_frequency_table_target
(policy, freq_table, target_freq, relation, &idx)) {
return -EINVAL;
}
freqs.old = policy->cur;
freqs.new = freq_table[idx].frequency;
if (freqs.old == freqs.new)
return 0;
/* pre-change notification */
for_each_cpu(freqs.cpu, policy->cpus)
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
/* request the PRCM unit for opp change */
if (prcmu_set_arm_opp(idx2opp[idx])) {
pr_err("db8500-cpufreq: Failed to set OPP level\n");
return -EINVAL;
}
/* post change notification */
for_each_cpu(freqs.cpu, policy->cpus)
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
return 0;
}
static unsigned int db8500_cpufreq_getspeed(unsigned int cpu)
{
int i;
/* request the prcm to get the current ARM opp */
for (i = 0; prcmu_get_arm_opp() != idx2opp[i]; i++)
;
return freq_table[i].frequency;
}
static int __cpuinit db8500_cpufreq_init(struct cpufreq_policy *policy)
{
int i, res;
BUILD_BUG_ON(ARRAY_SIZE(idx2opp) + 1 != ARRAY_SIZE(freq_table));
if (prcmu_has_arm_maxopp())
freq_table[3].frequency = 1000000;
pr_info("db8500-cpufreq : Available frequencies:\n");
for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
pr_info(" %d Mhz\n", freq_table[i].frequency/1000);
/* get policy fields based on the table */
res = cpufreq_frequency_table_cpuinfo(policy, freq_table);
if (!res)
cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
else {
pr_err("db8500-cpufreq : Failed to read policy table\n");
return res;
}
policy->min = policy->cpuinfo.min_freq;
policy->max = policy->cpuinfo.max_freq;
policy->cur = db8500_cpufreq_getspeed(policy->cpu);
policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
/*
* FIXME : Need to take time measurement across the target()
* function with no/some/all drivers in the notification
* list.
*/
policy->cpuinfo.transition_latency = 20 * 1000; /* in ns */
/* policy sharing between dual CPUs */
cpumask_copy(policy->cpus, &cpu_present_map);
policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
return 0;
}
static struct cpufreq_driver db8500_cpufreq_driver = {
.flags = CPUFREQ_STICKY,
.verify = db8500_cpufreq_verify_speed,
.target = db8500_cpufreq_target,
.get = db8500_cpufreq_getspeed,
.init = db8500_cpufreq_init,
.name = "DB8500",
.attr = db8500_cpufreq_attr,
};
static int __init db8500_cpufreq_register(void)
{
if (!cpu_is_u8500v20_or_later())
return -ENODEV;
pr_info("cpufreq for DB8500 started\n");
return cpufreq_register_driver(&db8500_cpufreq_driver);
}
device_initcall(db8500_cpufreq_register);
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