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/*
* CPU frequency scaling for u8500
* Inspired by linux/arch/arm/mach-davinci/cpufreq.c
*
* 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/platform_device.h>
#include <linux/kernel.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/mfd/db8500-prcmu.h>
#include <mach/hardware.h>
#define DRIVER_NAME "cpufreq-u8500"
#define CPUFREQ_NAME "u8500"
static struct device *dev;
static struct cpufreq_frequency_table freq_table[] = {
[0] = {
.index = 0,
.frequency = 200000,
},
[1] = {
.index = 1,
.frequency = 300000,
},
[2] = {
.index = 2,
.frequency = 600000,
},
[3] = {
/* Used for CPU_OPP_MAX, if available */
.index = 3,
.frequency = CPUFREQ_TABLE_END,
},
[4] = {
.index = 4,
.frequency = CPUFREQ_TABLE_END,
},
};
static enum prcmu_cpu_opp index2opp[] = {
CPU_OPP_EXT_CLK,
CPU_OPP_50,
CPU_OPP_100,
CPU_OPP_MAX
};
static int u8500_cpufreq_verify_speed(struct cpufreq_policy *policy)
{
return cpufreq_frequency_table_verify(policy, freq_table);
}
static int u8500_cpufreq_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
struct cpufreq_freqs freqs;
unsigned int index;
int ret = 0;
/*
* Ensure desired rate is within allowed range. Some govenors
* (ondemand) will just pass target_freq=0 to get the minimum.
*/
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;
ret = cpufreq_frequency_table_target(policy, freq_table,
target_freq, relation, &index);
if (ret < 0) {
dev_err(dev, "Could not look up next frequency\n");
return ret;
}
freqs.old = policy->cur;
freqs.new = freq_table[index].frequency;
freqs.cpu = policy->cpu;
if (freqs.old == freqs.new) {
dev_dbg(dev, "Current and target frequencies are equal\n");
return 0;
}
dev_dbg(dev, "transition: %u --> %u\n", freqs.old, freqs.new);
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
ret = prcmu_set_cpu_opp(index2opp[index]);
if (ret < 0) {
dev_err(dev, "Failed to set OPP level\n");
return ret;
}
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
return ret;
}
static unsigned int u8500_cpufreq_getspeed(unsigned int cpu)
{
int i;
for (i = 0; prcmu_get_cpu_opp() != index2opp[i]; i++)
;
return freq_table[i].frequency;
}
static int __cpuinit u8500_cpu_init(struct cpufreq_policy *policy)
{
int res;
BUILD_BUG_ON(ARRAY_SIZE(index2opp) + 1 != ARRAY_SIZE(freq_table));
if (cpu_is_u8500v2()) {
freq_table[1].frequency = 400000;
freq_table[2].frequency = 800000;
if (prcmu_has_arm_maxopp())
freq_table[3].frequency = 1000000;
}
/* 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 {
dev_err(dev, "u8500-cpufreq : Failed to read policy table\n");
return res;
}
policy->min = policy->cpuinfo.min_freq;
policy->max = policy->cpuinfo.max_freq;
policy->cur = u8500_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 = 200 * 1000; /* in ns */
/* policy sharing between dual CPUs */
cpumask_copy(policy->cpus, &cpu_present_map);
policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
return res;
}
static struct freq_attr *u8500_cpufreq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
static int u8500_cpu_exit(struct cpufreq_policy *policy)
{
cpufreq_frequency_table_put_attr(policy->cpu);
return 0;
}
static struct cpufreq_driver u8500_driver = {
.owner = THIS_MODULE,
.flags = CPUFREQ_STICKY,
.verify = u8500_cpufreq_verify_speed,
.target = u8500_cpufreq_target,
.get = u8500_cpufreq_getspeed,
.init = u8500_cpu_init,
.exit = u8500_cpu_exit,
.name = CPUFREQ_NAME,
.attr = u8500_cpufreq_attr,
};
static int __init u8500_cpufreq_probe(struct platform_device *pdev)
{
dev = &pdev->dev;
return cpufreq_register_driver(&u8500_driver);
}
static int __exit u8500_cpufreq_remove(struct platform_device *pdev)
{
return cpufreq_unregister_driver(&u8500_driver);
}
static struct platform_driver u8500_cpufreq_driver = {
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
},
.remove = __exit_p(u8500_cpufreq_remove),
};
static int __init u8500_cpufreq_init(void)
{
return platform_driver_probe(&u8500_cpufreq_driver,
&u8500_cpufreq_probe);
}
device_initcall(u8500_cpufreq_init);
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