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/*
* CPU frequency scaling for OMAP using OPP information
*
* Copyright (C) 2005 Nokia Corporation
* Written by Tony Lindgren <tony@atomide.com>
*
* Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
*
* Copyright (C) 2007-2011 Texas Instruments, Inc.
* - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/opp.h>
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <asm/smp_plat.h>
#include <asm/cpu.h>
#include <plat/omap_device.h>
/* OPP tolerance in percentage */
#define OPP_TOLERANCE 4
static struct cpufreq_frequency_table *freq_table;
static atomic_t freq_table_users = ATOMIC_INIT(0);
static struct clk *mpu_clk;
static struct device *mpu_dev;
static struct regulator *mpu_reg;
static int omap_verify_speed(struct cpufreq_policy *policy)
{
if (!freq_table)
return -EINVAL;
return cpufreq_frequency_table_verify(policy, freq_table);
}
static unsigned int omap_getspeed(unsigned int cpu)
{
unsigned long rate;
if (cpu >= NR_CPUS)
return 0;
rate = clk_get_rate(mpu_clk) / 1000;
return rate;
}
static int omap_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
unsigned int i;
int r, ret = 0;
struct cpufreq_freqs freqs;
struct opp *opp;
unsigned long freq, volt = 0, volt_old = 0, tol = 0;
if (!freq_table) {
dev_err(mpu_dev, "%s: cpu%d: no freq table!\n", __func__,
policy->cpu);
return -EINVAL;
}
ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
relation, &i);
if (ret) {
dev_dbg(mpu_dev, "%s: cpu%d: no freq match for %d(ret=%d)\n",
__func__, policy->cpu, target_freq, ret);
return ret;
}
freqs.new = freq_table[i].frequency;
if (!freqs.new) {
dev_err(mpu_dev, "%s: cpu%d: no match for freq %d\n", __func__,
policy->cpu, target_freq);
return -EINVAL;
}
freqs.old = omap_getspeed(policy->cpu);
freqs.cpu = policy->cpu;
if (freqs.old == freqs.new && policy->cur == freqs.new)
return ret;
/* notifiers */
for_each_cpu(i, policy->cpus) {
freqs.cpu = i;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
}
freq = freqs.new * 1000;
ret = clk_round_rate(mpu_clk, freq);
if (IS_ERR_VALUE(ret)) {
dev_warn(mpu_dev,
"CPUfreq: Cannot find matching frequency for %lu\n",
freq);
return ret;
}
freq = ret;
if (mpu_reg) {
opp = opp_find_freq_ceil(mpu_dev, &freq);
if (IS_ERR(opp)) {
dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
__func__, freqs.new);
return -EINVAL;
}
volt = opp_get_voltage(opp);
tol = volt * OPP_TOLERANCE / 100;
volt_old = regulator_get_voltage(mpu_reg);
}
dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n",
freqs.old / 1000, volt_old ? volt_old / 1000 : -1,
freqs.new / 1000, volt ? volt / 1000 : -1);
/* scaling up? scale voltage before frequency */
if (mpu_reg && (freqs.new > freqs.old)) {
r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
if (r < 0) {
dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
__func__);
freqs.new = freqs.old;
goto done;
}
}
ret = clk_set_rate(mpu_clk, freqs.new * 1000);
/* scaling down? scale voltage after frequency */
if (mpu_reg && (freqs.new < freqs.old)) {
r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
if (r < 0) {
dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
__func__);
ret = clk_set_rate(mpu_clk, freqs.old * 1000);
freqs.new = freqs.old;
goto done;
}
}
freqs.new = omap_getspeed(policy->cpu);
done:
/* notifiers */
for_each_cpu(i, policy->cpus) {
freqs.cpu = i;
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
}
return ret;
}
static inline void freq_table_free(void)
{
if (atomic_dec_and_test(&freq_table_users))
opp_free_cpufreq_table(mpu_dev, &freq_table);
}
static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
{
int result = 0;
mpu_clk = clk_get(NULL, "cpufreq_ck");
if (IS_ERR(mpu_clk))
return PTR_ERR(mpu_clk);
if (policy->cpu >= NR_CPUS) {
result = -EINVAL;
goto fail_ck;
}
policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
if (!freq_table)
result = opp_init_cpufreq_table(mpu_dev, &freq_table);
if (result) {
dev_err(mpu_dev, "%s: cpu%d: failed creating freq table[%d]\n",
__func__, policy->cpu, result);
goto fail_ck;
}
atomic_inc_return(&freq_table_users);
result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
if (result)
goto fail_table;
cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
policy->min = policy->cpuinfo.min_freq;
policy->max = policy->cpuinfo.max_freq;
policy->cur = omap_getspeed(policy->cpu);
/*
* On OMAP SMP configuartion, both processors share the voltage
* and clock. So both CPUs needs to be scaled together and hence
* needs software co-ordination. Use cpufreq affected_cpus
* interface to handle this scenario. Additional is_smp() check
* is to keep SMP_ON_UP build working.
*/
if (is_smp()) {
policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
cpumask_setall(policy->cpus);
}
/* FIXME: what's the actual transition time? */
policy->cpuinfo.transition_latency = 300 * 1000;
return 0;
fail_table:
freq_table_free();
fail_ck:
clk_put(mpu_clk);
return result;
}
static int omap_cpu_exit(struct cpufreq_policy *policy)
{
freq_table_free();
clk_put(mpu_clk);
return 0;
}
static struct freq_attr *omap_cpufreq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
static struct cpufreq_driver omap_driver = {
.flags = CPUFREQ_STICKY,
.verify = omap_verify_speed,
.target = omap_target,
.get = omap_getspeed,
.init = omap_cpu_init,
.exit = omap_cpu_exit,
.name = "omap",
.attr = omap_cpufreq_attr,
};
static int __init omap_cpufreq_init(void)
{
mpu_dev = omap_device_get_by_hwmod_name("mpu");
if (IS_ERR(mpu_dev)) {
pr_warning("%s: unable to get the mpu device\n", __func__);
return PTR_ERR(mpu_dev);
}
mpu_reg = regulator_get(mpu_dev, "vcc");
if (IS_ERR(mpu_reg)) {
pr_warning("%s: unable to get MPU regulator\n", __func__);
mpu_reg = NULL;
} else {
/*
* Ensure physical regulator is present.
* (e.g. could be dummy regulator.)
*/
if (regulator_get_voltage(mpu_reg) < 0) {
pr_warn("%s: physical regulator not present for MPU\n",
__func__);
regulator_put(mpu_reg);
mpu_reg = NULL;
}
}
return cpufreq_register_driver(&omap_driver);
}
static void __exit omap_cpufreq_exit(void)
{
cpufreq_unregister_driver(&omap_driver);
}
MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
MODULE_LICENSE("GPL");
module_init(omap_cpufreq_init);
module_exit(omap_cpufreq_exit);
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