sh-cpufreq.c
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/*
* cpufreq driver for the SuperH processors.
*
* Copyright (C) 2002 - 2012 Paul Mundt
* Copyright (C) 2002 M. R. Brown
*
* Clock framework bits from arch/avr32/mach-at32ap/cpufreq.c
*
* Copyright (C) 2004-2007 Atmel Corporation
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#define pr_fmt(fmt) "cpufreq: " fmt
#include <linux/types.h>
#include <linux/cpufreq.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/cpumask.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/sched.h> /* set_cpus_allowed() */
#include <linux/clk.h>
#include <linux/percpu.h>
#include <linux/sh_clk.h>
static DEFINE_PER_CPU(struct clk, sh_cpuclk);
static unsigned int sh_cpufreq_get(unsigned int cpu)
{
return (clk_get_rate(&per_cpu(sh_cpuclk, cpu)) + 500) / 1000;
}
/*
* Here we notify other drivers of the proposed change and the final change.
*/
static int sh_cpufreq_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
unsigned int cpu = policy->cpu;
struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
cpumask_t cpus_allowed;
struct cpufreq_freqs freqs;
struct device *dev;
long freq;
cpus_allowed = current->cpus_allowed;
set_cpus_allowed_ptr(current, cpumask_of(cpu));
BUG_ON(smp_processor_id() != cpu);
dev = get_cpu_device(cpu);
/* Convert target_freq from kHz to Hz */
freq = clk_round_rate(cpuclk, target_freq * 1000);
if (freq < (policy->min * 1000) || freq > (policy->max * 1000))
return -EINVAL;
dev_dbg(dev, "requested frequency %u Hz\n", target_freq * 1000);
freqs.old = sh_cpufreq_get(cpu);
freqs.new = (freq + 500) / 1000;
freqs.flags = 0;
cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
set_cpus_allowed_ptr(current, &cpus_allowed);
clk_set_rate(cpuclk, freq);
cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
dev_dbg(dev, "set frequency %lu Hz\n", freq);
return 0;
}
static int sh_cpufreq_verify(struct cpufreq_policy *policy)
{
struct clk *cpuclk = &per_cpu(sh_cpuclk, policy->cpu);
struct cpufreq_frequency_table *freq_table;
freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
if (freq_table)
return cpufreq_frequency_table_verify(policy, freq_table);
cpufreq_verify_within_cpu_limits(policy);
policy->min = (clk_round_rate(cpuclk, 1) + 500) / 1000;
policy->max = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
cpufreq_verify_within_cpu_limits(policy);
return 0;
}
static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
unsigned int cpu = policy->cpu;
struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
struct cpufreq_frequency_table *freq_table;
struct device *dev;
dev = get_cpu_device(cpu);
cpuclk = clk_get(dev, "cpu_clk");
if (IS_ERR(cpuclk)) {
dev_err(dev, "couldn't get CPU clk\n");
return PTR_ERR(cpuclk);
}
freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
if (freq_table) {
int result;
result = cpufreq_table_validate_and_show(policy, freq_table);
if (result)
return result;
} else {
dev_notice(dev, "no frequency table found, falling back "
"to rate rounding.\n");
policy->min = policy->cpuinfo.min_freq =
(clk_round_rate(cpuclk, 1) + 500) / 1000;
policy->max = policy->cpuinfo.max_freq =
(clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
}
policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
dev_info(dev, "CPU Frequencies - Minimum %u.%03u MHz, "
"Maximum %u.%03u MHz.\n",
policy->min / 1000, policy->min % 1000,
policy->max / 1000, policy->max % 1000);
return 0;
}
static int sh_cpufreq_cpu_exit(struct cpufreq_policy *policy)
{
unsigned int cpu = policy->cpu;
struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
cpufreq_frequency_table_put_attr(cpu);
clk_put(cpuclk);
return 0;
}
static struct cpufreq_driver sh_cpufreq_driver = {
.name = "sh",
.get = sh_cpufreq_get,
.target = sh_cpufreq_target,
.verify = sh_cpufreq_verify,
.init = sh_cpufreq_cpu_init,
.exit = sh_cpufreq_cpu_exit,
.attr = cpufreq_generic_attr,
};
static int __init sh_cpufreq_module_init(void)
{
pr_notice("SuperH CPU frequency driver.\n");
return cpufreq_register_driver(&sh_cpufreq_driver);
}
static void __exit sh_cpufreq_module_exit(void)
{
cpufreq_unregister_driver(&sh_cpufreq_driver);
}
module_init(sh_cpufreq_module_init);
module_exit(sh_cpufreq_module_exit);
MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
MODULE_DESCRIPTION("cpufreq driver for SuperH");
MODULE_LICENSE("GPL");