linux/drivers/cpufreq/loongson2_cpufreq.c
Viresh Kumar adbed6e847 cpufreq: loongson2: don't initialize part of policy set by core
Many common initializations of struct policy are moved to core now and hence
this driver doesn't need to do it. This patch removes such code.

Most recent of those changes is to call ->get() in the core after calling
->init().

Cc: John Crispin <blogic@openwrt.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-16 00:50:30 +02:00

236 lines
5.5 KiB
C

/*
* Cpufreq driver for the loongson-2 processors
*
* The 2E revision of loongson processor not support this feature.
*
* Copyright (C) 2006 - 2008 Lemote Inc. & Insititute of Computing Technology
* Author: Yanhua, yanh@lemote.com
*
* 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.
*/
#include <linux/cpufreq.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/sched.h> /* set_cpus_allowed() */
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <asm/clock.h>
#include <asm/idle.h>
#include <asm/mach-loongson/loongson.h>
static uint nowait;
static struct clk *cpuclk;
static void (*saved_cpu_wait) (void);
static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
unsigned long val, void *data);
static struct notifier_block loongson2_cpufreq_notifier_block = {
.notifier_call = loongson2_cpu_freq_notifier
};
static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
unsigned long val, void *data)
{
if (val == CPUFREQ_POSTCHANGE)
current_cpu_data.udelay_val = loops_per_jiffy;
return 0;
}
static unsigned int loongson2_cpufreq_get(unsigned int cpu)
{
return clk_get_rate(cpuclk);
}
/*
* Here we notify other drivers of the proposed change and the final change.
*/
static int loongson2_cpufreq_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
unsigned int cpu = policy->cpu;
unsigned int newstate = 0;
cpumask_t cpus_allowed;
struct cpufreq_freqs freqs;
unsigned int freq;
cpus_allowed = current->cpus_allowed;
set_cpus_allowed_ptr(current, cpumask_of(cpu));
if (cpufreq_frequency_table_target
(policy, &loongson2_clockmod_table[0], target_freq, relation,
&newstate))
return -EINVAL;
freq =
((cpu_clock_freq / 1000) *
loongson2_clockmod_table[newstate].driver_data) / 8;
if (freq < policy->min || freq > policy->max)
return -EINVAL;
pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000);
freqs.old = loongson2_cpufreq_get(cpu);
freqs.new = freq;
freqs.flags = 0;
if (freqs.new == freqs.old)
return 0;
/* notifiers */
cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
set_cpus_allowed_ptr(current, &cpus_allowed);
/* setting the cpu frequency */
clk_set_rate(cpuclk, freq);
/* notifiers */
cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
pr_debug("cpufreq: set frequency %u kHz\n", freq);
return 0;
}
static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
int i;
unsigned long rate;
int ret;
cpuclk = clk_get(NULL, "cpu_clk");
if (IS_ERR(cpuclk)) {
printk(KERN_ERR "cpufreq: couldn't get CPU clk\n");
return PTR_ERR(cpuclk);
}
rate = cpu_clock_freq / 1000;
if (!rate) {
clk_put(cpuclk);
return -EINVAL;
}
/* clock table init */
for (i = 2;
(loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
i++)
loongson2_clockmod_table[i].frequency = (rate * i) / 8;
ret = clk_set_rate(cpuclk, rate);
if (ret) {
clk_put(cpuclk);
return ret;
}
return cpufreq_table_validate_and_show(policy,
&loongson2_clockmod_table[0]);
}
static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
{
cpufreq_frequency_table_put_attr(policy->cpu);
clk_put(cpuclk);
return 0;
}
static struct cpufreq_driver loongson2_cpufreq_driver = {
.name = "loongson2",
.init = loongson2_cpufreq_cpu_init,
.verify = cpufreq_generic_frequency_table_verify,
.target = loongson2_cpufreq_target,
.get = loongson2_cpufreq_get,
.exit = loongson2_cpufreq_exit,
.attr = cpufreq_generic_attr,
};
static struct platform_device_id platform_device_ids[] = {
{
.name = "loongson2_cpufreq",
},
{}
};
MODULE_DEVICE_TABLE(platform, platform_device_ids);
static struct platform_driver platform_driver = {
.driver = {
.name = "loongson2_cpufreq",
.owner = THIS_MODULE,
},
.id_table = platform_device_ids,
};
/*
* This is the simple version of Loongson-2 wait, Maybe we need do this in
* interrupt disabled context.
*/
static DEFINE_SPINLOCK(loongson2_wait_lock);
static void loongson2_cpu_wait(void)
{
unsigned long flags;
u32 cpu_freq;
spin_lock_irqsave(&loongson2_wait_lock, flags);
cpu_freq = LOONGSON_CHIPCFG0;
LOONGSON_CHIPCFG0 &= ~0x7; /* Put CPU into wait mode */
LOONGSON_CHIPCFG0 = cpu_freq; /* Restore CPU state */
spin_unlock_irqrestore(&loongson2_wait_lock, flags);
local_irq_enable();
}
static int __init cpufreq_init(void)
{
int ret;
/* Register platform stuff */
ret = platform_driver_register(&platform_driver);
if (ret)
return ret;
pr_info("cpufreq: Loongson-2F CPU frequency driver.\n");
cpufreq_register_notifier(&loongson2_cpufreq_notifier_block,
CPUFREQ_TRANSITION_NOTIFIER);
ret = cpufreq_register_driver(&loongson2_cpufreq_driver);
if (!ret && !nowait) {
saved_cpu_wait = cpu_wait;
cpu_wait = loongson2_cpu_wait;
}
return ret;
}
static void __exit cpufreq_exit(void)
{
if (!nowait && saved_cpu_wait)
cpu_wait = saved_cpu_wait;
cpufreq_unregister_driver(&loongson2_cpufreq_driver);
cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block,
CPUFREQ_TRANSITION_NOTIFIER);
platform_driver_unregister(&platform_driver);
}
module_init(cpufreq_init);
module_exit(cpufreq_exit);
module_param(nowait, uint, 0644);
MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait");
MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
MODULE_DESCRIPTION("cpufreq driver for Loongson2F");
MODULE_LICENSE("GPL");