linux/drivers/cpufreq/loongson2_cpufreq.c
Viresh Kumar 9c0ebcf78f cpufreq: Implement light weight ->target_index() routine
Currently, the prototype of cpufreq_drivers target routines is:

int target(struct cpufreq_policy *policy, unsigned int target_freq,
		unsigned int relation);

And most of the drivers call cpufreq_frequency_table_target() to get a valid
index of their frequency table which is closest to the target_freq. And they
don't use target_freq and relation after that.

So, it makes sense to just do this work in cpufreq core before calling
cpufreq_frequency_table_target() and simply pass index instead. But this can be
done only with drivers which expose their frequency table with cpufreq core. For
others we need to stick with the old prototype of target() until those drivers
are converted to expose frequency tables.

This patch implements the new light weight prototype for target_index() routine.
It looks like this:

int target_index(struct cpufreq_policy *policy, unsigned int index);

CPUFreq core will call cpufreq_frequency_table_target() before calling this
routine and pass index to it. Because CPUFreq core now requires to call routines
present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time.

This also marks target() interface as deprecated. So, that new drivers avoid
using it. And Documentation is updated accordingly.

It also converts existing .target() to newly defined light weight
.target_index() routine for many driver.

Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Russell King <linux@arm.linux.org.uk>
Acked-by: David S. Miller <davem@davemloft.net>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
2013-10-25 22:42:24 +02:00

224 lines
5.2 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 index)
{
unsigned int cpu = policy->cpu;
cpumask_t cpus_allowed;
struct cpufreq_freqs freqs;
unsigned int freq;
cpus_allowed = current->cpus_allowed;
set_cpus_allowed_ptr(current, cpumask_of(cpu));
freq =
((cpu_clock_freq / 1000) *
loongson2_clockmod_table[index].driver_data) / 8;
pr_debug("cpufreq: requested frequency %u Hz\n",
loongson2_clockmod_table[index].frequency * 1000);
freqs.old = loongson2_cpufreq_get(cpu);
freqs.new = freq;
freqs.flags = 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_generic_init(policy, &loongson2_clockmod_table[0], 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_index = 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");