94 строки
2.2 KiB
C
94 строки
2.2 KiB
C
/*
|
|
* linux/arch/unicore32/kernel/cpu-ucv2.c: clock scaling for the UniCore-II
|
|
*
|
|
* Code specific to PKUnity SoC and UniCore ISA
|
|
*
|
|
* Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
|
|
* Copyright (C) 2001-2010 Guan Xuetao
|
|
*
|
|
* 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/kernel.h>
|
|
#include <linux/types.h>
|
|
#include <linux/init.h>
|
|
#include <linux/clk.h>
|
|
#include <linux/cpufreq.h>
|
|
|
|
#include <mach/hardware.h>
|
|
|
|
static struct cpufreq_driver ucv2_driver;
|
|
|
|
/* make sure that only the "userspace" governor is run
|
|
* -- anything else wouldn't make sense on this platform, anyway.
|
|
*/
|
|
int ucv2_verify_speed(struct cpufreq_policy *policy)
|
|
{
|
|
if (policy->cpu)
|
|
return -EINVAL;
|
|
|
|
cpufreq_verify_within_limits(policy,
|
|
policy->cpuinfo.min_freq, policy->cpuinfo.max_freq);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static unsigned int ucv2_getspeed(unsigned int cpu)
|
|
{
|
|
struct clk *mclk = clk_get(NULL, "MAIN_CLK");
|
|
|
|
if (cpu)
|
|
return 0;
|
|
return clk_get_rate(mclk)/1000;
|
|
}
|
|
|
|
static int ucv2_target(struct cpufreq_policy *policy,
|
|
unsigned int target_freq,
|
|
unsigned int relation)
|
|
{
|
|
unsigned int cur = ucv2_getspeed(0);
|
|
struct cpufreq_freqs freqs;
|
|
struct clk *mclk = clk_get(NULL, "MAIN_CLK");
|
|
|
|
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
|
|
|
|
if (!clk_set_rate(mclk, target_freq * 1000)) {
|
|
freqs.old = cur;
|
|
freqs.new = target_freq;
|
|
freqs.cpu = 0;
|
|
}
|
|
|
|
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __init ucv2_cpu_init(struct cpufreq_policy *policy)
|
|
{
|
|
if (policy->cpu != 0)
|
|
return -EINVAL;
|
|
policy->cur = ucv2_getspeed(0);
|
|
policy->min = policy->cpuinfo.min_freq = 250000;
|
|
policy->max = policy->cpuinfo.max_freq = 1000000;
|
|
policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
|
|
return 0;
|
|
}
|
|
|
|
static struct cpufreq_driver ucv2_driver = {
|
|
.flags = CPUFREQ_STICKY,
|
|
.verify = ucv2_verify_speed,
|
|
.target = ucv2_target,
|
|
.get = ucv2_getspeed,
|
|
.init = ucv2_cpu_init,
|
|
.name = "UniCore-II",
|
|
};
|
|
|
|
static int __init ucv2_cpufreq_init(void)
|
|
{
|
|
return cpufreq_register_driver(&ucv2_driver);
|
|
}
|
|
|
|
arch_initcall(ucv2_cpufreq_init);
|