mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-18 17:54:13 +08:00
fe829ed8ef
The policy->transition_latency field is used for multiple purposes
today and its not straight forward at all. This is how it is used:
A. Set the correct transition_latency value.
B. Set it to CPUFREQ_ETERNAL because:
1. We don't want automatic dynamic switching (with
ondemand/conservative) to happen at all.
2. We don't know the transition latency.
This patch handles the B.1. case in a more readable way. A new flag for
the cpufreq drivers is added to disallow use of cpufreq governors which
have dynamic_switching flag set.
All the current cpufreq drivers which are setting transition_latency
unconditionally to CPUFREQ_ETERNAL are updated to use it. They don't
need to set transition_latency anymore.
There shouldn't be any functional change after this patch.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
80 lines
1.9 KiB
C
80 lines
1.9 KiB
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/err.h>
|
|
#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.
|
|
*/
|
|
static int ucv2_verify_speed(struct cpufreq_policy *policy)
|
|
{
|
|
if (policy->cpu)
|
|
return -EINVAL;
|
|
|
|
cpufreq_verify_within_cpu_limits(policy);
|
|
return 0;
|
|
}
|
|
|
|
static int ucv2_target(struct cpufreq_policy *policy,
|
|
unsigned int target_freq,
|
|
unsigned int relation)
|
|
{
|
|
struct cpufreq_freqs freqs;
|
|
int ret;
|
|
|
|
freqs.old = policy->cur;
|
|
freqs.new = target_freq;
|
|
|
|
cpufreq_freq_transition_begin(policy, &freqs);
|
|
ret = clk_set_rate(policy->clk, target_freq * 1000);
|
|
cpufreq_freq_transition_end(policy, &freqs, ret);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int __init ucv2_cpu_init(struct cpufreq_policy *policy)
|
|
{
|
|
if (policy->cpu != 0)
|
|
return -EINVAL;
|
|
|
|
policy->min = policy->cpuinfo.min_freq = 250000;
|
|
policy->max = policy->cpuinfo.max_freq = 1000000;
|
|
policy->clk = clk_get(NULL, "MAIN_CLK");
|
|
return PTR_ERR_OR_ZERO(policy->clk);
|
|
}
|
|
|
|
static struct cpufreq_driver ucv2_driver = {
|
|
.flags = CPUFREQ_STICKY | CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING,
|
|
.verify = ucv2_verify_speed,
|
|
.target = ucv2_target,
|
|
.get = cpufreq_generic_get,
|
|
.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);
|