108 lines
2.5 KiB
C
108 lines
2.5 KiB
C
/*
|
|
* Generic big.LITTLE CPUFreq Interface driver
|
|
*
|
|
* It provides necessary ops to arm_big_little cpufreq driver and gets
|
|
* Frequency information from Device Tree. Freq table in DT must be in KHz.
|
|
*
|
|
* Copyright (C) 2013 Linaro.
|
|
* Viresh Kumar <viresh.kumar@linaro.org>
|
|
*
|
|
* 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.
|
|
*
|
|
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
|
|
* kind, whether express or implied; without even the implied warranty
|
|
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
#include <linux/cpufreq.h>
|
|
#include <linux/device.h>
|
|
#include <linux/export.h>
|
|
#include <linux/module.h>
|
|
#include <linux/of.h>
|
|
#include <linux/opp.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/types.h>
|
|
#include "arm_big_little.h"
|
|
|
|
static int dt_init_opp_table(struct device *cpu_dev)
|
|
{
|
|
struct device_node *np, *parent;
|
|
int count = 0, ret;
|
|
|
|
parent = of_find_node_by_path("/cpus");
|
|
if (!parent) {
|
|
pr_err("failed to find OF /cpus\n");
|
|
return -ENOENT;
|
|
}
|
|
|
|
for_each_child_of_node(parent, np) {
|
|
if (count++ != cpu_dev->id)
|
|
continue;
|
|
if (!of_get_property(np, "operating-points", NULL)) {
|
|
ret = -ENODATA;
|
|
} else {
|
|
cpu_dev->of_node = np;
|
|
ret = of_init_opp_table(cpu_dev);
|
|
}
|
|
of_node_put(np);
|
|
of_node_put(parent);
|
|
|
|
return ret;
|
|
}
|
|
|
|
return -ENODEV;
|
|
}
|
|
|
|
static int dt_get_transition_latency(struct device *cpu_dev)
|
|
{
|
|
struct device_node *np, *parent;
|
|
u32 transition_latency = CPUFREQ_ETERNAL;
|
|
int count = 0;
|
|
|
|
parent = of_find_node_by_path("/cpus");
|
|
if (!parent) {
|
|
pr_err("failed to find OF /cpus\n");
|
|
return -ENOENT;
|
|
}
|
|
|
|
for_each_child_of_node(parent, np) {
|
|
if (count++ != cpu_dev->id)
|
|
continue;
|
|
|
|
of_property_read_u32(np, "clock-latency", &transition_latency);
|
|
of_node_put(np);
|
|
of_node_put(parent);
|
|
|
|
return 0;
|
|
}
|
|
|
|
return -ENODEV;
|
|
}
|
|
|
|
static struct cpufreq_arm_bL_ops dt_bL_ops = {
|
|
.name = "dt-bl",
|
|
.get_transition_latency = dt_get_transition_latency,
|
|
.init_opp_table = dt_init_opp_table,
|
|
};
|
|
|
|
static int generic_bL_init(void)
|
|
{
|
|
return bL_cpufreq_register(&dt_bL_ops);
|
|
}
|
|
module_init(generic_bL_init);
|
|
|
|
static void generic_bL_exit(void)
|
|
{
|
|
return bL_cpufreq_unregister(&dt_bL_ops);
|
|
}
|
|
module_exit(generic_bL_exit);
|
|
|
|
MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
|
|
MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver via DT");
|
|
MODULE_LICENSE("GPL");
|