linux/arch/arm/kernel/cpuidle.c

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/*
* Copyright 2012 Linaro Ltd.
*
* The code contained herein is licensed under the GNU General Public
* License. You may obtain a copy of the GNU General Public License
* Version 2 or later at the following locations:
*
* http://www.opensource.org/licenses/gpl-license.html
* http://www.gnu.org/copyleft/gpl.html
*/
#include <linux/cpuidle.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <asm/cpuidle.h>
extern struct of_cpuidle_method __cpuidle_method_of_table[];
static const struct of_cpuidle_method __cpuidle_method_of_table_sentinel
__used __section(__cpuidle_method_of_table_end);
static struct cpuidle_ops cpuidle_ops[NR_CPUS];
int arm_cpuidle_simple_enter(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index)
{
cpu_do_idle();
return index;
}
int arm_cpuidle_suspend(int index)
{
int ret = -EOPNOTSUPP;
int cpu = smp_processor_id();
if (cpuidle_ops[cpu].suspend)
ret = cpuidle_ops[cpu].suspend(cpu, index);
return ret;
}
static struct cpuidle_ops *__init arm_cpuidle_get_ops(const char *method)
{
struct of_cpuidle_method *m = __cpuidle_method_of_table;
for (; m->method; m++)
if (!strcmp(m->method, method))
return m->ops;
return NULL;
}
static int __init arm_cpuidle_read_ops(struct device_node *dn, int cpu)
{
const char *enable_method;
struct cpuidle_ops *ops;
enable_method = of_get_property(dn, "enable-method", NULL);
if (!enable_method)
return -ENOENT;
ops = arm_cpuidle_get_ops(enable_method);
if (!ops) {
pr_warn("%s: unsupported enable-method property: %s\n",
dn->full_name, enable_method);
return -EOPNOTSUPP;
}
cpuidle_ops[cpu] = *ops; /* structure copy */
pr_notice("cpuidle: enable-method property '%s'"
" found operations\n", enable_method);
return 0;
}
int __init arm_cpuidle_init(int cpu)
{
struct device_node *cpu_node = of_cpu_device_node_get(cpu);
int ret;
if (!cpu_node)
return -ENODEV;
ret = arm_cpuidle_read_ops(cpu_node, cpu);
if (!ret && cpuidle_ops[cpu].init)
ret = cpuidle_ops[cpu].init(cpu_node, cpu);
of_node_put(cpu_node);
return ret;
}