cpuidle.c

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/*
 * Copyright 2012 Freescale Semiconductor, Inc.
 * 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/err.h>
#include <linux/hrtimer.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/slab.h>

static struct cpuidle_device __percpu * imx_cpuidle_devices;

static void __init imx_cpuidle_devices_uninit(void)
{
    int cpu_id;
    struct cpuidle_device *dev;

    for_each_possible_cpu(cpu_id) {
        dev = per_cpu_ptr(imx_cpuidle_devices, cpu_id);
        cpuidle_unregister_device(dev);
    }

    free_percpu(imx_cpuidle_devices);
}

int __init imx_cpuidle_init(struct cpuidle_driver *drv)
{
    struct cpuidle_device *dev;
    int cpu_id, ret;

    if (drv->state_count > CPUIDLE_STATE_MAX) {
        pr_err("%s: state_count exceeds maximum\n", __func__);
        return -EINVAL;
    }

    ret = cpuidle_register_driver(drv);
    if (ret) {
        pr_err("%s: Failed to register cpuidle driver with error: %d\n",
             __func__, ret);
        return ret;
    }

    imx_cpuidle_devices = alloc_percpu(struct cpuidle_device);
    if (imx_cpuidle_devices == NULL) {
        ret = -ENOMEM;
        goto unregister_drv;
    }

    /* initialize state data for each cpuidle_device */
    for_each_possible_cpu(cpu_id) {
        dev = per_cpu_ptr(imx_cpuidle_devices, cpu_id);
        dev->cpu = cpu_id;
        dev->state_count = drv->state_count;

        ret = cpuidle_register_device(dev);
        if (ret) {
            pr_err("%s: Failed to register cpu %u, error: %d\n",
                __func__, cpu_id, ret);
            goto uninit;
        }
    }

    return 0;

uninit:
    imx_cpuidle_devices_uninit();

unregister_drv:
    cpuidle_unregister_driver(drv);
    return ret;
}