common.c

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/*
 * drivers/base/power/common.c - Common device power management code.
 *
 * Copyright (C) 2011 Rafael J. Wysocki <[email protected]>, Renesas Electronics Corp.
 *
 * This file is released under the GPLv2.
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/pm_clock.h>

int dev_pm_get_subsys_data(struct device *dev)
{
    struct pm_subsys_data *psd;

    psd = kzalloc(sizeof(*psd), GFP_KERNEL);
    if (!psd)
        return -ENOMEM;

    spin_lock_irq(&dev->power.lock);

    if (dev->power.subsys_data) {
        dev->power.subsys_data->refcount++;
    } else {
        spin_lock_init(&psd->lock);
        psd->refcount = 1;
        dev->power.subsys_data = psd;
        pm_clk_init(dev);
        psd = NULL;
    }

    spin_unlock_irq(&dev->power.lock);

    /* kfree() verifies that its argument is nonzero. */
    kfree(psd);

    return 0;
}
EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data);

int dev_pm_put_subsys_data(struct device *dev)
{
    struct pm_subsys_data *psd;
    int ret = 0;

    spin_lock_irq(&dev->power.lock);

    psd = dev_to_psd(dev);
    if (!psd) {
        ret = -EINVAL;
        goto out;
    }

    if (--psd->refcount == 0) {
        dev->power.subsys_data = NULL;
        kfree(psd);
        ret = 1;
    }

 out:
    spin_unlock_irq(&dev->power.lock);

    return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);