1/*
 2 * drivers/base/power/common.c - Common device power management code.
 3 *
 4 * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
 5 *
 6 * This file is released under the GPLv2.
 7 */
 8
 9#include <linux/init.h>
10#include <linux/kernel.h>
11#include <linux/device.h>
12#include <linux/export.h>
13#include <linux/slab.h>
14#include <linux/pm_clock.h>
15
16/**
17 * dev_pm_get_subsys_data - Create or refcount power.subsys_data for device.
18 * @dev: Device to handle.
19 *
20 * If power.subsys_data is NULL, point it to a new object, otherwise increment
21 * its reference counter.  Return 1 if a new object has been created, otherwise
22 * return 0 or error code.
23 */
24int dev_pm_get_subsys_data(struct device *dev)
25{
26	struct pm_subsys_data *psd;
27	int ret = 0;
28
29	psd = kzalloc(sizeof(*psd), GFP_KERNEL);
30	if (!psd)
31		return -ENOMEM;
32
33	spin_lock_irq(&dev->power.lock);
34
35	if (dev->power.subsys_data) {
36		dev->power.subsys_data->refcount++;
37	} else {
38		spin_lock_init(&psd->lock);
39		psd->refcount = 1;
40		dev->power.subsys_data = psd;
41		pm_clk_init(dev);
42		psd = NULL;
43		ret = 1;
44	}
45
46	spin_unlock_irq(&dev->power.lock);
47
48	/* kfree() verifies that its argument is nonzero. */
49	kfree(psd);
50
51	return ret;
52}
53EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data);
54
55/**
56 * dev_pm_put_subsys_data - Drop reference to power.subsys_data.
57 * @dev: Device to handle.
58 *
59 * If the reference counter of power.subsys_data is zero after dropping the
60 * reference, power.subsys_data is removed.  Return 1 if that happens or 0
61 * otherwise.
62 */
63int dev_pm_put_subsys_data(struct device *dev)
64{
65	struct pm_subsys_data *psd;
66	int ret = 0;
67
68	spin_lock_irq(&dev->power.lock);
69
70	psd = dev_to_psd(dev);
71	if (!psd) {
72		ret = -EINVAL;
73		goto out;
74	}
75
76	if (--psd->refcount == 0) {
77		dev->power.subsys_data = NULL;
78		kfree(psd);
79		ret = 1;
80	}
81
82 out:
83	spin_unlock_irq(&dev->power.lock);
84
85	return ret;
86}
87EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);