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