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ef27bed1 RW |
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> | |
51990e82 | 11 | #include <linux/device.h> |
aaf19544 | 12 | #include <linux/export.h> |
ef27bed1 | 13 | #include <linux/slab.h> |
b5e8d269 | 14 | #include <linux/pm_clock.h> |
ef27bed1 RW |
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 | */ | |
24 | int dev_pm_get_subsys_data(struct device *dev) | |
25 | { | |
26 | struct pm_subsys_data *psd; | |
ef27bed1 RW |
27 | |
28 | psd = kzalloc(sizeof(*psd), GFP_KERNEL); | |
29 | if (!psd) | |
30 | return -ENOMEM; | |
31 | ||
32 | spin_lock_irq(&dev->power.lock); | |
33 | ||
34 | if (dev->power.subsys_data) { | |
35 | dev->power.subsys_data->refcount++; | |
36 | } else { | |
37 | spin_lock_init(&psd->lock); | |
38 | psd->refcount = 1; | |
39 | dev->power.subsys_data = psd; | |
40 | pm_clk_init(dev); | |
41 | psd = NULL; | |
ef27bed1 RW |
42 | } |
43 | ||
44 | spin_unlock_irq(&dev->power.lock); | |
45 | ||
46 | /* kfree() verifies that its argument is nonzero. */ | |
47 | kfree(psd); | |
48 | ||
77254950 | 49 | return 0; |
ef27bed1 RW |
50 | } |
51 | EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data); | |
52 | ||
53 | /** | |
54 | * dev_pm_put_subsys_data - Drop reference to power.subsys_data. | |
55 | * @dev: Device to handle. | |
56 | * | |
57 | * If the reference counter of power.subsys_data is zero after dropping the | |
58 | * reference, power.subsys_data is removed. Return 1 if that happens or 0 | |
59 | * otherwise. | |
60 | */ | |
61 | int dev_pm_put_subsys_data(struct device *dev) | |
62 | { | |
63 | struct pm_subsys_data *psd; | |
64 | int ret = 0; | |
65 | ||
66 | spin_lock_irq(&dev->power.lock); | |
67 | ||
68 | psd = dev_to_psd(dev); | |
69 | if (!psd) { | |
70 | ret = -EINVAL; | |
71 | goto out; | |
72 | } | |
73 | ||
74 | if (--psd->refcount == 0) { | |
75 | dev->power.subsys_data = NULL; | |
76 | kfree(psd); | |
77 | ret = 1; | |
78 | } | |
79 | ||
80 | out: | |
81 | spin_unlock_irq(&dev->power.lock); | |
82 | ||
83 | return ret; | |
84 | } | |
85 | EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data); |