Commit | Line | Data |
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4f86d3a8 LB |
1 | /* |
2 | * driver.c - driver support | |
3 | * | |
4 | * (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> | |
5 | * Shaohua Li <shaohua.li@intel.com> | |
6 | * Adam Belay <abelay@novell.com> | |
7 | * | |
8 | * This code is licenced under the GPL. | |
9 | */ | |
10 | ||
11 | #include <linux/mutex.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/cpuidle.h> | |
14 | ||
15 | #include "cpuidle.h" | |
16 | ||
752138df | 17 | static struct cpuidle_driver *cpuidle_curr_driver; |
4f86d3a8 | 18 | DEFINE_SPINLOCK(cpuidle_driver_lock); |
6e797a07 | 19 | int cpuidle_driver_refcount; |
4f86d3a8 | 20 | |
46bcfad7 DD |
21 | static void __cpuidle_register_driver(struct cpuidle_driver *drv) |
22 | { | |
23 | int i; | |
24 | /* | |
25 | * cpuidle driver should set the drv->power_specified bit | |
26 | * before registering if the driver provides | |
27 | * power_usage numbers. | |
28 | * | |
29 | * If power_specified is not set, | |
30 | * we fill in power_usage with decreasing values as the | |
31 | * cpuidle code has an implicit assumption that state Cn | |
32 | * uses less power than C(n-1). | |
33 | * | |
34 | * With CONFIG_ARCH_HAS_CPU_RELAX, C0 is already assigned | |
35 | * an power value of -1. So we use -2, -3, etc, for other | |
36 | * c-states. | |
37 | */ | |
38 | if (!drv->power_specified) { | |
39 | for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) | |
40 | drv->states[i].power_usage = -1 - i; | |
41 | } | |
42 | } | |
43 | ||
44 | ||
4f86d3a8 LB |
45 | /** |
46 | * cpuidle_register_driver - registers a driver | |
47 | * @drv: the driver | |
48 | */ | |
49 | int cpuidle_register_driver(struct cpuidle_driver *drv) | |
50 | { | |
fc850f39 | 51 | if (!drv || !drv->state_count) |
4f86d3a8 LB |
52 | return -EINVAL; |
53 | ||
62027aea LB |
54 | if (cpuidle_disabled()) |
55 | return -ENODEV; | |
56 | ||
4f86d3a8 LB |
57 | spin_lock(&cpuidle_driver_lock); |
58 | if (cpuidle_curr_driver) { | |
59 | spin_unlock(&cpuidle_driver_lock); | |
60 | return -EBUSY; | |
61 | } | |
46bcfad7 | 62 | __cpuidle_register_driver(drv); |
4f86d3a8 LB |
63 | cpuidle_curr_driver = drv; |
64 | spin_unlock(&cpuidle_driver_lock); | |
65 | ||
66 | return 0; | |
67 | } | |
68 | ||
69 | EXPORT_SYMBOL_GPL(cpuidle_register_driver); | |
70 | ||
752138df LB |
71 | /** |
72 | * cpuidle_get_driver - return the current driver | |
73 | */ | |
74 | struct cpuidle_driver *cpuidle_get_driver(void) | |
75 | { | |
76 | return cpuidle_curr_driver; | |
77 | } | |
78 | EXPORT_SYMBOL_GPL(cpuidle_get_driver); | |
79 | ||
4f86d3a8 LB |
80 | /** |
81 | * cpuidle_unregister_driver - unregisters a driver | |
82 | * @drv: the driver | |
83 | */ | |
84 | void cpuidle_unregister_driver(struct cpuidle_driver *drv) | |
85 | { | |
c0d64cb0 LB |
86 | if (drv != cpuidle_curr_driver) { |
87 | WARN(1, "invalid cpuidle_unregister_driver(%s)\n", | |
88 | drv->name); | |
4f86d3a8 | 89 | return; |
c0d64cb0 | 90 | } |
4f86d3a8 LB |
91 | |
92 | spin_lock(&cpuidle_driver_lock); | |
6e797a07 RW |
93 | |
94 | if (!WARN_ON(cpuidle_driver_refcount > 0)) | |
95 | cpuidle_curr_driver = NULL; | |
96 | ||
4f86d3a8 LB |
97 | spin_unlock(&cpuidle_driver_lock); |
98 | } | |
99 | ||
100 | EXPORT_SYMBOL_GPL(cpuidle_unregister_driver); | |
6e797a07 RW |
101 | |
102 | struct cpuidle_driver *cpuidle_driver_ref(void) | |
103 | { | |
104 | struct cpuidle_driver *drv; | |
105 | ||
106 | spin_lock(&cpuidle_driver_lock); | |
107 | ||
108 | drv = cpuidle_curr_driver; | |
109 | cpuidle_driver_refcount++; | |
110 | ||
111 | spin_unlock(&cpuidle_driver_lock); | |
112 | return drv; | |
113 | } | |
114 | ||
115 | void cpuidle_driver_unref(void) | |
116 | { | |
117 | spin_lock(&cpuidle_driver_lock); | |
118 | ||
119 | if (!WARN_ON(cpuidle_driver_refcount <= 0)) | |
120 | cpuidle_driver_refcount--; | |
121 | ||
122 | spin_unlock(&cpuidle_driver_lock); | |
123 | } |