1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2019 Intel Corporation
*/
#ifndef INTEL_WAKEREF_H
#define INTEL_WAKEREF_H
#include <linux/atomic.h>
#include <linux/mutex.h>
#include <linux/stackdepot.h>
struct drm_i915_private;
typedef depot_stack_handle_t intel_wakeref_t;
struct intel_wakeref {
atomic_t count;
struct mutex mutex;
intel_wakeref_t wakeref;
};
void __intel_wakeref_init(struct intel_wakeref *wf,
struct lock_class_key *key);
#define intel_wakeref_init(wf) do { \
static struct lock_class_key __key; \
\
__intel_wakeref_init((wf), &__key); \
} while (0)
int __intel_wakeref_get_first(struct drm_i915_private *i915,
struct intel_wakeref *wf,
int (*fn)(struct intel_wakeref *wf));
int __intel_wakeref_put_last(struct drm_i915_private *i915,
struct intel_wakeref *wf,
int (*fn)(struct intel_wakeref *wf));
/**
* intel_wakeref_get: Acquire the wakeref
* @i915: the drm_i915_private device
* @wf: the wakeref
* @fn: callback for acquired the wakeref, called only on first acquire.
*
* Acquire a hold on the wakeref. The first user to do so, will acquire
* the runtime pm wakeref and then call the @fn underneath the wakeref
* mutex.
*
* Note that @fn is allowed to fail, in which case the runtime-pm wakeref
* will be released and the acquisition unwound, and an error reported.
*
* Returns: 0 if the wakeref was acquired successfully, or a negative error
* code otherwise.
*/
static inline int
intel_wakeref_get(struct drm_i915_private *i915,
struct intel_wakeref *wf,
int (*fn)(struct intel_wakeref *wf))
{
if (unlikely(!atomic_inc_not_zero(&wf->count)))
return __intel_wakeref_get_first(i915, wf, fn);
return 0;
}
/**
* intel_wakeref_put: Release the wakeref
* @i915: the drm_i915_private device
* @wf: the wakeref
* @fn: callback for releasing the wakeref, called only on final release.
*
* Release our hold on the wakeref. When there are no more users,
* the runtime pm wakeref will be released after the @fn callback is called
* underneath the wakeref mutex.
*
* Note that @fn is allowed to fail, in which case the runtime-pm wakeref
* is retained and an error reported.
*
* Returns: 0 if the wakeref was released successfully, or a negative error
* code otherwise.
*/
static inline int
intel_wakeref_put(struct drm_i915_private *i915,
struct intel_wakeref *wf,
int (*fn)(struct intel_wakeref *wf))
{
if (atomic_dec_and_mutex_lock(&wf->count, &wf->mutex))
return __intel_wakeref_put_last(i915, wf, fn);
return 0;
}
/**
* intel_wakeref_lock: Lock the wakeref (mutex)
* @wf: the wakeref
*
* Locks the wakeref to prevent it being acquired or released. New users
* can still adjust the counter, but the wakeref itself (and callback)
* cannot be acquired or released.
*/
static inline void
intel_wakeref_lock(struct intel_wakeref *wf)
__acquires(wf->mutex)
{
mutex_lock(&wf->mutex);
}
/**
* intel_wakeref_unlock: Unlock the wakeref
* @wf: the wakeref
*
* Releases a previously acquired intel_wakeref_lock().
*/
static inline void
intel_wakeref_unlock(struct intel_wakeref *wf)
__releases(wf->mutex)
{
mutex_unlock(&wf->mutex);
}
/**
* intel_wakeref_active: Query whether the wakeref is currently held
* @wf: the wakeref
*
* Returns: true if the wakeref is currently held.
*/
static inline bool
intel_wakeref_active(struct intel_wakeref *wf)
{
return atomic_read(&wf->count);
}
#endif /* INTEL_WAKEREF_H */
|
