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51fd371b RC |
1 | /* |
2 | * Copyright (C) 2014 Red Hat | |
3 | * Author: Rob Clark <robdclark@gmail.com> | |
4 | * | |
5 | * Permission is hereby granted, free of charge, to any person obtaining a | |
6 | * copy of this software and associated documentation files (the "Software"), | |
7 | * to deal in the Software without restriction, including without limitation | |
8 | * the rights to use, copy, modify, merge, publish, distribute, sublicense, | |
9 | * and/or sell copies of the Software, and to permit persons to whom the | |
10 | * Software is furnished to do so, subject to the following conditions: | |
11 | * | |
12 | * The above copyright notice and this permission notice shall be included in | |
13 | * all copies or substantial portions of the Software. | |
14 | * | |
15 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
16 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
17 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
18 | * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR | |
19 | * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, | |
20 | * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR | |
21 | * OTHER DEALINGS IN THE SOFTWARE. | |
22 | */ | |
23 | ||
24 | #ifndef DRM_MODESET_LOCK_H_ | |
25 | #define DRM_MODESET_LOCK_H_ | |
26 | ||
27 | #include <linux/ww_mutex.h> | |
28 | ||
29 | struct drm_modeset_lock; | |
30 | ||
31 | /** | |
32 | * drm_modeset_acquire_ctx - locking context (see ww_acquire_ctx) | |
33 | * @ww_ctx: base acquire ctx | |
34 | * @contended: used internally for -EDEADLK handling | |
35 | * @locked: list of held locks | |
36 | * | |
37 | * Each thread competing for a set of locks must use one acquire | |
38 | * ctx. And if any lock fxn returns -EDEADLK, it must backoff and | |
39 | * retry. | |
40 | */ | |
41 | struct drm_modeset_acquire_ctx { | |
42 | ||
43 | struct ww_acquire_ctx ww_ctx; | |
44 | ||
45 | /** | |
46 | * Contended lock: if a lock is contended you should only call | |
47 | * drm_modeset_backoff() which drops locks and slow-locks the | |
48 | * contended lock. | |
49 | */ | |
50 | struct drm_modeset_lock *contended; | |
51 | ||
52 | /** | |
53 | * list of held locks (drm_modeset_lock) | |
54 | */ | |
55 | struct list_head locked; | |
56 | }; | |
57 | ||
58 | /** | |
59 | * drm_modeset_lock - used for locking modeset resources. | |
60 | * @mutex: resource locking | |
61 | * @head: used to hold it's place on state->locked list when | |
62 | * part of an atomic update | |
63 | * | |
64 | * Used for locking CRTCs and other modeset resources. | |
65 | */ | |
66 | struct drm_modeset_lock { | |
67 | /** | |
68 | * modeset lock | |
69 | */ | |
70 | struct ww_mutex mutex; | |
71 | ||
72 | /** | |
73 | * Resources that are locked as part of an atomic update are added | |
74 | * to a list (so we know what to unlock at the end). | |
75 | */ | |
76 | struct list_head head; | |
77 | }; | |
78 | ||
79 | extern struct ww_class crtc_ww_class; | |
80 | ||
81 | void drm_modeset_acquire_init(struct drm_modeset_acquire_ctx *ctx, | |
82 | uint32_t flags); | |
83 | void drm_modeset_acquire_fini(struct drm_modeset_acquire_ctx *ctx); | |
84 | void drm_modeset_drop_locks(struct drm_modeset_acquire_ctx *ctx); | |
85 | void drm_modeset_backoff(struct drm_modeset_acquire_ctx *ctx); | |
86 | int drm_modeset_backoff_interruptible(struct drm_modeset_acquire_ctx *ctx); | |
87 | ||
88 | /** | |
89 | * drm_modeset_lock_init - initialize lock | |
90 | * @lock: lock to init | |
91 | */ | |
92 | static inline void drm_modeset_lock_init(struct drm_modeset_lock *lock) | |
93 | { | |
94 | ww_mutex_init(&lock->mutex, &crtc_ww_class); | |
95 | INIT_LIST_HEAD(&lock->head); | |
96 | } | |
97 | ||
98 | /** | |
99 | * drm_modeset_lock_fini - cleanup lock | |
100 | * @lock: lock to cleanup | |
101 | */ | |
102 | static inline void drm_modeset_lock_fini(struct drm_modeset_lock *lock) | |
103 | { | |
104 | WARN_ON(!list_empty(&lock->head)); | |
105 | } | |
106 | ||
107 | /** | |
108 | * drm_modeset_is_locked - equivalent to mutex_is_locked() | |
109 | * @lock: lock to check | |
110 | */ | |
111 | static inline bool drm_modeset_is_locked(struct drm_modeset_lock *lock) | |
112 | { | |
113 | return ww_mutex_is_locked(&lock->mutex); | |
114 | } | |
115 | ||
116 | int drm_modeset_lock(struct drm_modeset_lock *lock, | |
117 | struct drm_modeset_acquire_ctx *ctx); | |
118 | int drm_modeset_lock_interruptible(struct drm_modeset_lock *lock, | |
119 | struct drm_modeset_acquire_ctx *ctx); | |
120 | void drm_modeset_unlock(struct drm_modeset_lock *lock); | |
121 | ||
122 | struct drm_device; | |
123 | int drm_modeset_lock_all_crtcs(struct drm_device *dev, | |
124 | struct drm_modeset_acquire_ctx *ctx); | |
125 | ||
126 | #endif /* DRM_MODESET_LOCK_H_ */ |