summaryrefslogtreecommitdiffstats
path: root/kernel/include/drm/drm_modeset_lock.h
blob: 70595ff565baa45190faaae5c42630fe04a1beff (plain)
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
134
135
136
137
138
139
140
141
142
143
144
145
/*
 * Copyright (C) 2014 Red Hat
 * Author: Rob Clark <robdclark@gmail.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef DRM_MODESET_LOCK_H_
#define DRM_MODESET_LOCK_H_

#include <linux/ww_mutex.h>

struct drm_modeset_lock;

/**
 * struct drm_modeset_acquire_ctx - locking context (see ww_acquire_ctx)
 * @ww_ctx: base acquire ctx
 * @contended: used internally for -EDEADLK handling
 * @locked: list of held locks
 * @trylock_only: trylock mode used in atomic contexts/panic notifiers
 *
 * Each thread competing for a set of locks must use one acquire
 * ctx.  And if any lock fxn returns -EDEADLK, it must backoff and
 * retry.
 */
struct drm_modeset_acquire_ctx {

	struct ww_acquire_ctx ww_ctx;

	/**
	 * Contended lock: if a lock is contended you should only call
	 * drm_modeset_backoff() which drops locks and slow-locks the
	 * contended lock.
	 */
	struct drm_modeset_lock *contended;

	/**
	 * list of held locks (drm_modeset_lock)
	 */
	struct list_head locked;

	/**
	 * Trylock mode, use only for panic handlers!
	 */
	bool trylock_only;
};

/**
 * struct drm_modeset_lock - used for locking modeset resources.
 * @mutex: resource locking
 * @head: used to hold it's place on state->locked list when
 *    part of an atomic update
 *
 * Used for locking CRTCs and other modeset resources.
 */
struct drm_modeset_lock {
	/**
	 * modeset lock
	 */
	struct ww_mutex mutex;

	/**
	 * Resources that are locked as part of an atomic update are added
	 * to a list (so we know what to unlock at the end).
	 */
	struct list_head head;
};

extern struct ww_class crtc_ww_class;

void drm_modeset_acquire_init(struct drm_modeset_acquire_ctx *ctx,
		uint32_t flags);
void drm_modeset_acquire_fini(struct drm_modeset_acquire_ctx *ctx);
void drm_modeset_drop_locks(struct drm_modeset_acquire_ctx *ctx);
void drm_modeset_backoff(struct drm_modeset_acquire_ctx *ctx);
int drm_modeset_backoff_interruptible(struct drm_modeset_acquire_ctx *ctx);

/**
 * drm_modeset_lock_init - initialize lock
 * @lock: lock to init
 */
static inline void drm_modeset_lock_init(struct drm_modeset_lock *lock)
{
	ww_mutex_init(&lock->mutex, &crtc_ww_class);
	INIT_LIST_HEAD(&lock->head);
}

/**
 * drm_modeset_lock_fini - cleanup lock
 * @lock: lock to cleanup
 */
static inline void drm_modeset_lock_fini(struct drm_modeset_lock *lock)
{
	WARN_ON(!list_empty(&lock->head));
}

/**
 * drm_modeset_is_locked - equivalent to mutex_is_locked()
 * @lock: lock to check
 */
static inline bool drm_modeset_is_locked(struct drm_modeset_lock *lock)
{
	return ww_mutex_is_locked(&lock->mutex);
}

int drm_modeset_lock(struct drm_modeset_lock *lock,
		struct drm_modeset_acquire_ctx *ctx);
int drm_modeset_lock_interruptible(struct drm_modeset_lock *lock,
		struct drm_modeset_acquire_ctx *ctx);
void drm_modeset_unlock(struct drm_modeset_lock *lock);

struct drm_device;
struct drm_crtc;
struct drm_plane;

void drm_modeset_lock_all(struct drm_device *dev);
int __drm_modeset_lock_all(struct drm_device *dev, bool trylock);
void drm_modeset_unlock_all(struct drm_device *dev);
void drm_modeset_lock_crtc(struct drm_crtc *crtc,
			   struct drm_plane *plane);
void drm_modeset_unlock_crtc(struct drm_crtc *crtc);
void drm_warn_on_modeset_not_all_locked(struct drm_device *dev);
struct drm_modeset_acquire_ctx *
drm_modeset_legacy_acquire_ctx(struct drm_crtc *crtc);

int drm_modeset_lock_all_crtcs(struct drm_device *dev,
		struct drm_modeset_acquire_ctx *ctx);

#endif /* DRM_MODESET_LOCK_H_ */