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 * struct 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 * @trylock_only: trylock mode used in atomic contexts/panic notifiers 37 * 38 * Each thread competing for a set of locks must use one acquire 39 * ctx. And if any lock fxn returns -EDEADLK, it must backoff and 40 * retry. 41 */ 42 struct drm_modeset_acquire_ctx { 43 44 struct ww_acquire_ctx ww_ctx; 45 46 /* 47 * Contended lock: if a lock is contended you should only call 48 * drm_modeset_backoff() which drops locks and slow-locks the 49 * contended lock. 50 */ 51 struct drm_modeset_lock *contended; 52 53 /* 54 * list of held locks (drm_modeset_lock_info) 55 */ 56 struct list_head locked; 57 58 /** 59 * Trylock mode, use only for panic handlers! 60 */ 61 bool trylock_only; 62 }; 63 64 /* 65 * Keep track of extra locks. 66 */ 67 struct drm_modeset_lock_info { 68 struct list_head ctx_entry; 69 struct list_head lock_entry; 70 struct drm_modeset_lock *lock; 71 struct drm_modeset_acquire_ctx *ctx; 72 }; 73 74 /** 75 * struct drm_modeset_lock - used for locking modeset resources. 76 * @mutex: resource locking 77 * @head: used to hold it's place on &drm_atomi_state.locked list when 78 * part of an atomic update 79 * 80 * Used for locking CRTCs and other modeset resources. 81 */ 82 struct drm_modeset_lock { 83 /* 84 * modeset lock 85 */ 86 struct ww_mutex mutex; 87 88 /* 89 * Resources that are locked as part of an atomic update are added 90 * to a list (so we know what to unlock at the end). 91 */ 92 struct list_head head; 93 }; 94 95 void drm_modeset_acquire_init(struct drm_modeset_acquire_ctx *ctx, 96 uint32_t flags); 97 void drm_modeset_acquire_fini(struct drm_modeset_acquire_ctx *ctx); 98 void drm_modeset_drop_locks(struct drm_modeset_acquire_ctx *ctx); 99 void drm_modeset_backoff(struct drm_modeset_acquire_ctx *ctx); 100 int drm_modeset_backoff_interruptible(struct drm_modeset_acquire_ctx *ctx); 101 102 void drm_modeset_lock_init(struct drm_modeset_lock *lock); 103 104 /** 105 * drm_modeset_lock_fini - cleanup lock 106 * @lock: lock to cleanup 107 */ 108 static inline void drm_modeset_lock_fini(struct drm_modeset_lock *lock) 109 { 110 WARN_ON(!list_empty(&lock->head)); 111 } 112 113 /** 114 * drm_modeset_is_locked - equivalent to mutex_is_locked() 115 * @lock: lock to check 116 */ 117 static inline bool drm_modeset_is_locked(struct drm_modeset_lock *lock) 118 { 119 return ww_mutex_is_locked(&lock->mutex); 120 } 121 122 int drm_modeset_lock(struct drm_modeset_lock *lock, 123 struct drm_modeset_acquire_ctx *ctx); 124 int drm_modeset_lock_interruptible(struct drm_modeset_lock *lock, 125 struct drm_modeset_acquire_ctx *ctx); 126 void drm_modeset_unlock(struct drm_modeset_lock *lock); 127 128 struct drm_device; 129 struct drm_crtc; 130 struct drm_plane; 131 132 void drm_modeset_lock_all(struct drm_device *dev); 133 int __drm_modeset_lock_all(struct drm_device *dev, bool trylock); 134 void drm_modeset_unlock_all(struct drm_device *dev); 135 void drm_warn_on_modeset_not_all_locked(struct drm_device *dev); 136 137 int drm_modeset_lock_all_ctx(struct drm_device *dev, 138 struct drm_modeset_acquire_ctx *ctx); 139 140 #endif /* DRM_MODESET_LOCK_H_ */ 141