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) 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 * struct drm_modeset_lock - used for locking modeset resources. 66 * @mutex: resource locking 67 * @head: used to hold it's place on &drm_atomi_state.locked list when 68 * part of an atomic update 69 * 70 * Used for locking CRTCs and other modeset resources. 71 */ 72 struct drm_modeset_lock { 73 /* 74 * modeset lock 75 */ 76 struct ww_mutex mutex; 77 78 /* 79 * Resources that are locked as part of an atomic update are added 80 * to a list (so we know what to unlock at the end). 81 */ 82 struct list_head head; 83 }; 84 85 void drm_modeset_acquire_init(struct drm_modeset_acquire_ctx *ctx, 86 uint32_t flags); 87 void drm_modeset_acquire_fini(struct drm_modeset_acquire_ctx *ctx); 88 void drm_modeset_drop_locks(struct drm_modeset_acquire_ctx *ctx); 89 void drm_modeset_backoff(struct drm_modeset_acquire_ctx *ctx); 90 int drm_modeset_backoff_interruptible(struct drm_modeset_acquire_ctx *ctx); 91 92 void drm_modeset_lock_init(struct drm_modeset_lock *lock); 93 94 /** 95 * drm_modeset_lock_fini - cleanup lock 96 * @lock: lock to cleanup 97 */ 98 static inline void drm_modeset_lock_fini(struct drm_modeset_lock *lock) 99 { 100 WARN_ON(!list_empty(&lock->head)); 101 } 102 103 /** 104 * drm_modeset_is_locked - equivalent to mutex_is_locked() 105 * @lock: lock to check 106 */ 107 static inline bool drm_modeset_is_locked(struct drm_modeset_lock *lock) 108 { 109 return ww_mutex_is_locked(&lock->mutex); 110 } 111 112 int drm_modeset_lock(struct drm_modeset_lock *lock, 113 struct drm_modeset_acquire_ctx *ctx); 114 int drm_modeset_lock_interruptible(struct drm_modeset_lock *lock, 115 struct drm_modeset_acquire_ctx *ctx); 116 void drm_modeset_unlock(struct drm_modeset_lock *lock); 117 118 struct drm_device; 119 struct drm_crtc; 120 struct drm_plane; 121 122 void drm_modeset_lock_all(struct drm_device *dev); 123 void drm_modeset_unlock_all(struct drm_device *dev); 124 void drm_warn_on_modeset_not_all_locked(struct drm_device *dev); 125 126 int drm_modeset_lock_all_ctx(struct drm_device *dev, 127 struct drm_modeset_acquire_ctx *ctx); 128 129 #endif /* DRM_MODESET_LOCK_H_ */ 130