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 * 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 * Trylock mode, use only for panic handlers! 59 */ 60 bool trylock_only; 61 }; 62 63 /** 64 * struct drm_modeset_lock - used for locking modeset resources. 65 * @mutex: resource locking 66 * @head: used to hold it's place on state->locked list when 67 * part of an atomic update 68 * 69 * Used for locking CRTCs and other modeset resources. 70 */ 71 struct drm_modeset_lock { 72 /** 73 * modeset lock 74 */ 75 struct ww_mutex mutex; 76 77 /** 78 * Resources that are locked as part of an atomic update are added 79 * to a list (so we know what to unlock at the end). 80 */ 81 struct list_head head; 82 }; 83 84 extern struct ww_class crtc_ww_class; 85 86 void drm_modeset_acquire_init(struct drm_modeset_acquire_ctx *ctx, 87 uint32_t flags); 88 void drm_modeset_acquire_fini(struct drm_modeset_acquire_ctx *ctx); 89 void drm_modeset_drop_locks(struct drm_modeset_acquire_ctx *ctx); 90 void drm_modeset_backoff(struct drm_modeset_acquire_ctx *ctx); 91 int drm_modeset_backoff_interruptible(struct drm_modeset_acquire_ctx *ctx); 92 93 /** 94 * drm_modeset_lock_init - initialize lock 95 * @lock: lock to init 96 */ 97 static inline void drm_modeset_lock_init(struct drm_modeset_lock *lock) 98 { 99 ww_mutex_init(&lock->mutex, &crtc_ww_class); 100 INIT_LIST_HEAD(&lock->head); 101 } 102 103 /** 104 * drm_modeset_lock_fini - cleanup lock 105 * @lock: lock to cleanup 106 */ 107 static inline void drm_modeset_lock_fini(struct drm_modeset_lock *lock) 108 { 109 WARN_ON(!list_empty(&lock->head)); 110 } 111 112 /** 113 * drm_modeset_is_locked - equivalent to mutex_is_locked() 114 * @lock: lock to check 115 */ 116 static inline bool drm_modeset_is_locked(struct drm_modeset_lock *lock) 117 { 118 return ww_mutex_is_locked(&lock->mutex); 119 } 120 121 int drm_modeset_lock(struct drm_modeset_lock *lock, 122 struct drm_modeset_acquire_ctx *ctx); 123 int drm_modeset_lock_interruptible(struct drm_modeset_lock *lock, 124 struct drm_modeset_acquire_ctx *ctx); 125 void drm_modeset_unlock(struct drm_modeset_lock *lock); 126 127 struct drm_device; 128 struct drm_crtc; 129 130 void drm_modeset_lock_all(struct drm_device *dev); 131 void drm_modeset_unlock_all(struct drm_device *dev); 132 void drm_modeset_lock_crtc(struct drm_crtc *crtc); 133 void drm_modeset_unlock_crtc(struct drm_crtc *crtc); 134 void drm_warn_on_modeset_not_all_locked(struct drm_device *dev); 135 struct drm_modeset_acquire_ctx * 136 drm_modeset_legacy_acquire_ctx(struct drm_crtc *crtc); 137 138 int drm_modeset_lock_all_crtcs(struct drm_device *dev, 139 struct drm_modeset_acquire_ctx *ctx); 140 141 #endif /* DRM_MODESET_LOCK_H_ */ 142