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Diffstat (limited to 'kernel/include/drm/drm_modeset_lock.h')
| -rw-r--r-- | kernel/include/drm/drm_modeset_lock.h | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/kernel/include/drm/drm_modeset_lock.h b/kernel/include/drm/drm_modeset_lock.h new file mode 100644 index 000000000..70595ff56 --- /dev/null +++ b/kernel/include/drm/drm_modeset_lock.h @@ -0,0 +1,145 @@ +/* + * 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_ */ |