[mirror_ubuntu-bionic-kernel.git] / include / drm / drm_modeset_lock.h

/*
 * 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 &drm_atomi_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;
};

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);

void drm_modeset_lock_init(struct drm_modeset_lock *lock);

/**
 * 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);
void drm_modeset_unlock_all(struct drm_device *dev);
void drm_warn_on_modeset_not_all_locked(struct drm_device *dev);

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

#endif /* DRM_MODESET_LOCK_H_ */
Commit	Line	Data
51fd371b RC	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	/**
f3a80881	32	* struct drm_modeset_acquire_ctx - locking context (see ww_acquire_ctx)
51fd371b RC	33	* @ww_ctx: base acquire ctx
	34	* @contended: used internally for -EDEADLK handling
	35	* @locked: list of held locks
b7a1aafd	36	* @trylock_only: trylock mode used in atomic contexts/panic notifiers
51fd371b RC	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
fe8660ac	46	/*
51fd371b RC	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
fe8660ac	53	/*
51fd371b RC	54	* list of held locks (drm_modeset_lock)
	55	*/
	56	struct list_head locked;
cb597bb3	57
fe8660ac	58	/*
cb597bb3 DV	59	* Trylock mode, use only for panic handlers!
	60	*/
	61	bool trylock_only;
51fd371b RC	62	};
	63
	64	/**
f3a80881	65	* struct drm_modeset_lock - used for locking modeset resources.
51fd371b	66	* @mutex: resource locking
d574528a	67	* @head: used to hold it's place on &drm_atomi_state.locked list when
51fd371b RC	68	* part of an atomic update
	69	*
	70	* Used for locking CRTCs and other modeset resources.
	71	*/
	72	struct drm_modeset_lock {
fe8660ac	73	/*
51fd371b RC	74	* modeset lock
	75	*/
	76	struct ww_mutex mutex;
	77
fe8660ac	78	/*
51fd371b RC	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
51fd371b RC	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
35cf0350	92	void drm_modeset_lock_init(struct drm_modeset_lock *lock);
51fd371b RC	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;
d059f652	119	struct drm_crtc;
4d02e2de	120	struct drm_plane;
a6a8bb84 DV	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
06eaae46 TR	126	int drm_modeset_lock_all_ctx(struct drm_device *dev,
06eaae46 TR	127	struct drm_modeset_acquire_ctx *ctx);
51fd371b RC	128
51fd371b RC	129	#endif /* DRM_MODESET_LOCK_H_ */