LXR linux/include/drm/drm_modeset

   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
  29struct 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 */
  42struct 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 state->locked list when
  68 *    part of an atomic update
  69 *
  70 * Used for locking CRTCs and other modeset resources.
  71 */
  72struct 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
  85extern struct ww_class crtc_ww_class;
  86
  87void drm_modeset_acquire_init(struct drm_modeset_acquire_ctx *ctx,
  88                uint32_t flags);
  89void drm_modeset_acquire_fini(struct drm_modeset_acquire_ctx *ctx);
  90void drm_modeset_drop_locks(struct drm_modeset_acquire_ctx *ctx);
  91void drm_modeset_backoff(struct drm_modeset_acquire_ctx *ctx);
  92int drm_modeset_backoff_interruptible(struct drm_modeset_acquire_ctx *ctx);
  93
  94/**
  95 * drm_modeset_lock_init - initialize lock
  96 * @lock: lock to init
  97 */
  98static inline void drm_modeset_lock_init(struct drm_modeset_lock *lock)
  99{
 100        ww_mutex_init(&lock->mutex, &crtc_ww_class);
 101        INIT_LIST_HEAD(&lock->head);
 102}
 103
 104/**
 105 * drm_modeset_lock_fini - cleanup lock
 106 * @lock: lock to cleanup
 107 */
 108static 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 */
 117static inline bool drm_modeset_is_locked(struct drm_modeset_lock *lock)
 118{
 119        return ww_mutex_is_locked(&lock->mutex);
 120}
 121
 122int drm_modeset_lock(struct drm_modeset_lock *lock,
 123                struct drm_modeset_acquire_ctx *ctx);
 124int drm_modeset_lock_interruptible(struct drm_modeset_lock *lock,
 125                struct drm_modeset_acquire_ctx *ctx);
 126void drm_modeset_unlock(struct drm_modeset_lock *lock);
 127
 128struct drm_device;
 129struct drm_crtc;
 130struct drm_plane;
 131
 132void drm_modeset_lock_all(struct drm_device *dev);
 133void drm_modeset_unlock_all(struct drm_device *dev);
 134void drm_modeset_lock_crtc(struct drm_crtc *crtc,
 135                           struct drm_plane *plane);
 136void drm_modeset_unlock_crtc(struct drm_crtc *crtc);
 137void drm_warn_on_modeset_not_all_locked(struct drm_device *dev);
 138struct drm_modeset_acquire_ctx *
 139drm_modeset_legacy_acquire_ctx(struct drm_crtc *crtc);
 140
 141int drm_modeset_lock_all_ctx(struct drm_device *dev,
 142                             struct drm_modeset_acquire_ctx *ctx);
 143
 144#endif /* DRM_MODESET_LOCK_H_ */
 145